The world’s most famous radio telescope, the 305-metre Arecibo dish nestled in the rough karst of Puerto Rico, has been irrecoverably destroyed . The U.S.’s National Science Foundation (NSF) made the grim announcement Thursday. Arecibo has played a role in innumerable fundamental discoveries in astronomy, and at every imaginable scale. Initially built to detect the radar signatures of missiles re-entering the atmosphere, it has added to our knowledge of planets, comets, galaxies, pulsars, quasars, neutron stars, dwarf stars … literally every celestial object that there is a name for, and some that perhaps don’t have one.
Arecibo is ubiquitous in pop culture, but might be most famous for sending the half-whimsical and slightly controversial “Arecibo message” of 1974, a bitmap image intended to give aliens some hints to humans’ appearance, location and intelligence. Up until its demise, the telescope remained Earth’s busiest workhorse for the imaging of asteroids and other near-Earth objects, including ones labelled Potentially Hazardous Objects (PHOs). ( NASA pointed out in a Thursday statement that these objects and their trajectories are normally discovered by optical telescopes first, so overall planetary defence won’t be compromised.)
The Arecibo telescope consists of a giant spherical reflector, surfaced in aluminum, and a movable receiver mounted 150 metres above the dish. The receiver is held aloft by 18 cables attached to three concrete towers at the circumference of the dish. An auxiliary cable failed in August, and although early analysis showed that the load on the remaining cables was well below their rated failure point, a main cable unexpectedly gave way on Nov. 6.
Arecibo is ubiquitous in pop culture
Engineers and fresh cables were dispatched to the site, but the investigators, backed by the Army Corps of Engineers, quickly concluded that repairs are impossible to make safely . Even demolition, the only choice remaining, will be difficult and risky.
Arecibo is rather reminiscent of other great monuments to modernism; it looks like nothing so much as a domed sports stadium turned upside-down and thrust into the earth, and indeed it shares some of the failings of the Astrodome in Houston or Toronto’s SkyDome (now known as the Rogers Centre). Its versatility has made it possible for it to be superseded in some respects by other, more affordable facilities, and its large scale and innovative design have made it expensive for the NSF to operate. The fixed-reflector design has inspired many other telescopes, and the Chinese completed a 500-metre Arecibo-like device this year, but the state of the art in radio telescopy is now represented by synchronized arrays of interferometers such as the Very Large Array in New Mexico.
Because of its use in imaging planets and asteroids, it might seem natural for the telescope to belong to NASA, which has the responsibility for near-Earth objects. But in the past, when Arecibo budget cuts were being considered by NSF and NASA was badgered for help, NASA’s biting answer was literally “We haven’t asked NSF to operate any of our spacecraft.”
Whether the telescope died of bureaucratic neglect is a question that will now come before the public and Congress. NASA did eventually come across with some money, but the NSF remained explicitly eager to reduce or offload Arecibo’s costs, although the telescope has never at any moment been considered obsolete. In 2018 a plan was devised to allow a consortium of universities to contribute to its upkeep. But hurricanes and earthquakes kept inflicting insults on the dish and the receiver, and the cabling system, designed in the early ’60s, may simply never have been destined for permanence.
One likely outcome of the disaster will be to provide greater impetus to the international Square Kilometre Array project, the 21st century’s answer to Arecibo. The SKA, which has 13 participating countries but doesn’t formally include the U.S., will consist of thousands of telescopes scattered around the Southern Hemisphere, with large concentrations of arrays located in South Africa and Australia.
Progress toward construction has been halting, and the whole array is not expected to come into service before 2027. SKA faces NIMBY problems, since it requires enormous areas of wilderness to be kept free of all RF-emitting devices, and there are challenges with data capture. SKA can image so much of the sky that supercomputers have to be involved, but China is a key partner, creating legal barriers to tech-sharing.
The U.S. might consider giving the SKA some love, and it could also reinvest in the Allen Telescope Array in Shasta County, a largely private project focused on searching for extraterrestrial life. (The name comes from its original benefactor, Microsoft zillionaire Paul Allen.) Like Arecibo, the ATA has potential well beyond its initial purpose, and improving radio telescopy can depend more on software and sophisticated error correction than on elbow grease and engineering megastructures.
That’s part of the heartbreak of losing Arecibo. It’s a beautiful artifact from a time when heroic physical scale was the only avenue for extending the human sensory apparatus, now so dependent on the teeming of digital automata. One thinks with sorrow how wonderful it would be if we could still visit the island of Hven and tour Tycho Brahe’s Uraniborg, the place where astrology and alchemy merged into the form of the modern multidisciplinary laboratory. We regret that it was allowed to fall into ruin while repeating the crime ourselves.
The destruction of the Arecibo telescope is also a tragedy for Puerto Rico, following, as it does, a series of unspeakable natural disasters. The commonwealth, so often the U.S.’s ill-treated stepchild, could always point to the telescope as a sign that its pact with the American military-industrial complex brought meaningful benefits. Arecibo was an important tourist attraction and an inspiration to every Puerto Rican kid with an interest in hard science — even, indeed, the Puerto Rican kids who lived elsewhere in the United States.
The scientific work of Arecibo can, with time, be distributed to other telescopes, to Earth-orbit satellites, and perhaps even the surfaces of other celestial bodies. But there is no possibility of comfort for the Arecibeños who have lived proudly between its vast bowl and the sea.
Copyright Postmedia Network Inc., 2020