Ep. 459: Arecibo Observatory

The iconic Arecibo Radio Observatory has been a mainstay in science and science fiction. This Puerto Rico-based radio telescope was already in an uncertain level of funding. But now with the damage from Hurricane Maria, it might be shut down forever.

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Show Notes

Arecibo Observatory
Damage from Hurricane Maria in 2017
More Damage Reports
Arecibo Facebook page
Arecibo Observatory Twitter feed(English)
Observatory Facts
More Observatory Facts
Milestones of Arecibo Observatory


Transcription services provided by: GMR Transcription

Fraser Cain: Astronomy Cast Episode 459: Arecibo. Welcome to Astronomy Cast, our weekly facts-based journey through the cosmos. We’ll help you understand not only what we know, but how we know what we know. My name is Fraser Cain. I’m the publisher of Universe Today, and with me is Dr. Pamela Gay, the Director of Technology and Citizen Science at the Astronomical Society of the Pacific and the director of CosmoQuest. Hey, Pamela, how’s it going?

Dr. Pamela Gay: It’s going well. How’s it going with you, Fraser?

Fraser Cain: It’s going great. I had what had to be my greatest aurora experience of my life. I posted my video to the Twitters and the Instagrams. You say I should send it to APOD. I’ll send it to APOD. We’ll see if they take it. But unbelievable. My phone bleeped at me, told me there was a big geomagnetic storm overhead. I went out to this cool beach that we have that has a nice north view and saw the most insane aurora activity I have ever seen. It was ribbons. It was different colors. It was purples and yellows and greens. I really, really – I’m at a loss for words. So, check my Twitter feed. You should see the video.

But if you have never seen this, get like a phone or get a service – I know you use Twitter – and let yourself know that this is happening, and then go out and see if you can see an aurora.

Dr. Pamela Gay: It really is worth it. I’ve only seen an aurora like you saw last night once in my life, and it was the kind of thing where we all just stood there with our jaws open. And we hadn’t been expecting it. We just had a campfire up in the mountains in New Hampshire, and lo and behold, all behind the White Mountains, it’s one of these things you’ll never forget once you see it.

Fraser Cain: Yeah, that’s the real deal. Now, before we move on to the show, do you want to mention CosmoQuest’s new service that just came out?

Dr. Pamela Gay: I might want to.

Fraser Cain: Do it!

Dr. Pamela Gay: So, I want all of you – and I can see in the stats if you do this or not – I want all of you, when you listen to this podcast, to go to CostmoQuest.org/ImageDetective and help us explore our own planet. We’re currently at a time when, every time you turn on the TV, it’s like we’re seeing another “Here’s our planet wrecked” kind of photo. But the thing is, when you look at Earth from space, it looks glorious and awesome and beautiful.

And we have an entire Citizen Science project of photos taken by astronauts who do not label their photos, and if we want to be able to use these images for science to see when do you see the flowers blooming, you can actually see California bloom from the International Space Station. When are the rivers flooding? When do we see the first rains wetting down the farmers’ fields in that first corn bloom? When do we see our earth change? You can see all of this in Image Detective, and we need your help marking what is in every photo and figuring out what the heck the astronauts were looking at.

So far, I found Gibraltar. I found a shopping mall in Saudi Arabia. I’ve found a bunch of weird, cool stuff, so go online, CosmoQuest.org/ImageDetective. And like I said, I can see in the stats if you do this or not. Do not make me be a sad person. Please make my stats blow up. Thank you.

Fraser Cain: Okay, the iconic Arecibo Radio Observatory has been a mainstay in science and science fiction. This Puerto Rico-based radio telescope was already in an uncertain level of funding, but now with the damage from Hurricane Maria, it might be shut down forever.

So, two weeks ago, if we were gonna do an episode on the Arecibo, we would have talked about how it was financially in danger. And I’ll show some pictures to the folks watching this live, but wow! It could have been a lot worse, but, boy, it really took a big hit.

So, which do you wanna do? Do you wanna talk about Arecibo right now and just what happened, or do you wanna kinda go back through the history first? Let’s talk about what happened.

Dr. Pamela Gay: So, for the first time since before the Great Depression, a massive hurricane – by which I mean it was, at one point, a Category 5 – hit Puerto Rico with wind speeds of over 150 miles per hour, and the eyewall pretty much went across the center of the island, with the edge of that eyewall going straight over Arecibo Observatory. The island was completely devastated. There is no other way to put it. The entire power grid was knocked down. Freshwater system was mostly destroyed. The roads are such a mess that they’re basically not able to get in to people except with helicopters.

Now, the thing about the observatory is it’s high up. It’s well above sea level. It’s well above worrying about a local dam they think might fall down. It’s well above the flood stage for that. And from its safe place that has generators, that has food reserves, that has a helo pad, they are in a position to work on helping get the entirety of the island back online. So, they’re actually where FEMA is currently headquartered. But while they’re there helping to heal the whole island, it’s unclear what their own future might bring.

Fraser Cain: Yeah. So, let’s talk about what actual damage Arecibo suffered.

Dr. Pamela Gay: The city was pretty much destroyed. The city, there’s like a hospital in the process of falling into the ocean, which is not where hospitals belong. But the observatory itself, it was mostly unscathed. There was one very large radio line receiver that hangs down from that iconic centerpiece that is out over the, basically, crater of a telescope, and this nine-story-long feed line fell. It took out several – and I mean like order of ten – panels in this order of 10,000-panel radio dish. So, luckily, the one that fell, the one that was damaged, that 430 line, it isn’t used for a whole lot of the science, so most of the work the dish does, it can continue to do without that particular linefeed.

But not having power, you can only run on diesel for so long, and you can’t very readily use that dish as a radar, which takes a lot of power, when you’re relying on generators for everything.

Fraser Cain: So, right now, Arecibo is completely offline.

Dr. Pamela Gay: Yes.

Fraser Cain: It is not usable for any science, and really, until they get the instruments restored and the parts from the instrument cluster that fell down and broke, as well as the dish, as well as getting – they’ve got generators, but I don’t think they have enough power to actually run the instruments and stuff. So, really, there’s a ton of work that needs to be done to bring this.

And Arecibo was lucky compared to a lot of the places on Puerto Rico that were hit so much worse. Remember, you can even see Puerto Rico from space, and it is dark. There is no power, except for a few little corners of the island. So, it’s a bad, bad situation. Arecibo is, literally, now the least of people’s concerns, compared to the human crisis that’s going on, on this island right now.

Dr. Pamela Gay: And as we talk about the history, the skills, the amazing scientific impact that this observatory has had over way longer than you and I have been alive, I think that, in a certain way, the noblest thing it has done is provide that ground zero for FEMA, where NSF has basically said, “Here, FEMA, take our facility. Here is our helo pad. Here is our capabilities. We have a cafeteria. We have dorms,” and now it’s a place where, hopefully, the island can start rebuilding.

Fraser Cain: So, now, let’s go back and talk about Arecibo and sort of a history of the observatory. So, how long has it been around for?

Dr. Pamela Gay: This is amazing. It was constructed in the 1960s. This thing predates the two of us. It was really built as the first of the mega observatories, and up until last year, it remained the largest of the mega observatories, and it took China to defeat it.

Fraser Cain: Right, the FAST telescope.

Dr. Pamela Gay: Yeah. So, the origins of it go back to the 1950s, when folks were trying to figure out a lot of radar technology. So, this thing is based out of radar, versus receiver, technology. It was actually put together to be able to figure out warheads, figure out spacecraft, figure out all of these little metal objects flying through the atmosphere and above the atmosphere. It did not originally get its start as something for studying like distant neutron stars. That’s just kind of what it evolved to do.

So, it was completed in November of 1963. It was designed and run out of Cornell University for most of its history. And, yeah, it started out looking at small metal objects, went on to study the ionosphere, and then the more we learned about radio potential, the more it got used to do, well, stuff with cosmological implications.

Fraser Cain: Let’s talk about the scale of the thing. So, it is this gigantic radio dish, but it’s built in this really interesting natural formation, right?

Dr. Pamela Gay: Right. So, I didn’t use the word “crater” offhandedly. It’s essentially in a depression in the mountains that looks like a volcanic crater. It’s not a volcanic crater. It just looks like one. And where it’s carved into this mostly already existing depression in the hills, it’s 38,000 aluminum panels, each of which are several feet across. The entire thing adds up to 480,000 square meters, and all of these little aluminum panels are suspended on, basically, a hammock of big cables.

And so, build yourself a spherical hammock out of cables, plant shade-loving plants underneath it, and cover it all in an aluminum mesh, and because they’re working at these higher frequencies, longer wavelengths, they’re able to have this reflecting surface that reflects radio waves while also growing moss.

Fraser Cain: Right. Now, this is not a parabolic-shaped mirror, like a typical telescope dish and even like a lot of radio dishes. This is a spherical reflector, right? And so, how does this work differently than what maybe people are expecting?

Dr. Pamela Gay: Well, with a spherical reflector – I mean, there’s normal aberrations that you worry about in optical astronomy because what they’re looking at is a beam, and within the beam, do I see radio signal or do I not see radio signal. They’re less worried about the distortion that you get from a spherical mirror. And what they’re able to take advantage of with the spherical surface that you can’t take advantage of with a parabolic surface is, by moving around their focus point, they can essentially change what part of that sphere they’re using to look at the sky.

So, instead of trying to tilt, bank, move a 480,000-square-meter dish, what they’re moving is that little pointy bit at the top that’s on a bunch of cables. And by moving that around and changing what part of the reflected light gets captured by the feeds, they’re able to track things for a moderate amount of time as they scroll through zenith, essentially.

Fraser Cain: So, you can actually move this detector array that’s on these cables as the Earth is turning and be able to keep it fixated on some target, or, theoretically, if you’ve got an asteroid that’s moving on some angle, you can move it and be able to target. And there is no other way that you could target a dish this big. It’s just not possible. It’s just too big.

Dr. Pamela Gay: Exactly.

Fraser Cain: The scale of this thing compared to any other radio dish that’s out there is just –

Dr. Pamela Gay: Except the one in China.

Fraser Cain: Except for the one in China, which uses the same technique, right?

Dr. Pamela Gay: Mm-hmm, yeah.

Fraser Cain: So, what are some of the great discoveries that Arecibo has helped us out with?

Dr. Pamela Gay: So, it has been doing amazing things pretty much since Day 0. So, in April of 1964, it was used to figure out that Mercury, yet again, isn’t doing what we expect it to be doing. It’s like every time we’re able to look at Mercury in higher detail, one of those things that we had always thought was true turns out to be wrong. With Mercury, what they figured out was they had thought that the planet was tidally locked to Saturn, and it’s not. So, they were able to figure out that it didn’t have an 88-day period but instead had a 59-day period for its rotation day to night. So, that was kinda cool.

In ’68, it was able to figure out the speed at which the Crab Pulsar is doing its pulsar thing, which is 33 milliseconds.

One of the things that I think is particularly cool in light of the situation with Maria is it was used to find the binary pulsar, and I have to read its license plate number: PSR B1913+16. This was looked at in 1974, when we both were finally alive, by Hulse and Taylor, and this was the first binary pulsar that was observed and allowed us insights on gravity and spatial relativity that had never been seen before, and the two of them actually went on to get their Nobel Prize for this.

So, this was work that was done, and Joe Taylor is about as nice a guy as you’re going to get. Some of these Nobel laureates, you meet them in person, and they’re just like dorks with big toys that are having amazing results with their science. And Joe Taylor, he actually is a ham radio operator, and he was one of the first ones to get us information from the folks at Arecibo Observatory who also had a ham radio. So, here’s someone who did cutting-edge work with a giant radio dish, figured out binary pulsars and aspects of relativity, and then helped us find out that at least some of our team down there was safe, thanks to shortwave radio.

Fraser Cain: Right. I think we talked about this a bit in the Weekly Space Hangout this week – subtle plug for the Weekly Space Hangout. One of the things that’s really interesting about Arecibo is that, as you mentioned, it has this radar capability, and we did a whole episode of Astronomy Cast about radar astronomy, which is different from radio astronomy, but can you give people a bit of refresher on what Arecibo can do that makes it very special from pretty much any other large radio telescope out there?

Dr. Pamela Gay: So, it has the capability to both send and receive. The first observatory I ever worked at, Haystack Observatory in Massachusetts, is another one of the ones that do this. Pretty much if something is partially funded by the military, it probably has radar capabilities, and radar is when you send out a pulse of radio light and you measure the return time distribution. This is a burst that goes out. The packets that get back to you first came off of something that’s nearby. The packets that get to you second get to you off of something a little bit further away. And you can actually map out the distance to a bunch of different things by doing a sweep of your radio transmission and listening to the returns coming back off of that sweep.

With Arecibo, they have the ability to use radar to actively trace features on a surface to accurately measure the distance to objects. This was how we accurately finally figured out how big our solar system is is with radar astronomy. So, it gets used with Mercury to look for features on Mercury and measure how long it takes for those features to come back.

Fraser Cain: But even fairly recently, it has been analyzing asteroids that are doing nearby flybys of the Earth and being able to actually see features on the surface of these asteroids. It helped map asteroid Bennu. Of course, now, there’s a mission that’s on its way there. It’s found moons around asteroids. There are other radio telescopes, and there’s especially the Square Kilometer Array, and there’s a lot of really amazing observatories that are in development, but there just aren’t a lot out there that have this level of radar capability in addition to its radio observatory capabilities.

Dr. Pamela Gay: It’s not just asteroids anymore. It’s also comets. Back in February, Arecibo was able to observe Comet 45P/Honda-Mrkos-Pajdusakova. We’re gonna go with Comet 45P, which is what they say at the top of the press release. And with the observations they made, they were able to peer through the coma of the comet and start to resolve, “Well, the sucker’s rotating at 7.6 hours.” They were able to figure out the size more accurately as being 1.3 kilometers or 0.8 miles across.

And so, you can do things with radar that you just can’t do any other way because – well, in this case, the coma, that bright, reflective cloud of volatiles around the nucleus of the comet, you just can’t easily look through it.

And so, here, Arecibo is out there actively imaging asteroids that get near the earth, actively imaging comets that get near the earth, using radio light which it sends out, instead of using reflected sunlight like all the optical telescopes do.

Fraser Cain: And so, we’re gonna miss that capability. Let’s talk about some of the actions that Arecibo has been used to attempt to communicate with aliens.

Dr. Pamela Gay: I like the way you’re like, “What word do I use for this?” So, back in 1974 was the first example of Arecibo essentially sending out a message, and it was essentially the silliest little 8-bit mono-color graphic ever. I don’t even know how an alien would make sense of this thing. It doesn’t even fully make sense to me.

But anyways, Arecibo, in 1974, beamed out a 1,679-bit pattern to make a 23-by-73 pixel bitmap image that any life in the globular cluster Messier 13, which we now know doesn’t have any planets – had there been planets with life, or should there be life without planets, in M13, they will, at some point far, far, far in the future, like 25,000 years from now, they’ll be able to see this 23-by-73 pixel bitmap. And maybe, hey, there’s something between here and there that will receive it in the interim.

Fraser Cain: Well, how do you know that there’s no planets in Messier 13? It’s 25,000 light-years away. It has tens of thousands of stars in the cluster, each of which could have planets.

Dr. Pamela Gay: They have – and by “they,” I mean a number of different research teams – have looked for flickering of the stars consistent with transiting stars at such a level that, were there planets, it’s believed they probably would have found them by now, at least one or two. They did an in-depth study, I believe, of M15 using the Hubble Space Telescope. And these objects have such a low metallicity that this is actually consistent with our understanding of you have to have heavy elements in order to have planets to form out of the heavy elements.

Fraser Cain: Right. I still hold out hope. 25,000 light-years away, too far away, many stars in there, who knows? Who knows?

Dr. Pamela Gay: Okay, you can do this.

Fraser Cain: Yeah. And if we’re talking about maybe we could be finding life on Pluto in the radioactively heated subsurface areas, you don’t know. We don’t know.

Dr. Pamela Gay: You just need a surface.

Fraser Cain: Yeah, exactly. You need ice, and you need radioactive materials.

Now, of course, the problem is – and so, if we didn’t have what happened just with Hurricane Maria just in the last few weeks, Arecibo was already in a bit of a funding crisis. Can we talk a bit about that and where we got to?

Dr. Pamela Gay: Yeah. So, Cornell had been operating Arecibo for decades. I remember when I was an undergraduate, if you wanted to be a summer student at Arecibo; you actually were a summer student at Cornell who then flew to Arecibo.

And the issue became that the National Science Foundation, which had been operating Arecibo via Cornell as one of their major facilities, wanted to change the funding structure. So, in 2011, the National Science Foundation basically told Cornell, “We’re taking away your toys.” They said it slightly differently in a slightly nicer way, but that was the gist of it. “We’re taking away your toys. We’re going to transfer operations to a completely new facility, we’re going to be bringing on new management partners, and we’re going to ask everyone to try and find ways to fund this that don’t include the National Science Foundation any more than is absolutely needed.”

So, back in 2011, the Stanford Research Institute, SRI International, went on as the lead organizer. Along with that, it’s being managed by USRA, which is a standard organizing body. They run a lot of the major orbiting observatory contracts. They run a lot of contracts. USRA is the Universities Space Research Association, so it’s an association that runs these kinds of facilities. As well as the university – I think this translates to the Metropolitan University of Puerto Rico. The Spanish pronunciation is Universidad Metropolitana de Puerto Rico. Again, I speak Russian. I’m sorry.

And with this new funding source, this new way of looking at it, it has since then been consistently threatened to be shut down. We have heard numerous times while trying to figure out the budget for the next year, it’s been, “And we close Arecibo.” And everyone’s like, “No, no, no, no, no, no. No. No. No. No.”

And then, NSF comes out with “Dear Colleague” letters, and they’ve done this at least twice now with the “Dear Colleague” letters, saying, “We are looking for someone to run this who will cost less.” Again, they don’t phrase it exactly that way, but that’s what it boils down to. They’re looking for someone to run the facility in a competitive manner that will allow the National Science Foundation to spend less money for their science return.

Fraser Cain: Right. And when you think about all the NASA projects that are – they say they’re gonna shut down the Voyagers, they say they’re gonna shut down the Pioneers, and someone goes, “Oh, wait a second, we’ll cover it.” They say they’re gonna shut down the Mars Exploration Rovers, and they find the money. You can imagine them finding the money year after year after year, moving forward with Arecibo.

But now, it’s not just find the money to keep the thing operating and put off the maintenance of cleaning the moss off the detector until next year. It’s gonna take an investment to get it back online before you can even move to that maintenance phase. So, did Maria hit it with a death blow? Is it done?

Dr. Pamela Gay: We don’t know yet, and this comes down, in part, to being an ethical question, and it’s a complex, grey ethical question, as so many of them are, because, on one hand, Puerto Rico employs over 100 people. It provides this place with high-tech, high-skills jobs. The visitor center does education and public outreach. This is a facility that has a positive and wanted impact on its local economy, on the local education system, and it’s kind of this shining star. It’s also a historic site.

And at the same time, how do you justify the funds that are necessary to rebuild a facility that, yeah, it does good work, yes, it does unique work, no, there isn’t anywhere else out there that can do exactly the kind of imaging that it does. Manchester, up in the UK, does a fair amount of radar imaging as well, but Arecibo is the big boy out there doing it, and the women like Sondy Springmann that are out there operating it and getting these amazing scientific returns.

Yeah, that’s awesome, but there’s people without water. There’s so many other needs. How do you justify spending on something that does afterschool help and educational programs when there is no school? And I don’t know the answer, and I’m not sure anyone will know the answer until the roads are clear, and the roads still aren’t clear.

Fraser Cain: So, we’ll keep you posted. Thanks, Pamela.

Dr. Pamela Gay: Thank you.

Announcer: Thank you for listening to Astronomy Cast, a nonprofit resource provided by Astrosphere New Media Association, Fraser Cain, and Dr. Pamela Gay. You can find show notes and transcripts for every episode at AstronomyCast.com. You can email us at Info@AstronomyCast.com, tweet us @AstronomyCast, like us on Facebook, or circle us on Google+.

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One Response to Ep. 459: Arecibo Observatory

  1. Sarah November 19, 2017 at 1:24 am #

    Just wanted to let you know that on iTunes, the show notes for this episode have been accidentally duplicated from episode 458.

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