Planetary Radio: Space Exploration, Astronomy and Science - The Search for Extraterrestrial Polluters?

Episode Date: August 12, 2014

Harvard’s Henry Lin led work that determined the soon-to-be-launched James Webb Space Telescope may be able to detect an alien civilization by analyzing its atmosphere.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

The search for extraterrestrial polluters, this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society, and I think you're going to enjoy this one. Henry Lin is going to tell us about his team's work on finding advanced aliens, not from their radio signals, but the CFCs in their atmospheres. Bill Nye looks at the real benefits of an asteroid retrieval mission, and Bruce Betts will be along with news of a pretty amazing conjunction in the night sky. It's always nice to

begin with Senior Editor Emily Lakdawalla. Emily, I want to get to New Horizons in a moment, but first of all, I mean, it was just last week that we talked about Rosetta nearing the comet, and now it's there. Yeah, and it's certainly very cool looking. You know, it's a very strange looking object. It's clearly two separate objects that are joined together, although I think it's an open question whether it's clearly two separate objects that are joined together. Although I think

it's an open question whether it's two originally separate objects that joined together, or two objects that are going to become separate in the future that originally started out as one. I don't think we know that yet. And it's I'm looking forward to Rosetta trying to figure that out. And it's an interesting mix of the familiar and the strange. If you look at a picture of all six comets that we visited up close and taken pictures of, this now makes it four out of six that appear to have this kind of double lobed shape. So it's actually a fairly common shape. And some of the features on the surface really remind me of like the circular features we saw on Comet Tempel 1, also of the depression type features that we saw on Comet Vilt 2. So it's really exciting to begin to see enough objects that we can sort of divide things

into classes and say, well, this comet has this thing and this other comet has these different things and try to understand what makes all of those different kinds of features appear on different comets. It's going to be a very exciting mission for that reason. It's in an August 6th blog entry by Emily at planetary.org. You want to see these images. They are really beautiful, especially a breathtaking one in 3D. So get out those red-blue glasses, folks. Let's move on to something you did

the next day, I believe, about what looks from a distance like a binary star system. It really does. And it is a binary system, but it's not a star and it's not a planet, according to the IAU. It's Pluto and it's moon Charon. The thing that I love most about this initial optical navigation series of images that New Horizons took of Pluto and Charon is the fact that you can actually see the pair of them pulling each other in circular motion when you compare them to the background of stars. Charon is a large enough fraction of the size of Pluto that both objects are orbiting around a point that is actually outside of Pluto entirely called the barycenter of the system. You know, when I look at the two objects moving around each other like that, clearly having such

a great influence on each other, it makes it very hard for me to call it something because both of those objects are clearly equally gravitationally important in their system. Like I call them worlds. It could be a binary planet, could be a binary dwarf planet. I don't know what it is, but whatever Pluto is, Charon is the same thing. It's the same kind of thing around world influencing the motion of its neighbor. And just seeing the two of them orbiting around each other like that, it's so strange and so different from anything that we've seen anywhere else in the solar system that it's just made me even more excited to see them up close when New Horizons passes by about a year from now. So we are just getting underway. Stay tuned, everybody. And we

will be talking with Emily once again next week. Thanks, Emily. Thank you, Matt. She is our senior editor and planetary evangelist, also a contributing editor to Sky and Telescope magazine. Up next is the CEO of the Planetary Society, Bill Nye. Bill, we have talked about it before, but the asteroid retrieval mission, ARM, is once again in the news, specifically in space news. Yes, yes. So the idea is to send a rocket with people on it out to rendezvous with an asteroid beyond the orbit of the moon, and the with an asteroid beyond the orbit of the moon. And the asteroid would get beyond the orbit of the moon because we drag it there with another spacecraft. It sounds exciting, but this asteroid would be pretty small. And a couple of the candidate

asteroids, ones that would work for it, are going to be explored with other spacecraft. It's not clear you want to do that twice. But the big thing is the scientific community is not supportive of it because if you were going to design a mission to do science, this isn't what you'd do. Too much going on, too expensive, too many things. Many people view it as a make work project for certain aspects of the human spaceflight program, but maybe that's not a bad thing. Maybe that's the best thing for all of humankind is to get humans out there and just give people a new place to shoot for. And that will excite lawmakers to fund something new and cool to a really distant destination, a really distant asteroid and make discoveries about where we all came from and the

origin of the solar system. But it's a hard thing. I mean, these things are very expensive. Should you be doing this mission or some other mission that is more organized for a specific purpose rather than using hardware that's so-called destination agnostic, not concerned with where it's actually going when it's being designed. It's just going to go somewhere. We're going to make something that goes somewhere, like building a car without picking a city to drive to. If nothing else, it's nice that there is at least some discussion of going somewhere other than low Earth orbit.

That's right. You want to go out beyond the orbit of the moon. That would be really good. to the moon. That would be really good. The trouble is that, or a feature is that Orion space capsule, which would be the thing you'd use, can only go about 20 days, 22 days in space. And people have flown for a lot longer than that on smaller capsules and of course on the International Space Station. So how much innovation will really take place? It's a tough question. So the discussion will continue, Bill, and I expect you and I will be talking about it again as well.

Yes, I hope so. And notice, please, that the Planetary Society is featured prominently in this month's Popular Science. Well, and even more prominently, The Science Guy. It's a very nice piece, and there he is right on the cover. It came in my mail today. It's the

September issue of Popular Science. And if you want a nice behind the scenes visit with Bill Nye, the CEO of the Planetary Society. There it is. Thank you, Bill. Thank you, Matt. So now we talk about a new way to look for extraterrestrial intelligence by looking for their pollution. The paper in the Astrophysical Journal Letters is called Detecting Industrial Pollution in the Atmospheres of Earth-Like Exoplanets. And it's not as crazy a goal as you might first think. I got hooked as soon as I saw the press release.

Harvard's Henry Lin is the lead author, working out of the Harvard-Smithsonian Center for Astrophysics. This young researcher, I won't tell you how young just yet, spends most of his time studying clusters of galaxies. When we talked via Skype recently, he shared his excitement about this very different line of fascinating research, a new take on SETI. Most of the techniques that we use now to search for intelligent life focus on receiving electromagnetic radiation from the alien civilization, whether that be by searching for deliberate emissions that they send to us, or maybe just the bright lights on their planet,

or perhaps the messages that they send accidentally and they leak out into space. We looked at a completely new method, which is similar to how we search for so-called unintelligent life on distant planets, which is by measuring the atmospheres of their planets to great precision. There's already a technique where we search for gases like molecular oxygen in combination with, say, methane, which would be a sign that plants exist on this alien planet and photosynthesize. Here we are searching for industrial pollutants, which could be found on alien planets.

And if they were found, we would be fairly confident that this would be the sign of technology and industrial processes, because these particular industrial pollutants that we focused on are not produced naturally or are produced naturally in only very, very limited quantities. We are searching in a slightly different region of the spectra. Molecular oxygen is at shorter wavelengths than the pollutants that we targeted. But it's essentially the same concept. We just wait for the exoplanet to go between the host star and the telescope, and then we can take a very quick spectra of the planet. And because a small amount of the starlight passes through the atmosphere of the planet, any signatures inside the atmosphere will leave a fingerprint on the spectra, and that's what we're searching for. Now, I want to come back to those pollutants, but you based this work on a telescope

that we talk about quite often on this program that isn't up there yet. How were you able to do that? And tell us what telescope it is. So it's the James Webb Space Telescope. It's essentially the replacement of the Hubble Space Telescope. And it's going to be much more powerful. The advantage of a space telescope over a ground-based telescope in our case is that, you know, the atmosphere is warm. It emits lots of radiation. It also, the particular molecules that we're searching for are the molecules that are found in our own atmosphere. It would be very difficult to distinguish between whether or not the signature that we're measuring, if we use a ground-based telescope,

is something in our atmosphere or if it's something coming from the alien planet. So that's why we focused on the James Webb Space Telescope. Now, the James Webb will be launched in a few years if everything goes according to plan. We already know, because many of the parts have been constructed already or are being constructed, what its capabilities will be. So we can simulate its capabilities when looking at these distant

exoplanets. I like this phrase that you've come up with, synthetic spectra. Yes, we computer simulate the spectra based on the spectra that we observe on Earth. We can play with some of the parameters like the concentration of these the parameters, like the concentration of these CFCs or the concentration of other molecules in the air and see how that affects how long we need to expose and other challenges that come up if there are high concentrations of other things that interfere with what we're looking for. Will this work with just about any exoplanet and any sort of star, or are there other constraints? There are a few caveats. In this paper, we focus on exoplanets,

which are Earth-sized, and that they are orbiting a very special object called a white dwarf. A white dwarf is a sun, like our sun, except that it has already died. It has the same mass of the sun, approximately, but it's only the size of the Earth. This gives us a great advantage when we're trying to measure the atmospheres of these sun approximately, but it's only the size of the earth. This gives us a great advantage

when we're trying to measure the atmospheres of these distant planets, because if you imagine a huge star, when the planet goes around that huge star, it only blocks out a very, very small amount of the starlight, and only a very small fraction of the starlight gets filtered by the atmosphere. On the other hand, for a white dwarf, it's about the same size as the planet that we are trying to find. So as a planet goes around the white dwarf, it blocks out almost all of the sunlight, or at least maybe a fraction, like half of the starlight. And so a very large fraction compared to the normal case of a planet going around a large star will get filtered by the planet's atmosphere. So basically, it's a game. I mean, by using a smaller source to cut down

on the background noise, and we can measure these very, very precise, very, very subtle signatures with future technology. Otherwise, if we want to search for pollution on planets orbiting main sequence stars like our sun, we'll have to wait even longer. We'll have to wait for even more advanced technology. Something beyond the JWST. Something beyond the JWST. Hasn't there been research recently that indicates that maybe white dwarfs aren't such a bad place to look anyway? that are very close into the sun will get engulfed by the sun and presumably be destroyed. And then how are you supposed to have life again once your inner planets have been destroyed? In particular, for a white dwarf, it's small, so the planets have to be close in if they want to be hot enough in order to sustain liquid water.

Well, in 2011, there was a paper in Nature where they reported observations of two rocky planets around a star which had undergone a similar fate, where it had expanded and then what was left was a white dwarf progenitor. In this paper, they showed that, yes, it is possible that planets can exist very close in, right in the habitable zone, essentially, of a white dwarf. Now, this wasn't exactly the same system as a white dwarf, but it's very, very close. So it suggests that if this is true, there's no reason to believe that it can't also happen for a white dwarf, but it's very, very close. So it suggests that if this is true, there's no reason to believe that it can't also happen for a white dwarf. And the planets can get there by a variety of mechanisms. One, they could form by the debris generated by the dying

star, just in the way that planets normally form. A second possibility is they could have started farther out where they wouldn't have been affected by the dying star, and then they could migrate in by a variety of processes. There are several options in which a planet could have a second chance at life. Could the study of these planets, looking at their atmospheric spectra, be done almost as a byproduct of studying them, looking for the things we've also talked about, like oxygen? Absolutely. So this is one of the key advantages of our approach, is that we don't need to build a new instrument. We can use existing technology,

it's future technology, but it's technology that is being built right now. And while we are searching for these signs of molecular oxygen, of methane, of other properties of the atmosphere that we care about, we can simultaneously place constraints on the pollution levels of these alien planets. So in particular, maybe if we find a planet which has signs of life, if we just want to measure its atmosphere very precisely, we don't have to do anything extra in order to place constraints on the pollution. We just have to study the data carefully. And that's one of the points that we made in the paper. It doesn't require an extra sort of observational effort.

Now, if the levels of pollution are low on this planet, if they're like, say, at the levels of the Earth and not 10 times higher, then we will require something extra. We will basically have to use next generation technology in order to be able to detect them because the signatures will be very, very faint. But if they're at high levels, like 10 times the levels of the Earth, then a very detailed measurement of the atmosphere should reveal it, even with the James Webb telescope. That's Henry Lin of Harvard. He has more to tell us about this new kind of SETI when Planetary Radio returns in a minute.

Hi, this is Casey Dreyer, Director of Advocacy at the Planetary Society. We're busy building something new, something unprecedented, a real grassroots constituency for space. We want to empower and engage the public like never before. If you're interested, you can go to planetary.org slash SOS to learn how you can become a space advocate. That's planetary.org slash SOS. Save our science. Thank you. Your name carried to an asteroid.

How cool is that? You, your family, your friends, your cat, we're inviting everyone to travel along on NASA's OSIRIS-REx mission to asteroid Bennu. All the details are at planetary.org slash B-E-N-N-U. You can submit your name and then print your beautiful certificate. That's planetary.org slash Bennu. Planetary Society members, your name is already on the list. The Planetary Society, we're your place in space.

Welcome back to Planetary Radio. I'm Matt Kaplan. There's more than one way to search for extraterrestrial intelligence. We've talked about radio beams and flashes of laser light in many past shows, and now for something completely different, courtesy of lead author Henry Lin at the Harvard-Smithsonian Center for Astrophysics. Henry is telling us about simulations or models that indicate the soon-to-be-launched James Webb Space Telescope could detect very high levels of certain industrial pollutants. This obviously opens up the question, why would an intelligent civilization, present company excluded, I suppose, allow their atmosphere to reach such incredibly high levels of pollution that we would be able to detect with the JWST. Doesn't seem very smart. It doesn't seem very smart. So I like to say that,

you know, we're searching for intelligent life, but maybe what we will end up finding is unintelligent life. Similarly, maybe an alien civilization with their own SETI program that is more advanced than us will aim their telescopes at Earth, and we'll see signs of industrial pollution and say, oh, there's no intelligent life on that planet. They must have it all wrong. So there are a variety of scenarios that I can imagine. Of course, these are all speculative. One is the scenario that's basically happening on Earth, which is that the aliens have trouble

convincing their alien congresses about the reality of environmental effects associated with industrial pollution. I can't believe there's any government body that would be so ignorant. That sounds crazy, right? Doesn't it? Second possibility that I can think of, which is more optimistic, is that they're trying to warm up their planet deliberately. And this could be the case because they're orbiting a white dwarf, which is slowly cooling with time. So maybe they're feeling kind of cold and they want to warm up. Another possibility is perhaps they've found a planet that's just on the edge of the habitable zone.

It's a little bit too cold for their tastes, and they want to warm it up to make it more hospitable. So there have actually been discussions about how we would terraform Mars. How could we terraform Mars in order to make it more hospitable to life that we find on Earth? And one of the possibilities that people have discussed is by dumping CFCs. In particular, a few of the CFCs, like the ones that we considered, are very, very efficient at warming up the atmospheres. It's rather ironic, actually, because for our studies, we're interested in the molecules which have the biggest impact on the light coming from the sun. Well, those are also the molecules that have the biggest impact

in globally warming the planet. It's not necessarily a negative scenario. Maybe they're not unintelligent like us in which they cannot control their industrial pollution problems. Maybe they're doing it deliberately because they're so advanced and they've been able to convince their alien congresses about the importance of space research or colonization or space exploration. So I can see two possibilities. So these are CFCs, you know, the kind of stuff that we've had trouble with on this planet with interfering with our ozone layer protection, but could be used very beneficially in a situation like that. I mentioned to you before we started recording that there was a story I've been waiting for the opportunity to tell on this show

for years and years. It comes from a friend of mine who we've lost since then, a very funny guy named John Donan. And John once came up with a concept. He called it Hot Rods of the Gods. And this was the theory that ancient alien teenagers

used the earth as their drag strip and that life on Earth evolved from their hydrocarbon emissions. So I doubt that that would happen with CFCs. Yeah, so I don't know about that scenario. Neither does anybody else. The whole stuff about panspermia is very interesting. Yeah, isn't it? This would be a twist on panspermia that I don't think anyone has considered. You spend a great deal more time studying very different objects or actually clusters, galactic clusters. Was this sort of a fun distraction? I mean, which would you rather

look at, the very, very large or the quite tiny planets that might harbor intelligent life? Yeah, it's funny. You know, in astronomy, we think of planets and stars as tiny things, and we think of clusters of galaxies, which have masses like many, many times the mass of the Milky Way as, you know, large things. I personally find both of them equally fascinating. The beauty of physics is that it works on so many scales. The same physics that we use to study the subatomic is relevant, actually, in studying the physics of galaxy clusters because galaxy clusters actually originated, in some sense,

from quantum fluctuations in the early universe. It's all sort of connected, and it's not connected in some sort of spiritual way. It's connected in a very precise mathematical way. And I find that very fascinating and satisfying. Like my mentor always says, you have to balance doing quote-unquote conservative science with quote-unquote risky science. You should also do things which sound maybe a little bit crazy at the time, keeping in mind that many of the things that sounded crazy at the time ended up becoming totally mainstream, like inflation, like the Big Bang cosmology. There are many, many examples of people who at the time were derided.

The scientists at the time said, oh, that's crazy. That's like totally improbable. Now they're totally accepted. Doing exoplanet research is incredibly fun. A large part of the reason why it's so fun is because it's so risky. You have no idea what you're going to discover. And I can't wait for the surprises that are ahead. Henry, I hope that you will have a chance to do another TED Talk. I very much enjoyed the one you delivered at the TED Youth Conference on galactic clusters. And I think this would be

another terrific topic. I do want to mention now that we're this far through the conversation, you are in what year at Harvard? I'm a rising sophomore, so I still have a little bit of ways to go before I graduate, I guess. And we can wish you a belated happy 19th birthday. Henry, you have opened a lot of eyes here, and possibly also with that fact, and certainly hope that you have a very long and revealing and enjoyable career ahead of you. Thank you so much. It was great talking to you. Henry Lin, he is a Harvard undergrad and the lead author of the paper we've been talking about, which is going to be published in the Astrophysical Journal Letters. It is called Detecting Industrial Pollution in the

Atmospheres of Earth-like Exoplanets. It is absolutely fascinating. And we'll put up a link to the abstract on the show page that you can reach from planetary.org slash radio. We'll put up a link as well to his TED Youth Talk, which I highly recommend taking a look at. And I recommend sticking around to hear this week's edition of What's Up with my friend Bruce Betts. It is time for What's Up on Planetary Radio. We've got Bruce Betts, the Director of Science and Technology, on the line. If you will grant me this, because I was such a huge fan of his, we learned not long before Bruce and I recorded for this week that Robin Williams is gone. I mention it because I was a tremendous fan.

I saw him live a couple of times. He was a guy who loved science. He loved science and space stuff and could do tremendous humor about them. And so I just mark his passing and the world is a less funny place by far without him. Indeed it is. Sorry to start with a downer. Take us up into the sky. If you're picking this up shortly after it comes out, you can still catch some Perseids.

It's a broad peak. Perseid meteors looking like bright streaks of light going through the sky. It is near full moon, so a lot of interference from moonlight, but you can still catch some of the brighter ones. Peak is the night of the 12th and 13th, but again, pretty good for a couple days before and after at least. We've got an amazing conjunction of planets coming up, meaning they're really close together. In the pre-dawn sky in the east, you'll need to have a clear view low to the horizon. Not too long before dawn, the two brightest planets will be super close, 0.2 degrees apart, Venus and Jupiter, that's August 18th, the morning of August 18th.

And, of course, nearby each other for a few days before and after that. Wow. Very close, isn't it? 0.2 degrees? It's super-de-duper-de close, and particularly for the two brightest planets, it should be a pretty impressive sight. You're so charming when you use those technical terms. Yeah, well, hopefully I don't lose the audience. That was a joke. Not a very good joke. charming when you use those technical terms. Yeah, well, hopefully I don't lose the audience. That was a joke. Not a very good joke. Okay, on to this week in space history. 1977,

the first glide test of the sort of space shuttle Enterprise. I was standing on the salt flat, the salt bed at Edwards Air Force Base. Pretty exciting. But it didn't hit you or anything bad, right? No, but the chase planes, the T-38s, just about knocked us down. They were so loud. More recently, in 2005, this week, Mars Reconnaissance Orbiter was launched. And still doing great science nine years later. On to... Random Space Fact! That's good.

I'm sorry I didn't get a celebrity random space fact from our guest today, but I do have a random space fact from a listener later, but do tell us yours. After accidentally breaking, since we'll be talking about lunar rovers, after accidentally breaking a lunar rover fender on Apollo 17, one of the astronauts, ground controllers devised a plan that the crew implemented, fabricating a new fender out of sturdy maps, duct tape, and clamps. They really use duct tape? They really do. They really did. That's wonderful. Duct tape on the moon.

Oh, they really did. That's wonderful. Duct tape on the moon. We move on to the trivia contest where I asked you about lunar rovers. Approximately how long was the Apollo lunar roving vehicle? How'd we do, Matt? I'm going to zip right into this because we've got some funny responses. which came from, I believe, a first-time winner, Bruce Miller of COSCOB, Connecticut, who said that it was about 3.1 meters or a bit more than 10 feet, correct? Yes.

Excellent. Okay, well, Bruce, that got you a Planetary Radio t-shirt. I've got to go through some of these others. This one from Andy Krejci of Santa Cruz, California, nice little coastal town here in our state. You know how our people love to give us other units, right? Oh, yeah. So he gave it to us in AU, 2.0722 times 10 to the minus 11th. Here's one I'd never heard of, even though I know by the Mark Twain, 0.85 of a Mark Twain. Of a Mark Twain.

So it says, here is one not about the length, but an interesting comparison that came from regular entrant Stephen Coulter. Did you know that the lunar rover was about a quarter of the mass of Curiosity, the Mars Science Laboratory rover? It didn't have that heavy plutonium, I guess, in the rear. Here is the random space fact that I promised. This came from Dan Campbell, and he actually did call it an RSF. He says, although abandoned decades ago, the DMV, that's the Division of Moon Vehicles, is still trying to collect 43 years of back taxes from NASA.

Yeah, good luck with that. I'm glad you like that. All right, we move on to the next trivia contest. What two chemical elements both discovered in 1803 were both named after asteroids? What two chemical elements discovered in 1803 were both named after asteroids? Go to planetary.org slash radio contest. You've got until the 19th. That would be August 19 at 8 a.m. Pacific time, a Tuesday, to get us the answer.

Oh, and you'll win a Planetary Radio t-shirt. Cool. Okay, everybody, go out there, look up at the night sky, and think about sticks. Thank you. Good night. The band? No, the piece of a tree. Oh.

Well, then, you can't shake a stick at him. He's Bruce Betts, the Director of Science and Technology for the Planetary Society, who joins us each week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by the mostly non-polluting members of the Society, Clear Skies. Thank you.