As feared, the 740 tonne instrument platform collapsed yesterday at the Arecibo Observatory in Puerto Rico, falling onto the gigantic radar dish below. Photos of the scene are revealing the extent of the damage at the famous facility, which is known for contributing to the search for extraterrestrial intelligence and numerous astronomical discoveries.
The collapse occurred at around 7:55 a.m. local time, as the receiving platform plunged 140 metres down to the 305 metre dish below, which had already been damaged in recent months by fallen cables. No injuries were reported, but the collapse has caused considerable damage to the radar dish and surrounding facilities, including a learning centre, according to the U.S. National Science Foundation.
With the platform gone, Arecibo looks very different
The full extent of the damage is still being assessed. The area continues to be off limits to unauthorised personnel, while engineers are evaluating the stability of the remaining structures, such as the LIDAR facility used to study the upper atmosphere. Recovery teams are also currently working to mitigate potential environmental damage caused by the collapse. Here’s how the facility looked in 2019, before this year’s cable failures:
A ‘heartbreaking’ sight
“We knew this was a possibility, but it is still heartbreaking to see,” Elizabeth Klonoff, vice president for research at the University of Central Florida, which manages the facility for the NSF, told UCF Today.
The 816 T instrument platform fell onto the dish below and can be seen lying on the side of the structure. It appears that the platform did not fall straight down but swung at an angle, which makes sense, given that a failed wire from one of the three support towers triggered the collapse.
The towers still stand — but without their tops
A preliminary assessment of the scene shows that the tops of all three platforms were sheared off as a result of the structural breakdown and that falling debris, including the support wires, landed outside the area of the dish. The learning centre located near Tower 12 appears to have sustained “significant damage,” according to the NSF. That all three support towers are still standing is fortunate, as it was feared a collapse of the towers would damage buildings nearby.
Twisted metal and a cracked dome
This is a particularly painful view of the damage, showing the mangled instrument platform, the busted Gregorian Dome (a multi-beam receiver capable of scanning multiple points in the sky at once), and the fallen support cables, which sliced through the dish like knives. The cause of the collapse is still under investigation, but as NSF officials pointed out during a press conference held on November 19, the cables did not perform as expected, possibly on account of exposure to excessive moisture. A forensic investigation of the cables is still ongoing, and we eagerly await the results.
The ground view
The view from the ground is not much better, showing the destruction in detail.
Unplanned but not unexpected
The collapse of the instrument platform on December 1 was not a surprise. The famous radar dish was recently slated for controlled demolition following a series of cable failures. An auxiliary cable slipped from its socket in August, and a main cable snapped in early November due to the added strain. Engineers said the structure was at risk of imminent collapse and that it would be too dangerous for workers to attempt repairs. Monday’s unplanned collapse was not ideal, as officials were hoping to preserve scientific and educational infrastructure at the facility. Arecibo hosts 90,000 visitors each year.
Arecibo before the collapse
For context, here’s what the radar dish looked like on November 19, 2020, following two cable failures.
The end of an era?
Completed in 1963, the Arecibo Observatory contributed to a host of astronomical discoveries. The dish was used to detect the very first exoplanets and the first binary pulsar (which resulted in a Nobel Prize in physics), and it famously transmitted a message to aliens. The radio telescope was also used to study planets and nearby asteroids and to assist in the search for extraterrestrial intelligence (SETI). The loss of the dish is a major blow to the scientific community (particularly those working in Puerto Rico), as it was the second largest radio dish in the world. No word yet on whether the dish will ever be replaced, but it’s a conversation that’s already starting.