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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Arecibo Telescope | 5/6 | https://en.wikipedia.org/wiki/Arecibo_Telescope | reference | science, encyclopedia | 2026-05-05T13:15:38.928164+00:00 | 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 ===