The Arecibo Observatory has fallen. This marks the end of a nearly 60 year sky gazing career that has not only helped us to better understand the universe, but has also scoured the skies searching for any signal from extraterrestrial worlds. So, what happened to this one of a kind behemoth structure?
What we know right now is that the destruction of this iconic observatory was due to multiple cable malfunctions. The National Science Foundation hasn’t given any further details about the fall, but we do know that at the beginning of November 2020 they'd actually been discussing plans to safely decommission the observatory by gently lowering the central platform. But unfortunately, nature had other plans. Luckily, no one was harmed in the collapse of the observatory, but sadly this ends an era of space exploration. The initial idea for Arecibo actually started in the 1950s by Professor William Gordon from Cornell University. Gordon had the desire to study the ionosphere, which is the layer of our Earth’s atmosphere that can reflect radio waves.
The funding for this revolutionary project came from the Defense Advanced Research Projects Agency or DARPA in 1959, when Cornell University signed a contract to conduct development studies centered around large-scale radar probes.
Four years later in 1963, construction was completed in the limestone hills of Arecibo, Puerto Rico. The completed project featured a 817-metric-ton equipment platform, which was suspended over 152 meters above its spherical reflector. This reflector measured 305 meters, making it the world’s largest single radio telescope of its time.
Well, until 2016 when China developed its own single radio telescope called the Five-Hundred-meter Aperture Spherical Radio Telescope, or FAST. And as the name implies it is nearly 200 meters larger than Arecibo. But did FAST send one of the first radio messages ever into deep space?
Known as the Arecibo Message, it 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. It was then broadcasted into deep space toward the M13 star cluster in the Hercules constellation.
The famous 1,679-bit picture was intended to demonstrate the tremendous broadcasting capability of Arecibo while also potentially contacting any extraterrestrial life living within the M13 star cluster. Pretty freaky, huh?
And to make things even cooler, in 1992 Arecibo changed our understanding of space forever when scientists used it to discover the first exoplanets, or planets outside of our solar system. This discovery came more than 2,300 light-years away, orbiting a pulsar named PSR B1257+12. And if you’re wondering what a pulsar is, it’s a neutron star, which is actually one of the densest known objects in the universe. But unlike regular neutron stars, pulsars give off regular pulses of radio frequency. Which could be picked up by the highly sensitive antennas on Arecibo. Discovery of exoplanets gave scientists around the world confirmation that there were other orbiting bodies outside of our own solar system.
Since its initial construction, Arecibo got a major upgrade to make it even more impressive. In 1996, the Gregorian dome was added to the observatory. This allowed it the unique ability to transmit radio waves and receive their reflections from other objects. This was done using a series of mirrors, to focus radio waves both in and out of the dome.
Scientists could then set the receivers to monitor asteroids. And when it comes to planetary defense, ignorance is definitely not bliss. To date, NASA has identified nearly 25,000 near earth objects, thanks to the help of Arecibo and other instruments.
The loss of Arecibo is huge in the astronomy community, even sparking the social media campaign #WhatAreciboMeansToMe. But now the astronomy community is moving forward by trying to replicate some of Arecibo’s functionality in other instruments.
As for me, I’m personally looking forward to using the technologies we have today to continue our exploration of the galaxy through radio frequency. And who knows? Maybe we'll develop an even better version of Arecibo in the future. Did you know that Arecibo was built into a natural sinkhole?