The road to Arecibo Observatory in northwestern Puerto Rico winds upward through farms and rainforest. Chickens run across the road. Then, suddenly, you reach the top: a fence, guards and gleaming white buildings and towers, as if you had stumbled into the lair of a James Bond supervillain.
Hanging in the sky like a skeletal flying saucer, suspended by cables from three mountaintop towers, is a giant triangular structure of girders. Five hundred vertiginous feet below, nestled in a sinkhole valley, is an aluminum dish 1,000 feet wide — an antenna to catch radio waves from the cosmos or to beam them out.
In early August, hearts sank throughout the universe when news surfaced that a falling cable had ripped a 100-foot-long gash in that antenna, temporarily putting it out of commission. For more than half a century, the Arecibo telescope has been one of the great icons of interstellar longing.
Built in 1963, it served as the flagship for the search for extraterrestrial intelligence, or SETI, the optimistic quest for radio signals from alien civilizations. In 1974, astronomers sent their own message out into the void, toward a cluster of stars known as Messier 13. (Travel time is 25,000 years, so we should not expect a reply for at least 50,000.)
Astronomers used the observatory to map dangerous asteroids as they buzzed past Earth, and to measure the rotation rate of Mercury. Employing the antenna’s exquisite sensitivity, they tuned in to the enigmatic clockwork blips of distant pulsars, discerning in their changing rhythms secrets of unworldly physics. For years the National Astronomy and Ionosphere Center, as the observatory is officially known, hosted the largest single radio antenna on the planet, only surpassed in 2016 by a new telescope in China that is 1,600 feet in diameter.
“It is a remarkable scientific instrument, so emblematic of our self-confident years in science,” said Michael Turner, a cosmologist now at the Kavli Foundation and former assistant director of the National Science Foundation, in an email. “So remarkable that the Chinese copied it!”
On the morning of Aug. 10, a cable that helped support the triangular structure that holds the antenna’s radio receivers snapped and crashed through the antenna. About 250 of the 38,778 aluminum panels that make up the dish were damaged. No one was hurt.
Arecibo’s director, Francisco Córdova of the University of Central Florida, and Ramon Lugo, director of the university’s Florida Space Institute and principal investigator for the observatory, reported in a Zoom news conference a few days later that nobody knew yet why the cable, which was more than three inches thick, had snapped. It had been installed in the 1990s to bolster a support for a new addition to the 900-ton instrument platform and was expected to last another 15 to 20 years, Dr. Cardoza said.
Nor did the two researchers know how long it would take to repair the damage, or how much it would cost. Fabricating and shipping a new cable could take months, Dr. Lugo said.
The loss of a few hundred panels was no big deal, Dr. Córdova said. The bigger issue is making sure the instrument platform is structurally stable. “We’ve been tested before,” Dr. Córdova said, alluding to a long history of mishaps and crises, including earthquakes, Hurricane Maria in 2017 and now the Covid-19 pandemic. “This is just another bump in the road.”
The Arecibo facility was originally built and run by Cornell University under contract to the Air Force Research Laboratory, partly out of a desire to understand the properties of objects like nuclear warheads tumbling through the upper atmosphere. As a result, it was built to be both a telescope and a planetary radar.
One of its directors over the years was astronomer Frank Drake. He was famous for first pointing a radio telescope at another star for indications of friendly aliens, then for an equation, still in use today, that tries to predict how many of “them” are out there.
On Nov. 16, 1974, Dr. Drake beamed the equivalent of a 20-trillion-watt message toward M13, a cloud of about 300,000 stars some 25,000 light-years from Earth, as part of a celebration of an upgrade to the antenna.
The message consisted of 1,679 zeros and ones. Arranged in 73 rows and 23 columns, the bits formed pictures of a stick man, the radio telescope, a DNA helix, the solar system, the numbers 1 through 10 and more. Before Dr. Drake sent it off, he tried out the message on his Cornell colleagues, including Carl Sagan, the author and proselytizer of the search for life in the cosmos. None of them could decode all of it.
Maybe E.T. would be smarter when the signal finally reached somewhere, but the real point of such messages, Dr. Drake and Dr. Sagan always admitted, was to raise the consciousness of those of us back here on Earth and an awareness of our own status as cosmic travelers in an unknown and obviously weird universe.
The feat was repeated in November 2009 when Joe Davis, a self-described “bio-artist” in residence at the Massachusetts Institute of Technology, hooked his smartphone to the Arecibo telescope and sent the genetic code for RuBisCO — ribulose-1,5-bisphosphate carboxylase/oxygenase, a common plant protein — in the direction of three nearby stars.
In 1974, the same year that the first SETI message was sent, astronomers Joseph Taylor and Russell Hulse, both now at Princeton, used the Arecibo telescope to discover a pair of pulsars orbiting each other. By timing the pulses over several years, the astronomers determined that the system was losing energy at the exact rate it would if the pulsars were radiating gravitational waves — the ripples in space-time that Einstein predicted to exist but which were not directly detected until 2016, by the LIGO gravitational wave observatories. In 1993 Dr. Taylor and Dr. Hulse won the Nobel Prize in Physics for their observation.
In 1990 a Polish astronomer, Aleksander Wolszczan, made another landmark discovery with Arecibo: PSR B1257+12, a pulsar with an irregular heartbeat. Further investigation revealed that the pulsar was orbited by three planets — the first planets ever discovered orbiting a star other than the sun. Today hundreds of such exoplanets are known, and their study is the fastest-growing field in astronomy.
The observatory has cemented a place in popular culture, with starring roles in movies like “Contact,” starring Jodie Foster, the James Bond film “Goldeneye” and episodes of the “X-Files” television show.
But the future of Arecibo has become precarious. In 2007, the National Science Foundation, which has run the observatory since the early 1970s on an increasingly tight budget, said the observatory might have to close if a partner could not be found to take on some of the financial load.
In 2011, Cornell turned over management of the observatory to SRI International and two managing partners, Universities Space Research Association and Universidad Metropolitana de Puerto Rico, among other collaborators.
Since 2016, it has been managed by the University of Central Florida under a cooperative agreement with Universidad Ana G. Méndez and Yang Enterprises. The annual budget is about $12 million, including funds from NASA and the National Science Foundation, according to the University of Central Florida.
Still, the beat goes on. Only days after the accident, the University of Central Florida sent out a news release describing work by a team led by Jian Li, an astronomer at the Deutsches Elektronen-Synchrotron in Zeuthen, Germany, using the Arecibo telescope and other instruments. The team discovered what they called a “heartbeat” of gamma rays emanating from a gas cloud in the constellation Aquilla. The gamma rays — a very high-energy form of light — were being produced in rhythm with the outbursts from a wobbly and enigmatic black hole called SS 433, which is 100 light-years away from the cloud. It’s unclear how this black hole could cast its influence across so vast a distance.
“This result challenges obvious interpretations and is unexpected from previously published theoretical models,” Dr. Li said in a statement released by the University of Central Florida.
Interstellar hearts are still fluttering.