Arecibo Observatory, Puerto Rico

This is a sad day for science. We will never see the likes of Arecibo again and I literally have colleagues crying right now, not just because of the science lost but because Arecibo was so close to many lives. (Many got their first start in the field at Arecibo through its student programs, I know at least one couple that met there, and it was iconic in Puerto Rican identity.)

What happened?

There was a cable break in August, followed by a main cable break holding the gigantic 900 ton feed horn (that James Bond ran on- or rather his stunt double, astronomers bragged Pierce Brosnan was too scared to do what they do every day), and it looks like the entire thing finally collapsed onto the dish below. It was the size of the house and where all the expensive equipment was.

Can they fix it?

No. This is the equivalent on an optical telescope of the bottom where your eyepiece/camera falling out and smashing a hole in the mirror. It’s gone.

Did they save any of the millions of dollars of equipment?

Again, no. It was far too dangerous to get into the horn once the main cable snapped and engineering reports indicate they were keeping people very far from it. For good reason based on this development…

What happens now?

The NSF is under contract to return the telescope site to its original natural state so I guess the demolition will begin. There is not money or interest in rebuilding this magnificent engineering marvel.


To answer some questions you might have:


It’s a 50 year old telescope- was it still doing good science?

Short answer: yes. Arecibo has had a storied history doing a lot of great radio astronomy- while its SETI days are behind it (it hasn’t really done SETI in years) the telescope has done a ton of amazing science over the years- in fact, Arecibo gave us one Nobel Prize for the discovery of the first binary pulsar (which was the first indirect discovery of gravitational waves!). More recently, Arecibo was the first radio telescope on the planet to discover a repeating Fast Radio Burst (FRB)– the newest class of weird radio signal- which was a giant milestone in our quest to understand what they are (we now think they are probably from a souped up type of pulsar, called a magnetar, thanks in large part to the work Arecibo has done). Finally, Arecibo was also a huge partner in nanoGRAV– an amazing group aiming to detect gravitational waves via measuring pulsars really carefully- so that’s a huge setback there.

Can’t other radio telescopes just pick up the slack?

Yes and no. FAST in China is an amazing dish that’s even bigger than Arecibo, so that’ll be great, but right now is still pretty limited in the kind of science it can do. Second, it doesn’t really have the capability to transmit and receive like Arecibo does- Arecibo was basically the biggest interplanetary radar out there, and FAST has said they might do that but it’s not currently clear the timeline on that- Arecibo would do this to update the shape and orbits of asteroids that might hit Earth someday using radar, for example, so we just don’t have that capability anymore.

Beyond that, you could of course do some science Arecibo has been traditionally doing on telescopes like the Very Large Array (VLA) or the Very Long Baseline Array (VLBI), but those are oversubscribed- there are literally only so many hours in a day, and right now the VLA for example will receive proposals for 2-3x as much telescope time as they can give. Losing Arecibo means getting telescope time is now going to be that much more competitive.

Why don’t we just build a bigger telescope? One on the far side of the moon sounds great!

I agree! But good Lord, Arecibo has been struggling for years because the NSF couldn’t scratch together a few million dollars to keep it running, which probably led to the literal dish falling apart. Do you really think a nation that can’t find money to perform basic maintenance is going to cough up to build a radio telescope on the far side of the moon anytime soon?! Radio astronomy funding has been disastrous in recent years, with our flagship observatories literally falling apart, and the best future instruments are now being constructed abroad (FAST in China, SKA in South Africa/Australia). Chalk this up as a symbol for American investment in science as a whole, really…

So yeah, there we have it- it’s a sad day for me. I actually was lucky enough to visit Arecibo just over a year ago (on my honeymoon!), and I’m really happy now that I had the chance to see the telescope in person that’s inspired so much. And I’m also really sad right now because science aside, a lot of people are now going to lose their jobs, and I know how important Arecibo was to Puerto Rico, both in terms of education/science but as a cultural icon.

This is a sad day for American science. We will definitely know a little less about the universe for no longer having the Arecibo Observatory in it.