diff --git a/_index.db b/_index.db index dbfabdf9c..4c91302a1 100644 Binary files a/_index.db and b/_index.db differ diff --git a/data/en.wikipedia.org/wiki/Across_the_Universe_(message)-0.md b/data/en.wikipedia.org/wiki/Across_the_Universe_(message)-0.md new file mode 100644 index 000000000..8b1ef3ce9 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Across_the_Universe_(message)-0.md @@ -0,0 +1,20 @@ +--- +title: "Across the Universe (message)" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Across_the_Universe_(message)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:31.629429+00:00" +instance: "kb-cron" +--- + +Across the Universe is an interstellar radio message (IRM) consisting of the song "Across the Universe" by the Beatles that was transmitted on 4 February 2008, at 00:00 UTC by NASA in the direction of the star Polaris. This transmission was made using a 70-meter "DSS-63" dish in the NASA Deep Space Network's (DSN) Madrid Deep Space Communication Complex, located in Robledo, near Madrid, Spain. The transmission ran in the 4.2-cm band (around 7.14 GHz, C band) at a power of 18 kilowatt. The format was digital, transmitted at a rate of 128 kbps, lasting 3.6 minutes – the normal speed and data rate for a digital recording on Earth. +This action was done in order to celebrate the 40th anniversary of the song's recording, the 45th anniversary of the DSN, and the 50th anniversary of NASA. The idea was hatched by Beatles historian Martin Lewis, who encouraged all Beatles fans to play the track as it was beamed towards the distant star. The event marked the third time a song had ever been intentionally transmitted into deep space (the first being Russia's Teen Age Message in 2001, and the second being the 2003 Cosmic Call 2 message which included "Starman" by David Bowie and music from the Hungarian band KFT), and was approved by Paul McCartney, Yoko Ono, and Apple Records. +A. L. Zaitsev, part of the Teen Age Message project, argues that the NASA project is only a publicity stunt. The compressed digital format used makes the data more fragile to errors compared to TAM's analogue approach, not to mention aliens would not have knowledge on human audio compression algorithms. The transmission data rate is also too high to allow for a remote radio station to faithfully receive; a data rate 300,000 times lower would be required. Finally, the choice of Polaris also makes the message unlikely to reach any alien lifeform should they exist. + + +== See also == +List of interstellar radio messages + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Active_SETI-0.md b/data/en.wikipedia.org/wiki/Active_SETI-0.md new file mode 100644 index 000000000..9cddb9349 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Active_SETI-0.md @@ -0,0 +1,29 @@ +--- +title: "Active SETI" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Active_SETI" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:29.258655+00:00" +instance: "kb-cron" +--- + +Active SETI (Active Search for Extra-Terrestrial Intelligence) are attempts to send messages to intelligent extraterrestrial life. Active SETI messages are predominantly sent in the form of radio signals. Physical messages like that of the Pioneer plaque may also be considered an active SETI message. Active SETI is also known as METI (Messaging to Extra-Terrestrial Intelligence). Whether humans should engage in Active SETI is controversial due to concerns about potential impacts of extraterrestrial contact, sparking a vigorous policy debate. + +== History == +'Active SETI' was a term as early as 2005, though some decades after the term SETI. The term METI was coined in 2006 by Russian scientist Alexander Zaitsev, who proposed a subtle distinction between Active SETI and METI: + +The science known as SETI deals with searching for messages from aliens. METI deals with the creation and transmission of messages to aliens. Thus, SETI and METI proponents have quite different perspectives. SETI scientists are in a position to address only the local question “does Active SETI make sense?” In other words, would it be reasonable, for SETI success, to transmit with the object of attracting ETI's attention? In contrast to Active SETI, METI pursues not a local, but a more global purpose – to overcome the Great Silence in the Universe, bringing to our extraterrestrial neighbors the long-expected annunciation “You are not alone!” +Concern over METI was raised by the science journal Nature in an editorial in October 2006, which commented on a recent meeting of the International Academy of Astronautics SETI study group. The editor said, "It is not obvious that all extraterrestrial civilizations will be benign, or that contact with even a benign one would not have serious repercussions". In the same year, astronomer and science fiction author David Brin expressed similar concerns. In 2013 Brin amended his initial article based on the recent developments in METI. +In 2010, Douglas A. Vakoch from SETI Institute, addressed concerns about the validity of Active SETI alone as an experimental science by proposing the integration of Active SETI and Passive SETI programs to engage in a clearly articulated, ongoing, and evolving set of experiments to test various versions of the Zoo hypothesis, including specific dates at which a first response to messages sent to particular stars could be expected. +On 13 February 2015, scientists including Douglas Vakoch, David Grinspoon, Seth Shostak, and David Brin at an annual meeting of the American Association for the Advancement of Science discussed Active SETI, and whether transmitting a message to possible intelligent extraterrestrials in the Cosmos was a good idea. That same week, a statement was released, signed by many in the SETI community including Berkeley SETI Research Center director Andrew Siemion, advocating that a "worldwide scientific, political and humanitarian discussion must occur before any message is sent". +In July 2015, the Breakthrough Message program was announced. This was an open competition to design a digital message that could be transmitted from Earth to an extraterrestrial civilization, with a US$1,000,000 prize pool. The message was to be "representative of humanity and planet Earth". The program pledged "not to transmit any message until there has been a wide-ranging debate at high levels of science and politics on the risks and rewards of contacting advanced civilizations". + +== Rationale for METI == +In the paper Rationale for METI, transmission of the information into the Cosmos is treated as one of the pressing needs of an advanced civilization. This view is not universally accepted, and it is not agreed with by those who are against the transmission of interstellar radio messages, but at the same time are not against SETI searching. Such duality is called the SETI Paradox. + +== Radio message construction == +The lack of an established communications protocol is a challenge for METI. While trying to synthesize and project an Interstellar Radio Message (IRM), the receiving extraterrestrials (ETs) will first encounter a physical phenomenon and, only after that, perceive the information. Initially, a receiving system will detect the radio signal; then the issue of the extraction of the received information and comprehension of the obtained message will arise. Therefore, above all, the constructor of an IRM should be concerned about the ease of signal determination. In other words, the signal should have maximum openness, which is understood here as an antonym of the term security. This branch of signal synthesis is termed anticryptography. +To this end, in 2010, Michael W. Busch created a general-purpose binary language, later used in the Lone Signal project to transmit crowdsourced messages to extraterrestrial intelligence. Busch developed the coding scheme +and provided Rachel M. Reddick with a test message, in a blind test of decryption. Reddick decoded the entire message after approximately twelve hours of work. This was followed by an attempt to extend the syntax used in the Lone Signal hailing message to communicate in a way that, while neither mathematical nor strictly logical, was nonetheless understandable given the prior definition of terms and concepts in the hailing message. +In addition, characteristics of the radio signal, such as wavelength, type of polarization, and modulation are considered. Over galactic distances, the interstellar medium induces some scintillation effects and artificial modulation of electromagnetic signals. This modulation is higher at lower frequencies and is a function of the sky direction. Over large distances, the depth of the modulation can exceed 100%, making any METI signal very difficult to decode. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Active_SETI-1.md b/data/en.wikipedia.org/wiki/Active_SETI-1.md new file mode 100644 index 000000000..37ca0b23a --- /dev/null +++ b/data/en.wikipedia.org/wiki/Active_SETI-1.md @@ -0,0 +1,37 @@ +--- +title: "Active SETI" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Active_SETI" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:29.258655+00:00" +instance: "kb-cron" +--- + +=== Error correction === +In METI research, any message must have some redundancy, although the exact amount of redundancy and message formats are still in great dispute. Using ideograms, instead of binary sequence, already offers some improvement against noise resistance. In faxlike transmissions, ideograms are spread on many lines. This increases its resistance against short bursts of noise like radio frequency interference or +interstellar scintillation. +One format approach proposed for interstellar messages was to use the product of two prime numbers to construct an image. Unfortunately, this method works only if all the bits are present. As an example, the message sent by Frank Drake from the Arecibo Observatory in 1974 did not have any feature to support mechanisms to cope with the inevitable noise degradation of the interstellar medium. +Error correction tolerance rates for previous METI messages are 9% (one page) for the 1974 Arecibo Message, 44% (23 separate pages) for the 1999 Evpatoria Message, and 46% (one page, estimated) for the 2003 Evpatoria Message. + +==== Examples ==== +The 1999 Cosmic Call transmission was far from being optimal (from a terrestrial viewpoint) as it was essentially a monochromatic signal spiced with supplementary information. Additionally, the message had a very small modulation index overall, a condition not viewed as being optimal for interstellar communication. Over the 370,967 bits (46,371 bytes) sent, some 314,239 were "1" and 56,768 were "0"—5.54 times as many 1's as 0's. Since frequency-shift keying modulation scheme was used, most of the time the signal was on the "0" frequency. In addition, "0" tended to be sent in long stretches, which appeared as white lines in the message. + +== Realized projects == + +The below projects have targeted stars between 17 and 69 light-years from the Earth. The exception is the Arecibo message, which targeted globular cluster M13, approximately 24,000 light-years away. The first interstellar message to reach its destination was the Altair (Morimoto–Hirabayashi) Message, which likely reached its target in 1999. + +The Morse Message (1962) +Arecibo Message (1974) +Cosmic Call 1 (1999) +Teen Age Message (2001) +Cosmic Call 2 (2003) +Across the Universe (2008) +Hello from Earth (2009) +Wow! Reply (2012) +Lone Signal (2013) +A Simple Response to an Elemental Message (2016) +The choice of targets, transmission rate, and encoding may effect how likely a message will be received and interpreted by extraterrestrial intelligence. "Across the Universe" and "A Simple Response to an Elemental Message" were sent to Polaris, which is 431 light years distant from us and whose planetary system, even if it exists, may not be suited for life, because it is a supergiant star, spectral type F7Ib which is only 70 million years old. In addition, both transmission rates were very high, about 128 kbit/s, for such moderate transmitter power (about 18 kW). The main defect of the "Hello From Earth" is an insufficient scientific and technical justification, since no famous SETI scientist made statements with validation of HFE's design. As it follows from [1]: "After the final message was collected on Monday 24 August 2009, messages were exported as a text file and sent to NASA's Jet Propulsion Laboratory in California, where they were encoded into binary, packaged and tested before transmission", but nobody explained why he hopes that such encoded and packaged text will be understood and conceived by possible extraterrestrials. + +== Transmissions == +Below is a table of messages sent and target/destination stars, ordered chronologically by date of sending: \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Active_SETI-2.md b/data/en.wikipedia.org/wiki/Active_SETI-2.md new file mode 100644 index 000000000..313ee997b --- /dev/null +++ b/data/en.wikipedia.org/wiki/Active_SETI-2.md @@ -0,0 +1,52 @@ +--- +title: "Active SETI" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Active_SETI" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:29.258655+00:00" +instance: "kb-cron" +--- + +== Controversy == +Whether or not to conduct Active SETI, as well as the tone of any message, is a highly controversial topic. Active SETI has primarily been criticized due to the perceived risk of revealing the location of the Earth to alien civilizations, without some process of prior international consultation. That is, Active SETI does not meet the criteria for informed consent in a mass experiment involving human subjects and, potentially, nonhuman sentient subjects. +Active SETI is discussed in terms of the ethics of space policy. Issues include whether to send belligerent versus defensive messages, cosmopolitanism, communicative burden, consensus, messaging content, proscriptions on premature messaging, responsibility, and shared values, with concerns that even if successful, humanity could be reduced to a cargo cult. David Brin also urged for an extensive international consultation before any METI activities and has debunked key rationalizations for active SETI (METI), such as the "barn door" argument (unintentional "leaked signals" were millions-fold weaker than intentional METI signals), ignoring/dismissing the precautionary principle (that requires taking extreme precaution e.g. handling extraterrestrial samples even without any known example of risks), and treating METI as being prayer-like which disregards the issue of informed consent from other people. Notable among METI's critics was Stephen Hawking. Hawking, who in his book A Brief History of Time suggests that "alerting" extraterrestrial intelligences to our existence is foolhardy, citing humankind's history of treating its own kind harshly in meetings of civilizations with a significant technology gap, e.g., the extermination of Tasmanian aborigines. He suggested, in view of this history, that we "lay low". Scientist and science fiction author David Brin expressed similar concerns. Similarly, Liu Cixin's trilogy of novels The Remembrance of Earth’s Past Trilogy highlights the potential dangers of METI. +However, some scientists consider these fears about the dangers of METI as panic and irrational superstition; Russian and Soviet radio engineer and astronomer Alexander L. Zaitsev has argued against these concerns. Zaitsev argues that we should consider the risks of not attempting to contact extraterrestrial civilizations, since the knowledge and wisdom an ETI could impart to us would save us from humanity's self-destructive tendencies. Similarly, in a March 2015 essay astronomer Seth Shostak considered the risk and ended by stressing that any danger was hypothetical and that humanity would better off risk contact than "endlessly tremble at the sight of the stars". +Astronomer Jill Tarter also disagrees with Hawking, arguing that aliens developed and long-lived enough to communicate and travel across interstellar distances would have evolved a cooperative and less violent intelligence. She however thinks it is too soon for humans to attempt active SETI and that humans should be more advanced technologically first but keep listening in the meantime. + +To lend a quantitative basis to discussions of the risks of transmitting deliberate messages from Earth, the SETI Permanent Study Group of the International Academy of Astronautics adopted in 2007 a new analytical tool, the San Marino Scale. Developed by Prof. Ivan Almar and Prof. H. Paul Shuch, the San Marino Scale evaluates the significance of transmissions from Earth as a function of signal intensity and information content. Its adoption suggests that not all such transmissions are created equal, thus each must be evaluated separately before establishing a blanket international policy regarding Active SETI. +In 2012, Jacob Haqq-Misra, Michael Busch, Sanjoy Som, and Seth Baum argued that while the benefits of radio communication on Earth likely outweigh the potential harms of detection by extraterrestrial watchers, the uncertainty regarding the outcome of contact with extraterrestrial beings creates difficulty in assessing whether or not to engage in long-term and large-scale METI. +In 2015, in the context of the Zoo Hypothesis, biologist João Pedro de Magalhães proposed transmitting an invitation message to any extraterrestrial intelligences watching us already and inviting them to respond, arguing this would not put us in any more danger than we are already if the Zoo Hypothesis is correct. +Douglas Vakoch, president of METI, argues that passive SETI itself is already an endorsement of active SETI, since "If we detect a signal from aliens through a SETI program, there's no way to prevent a cacophony of responses from Earth." +In the context of potentially detected extraterrestrial activity on Earth, physicist Mark Buchanan argued that humanity needs to determine whether it would be safe or wise to attempt to communicate with extraterrestrials and work on ways to handle such attempts in an organized manner. + +== Beacon proposals == +One proposal for a 10 billion watt interstellar SETI beacon was dismissed by Robert A. Freitas Jr. as being infeasible for a pre-Type I civilization, such as humanity, on the Kardashev scale. However, this 1980s technical argument assumes omni-directional beacons, which may not be the best way to proceed on many technical grounds. Advances in consumer electronics have made possible transmitters that simultaneously transmit many narrow beams, covering the million or so nearest stars but not the spaces between. This multibeam approach can reduce the power and cost to levels that are reasonable with early 21st century Earth technology. +Once civilizations have discovered each other's locations, the energy requirements for maintaining contact and exchanging information can be significantly reduced through the use of highly directional transmission technologies. To this end, a 2018 study estimated a 1–2 megawatt infrared laser focused through a 30-45 meter telescope could be seen from about 20,000 light years away. + +== See also == +Communication with extraterrestrial intelligence +Dark forest hypothesis, the idea that planetary civilizations remain silent to avoid the possibility of contact with potentially aggressive worlds +Detecting Earth from distant star-based systems +METI (Messaging Extraterrestrial Intelligence) – Organization conducting active SETIPages displaying short descriptions of redirect targets +SETIcon – Public conventions on the search for extraterrestrial intelligence +SETI@home +Wow! signal + +== References == + +== External links == + +Interstellar Radio Messages +ActiveSETI.org Archived 2010-09-30 at the Wayback Machine +active-seti.info +Making a Case for METI +Self-Decoding Messages +Should We Shout Into the Darkness? +Error Correction Schemes In Active SETI +The Evpatoria Messages +Encounter 2001 Message +Zaitsev, Alexander L. (2011). "METI: Messaging to ExtraTerrestrial Intelligence". Searching for Extraterrestrial Intelligence. The Frontiers Collection. pp. 399–428. doi:10.1007/978-3-642-13196-7_21. ISBN 978-3-642-13195-0. +The Pros and Cons of METI from Centauri Dreams +Zaitsev, Alexander (2012). "Classification of interstellar radio messages". Acta Astronautica. 78: 16–19. Bibcode:2012AcAau..78...16Z. doi:10.1016/j.actaastro.2011.05.026. +Lone Signal \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Allen_Telescope_Array-0.md b/data/en.wikipedia.org/wiki/Allen_Telescope_Array-0.md new file mode 100644 index 000000000..02f353f00 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Allen_Telescope_Array-0.md @@ -0,0 +1,14 @@ +--- +title: "Allen Telescope Array" +chunk: 1/4 +source: "https://en.wikipedia.org/wiki/Allen_Telescope_Array" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:32.906338+00:00" +instance: "kb-cron" +--- + +The Allen Telescope Array (ATA), formerly known as the One Hectare Telescope (1hT), is a radio telescope array dedicated to astronomical observations and a simultaneous search for extraterrestrial intelligence (SETI). The array is situated at the Hat Creek Radio Observatory in Shasta County, 290 miles (470 km) northeast of San Francisco, California. +The project was originally developed as a joint effort between the SETI Institute and the Radio Astronomy Laboratory (RAL) at the University of California, Berkeley (UC Berkeley), with funds obtained from an initial US$12.5 million donation by the Paul G. Allen Family Foundation and Nathan Myhrvold. The first phase of construction was completed and the ATA finally became operational on 11 October 2007 with 42 antennas (ATA-42), after Paul Allen (co-founder of Microsoft) had pledged an additional $13.5 million to support the construction of the first and second phases. +Although overall Allen has contributed more than $30 million to the project, it has not succeeded in building the 350 6.1 m (20 ft) dishes originally conceived, and the project suffered an operational hiatus due to funding shortfalls between April and August 2011, after which observations resumed. Subsequently, UC Berkeley exited the project, completing divestment in April 2012. The facility is now managed by SRI International (formerly Stanford Research Institute), an independent, nonprofit research institute. As of 2016, the SETI Institute performs observations with the ATA between the hours of 6 pm and 6 am daily. +In August 2014, the installation was threatened by a forest fire in the area and was briefly forced to shut down, but ultimately emerged largely unscathed. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Allen_Telescope_Array-1.md b/data/en.wikipedia.org/wiki/Allen_Telescope_Array-1.md new file mode 100644 index 000000000..83c77b423 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Allen_Telescope_Array-1.md @@ -0,0 +1,20 @@ +--- +title: "Allen Telescope Array" +chunk: 2/4 +source: "https://en.wikipedia.org/wiki/Allen_Telescope_Array" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:32.906338+00:00" +instance: "kb-cron" +--- + +== Overview == +First conceived by SETI pioneer Frank Drake, the idea has been a dream of the SETI Institute for years. However, it was not until early 2001 that research and development began, after a donation of $11.5 million by the Paul G. Allen Family Foundation. In March 2004, following the successful completion of a three-year research and development phase, the SETI Institute unveiled a three-tier construction plan for the telescope. Construction began immediately, thanks to the pledge of $13.5 million by Paul Allen (co-founder of Microsoft) to support the construction of the first and second phases. The SETI Institute named the telescope in Allen's honor. Overall, Paul Allen contributed more than $30 million to the project. +The ATA is a centimeter-wave array which pioneers the Large-Number Small-Diameter concept of building radio telescopes. Compared to a large dish antenna, large numbers of smaller dishes are cheaper for the same collecting area. To get similar sensitivity, the signals from all telescopes must be combined. This requires high-performance electronics, which had been prohibitively expensive. Due to the declining cost of electronic components, the required electronics became practicable, resulting in a large cost-saving over telescopes of more conventional design. This is informally referred to as "replacing steel with silicon". +The ATA has four primary technical capabilities that make it well suited for a range of scientific investigations: a very wide field of view (2.45° at λ = 21 cm, the wavelength of the hydrogen line), complete instantaneous frequency coverage from 0.5 to 11.2 gigahertz (GHz), multiple simultaneous backends, and active interference mitigation. The area of sky which can be instantaneously imaged is 17 times that obtainable by the Very Large Array telescope. The instantaneous frequency coverage of more than four octaves is unprecedented in radio astronomy, and is the result of a unique feed, input amplifier and signal path design. Active interference mitigation will make it possible to observe even at the frequencies of many terrestrial radio emitters. +All-sky surveys are an important part of the science program, and the ATA will have increased efficiency through its ability to conduct extraterrestrial intelligence searches (SETI) and other radio astronomy observations simultaneously. The telescope can do this by splitting the recorded signals in the control room prior to final processing. Simultaneous observations are possible because for SETI, wherever the telescope is pointed, several target stars will lie within the large field of view afforded by the 6 m dishes. By agreement between the UC Berkeley Radio Astronomy Laboratory (RAL) and the SETI Institute, the needs of conventional radio astronomy determined the pointing of the array up until 2012. +The ATA is planned to comprise 350 6 m dishes and will make possible large, deep radio surveys that were not previously feasible. The telescope design incorporates many new features, including hydroformed antenna surfaces, a log-periodic feed covering the entire range of frequencies from 500 megahertz (MHz) to 11.2 GHz, and low-noise, wide-band amplifiers with a flat response over the entire band, thus making it possible to amplify the sky signal directly. This amplified signal, containing the entire received bandwidth, is brought from each antenna to the processing room via optical fiber cables. This means that as electronics improve and wider bandwidths are obtainable, only the central processor needs to change, and not the antennas or feeds. +The instrument was operated and maintained by RAL until development of the array was put on hold in 2011. RAL worked hand in hand with the SETI Institute during design and prototyping and was the primary designer of the feed, antenna surfaces, beamforming, correlator, and imaging system for radio astronomy observations. +The panel for the Astronomy and Astrophysics Decadal Survey in its fifth report, Astronomy and Astrophysics in the New Millennium (2001), endorsed SETI and recognized the ATA (then called the 1-Hectare Telescope) as an important stepping stone towards the building of the Square Kilometer Array telescope (SKA). The most recent Decadal report recommended ending the US's financial support of the SKA, although US participation in SKA precursors such as MeerKAT, the Hydrogen Epoch of Reionization Array and the Murchison Widefield Array. +Although cost estimates of unbuilt projects are always dubious, and the specifications are not identical (conventional telescopes have lower noise temperature, but the ATA has a larger field of view, for example), the ATA has potential promise as a much cheaper radio telescope technology for a given effective aperture. For example, the amount spent on the first ATA-42 phase, including technology development, is roughly one third of the cost of a new copy of a Deep Space Network 34 m antenna of similar collecting area. Similarly, the estimated total cost of building the remaining 308 dishes was estimated (as of October 2007) at about $41 million. This is about two times cheaper than the $85 million cost of the last large radio astronomy antenna built in the US, the Green Bank Telescope, of similar collecting area. The contractor filed for a $29 million overrun, but only $4 million of this was allowed. +The ATA aspires to be among the world's largest and fastest observing instruments, and to permit astronomers to search many different target stars simultaneously. If completed as originally envisioned, it will be one of the largest and most powerful telescopes in the world. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Allen_Telescope_Array-2.md b/data/en.wikipedia.org/wiki/Allen_Telescope_Array-2.md new file mode 100644 index 000000000..df4024d28 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Allen_Telescope_Array-2.md @@ -0,0 +1,42 @@ +--- +title: "Allen Telescope Array" +chunk: 3/4 +source: "https://en.wikipedia.org/wiki/Allen_Telescope_Array" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:32.906338+00:00" +instance: "kb-cron" +--- + +== History == +Since its inception, the ATA has been a development tool for astronomical interferometer technology (specifically, for the Square Kilometer Array). +The ATA was originally planned to be constructed in four stages, ATA-42, ATA-98, ATA-206 and ATA-350, each number representing the number of dishes in the array at a given time (See Table 1). The ATA is planned to comprise 350 dishes with a diameter of 6 m each. +Regular operations with 42 dishes started on 11 October 2007. Funding for building additional antennas is currently being sought by the SETI Institute from various sources, including the United States Navy, Defense Advanced Research Projects Agency (DARPA), National Science Foundation (NSF) and private donors. +Simultaneous astronomical and SETI observations are performed with two 32-input dual polarization imaging correlators. Numerous articles reporting conventional radio astronomy observations have been published. +Three phased array beamformers utilizing the Berkeley Emulation Engine 2 (BEE2) were deployed in June 2007 and have been integrated into the system to allow for simultaneous astronomical and SETI observations. As of April 2008, the first pulsar observations were conducted using the beamformer and a purpose-built pulsar spectrometer. +The workhorse SETI search system (SETI on ATA or SonATA) performs fully automated SETI observations. SonATA follows up on detected signals in real time and continues to track them until 1) the signal is shown to have been generated on Earth or rarely, 2) the source sets, which triggers follow up the next day. As of 2016, more than two hundred million signals have been followed up and classified using the ATA. Not one of these signals had all the characteristics expected for an ETI signal. The results of SETI Institute's observations are published in a number of papers. +In April 2011, the ATA was put into hibernation owing to funding shortfalls, meaning that it was no longer available for use. Operation of the ATA resumed on 5 December 2011. Efforts are now led by Andrew Siemion. + +=== Status === +In 2012, the ATA was funded by a $3.6 million philanthropic donation by Franklin Antonio, cofounder and Chief Scientist of Qualcomm Incorporated. This gift supports upgrades of all the receivers on the ATA dishes to have dramatically greater sensitivity (2 − 10× from 1–8 GHz) than before and support sensitive observations over a wider frequency range, from 1–15 GHz, when initially the radio frequency electronics went to only 11 GHz. By July 2016, the first ten of these receivers had been installed and proven. Full installation on all 42 antennas is planned as of June 2017. +In November 2015, the ATA studied the anomalous star KIC 8462852, and in autumn 2017 the Allen Telescope Array examined the interstellar asteroid ʻOumuamua for signs of technology, but detected no unusual radio emissions. + +== Key science goals == + +The science goals listed below represent the most important projects to be conducted with the ATA. Each of these goals is associated with one of the four stages of development mentioned earlier. (See Table 1). Also listed is some of the science that it is hoped each will produce. + +Determine the hydrogen line (HI) content of galaxies out to z ~ 0.2 over 3π steradians, in order to measure how much intergalactic gas external galaxies are accreting; to search for dark, starless galaxies; to lay the foundation for dark energy detection by the Square Kilometer Array. +Classify 250,000 extra-galactic radio sources as active galactic nuclei or starburst galaxies, in order to probe and quantify star formation in the Local Universe; to identify high redshift objects; to probe large-scale structure in the Universe; to identify gravitational lens candidates for dark matter and dark energy detection. +Explore the transient sky, in order to probe accretion onto black holes; to find orphan gamma ray burst afterglows; to discover new and unknown transient phenomena. +Survey 1,000,000 stars for SETI-related emission with enough sensitivity to detect an Arecibo radar out to 300 parsecs within the range of 1–10 GHz. +Survey the 4×1010 stars of the inner galactic plane from 1.42–1.72 GHz for very powerful transmitters. +Measure the magnetic fields in the Milky Way and other Local Group galaxies, in order to probe the role of magnetic fields in star formation and galaxy formation and evolution. +Detect the gravitational wave background from massive black holes through pulsar timing. +Measure molecular cloud and star formation properties using new molecular tracers, in order to map star formation conditions on the scale of entire giant molecular clouds (GMCs); to determine the metallicity gradient of the Milky Way. + +== Opportunistic science == +Since construction of the array began, a few science goals not specifically drawn up for it have been suggested. +For example, the Allen Telescope Array has offered to provide the mooncast data downlink for any contestants in the Google Lunar X Prize. This is practical, since the array, with no modifications, covers the main space communications bands (S-band and X-band). A telemetry decoder would be the only needed addition. +Also, the ATA was mentioned as a candidate for searching for a new type of radio transient. It is an excellent choice for this owing to its large field of view and wide instantaneous bandwidth. Following this suggestion, Andrew Siemion and an international team of astronomers and engineers developed an instrument called "Fly's Eye" that allowed the ATA to search for bright radio transients, and observations were carried out between February and April 2008. + +== Instruments == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Allen_Telescope_Array-3.md b/data/en.wikipedia.org/wiki/Allen_Telescope_Array-3.md new file mode 100644 index 000000000..f62628744 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Allen_Telescope_Array-3.md @@ -0,0 +1,152 @@ +--- +title: "Allen Telescope Array" +chunk: 4/4 +source: "https://en.wikipedia.org/wiki/Allen_Telescope_Array" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:32.906338+00:00" +instance: "kb-cron" +--- + +The ATA-42 configuration will provide a maximum baseline of 300 m (and ultimately for the ATA-350, 900 m). A cooled log-periodic feed on each antenna is designed to provide a system temperature of ~45K from 1–10 GHz, with reduced sensitivity in the ranges of 0.5–1.0 GHz and 10–11.2 GHz. Four separate frequency tunings (IFs) are available to produce 4 x 672 MHz intermediate frequency bands. Two IFs support correlators for imaging; two will support SETI observing. All tunings can produce four dual polarization phased array beams which can be independently pointed within the primary beam and can be used with a variety of detectors. The ATA can therefore synthesize up to 32 phased array beams. +The wide field of view of the ATA gives it an unparalleled capability for large surveys. The time required for mapping a large area to a given sensitivity is proportional to (ND)2, where N is the number of elements and D is the diameter of the dish. This leads to the surprising result that a large array of small dishes can outperform an array with a smaller number of elements but considerably greater collecting area in the task of large surveys. As a consequence, even the ATA-42 is competitive with much larger telescopes in its capability for both brightness temperature and point source surveys. For point source surveys, the ATA-42 is comparable in speed to Arecibo and the Green Bank Telescope (GBT), but three times slower than the Very Large Array (VLA). The ATA-350, on the other hand, will be one order of magnitude faster than the Very Large Array for point source surveys, and is comparable to the Expanded Very Large Array (EVLA) in survey speed. For surveys up to a specified brightness temperature sensitivity, the ATA-98 will exceed the survey speed of even the VLA-D configuration. The ATA-206 should match the brightness temperature sensitivity of Arecibo and the GBT. The ATA, however, provides better resolution than either of these single-dish telescopes. +The antennas for the ATA are 6.1 x 7.0 meters (20.0 ft x 23.0 ft) hydroformed offset Gregorian telescopes, each with a 2.4 meter sub-reflector with an effective focal length/diameter (f/D) ratio of 0.65. (See DeBoer, 2001). The offset geometry eliminates blockage, which increases efficiency and decreases the side lobes. It also allows for the large sub-reflector, providing good low frequency performance. The hydroforming technology used to make these surfaces is the same as that used by Andersen Manufacturing of Idaho Falls, Idaho to generate low-cost satellite reflectors. The unique interior frame rim-supported compact mount allows excellent performance at low cost. The drive system employs a spring-loaded passive anti-backlash azimuth drive train. Most components designed by Matthew Fleming and manufactured at Minex Engineering Corp. in Antioch, CA. + +== Data management == +As with other arrays, the huge amount of incoming sensory information requires real-time array processing capability in order to reduce data volume for storage. For ATA-256, the average data rates and total data volume for the correlator are estimated to be 100 Mbyte/s and 15 Pbytes for the five-year survey period. Experiments such as transient surveys will exceed this rate significantly. The beamformers produce data at a much higher rate (8 gigabytes per second (Gb/s)) but only a very small fraction of this data is archived. In 2009, the signal detection hardware and software was called Prelude, which was +composed of rack-mounted PCs augmented by two custom accelerator cards based on digital signal processing (DSP) and field-programmable gate array (FPGA) chips. Each Programmable Detection Module (one of 28 PCs) can analyze 2 MHz of dual-polarization input data to generate spectra with spectral resolution of 0.7 Hz and time samples of 1.4 seconds. +In 2009, the array had a 40 Mbit/s internet connection, adequate for remote access and transferring of data products for ATA-256. An upgrade to 40 Gbit/s was planned, which would enable direct distribution of raw data for offsite computing. + +=== Computational complexity and requirement === +Like other array systems the ATA has a computational complexity and cross-connect which scales as O(N2) with the number of antennas + + + + N + + + {\displaystyle N} + +. +The computation requirement, for example, for correlating the full ATA bandwidth ( + + + + B + + + {\displaystyle B} + + = 11 GHz) for the proposed + + + + N + + + {\displaystyle N} + + = 350 dual-polarization antenna build-out, using an efficient frequency-multiply (FX) architecture and a modest 500 kHz channel width (with number of channels + + + + F + + + {\displaystyle F} + + = 2200), is given by: + + + + + 2 + B + ⟨ + N + + log + + 2 + + + ⁡ + ( + F + ) + ( + 10 + O + P + s + ) + + + ( + N + + + + N + + + 1 + + 2 + + + ) + × + 4 + ( + 8 + O + P + s + ) + ⟩ + + + {\displaystyle 2B\langle N\log _{2}(F)(10OPs)+(N{\frac {N+1}{2}})\times 4(8OPs)\rangle } + + = 44 Peta-OPs per second +where + + + + O + p + s + + + {\displaystyle Ops} + + is an operation. Note that since each dish has a dual polarization antenna, each signal sample is actually a two data set, hence + + + + 2 + B + + + {\displaystyle 2B} + +. + +== See also == + +Carl Sagan Institute – Institute for the search of habitable worlds +Exoplanet – Planet outside of the Solar System +List of radio telescopes +SETI Institute – Not-for-profit research organization +Search for extraterrestrial intelligence – Effort to find civilizations not from Earth +setiQuest +Deep Synoptic Array, a more recent radio telescope also based on an array of smaller antennas + +== References == + +== External links == +Official website +"Radio Astronomy Laboratory's ATA site". Archived from the original on 2006-09-02. Retrieved 2015-11-16. +The Search Continues with the Allen Telescope Array. Mountain View, CA: SETI Institute. March 25, 2004. +Radio Astronomy Laboratory, University of California, Berkeley: NSF proposal, June 15, 2005. +https://web.archive.org/web/20111006031806/https://setistars.org/ +Minex Engineering Corporation in Antioch, CA \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Andrew_Fraknoi-0.md b/data/en.wikipedia.org/wiki/Andrew_Fraknoi-0.md new file mode 100644 index 000000000..eca786ecd --- /dev/null +++ b/data/en.wikipedia.org/wiki/Andrew_Fraknoi-0.md @@ -0,0 +1,25 @@ +--- +title: "Andrew Fraknoi" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Andrew_Fraknoi" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:18.390222+00:00" +instance: "kb-cron" +--- + +Andrew Fraknoi (born 1948) is a Hungarian-born American retired professor of astronomy recognized for his lifetime of work using everyday language to make astronomy more accessible and popular for both students and the general public. In 2017 Fraknoi retired from his position as Chair of the Department of Astronomy at Foothill College. In retirement he continues to teach through the Fromm Institute for Lifelong Learning and the Osher Lifelong Learning Institute at San Francisco State University, to give public lectures, and to add to his body of written work. He is the recipient of numerous awards and honors in his field. +Fraknoi continues to serve on the Board of Directors of the Search for Extraterrestrial Intelligence (SETI) Institute, a scientific and educational organization. He is also an elected Fellow of the California Academy of Sciences, an Honorary Member of the Royal Astronomical Society of Canada, and a Fellow of the Committee for Skeptical Inquiry. He has a special interest in debunking astrology and other pseudosciences connected to astronomy. + +== Early life and education == +Fraknoi was born in Hungary in 1948. Eight years later, following the Hungarian Revolution of 1956, he and his family fled their home in Budapest. They spent almost a year in an Austrian refugee camp and finally resettled in New York City. He entered his first American school at age 11, unable to speak English. Comic books, with their pictures and simple language, became his preferred entry point to learning. His initial interest was superhero comic books, and then comics with outer space themes. "This isn't just comic books – this is real," he recalls thinking about space. +Fraknoi graduated from the Bronx High School of Science in 1966. He earned his A.B. in Astronomy (with a minor in Physics) from Harvard University in 1970, and his M.A. in Astronomy from University of California, Berkeley in 1972. + +== Professional career == +Fraknoi held the position of Chair of the Department of Astronomy at Foothill College from 1992 to 2017. He also taught astronomy and physics at other institutions including San Francisco State University, City College of San Francisco, Cañada College, and several campuses of the University of California Extension Division. Fraknoi served as the executive director of the Astronomical Society of the Pacific from 1978 to 1992, edited its popular magazine "Mercury", both expanding circulation and reaching out to lay people as well as teachers. In this role he also established the newsletter "The Universe in the Classroom" specifically for teachers. He is the founder and was director of "Project ASTRO", which sets up partnerships between volunteer astronomers and 4th-9th grade teachers; each astronomer "adopts" one classroom for a year, visits at least four times, and works with the teacher to do hands-on activities in astronomy. The program is still operating in sites around the country. Later he founded and directed "Family ASTRO", a project to design activities, kits and games to help families share the excitement of astronomical discovery. +Fraknoi is recognized for both his multi-dimensional approach, and his innovation, in making astronomy more accessible to all. His popular interdisciplinary course on Albert Einstein's life and work, Physics for Poets (nicknamed "Einstein Without Tears"), won the 2005 "Innovation of the Year" award from the League for Innovation. In this course students learn about areas of modern physics that Einstein had a role in creating or changing, and then read novels, stories, and poems, and hear music influenced by Einstein's work and ideas. According to Thuy Thi Nguyen, president of Foothill College at the time of Fraknoi's retirement, the college sent a memo to the student body to warn them that spring semester 2017 would be their last chance to attend this very popular course. Fraknoi also created and offered various other courses for non-science majors. +In 2007 Fraknoi was the narrator for Gustav Holst's "The Planets" for the California Symphony Orchestra, a role he repeated with the Peninsula Symphony in 2017. He holds a long-time interest in astronomically correct science fiction, which he also uses in his teaching and writing. He has compiled an extensive resource with examples of scientifically accurate science fiction. He also is a science fiction author in his own right with twelve published stories: for example, two in the magazine Sci Phi Journal, one in the online magazine Flash Fiction, and two in science fiction anthologies. + +Since 1999, Fraknoi has organized and moderated the Silicon Valley Astronomy Lecture Series where noted astronomers from around California and the nation give nontechnical public talks on new developments in our exploration of the universe in the large Smithwick Theater at Foothill College. Cosponsored by the SETI Institute, and the Astronomical Society of the Pacific, the talks, attended by 400 to 900+ people each time, have featured Nobel laureates, members of the National Academy of Sciences, and many other distinguished scientists. Many lectures have been taped and are available on YouTube where the series has over 4 million views. +Fraknoi has served on the Board of Directors of the SETI Institute, a scientific and educational organization devoted to the search for life in the universe, since its inception in 1985. From 2010 to 2012, he was vice-chair of the Board and served on the program committee planning the first and second SETIcon, a national weekend public conferences devoted to the scientific quest for our counterparts among the stars. In 2013, he was elected to the board of trustees of the Friends of the Lick Observatory, later called the Lick Observatory Council. +In his retirement Fraknoi continues to teach classes at both the Fromm Institute for Lifelong Learning through University of San Francisco, and the Osher Lifelong Learning Institute at San Francisco State University. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Andrew_Fraknoi-1.md b/data/en.wikipedia.org/wiki/Andrew_Fraknoi-1.md new file mode 100644 index 000000000..e421d7ee3 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Andrew_Fraknoi-1.md @@ -0,0 +1,22 @@ +--- +title: "Andrew Fraknoi" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Andrew_Fraknoi" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:18.390222+00:00" +instance: "kb-cron" +--- + +== Written works == +Fraknoi is the author or co-author of 14 books in the field of astronomy. He was the lead author of Voyages through the Universe, an introductory college astronomy textbook published by Brooks-Cole, which went through three editions. In the 1980s, he co-edited with Byron Preiss two collections of science articles and science fiction stories, "The Universe" and "The Planets." With Sidney Wolff, Fraknoi founded and was co-editor of the first on-line journal devoted to astronomy education, "Astronomy Education Review". He edited two collections of resources for K-12 teachers, The Universe at Your Fingertips and More Universe at Your Fingertips published through the Astronomical Society of the Pacific. Additionally, he is the lead author of the 2016 college textbook "Astronomy", published by OpenStax as a free book for college students around the world, part of a project at Rice University (supported by the Bill and Melinda Gates Foundation and the William and Flora Hewlett Foundation) to make college more affordable. +He also authored multiple resources for young people. He is the co-author of the richly illustrated 2017 children's book about eclipses "When the Sun Goes Dark", that came out just ahead of the North American solar eclipse in August 2017. In 2007, his first children's book "Wonderful World of Space" was published by Disney. When asked about the book in a 2008 podcast interview, Fraknoi explained, "This has been a fun project. My son, who was 13 at the time, and I got a chance to write a picture book on astronomy for Disney and the challenge was how can we convey some of these modern ideas, including the Big Bang, to kids who are in 4th or 5th grade." His 2015 book, "Solar Science", published by the National Science Teachers Association, is full of 45 hands-on activities about the Sun, the seasons, the Moon, eclipses, and more. +Fraknoi frequently writes articles on interdisciplinary topics, such as using music, poetry, or science fiction to teach science. He has published a list of science fiction stories using good astronomy, as well as a resource guide to music inspired by astronomy. Fraknoi himself has had twelve science-fiction stories published. two of them in anthologies. The story "Cave in Arsia Mons" is in the book "Building Red: Mission Mars," edited by Janet Cannon, and the story "Supernova Rhythm" is published in the book "Science Fiction by Scientists," edited by Mike Brotherton and published by Springer. Two of his stories appeared in Sci Phi Journal, while others can be found on-line in Flash Fiction, Wyldblood, The Worlds Within, and Theme of Absence magazines; see External Links below. + +== Media appearances == +Fraknoi has been a frequent radio, television and podcast guest explaining astronomical developments in everyday language. According to his published biography at Wonderfest, the science education organization that awarded him their 2002 Carl Sagan Prize for Science Popularization, Fraknoi "appeared for over 20 years on the Jim Eason Show on KGO or KSFO radio and [as] a regular guest on both the Pete Wilson Show (later the "Gil Gross Show") on KGO and Michael Krasny's Forum program on KQED. Nationally, he has been heard regularly on Science Friday and Weekend All Things Considered on National Public Radio. He has given over 400 public lectures on topics ranging from the death of stars to the origin of the universe." His television appearances include The Today Show, CBS Morning News, and Larry King Live. He also posts frequently on his own blog Exploring the Universe. + +== Awards and recognition == +Fraknoi has been the recipient of many notable awards throughout his career. In 1994 he was awarded the American Astronomical Society's Annenberg Foundation Award -- then the highest honor in the field of astronomy education, as well as the Klumpke-Roberts Award of The Astronomical Society of the Pacific (given for a lifetime of contributions to popularizing astronomy). In 2002 he received the Carl Sagan Prize for Science Popularization. In 2007 he was named California Professor of the Year by the Carnegie Foundation for the Advancement of Teaching and the Council for Advancement and Support of Education. Additionally he was conferred the Astronomical Society of the Pacific's 2007 Richard H. Emmons award and the American Institute of Physics' 2007 Andrew Gemant Award (given for a lifetime of contributions to the intersection of physics and culture). In 2011 he was elected an Honorary Member by the Royal Astronomical Society of Canada and in 2013 was conferred the Faraday Science Communicator Award. Asteroid 4859 was named Asteroid Fraknoi by the International Astronomical Union "to honor his work in sharing the excitement of modern astronomy with students, teachers and the public". +In March 2019, Fraknoi was awarded the 2019 Space Educator: Lifetime Achievement Award from The National Space Club, a prestigious award that recognizes people for significant contributions to space-science education. He was presented with the award at the 62nd Annual Goddard Memorial Dinner on March 22, 2019. +He was elected a Legacy Fellow of the American Astronomical Society in 2020. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Andrew_Fraknoi-2.md b/data/en.wikipedia.org/wiki/Andrew_Fraknoi-2.md new file mode 100644 index 000000000..358740209 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Andrew_Fraknoi-2.md @@ -0,0 +1,45 @@ +--- +title: "Andrew Fraknoi" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Andrew_Fraknoi" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:18.390222+00:00" +instance: "kb-cron" +--- + +== Personal philosophy == +Fraknoi has demonstrated, through a lifetime of work, his commitment to advancing public understanding of astronomy and science using everyday language. He said in an interview after being named 2007 California Professor of the Year: "I believe that an understanding of our place in the wider universe and the methods of science are part of the birthright of everyone living on our planet.... Yet, the way science is taught in this country can often discourage non-science majors from taking a life-long interest, or even a course-long interest, in science. My philosophy is to show students that science is engaging, human, and part of our cultural heritage." In 2013 Fraknoi received the Faraday Science Communicator Award. Michael Faraday, for whom the award was named, was an influential 19th century scientist and a great advocate for rigorous, skeptical thinking and recognizing how easy it is for the mind to deceive itself. Fraknoi was quoted on receipt of the award, "I too try to encourage students and the public to examine claims at the fringes of science with skepticism and fact-based thinking". + +== Personal life == +Fraknoi and his wife live in San Francisco. They have one son. + +== Works == +Fraknoi, Andrew; Morrison, David; Wolff, Sidney (March 9, 2022). Astronomy. Houston, Texas: OpenStax and 12th Media Services. ISBN 9781680920383. +Fraknoi, Andrew; Morrison, David; Wolff, Sidney (March 11, 2005). Voyages Through the Universe (3 ed.). Belmont, CA: Brooks Cole. ISBN 978-0495017899. +Fraknoi, Andrew; Schatz, Dennis (2017). When the Sun Goes Dark. National Science Teachers Association. ISBN 978-1-68140-011-2. +Schatz, Dennis; Fraknoi, Andrew (2015). Solar Science: Exploring Sunspots, Seasons, Eclipses, and More. National Science Teachers Association Press. ISBN 978-1-941316-07-8. +Fraknoi, Andrew (3 July 2007). Space. Disney Press. ISBN 978-0-7868-4969-7. +Fraknoi, Andrew (2007). Wonderful World of Space. Disney Learning. +Fraknoi, Andrew (1985). Universe in the classroom : a resource guide for teaching astronomy and instructor's manual for Universe by William J. Kaufmann, III. New York: W.H. Freeman. ISBN 978-0716716921. +Some articles on the web by Fraknoi +Fraknoi's 2019 humorous science fiction story on a message from an extra-terrestrial civilization +Fraknoi's 2021 short science fiction story 'I Swallowed a Martian' +Fraknoi's 2022 short science fiction story 'Slow-time Station' +Fraknoi's short science fiction story 'No One Bet on Canis Major' +Fraknoi's 2025 short science fiction story 'The Lurker' +Fraknoi's 2026 short science fiction story 'Who Speaks for Earth' +Fraknoi's catalog of over 250 pieces of music inspired by astronomy +Fraknoi's annotated subject index of science fiction stories with good astronomy + +== References == + +== External links == + +Fraknoi's website +Fraknoi Facebook page +Video + +Fraknoi explaining black holes in everyday terms YouTube +Fraknoi's talk on "The 'All-American' Eclipse of the Sun" YouTube +SVAstronomyLectures YouTube channel \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-0.md b/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-0.md new file mode 100644 index 000000000..66a99716d --- /dev/null +++ b/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-0.md @@ -0,0 +1,26 @@ +--- +title: "Archaeology, Anthropology, and Interstellar Communication" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:35.284004+00:00" +instance: "kb-cron" +--- + +Archaeology, Anthropology, and Interstellar Communication is a 2014 collection of essays edited by Douglas Vakoch and published by NASA. The book is focused on the role that the humanities and social sciences, in particular anthropology and archaeology, play in the search for extraterrestrial intelligence (SETI). The seventeen essays are gathered into four sections, which respectively explore the history of SETI as a field; archaeological comparisons for human-alien communication, such as the difficulties of translating ancient languages; the inferential gap between humans and aliens, and the consequences this would have for communication and trade; and the potential nature of alien intelligences. +Originally scheduled for publication in June 2014, a PDF of Archaeology, Anthropology, and Interstellar Communication was accidentally released a month before the intended date and reviewed by Gizmodo. The positive response to the review inspired NASA to bring forward its release as an e-book, making it available on their website from May of that year. +The book gained widespread media coverage upon release. As well as receiving generally positive reviews, it was at the center of controversy regarding misinterpretation of one of its essays. A quote about ancient terrestrial stone carvings, rhetorically stating that they "might have been made by aliens" for all that they were understood by modern anthropologists, was misreported by publications such as TheBlaze, The Huffington Post, and Artnet. + +== Synopsis == +Historically, research into extraterrestrial intelligence has fallen within natural science and focused primarily on the technological obstacles to alien communication, such as processing the data encoded in signals that could be received from extraterrestrial civilizations. Archaeology, Anthropology, and Interstellar Communication was written as part of an expansion of the field to humanities and social sciences, focusing on the role archaeologists and anthropologists play in extraterrestrial intelligence research. The problems of studying ancient societies on Earth, editor Douglas Vakoch argues, are applicable to those of studying potential societies outside Earth. +Archaeology, Anthropology, and Interstellar Communication is a collection of essays exploring these roles, focusing on both historical and modern perspectives. The book consists of seventeen essays, with an introduction and epilogue by Vakoch and fifteen chapters by researchers in the relevant fields; contributing authors include John Traphagan, Albert Harrison, Ben Finney, Steven J. Dick, John Billingham, and Dominique Lestel. Issues discussed in the essays include the evolutionary and cultural prerequisites for interstellar communication, the challenges for semiotics in decoding alien signs and symbols, and the complexities of cross-cultural communication with aliens by analogy to anthropological first contact experiences. + +=== Essays === +Archaeology, Anthropology, and Interstellar Communication is subdivided into four sections, each with several essays. "Historical Perspectives on SETI" is a historiography of NASA's SETI (search for extraterrestrial intelligence) program, which ran for much of the late twentieth century before being dissolved due to lack of funding, and its humanities and social sciences representation. "Archaeological Analogues" draws comparisons between archaeology on Earth, where archaeologists frequently need to research societies they have little understanding of or shared context with, and communication with extraterrestrials. "Anthropology, Culture, and Communication" examines the role of anthropology in studying alien cultures and societies, such as the assumptions and challenges involved in cross-cultural communication and contact. "The Evolution and Embodiment of Extraterrestrials" deals with topics such as the appearance, diversity, and message design of alien intelligence. + +==== "Historical Perspectives on SETI" ==== +The essays in this section summarize the history of SETI at NASA, the circumstances that led to the government cutting public funding for SETI, and the role the social sciences have historically played in the search. The first essay in this section, "SETI: The NASA Years", is a synopsis of NASA's involvement with SETI by John Billingham, who was involved with the project from its genesis in 1969 to its closure in 1995. He discusses the 1960s origins of the search for alien life in the universe, the project's struggle to receive popular respect and government funding, and its ultimate cessation at the agency due to funding cuts, after which it was absorbed by the privately funded SETI Institute. +"A Political History of NASA's SETI Program" by Stephen J. Garber analyzes the circumstances that led to the end of public funding for the program. NASA's SETI program was small and provided few jobs that would make cutting it politically complex; widespread skepticism about the existence of intelligent alien life also made the project inherently controversial. NASA's funding also suffered through the 1990s due to publicized issues with the Hubble Space Telescope, weakening its ability to defend a marginal program such as SETI. "The Role of Anthropology in SETI: A Historical View" by Steven J. Dick discusses the history of SETI, anthropology, and their intersection. Representation of the social sciences in SETI research began during the field's early days in the 1960s and 1970s, but was, according to the essay, often tokenistic; Dick traces significant interdisciplinary work as beginning in the 1980s, with particular focus on the publication of Interstellar Migration and the Human Experience in 1986. + +==== "Archaeological Analogues" ==== \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-1.md b/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-1.md new file mode 100644 index 000000000..da07e1a7c --- /dev/null +++ b/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-1.md @@ -0,0 +1,21 @@ +--- +title: "Archaeology, Anthropology, and Interstellar Communication" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:35.284004+00:00" +instance: "kb-cron" +--- + +The essays in this section focus on the relevance of archaeological comparisons for discussing the anticipated difficulties with communication between humans and aliens. "A Tale of Two Analogues" by Ben Finney and Jerry Bentley draws on Finney's studies of Mayan culture. They draw comparisons between the protracted process of translating Mayan works and the difficulty of translating an alien work, and cast doubt on the views of some mathematicians and natural scientists that an extraterrestrial civilization would communicate with humanity solely through the "universal language" of mathematics and science. The second essay, "Beyond Linear B" by Richard Saint-Gelais, analyzes potential alien communication through a semiotic lens, commenting on the issues involved in interpreting the signs and symbols of a fundamentally different culture. He notes that the issues faced in semiotic challenges such as decoding an unknown human language may be even greater for an alien language. For instance, he describes how all known writing systems for human languages are either alphabetic, syllabic, or ideographic, and anthropologists are able to estimate which type an unknown system is by its number of characters, which may not be a shared assumption for an extraterrestrial writing system. +"Learning to Read" focuses on the hypothetical alien translation of interstellar messages transmitted by humanity. Its author Kathryn E. Denning deems the task of writing alien-translatable messages "neither trivial nor impossible", considering it a difficult task but one worthy of study; she discusses the need for interdisciplinary study to produce such messages, with important work from fields such as cryptography and anthropology. She also discusses the polarized views of natural and social sciences on the issue of alien translation, with natural scientists tending to take far more optimistic perspectives of the ease of translation than social scientists. "Inferring Intelligence" by Paul K. Wason describes the difficulty of understanding the work of prehistoric cultures and compares this difficulty to that of understanding the work of extraterrestrial cultures. He refers to the controversy regarding the meaning of Paleolithic cave art, as well as the relative recency of identifying stone tools as the intentional productions of intelligent beings. + +==== "Anthropology, Culture, and Communication" ==== +John W. Traphagan has two essays in this section, "Anthropology at a Distance" and "Culture and Communication with Extraterrestrial Intelligence". In the former, he draws comparison between the "anthropology at a distance" practice of anthropologists in the early nineteenth century, who often lacked the resources to perform fieldwork with the societies they studied, and the practice of SETI in discussing and studying uncontacted extraterrestrials. The latter focuses on the concept of hypothetical "universal languages", such as music or mathematics, and the differences human and alien cultures may have in their interpretation of these languages. +"Contact Considerations" by Douglas Raybeck considers human-alien interaction through comparison to terrestrial colonial interactions. He gives the specific examples of European contact with Aztec, Japanese, Chinese, Iroquois, and Māori cultures, all five cultures being politically and technologically complex at the time of first European contact. He discusses the likely significance of trade to human-alien interactions, both for goods and services exchanged in trade between human cultures, but potentially also for things such as music that may not exist in an alien culture. In "Speaking for Earth", Albert A. Harrison discusses the development, longevity, and potential consequences of projecting interstellar messages. He takes an optimistic position of the benevolence of extraterrestrial civilizations, referring to his own anthropological research that shows societies that endure for long periods tend to be more peaceful and less aggressive. Harrison supports Active SETI, the process of actively transmitting messages from Earth to potential interstellar societies, and discusses planned and actual attempts at it. + +==== "The Evolution and Embodiment of Extraterrestrials" ==== + +Vakoch's chapter, "The Evolution of Extraterrestrials", focuses on hypotheses of what an alien intelligence would look like, such as whether it would be humanoid or nonhumanoid. He discusses how as early as The Celestial Worlds Discover'd, published by Christiaan Huygens in 1698 and one of the first works to consider the lives of extraterrestrial beings, the possibility was raised that aliens would have similar body plans to humans (such as walking upright) but look radically different within such confines. Both arguments in favour of convergent evolution to a functionally humanoid form and divergent evolution to a radically inhuman form are summarized and considered. +"Biocultural Prerequisites for the Development of Interstellar Communication" by Garry Chick discusses the Drake equation, a means by which to estimate the number of extraterrestrial civilizations in the Milky Way galaxy capable of communicating with humans. Referring to statements by figures such as the author Michael Crichton that the parameters in the Drake equation are unknowable, and that this casts foundational doubt on the validity of SETI, Chick aims to narrow the range of possible estimates for these parameters. In "Ethology, Ethnology, and Communication with Extraterrestrial Intelligence", Lestel considers the philosophical definition of 'communication' in the context of human-alien contact. He holds that contact between terrestrial and extraterrestrial societies would have traits of both ethnology, the study of other human cultures, and ethology, the study of animal behavior. In the book's final essay, "Constraints on Message Construction for Communication with Extraterrestrial Intelligence", William H. Edmondson summarizes the issue of designing messages to be understood by extraterrestrial societies. He notes the assumptions involved in constructing interstellar messages, such as that aliens will have senses and that aspects of cognitive function (e.g. intentional behavior) will be shared between all intelligent organisms. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-2.md b/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-2.md new file mode 100644 index 000000000..377385580 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication-2.md @@ -0,0 +1,25 @@ +--- +title: "Archaeology, Anthropology, and Interstellar Communication" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:35.284004+00:00" +instance: "kb-cron" +--- + +== Publication history == +Vakoch is a professor emeritus of clinical psychology at the California Institute of Integral Studies and a self-described exo-semiotician whose research interests include psychology, comparative religion, and the philosophy of science. He is the Director of Interstellar Message Composition at the SETI Institute. In a 2002 interview with Dennis Overbye for The New York Times, he discussed his criticism of the natural sciences focus of SETI research and his work to view the subject through a humanities-focused lens, including the comparison of interstellar communication to cross-cultural interactions between terrestrial societies. One of Vakoch's goals in compiling and editing Archaeology, Anthropology, and Interstellar Communication was to highlight less optimistic perspectives on interstellar communications from such fields, addressing concerns about significant inferential gaps that had been neglected by the physical sciences. +NASA intended to publish Archaeology, Anthropology, and Interstellar Communication in both print and e-book form on 10 June 2014. On 21 May, a PDF file of the book was accidentally published on NASA's website and picked up by Gizmodo. The PDF was taken down rapidly after Gizmodo published a review, with the intention of re-releasing it on the originally intended date, but demand for copies was so high that the publication was accelerated; MOBI, EPUB, and PDF versions were officially released on 22 May and made freely available online. A paperback edition was published in September 2014 and a hardcover edition was published that December. The collection was published by NASA's History Program Office, part of the Public Outreach Division of its Office of Communications, under the NASA History Series imprint. + +== Cultural impact and reception == + +Gizmodo described Archaeology, Anthropology, and Interstellar Communication as "truly fascinating stuff" that managed to be both complex and accessible. The review began with an out-of-context quote from William Edmondson's essay on how mysterious stone carvings "might have been made by aliens" as a metaphor for the difficulties in researching long-lost ancient societies. Though it went on to note that this should not be interpreted as a literal statement, the quote was picked up by publications such as Artnet, The Blaze, and The Huffington Post as a clickbait headline. Some of these articles noted that the statement was not representative of the essay's content; others took it at face value. The aerospace analyst Jeff Foust decried the phenomenon in his review, but noted its role in highlighting how difficult even communication between human beings of similar cultures can be. +Upon the book's official release, it received mostly positive reviews. Emily Gertz, writing for Popular Science, found it "refreshing" and compared the issues it raised to those explored by science fiction works such as The Sparrow, a novel about a Jesuit priest making contact with an alien civilization. Michael Franco of CNET lauded its comprehensiveness, and Jolene Creighton, co-founder of the science news site From Quarks to Quasars, called it "a fantastic text to save for a rainy day". Writing for The Daily Dot, Aja Romano commented that the book came from a thoroughly optimistic point of view about both the existence and benevolence of extraterrestrial intelligence, but that it provided thorough investigation into SETI and had a strong understanding of the subject it investigated. Mark Anderson, Chair of the Notable Documents Panel of the American Library Association's Government Documents Round Table and research librarian at the University of Northern Colorado, reviewed Archaeology, Anthropology, and Interstellar Communication for Library Journal alongside other books published by United States government offices. He highlighted the depth of the book's scholarship and its nonetheless accessible writing. +In June 2014, weeks after the book's official release, Joshua Rothman interviewed Vakoch for The New Yorker about the struggles of extraterrestrial communication. Vakoch explained the book's purpose, discussing the integral role archaeologists and anthropologists play in extraterrestrial research. He referred to the conclusions reached by the essayists, such as Lestel's discussion of the implications involved in being unable to understand or decode potential alien messages. Vakoch described the humanities perspective on extraterrestrial communication as increasingly "skeptical and critical", but "a criticism that engages, as opposed to a criticism that dismisses". He noted that although bridging the communication gap with an extraterrestrial civilization would be a difficult ask, the rapid discovery of exoplanets in the past decades increased the likelihood extraterrestrial intelligence would be identified, making the issue more relevant. + +== References == + +== External links == + +PDF available for free download through NASA \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_Observatory-0.md b/data/en.wikipedia.org/wiki/Arecibo_Observatory-0.md new file mode 100644 index 000000000..e8ac4389e --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_Observatory-0.md @@ -0,0 +1,25 @@ +--- +title: "Arecibo Observatory" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Arecibo_Observatory" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:37.764269+00:00" +instance: "kb-cron" +--- + +The Arecibo Observatory, also known as the National Astronomy and Ionosphere Center (NAIC) and formerly known as the Arecibo Ionosphere Observatory, is an observatory in Barrio Esperanza, Arecibo, Puerto Rico, owned by the US National Science Foundation (NSF). +The observatory's main instrument was the Arecibo Telescope, a 305 m (1,000 ft) spherical reflector dish built into a natural sinkhole, with a cable-mount steerable receiver and several radar transmitters for emitting signals mounted 150 m (492 ft) above the dish. Completed in 1963, it was the world's largest single-aperture telescope for 53 years, surpassed in July 2016 by the Five-hundred-meter Aperture Spherical Telescope (FAST) in China. On August 10 and November 6, 2020, two of the receiver's support cables broke and the NSF announced that it would decommission the telescope. The telescope collapsed on December 1, 2020. In 2022, the NSF announced the telescope would not be rebuilt, with an educational facility to be established on the site. +The observatory also includes a smaller radio telescope, a LIDAR facility, and a visitor center, which remained operational after the telescope's collapse. The asteroid 4337 Arecibo was named after the observatory by Steven J. Ostro, in recognition of the observatory's contributions to the characterization of Solar System bodies. + +== History == + +In the 1950s, the United States Department of Defense (DoD) Advanced Research Projects Agency (ARPA) was seeking a means to detect missiles in Earth's ionosphere. On November 6, 1959, Cornell University entered into a contract with ARPA to carry out development studies for a large-scale ionospheric radar probe. The Arecibo Telescope was consequently built to study the ionosphere as well as to serve as a general-purpose radio telescope. Construction of the telescope was started in September 1960. The telescope and supporting observatory were formally opened as the Arecibo Ionospheric Observatory on November 1, 1963. +DoD transferred the observatory to the National Science Foundation on October 1, 1969. NSF appointed Cornell University to manage the observatory. By September 1971, NSF had renamed the observatory the National Astronomy and Ionosphere Center (NAIC) and had made it a federally funded research and development center (FFRDC). NASA began contributing funds to the observatory alongside NSF for its planetary radar mission. +In the early 2000s, NASA eliminated funding for the Arecibo Observatory. In 2006, NSF indicated that it would reduce funding for the observatory, and decommission it if other funding could not be found. Academics and politicians lobbied to stave off its closure, and NASA recommitted funding in 2011 for study of near-Earth objects. In 2011, NSF delisted Arecibo as an FFRDC, which allowed the observatory to seek funding from a wider variety of sources; the agency also replaced Cornell as the site operator with a team led by SRI International. +Damage to the telescope by 2017's Hurricane Maria led NSF again to suggest closing the observatory. A consortium led by the University of Central Florida (UCF) proposed to manage the observatory and cover much of the operations and maintenance costs, and in 2018, NSF made UCF's consortium the new site operators, though no specific actions or funding were announced. +On August 6, 2020, an auxiliary cable broke on the telescope, followed by a main cable on November 7. The NSF announced that they would decommission the telescope through controlled demolition, but that the other facilities on the observatory would remain operational. Before demolition could occur, remaining support cables from one tower rapidly failed in the morning of December 1, 2020, causing the instrument platform to crash through the dish, shearing off the tops of the support towers, and partially damaging some of the other buildings, though with no injuries. NSF officials said in 2020 that they aimed to have the other observatory facilities operational as soon as possible and were considering rebuilding a new telescope instrument in its place. However, in 2022, the NSF announced the telescope would not be rebuilt but an educational facility would be established on the site. The following year, NSF picked a consortium of universities—Cold Spring Harbor Laboratory in New York; the University of Maryland, Baltimore County; the University of Puerto Rico, Río Piedras Campus, in San Juan; and the University of the Sacred Heart, also in San Juan—to set up and run an education center called Arecibo C3 (Arecibo Center for Culturally Relevant and Inclusive Science Education, Computational Skills, and Community Engagement). + +== Facilities == + +=== Arecibo Telescope === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_Observatory-1.md b/data/en.wikipedia.org/wiki/Arecibo_Observatory-1.md new file mode 100644 index 000000000..89d2f2785 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_Observatory-1.md @@ -0,0 +1,36 @@ +--- +title: "Arecibo Observatory" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Arecibo_Observatory" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:37.764269+00:00" +instance: "kb-cron" +--- + +The observatory's main feature was its large radio telescope, the main collecting dish of which was an inverted spherical dome 1,000 feet (305 m) in diameter with an 869-foot (265 m) radius of curvature, constructed inside a karst sinkhole. The dish's surface was made of 38,778 perforated aluminum panels, each about 3 by 7 feet (1 by 2 m), supported by a mesh of steel cables. The ground beneath supported shade-tolerant vegetation. +Since its completion in November 1963, the Telescope had been used for radar astronomy and radio astronomy, and had been part of the Search for extraterrestrial intelligence (SETI) program. It was also used by NASA for Near-Earth object detection. Since around 2006, NSF funding support for the telescope had waned as the Foundation directed funds to newer instruments, though academics petitioned to the NSF and Congress to continue support for the telescope. Numerous hurricanes, including Hurricane Maria, had damaged parts of the telescope, straining the reduced budget. +Two cable breaks, one in August 2020 and a second in November 2020, threatened the structural integrity of the support structure for the suspended platform and damaged the dish. The NSF determined in November 2020 that it was safer to decommission the telescope rather than to try to repair it, but the telescope collapsed before a controlled demolition could be carried out. The remaining support cables from one tower failed around 7:56 a.m. local time on December 1, 2020, causing the receiver platform to fall into the dish and collapsing the telescope. +NASA led an extensive failure investigation and reported the findings, along with a technical bulletin with industry recommendations. The investigation concluded that "a combination of low socket design margin and a high percentage of sustained loading revealed an unexpected vulnerability to zinc creep and environments, resulting in long-term cumulative damage and progressive zinc/wire failure". +In 2024, the National Academies of Science, Engineering, and Medicine published their definitive report, "Failure Analysis of the Arecibo Observatory 305-Meter Telescope Collapse". The report cited many of the previous reports and findings, including the role of the high-energy output interacting with the zinc wire rope "brooming". It also raised the issue of the original design standards available in the 1980s versus the later advances in wind load engineering. + +=== Additional telescopes === +The Arecibo Observatory also has other facilities beyond the main telescope, including a 12-meter (39 ft) radio telescope intended for very-long-baseline interferometry (VLBI) with the main telescope; and a LIDAR facility whose research has continued since the main telescope's collapse. + +=== Ángel Ramos Foundation Visitor Center === + +Opened in 1997, the Ángel Ramos Foundation Visitor Center features interactive exhibits and displays about the operations of the radio telescope, astronomy and atmospheric sciences. The center is named after the financial foundation that honors Ángel Ramos, owner of the El Mundo newspaper and founder of Telemundo. The Foundation provided half of the funds to build the Visitor Center, with the remainder received from private donations and Cornell University. +The center, in collaboration with the Caribbean Astronomical Society, hosts a series of Astronomical Nights throughout the year, which feature diverse discussions regarding exoplanets, astronomical phenomena, and discoveries (such as Comet ISON). The purposes of the center are to increase public interest in astronomy, the observatory's research successes, and space endeavors. + +== List of directors == +Source(s): + +== See also == + +== References == + +== Further reading == + +== External links == + +Official website \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_Telescope-0.md b/data/en.wikipedia.org/wiki/Arecibo_Telescope-0.md new file mode 100644 index 000000000..47d7daeaa --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_Telescope-0.md @@ -0,0 +1,25 @@ +--- +title: "Arecibo Telescope" +chunk: 1/6 +source: "https://en.wikipedia.org/wiki/Arecibo_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:38.928164+00:00" +instance: "kb-cron" +--- + +The Arecibo Telescope was a 305 m (1,000 ft) spherical reflector radio telescope built into a natural sinkhole at the Arecibo Observatory located near Arecibo, Puerto Rico. A cable-mounted, steerable receiver and several radar transmitters for emitting signals were mounted 150 m (492 ft) above the dish. Completed in November 1963, the Arecibo Telescope was the world's largest single-aperture telescope for 53 years, until it was surpassed in July 2016 by the Five-hundred-meter Aperture Spherical Telescope (FAST) in Guizhou, China. Decommissioning the Arecibo Telescope was announced in November 2020, and the telescope collapsed in December 2020. +The Arecibo Telescope was primarily used for research in radio astronomy, atmospheric science, and radar astronomy, as well as for programs that search for extraterrestrial intelligence (SETI). Scientists wanting to use the observatory submitted proposals that were evaluated by independent scientific referees. NASA also used the telescope for near-Earth object detection programs. The observatory, funded primarily by the National Science Foundation (NSF) with partial support from NASA, was managed by Cornell University from its completion in 1963 until 2011, after which it was transferred to a partnership led by SRI International. In 2018, a consortium led by the University of Central Florida assumed operation of the facility. +The telescope's unique and futuristic design led to several appearances in film, gaming and television productions, such as for the climactic fight scene in the James Bond film GoldenEye (1995). It is one of the 116 pictures included in the Voyager Golden Record. It has been listed on the US National Register of Historic Places since 2008. The telescope was named an IEEE Milestone in 2001. +The NSF reduced its funding commitment to the observatory from 2006, leading academics to push for additional funding support to continue its programs. The telescope was damaged by Hurricane Maria in 2017 and was affected by earthquakes in 2019 and 2020. Two cable breaks, one in August 2020 and a second in November 2020, threatened the structural integrity of the support structure for the suspended platform and damaged the dish. Due to uncertainty over the remaining strength of the other cables supporting the suspended structure, and the risk of collapse owing to further failures making repairs dangerous, the NSF announced on November 19, 2020, that the telescope would be decommissioned and dismantled, with the LIDAR facility remaining operational. Before it could be decommissioned, several of the remaining support cables suffered a critical failure and the support structure, antenna, and dome assembly all fell into the dish at 7:55 a.m. local time on December 1, 2020, destroying the telescope. The NSF decided in October 2022 that it would not rebuild the telescope or build a similar observatory at the site. + +== General information == + +The telescope's main collecting dish had the shape of a spherical cap 305 metres (1,000 ft) in diameter with an 265-metre (870 ft) radius of curvature, and was constructed inside a karst sinkhole. The dish surface was made of 38,778 perforated aluminum panels, each about 1 by 2 metres (3 by 7 ft), supported by a mesh of steel cables. The ground beneath supported shade-tolerant vegetation. +The telescope had three radar transmitters, with effective isotropic radiated powers (EIRPs) of 22 TW (continuous) at 2380 MHz, 3.2 TW (pulse peak) at 430 MHz, and 200 MW at 47 MHz, as well as an ionospheric modification facility operating at 5.1 and 8.175 MHz. +The dish remained stationary, while receivers and transmitters were moved to the proper focal point of the telescope to aim at the desired target. As a spherical mirror, the reflector's focus was along a line rather than at one point. As a result, complex line feeds were implemented to carry out observations, with each line feed covering a narrow frequency band measuring 10–45 MHz. A limited number of line feeds could be used at any one time, limiting the telescope's flexibility. +The receiver was on an 820-tonne (900-short-ton) platform suspended 150 m (492 ft) above the dish by 18 main cables running from three reinforced concrete towers (six cables per tower), one 111 m (365 ft) high and the other two 81 m (265 ft) high, placing their tops at the same elevation. Each main cable was a 8 cm (3.1 in) diameter bundle containing 160 wires, with the bundle painted over and dry air continuously blown through to prevent corrosion due to the humid tropic climate. The platform had a rotating, bow-shaped track 93 m (305 ft) long, called the azimuth arm, carrying the receiving antennas and secondary and tertiary reflectors. This allowed the telescope to observe any region of the sky in a forty-degree cone of visibility about the local zenith (between −1 and 38 degrees of declination). Puerto Rico's location near the Northern Tropic allowed the Arecibo telescope to view the planets in the Solar System over the northern half of their orbit. The round trip light time to objects beyond Saturn is longer than the 2.6-hour time that the telescope could track a celestial position, preventing radar observations of more distant objects. + +== History == + +=== Design and construction === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_Telescope-1.md b/data/en.wikipedia.org/wiki/Arecibo_Telescope-1.md new file mode 100644 index 000000000..6f6ab96dd --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_Telescope-1.md @@ -0,0 +1,19 @@ +--- +title: "Arecibo Telescope" +chunk: 2/6 +source: "https://en.wikipedia.org/wiki/Arecibo_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:38.928164+00:00" +instance: "kb-cron" +--- + +The origins of the observatory trace to late 1950s efforts to develop anti-ballistic missile (ABM) defenses as part of the newly formed United States Department of Defense (DoD) Advanced Research Projects Agency (ARPA) ABM umbrella-effort, Project Defender. Even at this early stage it was clear that the use of radar decoys would be a serious problem at the long ranges needed to successfully attack a warhead, ranges on the order of 1,600 km (1,000 miles). +Among the many Defender projects were several studies based on the concept that a re-entering nuclear warhead would cause unique physical signatures while still in the upper atmosphere. It was known that hot, high-speed objects caused ionization of the atmosphere that reflects radar waves, and it appeared that a warhead's signature would be different enough from decoys that a detector could pick out the warhead directly, or alternately, provide added information that would allow operators to focus a conventional tracking radar on the single return from the warhead. +Although the concept appeared to offer a solution to the tracking problem, there was almost no information on either the physics of re-entry or a strong understanding of the normal composition of the upper layers of the ionosphere. ARPA began to address both simultaneously. To better understand the radar returns from a warhead, several radars were built on Kwajalein Atoll, while Arecibo started with the dual purpose of understanding the ionosphere's F-layer while also producing a general-purpose scientific radio observatory. +On November 6, 1959, Cornell University entered into a contract with ARPA to carry out development studies for a large-scale ionospheric radar probe, exploring how this instrument could also be utilized in radio astronomy and other scientific areas. The observatory was built between mid-1960 and November 1963. William E. Gordon and George Peter of Cornell University oversaw its design for study of the Earth's ionosphere. He was attracted to the sinkholes in the karst regions of Puerto Rico that offered perfect cavities for a very large dish. Originally, a fixed parabolic reflector was envisioned, pointing in a fixed direction with a 150 m (492 ft) tower to hold equipment at the focus. This design would have limited its use in other research areas, such as radar astronomy, radio astronomy and atmospheric science, which require the ability to point at different positions in the sky and track those positions for an extended time as the Earth rotates. +Ward Low of the ARPA pointed out this flaw and put Gordon in touch with the Air Force Cambridge Research Laboratory (AFCRL) in Boston, Massachusetts, where one group headed by Phil Blacksmith was working on spherical reflectors and another group was studying the propagation of radio waves in and through the upper atmosphere. Cornell University proposed the project to ARPA in mid-1958 and a contract was signed between the AFCRL and the University in November 1959. Cornell University and Zachary Sears published a request for proposals (RFP) asking for a design to support a feed moving along a spherical surface 133 metres (435 ft) above the stationary reflector. The RFP suggested a tripod or a tower in the center to support the feed. On the day the project for the design and construction of the antenna was announced at Cornell University, Gordon had also envisioned a 133 m (435 ft) tower centered in the 305 m (1,000 ft) reflector to support the feed. +George Doundoulakis, who directed research at the General Bronze Corporation in Garden City, New York, along with Zachary Sears, who directed Internal Design at Digital B & E Corporation, New York, received the RFP from Cornell University for the antenna design and studied the idea of suspending the feed with his brother, Helias Doundoulakis, a civil engineer. George Doundoulakis identified the problem that a tower or tripod would have presented around the center, (the most important area of the reflector), and devised a better design by suspending the feed. He presented his proposal to Cornell University for a doughnut or torus-type truss suspended by four cables from four towers above the reflector, having along its edge a rail track for the azimuthal truss positioning. This second truss, in the form of an arc, or arch, was to be suspended below, which would rotate on the rails through 360 degrees. The arc also had rails on which the unit supporting the feed would move for the feed's elevational positioning. A counterweight would move symmetrically opposite to the feed for stability and, if a hurricane struck, the whole feed could be raised and lowered. Helias Doundoulakis designed the cable suspension system which was finally adopted. The final configuration was substantially the same as in the original drawings by George and Helias Doundoulakis, although with three towers, instead of the four drawn in the patent, which was granted to Helias Doundoulakis by the U.S. Patent office. +The suspended structure was designed by Dr. Thomas C. Kavanagh, Fred Severud, and Dr. Hans Bandel, who were selected after the 1959 RFP issued by Cornell University. A proposal by the General Bronze Corporation was not selected as it did not meet specifications, according to an editorial response by Donald Cooke (Cornell's spokesperson) to Helias Doundoulakis in a newsletter of the Institute of Electrical and Electronics Engineers (IEEE). Cooke stated that Doundoulakis used an incorrect feed/paraxial surface measurement. However, the measurement Cooke used was from Doundoulakis’ patent issued in 1966, and not from the 1959 RFP meetings which predated the patent by seven years. Furthermore, proposal measurements presented by George Doundoulakis and Helias Doundoulakis at the RFP meeting on December 10, 1959, were not referenced in Cooke's editorial response. The originators of this proposal subsequently filed a dispute, originally for $1.2 million but was settled for $10,000 because "the defense in a court trial would cost far more than the $10,000 for which the case was settled," and accordingly, on April 11, 1975, Doundoulakis v. U.S. (Case 412-72) had been ruled in plaintiff's favor by the United States Court of Federal Claims, that “(a) a judgment has been entered in favor of the plaintiffs (Helias Doundoulakis, William J. Casey, and Constantine Michalos) against the United States and (b) in consideration of the sum of $10,000 to be paid by the United States Government to the plaintiff, the plaintiffs grants to the United States Government an irrevocable, fully-paid, non-exclusive license under the aforesaid U.S. Patent No. 3, 273, 156 to Cornell University.” +The idea of a spherical reflecting mirror with a steerable secondary has since been used in optical telescopes, in particular, the Hobby–Eberly Telescope +Construction began in mid-1960, with the telescope operational about three years later. The telescope's and the supporting observatory's official opening as the Arecibo Ionospheric Observatory (AIO) was held on November 1, 1963. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_Telescope-2.md b/data/en.wikipedia.org/wiki/Arecibo_Telescope-2.md new file mode 100644 index 000000000..e723c4761 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_Telescope-2.md @@ -0,0 +1,25 @@ +--- +title: "Arecibo Telescope" +chunk: 3/6 +source: "https://en.wikipedia.org/wiki/Arecibo_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:38.928164+00:00" +instance: "kb-cron" +--- + +=== Upgrades === +Since its construction, the telescope was upgraded several times, following the facility's oversight from the DoD to the National Science Foundation on October 1, 1969, and subsequent renaming of the AIO to the National Astronomy and Ionosphere Center (NAIC) in September 1971. +Initially, when the maximum expected operating frequency was about 500 MHz, the surface consisted of half-inch galvanized wire mesh laid directly on the support cables. In 1973, a high-precision surface consisting of 38,000 individually adjustable aluminum panels replaced the old wire mesh, and the highest usable frequency rose to about 5000 MHz. +A Gregorian reflector system was installed in 1997, incorporating secondary and tertiary reflectors to focus radio waves to one point. This allowed installing a suite of receivers, covering the full 1–10 GHz range, that could be easily moved to the focal point, giving Arecibo more flexibility. The additional instrumentation added 270 tonnes (300 short tons) to the platform, so six additional support cables were added, two for each tower. A metal mesh screen was also installed around the perimeter to block the ground's thermal radiation from reaching the feed antennas. As part of this upgrade, the power of the 2380 MHz transmitter was doubled to 1 MW by adding a second Klystron tube and improving the design. +Finally, in 2013 with a grant of US$2.5 million, work for adding the ionospheric modification HF facility began, which was completed in 2015. The HF facility consisted, on the sender side, of six foldable 100 kW crossed dipoles inside the main dish, and a hanging 100m-wide subreflector mesh between the dish and the platform. + +=== Funding reductions === +The Astronomical Sciences and Atmospheric Sciences divisions of the NSF had financially supported Arecibo since its completion in the 1970s, with incremental support by NASA, for operating the planetary radar. In 2001 NASA announced a rampdown and elimination of its support of the planetary radar by 2005. +In 2002, after several years of discussion, the US Congress passed a bill to double the NSF budget, and instructed the NSF to begin new projects. As a result, the NSF began committing to major projects. However, the funding increase never arrived and the NSF was left with the new commitments. In 2005 the Astronomical Sciences division commissioned a "Senior Review" of its facilities to deal with its increasingly constrained budget. The Senior Review report released in November 2006 "regretfully" recommended substantially decreased astronomy funding for the Arecibo Observatory, beginning with a cut to US$10.5 million in 2007 and continuing to decrease to US$4.0 million in 2011. The report further stated that if other sources of funding could not be found, closure of the Observatory was recommended. +Academics and researchers responded by organizing to protect and advocate for the observatory. They established the Arecibo Science Advocacy Partnership (ASAP) in 2008, to advance the scientific excellence of Arecibo Observatory research and to publicize its accomplishments in astronomy, aeronomy and planetary radar as to seek additional funding support for the observatory. An additional US$3 million in bonds were issued by the government of Puerto Rico to fund the Observatory, which were used to modernize power generation and improve other aging infrastructure. Academics, media and influential politicians pressured the United States Congress on the importance of the work of the observatory. led to additional US$3.1 million in funding to support Arecibo in the American Recovery and Reinvestment Act of 2009. This was used for basic maintenance and for a second, much smaller, antenna to be used for very long baseline interferometry, new Klystron amplifiers for the planetary radar system and student training. +Arecibo's budget from NSF continued to wane in the following years. Starting in FY2010, NASA restored its historical support by contributing $2.0 million per year for planetary science, particularly the study of near-Earth objects, at Arecibo. NASA implemented this funding through its Near Earth Object Observations program. NASA increased its support to $3.5 million per year in 2012. +In 2011, NSF removed Cornell University, which had managed the National Astronomy and Ionosphere Center (NAIC) since the 1970s, as the operator and transferred these responsibilities to SRI International, along with two other managing partners, Universities Space Research Association and Universidad Metropolitana de Puerto Rico, with a number of other collaborators. NSF also decertified NAIC as a Federally Funded Research and Development Center (FFRDC), which the NSF said would give NAIC greater freedom to establish broader scientific partnerships and pursue funding opportunities for activities beyond the scope of those supported by NSF, but which would also remove the FFRDC's promise of stability intended to retain the very best technical staff. +While the Observatory continued to operate under the reduced NSF budget and NASA funds, NSF signaled in 2015 and 2016 that it was looking towards potential decommissioning of the Observatory by initiating environmental impact statements on the effect of disassembling the unit. The NSF continued to indicate it would like to reduce funding to the Observatory in the short term. As in 2008, academics expressed their concern over the loss of scientific discoveries that could occur should the Observatory be shut down. + +=== 2020 damage, decommissioning plans, and collapse === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_Telescope-3.md b/data/en.wikipedia.org/wiki/Arecibo_Telescope-3.md new file mode 100644 index 000000000..f45cc0084 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_Telescope-3.md @@ -0,0 +1,16 @@ +--- +title: "Arecibo Telescope" +chunk: 4/6 +source: "https://en.wikipedia.org/wiki/Arecibo_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:38.928164+00:00" +instance: "kb-cron" +--- + +Several hurricanes and storms over the 2010s had raised the concerns of structural engineers over the stability of the observatory. On September 21, 2017, high winds associated with Hurricane Maria caused the 430 MHz line feed to break and fall onto the primary dish, damaging roughly 30 of the 38,000 aluminum panels. Most Arecibo observations did not use the line feed but instead relied on the feeds and receivers located in the dome. Overall, the damage inflicted by Maria was minimal, but it further clouded the observatory's future. Restoring all the previous capabilities required more than the observatory's already-threatened operating budget, and users feared that the decision would be made to decommission it instead. +A consortium consisting of the University of Central Florida (UCF), Yang Enterprises and UMET came forward to supply funding in February 2018 to allow the NSF to reduce its contribution towards Arecibo's operating costs from $8 million to $2 million from the fiscal year 2022–2023, thus securing the observatory's future. With this, the UCF consortium were named the new operators of the observatory in 2018. +On August 10, 2020, an auxiliary platform support cable separated from Tower 4, causing damage to the telescope, including a 30 meters (100 ft) gash in the reflector dish. Damage included six to eight panels in the Gregorian dome, and to the platform used to access the dome. No one was reported to have been hurt by the partial collapse. The facility was closed as damage assessments were made. +The facility had recently reopened following the passing of Tropical Storm Isaias. It was unclear if the cable failure was caused by Isaias. Former Arecibo Observatory director Robert Kerr stated that prior to the 1997 installation of the Gregorian dome, the main support cables and support towers had been engineered with a safety factor of two, as to be able to sustain twice the weight of the platform. When the dome was added in 1997, the auxiliary cables were intended to retain the safety factor of two once all design factors were considered, but Kerr believed that that was never the case, as evenly distributing the loads following that install would be difficult to do. Kerr also stated that there had been periods of neglect at the Observatory, during which the fans that were used to blow dry air along the wire bundles were not operating. The earlier storms would have brought seawater to the cables, which could accelerate the rate of corrosion as well, according to Kerr. Engineering firms hired by UCF inspected the socket area where the cable had failed, and found a similar problem that had been observed in the 1980s during a routine cable replacement, in which the use of molten zinc to affix the cable to the socket mount at the tower was not complete, allowing moisture to get into the wire bundle and cause corrosion, and leading to the cable slipping from its socket. The firms had developed models of the telescope that showed that the safety factor for Tower 4 had dropped to 1.67, believing that the structure was still safe while repairs could be effected, even if another cable collapsed. Plans were made to replace all six auxiliary cables since their socket welds were all considered suspect, at a cost of US$10.5 million. +Before repairs could be started, on November 7, 2020, one of the two main support cables from Tower 4 snapped, shattering part of the dish itself as it fell. The UCF engineering staff, which had been monitoring the cables with support from the U.S. Army Corps of Engineers, and the engineering firms they had hired previously evaluated the remaining cables from Tower 4. One engineering firm proposed stabilization efforts, while another suggested that they try to sever parts of the instrument platform such as the Gregorian dome to reduce the load. The third firm made the determination that there was no way to safely repair the damage at that point, as the remaining cables could be suspect, and furthermore that a controlled decommissioning of the telescope was the only effective means to avoid catastrophic failure which would threaten the other buildings on campus. The NSF took this advice and made the announcement on November 19, 2020, that they would decommission Arecibo over the following few weeks after determining the safest route to do so, with a safety exclusion zone immediately put in place. NSF's Sean Jones stated, "This decision is not an easy one for NSF to make, but safety of people is our number one priority." The lidar facility was to remain operational. +While waiting for NSF to make the decommissioning plans, steps had been taken to try to reduce the load that each of the towers was carrying, including reducing the strain on the backstay support cables for the individual towers. Other plans, such as having helicopters hoisting part of the load while hovering above the telescope, were proposed but deemed too risky. Engineers from UCF had been monitoring the telescope and observed that wires in the backstay cables for the support towers had been breaking at a rate of one or two a day, and estimated that the telescope would soon collapse. In the weekend prior to December 1, 2020, wire strands in the receiver's supporting cables had also been snapping apart at a rapid rate, according to Ángel Vázquez, the director of operations. This culminated in the collapse of the receiver platform at around 6:55 a.m. AST (10:55 UTC) on December 1, 2020, as the second main cable from Tower 4 failed, with the other two remaining support cables failing moments later. The collapse of the receiver structure and cables onto the dish caused extensive additional damage. As the receiver fell, it also sheared the tips of the towers which the support cables ran through. Once the main cables from Tower 4 released, the backstay cables, which normally balanced the horizontal component of force from the main cables, pulled the tower outwards and broke off the top. The other two towers, once the force of supporting the platform was released, also had their tips sheared off due to the backstay cable tension. The top of Tower 12 caused some structural damage to other buildings on the observatory as it fell. No injuries from the collapse were reported. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_Telescope-4.md b/data/en.wikipedia.org/wiki/Arecibo_Telescope-4.md new file mode 100644 index 000000000..798193553 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_Telescope-4.md @@ -0,0 +1,30 @@ +--- +title: "Arecibo Telescope" +chunk: 5/6 +source: "https://en.wikipedia.org/wiki/Arecibo_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:38.928164+00:00" +instance: "kb-cron" +--- + +=== Post-collapse === + +In the weeks following Arecibo's collapse, the administration of the Five-hundred-metre Aperture Spherical Telescope (FAST) in China, which had drawn some design principles from Arecibo, stated that they would start taking applications for international researchers to use the telescope starting in 2021. +In late December 2020, Wanda Vázquez Garced, then governor of Puerto Rico signed an executive order for $8 million for the removal of debris and for the design of a new observatory to be built in its place. The governor stated reconstruction of the observatory is a "matter of public policy". The executive order also designated the area as a history site. +As required by the Consolidated Appropriations Act, 2021, the NSF sent a report to Congress in March 2022 "on the causes and extent of the damage, the plan to remove debris in a safe and environmentally sound way, the preservation of the associated [Arecibo Observatory] facilities and surrounding areas, and the process for determining whether to establish comparable technology at the site, along with any associated cost estimates". On March 25, 2022, a survey salvage committee formed by UCF and the NSF issued a final report, identifying materials from the site that may be salvaged for their "historic importance or scientific utility." +A team from the University of Texas at Austin was able to completely recover and back up the 3 petabytes of data that the telescope had captured since opening in the 1960s by May 2021 before further harm could come to the storage equipment. The data was relocated to the school's servers at the Texas Advanced Computing Center to be made available for continued research. +An early plan developed by NSF scientists suggest one possible replacement called the Next Generation Arecibo Telescope, using 1000 closely-packed 9-meter (30 ft) telescopes mounted on one or more flat plate(s) that would cover the 300-meter (980 ft) width of the Arecibo sinkhole. While the telescopes themselves would be fixed, the plate(s) would be able to be rotated more than 45° off the horizontal in any direction. This would allow the new instrument to have 500 times the field of view of the original Arecibo Telescope, and be twice as sensitive with four times the radar power. It was expected this would cost roughly US$450 million to build. This would enable better study of the supermassive black hole at the center of the Milky Way as a prime target. +NSF decided in October 2022 that the Arecibo site would not be used for a new telescope, instead converting the site to be a STEM educational center. +The Arecibo Salvage Survey committee preserved some parts of the telescope, including parts of the zenith and azimuth tracks, a corner of the platform, the rotary joint, and the cable car. +In 2024 the National Academies of Sciences, Engineering and Medicine issued a report on the collapse. The report cited many of the previous reports and findings, including the role of the high-energy output interacting with the zinc wire rope "booming". Issues of redundancy, a typical engineering principle, was raised since there was no provision for major overhauls. The report also discussed the organizational issues of transfer of knowledge over time regarding various long term maintenance issues. It also raised the issue of the original engineering safety standards available in the 1980s versus the later advances in wind load engineering. + +== Research and discoveries == + +Many scientific discoveries were made with the observatory. On April 7, 1964, soon after it began operating, Gordon Pettengill's team used it to determine that the rotation period of Mercury was not 88 days, as formerly thought, but only 59 days. In 1968, the discovery of the periodicity of the Crab Pulsar (33 milliseconds) by Richard V. E. Lovelace and others provided the first solid evidence that neutron stars exist. In 1974, Hulse and Taylor discovered the first binary pulsar PSR B1913+16, an accomplishment for which they later received the Nobel Prize in Physics. In 1982, the first millisecond pulsar, PSR B1937+21, was discovered by Donald C. Backer, Shrinivas Kulkarni, Carl Heiles, Michael Davis, and Miller Goss. This object spins 642 times per second and, until the discovery of PSR J1748-2446ad in 2005, was identified as the fastest-spinning pulsar. +In 1980, Arecibo made the first radar observation of a comet when it successfully detected Comet Encke. In July 1985, the observatory obtained the first two-dimensional image of an asteroid, 1627 Ivar. +In August 1989, radar observations of near-Earth asteroid 4769 Castalia yielded a sequence of delay–Doppler images showing two lobes in contact, providing the first observation of a contact binary. The following year, Polish astronomer Aleksander Wolszczan made the discovery of pulsar PSR B1257+12 (Lich), which later led him to discover its three orbiting planets. These were the first extrasolar planets discovered. In 1994, John Harmon used the Arecibo Radio Telescope to map the distribution of ice in the polar regions of Mercury. +In January 2008, detection of prebiotic molecules methanimine and hydrogen cyanide were reported from the observatory's radio spectroscopy measurements of the distant starburst galaxy Arp 220. +From January 2010 to February 2011, astronomers Matthew Route and Aleksander Wolszczan detected bursts of radio emission from the T6.5 brown dwarf 2MASS J10475385+2124234. This was the first time that radio emission had been detected from a T dwarf, which has methane absorption lines in its atmosphere. It is also the coolest brown dwarf (at a temperature of ~900K) from which radio emission has been observed. The highly polarized and highly energetic radio bursts indicated that the object has a >1.7 kG-strength magnetic field and magnetic activity similar to both the planet Jupiter and the Sun. + +=== The Arecibo message === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_Telescope-5.md b/data/en.wikipedia.org/wiki/Arecibo_Telescope-5.md new file mode 100644 index 000000000..1964f2825 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_Telescope-5.md @@ -0,0 +1,49 @@ +--- +title: "Arecibo Telescope" +chunk: 6/6 +source: "https://en.wikipedia.org/wiki/Arecibo_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:38.928164+00:00" +instance: "kb-cron" +--- + +In 1974, the Arecibo message, an attempt to communicate with potential extraterrestrial life, was transmitted from the radio telescope toward the globular cluster Messier 13, about 25,000 light-years away. The 1,679 bit pattern of 1s and 0s defined a 23 by 73 pixel bitmap image that included numbers, stick figures, chemical formulas and a crude image of the telescope. + +=== SETI and METI projects === + +Search for extraterrestrial intelligence (SETI) is the search for extraterrestrial life or advanced technologies. SETI aims to answer the question "Are we alone in the Universe?" by scanning the skies for transmissions from intelligent civilizations elsewhere in our galaxy. +In comparison, METI (messaging to extraterrestrial intelligence) refers to the active search by transmitting messages. +Arecibo was the source of data for the SETI@home and Astropulse distributed computing projects put forward by the Space Sciences Laboratory at the University of California, Berkeley, and was used for the SETI Institute's Project Phoenix observations. The Einstein@Home distributed computing project has found more than 20 pulsars in Arecibo data. + +=== Other uses === +Terrestrial aeronomy experiments at Arecibo included the Coqui 2 experiment, supported by NASA. The telescope also originally had military intelligence uses, including locating Soviet radar installations by detecting their signals bouncing off the Moon. +Limited amateur radio operations were carried out, using Moon bounce or Earth–Moon–Earth communication, in which radio signals aimed at the Moon are reflected back to Earth. The first of these operations was on June 13–14, 1964, using the call sign KP4BPZ. A dozen or so two-way contacts were made on 144 and 432 MHz. On July 3 and 24, 1965, KP4BPZ was again activated on 432 MHz, making approximately 30 contacts on 432 MHz during the limited time slots available. For these tests, a very wide-band instrumentation recorder captured a large segment of the receiving bandwidth, enabling later verification of other amateur station call signs. These were not two-way contacts. From April 16–18, 2010, the Arecibo Amateur Radio Club KP4AO again conducted Moon-bounce activity using the antenna. On November 10, 2013, the KP4AO Arecibo Amateur Radio Club conducted a Fifty-Year Commemoration Activation, lasting seven hours on 14.250 MHz SSB, without using the main dish antenna. + +== Cultural significance == +Due to its unique shape and concept, the telescope had been featured in many contemporary works. It serves as one of the central locations in The Sparrow, a science fiction novel written by Mary Doria Russell. It was used as a filming location in the films GoldenEye (1995), Species (1995), and Contact (1997) (based on Carl Sagan's novel of the same name, which also featured the observatory), The Losers (2010), , as the climatic battleground against Ultron in Season 3 of ’’Avengers Assemble’’and in The X-Files television episode "Little Green Men". One map in the 2013 video game Battlefield 4, while set in China, is based on the distinctive layout of the Arecibo Telescope. In 2014, a video art installation piece titled The Great Silence by artists Jennifer Allora and Guillermo Calzadilla in collaboration with science fiction writer Ted Chiang featured the radio telescope at Arecibo Observatory to represent the search for extraterrestrial life. The next year, Chiang published a novelette also called The Great Silence. The juxtaposed text was later published as a short story with the same title in a special issue of the art journal e-flux in 2015 and was included in the author's short story collection Exhalation: Stories in 2019. +The asteroid 4337 Arecibo is named after the observatory by Steven J. Ostro, in recognition of the observatory's contributions to the characterization of Solar System bodies. + +== See also == +List of radio telescopes +Lunar Crater Radio Telescope - a proposed project by NIAC to place a radio telescope on the far side of the Moon +Orgov Radio-Optical Telescope + +== References == + +== Further reading == +Friedlander, Blaine (November 14, 1997). "Research rockets, including an experiment from Cornell, are scheduled for launch into the ionosphere next year from Puerto Rico". Cornell University. +Ruiz, Carmelo (March 3, 1998). "Activists protest US Navy radar project". Global Network Against Weapons and Nuclear Power in Space. Archived from the original on May 1, 2001. +Amir Alexander (July 3, 2008). "Budget Cuts Threaten Arecibo Observatory". The Planetary Society. Archived from the original on July 21, 2008. +Blaine Friedlander (June 10, 2008). "Arecibo joins global network to create 6,000-mile (9,700 km) telescope". EurekAlert. +Lauren Gold (June 5, 2008). "Clintons (minus Hillary) visit Arecibo; former president urges more federal funding for basic sciences". Cornell university. +Henry Fountain (December 25, 2007). "Arecibo Radio Telescope Is Back in Business After 6-Month Spruce-Up". New York Times. +Entry into the National Register of Historic Places +Cohen, Marshall H. (2009). "Genesis of the 1000-foot Arecibo Dish". Journal of Astronomical History and Heritage. 12 (2): 141–152. Bibcode:2009JAHH...12..141C. doi:10.3724/SP.J.1440-2807.2009.02.06. S2CID 18990068. PDF +Altschuler, Daniel R.; Salter, Christopher J. (2013). "The Arecibo Observatory: Fifty astronomical years". Physics Today. 66 (11): 43. Bibcode:2013PhT....66k..43A. doi:10.1063/PT.3.2179. + +== External links == + +Official website +Youtube video of collapse 12.56 mins +The wondrous life—and dramatic death—of Puerto Rico's Arecibo Observatory \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_message-0.md b/data/en.wikipedia.org/wiki/Arecibo_message-0.md new file mode 100644 index 000000000..7252e7fc2 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_message-0.md @@ -0,0 +1,56 @@ +--- +title: "Arecibo message" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Arecibo_message" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:36.583072+00:00" +instance: "kb-cron" +--- + +The Arecibo message is an interstellar radio message carrying basic information about humanity and Earth that was sent to the globular cluster Messier 13 (M13) in 1974. It was meant as a demonstration of human technological achievement rather than a real attempt to enter into a conversation with extraterrestrials. +The message was broadcast into space a single time via frequency-modulated radio waves at a ceremony to mark the remodeling of the Arecibo Telescope in Puerto Rico on 16 November 1974. The message was aimed at the current location of M13, about 25,000 light years from Earth, because M13 was a large and relatively close collection of stars that was available in the sky at the time and place of the ceremony. When correctly translated into graphics, characters, and spaces, the 1,679 bits of data contained within the message form the image shown here. + +== Description == +The content of the Arecibo message was designed by a group of Cornell University and Arecibo scientists: Frank Drake, formulator of the Drake equation, James C. G. Walker, Linda M. French, and Richard Isaacman. Carl Sagan and others also contributed. The message was meant more as a demonstration of human technological achievement than a serious attempt to enter into a conversation with possible extraterrestrials. As globular cluster M13, at which the message was aimed, is more than 25,000 light-years from Earth, the message, traveling at the speed of light, will take at least 25,000 years to arrive there. By that time, the core of M13 will no longer be in precisely the same location because of the orbit of the star cluster around the Galactic Center. Even so, the proper motion of M13 is small, so the message will still arrive near the center of the cluster. +The message consists of seven parts that encode the following (from the top down in the image): + +The numbers one to ten (white; left to right) +The atomic numbers of the elements hydrogen, carbon, nitrogen, oxygen, and phosphorus, which make up deoxyribonucleic acid (DNA) (purple) +The formulas for the chemical compounds that make up the nucleotides of DNA (green) +The estimated number of DNA nucleotides in the human genome, and a graphic of the double helix structure of DNA (white and blue, respectively) +The dimension (physical height, 5'9") of an average man (blue/white), a graphic figure of a human being (red), and the human population of Earth which was about 4 billion at the time (white) +A graphic of the Solar System (including Pluto), indicating which of the planets the message is coming from (yellow). The Sun is on the left and the third planet, Earth, raised toward the human figure +A graphic of the Arecibo radio telescope and the dimension (the physical diameter) of the transmitting antenna dish (purple, white, and blue) +The entire message consisted of 1,679 binary digits, approximately 210 bytes, transmitted at a frequency of 2,380 MHz and modulated by shifting the frequency by 10 Hz, with a power of 450 kW. The "ones" and "zeros" were transmitted by frequency shifting at the rate of 10 bits per second. The total broadcast was less than three minutes. +The number 1,679 was chosen because it is a semiprime (the product of two prime numbers), to be arranged rectangularly as 73 rows by 23 columns. The alternative arrangement, 23 rows by 73 columns, produces an unintelligible set of characters. + +=== Message as binary string === +The message as a binary string is included below. Note that the choice of 1 representing higher frequency and 0 representing lower frequency is entirely arbitrary and the line breaks after every 23 bits are only included to allow for some ease in human readability. + +=== Numbers === + +1 2 3 4 5 6 7 8 9 10 +---------------------- +0 0 0 1 1 1 1 00 00 00 +0 1 1 0 0 1 1 00 00 10 +1 0 1 0 1 0 1 01 11 01 +X X X X X X X X X X <-Least-significant-digit marker. + +The numbers from 1 to 10 appear in binary format, to be read from the top down. The bottom row contains markers which indicate the column from which the binary code for each number is intended to begin. +Even assuming that any extraterrestrial recipients would recognize binary, the encoding of the numbers may not be immediately obvious because of the way they have been written. To read the first seven digits, ignore the bottom row, and read them as three binary digits from top to bottom, with the top digit being the most significant. The readings for 8, 9, and 10 are a little different, as their binary code has been distributed across an additional column next to the first (to the right in the image). This is intended to show that numbers too large to fit in a single column can be written in several contiguous ones (a scheme which is used elsewhere in the message). The additional columns are not marked by the least-significant-digit marker. + +=== DNA elements === + +H C N O P +1 6 7 8 15 +---------- +0 0 0 1 1 +0 1 1 0 1 +0 1 1 0 1 +1 0 1 0 1 +X X X X X + +The numbers 1, 6, 7, 8, and 15 appear, denoting the atomic numbers of hydrogen (H), carbon (C), nitrogen (N), oxygen (O), and phosphorus (P), the elements from which DNA is composed. + +=== Nucleotides === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_message-1.md b/data/en.wikipedia.org/wiki/Arecibo_message-1.md new file mode 100644 index 000000000..44fa11d63 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_message-1.md @@ -0,0 +1,74 @@ +--- +title: "Arecibo message" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Arecibo_message" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:36.583072+00:00" +instance: "kb-cron" +--- + +The chemical groups from which the nucleotides of polymeric DNA sequences are built – the sugar deoxyribose, phosphate, and the four canonical nucleobases used in DNA – are then described as sequences of the five elements that appear on the preceding line. Each sequence represents the molecular formula of the chemical as it exists when incorporated into DNA (as opposed to the free form). +For example, the compound in the top left in the image is deoxyribose (C5H7O in DNA, C5H10O4 when free), whose formula is read as: + +11000 +10000 +11010 +XXXXX +----- +75010 + +i.e., 7 atoms of hydrogen, 5 atoms of carbon, 0 atoms of nitrogen, 1 atom of oxygen, and 0 atoms of phosphorus. +It is displayed in this order because the DNA Elements in the previous section (Purple image as reference) describe hydrogen (H), carbon (C), nitrogen (N), oxygen (O), and phosphorus (P) in that order as well. + +=== Double helix === + +11 +11 +11 +11 +11 +01 +11 +11 +01 +11 +01 +11 +10 +11 +11 +01 +X + +11111111 11110111 11111011 01011110 (binary) [Using the double vertical columns above, read from top to bottom starting from the right column first, and then top to bottom from the left column.] += 4,294,441,822 (decimal) + +A graphic of the approximate shape of the double helix in which double-stranded DNA polymers naturally exist; the vertical bar in the middle is a binary representation of the number of nucleotide base pairs in the human genome. The value depicted is around 4.3 billion, which was believed to be the case when the message was transmitted in 1974; it is now known that there are only approximately 3.2 billion base pairs in the human genome. + +=== Humanity === + +The graphic in the center is a simple illustration of a human being. The element on the left (in the image) indicates the average height of an adult male in the US: 1.764 m (5 ft 9.4 in). This value is indicated by a horizontally written binary representation of the number 14, which is intended to be multiplied by the wavelength of the message (126 mm); 14 × 126 = 1,764 millimeters. +The element on the right of the image indicates the size of the global human population in 1974, approximately 4.3 billion (which, coincidentally, is within 0.1% of the number of DNA base pairs suggested for the size of the human genome earlier in the message). In this case, the number is oriented in the data horizontally rather than vertically. The least-significant-digit marker is in the upper left in the image, with bits going to the right and more significant digits below. + +=== Planets === + + Earth +Sun Mercury Venus Mars Jupiter Saturn Uranus Neptune Pluto + +A graphic depicting the Solar System, showing the Sun and nine planets in the order of their distance from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto (Pluto was reclassified in 2006 as a dwarf planet by the International Astronomical Union). Earth is the third planet from the Sun; its graphic is shifted up to identify it as the planet from which the signal was sent. Additionally, the human figure is shown just above the Earth graphic. +In addition to showing position, the graphic provides a general, not-to-scale size reference of each planet and the Sun. + +=== Telescope === + +bottom middle two rows shown in White as reference in the image: + 100101 +<--- 111110X --->100101 111110 (binary) = 2,430 (decimal) + +The last part is a graphic representing the Arecibo radio telescope and indicating its diameter with a binary representation of the number 2,430; multiplying by the wavelength of 126 mm gives 306.18 m (1,004 ft 6 in). In this case, the number is oriented horizontally, with the least-significant-digit marker to the lower right in the image. +The part of the image that resembles a letter "M" is there to demonstrate that the curved line is a concave curved mirror. + +== Arecibo Answer crop circle hoax == + +The "Hampshire pattern" or "Chilbolton Code formation" or "Arecibo answer" was a crop circle that appeared in 2001 near the Chilbolton radio telescope in Hampshire, UK, which echoed the visual representation and most of the information from the original Arecibo message with some significant differences including location/origin, DNA configuration, and appearance. +The SETI Institute Online rebutted the idea that this was a genuine extraterrestrial response, by saying, "This is highly improbable. There is no evidence to suggest an other-than-earthly origin for these graphics." The crop circle is a near replica of the Arecibo message, with the same 23 × 73 grid. Most of the chemical data remains the same, with the exception that in the section detailing important chemical elements, silicon has been added, and the diagram of DNA has been rewritten. At the bottom, the pictogram of a human is replaced with a figure with a large, bulbous head. A solar system with 9 planets is also depicted, with emphasis placed on the 3rd, 4th, and 5th planets of the system. The Arecibo telescope is replaced by a replica of a crop circle that appeared in the same field one year before, and the binary representation of the transmitter's diameter is altered. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arecibo_message-2.md b/data/en.wikipedia.org/wiki/Arecibo_message-2.md new file mode 100644 index 000000000..1fd86c012 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arecibo_message-2.md @@ -0,0 +1,28 @@ +--- +title: "Arecibo message" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Arecibo_message" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:36.583072+00:00" +instance: "kb-cron" +--- + +== Computational analysis == +Some researchers have analysed whether the Arecibo signal could be identified as a carrying message by some information theoretic measure that was agnostic in the sense that it does not know the particular shapes of a human or double-helix etc. Presumably such an agnostic measure would be all that any potential ETI could apply to this signal. It is also a useful testbed for humanity's own ability to detect potential extraterrestrial signals, as we would presumably be similarly agnostic about any shapes particularly special to the broadcasting ETI. +Mahon (2025) described an information theoretic measure of complexity, the LCC score, that gives a high score to human language and meaningful images (such as photographs or drawings), and to the Arecibo message, while also giving a low score to random noise signals and simple repetitive signals. This measure also identified the correct aspect ratio of 73 by 23. Other attempts have been made with varying degrees of success. Zenil et al. (2023) also identified the correct aspect ratio and distinguished it from random noise signals, but not from uniform or repetitive signals. McCowan et al. (1999) described a measure called entropic slope, which could differentiate between random noise or repetitive signals, and meaningful vocalisations by multiple species including humans, but did not detect a message in the Arecibo signal. + +== See also == +Active SETI +Communication with extraterrestrial intelligence (CETI) +Cosmos, a 2019 science fiction film featuring a response to the Arecibo message +List of interstellar radio messages +METI (Messaging Extraterrestrial Intelligence) (organization) +Pioneer plaque +Voyager Golden Record +Wow! signal + +== References == + +== External links == + Media related to Arecibo message at Wikimedia Commons \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-0.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-0.md new file mode 100644 index 000000000..d3a4f5493 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-0.md @@ -0,0 +1,30 @@ +--- +title: "Arthur C. Clarke" +chunk: 1/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +Sir Arthur Charles Clarke (16 December 1917 – 19 March 2008) was an English science fiction writer, science writer, futurist, inventor, undersea explorer, and television series host. +Clarke was a science fiction writer, an avid populariser of space travel, and a futurist of distinguished ability. He wrote many books and many essays for popular magazines. In 1961, he received the Kalinga Prize, a UNESCO award for popularising science. Clarke's science and science fiction writings earned him the moniker "Prophet of the Space Age". His science fiction writings in particular earned him a number of Hugo and Nebula awards, which, along with a large readership, made him one of the towering figures of the genre. For many years, science fiction had a "Big Three", comprising Clarke and American writers Robert Heinlein and Isaac Asimov. Clarke co-wrote the screenplay for the 1968 film 2001: A Space Odyssey, widely regarded as one of the most influential films of all time. +Clarke was a lifelong proponent of space travel. In 1934, while still a teenager, he joined the British Interplanetary Society (BIS). In 1945, he proposed a satellite communication system using geostationary orbits. He was the chairman of the BIS from 1946 to 1947 and again in 1951–1953. +Clarke emigrated to Ceylon (now Sri Lanka) in 1956, to pursue his interest in scuba diving. That year, he discovered the underwater ruins of the ancient original Koneswaram Temple in Trincomalee. Clarke augmented his popularity in the 1980s, as the host of television shows such as Arthur C. Clarke's Mysterious World. He lived in Sri Lanka until his death. +Clarke was appointed Commander of the Order of the British Empire (CBE) in 1989 "for services to British cultural interests in Sri Lanka". He was knighted in 1998 and was awarded Sri Lanka's highest civil honour, Sri Lankabhimanya, in 2005. + +== Biography == + +=== Early years === +Clarke was born in Minehead, Somerset, England, and grew up in nearby Bishops Lydeard. As a boy, he lived on a farm, where he enjoyed stargazing, fossil collecting, and reading American science fiction pulp magazines. He received his secondary education at Huish's Grammar School in Taunton. Some of his early influences included dinosaur cigarette cards, which led to an enthusiasm for fossils starting about 1925. Clarke attributed his interest in science fiction to reading three items: the November 1928 issue of Amazing Stories in 1929; Last and First Men by Olaf Stapledon in 1930; and The Conquest of Space by David Lasser in 1931. +In his teens, he joined the Junior Astronomical Association and contributed to Urania, the society's journal, which was edited in Glasgow by Marion Eadie. At Clarke's request, she added an "Astronautics" section, which featured a series of articles written by him on spacecraft and space travel. Clarke also contributed pieces to the "Debates and Discussions Corner", a counterpoint to a Urania article offering the case against space travel, and also his recollections of the Walt Disney film Fantasia. He moved to London in 1936 and joined the Board of Education as a pensions auditor. He and some fellow science fiction writers shared a flat in Gray's Inn Road, where he got the nickname "Ego" because of his absorption in subjects that interested him, and later named his office filled with memorabilia as his "ego chamber". + +=== World War II === +During the Second World War from 1941 to 1946, he served in the Royal Air Force as a radar specialist and was involved in the early-warning radar defence system, which contributed to the RAF's success during the Battle of Britain. Clarke spent most of his wartime service working on ground-controlled approach (GCA) radar, as documented in the semiautobiographical Glide Path, his only non-science fiction novel. Although GCA did not see much practical use during the war, after several years of development it proved vital to the Berlin Airlift of 1948–1949. Clarke initially served in the ranks and was a corporal instructor on radar at No. 2 Radio School, RAF Yatesbury in Wiltshire. He was commissioned as a pilot officer (technical branch) on 27 May 1943. He was promoted to flying officer on 27 November 1943. He was appointed chief training instructor at RAF Honiley in Warwickshire and was demobilised with the rank of flight lieutenant. + +=== Post-war === +After the war, he attained a first-class degree in mathematics and physics from King's College London. After this, he worked as assistant editor at Physics Abstracts. Clarke served as president of the British Interplanetary Society from 1946 to 1947 and again from 1951 to 1953. +Although he was not the originator of the concept of geostationary satellites, one of his most important contributions in this field was his idea that they would be ideal telecommunications relays. He advanced this idea in a paper privately circulated among the core technical members of the British Interplanetary Society in 1945. The concept was published in Wireless World in October of that year. Clarke also wrote a number of nonfiction books describing the technical details and societal implications of rocketry and space flight. The most notable of these may be Interplanetary Flight: An Introduction to Astronautics (1950), The Exploration of Space (1951), and The Promise of Space (1968). In recognition of these contributions, the geostationary orbit 36,000 kilometres (22,000 mi) above the equator is officially recognised by the International Astronomical Union as the Clarke Orbit. +His 1951 book, The Exploration of Space, was used by the rocket pioneer Wernher von Braun to convince President John F. Kennedy that it was possible to go to the Moon. +Following the 1968 release of 2001, Clarke became much in demand as a commentator on science and technology, especially at the time of the Apollo space program. On 20 July 1969, Clarke appeared as a commentator for the CBS News broadcast of the Apollo 11 Moon landing. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-1.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-1.md new file mode 100644 index 000000000..295b6cadd --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-1.md @@ -0,0 +1,36 @@ +--- +title: "Arthur C. Clarke" +chunk: 2/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +=== Sri Lanka and diving === +Clarke lived in Sri Lanka from 1956 until his death in 2008, first in Unawatuna on the south coast, and then in Colombo. Initially, he and his friend Mike Wilson travelled around Sri Lanka, diving in the coral waters around the coast with the Beachcombers Club. In 1957, during a dive trip off Trincomalee, Clarke discovered the underwater ruins of a temple, which subsequently made the region popular with divers. He described it in his 1957 book The Reefs of Taprobane. This was his second diving book after the 1956 The Coast of Coral. Though Clarke lived mostly in Colombo, he set up a small dive school and a simple dive shop near Trincomalee. He dived often at Hikkaduwa, Trincomalee, and Nilaveli. +The Sri Lankan government offered Clarke resident guest status in 1975. He was held in such high esteem that when fellow science fiction writer Robert A. Heinlein came to visit, the Sri Lanka Air Force provided a helicopter to take them around the country. +In the early 1970s, Clarke signed a three-book publishing deal, a record for a science fiction writer at the time. The first of the three was Rendezvous with Rama in 1973, which won all the main genre awards and spawned sequels that along with the 2001 series formed the backbone of his later career. + +In 1986, Clarke was named a Grand Master by the Science Fiction Writers of America. +In 1988, he was diagnosed with post-polio syndrome, having originally contracted polio in 1962, and needed to use a wheelchair most of the time thereafter. Clarke was for many years a vice-patron of the British Polio Fellowship. +In the 1989 Queen's Birthday Honours, Clarke was appointed Commander of the Order of the British Empire (CBE) "for services to British cultural interests in Sri Lanka". The same year, he became the first chancellor of the International Space University, serving from 1989 to 2004. He also served as chancellor of Moratuwa University in Sri Lanka from 1979 to 2002. +In 1994, Clarke appeared in a science fiction film; he portrayed himself in the film Without Warning, an American production about an apocalyptic alien first-contact scenario presented in the form of a faux newscast. +Clarke also became active in promoting the protection of gorillas and became a patron of the Gorilla Organization, which fights for the preservation of gorillas. When tantalum mining for mobile phone manufacture threatened the gorillas in 2001, he lent his voice to their cause. The dive shop that he set up continues to operate from Trincomalee through the Arthur C Clarke Foundation. + +=== Television series host === +In the 1980s and early 1990s, Clarke presented his television programmes Arthur C. Clarke's Mysterious World, Arthur C. Clarke's World of Strange Powers, and Arthur C. Clarke's Mysterious Universe. + +=== Personal life === +On a trip to Florida in 1953, Clarke met and quickly married Marilyn Mayfield, a 22-year-old American divorcee with a young son. They separated permanently after six months, although the divorce was not finalised until 1964. "The marriage was incompatible from the beginning", said Clarke. Marilyn never remarried and died in 1991. +Clarke also never remarried, but was close to a Sri Lankan man, Leslie Ekanayake (13 July 1947 – 4 July 1977), whom Clarke called his "only perfect friend of a lifetime" in the dedication to his novel The Fountains of Paradise. Clarke is buried with Ekanayake, who predeceased him by three decades, in Kanatte Cemetery, Colombo's main burial ground and crematorium. In his biography of Stanley Kubrick, John Baxter cites Clarke's homosexuality as a reason why he relocated, due to more tolerant laws with regard to homosexuality in Sri Lanka. Journalists who enquired of Clarke whether he was gay were told, "No, merely mildly cheerful." However, Michael Moorcock wrote: + +Everyone knew he was gay. In the 1950s, I'd go out drinking with his boyfriend. We met his protégés, western and eastern, and their families, people who had only the most generous praise for his kindness. Self-absorbed he might be and a teetotaller, but an impeccable gent through and through. +In an interview in the July 1986 issue of Playboy magazine, when asked if he had had a bisexual experience, Clarke stated, "Of course. Who hasn't?". In his obituary, Clarke's friend Kerry O'Quinn wrote: "Yes, Arthur was gay ... As Isaac Asimov once told me, 'I think he simply found he preferred men.' Arthur didn't publicise his sexuality – that wasn't the focus of his life – but if asked, he was open and honest." +Clarke accumulated a vast collection of manuscripts and personal memoirs, maintained by his brother Fred Clarke in Taunton, Somerset, England, and referred to as the "Clarkives". Clarke said some of his private diaries will not be published until 30 years after his death. When asked why they were sealed, he answered, "Well, there might be all sorts of embarrassing things in them." + +=== Knighthood === +On 26 May 2000, he was made a Knight Bachelor "for services to literature" at a ceremony in Colombo. The knighthood had been awarded in the 1998 New Year Honours list, but investiture with the award had been delayed, at Clarke's request, because of an accusation by the tabloid the Sunday Mirror of paying boys for sex. The charge was subsequently found to be baseless by the Sri Lankan police. According to The Daily Telegraph, the Sunday Mirror subsequently published an apology, and Clarke chose not to sue for defamation. The Independent alleged that a similar story was not published because Clarke was a friend of newspaper tycoon Rupert Murdoch. Clarke himself said, "I take an extremely dim view of people mucking about with boys", and Rupert Murdoch allegedly promised him the reporters responsible would never work in Fleet Street again. + +=== Later years === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-2.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-2.md new file mode 100644 index 000000000..b2f9b4924 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-2.md @@ -0,0 +1,32 @@ +--- +title: "Arthur C. Clarke" +chunk: 3/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +Although he and his home were unharmed by the 2004 Indian Ocean earthquake tsunami, his "Arthur C. Clarke Diving School" (now called "Underwater Safaris") at Hikkaduwa near Galle was destroyed. He made humanitarian appeals, and the Arthur C. Clarke Foundation worked towards better disaster notification systems. +Because of his post-polio deficits, which limited his ability to travel and gave him halting speech, most of Clarke's communications in his last years were in the form of recorded addresses. In July 2007, he provided a video address for the Robert A. Heinlein Centennial in which he closed his comments with a goodbye to his fans. In September 2007, he provided a video greeting for NASA's Cassini probe's flyby of Iapetus (which plays an important role in the book of 2001: A Space Odyssey). In December 2007 on his 90th birthday, Clarke recorded a video message to his friends and fans bidding them good-bye. +Clarke died in Colombo on 19 March 2008, at the age of 90. His aide described the cause as respiratory complications and heart failure stemming from post-polio syndrome. +Just hours before Clarke's death, a major gamma-ray burst (GRB) reached Earth. Known as GRB 080319B, the burst set a new record as the farthest object that can be seen from Earth with the naked eye. It occurred about 7.5 billion years ago, the light taking that long to reach Earth. Larry Sessions, a science writer for Sky and Telescope magazine blogging on earthsky.org, suggested that the burst be named the "Clarke Event". American Atheist Magazine wrote of the idea: "It would be a fitting tribute to a man who contributed so much, and helped lift our eyes and our minds to a cosmos once thought to be province only of gods." +A few days before he died, he had reviewed the manuscript of his final work, The Last Theorem, on which he had collaborated by e-mail with contemporary Frederik Pohl. The book was published after Clarke's death. Clarke was buried in Colombo in traditional Sri Lankan fashion on 22 March. His younger brother, Fred Clarke, and his Sri Lankan adoptive family were among the thousands in attendance. +Clarke's papers were donated to the American National Air and Space Museum in 2014. +On 8 January 2024, a sample of Clarke's DNA was launched on the Peregrine Mission One to the Moon. The Peregrine spacecraft failed to land on the Moon, and the spacecraft disintegrated in the Earth's atmosphere on 19 January 2024. + +== Science fiction writer == + +=== Beginnings === +While Clarke had a few stories published in fanzines, between 1937 and 1945, his first professional sale appeared in Astounding Science Fiction in 1946: "Loophole" was published in April, while "Rescue Party", his first sale, was published in May. Along with his writing, Clarke briefly worked as assistant editor of Science Abstracts (1949) before devoting himself in 1951 to full-time writing. +Clarke began carving out his reputation as a "scientific" science fiction writer with his first science fiction novel, Against the Fall of Night, published as a novella in 1948. It was very popular and considered ground-breaking work for some of the concepts it contained. Clarke revised and expanded the novella into a full novel, which was published in 1953. Clarke later rewrote and expanded this work a third time to become The City and the Stars in 1956, which rapidly became a definitive must-read in the field. His third science fiction novel, Childhood's End, was also published in 1953, cementing his popularity. Clarke capped the first phase of his writing career with his sixth novel, A Fall of Moondust, in 1961, which is also an acknowledged classic of the period. +During this time, Clarke corresponded with C. S. Lewis in the 1940s and 1950s and they once met in an Oxford pub, the Eastgate, to discuss science fiction and space travel. Clarke voiced great praise for Lewis upon his death, saying The Ransom Trilogy was one of the few works of science fiction that should be considered literature. + +=== "The Sentinel" === + +In 1948, he wrote "The Sentinel" for a BBC competition. Though the story was rejected, it changed the course of Clarke's career. Not only was it the basis for 2001: A Space Odyssey, but "The Sentinel" also introduced a more cosmic element to Clarke's work. Many of Clarke's later works feature a technologically advanced but still-prejudiced mankind being confronted by a superior alien intelligence. In the cases of Childhood's End, and the 2001 series, this encounter produces a conceptual breakthrough that accelerates humanity into the next stage of its evolution. This also applies in the far-distant past (but our future) in The City and the Stars (and its original version, Against the Fall of Night). +In Clarke's authorised biography, Neil McAleer writes: "many readers and critics still consider Childhood's End Arthur C. Clarke's best novel." But Clarke did not use ESP in any of his later stories, saying, "I've always been interested in ESP, and of course, Childhood's End was about that. But I've grown disillusioned, partly because after all this time, they're still arguing about whether these things happen. I suspect that telepathy does happen." +A collection of early essays was published in The View from Serendip (1977), which also included one short piece of fiction, "When the Twerms Came". Clarke also wrote short stories under the pseudonyms of E. G. O'Brien and Charles Willis. Almost all of his short stories can be found in the book The Collected Stories of Arthur C. Clarke (2001). + +=== "Big Three" === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-3.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-3.md new file mode 100644 index 000000000..d904ca321 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-3.md @@ -0,0 +1,24 @@ +--- +title: "Arthur C. Clarke" +chunk: 4/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +For much of the later 20th century, Clarke, Isaac Asimov, and Robert A. Heinlein were informally known as the "Big Three" of science fiction writers. Clarke and Heinlein began writing to each other after The Exploration of Space was published in 1951, and first met in person the following year. They remained on cordial terms for many years, including during visits to the United States and Sri Lanka. +Clarke and Asimov first met in New York City in 1953, and they traded friendly insults and gibes for decades. They established an oral agreement, the "Clarke–Asimov Treaty", that when asked who was better, the two would say Clarke was the better science fiction writer and Asimov was the better science writer. In 1972, Clarke put the "treaty" on paper in his dedication to Report on Planet Three and Other Speculations. +In 1984, Clarke testified before Congress against the Strategic Defense Initiative (SDI). Later, at the home of Larry Niven in California, a concerned Heinlein attacked Clarke's views on United States foreign and space policy (especially the SDI), vigorously advocating a strong defence posture. Although the two later reconciled formally, they remained distant until Heinlein's death in 1988. + +=== Space Odyssey series === +2001: A Space Odyssey, Clarke's most famous work, was extended well beyond the original 1968 film as the Space Odyssey series. In 1982, Clarke wrote a sequel to 2001 titled 2010: Odyssey Two, which was made into a film in 1984. Clarke wrote two further sequels which have not been adapted into motion pictures: 2061: Odyssey Three (published in 1987) and 3001: The Final Odyssey (published in 1997). +2061: Odyssey Three involves a visit to Halley's Comet on its next plunge through the Inner Solar System and a spaceship crash on the Jovian moon Europa. The whereabouts of astronaut Dave Bowman (the "Star Child"), the artificial intelligence HAL 9000, and the development of native life on Europa, protected by the alien Monolith, are revealed. +Finally, in 3001: The Final Odyssey, astronaut Frank Poole's freeze-dried body, found by a spaceship beyond the orbit of Neptune, is revived by advanced medical science. The novel details the threat posed to humanity by the alien monoliths, whose actions are not always as their builders had intended. + +==== 2001: A Space Odyssey ==== +Clarke's first venture into film was 2001: A Space Odyssey, directed by Stanley Kubrick. Kubrick and Clarke had met in New York City in 1964 to discuss the possibility of a collaborative film project. As the idea developed, they decided to loosely base the story on Clarke's short story, "The Sentinel", written in 1948 as an entry in a BBC short-story competition. Originally, Clarke was going to write the screenplay for the film, but Kubrick suggested during one of their brainstorming meetings that before beginning on the actual script, they should let their imaginations soar free by writing a novel first, on which they would base the film. "This is more or less the way it worked out, though toward the end, novel and screenplay were being written simultaneously, with feedback in both directions. Thus, I rewrote some sections after seeing the movie rushes – a rather expensive method of literary creation, which few other authors can have enjoyed." The novel ended up being published a few months after the release of the movie. + +Due to the hectic schedule of the film's production, Kubrick and Clarke had difficulty collaborating on the book. Clarke completed a draft of the novel at the end of 1964 with the plan to publish in 1965 in advance of the film's release in 1966. After many delays, the film was released in the spring of 1968, before the book was completed. The book was credited to Clarke alone. Clarke later complained that this had the effect of making the book into a novelisation, and that Kubrick had manipulated circumstances to play down Clarke's authorship. For these and other reasons, the details of the story differ slightly from the book to the movie. The film contains little explanation for the events taking place. Clarke, though, wrote thorough explanations of "cause and effect" for the events in the novel. James Randi later recounted that upon seeing the premiere of 2001, Clarke left the theatre at the intermission in tears, after having watched an eleven-minute scene (which did not make it into general release) where an astronaut is doing nothing more than jogging inside the spaceship, which was Kubrick's idea of showing the audience how boring space travels could be. +In 1972, Clarke published The Lost Worlds of 2001, which included his accounts of the production, and alternative versions of key scenes. The "special edition" of the novel A Space Odyssey (released in 1999) contains an introduction by Clarke in which he documents the events leading to the release of the novel and film. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-4.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-4.md new file mode 100644 index 000000000..01ba31991 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-4.md @@ -0,0 +1,28 @@ +--- +title: "Arthur C. Clarke" +chunk: 5/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +==== 2010: Odyssey Two ==== +In 1982, Clarke continued the 2001 epic with a sequel, 2010: Odyssey Two. This novel was also made into a film, 2010, directed by Peter Hyams for release in 1984. Because of the political environment in America in the 1980s, the film presents a Cold War theme, with the looming tensions of nuclear warfare not featured in the novel. The film was not considered to be as revolutionary or artistic as 2001, but the reviews were still positive. +Clarke's email correspondence with Hyams was published in 1984. Titled The Odyssey File: The Making of 2010, and co-authored with Hyams, it illustrates his fascination with the then-pioneering medium of email and its use for them to communicate on an almost daily basis at the time of planning and production of the film while living on opposite sides of the world. The book also included Clarke's personal list of the best science fiction films ever made. +Clarke appeared in the film, first as the man feeding the pigeons while Dr. Heywood Floyd is engaged in a conversation in front of the White House. Later, in the hospital scene with David Bowman's mother, an image of the cover of Time portrays Clarke as the American President and Kubrick as the Soviet Premier. + +=== Rendezvous with Rama === +In 1996, Sierra Entertainment created Rama as a point and click adventure game in the style of Myst. Along with highly detailed graphics, Arthur C. Clarke also appeared in the game as the guide for the player. This game featured details from Rendezvous with Rama and characters from the Rama II novel. +Rendezvous with Rama was optioned for filmmaking in the early 21st century but this motion picture has remained in "development hell". After a drawn-out development process, which actor Morgan Freeman attributed to difficulties in getting financing, it appeared in 2003 that this project might be proceeding. The film was to be produced by Freeman's production company, Revelations Entertainment, with David Fincher being touted as the film's director. After years of no progress, in late 2008, Fincher stated the movie is unlikely to be made, given Morgan Freeman's health. In 2010, though, the film was still planned for future production and both Freeman and Fincher mentioned it as still needing a worthy script. In late 2021, Denis Villeneuve was introduced as director. + +== Science writer == +Clarke published a number of nonfiction books with essays, speeches, addresses, etc. Several of his nonfiction books are composed of chapters that can stand on their own as separate essays. + +=== Space travel === +In particular, Clarke was a populariser of the concept of space travel. In 1950, he wrote Interplanetary Flight, a book outlining the basics of space flight for laymen. Later books about space travel included The Exploration of Space (1951), The Challenge of the Spaceship (1959), Voices from the Sky (1965), The Promise of Space (1968, rev. ed. 1970), and Report on Planet Three (1972) along with many others. + +=== Futurism === +His books on space travel usually included chapters about other aspects of science and technology, such as computers and bioengineering. He predicted telecommunication satellites (albeit serviced by astronauts in space suits, who would replace the satellite's vacuum tubes as they burned out). +His many predictions culminated in 1958 when he began a series of magazine essays which eventually became Profiles of the Future, published in book form in 1962. A timetable up to the year 2100 describes inventions and ideas including such things as a "global library" for 2005. The same work also contained "Clarke's First Law" and text that became Clarke's three laws in later editions. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-5.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-5.md new file mode 100644 index 000000000..214824dd0 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-5.md @@ -0,0 +1,25 @@ +--- +title: "Arthur C. Clarke" +chunk: 6/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +In a 1959 essay, Clarke predicted global satellite TV broadcasts that would cross national boundaries indiscriminately and would bring hundreds of channels available anywhere in the world. He also envisioned a "personal transceiver, so small and compact that every man carries one". He wrote: "the time will come when we will be able to call a person anywhere on Earth merely by dialing a number." Such a device would also, in Clarke's vision, include means for global positioning so "no one need ever again be lost". Later, in Profiles of the Future, he predicted the advent of such a device taking place in the mid-1980s. Clarke described a global computer network similar to the modern World Wide Web in a 1964 presentation for the BBC's Horizon programme, predicting that, by the 21st century, access to information and even physical tasks such as surgery could be accomplished remotely and instantaneously from anywhere in the world using internet and satellite communication. +In a 1974 interview with the Australian Broadcasting Corporation, the interviewer asked Clarke how he believed the computer would change the future for the everyday person, and what life would be like in the year 2001. Clarke accurately predicted many things that became reality, including online banking, online shopping, and other now commonplace things. Responding to a question about how the interviewer's son's life would be different, Clarke responded: "He will have, in his own house, not a computer as big as this, [points to nearby computer], but at least, a console through which he can talk, through his friendly local computer and get all the information he needs, for his everyday life, like his bank statements, his theatre reservations, all the information you need in the course of living in our complex modern society, this will be in a compact form in his own house ... and he will take it as much for granted as we take the telephone." +An extensive selection of Clarke's essays and book chapters (from 1934 to 1998; 110 pieces, 63 of them previously uncollected in his books) can be found in the book Greetings, Carbon-Based Bipeds! (2000), together with a new introduction and many prefatory notes. Another collection of essays, all previously collected, is By Space Possessed (1993). Clarke's technical papers, together with several essays and extensive autobiographical material, are collected in Ascent to Orbit: A Scientific Autobiography (1984). + +== Geostationary communications satellite == + +Clarke contributed to the popularity of the idea that geostationary satellites would be ideal telecommunications relays. He first described this in a letter to the editor of Wireless World in February 1945 and elaborated on the concept in a paper titled Extra-Terrestrial Relays – Can Rocket Stations Give Worldwide Radio Coverage?, published in Wireless World in October 1945. The geostationary orbit is sometimes known as the Clarke orbit or the Clarke belt in his honour. +It is not clear that this article was actually the inspiration for the modern telecommunications satellite. According to John R. Pierce, of Bell Labs, who was involved in the Echo satellite and Telstar projects, he gave a talk upon the subject in 1954 (published in 1955), using ideas that were "in the air", but was not aware of Clarke's article at the time. In an interview given shortly before his death, Clarke was asked whether he had ever suspected that one day communications satellites would become so important; he replied: "I'm often asked why I didn't try to patent the idea of a communications satellite. My answer is always, 'A patent is really a licence to be sued.'" +Though different from Clarke's idea of telecom relay, the idea of communicating via satellites in geostationary orbit itself had been described earlier. For example, the concept of geostationary satellites was described in Hermann Oberth's 1923 book Die Rakete zu den Planetenräumen (The Rocket into Interplanetary Space), and then the idea of radio communication by means of those satellites in Herman Potočnik's (written under the pseudonym Hermann Noordung) 1928 book Das Problem der Befahrung des Weltraums), sections: Providing for Long Distance Communications and Safety, and (possibly referring to the idea of relaying messages via satellite, but not that three would be optimal) Observing and Researching the Earth's Surface, published in Berlin. Clarke acknowledged the earlier concept in his book Profiles of the Future. + +== Undersea explorer == +Clarke was an avid scuba diver and a member of the Underwater Explorers Club. In addition to writing, Clarke set up several diving-related ventures with his business partner Mike Wilson. In 1956, while scuba diving, Wilson and Clarke uncovered ruined masonry, architecture, and idol images of the sunken original Koneswaram temple – including carved columns with flower insignia, and stones in the form of elephant heads – spread on the shallow surrounding seabed. Other discoveries included Chola bronzes from the original shrine, and these discoveries were described in Clarke's 1957 book The Reefs of Taprobane. +In 1961, while filming off Great Basses Reef, Wilson found a wreck and retrieved silver coins. Plans to dive on the wreck the following year were stopped when Clarke developed paralysis, ultimately diagnosed as polio. A year later, Clarke observed the salvage from the shore and the surface. The ship, ultimately identified as belonging to the Mughal Emperor, Aurangzeb, yielded fused bags of silver rupees, cannon, and other artefacts, carefully documented, became the basis for The Treasure of the Great Reef. Living in Sri Lanka and learning its history also inspired the backdrop for his novel The Fountains of Paradise in which he described a space elevator. This, he believed, would make rocket-based access to space obsolete, and more than geostationary satellites, would ultimately be his scientific legacy. In 2008, he said in an interview with IEEE Spectrum, "maybe in a generation or so the space elevator will be considered equally important" as the geostationary satellite, which was his most important technological contribution. + +== Views == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-6.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-6.md new file mode 100644 index 000000000..f703eb370 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-6.md @@ -0,0 +1,25 @@ +--- +title: "Arthur C. Clarke" +chunk: 7/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +=== Religion === +Themes of religion and spirituality appear in much of Clarke's writing. He said: "Any path to knowledge is a path to God – or Reality, whichever word one prefers to use." He described himself as "fascinated by the concept of God". J. B. S. Haldane, near the end of his life, suggested in a personal letter to Clarke that Clarke should receive a prize in theology for being one of the few people to write anything new on the subject, and went on to say that if Clarke's writings had not contained multiple contradictory theological views, he might have been a menace. When he entered the Royal Air Force, Clarke insisted that his dog tags be marked "pantheist" rather than the default, Church of England, and in a 1991 essay entitled "Credo", described himself as a logical positivist from the age of 10. In 2000, Clarke told the Sri Lankan newspaper, The Island, "I don't believe in God or an afterlife", and he identified himself as an atheist. He was honoured as a Humanist Laureate in the International Academy of Humanism. He has also described himself as a "crypto-Buddhist", insisting Buddhism is not a religion. He displayed little interest about religion early in his life, for example, only discovering a few months after marrying that his wife had strong Presbyterian beliefs. +Later in his life, Clarke began to hold a more hostile view of religion. A famous quotation of Clarke's is often cited: "One of the great tragedies of mankind is that morality has been hijacked by religion." He was quoted in Popular Science in 2004 as saying of religion: "Most malevolent and persistent of all mind viruses. We should get rid of it as quick as we can." In a three-day "dialogue on man and his world" with Alan Watts, Clarke said he was biased against religion and could not forgive religions for what he perceived as their inability to prevent atrocities and wars over time. In his introduction to the penultimate episode of Mysterious World, entitled "Strange Skies", Clarke said, "I sometimes think that the universe is a machine designed for the perpetual astonishment of astronomers", reflecting the dialogue of the episode, in which he stated this concept more broadly, referring to "mankind". Near the very end of that same episode, the last segment of which covered the Star of Bethlehem, he said his favourite theory was that it might be a pulsar. Given that pulsars were discovered in the interval between his writing the short story, "The Star" (1955), and making Mysterious World (1980), and given the more recent discovery of pulsar PSR B1913+16, he said: "How romantic, if even now, we can hear the dying voice of a star, which heralded the Christian era." +Despite his atheism, themes of deism are a common feature within Clarke's work. Clarke left written instructions for a funeral: "Absolutely no religious rites of any kind, relating to any religious faith, should be associated with my funeral." + +=== Politics === +Regarding freedom of information Clarke believed, "In the struggle for freedom of information, technology, not politics, will be the ultimate decider." Clarke also wrote, "It is not easy to see how the more extreme forms of nationalism can +long survive when men have seen the Earth in its true perspective as a single small +globe against the stars." Clarke opposed claims of sovereignty over space stating "There is hopeful symbolism in the fact that flags do not wave in a vacuum." Clarke was an anti-capitalist, stating that he did not fear automation because, "the goal of the future is full unemployment, so we can play. That's why we have to destroy the present politico-economic system." + +=== Technology === +Regarding human jobs being replaced by robots, Clarke said: "Any teacher that can be replaced by a machine should be!" Clarke supported the use of renewable energy, saying: "I would like to see us kick our current addiction to oil, and adopt clean energy sources ... Climate change has now added a new sense of urgency. Our civilisation depends on energy, but we can't allow oil and coal to slowly bake our planet." + +=== Intelligent life === +About intelligent life and the Fermi paradox, Clarke stated: The best proof that there's intelligent life in outer space is the fact that it hasn't come here ... the fact that we have not yet found the slightest evidence for life—much less intelligence—beyond this Earth does not surprise or disappoint me in the least. Our technology must still be laughably primitive; we may well be like jungle savages listening for the throbbing of tom-toms, while the ether around them carries more words per second than they could utter in a lifetime. Two possibilities exist: either we are alone in the Universe or we are not... Both are equally terrifying. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-7.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-7.md new file mode 100644 index 000000000..7dbe2430d --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-7.md @@ -0,0 +1,27 @@ +--- +title: "Arthur C. Clarke" +chunk: 8/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +=== Paranormal phenomena === +Early in his career, Clarke had a fascination with the paranormal and said it was part of the inspiration for his novel Childhood's End. Citing the numerous promising paranormal claims that were later shown to be fraudulent, Clarke described his earlier openness to the paranormal having turned to being "an almost total sceptic" by the time of his 1992 biography. Similarly, in the prologue to the 1990 Del Rey edition of Childhood's End, he writes: "after ... researching my Mysterious World and Strange Powers programmes, I am an almost total skeptic. I have seen far too many claims dissolve into thin air, far too many demonstrations exposed as fakes. It has been a long, and sometimes embarrassing, learning process." During interviews, both in 1993 and 2004–2005, he stated that he did not believe in reincarnation, saying there was no mechanism to make it possible, though "I'm always paraphrasing J. B. S. Haldane: 'The universe is not only stranger than we imagine, it's stranger than we can imagine.'" He described the idea of reincarnation as fascinating, but favoured a finite existence. +Clarke was known for hosting several television series investigating the unusual: Arthur C. Clarke's Mysterious World (1980), Arthur C. Clarke's World of Strange Power (1985), and Arthur C. Clarke's Mysterious Universe (1994). Topics examined ranged from ancient, man-made artefacts with obscure origins (e.g., the Nazca lines or Stonehenge), to cryptids (purported animals unknown to science), or obsolete scientific theories that came to have alternate explanations (e.g., Martian canals). +In Arthur C. Clarke's Mysterious World, he describes three kinds of "mysteries": + +Mysteries of the First Kind: Something that was once utterly baffling but is now completely understood, e.g. a rainbow. +Mysteries of the Second Kind: Something that is currently not fully understood and can be in the future. +Mysteries of the Third Kind: Something of which we have no understanding. +Clarke's programmes on unusual phenomena were parodied in a 1982 episode of the comedy series The Goodies, in which his show is cancelled after it is claimed that he does not exist. + +== Themes, style, and influences == +Clarke's work is marked by an optimistic view of science empowering mankind's exploration of the Solar System and the world's oceans. His images of the future often feature a Utopian setting with highly developed technology, ecology, and society, based on the author's ideals. His early published stories usually featured the extrapolation of a technological innovation or scientific breakthrough into the underlying decadence of his own society. +A recurring theme in Clarke's works is the notion that the evolution of an intelligent species would eventually make them something close to gods. This was explored in his 1953 novel Childhood's End and briefly touched upon in his novel Imperial Earth. This idea of transcendence through evolution seems to have been influenced by Olaf Stapledon, who wrote a number of books dealing with this theme. Clarke has said of Stapledon's 1930 book Last and First Men that "No other book had a greater influence on my life ... [It] and its successor Star Maker (1937) are the twin summits of [Stapledon's] literary career." +Clarke was well known as an admirer of Irish fantasy writer Lord Dunsany, also having corresponded with him until Dunsany's death in 1957. He described Dunsany as "one of the greatest writers of the century". He also listed H. G. Wells, Jules Verne, and Edgar Rice Burroughs as influences. + +== Awards, honours, and other recognition == +Clarke won the 1963 Stuart Ballantine Medal from the Franklin Institute for the concept of satellite communications, and other honours. He won more than a dozen annual literary awards for particular works of science fiction. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-8.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-8.md new file mode 100644 index 000000000..35a35901e --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-8.md @@ -0,0 +1,57 @@ +--- +title: "Arthur C. Clarke" +chunk: 9/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +In 1952, Clarke won the International Fantasy Award's Non-Fiction category for The Exploration of Space. +In 1956, Clarke won a Hugo Award for his short story, "The Star". +Clarke won the UNESCO–Kalinga Prize for the Popularization of Science in 1961. +He won the Stuart Ballantine Medal in 1963. +He shared a 1969 Academy Award nomination with Stanley Kubrick in the category Best Writing, Story and Screenplay – Written Directly for the Screen for 2001: A Space Odyssey. +The fame of 2001 was enough for the Command Module of the Apollo 13 spacecraft to be named "Odyssey". +Clarke won the Nebula (1973) for his novella, A Meeting with Medusa. +Clarke won both the Nebula (1973) and Hugo (1974) awards and the 1974 Jupiter Award for his novel, Rendezvous with Rama. +Clarke won both the Nebula (1979) and Hugo (1980) awards for his novel, The Fountains of Paradise. +In 1982, he won the Marconi Prize for innovation in communications and remote sensing in space. +In 1985 the Science Fiction Writers of America named him its 7th SFWA Grand Master. +In 1986, he was elected to the American National Academy of Engineering "For conception of geosynchronous communications satellites, and for other contributions to the use and understanding of space". +In 1988, he was awarded an honorary degree (Doctor of Letters) by the University of Bath. +Readers of the British monthly Interzone voted him the all-time second best science fiction author in 1988–1989. +He received a CBE in 1989, and was knighted in 2000. Clarke's health did not allow him to travel to London to receive the latter honour personally from the Queen, so the United Kingdom's High Commissioner to Sri Lanka invested him as a Knight Bachelor at a ceremony in Colombo. +In 1994, Clarke was nominated for a Nobel Peace Prize by law professor Glenn Reynolds. +The Science Fiction and Fantasy Hall of Fame inducted Clarke in 1997, its second class of two deceased and two living persons. Among the living, Clarke and Andre Norton followed A. E. van Vogt and Jack Williamson. +In 2000, he was named a Distinguished Supporter of the British Humanist Association. +The 2001 Mars Odyssey orbiter is named in honour of Clarke's works. +In 2003, Clarke was awarded the Telluride Tech Festival Award of Technology, where he appeared on stage via a 3-D hologram with a group of old friends including Jill Tarter, Neil Armstrong, Lewis Branscomb, Charles Townes, Freeman Dyson, Bruce Murray, and Scott Brown. +In 2004, Clarke won the Heinlein Award for outstanding achievement in hard or science-oriented science fiction. +On 14 November 2005 Sri Lanka awarded Clarke its highest civilian award, the Sri Lankabhimanya (The Pride of Sri Lanka), for his contributions to science and technology and his commitment to his adopted country. +Clarke was the Honorary Board Chair of the Institute for Cooperation in Space, founded by Carol Rosin, and served on the Board of Governors of the American National Space Society, a space advocacy organisation founded by Wernher von Braun. + +=== Named after Clarke === + +==== Awards ==== +Arthur C. Clarke Award for science fiction writing, awarded annually in the United Kingdom. +In 1986, Clarke provided a grant to fund the prize money (initially £1,000) for the Arthur C. Clarke Award for the best science fiction novel published in the United Kingdom in the previous year. In 2001 the prize was increased to £2001, and its value now matches the year (e.g., £2005 in 2005). + +In 2005 he lent his name to the inaugural Sir Arthur Clarke Award, for achievements in space, dubbed the "Space Oscars", awarded annually in the United Kingdom. His brother attended the awards ceremony, and presented an award specially chosen by Arthur (and not by the panel of judges who chose the other awards) to the British Interplanetary Society. +Arthur C. Clarke Foundation awards: "Arthur C. Clarke Innovator's Award" and "Arthur C. Clarke Lifetime Achievement Award" +The Sir Arthur C. Clarke Memorial Trophy Inter School Astronomy Quiz Competition, held in Sri Lanka every year and organised by the Astronomical Association of Ananda College, Colombo. The competition started in 2001 as "The Sir Arthur C. Clarke Trophy Inter School Astronomy Quiz Competition" and was renamed after his death. +Arthur C. Clarke Award for Imagination in Service to Society + +==== Other ==== +An asteroid was named in Clarke's honour, 4923 Clarke (the number was assigned prior to, and independently of, the name – 2001, however appropriate, was unavailable, having previously been assigned to Albert Einstein). +A species of ceratopsian dinosaur, discovered in Inverloch in Australia, was named after Clarke, Serendipaceratops arthurcclarkei. The genus name may also be an allusion to his adopted country, Sri Lanka, one of whose former names is Serendib. +The Learning Resource Centre at Richard Huish College, Taunton, which Clarke attended when it was Huish Grammar School, is named after him. +Clarke was a distinguished vice-president of the H. G. Wells Society, being strongly influenced by Wells as a science fiction writer. +Arthur C. Clarke Institute for Modern Technologies, one of the major research institutes in Sri Lanka, is named after him. +The main protagonist of the Dead Space series of video games, Isaac Clarke, takes his surname from Arthur C. Clarke, and his given name from Clarke's friendly rival and associate Isaac Asimov. +An outer-circular orbital beltway in Colombo, Sri Lanka, was named Arthur C. Clarke Expressway in honour of Clarke. +'The Clarke Event' is a proposed name for GRB 080319B, a gamma-ray burst detected just hours before Clarke's death which set a new record for the most intrinsically bright object ever observed by humans in the universe. +Clarke Montes, a mountain on Pluto's moon Charon, is named after Clarke. + +== Selected works == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Arthur_C._Clarke-9.md b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-9.md new file mode 100644 index 000000000..d67200be4 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Arthur_C._Clarke-9.md @@ -0,0 +1,114 @@ +--- +title: "Arthur C. Clarke" +chunk: 10/10 +source: "https://en.wikipedia.org/wiki/Arthur_C._Clarke" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:52.468453+00:00" +instance: "kb-cron" +--- + +=== Novels === +Against the Fall of Night (1948, 1953), original version of The City and the Stars +Prelude to Space (1951) +The Sands of Mars (1951) +Islands in the Sky (1952) +Childhood's End (1953) +Earthlight (1955) +The City and the Stars (1956) +The Deep Range (1957) +A Fall of Moondust (1961) +Dolphin Island: A Story of the People of the Sea (1963) +Glide Path (1963) +2001: A Space Odyssey (1968), produced alongside the film version with Stanley Kubrick +Rendezvous with Rama (1973) +Imperial Earth (1975) +The Fountains of Paradise (1979) +2010: Odyssey Two (1982) +The Songs of Distant Earth (1986) +2061: Odyssey Three (1987) +Cradle (1988) (with Gentry Lee) +The Ghost from the Grand Banks (1990) +The Hammer of God (1993) +Richter 10 (1996) (with Mike McQuay) +3001: The Final Odyssey (1997) +The Trigger (1999) (with Michael P. Kube-McDowell) +The Light of Other Days (2000) (with Stephen Baxter) +The Last Theorem (2008) (with Frederik Pohl) + +=== Short stories and short story collections === + +Travel by Wire! (1937) +How We Went to Mars (1938) +The Awakening (1942) +Loophole (1946) +Technical Error (1950) +Expedition to Earth (1953) +Reach for Tomorrow (1956) +Tales from the White Hart (1957) +The Other Side of the Sky (1958) +Tales of Ten Worlds (1962) +The Nine Billion Names of God (1967) +Of Time and Stars (1972) +The Wind from the Sun (1972) +The Best of Arthur C. Clarke (1973) +The Sentinel (1983) +Tales From Planet Earth (1990) +More Than One Universe (1991) +The Collected Stories of Arthur C. Clarke (2001) + +=== Non-fiction === +Interplanetary Flight: an introduction to astronautics (1950), London: Temple Press, ISBN 0-425-06448-4 +The Exploration of Space (1951), New York: Harper & Brothers +The Exploration of the Moon (1954), with R. A. Smith, New York: Harper Brothers +The Coast of Coral (1955), London: Frederick Muller +Boy Beneath the Sea (1958), New York: Harper, ISBN 0060212667 +Voice Across the Sea (1958), New York: Harper +Profiles of the Future: An Inquiry into the Limits of the Possible (1962), New York: Harper & Row +The Treasure of the Great Reef (1964), with Mike Wilson, New York: Harper & Row +Man and Space (1964), Life Science Library, New York: Time Life +Voices from the Sky: Previews of the Coming Space Age (1965), New York: Harper & Row +The Promise of Space (1968), New York: Harper & Row +Mars and the Mind of Man (1971), New York: Harper & Row ISBN 978-0-06-010443-6 +Report on Planet Three And Other Speculations (1972), New York: Berkley, ISBN 0-425-07592-3 +The View from Serendip (1977), New York: Random House, ISBN 0-394-41796-8 +1984: Spring / A Choice of Futures (1984), collected non-fiction writings, New York: Del Rey / Ballantine, ISBN 0-345-31357-7 +Astounding Days: A Science Fictional Autobiography (1989), London: Gollancz, ISBN 0-575-04446-2 +How the World Was One: Beyond the Global Village (1992), London: Gollancz, ISBN 0-575-05226-0 +Greetings, Carbon-Based Bipeds! : Collected Essays, 1934–1998 (1999), New York: St. Martin's Press, and London: Voyager + +== Media appearances == +The City in the Image of Man: Ideas and Work of Paolo Soleri (1972) +2010: The Odyssey Continues (1984) +The Day of Five Billion (1987) +Without Warning (1994) +Fractals: The colors of infinity (1995), narrated documentary +Future Fantastic (BBC, 1996) +Arthur C. Clarke: The Man Who Saw the Future (1997) +Odyssey of Survival (1999) +2001: HAL's Legacy (2001) +Stanley Kubrick: A Life in Pictures (2001) +To Mars by A-Bomb: The Secret History of Project Orion (BBC, 2003) +The Martians and Us (2006) +Planetary Defense (2007) +Vision of a Future Passed: The Prophecy of 2001 (2007) + +== Notes == + +== References == + +== External links == + +Official website of Arthur C. Clarke +Official website of the Arthur C. Clarke Foundation +"Sir Arthur C. Clarke biography". Science Fiction and Fantasy Hall of Fame. +Arthur C. Clarke (1917–2008) – International Astronautical Federation +Arthur C. Clarke at the Internet Speculative Fiction Database +Arthur C. Clarke at the Internet Book List +Arthur C. Clarke at IMDb +Sir Arthur C Clarke: 90th Birthday Reflections on YouTube +Works by or about Arthur C. Clarke at the Internet Archive +Works by Arthur C. Clarke at LibriVox (public domain audiobooks) +Works by Arthur C. Clarke at Open Library +"Arthur C. Clarke and Gentry Lee". Official transcript, Sci Fi Channel chat. 1 November 1996. Archived from the original on 1 December 2002. +Arthur C. Clarke Papers, Special Collections at the University of Southern Mississippi (de Grummond Children's Literature Collection) \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/BLC1-0.md b/data/en.wikipedia.org/wiki/BLC1-0.md index 6867577c4..ca38d5153 100644 --- a/data/en.wikipedia.org/wiki/BLC1-0.md +++ b/data/en.wikipedia.org/wiki/BLC1-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/BLC1" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:00:49.157998+00:00" +date_saved: "2026-05-05T13:15:44.019361+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Berserker_hypothesis-0.md b/data/en.wikipedia.org/wiki/Berserker_hypothesis-0.md index c2ddab0ae..1bf66c0d5 100644 --- a/data/en.wikipedia.org/wiki/Berserker_hypothesis-0.md +++ b/data/en.wikipedia.org/wiki/Berserker_hypothesis-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Berserker_hypothesis" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:59:05.161026+00:00" +date_saved: "2026-05-05T13:15:40.197990+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Biosignature-0.md b/data/en.wikipedia.org/wiki/Biosignature-0.md index cce2dd492..b95e3a774 100644 --- a/data/en.wikipedia.org/wiki/Biosignature-0.md +++ b/data/en.wikipedia.org/wiki/Biosignature-0.md @@ -4,7 +4,7 @@ chunk: 1/6 source: "https://en.wikipedia.org/wiki/Biosignature" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T07:15:15.960639+00:00" +date_saved: "2026-05-05T13:15:42.723741+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Biosignature-1.md b/data/en.wikipedia.org/wiki/Biosignature-1.md index d81fbd05d..904192bd5 100644 --- a/data/en.wikipedia.org/wiki/Biosignature-1.md +++ b/data/en.wikipedia.org/wiki/Biosignature-1.md @@ -4,7 +4,7 @@ chunk: 2/6 source: "https://en.wikipedia.org/wiki/Biosignature" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T07:15:15.960639+00:00" +date_saved: "2026-05-05T13:15:42.723741+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Biosignature-2.md b/data/en.wikipedia.org/wiki/Biosignature-2.md index 2a2af0023..56cac901c 100644 --- a/data/en.wikipedia.org/wiki/Biosignature-2.md +++ b/data/en.wikipedia.org/wiki/Biosignature-2.md @@ -4,7 +4,7 @@ chunk: 3/6 source: "https://en.wikipedia.org/wiki/Biosignature" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T07:15:15.960639+00:00" +date_saved: "2026-05-05T13:15:42.723741+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Biosignature-3.md b/data/en.wikipedia.org/wiki/Biosignature-3.md index a552a4b56..8c742dc7a 100644 --- a/data/en.wikipedia.org/wiki/Biosignature-3.md +++ b/data/en.wikipedia.org/wiki/Biosignature-3.md @@ -4,7 +4,7 @@ chunk: 4/6 source: "https://en.wikipedia.org/wiki/Biosignature" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T07:15:15.960639+00:00" +date_saved: "2026-05-05T13:15:42.723741+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Biosignature-4.md b/data/en.wikipedia.org/wiki/Biosignature-4.md index aec0cc9f8..a9f653f43 100644 --- a/data/en.wikipedia.org/wiki/Biosignature-4.md +++ b/data/en.wikipedia.org/wiki/Biosignature-4.md @@ -4,7 +4,7 @@ chunk: 5/6 source: "https://en.wikipedia.org/wiki/Biosignature" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T07:15:15.960639+00:00" +date_saved: "2026-05-05T13:15:42.723741+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Biosignature-5.md b/data/en.wikipedia.org/wiki/Biosignature-5.md index 0380e1424..725af6fcb 100644 --- a/data/en.wikipedia.org/wiki/Biosignature-5.md +++ b/data/en.wikipedia.org/wiki/Biosignature-5.md @@ -4,7 +4,7 @@ chunk: 6/6 source: "https://en.wikipedia.org/wiki/Biosignature" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T07:15:15.960639+00:00" +date_saved: "2026-05-05T13:15:42.723741+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Bracewell_probe-0.md b/data/en.wikipedia.org/wiki/Bracewell_probe-0.md new file mode 100644 index 000000000..603e5773f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Bracewell_probe-0.md @@ -0,0 +1,83 @@ +--- +title: "Bracewell probe" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Bracewell_probe" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:46.512351+00:00" +instance: "kb-cron" +--- + +Proposed by Ronald N. Bracewell in 1960, a Bracewell probe is defined as a hypothetical autonomous interstellar space probe designed for communication with alien civilizations. It offers a potential solution to the inherent challenges of interstellar radio communication, such as signal delay, synchronization, and detection over vast distances. + + +== Description == +A Bracewell probe is defined as an autonomous robotic interstellar space probe with advanced AI, pre-loaded with information or data its creators wish to convey. It would seek out existing technological civilizations or monitor worlds where such civilizations are likely to arise, establishing contact, making its presence known, conducting a dialogue over short distances (compared to interstellar distances), and transmitting the results of this interaction back to its origin. In essence, such probes would act as autonomous local representatives of their home civilization and serve as the point of contact between the cultures. +In contrast to radio communication across interstellar distances, a Bracewell probe offers key advantages: sustained presence in a target star system, active search capabilities, high-bandwidth local communication, and direct observation. Its physical presence serves as an unambiguous message. However, the probe cannot communicate information beyond its pre-loaded memory or update its contact protocols remotely. This inflexibility risks obsolescence and limits responses to unforeseen situations. Additionally, designing a Bracewell probe requires anticipating diverse alien biologies, psychologies, and technological levels — an inherently challenging task. +While a Bracewell probe does not need to be a von Neumann probe as well, the two concepts are compatible, and a self-replicating device as proposed by von Neumann would greatly speed up a Bracewell probe's search for alien civilizations. +It is also possible that such a probe (or system of probes if launched as a von Neumann–Bracewell probe) may outlive the civilization that created and launched it. +The search for Bracewell probes falls under SETA (Search for Extraterrestrial Artifacts) and SETV (Search for Extraterrestrial Visitation), encompassing efforts to detect evidence of extraterrestrial activity within the Solar System or nearby space. Detection methods might include searching for anomalous objects or emissions, analyzing long-delayed radio echoes (LDEs), and observing gravitational microlensing events. The LDE connection, however, remains highly speculative. These efforts often overlap with broader SETI initiatives, such as Breakthrough Listen. +The near-Earth object 1991 VG was initially considered a possible Bracewell probe due to its unusual rotation and orbit. However, subsequent observations identified it as a natural asteroid, with its characteristics attributed to the Yarkovsky effect and other non-gravitational forces. + + +== Variations == +Bracewell's original 1960 paper proposed an autonomous probe for interstellar communication, but later researchers and science fiction writers have expanded on this idea. + + +=== Messenger probes === +Following Bracewell’s original vision, these autonomous explorers carry pre-loaded messages and are designed to establish contact with technological civilizations. + + +=== Fly-through and rendezvous === +Some are built for high-speed travel, gathering data during brief encounters before transmitting their findings home. Others are designed to decelerate and enter orbit, allowing for prolonged observation and near-real-time communication. + + +=== Non-replicating and self-replicating === +While some remain singular, self-contained explorers, others incorporate von Neumann's concept of replication, enabling them to multiply and extend their search range exponentially. + + +=== Communicative and berserker === +Certain probes act as peaceful electronic ambassadors, fostering interstellar dialogue. Speculative berserker machines, rooted in science fiction, are envisioned as autonomous weapons capable of eradicating alien civilizations. + + +== Fictional examples == +In Arthur C. Clarke's 1979 novel The Fountains of Paradise the extraterrestrial Starglider probe is an example of a Bracewell probe. In Clarke's 1951 story "The Sentinel", later adapted into the 1968 film 2001: A Space Odyssey, the 'Monolith' appears to be a Bracewell probe placed on the Moon to ensure that only a civilization capable of spaceflight would be able to discover it. +Alien Planet is a 2005 94-minute Discovery Channel special about two internationally-built robot probes, and their mothership, searching for alien life on the fictional planet Darwin IV. +Bracewell probes are featured in David Brin's 2012 novel Existence. +In Star Trek: The Motion Picture (1979), a Voyager-class probe was upgraded and repurposed by an alien civilization. It acquired so much information, it became conscious and returned "home" to share what it learned +In the 1992 Star Trek: The Next Generation episode "The Inner Light", a Bracewell probe transmits details of an extinct civilization to Captain Picard. +In the 2001 Star Trek: Voyager episode "Friendship One", the crew is tasked with recovering a Bracewell probe that humans launched and find it on a planet whose inhabitants used the knowledge they obtained from it with disastrous results. +An alien probe contacts the space station Babylon 5 in the season 3 episode "A Day in the Strife". The probe disguises itself as a Bracewell probe, asking a series of questions and offering new technologies, medicine and science in return for answers to said questions. However, it's discovered that the probe was actually a berserker probe that would destroy any civilization that gave it correct answers by detonating an internal 500 megaton warhead. +The Snark, an alien probe that visits Earth in the novel In the Ocean of Night (1977) by Gregory Benford. +Bracewell probes in the role-playing game Eclipse Phase infect the seed AIs created by humanity with a deadly computer virus. +In the 2010 Doctor Who episode "Victory of the Daleks", the Daleks create a Bracewell probe in the form of a convincingly human android (appropriately named Bracewell) and covertly send it to Earth during World War II in order to communicate a false cover story to humans that disguises the Daleks' own arrival. + + +== See also == +Astrobiology – Science concerned with life in the universe +Breakthrough Initiatives – Science-based program founded in 2015 +Drake equation – Estimate of extraterrestrial civilizations +Extraterrestrial life – Life that does not originate on Earth +Fermi paradox – Discrepancy of the lack of evidence for alien life despite its apparent likelihood +First contact (science fiction) – Science fiction theme about the first meeting between humans and extraterrestrial life +Great Filter – Hypothesis of barriers to forming interstellar civilizations +Interstellar communication – Communication between planetary systems +Interstellar probe – Space probe that can travel out of the Solar System +Kardashev scale – Measure of a civilization's evolution +Project Daedalus – 1970s proposal for an interstellar probe +Self-replicating spacecraft – Space exploration concept +SETI Institute – Not-for-profit research organization +Technosignature – Property that provides scientific evidence for the presence of technology + + +== References == + +Bracewell, R. N. (1973). "The Opening Message from an Extraterrestrial Probe". Astronautics & Aeronautics. 11: 58–60. +McCollum, M. (1983). LifeProbe. New York: Ballantine Books. +Freitas Jr., R.A.; Valdes, F. (1985). "The Search for Extraterrestrial Artifacts". Acta Astronautica. 12 (12): 1027–1034. Bibcode:1985AcAau..12.1027F. CiteSeerX 10.1.1.118.4668. doi:10.1016/0094-5765(85)90031-1. + + +== External links == +Biographical entry for Ronald Bracewell at The Encyclopedia of Astrobiology, Astronomy, and Spaceflight +Bracewell probes, also at The Encyclopedia of Astrobiology, Astronomy, and Spaceflight +SETV projects \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Breakthrough_Initiatives-0.md b/data/en.wikipedia.org/wiki/Breakthrough_Initiatives-0.md new file mode 100644 index 000000000..35d78d502 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Breakthrough_Initiatives-0.md @@ -0,0 +1,66 @@ +--- +title: "Breakthrough Initiatives" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Breakthrough_Initiatives" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:48.823530+00:00" +instance: "kb-cron" +--- + +Breakthrough Initiatives is a science-based program founded in 2015 and funded by Julia and Yuri Milner, also of Breakthrough Prize, to search for extraterrestrial intelligence over a span of at least 10 years. The program is divided into multiple projects. Breakthrough Listen will comprise an effort to search over 1,000,000 stars for artificial radio or laser signals. A parallel project called Breakthrough Message is an effort to create a message "representative of humanity and planet Earth". The project Breakthrough Starshot, co-founded with Mark Zuckerberg, aims to send a swarm of probes to the nearest star at about 20% the speed of light. The project Breakthrough Watch aims to identify and characterize Earth-sized, rocky planets around Alpha Centauri and other stars within 20 light years of Earth. Breakthrough plans to send a mission to Saturn's moon Enceladus, in search for life in its warm ocean, and in 2018 signed a partnership agreement with NASA for the project. + + +== History == +The Breakthrough Initiatives were announced to the public on 20 July 2015, at London's Royal Society by physicist Stephen Hawking. Russian tycoon Yuri Milner created the Initiatives to search for intelligent extraterrestrial life in the Universe and consider a plan for possibly transmitting messages out into space. +The announcement included an open letter co-signed by multiple scientists, including Hawking, expressing support for an intensified search for alien radio communications. During the public launch, Hawking said: "In an infinite Universe, there must be other life. There is no bigger question. It is time to commit to finding the answer." +The US$100 million cash infusion is projected to mark up the pace of SETI research over the early 2000s rate, and will nearly double the rate NASA was spending on SETI research annually in approximately 1973–1993. + + +== Projects == + + +=== Breakthrough Listen === + +Breakthrough Listen is a program to search for intelligent extraterrestrial communications in the Universe. With $100 million in funding and thousands of hours of dedicated telescope time on state-of-the-art facilities, it is the most comprehensive search for alien communications to date. The project began in January 2016, and is expected to continue for 10 years. +The project uses radio wave observations from the Green Bank Observatory and the Parkes Observatory, and visible light observations from the Automated Planet Finder. Targets for the project include one million nearby stars and the centers of 100 galaxies. All data generated from the project are available to the public, and SETI@Home is used for some of the data analysis. The first results were published in April 2017, with further updates expected every 6 months. + + +=== Breakthrough Message === +The Breakthrough Message program is to study the ethics of sending messages into deep space. It also launched an open competition with a US$1 million prize pool, to design a digital message that could be transmitted from Earth to an extraterrestrial civilization. The message should be "representative of humanity and planet Earth". The program pledges "not to transmit any message until there has been a global debate at high levels of science and politics on the risks and rewards of contacting advanced civilizations". + + +=== Breakthrough Starshot === + +Breakthrough Starshot, announced 12 April 2016, is a US$100 million program to develop a proof-of-concept light sail spacecraft fleet capable of making the journey to Alpha Centauri at 20% the speed of light (60,000 km/s or 215 million km/h) taking about 20 years to get there, and about 4 years to notify Earth of a successful arrival. +The interstellar journey may include a flyby of Proxima Centauri b, an Earth-sized exoplanet that is in the habitable zone of its host star in the Alpha Centauri system. From a distance of 1 Astronomical Unit (150 million kilometers or 93 million miles), the four cameras on each of the spacecraft could potentially capture an image of high enough quality to resolve surface features. The spacecraft fleet would have 1000 craft, and each craft, named StarChip, would be a very small centimeter-sized craft weighing several grams. They would be propelled by several ground-based lasers of up to 100 gigawatts. Each tiny spacecraft would transmit data back to Earth using a compact on-board laser communications system. Pete Worden is the head of this project. The conceptual principles to enable this interstellar travel project were described in "A Roadmap to Interstellar Flight", by Philip Lubin of UC Santa Barbara. METI president Douglas Vakoch summarized the significance of the project, saying that "by sending hundreds or thousands of space probes the size of postage stamps, Breakthrough Starshot gets around the hazards of spaceflight that could easily end a mission relying on a single spacecraft. Only one nanocraft needs to make its way to Alpha Centauri and send back a signal for the mission to be successful. When that happens, Starshot will make history." +In July 2017, scientists announced that precursors to StarChip, named Sprites, were successfully launched and flown. + + +=== Breakthrough Watch === +Breakthrough Watch is a multimillion-dollar astronomical program to develop Earth- and space-based technologies that can find Earth-like planets in our cosmic neighborhood – and try to establish whether they host life. The project aims to identify and characterize Earth-sized, rocky planets around Alpha Centauri and other stars within 20 light years of Earth, in search of oxygen and other "biosignatures." + + +=== Breakthrough Enceladus === + +Breakthrough Enceladus is an astrobiology space probe mission concept to explore the possibility of life on Saturn's moon, Enceladus. In September 2018, NASA signed a collaboration agreement with Breakthrough to jointly create the mission concept. This mission would be the first privately funded deep space mission. It would study the content of the plumes ejecting from Enceladus's warm ocean through its southern ice crust. Enceladus's ice crust is thought to be around two to five kilometers thick, and a probe could use an ice-penetrating radar to constrain its structure. + + +== See also == + + +== References == + + +== External links == +Breakthrough Initiatives web site +Breakthrough Listen +Breakthrough Message +Yuri Milner and Stephen Hawking announce $100 million Breakthrough Initiative to dramatically accelerate search for intelligent life in the Universe / Breakthrough Initiatives, London, 20 July 2015 +Breakthrough Listen, Breakthrough Initiatives website +Breakthrough Initiatives' official website +Launching a StarChip – concept on YouTube +Going interstellar (NASA) on YouTube +Will Starshot's Insterstellar Journey Succeed? (PBS Digital Studios) on YouTube +Official website +Creation of Stephen Hawking's Universe with Nanotechnology \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Breakthrough_Listen-0.md b/data/en.wikipedia.org/wiki/Breakthrough_Listen-0.md new file mode 100644 index 000000000..f3fb908c7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Breakthrough_Listen-0.md @@ -0,0 +1,42 @@ +--- +title: "Breakthrough Listen" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Breakthrough_Listen" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:50.045436+00:00" +instance: "kb-cron" +--- + +Breakthrough Listen is an astronomy project to search for intelligent extraterrestrial communications. With $100 million in funding and thousands of hours of dedicated telescope time on state-of-the-art facilities, it is the most comprehensive search for alien communications to date. The project began in January 2016, and is expected to continue for 10 years. It is a component of Yuri Milner's Breakthrough Initiatives program. The science program for Breakthrough Listen is based at Berkeley SETI Research Center, located in the Astronomy Department at the University of California, Berkeley. +The project uses radio wave observations from the Green Bank Observatory and the Parkes Observatory, and visible light observations from the Automated Planet Finder. Targets for the project include one million nearby stars and the centers of 100 galaxies. All data generated from the project are available to the public, and SETI@Home (BOINC) is used for some of the data analysis. The first results were published in April 2017, with further updates expected every 6 months. + +== Overview == +The project aims to discover signs of extraterrestrial civilizations by searching stars and galaxies for radio signals and laser transmissions. The search for radio signals is carried out on the Green Bank Telescope in the Northern Hemisphere and the Parkes Telescope in the Southern Hemisphere. The Green Bank Telescope is the world's largest steerable radio telescope, and the Parkes Telescope is the second-largest steerable radio telescope in the Southern Hemisphere. +Together, the radio telescopes will cover ten times more sky than previous searches and scan the entire 1-to-10 GHz range, the so-called "quiet zone" in the spectrum where radio waves are unobscured by cosmic sources or Earth's atmosphere. +The radio telescopes are sensitive enough to detect "Earth-leakage" levels of radio transmission from stars within 5 parsecs, and can detect a transmitter of the same power as a common aircraft radar from the 1,000 nearest stars. The Green Bank Telescope began operations in January 2016, and the Parkes Telescope from October 2016. The FAST radiotelescope in China also joined forces in October 2016 with the Breakthrough Initiatives to launch a coordinated search, including the rapid sharing of promising new signals for additional observation and analysis. +The search for optical laser transmissions is carried out by the Automated Planet Finder of Lick Observatory. The telescope has the sensitivity to detect a 100 watt laser from a star 25 trillion miles (4.25 light years) away. + +== Announcement == + +Breakthrough Listen was announced to the public on July 20, 2015 (the anniversary of the Apollo 11 Moon landing) by Milner at London's Royal Society. The event was flanked by scientists such as Frank Drake, who is known for the Drake equation that estimates the number of detectable alien civilizations, and Geoff Marcy, an astronomer who has helped find hundreds of exoplanets. The announcement included an open letter co-signed by multiple scientists, including physicist Stephen Hawking, expressing support for an intensified search for alien life. During the public launch, Hawking said: + +In an infinite Universe, there must be other life. There is no bigger question. It is time to commit to finding the answer. + +== Significance == +The project is the most comprehensive search for alien communications to date. It is estimated that the project will generate as much data in one day as previous SETI projects generated in one year. Compared to previous programs, the radio surveys cover 10 times more of the sky, at least 5 times more of the radio spectrum, and work 100 times faster. The optical laser survey is also the deepest and broadest search in history. +Andrew Siemion, director of the Berkeley SETI Research Center at the University of California, Berkeley, describes that "We would typically get 24–36 hours on a telescope per year, but now we'll have thousands of hours per year on the best instruments...It's difficult to overstate how big this is. It's a revolution." + +== Targets == +As of April 2016, the targets for the radio search with the Green Bank Radio Telescope in the Northern Hemisphere include the following: + +All 43 stars within 5 parsec, or 16.3 light-years, or 1.03 million astronomical units, or 1.545×1014 kilometres +1000 stars of all spectral-types within 50 pc, or 163 ly, or 10.3 million au, or 1.545×1015 km +One million nearby stars +Center regions of at least 100 nearby galaxies, including spiral galaxies, elliptical galaxies, dwarf galaxies and irregular galaxies +Exotic stars: 20 white dwarfs, 20 neutron stars, 20 black holes +The Parkes Radio Telescope will cover similar targets in the Southern Hemisphere from 1–4 GHz, and also the galactic plane and center. +The targets for the Automated Planet Finder will closely match those of the Green Bank radio search, with small adjustments due to the telescope's much smaller field of view. +While the telescopes are observing, the current targets of the Green Bank Radio Telescope and the Automated Planet Finder can be viewed live at the Berkeley Seti Research Center. +In January 2017, the project published its initial targets, which are the 60 nearest stars and a further 1649 stars which are the closest representatives of each spectral type. The initial targets also include 123 galaxies which cover all morphological types of galaxies. +In October 2019 it was announced that Breakthrough Listen will collaborate with scientists from NASA's Transiting Exoplanet Survey Satellite (TESS) team. Over a thousand new planets found by TESS will be scanned for technosignatures. The search will use Listen's primary facilities (Green Bank and Parkes Telescopes, MeerKAT, and the Automated Planet Finder) as well as partner facilities (including VERITAS, NenuFAR, FAST, the Murchison Widefield Array, LOFAR stations in Ireland and Sweden, Jodrell Bank Observatory, e-MERLIN, Keck Observatory, Sardinia Radio Telescope, along with the Allen Telescope Array). In addition to targeting of TESS planets with Listen facilities, the TESS lightcurves themselves will be searched for anomalies, for example caused by megastructures. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Breakthrough_Listen-1.md b/data/en.wikipedia.org/wiki/Breakthrough_Listen-1.md new file mode 100644 index 000000000..4d5d89aa4 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Breakthrough_Listen-1.md @@ -0,0 +1,40 @@ +--- +title: "Breakthrough Listen" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Breakthrough_Listen" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:50.045436+00:00" +instance: "kb-cron" +--- + +== Breakthrough Listen Exotica Catalog == +Breakthrough Listen Exotica Catalog is a list of 700 targets that were chosen "to include "one of everything" in the observed Universe – ranging from comets to galaxies, from mundane objects to the most rare and violent celestial phenomena". +There are four types of targets in the catalog: + +"Prototypes: a list containing at least one example of every known kind of celestial object (apart from those too transient to present realistic observation targets). Planets and moons, stars at every point of their life cycle, galaxies big and small, serene star clusters and blazing quasars, and more are all included in the list." +"Superlatives: objects with the most extreme properties. These include examples like the hottest planet, stars with unusually high or low metal content, the most distant quasar and fastest-spinning pulsar, and the densest galaxy." +"Anomalies: enigmatic targets whose behavior is currently not satisfactorily explained. For instance, the famous "Tabby's Star" with its bizarre dimming behavior; ʻOumuamua – the interstellar object that passed near Earth in 2017; unexplained optical pulses that last mere nanoseconds; and stars with excess infrared radiation that could conceivably be explained as waste heat from alien megastructures." +A control sample of sources not expected to produce positive results. + +== Data processing == +Analyzing radio observations for possible signals requires intensive data analysis to cover all of the possible signal types. To carry out an in-depth search, the data recorder at the Green Bank telescope has been significantly upgraded. The system records 6 GHz of bandwidth at 24GB of data per second, making it among the highest data rate recording systems in radio astronomy, and there is a plan to double its capabilities in the near future. Once this data has been recorded, it is analysed for signals using a computing cluster with 64 GTX 1080 GPUs. The raw data is reduced to a lower resolution to allow long-term storage, but even this reduced data totals approximately 1 petabyte per year. +All data generated from Breakthrough Listen project will be open to the public. The data is uploaded on the initiative's Open Data Archive, where any user can download it for software analysis. Breakthrough Initiatives are developing open source software to assist users in understanding and analyzing the data, which are available on GitHub under UCBerkeleySETI. +The data is also processed by the SETI@home (BOINC) volunteer computer network, with the first batch of data being made available to SETI@home in April 2016. + +== Funding == +The project is funded with $100 million from the foundation co-founded by Yuri Milner. One third of this funding will be used to purchase telescope time. So far, the project has signed contracts for around 20 percent of the time on the Green Bank Telescope for the next five years, and 25 percent of the time on the Parkes Telescope. Another third will be used for the development of new equipment to receive and process potential signals, and the final third will be used to hire astronomy staff. + +== Project leadership == +Among the projects leaders are: + +Frank Drake, chairman emeritus, SETI Institute; professor emeritus of astronomy and astrophysics, University of California, Santa Cruz; founding director, National Astronomy and Ionosphere Center; former Goldwin Smith Professor of Astronomy, Cornell University. +Ann Druyan, creative director of the Voyager Interstellar Message, NASA Voyager; co-founder and CEO, Cosmos Studios; Emmy Award- and Peabody Award-winning writer and producer. +Martin Rees, Astronomer Royal, Fellow of Trinity College; emeritus professor of cosmology and astrophysics, University of Cambridge. +Andrew Siemion, director, Berkeley SETI Research Center. +Dan Werthimer, co-founder and chief scientist of the SETI@home project; director of SERENDIP; principal investigator for CASPER. +Pete Worden, chairman, Breakthrough Prize Foundation. + +== Results == +In April 2017, the project released its first set of results, covering the observations of 692 nearby stars at frequencies from 1.1–1.9 GHz (the L-band). These observations included 11 events which passed the threshold for significance, but it was concluded that they were all consistent with radio frequency interference. A summary of the observations and the raw data relating to them has been published online. The project plans to continue publishing updated results approximately every 6 months. +The project has begun at lower frequencies as these have a lower frequency range which is easier to record and process, and plans eventually to observe in a wide range of frequencies from 1.15 GHz to 93 GHz. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Breakthrough_Listen-2.md b/data/en.wikipedia.org/wiki/Breakthrough_Listen-2.md new file mode 100644 index 000000000..c32dcf5ab --- /dev/null +++ b/data/en.wikipedia.org/wiki/Breakthrough_Listen-2.md @@ -0,0 +1,33 @@ +--- +title: "Breakthrough Listen" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Breakthrough_Listen" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:50.045436+00:00" +instance: "kb-cron" +--- + +On August 30, 2017, Breakthrough Listen said it picked a series of 15 radio bursts coming from a dwarf galaxy about 3 billion light years away. Breakthrough Listen researchers said the possibility of the source being extraterrestrial life cannot yet be ruled out. The radio emissions were detected by the Green Bank Telescope in West Virginia. The source is FRB 121102 which was already known but the activity was vastly different in the latest findings. +In December 2017, Breakthrough Listen observed ʻOumuamua, an interstellar asteroid with an unusually elongated shape, for any signs of radio emissions. Over eight hours of observing over a range of frequencies from 1.1–11.6 GHz, no emissions were detected. +In December 2018, a search for laser light emissions from Boyajian's Star was carried out using the Automated Planet Finder, which is sensitive enough to detect a 24 MW laser at this distance. Although a number of candidates were identified, further analysis showed that they are coming from the Earth and not from the star. +In January 2020, a preliminary results for the nearby (<150 parsecs away) stars were announced, with no positive detections of artificial transmitters comparable to the terrestrial Arecibo Observatory in the 3.95-8.00 GHz band. Also, it was concluded that at least 8% of 252 nearby stars in a zone allowing detection of Earth by occultation method do not have the 100%-duty (artificial) transmitters of the sort sought by the survey. +In December 2020, it was reported that in April and May 2019, a narrowband signal at 982.002 MHz was intercepted that showed shifts in its frequency consistent with the movement of a planet. No modulation was detected. The signal appears to have originated from the direction of Proxima Centauri. It has been given the name Breakthrough Listen Candidate 1 (BLC1). As of December 2020, the researchers were still working to rule out terrestrial interference, which they considered the most likely cause. One researcher called it "on par" with the Wow! signal. +In May 2022, Breakthrough Listen conducted the first targeted search for the Wow! Signal. It was its first collaboration between the Green Bank Telescope and the SETI Institute's Allen Telescope Array. The observations lasted 1 hour from Greenbank, 35 minutes from ATA, and 10 minutes simultaneously. No technosignature candidates were found. + +== See also == + +Communication with extraterrestrial intelligence +Detecting Earth from distant stars – Detecting Earth as an exoplanetPages displaying short descriptions of redirect targets +List of nearest stars and brown dwarfs within 20 light years +Nexus for Exoplanet System Science +Ohio State University Radio Observatory +Open data, Open-source software +Search for extraterrestrial intelligence +SETI Institute + +== References == + +== External links == +Breakthrough Listen, Breakthrough Initiatives website +Berkeley SETI Research Center, Berkeley SETI Research Center website \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Brian_Binnie-0.md b/data/en.wikipedia.org/wiki/Brian_Binnie-0.md new file mode 100644 index 000000000..a03b764d6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Brian_Binnie-0.md @@ -0,0 +1,40 @@ +--- +title: "Brian Binnie" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Brian_Binnie" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:19.002542+00:00" +instance: "kb-cron" +--- + +William Brian Binnie (April 26, 1953 – September 15, 2022) was a United States Navy officer and one of the test pilots for SpaceShipOne, the experimental spaceplane developed by Scaled Composites and flown from 2003 to 2004. + + +== Early life == + +Binnie was born in West Lafayette, Indiana, on April 26, 1953, where his Scottish father William P. Binnie was a professor of physics at Purdue University. The family returned to Scotland when Binnie was five, and lived in Aberdeen (his father taught at Aberdeen University) and later in Stirling. When Binnie was a teenager the family moved to Boston. +Binnie earned a bachelor's degree in aerospace engineering from Brown University. He earned a master's degree from Brown in fluid mechanics and thermodynamics. Binnie was rejected by the United States Air Force, and enrolled at Princeton University, where he earned a master's degree in mechanical and aerospace engineering He served for 21 years in the United States Navy as a naval aviator, reaching the rank of commander. He flew the LTV A-7 Corsair II, Grumman A-6 Intruder, McDonnell Douglas F/A-18 Hornet, and McDonnell Douglas AV-8B Harrier II. He graduated from the United States Naval Test Pilot School in 1988. Binnie also copiloted the Atmospheric Test Vehicle of the Rotary Rocket. In 2006, he received an honorary degree from the University of Aberdeen. + + +== SpaceShipOne and spaceflight == + +On December 17, 2003, the 100th anniversary of the Wright brothers' first powered flight, Binnie piloted the first powered test flight of SpaceShipOne, flight 11P, which reached a top speed of Mach 1.2 and a height of 12.9 miles (20.7 km). On October 4, 2004, he piloted SpaceShipOne's second Ansari X Prize flight, flight 17P, winning the X Prize and becoming the 436th person to go into space. His flight, which peaked at 367,442 feet (69.6 mi; 112.0 km), set a winged aircraft altitude record for suborbital flights, breaking the old record set by the North American X-15 in 1963. It also earned him the second Astronaut Badge to be given by the Federal Aviation Administration for a flight aboard a privately operated commercial spacecraft. + + +== Later career == +In 2014 Binnie joined XCOR Aerospace as senior engineer and test pilot, after working as a test pilot and program business manager for Scaled Composites for many years. + + +== Personal life == +Binnie and his wife, Bub, had three children. +Binnie died on September 15, 2022, at age 69. + + +== References == + + +== External links == + +Biography at Scaled Composites website +Biography at SpaceFacts.de \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/CTA-102-0.md b/data/en.wikipedia.org/wiki/CTA-102-0.md new file mode 100644 index 000000000..2e17424e5 --- /dev/null +++ b/data/en.wikipedia.org/wiki/CTA-102-0.md @@ -0,0 +1,25 @@ +--- +title: "CTA-102" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/CTA-102" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:58.610721+00:00" +instance: "kb-cron" +--- + +CTA 102, also known by its B1950 coordinates as 2230+114 (QSR B2230+114) and its J2000 coordinates as J2232+1143 (QSO J2232+1143), is a blazar-type quasar discovered in the early 1960s by a radio survey carried out by the California Institute of Technology. It has been observed by a large range of instruments since its discovery, including WMAP, EGRET, GALEX, VSOP and Parkes, and has been regularly imaged by the Very Long Baseline Array since 1995. It has also been detected in gamma rays, and a gamma-ray flare has been detected from it. +In 1963 Nikolai Kardashev proposed that the then-unidentified radio source could be evidence of a Type II or III extraterrestrial civilization on the Kardashev scale. Follow-up observations were announced in 1965 by Gennady Sholomitskii, who found that the object's radio emission was varying; a public announcement of these results on April 12, 1965, caused a worldwide sensation. The idea that the emission was caused by a civilization was rejected when the radio source was later identified as one of the many varieties of a quasar. +The American folk rock band The Byrds whimsically reflected the original view that CTA-102 was a sign of extraterrestrial intelligence in their song "C.T.A.-102" from their 1967 album Younger Than Yesterday. +In late 2016 CTA 102, usually glowing around magnitude +17, had a bright outburst in visible light to magnitude +11 (~250 times brighter than usual). This likely was the most luminous blazar state ever observed, with an absolute magnitude in excess of -32. +A new outburst began in December 2017, with increased gamma-ray and optical activity. As of 22 December 2017, it has reached magnitude +14. +CTA 102 displays a radio structure mainly made of a radio core and two other components. There is also a double knot feature. Additionally, it also has two radio lobes described having flux densities of 170 and 75 mJy, with a jet found as curved according to high resolution imaging by Very Long Baseline interferometry at 15 GHz. This jet contains jet components moving with apparent velocities of 15.4 ± 0.9c. +The quasar is also classified to be highly polarized with a flat radio spectrum, and such belongs to a classification of optically violent variable quasars. + + +== See also == +PSR B1919+21, the first pulsar discovered, mistaken for an alien radio signal +HD 164595 + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Charles_Stuart_Bowyer-0.md b/data/en.wikipedia.org/wiki/Charles_Stuart_Bowyer-0.md new file mode 100644 index 000000000..25818314a --- /dev/null +++ b/data/en.wikipedia.org/wiki/Charles_Stuart_Bowyer-0.md @@ -0,0 +1,50 @@ +--- +title: "Charles Stuart Bowyer" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Charles_Stuart_Bowyer" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:45.299365+00:00" +instance: "kb-cron" +--- + +Charles Stuart Bowyer (August 2, 1934 – September 23, 2020) was an American astronomer and academic. He was a professor at the University of California. + + +== Early life and education == +Bowyer was born in Toledo, Ohio, to Howard and Elizabeth Bowyer. His father was a pilot. As a boy, he attended a one-room grade school near his father’s farm in Orland Park, Ill., before being valedictorian at Orland Park High School. He graduated from Miami University of Ohio with a degree in physics. He received his Ph.D. in physics from Catholic University in 1965. + + +== Career == +Bowyer was a professor at University of California at Berkeley. He was also affiliated with the United States Naval Research Laboratory. He worked in a group directed by Herbert Friedman. He is generally given credit for starting the field of extreme ultraviolet astronomy. Bowyer’s pursuit of studying ultraviolet rays was met with resistance at first - astronomers argued that even outside of the Earth's atmosphere most ultraviolet light would get absorbed and be undetectable. However, in 1975 when Bowyer and his team mounted a sensor on Apollo–Soyuz, they were able to detect ultraviolet radiation from white dwarfs and a nova. +He is credited with shepherding the launch of the EUVE satellite and subsequent research activities. The EUVE launched in 1992 and circled Earth for nine years, cataloging about 800 EUV sources in the Milky Way galaxy, before losing operating funds and shutting down in 2001. +Bowyer was also active in the search for extraterrestrial intelligence, or SETI. In 1977, Bowyer started SERENDIP (the Search for Extraterrestrial Radio Emissions From Nearby Developed Intelligent Populations) using an 85-foot telescope at Hat Creek Radio Observatory near Lassen Peak in Northern California. The project was inspired by Project Cyclops, a 1971 NASA report that proposed an international network of radio telescopes to search for intelligent life in the universe. SERENDIP was designed to operate in the background of other astronomers' radio observations. While those observations were happening, it would scan 100 radio frequencies simultaneously in search of extraterrestrial emissions. The project was funded primarily by private donors, including writer and futurist Arthur C. Clarke. + + +== Death == +Bowyer died from complications of COVID-19 at an Orinda, California, hospital on September 23, 2020. He was 86. + + +== Selected works == +In a statistical overview derived from writings by and about Stuart Bowyer, OCLC/WorldCat encompasses roughly 30+ works in 40+ publications in 3 languages and 1,000+ library holdings. + +X-Ray Astronomy Observational Results, Theoretical Aspects and Experimental Procedures (1970) +Research in extreme ultraviolet and far ultraviolet astronomy semi-annual status report December 1, 1984 – May 31, 1985 (1985) +Research in extreme ultraviolet and far ultraviolet astronomy semi-annual status report June 1, 1986 – December 31, 1986 (1986) + + +== Honors == +Bowyer received the Humboldt Foundation of Germany Senior Scientist Award in 1982. Other honors and distinctions include the NASA Exceptional Technical Achievement Medal, the NASA Exceptional Scientific Achievement Medal, the Alexander von Humboldt Foundation’s Humboldt Prize, an honorary doctor of science degree from Miami University of Ohio, an honorary doctor of philosophy degree from the Catholic University of America, the NASA Distinguished Public Service Medal, the Computerworld Smithsonian Award and the COSPAR Massey Award. + + +== Notes == + + +== References == +Margenau, Henry and Roy Abraham Varghese. (1992). Cosmos, Bios, Theos: Scientists Reflect on Science, God, and the Origins of the Universe, Life, and Homo Sapiens. LaSalle, Illinois: Open Court. ISBN 9780812691856; OCLC 231415341 + + +== External links == +Oral History interview transcript with Charles Stuart Bowyer on 28 July 1976, American Institute of Physics, Niels Bohr Library and Archives - Session I +Oral History interview transcript with Charles Stuart Bowyer on 10 March 1978, American Institute of Physics, Niels Bohr Library and Archives - Session II +Publication listings Archived 2012-02-16 at the Wayback Machine \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Chuck_Coleman-0.md b/data/en.wikipedia.org/wiki/Chuck_Coleman-0.md new file mode 100644 index 000000000..e7b8cf769 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Chuck_Coleman-0.md @@ -0,0 +1,44 @@ +--- +title: "Chuck Coleman" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Chuck_Coleman" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:20.239050+00:00" +instance: "kb-cron" +--- + +Charles Thomas Coleman (1962 or 1963 – October 20, 2024) was an American aviator, aerospace engineer and airshow & test pilot. He worked as a design and performance engineer for several aircraft corporations such as McDonnell Aircraft Corporation, Bede Jet Corporation and Scaled Composites. Coleman was a member of the Society of Experimental Test Pilots SETP as an Associate Fellow, and served on the board of directors for the Mojave Air and Space Port. As a commercial, test, and instructor pilot, he logged more than 10,800 hours of flight time. + + +== Early life and education == +Coleman was raised in St. Johns, Michigan, by Thomas Coleman and JoAnn (Benedict) Smith. He graduated from the University of Michigan in 1985 with a Bachelor's of Science in Aerospace/Mechanical Engineering. + + +== Career == +Coleman was a design engineer for 6 years at McDonnell Aircraft Corporation in St. Louis, Missouri. He was involved in military jet projects including serving as the Senior Design Engineer on the High Alpha Research Vehicle, a modified F/A-18 Hornet, utilized by NASA to investigate controlled flight at high angles of attack by way of thrust vectoring. +Coleman also served as a Senior Engineer on the F/A-18 conversion from combat-ready aircraft into performance planes for the United States Navy Blue Angels flight demonstration squadron. +He was a project engineer at the Bede Jet Corporation in Chesterfield, Missouri at the Spirit of St. Louis Airport. He served as the test pilot on the BD-10, a kit-built experimental jet aircraft, and BD-12, a two-seat experimental plane with a pusher configuration. +Coleman joined Scaled Composites in Mojave, California as a performance engineer, test pilot, and chase pilot in 2002. He was on a team of five engineers that designed, constructed, and flight tested the Virgin Atlantic GlobalFlyer, which was the first jet powered aircraft to fly around the world non-stop un-refueled. +Coleman was also a test pilot for the Proteus high altitude jet and tested the Tier One Navigation System for SpaceShipOne, as well as conducting high-G astronaut training for SpaceShipOne astronauts and serving as chase pilot for SpaceShipOne flights. Coleman also served as a test pilot for the ICON A5, an American amphibious light-sport aircraft. + + +== Performance == +Coleman performed at numerous airshows and flew aerobatic planes for Patty Wagstaff, Gene Soucy, Ian Groom, Tim Weber, Sean D. Tucker, Discovery Channel, Toyota Airsports, and Paramount Pictures. In 2018, Coleman trained the lead actors starring in Top Gun: Maverick featuring Tom Cruise, Val Kilmer, and Jennifer Connelly. Coleman conducted 140 G tolerance training flights in an Extra EA-300 with actors Glen Powell, Miles Teller, Monica Barbaro, Jay Ellis, Lewis Pullman, and Danny Ramirez, in a flight training regime designed by Cruise. These aerobatic flights were conducted in order to prepare the actors for flight in F/A-18F Super Hornets during actual filming. + + +== Death == +On October 20, 2024, Coleman died in a crash during the Las Cruces Air & Space Expo at Las Cruces International Airport. He was 61 years old. The crash occurred around 2:30 pm. Coleman was performing aerobatics when his Extra EA-300 plane crashed half a mile west of the airport. + + +== Awards == +Coleman won two Collier Trophies for his involvement in the development of the McDonnell Douglas C-17 Globemaster (1994) and Scaled Composites’ SpaceShipOne (2004). Coleman was also part of the Scaled Composites team that won the Ansari X Prize, a space competition in which the X Prize Foundation offered a cash prize for the first non-government organization to launch a reusable crewed spacecraft into space twice within two weeks. + + +== References == + + +== External links == + +Official website +Chuck Coleman at IMDb \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-0.md b/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-0.md index 274e4781d..448bc4dc9 100644 --- a/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-0.md +++ b/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-0.md @@ -4,7 +4,7 @@ chunk: 1/3 source: "https://en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:31.304973+00:00" +date_saved: "2026-05-05T13:15:54.987286+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-1.md b/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-1.md index 36d4a5059..06f5b9b34 100644 --- a/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-1.md +++ b/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-1.md @@ -4,7 +4,7 @@ chunk: 2/3 source: "https://en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:31.304973+00:00" +date_saved: "2026-05-05T13:15:54.987286+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-2.md b/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-2.md index db86a808e..9bdba966c 100644 --- a/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-2.md +++ b/data/en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence-2.md @@ -4,7 +4,7 @@ chunk: 3/3 source: "https://en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:31.304973+00:00" +date_saved: "2026-05-05T13:15:54.987286+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Contact_(novel)-0.md b/data/en.wikipedia.org/wiki/Contact_(novel)-0.md new file mode 100644 index 000000000..479ef5915 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Contact_(novel)-0.md @@ -0,0 +1,54 @@ +--- +title: "Contact (novel)" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Contact_(novel)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:56.176721+00:00" +instance: "kb-cron" +--- + +Contact is a 1985 hard science fiction novel by American scientist Carl Sagan. The plot concerns contact between humanity and a more technologically advanced extraterrestrial life form. +Contact ranked number seven on Publishers Weekly's 1985 bestseller list. The only full work of fiction published by Sagan, the novel originated as a screenplay by Sagan and Ann Druyan (whom he later married) in 1979; when development of the film stalled, Sagan converted it into a novel. It was adapted in 1997 as the film Contact, starring Jodie Foster. + + +== Plot == +As a child, Eleanor "Ellie" Arroway shows a strong aptitude for science and mathematics. Dissatisfied with a school lesson, she confirms in a library that pi is transcendental. In sixth grade, her father, Theodore ("Ted"), dies. Her new stepfather, John Staughton, does not support her interests. Ellie resents him and believes her mother remarried out of weakness. +After graduating from Harvard, Ellie earns a doctorate from Caltech under radio astronomer David Drumlin. She becomes director of "Project Argus," a New Mexico radio telescope array searching for extraterrestrial intelligence (SETI). This puts her at odds with much of the scientific community, including Drumlin, who pushes to defund SETI. Eventually, the project detects a signal from Vega, 26 light-years away, transmitting prime numbers. Further analysis reveals a retransmission of Adolf Hitler's 1936 Olympic speech, the first TV signal to escape Earth's ionosphere. +President Helen Lasker meets with Ellie to discuss first contact. Ellie begins a relationship with Presidential Science Advisor Ken der Heer. With Soviet colleague Vaygay Lunacharsky, she ensures continuous monitoring of the signal. A third message contains plans for an advanced machine, but decoding its 30,000 pages proves impossible without a missing primer. +At the President's insistence, Ellie meets religious leaders Billy Jo Rankin and Palmer Joss. A skeptic, she demonstrates her faith in science by trusting a Foucault pendulum. Dismissing Rankin's views, she finds Joss's perspective intriguing. In Paris, experts confirm the Machine is a five-seat dodecahedron. There, Ellie meets Devi Sukhavati, a doctor who lost her husband after leaving India for love. The final message piece is found when billionaire S. R. Hadden suggests checking for phase modulation, revealing the primer. +A U.S.–Soviet race to build the Machine ensues, but Soviet design flaws leave the American version as the only option. Ellie applies as a passenger but loses her spot to Drumlin. Extremists plant a bomb in the Wyoming facility, which detonates during testing, killing Drumlin and delaying the project indefinitely. Meanwhile, Ellie's mother suffers a stroke, leaving her paralyzed. Staughton accuses Ellie of neglecting her family. +Ellie later learns Hadden has moved to a private space station. There, he reveals his company has secretly built a third Machine in Hokkaido, Japan, set for launch on December 31, 1999. Ellie, Vaygay, and Devi secure seats, joined by Nigerian physicist Abonnema Eda and Chinese archaeologist Xi Qiaomu. Before departure, Joss gives Ellie a medallion, which she takes aboard. +The activated Machine transports the group through wormholes to a station near the Milky Way's center, where each meets an extraterrestrial in the form of a loved one. Ellie's visitor, appearing as Ted, explains their species' motives and a project to alter the universe's properties using mass in Cygnus A. The wormhole network was built by unknown precursors, and hidden messages exist in transcendental numbers like pi. Reunited, the travelers record evidence before the dodecahedron returns them to Earth. +Back home, their journey—seeming more than a day—took no time at all on Earth. Their video recordings are erased, likely by wormhole magnetic fields. With Hadden seemingly dead and the transmission halted, officials suspect a hoax. Pressured, the travelers stay silent, though Joss believes Ellie, who now relies on faith. Hadden faked his death, secretly launching himself into space using cryogenics, but this remains unknown to the characters. +Following "Ted's" suggestion, Ellie runs a program computing pi to unprecedented lengths. Before results emerge, her mother dies, leaving a final letter revealing Staughton—not Ted—is Ellie's biological father. When Ellie examines the program's output, she finds a circle formed from 0s and 1s after 1020 digits in pi's base-11 representation—evidence of her journey. + + +== Publication history == +Reading science fiction and fantasy as a child inspired Sagan to become an astronomer. As an adult, he preferred realistic stories that helped readers understand real science and history, like Robert Heinlein's "—And He Built a Crooked House—" and L. Sprague de Camp's Lest Darkness Fall. In 1978, Sagan predicted that because of science fiction, "I know many young people who would, of course, be interested, but in no way astounded, were we to receive a message tomorrow from an extraterrestrial civilization". In 1981, Simon & Schuster gave Sagan a $2 million advance on the novel. At the time, "the advance was the largest ever made for a book that had not yet been written." The first printing was 265,000 copies. In the first two years it sold 1,700,000 copies. It was a main selection of Book-of-the-Month-Club. +Sagan's friend, physicist Kip Thorne, gave Sagan ideas on the nature of wormholes when Sagan was developing the outline of the novel. +Sagan named the novel's protagonist, Eleanor Arroway, after two people: Eleanor Roosevelt, a "personal hero" of Sagan's wife, Ann Druyan, and Voltaire, whose last name was Arouet. The character is based on the real-life SETI researcher Jill Tarter. +In 1986, the novel won the Locus Award for Best First Novel, and placed #15 in the poll for the Locus Award for Best Science Fiction Novel. + + +== See also == + +Communication with extraterrestrial intelligence +Fermi paradox +His Master's Voice + + +== Notes == + + +== References == + + +== Sources == +Davidson, Keay. Carl Sagan: A Life. New York: John Wiley & Sons, 1999. +Sagan, Carl. Contact. New York: Simon and Schuster, 1985. +Spence, Jennifer. "20th-Century American Bestsellers: Contact". LIS 590AB/ENGL 564: 20th-Century American Bestsellers (Spring 2006). Graduate School of Library and Information Science, University of Illinois, Urbana-Champaign. Archived from the original on July 19, 2011. Retrieved August 18, 2010. + + +== External links == +Larry Klaes' in-depth analysis of the film and novel \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Cosmic_Call-0.md b/data/en.wikipedia.org/wiki/Cosmic_Call-0.md new file mode 100644 index 000000000..68547a3c7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Cosmic_Call-0.md @@ -0,0 +1,51 @@ +--- +title: "Cosmic Call" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Cosmic_Call" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:57.364030+00:00" +instance: "kb-cron" +--- + +Cosmic Call was the name of two sets of interstellar radio messages that were sent from RT-70 in Yevpatoria, Ukraine in 1999 (Cosmic Call 1) and 2003 (Cosmic Call 2) to various nearby stars. The messages were designed with noise-resistant format and characters. +The project was funded by Team Encounter, a Texas-based startup, which went out of business in 2004. +Both transmissions were at ~150 kW, 5.01 GHz (FSK +/-24 kHz). + + +== Message structure == +Each Cosmic Call 1 session had the following structure. The Scientific Part (DDM, BM, AM, and ESM) was sent three times (at 100 bit/s), and the Public Part (PP) was sent once (at 2000 bit/s), according to the following arrangement: + +DDM → BM → AM → ESM → DDM → BM → AM → ESM → DDM → BM → AM → ESM → PP, +where DDM is the Dutil-Dumas Message, created by Canadian scientists Yvan Dutil and Stéphane Dumas, BM is the Braastad Message, AM is the Arecibo Message, and ESM is the Encounter 2001 Staff Message. +Each Cosmic Call 2 session in 2003 had the following structure: + +DDM2 → DDM2 → DDM2 → AM → AM → AM → BIG → BIG → BIG → BM → ESM → PP, +where DDM2 is modernized DDM (aka Interstellar Rosetta Stone, ISR), BIG is Bilingual Image Glossary. All but the PP were transmitted at 400 bit/s +The ISR was 263,906 bits; BM, 88,687 bits, AM, 1,679 bits; BIG was 12 binary images 121,301 bits; ESM 24,899 bits. Total = 500,472 bits for 53 minutes. PP was 220 megabytes and sent at a rate of 100,000 bit/s for 11 hours total. + + +== Error in Cosmic Call 1 == +The DDM incorrectly gave the neutron mass as 1.67392, instead of the known value of 1.67492. This error was corrected in DDM2. + + +== Stars targeted == +The messages were sent to the following stars: + + +== See also == +Arecibo message +Active SETI +Communication with extraterrestrial intelligence +Interstellar messages + + +== References == + + +== External links == + +Self-Decoding Messages +Discussion of the Call's "Rosetta Stone" and how it was developed +Report on Cosmic Call +Evpatoria 2003 discussion with bitmap and image \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Dark_forest_hypothesis-0.md b/data/en.wikipedia.org/wiki/Dark_forest_hypothesis-0.md index 1ccc3aff6..228bd6074 100644 --- a/data/en.wikipedia.org/wiki/Dark_forest_hypothesis-0.md +++ b/data/en.wikipedia.org/wiki/Dark_forest_hypothesis-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Dark_forest_hypothesis" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:59:18.155821+00:00" +date_saved: "2026-05-05T13:16:01.002886+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/David_P._Anderson-0.md b/data/en.wikipedia.org/wiki/David_P._Anderson-0.md new file mode 100644 index 000000000..ab8253058 --- /dev/null +++ b/data/en.wikipedia.org/wiki/David_P._Anderson-0.md @@ -0,0 +1,53 @@ +--- +title: "David P. Anderson" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/David_P._Anderson" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:34.104416+00:00" +instance: "kb-cron" +--- + +David Pope Anderson (born 1955) is an American research scientist at the Space Sciences Laboratory, at the University of California, Berkeley, and an adjunct professor of computer science at the University of Houston. Anderson leads the SETI@home, BOINC, Bossa, and Bolt software projects. + + +== Education == +Anderson received a BA in mathematics from Wesleyan University, and MS and PhD degrees in mathematics and computer science from the University of Wisconsin–Madison. While in graduate school he published four research papers in computer graphics. His PhD research involved using enhanced attribute grammars to specify and implement communication protocols. + + +== Career == +From 1985 to 1992 he was an assistant professor in the UC Berkeley Computer Science Department, where he received the NSF Presidential Young Investigator and IBM Faculty Development awards. During this period he conducted several research projects: + +FORMULA (Forth Music Language), a parallel programming language and runtime system for computer music based on Forth. +MOOD (Musical Object-Oriented Dialect), a parallel programming language and runtime system for computer music based on C++. A port for MS-DOS also exists. +DASH, a distributed operating system with support for digital audio and video. +Continuous Media File System (CMFS), a file system for digital audio and video +Comet, an I/O server for digital audio and video. +From 1992 to 1994 he worked at Sonic Solutions, where he developed Sonic System, the first distributed system for professional digital audio editing. +From 1995 to 1998 he was chief technical officer of Tunes.com, where he developed web-based systems for music discovery based on collaborative filtering, acoustics, and other models. +In 1995 he joined David Gedye and Dan Werthimer in creating SETI@home, an early volunteer computing project. Anderson continues to direct SETI@home. +From 2000 to 2002, he served as CTO of United Devices, a company that developed software for distributed computing. +In 2002 he created the Berkeley Open Infrastructure for Network Computing (BOINC) project, which develops an open-source software platform for volunteer computing. The project is funded by NSF and is based at the UC Berkeley Space Sciences Laboratory. BOINC has been used by about 100 projects, including SETI@home, Einstein@home, Rosetta@home, Climateprediction.net, and the IBM World Community Grid, in areas as diverse as mathematics, medicine, molecular biology, climatology, and astrophysics. +Anderson was involved in Stardust@home, which used 23,000 volunteers to identify interstellar dust particles via the Web – an approach called distributed thinking. In 2007 Anderson developed BOSSA a software framework for distributed thinking, using volunteers on the Internet to perform tasks that require human intelligence, knowledge, or cognitive skills. +He also developed BOLT, a framework for web-based training and education in the context of volunteer computing and distributed thinking. + + +=== Music === +Since 2020 Anderson has been involved in software projects related to classical music: + +Music Match is a social site where performers and composers can meet and communicate with each other. +Classical Music Index is an offshoot of IMSLP in which users can rate and review compositions, and can discover compositions likely to appeal to their taste. +Numula is a Python library for computer rendition of music with complex variations in dynamics, timing, articulation and pedaling, as are typical in human performance. + + +=== Inventions === +In 1994 Anderson invented "Virtual Reality Television", a television system allowing viewers to control their virtual position and orientation. He was awarded a patent for this invention in 1996. +In 1994 he developed one of the first systems for collaborative filtering, and developed a web site, rare.com, that provided movie recommendations based on the user's movie ratings. + + +== References == + + +== External links == + +Profile of David Anderson \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Doug_Shane-0.md b/data/en.wikipedia.org/wiki/Doug_Shane-0.md new file mode 100644 index 000000000..f703e3469 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Doug_Shane-0.md @@ -0,0 +1,47 @@ +--- +title: "Doug Shane" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Doug_Shane" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:23.902016+00:00" +instance: "kb-cron" +--- + +Douglas Bennett Shane is President of The Spaceship Company, as well as an American test pilot who has trained as a commercial astronaut. He was a member of the Scaled Composites astronaut team and one of the test pilots for SpaceShipOne, the experimental spaceplane developed by Scaled Composites. +Shane worked as the operations director on the SpaceShipOne project in addition to being one of the program pilots, +and later served as President of Scaled Composites from 2008 through early 2013. + + +== Biography == +In 1982, Shane received a Bachelor of Science degree in aerospace engineering from the University of Kansas. +Shane built a Long-Ez he called the "Shane Runabout". + + +=== Scaled Composites === +In 1982, Shane joined Scaled Composites, in Mojave, California, as a test pilot and founding member. After 1989, he was responsible for business development, contracts, and proposals, as well as the company's flight test operations. +In 1997, Shane received the Iven C. Kincheloe Award from the Society of Experimental Test Pilots for his flight test work on the Williams V-Jet II and Vision Aire Vantage. He is a past President of the Society of Experimental Test Pilots. +In 2004, as director of flight operations, Shane supervised the Ansari X Prize qualification flights from the control room. Although he was one of the four qualified pilots for SpaceShipOne, Shane did not fly any of the flights himself. +In June 2008, Shane was appointed president of Scaled Composites, taking over this role from previous president and company founder Burt Rutan. He stayed in this position for five years, from 2008 through early 2013. + + +=== The Spaceship Company === +In June 2013, Shane joined The Spaceship Company (TSC) to become executive VP and general manager, ending a 31-year career with Scaled Composites, including five as president. +He was promoted to president of TSC in July 2014. + + +== See also == +Scaled Composites +SpaceShipOne +The Spaceship Company + + +== References == + + +== External links == +Scaled Composites biography +Biography on Encyclopedia Astronautica +List of American Astronauts +Auction entry for Shane signature under category "Astronaut Autographs" +Name \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Drake_equation-0.md b/data/en.wikipedia.org/wiki/Drake_equation-0.md new file mode 100644 index 000000000..6098dd180 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Drake_equation-0.md @@ -0,0 +1,105 @@ +--- +title: "Drake equation" +chunk: 1/8 +source: "https://en.wikipedia.org/wiki/Drake_equation" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:04.682878+00:00" +instance: "kb-cron" +--- + +The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way Galaxy. +The equation was formulated in 1961 by Frank Drake, not for purposes of quantifying the number of civilizations, but as a way to stimulate scientific dialogue at the first scientific meeting on the search for extraterrestrial intelligence (SETI). The equation summarizes the main concepts which scientists must contemplate when considering the question of other radio-communicative life. It is more properly thought of as an approximation than as a serious attempt to determine a precise number. +Criticism related to the Drake equation focuses not on the equation itself, but on the fact that the estimated values for several of its factors are highly conjectural, the combined multiplicative effect being that the uncertainty associated with any derived value is so large that the equation cannot be used to draw firm conclusions. + +== Equation == +The Drake equation is: + + + + + N + = + + R + + ∗ + + + ⋅ + + f + + + p + + + + ⋅ + + n + + + e + + + + ⋅ + + f + + + l + + + + ⋅ + + f + + + i + + + + ⋅ + + f + + + c + + + + ⋅ + L + + + {\displaystyle N=R_{*}\cdot f_{\mathrm {p} }\cdot n_{\mathrm {e} }\cdot f_{\mathrm {l} }\cdot f_{\mathrm {i} }\cdot f_{\mathrm {c} }\cdot L} + + +where + +N = the number of civilizations in the Milky Way galaxy with which communication might be possible (i.e. which are on the current past light cone); +and + +R∗ = the average rate of star formation in our galaxy. +fp = the fraction of those stars that have planets. +ne = the average number of planets that can potentially support life per star that has planets. +fl = the fraction of planets that could support life that actually develop life at some point. +fi = the fraction of planets with life that go on to develop intelligent life (civilizations). +fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space. +L = the length of time for which such civilizations release detectable signals into space. +This form of the equation first appeared in Drake's 1965 paper. + +== History == + +In September 1959, physicists Giuseppe Cocconi and Philip Morrison published an article in the journal Nature with the provocative title "Searching for Interstellar Communications". Cocconi and Morrison argued that radio telescopes had become sensitive enough to pick up transmissions that might be broadcast into space by civilizations orbiting other stars. Such messages, they suggested, might be transmitted at a wavelength of 21 cm (1,420.4 MHz). This is the wavelength of radio emission by neutral hydrogen, the most common element in the universe, and they reasoned that other intelligences might see this as a logical landmark in the radio spectrum. +Two months later, Harvard University astronomy professor Harlow Shapley speculated on the number of inhabited planets in the universe, saying "The universe has 10 million, million, million suns (10 followed by 18 zeros) similar to our own. One in a million has planets around it. Only one in a million million has the right combination of chemicals, temperature, water, days and nights to support planetary life as we know it. This calculation arrives at the estimated figure of 100 million worlds where life has been forged by evolution." +Seven months after Cocconi and Morrison published their article, Drake began searching for extraterrestrial intelligence in an experiment called Project Ozma. It was the first systematic search for signals from communicative extraterrestrial civilizations. Using the 85 ft (26 m) dish of the National Radio Astronomy Observatory, Green Bank in Green Bank, West Virginia, Drake monitored two nearby Sun-like stars: Epsilon Eridani and Tau Ceti, slowly scanning frequencies close to the 21 cm wavelength for six hours per day from April to July 1960. The project was well designed, inexpensive, and simple by today's standards. It detected no signals. +Soon thereafter, Drake hosted the first search for extraterrestrial intelligence conference on detecting their radio signals. The meeting was held at the Green Bank facility in 1961. The equation that bears Drake's name arose out of his preparations for the meeting. + +As I planned the meeting, I realized a few day[s] ahead of time we needed an agenda. And so I wrote down all the things you needed to know to predict how hard it's going to be to detect extraterrestrial life. And looking at them it became pretty evident that if you multiplied all these together, you got a number, N, which is the number of detectable civilizations in our galaxy. This was aimed at the radio search, and not to search for primordial or primitive life forms. +The ten attendees were conference organizer J. Peter Pearman, Frank Drake, Philip Morrison, businessman and radio amateur Dana Atchley, chemist Melvin Calvin, astronomer Su-Shu Huang, neuroscientist John C. Lilly, inventor Barney Oliver, astronomer Carl Sagan, and radio-astronomer Otto Struve. These participants called themselves "The Order of the Dolphin" (because of Lilly's work on dolphin communication), and commemorated their first meeting with a plaque at the observatory hall. + +== Usefulness == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Drake_equation-1.md b/data/en.wikipedia.org/wiki/Drake_equation-1.md new file mode 100644 index 000000000..365c322b6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Drake_equation-1.md @@ -0,0 +1,35 @@ +--- +title: "Drake equation" +chunk: 2/8 +source: "https://en.wikipedia.org/wiki/Drake_equation" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:04.682878+00:00" +instance: "kb-cron" +--- + +The Drake equation results in a summary of the factors affecting the likelihood that we might detect radio-communication from intelligent extraterrestrial life. The last three parameters, fi, fc, and L, are not known and are very difficult to estimate, with values ranging over many orders of magnitude (see § Criticism). Therefore, the usefulness of the Drake equation is not in the solving, but rather in the contemplation of all the various concepts which scientists must incorporate when considering the question of life elsewhere, and gives the question of life elsewhere a basis for scientific analysis. The equation has helped draw attention to some particular scientific problems related to life in the universe, for example abiogenesis, the development of multi-cellular life, and the development of intelligence itself. +Within the limits of existing human technology, any practical search for distant intelligent life must necessarily be a search for some manifestation of a distant technology. After about 50 years, the Drake equation is still of seminal importance because it is a 'road map' of what we need to learn in order to solve this fundamental existential question. It also formed the backbone of astrobiology as a science; although speculation is entertained to give context, astrobiology concerns itself primarily with hypotheses that fit firmly into existing scientific theories. Some 50 years of SETI have failed to find anything, even though radio telescopes, receiver techniques, and computational abilities have improved significantly since the early 1960s. SETI efforts since 1961 have conclusively ruled out widespread alien emissions near the 21 cm wavelength of the hydrogen frequency. + +== Estimates == + +=== Original estimates === +There is considerable disagreement on the values of these parameters, but the 'educated guesses' used by Drake and his colleagues in 1961 were: + +R∗ = 1 yr−1 (1 star formed per year, on the average over the life of the galaxy; this was regarded as conservative) +fp = 0.2 to 0.5 (one fifth to one half of all stars formed will have planets) +ne = 1 to 5 (stars with planets will have between 1 and 5 planets capable of developing life) +fl = 1 (100% of these planets will develop life) +fi = 1 (100% of which will develop intelligent life) +fc = 0.1 to 0.2 (10–20% of which will be able to communicate) +L = somewhere between 1000 and 100,000,000 years +Inserting the above minimum numbers into the equation gives a minimum N of 20 (see: Range of results). Inserting the maximum numbers gives a maximum of 50,000,000. Drake states that given the uncertainties, the original meeting concluded that N ≈ L, and there were probably between 1000 and 100,000,000 planets with civilizations in the Milky Way Galaxy. + +=== Current estimates === +This section discusses and attempts to list the best current estimates for the parameters of the Drake equation. + +==== Rate of star creation in this Galaxy, R∗ ==== +Calculations in 2010, from NASA and the European Space Agency indicate that the rate of star formation in this Galaxy is about 0.68–1.45 solar masses (M☉; 1.35×1030–2.88×1030 kg) of material per year. To get the number of stars per year, we divide this by the initial mass function (IMF) for stars, where the average new star's mass is about 0.5 M☉. This gives a star formation rate of about 1–3 stars per year. + +==== Fraction of those stars that have planets, fp ==== +Analysis of microlensing surveys, in 2012, has found that fp may approach 1—that is, stars are orbited by planets as a rule, rather than the exception; and that there are one or more bound planets per Milky Way star. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Drake_equation-2.md b/data/en.wikipedia.org/wiki/Drake_equation-2.md new file mode 100644 index 000000000..bda8b3916 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Drake_equation-2.md @@ -0,0 +1,21 @@ +--- +title: "Drake equation" +chunk: 3/8 +source: "https://en.wikipedia.org/wiki/Drake_equation" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:04.682878+00:00" +instance: "kb-cron" +--- + +==== Average number of planets that might support life per star that has planets, ne ==== +In November 2013, astronomers reported, based on Kepler space telescope data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of sun-like stars and red dwarf stars within the Milky Way Galaxy. 11 billion of these estimated planets may be orbiting sun-like stars. Since there are about 100 billion stars in the galaxy, this implies fp · ne is roughly 0.4. The nearest planet in the habitable zone is Proxima Centauri b, which is as close as about 4.2 light-years away. +The consensus at the Green Bank meeting was that ne had a minimum value between 3 and 5. Dutch science journalist Govert Schilling has opined that this is optimistic. Even if planets are in the habitable zone, the number of planets with the right proportion of elements is difficult to estimate. Brad Gibson, Yeshe Fenner, and Charley Lineweaver determined that about 10% of star systems in the Milky Way Galaxy are hospitable to life, by having heavy elements, being far from supernovae and being stable for a sufficient time. +The discovery of numerous gas giants in close orbit with their stars has introduced doubt that life-supporting planets commonly survive the formation of their stellar systems. So-called hot Jupiters may migrate from distant orbits to near orbits, in the process disrupting the orbits of habitable planets. +On the other hand, the variety of star systems that might have habitable zones is not just limited to solar-type stars and Earth-sized planets. It is now estimated that even tidally locked planets close to red dwarf stars might have habitable zones, although the flaring behavior of these stars might speak against this. The possibility of life on moons of gas giants (such as Jupiter's moon Europa, or Saturn's moons Titan and Enceladus) adds further uncertainty to this figure. +The authors of the rare Earth hypothesis propose a number of additional constraints on habitability for planets, including being in galactic zones with suitably low radiation, high star metallicity, and low enough density to avoid excessive asteroid bombardment. They also propose that it is necessary to have a planetary system with large gas giants which provide bombardment protection without a hot Jupiter; and a planet with plate tectonics, a large moon that creates tidal pools, and moderate axial tilt to generate seasonal variation. + +==== Fraction of the above that actually go on to develop life, fl ==== +Geological evidence from the Earth suggests that fl may be high; life on Earth appears to have begun around the same time as favorable conditions arose, suggesting that abiogenesis may be relatively common once conditions are right. However, this evidence only looks at the Earth (a single model planet), and contains anthropic bias, as the planet of study was not chosen randomly, but by the living organisms that already inhabit it (ourselves). From a classical hypothesis testing standpoint, without assuming that the underlying distribution of fl is the same for all planets in the Milky Way, there are zero degrees of freedom, permitting no valid estimates to be made. If life (or evidence of past life) were to be found on Mars, Europa, Enceladus or Titan that developed independently from life on Earth it would imply a value for fl close to 1. While this would raise the number of degrees of freedom from zero to one, there would remain a great deal of uncertainty on any estimate due to the small sample size, and the chance they are not really independent. +Countering this argument is that there is no evidence for abiogenesis occurring more than once on the Earth—that is, all terrestrial life stems from a common origin. If abiogenesis were more common it would be speculated to have occurred more than once on the Earth. Scientists have searched for this by looking for bacteria that are unrelated to other life on Earth, but none have been found yet. It is also possible that life arose more than once, but that other branches were out-competed, or died in mass extinctions, or were lost in other ways. Biochemists Francis Crick and Leslie Orgel laid special emphasis on this uncertainty: "At the moment we have no means at all of knowing" whether we are "likely to be alone in the galaxy (Universe)" or whether "the galaxy may be pullulating with life of many different forms." As an alternative to abiogenesis on Earth, they proposed the hypothesis of directed panspermia, which states that Earth life began with "microorganisms sent here deliberately by a technological society on another planet, by means of a special long-range unmanned spaceship". +In 2020, a paper by scholars at the University of Nottingham proposed an "Astrobiological Copernican" principle, based on the Principle of Mediocrity, and speculated that "intelligent life would form on other [Earth-like] planets like it has on Earth, so within a few billion years life would automatically form as a natural part of evolution". In the authors' framework, fl, fi, and fc are all set to a probability of 1 (certainty). Their resultant calculation concludes there are more than thirty current technological civilizations in the galaxy (disregarding error bars). \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Drake_equation-3.md b/data/en.wikipedia.org/wiki/Drake_equation-3.md new file mode 100644 index 000000000..587687785 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Drake_equation-3.md @@ -0,0 +1,45 @@ +--- +title: "Drake equation" +chunk: 4/8 +source: "https://en.wikipedia.org/wiki/Drake_equation" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:04.682878+00:00" +instance: "kb-cron" +--- + +==== Fraction of the above that develops intelligent life, fi ==== +This value remains particularly controversial. Those who favor a low value, such as the biologist Ernst Mayr, point out that of the billions of species that have existed on Earth, only one has become intelligent and from this, infer a tiny value for fi. Likewise, the Rare Earth hypothesis, notwithstanding their low value for ne above, also think a low value for fi dominates the analysis. Those who favor higher values note the generally increasing complexity of life over time, concluding that the appearance of intelligence is almost inevitable, implying an fi approaching 1. Skeptics point out that the large spread of values in this factor and others make all estimates unreliable. (See Criticism). +In addition, while it appears that life developed soon after the formation of Earth, the transition from single-celled prokaryotes to eukaryotes, and the resulting increase in complexity, including a change in life's "operating system", required a considerable amount of time as the complexity of living organisms grew. Subsequently, the Cambrian explosion, in which a large variety of multicellular life forms came into being, occurred a considerable amount of time after this event, which suggests the possibility that special conditions for complex life were necessary. Some scenarios such as the snowball Earth or research into extinction events have raised the possibility that life on Earth is relatively fragile. Research on any past life on Mars is relevant since a discovery that life did form on Mars but ceased to exist might raise the estimate of fl but would indicate that in half the known cases, intelligent life did not develop. +Estimates of fi have been affected by discoveries that the Solar System's orbit is circular in the galaxy, at such a distance that it remains out of the spiral arms for tens of millions of years (evading radiation from novae). Also, Earth's large moon may aid the evolution of life by stabilizing the planet's axis of rotation. +There has been quantitative work to begin to define + + + + + f + + + l + + + + ⋅ + + f + + + i + + + + + + {\displaystyle f_{\mathrm {l} }\cdot f_{\mathrm {i} }} + +. One example is a Bayesian analysis published in 2020. In the conclusion, the author cautions that this study applies to Earth's conditions. In Bayesian terms, the study favors the formation of intelligence on a planet with identical conditions to Earth but does not do so with high confidence. +Planetary scientist Pascal Lee of the SETI Institute proposes that this fraction is very low (0.0002). He based this estimate on how long it took Earth to develop intelligent life (1 million years since Homo erectus evolved, compared to 4.6 billion years since Earth formed). + +==== Fraction of the above revealing their existence via signal release into space, fc ==== +For deliberate communication, the one example we have (the Earth) does not do much explicit communication, though there are some efforts covering only a tiny fraction of the stars that might look for human presence. (See Arecibo message, for example). There is considerable speculation why an extraterrestrial civilization might exist but choose not to communicate. However, deliberate communication is not required, and calculations indicate that current or near-future Earth-level technology might well be detectable to civilizations not too much more advanced than present day humans. By this standard, the Earth is a communicating civilization. +Another question is what percentage of civilizations in the galaxy are close enough for us to detect, assuming that they send out signals. For example, existing Earth radio telescopes could only detect Earth radio transmissions from roughly a light year away. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Drake_equation-4.md b/data/en.wikipedia.org/wiki/Drake_equation-4.md new file mode 100644 index 000000000..65057a09d --- /dev/null +++ b/data/en.wikipedia.org/wiki/Drake_equation-4.md @@ -0,0 +1,33 @@ +--- +title: "Drake equation" +chunk: 5/8 +source: "https://en.wikipedia.org/wiki/Drake_equation" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:04.682878+00:00" +instance: "kb-cron" +--- + +==== Lifetime of such a civilization wherein it communicates its signals into space, L ==== +Michael Shermer estimated L as 420 years, based on the duration of sixty historical Earthly civilizations. Using 28 civilizations more recent than the Roman Empire, he calculates a figure of 304 years for "modern" civilizations. It could also be argued from Michael Shermer's results that the fall of most of these civilizations was followed by later civilizations that carried on the technologies, so it is doubtful that they are separate civilizations in the context of the Drake equation. In the expanded version, including reappearance number, this lack of specificity in defining single civilizations does not matter for the result, since such a civilization turnover could be described as an increase in the reappearance number rather than increase in L, stating that a civilization reappears in the form of the succeeding cultures. Furthermore, since none could communicate over interstellar space, the method of comparing with historical civilizations could be regarded as invalid. +David Grinspoon has argued that once a civilization has developed enough, it might overcome all threats to its survival. It will then last for an indefinite period of time, making the value for L potentially billions of years. If this is the case, then he proposes that the Milky Way Galaxy may have been steadily accumulating advanced civilizations since it formed. He proposes that the last factor L be replaced with fIC · T, where fIC is the fraction of communicating civilizations that become "immortal" (in the sense that they simply do not die out), and T representing the length of time during which this process has been going on. This has the advantage that T would be a relatively easy-to-discover number, as it would simply be some fraction of the age of the universe. +It has also been hypothesized that once a civilization has learned of a more advanced one, its longevity could increase because it can learn from the experiences of the other. +The astronomer Carl Sagan speculated that all of the terms, except for the lifetime of a civilization, are relatively high and the determining factor in whether there are large or small numbers of civilizations in the universe is the civilization lifetime, or in other words, the ability of technological civilizations to avoid self-destruction. In Sagan's case, the Drake equation was a strong motivating factor for his interest in environmental issues and his efforts to warn against the dangers of nuclear warfare. Paleobiologist Olev Vinn suggests that the lifetime of most technological civilizations is brief due to inherited behavior patterns present in all intelligent organisms. These behaviors, incompatible with civilized conditions, inevitably lead to self-destruction soon after the emergence of advanced technologies. +An intelligent civilization might not be organic, as some have suggested that artificial general intelligence may replace humanity. + +=== Range of results === +As many skeptics have pointed out, the Drake equation can give a very wide range of values, depending on the assumptions, as the values used in portions of the Drake equation are not well established. In particular, the result can be N ≪ 1, meaning we are likely alone in the galaxy, or N ≫ 1, implying there are many civilizations we might contact. One of the few points of wide agreement is that the presence of humanity demonstrates that the probability of intelligence arising is greater than zero. +As an example of a low estimate, combining NASA's star formation rates, the rare Earth hypothesis value of fp · ne · fl = 10−5, Mayr's view on intelligence arising, Drake's view of communication, and Shermer's estimate of lifetime: + +R∗ = 1.5–3 yr−1, fp · ne · fl = 10−5, fi = 10−9, fc = 0.2[Drake, above], and L = 304 years +gives: + +N = 1.5 × 10−5 × 10−9 × 0.2 × 304 = 9.1 × 10−13 (0.00000000000091 in non scientific notation) +i.e., suggesting that we are probably alone in this galaxy, and possibly in the observable universe. +On the other hand, with larger values for each of the parameters above, values of N can be derived that are greater than 1. The following higher values that have been proposed for each of the parameters: + +R∗ = 1.5–3 yr−1, fp = 1, ne = 0.2, fl = 0.13, fi = 1, fc = 0.2[Drake, above], and L = 109 years +Use of these parameters gives: + +N = 3 × 1 × 0.2 × 0.13 × 1 × 0.2 × 109 = 15,600,000 civilizations in the Milky Way with which communication might be possible +Monte Carlo simulations of estimates of the Drake equation factors based on a stellar and planetary model of the Milky Way have resulted in the number of civilizations varying by a factor of 100. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Drake_equation-5.md b/data/en.wikipedia.org/wiki/Drake_equation-5.md new file mode 100644 index 000000000..4770c76ab --- /dev/null +++ b/data/en.wikipedia.org/wiki/Drake_equation-5.md @@ -0,0 +1,172 @@ +--- +title: "Drake equation" +chunk: 6/8 +source: "https://en.wikipedia.org/wiki/Drake_equation" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:04.682878+00:00" +instance: "kb-cron" +--- + +=== Possible former technological civilizations === +In 2016, Adam Frank and Woodruff Sullivan modified the Drake equation to determine just how unlikely the event of a technological species arising on a given habitable planet must be, to give the result that Earth hosts the only technological species that has ever arisen, for two cases: (a) this Galaxy, and (b) the universe as a whole. By asking this different question, one removes the lifetime and simultaneous communication uncertainties. Since the numbers of habitable planets per star can today be reasonably estimated, the only remaining unknown in the Drake equation is the probability that a habitable planet ever develops a technological species over its lifetime. For Earth to have the only technological species that has ever occurred in the universe, they calculate the probability of any given habitable planet ever developing a technological species must be less than 2.5×10−24. Similarly, for Earth to have been the only case of hosting a technological species over the history of this Galaxy, the odds of a habitable zone planet ever hosting a technological species must be less than 1.7×10−11 (about 1 in 60 billion). The figure for the universe implies that it is extremely unlikely that Earth hosts the only technological species that has ever occurred. On the other hand, for this Galaxy one must think that fewer than 1 in 60 billion habitable planets develop a technological species for there not to have been at least a second case of such a species over the past history of this Galaxy. + +== Modifications == +As many observers have pointed out, the Drake equation is a very simple model that omits potentially relevant parameters, and many changes and modifications to the equation have been proposed. One line of modification, for example, attempts to account for the uncertainty inherent in many of the terms. +Combining the estimates of the original six factors by major researchers via a Monte Carlo procedure leads to a best value for the non-longevity factors of 0.85 1/years. This result differs insignificantly from the estimate of unity given both by Drake and the Cyclops report. +Others note that the Drake equation ignores many concepts that might be relevant to the odds of contacting other civilizations. For example, Glen David Brin states: "The Drake equation merely speaks of the number of sites at which ETIs spontaneously arise. The equation says nothing directly about the contact cross-section between an ETIS and contemporary human society". Because it is the contact cross-section that is of interest to the SETI community, many additional factors and modifications of the Drake equation have been proposed. + +Colonization +Brin proposed to generalize the Drake equation to include additional effects of alien civilizations colonizing other star systems. Each original site expands with an expansion velocity v, and establishes additional sites that survive for a lifetime L. The result is a more complex set of 3 equations. +Reappearance factor +The Drake equation may furthermore be multiplied by how many times an intelligent civilization may occur on planets where it has happened once. Even if an intelligent civilization reaches the end of its lifetime, life may still prevail on the planet for billions of years, permitting the next civilization to evolve. Thus, several civilizations may come and go during the lifespan of one and the same planet. Thus, if nr is the average number of times a new civilization reappears on the same planet where a previous civilization once has appeared and ended, then the total number of civilizations on such a planet would be 1 + nr, which is the actual reappearance factor added to the equation. +METI factor +Alexander Zaitsev said that to be in a communicative phase and emit dedicated messages are not the same. For example, humans are in a communicative phase, but are not a communicative civilization; there are no purposeful and regular transmission of interstellar messages. For this reason, he suggested introducing the METI factor (messaging to extraterrestrial intelligence) to the classical Drake equation. He defined the factor as "fm = The fraction of communicative civilizations with clear and non-paranoid planetary consciousness (that is, those which actually engage in deliberate interstellar transmission)". +Biogenic gases +Astronomer Sara Seager proposed a revised equation that focuses on the search for planets with biosignature gases. These gases are produced by living organisms that can accumulate in a planet atmosphere to levels that can be detected with remote space telescopes. +The Seager equation looks like: + + + + + N + = + + N + + ∗ + + + ⋅ + + F + + + Q + + + + ⋅ + + F + + + H + Z + + + + ⋅ + + F + + + O + + + + ⋅ + + F + + + L + + + + ⋅ + + F + + + S + + + + + + {\displaystyle N=N_{*}\cdot F_{\mathrm {Q} }\cdot F_{\mathrm {HZ} }\cdot F_{\mathrm {O} }\cdot F_{\mathrm {L} }\cdot F_{\mathrm {S} }} + + +where: +N = the number of planets with detectable signs of life +N∗ = the number of stars observed +FQ = the fraction of stars that are quiet +FHZ = the fraction of stars with rocky planets in the habitable zone +FO = the fraction of those planets that can be observed +FL = the fraction that have life +FS = the fraction on which life produces a detectable signature gas +Carl Sagan's version of the Drake equation +American astronomer Carl Sagan made some modifications in the Drake equation and presented it in the 1980 program Cosmos: A Personal Voyage. The modified equation is: + + + + + N + = + + N + + + ∗ + + + + ⋅ + + f + + + p + + + + ⋅ + + n + + + e + + + + ⋅ + + f + + + l + + + + ⋅ + + f + + + i + + + + ⋅ + + f + + + c + + + + ⋅ + + f + + + L + + + + + + {\displaystyle N=N_{\mathrm {*} }\cdot f_{\mathrm {p} }\cdot n_{\mathrm {e} }\cdot f_{\mathrm {l} }\cdot f_{\mathrm {i} }\cdot f_{\mathrm {c} }\cdot f_{\mathrm {L} }} + \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Drake_equation-6.md b/data/en.wikipedia.org/wiki/Drake_equation-6.md new file mode 100644 index 000000000..e51000479 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Drake_equation-6.md @@ -0,0 +1,43 @@ +--- +title: "Drake equation" +chunk: 7/8 +source: "https://en.wikipedia.org/wiki/Drake_equation" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:04.682878+00:00" +instance: "kb-cron" +--- + +where: +N = the number of civilizations in the Milky Way galaxy with which communication might be possible (i.e. which are on the current past light cone); +N∗ = Number of stars in the Milky Way Galaxy +fp = the fraction of those stars that have planets. +ne = the average number of planets that can potentially support life per star that has planets. +fl = the fraction of planets that could support life that actually develop life at some point. +fi = the fraction of planets with life that go on to develop intelligent life (civilizations). +fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space. +fL = fraction of a planetary lifetime graced by a technological civilization +Plate tectonics factor +Robert J. Stern and Taras V. Gerya proposed to add plate tectonics factors in the 2024 paper: + +We resolve the Fermi Paradox (1) by adding two additional terms to the Drake Equation: foc (the fraction of habitable exoplanets with significant continents and oceans) and fpt (the fraction of habitable exoplanets with significant continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by demonstrating that the product of foc and fpt is very small (< 0.00003–0.002). We propose that the lack of evidence for ACCs [active, communicative civilizations] reflects the scarcity of long-lived plate tectonics and/or continents and oceans on exoplanets with primitive life. + +== Criticism == +Criticism of the Drake equation is varied. Firstly, many of the terms in the equation are largely or entirely based on conjecture. Star formation rates are well-known, and the incidence of planets has a sound theoretical and observational basis, but the other terms in the equation become very speculative. The uncertainties revolve around the present day understanding of the evolution of life, intelligence, and civilization, not physics. No statistical estimates are possible for some of the parameters, where only one example is known. The net result is that the equation cannot be used to draw firm conclusions of any kind, and the resulting margin of error is huge, far beyond what some consider acceptable or meaningful. +Others point out that the equation was formulated before our understanding of the universe had matured. Astrophysicist Ethan Siegel, said: + +The Drake equation, when it was put forth, made an assumption about the Universe that we now know is untrue: It assumed that the Universe was eternal and static in time. As we learned only a few years after Frank Drake first proposed his equation, the Universe doesn’t exist in a steady state, where it’s unchanging in time, but rather has evolved from a hot, dense, energetic, and rapidly expanding state: a hot Big Bang that occurred over a finite duration in our cosmic past. +One reply to such criticisms is that even though the Drake equation currently involves speculation about unmeasured parameters, it was intended as a way to stimulate dialogue on these topics. Then the focus becomes how to proceed experimentally. Indeed, Drake originally formulated the equation merely as an agenda for discussion at the Green Bank conference. + +=== Fermi paradox === + +A civilization lasting for tens of millions of years could be able to spread throughout the galaxy, even at the slow speeds foreseeable with present-day technology. However, no confirmed signs of civilizations or intelligent life elsewhere have been found, either in this Galaxy or in the observable universe of 2 trillion galaxies. According to this line of thinking, the tendency to fill (or at least explore) all available territory seems to be a universal trait of living things, so the Earth should have already been colonized, or at least visited, but no evidence of this exists. Hence Fermi's question "Where is everybody?". +A large number of explanations have been proposed to explain this lack of contact; a book published in 2015 elaborated on 75 different explanations. In terms of the Drake Equation, the explanations can be divided into three classes: + +Few intelligent civilizations ever arise. This is an argument that at least one of the first few terms, R∗ · fp · ne · fl · fi, has a low value. The most common suspect is fi, but explanations such as the rare Earth hypothesis argue that ne is the small term. +Intelligent civilizations exist, but we see no evidence, meaning fc is small. Typical arguments include that civilizations are too far apart, it is too expensive to spread throughout the galaxy, civilizations broadcast signals for only a brief period of time, communication is dangerous, and many others. +The lifetime of intelligent, communicative civilizations is short, meaning the value of L is small. Drake suggested that a large number of extraterrestrial civilizations would form, and he further speculated that the lack of evidence of such civilizations may be because technological civilizations tend to disappear rather quickly. Typical explanations include it is the nature of intelligent life to destroy itself, it is the nature of intelligent life to destroy others, they tend to be destroyed by natural events, and others. +These lines of reasoning lead to the Great Filter hypothesis, which states that since there are no observed extraterrestrial civilizations despite the vast number of stars, at least one step in the process must be acting as a filter to reduce the final value. According to this view, either it is very difficult for intelligent life to arise, or the lifetime of technologically advanced civilizations, or the period of time they reveal their existence must be relatively short. +An analysis by Anders Sandberg, Eric Drexler and Toby Ord suggests "a substantial ex ante (predicted) probability of there being no other intelligent life in our observable universe". + +== In popular culture == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Drake_equation-7.md b/data/en.wikipedia.org/wiki/Drake_equation-7.md new file mode 100644 index 000000000..3935ae69c --- /dev/null +++ b/data/en.wikipedia.org/wiki/Drake_equation-7.md @@ -0,0 +1,87 @@ +--- +title: "Drake equation" +chunk: 8/8 +source: "https://en.wikipedia.org/wiki/Drake_equation" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:04.682878+00:00" +instance: "kb-cron" +--- + +The equation was cited by Gene Roddenberry as supporting the multiplicity of inhabited planets shown on Star Trek, the television series he created. However, Roddenberry did not have the equation with him, and he was forced to "invent" it for his original proposal. The invented equation created by Roddenberry is: + + + + + F + + f + + 2 + + + ( + M + g + E + ) + − + + C + + 1 + + + R + + i + + 1 + + + ⋅ + M + = + L + + / + + S + o + + + {\displaystyle Ff^{2}(MgE)-C^{1}Ri^{1}\cdot M=L/So} + + +Regarding Roddenberry's fictional version of the equation, Drake himself commented that a number raised to the first power is just the number itself. +A commemorative plate on NASA's Europa Clipper mission, which launched October 14, 2024, features a poem by the U.S. Poet Laureate Ada Limón, waveforms of the word 'water' in 103 languages, a schematic of the water hole, the Drake equation, and a portrait of planetary scientist Ron Greeley on it. + +== See also == +Astrobiology – Science concerned with life in the universe +Goldilocks principle – Analogy for optimal conditions +Kardashev scale – Measure of a civilization's evolution +Planetary habitability – Known extent to which a planet is suitable for life +Ufology – Study of UFOs +Lincoln index – Statistical measure +The Search for Life: The Drake Equation, BBC documentary + +== Notes == + +== References == + +== Further reading == +Morton, Oliver (2002). "A Mirror in the Sky". In Graham Formelo (ed.). It Must Be Beautiful. Granta Books. ISBN 1-86207-555-7. +Rood, Robert T.; James S. Trefil (1981). Are We Alone? The Possibility of Extraterrestrial Civilizations. New York: Scribner. ISBN 0684178427. +Vakoch, Douglas A.; Dowd, Matthew F., eds. (2015). The Drake Equation: Estimating the Prevalence of Extraterrestrial Life Through the Ages. Cambridge, UK: Cambridge University Press. ISBN 978-1-10-707365-4. + +== External links == + +Interactive Drake Equation Calculator +Frank Drake's 2010 article on "The Origin of the Drake Equation" +"Only a matter of time, says Frank Drake". A Q&A with Frank Drake in February 2010 +Drake, Frank (December 2004). "The E.T. Equation, Recalculated". Wired. +Macromedia Flash page allowing the user to modify Drake's values from PBS's Nova +"The Drake Equation", Astronomy Cast episode #23; includes full transcript +Animated simulation of the Drake equation. (Archived 8 December 2015 at the Wayback Machine) +"The Alien Equation", BBC Radio program Discovery (22 September 2010) +"Reflections on the Equation" (PDF), by Frank Drake, 2013 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Dyson_sphere-0.md b/data/en.wikipedia.org/wiki/Dyson_sphere-0.md index 7165dd73a..8a15771f4 100644 --- a/data/en.wikipedia.org/wiki/Dyson_sphere-0.md +++ b/data/en.wikipedia.org/wiki/Dyson_sphere-0.md @@ -4,7 +4,7 @@ chunk: 1/2 source: "https://en.wikipedia.org/wiki/Dyson_sphere" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T06:23:23.565520+00:00" +date_saved: "2026-05-05T13:16:07.227065+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Dyson_sphere-1.md b/data/en.wikipedia.org/wiki/Dyson_sphere-1.md index 9a06ba4b0..ee808cd9c 100644 --- a/data/en.wikipedia.org/wiki/Dyson_sphere-1.md +++ b/data/en.wikipedia.org/wiki/Dyson_sphere-1.md @@ -4,7 +4,7 @@ chunk: 2/2 source: "https://en.wikipedia.org/wiki/Dyson_sphere" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T06:23:23.565520+00:00" +date_saved: "2026-05-05T13:16:07.227065+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Dyson–Harrop_satellite-0.md b/data/en.wikipedia.org/wiki/Dyson–Harrop_satellite-0.md new file mode 100644 index 000000000..607792ccb --- /dev/null +++ b/data/en.wikipedia.org/wiki/Dyson–Harrop_satellite-0.md @@ -0,0 +1,16 @@ +--- +title: "Dyson–Harrop satellite" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Dyson–Harrop_satellite" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:08.410575+00:00" +instance: "kb-cron" +--- + +A Dyson–Harrop satellite is a hypothetical megastructure intended for power generation using the solar wind. It is inspired by the Dyson sphere, but much harder to detect from another star system. The satellite develops a useful voltage potential by capturing positive ions against a solar sail for a net positive voltage, while draining off electrons on a long wire, and guiding flux electrons along a short wire into a charge receiver for a net negative voltage. The voltage difference between the charge receiver and the solar sail is used to power a laser or microwave transmitter for power transfer off-board the satellite. +The concept for the so-called Dyson–Harrop satellite begins with a long metal wire loop pointed at the Sun. This wire is charged to generate a cylindrical magnetic field that snags the electrons that make up half the solar wind. These electrons get funneled into a metal spherical receiver to produce a current, which generates the wire's magnetic field – making the system self-sustaining. Any current not needed for the magnetic field powers an infrared laser trained on satellite dishes back on Earth, designed to collect the energy. Earth's air does not absorb infra-red light, so the system would be highly efficient. Back on the satellite, the current has been drained of its electrical energy by the laser – the electrons fall onto a ring-shaped sail, where incoming sunlight can excite them enough to keep the satellite in orbit around the Sun. +A relatively small Dyson–Harrop satellite using a 1-centimetre-wide copper wire 300 metres long, a receiver 2 metres wide and a sail 10 metres in diameter, sitting at roughly the same distance from the Sun as the Earth, could generate 1.7 megawatts of power – enough for about 1000 family homes in the US. Larger sizes could produce far greater amounts of power, even exceeding the current usage of Earth. Satellites could be placed anywhere in the Solar System, and networks of satellites could combine to generate terawatts of power. + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-0.md b/data/en.wikipedia.org/wiki/Exoplanet-0.md new file mode 100644 index 000000000..c1df010cd --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-0.md @@ -0,0 +1,31 @@ +--- +title: "Exoplanet" +chunk: 1/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detected in 1988, was confirmed in 2003. In 2016, it was recognized that the first possible evidence of an exoplanet had been noted in 1917. As of 23 April 2026, there are 6,273 confirmed exoplanets in 4,694 planetary systems, with 1,049 systems having more than one planet. +There are many methods of detecting exoplanets. Transit photometry and Doppler spectroscopy have found the most, but these methods suffer from a clear observational bias favoring the detection of large planets close to the star. About 1 in 5 Sun-like stars are estimated to have an "Earth-sized" planet in the habitable zone. Assuming there are 200 billion stars in the Milky Way, it can be hypothesized that there are 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if planets orbiting the numerous red dwarfs are included. +The least massive exoplanet known is Draugr, which is about twice the mass of the Moon. The most massive exoplanet listed on the NASA Exoplanet Archive is HR 2562 b, about 30 times the mass of Jupiter. However, according to some definitions of a planet (based on the nuclear fusion of deuterium), it is too massive to be a planet and might be a brown dwarf. Known orbital times for exoplanets vary from less than an hour (for those closest to their star) to thousands of years. Some exoplanets are so far away from the star that it is difficult to tell whether they are gravitationally bound to it. +The nearest exoplanets are located 4.2 light-years (1.3 parsecs) from Earth and orbit Proxima Centauri, the closest star to the Sun. At the other extreme, there is evidence for extragalactic planets – exoplanets located in other galaxies. +The discovery of exoplanets has intensified interest in the search for extraterrestrial life. There is special interest in planets that orbit in a star's habitable zone (sometimes called "goldilocks zone"), where it is possible for liquid water, a prerequisite for life as we know it, to exist on the surface. However, the study of planetary habitability also considers a wide range of other factors in determining the suitability of a planet for hosting life. +In collaboration with ground-based and other space-based observatories, the James Webb Space Telescope (JWST) is expected to give more insight into exoplanet traits, such as their composition, environmental conditions, and habitability. +Rogue planets are those that are not in planetary systems. Such objects are generally considered in a separate category from planets, especially if they are gas giants, often counted as sub-brown dwarfs. The number of rogue planets in the Milky Way is possibly in the billions. + +== Definition == + +=== IAU === +The official definition of the term planet used by the International Astronomical Union (IAU) only covers the Solar System and thus does not apply to exoplanets. The IAU Working Group on Extrasolar Planets issued a position statement containing a working definition of "planet" in 2001 and which was modified in 2003. An exoplanet was defined by the following criteria: + +Objects with true masses below the limiting mass for thermonuclear fusion of deuterium (currently calculated to be 13 Jupiter masses for objects of solar metallicity) that orbit stars or stellar remnants are "planets" (no matter how they formed). The minimum mass/size required for an extrasolar object to be considered a planet should be the same as that used in the Solar System. +Substellar objects with true masses above the limiting mass for thermonuclear fusion of deuterium are "brown dwarfs", no matter how they formed or where they are located. +Free-floating objects in young star clusters with masses below the limiting mass for thermonuclear fusion of deuterium are not "planets", but are "sub-brown dwarfs" (or whatever name is most appropriate). + +This working definition was amended by the IAU's Commission F2: Exoplanets and the Solar System in August 2018. The official working definition of an exoplanet is now as follows: + +Objects with true masses below the limiting mass for thermonuclear fusion of deuterium (currently calculated to be 13 Jupiter masses for objects of solar metallicity) that orbit stars, brown dwarfs or stellar remnants and that have a mass ratio with the central object below the L4/L5 instability (M/Mcentral < 2/(25+√621)) are "planets" (no matter how they formed). +The minimum mass/size required for an extrasolar object to be considered a planet should be the same as that used in our Solar System. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-1.md b/data/en.wikipedia.org/wiki/Exoplanet-1.md new file mode 100644 index 000000000..0d9450295 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-1.md @@ -0,0 +1,30 @@ +--- +title: "Exoplanet" +chunk: 2/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +=== Alternatives === +The IAU's working definition is not always used. One alternate suggestion is that planets should be distinguished from brown dwarfs on the basis of their formation. It is widely thought that giant planets form through core accretion, which may sometimes produce planets with masses above the deuterium fusion threshold; massive planets of that sort may have already been observed. Brown dwarfs form like stars from the direct gravitational collapse of clouds of gas, and this formation mechanism also produces objects that are below the 13 MJup limit and can be as low as 1 MJup. Objects in this mass range that orbit their stars with wide separations of hundreds or thousands of astronomical units (AU) and have large star/object mass ratios likely formed as brown dwarfs; their atmospheres would likely have a composition more similar to their host star than accretion-formed planets, which would contain increased abundances of heavier elements. Most directly imaged planets as of April 2014 are massive and have wide orbits so probably represent the low-mass end of a brown dwarf formation. One study suggests that objects above 10 MJup formed through gravitational instability and should not be thought of as planets. +Also, the 13-Jupiter-mass cutoff does not have a precise physical significance. Deuterium fusion can occur in some objects with a mass below that cutoff. The amount of deuterium fused depends to some extent on the composition of the object. In 2011, the Extrasolar Planets Encyclopaedia included objects up to 25 Jupiter masses, saying, "The fact that there is no special feature around 13 MJup in the observed mass spectrum reinforces the choice to forget this mass limit". As of 2016, this limit was increased to 60 Jupiter masses based on a study of mass–density relationships. The Exoplanet Data Explorer includes objects up to 24 Jupiter masses with the advisory: "The 13 Jupiter-mass distinction by the IAU Working Group is physically unmotivated for planets with rocky cores, and observationally problematic due to the sin i ambiguity." The NASA Exoplanet Archive includes objects with a mass (or minimum mass) equal to or less than 30 Jupiter masses. Another criterion for separating planets and brown dwarfs, rather than deuterium fusion, formation process or location, is whether the core pressure is dominated by Coulomb pressure or electron degeneracy pressure with the dividing line at around 5 Jupiter masses. + +=== Confirmation === +An exoplanet is confirmed for NASA's Exoplanet Archive either when "different observation techniques reveal features that can only be explained by a planet" or by analytical techniques. For the Extrasolar Planets Encyclopedia, "A planet is considered as Confirmed if it is claimed unambiguously in an accepted paper or a professional conference." + +== Nomenclature == + +The convention for naming exoplanets is an extension of the system used for designating multiple-star systems as adopted by the International Astronomical Union (IAU). For exoplanets orbiting a single star, the IAU designation is formed by taking the designated or proper name of its parent star, and adding a lower case letter. Letters are given in order of each planet's discovery around the parent star, so that the first planet discovered in a system is designated "b" (the parent star is considered "a") and later planets are given subsequent letters. If several planets in the same system are discovered at the same time, the closest one to the star gets the next letter, followed by the other planets in order of orbital size. A provisional IAU-sanctioned standard exists to accommodate the designation of circumbinary planets. A limited number of exoplanets have IAU-sanctioned proper names. Other naming systems exist. + +== History of detection == + +For centuries scientists, philosophers, and science fiction writers suspected that extrasolar planets existed, but there was no way of knowing whether they were real in fact, how common they were, or how similar they might be to the planets of the Solar System. Various detection claims made in the nineteenth century were rejected by astronomers. +The first evidence of a possible exoplanet, orbiting Van Maanen 2, was recorded in 1917, but was not recognized as such until 2016. The astronomer Walter Sydney Adams produced a spectrum of the star using Mount Wilson's 60-inch telescope which he interpreted the spectrum to be of an F-type main-sequence star. This spectrum was reexamined during studies of white dwarf stars with unpredicted compositions. It is now thought that such a spectrum could be caused by the residue of a nearby exoplanet that had been pulverized by the gravity of the star, the resulting dust then falling onto the star. +Numerous other claims of discovery took place in the mid 20th century, involving 61 Cygnus, Lalande 21185, and Barnard's Star, which were not discredited until the mid to late 1970s (see Discredited claims below). Another suspected scientific detection of an exoplanet occurred in 1988. Shortly afterwards, the first detection that is currently accepted came in 1992 when Aleksander Wolszczan and Dale Frail announced the discovery of two terrestrial-mass planets orbiting the millisecond pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. + +In February 2018, researchers using the Chandra X-ray Observatory, combined with a planet detection technique called microlensing, found evidence of planets in a distant galaxy, stating, "Some of these exoplanets are as (relatively) small as the moon, while others are as massive as Jupiter. Unlike Earth, most of the exoplanets are not tightly bound to stars, so they're actually wandering through space or loosely orbiting between stars. We can estimate that the number of planets in this [faraway] galaxy is more than a trillion." + +=== Early speculations === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-2.md b/data/en.wikipedia.org/wiki/Exoplanet-2.md new file mode 100644 index 000000000..709fd4bbc --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-2.md @@ -0,0 +1,23 @@ +--- +title: "Exoplanet" +chunk: 3/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +In the sixteenth century, the Italian philosopher Giordano Bruno, an early supporter of the Copernican theory that Earth and other planets orbit the Sun (heliocentrism), put forward the view that fixed stars are similar to the Sun and are likewise accompanied by planets. +In the eighteenth century, the same possibility was mentioned by Isaac Newton in the "General Scholium" that concludes his Principia. Making a comparison to the Sun's planets, he wrote "And if the fixed stars are the centres of similar systems, they will all be constructed according to a similar design and subject to the dominion of One." +In 1938, D.Belorizky demonstrated that it was realistic to search for exo-Jupiters by using transit photometry. +In 1952, more than 40 years before the first hot Jupiter was discovered, Otto Struve wrote that there is no compelling reason that planets could not be much closer to their parent star than is the case in the Solar System, and proposed that Doppler spectroscopy and the transit method could detect super-Jupiters in short orbits. + +=== Discredited claims === +Claims of exoplanet detections have been made since the nineteenth century. Some of the earliest involve the binary star 70 Ophiuchi. In 1855, William Stephen Jacob at the East India Company's Madras Observatory reported that orbital anomalies made it "highly probable" that there was a "planetary body" in this system. In the 1890s, Thomas J. J. See of the University of Chicago and the United States Naval Observatory stated that the orbital anomalies proved the existence of a dark body in the 70 Ophiuchi system with a 36-year period around one of the stars. However, Forest Ray Moulton published a paper proving that a three-body system with those orbital parameters would be highly unstable. +Multiple claims have been made that 61 Cygni might have a planetary system. Kaj Strand of the Sproul Observatory in 1942 observed tiny but systematic variations in the orbital motions of 61 Cygni A and B, suggesting that a third body of about 16 Jupiter masses must be orbiting 61 Cygni A. Multiple further claims were made, but more recent observations have yet to find confirmation. More information at 61 Cygni § Claims of a planetary system. +Around the same time that 61 Cygni was being investigated, similar claims about the presence of exoplanets were made about Lalande 21185: Lalande 21185 § Past claims of planets. +During the 1950s and 1960s, Peter van de Kamp of Swarthmore College made another prominent series of detection claims, this time for planets orbiting Barnard's Star. Astronomers now generally regard all early reports of detection as erroneous. +In 1991, Andrew Lyne, M. Bailes and S. L. Shemar claimed to have discovered a pulsar planet in orbit around PSR 1829-10, using pulsar timing variations. The claim briefly received intense attention, but Lyne and his team soon retracted it. + +=== Confirmed discoveries === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-3.md b/data/en.wikipedia.org/wiki/Exoplanet-3.md new file mode 100644 index 000000000..3125eeaf0 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-3.md @@ -0,0 +1,28 @@ +--- +title: "Exoplanet" +chunk: 4/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +As of 23 April 2026, a total of 6,273 confirmed exoplanets are listed in the NASA Exoplanet Archive, including a few that were confirmations of controversial claims from the late 1980s. The first published discovery to receive subsequent confirmation was made in 1988 by the Canadian astronomers Bruce Campbell, G. A. H. Walker, and Stephenson Yang of the University of Victoria and the University of British Columbia. Although they were cautious about claiming a planetary detection, their radial-velocity observations suggested that a planet orbits the star Gamma Cephei. Partly because the observations were at the very limits of instrumental capabilities at the time, astronomers remained skeptical for several years about this and other similar observations. It was thought some of the apparent planets might instead have been brown dwarfs, objects intermediate in mass between planets and stars. In 1990, additional observations were published that supported the existence of the planet orbiting Gamma Cephei, but subsequent work in 1992 again raised serious doubts. Finally, in 2003, improved techniques allowed the planet's existence to be confirmed. +On 9 January 1992, radio astronomers Aleksander Wolszczan and Dale Frail announced the discovery of two planets orbiting the millisecond pulsar PSR 1257+12 based on the variability of timing of the pulses. This discovery was confirmed, and is generally considered to be the first definitive detection of exoplanets. Follow-up observations solidified these results, and confirmation of a third planet in 1994 revived the topic in the popular press. These pulsar planets are thought to have formed from the unusual remnants of the supernova that produced the pulsar, in a second round of planet formation, or else to be the remaining rocky cores of gas giants that somehow survived the supernova and then decayed into their current orbits. As pulsars are aggressive stars, it was considered unlikely at the time that a planet could form in their orbit. +In the early 1990s, a group of astronomers led by Donald Backer, who were studying what they thought was a binary pulsar (PSR B1620−26 b), determined that a third object was needed to explain the observed Doppler shifts. Within a few years, the gravitational effects of the planet on the orbit of the pulsar and white dwarf had been measured, giving an estimate of the mass of the third object that was too small to be a star. The conclusion that the third object was a planet was announced by Stephen Thorsett and his collaborators in 1993. +On 6 October 1995, Michel Mayor and Didier Queloz of the University of Geneva announced the first definitive detection of an exoplanet orbiting a main-sequence star, nearby G-type star 51 Pegasi. This discovery, made at the Observatoire de Haute-Provence, ushered in the modern era of exoplanetary discovery, and was recognized by a share of the 2019 Nobel Prize in Physics. Technological advances, most notably in high-resolution spectroscopy, led to the rapid detection of many new exoplanets: astronomers could detect exoplanets indirectly by measuring their gravitational influence on the motion of their host stars. More extrasolar planets were later detected by observing the variation in a star's apparent luminosity as an orbiting planet transited in front of it. +Initially, most known exoplanets were massive planets that orbited very close to their parent stars. Astronomers were surprised by these "hot Jupiters", because theories of planetary formation had indicated that giant planets should only form at large distances from stars. But eventually more planets of other sorts were found, and it is now clear that hot Jupiters make up a minority of exoplanets. In 1999, Upsilon Andromedae became the first main-sequence star known to have multiple planets. Kepler-16 contains the first discovered planet that orbits a binary main-sequence star system. +On 26 February 2014, NASA announced the discovery of 715 newly verified exoplanets around 305 stars by the Kepler Space Telescope. These exoplanets were checked using a statistical technique called "verification by multiplicity". Before these results, most confirmed planets were gas giants comparable in size to Jupiter or larger because they were more easily detected, but the Kepler planets are mostly between the size of Neptune and the size of Earth. +On 23 July 2015, NASA announced Kepler-452b, a near-Earth-size planet orbiting the habitable zone of a G2-type star. +On 6 September 2018, NASA discovered an exoplanet about 145 light years away from Earth in the constellation Virgo. This exoplanet, Wolf 503b, is twice the size of Earth and was discovered orbiting a type of star known as an "Orange Dwarf". Wolf 503b completes one orbit in as few as six days because it is very close to the star. Wolf 503b is the only exoplanet that large that can be found near the so-called small planet radius gap. The gap, sometimes called the Fulton gap, is the observation that it is unusual to find exoplanets with sizes between 1.5 and 2 times the radius of the Earth. + +=== Candidate discoveries === +As of January 2020, NASA's Kepler and TESS missions had identified 4374 planetary candidates yet to be confirmed, several of them being nearly Earth-sized and located in the habitable zone, some around Sun-like stars. + + +In September 2020, astronomers reported evidence, for the first time, of an extragalactic planet, M51-ULS-1b, detected by eclipsing a bright X-ray source (XRS), in the Whirlpool Galaxy (M51a). + +== Detection methods == + +=== Direct imaging === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-4.md b/data/en.wikipedia.org/wiki/Exoplanet-4.md new file mode 100644 index 000000000..87af0e226 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-4.md @@ -0,0 +1,42 @@ +--- +title: "Exoplanet" +chunk: 5/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +Planets are extremely faint compared to their parent stars. For example, a Sun-like star is about a billion times brighter than the reflected light from any exoplanet orbiting it. It is difficult to detect such a faint light source, and furthermore, the parent star causes a glare that tends to wash it out. It is necessary to block the light from the parent star to reduce the glare while leaving the light from the planet detectable; doing so is a major technical challenge which requires extreme optothermal stability. Almost all exoplanets that have been directly imaged are both large (more massive than Jupiter) and widely separated from their parent stars. +Specially designed direct-imaging instruments such as Gemini Planet Imager, VLT-SPHERE, and SCExAO will image dozens of gas giants, but the vast majority of known extrasolar planets have only been detected through indirect methods. + +=== Indirect methods === +Transit method +If a planet crosses (or transits) in front of its parent star's disk, then the observed brightness of the star drops by a small amount. The amount by which the star dims depends on its size and on the size of the planet, among other factors. Because the transit method requires that the planet's orbit intersect a line-of-sight between the host star and Earth, the probability that an exoplanet in a randomly oriented orbit will be observed to transit the star is somewhat small. The Kepler telescope used this method. +Radial velocity or Doppler method +As a planet orbits a star, the star also moves in its own small orbit around the system's center of mass. Variations in the star's radial velocity—that is, the speed with which it moves towards or away from Earth—can be detected from displacements in the star's spectral lines due to the Doppler effect. Extremely small radial-velocity variations can be observed, of 1 m/s or even somewhat less. +Transit timing variation (TTV) +When multiple planets are present, each one slightly perturbs the others' orbits. Small variations in the times of transit for one planet can thus indicate the presence of another planet, which itself may or may not transit. For example, variations in the transits of the planet Kepler-19b suggest the existence of a second planet in the system, the non-transiting Kepler-19c. +Transit duration variation (TDV) + When a planet orbits multiple stars or if the planet has moons, its transit time can significantly vary per transit. Although no new planets or moons have been discovered with this method, it is used to successfully confirm many transiting circumbinary planets. +Gravitational microlensing +Microlensing occurs when the gravitational field of a star acts like a lens, magnifying the light of a distant background star. Planets orbiting the lensing star can cause detectable anomalies in magnification as it varies over time. Unlike most other methods which have a detection bias towards planets with small (or for resolved imaging, large) orbits, the microlensing method is most sensitive to detecting planets around 1–10 AU away from Sun-like stars. +Astrometry + Astrometry consists of precisely measuring a star's position in the sky and observing the changes in that position over time. The motion of a star due to the gravitational influence of a planet may be observable. Because the motion is so small, however, this method was not very productive until the 2020s. It has produced only a few confirmed discoveries, though it has been successfully used to investigate the properties of planets found in other ways. +Pulsar timing +A pulsar, a small, dense remnant of a star that has exploded as a supernova, emits radio waves regularly as it rotates. If planets orbit the pulsar, the motion of the pulsar around the system's center of mass alters the pulsar's distance to Earth over time. As a result, the radio pulses from the pulsar arrive on Earth at a later or earlier time. This light travel delay due to the pulsar being physically closer or farther from Earth is known as a Roemer time delay. The first confirmed discovery of an extrasolar planet was made using this method. But as of 2011, it has not been very productive; five planets have been detected in this way, around three different pulsars. +Variable star timing (pulsation frequency) +Like pulsars, there are some other types of stars which exhibit periodic activity. Deviations from periodicity can sometimes be caused by a planet orbiting it. As of 2013, a few planets have been discovered with this method. +Reflection/emission modulations +When a planet orbits very close to a star, it catches a considerable amount of starlight. As the planet orbits the star, the amount of light changes due to planets having phases from Earth's viewpoint or planets glowing more from one side than the other due to temperature differences. +Relativistic beaming +Relativistic beaming measures the observed flux from the star due to its motion. The brightness of the star changes as the planet moves closer or further away from its host star. +Ellipsoidal variations +Massive planets close to their host stars can slightly deform the shape of the star. This causes the brightness of the star to slightly deviate depending on how it is rotated relative to Earth. +Polarimetry +With the polarimetry method, a polarized light reflected off the planet is separated from unpolarized light emitted from the star. No new planets have been discovered with this method, although a few already discovered planets have been detected with this method. +Circumstellar disks +Disks of space dust surround many stars, thought to originate from collisions among asteroids and comets. The dust can be detected because it absorbs starlight and re-emits it as infrared radiation. Features on the disks may suggest the presence of planets, though this is not considered a definitive detection method. + +== Formation and evolution == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-5.md b/data/en.wikipedia.org/wiki/Exoplanet-5.md new file mode 100644 index 000000000..4b6ac1753 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-5.md @@ -0,0 +1,31 @@ +--- +title: "Exoplanet" +chunk: 6/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +Planets may form within a few to tens (or more) of millions of years of their star forming. +The planets of the Solar System can only be observed in their current state, but observations of different planetary systems of varying ages allows us to observe planets at different stages of evolution. Available observations range from young protoplanetary disks where planets are still forming to planetary systems of over 10 Gyr old. When planets form in a gaseous protoplanetary disk, they accrete hydrogen/helium envelopes. These envelopes cool and contract over time and, depending on the mass of the planet, some or all of the hydrogen/helium is eventually lost to space. This means that even terrestrial planets may start off with large radii if they form early enough. An example is Kepler-51b which has only about twice the mass of Earth but is almost the size of Saturn, which is a hundred times the mass of Earth. Kepler-51b is quite young at a few hundred million years old. + +== Planet-hosting stars == + +There is at least one planet on average per star. About 1 in 5 Sun-like stars have an "Earth-sized" planet in the habitable zone. +Most known exoplanets orbit stars roughly similar to the Sun, i.e. main-sequence stars of spectral categories F, G, or K. Lower-mass stars (red dwarfs, of spectral category M) are less likely to have planets massive enough to be detected by the radial-velocity method. Despite this, several tens of planets around red dwarfs have been discovered by the Kepler space telescope, which uses the transit method to detect smaller planets. +Using data from Kepler, a correlation has been found between the metallicity of a star and the probability that the star hosts a giant planet, similar to the size of Jupiter. Stars with higher metallicity are more likely to have planets, especially giant planets, than stars with lower metallicity. +Some planets orbit one member of a binary star system, and several circumbinary planets have been discovered which orbit both members of a binary star. A few planets in triple star systems are known and one in the quadruple system Kepler-64. + +== Orbital and physical parameters == + +== General features == + +=== Color and brightness === +The apparent brightness (apparent magnitude) of a planet depends on how far away the observer is, how reflective the planet is (albedo), and how much light the planet receives from its star, which depends on how far the planet is from the star and how bright the star is. So, a planet with a low albedo that is close to its star can appear brighter than a planet with a high albedo that is far from the star. +In 2013, the color of an exoplanet was determined for the first time. The best-fit albedo measurements of HD 189733b suggest that it is deep dark blue. Later that same year, the colors of several other exoplanets were determined, including GJ 504 b which visually has a magenta color, and Kappa Andromedae b, which if seen up close would appear reddish in color. Helium planets are expected to be white or grey in appearance. +The darkest known planet in terms of geometric albedo is TrES-2b, a hot Jupiter that reflects less than 1% of the light from its star, making it less reflective than coal or black acrylic paint. Hot Jupiters are expected to be quite dark due to sodium and potassium in their atmospheres, but it is not known why TrES-2b is so dark—it could be due to an unknown chemical compound. +For gas giants, geometric albedo generally decreases with increasing metallicity or atmospheric temperature unless there are clouds to modify this effect. Increased cloud-column depth increases the albedo at optical wavelengths, but decreases it at some infrared wavelengths. Optical albedo increases with age, because older planets have higher cloud-column depths. Optical albedo decreases with increasing mass, because higher-mass giant planets have higher surface gravities, which produces lower cloud-column depths. Also, elliptical orbits can cause major fluctuations in atmospheric composition, which can have a significant effect. +There is more thermal emission than reflection at some near-infrared wavelengths for massive and/or young gas giants. So, although optical brightness is fully phase-dependent, this is not always the case in the near infrared. +Temperatures of gas giants reduce over time and with distance from their stars. Lowering the temperature increases optical albedo even without clouds. At a sufficiently low temperature, water clouds form, which further increase optical albedo. At even lower temperatures, ammonia clouds form, resulting in the highest albedos at most optical and near-infrared wavelengths. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-6.md b/data/en.wikipedia.org/wiki/Exoplanet-6.md new file mode 100644 index 000000000..7173dafc3 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-6.md @@ -0,0 +1,33 @@ +--- +title: "Exoplanet" +chunk: 7/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +=== Magnetic field === +In 2014, a magnetic field around HD 209458 b was inferred from the way hydrogen was evaporating from the planet. It is the first (indirect) detection of a magnetic field on an exoplanet. The magnetic field is estimated to be about one-tenth as strong as Jupiter's. +The magnetic fields of exoplanets are thought to be detectable by their auroral radio emissions with sensitive low-frequency radio telescopes such as LOFAR, although they have yet to be found. The radio emissions could measure the rotation rate of the interior of an exoplanet, and may yield a more accurate way to measure exoplanet rotation than by examining the motion of clouds. However, the most sensitive radio search for auroral emissions, thus far, from nine exoplanets with Arecibo also did not result in any discoveries. +Earth's magnetic field results from its flowing liquid metallic core, but on massive super-Earths with high pressure, different compounds may form which do not match those created under terrestrial conditions. Compounds may form with greater viscosities and high melting temperatures, which could prevent the interiors from separating into different layers and so result in undifferentiated coreless mantles. Forms of magnesium oxide such as MgSi3O12 could be a liquid metal at the pressures and temperatures found in super-Earths and could generate a magnetic field in the mantles of super-Earths. +Hot Jupiters have been observed to have a larger radius than expected. This could be caused by the interaction between the stellar wind and the planet's magnetosphere creating an electric current through the planet that heats it up (Joule heating) causing it to expand. The more magnetically active a star is, the greater the stellar wind and the larger the electric current leading to more heating and expansion of the planet. This theory matches the observation that stellar activity is correlated with inflated planetary radii. +In August 2018, scientists announced the transformation of gaseous deuterium into a liquid metallic hydrogen form. This may help researchers better understand giant gas planets, such as Jupiter, Saturn and related exoplanets, since such planets are thought to contain a lot of liquid metallic hydrogen, which may be responsible for their observed powerful magnetic fields. +Although scientists previously announced that the magnetic fields of close-in exoplanets may cause increased stellar flares and starspots on their host stars, in 2019 this claim was demonstrated to be false in the HD 189733 system. The failure to detect "star-planet interactions" in the well-studied HD 189733 system calls other related claims of the effect into question. A later search for radio emissions from eight exoplanets that orbit within 0.1 astronomical units of their host stars, conducted by the Arecibo radio telescope also failed to find signs of these magnetic star-planet interactions. +In 2019, the strength of the surface magnetic fields of 4 hot Jupiters were estimated and ranged between 20 and 120 gauss compared to Jupiter's surface magnetic field of 4.3 gauss. +In 2023 astronomers detected what might be the first sign of magnetosphere around a rocky exoplanet in the YZ Ceti system. + +=== Plate tectonics === +In 2007, two independent teams of researchers came to opposing conclusions about the likelihood of plate tectonics on larger super-Earths with one team saying that plate tectonics would be episodic or stagnant and the other team saying that plate tectonics is very likely on super-Earths even if the planet is dry. +If super-Earths have more than 80 times as much water as Earth, then they become ocean planets with all land completely submerged. However, if there is less water than this limit, then the deep water cycle would move enough water between the oceans and mantle to allow continents to exist. + +=== Volcanism === +Large surface temperature variations on 55 Cancri e have been attributed to possible volcanic activity releasing large clouds of dust which blanket the planet and block thermal emissions. +Tidal heating caused by gravitational tug of neighboring planets might lead to the emergence of volcanic activities on a terrestrial exoplanet. + +=== Rings === + +In 2007, the star V1400 Centauri was occulted by an object (either a planet or brown dwarf) surrounded by an extensive disc of debris. The object, designated J1407b, was long believed to host a vast planetary ring system much larger than Saturn's rings. Follow-up observations found the supposed ring system could instead be a circumplanetary disk. +There is strong evidence of a ring system around HIP 41378 f, given the planet's measured radius is too large for its mass, the radius measurement might have been affected by a ring system around the planet. +The rings of the Solar System's gas giants are aligned with their planet's equator. However, for exoplanets that orbit close to their star, tidal forces from the star would lead to the outermost rings of a planet being aligned with the planet's orbital plane around the star. A planet's innermost rings would still be aligned with the planet's equator so that if the planet has a tilted rotational axis, then the different alignments between the inner and outer rings would create a warped ring system. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-7.md b/data/en.wikipedia.org/wiki/Exoplanet-7.md new file mode 100644 index 000000000..cac53a744 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-7.md @@ -0,0 +1,45 @@ +--- +title: "Exoplanet" +chunk: 8/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +=== Moons === +There is evidence that moons around other planets, commonly referred to exomoons, may exist. None has been confirmed so far. +In 2012 a candidate exomoon was detected around WASP-12b via periodic light variations in the planet's light curve. Subsequent observations found this object might actually be a trojan planet. +In December 2013, a candidate exomoon was detected in the microlensing event MOA-2011-BLG-262, it was believed to be either a 0.5 M🜨 exomoon around a Jupiter-sized free-floating planet or a Neptune-mass planet around a red dwarf, but follow-up observations confirmed the latter scenario. +On 3 October 2018, evidence suggesting a large exomoon orbiting Kepler-1625b was reported, and in 2021 evidence of an exomoon around Kepler-1708b was also reported. Their existence, however, remain doubtful, but follow-up observations may confirm these exomoons. +The detection of sodium in hot Jupiters such as WASP-76b, HD 189733 b or WASP-49b is likely due to a Io-like exomoon around these planets. + +=== Atmospheres === + +Atmospheres have been detected around several exoplanets. The first to be observed was HD 209458 b in 2001. + +As of February 2014, more than fifty transiting and five directly imaged exoplanet atmospheres have been observed, resulting in detection of molecular spectral features; observation of day–night temperature gradients; and constraints on vertical atmospheric structure. Also, an atmosphere has been detected on the non-transiting hot Jupiter Tau Boötis b. +In May 2017, glints of light from Earth, seen as twinkling from an orbiting satellite a million miles away, were found to be reflected light from ice crystals in the atmosphere. The technology used to determine this may be useful in studying the atmospheres of distant worlds, including those of exoplanets. + +==== Comet-like tails ==== +Kepler-1520b is a small rocky planet, very close to its star, that is evaporating and leaving a trailing tail of cloud and dust like a comet. The dust could be ash erupting from volcanos and escaping due to the small planet's low surface-gravity, or it could be from metals that are vaporized by the high temperatures of being so close to the star with the metal vapor then condensing into dust. +In June 2015, scientists reported that the atmosphere of GJ 436 b was evaporating, resulting in a giant cloud around the planet and, due to radiation from the host star, a long trailing tail 14 million km (9 million mi) long. + +=== Insolation pattern === +Tidally locked planets in a 1:1 spin-orbit resonance would have their star always shining directly overhead on one spot, which would be hot with the opposite hemisphere receiving no light and being freezing cold. Such a planet could resemble an eyeball, with the hotspot being the pupil. Planets with an eccentric orbit could be locked in other resonances. 3:2 and 5:2 resonances would result in a double-eyeball pattern with hotspots in both eastern and western hemispheres. Planets with both an eccentric orbit and a tilted axis of rotation would have more complicated insolation patterns. + +== Surface == + +=== Surface composition === +Surface features can be distinguished from atmospheric features by comparing emission and reflection spectroscopy with transmission spectroscopy. Mid-infrared spectroscopy of exoplanets may detect rocky surfaces, and near-infrared may identify magma oceans or high-temperature lavas, hydrated silicate surfaces and water ice, giving an unambiguous method to distinguish between rocky and gaseous exoplanets. + +=== Surface temperature === + +Measuring the intensity of the light it receives from its parent star can estimate the temperature of an exoplanet. For example, the planet OGLE-2005-BLG-390Lb is estimated to have a surface temperature of roughly −220 °C (50 K). However, such estimates may be substantially in error because they depend on the planet's usually unknown albedo, and because factors such as the greenhouse effect may introduce unknown complications. A few planets have had their temperature measured by observing the variation in infrared radiation as the planet moves around in its orbit and is eclipsed by its parent star. For example, the planet HD 189733b has been estimated to have an average temperature of 1,205 K (932 °C) on its dayside and 973 K (700 °C) on its nightside. + +== Habitability == + +As more planets are discovered, the field of exoplanetology continues to grow into a deeper study of extrasolar worlds, and will ultimately tackle the prospect of life on planets beyond the Solar System. At cosmic distances, life can only be detected if it is developed at a planetary scale and strongly modified the planetary environment, in such a way that the modifications cannot be explained by classical physico-chemical processes (out of equilibrium processes). For example, molecular oxygen (O2) in the atmosphere of Earth is a result of photosynthesis by living plants and many kinds of microorganisms, so it can be used as an indication of life on exoplanets, although small amounts of oxygen could also be produced by non-biological means. If water is a requirement for life, a habitable planet must sustain water. It must orbit a stable star at a distance within which planetary-mass objects with sufficient atmospheric pressure can support liquid water at their surfaces. + +=== Habitable zone === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-8.md b/data/en.wikipedia.org/wiki/Exoplanet-8.md new file mode 100644 index 000000000..0c033fd12 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-8.md @@ -0,0 +1,30 @@ +--- +title: "Exoplanet" +chunk: 9/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +The habitable zone around a star is the region where the temperature is just right to allow liquid water to exist on the surface of a planet under a suitable atmosphere; that is, not too close to the star for the water to evaporate and not too far away from the star for the water to freeze. The heat produced by stars varies depending on the size and age of the star, so that the habitable zone can be at different distances for different stars. Also, the atmospheric conditions on the planet influence the planet's ability to retain heat so that the location of the habitable zone is also specific to each type of planet: desert planets (also known as dry planets), with very little water, will have less water vapor in the atmosphere than Earth and so have a reduced greenhouse effect, meaning that a desert planet could maintain oases of water closer to its star than Earth is to the Sun. The lack of water also means there is less ice to reflect heat into space, so the outer edge of desert-planet habitable zones is further out. Rocky planets with a thick hydrogen atmosphere could maintain surface water much further out than the Earth–Sun distance. Planets with larger mass have wider habitable zones because gravity reduces the water cloud column depth which reduces the greenhouse effect of water vapor, thus moving the inner edge of the habitable zone closer to the star. +Planetary rotation rate is one of the major factors determining the circulation of the atmosphere and hence the pattern of clouds: slowly rotating planets create thick clouds that reflect more and so can be habitable much closer to their star. Earth with its current atmosphere would be habitable in Venus's orbit, if it had Venus's slow rotation. If Venus lost its water ocean due to a runaway greenhouse effect, it is likely to have had a higher rotation rate in the past. Alternatively, Venus never had an ocean because water vapor was lost to space during its formation and could have had its slow rotation throughout its history. +Tidally locked planets (a.k.a. "eyeball" planets) can be habitable closer to their star than previously thought due to the effect of clouds: at high stellar flux, strong convection produces thick water clouds near the substellar point that greatly increase the planetary albedo and reduce surface temperatures. +Planets in the habitable zones of stars with low metallicity are more habitable for complex life on land than high metallicity stars because the stellar spectrum of high metallicity stars is less likely to cause the formation of ozone thus enabling more ultraviolet rays to reach the planet's surface. +Habitable zones have usually been defined in terms of surface temperature, however over half of Earth's biomass is from subsurface microbes, and the temperature increases with depth, so the subsurface can be conducive for microbial life when the surface is frozen and if this is considered, the habitable zone extends much further from the star, even rogue planets could have liquid water at sufficient depths underground. In an earlier era of the universe the temperature of the cosmic microwave background would have allowed any rocky planets that existed to have liquid water on their surface regardless of their distance from a star. Jupiter-like planets might not be habitable, but they could have habitable moons. + +=== Ice ages and snowball states === + +The outer edge of the habitable zone is where planets are completely frozen, but planets well inside the habitable zone can periodically become frozen. If orbital fluctuations or other causes produce cooling, then this creates more ice, but ice reflects sunlight causing even more cooling, creating a feedback loop until the planet is completely or nearly completely frozen. When the surface is frozen, this stops carbon dioxide weathering, resulting in a build-up of carbon dioxide in the atmosphere from volcanic emissions. This creates a greenhouse effect which thaws the planet again. Planets with a large axial tilt are less likely to enter snowball states and can retain liquid water further from their star. Large fluctuations of axial tilt can have even more of a warming effect than a fixed large tilt. Counterintuitively, planets orbiting cooler stars, such as red dwarfs, are less likely to enter snowball states - because the infrared radiation emitted by cooler stars is mostly at longer wavelengths that are absorbed by ice, which heats it up. + +=== Tidal heating === +If a planet has an eccentric orbit, then tidal heating can provide another source of energy besides stellar radiation. This means that eccentric planets in the radiative habitable zone can be too hot for liquid water. Tides also circularize orbits over time, so there could be planets in the habitable zone with circular orbits that have no water because they used to have eccentric orbits. Eccentric planets further out than the habitable zone would still have frozen surfaces, but the tidal heating could create a subsurface ocean similar to Europa's. In some planetary systems, such as in the Upsilon Andromedae system, the eccentricity of orbits is maintained or even periodically varied by perturbations from other planets in the system. Tidal heating can cause outgassing from the mantle, contributing to the formation and replenishment of an atmosphere. + +=== Potentially habitable planets === + +A review in 2015 identified exoplanets Kepler-62f, Kepler-186f and Kepler-442b as the best candidates for being potentially habitable. These are at a distance of 1000, 490 and 1,120 light-years away, respectively. Of these, Kepler-186f is in similar size to Earth with its 1.2-Earth-radius measure, and it is located towards the outer edge of the habitable zone around its red dwarf star. +When looking at the nearest terrestrial exoplanet candidates, Proxima Centauri b is about 4.2 light-years away. Its equilibrium temperature is estimated to be −39 °C (234 K). +numberradius (earth radii)03006009001200150018002100r < 1r < 2r < 15numberExoplanets by radius.mw-chart-896a74a4b0f34b6a8842401bf585e3332d8b922e888c8c2658274e56223bc9d1ba872a197b5563dd794ac6c0f58a6e1753c361b8127bec60d8e3d790f2b22b57__zr634712-cls-3335393:hover{pointer-events:none}.mw-chart-896a74a4b0f34b6a8842401bf585e3332d8b922e888c8c2658274e56223bc9d1ba872a197b5563dd794ac6c0f58a6e1753c361b8127bec60d8e3d790f2b22b57__zr634712-cls-3335394:hover{cursor:pointer;fill:rgba(82,130,235,1)}.mw-chart-896a74a4b0f34b6a8842401bf585e3332d8b922e888c8c2658274e56223bc9d1ba872a197b5563dd794ac6c0f58a6e1753c361b8127bec60d8e3d790f2b22b57__zr634712-cls-3335395:hover{cursor:pointer;fill:rgba(0,0,0,0)} + +==== Earth-size planets ==== \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Exoplanet-9.md b/data/en.wikipedia.org/wiki/Exoplanet-9.md new file mode 100644 index 000000000..3478a5685 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Exoplanet-9.md @@ -0,0 +1,65 @@ +--- +title: "Exoplanet" +chunk: 10/10 +source: "https://en.wikipedia.org/wiki/Exoplanet" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:09.575486+00:00" +instance: "kb-cron" +--- + +In November 2013, it was estimated that 22±8% of Sun-like stars in the Milky Way galaxy may have an Earth-sized planet in the habitable zone. Assuming 200 billion stars in the Milky Way, that would be 11 billion potentially habitable Earths, rising to 40 billion if red dwarfs are included. +Kepler-186f, a 1.2-Earth-radius planet in the habitable zone of a red dwarf, was reported in April 2014. +Proxima Centauri b, a planet in the habitable zone of Proxima Centauri, the nearest known star to the solar system with an estimated minimum mass of 1.27 times the mass of the Earth. +In February 2013, researchers speculated that up to 6% of small red dwarfs may have Earth-size planets. This suggests that the closest one to the Solar System could be 13 light-years away. The estimated distance increases to 21 light-years when a 95% confidence interval is used. In March 2013, a revised estimate gave an occurrence rate of 50% for Earth-size planets in the habitable zone of red dwarfs. +At 1.63 times Earth's radius Kepler-452b is the first discovered near-Earth-size planet in the "habitable zone" around a G2-type Sun-like star (July 2015). +In January 2020 researchers reported the discovery of TOI-700 d, the first Earth-size planet in the habitable zone to be detected by TESS. + +== Planetary system == + +Exoplanets are often members of planetary systems of multiple planets around a star. The planets interact with each other gravitationally and sometimes form resonant systems where the orbital periods of the planets are in integer ratios. The Kepler-223 system contains four planets in an 8:6:4:3 orbital resonance. +Some hot Jupiters orbit their stars in the opposite direction to their stars' rotation. One proposed explanation is that hot Jupiters tend to form in dense clusters, where perturbations are more common and gravitational capture of planets by neighboring stars is possible. + +== Search projects == +ANDES – The ArmazoNes High Dispersion Echelle Spectrograph, a planet finding and planet characterisation spectrograph, is expected to be fitted onto ESO's ELT 39.3m telescope. ANDES was formally known as HIRES, which itself was created after a merger of the consortia behind the earlier CODEX (optical high-resolution) and SIMPLE (near-infrared high-resolution) spectrograph concepts. +CoRoT – Space telescope that found the first transiting rocky planet. +ESPRESSO – A rocky planet-finding, and stable spectroscopic observing, spectrograph mounted on ESO's 4 × 8.2 m VLT telescope, sited on the levelled summit of Cerro Paranal in the Atacama Desert of northern Chile. +HARPS – High-precision echelle planet-finding spectrograph installed on the ESO's 3.6m telescope at La Silla Observatory in Chile. +Kepler – Mission to look for large numbers of exoplanets using the transit method. +TESS – Mission to search for new exoplanets, active from 2018 to 2020 and rotating to observe stars from all over the sky. As of 22 March 2025, TESS had identified 7,525 candidate exoplanets, of which 618 had been confirmed. + +== See also == + +Detecting Earth from distant star-based systems +Extrasolar Planets Encyclopedia +Extrasolar planets in fiction +Habitable zone for complex life +Lists of exoplanets +NASA Exoplanet Archive +Planetary capture +List of planet types +Desert planet +Carbon planet +Lava planet +Eyeball planet +Ocean world +Ice planet +Hycean planet +Chthonian planet + +== Notes == + +== References == + +== Further reading == +Boss, Alan (2009). The Crowded Universe: The Search for Living Planets. Basic Books. Bibcode:2009cusl.book.....B. ISBN 978-0-465-00936-7 (Hardback); ISBN 978-0-465-02039-3 (Paperback). +Dorminey, Bruce (2001). Distant Wanderers. Springer-Verlag. ISBN 978-0-387-95074-7 (Hardback); ISBN 978-1-4419-2872-6 (Paperback). +Jayawardhana, Ray (2011). Strange New Worlds: The Search for Alien Planets and Life Beyond Our Solar System. Princeton, NJ: Princeton University Press. ISBN 978-0-691-14254-8. (Hardcover.) +van Dishoeck, Ewine F.; Bergin, Edwin A.; Lis, Dariusz C.; Lunine, Jonathan I. (2014). "Water: From Clouds to Planets". Protostars and Planets VI. p. 835. arXiv:1401.8103. Bibcode:2014prpl.conf..835V. doi:10.2458/azu_uapress_9780816531240-ch036. ISBN 978-0-8165-3124-0. S2CID 55875067. +Villard, Ray; Cook, Lynette R. (2005). Infinite Worlds: An Illustrated Voyage to Planets Beyond Our Sun. University of California Press. ISBN 978-0-520-23710-0 +Yaqoob, Tahir (2011). Exoplanets and Alien Solar Systems. New Earth Labs (Education and Outreach). ISBN 978-0-9741689-2-0. Paperback. + +== External links == + +The Extrasolar Planets Encyclopaedia (Paris Observatory) +NASA Exoplanet Archive \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Extraterrestrial_life-0.md b/data/en.wikipedia.org/wiki/Extraterrestrial_life-0.md index 91c170006..a18548608 100644 --- a/data/en.wikipedia.org/wiki/Extraterrestrial_life-0.md +++ b/data/en.wikipedia.org/wiki/Extraterrestrial_life-0.md @@ -4,7 +4,7 @@ chunk: 1/12 source: "https://en.wikipedia.org/wiki/Extraterrestrial_life" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:24.121788+00:00" +date_saved: "2026-05-05T13:16:10.940652+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Extraterrestrial_life-1.md b/data/en.wikipedia.org/wiki/Extraterrestrial_life-1.md index 8bca34e07..72831216a 100644 --- a/data/en.wikipedia.org/wiki/Extraterrestrial_life-1.md +++ b/data/en.wikipedia.org/wiki/Extraterrestrial_life-1.md @@ -4,7 +4,7 @@ chunk: 2/12 source: 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100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-1.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-1.md @@ -4,7 +4,7 @@ chunk: 2/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-10.md b/data/en.wikipedia.org/wiki/Fermi_paradox-10.md index d63665b57..0502b163e 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-10.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-10.md @@ -4,7 +4,7 @@ chunk: 11/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-11.md b/data/en.wikipedia.org/wiki/Fermi_paradox-11.md index 1c513af08..88786f129 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-11.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-11.md @@ -4,7 +4,7 @@ chunk: 12/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-2.md b/data/en.wikipedia.org/wiki/Fermi_paradox-2.md index 6eea2daff..2bf4be3c8 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-2.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-2.md @@ -4,7 +4,7 @@ chunk: 3/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-3.md b/data/en.wikipedia.org/wiki/Fermi_paradox-3.md index 497cfdac9..a93667a65 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-3.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-3.md @@ -4,7 +4,7 @@ chunk: 4/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-4.md b/data/en.wikipedia.org/wiki/Fermi_paradox-4.md index 11c494f7f..752d1a59c 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-4.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-4.md @@ -4,7 +4,7 @@ chunk: 5/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-5.md b/data/en.wikipedia.org/wiki/Fermi_paradox-5.md index 523f3b0d8..abae0e0a1 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-5.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-5.md @@ -4,7 +4,7 @@ chunk: 6/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-6.md b/data/en.wikipedia.org/wiki/Fermi_paradox-6.md index 169379bab..1884add0a 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-6.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-6.md @@ -4,7 +4,7 @@ chunk: 7/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-7.md b/data/en.wikipedia.org/wiki/Fermi_paradox-7.md index 50dc3b80e..c4a5de60e 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-7.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-7.md @@ -4,7 +4,7 @@ chunk: 8/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-8.md b/data/en.wikipedia.org/wiki/Fermi_paradox-8.md index 2c2ed3662..e3d176093 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-8.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-8.md @@ -4,7 +4,7 @@ chunk: 9/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Fermi_paradox-9.md b/data/en.wikipedia.org/wiki/Fermi_paradox-9.md index dee801f89..d16758b71 100644 --- a/data/en.wikipedia.org/wiki/Fermi_paradox-9.md +++ b/data/en.wikipedia.org/wiki/Fermi_paradox-9.md @@ -4,7 +4,7 @@ chunk: 10/12 source: "https://en.wikipedia.org/wiki/Fermi_paradox" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:01:02.535314+00:00" +date_saved: "2026-05-05T13:16:13.599327+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/First_Soviet-American_Conference_on_Communication_with_Extraterrestrial_Intelligence-0.md b/data/en.wikipedia.org/wiki/First_Soviet-American_Conference_on_Communication_with_Extraterrestrial_Intelligence-0.md new file mode 100644 index 000000000..052f3e54f --- /dev/null +++ b/data/en.wikipedia.org/wiki/First_Soviet-American_Conference_on_Communication_with_Extraterrestrial_Intelligence-0.md @@ -0,0 +1,33 @@ +--- +title: "First Soviet-American Conference on Communication with Extraterrestrial Intelligence" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/First_Soviet-American_Conference_on_Communication_with_Extraterrestrial_Intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:14.806456+00:00" +instance: "kb-cron" +--- + +First Soviet-American Conference on Communication with Extraterrestrial Intelligence was a conference held on September 5–11, 1971, at the Byurakan Observatory, USSR. The conference was jointly organized by the U.S. National Academy of Sciences (with assistance from the U.S. National Science Foundation) and the U.S.S.R. Academy of Sciences. +Organizing committee: Carl Sagan, Frank Drake, Philip Morrison, Nikolai Kardashev, Victor Ambartsumian, Iosif Shklovsky, Vsevolod Troitsky. +Notable participants: Semion Braude, Francis Crick, Freeman Dyson, Marvin Minsky, Kent V. Flannery, Vitaly Ginzburg, Thomas Gold, Sebastian von Hoerner, David H. Hubel, Kenneth Kellermann, Richard Borshay Lee, György Marx, William H. McNeill, Bernard M. Oliver, Leslie Orgel, John R. Platt, Gunther Stent, Charles Hard Townes. +As a result of the conference, the following research directions were formulated: + +A search for signals and for evidence of astroengineering activities in the radiation of a few hundred chosen nearby stars and of a limited number of other selected objects, covering the wavelength range from visible to decimeter waves, using the largest existing astronomical instruments. +A search for signals from powerful sources within galaxies of the local group, including searches for strong impulsive signals. +Exploration of the region of minimum noise in the submillimeter band, in order to determine its suitability for observing extraterrestrial civilizations. +The design, among others, of powerful new astronomical instruments with roughly the following parameters: +A decimeter wave radiotelescope with an effective area >1 km2. +A millimeter wave telescope with an effective area > 104 m2. +A submillimeter wave telescope with an effective area > 103 m2. +An infrared telescope with an effective area 102 m2. +The definition of a system for keeping the entire sky under constant surveillance, which could lead to a search of wider scope than those listed under #1 and #2. + + +== See also == +Byurakan Conference +Communication with extraterrestrial intelligence +Fermi paradox + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Firstborn_hypothesis-0.md b/data/en.wikipedia.org/wiki/Firstborn_hypothesis-0.md index 5f7ce5be0..942b6b783 100644 --- a/data/en.wikipedia.org/wiki/Firstborn_hypothesis-0.md +++ b/data/en.wikipedia.org/wiki/Firstborn_hypothesis-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Firstborn_hypothesis" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:39.796915+00:00" +date_saved: "2026-05-05T13:16:16.089889+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope-0.md b/data/en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope-0.md new file mode 100644 index 000000000..b631f1ba1 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope-0.md @@ -0,0 +1,30 @@ +--- +title: "Five-hundred-meter Aperture Spherical Telescope" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:17.242125+00:00" +instance: "kb-cron" +--- + +The Five-hundred-meter Aperture Spherical Telescope (FAST; Chinese: 五百米口径球面射电望远镜), nicknamed Tianyan (天眼, lit. "Sky's/Heaven's Eye"), is a radio telescope located in the Dawodang depression (大窝凼洼地), a natural basin in Pingtang County, Guizhou, southwestern China. FAST has a 500 m (1,640 ft) diameter dish constructed in a natural depression in the landscape. It is the world's largest single-dish telescope. +It has a novel design, using an active surface made of 4,500 metal panels which form a moving parabola shape in real time. The cabin containing the feed antenna, suspended on cables above the dish, can move automatically by using winches to steer the instrument to receive signals from different directions. It observes at wavelengths of 10 cm to 4.3 m. +Construction of FAST began in 2011. It observed first light in September 2016. After three years of testing and commissioning, it was declared fully operational on 11 January 2020. +The telescope made its first discovery, of two new pulsars, in August 2017. The new pulsars PSR J1859-01 and PSR J1931-02—also referred to as FAST pulsar #1 and #2 (FP1 and FP2), were detected on 22 and 25 August 2017; they are 16,000 and 4,100 light years away, respectively. Parkes Observatory in Australia independently confirmed the discoveries on 10 September 2017. By September 2018, FAST had discovered 44 new pulsars, and by 2021, 500. + +== History == + +The telescope was first proposed in 1994. The project was approved by the National Development and Reform Commission (NDRC) in July 2007. A 65-person village was relocated from the valley to make room for the telescope and an additional 9,110 people living within a 5 km (3 mi) radius of the telescope were relocated to create a radio-quiet area. The Chinese government spent around US$269 million in poverty relief funds and bank loans for the relocation of the local residents, while the construction of the telescope itself cost $180 million. +On 26 December 2008, a foundation-laying ceremony was held on the construction site. Construction started in March 2011, and the last panel was installed on the morning of 3 July 2016. +Originally budgeted for CN¥700 million, the final cost was CN¥1.2 billion (US$180 million). Significant difficulties encountered were the site's remote location and poor road access, and the need to add shielding to suppress radio-frequency interference (RFI) from the primary mirror actuators. The actuators were redesigned to meet shielding efficiency requirements and their installation was completed in 2015. Interference from the actuators has not been detected since. +Testing and commissioning began with first light on 25 September 2016. The first observations being done without the active primary reflector, configuring it in a fixed shape and using the Earth's rotation to scan the sky. Subsequent early science took place mainly in lower frequencies while the active surface is brought to its design accuracy; longer wavelengths are less sensitive to errors in reflector shape. It took three years to calibrate the various instruments so it can become fully operational. +Local government efforts to develop a tourist industry around the telescope are causing some concern among astronomers worried about nearby mobile telephones acting as sources of RFI. A projected 10 million tourists in 2017 will force officials to decide on the scientific mission versus the economic benefits of tourism. +The primary driving force behind the project was Nan Rendong, a researcher with the Chinese National Astronomical Observatory, part of the Chinese Academy of Sciences. He held the positions of chief scientist and chief engineer of the project. He died on 15 September 2017 in Boston due to lung cancer. +On 14 June 2022, astronomers, working with China's FAST telescope, reported the possibility of having detected artificial (presumably alien) signals, but cautioned that further studies are required to determine if some kind of natural radio interference may be the source. More recently, on 18 June 2022, Dan Werthimer, chief scientist for several SETI-related projects, noted, "These signals are from radio interference; they are due to radio pollution from earthlings, not from E.T." + +== Overview == +FAST has a reflecting surface 500 metres (1,600 ft) in diameter located in a natural sinkhole in the karst rock landscape, focusing radio waves on a receiving antenna in a "feed cabin" suspended 140 m (460 ft) above it. The reflector is made of perforated aluminium panels supported by a mesh of steel cables hanging from the rim. +FAST's surface is made of 4,450 triangular panels, 11 m (36 ft) on a side, in the form of a geodesic dome. There are 2,225 winches located underneath that make it an active surface, pulling on joints between panels, deforming the flexible steel cable support into a parabolic antenna aligned with the desired sky direction. + +Above the reflector is a lightweight feed cabin moved by a cable robot using winch servomechanisms on six support towers. The receiving antennas are mounted below this on a Stewart platform which provides fine position control and compensates for disturbances like wind motion. This produces a planned pointing precision of 8 arcseconds. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope-1.md b/data/en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope-1.md new file mode 100644 index 000000000..7de0cfce0 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope-1.md @@ -0,0 +1,57 @@ +--- +title: "Five-hundred-meter Aperture Spherical Telescope" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:17.242125+00:00" +instance: "kb-cron" +--- + +The maximum zenith angle is 40 degrees when the effective illuminated aperture is reduced to 200 m, while it is 26.4 degrees when the effective illuminated aperture is 300 m without loss. +Although the reflector diameter is 500 m (1,600 ft), held in the correct parabolic shape and "illuminated" by the receiver, only a circle of 300 m diameter is useful at any one time. The telescope can be pointed to different positions on the sky by illuminating a 300-meter section of the 500 meter aperture. (FAST has a smaller effective aperture than the Jicamarca Radio Observatory, which has a filled aperture of equivalent diameter of 338 m). +Its working frequency ranges from 70 MHz to 3.0 GHz, with the upper limit set by the precision with which the primary can approximate a parabola. It could be improved slightly, but the size of the triangular segments limits the shortest wavelength which can be received. The original plan was to cover the frequency range with 9 receivers. During the construction phase, a commissioning ultra-wide band receiver covering 260 MHz to 1620 MHz was proposed and built, which produced the first pulsar discovery from FAST. At the moment, only the FAST L-band Receiver-array of 19 beams (FLAN) is installed and is operational between 1.05 GHz and 1.45 GHz. +The Next Generation Archive System (NGAS), developed by the International Centre for Radio Astronomy Research (ICRAR) in Perth, Australia and the European Southern Observatory will store and maintain the large amount of data that it collects. +A five-kilometer zone near the telescope forbids tourists from using mobile phones and other radio-emitting devices. +An expansion has been planned to build an additional 24 radio dishes with 40 meters diameter, and forming a radio-telescope array within the surrounding area of 10KM diameter. The project should expect a boost of telescope resolution by 30 times. + +== Science mission == +The FAST website lists the following science objectives of the radio telescope: + +Large scale neutral hydrogen survey +Pulsar observations +Leading the international very long baseline interferometry (VLBI) network +Detection of interstellar molecules +Detecting interstellar communication signals (Search for extraterrestrial intelligence) +Pulsar timing arrays +The FAST telescope joined the Breakthrough Listen SETI project in October 2016 to search for intelligent extraterrestrial communications in the Universe. +In February 2020, scientists announced the first SETI observations with the telescope. +China's Global Times reported that its 500-meter (1,600 foot) FAST telescope will be open to the global scientific community starting in April 2021 (when applications will be reviewed), and becoming effective in August 2021. Foreign scientists will be able to submit applications to China's National Astronomical Observatories online. + +== Comparison with Arecibo telescope == + +The basic design of FAST is similar to the former Arecibo Telescope. Both designs had reflectors installed in natural hollows within karst limestone, made of perforated aluminium panels with a movable receiver suspended above; and both have an effective aperture smaller than the physical size of the primary. There are however significant differences in addition to the size. +First, Arecibo's dish was fixed in a spherical shape. Although it was also suspended from steel cables with supports underneath for fine-tuning the shape, they were manually operated and adjusted only during maintenance. It had a fixed spherical shape with two additional suspended reflectors in a Gregorian configuration to correct for spherical aberration. +Second, Arecibo's receiver platform was fixed in place. To support the greater weight of the additional reflectors, the primary support cables were static, with the only motorised portion being three hold-down winches which compensated for thermal expansion. The antennas could move along a rotating arm below the platform, to allow limited adjustment of azimuth, although Arecibo was not limited in azimuth, only in zenith angle: The smaller range of motion limited it to viewing objects within 19.7° of the zenith. +Third, Arecibo could receive higher frequencies. The finite size of the triangular panels making up FAST's primary reflector limits the accuracy with which it can approximate a parabola, and thus the shortest wavelength it can focus. Arecibo's more rigid design allowed it to maintain sharp focus down to 3 cm wavelength (10 GHz); FAST is limited to 10 cm (3 GHz). Improvements in position control of the secondary might be able to push that to 6 cm (5 GHz), but then the primary reflector becomes a hard limit. +Fourth, the FAST dish is significantly deeper, contributing to a wider field of view. Although 64% larger in diameter, FAST's radius of curvature is 300 m (980 ft), barely larger than Arecibo's 270 m (870 ft), so it forms a 113° arc (vs. 70° for Arecibo). Although Arecibo's full aperture of 305 m (1,000 ft) could be used when observing objects at the zenith, this was only possible with the line feed which had a very narrow frequency range and had been unavailable due to damage since 2017. Most Arecibo observations used the Gregorian feeds, where the effective aperture was approximately 221 m (725 ft) at zenith. +Fifth, Arecibo's larger secondary platform also housed several transmitters, making it one of the few instruments in the world capable of radar astronomy. (Planetary radar is also possible at the Jicamarca and Millstone and Altair observatories.) The NASA-funded Planetary Radar System allowed Arecibo to study solid objects from Mercury to Saturn, and to perform very accurate orbit determination on near-Earth objects, particularly potentially hazardous objects. Arecibo also included several NSF funded radars for ionospheric studies (ionosondes). Such powerful transmitters are too large and heavy for FAST's small receiver cabin, so it will not be able to participate in planetary defense although in principle it could serve as a receiver in a bistatic radar system. (Arecibo has been used in several multi-static experiments with an auxiliary 100 meter dish, including S-band radar experiments in the stratosphere, and ISAR mapping of Venus.) + +== See also == +Chinese space program +KARST – a 1990s Chinese proposal to host the SKA +List of telescope types +Square Kilometre Array – a proposed 1 km2 telescope array in Australia and South Africa + +== References == + +== Further reading == +Nan, R.; et al. (16 June 2002). "Kilometer-square Area Radio Synthesis Telescope – KARST" (PDF). Archived from the original (PDF) on 29 October 2006. +Jin, C. J.; Nan, R. D.; Gan, H. Q. (October 2007). "The FAST telescope and its possible contribution to high precision astrometry" (PDF). Proceedings of the International Astronomical Union. 3 (S248): 178–181. Bibcode:2008IAUS..248..178J. doi:10.1017/S1743921308018978. +Li, Di; Pan, Zhichen (30 December 2016). "The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) Project". Radio Science. 51 (7): 1060–1064. arXiv:1612.09372. Bibcode:2016RaSc...51.1060L. doi:10.1002/2015RS005877. S2CID 119363387. + +== External links == +Five-hundred-meter Aperture Spherical radio Telescope – website +Building the world's largest radio telescope – BBC News on YouTube +FAST: The World's Largest Telescope – China Icons on YouTube (25 September 2016) +The FAST Galactic Plane Pulsar Snapshot survey \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Frank_Drake-0.md b/data/en.wikipedia.org/wiki/Frank_Drake-0.md new file mode 100644 index 000000000..8dc5c77d9 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Frank_Drake-0.md @@ -0,0 +1,28 @@ +--- +title: "Frank Drake" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Frank_Drake" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:05.930510+00:00" +instance: "kb-cron" +--- + +Frank Donald Drake (May 28, 1930 – September 2, 2022) was an American astrophysicist and astrobiologist. +He began his career as a radio astronomer, studying the planets of the Solar System and later pulsars. Drake expanded his interests to the search for extraterrestrial intelligence (SETI), beginning with Project Ozma in 1960, an attempt at extraterrestrial communication. He developed the Drake equation, which attempts to quantify the number of intelligent lifeforms that could potentially be discovered. Working with Carl Sagan, Drake helped to design the Pioneer plaque, the first physical message flown beyond the Solar System, and was part of the team that developed the Voyager Golden Record. Drake designed and implemented the Arecibo message in 1974, an extraterrestrial radio transmission of astronomical and biological information about Earth. He is the father of Advanced SETI. +Drake worked at the National Radio Astronomy Observatory, Jet Propulsion Laboratory, Cornell University, University of California at Santa Cruz, and the SETI Institute. + +== Early life and education == +Born on May 28, 1930, in Chicago, Illinois, Drake showed an early interest in electronics and chemistry. His father was a chemical engineer, and his mother a music teacher. He had two younger siblings. +He enrolled at Cornell University on a Navy Reserve Officer Training Corps scholarship. Once there he began studying astronomy. His ideas about the possibility of extraterrestrial life were reinforced by a lecture from astrophysicist Otto Struve in 1951. After receiving a B.A. in Engineering Physics, Drake served briefly as an electronics officer on the heavy cruiser USS Albany. He then went on to graduate school at Harvard University from 1952 to 1955 where he received a M.S. and Ph.D. in astronomy. His doctoral advisor was Cecilia Payne-Gaposchkin. + +== Career == + +Drake began his research career as a radio astronomer, working at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia from 1958 to 1963. At NRAO, he conducted research into radio emissions from the planets of the Solar System: using the radio telescope at Green Bank, Drake discovered the ionosphere and magnetosphere of Jupiter, and observed the atmosphere of Venus. He also mapped the radio emission from the Galactic Center. Drake extended the capabilities of the under-construction Arecibo Observatory to allow it to be used for radio astronomy (it was originally designed purely for ionospheric physics). +In April 1959, Drake obtained approval from the director Otto Struve of NRAO to begin Project Ozma, a search for extraterrestrial radio communications. Initially, they agreed to keep the project secret, fearing public ridicule. However, Drake decided to publicize his project after Giuseppe Cocconi and Philip Morrison published a paper in Nature in September 1959, entitled "Searching for Interstellar Communications". Drake began his Project Ozma observations in 1960, using the NRAO 26-meter radio telescope, by searching for possible signals from the star systems Tau Ceti and Epsilon Eridani. No extraterrestrial signals were detected and the project was terminated in July 1960. After learning about Project Ozma, Carl Sagan (then a graduate student) contacted Drake, initiating a lifelong collaboration between them. + +In 1961, Drake devised the Drake equation, which attempted to estimate the number of extraterrestrial civilizations that might be detectable in the Milky Way. The Drake equation has been described as the "second most-famous equation in science", after E=mc2. +In 1963, Drake served as section chief of Lunar and Planetary Science at the Jet Propulsion Laboratory. He returned to Cornell in 1964, this time as a member of the faculty, where he would spend the next two decades. He was promoted to Goldwin Smith Professor of Astronomy in 1976. Drake served as associate director of the Cornell Center for Radiophysics and Space Research, as director of the Arecibo Observatory from 1966 to 1968, and as director of the National Astronomy and Ionosphere Center (NAIC, which includes the Arecibo facility), from its establishment in 1971 to 1981. +In 1972, Drake co-designed the Pioneer plaque with Carl Sagan and Linda Salzman Sagan. The plaque was the first physical message sent into space and intended to be understandable by any sufficiently technologically advanced extraterrestrial lifeforms that might intercept it. In 1974, Drake wrote the Arecibo message, the first interstellar message transmitted deliberately from Earth. He later served as technical director, with Carl Sagan and Ann Druyan, in the development of the Voyager Golden Record, an improved version of the Pioneer plaque which also incorporated audio recordings. +In 1984, Drake moved to the University of California at Santa Cruz (UCSC), becoming their Dean of Natural Science. The non-profit SETI Institute was founded the same year, with Drake as president of its board of trustees. Drake left his role as dean in 1988, but remained a professor at UCSC while also becoming director of the SETI Institute's Carl Sagan Center. Drake was President of the Astronomical Society of the Pacific from 1988 to 1990. From 1989 to 1992, he was chairman of the Board of Physics and Astronomy for the National Research Council. In 1991, Drake served on an expert panel assembled by the United States Department of Energy with the aim of assessing the effectiveness of various long-term nuclear waste warning messages to be implemented at New Mexico's Waste Isolation Pilot Plant. He retired from teaching in 1996 but remained emeritus professor of astronomy and astrophysics at UCSC. In 2010, Drake stepped down as director of The Carl Sagan Center but continued to serve on the SETI Institute's board of trustees. +On the subject of the search for the existence of extraterrestrial life, Drake said: "[A]s far as I know, the most fascinating, interesting thing you could find in the universe is not another kind of star or galaxy … but another kind of life." \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Frank_Drake-1.md b/data/en.wikipedia.org/wiki/Frank_Drake-1.md new file mode 100644 index 000000000..dfc1614ed --- /dev/null +++ b/data/en.wikipedia.org/wiki/Frank_Drake-1.md @@ -0,0 +1,42 @@ +--- +title: "Frank Drake" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Frank_Drake" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:05.930510+00:00" +instance: "kb-cron" +--- + +== Personal life == +Drake's hobbies included lapidary and the cultivation of orchids. +Drake married musician Elizabeth Bell in 1953; they divorced in 1976. They had three sons. In 1978, Drake married Amahl Shakhashiri, with whom he had two daughters, including science journalist Nadia Drake. +Drake died on September 2, 2022, at his home in Aptos, California, from natural causes at the age of 92. + +== Honors == +Asteroid 4772 Frankdrake is named after him. +Elected to the National Academy of Sciences in 1972 +Elected to the American Academy of Arts and Sciences in 1974. +2001 Drake award from the SETI Institute +2018 National Space Society's Space Pioneer Award for Science and Engineering +The Drake Lounge at the Green Bank Observatory is named after him + +== See also == +Lick Observatory +The Farthest, a 2017 documentary on the Voyager program +The Search for Life: The Drake Equation + +== References == + +== External links == + +Frank Drake's academic tree +"Estimating the Chances of Life Out There" Archived October 27, 2020, at the Wayback Machine – brief biography for astrobiology workshop at the NASA Ames Research Center. +Frank Drake's 2010 article on "The Origin of the Drake Equation" +"Finding Aliens 'Only a Matter of Time', Says Father of SETI" A Q&A with Frank Drake about his famous equation and the meaning of SETI, from an interview in February 2010, leading up to the 50th birthday of SETI +"Estimating the Chances of Life Out There" on YouTube A public talk by Frank Drake in the Silicon Valley Astronomy Lecture Series +2012 Interview with Frank Drake looking back on his career +2014 closertotruth.com Interview with Frank Drake looking at the question of Intelligent E.T. and a Space based Radio Telescope +"The Drake Equation" – Astronomy Cast transcript (html), Fraser Cain and Southern Illinois University Edwardsville professor, Dr. Pamela Gay, Monday February 12, 2007. (Full pdf transcript Archived June 21, 2007, at the Wayback Machine) +Frank Drake at IMDb +Frank Drake discography at Discogs \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Fugaku_(supercomputer)-0.md b/data/en.wikipedia.org/wiki/Fugaku_(supercomputer)-0.md new file mode 100644 index 000000000..c7488cbf7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Fugaku_(supercomputer)-0.md @@ -0,0 +1,64 @@ +--- +title: "Fugaku (supercomputer)" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Fugaku_(supercomputer)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:59.080118+00:00" +instance: "kb-cron" +--- + +Fugaku (Japanese: 富岳) is a petascale supercomputer at the Riken Center for Computational Science in Kobe, Japan. It started development in 2014 as the successor to the K computer and made its debut in 2020. It is named after an alternative name for Mount Fuji. +It became the fastest supercomputer in the world in the June 2020 TOP500 list as well as becoming the first ARM architecture-based computer to achieve this. At this time it also achieved 1.42 exaFLOPS using the mixed fp16/fp64 precision HPL-AI benchmark. It started regular operations in 2021. +Fugaku was superseded as the fastest supercomputer in the world by Frontier in May 2022. + + +== Hardware == +The supercomputer is built with the Fujitsu A64FX microprocessor. This CPU is based on the ARM version 8.2A processor architecture, and adopts the Scalable Vector Extensions for supercomputers. Fugaku was aimed to be about 100 times more powerful than the K computer (i.e. a performance target of 1 exaFLOPS). +The initial (June 2020) configuration of Fugaku used 158,976 A64FX CPUs joined using Fujitsu's proprietary torus fusion interconnect. An upgrade in November 2020 increased the number of processors. + + +== Software == +Fugaku uses a "light-weight multi-kernel operating system" named IHK/McKernel. The operating system uses both Linux and the McKernel light-weight kernel operating simultaneously and side by side. The infrastructure that both kernels run on is termed the Interface for Heterogeneous Kernels (IHK). The high-performance simulations are run on McKernel, with Linux available for all other POSIX-compatible services. +Fugaku uses a three-tiered storage system to provide parallel storage to the compute nodes. The first-level LLIO storage is an NVM-based file I/O accelerator co-developed by Fujitsu and RIKEN that is allocated on per-job storage basis to the compute nodes for storing temporary data with low latency. The LLIO system stages data in and out of a second-level Fujitsu Exascale File System (FEFS), which uses disk-based storage based on Lustre software to provide a large persistent high-performance filesystem, and a tape-based archive to store a large volume of infrequently accessed data. +Besides the system software, the supercomputer has run many kinds of applications, including several benchmarks. Running the mainstream HPL benchmark, used by TOP500, Fugaku is at petascale and almost halfway to exascale. Additionally, Fugaku has set world records on at least three other benchmarks, including HPL-AI; at 2.0 exaflops, the system has exceeded the exascale threshold for the benchmark. A description of that benchmark is as follows: + +The solver method of choice is a combination of LU factorization and iterative refinement performed afterwards to bring the solution back to 64-bit accuracy. The innovation of HPL-AI lies in dropping the requirement of 64-bit computation throughout the entire solution process and instead opting for low-precision (likely 16-bit) accuracy for LU, and a sophisticated iteration to recover the accuracy lost in factorization. + + +== Performance == +The reported initial performance of Fugaku was a Rmax of 416 petaFLOPS in the FP64 high performance LINPACK benchmark used by the TOP500. After the November 2020 upgrade in the number of processors, Fugaku's performance increased to a Rmax of 442 petaFLOPS. +In 2020, Fugaku also attained top spots in other rankings that test computers on different workloads, including Graph500, HPL-AI, and HPCG benchmark. No previous supercomputer has ever led all four rankings at once. +After a hardware upgrade, as of November 2020, "Fugaku increased its performance on the new mixed precision HPC-AI benchmark to 2.0 exaflops, besting its 1.4 exaflops mark recorded six months ago. These represent the first benchmark measurements above one exaflop for any precision on any type of hardware." (a 42% increase) Interestingly, the Arm A64FX core-count was only increased by 4.5%, to 7,630,848, but the measured performance rose much more on that benchmark (and the system does not use other compute capabilities, such as GPUs), and a little more on TOP500, or by 6.4%, to 442 petaflops, a new world record and widening the gap to the next computer by that much. For the HPCG benchmark, it is 5.4 times faster, at 16.0 HPCG-petaflops, than the number two system, Summit, which happens to also be second on TOP500. +As of November 2020, Fugaku's performance surpassed the combined performance of the next 4 supercomputers on the TOP500 list, and surpassed the remaining top-10 computers on the HPCG benchmark by a margin of 45%. + + +== History == +On May 23, 2019, Riken announced that the supercomputer was to be named Fugaku. In August 2019, the logo for Fugaku was unveiled; it depicts Mount Fuji, symbolising "Fugaku's high performance" and "the wide range of its users". In November 2019, the prototype of Fugaku won first place in the Green500 list. Shipment of the equipment racks to the Riken facility began on December 2, 2019, and was completed on May 13, 2020. In June 2020, Fugaku became the fastest supercomputer in the world in the TOP500 list, displacing the IBM Summit. +Fugaku has been used for research on masks related to the COVID-19 pandemic. +In May 2024, a Japanese research team released Fugaku-LLM, a 13-billion-parameter large language model with enhanced Japanese language capability that was trained on Fugaku. The project ported Megatron-DeepSpeed to Fugaku and optimized Transformer training on its CPU-based architecture. + + +== Cost == +In 2018, Nikkei reported the programme would cost ¥130 billion (c. US$1 billion). + + +== Comparison == + + +== See also == +ARM supercomputers +Aurora (supercomputer) +Frontier (supercomputer) +List of fastest computers +Summit (supercomputer) +TOP500 + + +== References == + + +== External links == +Official website (in English) +Satoshi Matsuoka - Supercomputing for Everyone, SIAG_SC(28th June 2022) (Lecture about Fugaku for general audience) +Fugaku Virtual Tour \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Giuseppe_Cocconi-0.md b/data/en.wikipedia.org/wiki/Giuseppe_Cocconi-0.md new file mode 100644 index 000000000..db823cd5f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Giuseppe_Cocconi-0.md @@ -0,0 +1,30 @@ +--- +title: "Giuseppe Cocconi" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Giuseppe_Cocconi" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:53.694007+00:00" +instance: "kb-cron" +--- + +Giuseppe Cocconi (1914–2008) was an Italian physicist who was director of the Proton Synchrotron at CERN in Geneva. +He is known for his work in particle physics and for his involvement with SETI where he wrote, "[t]he probability of success is difficult to estimate; but if we never search, the chance of success is zero." + + +== Life == +Cocconi was born in Como, Kingdom of Italy in 1914. He went to study physics at the University of Milan, and then in February 1938, went to the Sapienza University of Rome on the invitation of Edoardo Amaldi. There he met physicists Enrico Fermi and Gilberto Bernardini. With Fermi, he built a Wilson chamber to study the disintegration of mesons. In August of that year, Cocconi laid the foundation of cosmic ray research in Milan. While at Milan, Cocconi supervised Vanna Tongiorgi, who picked cosmic rays as her thesis' subject, and later married her in 1945. +In 1942, Cocconi was nominated professor at University of Catania, but was engaged by the Italian army to research infrared phenomena for the Royal Italian Air Force until the end of World War II, in late 1944. He taught at Catania until 1947, when Hans Bethe made a request that he would join Cornell University. During his stay at Cornell, Cocconi and his wife performed many experiments there and in Echo Lake located in the Rocky Mountains, where they demonstrated the galactic and extragalactic origins of cosmic rays. In 1955, he was awarded a Guggenheim Fellowship. While at Cornell he also wrote, with Philip Morrison, his most famous paper "Searching for Interstellar Communications", on the 21 cm Hydrogen line, which turned out to be of vital importance in the SETI program. +During his sabbatical of 1959–1961, Cocconi helped kick-start the Proton Synchrotron research program at CERN, and conducted a series of experiment on proton-proton scattering, and on the cross section of protons and neutrons. He also continued this research at Brookhaven National Laboratory (BNL). In 1963 he returned at CERN, and discovered with Alan Wetherell, Bert Diddens, and others, that the diffraction peak in proton-proton scattering shrunk with the increase in collision energy. This was interpreted as the "exchange of two Regge Poles", which later became known as the pomeron. +From 1967 to 1969, Cocconi was CERN's research director, and conceived the Roman pot, a type of particle detector. Then with a group led by Klaus Winter, he formed the CHARM collaboration, which worked until the 1980s, which investigated elastic electron-neutrino scattering. He retired in 1979, but kept in touch with the CERN research, and particle physics related research in general. +Cocconi died on 9 November 2008. His colleagues and friends wrote the following in his CERN's obituary: + +Giuseppe enjoyed the respect of great physicists in the world. As a man of culture and vision, he was very curious and attentive to what was going on in the world, and not only in the field of physics. Very kind and always ready to listen, straightforward but humble in his relations with his colleagues, always ready to admire other people’s success, he was happy to share his knowledge with juniors. His refusal of association with academies, and his lack of interest in prizes and honours, as well as his wish not to talk publicly, after his retirement, of his scientific life, are well known. He was a great physicist. + + +== References == + + +== External links == +Publications of G. Cocconi on SPIRES +Publications of Giuseppe Cocconi on SPIRES \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Habitable_zone-0.md b/data/en.wikipedia.org/wiki/Habitable_zone-0.md index 8f64cfc70..c3854be51 100644 --- a/data/en.wikipedia.org/wiki/Habitable_zone-0.md +++ b/data/en.wikipedia.org/wiki/Habitable_zone-0.md @@ -4,7 +4,7 @@ chunk: 1/7 source: "https://en.wikipedia.org/wiki/Habitable_zone" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:42.148987+00:00" +date_saved: "2026-05-05T13:16:22.223685+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Habitable_zone-1.md b/data/en.wikipedia.org/wiki/Habitable_zone-1.md index f1d56376b..ff4fbde2b 100644 --- a/data/en.wikipedia.org/wiki/Habitable_zone-1.md +++ b/data/en.wikipedia.org/wiki/Habitable_zone-1.md @@ -4,7 +4,7 @@ chunk: 2/7 source: "https://en.wikipedia.org/wiki/Habitable_zone" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:42.148987+00:00" +date_saved: "2026-05-05T13:16:22.223685+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Habitable_zone-2.md b/data/en.wikipedia.org/wiki/Habitable_zone-2.md index 82a370781..81e1db899 100644 --- a/data/en.wikipedia.org/wiki/Habitable_zone-2.md +++ b/data/en.wikipedia.org/wiki/Habitable_zone-2.md @@ -4,7 +4,7 @@ chunk: 3/7 source: "https://en.wikipedia.org/wiki/Habitable_zone" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:42.148987+00:00" +date_saved: "2026-05-05T13:16:22.223685+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Habitable_zone-3.md b/data/en.wikipedia.org/wiki/Habitable_zone-3.md index 326c1045d..ee534236c 100644 --- a/data/en.wikipedia.org/wiki/Habitable_zone-3.md +++ b/data/en.wikipedia.org/wiki/Habitable_zone-3.md @@ -4,7 +4,7 @@ chunk: 4/7 source: "https://en.wikipedia.org/wiki/Habitable_zone" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:42.148987+00:00" +date_saved: "2026-05-05T13:16:22.223685+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Habitable_zone-4.md b/data/en.wikipedia.org/wiki/Habitable_zone-4.md index 1e8ed921c..d17005471 100644 --- a/data/en.wikipedia.org/wiki/Habitable_zone-4.md +++ b/data/en.wikipedia.org/wiki/Habitable_zone-4.md @@ -4,7 +4,7 @@ chunk: 5/7 source: "https://en.wikipedia.org/wiki/Habitable_zone" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:42.148987+00:00" +date_saved: "2026-05-05T13:16:22.223685+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Habitable_zone-5.md b/data/en.wikipedia.org/wiki/Habitable_zone-5.md index f9e6e4fcf..3c3a61221 100644 --- a/data/en.wikipedia.org/wiki/Habitable_zone-5.md +++ b/data/en.wikipedia.org/wiki/Habitable_zone-5.md @@ -4,7 +4,7 @@ chunk: 6/7 source: "https://en.wikipedia.org/wiki/Habitable_zone" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:42.148987+00:00" +date_saved: "2026-05-05T13:16:22.223685+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Habitable_zone-6.md b/data/en.wikipedia.org/wiki/Habitable_zone-6.md index 2605e049d..3e2b53af2 100644 --- a/data/en.wikipedia.org/wiki/Habitable_zone-6.md +++ b/data/en.wikipedia.org/wiki/Habitable_zone-6.md @@ -4,7 +4,7 @@ chunk: 7/7 source: "https://en.wikipedia.org/wiki/Habitable_zone" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T11:09:42.148987+00:00" +date_saved: "2026-05-05T13:16:22.223685+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Harris_Schurmeier-0.md b/data/en.wikipedia.org/wiki/Harris_Schurmeier-0.md new file mode 100644 index 000000000..936e555c8 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Harris_Schurmeier-0.md @@ -0,0 +1,56 @@ +--- +title: "Harris Schurmeier" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Harris_Schurmeier" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:56.237346+00:00" +instance: "kb-cron" +--- + +Harris McIntosh Schurmeier (July 4, 1924 – November 23, 2013) was an American aerospace engineer at the Jet Propulsion Laboratory, best known as the project manager of the Ranger lunar program and Voyager program to the outer planets. After the first six Ranger spacecraft failed, Schurmeier implemented new quality control and testing procedures that led to three consecutive successful missions from 1964 to 1965. He later served as Voyager's first project manager from 1972 to 1976. + + +== Early life and career == +Harris McIntosh Schurmeier was born in St. Paul, Minnesota on July 4, 1924. His father was "a pickle manufacturer". The family moved to Winnetka, Illinois when he was a teenager. Schurmeier wanted to become either a pilot or an engineer. He enrolled at Caltech in 1942; in 1945 he received a BS in mechanical engineering and in 1947 became a US Navy pilot. He returned to Caltech and received MS (1948) and engineering degree (1949) in aeronautical engineering. +He worked on wind tunnels, and in 1949 was hired by the JPL to calibrate its new 12-inch supersonic tunnel. He then worked on a design of a 20-inch hypersonic tunnel. In 1960, Schurmeier became the head of the newly created Systems Division; he described its tasks as "all the trajectory work and analytical navigation work ... preliminary design and the design integration of the spacecraft, the job of integration of the spacecraft to the launch vehicle, the responsibility for carrying out the system testing and launch operations and flight operations". +Schurmeier was assigned as a project manager for the failing Ranger Lunar program. The first five Rangers failed, and Schurmeier replaced James Burke with a mandate to change the program. To fix the program, Schurmeier established an independent Quality Assurance Office of 150 personnel and adopted "Mariner's failure reporting system" and its system of "engineering change control and design freezes". Ranger 6 failed, but the next mission, Ranger 7, succeeded and transmitted thousands of photographs; the program continued with successful Ranger 8 and 9 missions. +During the launch of Ranger 7, either Schurmeier or the mission trajectory engineer, Dick Wallace, gave peanuts to the team, nervous about a failure; after the mission success, "lucky peanuts" became a JPL tradition: + +He figured that chewing on something or just fidgeting with them on the table would give his team something else to focus on. Everyone knew that another failure might kill Ranger and JPL. Distraction was key. With peanuts on desks and in hands, engineers watched as telemetry from the spacecraft came back. ... The stunning success of Ranger 7 had nothing to do with peanuts, but it's been a tradition for the legume to be on hand for every major mission event — launches, landings, and orbit insertion burns. +After that Schurmeier became the project manager for the Mariner 6 and 7 missions to Mars (1969); then a project manager for Voyager program mission to the outer Solar System (1972–1976). He invited Caltech professor Edward C. Stone to become Voyager's project scientist; Stone held this role for 50 years, from 1972 to 2022. +Louis Friedman, a friend of both Stone and Schurmeier, who was involved in the Grand Tour program planning before it was transformed into Voyager, acknowledged Schurmeier's role in the program + +Bud Schurmeier was a phenomenal person. He is the one who made the mission happen – he and his teams: spacecraft and mission. Ed without Bud wouldn't have done anything, and Bud without Ed wouldn't have achieved the great results. But either of them without the support of the rest of the teams would also have not been able to do it alone. Voyager has many heroes. None, more than Bud Schurmeier. +In April 1976, before the Voyagers were launched, Schurmeier was promoted to JPL's assistant laboratory director for civil systems, which later became JPL's Defense and Civil Programs. Schurmeier led it until his retirement in 1985. +Schurmeier remained active after his retirement: he was on the Galileo mission's standing review board, on the W. M. Keck Observatory project review board, and participated in The Planetary Society's projects (Mars Balloon, Mars Rover), and was a leading systems engineer for its solar sail proof-of-concept Cosmos 1 and LightSail projects. + + +== Personal life == + +Schurmeier was described in 1964 as "[the one] who looks, behaves and thinks much like a ground-bound astronaut", who had "a cheerful, softspoken, unassuming personality that nevertheless is incisive and imperturbable". JPL director William H. Pickering once called Schurmeier "a very well behaved young man". +Schurmeier was an experienced pilot, flight instructor, motor gliderist, a surfer, a skier, and a sailor. In 1964, The New York Times article described his hobbies as: "he is a leader of a laboratory clique known as "The Syndicate". Its members spent weekends on such projects as building "hot-rod" catamaran boats loaded, often to the dunking point, with mast and sail." +After retirement, he became an avocado farmer and a utilities commissioner in Oceanside, California. He met his wife Betty Jo Parris in 1949, when she was a mathematician working on a wind tunnel; she died in 2009. They had four children. + + +== Awards == +1965 NASA Exceptional Scientific Achievement Medal +1969 NASA Exceptional Service Medal +1973 a fellow of the American Institute of Aeronautics and Astronautics +1981 NASA Distinguished Service Medal +1983 elected to the National Academy of Engineering +He was also a member of the Supersonic Tunnel Association, the American Association for the Advancement of Science, and Sigma Xi. + + +== Selected publications == +Schurmeier, H. (1968). "The mission of Mariner Mars '69". 5th Annual Meeting and Technical Display. doi:10.2514/6.1968-1050. +Schurmeier, H. (January 1974). Management and design of long-life systems; Proceedings of the Symposium, Denver, Colo., April 24–26, 1973. +Schurmeier, H. M. (1975). "Planetary exploration - Earth's new horizon /12th von Karman Lecture/". Journal of Spacecraft and Rockets. 12 (7): 385–405. doi:10.2514/3.27843. +Burke, James D.; Schurmeier, Harris M. (2012). "Chapter 10. Ranger: Circumstances, Events, Legacy". In Linda Billings (ed.). 50 Years of Solar System Exploration. Historical Perspectives. NASA. + + +== References == + + +== External links == + Media related to Harris Schurmeier at Wikimedia Commons \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Hart–Tipler_conjecture-0.md b/data/en.wikipedia.org/wiki/Hart–Tipler_conjecture-0.md index 67164eed5..ef45bba26 100644 --- a/data/en.wikipedia.org/wiki/Hart–Tipler_conjecture-0.md +++ b/data/en.wikipedia.org/wiki/Hart–Tipler_conjecture-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Hart–Tipler_conjecture" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:59:44.243522+00:00" +date_saved: "2026-05-05T13:16:23.500366+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/James_Burke_(space_engineer)-0.md b/data/en.wikipedia.org/wiki/James_Burke_(space_engineer)-0.md new file mode 100644 index 000000000..3ecf76fa8 --- /dev/null +++ b/data/en.wikipedia.org/wiki/James_Burke_(space_engineer)-0.md @@ -0,0 +1,49 @@ +--- +title: "James Burke (space engineer)" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/James_Burke_(space_engineer)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:55.047455+00:00" +instance: "kb-cron" +--- + +James Donahue Burke (September 18, 1925 – August 19, 2023) was an American lunar settlement and exploration expert. He was known for being the first manager of the Ranger program, and considered one of the pioneers of America's space program. + + +== Early life and career == +James Donahue Burke was born in Los Angeles County on September 18, 1925. He grew up in Claremont, California and graduated from Webb High School in 1942. +In 1945, after graduating in mechanical engineering from California Institute of Technology, he became a U.S. naval aviator. Burke returned to Caltech to receive his MSc in aeronautics, before working for JPL in 1949. +In his time at JPL, Burke was the Vega program director, developing the third stage of the general-purpose Vega launch vehicle, which was based on the Atlas rocket. +Following JPL's transfer from the U.S. Navy to NASA, and reorganization during early 1960, the Lunar and Planetary Program was created. Burke was named deputy of the Lunar Program under Clifford Cummings, before becoming the Ranger Spacecraft Project Manager as well. + + +== Ranger program == + +Burke was the first program manager of the Ranger program, a series of unmanned space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface of the Moon. The Ranger spacecraft were designed to take images of the lunar surface, transmitting those images to Earth until the spacecraft were destroyed upon impact. Burke was in charge of spacecraft design, deep space tracking and control network, space flight operations and data reduction support systems, while the Space Science Division was in charge of the scientific experiments. Burke could combine the technological and theoretical to integrate mechanical and electrical features to achieve the difficult technical objectives. Along with his two associates, Burke had solved the major guidance problem, velocity control, associated with solid-propellant ballistic missiles. He was recognized as one of the laboratory's most perceptive research engineers, and advanced to become deputy to Cummings on the Vega Program. +Technical challenges led to the failure of the first six flights. Following the first five failures, Harris M. Schurmeier became project manager. The ranger program suffered an additional failure before Ranger 7 was successful. +Burke participated in many other lunar, planetary, and astrophysical projects. He was a member of the human-powered flight team that won the Kremer prize. +Burke continued to work at JPL until his retirement in 2001. +Minor planet 4874 Burke, discovered by Eleanor Helin, was named after him when he retired from JPL. + + +== Outreach and education == +Burke was a faculty member of the International Space University from 1989. +Burke and his wife Caroline were advisers at the founding conference of the Space Generation Advisory Council during UNISPACE III in Vienna and participated in many Space Generation activities. Burke was an honorary board member of SGAC. +Burke was involved with the Planetary Society from the beginning. He was the technical editor of newsletter, "The Planetary Report" for many years. + + +== Death == +James Burke died on August 19, 2023, at the age of 97. + + +== Selected publications == +Burke had over 129 works in 165 publications + +Burke, J, Brereton, R, Muller, P. 1970," Desert Stream Channels resembling Lunar Sinuous Rilles". In Nature, Vol. 225, 23 March, pp1234–1236, (28 March 1970); doi:10.1038/2251234a0 +Burke, J. 1985, "Merits of a Lunar Polar Base Location". In Mendell, W. (Ed.). Lunar Bases and Space Activities of the 21st Century, Lunar and Planetary Institute. +Burke, J. 2001, "Moon". In Encyclopædia Britannica, 24th edition. +Burke, J. 2008, "Moon". In McGraw-Hill Encyclopedia of Science and Technology, 10th ed. + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/John_Billingham-0.md b/data/en.wikipedia.org/wiki/John_Billingham-0.md new file mode 100644 index 000000000..74d3fd87a --- /dev/null +++ b/data/en.wikipedia.org/wiki/John_Billingham-0.md @@ -0,0 +1,30 @@ +--- +title: "John Billingham" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/John_Billingham" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:41.449528+00:00" +instance: "kb-cron" +--- + +Dr. John Billingham, BM BCh, (March 18, 1930 – August 4, 2013) was a British Physician and later director of the SETI Program Office and Director of the Life Sciences Division at the NASA Ames Research Center in the USA. After retiring from NASA he became a Trustee of the SETI Institute Board of Directors. +He was born in Worcester, England in 1930 and educated at the Royal Grammar School Worcester. From there he went on to University College, Oxford to study physiology. He gained a BM BCh degree from Oxford and Guy's Hospital, London (which is equivalent to an M.D. in the US). He served as a medical officer with the Royal Air Force (RAF) for seven years, rising to the rank of Squadron Leader (equivalent to Major in the USAF). In 1963, he was invited to join NASA’s Lyndon B. Johnson Space Center in Houston, Texas, where he headed the Environmental Physiology Branch, and worked on the Mercury, Gemini and Apollo programs. +In 1965 he moved to the NASA Ames Research Center in California, where he headed up the Biotechnology Division, then the Extraterrestrial Research Division, and later the Life Science Division. In 1977 he appeared in the television documentary Mysteries of the Gods hosted by William Shatner to outline the projected search for extraterrestrial life that would later become Project Cyclops. +In 2009 he was inducted into the NASA Ames Hall of Fame where he was recognized for his efforts as the Father of SETI in NASA. After retiring from NASA he joined the SETI Institute as Senior Scientist, and in 1995 he became a Member of the SETI Institute's Board of Trustees, serving a term as Vice-Chair. He was also one of the people behind Project Cyclops. +He died at the age of 83 in Grass Valley, California in August 2013. + + +== References == + + +== External links == +Search for Extraterrestrial Intelligence (SETI)",1993, NASA Technical Reports Server +A reply from earth - A proposed approach to developing a message from humankind to extraterrestrial intelligence after we detect them",1990, NASA Technical Reports Server +The Evolution of Complex Life", 1989, NASA Technical Reports Server +Cultural aspects of SETI", 1991, NASA Technical Reports Server +Detection of the earth with the SETI microwave observing system assumed to be operating out in the Galaxy", 1991, NASA Technical Reports +An overview of selected biomedical aspects of Mars missions ", 1989, NASA Technical Reports Server +"Billingham, John (1930- August 4, 2013)". Internet Encyclopedia of Science. David Darling. Retrieved 18 April 2009. +'Father of SETI' at NASA, John Billingham astrobio.net +Remembering John Billingham centauri-dreams.org, Retrieved 2013-08-09. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/K_computer-0.md b/data/en.wikipedia.org/wiki/K_computer-0.md new file mode 100644 index 000000000..61cdab324 --- /dev/null +++ b/data/en.wikipedia.org/wiki/K_computer-0.md @@ -0,0 +1,67 @@ +--- +title: "K computer" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/K_computer" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:00.235974+00:00" +instance: "kb-cron" +--- + +The K computer – named for the Japanese word/numeral "kei" (京), meaning 10 quadrillion (1016) – was a supercomputer manufactured by Fujitsu, installed at the Riken Advanced Institute for Computational Science campus in Kobe, Hyōgo Prefecture, Japan. The K computer was based on a distributed memory architecture with over 80,000 compute nodes. It was used for a variety of applications, including climate research, disaster prevention and medical research. The K computer's operating system was based on the Linux kernel, with additional drivers designed to make use of the computer's hardware. +In June 2011, TOP500 ranked K the world's fastest supercomputer, with a computation speed of over 8 petaflops, and in November 2011, K became the first computer to top 10 petaflops. It had originally been slated for completion in June 2012. In June 2012, K was superseded as the world's fastest supercomputer by the American IBM Sequoia. +As of November 2018, the K computer held third place for the HPCG benchmark. It held the first place until June 2018, when it was superseded by Summit and Sierra. +The K supercomputer was decommissioned on 30 August 2019. In Japan, the K computer was succeeded by the Fugaku supercomputer, in 2020, which took the top spot on the June 2020 TOP500 list, at that time nearly three times faster than second most powerful supercomputer. + + +== Performance == +On 20 June 2011, the TOP500 Project Committee announced that K had set a LINPACK record with a performance of 8.162 petaflops, making it the fastest supercomputer in the world at the time; it achieved this performance with a computing efficiency ratio of 93.0%. The previous record holder was the Chinese National University of Defense Technology's Tianhe-1A, which performed at 2.507 petaflops. The TOP500 list is revised semiannually, and the rankings change frequently, indicating the speed at which computing power is increasing. In November 2011, Riken reported that K had become the first supercomputer to exceed 10 petaflops, achieving a LINPACK performance of 10.51 quadrillion computations per second with a computing efficiency ratio of 93.2%. K received top ranking in all four performance benchmarks at the 2011 HPC Challenge Awards. +On 18 June 2012, the TOP500 Project Committee announced that the California-based IBM Sequoia supercomputer replaced K as the world's fastest supercomputer, with a LINPACK performance of 16.325 petaflops. Sequoia is 55% faster than K, using 123% more CPU processors, but is also 150% more energy efficient. +On the TOP500 list, it became first in June 2011, falling down through time to lower positions, to eighteenth in November 2018. +K computer held third place in the HPCG benchmark test proposed by Jack Dongarra, with 0.6027 HPCG PFLOPS in November 2018. + + +== Specifications == + + +=== Node architecture === +The K computer comprised 88,128 2.0 GHz eight-core SPARC64 VIIIfx processors contained in 864 cabinets, for a total of 705,024 cores, manufactured by Fujitsu with 45 nm CMOS technology. Each cabinet contained 96 computing nodes, in addition to six I/O nodes. Each computing node contained a single processor and 16 GB of memory. The computer's water cooling system was designed to minimize failure rate and power consumption. + + +=== Network === +The nodes were connected by Fujitsu's proprietary torus fusion (Tofu) interconnect. + + +=== File system === +The system adopted a two-level local/global file system with parallel/distributed functions, and provided users with an automatic staging function for moving files between global and local file systems. Fujitsu developed an optimized parallel file system based on Lustre, called the Fujitsu Exabyte File System (FEFS), which is scalable to several hundred petabytes. + + +=== Power consumption === +Although the K computer reported the highest total power consumption (9.89 MW – the equivalent of almost 10,000 suburban homes) on the June 2011 TOP500 list, it is relatively efficient, achieving 824.6 GFlop/kW. This is 29.8% more efficient than China's NUDT TH MPP (ranked #2 in 2011), and 225.8% more efficient than Oak Ridge's Jaguar-Cray XT5-HE (ranked #3 in 2011). However, K's power efficiency still fell far short of the 2097.2 GFlops/kWatt supercomputer record set by IBM's NNSA/SC Blue Gene/Q Prototype 2. For comparison, the average power consumption of a TOP 10 system in 2011 was 4.3 MW, and the average efficiency was 463.7 GFlop/kW. +According to TOP500 compiler Jack Dongarra, professor of electrical engineering and computer science at the University of Tennessee, the K computer's performance equaled "one million linked desktop computers". The computer's annual running costs were estimated at US$10 million. + + +== K Computer Mae rapid transit station == +On 1 July 2011, Kobe's Port Island Line rapid transit system renamed one of its stations from "Port Island Minami" to "K Computer Mae" (meaning "In front of K Computer") denoting its vicinity. In June 2021, after the decommissioning of K computer, the station was renamed as Keisan Kagaku Center Station. + + +== See also == +PRIMEHPC FX10 +Supercomputing in Japan +Graph500 + + +== Notes == + + +== References == + + +== External links == + +Riken Advanced Institute for Computational Science +Riken Next-Generation Supercomputer R&D Center +K computer: Fujitsu Global +Fujitsu Scientific & Technical Journal, July 2012 (Vol. 48, No. 3, The K computer +Special Interview: Taking on the Challenge of a 10-Petaflop Computer, Riken News, No. 298, April 2006. +June 2017 Top 500 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Kent_Cullers-0.md b/data/en.wikipedia.org/wiki/Kent_Cullers-0.md new file mode 100644 index 000000000..7230a885e --- /dev/null +++ b/data/en.wikipedia.org/wiki/Kent_Cullers-0.md @@ -0,0 +1,28 @@ +--- +title: "Kent Cullers" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Kent_Cullers" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:59.795296+00:00" +instance: "kb-cron" +--- + +Kent Cullers (July 21, 1949 – July 17, 2021) was an American astronomer, who was a manager of SETI's Project Phoenix. In 2005, he retired from the SETI Institute. + + +== Early life and education == +Cullers was born in July 1949 in El Reno, Oklahoma, the son of an oil field engineer. His birth was premature and to save his life he was placed in an incubator filled with pure oxygen. The excess oxygen damaged his retinas, leaving him totally blind. His father, a physicist, read astronomy books to Cullers as a child, influencing his later aspirations. He grew up in Temple City, California, where he was a highly ranked student. He first studied psychology at Pomona College, but against great resistance changed his major to physics midway through college. He received his PhD. in physics from the University of California, Berkeley in 1980. He is the first totally blind physicist in the United States, and is believed to be the first astronomer who was blind from birth (although some astronomers have become blind in their old age, most notably Galileo Galilei). + + +== Career == +Kent Cullers worked for NASA's Search for Extraterrestrial Intelligence (SETI) program upon graduating from Berkeley. From 1985 to 1990, he was the Targeted Search Signal Detection Team Leader with the SETI Institute. He developed advanced computer algorithms for detection of continuous and pulsed signals originating from distant Earth-like planets. + +From 1990 to March 1994, he was the signal detection subsystem manager for the High Resolution Microwave Survey (HRMS) Project at NASA Ames Research Center, Moffett Field, California. He supervised the development of hardware and software for signal detection for HRMS. From 1993 to March 1994, Cullers led the SETI Research & Technology effort and managed the upgrading and replication of all the digital data processing equipment for HRMS. NASA's HRMS Project was cancelled by the United States Congress in October 1993, but Cullers still participated in Project Phoenix, the SETI Institute's continuation of the Targeted Search portion of HRMS. He resigned from NASA in October 1995, and rejoined the SETI Institute as a senior scientist and project manager for Project Phoenix. Cullers retired from the SETI Institute in 2005. Minor planet 35056 Cullers is named in his honor. + + +== In popular culture == +Cullers was the subject of a short documentary film produced by his wife, the photographer Lisa Powers. The character Kent Clark, portrayed by William Fichtner in the 1997 film Contact, was based on Cullers. + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Laurance_Doyle-0.md b/data/en.wikipedia.org/wiki/Laurance_Doyle-0.md new file mode 100644 index 000000000..436c81f5a --- /dev/null +++ b/data/en.wikipedia.org/wiki/Laurance_Doyle-0.md @@ -0,0 +1,44 @@ +--- +title: "Laurance Doyle" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Laurance_Doyle" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:03.474166+00:00" +instance: "kb-cron" +--- + +Laurance R. Doyle (born 1953) is an American scientist who received his Ph.D. from the Ruprecht Karl University of Heidelberg. +Doyle has worked at the SETI Institute since 1987 where he is a principal investigator and astrophysicist. His main area of study has been the formation and detection of extrasolar planets, but he has also worked on communications theory. In particular he has written on how patterns in animal communication relate to humans with an emphasis on cetaceans. + + +== Early life == +Doyle grew up on a dairy farm in Cambria, California and therefore, didn't have much access to information about stars. But by reading books at the local library, Doyle was able to develop his knowledge in astronomy, and eventually obtain his Bachelor's and Master's of Science degrees in astronomy from San Diego State University. + + +== Career == +His first job was at the Jet Propulsion Laboratory as an imaging engineer, where he was in charge of analyzing pictures of Jupiter and Saturn sent from the spacecraft Voyager. He moved to Heidelberg, Germany, to help analyze images of Halley's Comet. He got his doctorate in Astrophysics at the University of Heidelberg. +In 2011, Doyle led the team which discovered Kepler-16b, the first confirmed circumbinary planet, nicknamed "Tatooine" after the fictional planet from Star Wars. +Doyle is currently seeking to compare dolphin whistles and baby babble in an attempt to make predictions about extraterrestrial communications. He believes that by measuring the complexity of communications for different species on Earth, we could get a good indication of how advanced an extraterrestrial signal is using an application of Zipf's law. His study determined that babies babble over 800 different sounds with the same amount of frequency as dolphins. As they grow older, those sounds decrease to around 50 and become more repetitious. The study found that baby dolphins develop similarly in regards to their whistling. +Doyle is faculty at Principia College and the founding Director of Principia College's Institute for the Metaphysics of Physics, founded in 2014. + + +== In popular culture == +In May 2005, he appeared on a National Geographic Channel special titled Extraterrestrial. In 2012, he appeared in the episode "Will We Survive First Contact," of The Science Channel series Through the Wormhole narrated by Morgan Freeman. + + +== Selected works == +Reflections of a SETI Scientist (2022) + + +== References == + + +== External links == + +NASA workshop +Paper he co-authored on communications at the Wayback Machine (archived September 3, 2006) +Essay by him on Space.com about whales +SETI Profile +Profile of the Drake equation led by Doyle +Wired article \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/MDGRAPE-4-0.md b/data/en.wikipedia.org/wiki/MDGRAPE-4-0.md new file mode 100644 index 000000000..6d8abe825 --- /dev/null +++ b/data/en.wikipedia.org/wiki/MDGRAPE-4-0.md @@ -0,0 +1,18 @@ +--- +title: "MDGRAPE-4" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/MDGRAPE-4" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:01.419376+00:00" +instance: "kb-cron" +--- + +MDGRAPE-4 is a supercomputer under development at the RIKEN Quantitative Biology Center (QBiC) in Suita, Osaka, Japan. + + +== See also == +RIKEN MDGRAPE-3 + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Mike_Melvill-0.md b/data/en.wikipedia.org/wiki/Mike_Melvill-0.md new file mode 100644 index 000000000..b69daf0fc --- /dev/null +++ b/data/en.wikipedia.org/wiki/Mike_Melvill-0.md @@ -0,0 +1,39 @@ +--- +title: "Mike Melvill" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Mike_Melvill" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:21.428726+00:00" +instance: "kb-cron" +--- + +Michael Winston Melvill (November 30, 1940 – March 19, 2026) was a South African-born American world-record-breaking pilot and one of the test pilots for SpaceShipOne, the experimental spaceplane developed by Scaled Composites. Melvill piloted SpaceShipOne on its first flight past the edge of space, flight 15P on June 21, 2004, thus becoming the first commercial astronaut, and the 435th person to go into space. He was also the pilot on SpaceShipOne's flight 16P, the first competitive flight in the Ansari X Prize competition. + + +== Life and career == + +Michael Winston Melvill was born in Johannesburg, South Africa on November 30, 1940. +In 1978, Melvill met aerospace designer and Scaled Composites founder Burt Rutan when he flew to California to show Rutan the VariViggen he had built at his home. Rutan then hired him on the spot. In 1982, he was named Rutan's lead test pilot. +Melvill was a founding member of the team that made the Rutan Voyager around the world aircraft. He is the only person other than Voyager's crew, Dick Rutan and Jeana Yeager, to have flown the aircraft. +In 1997, Melvill and Dick Rutan, Burt's brother, flew two Long-EZ aircraft that they built side-by-side around the world. This "around the world in 80 nights" flight was called The Spirit of EAA Friendship World Tour, and some legs of it lasted for over 14 hours. +His famous 2004 flights in SpaceshipOne earned him and the entire project team the Ansari X Prize of $10 million and helped spur the beginning of the global private space race. +Later in his career, he became Vice President/General Manager at Scaled Composites. +He held FAA Commercial certificate, ASEL, AMEL, instrument airplane, rotorcraft-helicopter, glider and then astronaut. +Melvill died on March 19, 2026, at the age of 85. + + +== Awards and achievements == + +As of January, 2020, Melvill is the sole or joint holder of ten FAI aviation world records in various categories. +Melvill was awarded the Iven C. Kincheloe Award in 1999 for high altitude, developmental flight-testing of the model 281 Proteus aircraft. +Through SpaceShipOne flight 15P in 2004, he is known as the first privately funded human spaceflight mission pilot to reach space. + + +== References == + + +== External links == +"Biography at Scaled Composites". Scaled Composites. Archived from the original on April 24, 2016. +Melvill, Mike. "Mike and Dick's round the world EAA friendship tour". earthrounders.com. Archived from the original on July 19, 2014. +Boyle, Alan (June 18, 2004). "First private space pilot 'ready to go'". NBC News. Archived from the original on April 28, 2021. Retrieved August 2, 2010. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Peter_Siebold-0.md b/data/en.wikipedia.org/wiki/Peter_Siebold-0.md new file mode 100644 index 000000000..5599813f1 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Peter_Siebold-0.md @@ -0,0 +1,36 @@ +--- +title: "Peter Siebold" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Peter_Siebold" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:25.121955+00:00" +instance: "kb-cron" +--- + +Peter Siebold (born 1971) is a member of the Scaled Composites astronaut team. He is their Vice President of Flight Operations, and was one of the test pilots for SpaceShipOne and SpaceShipTwo, the experimental spaceplanes developed by the company. On April 8, 2004, Siebold piloted the second powered test flight of SpaceShipOne, flight 13P, which reached a top speed of Mach 1.6 and an altitude of 32.0 kilometres (105,000 ft). On October 31, 2014, Siebold and Michael Alsbury were piloting the SpaceShipTwo VSS Enterprise on flight PF04, when the craft came apart in mid-air and then crashed, killing Alsbury and injuring Siebold. +Siebold is, to date, the only person in human history to survive an in-flight spacecraft breakup, having fallen 50,000 feet (15,000 m) upon breakup, with his parachute deploying automatically at about 20,000 feet. + + +== Career == +Peter Siebold, a 1990 graduate of Davis Senior High School in Davis, California, obtained his pilot's license at age 16. He has been a design engineer at Scaled Composites since 1996. Siebold holds a degree in aerospace engineering from California Polytechnic University at San Luis Obispo, from 2001. +Siebold was responsible for the simulator, navigation system, and ground control system for the SpaceShipOne project at Scaled. Although he was one of four qualified pilots for SpaceShipOne, Siebold did not pilot the craft during the flights later in 2004 to meet the requirements of the Ansari X Prize. Although Siebold flew SpaceShipOne to an altitude of 32 kilometres (20 mi), he did not cross the 100 km Kármán line—the international standard for reaching space. +For his contribution to the SpaceShipOne project, Siebold, along with Mike Melvill and Brian Binnie, received the 2004 Iven C. Kincheloe Award presented by the Society of Experimental Test Pilots. +Siebold became the Director of Flight Operations at Scaled. He was the pilot who flew the White Knight Two on its maiden flight on December 21, 2008. He won the Iven C. Kincheloe Award a second time in 2009, this time individually, for his work on the first WhiteKnightTwo, VMS Eve, as chief test pilot. + + +=== SpaceShipTwo VSS Enterprise crash === + +On October 31, 2014, Siebold was one of the two pilots flying the Virgin Galactic SpaceShipTwo, VSS Enterprise, along with Michael Alsbury, on a test flight, which suffered an anomaly, resulting in the death of Alsbury and loss of Enterprise. VSS Enterprise crashed in the California Mojave Desert. Thrown clear of the Enterprise when it broke up in mid-air, Siebold survived a descent from about 50,000 feet (15,000 m) at Mach 1 speed with just a flightsuit. His parachute deployed automatically at about 20,000 feet (6,100 m), and, after landing, he was taken to the hospital for treatment. He suffered from eyesight degradation and eye pains. He was unable to keep his eyes open and he did not open his right eye until emergency personnel arrived. +Siebold's flight suit was saturated with blood from bleeding in his right arm. He did not feel any lower body injuries. As Siebold removed his parachute harness a "clunking noise" was felt in his chest and Siebold became concerned about a potential spinal fracture. Upon arrival at the ER his flight suit was cut away. +Siebold experienced a non-compound four-part fracture of his right humerus. The ball of his ankle was also dislocated and fractured. He had a non-displaced fracture of his right clavicle, a small gash in his right elbow (source of the blood on his flight suit), a deep scrape on his right wrist, and multiple scrapes on the back of his right shoulder. There was considerable bruising on his right chest but he did not know how it occurred. He did not recall any bruising on his left side. He had an abrasion under his chin which he felt was consistent with the location of his chin strap, and had multiple contusions and scrapes on his face. He was diagnosed with corneal scratches and doctors removed a piece of fiberglass from his left eye during a hospital stay. The eyes did not improve so he saw an ophthalmologist after being discharged. The ophthalmologist removed some foreign matter from his left eyelid and a "silver sliver" from his right cornea. His eyes improved immediately post procedure. + + +== References == + + +== External links == +Scaled Composites biography Archived January 11, 2010, at the Wayback Machine +Biography on Encyclopedia Astronautica +List of American Astronauts +Report by Space.com on Siebold's successful escape from VSS Enterprise \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/RIKEN_Brain_Science_Institute-0.md b/data/en.wikipedia.org/wiki/RIKEN_Brain_Science_Institute-0.md new file mode 100644 index 000000000..1c9c2854b --- /dev/null +++ b/data/en.wikipedia.org/wiki/RIKEN_Brain_Science_Institute-0.md @@ -0,0 +1,19 @@ +--- +title: "RIKEN Brain Science Institute" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/RIKEN_Brain_Science_Institute" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:03.181973+00:00" +instance: "kb-cron" +--- + +RIKEN Brain Science Institute (RIKEN-BSI) was established in 1997 as part of RIKEN, focusing on neuroscience research located in Wakō city, Saitama Prefecture in the greater Tokyo area, Japan. In 2018 RIKEN-BSI has been reorganized as RIKEN Center for Brain Science, a new center under RIKEN. Yasushi Miyashita became the first Director of RIKEN-CBS.The current director is Ryoichiro Kageyama (2021-). + + +== Overview of RIKEN-BSI == +Masao Ito, formerly a professor at the Faculty of Medicine of Tokyo University, joined RIKEN as the second director of the (former) International Frontier System and initiated the neuroscience research in RIKEN in 1989 after his retirement. It was first major move towards biological science in RIKEN, which had been dominated by physics and chemistry. In 1997, it was expanded to become BSI and Ito became the first director. Subsequently, it was led by the second director, Shun'ichi Amari and interim director Keiji Tanaka, and then currently by 1987 Nobel laureate Susumu Tonegawa (2009-). +Aiming at an interdisciplinary understanding of the brain, its research target ranges from molecular and cell biology to cognitive and computational neuroscience. + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/RIKEN_MDGRAPE-3-0.md b/data/en.wikipedia.org/wiki/RIKEN_MDGRAPE-3-0.md new file mode 100644 index 000000000..4e4fe5a5b --- /dev/null +++ b/data/en.wikipedia.org/wiki/RIKEN_MDGRAPE-3-0.md @@ -0,0 +1,29 @@ +--- +title: "RIKEN MDGRAPE-3" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/RIKEN_MDGRAPE-3" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:04.347577+00:00" +instance: "kb-cron" +--- + +RIKEN MDGRAPE-3 is an ultra-high performance petascale supercomputer system developed by the Riken research institute in Japan. It is a special purpose system built for molecular dynamics simulations, especially protein structure prediction. +MDGRAPE-3 consists of 201 units of 24 custom MDGRAPE-3 chips (4,824 total), plus additional dual-core Intel Xeon processors (codename "Dempsey") which serve as host machines. +In June 2006 Riken announced its completion, achieving the petaFLOPS level of floating point arithmetic performance. This was more than three times faster than the 2006 version of the IBM Blue Gene/L system, which then led the TOP500 list of supercomputers at 0.28 petaFLOPS. Because it's not a general-purpose machine capable of running the LINPACK benchmarks, MDGRAPE-3 does not qualify for the TOP500 list. + + +== See also == +Supercomputing in Japan +MDGRAPE-4 + + +== References == + + +== External links == +MD-GRAPE Project@IBM +High-Performance Molecular Simulation Team@Riken +Peta Computing Institute +Tetsu Narumi's MDGRAPE page Archived 2008-02-13 at the Wayback Machine +Molecular Dynamics Machine using MDGRAPE-2 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/RIKEN_Quantitative_Biology_Center-0.md b/data/en.wikipedia.org/wiki/RIKEN_Quantitative_Biology_Center-0.md new file mode 100644 index 000000000..ac15ae93d --- /dev/null +++ b/data/en.wikipedia.org/wiki/RIKEN_Quantitative_Biology_Center-0.md @@ -0,0 +1,37 @@ +--- +title: "RIKEN Quantitative Biology Center" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/RIKEN_Quantitative_Biology_Center" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:05.926030+00:00" +instance: "kb-cron" +--- + +The Quantitative Biology Center (QBiC) is a Strategic Research Center of the Japanese national research and development institute, Riken. In November 2014, they succeeded in making a translucent mouse in order to see its internal organs more clearly. + + +== Overview == +QBiC is a systems biology research center. The center is led by director Toshio Yanagida and is divided into three research cores. + +Cell Dynamics Research Core +Computational Biology Research Core +Cell Design Research Core + + +== Research Cores == + + +=== Cell Dynamics Research Core === +The Cell Dynamics Research Core houses the Laboratory for Cell Polarity Regulation, led by Yasushi Okada. Okada reported the first visualization of Mitochondrial Derived Vesicles (MDV) from mitochondrial protrusions using ultrafast super-resolution fluorescence imaging with spinning disk confocal microscope optics. This core also includes Shuichi Onami's Laboratory for Developmental Dynamics creator of the Biological Dynamics Markup Language (BDML). The Onami lab hosts the Systems Science of Biological Dynamics (SSBD) database. + + +=== Computational Biology Research Core === +The Computational Biology Research Core is a user of the K computer and developer of the MDGRAPE-4 supercomputer. + + +=== Cell Design Research Core === +The Cell Design Research Core houses the Laboratory for Synthetic Biology which reported the see-through mouse. This core is also notable for housing Yoshihiro Shimizu's Laboratory for Cell-Free Protein Synthesis, developer of the PURE cell free protein expression system. Yo Takana's Laboratory for Integrated Biodevice, which created a battery from the electric organ of a torpedo ray. + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_1-0.md b/data/en.wikipedia.org/wiki/Ranger_1-0.md new file mode 100644 index 000000000..b57b28cf8 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_1-0.md @@ -0,0 +1,57 @@ +--- +title: "Ranger 1" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Ranger_1" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:43.833832+00:00" +instance: "kb-cron" +--- + +Ranger 1 was a prototype spacecraft launched as part of the Ranger program of uncrewed space missions. Its primary mission was to test the performance of those functions and parts necessary for carrying out subsequent lunar and planetary missions; a secondary objective was to study the nature of particles and fields in the space environment. Due to a launch vehicle malfunction, the spacecraft could reach only Low Earth orbit, rather than the high Earth orbit that had been planned, and was only able to complete part of its mission. + + +== Spacecraft design == +The spacecraft was of the Ranger Block I design and consisted of a hexagonal base 1.5 meters (4 ft 11 in) across upon which was mounted a cone-shaped 4-meter (13 ft) high tower of aluminum struts and braces. Two solar panel wings measuring 5.2 meters (17 ft) from tip to tip extended from the base. A high-gain directional dish antenna was attached to the bottom of the base. Spacecraft experiments and other equipment were mounted on the base and tower. Instruments aboard the spacecraft included a Lyman-alpha telescope, a rubidium-vapor magnetometer, electrostatic analyzers, medium-energy range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber, cosmic dust detectors, and solar X-ray scintillation counters. There was no camera or midcourse correction engine on the Block I spacecraft. +The communications system included the high-gain antenna and an omnidirectional medium-gain antenna and two transmitters, one at 960.1 MHz with 0.25 watts power output and the other at 960.05 MHz with 3 watts power output. Power was to be furnished by 8680 solar cells on the two panels, a 57-kilogram (126 lb) silver-zinc battery, and smaller batteries on some of the experiments. Attitude control was provided by a solid-state timing controller, Sun and Earth sensors, and pitch and roll jets. The temperature was controlled passively by gold plating, white paint, and polished aluminum surfaces. + + +== Mission == +The Ranger 1 spacecraft was designed to go into an Earth parking orbit and then move into a 60,000-by-1,100,000-kilometre (37,000 by 684,000 mi) Earth orbit. The purpose of the mission was mainly as an engineering test to verify the functionality of the Ranger hardware. + + +=== Launch delays === +Delay of the 1st countdown +July 26: Trajectory information required by the Range Safety Officer was delayed. +July 27: A guidance system malfunction in the Atlas booster. +July 28: Engineers found that the guidance program to be fed into the Cape computer contained an error. +1st countdown. July 29. +83 minutes before launch: Power interruptions occurred, requiring momentary holds to permit all stations to check and recover. +28 minutes before launch: Commercial electrical power failed. Inadequate allowance had been made for changes in cable sag caused by variations in temperature on the new power poles recently installed at Cape Canaveral Air Force Station. +2nd countdown. July 30. Engineers discovered a leak in Ranger's attitude control gas system. +3rd countdown. July 31. A LOX tank pressure regulator seal developed a leak due to damage resulting from improper handling. +4th countdown. August 1. Ground controllers turned on a spacecraft command applying high voltage to the scientific experiments for calibration purposes. Immediately all stations reported a major spacecraft failure. An electrical malfunction had triggered multiple commands from the central clock timer, and Ranger 1 "turned on" as it had been programmed to do in orbit. The explosive squibs fired, solar panels extended inside the shroud, and all the experiments commenced to operate. Project engineers disengaged Ranger 1 from the Agena and hastily returned it to Hangar AE. Meantime, the launch was rescheduled for August 22, the next available opportunity. Subsequent tests and investigations determined the activating mechanism to have been a voltage discharge to the spacecraft frame; although engineers suspected one or two of the scientific instruments, they could not determine the precise source of the discharge with certainty. In the days that followed, they replaced and requalified the damaged parts and modified the circuitry to prevent a recurrence of this kind of failure. + + +=== Launch === +During the first half of 1961, Lockheed introduced the new Agena B stage which replaced the early test-model Agena A of 1959-60. Agena B was more powerful and had in-orbit restart capability. Its first flight with the launch of Midas 3 on July 24 was successful. Several frustrating delays in Ranger 1's launch occurred, including one episode where the spacecraft's timer inadvertently activated on the pad, causing the solar panels to be deployed inside the payload shroud. After removing Ranger 1 and repairing it, the launch was carried out at 6:04 AM EST on August 23. All went well up to orbital injection, but the planned Agena restart went awry when the engine shut down after only a few seconds, putting the probe in a 312x105 mile track. Subsequent investigation concluded that an electrical circuit in the Agena had overheated from exposure to the Sun. The unintended orbit made it difficult to operate Ranger 1's systems correctly, although ground controllers tried to work around it. The main problem they faced was with the solar panels; Ranger 1 would experience 90 minutes of darkness while passing around the nighttime side of the Earth. In addition, the antennas at NASA's various tracking stations had difficulty locking onto the probe due to its orbital plane. During this time, the computer system repeatedly fired the attitude control jets in a vain attempt to lock onto the Sun with the effect that only one day after launch, the probe ran out of attitude control gas. At this point, it could not be stabilized and the solar panels lost their lock on the Sun. Ranger 1 thus reverted to battery power and continued transmitting until the batteries ran down on August 27 and all signals from the probe ceased. It was not a total loss; the spacecraft systems had worked well and some data on cosmic rays and radiation was returned, however the low orbit precluded the use of the magnetometer. After four days and 111 orbits, Ranger 1 reentered and burned up over the Gulf of Mexico. + + +== Footnotes == + + +== See also == + +Ranger program +Timeline of Solar System exploration +List of artificial objects on the Moon + + +== References == +"National Space Science Data Center - Ranger 1". National Air and Space Administration. Retrieved 19 June 2012. +"LUNAR IMPACT: A History of Project Ranger - Part I. THE ORIGINS OF RANGER - TEST FLIGHTS AND DISAPPOINTMENTS - A LEARNING EXPERIENCE". NASA. 2006. Retrieved 2010-08-30. + + +== External links == +Space flight operations memorandum - Ranger 1 (Post-Flight Mission Analysis) +Lunar impact: A history of Project Ranger (PDF) 1977 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_2-0.md b/data/en.wikipedia.org/wiki/Ranger_2-0.md new file mode 100644 index 000000000..8563e9caa --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_2-0.md @@ -0,0 +1,41 @@ +--- +title: "Ranger 2" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Ranger_2" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:45.120838+00:00" +instance: "kb-cron" +--- + +Ranger 2 was a flight test of the Ranger spacecraft system of the NASA Ranger program designed for future lunar and interplanetary missions. Ranger 2 was designed to test various systems for future exploration and to conduct scientific observations of cosmic rays, magnetic fields, radiation, dust particles, and a possible hydrogen gas "tail" trailing the Earth. + + +== Spacecraft design == + +Ranger 2 was of the Ranger Block 1 design and was almost identical to Ranger 1. The spacecraft consisted of a hexagonal base 1.5 metres (4 ft 11 in) across, upon which was mounted a cone-shaped 4-meter-high (13-foot) tower of aluminum struts and braces. Two solar panel wings measuring 5.2 metres (17 ft) from tip to tip extended from the base. A high-gain directional dish antenna was attached to the bottom of the base. Spacecraft experiments and other equipment were mounted on the base and tower. Instruments aboard the spacecraft included a Lyman-alpha telescope, a rubidium-vapor magnetometer, electrostatic analyzers, medium-energy-range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber, cosmic dust detectors, and scintillation counters. +The communications system included the high-gain antenna and an omnidirectional medium-gain antenna and two transmitters at approximately 960 MHz, one with 0.25 W power output and the other with 3 W power output. Power was to be furnished by 8680 solar cells on the two panels, a 53.5 kilograms (118 lb) silver-zinc battery, and smaller batteries on some of the experiments. Attitude control was provided by a solid state timing controller, Sun and Earth sensors, gyroscopes, and pitch and roll jets. The temperature was controlled passively by gold plating, white paint, and polished aluminum surfaces. + + +== Mission == +Shortly after Ranger 1's unsuccessful mission, Atlas 117D and Agena 6002 were rolled out to LC-12 for the next attempt. Once again, getting the booster and spacecraft ready for flight proved a frustrating experience. On October 24, NASA received the news from the West Coast of the United States that a hydraulics failure had prevented Discoverer 33 from reaching orbit the previous day, which necessitated taking Agena 6002 down from the stack and giving it a thorough checkout. The stage was found to have the same problem as Discoverer 33's Agena, necessitating repair work. It took until mid-November before everything was finally ready. Liftoff took place at 3:12 AM EST on November 18. An improper autopilot signal resulted in Atlas BECO taking place 0.4 seconds early. Thus the sustainer phase of flight was initiated with below nominal velocity, but the vehicle reached orbit successfully since the guidance computer was programmed to not issue the SECO command until the proper velocity was achieved. A similar event occurred on the launch of SAMOS 4 a few days later and was caused by the switch malfunctioning from its location on the side of the extremely cold LOX tank. The switch was moved to the fuel tank on subsequent Atlas-Agena vehicles. +An inoperative roll gyro caused loss of Agena roll control from the moment of staging. The first burn was performed successfully but the control gas was exhausted trying to keep the vehicle stable so when it came time for restart, the engine shut down after only one second of operation due to ingestion of control gas. Unlike with Ranger 1, the Agena had not operated long enough to achieve any significant ISP and so the probe was left in an even lower orbit. Tracking antennas could not lock onto the probe or send it any commands, nor could the attitude control system stabilize it. Telemetry and instrument data were still received for a few hours, but eventually the orbit decayed too low and after only one day and 19 orbits, Ranger 2 reentered the atmosphere and burned up. As a result of the failure, Agena vehicles would get a version of the Atlas's Spin Motor Rotation Detection System to ensure proper gyroscope operation at launch. + + +== See also == + +Ranger program +Timeline of Solar System exploration +List of artificial objects on the Moon + + +== Footnotes == + + +== References == +"National Space Science Data Center - Ranger 2". National Air and Space Administration. Retrieved 19 June 2012. + + +== External links == +Space Flight Operations Memorandum - Ranger 2 (Post-flight Mission Analysis) +Lunar impact: A history of Project Ranger (PDF) 1977 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_3-0.md b/data/en.wikipedia.org/wiki/Ranger_3-0.md new file mode 100644 index 000000000..dec0275c4 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_3-0.md @@ -0,0 +1,23 @@ +--- +title: "Ranger 3" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Ranger_3" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:46.346472+00:00" +instance: "kb-cron" +--- + +Ranger 3 was a space exploration mission conducted by NASA to study the Moon. The Ranger 3 robotic spacecraft was launched January 26, 1962 as part of the Ranger program. Due to a series of malfunctions, the spacecraft missed the Moon by 22,000 miles (35,000 km) and entered a heliocentric orbit. +The Ranger 3 space probe was designed to transmit pictures of the lunar surface during a period of 10 minutes of flight prior to impacting on the Moon, to rough-land a seismometer capsule on the Moon, to collect gamma-ray data in flight, to study radar reflectivity of the lunar surface, and to continue testing of the Ranger program for development of lunar and interplanetary spacecraft. + +== Spacecraft design == +Ranger 3 was the first of the Block II Ranger designs. The basic vehicle was 3.1 m high and consisted of a lunar capsule covered with a balsa wood impact-limiter, 635 mm in diameter (25 inches), a mono-propellant mid-course motor, a retrorocket with a thrust of 5080 pounds force (22.6 kN), and a gold- and chrome-plated hexagonal base 1.5 m in diameter. A large high-gain dish antenna was attached to the base. Two wing-like solar panels (5.2 m across) were attached to the base and deployed early in the flight. Power was generated by 8680 solar cells contained in the solar panels which charged an 11.5 kg 1 kW·h capacity AgZn launching and backup battery. Spacecraft control was provided by a solid-state computer and sequencer and an earth-controlled command system. Attitude control was provided by Sun and Earth sensors, gyroscopes, and pitch and roll jets. The telemetry system aboard the spacecraft consisted of two 960 MHz transmitters, one at 3 W power output and the other at 50 mW power output, the high-gain antenna, and an omnidirectional antenna. White paint, gold and chrome plating, and a silvered plastic sheet encasing the retrorocket furnished thermal control. +During prelaunch preparations for Ranger 1, the spacecraft's timer had accidentally been started which led to the deployment of the solar panels inside the payload shroud. It was decided that ground testing of the onboard instruments would not be done on the Block II spacecraft because they had a functional midcourse correction engine and if a similar incident happened with them, the squibs and pyrotechnics used to deploy the solar panels could inadvertently ignite the propellants in the onboard engine, which could result in the explosion of the spacecraft on the pad and possibly take the entire launch vehicle with it. JPL officials announced that factory testing of the Ranger's systems was sufficient to root out any problems and any hardware which failed to pass the tests was not fit to fly. +The experimental apparatus included: (1) a vidicon television camera, which employed a scan mechanism that yielded one complete frame in 10 s; (2) a gamma-ray spectrometer mounted on a 1.8 m boom; (3) a radar altimeter; and (4) a seismometer to be rough-landed on the lunar surface. The seismometer (code-named "Tonto") was encased in the lunar capsule along with an amplifier, a 50 mW transmitter, voltage control, a turnstile antenna, and six silver-cadmium batteries capable of operating the lunar capsule transmitter for 30 days, all designed to land on the Moon at 130 to 160 km/h (80 to 100 mph). The radar altimeter would be used for reflectivity studies, but was also designed to initiate capsule separation and ignite the retrorocket. + +== Mission == + +This was the first American attempt to achieve impact on the lunar surface. The Block II Ranger spacecraft carried a TV camera that used an optical telescope that would allow imaging down to about 24 kilometers above the lunar surface during the descent. The main bus also carried a 42.6 kilogram instrument capsule that would separate from the bus at 21.4 kilometers altitude and then independently impact on the Moon. Protected by a balsa-wood outer casing, the capsule was designed to bounce several times on the lunar surface before coming to rest. The primary onboard instrument was a seismometer. +The mission was designed to boost towards the Moon by an Atlas/Agena, undergo one mid-course correction, and impact the lunar surface. At the appropriate altitude, the capsule was to separate and the retrorockets ignite to cushion the landing. A malfunction in the booster guidance system resulted in excessive spacecraft speed. +Reversed command signals caused the spacecraft to pitch in the wrong direction and the TM antenna to lose earth acquisition, and mid-course correction was not possible. Finally, a spurious signal during the terminal maneuver prevented transmission of useful images. Ranger 3 missed the Moon by approximately 36,800 km on January 28 and entered a heliocentric orbit. Some useful engineering data were obtained from the flight. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_3-1.md b/data/en.wikipedia.org/wiki/Ranger_3-1.md new file mode 100644 index 000000000..212d411b6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_3-1.md @@ -0,0 +1,37 @@ +--- +title: "Ranger 3" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Ranger_3" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:46.346472+00:00" +instance: "kb-cron" +--- + +=== Preparation for launch === +Preparation for Ranger 3 was complicated by developmental issues with the Agena B stage, which had failed to operate correctly on Rangers 1-2. Agena was primarily the domain of the U.S. Air Force, who intended to use it for military payloads, and NASA had originally assumed it would begin flying in late 1960 or early 1961 by which time any developmental issues with the stage could be weeded out. However, Agena B ended up taking longer to put into service than originally anticipated and its performance also turned out to be somewhat less than expected, which forced some of the planned experiments on the Block II Rangers to be cancelled. +While the Thor-Agena B had begun flying in October 1960, the Atlas-Agena B did not make its maiden voyage until July 1961, meaning that Ranger 1 was only the second time this launch vehicle combination had been flown. This delay was explained by the fact that Air Force programs such as MIDAS were taking much longer to develop than Ranger. In addition, as 1961 ended, Agena Bs had malfunctioned no less than seven times (the two Ranger launches and five Thor-Agena launches). +Major General Osmond J. Ritland, Commander of the Air Force Space Systems Division in Inglewood, California, promised NASA that all problems with Agena would be corrected and, because they also affected DoD programs, the issue was being taken "quite seriously". Among other changes made would be a thorough review of all Lockheed field operating equipment and procedures. In addition, an effort would be made to ensure that checkout procedures on U.S. Air Force and NASA Agenas were identical and any differences in them eliminated. + +In mid-December 1961, Atlas 121D and Agena 6003 arrived at Cape Canaveral and were erected on LC-12. On January 18, 1962, Ranger 3 was stacked atop the booster, but the following day attempted fueling of the Atlas went awry when a tear was found in the intermediate bulkhead separating the LOX and RP-1 tanks. This would mean that the launch vehicle would have to be taken down from the pad for repairs, delaying the launch an entire month. However, Air Force and Convair officials instead suggested the novel solution of doing the repairs right there on LC-12. The Atlas's sustainer engine was removed and lowered into the flame deflector pit and wooden scaffolding installed so that technicians could go up into the RP-1 tank, remove the damaged intermediate bulkhead, and replace it. By January 26, repairs were completed. + +=== Equipment malfunctions and trajectory errors === + +Liftoff took place at 3:30 PM EST on January 26, an hour and 15 minutes before the launch window closed, after which Ranger 3 could not have been launched for another month. +At T+49 seconds into launch, the pulse beacon on the Atlas guidance system ceased operating, which prevented the transmission of any steering or cutoff directions for the remainder of the launch. Backup commands from the missile programmer ensured proper SECO and VECO commands but the lack of steering discreets resulted in an improper flight trajectory with excessive velocity. +Even worse, equipment at a Florida tracking station malfunctioned and picked up Ranger 3's orbital parameters 5 minutes late. Meanwhile, the Agena restarted and sent the probe out of Earth orbit, but another error in its guidance program resulted in yet another trajectory error. As a consequence, the spacecraft reached the Moon 14 hours early and on January 28 missed striking the Moon by 36,793 kilometers (22,862 miles). +The trajectory errors made impact with the Moon impossible, but Ranger 3 could still have been used for deep-space studies. So the flight controllers issued commands to unfurl the camera boom, and on January 28 an amended computer program was uploaded. However, midway through the upload, the probe's signal strength began to weaken and the onboard computer system failed completely. Without a functioning computer, the spacecraft was not able keep its high-gain antenna aimed at the Earth, which impeded communication with controllers on the ground. + +=== Mission failure, propellant exhaustion, and cancellation === +The TV camera did transmit images, but since the antenna was now pointed away from Earth, the received images were extremely weak and noisy. It was possible to see the reference crosses on the camera lens, illuminated by reflected sunlight from the probe's chassis, but the Moon was not visible. +With the computer dead, Ranger 3 became completely unresponsive to any ground commands and the Earth and Sun sensors were rendered useless. The gyroscopes continued to maneuver the probe and ground controllers momentarily reacquired a lock on the antenna, but without stable attitude control, they could not hold it steady. As they were unaware of the computer failure, they continued sending commands to Ranger 3 in vain. Sporadic tracking of the probe continued until January 31 when the attitude control thrusters exhausted their propellant supply, at which point the mission was officially terminated. + +== See also == + +Ranger program +Timeline of Solar System exploration + +== References == + +== External links == +Lunar impact: A history of Project Ranger (PDF) 1977 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_4-0.md b/data/en.wikipedia.org/wiki/Ranger_4-0.md new file mode 100644 index 000000000..d3049c00f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_4-0.md @@ -0,0 +1,46 @@ +--- +title: "Ranger 4" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Ranger_4" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:47.571647+00:00" +instance: "kb-cron" +--- + +Ranger 4 was a spacecraft of the Ranger program, launched in 1962. It was designed to transmit pictures of the lunar surface to Earth stations during a period of 10 minutes of flight prior to crashing upon the Moon, to rough-land a seismometer capsule on the Moon, to collect gamma-ray data in flight, to study radar reflectivity of the lunar surface, and to continue testing of the Ranger program for development of lunar and interplanetary spacecraft. +An onboard computer failure caused failure of the deployment of the solar panels and navigation systems; as a result the spacecraft crashed on the far side of the Moon without returning any scientific data. It was the first spacecraft of the United States to reach another celestial body and the first of any nation to reach the surface of the far side of the Moon. + + +== Spacecraft design == + +Ranger 4 was a Block II Ranger spacecraft virtually identical to Ranger 3. The basic vehicle was 331 kg (730 lb), 3.1 m (10 ft) high and consisted of a lunar capsule covered with a balsawood impact-limiter, 0.65 m (26 in) in diameter, a mono-propellant mid-course motor, a 22.6 kN (5,080 lbf) thrust retrorocket, and a gold- and chrome-plated hexagonal base 1.5 m (4 ft 11 in) in diameter. A large high-gain dish antenna was attached to the base. Two wing-like solar panels (5.2 m (17 ft) across) were attached to the base and deployed early in the flight. +Power was generated by 8,680 solar cells contained in the solar panels which charged an 11.5 kg (25 lb) 1 kWh capacity AgZn launching and backup battery. Spacecraft control was provided by a solid-state computer and sequencer and an Earth-controlled command system. Attitude control was provided by Sun and Earth sensors, gyroscopes, and pitch and roll jets. The telemetry system aboard the spacecraft, consisting of two 960 MHz transmitters, one at 3 W power output and the other at 50 mW power output, the high-gain antenna, and an omnidirectional antenna. White paint, gold and chrome plating, and a silvered plastic sheet encasing the retrorocket furnished thermal control. +Because heat sterilization was suspected to have caused the malfunction of Ranger 3's computer, this procedure was dropped on Ranger 4. The seismometer capsule was also painted with a sawtooth pattern for better thermal protection. +The experimental apparatus included: (1) a vidicon television camera, which employed a scan mechanism that yielded one complete frame in ten seconds; 2) a gamma-ray spectrometer mounted on a 1.8 m (5 ft 11 in) boom; (3) a radar altimeter; and (4) a seismometer to be rough-landed on the lunar surface. The seismometer was encased in the lunar capsule along with an amplifier, a 50-milliwatt transmitter, voltage control, a turnstile antenna, and six silver-cadmium batteries capable of operating the lunar capsule transmitter for 30 days, all designed to land on the Moon at 130 to 160 km/h (80 to 100 mph). The radar altimeter would be used for reflectivity studies, but was also designed to initiate capsule separation and ignite the retro-rocket. + + +== Mission == +Atlas 133D and Agena 6004 arrived at Cape Canaveral in March and began preflight checkouts. Unlike with previous Ranger launches, no serious difficulties were encountered in readying the launch vehicle for flight and the probe also passed all systems tests with ease. On April 20, Ranger 4 was stacked atop the booster and liftoff took place at 3:50 pm EST on April 23. Launch proceeded perfectly this time and there were no anomalies with either the Atlas or the Agena, which performed its second burn to send Ranger 4 on a translunar trajectory. +After separation from the Agena, it was apparent that something was seriously amiss when tracking stations picked up Ranger 4's radio transmitter, but there was no telemetry data being returned or any response when commands were sent to the computer. Without telemetry, it could not be confirmed that the probe's solar panels had unfolded, but the fluctuating radio transponder indicated that Ranger 4 was tumbling and that the solar panels and high-gain antenna were not deployed either. +The Atlas and Agena had both performed perfectly, in fact so well that Ranger 4 would not even need a midcourse correction burn to impact the Moon. However, this was all futile if the spacecraft was inoperative. Ground controllers sent commands to the probe to unfurl the solar panels and high-gain antenna and manually use the attitude control system to stop the rolling motion it was in, but the probe was unresponsive. The Spacecraft Data Analysis Team at JPL concluded that the main timer in Ranger 4's computer had stopped, which disabled the telemetry system, preprogrammed events such as solar panel deployment, and also made the probe completely unresponsive to manual commands. Even though lunar impact would occur as planned, the mission was for all intents and purposes a failure. Making it a more bitter pill to swallow was the nearly-flawless launch vehicle performance. The booster problems that affected Rangers 1-3 had been resolved, only for the probe itself to completely fail, as unlike the previous missions, Ranger 4 did not return any useful data. Finding the cause of the timer malfunction could also be difficult since it had occurred during the coasting phase prior to trans-lunar injection when Ranger 4 was passing between tracking stations in the Caribbean and South Africa. +Without solar power, Ranger 4's batteries ran down on the morning of April 26 and the radio transponder ceased operating. The tiny transmitter in the seismometer capsule continued sending out a 50-milliwatt signal. According to NASA, Ranger 4 impacted the far side of the Moon (229.3 degrees E, 15.5 degrees S) at 9,600 km/h (5,970 mph) at 12:49:53 UT on April 26, 1962, after 64 hours of flight. However, the coordinates were ″guesstimated", and while the impact crater was presumably imaged by the later Lunar Reconnaissance Orbiter, the exact crater has not been identified. +NASA officials tried to put a positive spin on the mission, noting that it was the first time an American spacecraft had reached the surface of the Moon and that the probe was "far more sophisticated" than the Soviet Luna 2 space probe in 1959, which had been little more than a pressurized sphere designed to deposit pennants on the surface at impact. The excellent performance of the Atlas-Agena booster had also raised morale. +This spacecraft, similar in design to Ranger 3, was the first American spacecraft to reach another celestial body. It was also the first spacecraft to impact the far side of the Moon. Although the spacecraft did not achieve its primary objective, the Atlas-Agena-Ranger combination performed without fault for the first time. + + +== See also == + +Ranger program +Timeline of Solar System exploration +List of artificial objects on the Moon +List of missions to the Moon + + +== References == + + +== External links == +Lunar impact: A history of Project Ranger (PDF) 1977 +Reuters.com, Planned lunar missions +Reuters.com, Chronology – Five key dates in the race to the Moon \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_5-0.md b/data/en.wikipedia.org/wiki/Ranger_5-0.md new file mode 100644 index 000000000..cb1253ed1 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_5-0.md @@ -0,0 +1,20 @@ +--- +title: "Ranger 5" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Ranger_5" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:48.824670+00:00" +instance: "kb-cron" +--- + +Ranger 5 was a spacecraft of the Ranger program designed to transmit pictures of the lunar surface to Earth stations during a period of 10 minutes of flight prior to impacting on the Moon, to rough-land a seismometer capsule on the Moon, to collect gamma-ray data in flight, to study radar reflectivity of the lunar surface, and to continue testing of the Ranger program for development of lunar and interplanetary spacecraft. Due to an unknown malfunction, the spacecraft ran out of power and ceased operation. It passed within 725 km of the Moon. + +== Spacecraft design == +Ranger 5 was a Block II Ranger spacecraft similar to Ranger 3 and Ranger 4. The basic vehicle was 3.1 m high and consisted of a lunar capsule covered with a balsawood impact-limiter, 65 cm in diameter, a mono-propellant mid-course motor, a retrorocket with a thrust of 5,080 lbf (22.6 kN), and a gold and chrome plated hexagonal base 1.5 m in diameter. A large high-gain dish antenna was attached to the base. Two wing-like solar panels (5.2 m across) were attached to the base and deployed early in the flight. Power was generated by 8680 solar cells contained in the solar panels which charged an 11.5 kg 1 kWh capacity AgZn launching and backup battery. Spacecraft control was provided by a solid-state digital computer and sequencer and an Earth-controlled command system. Attitude control was provided by six Sun and one Earth sensor, gyroscopes, and pitch and roll cold nitrogen gas jets. The telemetry system aboard the spacecraft consisted of two 960 MHz transmitters, one at 3 W power output and the other at 50 mW power output, the high-gain antenna, and an omnidirectional antenna. White paint, gold and chrome plating, and a silvered plastic sheet encasing the retrorocket furnished thermal control. +The experimental apparatus included: (1) a vidicon television camera, which employed a scan mechanism that yielded one complete frame in 10 s; (2) a gamma-ray spectrometer in a 300 mm sphere mounted on a 1.8 m boom; (3) a radar altimeter; and (4) a seismometer to be rough-landed on the lunar surface. The seismometer was encased in the lunar capsule along with an amplifier, a 50 mW transmitter, voltage control, a turnstile antenna, and six silver-cadmium batteries capable of operating the lunar capsule transmitter for 30 days, all designed to land on the Moon at 130 to 160 km/h (81 to 99 mph). The instrument package floated in a layer of freon within the balsawood sphere. The radar altimeter would be used for reflectivity studies, but was also designed to initiate capsule separation and ignite the retro-rocket. + +== Mission == + +Ranger 5 was scheduled for launch in June 1962, but NASA instead decided to fly the Mariner Venus probes (derived from Block I Ranger) first which gave more time to work out problems with the spacecraft. After Mariner 1 ended its mission in the Atlantic Ocean instead of interplanetary space, the agency started coming under increased scrutiny from Congress due to its apparent inability to have any kind of success with planetary probes. Republican Congressman James Fulton confronted NASA Director of the Office of Programs J.J. Wyatt, noting that Mariner 1 had cost U.S. taxpayers $14 million and that there was no excuse at this point for failures every launch. As July 1962 ended, there had been 12 planetary probe attempts going back to 1958 and only two (Pioneer 4 and Pioneer 5) accomplished all of their mission goals. It might have been small consolation that Soviet planetary probe efforts during this time were little more successful, but all of their failures were kept secret, so the Soviets did not have to answer to their public about the waste of tax money on failed space missions. +The successful launch of Mariner 2 on August 27 momentarily blunted criticism of NASA and Jet Propulsion Laboratory and also seemed to verify the soundness of the Ranger design. Meanwhile, JPL engineers were still trying to figure out what had caused the computer failure on Ranger 4, which had occurred during a period when the probe was out of range of ground tracking. The malfunction was especially puzzling because the probe had been given very thorough ground testing without any anomalies occurring. Examination of telemetry records seemed to suggest that the failure had occurred during separation of Ranger 4 from the Agena, at the point where the electrical interface between the two was disconnected and Ranger 4 would have switched to internal power. The behavior of the probe indicated a transformer or inverter malfunction, probably a short circuit caused by loose metal coatings contacting the pins on the power umbilical attaching the probe to the Agena. Modifications to Ranger 5 included a backup timer to ensure continued operation of the telemetry system if the main computer failed, an additional nitrogen bottle to the attitude control system to reduce gas pressure, and an additional pyrotechnic igniter for the midcourse correction engine. Most importantly, extra diodes and fuses were added to the electrical lines to prevent another short from occurring. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_5-1.md b/data/en.wikipedia.org/wiki/Ranger_5-1.md new file mode 100644 index 000000000..383200f8e --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_5-1.md @@ -0,0 +1,28 @@ +--- +title: "Ranger 5" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Ranger_5" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:48.824670+00:00" +instance: "kb-cron" +--- + +Ranger 5 was heat-sterilized like Rangers 3-4 had been, so as to prevent unintended contamination of the Moon with Earth microbes. Rolf Halstrup, who was in charge of the sterilization program, had vocally objected to this procedure as he was convinced that subjecting the probes to a heat dosage was damaging the sensitive electronics in them. He convinced JPL in Pasadena management that sterilization of Ranger 4 had "very likely" damaged the main computer sequencer and timer and that the procedure needed to be stopped to ensure reliability of the spacecraft. Management agreed to stop sterilizing Ranger probes, but only on Ranger 8 and up, as Rangers 6-7 had already been sterilized. +On August 20, Ranger 5 began the long cross-country trip from state of California to Florida and arrived there the day of Mariner 2's launch. Atlas 215D and Agena 6005 arrived later that week and prelaunch checkouts were started. Initial preparations focused on the launch vehicle itself, which was causing almost as many problems as the Ranger probes themselves. The Atlas-Agena combination malfunctioned four out of the six times that NASA had launched it and every booster that was delivered to Cape Canaveral required modifications or repair work before it could fly. Moreover, in the year between Ranger 1 and Mariner 2, there had been no improvement whatsoever in the quality control of the Atlas-Agenas. Since Ranger launches had been delayed before by booster problems, technicians rushed to make sure nothing of the sort would delay Ranger 5's mission. +Tracking of Mariner 2 was an ongoing job during this time and since NASA's deep space tracking networks could not handle both probes at once, it was decided to switch attention to Ranger 5 for its short mission. +After two launch attempts were aborted, one due to an electrical short in the probe and the other due to weather concerns, the go to fly was given for October 18. Liftoff took place at 12:59 PM EST and the Atlas soon vanished into an overcast gray sky. A malfunction of the guidance system rate beacon at T+93 seconds resulted in noisy track rate data, but, unlike Ranger 3, discrete commands were received and issued by the guidance system properly. The Agena reached orbit successfully and began the burn to place Ranger 5 on a translunar trajectory. +Soon, however, high temperatures were detected in the computer system, and shortly afterwards, power generation from the solar panels ceased. The gamma ray detector was turned on, but the computer did not issue the command to align the spacecraft with Earth. Then the telemetry receivers at the tracking stations in Australia and South Africa malfunctioned, returning garbled data. It was obvious that an electrical short had disabled the solar panels, which meant that Ranger 5 now had only a few hours before it would run out of battery power. JPL technicians thought that they could still partially salvage the mission by firing the midcourse correction engine to ensure impact with the Moon, but they had to do it quickly before power ran out. Ground controllers sent commands to unfurl the high-gain antenna and align the probe for the midcourse burn, but during this time more electrical shorts apparently occurred because there was a momentary dropout from the telemetry transmitter. The midcourse engine was fired, but Ranger 5 exhausted its batteries halfway through the burn. The radio transponder and telemetry signals ceased, followed by uncontrolled tumbling of the probe. Ranger 5 passed 450 miles from the lunar surface en route to a permanent orbit around the Sun. Signals were still received from the tiny seismometer capsule until fading as the probe's distance from Earth became too great. +Mission controllers tracked it to a distance of 1.3 million kilometres (810,000 mi). +This was the third attempt to impact the lunar surface with a Block II Ranger spacecraft. On this mission, just 15 minutes after normal operation, a malfunction led to the transfer of power from solar to battery power. Normal operation never resumed; battery power was depleted after 8 hours, and all spacecraft systems died. The first midcourse correction was never implemented, and Ranger 5 passed the Moon at a range of 724 kilometers on October 21 and entered heliocentric orbit. It was tracked to a distance of 1,271,381 kilometers. Before loss of signal, the spacecraft sent back about 4 hours of data from the gamma-ray experiment. + +== See also == + +Ranger program +Timeline of Solar System exploration +List of artificial objects on the Moon + +== References == + +== External links == +Lunar impact: A history of Project Ranger (PDF) 1977 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_6-0.md b/data/en.wikipedia.org/wiki/Ranger_6-0.md new file mode 100644 index 000000000..7e001a32c --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_6-0.md @@ -0,0 +1,25 @@ +--- +title: "Ranger 6" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Ranger_6" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:50.123122+00:00" +instance: "kb-cron" +--- + +Ranger 6 was a lunar probe in the NASA Ranger program, a series of robotic spacecraft of the early and mid-1960s to obtain close-up images of the Moon's surface. It was launched on January 30, 1964 and was designed to transmit high-resolution photographs of the lunar terrain during the final minutes of flight until impacting the surface. The spacecraft carried six television vidicon cameras—two wide-angle (channel F, cameras A and B) and four narrow-angle (channel P)—to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality television pictures. No other experiments were carried on the spacecraft. Due to a failure of the camera system, no images were returned. + +== Spacecraft design == + +Rangers 6, 7, 8, and 9 were called Block 3 versions of the Ranger spacecraft. The spacecraft consisted of a hexagonal aluminum frame base 1.5 m across on which was mounted the propulsion and power units, topped by a truncated conical tower that held the TV cameras. Two solar panel wings, each 739 mm wide by 1537 mm long, extended from opposite edges of the base with a full span of 4.6 m, and a pointable high-gain dish antenna was hinge mounted at one of the corners of the base away from the solar panels. A cylindrical quasi omnidirectional antenna was seated on top of the conical tower. The overall height of the spacecraft was 3.6 m. +Propulsion for the mid-course trajectory correction was provided by a 224 N thrust monopropellant hydrazine engine with four jet-vane vector control. Orientation and attitude control about three axes were enabled by twelve nitrogen gas jets coupled to a system of three gyros, four primary Sun sensors, two secondary Sun sensors, and an Earth sensor. Power was supplied by 9,792 silicon solar cells contained in the two solar panels, giving a total array area of 2.3 square meters and producing 200 W. Two 1200 watt-hour AgZnO batteries rated at 26.5 V with a capacity for 9 hours of operation provided power to each of the separate communication/TV camera chains. Two 1000 watt-hour AgZnO batteries stored power for spacecraft operations. +Communications were through the quasi omnidirectional low-gain antenna and the parabolic high-gain antenna. Transmitters aboard the spacecraft included a 60 W TV channel F at 959.52 MHz, a 60 W TV channel P at 960.05 MHz, and a 3 W transponder channel 8 at 960.58 MHz. The telecommunications equipment converted the composite video signal from the camera transmitters into an RF signal for subsequent transmission through the spacecraft high-gain antenna. Sufficient video bandwidth was provided to allow for rapid framing sequences of both narrow- and wide-angle television pictures. + +== Mission profile == + +The Cuban Missile Crisis had momentarily diverted attention from the failure of Ranger 5, but that mission forced a wholesale review of the entire Ranger program. Numerous theories were put forward about the cause of the failures, including poor management at JPL, overly-ambitious spacecraft designs that were unworkable and unreliable with contemporary technology, and some lesser reasons such as heat sterilization of the probes. +NASA established a Ranger Board of Inquiry on October 29, 1962, headed by Albert J. Kelley, with the mission of establishing by November 30 the reasons for the continued program failures. The board's findings included the verdict that the Ranger design was "more complicated than necessary" for a lunar mission and also required a very high degree of engineering and workmanship, neither of which were being delivered. They also concluded that heat sterilization was damaging to the delicate spacecraft systems and should be abandoned at once. They also found that JPL's handling of the program was poor, the spacecraft lacked redundant systems in the event of a malfunction, NASA's deep-space tracking network crews were not trained adequately and had deficiencies in their equipment, and finally, the Atlas-Agena booster's reliability was poor, having malfunctioned on eight Air Force and NASA launches as November 1962 ended. If the Thor-Agena was also counted in, there had been a total of nine times that an Agena B stage had malfunctioned in flight. +The board's recommendations included improving the management of projects, abandoning heat sterilization and testing of components designed for future planetary missions on Ranger, outsourcing assembly of the probes to a subcontractor, and excluding JPL from involvement in procurement and launching of the Atlas-Agena. Moreover, it suggested that NASA needed to improve their prelaunch testing and preparation of launch vehicles. +The Block III spacecraft would be stripped down to a minimum of instrumentation with the eight scientific instruments on Rangers 3-5 removed so that more space could be devoted to redundant systems hardware. This caused some protests from the scientific community that the gamma-ray and other measurements were far more valuable than simply returning photography of the Moon. Jet Propulsion Laboratory began more thorough testing of Ranger components and the second review board was put to work evaluating the reliability of the Atlas-Agena. +The booster problems would prove a particularly vexing one to solve because the U.S. Air Force, not NASA, was in charge of Atlas-Agena. Although NASA had hoped to launch planetary probes on Centaur, which was entirely under their control, that program was delayed by serious technical issues and would not be flight-ready for a long time. Having to share the booster with the U.S. Air Force and its Department of Defense missions on the West Coast created repeated mixups, delays, and technical problems. Therefore, it was recommended that NASA be given complete oversight in the procurement and launch of Atlas-Agena without the Air Force's involvement. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_6-1.md b/data/en.wikipedia.org/wiki/Ranger_6-1.md new file mode 100644 index 000000000..96ae4a986 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_6-1.md @@ -0,0 +1,16 @@ +--- +title: "Ranger 6" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Ranger_6" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:50.123122+00:00" +instance: "kb-cron" +--- + +One of the important parts of the Ranger program was monitoring all Atlas and Thor-Agena launches to check for failures that could directly affect it. This job had been assigned to the Marshall Space Flight Center in Huntsville, Alabama, but was instead moved to the Lewis Research Center (LRC) in Cleveland, Ohio. LRC sent additional personnel to the Convair assembly plant in San Diego to monitor the construction of Atlas vehicles. +The review board focused on the malfunctions plaguing Atlas-Agena, in particular, the General Electric guidance system, both the Mod III-G variant used on East Coast Atlas Agenas and the Mod II-A used on West Coast vehicles, which had malfunctioned repeatedly. They recommended putting forward more detailed and stringent requirements for testing Atlas vehicles and making sure the guidance package could withstand in-flight vibration levels along with improved fabrication of wiring harnesses. Also, it was recommended that Convair establish one standardized booster configuration for all U.S. Air Force and NASA launches instead of custom modifications for each mission, replacing hardware with known design flaws with better substitutes, and improved testing of everything. Since the Air Force was in charge of Atlas-Agena, it followed that all these changes required their approval. +Finally, NASA for the first time would be given complete oversight of all its space launches. Air Force involvement in procuring, preparing, and flying launch vehicles, as well as drafting postflight mission reports for NASA missions, was to end, a step that would greatly streamline and improve program efficiency. +Problems continued, this time with getting the TV cameras for Ranger 6 in working order. The camera tubes, supplied by Radio Corporation of America, were of variable quality and it took some time to find one that matched JPL's standards. +During testing of Atlas guidance systems at General Electric, it was found that gold coating on diodes was flaking off and causing electrical shorts. Even worse, Ranger 6 had hundreds of the same diodes. This problem had easily eluded testing; moreover, ground tests could not simulate a "zero gravity" environment in space where the gold flakes would float around and form a short between the legs of the diode. In the end, there was no choice except to replace every one of the several hundred diodes inside Ranger 6's circuitry. +In April 1963, the United States Congress also decided to cut funding to the Ranger program by nearly 50% on the grounds that "no success had been achieved with any of the missions to date". This meant that plans for Ranger probes up to 13 were cancelled. Only Rangers 6-9 would be flown and they would carry little more than a TV camera. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_6-2.md b/data/en.wikipedia.org/wiki/Ranger_6-2.md new file mode 100644 index 000000000..135ff82c8 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_6-2.md @@ -0,0 +1,27 @@ +--- +title: "Ranger 6" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Ranger_6" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:50.123122+00:00" +instance: "kb-cron" +--- + +One of the Ranger program's goals was looking for potential landing sites for crewed lunar missions. At this point, it was not clear exactly what the Moon's surface was like and widespread fears existed of there being bottomless quicksand that would swallow up spacecraft and astronauts. Since the basic design of the Apollo lunar module had already been finalized by 1963, landing on the Moon would only "confirm or deny that design". JPL decided to go for an impact point near the lunar equator, in the Sea of Tranquility, partially because it was considered a prime Apollo landing spot, and also because the target had to match lighting conditions during the time of launch in January–February. +Ranger 6 and its launch vehicle (Atlas 199D and Agena 6008) arrived at Cape Canaveral in mid-December and, with the nation still mourning President Kennedy's assassination the previous month, began preflight tests. +Liftoff took place at 10:49 AM EST on January 30, 1964. The Atlas lifted smoothly into an overcast sky and disappeared from view. All went well during the boost phase and the launch vehicle's performance was excellent, indicating the hard-fought effort to improve booster reliability. +Shortly after Atlas BECO and staging, an ominous development occurred when telemetry indicated that the telemetry for the TV camera on Ranger 6 had turned itself on and then back off again 67 seconds later. Telemetry data showed everything else appears to function normally and tensions at JPL eased. The Agena placed the probe into a parking orbit and then fired for translunar injection 25 minutes after launch. After separation of Ranger 6, the solar panels and high-gain antenna were extended and all appeared normal. The launch vehicle had placed the probe on an accurate enough flight path that only a short midcourse correction burn would be required. However, the activation of the TV camera telemetry during launch remained a cause for concern. JPL technicians wanted to turn the camera on to verify its operability, however, they were running the risk of not being able to turn it off again if an electrical short had indeed occurred somewhere. Since the camera had its own batteries and did not use the probe's main power bus, they would be depleted before it could get to the Moon and eliminate any chance of returning pictures. They decided that it was not worth compromising the mission and the camera would not be touched until descent to the Moon began. +Early on the morning of January 31, the command was sent to fire the midcourse correction engine, which performed flawlessly and set the probe on an impact course with the Sea of Tranquility. On February 2, JPL technicians prepared for the final phase of the mission. Ranger 6 began its descent and trajectory calculations determined that impact would occur close to the intended area. With the probe's angle suitable for taking images, the order was given to turn on the camera with 13 minutes and 10 seconds until impact. After an initial warm-up phase, the command to power them on was sent. However, no imagery or any sign of camera operation appeared. Two more commands were sent to turn on the camera, but still, nothing happened even though all other systems continued to operate normally. At 01:24 AM, impact with the Moon occurred and telemetry transmission from Ranger 6 ceased. The mission was over and for the 12th time in a row, a U.S. attempt to send a probe to the Moon had malfunctioned. Even worse, it had occurred one week before NASA officials were planning to announce to Congress their projected US$5.3 billion budget for FY 1965, a good deal of it related to crewed and uncrewed lunar missions. NASA attempted to put a positive spin on the mission by noting that, aside from the cameras, Ranger 6 and its Atlas-Agena booster had both functioned "extremely well". A review board determined the most likely cause of failure was due to an arc-over in the TV power system when it inadvertently turned on for 67 seconds approximately 2 minutes after launch during the period of booster-engine separation. + +== See also == + +Ranger program +Timeline of Solar System exploration +List of artificial objects on the Moon +List of missions to the Moon + +== References == + +== External links == +Lunar impact: A history of Project Ranger (PDF) 1977 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_7-0.md b/data/en.wikipedia.org/wiki/Ranger_7-0.md new file mode 100644 index 000000000..fff4344b7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_7-0.md @@ -0,0 +1,18 @@ +--- +title: "Ranger 7" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Ranger_7" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:51.327735+00:00" +instance: "kb-cron" +--- + +Ranger 7 was the first NASA space probe to successfully transmit close-up images of the lunar surface back to Earth. It was also the first completely successful flight of the Ranger program. Launched on July 28, 1964, Ranger 7 was designed to achieve a lunar-impact trajectory and to transmit high-resolution photographs of the lunar surface during the final minutes of flight up to impact. +The spacecraft carried six television vidicon cameras—two wide-angle (channel F, cameras A and B) and four narrow-angle (channel P)—to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality video pictures. Ranger 7 transmitted over 4,300 photographs during the final 17 minutes of its flight. After 68.6 hours of flight, the spacecraft impacted between Mare Nubium and Oceanus Procellarum. This landing site was later named Mare Cognitum. The velocity at impact was 2.61 kilometers per second (1.62 mi/s), and the performance of the spacecraft exceeded hopes. No other experiments were carried on the spacecraft. + +== Aftermath of Ranger 6 and preparation for Ranger 7 == + +Although NASA had attempted to put a positive spin on Ranger 6 on the grounds that everything except the camera system had worked well, William J. Coughlin, editor of the publication Missiles and Rockets, called it a "one hundred percent failure" and JPL's record thus far was "a disgrace". The mission had not been a complete failure, but Coughlin was not alone in his opinion that Jet Propulsion Laboratory in Pasadena, California, a nonprofit laboratory and extension of the California Institute of Technology (Caltech), was a "soft" academic environment without the drive or ambition needed to make the missions succeed. He considered Ranger a "loser" and, for a while, anyone at NASA involved in the Ranger program tried to conceal it. It was also being said that sending probes up for the sole purpose of returning images was pointless and accomplished nothing that Apollo could not also achieve. +Shortly after Ranger 6's mission concluded a review board was convened to resolve the cause of the TV camera failure. This was determined quickly; the inadvertent activation of the camera telemetry system during ascent had been caused by an electrical short that crippled the power supply for the cameras. But why it had happened was as yet a mystery, especially as telemetry data sent back from the probe could only provide a limited amount of information. On February 14, 1964, JPL released a report noting that an internal command switch could have activated prematurely or that arcing had occurred in the umbilical connector on the payload fairing. However, there was no evidence of the latter happening or any obvious way that it could occur and several modifications were proposed to the camera system and/or the payload fairing. +The NASA review board found that Ranger 6's systems were not as redundant as Jet Propulsion Laboratory had claimed, that prelaunch testing was inadequate, and there had been instances of the cameras turning themselves on at the RCA plant in New Jersey. If the cameras had to be completely redesigned from scratch, the next Ranger mission could be delayed almost a full year. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_7-1.md b/data/en.wikipedia.org/wiki/Ranger_7-1.md new file mode 100644 index 000000000..e2d0c5d44 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_7-1.md @@ -0,0 +1,25 @@ +--- +title: "Ranger 7" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Ranger_7" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:51.327735+00:00" +instance: "kb-cron" +--- + +The full report as submitted to Congress came under criticism from several people at NASA, noting that, although the cameras lacked redundancy, any one of dozens of failure modes in the booster or spacecraft could also result in failure to return any TV images. In regards to the lack of adequate prelaunch testing, they brought up the incident in 1961 with Ranger 1 deploying its solar panels during a ground test and that ground tests with full 60 Watt power had been discontinued on the Block II probes for fear of accidentally igniting the midcourse correction engine on the pad and destroying the entire launch vehicle in the process. +RCA also promised to look into workmanship standards at their main plant in Hightstown, New Jersey, when examination of a sealed Ranger module discovered a plastic bag with screws and washers inside. Although there was suspicion that this had been done by a disgruntled employee, it was far more probable that someone had done it by accident. +Since no obvious reason for the malfunction could be found in the cameras themselves, investigation next shifted to the electrical umbilical on the payload fairing. This umbilical connector would normally be attached on the ground to permit testing of the Ranger's subsystems and only a thin hinged door covered it during launch. One of the pins on the connector was "hot" and could easily be bridged, transferring a voltage to the adjacent pins and activating the TV camera system during launch. As for the cause of it, one possibility was electrostatic discharge, the other was a shock wave of some sort. +Alexander Bratenahl, a physicist at JPL's Space Sciences Division, suggested that the electrical short was caused by venting propellant during Atlas booster section jettison. There was no tracking camera footage of this event on Ranger 6's launch, which had occurred on an overcast day, but film of other Atlas launches showed that a large white plume enveloped the launch vehicle after staging. Convair technicians confirmed that 51 kilograms (112 lb) of LOX was vented from the Atlas after staging, but although the shock wave theory seemed tempting, James Kendall, another Jet Propulsion Laboratory physicist, dismissed it out of hand. The idea of an electrostatic discharge was also unlikely given the thinning air and high altitude of the Atlas when staging occurred. +Bratenahl persisted and studied more film of Atlas launches with the frames enlarged, which revealed light flashes in the post-staging plume. Another phone call to Convair revealed that 30 kilograms (67 lb) of RP-1 were also dumped during staging and that the Atlas's sustainer engine exhaust ignited the propellant cloud, producing these flashes. Since the umbilical door on the payload shroud was only held in place with a thin latching mechanism, hot gases from igniting propellant could have contacted the electrical connector and caused a short. The inadvertent activation of the telemetry system during launch had occurred almost simultaneously with booster jettison at T+140 seconds. With that, the book could be closed on the cause of Ranger 6's failure. +Among the changes made for Ranger 7 included new procedures to apply full power testing to the spacecraft off of the launch pad, where there was no risk of the midcourse correction engine activating on top of a fully fueled Atlas-Agena. +Jet Propulsion Laboratory had originally wanted to have Ranger 7 impact in the same general area as Ranger 6 so the impact crater could be imaged, but lighting conditions during July would not be favorable so they instead decided to go for a little-known area 11° south of the Moon's equator near the Sea of Storms. The probe was shipped to Cape Canaveral in mid-June along with Atlas 250D and Agena 6009. + +== Spacecraft design == + +Rangers 6, 7, 8 and 9 were called Block 3 versions of the Ranger spacecraft. The spacecraft consisted of a hexagonal aluminum frame base 1.5 meters (4 ft 11 in) across on which was mounted the propulsion and power units, topped by a truncated conical tower which held the TV cameras. Two solar panel wings, each 739 millimeters (29.1 in) wide by 1,537 millimeters (60.5 in) long, extended from opposite edges of the base with a full span of 4.6 meters (15 ft), and a pointable high-gain dish antenna was hinge mounted at one of the corners of the base away from the solar panels. A cylindrical quasi-omnidirectional antenna was seated on top of the conical tower. The overall height of the spacecraft was 3.6 meters (12 ft). +Propulsion for the mid-course trajectory correction was provided by a 224-newton (50 lbf) thrust monopropellant hydrazine engine with four jet-vane vector control. Orientation and attitude control about three axes was enabled by twelve nitrogen gas jets coupled to a system of three gyros, four primary Sun sensors, two secondary Sun sensors, and an Earth sensor. Power was supplied by 9,792 silicon solar cells contained in the two solar panels, giving a total array area of 2.3 square meters (25 sq ft) and producing 200 W. Two 1200 watt-hour AgZnO batteries rated at 26.5 V with a capacity for 9 hours of operation provided power to each of the separate communication/TV camera chains. Two 1000 watt-hour AgZnO batteries stored power for spacecraft operations. +Communications were through the quasi-omnidirectional low-gain antenna and the parabolic high-gain antenna. Transmitters aboard the spacecraft included a 60 W TV channel F at 959.52 MHz, a 60 W TV channel P at 960.05 MHz, and a 3 W transponder channel 8 at 960.58 MHz. The telecommunications equipment converted the composite video signal from the camera transmitters into an RF signal for subsequent transmission through the spacecraft high-gain antenna. Sufficient video bandwidth was provided to allow for rapid framing sequences of both narrow- and wide-angle television pictures. + +== Mission profile == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_7-2.md b/data/en.wikipedia.org/wiki/Ranger_7-2.md new file mode 100644 index 000000000..45be336f7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_7-2.md @@ -0,0 +1,31 @@ +--- +title: "Ranger 7" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Ranger_7" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:51.327735+00:00" +instance: "kb-cron" +--- + +On July 6, Ranger 7 completed its ground testing and was stacked atop the booster. On July 9, a NASA committee met and deemed the booster and spacecraft fully ready for launch, which was targeted for the 27th. +The first countdown on July 27 failed due to a defective battery in the Atlas and a problem with the ground guidance equipment. The next day, all went smoothly and Ranger 7 lifted off from LC-12 at 12:50 PM EST. The weather was clear and cloudless on this launch and Atlas staging was observed by tracking cameras. The expected propellant cloud enveloped the booster, but no anomalous events occurred this time. Thirty minutes after liftoff, the Agena restarted to boost Ranger 7 on a trajectory towards the Moon. +The flight trajectory for Ranger 7 was quite accurate, but a short midcourse correction was carried out early on the morning of July 29 to ensure impact in the Sea of Storms instead of the far side of the Moon. The warmup period for the TV cameras would be performed earlier and made shorter than on Ranger 6. Out of fear of jeopardizing the mission, ground controllers decided that the probe's orientation was acceptable enough and they would not risk maneuvering with the attitude control thrusters to get into a better angle. At 6:09 AM PDT, the first video imagery reached Earth. +As Ranger 7 sped towards the surface of the Moon, TV camera performance remained normal. Images of the cratered lunar surface continued to filter back to JPL headquarters in Pasadena, California, and finally, at 6:25, impact occurred and all signals from the probe ceased. In the JPL control room, there was "rapturous celebration". Ranger 7 had delivered the first close-distance imagery of the lunar surface and "more than anything, even the manned Mercury missions, had at last undone the sting Americans felt at Sputnik 1's launch". +The photographs returned from the probe found that the Moon was most likely "very craggy and rocky with debris everywhere". After speaking to the media, NASA officials were peppered with the obvious question – did the Moon have a surface solid enough that humans could safely land on it? Geologist Gerard Kuiper replied that judging by the images, it seemed likely that at least some of the Moon was smooth enough to land a spacecraft on. However, the actual hardness of the surface couldn't be determined with certainty until a soft landing was made. Nonetheless, Ranger 7's images did seem to suggest that it was solid enough. +Ranger 7 reached the Moon on July 31. The F-channel began its one-minute warm-up 18 minutes before impact. The first image was taken at 13:08:45 UT at an altitude of 2,110 kilometers (1,310 mi). Transmission of 4,308 photographs of excellent quality occurred over the final 17 minutes of flight. The final image taken before impact has a resolution of 0.5 meters (1.6 ft). The spacecraft encountered the lunar surface in direct motion along a hyperbolic trajectory, with an incoming asymptotic direction at an angle of -5.57° from the lunar equator. The orbit plane was inclined 26.84° to the lunar equator. After 68.6 hours of flight, Ranger 7 impacted in an area between Mare Nubium and Oceanus Procellarum (subsequently named Mare Cognitum) at 10.6340°S 20.6771°W / -10.6340; -20.6771. (The impact site is listed as 10.63 S, 20.66 W in the initial report "Ranger 7 Photographs of the Moon".) Impact occurred at 13:25:48.82 UT at a velocity of 2.62 km/s (1.63 mi/s). The spacecraft performance was excellent and the success of the mission finally brought a turnaround in NASA's fortunes after the endless string of lunar probe failures since 1958. + +Ranger 7 is credited for beginning the "peanut" tradition at NASA command stations. On the success of Ranger 7, someone in the control room was noticed eating peanuts. Since 1964, control rooms ceremonially open a container of peanuts for luck and tradition. + +== See also == + +Ranger program +Timeline of Solar System exploration +List of artificial objects on the Moon +List of missions to the Moon + +== References == + +== External links == +Images taken by Ranger 7 +"Lunar Bridgehead: The Ranger 7 Story" on YouTube \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_8-0.md b/data/en.wikipedia.org/wiki/Ranger_8-0.md new file mode 100644 index 000000000..2d15e36f4 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_8-0.md @@ -0,0 +1,54 @@ +--- +title: "Ranger 8" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Ranger_8" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:52.525104+00:00" +instance: "kb-cron" +--- + +Ranger 8 was a lunar probe in the Ranger program, a robotic spacecraft series launched by NASA in the early-to-mid-1960s to obtain the first close-up images of the Moon's surface. These pictures helped select landing sites for Apollo missions and were used for scientific study. During its 1965 mission, Ranger 8 transmitted 7,137 lunar surface photographs before it crashed into the Moon as planned. This was the second successful mission in the Ranger series, following Ranger 7. Ranger 8's design and purpose were very similar to those of Ranger 7. It had six television vidicon cameras: two full-scan and four partial-scan. Its sole purpose was to document the Moon's surface. + + +== Spacecraft design == + + +=== General === + +Ranger spacecraft were originally designed, beginning in 1959, in three distinct phases called "blocks". Rangers 6, 7, 8, and 9 were the Block 3 versions. The spacecraft consisted of a hexagonal aluminum frame base 1.5 m across on which was mounted the propulsion and power units, topped by a truncated conical tower that held the television cameras. Two solar panel wings, each 739 mm wide by 1537 mm long, extended from opposite edges of the base with a full span of 4.6 m, and a pointable high-gain dish antenna was hinge mounted at one of the corners of the base away from the solar panels. A cylindrical quasi-omnidirectional antenna was seated on top of the conical tower. The overall height of the spacecraft was 3.6 m. +Propulsion for the mid-course trajectory correction was provided by a 224 N thrust monopropellant hydrazine engine with four jet-vane vector control. Orientation and attitude control about three axes was enabled by twelve nitrogen gas jets coupled to a system of three gyroscopes, four primary Sun sensors, two secondary Sun sensors, and an Earth sensor. Power was supplied by 9,792 silicon solar cells contained in the two solar panels, giving a total array area of 2.3 square meters and producing 200 W. Two 1200-watt-hour AgZnO batteries rated at 26.5 V with a capacity for 9 hours of operation provided power to each of the separate communication/TV camera chains. Two 1000-watt-hour AgZnO batteries stored power for spacecraft operations. + + +=== Cameras === +The spacecraft carried six television vidicon cameras —two wide-angle (channel F, cameras A and B) and four narrow-angle (channel P) —to accomplish these objectives. The cameras were arranged in two separate chains, or channels; each was self-contained with separate power supplies, timers, and transmitters, to afford the greatest reliability and probability of obtaining high-quality television pictures. No other experiments were carried on the spacecraft. + + +=== Communications === +Communications were through the quasiomnidirectional low-gain antenna and the parabolic high-gain antenna. Transmitters aboard the spacecraft included a 60-watt television channel F at 959.52 MHz, a 60-watt television channel P at 960.05 MHz, and a 3-watt transponder channel 8 at 960.58 MHz. The telecommunications equipment converted the composite video signal from the camera transmitters into a radio-frequency signal for subsequent transmission through the spacecraft's high-gain antenna. Sufficient video bandwidth was provided to allow for rapid framing sequences of both narrow- and wide-angle television pictures. + + +== Mission profile == + +The Atlas 196D and Agena B 6006 boosters performed nominally, injecting the Agena and Ranger 8 into an Earth parking orbit at 185 km altitude after launch. Fourteen minutes later a 90-second burn of the Agena put the spacecraft into lunar transfer trajectory, and several minutes later the Ranger and Agena separated. The Ranger solar panels were deployed, attitude control activated, and spacecraft transmissions switched from the omniantenna to the high-gain antenna by 21:30 UT. On February 18, at a distance of 160,000 km from Earth, the planned mid-course maneuver took place, involving reorientation and a 59-second rocket burn. During the 27-minute maneuver, spacecraft transmitter power dropped severely, so that lock was lost on all telemetry channels. This continued intermittently until the rocket burn ended, at which time power returned to normal. The telemetry dropout had no serious effects on the mission. A planned terminal sequence to point the cameras more in the direction of flight just before reaching the Moon was cancelled to allow the cameras to cover a greater area of the Moon's surface. + +Ranger 8 reached the Moon on February 20, 1965. The first image was taken at 9:34:32 UT at an altitude of 2510 km. Transmission of 7,137 photographs of good quality occurred over the final 23 minutes of flight. The final image taken before impact has a resolution of 1.5 meters. The spacecraft encountered the lunar surface in a direct hyperbolic trajectory, with incoming asymptotic direction at an angle of −13.6 degrees from the lunar equator. The orbit plane was inclined 16.5 degrees to the lunar equator. After 64.9 hours of flight, impact occurred at 09:57:36.756 UT on February 20, 1965, in Mare Tranquillitatis at approximately 2.67° N, 24.65° E. (The impact site is listed as about 2.72° N, 24.61° E in the initial report "Ranger 8 Photographs of the Moon".) Impact velocity was slightly less than 2.68 km/s, approximately 6,000 mph. The spacecraft performance was excellent. +The impact crater of Ranger 8, approximately 13.5 m wide, was later photographed by Lunar Orbiter 4. + + +== See also == + +List of artificial objects on the Moon +List of missions to the Moon +Timeline of Solar System exploration + + +== References == + This article incorporates public domain material from Ranger 8. National Aeronautics and Space Administration. + + +== External links == +Lunar impact: A history of Project Ranger (PDF), R. Cargill Hall, 1977 +Photographs from Ranger 8 +Video from Ranger 8dead link + This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ranger_9-0.md b/data/en.wikipedia.org/wiki/Ranger_9-0.md new file mode 100644 index 000000000..7ad40acf6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ranger_9-0.md @@ -0,0 +1,43 @@ +--- +title: "Ranger 9" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Ranger_9" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:53.874999+00:00" +instance: "kb-cron" +--- + +Ranger 9 was a Lunar probe, launched in 1965 by NASA. It was designed to achieve a lunar impact trajectory and to transmit high-resolution photographs of the lunar surface during the final minutes of flight up to impact. The spacecraft carried six television vidicon cameras—two wide-angle (channel F, cameras A and B) and four narrow-angle (channel P)—to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality television pictures. These images were broadcast live on television to millions of viewers across the United States. No other experiments were carried on the spacecraft. + + +== Spacecraft design == + +Rangers 6, 7, 8, and 9 were the so-called Block 3 versions of the Ranger spacecraft. The spacecraft consisted of a hexagonal aluminium frame base 1.5 m across on which was mounted the propulsion and power units, topped by a truncated conical tower which held the TV cameras. Two solar panel wings, each 739 mm wide by 1537 mm long, extended from opposite edges of the base with a full span of 4.6 m, and a pointable high-gain dish antenna was hinge mounted at one of the corners of the base away from the solar panels. A cylindrical quasiomnidirectional antenna was seated on top of the conical tower. The overall height of the spacecraft was 3.6 m. +Propulsion for the mid-course trajectory correction was provided by a 224-N thrust monopropellant hydrazine engine with four jet-vane thrust vectoring. Orientation and attitude control about three axes was enabled by 12 nitrogen gas jets coupled to a system of three gyroscopes, four primary Sun sensors, two secondary Sun sensors, and an Earth sensor. Power was supplied by 9792 Si solar cells contained in the two solar panels, giving a total array area of 2.3 square meters and producing 200 W. Two 1,200 watt-hour batteries rated at 26.5 V with a capacity for 9 hours of operation provided power to each of the separate communication/TV camera chains. Two 1,000 watt-hour batteries stored power for spacecraft operations. +Communications were through the quasiomnidirectional low-gain antenna and the parabolic high-gain antenna. Transmitters aboard the spacecraft included a 60 W TV channel F at 959.52 MHz, a 60 W TV channel P at 960.05 MHz, and a 3 W transponder channel 8 at 960.58 MHz. The telecommunications equipment converted the composite video signal from the camera transmitters into an RF signal for subsequent transmission through the spacecraft high-gain antenna. Sufficient video bandwidth was provided to allow for rapid framing sequences of both narrow and wide-angle television pictures. + + +== Mission profile == + +The Atlas 204D and Agena B 6007 boosters performed nominally, injecting the Agena and Ranger 9 into an Earth parking orbit at 185-kilometre (115 mi) altitude. A 90-second Agena second burn put the spacecraft into lunar transfer trajectory. This was followed by the separation of the Agena and Ranger. Seventy minutes after launch, the command was given to deploy solar panels, activate attitude control, and switch from the omniantenna to the high-gain antenna. The accuracy of the initial trajectory enabled delay of the planned mid-course correction from 22 to 23 March when the maneuver was initiated at 12:03 UT. After orientation, a 31-second rocket burn at 12:30 UT, and reorientation, the maneuver was completed at 13:30 UT. +Ranger 9 reached the Moon on 24 March 1965. At 13:31 UTC, a terminal maneuver was executed to orient the spacecraft so the cameras were more in line with the flight direction to improve the resolution of the pictures. 20 minutes before impact, the one-minute camera system warm-up began. The first image was taken at 13:49:41 UTC at an altitude of 2,363 kilometres (1,468 mi). Transmission of 5,814 good contrast photographs was made during the final 19 minutes of flight. The final image taken before impact has a resolution of 0.3 metres (12 in). The spacecraft encountered the lunar surface with an incoming asymptotic direction at an angle of -5.6 degrees from the lunar equator. The orbit plane was inclined 15.6 degrees to the lunar equator. After 64.5 hours of flight, impact occurred at 14:08:19.994 UTC at approximately 12.83 S latitude, 357.63 E longitude in the Alphonsus crater. Impact velocity was 2,670 metres per second (8,800 ft/s). The spacecraft performance was excellent. Real-time television coverage with live network broadcasts of many of the F-channel images (primarily camera B but also some camera A pictures) were provided for this flight. + + +== See also == + +Ranger program +Timeline of Solar System exploration +List of artificial objects on the Moon +List of missions to the Moon + + +== References == + + +== External links == +Lunar impact: A history of Project Ranger (PDF) 1977 +The Ranger 9 Flight Path And Its Determination From Tracking Data (PDF) 1968 +Millions watch space probe crash into Moon (BBC News) +Photographs from Ranger 9 +Live video from Ranger 9 NASA \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Richard_Bryan-0.md b/data/en.wikipedia.org/wiki/Richard_Bryan-0.md new file mode 100644 index 000000000..585aee7ab --- /dev/null +++ b/data/en.wikipedia.org/wiki/Richard_Bryan-0.md @@ -0,0 +1,44 @@ +--- +title: "Richard Bryan" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Richard_Bryan" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:51.253154+00:00" +instance: "kb-cron" +--- + +Richard Hudson Bryan (born July 16, 1937) is an American retired politician and attorney who served as the 25th governor of Nevada from 1983 to 1989 and as a United States senator representing Nevada from 1989 until 2001. A Democrat, Bryan previously served as the state's attorney general and a member of the State Senate. + + +== Early life == +Bryan was born in Washington, D.C., and graduated from the University of Nevada at Reno in 1959 where he was a member of Alpha Tau Omega and the president of ASUN. He earned his J.D. degree from the University of California, Hastings College of the Law. In 1963 he was admitted to the Nevada Bar. He was Clark County's first public defender. + + +== Political career == + +Bryan served as a member of the Nevada Senate from 1972 to 1978. In 1979, Bryan became the Nevada Attorney General, and served in the position until 1983. + + +=== Governor of Nevada === +In 1982, Bryan challenged incumbent Republican Nevada Governor Robert List, who was running for reelection. He defeated List and became governor in January 1983. Bryan was easily reelected in 1986, defeating Nevada State Treasurer Patricia Cafferata. +He became known for his frequent invitations to state legislators to join the governor for meals at the governor's mansion. The practice created goodwill between the governor and legislators of both parties. + + +=== U.S. Senate === +By 1987, Bryan was encouraged by several prominent politicians, including Harry Reid and Alan Cranston, to run for the U.S. Senate. He declared his candidacy shortly after, and in the 1988 U.S. Senate election, he defeated incumbent Republican Senator Chic Hecht. He was sworn in at the convening of the 101st Congress on January 3, 1989. During his tenure in the Senate, Bryan served on the Finance, Banking, Intelligence and Commerce Committees. +Bryan was an opponent of Search for extraterrestrial intelligence (SETI), stating: "As of today millions have been spent and we have yet to bag a single little green fellow. Not a single Martian has said take me to your leader, and not a single flying saucer has applied for FAA approval." He introduced an amendment to the 1994 budget that secured the cancellation of the High Resolution Microwave Survey and terminated NASA's SETI efforts less than one year after their launch. Bryan ran for reelection in the Senate in 1994, easily defeating Republican challenger Hal Furman. +Bryan also focused on preventing Yucca Mountain from being used as a nuclear waste long-term storage site. Though the Yucca Mountain nuclear waste repository would be built during Bryan's time in the Senate, his opposition delayed any actual storage from occurring. This opposition would continue after Bryan had retired before plans for storage were discontinued by President Barack Obama. +Bryan opted not to run for a third term in the Senate in 2000. + + +== References == + + +== External links == + +United States Congress. "Richard Bryan (id: B000993)". Biographical Directory of the United States Congress. +A Guide to the U.S. Senatorial Papers of Richard H. Bryan, Special Collections, University Libraries, University of Nevada, Reno. +How Richard Bryan destroyed the NASA's SETI project +Richard H Bryan's current professional page +Appearances on C-SPAN \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Riken-0.md b/data/en.wikipedia.org/wiki/Riken-0.md new file mode 100644 index 000000000..3629d39da --- /dev/null +++ b/data/en.wikipedia.org/wiki/Riken-0.md @@ -0,0 +1,110 @@ +--- +title: "Riken" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Riken" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:14:57.846079+00:00" +instance: "kb-cron" +--- + +Riken (Japanese: 理研; English: ; stylized in all caps as RIKEN) is a national scientific research institute in Japan. Founded in 1917, it now has about 3,000 scientists on seven campuses across Japan, including the main site at Wakō, Saitama Prefecture, on the outskirts of Tokyo. Riken is a Designated National Research and Development Institute, and was formerly an Independent Administrative Institution. +Riken conducts research in various fields of science, including physics, chemistry, biology, genomics, medical science, engineering, high-performance computing and computational science, and ranging from basic research to practical applications with 485 partners worldwide. It is almost entirely funded by the Japanese government, with an annual budget of ¥100 billion (US$750 million) in FY2023. + + +== Name == +"Riken" is an acronym of the formal name Rikagaku Kenkyūsho (理化学研究所), and its full name in Japanese is Kokuritsu Kenkyū Kaihatsu Hōjin Rikagaku Kenkyūsho (国立研究開発法人理化学研究所) and in English is the Institute of Physical and Chemical Research. + + +== History == + +In 1913, the well-known scientist Jokichi Takamine first proposed the establishment of a national science research institute in Japan. This task was taken on by Viscount Shibusawa Eiichi, a prominent businessman, and following a resolution by the Diet in 1915, Riken came into existence in March 1917. In its first incarnation, Riken was a private foundation (財団法人, zaidan), funded by a combination of industry, the government, and the Imperial Household. It was located in the Komagome district of Tokyo, and its first director was the mathematician Baron Dairoku Kikuchi. +In 1927, Viscount Masatoshi Ōkōchi, the third director, established the Riken Concern (a zaibatsu). This was a group of spin-off companies that used Riken's scientific achievements for commercial ends and returned the profits to Riken. At its peak in 1939 the zaibatsu comprised about 121 factories and 63 companies, including Riken Kankōshi, which is now Ricoh. +During World War II, the Japanese army's atomic bomb program was conducted at Riken. In April 1945 the US bombed Riken's laboratories in Komagome, and in November, after the end of the war, Allied soldiers destroyed its two cyclotrons. +After the war, the Allies dissolved Riken as a private foundation, and it was brought back to life as a company called Kagaku Kenkyūsho (科学研究所), or Kaken (科研). In 1958 the Diet passed the Riken Law, whereby the institute returned to its original name and entered its third incarnation, as a public corporation (特殊法人, tokushu hōjin), funded by the government. In 1963 it relocated to a large site in modern day Wakō then until 1970 in Saitama Prefecture, just outside Tokyo. +Since the 1980s Riken has expanded dramatically. New labs, centers, and institutes have been established in Japan and overseas, including: + +in 1984, the Life Science Center in Tsukuba +in 1995, the Muon Research Facility at the Rutherford Appleton Laboratory in the UK +in 1997, the Harima Institute, the Brain Science Institute in Wako, and the center at the Brookhaven National Laboratory in the United States of America +in 1998, the Genomic Sciences Center +in 2000, the Yokohama Institute, which now contains four centers for research in the life sciences +in 2002, the Kobe Institute, which contains the Center for Developmental Biology +In October 2003, Riken's status changed again, to Independent Administrative Institution. As such, Riken is still publicly funded, and it is periodically evaluated by the government, but it has a higher degree of autonomy than before. Riken is regarded as the flagship research institute in Japan and conducts basic and applied experimental research in a wide range of science and technology fields including physics, chemistry, medical science, biology and engineering. +Riken was the subject of international attention in 2014 after the Stimulus-triggered acquisition of pluripotency cell (also known as STAP) publication, investigation, retraction, and suicide of Yoshiki Sasai, the principal investigator. + + +== Organizational structure == + +The main divisions of Riken are listed here. Purely administrative divisions are omitted. + +Headquarters (mostly in Wako) +Wako Branch +Center for Emergent Matter Science (research on new materials for reduced power consumption) +Center for Sustainable Resource Science (research toward a sustainable society) +Nishina Center for Accelerator-Based Science (site of the Radioactive Isotope Beam Factory, a heavy-ion accelerator complex) +Center for Brain Science +Center for Advanced Photonics (research on photonics including terahertz radiation) +Research Cluster for Innovation +Cluster for Pioneering Research (chief scientists) +Interdisciplinary Theoretical and Mathematical Sciences Program +Tokyo Branch +Center for Advanced Intelligence Project (research on artificial intelligence) +Tsukuba Branch +BioResource Research Center +Harima Institute +Riken SPring-8 Center (site of the SPring-8 synchrotron and the SACLA x-ray free electron laser) +Yokohama Branch (site of the Yokohama Nuclear magnetic resonance facility) +Center for Sustainable Resource Science +Center for Integrative Medical Sciences (research toward personalized medicine) +Center for Biosystems Dynamics Research (also based in Kobe and Osaka) +Program for Drug Discovery and Medical Technology Platform +Structural Biology Laboratory +Sugiyama Laboratory +Kobe Branch +Center for Biosystems Dynamics Research (developmental biology and nuclear medicine medical imaging techniques) +Center for Computational Science (R-CCS, home of the Fugaku super computer and now decommissioned K computer) + + +== Achievements == +Two Riken scientists have won the Nobel prize for physics: Hideki Yukawa in 1949 and Shin'ichirō Tomonaga in 1965. +The SPring-8 (Super Photon Ring 8GeV) facility in Harima is one of the largest and most powerful third-generation synchrotron radiation facilities. +In July 2004 a team at Riken created element 113 (now named nihonium, after Nihon = Japan). On April 2, 2005 the same team successfully created it for the second time, and a third event was seen in 2012. The discovery was officially recognized by the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP) in December 2015. +The Riken Super Combined Cluster is one of the world's fastest supercomputers. In January 2006, Riken set up the Next-Generation Supercomputer R&D Center, with the purpose of designing and building the fastest supercomputer in the world, and in June 2006, it announced the completion of a one-petaFLOPS computer system designed specially for molecular dynamics simulation. While the K computer was being installed at Riken, in 2011 it topped the LINPACK benchmark with the performance of 8.162 petaFLOPS, or 8.162 quadrillion calculations per second, with a computing efficiency ratio of 93.0%, making it the fastest supercomputer in the world at the time. The complete project entered service in November 2012. + + +== List of presidents == +Dairoku Kikuchi (1917) +Kōi Furuichi (1917–1921) +Masatoshi Ōkōchi (1921–1946) +Yoshio Nishina (1946–1951) +Kiichi Sakatani (1951–1952) +Takeshi Murayama (1952–1956) +Masanori Satō (1956–1958) +Haruo Nagaoka (1958–1966) +Shirō Akahori (1966–1970) +Toshio Hoshino (1970–1975) +Shinji Fukui (1975–1980) +Tatsuoki Miyajima (1980–1988) +Minoru Oda (1988–1993) +Akito Arima (1993–1998) +Shunichi Kobayashi (1998–2003) +Ryōji Noyori (2003 – 31 March 2015) +Hiroshi Matsumoto (1 April 2015 – 31 March 2022) +Makoto Gonokami (1 April 2022–present) + + +== Notable scientists and affiliated people == + + +== See also == +Riken integrated database of mammals + + +== References == + + +== External links == + +Official website (in English and Japanese) +Riken Research (in English and Japanese) – A resource for up-to-date information on key achievements of Riken researchers. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Robert_H._Gray-0.md b/data/en.wikipedia.org/wiki/Robert_H._Gray-0.md new file mode 100644 index 000000000..ee30d6304 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Robert_H._Gray-0.md @@ -0,0 +1,57 @@ +--- +title: "Robert H. Gray" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Robert_H._Gray" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:20.956628+00:00" +instance: "kb-cron" +--- + +Robert Hansen Gray (March 7, 1948 - December 6, 2021) was an American data analyst, author, and astronomer, and author of The Elusive Wow: Searching for Extraterrestrial Intelligence. + + +== Education == +Gray attended Shimer College, a Great Books school then located in Mount Carroll, Illinois, where he received a bachelor's degree in 1970. He went on to obtain a master's in urban planning and policy analysis from the University of Illinois at Chicago in 1980. + + +== Career == + + +=== Data analysis === +In 1984, Gray founded the company Gray Data in Chicago, which provided data analysis research services and published reference cards for microcomputer software. He continued to work as a data analyst through his company Gray Consulting. + + +=== Search for Extraterrestrial Intelligence (SETI) === +Gray is best known for his work as an independent SETI researcher. The Atlantic called Gray "the 'Wow!' signal's most devoted seeker and chronicler, having traveled to the very ends of the earth in search of it." +The Wow! signal was detected by the Ohio State University Radio Observatory (also known as Big Ear) on August 15, 1977. The signal was so pronounced in the data, and so similar to a radio signal rather than a natural source, that SETI scientist Jerry R. Ehman circled it on the computer printout in red ink and wrote "Wow!" next to it. After hearing about the Wow! signal a few years after its detection, Gray contacted the Ohio team, visited Big Ear, and spoke with Ehman, Robert S. Dixon (director of the SETI project) and John D. Kraus (the telescope's designer). +In 1980, Gray began scanning the skies from his backyard in Chicago, using a 12-foot commercial telecommunications dish. He operated his small SETI radio observatory regularly beginning in 1983 and for the next 15 years, but did not find a trace of the Wow! signal. In 1987 and 1989 he led searches for the signal using the Harvard/Smithsonian META radio telescope at the Oak Ridge Observatory in Harvard, Massachusetts. In September 1995 and again in May 1996, Gray and Kevin B. Marvel reported searches for the signal using the Very Large Array (VLA) radio telescope in New Mexico (which is an array of 27 dishes simulating a single dish with a diameter of up to 22 miles), becoming the first amateur astronomer to use the VLA, and the first individual to use it to search for extraterrestrial signals. The VLA was, until the end of the twentieth century, the most powerful radio telescope ever built. In 1998, he and University of Tasmania professor Simon Ellingsen conducted searches using the 26-meter dish at the Mount Pleasant Radio Observatory in Hobart, Tasmania. Gray and Ellingsen made six 14-hour observations where the Big Ear was pointing when it found the Wow! signal, searching for intermittent and possibly periodic signals, rather than a constant signal. No signals resembling the Wow! were detected. + + +=== Writing === +Gray and Marvel published a 2001 paper in The Astrophysical Journal detailing his use of the VLA in search of the signal. Gray and Ellingsen published "A Search for Periodic Emissions at the Wow Locale" in the October 2002 issue of The Astrophysical Journal, reporting on searches for the Wow! signal. In 2011, Gray published the book The Elusive Wow: Searching for Extraterrestrial Intelligence, summarizing what is known about the Wow! signal, covering his own search for the signal, and offering an overview of the search for extraterrestrial intelligence. +In 2016, Gray published an article in Scientific American about the Fermi paradox, which claims that if extraterrestrials existed, we would see signs of them on Earth, because they would certainly colonize the galaxy by interstellar travel. Gray argued that the Fermi paradox, named after Nobel Prize-winning physicist Enrico Fermi, does not accurately represent Fermi's views. Gray stated that Fermi questioned the feasibility of interstellar travel, but did not say definitively whether or not he thought extraterrestrials exist. + + +== Personal life == +Gray lived in Chicago, Illinois, with his wife, photographer Sharon A. Hoogstraten. He died on December 6, 2021, from complications from lung cancer in Chicago. + + +== Bibliography == + + +=== Books === +Robert H. Gray, The Elusive Wow: Searching for Extraterrestrial Intelligence (Palmer Square Press, 2012) + + +=== Articles === +"A VLA Search for the Ohio State 'Wow'" The Astrophysical Journal, vol. 546, no. 2, January 2001 (with Kevin B. Marvel) +"A Search for Periodic Emissions at the Wow Locale" The Astrophysical Journal, vol. 578, no. 2, October 2002 (with Simon Ellingsen) +"A VLA Search for Radio Signals from M31 and M33" The Astrophysical Journal, vol. 153, no. 3, February 2017 (with Kunal Mooley) +"An ATA Search for a Repetition of the Wow Signal" The Astrophysical Journal, vol. 160, no. 4, September 2020 (with Gerald Harp, Jon Richards, Seth Shostak, and Jill Tarter) +"The Fermi Paradox Is Not Fermi's, and It Is Not a Paradox" Scientific American, January 29, 2016 (first appeared in Astrobiology, vol. 15, issue 3, March 2015) +"The Extended Kardashev Scale" Astronomical Journal, vol. 159, no. 5, April 2020 +"Intermittent Signals and Planetary Days in SETI" Intl. Journal of Astrobiology, vol. 19, April 2020 + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-0.md b/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-0.md new file mode 100644 index 000000000..0098d44e7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-0.md @@ -0,0 +1,44 @@ +--- +title: "Ronald N. Bracewell" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Ronald_N._Bracewell" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:47.668859+00:00" +instance: "kb-cron" +--- + +Ronald Newbold Bracewell AO (22 July 1921 – 12 August 2007) was the Lewis M. Terman Professor of Electrical Engineering of the Space, Telecommunications, and Radioscience Laboratory at Stanford University. + +== Education == + +Bracewell was born in Sydney, in 1921, and educated at Sydney Boys High School. He graduated from the University of Sydney in 1941 with the BSc degree in mathematics and physics, later receiving the degrees of B.E. (1943), and M.E. (1948) with first class honours, and while working in the Engineering Department became the President of the Oxometrical society. During World War II he designed and developed microwave radar equipment in the Radiophysics Laboratory of the Commonwealth Scientific and Industrial Research Organisation, Sydney under the direction of Joseph L. Pawsey and Edward G. Bowen and from 1946 to 1949 was a research student at Sidney Sussex College, Cambridge, engaged in ionospheric research in the Cavendish Laboratory, where in 1949 he received his PhD degree in physics under J. A. Ratcliffe. + +== Career == +From October 1949 to September 1954, Dr. Bracewell was a senior research officer at the Radiophysics Laboratory of the CSIRO, Sydney, concerned with very-long-wave propagation and radio astronomy. He then lectured in radio astronomy at the Astronomy Department of the University of California, Berkeley, from September 1954 to June 1955 at the invitation of Otto Struve, and at Stanford University during the summer of 1955, and joined the Electrical Engineering faculty at Stanford in December 1955. +In 1974 he was appointed the first Lewis M. Terman Professor and Fellow in Electrical Engineering (1974–1979). Though he retired in 1979, he continued to be active until his death. + +== Contributions and honours == +Professor Bracewell was a Fellow of the Royal Astronomical Society (1950), Fellow and life member of the Institute of Electrical and Electronics Engineers (1961), Fellow of the American Association for the Advancement of Science (1989), and was a Fellow with other significant societies and organisations. +For experimental contributions to the study of the ionosphere by means of very low frequency waves, Dr. Bracewell received the Duddell Premium of the Institution of Electrical Engineers, London in 1952. In 1992 he was elected to foreign associate membership of the Institute of Medicine of the U.S. National Academy of Sciences (1992), the first Australian to achieve that distinction, for fundamental contributions to medical imaging. He was one of Sydney University's three honourees when alumni awards were instituted in 1992, with a citation for brain scanning, and was the 1994 recipient of the Institute of Electrical and Electronics Engineers' Heinrich Hertz medal for pioneering work in antenna aperture synthesis and image reconstruction as applied to radio astronomy and to computer-assisted tomography. In 1998 Dr. Bracewell was named Officer of the Order of Australia (AO) for service to science in the fields of radio astronomy and image reconstruction. +At CSIRO Radiophysics Laboratory, work that in 1942–1945 was classified appeared in a dozen reports. Activities included design, construction, and demonstration of voice-modulation equipment for a 10 cm magnetron (July 1943), a microwave triode oscillator at 25 cm using cylindrical cavity resonators, equipment designed for microwave radar in field use (wavemeter, echo box, thermistor power meter, etc.) and microwave measurement technique. Experience with numerical computation of fields in cavities led, after the war, to a Master of Engineering degree (1948) and the definitive publication on step discontinuities in radial transmission lines (1954). +While at the Cavendish Laboratory, Cambridge (1946–1950) Bracewell worked on observation and theory of upper atmospheric ionisation, contributing to experimental technique (1948), explaining solar effects (1949), and distinguishing two layers below the E-layer (1952), work recognised by the Duddell Premium. +While at Stanford, Professor Bracewell constructed a microwave spectroheliograph (1961), a radio telescope comprising 32 10 ft dishes arranged in a cross, which produced daily temperature maps of the Sun reliably for eleven years, the duration of a solar cycle. The first radio telescope to give output automatically in printed form, and therefore capable of worldwide dissemination by teleprinter, its daily solar weather maps received acknowledgement from NASA for support of the first crewed landing on the Moon. Subsequently, five larger 60 ft dishes were built at the same site, and were eventually removed in 2006 after efforts to preserve the site. Bracewell was interviewed during the destruction of the dishes. +Many fundamental papers on restoration (1954–1962), interferometry (1958–1974) and reconstruction (1956–1961) appeared along with instrumental and observational papers. By 1961 the radio-interferometer calibration techniques developed for the spectroheliograph first allowed an antenna system, with 52-inch fan beam, to equal the angular resolution of the human eye in one observation. With this beam the components of Cygnus A, spaced 100-inch, were put directly in evidence without the need for repeated observations with variable spacing aperture synthesis interferometry. +The nucleus of the extragalactic source Centaurus A was resolved into two separate components whose right ascensions were accurately determined with a 2.3-minute fan beam at 9.1 cm. Knowing that Centaurus A was composite, Bracewell used the 6.7-minute beam of the Parkes Observatory 64 m radio telescope at 10 cm to determine the separate declinations of the components and in so doing was the first to observe strong polarisation in an extragalactic source (1962), a discovery of fundamental significance for the structure and role of astrophysical magnetic fields. Subsequent observations made at Parkes by other observers with a 14-minute and wider beams at 21 cm and longer wavelengths, though not resolving the components, were compatible with the + + + + + λ + + 2 + + + + + {\displaystyle \lambda ^{2}} + + dependence expected from Faraday rotation if magnetic fields were the polarising agent. +A second major radiotelescope (1971) employing advanced concepts to achieve an angular resolution of 18 seconds of arc was designed and built at Stanford and applied to both solar and galactic studies. The calibration techniques for this leading-edge resolution passed into general use in radio interferometry via the medium of alumni. +Upon the discovery of the cosmic background radiation: \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-1.md b/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-1.md new file mode 100644 index 000000000..668c15bb6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-1.md @@ -0,0 +1,28 @@ +--- +title: "Ronald N. Bracewell" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Ronald_N._Bracewell" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:47.668859+00:00" +instance: "kb-cron" +--- + +a remarkable observational limit of 1.7 millikelvins, with considerable theoretical significance for cosmology, was set on the anisotropy in collaboration with PhD student E. K. Conklin (1967), and was not improved on for many years +the correct theory of a relativistic observer in a blackbody enclosure (1968) was given in the first of several papers by various authors obtaining the same result +the absolute motion of the Sun at 308 km/s through the cosmic background radiation was measured by Conklin in 1969, some years before independent confirmation. +With the advent of the space age, Bracewell became interested in celestial mechanics, made observations of the radio emission from Sputnik 1, and supplied the press with accurate charts predicting the path of Soviet satellites, which were perfectly visible, if you knew when and where to look. Following the puzzling performance of Explorer I in orbit, he published the first explanation (1958–59) of the observed spin instability of satellites, in terms of the Poinsot motion of a non-rigid body with internal friction. He recorded the signals from Sputniks I, II and III and discussed them in terms of the satellite spin, antenna polarisation, and propagation effects of the ionised medium, especially Faraday effect. +Later (1978, 1979) he invented a spinning, nulling, two-element infrared interferometer suitable for space-shuttle launching into an orbit near Jupiter, with milliarcsecond resolution, that could lead to the discovery of planets around stars other than the Sun. This concept was elaborated in 1995 by Angel and Woolf, whose space-station version with four-element double nulling became the Terrestrial Planet Finder (TPF), NASA's candidate for imaging planetary configurations of other stars. +Imaging in astronomy led to participation in development of computer assisted x-ray tomography, where commercial scanners reconstruct tomographic images using the algorithm developed by Bracewell for radioastronomical reconstruction from fan-beam scans. This corpus of work has been recognized by the Institute of Medicine, an award by the University of Sydney, and the Heinrich Hertz medal. Service on the founding editorial board of the Journal for Computer-Assisted Tomography, to which he also contributed publications, and on the scientific advisory boards of medical instrumentation companies maintained Bracewell's interest in medical imaging, which became an important part of his regular graduate lectures on imaging, and forms an important part of his 1995 text on imaging. +Experience with the optics, mechanics and control of radiotelescopes led to involvement with solar thermophotovoltaic energy at the time of the energy crisis, including the fabrication of low-cost solid and perforated paraboloidal reflectors by hydraulic inflation. +Bracewell is also known for being the first to propose the use of autonomous artificial intelligence powered interstellar space probes for communication between alien civilisations as an alternative to radio transmission dialogs. This hypothetical concept has been dubbed the Bracewell probe after its inventor. + +=== Fourier analysis === + +As a consequence of relating images to Fourier analysis, in 1983 he discovered a new factorisation of the discrete Fourier transform matrix leading to a fast algorithm for spectral analysis. This method, which has advantages over the fast Fourier algorithm, especially for images, is treated in The Hartley Transform (1986), in U.S. Patent 4,646,256 (1987, now in the public domain), and in over 200 technical papers by various authors that were stimulated by the discovery. Analogue methods of creating a Hartley transform plane first with light and later with microwaves were demonstrated in the laboratory and permitted the determination of electromagnetic phase by the use of square-law detectors. A new elementary signal representation, the Chirplet transform, was discovered (1991) that complements the Gabor elementary signal representations used in dynamic spectral analysis (with the property of meeting the bandwidth-duration minimum associated with the uncertainty principle). This advance opened a new field of adaptive dynamic spectra with wide application in information analysis. + +=== Other interests === + +Professor Bracewell was interested in conveying an appreciation of the role of science in society to the public, in mitigating the effects of scientific illiteracy on public decision making through contact with alumni groups, and in liberal undergraduate education within the framework of the Astronomy Course Program and the Western Culture program in Values, Technology, Science and Society, in both of which he taught for some years. He gave the 1996 Bunyan Lecture on The Destiny of Man. +He was also interested in the trees of Stanford's campus and published a book about them. He also taught an undergraduate seminar titled I Dig Trees. +Bracewell was also a designer and builder of sundials. He and his son Mark Bracewell built one on the South side of the Terman Engineering Building; after that building was demolished, a new home for the sundial, at the same orientation, was found on the Jen-Hsun Huang Engineering Center. He built another sundial at the home of his son, and another on the deck of professor John G. Linvill's house. The Bracewell Radio Sundial at the Very Large Array was built in his honor. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-2.md b/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-2.md new file mode 100644 index 000000000..0899c91b0 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Ronald_N._Bracewell-2.md @@ -0,0 +1,61 @@ +--- +title: "Ronald N. Bracewell" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Ronald_N._Bracewell" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:47.668859+00:00" +instance: "kb-cron" +--- + +== Selected publications == +Bracewell, Ronald N. and Pawsey, J. L., Radio Astronomy (Oxford, 1955) (also translated into Russian and reprinted in China) +Bracewell, Ronald N., Radio Interferometry of Discrete Sources (Proceedings of the IRE, January 1958) +Bracewell, Ronald N., ed., Paris Symposium on Radio Astronomy, IAU Symposium no. 9 and URSI Symposium no. 1, held July 30, 1958 – August 6, 1958 (Stanford Univ. Press, Stanford, CA, 1959) (also translated into Russian) +Professor Bracewell translated Radio Astronomy, by J. L. Steinberg and J. Lequeux, (McGraw-Hill, 1963) from French +Bracewell, Ronald N. (June 1999) [1985, 1978, 1965]. The Fourier Transform and Its Applications (3 ed.). McGraw-Hill. ISBN 978-0-07303938-1. (NB. Second edition also translated into Japanese and Polish.) +Bracewell, Ronald N., Trees on the Stanford Campus (Stanford: Samizdat, 1973) +Bracewell, Ronald N., The Galactic Club: Intelligent Life in Outer Space (Portable Stanford: Alumni Association, 1974) (also translated into Dutch, Japanese, and Italian) +Bracewell, Ronald N. (1986). The Hartley Transform. Oxford Engineering Science Series. Vol. 19 (1 ed.). New York: Oxford University Press, Inc. ISBN 0-19-503969-6. (NB. Also translated into German and Russian.) +Bracewell, Ronald N., Two-Dimensional Imaging (Prentice-Hall, 1995) +Bracewell, Ronald N., Fourier Analysis and Imaging (Plenum, 2004) +Bracewell, Ronald N., Trees of Stanford and Environs (Stanford Historical Society, 2005) + +== Chapter contributions == +Bracewell has contributed chapters to: + +Textbook of Radar Microwave Transmission and Cavity Resonator Theory, ed. E. G. Bowen, 1946 +Advances in Astronautical Sciences Satellite Rotation, ed. H. Jacobs, 1959 +The Radio Noise Spectrum Correcting Noise Maps for Beamwidth, ed. D. H. Menzel, 1960 +Modern Physics for the Engineer Radio Astronomy, ed. L. Ridenour and W. Nierenberg, 1960 +Statistical methods in Radio Wave Propagation Antenna Tolerance Theory, ed. W. C. Hoffman, 1960 +Advances in Geophysics Satellite Studies of the Ionization in Space by Radio, ed. H. E. Landsberg, 1961 (O. K. Garriott and Ronald N. Bracewell) +Handbuch der Physik Radio Astronomy Techniques, ed. S. Flugge, 1962 +Encyclopedia of Electronics Extraterrestrial Radio Noise, ed. C. Susskind, 1962 +Stars and Galaxies Radio Broadcasts from the Depths of Space, ed. T. L. Page, 1962 +Radio Waves and Circuits Aerials and Data Processing, ed. S. Silver, 1963 +Light and Life in the Universe Life in the Galaxy, ed. S. T. Butler and H. Messel, 1964 +Encyclopædia Britannica Telescope, Radio, 1967 +Vistas in Science The Microwave Sky, ed. David L. Arm, 1968 +Man in Inner and Outer Space The Sun (Five Chapters), ed. H. Messel and S. T. Butler, 1968 +Image Reconstruction from Projections: Implementation and Applications Image Reconstruction in Radio Astronomy, ed. G. Hermann, 1979 +Annual Review of Astronomy and Astrophysics Computer Image Processing, ed. G. Burbidge et al., 1979 +Energy for Survival How It All Began, Man the Lazy Animal, and Energy from Sunlight, ed. H. Messel, 1979 +Life in the Universe Manifestations of Advanced Civilizations, ed. J. Billingham, 1981 +Extraterrestrials: Where Are They? Preemption of the Galaxy by the First Advanced Civilization, ed. M. H. Hart and B. Zuckerman, 1982, 1995 +Transformations in Optical Signal Processing Fourier Inversion of Deficient Data, ed. W. T. Rhodes, J. R. Fienup and B. E. A. Saleh, 1984 +The Early Years of Radio Astronomy Early Work on Imaging Theory in Radio Astronomy, ed. W. T. Sullivan, III, 1984 +Indirect Imaging Inversion of Nonplanar Visibilities, ed. J. A. Roberts, 1984 +Fourier Techniques and Applications The Life of Joseph Fourier and Fourier Techniques and Applications, ed. J. F. Price, 1985 +Yearbook of Science and Technology Wavelets, 1996 +Encyclopedia of Applied Physics Fourier and Other Mathematical Transforms 1997 +Cornelius Lanczos—Collected Published Papers with Commentaries The Fast Fourier Transform andSmoothing Data by Analysis and by Eye ed. W. R. Davis et al., 1999 + +== See also == +cas (mathematics) + +== References == + +== External links == +Stanford Web Profile +Stanford Death Notice \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SACLA-0.md b/data/en.wikipedia.org/wiki/SACLA-0.md new file mode 100644 index 000000000..94d38040b --- /dev/null +++ b/data/en.wikipedia.org/wiki/SACLA-0.md @@ -0,0 +1,29 @@ +--- +title: "SACLA" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SACLA" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:07.156362+00:00" +instance: "kb-cron" +--- + +The SPring-8 Angstrom Compact free electron LAser, referred to as SACLA (pronounced さくら (Sa-Ku-Ra)), is an X-ray free-electron laser (XFEL) in Harima Science Garden City, Japan, embedded in the SPring-8 accelerator and synchrotron complex. When it first came into operation 2011, it was the second XFEL in the world and the first in Japan. + + +== Design == + +Like other XFELs, SACLA uses self-amplified spontaneous emission to achieve extremely high intensities of X-rays. SACLA uses in-vacuum, short-period undulators, which is one of the unique factors in its design that allows it to achieve sub-Ångstrom wavelengths of 0.6 Å at a relatively much shorter distance of 0.7 km, compared to other similar XFELs like LCLS (2 km) or the European XFEL (3.4 km). An 8.5 GeV electron beam is used as the source. + + +== Animated Short Films == +SACLA has released a number of animated short films to promote its research capabilities to the public. In July 2013, SACLA released two animated short films titled "Picotopia", which discussed the cellular biology, and "Wasureboshi", which is about conception. +On December 3, 2013, another animated short titled "Mirai Koshi: Harima SACLA" was released to promote the XFEL's ability to detect atoms and molecules. + + +== References == + + +== Further reading == +SACLA home page +First Light at SACLA \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SPring-8-0.md b/data/en.wikipedia.org/wiki/SPring-8-0.md new file mode 100644 index 000000000..5b5761fda --- /dev/null +++ b/data/en.wikipedia.org/wiki/SPring-8-0.md @@ -0,0 +1,40 @@ +--- +title: "SPring-8" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SPring-8" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:08.359476+00:00" +instance: "kb-cron" +--- + +SPring-8 (an acronym of Super Photon Ring – 8 GeV) is a synchrotron radiation facility located in Sayo Town, Sayo District, Hyōgo Prefecture, Japan, which is the main facility of Harima Science Garden City. It was developed jointly by RIKEN and the Japan Atomic Energy Research Institute, and is owned and managed by RIKEN, and run under commission by the Japan Synchrotron Radiation Research Institute. The machine consists of a storage ring containing an 8 GeV electron beam. On its path around the storage ring, the beam passes through insertion devices to produce synchrotron radiation with energies ranging from soft X-rays (300 eV) up to hard X-rays (300 keV). The synchrotron radiation produced at SPring-8 is used for materials analysis and biochemical protein characterization by many Japanese manufacturers and universities. +Together with the Advanced Photon Source at Argonne National Laboratory and the Cornell High Energy Synchrotron Source at Cornell University in the United States, the European Synchrotron Radiation Facility in Grenoble, France, and PETRA at DESY in Hamburg, Germany, it is one of the five large (beam energy greater than 5 GeV) synchrotron radiation facilities in the world. + + +== Research == +The Laser Electron Photon Experiment at SPring-8 (LEPS) is an experiment producing high-energy (GeV) photon beams by the inverse Compton scattering of photons upon the 8 GeV electrons of the SPring-8 synchrotron. These are then used for various particle physics experiments on hadrons. The first beam was produced in 1999, and data-taking commenced in 2000. + +The collaboration is known for their reports of a resonance which they interpret as a Θ+ pentaquark candidate made of two up quarks, two down quarks and a strange antiquark (uudds). The 2008 Review of Particle Physics of the Particle Data Group ruled out the existence of this resonance, but new reports from LEPS indicate that the resonance could be seen in the γd → K+K−pn channel. + + +== Use by police == +The materials analysis at SPring-8 can be used as forensics to identify substances for police investigations by detecting the types and combinations of impurities. For example, in the 1998 Wakayama curry poisoning incident, the arsenic used as the poisoning agent in a communal pot of curry contained trace impurities of bismuth and antimony, which were also present in arsenic found in the perpetrator's home. +In another case, evidence from SPring-8 led to the arrest of three former members of the Aum Shinrikyo cult suspected in the 1995 shooting of Takaji Kunimatsu, Japan's head of the National Police Agency at the time. Like the curry poisoning incident, impurities in the metal traces in the coat of a suspect were matched to impurities in the gun used in the shooting. + + +== In popular culture == +In the Ghost in the Shell: S.A.C. 2nd GIG anime series, SPring-8 is mentioned several times, and is the facility where the character Ishikawa takes a sample of weapons-grade Plutonium to be analyzed to verify its source. +In Salvation of a Saint, a piece of evidence is sent to SPring-8 for analysis. + + +== See also == +List of synchrotron radiation facilities + + +== References == + + +== External links == +SPring-8 website +LEPS Archived 2009-10-08 at the Wayback Machine \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SWEEPS-04-0.md b/data/en.wikipedia.org/wiki/SWEEPS-04-0.md new file mode 100644 index 000000000..e6e44a0ff --- /dev/null +++ b/data/en.wikipedia.org/wiki/SWEEPS-04-0.md @@ -0,0 +1,26 @@ +--- +title: "SWEEPS-04" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SWEEPS-04" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:13.670281+00:00" +instance: "kb-cron" +--- + +SWEEPS-04 is an extrasolar planet orbiting the star SWEEPS J175853.92−291120.6 in the constellation Sagittarius approximately 27,710 light years away (based on a distance modulus of 14.1) from the Solar System, making it (along with SWEEPS-11) the most distant exoplanet(s) known. This planet was found in 2006 by the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) program that uses the transit method. +The upper limit on the planet's mass is 3.8 times the mass of Jupiter. The best fit radius is 0.81 times that of Jupiter, but the uncertainty in this value is large, around 12%. It orbits at an average distance of 8,200,000 km (0.055 AU) from the parent star, taking 4.2 days to revolve around it. + + +== See also == +Sagittarius Window Eclipsing Extrasolar Planet Search or SWEEPS +SWEEPS-10 +SWEEPS-11 +List of extrasolar planets + + +== References == + + +== External links == +"SWEEPS-04". Exoplanets. Archived from the original on 2009-11-25. Retrieved 2009-05-22. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SWEEPS-10-0.md b/data/en.wikipedia.org/wiki/SWEEPS-10-0.md new file mode 100644 index 000000000..3a6401632 --- /dev/null +++ b/data/en.wikipedia.org/wiki/SWEEPS-10-0.md @@ -0,0 +1,31 @@ +--- +title: "SWEEPS-10" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SWEEPS-10" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:14.938105+00:00" +instance: "kb-cron" +--- + +SWEEPS-10 is a candidate extrasolar planet that, from June 2007 to August 2011, was the planet candidate with the shortest orbital period yet found, until PSR J1719-1438 b was discovered in 2011 with an even shorter orbit. The planet orbits the star SWEEPS J175902.00−291323.7 located in the Galactic bulge at a distance of approximately 22,000 light years from Earth (based on a distance modulus of 14.1). +It completes an orbit of its star (designated SWEEPS J175902.00−291323.7) in just 10 hours, and is categorized as an ultra-short period planet (USPP). Located only 1.2 million kilometers from its star (roughly three times the distance between the Earth and the Moon), the planet is among the hottest ever detected; its estimated temperature is approximately 1,650 degrees Celsius. "This star-hugging planet must be at least 1.6 times the mass of Jupiter, otherwise the star's gravitational muscle would pull the planet apart," said team leader Kailash Sahu of the Space Telescope Science Institute in Baltimore, Maryland. Such USPPs seem to occur only around dwarf stars. + + +== Host star == +The small star's relatively low temperature allows the planet to exist. "USPPs occur preferentially around normal red dwarf stars that are smaller and cooler than our Sun," Sahu said. + + +== See also == +Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) +SWEEPS-04 +SWEEPS-11 + + +== References == + +Sahu; et al. (2006). "Transiting extrasolar planetary candidates in the Galactic bulge". Nature. 443 (7111): 534–540. arXiv:astro-ph/0610098. Bibcode:2006Natur.443..534S. doi:10.1038/nature05158. PMID 17024085. S2CID 4403395. (web Preprint) + + +== External links == +SWEEPS-10 b at exoplanet.eu Archived 2014-02-02 at the Wayback Machine \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SWEEPS-11-0.md b/data/en.wikipedia.org/wiki/SWEEPS-11-0.md new file mode 100644 index 000000000..2f367e11b --- /dev/null +++ b/data/en.wikipedia.org/wiki/SWEEPS-11-0.md @@ -0,0 +1,25 @@ +--- +title: "SWEEPS-11" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SWEEPS-11" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:16.213011+00:00" +instance: "kb-cron" +--- + +SWEEPS-11 is an extrasolar planet orbiting SWEEPS J175902.67−291153.5 in the constellation Sagittarius, approximately 27,710 light years away from the Solar System (based on a distance modulus of 14.1), making it (along with SWEEPS-04) the most distant exoplanet(s) known. This planet was found in 2006 by the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) program that uses the transit method. +This hot Jupiter has a mass 9.7 times that of Jupiter and a radius of 1.13 times that of Jupiter, but the uncertainty in this value is large, around 21%. The planet orbits at about 1.75 times closer to the star than 51 Pegasi b is to 51 Pegasi, taking only 1.8 days or 43 hours to orbit the star. It is also the most distant planet yet discovered. + + +== See also == +SWEEPS-04 +SWEEPS-10 + + +== References == + + +== External links == + Media related to SWEEPS-11 at Wikimedia Commons +The Extrasolar Planets Encyclopaedia: Notes for planet SWEEPS-11 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SWEEPS_J175853.92−291120.6-0.md b/data/en.wikipedia.org/wiki/SWEEPS_J175853.92−291120.6-0.md new file mode 100644 index 000000000..80cad782f --- /dev/null +++ b/data/en.wikipedia.org/wiki/SWEEPS_J175853.92−291120.6-0.md @@ -0,0 +1,31 @@ +--- +title: "SWEEPS J175853.92−291120.6" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SWEEPS_J175853.92−291120.6" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:12.476935+00:00" +instance: "kb-cron" +--- + +SWEEPS J175853.92-291120.6 is a star located in the constellation Sagittarius at a distance of 27,700 light-years from Earth. At least one planet, SWEEPS-04, is known to orbit the star. +The star has a magnitude of 18 with a mass of 1.24 solar masses and radius of 1.18 solar radii. The designation "SWEEPS J175853.92−291120.6" is named after the project SWEEPS, formally called the Sagittarius Window Eclipsing Extrasolar Planet Search. The project also found its planetary companion. + + +== Planetary system == + +In 2006, a group of astronomers working on the SWEEPS program announced the discovery of the planet SWEEPS-04 in the system. The planet is a gas giant that is close to the parent star at 0.05 AU. The planet is classified as a hot Jupiter due to its proximity to the parent star. The planet was discovered through the transit method. + + +== See also == +List of stars in Sagittarius + + +== References == + + +== External links == + +"SWEEPS-04" (in Russian). планетные системы. Retrieved 26 July 2012. +"Planet SWEEPS-04". Extrasolar Planets Encyclopaedia. Archived from the original on 19 October 2012. Retrieved 26 July 2012. +This article is based on the Russian Wikipedia article, SWEEPS J175853.92-291120.6 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Sagittarius_Window_Eclipsing_Extrasolar_Planet_Search-0.md b/data/en.wikipedia.org/wiki/Sagittarius_Window_Eclipsing_Extrasolar_Planet_Search-0.md index d90135a67..da55f3b61 100644 --- a/data/en.wikipedia.org/wiki/Sagittarius_Window_Eclipsing_Extrasolar_Planet_Search-0.md +++ b/data/en.wikipedia.org/wiki/Sagittarius_Window_Eclipsing_Extrasolar_Planet_Search-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Sagittarius_Window_Eclipsing_Extrasolar_Planet_Search" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T12:58:40.703943+00:00" +date_saved: "2026-05-05T13:15:11.260951+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-0.md b/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-0.md index 0a405756c..42aec94c3 100644 --- a/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-0.md +++ b/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-0.md @@ -4,7 +4,7 @@ chunk: 1/3 source: "https://en.wikipedia.org/wiki/Scaled_Composites_Tier_One" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T12:32:49.494974+00:00" +date_saved: "2026-05-05T13:15:17.800695+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-1.md b/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-1.md index e9429ca48..2cead0e6d 100644 --- a/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-1.md +++ b/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-1.md @@ -4,7 +4,7 @@ chunk: 2/3 source: "https://en.wikipedia.org/wiki/Scaled_Composites_Tier_One" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T12:32:49.494974+00:00" +date_saved: "2026-05-05T13:15:17.800695+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-2.md b/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-2.md index 46b7ae3bb..7bc04f1c0 100644 --- a/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-2.md +++ b/data/en.wikipedia.org/wiki/Scaled_Composites_Tier_One-2.md @@ -4,7 +4,7 @@ chunk: 3/3 source: "https://en.wikipedia.org/wiki/Scaled_Composites_Tier_One" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T12:32:49.494974+00:00" +date_saved: "2026-05-05T13:15:17.800695+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Scaled_Composites_White_Knight-0.md b/data/en.wikipedia.org/wiki/Scaled_Composites_White_Knight-0.md new file mode 100644 index 000000000..fd59eda11 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Scaled_Composites_White_Knight-0.md @@ -0,0 +1,89 @@ +--- +title: "Scaled Composites White Knight" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Scaled_Composites_White_Knight" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:22.623628+00:00" +instance: "kb-cron" +--- + +The Scaled Composites Model 318 White Knight (now also called White Knight One) is a jet-powered carrier aircraft that was used to launch its companion SpaceShipOne, an experimental spaceplane. The White Knight and SpaceShipOne were designed by Burt Rutan and manufactured by Scaled Composites, a private company founded by Rutan in 1982. On three separate flights in 2004, White Knight conducted SpaceShipOne into flight, and SpaceShipOne then performed a sub-orbital spaceflight, becoming the first private craft to reach space. +The White Knight is notable as an example of a mother ship which carried a parasite aircraft into flight, releasing the latter which would then execute a high-altitude flight, or a sub-orbital spaceflight. This flight profile is shared with The High and Mighty One and Balls 8, two modified B-52s which carried the North American X-15 into flight. It is also shared with White Knight Two, a descendant which carries SpaceShipTwo into flight as part of the Virgin Galactic fleet. +Following the SpaceShipOne flights, the White Knight was contracted for drop tests of the Boeing X-37 spaceplane, from June 2005 until April 2006. The White Knight was retired from service in 2014, and is in the inventory of the Flying Heritage Collection. + + +== Design and development == + +The Scaled Composites model number for White Knight is 318. White Knight is registered with the Federal Aviation Administration as N318SL. + +The White Knight carrier airplane was designed around the twin afterburning General Electric J85 engines, which were selected for their availability and low cost. The aircraft was a completely new independent design. White Knight and SpaceShipOne shared the same forward fuselage outer mold line (OML) to reduce development costs and with the original intent to allow for White Knight to act as a flying simulator for training SpaceShipOne pilots. White Knight first flew on August 1, 2002. The flight was aborted shortly after takeoff due to a problem with the outboard wing spoilers. These trailing edge spoilers were designed to greatly increase the glide slope so that the White Knight vehicle could act as a flying simulator for training of SpaceShipOne pilots. During the first flight, the mechanical over-center torque was insufficient to maintain the spoilers in the closed position. The spoilers deployed into the free stream and began a limit cycle forcing the pilot (Mike Melvill) to abort. The spoilers were subsequently disabled completely and the desire for a steep glide slope matching SpaceShipOne was abandoned. +White Knight next flew on August 5, 2002, and this time performed well. Development proceeded over the next few months. With White Knight developed and evaluated, on April 18, 2003, White Knight and SpaceShipOne were presented to the media. +Subsequently, White Knight flew as part of the Tier One program that won the Ansari X Prize on October 4, 2004. +Afterwards, White Knight was used to carry and launch DARPA's experimental X-37 spaceplane for its approach and landing tests in 2005 and 2006. +It was followed up by the White Knight Two, which has a similar but larger design. + + +== SpaceShipOne program == +Flights of White Knight are numbered, starting with flight 1 on August 1, 2002. Flights where SpaceShipOne was carried also get one or two appended letters. An appended "C" indicates that the flight was a captive carry, and "L" indicates that SpaceShipOne was launched. If the flight actually flown differs in category from the intended flight, then two letters are appended, the first giving the intended mission and the second the mission actually performed. + + +== X-37 test program == +White Knight was contracted to perform both captive carry and drop test flights of the DARPA/Boeing X-37. First captive carry flight was on June 21, 2005, and first drop was on April 7, 2006 (the X-37 was subsequently damaged on landing at Edwards Air Force Base). Initially, the flights originated from Mojave, but following the landing incident, the program was moved to Air Force Plant 42 in Palmdale, California, and at least five subsequent flights were made there. + + +== Adaptive Compliant Wing test program == +In late 2006, White Knight flew a seven-flight test program of the adaptive compliant wing developed by FlexSys Inc. with funding by the Air Force Research Laboratory. A laminar flow test article was mounted vertically under White Knight's centerline pylon for the 20-flight-hour research program that tested the flexible wing's aerodynamic characteristics. + + +== Retirement to museum == +In July 2014 White Knight made its final planned flight, arriving at Paine Field in Everett, Washington, to become part of the Flying Heritage Collection. + + +== Specifications == +Data from Scaled CompositesGeneral characteristics +Crew: 3 +Capacity: 8,000 lb (3,600 kg) payload +Wingspan: 83 ft (25 m) +Empty weight: 6,360 lb (2,885 kg) +Max takeoff weight: 18,000 lb (8,165 kg) +Fuel capacity: 6,400 lb (2,900 kg) +Powerplant: 2 × General Electric J85-GE-5 afterburning turbojet, 2,400 lbf (11 kN) thrust each dry, 3,600 lbf (16 kN) with afterburner +Performance + +Service ceiling: 53,000 ft (16,000 m) + + +=== Other features and capabilities === +Carriage and launch of payloads up to 7,000 lb (3,200 kg) +Altitude capability above 53,000 ft +Large, three-place cabin (60 in (1,524 mm) diameter outside, 59 in (1,499 mm) inside) +Sea level cabin qualified for unlimited altitude +ECS scrubs CO2, removes humidity and defogs windows +Two crew doors with dual seals and dual-pane windows +Manual flight controls with three-axis electric trim +Avionics include INS-GPS navigator, flight-director, flight test data (recording and T/M), air-data, vehicle health monitoring, backup flight instruments, and video system +The 82 ft (25 m) wing can be extended to 93 ft (28 m) for increased climb capability +Super-effective, pneumatic speed brakes allow steep descent with L/D < 4.5 +Hydraulic wheel brakes and nose-gear steering +Pneumatic main gear retraction +Dual-bus electrical power system +Cockpit allows single-pilot operation (VMC-day conditions only) + + +== See also == +Flying aircraft carrier +Conroy Virtus +Lockheed twin-body C-5 Shuttle Carrier proposal +Scaled Composites Proteus +Scaled Composites Stratolaunch + + +== References == + + +== External links == + +Scaled Composites' Tier One website Archived 2018-04-07 at the Wayback Machine +White Knight's FAA registration +WhiteKnight to launch X-37 test flights \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-0.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-0.md new file mode 100644 index 000000000..d8c7d442a --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-0.md @@ -0,0 +1,31 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 1/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +The search for extraterrestrial intelligence (usually shortened as SETI) is the diverse efforts and scientific projects intended to detect extraterrestrial signals, or any evidence of intelligent life beyond Earth. +Researchers use methods such as monitoring electromagnetic radiation, searching for optical signals, and investigating potential extraterrestrial artifacts for any signs of transmission from civilizations present on other planets. Some initiatives have also attempted to send messages to hypothetical alien civilizations, such as NASA's Golden Record. +Modern SETI research began in the early 20th century after the advent of radio, expanding with projects like Project Ozma, the Wow! signal detection, and the Breakthrough Listen initiative; a $100 million, 10-year attempt to detect signals from nearby stars, announced in 2015 by Stephen Hawking and Yuri Milner. Since the 1980s, international efforts have been ongoing, with community led projects such as SETI@home and Project Argus, engaging in analyzing data. While SETI remains a respected scientific field, it often gets compared to conspiracy theory, UFO research, bringing unwarranted skepticism from the public, despite its reliance on rigorous scientific methods and verifiable data and research. Similar studies on unidentified aerial phenomena (UAP) such as Avi Loeb's Galileo Project have brought further attention to SETI research. +Despite decades of searching, no confirmed evidence of alien intelligence has been found, bringing criticism onto SETI for being 'overly hopeful'. Critics argue that SETI is speculative and unfalsifiable, while supporters see it as a crucial step in addressing the Fermi paradox and understanding extraterrestrial technosignature. + +== History == + +=== Early work === +There have been many earlier searches for extraterrestrial intelligence within the Solar System. In 1896, Nikola Tesla suggested that an extreme version of his wireless electrical transmission system could be used to contact beings on Mars. In 1899, while conducting experiments at his Colorado Springs experimental station, he thought he had detected a signal from Mars since an odd repetitive static signal seemed to cut off when Mars set in the night sky. Analysis of Tesla's research has led to a range of explanations including: + +Tesla simply misunderstood the new technology he was working with, +that he may have been observing signals from Marconi's European radio experiments, +and even speculation that he could have picked up naturally occurring radio noise caused by a moon of Jupiter (Io) moving through the magnetosphere of Jupiter. +In the early 1900s, Guglielmo Marconi, Lord Kelvin and David Peck Todd also stated their belief that radio could be used to contact Martians, with Marconi stating that his stations had also picked up potential Martian signals. +On August 21–23, 1924, Mars entered an opposition closer to Earth than at any time in the century before or the next 80 years. In the United States, a "National Radio Silence Day" was promoted during a 36-hour period from August 21–23, with all radios quiet for five minutes on the hour, every hour. At the United States Naval Observatory, a radio receiver was lifted 3 kilometres (1.9 miles) above the ground in a dirigible tuned to a wavelength between 8 and 9 km, using a "radio-camera" developed by Amherst College and Charles Francis Jenkins. The program was led by David Peck Todd with the military assistance of Admiral Edward W. Eberle (Chief of Naval Operations), with William F. Friedman (chief cryptographer of the United States Army), assigned to translate any potential Martian messages. +A 1959 paper by Philip Morrison and Giuseppe Cocconi first pointed out the possibility of searching the microwave spectrum. It proposed frequencies and a set of initial targets. +In 1960, Cornell University astronomer Frank Drake performed the first modern SETI experiment, named "Project Ozma" after the Queen of Oz in L. Frank Baum's fantasy books. Drake used a radio telescope 26 metres (85 ft) in diameter at Green Bank, West Virginia, to examine the stars Tau Ceti and Epsilon Eridani near the 1.420 gigahertz marker frequency, a region of the radio spectrum dubbed the "water hole" due to its proximity to the hydrogen and hydroxyl radical spectral lines. A 400 kilohertz band around the marker frequency was scanned using a single-channel receiver with a bandwidth of 100 hertz. He found nothing of interest. +Soviet scientists took a strong interest in SETI during the 1960s and performed a number of searches with omnidirectional antennas in the hope of picking up powerful radio signals. Soviet astronomer Iosif Shklovsky wrote the pioneering book in the field, Universe, Life, Intelligence (1962), which was expanded upon by American astronomer Carl Sagan as the best-selling book Intelligent Life in the Universe (1966). +In the March 1955 issue of Scientific American, John D. Kraus described an idea to scan the cosmos for natural radio signals using a flat-plane radio telescope equipped with a parabolic reflector. Within two years, his concept was approved for construction by Ohio State University. With a total of US$71,000 (equivalent to $813,892 in 2025) +in grants from the National Science Foundation, construction began on an 8-hectare (20-acre) plot in Delaware, Ohio. This Ohio State University Radio Observatory telescope was called "Big Ear". Later, it began the world's first continuous SETI program, called the Ohio State University SETI program. +In 1971, NASA funded a SETI study that involved Drake, Barney Oliver of Hewlett-Packard Laboratories, and others. The resulting report proposed the construction of an Earth-based radio telescope array with 1,500 dishes known as "Project Cyclops". The price tag for the Cyclops array was US$10 billion. Cyclops was not built, but the report formed the basis of much SETI work that followed. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-1.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-1.md new file mode 100644 index 000000000..0728fc3f3 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-1.md @@ -0,0 +1,20 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 2/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +The Ohio State SETI program gained fame on August 15, 1977, when Jerry Ehman, a project volunteer, witnessed a startlingly strong signal received by the telescope. He quickly circled the indication on a printout and scribbled the exclamation "Wow!" in the margin. Dubbed the Wow! signal, it is considered by some to be the best candidate for a radio signal from an artificial, extraterrestrial source ever discovered, but it has not been detected again in several additional searches. +On 24 May 2023, a test extraterrestrial signal, in the form of a "coded radio signal from Mars", was transmitted to radio telescopes on Earth, according to a report in The New York Times. + +=== Sentinel, META, and BETA === +In 1980, Carl Sagan, Bruce Murray, and Louis Friedman founded the U.S. Planetary Society, partly as a vehicle for SETI studies. +In the early 1980s, Harvard University physicist Paul Horowitz took the next step and proposed the design of a spectrum analyzer specifically intended to search for SETI transmissions. Traditional desktop spectrum analyzers were of little use for this job, as they sampled frequencies using banks of analog filters and so were restricted in the number of channels they could acquire. However, modern integrated-circuit digital signal processing (DSP) technology could be used to build autocorrelation receivers to check far more channels. This work led in 1981 to a portable spectrum analyzer named "Suitcase SETI" that had a capacity of 131,000 narrow band channels. After field tests that lasted into 1982, Suitcase SETI was put into use in 1983 with the 26-meter (85 ft) Harvard/Smithsonian radio telescope at Oak Ridge Observatory in Harvard, Massachusetts. This project was named "Sentinel" and continued into 1985. +Even 131,000 channels were not enough to search the sky in detail at a fast rate, so Suitcase SETI was followed in 1985 by Project "META", for "Megachannel Extra-Terrestrial Assay". The META spectrum analyzer had a capacity of 8.4 million channels and a channel resolution of 0.05 hertz. An important feature of META was its use of frequency Doppler shift to distinguish between signals of terrestrial and extraterrestrial origin. The project was led by Horowitz with the help of the Planetary Society, and was partly funded by movie maker Steven Spielberg. A second such effort, META II, was begun in Argentina in 1990, to search the southern sky, receiving an equipment upgrade in 1996–1997. +The follow-on to META was named "BETA", for "Billion-channel Extraterrestrial Assay", and it commenced observation on October 30, 1995. The heart of BETA's processing capability consisted of 63 dedicated fast Fourier transform (FFT) engines, each capable of performing a 222-point complex FFTs in two seconds, and 21 general-purpose personal computers equipped with custom digital signal processing boards. This allowed BETA to receive 250 million simultaneous channels with a resolution of 0.5 hertz per channel. It scanned through the microwave spectrum from 1.400 to 1.720 gigahertz in eight hops, with two seconds of observation per hop. An important capability of the BETA search was rapid and automatic re-observation of candidate signals, achieved by observing the sky with two adjacent beams, one slightly to the east and the other slightly to the west. A successful candidate signal would first transit the east beam, and then the west beam and do so with a speed consistent with Earth's sidereal rotation rate. A third receiver observed the horizon to veto signals of obvious terrestrial origin. On March 23, 1999, the 26-meter radio telescope on which Sentinel, META and BETA were based was blown over by strong winds and seriously damaged. This forced the BETA project to cease operation. + +=== MOP and Project Phoenix === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-10.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-10.md new file mode 100644 index 000000000..ba2e2f3e1 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-10.md @@ -0,0 +1,23 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 11/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +=== Realized interstellar radio message projects === +In November 1974, a largely symbolic attempt was made at the Arecibo Observatory to send a message to other worlds. Known as the Arecibo Message, it was sent towards the globular cluster M13, which is 25,000 light-years from Earth. Further IRMs Cosmic Call, Teen Age Message, Cosmic Call 2, and A Message From Earth were transmitted in 1999, 2001, 2003 and 2008 from the Evpatoria Planetary Radar. + +=== Debate === + +Whether or not to attempt to contact extraterrestrials has attracted significant academic debate in the fields of space ethics and space policy. Physicist Stephen Hawking, in his book A Brief History of Time, suggests that "alerting" extraterrestrial intelligences to our existence is foolhardy, citing humankind's history of treating its own kind harshly in meetings of civilizations with a significant technology gap, e.g., the extermination of Tasmanian aborigines. He suggests, in view of this history, that we "lay low". In one response to Hawking, in September 2016, astronomer Seth Shostak sought to allay such concerns. Astronomer Jill Tarter also disagrees with Hawking, arguing that aliens developed and long-lived enough to communicate and travel across interstellar distances would have evolved a cooperative and less violent intelligence. She however thinks it is too soon for humans to attempt active SETI and that humans should be more advanced technologically first but keep listening in the meantime. + +== Criticism == + +As various SETI projects have progressed, some have criticized early claims by researchers as being too "euphoric". For example, Peter Schenkel, while remaining a supporter of SETI projects, wrote in 2006 that: + +[i]n light of new findings and insights, it seems appropriate to put excessive euphoria to rest and to take a more down-to-earth view [...] We should quietly admit that the early estimates—that there may be a million, a hundred thousand, or ten thousand advanced extraterrestrial civilizations in our galaxy—may no longer be tenable. +Critics claim that the existence of extraterrestrial intelligence has no good Popperian criteria for falsifiability, as explained in a 2009 editorial in Nature, which said: \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-11.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-11.md new file mode 100644 index 000000000..a928600dc --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-11.md @@ -0,0 +1,20 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 12/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +Seti... has always sat at the edge of mainstream astronomy. This is partly because, no matter how scientifically rigorous its practitioners try to be, SETI can't escape an association with UFO believers and other such crackpots. But it is also because SETI is arguably not a falsifiable experiment. Regardless of how exhaustively the Galaxy is searched, the null result of radio silence doesn't rule out the existence of alien civilizations. It means only that those civilizations might not be using radio to communicate. +Nature added that SETI was "marked by a hope, bordering on faith" that aliens were aiming signals at us, that a hypothetical alien SETI project looking at Earth with "similar faith" would be "sorely disappointed", despite our many untargeted radar and TV signals, and our few targeted Active SETI radio signals denounced by those fearing aliens, and that it had difficulties attracting even sympathetic working scientists and government funding because it was "an effort so likely to turn up nothing". +However, Nature also added, "Nonetheless, a small SETI effort is well worth supporting, especially given the enormous implications if it did succeed" and that "happily, a handful of wealthy technologists and other private donors have proved willing to provide that support". +Supporters of the Rare Earth Hypothesis argue that advanced lifeforms are likely to be very rare, and that, if that is so, then SETI efforts will be futile. However, the Rare Earth Hypothesis itself faces many criticisms. +In 1993, Roy Mash stated that "Arguments favoring the existence of extraterrestrial intelligence nearly always contain an overt appeal to big numbers, often combined with a covert reliance on generalization from a single instance" and concluded that "the dispute between believers and skeptics is seen to boil down to a conflict of intuitions which can barely be engaged, let alone resolved, given our present state of knowledge". In response, in 2012, Milan M. Ćirković, then research professor at the Astronomical Observatory of Belgrade and a research associate of the Future of Humanity Institute at the University of Oxford, said that Mash was unrealistically over-reliant on excessive abstraction that ignored the empirical information available to modern SETI researchers. +George Basalla, Emeritus Professor of History at the University of Delaware, is a critic of SETI who argued in 2006 that "extraterrestrials discussed by scientists are as imaginary as the spirits and gods of religion or myth", and was in turn criticized by Milan M. Ćirković for, among other things, being unable to distinguish between "SETI believers" and "scientists engaged in SETI", who are often sceptical (especially about quick detection), such as Freeman Dyson and, at least in their later years, Iosif Shklovsky and Sebastian von Hoerner, and for ignoring the difference between the knowledge underlying the arguments of modern scientists and those of ancient Greek thinkers. +Massimo Pigliucci, Professor of Philosophy at CUNY – City College, asked in 2010 whether SETI is "uncomfortably close to the status of pseudoscience" due to the lack of any clear point at which negative results cause the hypothesis of Extraterrestrial Intelligence to be abandoned, before eventually concluding that SETI is "almost-science", which is described by Milan M. Ćirković as Pigliucci putting SETI in "the illustrious company of string theory, interpretations of quantum mechanics, evolutionary psychology and history (of the 'synthetic' kind done recently by Jared Diamond)", while adding that his justification for doing so with SETI "is weak, outdated, and reflecting particular philosophical prejudices similar to the ones described above in Mash and Basalla". +Richard Carrigan, a particle physicist at the Fermi National Accelerator Laboratory near Chicago, Illinois, suggested that passive SETI could also be dangerous and that a signal released onto the Internet could act as a computer virus. Computer security expert Bruce Schneier dismissed this possibility as a "bizarre movie-plot threat". +In an attempt to present the search for extraterrestrial intelligence within a broader historical context, Lewis White Beck at the University of Rochester traced its development within the works of several philosophers of the Western tradition including: Lucretius, Plutarch, Aristotle, Copernicus, Immanuel Kant, John Wilkins, Charles Darwin and Karl Marx. His analysis suggests that even in modern times, humanity's "objective quest" can be clouded by ancient archetypal paradigms which are derived from firmly rooted religious, philosophical and existential belief systems. Citing the difficulties associated with an anthropomorphic paradigm of extraterrestrial intelligence, Beck noted that, "Myth, religion, and now science-fiction...are commentaries on the human condition. I believe even responsible scientific speculation... in search for other life are the peculiarly modern equivalent of angelology and Utopia or of demonology and apocalypse." +Beck also raises epistemological doubts as to whether a "successful" detection of modulated radio signa from the heavens could be deciphered at all by noting that "in the absence of collateral information, the necessary but not sufficient condition for knowing that something is a message is to know what it says. Since the necessary collateral information will be lacking, we must guess that it is a message, guess what it says, and then try to see if the signal can convey that message." Complicating matters further are the difficulties associated with identifying a rational vocabulary of denotive words which might be contained within such a message. Citing the work of Peter Winch, Beck notes that humanity need not succumb to despair, however, for "to study another way of life is necessarily to seek to extend our own-- not simply to bring the other way within the already existing boundaries of our own..." Beck therefore concludes optimistically by suggesting that even if a world-wide sharing of radio observatories fails to detect the presence of extraterrestrial intelligence, it may prove invaluable to identifying superior enlightened intellectual paradigms for human life on our own Earth. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-12.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-12.md new file mode 100644 index 000000000..86c281e42 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-12.md @@ -0,0 +1,44 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 13/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +=== Ufology === + Ufologist Stanton Friedman has often criticized SETI researchers for, among other reasons, what he sees as their unscientific criticisms of ufology, but, unlike SETI, ufology has generally not been embraced by academia as a scientific field of study, and it is usually characterized as a partial or total pseudoscience. In a 2016 interview, Jill Tarter pointed out that it is still a misconception that SETI and UFOs are related. She states, "SETI uses the tools of the astronomer to attempt to find evidence of somebody else's technology coming from a great distance. If we ever claim detection of a signal, we will provide evidence and data that can be independently confirmed. UFOs—none of the above." The Galileo Project headed by Harvard astronomer Avi Loeb is one of the few scientific efforts to study UFOs or UAPs. Loeb criticized that the study of UAP is often dismissed and not sufficiently studied by scientists and should shift from "occupying the talking points of national security administrators and politicians" to the realm of science. The Galileo Project's position after the publication of the 2021 UFO Report by the U.S. Intelligence community is that the scientific community needs to "systematically, scientifically and transparently look for potential evidence of extraterrestrial technological equipment". + +== See also == + +== References == + +== Further reading == + +Campbell, John B. (2006). "Archaeology and direct imaging of exoplanets" (PDF). In C. Aime & F. Vakili (ed.). Proceedings of the International Astronomical Union. Cambridge University Press. pp. 247 ff. ISBN 978-0-521-85607-2. Archived from the original (PDF) on 2009-03-26. +Carlotto, Mark J. (2007). "Detecting Patterns of a Technological Intelligence in Remotely Sensed Imagery" (PDF). Journal of the British Interplanetary Society. 60: 28–39. Bibcode:2007JBIS...60...28C. Archived from the original (PDF) on 2016-09-09. Retrieved 2009-03-03. +Catran, Jack (1980). Is There Intelligent Life on Earth?. Lidiraven Books. ISBN 978-0-9361-6229-4. +Ćirković, Milan M. (2012). The Astrobiological Landscape: Philosophical Foundations of the Study of Cosmic Life. Cambridge Astrobiology. Cambridge University Press. ISBN 978-0-521-19775-5. ISSN 1759-3247. +Cooper, Keith (2019). The Contact Paradox: Challenging Our Assumptions in the Search for Extraterrestrial Intelligence. Bloomsbury Publishing. ISBN 978-1-4729-6044-3. +DeVito, Carl L. (2013). Science, Seti, and Mathematics. Berghahn Books. ISBN 978-1-78238-070-2. +Maccone, Claudio (2022). Evo-SETI: Life Evolution Statistics on Earth and Exoplanets. Springer International Publishing. ISBN 978-3-030-51933-9. +McConnell, Brian; Chuck Toporek (2001). Beyond Contact: A Guide to SETI and Communicating with Alien Civilizations. O'Reilly. ISBN 978-0-596-00037-0. +Phillip Morrison, John Billingham, & John Wolfe: The search for extraterrestrial intelligence—SETI. NASA SP, Washington 1977 +Oberhaus, Daniel (2019). Extraterrestrial Languages. The MIT Press. ISBN 978-0-262-04306-9. +Roush, Wade (2020). Extraterrestrials. MIT Press. ISBN 978-0-262-53843-5. +David W. Swift: Seti Pioneers: Scientists Talk about Their Search for Extraterrestrial Intelligence. University of Arizona Press, Tucson, Arizona, 1993, ISBN 0-8165-1119-5 +Frank White: The Seti Factor: How the Search for Extraterrestrial Intelligence Is Changing Our View of the Universe and Ourselves. Walker & Company, New York 1990, ISBN 978-0-8027-1105-2 +Jon Willis (2016). All These Worlds Are Yours: The Scientific Search for Alien Life. Yale University Press. ISBN 978-0-300-20869-6. + +== External links == + +SETI Institute website +Harvard University SETI Program Archived 2011-08-10 at the Wayback Machine +University of California, Berkeley SETI Program +Project Dorothy, a Worldwide Joint SETI Observation to Commemorate the 50th Anniversary of Project OZMA +"SETI: Astronomy as a Contact Sport - A conversation with Jill Tarter". Ideas Roadshow. April 19, 2013. +The Rio Scale Archived 2015-09-14 at the Wayback Machine, a scale for rating SETI announcements +2012 Interview of SETI Pioneer Frank Drake by astronomer Andrew Fraknoi +Now dark SETI Net station archives (www.seti.net) \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-2.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-2.md new file mode 100644 index 000000000..46e6b03ff --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-2.md @@ -0,0 +1,19 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 3/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +In 1978, the NASA SETI program had been heavily criticized by Senator William Proxmire, and funding for SETI research was removed from the NASA budget by Congress in 1981; however, funding was restored in 1982, after Carl Sagan talked with Proxmire and convinced him of the program's value. In 1992, the U.S. government funded an operational SETI program, in the form of the NASA Microwave Observing Program (MOP). MOP was planned as a long-term effort to conduct a general survey of the sky and also carry out targeted searches of 800 specific nearby stars. MOP was to be performed by radio antennas associated with the NASA Deep Space Network, as well as the 140-foot (43 m) radio telescope of the National Radio Astronomy Observatory at Green Bank, West Virginia and the 1,000-foot (300 m) radio telescope at the Arecibo Observatory in Puerto Rico. The signals were to be analyzed by spectrum analyzers, each with a capacity of 15 million channels. These spectrum analyzers could be grouped together to obtain greater capacity. Those used in the targeted search had a bandwidth of 1 hertz per channel, while those used in the sky survey had a bandwidth of 30 hertz per channel. +MOP drew the attention of the United States Congress, where the program met opposition and canceled one year after its start. SETI advocates continued without government funding, and in 1995 the nonprofit SETI Institute of Mountain View, California resurrected the MOP program under the name of Project "Phoenix", backed by private sources of funding. In 2012 it cost around $2 million per year to maintain SETI research at the SETI Institute and around 10 times that to support different SETI activities globally. Project Phoenix, under the direction of Jill Tarter, was a continuation of the targeted search program from MOP and studied roughly 1,000 nearby Sun-like stars until approximately 2015. From 1995 through March 2004, Phoenix conducted observations at the 64-meter (210 ft) Parkes radio telescope in Australia, the 140-foot (43 m) radio telescope of the National Radio Astronomy Observatory in Green Bank, West Virginia, and the 1,000-foot (300 m) radio telescope at the Arecibo Observatory in Puerto Rico. The project observed the equivalent of 800 stars over the available channels in the frequency range from 1200 to 3000 MHz. The search was sensitive enough to pick up transmitters with 1 GW EIRP to a distance of about 200 light-years. + +== Ongoing radio searches == + +Many radio frequencies penetrate Earth's atmosphere quite well, and this led to radio telescopes that investigate the cosmos using large radio antennas. Furthermore, human endeavors emit considerable electromagnetic radiation as a byproduct of communications such as television and radio. These signals would be easy to recognize as artificial due to their repetitive nature and narrow bandwidths. Earth has been sending radio waves from broadcasts into space for over 100 years. These signals have reached over 1,000 stars, most notably Vega, Aldebaran, Barnard's Star, Sirius, and Proxima Centauri. If intelligent alien life exists on any planet orbiting these nearby stars, these signals could be heard and deciphered, even though some of the signal is garbled by the Earth's ionosphere. +Many international radio telescopes are currently being used for radio SETI searches, including the Low Frequency Array (LOFAR) in Europe, the Murchison Widefield Array (MWA) in Australia, and the Lovell Telescope in the United Kingdom. + +=== Allen Telescope Array === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-3.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-3.md new file mode 100644 index 000000000..006ff9d07 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-3.md @@ -0,0 +1,29 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 4/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +The SETI Institute collaborated with the Radio Astronomy Laboratory at the Berkeley SETI Research Center to develop a specialized radio telescope array for SETI studies, similar to a mini-cyclops array. Formerly known as the One Hectare Telescope (1HT), the concept was renamed the "Allen Telescope Array" (ATA) after the project's benefactor, Paul Allen. Its sensitivity is designed to be equivalent to a single large dish more than 100 meters in diameter, if fully completed. Presently, the array has 42 operational dishes at the Hat Creek Radio Observatory in rural northern California. +The full array (ATA-350) is planned to consist of 350 or more offset-Gregorian radio dishes, each 6.1 meters (20 feet) in diameter. These dishes are the largest producible with commercially available satellite television dish technology. The ATA was planned for a 2007 completion date, at a cost of US$25 million. The SETI Institute provided money for building the ATA while University of California, Berkeley designed the telescope and provided operational funding. The first portion of the array (ATA-42) became operational in October 2007 with 42 antennas. The DSP system planned for ATA-350 is extremely ambitious. Completion of the full 350 element array will depend on funding and the technical results from ATA-42. +ATA-42 (ATA) is designed to allow multiple observers simultaneous access to the interferometer output at the same time. Typically, the ATA snapshot imager (used for astronomical surveys and SETI) is run in parallel with a beamforming system (used primarily for SETI). ATA also supports observations in multiple synthesized pencil beams at once, through a technique known as "multibeaming". Multibeaming provides an effective filter for identifying false positives in SETI, since a very distant transmitter must appear at only one point on the sky. +SETI Institute's Center for SETI Research (CSR) uses ATA in the search for extraterrestrial intelligence, observing 12 hours a day, 7 days a week. From 2007 to 2015, ATA identified hundreds of millions of technological signals. So far, all these signals have been assigned the status of noise or radio frequency interference because a) they appear to be generated by satellites or Earth-based transmitters, or b) they disappeared before the threshold time limit of ~1 hour. Researchers in CSR are working on ways to reduce the threshold time limit, and to expand ATA's capabilities for detection of signals that may have embedded messages. +Berkeley astronomers used the ATA to pursue several science topics, some of which might have transient SETI signals, until 2011, when the collaboration between the University of California, Berkeley and the SETI Institute was terminated. +CNET published an article and pictures about the Allen Telescope Array (ATA) on December 12, 2008. +In April 2011, the ATA entered an 8-month "hibernation" due to funding shortfalls. Regular operation of the ATA resumed on December 5, 2011. +In 2012, the ATA was revitalized with a $3.6 million donation by Franklin Antonio, co-founder and Chief Scientist of QUALCOMM Incorporated. This gift supported upgrades of all the receivers on the ATA dishes to have (2× to 10× over the range 1–8 GHz) greater sensitivity than before and supporting observations over a wider frequency range from 1–18 GHz, though initially the radio frequency electronics only go to 12 GHz. As of July 2013, the first of these receivers was installed and proven, with full installation on all 42 antennas being expected for June 2017. ATA is well suited to the search for extraterrestrial intelligence (SETI) and to discovery of astronomical radio sources, such as heretofore unexplained non-repeating, possibly extragalactic, pulses known as fast radio bursts or FRBs. + +=== SERENDIP === + +SERENDIP (Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations) is a SETI program launched in 1979 by the Berkeley SETI Research Center. SERENDIP takes advantage of ongoing "mainstream" radio telescope observations as a "piggy-back" or "commensal" program, using large radio telescopes including the NRAO 90m telescope at Green Bank and, formerly, the Arecibo 305m telescope. Rather than having its own observation program, SERENDIP analyzes deep space radio telescope data that it obtains while other astronomers are using the telescopes. The most recently deployed SERENDIP spectrometer, SERENDIP VI, was installed at both the Arecibo Telescope and the Green Bank Telescope in 2014–2015. + +=== Breakthrough Listen === +Breakthrough Listen is a ten-year initiative with $100 million funding begun in July 2015 to actively search for intelligent extraterrestrial communications in the universe, in a substantially expanded way, using resources that had not previously been extensively used for the purpose. It has been described as the most comprehensive search for alien communications to date. The science program for Breakthrough Listen is based at Berkeley SETI Research Center, located in the Astronomy Department at the University of California, Berkeley. +Announced in July 2015, the project is observing for thousands of hours every year on two major radio telescopes, the Green Bank Observatory in West Virginia, and the Parkes Observatory in Australia. Previously, only about 24 to 36 hours of telescope time per year were used in the search for alien life. Furthermore, the Automated Planet Finder at Lick Observatory is searching for optical signals coming from laser transmissions. The massive data rates from the radio telescopes (24 GB/s at Green Bank) necessitated the construction of dedicated hardware at the telescopes to perform the bulk of the analysis. Some of the data are also analyzed by volunteers in the SETI@home volunteer computing network. Founder of modern SETI Frank Drake was one of the scientists on the project's advisory committee. +In October 2019, Breakthrough Listen started a collaboration with scientists from the TESS team (Transiting Exoplanet Survey Satellite) to look for signs of advanced extraterrestrial life. Thousands of new planets found by TESS will be scanned for technosignatures by Breakthrough Listen partner facilities across the globe. Data from TESS monitoring of stars will also be searched for anomalies. + +=== FAST === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-4.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-4.md new file mode 100644 index 000000000..5dc839827 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-4.md @@ -0,0 +1,29 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 5/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +China's 500 meter Aperture Spherical Telescope (FAST) lists detecting interstellar communication signals as part of its science mission. It is funded by the National Development and Reform Commission (NDRC) and managed by the National Astronomical observatories (NAOC) of the Chinese Academy of Sciences (CAS). FAST is the first radio observatory built with SETI as a core scientific goal. FAST consists of a fixed 500 m (1,600 ft) diameter spherical dish constructed in a natural depression sinkhole caused by karst processes in the region. It is the world's largest filled-aperture radio telescope. +According to its website, FAST can search to 28 light-years, and is able to reach 1,400 stars. If the transmitter's radiated power were to be increased to 1,000,000 MW, FAST would be able to reach one million stars. This is compared to the former Arecibo 305 meter telescope detection distance of 18 light-years. +On 14 June 2022, astronomers, working with China's FAST telescope, reported the possibility of having detected artificial (presumably alien) signals, but cautioned that further studies were required to determine if a natural radio interference may be the source. More recently, on 18 June 2022, Dan Werthimer, chief scientist for several SETI-related projects, reportedly noted, "These signals are from radio interference; they are due to radio pollution from earthlings, not from E.T.". + +=== UCLA === +Since 2016, University of California Los Angeles (UCLA) undergraduate and graduate students have been participating in radio searches for technosignatures with the Green Bank Telescope. Targets include the Kepler field, TRAPPIST-1, and solar-type stars. The search is sensitive to Arecibo-class transmitters located within 420 light years of Earth and to transmitters that are 1,000 times more powerful than Arecibo located within 13,000 light years of Earth. + +== Community SETI projects == + +=== SETI@home === + +The SETI@home project used volunteer computing to analyze signals acquired by the SERENDIP project. +SETI@home was conceived by David Gedye along with Craig Kasnoff and is a popular volunteer computing project that was launched by the Berkeley SETI Research Center at the University of California, Berkeley, in May 1999. It was originally funded by The Planetary Society and Paramount Pictures, and later by the state of California. The project is run by director David P. Anderson and chief scientist Dan Werthimer. Any individual could become involved with SETI research by downloading the Berkeley Open Infrastructure for Network Computing (BOINC) software program, attaching to the SETI@home project, and allowing the program to run as a background process that uses idle computer power. The SETI@home program itself ran signal analysis on a "work unit" of data recorded from the central 2.5 MHz wide band of the SERENDIP IV instrument. After computation on the work unit was complete, the results were then automatically reported back to SETI@home servers at University of California, Berkeley. By June 28, 2009, the SETI@home project had over 180,000 active participants volunteering a total of over 290,000 computers. These computers gave SETI@home an average computational power of 617 teraFLOPS. In 2004, radio source SHGb02+14a set off speculation in the media that a signal had been detected but researchers noted the frequency drifted rapidly and the detection on three SETI@home computers fell within random chance. +By 2010, after 10 years of data collection, SETI@home had listened to that one frequency at every point of over 67 percent of the sky observable from Arecibo with at least three scans (out of the goal of nine scans), which covers about 20 percent of the full celestial sphere. On March 31, 2020, with 91,454 active users, the project stopped sending out new work to SETI@home users, bringing this particular SETI effort to an indefinite hiatus. + +=== SETI Net === +SETI Network was the only fully operational private search system. The SETI Net station consisted of off-the-shelf, consumer-grade electronics to minimize cost and to allow this design to be replicated as simply as possible. It had a 3-meter parabolic antenna that could be directed in azimuth and elevation, an LNA that covered 100 MHz of the 1420 MHz spectrum, a receiver to reproduce the wideband audio, and a standard personal computer as the control device and for deploying the detection algorithms. The antenna could be pointed and locked to one sky location in Ra and DEC which enabling the system to integrate on it for long periods. The Wow! signal area was monitored for many long periods. All search data was collected and is available on the Internet archive. +SETI Net started operation in the early 1980s as a way to learn about the science of the search, and developed several software packages for the amateur SETI community. It provided an astronomical clock, a file manager to keep track of SETI data files, a spectrum analyzer optimized for amateur SETI, remote control of the station from the Internet, and other packages. +SETI Net went dark and was decommissioned on 2021-12-04. The collected data is available on their website. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-5.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-5.md new file mode 100644 index 000000000..475177535 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-5.md @@ -0,0 +1,14 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 6/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +=== The SETI League and Project Argus === +Founded in 1994 in response to the United States Congress cancellation of the NASA SETI program, The SETI League, Incorporated is a membership-supported nonprofit organization with 1,500 members in 62 countries. This grass-roots alliance of amateur and professional radio astronomers is headed by executive director emeritus H. Paul Shuch, the engineer credited with developing the world's first commercial home satellite TV receiver. Many SETI League members are licensed radio amateurs and microwave experimenters. Others are digital signal processing experts and computer enthusiasts. +The SETI League pioneered the conversion of backyard satellite TV dishes 3 to 5 m (10–16 ft) in diameter into research-grade radio telescopes of modest sensitivity. The organization concentrates on coordinating a global network of small, amateur-built radio telescopes under Project Argus, an all-sky survey seeking to achieve real-time coverage of the entire sky. Project Argus was conceived as a continuation of the all-sky survey component of the late NASA SETI program (the targeted search having been continued by the SETI Institute's Project Phoenix). There are currently 143 Project Argus radio telescopes operating in 27 countries. Project Argus instruments typically exhibit sensitivity on the order of 10−23 Watts/square metre, or roughly equivalent to that achieved by the Ohio State University Big Ear radio telescope in 1977, when it detected the landmark "Wow!" candidate signal. +The name "Argus" derives from the mythical Greek guard-beast who had 100 eyes, and could see in all directions at once. In the SETI context, the name has been used for radio telescopes in fiction (Arthur C. Clarke, "Imperial Earth"; Carl Sagan, "Contact"), was the name initially used for the NASA study ultimately known as "Cyclops," and is the name given to an omnidirectional radio telescope design being developed at the Ohio State University. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-6.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-6.md new file mode 100644 index 000000000..c9226fe4c --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-6.md @@ -0,0 +1,27 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 7/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +== Optical experiments == +While most SETI sky searches have studied the radio spectrum, some SETI researchers have considered the possibility that alien civilizations might be using powerful lasers for interstellar communications at optical wavelengths. The idea was first suggested by R. N. Schwartz and Charles Hard Townes in a 1961 paper published in the journal Nature titled "Interstellar and Interplanetary Communication by Optical Masers". However, the 1971 Cyclops study discounted the possibility of optical SETI, reasoning that construction of a laser system that could outshine the bright central star of a remote star system would be too difficult. In 1983, Townes published a detailed study of the idea in the United States journal Proceedings of the National Academy of Sciences, which was met with interest by the SETI community. +There are two problems with optical SETI. The first problem is that lasers are highly "monochromatic", that is, they emit light only on one frequency, making it troublesome to figure out what frequency to look for. However, emitting light in narrow pulses results in a broad spectrum of emission; the spread in frequency becomes higher as the pulse width becomes narrower, making it easier to detect an emission. +The other problem is that while radio transmissions can be broadcast in all directions, lasers are highly directional. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from greater distances, but the extraterrestrial laser signals would need to be transmitted in the direction of Earth in order to be detected. +Optical SETI supporters have conducted paper studies of the effectiveness of using contemporary high-energy lasers and a ten-meter diameter mirror as an interstellar beacon. The analysis shows that an infrared pulse from a laser, focused into a narrow beam by such a mirror, would appear thousands of times brighter than the Sun to a distant civilization in the beam's line of fire. The Cyclops study proved incorrect in suggesting a laser beam would be inherently hard to see. +Such a system could be made to automatically steer itself through a target list, sending a pulse to each target at a constant rate. This would allow targeting of all Sun-like stars within a distance of 100 light-years. The studies have also described an automatic laser pulse detector system with a low-cost, two-meter mirror made of carbon composite materials, focusing on an array of light detectors. This automatic detector system could perform sky surveys to detect laser flashes from civilizations attempting contact. +Several optical SETI experiments are now in progress. A Harvard-Smithsonian group that includes Paul Horowitz designed a laser detector and mounted it on Harvard's 155-centimeter (61-inch) optical telescope. This telescope is currently being used for a more conventional star survey, and the optical SETI survey is "piggybacking" on that effort. Between October 1998 and November 1999, the survey inspected about 2,500 stars. Nothing that resembled an intentional laser signal was detected, but efforts continue. The Harvard-Smithsonian group is now working with Princeton University to mount a similar detector system on Princeton's 91-centimeter (36-inch) telescope. The Harvard and Princeton telescopes will be "ganged" to track the same targets at the same time, with the intent being to detect the same signal in both locations as a means of reducing errors from detector noise. +The Harvard-Smithsonian SETI group led by Professor Paul Horowitz built a dedicated all-sky optical survey system along the lines of that described above, featuring a 1.8-meter (72-inch) telescope. The new optical SETI survey telescope is being set up at the Oak Ridge Observatory in Harvard, Massachusetts. +The University of California, Berkeley, home of SERENDIP and SETI@home, is also conducting optical SETI searches and collaborates with the NIROSETI program. The optical SETI program at Breakthrough Listen was initially directed by Geoffrey Marcy, an extrasolar planet hunter, and it involves examination of records of spectra taken during extrasolar planet hunts for a continuous, rather than pulsed, laser signal. This survey uses the Automated Planet Finder 2.4-m telescope at the Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California. The other Berkeley optical SETI effort is being pursued by the Harvard-Smithsonian group and is being directed by Dan Werthimer of Berkeley, who built the laser detector for the Harvard-Smithsonian group. This survey uses a 76-centimeter (30-inch) automated telescope at Leuschner Observatory and an older laser detector built by Werthimer. +The SETI Institute also runs a program called 'Laser SETI' with an instrument composed of several cameras that continuously survey the entire night sky searching for millisecond singleton laser pulses of extraterrestrial origin. +In January 2020, two Pulsed All-sky Near-infrared Optical SETI (PANOSETI) project telescopes were installed in the Lick Observatory Astrograph Dome. The project aims to commence a wide-field optical SETI search and continue prototyping designs for a full observatory. The installation can offer an "all-observable-sky" optical and wide-field near-infrared pulsed technosignature and astrophysical transient search for the northern hemisphere. +In May 2017, astronomers reported studies related to laser light emissions from stars, as a way of detecting technology-related signals from an alien civilization. The reported studies included Tabby's Star (designated KIC 8462852 in the Kepler Input Catalog), an oddly dimming star in which its unusual starlight fluctuations may be the result of interference by an artificial megastructure, such as a Dyson swarm, made by such a civilization. No evidence was found for technology-related signals from KIC 8462852 in the studies. + +== Quantum communications == +In a 2020 paper, Berera examined sources of decoherence in the interstellar medium and made the observation that quantum coherence +of photons in certain frequency bands could be sustained to interstellar distances. +It was suggested this would allow for quantum communication at these distances. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-7.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-7.md new file mode 100644 index 000000000..6a60a690f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-7.md @@ -0,0 +1,23 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 8/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +In a 2021 preprint, astronomer Michael Hipke described for the first time how one could search for quantum communication transmissions sent by ETI using existing telescope and receiver technology. He also provides arguments for why future searches of ETI should also target interstellar quantum communication networks. +A 2022 paper by Arjun Berera and Jaime Calderón-Figueroa noted that interstellar quantum communication by other civilizations could be possible and may be advantageous, identifying some potential challenges and factors for detecting technosignatures. They may, for example, use X-ray photons for remotely established quantum communication and quantum teleportation as the communication mode. + +== Search for extraterrestrial artifacts == +The possibility of using interstellar messenger probes in the search for extraterrestrial intelligence was first suggested by Ronald N. Bracewell in 1960 (see Bracewell probe), and the technical feasibility of this approach was demonstrated by the British Interplanetary Society's starship study Project Daedalus in 1978. Starting in 1979, Robert Freitas advanced arguments for the proposition that physical space-probes are a superior mode of interstellar communication to radio signals (see Voyager Golden Record). +In recognition that any sufficiently advanced interstellar probe in the vicinity of Earth could easily monitor the terrestrial Internet, 'Invitation to ETI' was established by Allen Tough in 1996, as a Web-based SETI experiment inviting such spacefaring probes to establish contact with humanity. The project's 100 signatories includes prominent physical, biological, and social scientists, as well as artists, educators, entertainers, philosophers and futurists. H. Paul Shuch, executive director emeritus of The SETI League, serves as the project's Principal Investigator. +Inscribing a message in matter and transporting it to an interstellar destination can be enormously more energy efficient than communication using electromagnetic waves if delays larger than light transit time can be tolerated. That said, for simple messages such as "hello," radio SETI could be far more efficient. If energy requirement is used as a proxy for technical difficulty, then a solarcentric Search for Extraterrestrial Artifacts (SETA) may be a useful supplement to traditional radio or optical searches. +Much like the "preferred frequency" concept in SETI radio beacon theory, the Earth-Moon or Sun-Earth libration orbits might therefore constitute the most universally convenient parking places for automated extraterrestrial spacecraft exploring arbitrary stellar systems. A viable long-term SETI program may be founded upon a search for these objects. +In 1979, Freitas and Valdes conducted a photographic search of the vicinity of the Earth-Moon triangular libration points L4 and L5, and of the solar-synchronized positions in the associated halo orbits, seeking possible orbiting extraterrestrial interstellar probes, but found nothing to a detection limit of about 14th magnitude. The authors conducted a second, more comprehensive photographic search for probes in 1982 that examined the five Earth-Moon Lagrangian positions and included the solar-synchronized positions in the stable L4/L5 libration orbits, the potentially stable nonplanar orbits near L1/L2, Earth-Moon L3, and also L2 in the Sun-Earth system. Again no extraterrestrial probes were found to limiting magnitudes of 17–19th magnitude near L3/L4/L5, 10–18th magnitude for L1/L2, and 14–16th magnitude for Sun-Earth L2. +In June 1983, Valdes and Freitas used the 26 m radiotelescope at Hat Creek Radio Observatory to search for the tritium hyperfine line at 1516 MHz from 108 assorted astronomical objects, with emphasis on 53 nearby stars including all visible stars within a 20 light-year radius. The tritium frequency was deemed highly attractive for SETI work because (1) the isotope is cosmically rare, (2) the tritium hyperfine line is centered in the SETI water hole region of the terrestrial microwave window, and (3) in addition to beacon signals, tritium hyperfine emission may occur as a byproduct of extensive nuclear fusion energy production by extraterrestrial civilizations. The wideband- and narrowband-channel observations achieved sensitivities of 5–14×10−21 W/m2/channel and 0.7–2×10−24 W/m2/channel, respectively, but no detections were made. +Others have speculated that we might find traces of past civilizations in our very own Solar System, on planets like Venus or Mars, although the traces would be found most likely underground. + +== Technosignatures == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-8.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-8.md new file mode 100644 index 000000000..6464d4080 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-8.md @@ -0,0 +1,25 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 9/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +Technosignatures, including all signs of technology, are a recent avenue in the search for extraterrestrial intelligence. Technosignatures may originate from various sources, from megastructures such as Dyson spheres and space mirrors or space shaders to the atmospheric contamination created by an industrial civilization, or city lights on extrasolar planets, and may be detectable in the future with large hypertelescopes. +Technosignatures can be divided into three broad categories: astroengineering projects, signals of planetary origin, and spacecraft within and outside the Solar System. +An astroengineering installation such as a Dyson sphere, designed to convert all of the incident radiation of its host star into energy, could be detected through the observation of an infrared excess from a solar analog star, or by the star's apparent disappearance in the visible spectrum over several years. After examining some 100,000 nearby large galaxies, a team of researchers has concluded that none of them display any obvious signs of highly advanced technological civilizations. +Another hypothetical form of astroengineering, the Shkadov thruster, moves its host star by reflecting some of the star's light back on itself, and would be detected by observing if its transits across the star abruptly end with the thruster in front. Asteroid mining within the Solar System is also a detectable technosignature of the first kind. +Individual extrasolar planets can be analyzed for signs of technology. Avi Loeb of the Center for Astrophysics | Harvard & Smithsonian has proposed that persistent light signals on the night side of an exoplanet can be an indication of the presence of cities and an advanced civilization. In addition, the excess infrared radiation and chemicals produced by various industrial processes or terraforming efforts may point to intelligence. +Light and heat detected from planets need to be distinguished from natural sources to conclusively prove the existence of civilization on a planet. However, as argued by the Colossus team, a civilization heat signature should be within a "comfortable" temperature range, like terrestrial urban heat islands, i.e., only a few degrees warmer than the planet itself. In contrast, such natural sources as wild fires, volcanoes, etc. are significantly hotter, so they will be well distinguished by their maximum flux at a different wavelength. +Other than astroengineering, technosignatures such as artificial satellites around exoplanets, particularly such in geostationary orbit, might be detectable even with today's technology and data, and would allow, similar to fossils on Earth, to find traces of extrasolar life from long ago. +Extraterrestrial craft are another target in the search for technosignatures . Magnetic sail interstellar spacecraft should be detectable over thousands of light-years of distance through the synchrotron radiation they would produce through interaction with the interstellar medium; other interstellar spacecraft designs may be detectable at more modest distances. In addition, robotic probes within the Solar System are also being sought with optical and radio searches. +For a sufficiently advanced civilization, hyper energetic neutrinos from Planck scale accelerators should be detectable at a distance of many Mpc. + +== Fermi paradox == + +Italian physicist Enrico Fermi suggested in the 1950s that if technologically advanced civilizations are common in the universe, then they should be detectable in one way or another. According to those who were there, Fermi either asked "Where are they?" or "Where is everybody?" +The Fermi paradox is commonly understood as asking why extraterrestrials have not visited Earth, but the same reasoning applies to the question of why signals from extraterrestrials have not been heard. The SETI version of the question is sometimes referred to as "the Great Silence". +The Fermi paradox can be stated more completely as follows: \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-9.md b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-9.md new file mode 100644 index 000000000..e06b23699 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence-9.md @@ -0,0 +1,29 @@ +--- +title: "Search for extraterrestrial intelligence" +chunk: 10/13 +source: "https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:27.948534+00:00" +instance: "kb-cron" +--- + +The size and age of the universe incline us to believe that many technologically advanced civilizations must exist. However, this belief seems logically inconsistent with our lack of observational evidence to support it. Either (1) the initial assumption is incorrect and technologically advanced intelligent life is much rarer than we believe, or (2) our current observations are incomplete, and we simply have not detected them yet, or (3) our search methodologies are flawed and we are not searching for the correct indicators, or (4) it is the nature of intelligent life to destroy itself. +There are multiple explanations proposed for the Fermi paradox, ranging from analyses suggesting that intelligent life is rare (the "Rare Earth hypothesis"), to analyses suggesting that although extraterrestrial civilizations may be common, they would not communicate with us, would communicate in a way we have not discovered yet, could not travel across interstellar distances, or destroy themselves before they master the technology of either interstellar travel or communication. +The German astrophysicist and radio astronomer Sebastian von Hoerner suggested that the average duration of civilization was 6,500 years. After this time, according to him, it disappears for external reasons (the destruction of life on the planet, the destruction of only rational beings) or internal causes (mental or physical degeneration). According to his calculations, on a habitable planet (one in three million stars) there is a sequence of technological species over a time distance of hundreds of millions of years, and each of them "produces" an average of four technological species. With these assumptions, the average distance between civilizations in the Milky Way is 1,000 light years. +Science writer Timothy Ferris has posited that since galactic societies are most likely only transitory, an obvious solution is an interstellar communications network, or a type of library consisting mostly of automated systems. They would store the cumulative knowledge of vanished civilizations and communicate that knowledge through the galaxy. Ferris calls this the "Interstellar Internet", with the various automated systems acting as network "servers". If such an Interstellar Internet exists, the hypothesis states, communications between servers are mostly through narrow-band, highly directional radio or laser links. Intercepting such signals is, as discussed earlier, very difficult. However, the network could maintain some broadcast nodes in hopes of making contact with new civilizations. +Although somewhat dated in terms of "information culture" arguments, not to mention the obvious technological problems of a system that could work effectively for billions of years and requires multiple lifeforms agreeing on certain basics of communications technologies, this hypothesis is actually testable (see below). + +=== Difficulty of detection === +A significant problem is the vastness of space. Despite piggybacking on the world's most sensitive radio telescope, astronomer and initiator of SERENDIP Charles Stuart Bowyer noted the then world's largest instrument could not detect random radio noise emanating from a civilization like ours, which has been leaking radio and TV signals for less than 100 years. For SERENDIP and most other SETI projects to detect a signal from an extraterrestrial civilization, the civilization would have to be beaming a powerful signal directly at us. It also means that Earth civilization will only be detectable within a distance of 100 light-years. + +== Post-detection disclosure protocol == +The International Academy of Astronautics (IAA) has a long-standing SETI Permanent Study Group (SPSG, formerly called the IAA SETI Committee), which addresses matters of SETI science, technology, and international policy. The SPSG meets in conjunction with the International Astronautical Congress (IAC), held annually at different locations around the world, and sponsors two SETI Symposia at each IAC. In 2005, the IAA established the SETI: Post-Detection Science and Technology Taskgroup (chairman, Professor Paul Davies) "to act as a Standing Committee to be available to be called on at any time to advise and consult on questions stemming from the discovery of a putative signal of extraterrestrial intelligent (ETI) origin." +However, the protocols mentioned apply only to radio SETI rather than for METI (Active SETI). The intention for METI is covered under the SETI charter "Declaration of Principles Concerning Sending Communications with Extraterrestrial Intelligence". +In October 2000 astronomers Iván Almár and Jill Tarter presented a paper to The SETI Permanent Study Group in Rio de Janeiro, Brazil which proposed a scale (modelled after the Torino scale) which is an ordinal scale between zero and ten that quantifies the impact of any public announcement regarding evidence of extraterrestrial intelligence; the Rio scale has since inspired the 2005 San Marino Scale (in regard to the risks of transmissions from Earth) and the 2010 London Scale (in regard to the detection of extraterrestrial life). The Rio scale itself was revised in 2018. +The SETI Institute does not officially recognize the Wow! signal as of extraterrestrial origin as it was unable to be verified, although in a 2020 Twitter post the organization stated that ''an astronomer might have pinpointed the host star''. The SETI Institute has also publicly denied that the candidate signal Radio source SHGb02+14a is of extraterrestrial origin. Although other volunteering projects such as Zooniverse credit users for discoveries, there is currently no crediting or early notification by SETI@Home following the discovery of a signal. +Some people, including Steven M. Greer, have expressed cynicism that the general public might not be informed in the event of a genuine discovery of extraterrestrial intelligence due to significant vested interests. Some, such as Bruce Jakosky have also argued that the official disclosure of extraterrestrial life may have far reaching and as yet undetermined implications for society, particularly for the world's religions. + +== Active SETI == + +Active SETI, also known as messaging to extraterrestrial intelligence (METI), consists of sending signals into space in the hope that they will be detected by an alien intelligence. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SpaceShipOne-0.md b/data/en.wikipedia.org/wiki/SpaceShipOne-0.md new file mode 100644 index 000000000..89b45f04f --- /dev/null +++ b/data/en.wikipedia.org/wiki/SpaceShipOne-0.md @@ -0,0 +1,26 @@ +--- +title: "SpaceShipOne" +chunk: 1/6 +source: "https://en.wikipedia.org/wiki/SpaceShipOne" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:26.303143+00:00" +instance: "kb-cron" +--- + +SpaceShipOne is an experimental air-launched rocket-powered aircraft with sub-orbital spaceflight capability at speeds of up to 3,000 ft/s (2,000 mph) / 910 m/s (3,300 km/h) +using a hybrid rocket motor. The design features a unique "feathering" atmospheric reentry system where the rear half of the wing and the twin tail booms folds 70 degrees upward along a hinge running the length of the wing; this increases drag while retaining stability. SpaceShipOne completed the first crewed private spaceflight in 2004. That same year, it won the US$10 million Ansari X Prize and was immediately retired from active service. Its mother ship was named "White Knight". Both craft were developed and flown by Mojave Aerospace Ventures, which was a joint venture between Paul Allen and Scaled Composites, Burt Rutan's aviation company. Allen provided the funding of approximately US$25 million. +Rutan has indicated that ideas about the project began as early as 1994 and the full-time development cycle time to the 2004 accomplishments was about three years. The vehicle first achieved supersonic flight on December 17, 2003, which was also the one-hundredth anniversary of the Wright Brothers' historic first powered flight. SpaceShipOne's first official spaceflight, known as flight 15P, was piloted by Mike Melvill. A few days before that flight, the Mojave Air and Space Port was the first commercial spaceport licensed in the United States. A few hours after that flight, Melvill became the first licensed U.S. commercial astronaut. The overall project name was "Tier One" which has evolved into Tier 1b with a goal of taking a successor ship's first passengers into space. +The achievements of SpaceShipOne are more comparable to those of the X-15 than to those of orbiting spacecraft like the Space Shuttle. Accelerating a spacecraft to orbital speed requires more than 60 times as much energy as accelerating it to Mach 3. It would also require an elaborate heat shield to safely dissipate that energy during re-entry. +SpaceShipOne's official model designation is Scaled Composites Model 316. + +== Design == + +=== Design goal === +The Scaled Composites Model 316, known as SpaceShipOne, was a spaceplane designed to: + +Carry three humans (one of them a pilot) in a sea-level pressurized cabin. +Be propelled by rocket from an altitude of 15 km (9.3 mi) to in excess of 100 km (62 mi). +Reenter atmosphere and shed kinetic energy in an aerodynamically stable configuration. +Glide transonically and subsonically. +Land horizontally on a standard runway. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SpaceShipOne-1.md b/data/en.wikipedia.org/wiki/SpaceShipOne-1.md new file mode 100644 index 000000000..90168f029 --- /dev/null +++ b/data/en.wikipedia.org/wiki/SpaceShipOne-1.md @@ -0,0 +1,29 @@ +--- +title: "SpaceShipOne" +chunk: 2/6 +source: "https://en.wikipedia.org/wiki/SpaceShipOne" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:26.303143+00:00" +instance: "kb-cron" +--- + +=== Vehicle description === +The fuselage is cigar-shaped, with an overall diameter of about 1.52 m (5 ft 0 in). The main structure is of a graphite/epoxy composite material. From front to back, it contains the crew cabin, oxidizer tank, fuel casing, and rocket nozzle. The craft has short, wide wings, with a span of 5 m (16 ft) and a chord of 3 m (9.8 ft). Large vertical tailbooms are mounted on the end of each wing, with horizontal stabilizers protruding from the tailbooms. It has gear for horizontal landings. +The overall mass of the fully fueled craft is 3,600 kg (7,900 lb), of which 2,700 kg (6,000 lb) is taken by the fully loaded rocket motor. Empty mass of the spacecraft is 1,200 kg (2,600 lb), including the 300 kg (660 lb) empty motor casing. +Originally the nozzle protruded from the back, but this turned out to be aerodynamically disadvantageous. In June 2004, between flights 14P and 15P, a fairing was added, smoothly extending the fuselage shape to meet the flared end of the nozzle. On flight 15P the new fairing overheated, due to being black on the inside and facing a hot, black nozzle. The fairing softened, and the lower part crumpled inwards during boost. Following that flight the interior of the fairing was painted white, and some small stiffening ribs were added. +The craft has a single unsteerable and unthrottleable hybrid rocket motor, a cold gas reaction control system, and aerodynamic control surfaces. All can be controlled manually. See the separate section below concerning the rocket engine. +The reaction control system is the only way to control spacecraft attitude outside the atmosphere. It consists of three sets of thrusters: thrusters at each wingtip control roll, at the top and bottom of the nose control pitch, and at the sides of the fuselage control yaw. All thrusters have redundant backups, so comprising twelve thrusters in all. +The aerodynamic control surfaces of SpaceShipOne are designed to operate in two distinct flight regimes, subsonic and supersonic. The supersonic flight regime is of primary interest during the boost phase of a flight, and the subsonic mode when gliding. The craft has separate upper and lower rudders, and elevons. These are controlled using aviation-style stick and pedals. In supersonic mode the trim tabs are controlled electrically, whereas the subsonic mode uses mechanical cable-and-rod linkage. +The wings of SpaceShipOne can be pneumatically tilted forwards into an aerodynamically stable high-drag "feathered" shape. This removes most of the need to control attitude actively during the early part of reentry: Scaled Composites refer to this as "care-free reentry". One of the early test flights actually performed re-entry inverted, demonstrating the flexibility and inherent stability of Burt Rutan's "shuttlecock" design. This feathered reentry mode is claimed to be inherently safer than the behavior at similar speeds of the Space Shuttle. The Shuttle undergoes enormous aerodynamic stresses and must be precisely steered in order to remain in a stable glide. (Although this is an interesting comparison of behavior, it is not an entirely fair comparison of design concepts: the Shuttle starts reentry at much higher speed than SpaceShipOne, and so has some very different requirements. SpaceShipOne is more similar to the X-15 vehicle.) +An early design called for a permanently shuttlecock-like shape, with a ring of feather-like stabilising fins. This would have made the spacecraft incapable of landing independently, requiring mid-air retrieval. This was deemed too risky, and the hybrid final design manages to incorporate the feathering capability into a craft that can land in a conventional manner. The tiltable rear sections of the wings and the tailbooms are collectively referred to as "the feather". +The landing gear consists of two widely separated main wheels and a nose skid. These are deployed using springs, assisted by gravity. Once deployed, they cannot be retracted inflight. +The spacecraft is incapable of independent takeoff from the ground. It requires a launch aircraft to carry it to launch altitude for an air launch. +The parts of the craft that experience the greatest heating, such as the leading edges of the wings, have about 6.5 kg (14 lb) of ablative thermal protection material applied. The main ingredient of this material was accidentally leaked to Air and Space. If it flew with no thermal protection, the spacecraft would survive reentry but would be damaged. +The spacecraft's aerodynamic design has an acknowledged "known deficiency" that makes it susceptible to roll excursions. This has been seen on SpaceShipOne flight 15P where wind shear caused a large roll immediately after ignition, and SpaceShipOne flight 16P where circumstances not yet fully understood caused multiple rapid rolls. This flaw is not considered dangerous, but in both of these flights led to the achievement of a much lower altitude than expected. The details of the flaw are not public. + +=== Cabin === +The spacecraft cabin, designed to hold three humans, is shaped as a short cylinder, diameter 1.52 m (5 ft 0 in), with a pointed forward end. The pilot sits towards the front, and two passengers can be seated behind. +The cabin is pressurized, maintaining a sea level breathable atmosphere. Oxygen is introduced to the cabin from a bottle, and carbon dioxide and water vapor are removed by absorbers. The occupants do not wear spacesuits or breathing masks, because the cabin has been designed to maintain pressure in the face of faults: all windows and seals are doubled. +The cabin has sixteen round double-pane windows, positioned to provide a view of the horizon at all stages of flight. The windows are small compared to the gaps between them, but there are sufficiently many for human occupants to patch together a moderately good view. +The nose section can be removed, and there is also a hatch below the rear windows on the left side. Crew ingress and egress is possible by either route. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SpaceShipOne-2.md b/data/en.wikipedia.org/wiki/SpaceShipOne-2.md new file mode 100644 index 000000000..92581dbbb --- /dev/null +++ b/data/en.wikipedia.org/wiki/SpaceShipOne-2.md @@ -0,0 +1,30 @@ +--- +title: "SpaceShipOne" +chunk: 3/6 +source: "https://en.wikipedia.org/wiki/SpaceShipOne" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:26.303143+00:00" +instance: "kb-cron" +--- + +=== Spaceplane navigation === +The core of the spacecraft avionics is the System Navigation Unit (SNU). Together with the Flight Director Display (FDD), it comprises the Flight Navigation Unit. The unit was developed jointly by Fundamental Technology Systems and Scaled Composites. +The SNU is a GPS-based inertial navigation system, which processes spacecraft sensor data and subsystem health data. It downlinks telemetry data by radio to mission control. +The FDD displays data from the SNU on a color LCD. It has several distinct display modes for different phases of flight, including the boost phase, coast, reentry, and gliding. The FDD is particularly important to the pilot during the boost and coast phase in order to "turn the corner" and null rates caused by asymmetric thrust. A mix of commercial and bespoke software is used in the FDD. + +=== Hybrid rocket engine === +Tier One uses a hybrid rocket engine supplied by SpaceDev, with solid hydroxyl-terminated polybutadiene (HTPB, or rubber) fuel and liquid nitrous oxide oxidizer. It generates 88 kN (20,000 lbf) of thrust, and can burn for about 87 s (1.45 min). +The physical layout of the engine is novel. The oxidizer tank is a primary structural component, and is the only part of the engine that is structurally connected to the spacecraft: the tank is in fact an integral part of the spacecraft fuselage. The tank is a short cylinder of diameter approximately 1.52 m (5 ft 0 in), with domed ends, and is the forwardmost part of the engine. The fuel casing is a narrow cylinder cantilevered to the tank, pointing backwards. The cantilevered design means that a variety of motor sizes can be accommodated without changing the interface or other components. The nozzle is a simple extension of the fuel casing; the casing and nozzle are actually a single component, referred to as the CTN (case, throat, and nozzle). Burt Rutan has applied for a patent on this engine configuration. +There is considerable use of composite materials in the engine design. The oxidizer tank consists of a composite liner with graphite/epoxy over-wrap and titanium interface flanges. The CTN uses a high-temperature composite insulator with a graphite/epoxy structure. Incorporating the solid fuel (and hence the main part of the engine) and the ablative nozzle into this single bonded component minimizes the possible leak paths. +The oxidizer tank and CTN are bolted together at the main valve bulkhead, which is integrated into the tank. There are O-rings at the interface to prevent leakage; this is the main potential leak path in the engine. The ignition system, main control valve, and injector are mounted on the valve bulkhead, inside the tank. Slosh baffles are also mounted on this bulkhead. Because the oxidizer is stored under pressure, no pump is required. +The tank liner and the fuel casing are built in-house by Scaled Composites. The tank over-wrap is supplied by Thiokol. The ablative nozzle is supplied by AAE Aerospace. The oxidizer fill, vent, and dump system is supplied by Environmental Aeroscience Corporation. The remaining components—the ignition system, main control valve, injector, tank bulkheads, electronic controls, and solid fuel casting—are supplied by SpaceDev. +The CTN must be replaced between firings. This is the only part of the craft, other than the fuel and oxidizer themselves, that must be replaced. +The solid fuel is cast with four holes. This has the disadvantage that it is possible for chunks of fuel between the holes to become detached during a burn and obstruct the flow of oxidizer and exhaust. Such situations tend to rapidly self-correct. +The oxidizer tank is filled and vented through its forward bulkhead, on the opposite side of the tank from the fuel and the rest of the engine. This improves safety. It is filled to a pressure of 4.8 MPa (700 psi) at room temperature. +The nozzle has an expansion ratio of 25:1, which is optimized for the upper part of the atmosphere. A different nozzle, with an expansion ratio of 10:1, is used for test firing on the ground. The nozzles are black on the outside, but for aerodynamic testing, red dummy nozzles are used instead. +The rocket is not throttleable. Once lit, the burn can be aborted, but the power output cannot otherwise be controlled. The thrust in fact varies, for two reasons. Firstly, as the pressure in the oxidizer tank decreases, the flow rate reduces, reducing thrust. Secondly, in the late stages of a burn the oxidizer tank contains a mixture of liquid and gaseous oxidizer, and the power output of the engine varies greatly depending on whether it is using liquid or gaseous oxidizer at a particular moment. (The liquid, being far denser, allows a greater burn rate.) +Both the fuel and oxidizer can be stored without special precautions, and they do not burn when brought together without a significant source of heat. This makes the rocket far safer than conventional liquid or solid rockets. The combustion products are water vapour, carbon dioxide, hydrogen, nitrogen, nitrogen oxides and carbon monoxide. +The engine was upgraded in September 2004, between flights 15P and 16P. The upgrade increased the oxidizer tank size, to provide greater thrust in the early part of the burn, allow a longer burn, and delay the onset of the variable thrust phase at the end of the burn. Prior to the upgrade the engine generated 76 kN (17,000 lbf) of thrust and could burn for 76 s (1.27 min). After the upgrade it was capable of 88 kN (20,000 lbf) thrust and an 87 s (1.45 min) burn. + +=== Launch aircraft === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SpaceShipOne-3.md b/data/en.wikipedia.org/wiki/SpaceShipOne-3.md new file mode 100644 index 000000000..d0cc427e6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/SpaceShipOne-3.md @@ -0,0 +1,47 @@ +--- +title: "SpaceShipOne" +chunk: 4/6 +source: "https://en.wikipedia.org/wiki/SpaceShipOne" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:26.303143+00:00" +instance: "kb-cron" +--- + +Tier One's launch aircraft, Scaled Composites Model 318, known as White Knight, is designed to take off and land horizontally and attain an altitude of about 15 km (9.3 mi), all while carrying the Tier One spacecraft in a parasite aircraft configuration. Its propulsion is by twin turbojets: afterburning J-85-GE-5 engines, rated at 15.6 kN (3,500 lbf) of thrust each. +It has the same cabin, avionics, and trim system as SpaceShipOne. This means it can flight-qualify almost all components of SpaceShipOne. It also has a high thrust-to-weight ratio and large speed brakes. These features combined allow it to be used as a high-fidelity moving platform flight simulator for SpaceShipOne. White Knight is also equipped with a trim system which (when activated) causes it to have the same glide profile as SpaceShipOne; this allows the pilots to practice for landing SpaceShipOne. The same pilots fly White Knight as fly SpaceShipOne. +The aircraft's distinctive shape features long, thin wings, in a flattened "W" shape, with a wingspan of 25 m (82 ft), dual tailplanes, and four wheels (front and rear at each side). The rear wheels retract, but the front ones, which are steerable, are permanently deployed, with small fairings, referred to as "spats", in front. Another way to look at the overall shape is as two conventional planes, with very thin fuselages, side by side and joined at their wingtips, with the cockpit and engines mounted at the point of joining. +Although White Knight was developed for certain roles in the Tier One program, it is a very capable aircraft in its own right. Scaled Composites describe it as a "high-altitude research aircraft". + +=== Flight profile === +SpaceShipOne takes off from the ground, attached to White Knight in a parasite configuration, and under White Knight's power. The combination of SpaceShipOne and White Knight can take off, land, and fly under jet power to high altitude. A captive carry flight is one where the two craft land together without launching SpaceShipOne; this is one of the main abort modes available. +For launch, the combined craft flies to an altitude of around 14 km (8.7 mi), which takes about an hour. SpaceShipOne is then drop-released, and briefly glides unpowered. Rocket ignition may take place immediately, or may be delayed. If the rocket is never lit then SpaceShipOne can glide down to the ground. This is another major abort mode, in addition to being flown deliberately in glide tests. +The rocket engine is ignited while the spacecraft is gliding. Once under power, it is raised into a 65° climb, which is further steepened in the higher part of the trajectory. The maximum acceleration during ascent was recorded at 1.70G. +By the end of the burn the craft is flying upwards at some multiple of the speed of sound, up to about 900 m/s (3,000 ft/s) and Mach 3.5, and it continues to coast upwards unpowered (i.e. ballistically). If the burn was long enough then it will exceed an altitude of 100 km (62 mi), at which height the atmosphere presents no appreciable resistance, and the craft experiences free fall for a few minutes. +While at apogee the wings are reconfigured into high-drag mode. As the craft falls back it achieves high speeds comparable to those achieved on the way up; when it subsequently reenters the atmosphere it decelerates violently, up to 5.75G. At some altitude between 10 km (6.2 mi) and 20 km (12 mi) it reconfigures into low-drag glider mode, and glides down to a landing in about 20 minutes. +White Knight takes longer to descend, and typically lands a few minutes after SpaceShipOne. + +== Specifications == + +Data from astronautix.comGeneral characteristics +Crew: One +Length: 27 ft 11 in (8.5 m) +Wingspan: 26 ft 11 in (8.2 m) +Diameter: 5 ft 0 in (1.52 m) +Wing area: 160 sq ft (15 m2) +Empty weight: 2,646 lb (1,200 kg) +Gross weight: 7,937 lb (3,600 kg) +Aspect Ratio: 1.6 +Powerplant: 1 × SpaceDev N2O/HTPB hybrid rocket, 16,500 lbf (73.5 kN) thrust +Isp: 250 s (2.5 km/s) +Burn time: 80 seconds +Performance + +Maximum speed: Mach 3.09 (2370 mph, 3815 km/h) +Range: 40 mi (65 km, 35 nmi) +Service ceiling: 367,000 ft (112,000 m) +Rate of climb: 82,000 ft/min (420 m/s) +Wing loading: 49 lb/sq ft (240 kg/m2) +Thrust/weight: 2.08 + +== Development and winning the X Prize == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SpaceShipOne-4.md b/data/en.wikipedia.org/wiki/SpaceShipOne-4.md new file mode 100644 index 000000000..70a2b9f7b --- /dev/null +++ b/data/en.wikipedia.org/wiki/SpaceShipOne-4.md @@ -0,0 +1,40 @@ +--- +title: "SpaceShipOne" +chunk: 5/6 +source: "https://en.wikipedia.org/wiki/SpaceShipOne" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:26.303143+00:00" +instance: "kb-cron" +--- + +SpaceShipOne was developed by Mojave Aerospace Ventures (a joint venture between Paul Allen and Scaled Composites, Burt Rutan's aviation company, in their Tier One program), without government funding. On June 21, 2004, it made the first privately funded human spaceflight. On October 4, it won the US$10 million Ansari X Prize, by reaching 100 kilometers in altitude twice in a two-week period with the equivalent of three people on board and with no more than ten percent of the non-fuel weight of the spacecraft replaced between flights. Development costs were estimated to be US$25 million, funded completely by Paul Allen. +During its test program, SpaceShipOne set a number of important "firsts", including first privately funded aircraft to exceed Mach 2 and Mach 3, first privately funded crewed spacecraft to exceed 100km altitude, and first privately funded reusable crewed spacecraft. +SpaceShipOne was registered with the FAA as N328KF. N is the prefix for US-registered aircraft; 328KF was chosen by Scaled Composites to stand for 328 kilofeet (about 100 kilometers), the officially designated edge of space. The original choice of registry number, N100KM, was already taken. N328KF is registered as a glider, reflecting the fact that most of its independent flight is unpowered. +SpaceShipOne's first flight, 01C, was an uncrewed captive flight test on May 20, 2003. Glide tests followed, starting with flight 03G on August 7, 2003. Its first powered flight, flight 11P, was made on December 17, 2003, the 100th anniversary of the first powered flight. +On April 1, 2004, Scaled Composites received the first license for suborbital rocket flights to be issued by the US Office of Commercial Space Transportation. This license permitted the company to conduct powered test flights over the course of one year. On June 17, 2004, under the leadership of airport CEO Stuart O. Witt, Mojave Airport reclassified itself as the Mojave Air and Space Port. +Flight 15P on June 21, 2004, was SpaceShipOne's first spaceflight, and the first privately funded human spaceflight. There were a few control problems, but these were resolved prior to the Ansari X PRIZE flights that followed, with flight 17P to 112 km on October 4, 2004, winning the prize. +The SpaceShipOne Team was awarded the Space Achievement Award by the Space Foundation in 2005. + +=== Flights === +On 17 December 2003—on the 100th anniversary of the Wright brothers first powered flight of an aircraft—SpaceShipOne, piloted by Brian Binnie on Flight 11P, made its first rocket-powered flight and became the first privately built craft to achieve supersonic flight. + +All of the flights of SpaceShipOne were from the Mojave Airport Civilian Flight Test Center. Flights were numbered, starting with flight 01 on May 20, 2003. One or two letters are appended to the number to indicate the type of mission. An appended C indicates that the flight was a captive carry, G indicates an unpowered glide, and P indicates a powered flight. If the actual flight differs in category from the intended flight, two letters are appended: the first indicating the intended mission and the second the mission actually performed. + +The flights were accompanied by two chase planes—an Extra 300 owned and flown by Chuck Coleman, and a Beechcraft Starship. + +=== Astronauts === +The SpaceShipOne pilots came from a variety of aerospace backgrounds. Mike Melvill was a test pilot, Brian Binnie was a former Navy pilot, and Peter Siebold is an engineer at Scaled Composites. They qualified to fly SpaceShipOne by training on the Tier One flight simulator and in White Knight and other Scaled Composites aircraft. + +== Retirement == + +SpaceShipOne's space flights were watched by large crowds at Mojave Spaceport. A fourth suborbital flight, Flight 18P, was originally scheduled for October 13, 2004. However, Burt Rutan decided not to risk damage to the historic craft, and cancelled it and all future flights. +On July 25, 2005, SpaceShipOne was taken to the Oshkosh Airshow in Oshkosh, Wisconsin. After the airshow, Mike Melvill and crew flew the White Knight, carrying SpaceShipOne, to Wright-Patterson Air Force Base in Dayton, Ohio, where Melvill spoke to a group of about 300 military and civilian personnel. Later in the evening, Melvill gave a presentation at the Dayton Engineers Club, entitled "Some Experiments in Space Flight", in honor of Wilbur Wright's now-famous presentation to the American Society of Mechanical Engineers in 1901 entitled "Some Experiments in Flight". The White Knight then transported SpaceShipOne to the Smithsonian Institution's National Air and Space Museum to be put on display. It was unveiled on Wednesday October 5, 2005 in the Milestones of Flight gallery and is now on display to the public in the main atrium with the Spirit of St. Louis, the Bell X-1, and the Apollo 11 command module Columbia. +Commander Brian Binnie donated the flight suit and checklist used during his Ansari X Prize-winning flight to an auction benefitting Seattle's Museum of Flight. Entertainer and fundraising auctioneer Fred Northup Jr. purchased the flight suit and checklist book, and the flight suit is on display at the museum's Charles Simonyi Space Gallery. +A piece of SpaceShipOne's carbon fiber material was launched aboard the New Horizons mission to Pluto in 2006. + +== Replicas == + +A year after its appearance in the Oshkosh Airventure airshow, the Experimental Aircraft Association featured a full-scale replica of the spacecraft in a wing of its museum which housed other creations of Burt Rutan. Using the same fiberglass molds as the original, it was so exact in its replication—despite not having any doors or interior—that it was dubbed "Serial 2 Scaled" by Scaled Composites. Each detail in its appearance was matched, down to the N328KF registration number on its fuselage. It is so precise that, during a 7-minute video presentation held every hour on the half hour in the museum, it can display the two different modes of its 'feathering' ability, albeit through the aid of pulleys and wires (there is no machinery in the replica). + +Locations of other full-scale replicas: \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SpaceShipOne-5.md b/data/en.wikipedia.org/wiki/SpaceShipOne-5.md new file mode 100644 index 000000000..aae7f74e7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/SpaceShipOne-5.md @@ -0,0 +1,40 @@ +--- +title: "SpaceShipOne" +chunk: 6/6 +source: "https://en.wikipedia.org/wiki/SpaceShipOne" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:26.303143+00:00" +instance: "kb-cron" +--- + +William Thomas Terminal at Meadows Field Airport in Bakersfield +Mojave Spaceport's Legacy Park alongside the original Roton Atmospheric Test Vehicle +Flying Heritage Collection at Paine Field in Everett +Hiller Aviation Museum at San Carlos Airport (California) +Google's Mountain View Campus +Frontiers of Flight Museum, Dallas Love Field, Dallas, Texas. +SpaceShipOne was also made into a model rocket in 2004. + +== Subsequent spacecraft == +With the success of Tier One meeting its project goals, a successor project started in 2004 was Tier 1b. The successor ships are named SpaceShipTwo and White Knight Two. The name of the joint venture between Virgin Group and Scaled Composites is called The Spaceship Company, with a goal of carrying passengers under the name Virgin Galactic, a spaceliner with an initial target of a commercial fleet of five spacecraft. +In August 2005, Virgin Galactic stated that if the upcoming suborbital service with SpaceShipTwo would be successful, the follow-up would be known as SpaceShipThree. +On 13 December 2018, VSS Unity achieved the SpaceShipTwo project's first suborbital space flight, VSS Unity VP-03, with two pilots, reaching an altitude of 82.7 kilometres (51.4 mi), and officially entering outer space by US standards. + +== Gallery == + +== See also == + +2004 in spaceflight +Black Sky: The Race For Space, 2005 documentary about SpaceShipOne +X-15 +SpaceShipTwo +FAST20XX ALPHA vehicle based on SpaceShipOne + +== References == + +SpaceShipOne: An Illustrated History by Dan Linehan, foreword by Arthur C. Clarke (Zenith Press, 2008). ISBN 978-0-7603-3188-0. + +== External links == + +Footage of SpaceShipOne landing and press conference with pilot Mike Melvill \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Steven_J._Dick-0.md b/data/en.wikipedia.org/wiki/Steven_J._Dick-0.md new file mode 100644 index 000000000..3fe81b2b1 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Steven_J._Dick-0.md @@ -0,0 +1,74 @@ +--- +title: "Steven J. Dick" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Steven_J._Dick" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:02.244344+00:00" +instance: "kb-cron" +--- + +Steven J. Dick (born October 24, 1949, Evansville, Indiana) is an American astronomer, author, and historian of science most noted for his work in the field of astrobiology. Dick served as the chief historian for the National Aeronautics and Space Administration (NASA) from 2003 to 2009 and as the Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology from 2013 to 2014. Before that, he was an astronomer and historian of science at the United States Naval Observatory in Washington, DC, from 1979 to 2003. + + +== Early life and education == + +Dick graduated from Mt. Vernon High School in 1967. He received a Bachelor of Science in astrophysics from Indiana University Bloomington in 1971. He earned a Master of Arts in 1974 and a Ph.D. in 1977 in the history and philosophy of science, both from Indiana University. + + +== Career == +For 24 years, Dick worked as an astronomer and historian of science for United States Naval Observatory in Washington, D.C., including three years at the Naval Observatory's Southern Hemisphere station in New Zealand. There he was part of a team using transit telescopes and astrographs to chart the northern and southern skies. During this time, he also wrote the history of the Observatory, the first national observatory of the United States, published as Sky and Ocean Joined: The U. S. Naval Observatory, 1830-2000. +In 2003, he was named the Chief Historian for the National Aeronautics and Space Administration. During his years at NASA, Dick wrote on the importance of exploration to society, commissioned numerous histories of spaceflight, and edited several volumes on the societal impact of space flight and on the occasion of the 50th anniversaries of NASA and the space age. +Dick served as Chairman of the Historical Astronomy Division of the American Astronomical Society (1993–1994), as President of the History of Astronomy Commission of the International Astronomical Union (1997-2000) and as President of the Philosophical Society of Washington. He is on the editorial board for the Journal for the History of Astronomy and the Journal of Astronomical History and Heritage. From 2011-2012 he held the Charles A. Lindbergh Chair in Aerospace History at the National Air & Space Museum. In 2013 Dick was named the Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology. + + +== Astrobiology == +Dick received the NASA Group Achievement Award "for initiating the new NASA multidisciplinary program in astrobiology, including the definition of the field of astrobiology, the formulation and initial establishment of the NASA Astrobiology Institute, and the development of a Roadmap to guide future NASA investments in astrobiology." +Dick's published work in the field of astrobiology includes Plurality of Worlds: The Origins of the Extraterrestrial Life Debate from Democritus to Kant (Cambridge University Press, 1982); The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science (Cambridge University Press, 1996); Life on Other Worlds: The 20th Century Extraterrestrial Life Debate (1998), and, with James Strick, The Living Universe: NASA and the Development of Astrobiology (2005). They argue that since the ancient Greeks, extraterrestrial life has been a theme tied to scientific cosmologies, including the ancient atomist, Copernican, Cartesian, and Newtonian worldviews. Dick argues that from an epistemological point of view the methods of astrobiology in the twentieth century are as empirical as in any historical science such as astronomy or geology. Dick has also surveyed the field of astrobiology in "Critical Issues in the History, Philosophy, and Sociology of Astrobiology" (Astrobiology, Volume 12, Number 10, 2012). On December 4, 2013, while holding the NASA/Library of Congress Chair in Astrobiology, Dick testified on astrobiology before the U.S. House of Representatives Committee on Science, Space, and Technology, arguing that SETI funding should be restored and integrated with the NASA astrobiology program. + + +=== Intelligence Principle === +The intelligence principle is a hypothetical idea of Dick's in the field of cultural evolution. Outlined in his 2003 paper "Cultural Evolution, the Postbiological Universe and SETI", the intelligence principle describes a potential binding tendency among all intelligent societies, both terrestrial and extraterrestrial: + +The maintenance, improvement and perpetuation of knowledge and intelligence is the central driving force of cultural evolution, and that to the extent intelligence can be improved, it will be improved. + + +== Honors == +Dick is the recipient of the NASA Exceptional Service Medal and the Navy Meritorious Civilian Service Medal. In 2006, Dick received the LeRoy E. Doggett Prize from the American Astronomical Society for a career that has significantly influenced the field of the history of astronomy. Also in 2006, Dick was selected to deliver the first Billingham Cutting Edge Lecture, at the International Astronautical Congress in Valencia, Spain. In 2009, minor planet 6544 Stevendick was named in his honor. In 2012, he was elected a Fellow of the American Association for the Advancement of Science. + + +== Selected publications == +Plurality of Worlds: The Origins of the Extraterrestrial Life Debate from Democritus to Kant (Cambridge University Press, 1982) ISBN 0-521-31985-4 +The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science (Cambridge University Press, 1996) ASIN B000UUKKY6 +Life on Other Worlds: The 20th Century Extraterrestrial Life Debate (Cambridge University Press, 2001) ISBN 0-521-79912-0 +Many Worlds: The New Universe, Extraterrestrial Life and the Theological Implications (Templeton Foundation Press, 2000) ISBN 1-890151-42-4 +The Living Universe: NASA and the Development of Astrobiology (Rutgers University Press, 2005) (co-authored with James Strick) ISBN 0-8135-3733-9 +Sky and Ocean Joined – The U.S. Naval Observatory 1830-2000 (Cambridge University Press, 2003) ISBN 0-521-81599-1 +Editor (with Roger Launius), Critical Issues in the History of Spaceflight (NASA SP 4702, 2006) +Editor (with Roger Launius), "Societal Impact of Spaceflight" (NASA SP 4801, 2007) +Editor (with Neil Armstrong et al.), America in Space: NASA's First Fifty Years, (Abrams, 2007). +Editor, Remembering the Space Age (NASA SP 4703, 2008) +Editor (with Mark Lupisella), Cosmos and Culture: Cultural Evolution in a Cosmic Context (NASA SP 4802, 2009) +Editor, NASA's First 50 Years: Historical Perspectives (NASA SP 4704, 2010) +Discovery and Classification in Astronomy: Controversy and Consensus (Cambridge University Press, 2013) +Editor, Historical Studies in the Societal Impact of Spaceflight (NASA, 2015) +Editor, The Impact of Discovering Life Beyond Earth (Cambridge University Press, 2015). +Astrobiology, Discovery, and Societal Impact: Controversy and Consensus (Cambridge University Press, 2018). +Classifying the Cosmos: How We Can Make Sense of the Celestial Landscape (Springer, 2019). +Space, Time, and Aliens: Collected Works on Cosmos and Culture (Springer, 2020). + + +== See also == +Megatrajectory +Sociology of knowledge +Intelligence explosion + + +== References == + + This article incorporates public domain material from websites or documents of the United States government. + + +== External links == +Oral history interview transcript with Steven J. Dick on 2 September 2020, American Institute of Physics, Niels Bohr Library & Archives +Steven J. Dick's web site \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency-0.md b/data/en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency-0.md index 0f7c24ffd..bc3e8331f 100644 --- a/data/en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency-0.md +++ b/data/en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency-0.md @@ -4,7 +4,7 @@ chunk: 1/2 source: "https://en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:31:09.670612+00:00" +date_saved: "2026-05-05T13:15:09.622823+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency-1.md b/data/en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency-1.md index b0c358a1b..1cdb1af41 100644 --- a/data/en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency-1.md +++ b/data/en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency-1.md @@ -4,7 +4,7 @@ chunk: 2/2 source: "https://en.wikipedia.org/wiki/Stimulus-triggered_acquisition_of_pluripotency" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:31:09.670612+00:00" +date_saved: "2026-05-05T13:15:09.622823+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Technosignature-0.md b/data/en.wikipedia.org/wiki/Technosignature-0.md new file mode 100644 index 000000000..ab920a2c6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Technosignature-0.md @@ -0,0 +1,35 @@ +--- +title: "Technosignature" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Technosignature" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:30.429354+00:00" +instance: "kb-cron" +--- + +Technosignature or technomarker is any measurable property or effect that provides scientific evidence of past or present technology. Technosignatures are analogous to biosignatures, which signal the presence of life, whether intelligent or not. Some authors prefer to exclude radio transmissions from the definition, but such restrictive usage is not widespread. Jill Tarter has proposed that the search for extraterrestrial intelligence (SETI) be renamed "the search for technosignatures". Various types of technosignatures, such as radiation leakage from megascale astroengineering installations such as Dyson spheres, the light from an extraterrestrial ecumenopolis, or Shkadov thrusters with the power to alter the orbits of stars around the Galactic Center, may be detectable with hypertelescopes. Some examples of technosignatures are described in Paul Davies's 2010 book The Eerie Silence, although the terms "technosignature" and "technomarker" do not appear in the book. +In February 2023, astronomers reported, after scanning 820 stars, the detection of 8 possible technosignatures for follow-up studies. + +== Astroengineering projects == + +A Dyson sphere, constructed by life forms dwelling in proximity to a Sun-like star, would cause an increase in the amount of infrared radiation in the star system's emitted spectrum. Hence, Freeman Dyson selected the title "Search for Artificial Stellar Sources of Infrared Radiation" for his 1960 paper on the subject. SETI has adopted these assumptions in its search, looking for such "infrared heavy" spectra from solar analogs. Since 2005, Fermilab has conducted an ongoing survey for such spectra, analyzing data from the Infrared Astronomical Satellite. +Identifying one of the many infra-red sources as a Dyson sphere would require improved techniques for discriminating between a Dyson sphere and natural sources. Fermilab discovered 17 "ambiguous" candidates, of which four have been named "amusing but still questionable". Other searches also resulted in several candidates, which remain unconfirmed. In October 2012, astronomer Geoff Marcy, one of the pioneers of the search for extrasolar planets, was given a research grant to search data from the Kepler telescope, with the aim of detecting possible signs of Dyson spheres. + +=== Orbital paths, transit signatures, stellar activity and star-system composition === + +Shkadov thrusters, with the hypothetical ability to change the orbital paths of stars in order to avoid various dangers to life such as cold molecular clouds or cometary impacts, would also be detectable in a similar fashion to the transiting extrasolar planets searched by Kepler. Unlike planets, though, the thrusters would appear to abruptly stop over the surface of a star rather than crossing it completely, revealing their technological origin. In addition, evidence of targeted extrasolar asteroid mining may also reveal extraterrestrial intelligence (ETI). Furthermore, it has been suggested that information could be hidden within the transit signatures of other planets. Advanced civilizations could "cloak their presence, or deliberately broadcast it, through controlled laser emission". Other characteristics proposed as potential technosignatures (or starting points for detection of clearer signatures) include peculiar orbital periods such as arranging planets in prime number patterns. Coronal and chromospheric activity on stars might be altered. Extraterrestrial civilizations may use free-floating planets (rogue planets) for interstellar transportation with a number of proposed possible technosignatures. + +=== Communication networks === + +A study suggests that if ETs exist, they may have established communications network(s) and may already have probes in the Solar System whose communication may be detectable. Studies by John Gertz suggest flyby (scout) probes might intermittently surveil nascent planetary systems and permanent probes would communicate with a home base, potentially using triggers and conditions such as detection of electromagnetic leakage or biosignatures. They also suggest several strategies to detecting local ET probes such as detecting emitted optical messages. He also finds that due to interstellar networks of communications nodes, the search for deliberate interstellar signals – as is common in SETI – may be futile. The architecture may consist of nodes separated by sub-light-year distances and strung out between neighboring stars. It may also contain pulsars as beacons or nodes whose beams are modulated by mechanisms that could be searched for. Moreover, a study suggests prior searches wouldn't have detected cost-effective electromagnetic signal beacons. + +== Planetary analysis == + +=== Artificial heat and light === + +Various astronomers, including Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. Edwin L. Turner of Princeton University, and Thomas Beatty of the University of Wisconsin have proposed that artificial light from extraterrestrial planets, such as that originating from cities, industries, and transport networks, could be detected and signal the presence of an advanced civilization. +Light and heat detected from planets must be distinguished from natural sources to conclusively prove the existence of intelligent life on a planet. For example, NASA's 2012 Black Marble experiment showed that significant stable light and heat sources on Earth, such as chronic wildfires in arid Western Australia, originate from uninhabited areas and are naturally occurring. +Spectroscopic observations of exoplanet nightsides would be able to identify artificial lighting via its distinct spectroscopic signature. Work by astronomer Thomas Beatty has shown that the spectrally concentrated emission from sodium street lights would be distinguishable from natural sources using proposed next generation space telescopes. The proposed Large Ultraviolet Optical Infrared Surveyor may be able to detect city lights twelve times those of Earth on Proxima b in 300 hours. + +=== Atmospheric analysis === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Technosignature-1.md b/data/en.wikipedia.org/wiki/Technosignature-1.md new file mode 100644 index 000000000..9b4213759 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Technosignature-1.md @@ -0,0 +1,39 @@ +--- +title: "Technosignature" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Technosignature" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:30.429354+00:00" +instance: "kb-cron" +--- + +Atmospheric analysis of planetary atmospheres, as is already done on various Solar System bodies and in a rudimentary fashion on several hot Jupiter extrasolar planets, may reveal the presence of chemicals produced by technological civilizations. For example, atmospheric emissions from human technology use on Earth, including nitrogen dioxide and chlorofluorocarbons, are detectable from space. Artificial air pollution may therefore be detectable on extrasolar planets and on Earth via "atmospheric SETI" – including NO2 pollution levels and with telescopic technology close to today. Such technosignatures may consist not of the detection of the level of one specific chemical but simultaneous detections of levels of multiple specific chemicals in atmospheres. +However, there remains a possibility of mis-detection; for example, the atmosphere of Titan has detectable signatures of complex chemicals that are similar to what on Earth are industrial pollutants, though not the byproduct of civilisation. Some SETI scientists have proposed searching for artificial atmospheres created by planetary engineering to produce habitable environments for colonisation by an ETI. + +== Extraterrestrial artifacts and spacecraft == + +=== Spacecraft === + +Interstellar spacecraft may be detectable from hundreds to thousands of light-years away through various forms of radiation, such as the photons emitted by an antimatter rocket or cyclotron radiation from the interaction of a magnetic sail with the interstellar medium. Such a signal would be easily distinguishable from a natural signal and could hence firmly establish the existence of extraterrestrial life, were it to be detected. In addition, smaller Bracewell probes within the Solar System itself may also be detectable by means of optical or radio searches. Self-replicating spacecraft or their communications networks could potentially be detectable within the Solar system or in nearby star-based systems, if they are located there. + +=== Satellites === +A less advanced technology, and one closer to humanity's current technological level, is the Clarke Exobelt proposed by Astrophysicist Hector Socas-Navarro of the Instituto de Astrofisica de Canarias. This hypothetical belt would be formed by all the artificial satellites occupying geostationary/geosynchronous orbits around an exoplanet. From early simulations it appeared that a very dense satellite belt, requiring only a moderately more-advanced civilization than ours, would be detectable with existing technology in the light curves from transiting exoplanets, but subsequent analysis has questioned this result, suggesting that exobelts detectable by current and upcoming missions will be very rare. + +=== On exoplanets === +Low- or high-albedo installations such as solar panels may also be detectable, albeit distinguishing artificial megastructures from high- and low-albedo natural environments (e.g., bright ice caps) may make it unfeasible. + +== Scientific projects searching for technosignatures == + +One of the first attempts to search for Dyson Spheres was made by Vyacheslav Slysh from the Russian Space Research Institute in Moscow in 1985 using data from the Infrared Astronomical Satellite (IRAS). +Another search for technosignatures, c. 2001, involved an analysis of data from the Compton Gamma Ray Observatory for traces of anti-matter, which, besides one "intriguing spectrum probably not related to SETI", came up empty. +In 2005, Fermilab had an ongoing survey for such spectra by analyzing data from IRAS. Identifying one of the many infra-red sources as a Dyson Sphere would require improved techniques for discriminating between a Dyson Sphere and natural sources. Fermilab discovered 17 potential "ambiguous" candidates of which four have been named "amusing but still questionable". Other searches also resulted in several candidates, which are, however, unconfirmed. +In a 2005 paper, Luc Arnold proposed a means of detecting planetary-sized artifacts from their distinctive transit light curve signature. He showed that such technosignature was within the reach of space missions aimed at detecting exoplanets by the transit method, as were Corot or Kepler projects at that time. The principle of the detection remains applicable for future exoplanets missions. +In 2012, a trio of astronomers led by Jason Wright started a two-year search for Dyson Spheres, aided by grants from the Templeton Foundation. +In 2013, Geoff Marcy received funding to use data from the Kepler Telescope to search for Dyson Spheres and interstellar communication using lasers, and Lucianne Walkowicz received funding to detect artificial signatures in stellar photometry. +Starting in 2016, astronomer Jean-Luc Margot of UCLA has been searching for technosignatures with large radio telescopes. + +=== Vanishing stars === +In 2016, it was proposed that vanishing stars are a plausible technosignature. A pilot project searching for vanishing stars was carried out, finding one candidate object. In 2019, the Vanishing & Appearing Sources during a Century of Observations (VASCO) project began more general searches for vanishing and appearing stars, and other astrophysical transients They identified 100 red transients of "most likely natural origin", while analyzing 15% of the image data. In 2020, the VASCO collaboration started up a citizen science project, vetting through images of many thousands of candidate objects. The citizen science project is carried out in close collaboration with schools and amateur associations mainly in African countries. The VASCO project has been referred to as "Perhaps the most general artefact search to date". In 2021, VASCO's principal investigator Beatriz Villarroel received a L'Oreal-Unesco prize in Sweden for the project. In June 2021, the collaboration published the discovery of nine light sources seemingly appearing and vanishing simultaneously from archival plates taken in 1950. Villarroel's team also found three 16th magnitude stars which had vanished on plates exposed within one hour of each other on 19 July 1952. + +=== Organization of novel projects === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Technosignature-2.md b/data/en.wikipedia.org/wiki/Technosignature-2.md new file mode 100644 index 000000000..69299004f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Technosignature-2.md @@ -0,0 +1,29 @@ +--- +title: "Technosignature" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Technosignature" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:15:30.429354+00:00" +instance: "kb-cron" +--- + +In June 2020, NASA was awarded their first SETI-specific grant in three decades. The grant funds the first NASA-funded search for technosignatures from advanced extraterrestrial civilizations other than radio waves, including the creation and population of an online technosignature library. A 2021 scientific review produced by the i.a. NASA-sponsored online workshop TechnoClimes 2020 classified possible optimal mission concepts for the search of technosignatures. It evaluates signatures based on a metric about the distance of humanity to the capacity of developing the signature's required technology – a comparison to contemporary human technology footprints, associated methods of detection and ancillary benefits of their search for other astronomy. The study's conclusions include a robust rationale for organizing missions for searching artifacts – including probes – within the Solar system. +In 2021, astronomers proposed a sequence of "verification checks for narrowband technosignature signals" after concluding that technosignature candidate BLC1 could be the result of a form of local radiofrequency interference. + +It has been suggested that observatories on the far side of the Moon may mitigate radio interference from Earth. In 2022, scientists provided an overview of the capabilities of ongoing, recent, past, planned and proposed missions and observatories for detecting various alien technosignatures. + +== Implications of detection == + +Steven J. Dick states that there generally are no principles for dealing with successful SETI detections. Detections of technosignatures may have ethical implications, such as conveying information related to astroethical and related machine ethics ones (e.g., related to machines' applied ethical values), or include information about alien societies or histories or fates, which may vary depending on the type, prevalence and form of the detected signature's technology. Moreover, various types of information about detected technosignatures and their distribution or dissemination may have varying implications that may also depend on time and context. +Beyond astronomy and astrobiology, detection would raise significant methodological questions about how we search for life. Research into detection windows suggests that advancing technology on both sides; human and extraterrestrial, could so rapidly evolve that the period during which their technosignatures are visible to us might be brief, potentially explaining why prior searches have come up empty and indicating the need for broader, multi-wavelength detection strategies. + +== See also == +Laser SETI +Quiet and loud aliens – Concept in astrobiology +Kardashev scale – Measure of a civilization's evolution + +== Further reading == +Participants, NASA Technosignatures Workshop (28 January 2019). NASA and the Search for Technosignatures: A Report from the NASA Technosignatures Workshop. arXiv:1812.08681v2. + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/The_Galileo_Project-0.md b/data/en.wikipedia.org/wiki/The_Galileo_Project-0.md new file mode 100644 index 000000000..591f16d20 --- /dev/null +++ b/data/en.wikipedia.org/wiki/The_Galileo_Project-0.md @@ -0,0 +1,32 @@ +--- +title: "The Galileo Project" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/The_Galileo_Project" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:19.736412+00:00" +instance: "kb-cron" +--- + +The Galileo Project is an international scientific research project to search for extraterrestrial intelligence or extraterrestrial technology on and near Earth and to identify the nature of anomalous Unidentified Flying Objects/Unidentified Aerial Phenomena (UFOs/UAP). +It was launched in 2021 by Harvard University astrophysicist, Avi Loeb, shortly after the ODNI UFO report (prepared by the U.S. Intelligence), which reported sightings of aircraft or other devices apparently flying at mysterious speeds or trajectories, and a 3 June 2021 speech by the head of NASA, Bill Nelson, in which he stated scientific analysis of Unidentified Aerial Phenomena detected by a multitude of instruments was needed. On 5 June, Loeb emailed NASA to suggest such a scientific project but received no reply upon which he launched the project on his own on 26 July 2021 with the help of donations. +The non-profit project is searching for extraterrestrial technological equipment, which can be considered to be technosignatures, including gathering new data about peculiar UFOs with dedicated optimized unclassified sensor systems. + +== Overview == +The project aims to use existing and new telescopes to systematically look for artifacts in Earth's orbit, interstellar objects, and unexplained craft, sometimes called "anomalous aerial vehicles" (AAV), in Earth's atmosphere. Research into UFOs, including ufology, has often been criticized for working with or providing only little or low-quality data, especially as adherence to the "extraordinary claims require extraordinary evidence" adage is a guiding principle of scientific inquiry. The project aims to address the data-quality issue by setting up new sensor systems. The project aims to make the collected data publicly available to scientific scrutiny and publish papers with "transparent" scientific analysis in peer-reviewed scientific journals. Loeb notes that "people in the military or in politics are not trained as scientists, and should not be asked to interpret what they see in the sky." The project uses an agnostic (or "secular" or "unbiased, empirical inquiry") approach by which no potential explanations – including those that are considered to be unlikely by some experts – are rejected a priori but data is gathered and scientifically investigated to, based on the results, develop any conclusions. +Its two other main avenues of research are searching for "two further types of potential extraterrestrial technological signatures with the use of AI": 'Oumuamua-like interstellar objects, and non-manmade artificial satellites. +Over 100 scientists worldwide are involved in the project. +In July 2023, astronomer Avi Loeb and his team reported the possibility of finding interstellar material. Claims made by Loeb and his team about their findings have been doubted by their peers according to a report in The New York Times. + +== Activities == + +Loeb has stated that at a minimum, the "Galileo Project will gather rich data sets that may foster the discovery of – or better scientific explanations for – novel interstellar objects with anomalous properties, and for potential new natural phenomena or terrestrial technology explanations for many presently inexplicable UAP". + +=== Telescopes === +One project aims to construct a series of optical and infrared telescopes to monitor the sky and use artificial intelligence to classify and analyse the observations. Its first telescope was installed on the roof of the Harvard College Observatory in 2022. More sensor systems are planned to be deployed worldwide, possibly in a networked way. In September 2022, it was reported that the project should begin collecting observations in January and Loeb has stated in an online post on 24 October that instruments designed by the Galileo Project are "by now collecting new high-quality data". +The telescope systems use machine learning to sort out, for example, "birds, balloons, drones, atmospheric events, aircraft and satellites from more mysterious sightings". +The telescopes could be supplemented by radar systems that would "distinguish a physical object in the sky from a weather pattern or a mirage". Moreover, like NASA for their UAP study, the project is looking into also using Earth observation satellites, in particular data collected by miniature satellites by Planet Labs. +Loeb has stated that so far SETI was mainly "predicated on the assumption that extraterrestrials communicate via radio waves, a technology we have used for just over a century and which advanced extraterrestrials may have long ago left behind", noting that a better strategy may be "to look for artefacts: alien tech". Astronomer Jason Wright affirms that "very little" of such searching is being done, but "artefact SETI" seems to "have got more traction lately". Artefacts may have been able to accumulate in the Solar System – like our "mailbox" – for 4.55 billion years. +A goal of the project is to capture "new crisp images with better instruments than have ever been used by civilians". While relevant sensors are not only photographic cameras, Loeb stated in early 2022 that high-resolution images could be collected within two years. + +=== Study of interstellar objects like 'Oumuamua === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/The_Galileo_Project-1.md b/data/en.wikipedia.org/wiki/The_Galileo_Project-1.md new file mode 100644 index 000000000..e63ad4563 --- /dev/null +++ b/data/en.wikipedia.org/wiki/The_Galileo_Project-1.md @@ -0,0 +1,33 @@ +--- +title: "The Galileo Project" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/The_Galileo_Project" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:19.736412+00:00" +instance: "kb-cron" +--- + +The project plans to search for, characterize and study interstellar objects (ISOs) like the peculiar 'Oumuamua detected in 2017. They intend to use astronomical surveys like the Vera C. Rubin Observatory so that such objects can be identified more quickly, and to design a space mission so a probe could intercept it and gather close-up data. The team intends to develop software that "will analyze data collected from the Vera Rubin Observatory". It is thought that when the observatory commences its Legacy Survey of Space and Time (LSST), "it will be able to detect ISOs entering our Solar System at a rate of a few per month". +In collaboration with Alan Stern, principal investigator of NASA's New Horizons mission, they have received funding to develop such a space mission concept. +The project may trace its origins back to 2017 when its founder, Loeb, first got excited about the topic and gained substantial public attention after the first known interstellar object, ’Oumuamua, was discovered and displayed highly unusual properties and behavior. Loeb investigated and elaborated these anomalies and proposed that it could be a kind of extraterrestrial technology in scientific journals, many media appearances and a book, Extraterrestrial: The First Sign of Intelligent Life Beyond Earth. +The Interstellar Object Studies branch is led by Amir Siraj, a Harvard astrophysicist who frequently collaborates with Loeb and co-discoverer of one or two (see below) interstellar objects. +In 2022, Siraj and Loeb reported the discovery of an additional candidate interstellar meteor, CNEOS 2017-03-09, in a preprint using the same fireball catalog as they used for CNEOS 2014-01-08 (see below). They find that the implied material strength of the two objects (these are the highest and third-highest of the catalog's 273 fireballs) suggests that interstellar meteors "come from a population with material strength characteristically higher than meteors originating from within the solar system". + +=== Deep-ocean expedition to recover CNEOS 2014-01-08 fragments === + +The project focused on the 2014 meteor CNEOS 2014-01-08, which Loeb and Siraj claimed was "rare both in composition and in speed", leading them to claim it was an interstellar object. +Loeb announced that private philanthropists were funding an expedition to search the floor in the suspected region of impact by dragging a magnetic sled on the seafloor off the coast of Papua New Guinea. In 2023 Loeb announced the discovery of an anomalous 8-millimeter-long curled piece of wire, designated "ISI-2". X-ray fluorescence analysis determined it was chiefly composed of Manganese and Platinum, commonly used in the manufacture of corrosion resistant laboratory electrodes. However, the relative composition of the elements in the wire was significantly different than that used in electrodes. +Additionally, metallic shards were discovered that were determined to be composed of a S5 steel alloy, which bears a yield strength that far exceeds that of iron meteorites, reflecting previously published results that characterized IM1's strength. Two varieties were found, dubbed "red" and "gray" which are representative of a differing oxidation state. Further fragments were found several kilometers away. +The scientific community remained skeptical of all the associated claims, from whether the meteor was interstellar, to whether it landed in that part of the ocean, to whether fragments could be recovered, to whether or not those specific objects found were of off earth origin. The seismic data on which Loeb partially based his estimate of the impact site was shown to be the result, not of an impact, but of nearby truck traffic. + +=== Search for non-human artificial satellites === +The project intends to systematically search for non-manmade artificial satellites (or semi-artificial satellites or artifacts on them) in Earth's orbit – for example by designing algorithms for telescopes to recognize and filter orbiting objects and using modern sky surveys. +An object in a geosynchronous orbit may have been there for many millions of years and both intact material, as well as debris from degraded probes, could be detected even if they have undergone multiple collisions during this period. As any "high-albedo objects are moving, spinning and emitting reflections from time to time", it should be possible to "confirm their existence through customized searches of modern data". The project can search for "these glinting events more effectively than was possible with other surveys". + +== Members == +The team includes scientists who as of 2021 work on a voluntary basis from Caltech, Cambridge University, Harvard, Princeton, Stockholm University, the University of Tokyo, and other institutions. The project also lists "Affiliated professionals who offer useful expertise and input to the Research Team", and members of a "Scientific Advisory Board" and a "Philanthropic Advisory Board". + +== Funding == +Its activities are funded by donations – $1.8 million as of 2021. The funders include Frank Laukien, CEO of Bruker Corporation and William A. Linton, founder of Promega Corporation, both listed on the project's Philanthropic Advisory Board. The donations are reported to be unconditional and philanthropic. Further funding that covers the costs of an expedition to retrieve fragments of an interstellar object was announced in September 2022. +Loeb has stated that around $100 million would be needed to fully realize its project of identifying the nature of UAP. Loeb has pointed out that research of dark matter is a still unsolved topic that he suggests to be "just as bizarre as aliens and far less relevant to daily human life" and that $100 million are only two percent of the Large Hadron Collider's "$5bn budget" and an even smaller fraction of Elon Musk's SpaceX project "valued at around $100bn". The creation of an interstellar object interceptor mission would be more expensive and was estimated to cost $1bn. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/The_Galileo_Project-2.md b/data/en.wikipedia.org/wiki/The_Galileo_Project-2.md new file mode 100644 index 000000000..6cbdb5896 --- /dev/null +++ b/data/en.wikipedia.org/wiki/The_Galileo_Project-2.md @@ -0,0 +1,26 @@ +--- +title: "The Galileo Project" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/The_Galileo_Project" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T13:16:19.736412+00:00" +instance: "kb-cron" +--- + +== Reception and impact == +The project gained substantial mainstream media coverage, was applauded by many, including scientists, and gained traction on social media and in online communities of people interested in UFOs. An NBC News article describes the project as "exactly the kind of research many have called for after the release of the Pentagon's intelligence report in June [2021]". +There have also been various concerns, doubts and criticism about the prospects of the Galileo Project. +Some astronomers are worried that astronomy and the search for extraterrestrial intelligence (SETI) are getting undermined by projects like the Galileo Project. Senior astronomer for the SETI Institute, Seth Shostak has compared his organization's and broader UFO-unrelated SETI efforts with Loeb's project, describing his preferred approach as "studying unknown fauna in the rainforest", and the latter's search for aliens in Earth's atmosphere as "hoping to find mermaids or unicorns". However, Shostak also stated that Loeb's "peers" (i.e. the academic astronomical community) "should be grateful for [Loeb's] effort," and that he is "grateful that [Loeb] has the freedom—and the guts—to go where few would dare to go". +Some astronomers have also criticized claims by the project's lead scientist for "insufficient" evidence to "support his bold conjectures about alien life". Astrobiologist Caleb Scharf stated that the Galileo Project has "intermingled legitimate scientists with" what he assessed to be fringe people. Nonetheless, on August 24, 2023, The New York Times published an article about Loeb and his related search for signs of extraterrestrial life and The Galileo Project. + +== See also == +Technosignature +Fermi paradox +Ufology#Research +Search for extraterrestrial intelligence + +== References == + +== External links == +Official website \ No newline at end of file