kb/data/en.wikipedia.org/wiki/Active_SETI-2.md

title	chunk	source	category	tags	date_saved	instance
Active SETI	3/3	https://en.wikipedia.org/wiki/Active_SETI	reference	science, encyclopedia	2026-05-05T13:15:29.258655+00:00	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