The Arecibo Telescope in Puerta Rico suffered a dramatic collapse yesterday, December 1, months after it suffered severe damage when a main cable broke, and just weeks after the National Science Foundation (NSF) opted to decommission the iconic observatory. The news has come as a blow to the scientific community and the telescope's fans, with many commenting on how sad an end this is to the incredible instrument.

For 53 years, it was the largest single-aperture radio telescope in the world. It had a diameter of 304.8 meters (1,000 feet), but was surpassed by the Five-hundred-meter Aperture Spherical Telescope (FAST) in China in July 2016.  Over its illustrious career, the telescope developed revolutionary scientific discoveries as well as famously featuring in movies such as Contact and Goldeneye.

New drone footage below (released on Thursday) shows the moment that the cables and then Arecibo finally collapsed. 

^{Click expand to see it in full-screen.}

 

From the get-go, the telescope was revolutionary. Just a few months into operation in April 1964, it was used to determine the rotation of Mercury, which was unknown at the time. In 1992 it was used to discover water ice in some of the planet’s north pole crater. Arecibo also dramatically expanded our knowledge of asteroids, including some of the ones that may impact Earth.

The telescope has also been crucial in our study of pulsars, a special type of neutron star, discovered in 1967 by Dr Jocelyn Bell Burnell. These extreme objects, the result of a supernova, pulsate at regular intervals, and in 1968 Arecibo discovered one of these objects, pulsating every 33 milliseconds at the heart of the Crab Nebula. 

Just a few years later, in 1974, astronomers Russell Hulse and Joseph Taylor Jr discovered the first pulsar in a binary system. The regular pulsation was used to establish the properties of the system as a cosmic clock of sorts. They were able to confirm a crucial prediction of Einstein’s theory of general relativity. The orbit of the system was shrinking due to the emission of gravitational waves. They won the Nobel Prize in Physics for this work in 1993.

In 1992, Arecibo was responsible for the first discovery of planets beyond the Solar System, which were found orbiting a pulsar. It was also a lifeline for the joint European Space Agency and NASA Solar and Heliospheric Observatory (SOHO) spacecraft. When ground stations lost contact with the spacecraft in 1998, it was the work of scientists at Arecibo that allowed it to be located. SOHO continues to work today.

^{Drone footage shows the latest collapse as of December 1, 2020.}

Its later years continued to bring forth incredible discoveries. In 2007, its observations led to the discovery of hydrogen cyanide (HCN) and the presence of the molecule methenamine (CH2NH) in Arp 220, a galaxy 250 million light-years from us. These are considered pre-biotic molecules, important as they could form the building blocks of life.

In fact, Aricebo has been crucial for the search for alien life throughout its career. Its data has long been used by the SETI Institute (Search for Extra-Terrestrial Intelligence). In 1974, it was used to send the most powerful broadcast ever beamed into space, a message sent to globular star cluster M13. Devised by Frank Drake (of the Drake Equation fame), the Arecibo Message, written by Drake and Carl Sagan among others, was a technology demonstration to see if we could communicate with other beings in the universe.

The telescope was also responsible for detecting Fast Radio Burst FRB 121102, the first repeating FRB ever discovered, and a game-changer in the field. 

These are just some of the highlights among 57 years of incredible discoveries thanks to the historic observatory, the people employed there, and the researchers that got to use its data. The scientific community mourns the loss of such an instrument; some have even petitioned the NSF to keep it open. However, the damage to its telescope is too much, and it will be demolished to save the lidar facility, visitor and education center, which serves as a hub for STEM education and outreach.