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As feared, the 740-ton instrument platform collapsed yesterday at the Arecibo Observatory in Puerto Rico, falling on the giant radar dish below. Photos of the scene are revealing the extent of damage to the famous structure, known for contributing to the search for extraterrestrial intelligence and numerous astronomical discoveries.
The collapse occurred around 7:55 am local time, when the receiving platform plummeted 140 meters to the 305-meter antenna below, which had already been damaged in recent months by fallen cables. No injuries were reported, but the collapse caused considerable damage to the radar antenna and surrounding structures, including a learning center, according to the US National Science Foundation.
With the platform gone, Arecibo looks very different
An aerial view of the Arecibo Observatory after the December 1, 2020 collapse (Image: Ricardo Arduengo / AFP via Getty Images, Getty Images)
The extent of the damage is still being assessed. The area continues to be closed to unauthorized personnel, while technicians are evaluating the stability of the remaining structures, such as the LIDAR structure used for the study of the upper atmosphere. Recovery teams are also working to mitigate the potential environmental damage caused by the collapse. Here’s what the facility looked like in 2019, ahead of this year’s cable failures:
Arecibo Observatory in the spring of 2019, before the cable broke and collapsed. (Photo: UCF today)
A “heartbreaking” sight
Aerial view showing extensive damage to the large radar dish as well as the location of the fallen instrument platform. The collapse also ripped off the tops of the three support towers. (Image: Ricardo Arduengo / AFP via Getty Images, Getty Images)
“We knew this was a possibility, but it’s still heartbreaking to see,” Elizabeth Klonoff, vice president of research at the University of Central Florida, who manages the facility for NSF, told UCF Today.
The platform of the 816 T instrument has fallen onto the dish below and can be seen lying on the side of the structure. It appears that the platform did not fall directly down, but swung at an angle, which makes sense, as a broken wire from one of the three support towers triggered the collapse.
The towers are still standing, but without their tops
An expansive aerial view of the facility on December 1, 2020 (Image: Ricardo Arduengo / AFP via Getty Images, Getty Images)
A preliminary assessment of the scene shows that the tops of all three platforms were sheared due to structural failure and that falling debris, including support cables, landed outside the area of the dish. The learning center located near Tower 12 appears to have suffered “significant damage,” according to the NSF. That all three support towers are still standing is fortunate, as it was feared that a collapse of the towers would damage nearby buildings.
Twisted metal and cracked dome
Aerial view showing the fallen platform, the Gregorian dome and the supporting cables. (Image: Ricardo Arduengo / AFP via Getty Images, Getty Images)
This is a particularly painful view of the damage, showing the mangled instrument platform, the broken Gregorian dome (a multi-beam receiver capable of scanning multiple points in the sky at once), and the fallen support cables, which cut the platter as knives. The cause of the collapse is still under investigation, but as NSF officials pointed out during a press conference held on Nov.19, the cables did not perform as expected, possibly due to exposure to excessive moisture. A forensic investigation into the cables is still ongoing and we eagerly await the results.
The view from the ground
Damage seen on the ground. (Image: UCF Today)
The view from the ground isn’t much better, showing the destruction in detail.
Not planned but not unexpected
Aerial view of the Arecibo Observatory on 1 December 2020 (Image: Ricardo Arduengo / AFP via Getty Images, Getty Images)
The collapse of the tools platform on December 1 was no surprise. The famous radar dish was recently scheduled 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 additional tension. Engineers said the facility was in danger of impending collapse and that it would be too dangerous for workers to attempt repairs. The unplanned collapse on Monday was not ideal, as officials hoped to preserve the science and education infrastructure at the facility. Arecibo hosts 90,000 visitors every year.
Arecibo before the collapse
Arecibo as it appeared on November 19, 2020. Previous cable failures have caused visible cuts in the dish. (Image: Ricardo Arduengo / AFP via Getty Images, Getty Images)
For context, here’s what the radar antenna looked like on November 19, 2020, following two cable failures.
The end of an era?
A motorcyclist drives by a road sign towards the Arecibo Observatory on December 1, 2020. (Image: Ricardo Arduengo / AFP via Getty Images, Getty Images)
Completed in 1963, the Arecibo Observatory contributed to a number of astronomical discoveries. The dish was used to detect the very first exoplanets and the first binary pulsar (which led to a Nobel Prize in physics), and famously sent a message to aliens. The radio telescope has also been used to study nearby planets and asteroids and to assist in the search for extraterrestrial intelligence (SETI). The loss of the dish is a severe blow to the scientific community (especially those working in Puerto Rico), as it was the second largest radio dish in the world. It is not yet known if the plate will ever be replaced, but it is already a conversation that is starting.
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