Just two weeks ago, the National Science Foundation (NSF) made the sad decision to permanently close the National Astronomy and Ionosphere Center in Arecibo, Puerto Rico, after damage to the 1,000-foot-wide instrument rendered it unstable to even inspect, much less operate. The damage resulted from the failure of two cables that supported portions of the enormous instrument, placing the remaining cables under high tension and generating a risk that the entire structure could fail at any time.
That’s exactly what happened early on Monday evening. It appears that the remaining cables failed in a cascade, causing the entire dish to collapse, and bringing to an end any hope of saving an instrument that has literally helped to see back to the origins of the universe.
Made famous by its appearance in films like Contact and television shows like The X-Files, Arecibo was a star even when not on the screen. The facility was originally planned as part of an anti-ballistic missile defense system in the 1950s, but the giant fixed dish was poorly suited to that task and it swiftly moved to use in a scientific setting. The design of the facility, which unlike smaller radio telescopes could not tilt toward other areas of the sky, limited its use in some areas of radio astronomy, but a series of clever upgrades provided more flexibility as well as helping to protect the instrument from the passage of storms and hurricanes. If the inability to move meant that there were some things the Arecibo instrument could not do, its sheer size made it a force in other areas. It was, for decades, the largest such dish on the planet.
It helped investigate distant interstellar objects as well as providing details about the Earth’s own atmosphere and radiation belts. It was also well known for its association with Search for Extraterrestrial Intelligence (SETI) and was used in an effort to both detect and send messages. In 1974, “the Arecibo message”—a binary pattern that included a set of numbers, chemical formula, and stick figures of a human—was sent from the dish toward a group of stars a staggering 25,000 light-years away. Among other discoveries, Arecibo Observatory was instrumental in detecting the first planets found outside our own solar system as well as the first neutron stars. Within our own system, the instrument was the first to sort out the correct rotational period of Mercury.
The giant telescope helped bring leading scientists to Puerto Rico and was a source of both pride and income for local communities—though the funding for the observatory was never a sure thing. The NSF always provided the bulk of the funding, but for three decades NASA also played a role in providing funding as the dish became part of a network to locate and track near-Earth asteroids. After 2006, NSF sharply reduced funding and the Arecibo Observatory was repeatedly threatened with closure. A series of operating consortiums were established to upgrade and promote the Arecibo instrument, and the government of Puerto Rico also contributed to keeping the observatory up and running. However, as NSF funds diminished, much of the other income went to simply maintaining the facility. Despite academic pleas, dollars to operate the instrument became increasingly scarce.
In 2017, Hurricane Maria passed directly over the area, causing communication cables to snap and fall into the dish, damaging part of the instrument. The scope of the damage was relatively small … but was large compared to the observatory’s vanishing budget. When a first cable broke in August 2020, a repair was organized and a new cable purchased. However, before it could be installed, a second cable snapped on Nov. 7, paralyzing repairs while engineers hoped to work out a safe approach. Finally, NSF concluded that there was no way to save the existing instrument and began the process of decommissioning the observatory.
With the collapse of the dish, it’s not certain what will happen now. It’s not clear that such a large, fixed instrument has a place in the current research budget—though China has recently completed an even larger dish that it hopes to use in the search for dark matter. What is certain is that the Arecibo Observatory was an iconic instrument that provided serious contributions to science over a period of decades. What’s left in its place should be something worthy of that legacy.