IRA FLATOW: This is Science Friday, I’m Ira Flatow.

If you’re a fan of the movie Contact, you have, in some sense, visited the Arecibo Observatory. Near the city of Arecibo, Puerto Rico, it sits in a giant sinkhole in the island’s mountains. More than 50 years old, the telescope has been a tool for astronomers who’ve made historic discoveries there. And it’s been invaluable in the hunt for Earth-killing asteroids.

But now, the telescope is in danger of total collapse. Two key cables have broken, putting escalating strain on the structures that remain. And just yesterday, the National Science Foundation announced that the instrument would, in fact, be decommissioned, possibly even dismantled. Sci-fi Producer Christie Taylor took a look at the telescope’s scientific value, cultural importance, and what we know so far about the end of the line for Arecibo.

CHRISTIE TAYLOR: The Arecibo Observatory was until very recently the world’s largest single aperture radio telescope and at nearly 60 years old, Arecibo was still collecting radio data and radar at levels of detail that no other instrument can match. It’s iconic, it’s long-storied, its weathered time and hurricanes, like Maria in 2017, and, increasingly, earthquakes. All of this possibly leading to its downfall. And, after yesterday’s NSF announcement, it is apparently done as a scientific observatory.

Here to explain the decision to decommission is Nadia Drake, a contributing reporter for National Geographic who has been following the story about the telescope. I should also note that she has personal ties to our CEO. Her father, astronomer Frank Drake, was the observatory director years ago, and her partner currently conducts research using data from the telescope. Nadia, first of all, how bad is the damage that’s led to this really final-seeming decision?

NADIA DRAKE: So the situation at Arecibo is dire. It’s dangerous. If you look at the telescope, you see that there’s this enormous dish, and there is a suspended platform above it. And that platform is held up by cables running to it from three different towers.

And so what happened in August was that one of the auxiliary cables coming from what they call tower four slipped out of its socket. It fell onto the dish, and it damaged the dish. It took out some of the panels. And then, on November 6th, a primary cable coming from that same tower snapped. And that left that particular tower in a really bad situation.

So instead of having six cables, now there are four that connect that tower to the platform. And folks are really worried that if one more of those cable snaps, there’s a really good chance that the platform is going to go crashing into the dish. And that would be the end of the telescope for sure.

And what’s been happening is that engineering firms on site are looking at the telescope. They’re evaluating it. And they’re seeing that some of those cables that remain are showing signs of damage and degradation. And so nobody really wants to make any bets on how long it’s going to be before another cable snaps. It seems kind of like an inevitability, which makes the whole situation extremely dangerous.

CHRISTIE TAYLOR: What, then, does it mean that the National Science Foundation will be decommissioning this observatory?

NADIA DRAKE: So NSF has decided to decommission the telescope with the Arecibo Observatory, which means that they’re going to shut it down. It’s not going to be operational anymore. The agency said it’s just not safe to have people up there working on the telescope or trying to repair it. So the best thing to do now is to just shut it all down.

We have information from three engineering firms that were on site to evaluate the current situation. And one of the firms said that there is basically absolutely no way to save the telescope safely. They were predicting that in the absence of any work whatsoever, it will fall down on its own in the near future.

And said that it was just an unsafe situation. So that firm is actually recommending what they’re calling a controlled demolition of the instrument. So essentially, I guess, blowing it up in a controlled manner. Not actually sure what that means or what that would look like.

A second firm had proposed some options for stabilizing the structure. And one of those is, essentially, tipping the towers inward a little bit, removing tension from the lines. The third firm said, yeah, there’s really no way to do this safely. And so NSF, I think, looked at all of that information and decided that they were going to decommission it.

CHRISTIE TAYLOR: Do you think that they made the right choice or not?

NADIA DRAKE: Yeah. I think they made the conservative choice. I think they’re certainly choosing to prioritize safety, which makes sense. We don’t want anybody to die trying to save a telescope. That seems like a tricky calculus to make.

I do wish, as a lot of people do, that they had tried to stabilize the structure. This telescope is so recognizable. Someone called it a monument to human curiosity. The role that it plays, not just in movies, but in people’s lives, is profound. And so I think that’s why this is a surprise for a lot of people.

But the fact is it’s old. A lot of these cables have been there since it was built. Replacing all of them is going to be really expensive. It’s going to take a while, and as the structure continues to age, and potentially degrade, there’s just more and more things piling up that are going to be needing money for repairs.

Right now, my thoughts are really with the people of Puerto Rico, for whom this telescope is so symbolic. It’s such an inspiration and a source of pride. And so I’m just really feeling the loss for the island. And I’m thinking about the observatory staff, and what they’re going to do next.

CHRISTIE TAYLOR: That’s Nadia Drake, contributing writer for National Geographic. The day before the NSF announcement, I talked to Nadia and an astronomer, former observatory director, Dr. Mike Nolan, about why this telescope’s loss is such a big deal, both for science and for the people of Puerto Rico. And I started with asking Nadia about what the research world will is.

NADIA DRAKE: So in addition to being a radio telescope that actually collects radio waves from the cosmos, Arecibo also has the world’s most powerful planetary radar. And basically, what that means is that it can zap asteroids in the solar system. And by doing that, it can characterize those asteroids, and tell us a little bit more about what types of object might be on Earth-crossing orbits.

And so that’s really important if you’re considering how to deflect an asteroid that might be on an Earth-crossing orbit in the future. You want to know how big that thing is. You want to know what its composition is. You want to know what its surface looks like, and then come up with a mitigation strategy. And what Arecibo does is it allows us to do that kind of mitigation planning. And it also gives us a very, very, very precise orbit for asteroids.

CHRISTIE TAYLOR: When we talk about planetary defense it can feel maybe a little bit like science fiction sometimes. But Mike, how seriously do scientists take this possibility of an asteroid threat?

MIKE NOLAN: It’s sort of an interesting natural disaster kind of question, in the sense that the odds are low. It has definitely happened before that an asteroid has done horrendous damage to the– well, the planet survives but the creatures on it. And so the odds are the odds of something doing signally damage are small.

But unlike earthquakes or volcanoes, it’s something we could specifically do something about. If we did say this asteroid has a 50% chance of hitting, we would have ways to deal with that problem and eliminate that risk. Right now, the two most likely objects to hit will hit in order of 100 years, and have like a one in 1,000-ish probability of hitting. And those are the asteroid Bennu, which the OSIRIS-REx mission is just returning from. And that’s when I’m working on now. And the other one is the asteroid Apophis.

And both of those have, of order, one in 1,000 chance of hitting. And by making these very precise measurements, we can say, oh, yes it will, or yes, it won’t, or no, it won’t. And then we could do something about it. And so that’s how it’s different from other kinds of more likely events is that there’s concrete ways we can address the problem and solve them.

CHRISTIE TAYLOR: Yeah, speaking of other kinds of observing, too, I talked to Dr. Ed Rivera Valentine, who is a scientist at the Lunar and Planetary Institute. They worked at the observatory until very recently. They were going to use the telescope in September to examine the surface of Mars at its closest approach to Earth, which is this really rare opportunity that won’t repeat until 2067.

ED RIVERA VALENTINE: So previous work with Arecibo and Mars was able to identify these ancient volcanic provinces on Mars. And it was actually able to show these flow features connecting them, connecting these different terrains, which we did not see with the spacecraft we had orbiting Mars. If Odyssey will remain, and it’s operational, in 2023, I can see Mars, but it’s going to be– the level data I’m going to get is about, if you think about it in terms of signal strength, it’s going to be a quarter the signal I would have gotten this year. So that really weakens our ability to help out.

CHRISTIE TAYLOR: Nadia, Mike, what other kinds of observing opportunities could we be losing out on if this observatory stays down?

MIKE NOLAN: So I study asteroids, and most of my work at Arecibo was dating asteroids. And so you observe them when they come close to the Earth. When you’re using radar, basically, you’re using your own flashlight to illuminate an object. And then you take a picture of it. But because the light has to travel both out and back, it has to be pretty close to you to do that.

So every few months, an asteroid will come by, that could present a hazard that we can’t measure, or, actually, could present an opportunity, for example, to plan a space mission. The OSIRIS-REx mission used very heavily the radar observations that we did in 1999 and 2005 to plan that mission. So a billion-dollar space mission was planned using these Arecibo radar data. And that’s the sort of thing you won’t get. We were expecting to do a couple of different objects over the next six months that clearly are no longer in the cards.

NADIA DRAKE: Yeah, one of the projects that comes to mind is actually the one that my partner works on, which is looking for gravitational waves that are produced by colliding supermassive black holes. And Arecibo is one of the two telescopes that they use primarily. And what they’re doing is they’re looking at pulsars. And Arecibo is a fantastic instrument for pulsar observations.

They’re very dense neutron stars that spin very, very quickly, and they emit radio waves that, essentially, look like a lighthouse when they wash over Earth. They’re periodic, you can time them. And if you have enough pulsars, you can look for deviations in timing that indicate that gravitational waves are passing through, and stretching, and contracting space-time. They think they’re getting actually pretty close to a detection, it’ll just take longer for them to get there.

CHRISTIE TAYLOR: Yeah, and back to Dr. Rivera Valentine, who is, by the way, Puerto Rican. They also had a lot to say about the value of the telescope has to the people of Puerto Rico. It’s comparable in its sheer iconicness and value to, say, how a New Yorker might feel about what would happen if the Statue of Liberty was broken or had disappeared.

ED RIVERA VALENTINE: I’m pretty sure a New Yorker would be incredibly hurt. They would take that personally, because the Statue of Liberty is viewed nationwide as a symbol of New York City. So for us, in Puerto Rico, the Arecibo Observatory is the same thing. But from a cultural perspective, it goes beyond that, because it is a symbol of our ability to go beyond our limits. It’s the symbol of look, we can do science, too. We can be involved in this.

It’s that motivational symbol. In Spanish, we say it’s the [SPEAKING SPANISH]. It’s that reached icon. People in PR, when you tell them you work in the observatory, they’re like, what, they’re super happy for you. Oh, you work at the observatory? You must be amazing. OK, let’s help you out.

CHRISTIE TAYLOR: Just a reminder that this is Science Friday from WNYC Studios, I’m Christie Taylor. Dr. Rivera Valentine also grew up in the city of Arecibo, right by the telescope. And they credit the observatory, which also offers these summer science programs to local youth, as the big inspiration for them entering the field of astronomy.

ED RIVERA VALENTINE: You have to understand that when you come from a majority impoverished culture– when people come from that background, and they think of progress, and they think of science, they think the medical scientists, because your day-to-day interaction with science is really that medical professional. So having the observatory there, as a person who is incredibly squeamish to blood, and did not want to do anything with medical sciences, having the observatory there was an example of no, there’s other things in science that you can do.

I got the opportunity to manage a program there for high school students. And to work with them and get to do research at the observatory with us. And I got to see that they, too, were as inspired as I was when I was a kid. That whole inspiration, looking out at the dish, and going, wow, one day I can do this. I got to see that in them. And that, that itself is amazing.

CHRISTIE TAYLOR: Nadia, when we talk about this telescope having a personal connection for you. What does it feel like to be reporting on its potential collapse?

NADIA DRAKE: It’s scary. When I first heard that the second cable had come down, I started imagining what it would look like if that platform were to crash to the ground. It’s 500 feet up. And so just the images in my mind are kind of terrifying.

What is that going to look like if it comes down? I hope nobody’s up there or around it, because it’s a very precarious situation. It’s the kind of recording that nobody ever wants to do. You never want to be reporting the bad news stories. And I just feel like Arecibo deserves a better end than this. If it comes to that.

CHRISTIE TAYLOR: Mike, you were there for 20 years. How about you?

MIKE NOLAN: Yeah. It’s just hard to really imagine, because what we always did was, when faced with a problem, which we’ve been having– I mean, there’s always problems with something like that, we’ve always had funding problems. The solution has always been buckle up and fix it. Just we’ll get through this. And this is the first time when I’ve been not quite sure that we’re going to.

And it’s difficult to know what to do. As Nadia said, imagining it after it falls is just– I can do it intellectually, but I don’t know where we would go.

CHRISTIE TAYLOR: I’m back with Nadia Drake. And Nadia, we’ve talked about the NSF’s decision to decommission the observatory. But what actually happens next? I know I saw a NASA administrator tweet, for example, that the visitor’s center would remain open, that they might still run school programs. But what actually might happen?

NADIA DRAKE: I don’t know what kind of timeline they’re looking at. I would find it incredibly improbable that the telescope would remain upright for a while, just given how precarious the situation is now. One of the firms that was on site had also mentioned that, in their estimation, it’s just a matter of time before it comes down on its own.

So if you’re considering that, it’s probably better to dismantle it as safely as possible so that places like the visitor center can remain intact. And can be places for people to come visit. Definitely one of the ideas that they’re considering is keeping the site and using it for educational purposes. It’s tough for me to imagine how that would work without an actual telescope there.

CHRISTIE TAYLOR: Nadia Drake is a contributing writer for National Geographic. She’s been covering the Arecibo Observatory this week. For Science Friday, I’m Christie Taylor.

IRA FLATOW: And to everyone in the science community mourning this announcement, especially Puerto Rican scientists, we are all very sorry for your loss.