Planetary Radio: Space Exploration, Astronomy and Science - Special Coverage of the Division for Planetary Sciences Annual Meeting

Episode Date: October 11, 2010

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Special coverage of the DPS meeting, this week on Planetary Radio. Welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. DPS is the American Astronomical Society's Division for Planetary Sciences. Hundreds of scientists come together every fall for the annual meeting of the division. The 42nd of these gatherings was in Pasadena, California, just last week. We'll take you to the convention center in a couple of minutes, right after Bill Nye begins our special coverage.

Hey, hey, Bill Nye, the planetary guy here, executive director of the Planetary Society. And this week on Your Place in Space, it's all about DPS. They had their big meeting in Pasadena, California, in the United States this week. And when this thing started, they all thought, well, we're going to look at our solar system. We're going to look at Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, all good. And we do. We got spacecraft on the way to Mercury, on the way to Venus. We've got Cassini orbiting Saturn. We've got all that stuff. But now everybody at the Division of Planetary Sciences acknowledges or admits or embraces the idea that we have to look at planets around other stars.

Not just our own sun, other stars. And coincidentally, this week, a big announcement was made that Gliese 587 G seems to have the right surface temperature to have liquid water. Now, if it had liquid water, maybe it will have life. Oh, my friends, if we discover certain gases in the atmosphere, certain chemistry on this planet orbiting this distant, distant star, it will change life on this planet. I mean, we'll still drive on the correct side of the street, depending which country you live in, but the world will change if we discover life elsewhere. So if you're looking for a logical place to look for, search for extraterrestrial intelligence, this would be one of the places, wouldn't it? It would affect the way we look at everything. It would, dare I say it,

change the way you look at your place in space. I get to fly. Bill Nye the Planetary Guy. By the way, Bill's Your Place in Space commentary will now be available as a separate stand-alone feature at planetary.org. When we visited the DPS meeting for a few hours, the halls were crowded with more than scientists. They had been joined by Southern California school kids who heard special lectures and visited exhibit booths. This is a website you guys can go to. I don't know if you want a card, a sticker, or one of the pretty pictures. Pretty picture. Pretty picture. Or you can take one of each if you want. Emily Lakawala wouldn't have missed DPS for anything. I caught her between presentations on the last day of the conference.

Emily, you've been here all week? I have. It's been a long week, but it's been really fun. Lots of updates from all over the solar system. So tell us about some of those, and I think you're going to start with an interesting new theory or hypothesis about Saturn's rings. Yeah, and this one actually grew out of some work that had been done on Jupiter. About a year and a half ago, Robin Knupp announced that Jupiter ate its young, that when it first started forming moons, it actually made quite a lot of large moons and ate all but the last four, and the last four are the ones that we see now.

Well, she's turned her attention to Saturn, and a similar process operated at Saturn, but with some subtle differences that she can use to explain how the rings formed. What happened was that Saturn formed a bunch of mid-sized and big moons, and most of them decayed into the planet. Saturn ate all of these moons. But what happened to the second-to-last large moon was very interesting. Its orbit started decaying toward the planet. It was a differentiated

moon that had an ice mantle and a rock core. And as it got closer and closer to the planet, the planet started stripping off the ice, which went into orbit around Saturn, generating a ring. But by the time it got down to the core and Saturn's gravity was able to start tearing apart that rocky core, the core got all the way down to Saturn's atmosphere and was eaten by the planet. So Saturn ate the rock part, but spat the icy part into orbit, creating the rings. And furthermore, some of that material migrated outward and condensed into some of Saturn's mid-sized inner icy moons, which have very low densities, like Tethys has a density less than that of water ice. So this is a way to explain that. So was this Lost Moon? Was this Titan's lost twin sister? Well, it could have been Titan's lost twin sister, and there may well have been a lot

of other twins, triplets, quadruplets out there, but all the rest of them were totally eaten by Saturn. You've got another story about moons in the outer solar system. This one's a bit more complicated, but worth telling, you say. That's right. Looking very closely at the colors of Saturn's moons, they're mostly very gray. They're made of ice.

But if you enhance the color pictures of their surfaces, you start seeing that several of them have these dark stripes on their equator, but only on their leading sides, the sides that face forward in their orbit around Saturn. And it's very obvious on Mimas, it's a little less obvious on Tethys, and you don't see it at all on Enceladus. And Polshenko started looking at these maps and figuring out a way that it has to do with Saturn's magnetosphere and the way that electrons spiraling around in Saturn's magnetosphere

color some moons that are closer to Saturn, but not other moons that are farther away from Saturn. And I just saw a talk this morning where Brad Dalton talked about seeing a similar pattern on Europa at Jupiter, except that the dark color band is on the trailing side, not the leading side, and that has to do with the different structure of Jupiter's magnetosphere. It's all terribly complicated, but it's really cool the way

that all the disciplines are coming together to tell this detailed geologic history of how the moons came to appear as they do today. Now, remind me, Mimas, that's the black and white cookie moon, right? No, that's Iapetus. Mimas is the Death Star moon. It's the one with the giant crater, Herschel. All right, let's go farther out in the solar system to Pluto and its companion.

You know, this is a planetary astronomy conference, so a lot of the talks are not about spacecraft data, but rather about what data the giant telescopes are returning on the things at the far reaches of our solar system. And some of the most interesting results I've seen have been on occultations of stars by some of these tiny icy objects in the Kuiper Belt, including Pluto and Charon, but also some things that don't even have names. And so we're getting at more detailed knowledge of the diameters and even the shapes of these bodies. We now know, for instance, from this conference that Viruna is not circular, spherical, but rather has an ellipsoidal shape.

And we're getting better numbers for their diameters, so we're getting sort of a better census of what's out there in the Kuiper Belt. Let's bring it back down a little bit closer to home. Talk about ongoing news, I suppose, from Rosetta. That's right. Rosetta recently flew past the largest asteroid that has ever been visited by a mission, 21 Lutetia, as Americans call it, or Lutetia, as the Germans call it. It's a big asteroid,

and now that they're taking the time to analyze the data that they got back from the mission, they're finding it's a body with a very complicated geologic history. There are parts of it are more densely cratered than other parts. There are landslides all over the place. Parts of it are covered with blocks

as large as 300 meters in diameter, but other parts are not covered with those blocks. They have figured out that it doesn't have any moons down to a diameter of about 60 meters, so all those blocks that got tossed up by impacts onto Lutetia didn't enter orbit. They all just came back down to the surface. So it's been fun to watch this story, and of course now Rosetta is about to enter hibernation for several years before it finally gets to its destination.

Comet 67P, Churyumov-Gerasimenko. Easy for you to say. Well, yeah, it's not so easy for people to say, so I actually heard it nicknamed Cherry Gary at this conference. I'm going to remember that next time we talk about Rosetta on the show. Like we said, you've been hanging out here all week. Has this been fun? It's always fun for me to meet and greet all the people in this community. Some of them are my friends from grad school.

Some of them I've just befriended through conferences or even through Twitter, actually. So it's always fun to put faces to names and actually get to interact with people in person and have a couple of beers over in the poster session. Running into a lot of readers of the blog as well? Absolutely. I'm always gratified to hear when scientists also read my blog and I hear that they actually use it to discuss what's going on in space missions

at their meet and greets on Fridays. And I'm sure everyone is envious of your free spirit t-shirt. I've been wearing lots of geeky space shirts this week. I'll have to do a post about those. Last thing, we'll congratulate China on the arrival of Chang'e 2 at the moon. That's right.

Chang'e 2 is now in its lunar orbit. It successfully launched on October 1st. It arrived in lunar orbit on, I think, the 6th, and it has now arrived in its science mapping orbit 100 kilometers above the surface. Eventually, they actually plan to take this thing into an orbit that at its perilune gets down to 15 kilometers above the surface, which is just astounding. That is, and that'd be something to see go overhead, wouldn't it? Emily, as always, thanks so much. We'll let you get back. The break is almost over. Delighted to see you, Matt.

Emily Lakdawalla, delight to talk to her face-to-face from DPS. She is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine. Emily wasn't the only person we talked to at last week's DPS meeting. We'll bring you more of our conversations in a couple of weeks, but we'll hear from two distinguished attendees today. Scientist and Administrator Lindley Johnson had flown out to Pasadena from NASA headquarters in Washington, D.C.

I'm the program executive for a couple of programs there. First of all, the Discovery Solar System Exploration Missions is the Discovery program, and then also for the Near Earth Object Observations program. That keeps me pretty busy. I'll bet. And the Epoxy mission, which is going to come up a little later on today's show, part of our weekly space trivia contest, that's one of yours. Yeah, that's one of the ones I help oversee for NASA.

Yeah, we're real excited about that mission. It's a reuse of the Deep Impact spacecraft, of course, and it will be encountering the Common Hartley 2 here in just a little under a month. So the final preparations are being done for that encounter. You gave away the answer, but that's okay, because everybody will have gotten their entry in a week ago by now. You said you've been to DPS all week. Yes, I got here Monday and I've tried to attend as many of the sessions as I could between continuing to work issues

back at NASA headquarters. It must be nice to get away, get to the other side of the country now and then and actually hang out with all the scientists. Oh, yeah. I always look forward to the DPS every year to catch up with how the research is going with all the programs and projects that NASA works with the academic community. Have you heard lots more evidence this week showing that these are exciting

times for a near-Earth object study? Oh, yes. I mean, the number of papers and the amount of information that's presented here at DPS on NEO research, small bodies research, has just continued to explode over the years. And I would say, you know, a good portion of the DPS program now is centered on asteroids and a lot of it on near-Earth objects. So is your sense that not only in the science community, but possibly also in the political and public communities, that people are beginning to realize that these are objects well worthy of study and maybe not just to protect ourselves?

well worthy of study and maybe not just to protect ourselves? Yes, I think that's true. Certainly the subject of NEOs over the last decade or so has expanded considerably, and the information has gotten out. People have had a chance to look at that information and understand more of the nature of these objects, both as important objects from the formation of the solar system to understand the evolution of the solar system, but as objects that could potentially threaten Earth in the future.

You know, impacts will continue to happen over the geological ages. But now being looked at as destinations for human spaceflight and potential sources of resources for the exploration of the solar system. You know, you just mentioned the next place that I was going to go with this, which is that outlook for a possible mission to an asteroid. Is that looking like it, more and more like it may become a reality? Well, there's a lot of homework still to be done on that, and that work is just really getting underway as to what it will take for a human mission to an asteroid. It will be a challenging task, every bit as challenging as the moon mission was the Apollo project back in the 60s, probably more challenging, quite frankly.

Any highlights from DPS that you want to mention? Well, I think one of the big things, and one that I've heard a lot of comments from, is the presentations that have been done on the data collected by the WISE spacecraft on solar system objects. The WISE mission was actually an astrophysics mission to develop an infrared background of the sky, but we've done some enhancements to its data processing that have allowed us to collect a great deal of information about solar system objects, and I think that has been a big splash here at DPS. We've featured WISE a couple of times on this show, and we look forward to doing it again.

That is really an all-purpose mission, looking out to exoplanets and right in toward our own planet at these NEOs. Yeah, it's become a survey of everything that's out there, not just the background sky. Headed back to D.C. tomorrow? Yeah, yes I am, first thing in the morning. Get a chance to relax with folks a little bit, I hope, this afternoon and this evening, and then head back to D.C. in the morning. Well, we interrupted you as you were catching up on email, and I'm sure

there's no shortage of that from NASA HQ, so thanks for taking a minute or two with us. No problem at all. I enjoyed doing it. That was Lindley Johnson of NASA Headquarters, where he oversees several Discovery-class missions. Lindley is also the Near-Earth Object Program Executive at the agency. When we return with more of our special DPS coverage, we'll learn how astronomers are beginning to discover what exoplanets are made of. This is Planetary Radio. I'm Sally Ride. After becoming the first American woman in space,

I dedicated myself to supporting space exploration and the education and inspiration of our youth. That's why I formed Sally Ride Science, and that's why I support the Planetary Society. The Society works with space agencies around the world and gets people directly involved with real space missions. It takes a lot to create exciting projects like the first solar sail, informative publications like an award-winning magazine, and many other outreach efforts like this radio show. Help make space exploration and inspiration happen. Here's how you can join us. You can learn more about the Planetary Society at our website,

planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan.

We continue our special coverage of the American Astronomical Society's Division for Planetary Sciences annual meeting. Mark Swain didn't have to drive far to reach the Pasadena gathering, but the subject of his research is not so conveniently nearby. Mark leads a team at the Jet Propulsion Lab that is beginning to discover the composition of planets that are still too far away to be seen. And we use telescopes like the Hubble Space Telescope, the Spitzer Space Telescope, and we use the exoplanet systems, those stars that have planets that go around them. We use the exoplanet systems where there are transits, so the planet appears to go either in front of or behind the star. We measure the system light curve,

so how the light from the star changes during that event, and we use that to try to extract some knowledge of the atmospheric properties of these planets. We live in amazing times that we have actually reached the point where we can begin to not just detect these exoplanets, 500 or more now, but see what they're made of. That's right. This is a very new area, so people have been doing this characterization only for a few years.

The way this works is that we break the light up into a spectrum, so just like a rainbow breaks sunlight apart and we see the different colors, we do the same thing with an instrument called a spectrograph. When we do that, each molecule absorbs light at unique colors. And so each molecule has a fingerprint. And so we make that spectrum during the eclipse sequence when the planet goes in front of or behind the parent star.

And we can see the pattern, the fingerprint that these molecules leave in the spectrum. But picking out that spectral information from the much more intense spectral information you must be getting from the star, is that the trick in this? Yeah, that's the hard part. These instruments that we're using were never designed to work in this regime. So to give you an idea of the contrast we need to measure, we need to make a measurement that's good to about one part in 10,000. The instruments really were designed to work at more like a part in 100. design new algorithms or a new mathematical process to calibrate the data,

remove the artifacts, and see that signal that's buried in the data. Two orders of magnitude. That's impressive. It's a lot of work. We do benefit quite a bit from the transits. And so what happens is we're essentially taking a difference of the light in eclipse and out of eclipse. taking a difference of the light in eclipse and out of eclipse. So the instrument may mess things up a little bit, but it more or less messes things up the same way. This is all just getting started. Bigger instruments coming. We talk about them on this show.

What are you most looking forward to in the next few years that's going to make your job easier and tell us more about these planets and maybe find one with, oh, something like oxygen on it. Well, we've got sort of three thrust areas that we're looking at in our group. So one is now trying to exploit ground-based telescopes. Traditionally, this exoplanet characterization and detection of molecules has been done from space. But three groups now have started to do this from the ground, and our team is one of them. The advantage of the ground is that there are some very big telescopes, and that offers some great advantages. The second area that we're looking forward to is JWST.

When JWST is launched— That's the James Webb Space Telescope, of course, which we've talked about. Yeah, that will be a fantastic resource for doing these transit spectrum. And finally, our group and other groups are looking at purpose-built exoplanet space missions. And the advantage with a purpose-built instrument is you get to design it for stability. And all these measurements depend on achieving, either through initial design or through calibration, exquisite stability. What are your thoughts about this very recent announcement of the first near-Earth-sized planet in, we'll call it, the Goldilocks zone? Well, our team found that really exciting.

That's not a transiting planet, which is a bit of a disappointment to us, because we would love to try to take a spectrum of its atmosphere. And we do need a transiting planet at which is a bit of a disappointment to us because we would love to try to take a spectrum of its atmosphere. And we do need a transiting planet at this point to do that. But the fact that this was found at all, as the authors point out in their paper, really is a very good indication that there are probably many more like it out there and nearby. So it will lend itself to characterization. Mark, you were part of the Planetary Society's big event that helped to kick off DPS, the public event at Caltech, on Monday of this week, and I didn't get to go to that.

You got to talk about this stuff? We did talk about that. There were four presentations given as part of that kickoff event, and they started with formation to finding planets and finally to characterizing with a focus on these molecules, which we'll ultimately use to determine if life is present. You've seen increasing public interest in this idea of other worlds circling other stars, and maybe we're not too far from finding one like our own? I think that's right. I understand from the Discovery Channel's lead science reporter

that their website was utterly overwhelmed when this Gliese 581G Earth-like planet was announced, that there was just a huge response from the public, and I think that's very exciting. Exciting times ahead. Indeed, indeed. I look forward to maybe 10, 15, 20 years hence when we'll be able to really start to answer that question, are we alone? Amazing times indeed. Mark, thanks so much. It's good to have you back on the show. Thank you very much. That's Mark Swain, a research scientist at the Jet Propulsion Lab, not far from the Pasadena meeting of the Division for Planetary Sciences. We'll hear more from scientists at DPS in an upcoming episode,

but you can read more about the just-completed annual meeting in the Planetary Society's blog at planetary.org. And that's not all. You can also learn how our Emily Lakdawalla became part of the International Space Alien cover-up. Really, it's all in the blog. There is one more person I caught in the giant lobby of the Pasadena Convention Center. Stand in the hallway at DPS, ready to wrap up our special coverage of the DPS conference here in Pasadena, California.

And standing with me as we hear the sirens go by outside. I've got to go. Really? That's all right. Just face away from the window. You'll be all right. No, they've moved on. Okay.

Never mind. Bruce Betts is the director of Projects for the Planetary Society, and he's going to tell us what's up. You've been hanging out here all week, haven't you? Yes, I've been hanging out here all week. There's been all sorts of good, neat, new planet stuff. My great regret is that I missed the Planetary Society event Monday evening at Caltech. Yeah, we had a great public event.

Lots of great exoplanet speakers that we co-sponsored with the Keck Institute for Space Studies, KISS, and also the DPS. So tell us about the night sky. In the night sky, we've still got Venus, if you look after sunset, hanging out in the twilight low in the west. And Jupiter over in the east in the early evening, up bright and still Uranus if you pull out those binoculars or a small telescope, hanging out not too far from Jupiter. So it's a planetary evening these days. Also, the answer to our trivia question we'll be announcing shortly, where epoxy is going. Comet Hartley 2, technically 103P Hartley 2, sort of visible. It's got one of those

magnitudes that makes you think it's naked eye, between five and six. But because that's spread over a big area of fuzzy blob, it's actually even a little bit challenging in binoculars. But certainly with a telescope and probably with binoculars. It's in the northern part of the sky, so probably not too doable for a southern hemisphere. It's near Cassiopeia. Try to check it out in the next week or two. It has got its closest approach to Earth at just 0.12 astronomical units, 11 million miles or 18 million kilometers away on October 20th. That, thanks to one of our listeners writing in for the trivia contest, Craig Gurnay. Gurnay, actually, but thank you, Craig. Well, there was no pronunciation on this one. I know. He knows I know how to pronounce it. Okay, Craig Gurnay.

What else you got? Oh, should I crank up the full-blown thing in the hallway? We should go over there and get those kids to do it. Why don't we do that? Okay. We'll just pick up over there. Really? Yeah, why not? So we've actually moved over in the hallway at DPS over to where all these kids were having lunch for Marshall Fundamental School right here in Pasadena. Are you ready to let them use your line? I am. I'm excited about it. Okay, guys, you ready? One, two, three. Random Space Facts! Nice. Wow, that was brilliant. Thank you. Thank you so much. Okay, now he's going to give us a random space fact. The WISE mission, as their Neo-WISE part, is actually the number one

discoverer of comets and near-Earth objects in 2010. That's impossible. One spacecraft? One spacecraft and all the people that operate it. Yes, they've discovered 120 near-Earth objects, as well as literally tens of thousands of objects out in the asteroid belt. Was that a good random space fact? Yes! Good audience. Okay, we're going to go on to the trivia contest now and find out who won. All right, we asked you what is the name of the comet that the epoxy spacecraft will encounter

and what date will it encounter it on? How did we do, Matt? We got a lot of great answers, and our winner, I'm very happy for him and happy to say that after five years of off and on putting in an entry, trying to win the contest, Stefan, Stefan Fischus in Stuttgart, Germany, got the right answer and was chosen by Random.org this time. He said Hartley 2 is the comet that POXxy will be flying by on November 4th. Just, what, maybe three weeks after people hear this program this week. Yeah, it should be very exciting. So all of you out there in Radioland and Marshalland,

pay attention on November 4th to the encounter with Comet Hartley 2. And I do want to mention David Kaplan did not win, but he said that he did want to point out that epoxy won't quite come close enough for the epoxy to allow it to stick to the surface of Hartley 2. Anyway, we're going to send Stefan a Planetary Radio t-shirt. What do you got for next week? All right, for next week in the theme of DPS, where will next year's DPS meeting be held? That's the Division of Planetary Sciences, not the Dudley Proper School or anything else. The Division of Planetary Sciences of the American Astronomical Society, 2011 meeting. Where will it be held? Go to planetary.org slash radio.

Find out how to enter and take your shot at winning a Planetary Radio t-shirt. None of you guys know where it's going to be next year, do you? No. Okay, well, you can look it up and maybe you'll win Radio t-shirt? None of you guys know where it's going to be next year, do you? No. Okay, well, you can look it up, and maybe you'll win a t-shirt. You've gone until the 18th of October, October 18th, at 2 p.m. Pacific time, to get us that answer. And we're done. All right, everybody, in honor of our helpers here,

everybody go out there, look up at the night sky, and think about eagles. Eagles! Thank you, and good night. Let's hear it. He's Bruce Betts, the director of projects for the Planetary Society, and he joins us every week here for What's Up. Join us next week as we prepare to hunt for gravity waves

with LISA, the Laser Interferometer Space Antenna. Planetary Radio is produced by the Planetary Society in Pasadena, California and made possible in part by a grant from the Kenneth T. and Eileen L. Norris Foundation. Clear skies. Thank you.