Iconic telescope falls after 57 years of feats
The Arecibo Observatory’s massive radio telescope collapsed thisweek in Puerto Rico, succumbing to an unceremonious and sudden death after 57 years of helping researchers study the Earth’s upper atmosphere, near space, and distant galaxies.
The plummet of a 900-ton platform onto the giant reflector dish 450 feet below was not, however, unexpected. The National Science Foundation, which owns the observatory, announced two weeks ago that the telescope would be disassembled. Its structure, with the instrument platform suspended above the reflector built into a sinkhole in the mountains, was in danger of catastrophic failure and could not be repaired without risking the lives of construction workers and the facility’s staff.
While officials were planning the safest way to disassemble
the telescope, the cables supporting the platform snapped Tuesday. The video released Thursday by the National Science Foundation shows the platform swinging and falling to the dish below. Nobody was injured.
“The engineers who evaluated the facility were clearly correct that it was dangerous,” said Bruce Betts, chief scientist at the Planetary Society. “I’m saddened personally and for science in general. It was a tremendous facility, and to see it ending its life in such a catastrophic way is a sad event for science.”
‘A personal tragedy’
The telescope was the brainchild of William E. “Bill” Gordon, who would later become a professor, dean, provost and vice president at Rice University. Gordon was interested in studying the ionosphere, part of the Earth’s upper atmosphere, and he designed and supervised construction of the telescope as a professor at Cornell University.
And after moving to Houston in 1966, Gordon used the telescope to study the ionosphere and Earth’s upper atmosphere. He trained 13 Rice Ph.D. students using the Arecibo Observatory. Gordon died in 2010at 92 — twoyears earlier he had celebrated his birthday at Arecibo — but his colleagues and former students have been emailing their telescope condolences to the university.
“The emails have just been flying in of everybody’s memories and how sad everybody is,” said Patricia Reiff, a Rice professor of physics and astronomy who worked with Gordon. “It was such a big part of their educational and research experience. It’s a personal tragedy.”
The nonscience community would recognize Arecibo through its appearance in movies including “Golden Eye,” released in 1995 as part of the James Bond series, and “Contact,” released in 1997.
It was also known for its effort to reach life on other planets. In1974, Cornell astronomy professors Carl Sagan and Frank Drake used Arecibo to send a radio message with basic information about humans into space — and to potential extraterrestrials.
“This was more of a symbolic event,” said Donald Campbell, a retired astronomy professor at Cornell and former director of the Arecibo Observatory. “Frank Drake thought it would be a nice gesture.”
The real benefit of the telescope was its massive size, which measured 1,000 feet in diameter and enhanced its sensitivity in studying objects near and far at radio wavelengths. Also unique was its ability to both receive radio waves fromspace and transmit radio waves into space, which is used to track and characterize asteroids, among other things. Goldstone Observatory in California is nowthe only place where radio waves can be transmitted from Earth into space for research.
Electromagnetic energy travels in waves that span a continuum from very long radio waves to very short gamma rays. The human eye can see only a small section of this spectrum, visible light, whereas other machines such as radios and X-rays use other portions of the spectrum.
“There’s a lot of objects in the sky that primarily emit in radio,” Reiff said. “And the bigger the telescope, themore of them we can see.”
Instruments on the platform suspended above the reflector dish allowed Arecibo to be pointed at a specific target in the upper atmosphere, near space or deep space. Then radio emissions from that target bounced off the curved dish and to the platform that recorded the data.
When it sent radio signals into space, the platform created a signal that was bounced off the dish into space.
Over the decades, Arecibo has contributed tomany scientific discoveries. It was used to find the first planet outside our solar system, to better understand Earth’s ionosphere and to indirectly confirm Albert Einstein’s theory of general relativity. The latter was achieved by observing the remnants of two supernovas (which are explosions of massive stars at the end of their lives) orbiting each other as they pulsed in radio waves.
But the telescope’s initial funding came from military sources. The Department of Defense was interested in detecting incoming missiles as they traveled through the ionosphere. It was thought Gordon’s design might be able to detect waves created in the upper atmosphere and ionosphere, Campbell said.
“I don’t think that it was terribly useful from (the Advanced Research Projects Agency’s) point of view,” Campbell said, “but it was very nice that they funded it.”
Due to DOD funding, the telescope had to be in a U.S. territory. Puerto Rico was near the equator, which allowed the telescope to also study the sun and nearby planets, and its large limestone sinkholes provided a natural geometry for the dish.
The telescope was completed in 1963, and the observatory has been stewarded by the National Science Foundation since the 1970s.
Chance of rebuilding?
There have been financial and environmental struggles in the past decade. But Ralph Gaume, director of the NSF’s Division of Astronomical Sciences, said funding was not the reason Arecibo collapsed. After one of the support cables became detached in August, the NSF immediately authorized the use of funds for engineering analysis, forensics evaluation and repairs.
Engineers were preparing to stabilize the structure when a main cable broke on the same tower on Nov. 6, prompting them to conclude that the remaining cables were weaker than originally projected.
During a news conference on Thursday, Gaume said itwas too early to say if the radio telescope would be rebuilt. The NSF has a process for building major research equipment and facilities that includes working with Congress and the scientific community.
But he did emphasize that the entire observatory is not being shuttered. Its roughly 40-foot telescope used for radio astronomy, aswell as its other facilities, will be reopened as soon as possible.
“We recognize the significance of this loss to Puerto Rico and the significance of this loss to so many who have called the Arecibo Observatory home, whether it be for years or a week,” Ashley Zauderer, NSF program manager for the Arecibo Observatory, said during the news conference. “Like many scientists, I spent time there as a graduate student. The telescope was special, suspended in a way that made it seem to float and defy gravity.”