Scientists reflect on the large doomed plate of Arecibo

The large platter of the Arecibo Observatory in Puerto Rico is on the brink of collapse, leaving officials with no choice but to pick up the famous radio telescope. Astronomers around the world are now facing a sad reality: that this dutiful dish – in service for 57 years – no longer exists.

I have to admit, the thought that the 305-meter antenna at Arecibo should be shot down never occurred to me when I started covering this story over the summer. The first disturbing development occurred on August 10, when an auxiliary cable slipped out of its socket, crashing through the dish below. The fall of the cable created an unsightly 30.48m scar, but at the time the accident seemed more of a nuisance than a catastrophic problem. And indeed, observatory officials soon made arrangements to repair the damage and replace the missing cable.

Things took a turn for the worse on November 6, when a main cable snapped and it too fell on the structure. This was where I really started to worry. A missing auxiliary cable is one thing, but a missing auxiliary cable is a main cable? Not well. In my mind, I imagined the 816 T platform, suspended 137 meters above the dish, held together by a rope. A new image of a worn-out cable didn’t relieve my anxiety.

I contacted the Arecibo Observatory, the National Science Foundation, and the University of Central Florida, which manages the facility on behalf of the NSF. On the morning of Thursday November 19th, I woke up to an email from NSF alerting me to a press conference that would be held later that morning. Finally, I thought, I would be able to report on pending repairs and a strategy to bring the besieged facility back online. After registering for the press conference, however, NSF sent me more details: the iconic dish had to be scrapped.

It felt like a punch in the stomach.

Engineering teams intervening to assess the situation said the platform could suffer catastrophic collapse at any time, making it dangerous for workers. The antenna, in operation since 1963, would have had to undergo a controlled dismantling in order to preserve other assets in Arecibo, including a LIDAR facility and a visitor center.

While the scientific work at the Arecibo Observatory will continue, the radio parabola is finished. And this is a huge shame. In addition to its cultural significance, the dish has promoted some excellent sciences, including the first detection of a binary pulsar (which earned the team a Nobel Prize in physics), the first radar maps of Venus, the detection of potentially dangerous asteroids. , the first ever discovered exoplanets and information on gravitational waves. The facility was also used to transmit a message to aliens and, of course, to search for rebel radio signals sent by extraterrestrial intelligences.

Sad for the big pot’s recall, I reached out to scientists to get their thoughts on the news. One person I absolutely had to contact was Jill Tarter, an astronomer and SETI scientist. Tarter, as some of you may know, inspired Jodi Foster’s character in the 1997 film Contact (if you haven’t seen this movie, now would be a good time to watch it, as it features the Arecibo Observatory). Here’s what he had to say:

I’ve been going to Arecibo since 1978. Over the decades we’ve built a lot of Arecibo-specific hardware, written a lot of software, and adapted the telescope control system to ways it was never designed for. Arecibo was an impressive feat of engineering, a scientific workhorse, and it never lost that aura of being a bit exotic no matter how many times I visited; the constant croaking of the coquis, the scents of the tropical forest, the local Ron del Barrilito, the Gregorian dome with its unmistakable compressor cadence, the jogging track under the plate ringed with small orchids, Orion rising on the treetops seen from the balcony of the VSQ [lodging rooms for visiting scientists], before leaving for my midnight shift on the Phoenix Project [a search for extraterrestrial intelligence] observations and the absolutely best view of the island from the top of the platform. But most of all, I remember the resident staff and scientists who were very close, gave us excellent technical support and threw wonderful parties with lots of dancing.

It is very sad to see the death of this scientific queen. It has withstood powerful hurricanes, but age seems to have taken over.

Hurricanes, yes, but also earthquakes.

I wrote to Avi Loeb, a science professor at Harvard University and the longest-serving president of his department of astronomy. He answered:

Apparently, I visited Arecibo with my family and held a seminar there in summer 2016. We took a special tour of the facility where we were told that, thanks to a numerical error relating to the observatory’s initial purpose, the design ended with a 305-meter telescope, the largest radio telescope in many decades. It took about a decade to get the calibration correct and bring the dish to its full operational capacity.

The NSF’s decision to deactivate Arecibo implies a great loss for radio astronomy. The astronomy community in the United States should come up with a new plan on how to maintain our leadership in radio astronomy. Without Arecibo, the largest radio dish on Earth is the Chinese Tianyan Telescope (FAST), which has a diameter of 500 meters.

Anne Virkki, radar scientist at the Arecibo Observatory, described how the loss of the telescope will affect both science and Puerto Rico:

The Arecibo Observatory has 57 years of scientific breakthroughs in several scientific branches (astronomy, planetary science, and space and atmospheric science), including one that led to the Nobel Prize in Physics. Just before the first cable fell, we observed an asteroid called 2020 NK1 that had a relatively high probability of impact, and that observation allowed NASA to determine that it poses no risk after all. The observatory has helped hundreds, if not thousands of students at different stages of their academic journey and has inspired millions of people simply by existing. To everyone who worked on it, it left the feeling of being part of something big. Although the telescope’s support cables are compromised, it is neither scientifically obsolete nor an instrument replaceable by the other existing radio telescopes in the world. And it will leave an immense hole in all Puerto Ricans, in their national pride, in educational opportunities and, in some cases, in their wallets, as it has actively contributed to the (already degrading) Puerto Rican economy for decades.

Virkki also shared his thoughts as a private citizen, not as a representative of the Arecibo Observatory, an employee of UCF or any other affiliated company or agency:

This is a much bigger loss than any federal funding agency dares to admit. The Goldstone Solar System Radar will not be able to detect what the Arecibo Observatory could do. To me personally, it feels more like a home than a workplace, and the NSF’s decision to demolish it feels like a big company wants to demolish the house you grew up in to build a highway over it. Demolishing it was never the only option.

Incidentally, Virkki had plans to use the Arecibo dish to study Apophis, a potentially dangerous asteroid that will somehow approach Earth next year and an exceptionally close approach in 2029. It won’t happen now, but more radio observers will be. ready.

Andrew Siemion, astrophysicist and director of the Berkeley SETI Research Center, also shared his thoughts:

It is difficult to overstate the role Arecibo has played in SETI research, being a singular resource in major SETI observation campaigns, including Project Phoenix, Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations (SERENDIP) and [email protected], which serves as a vehicle for multiple interstellar messaging activities, including the Arecibo Message, and serves as a canonical reference point for the detectability of terrestrial communication systems through its planetary radar. Alongside the strength of Arecibo as a research tool, it has also had a huge impact on the popular conception of SETI, including countless appearances in documentaries, books and films, including Contact. Arecibo has also nurtured the radio astronomy community during its nearly sixty-year career, serving as a training ground for hundreds of radio astronomy students. It is worth pointing out that some professional observers are quite conservative when it comes to allowing students to work directly on the instrumentation, but Arecibo has always had a welcoming and cooperative attitude towards students or anyone else who has a “crazy idea”. This overall philosophy has been a huge part of its success and its significance to the SETI community.

Of all the radio telescopes I’ve ever visited, and I’ve visited a few, Arecibo stands out as a magically surreal symbol of human ingenuity and exploration. The journey to the telescope, which winds its way through narrow jungle roads and then arrives at the gate and access road is quite odd. But the journey to the control building, during which the telescope remains hidden from view, and then the walk into the observer’s console where huge windows open onto a panorama of this incredible structure nestled in the foliage is simply … indescribable . I think I’m very sad for the many future students, explorers … humans, who won’t have the chance to make that incredible journey.

Victoria Kaspi, an astrophysicist at McGill University in Montreal who studies pulsars (rapidly rotating stars that emit beams of electromagnetic radiation from their magnetic poles), said she was still “incredulous” about the whole situation:

Arecibo has been absolutely crucial to pulsar astrophysics for the past 40+ years. Already celebrated by the Nobel Prize for the discovery of the first binary pulsar and the subsequent fundamental test of Einstein’s theory of general relativity, Arecibo has done much more for our understanding of the galactic pulsar population. My colleagues, students, and I have used it to discover hundreds of pulsars over the past decade, including recently the most relativistic binary pulsar system known to date, totally unexpected sources such as millisecond eccentric binary pulsars, and a system that helps to understand puzzles. raised by gravity wave sources detected by aLIGO [advanced Laser Interferometer Gravitational-Wave Observatory]. In fact, just days before the announcement of the NSF decommissioning, my PhD student Emilie Parent discovered a ton of new pulsars in our Arecibo data! Even up until its final moments of operation, Arecibo was still a phenomenal and unique open machine, which is what makes this turn of events so frustrating.

During the November 19 press conference, I asked NSF officials if they are committed to building a new radar dish in Arecibo, perhaps even better than the original. Understandably, they couldn’t commit right now, as the priority now is to safely disable the dish. One thing they have made clear, however, is that they are not leaving the Arecibo Observatory entirely and that we can expect exciting science for years to come.

My hope now is that scientists, students and anyone else with an interest in radio astronomy will work together to make this happen: to see a new dish installed at Arecibo. Let’s turn this setback into an opportunity – this story isn’t over yet.