Goodbye Arecibo
By: Julian Sitkevich
Tags: Astronomy, Science, Technology, Space

The Arecibo radio telescope is no more.

Title: Starry sky above Arecibo Observatory — Credit: University of Central Florida

On Dec. 1 2020 at Arecibo Observatory, after a critical support cable snapped, the 900-ton platform crashed into the thousand-foot diameter reflective dish below, destroying the legendary 57-year-old radio telescope once and for all. No one was hurt.

Previous to the final cable failure, the Arecibo Observatory was scheduled to be decommissioned after two critical cables failed which supported the “line feed” platform above the main dish. The structural issues began on Aug. 10 when one of Tower 4's auxiliary cables popped out of its anchor, ripping through the dish below. The University of Central Florida hired three engineering firms to asses the situation.

Then on Nov. 6, the second failure occurred, one of the main cables supporting the platform failed, and shortly thereafter the N.S.F. announced it would be decommissioning the telescope due to the assessment the telescope was in danger of catastrophic failure, and could no longer be safely repaired. This was not the outcome anyone had hoped. The disappointment can be heard in a quote from UCF President Alexander N. Cartwright:

“Our team has worked tirelessly with the NSF looking for ways to stabilize the telescope with minimal risk” “While this outcome is not what we had been working towards, and we are disheartened to see such an important scientific resource decommissioned, safety is our top priority. At a time when public interest and scientific curiosity about space and the skies has re-intensified, there remains much to understand about the data that has been acquired by Arecibo. Despite this disappointing setback, we remain committed to the scientific mission in Arecibo and to the local community.”

After the decommissioning announcement, a hashtag had sprouted up, #WhatAreciboMeansToMe with heartwarming tweets and images about the observatory.

Then on Dec. 1, the inevitable final straw happened, the last supporting platform cable failed, destroying the telescope forever.

Humble Beginnings

The Arecibo radio telescope was the largest single-dish radio telescope ever created, up until the completion of China’s 500-meter Aperture Spherical Radio Telescope (FAST) in 2016.

The idea for Arecibo Observatory was born of William E. Gordon, a Cornell University professor who wanted to study the ionosphere, Earth’s upper atmosphere, by using radar. He also served as AO’s first Director through 1965.

The area was chosen in Puerto Rico due to it’s natural limestone sinkhole, making a perfect fit for the massive dish, and being close to the equator, allowed the telescope to have a near continual wide angle view of the universe above.

Discoveries

Arecibo Observatory had made important achievements and discoveries in astronomy over its five-plus decades in existence, including:

Mercury’s rotation rate is 59 days, not the previous value of 88 days (1967)

Created the first radar scans and maps of the surface of Venus (1981)

Discovered the first ever exoplanet around pulsar PSR 1257+12 (1992)

Then the last discovery (2017), two unusual pulsars which overturned the idea that pulsars are the reliable ticking clocks of the universe

Popular Culture

Arecibo has been burned into the collective consciousness of popular culture, featured in Carl Sagan’s Contact novel and later movie adaption, featuring Jodie Foster playing the real life scientist Jill Tarter. The telescope was also featured in the James Bond film GoldenEye and in the TV-Series The X-Files.