Planetary Radio: Space Exploration, Astronomy and Science - Emily Lakdawalla Reports on the Latest Planetary Science

Episode Date: October 10, 2011

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Music Emily Lakdawalla with the latest planetary science this week on Planetary Radio. Music Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. We also take you to South Africa and France this week. Bill Nye has just returned from the International Astronautical Congress in Cape Town, while Emily is getting over her jet lag after visiting the annual gathering

of the American Astronomical Society's Division for Planetary Sciences. Ms. Lakdawalla is the mistress of the Planetary Society blog, of course, as well as the Society's Science and Technology Coordinator. She will give us a special extended report on her week in Nantes, an inland port near the west coast of France. This year's DPS meeting was combined with the European Planetary Science Conference. Later today, Bruce Betts and I will give you a chance to win The Beauty of Space, the new book from the International Association of Astronomical Artists. First, though, let's visit with Bill Nye, the science and planetary guy.

Bill, welcome back from South Africa. We got just the barest introduction to your trip there last time, but now you're back, and I hope that you can give us a little tale about that Congress you attended. Yes, the International Astronautical Congress, which is the annual meeting of the International Astronautical Federation. And people present technical papers. People write all kinds of papers about all kinds of things. And these people come from all over the world. I heard a fascinating talk about why astronauts don't last that long in space.

They have to exercise constantly, sometimes four hours a day. People study the mitochondria of cells. Apparently in zero G, the mitochondria of your cells don't look that good. So you just don't operate that well. And after a few months, you've had enough. It's fascinating. And then there was a presentation about nuclear propulsion. It's back on the boards.

Then the head of NASA, Charles Bolden, was there. The head of ESA, the European Space Agency, Monsieur Dordain, was there. And these guys get together and they talk about stuff. The Russian Space Agency, people from all over sharing this vision of an optimistic future with space exploration. It's really a great thing. And we as the Planetary Society, we're well represented. I did a little talk at the education session, just reminding everybody that this is important work we do in that we have to be leaders with regard to understanding the Earth's climate and with regard to proper utilization of our resources. Let's not squander money. Let's do the cool stuff with the money we have. It was good. It was very well received. You were saying that even the host country, South Africa, now has a

space agency? Yes. I got to tell you, Matt, I kind of thought they had one. You know, they have several weather satellites and communication satellites that are in stationary orbit above South Africa. Well, now they opened or started their own space agency, SANSA, the South African National Space Agency. And the representatives of SANSA were very impressive, very competent people, both the space scientists or the engineers and the organization, the people that are running it from within. You need that. You don't want inefficiency in your administration. So I'm very excited that South Africa has a space agency. Come on. It inspires everyone all over the world, space exploration. So it's really good to be part of it. And it's exciting for the Planetary Society

to be so present, so well included. Bill, I think that'll do it for this week. Thanks very much. Thank you, Matt. Thank you. Hi, everybody. Space exploration brings out the best in us, and it is always good to talk to you. Let's change the world.

Thanks, Matt. He's Bill Nye, the science and planetary guy, executive director of the Planetary Society. We'll be checking in, actually a long visit this time, with Emily Laktawalla, just back from yet another international conference. That's just a few moments away. Emily, welcome back from France, and congratulations. I saw a video of you, not a very good video, but there you were down on the stage at the annual meeting of the DPS, accepting your award.

Remind us, what was that about? Well, that was me accepting the Jonathan Eberhardt Prize for Journalism in Planetary Science, which is given out by the Division of Planetary Sciences at the American Astronomical Society, which is a mouthful. That's why everybody calls it DPS. It was great. It's a prize that's given out annually. It's the third time it's been given by the scientific committee from the Division of Planetary Sciences for explanation of current research to the public. So it was a great honor to receive it. And I have to say very good for my ego, because all week long, I was getting scientists approaching me

telling me how much they love the blog and how they read it. I even heard from several people from SWERI from the Southwest Research Institute, who apparently every Friday, they have donuts and talk about new happenings in planetary science. And I guess my blog is a frequent topic of conversation. So I want to give a shout out to the Swery guys. I bet it's up there on the PowerPoint screen or the projection screen as they eat those donuts. I wouldn't be a bit surprised. Well, I know also that there was an enormous amount of science revealed because I was just inundated. What a flood of press releases came out of this meeting. I'm hoping that we can take a few extra minutes today just because there is so much to talk about. Can we maybe start with Vesta?

Yeah, you know, Vesta was of great interest to a lot of people attending the conference, and I think it was kind of interesting. You know, they had a whole day session on Vesta, and everything is just so preliminary. Chris Russell called it the smallest terrestrial planet, which the IAU may not agree with. But it's true. What he meant by that is that it's a world right in there with Earth, the Moon, Mars, Mercury, and Venus that has a complicated and lengthy geologic history. They looked at crater counts.

They dated the northern hemisphere as being about a billion years older than the southern hemisphere. They saw multiple generations of different angled grooves. They saw landslides crisscrossing each other. There's a great number of things to see, and it's still kind of difficult to tear it all apart and kind of build a story about what Vesta is. So it's going to take a long time to puzzle this out, but the first images are always really exciting to look at. Other objects of that type out in space, I'm thinking actually of a comet, Hartley 2, which came up for some discussion. That's right. You know, there were two exciting

comet flybys within the last year, the Temple 1, which we had actually seen once before, and then Hartley 2, which is this tiny dog bone shaped comet, one of the smallest that's been visited by a spacecraft. And it too had just such a diverse landscape and chemistry that it's taken the scientists a little while but of course now they've had longer to look at their data and one of the more exciting conclusions is that the two lobes of the dog bone have distinctly different compositions so what we're probably looking at is two things that were formed separate in separate locations in the solar system and sometime in their history, they coalesce into one body. And so we've got, you know, it's a double comet.

It's got one that's much richer in carbon dioxide and one end that's not. And as they looked at the comet rotating, even from a distance, you could tell that only the smaller of the two lobes was spitting out huge fountains of carbon dioxide. So it's very unusual that the thing is a different composition on one end than it is on the other. Can I, from my extremely unqualified position, speculate? I mean, when I first heard that these had very different compositions, I thought, man, it looks like two things just smacked together and started to come apart,

but kind of froze. I mean, is there a thought of how these might have actually coalesced? Well, it's, I mean, the solar system is a dynamic place. And depending on where things are in the solar system, when they come together, they either smash and break each other apart, or they don't have enough energy to do that, and they join up. And then in the asteroid belt, things get even more complicated, because solar effects tend to accelerate the rate at which they rotate, and that tends to fission things apart again. So it's all kind of a mess of things coming together and pulling apart. And these bodies, although they're made of very ancient material, the component grains are very ancient,

the bodies themselves may actually only be a couple hundred million years old, which for geology is a baby. So many forces at work and so much left for us to understand. Let's go to another object out there that might be sort of in the class of asteroids. In fact, a lot of speculation that it was an asteroid. What news was there of Phobos, Mars' moon? Yeah, Phobos has been the topic of a great deal of study by Mars Express recently, because as it's gone into its mission extension, now they're getting ready for the Phobos Grunt mission, which is supposed to be

launching in the end of November, actually beginning of November. And so Mars Express has been taking advantage of its unusual elliptical orbit. It's the only spacecraft in orbit at Mars that can see all sides of Phobos. And so they've been encountering Phobos repeatedly and getting very good, the best images ever of all sides of it. You know, there's a lot of speculation about what might have caused its grooves. There's ideas that there may be fractures, that they might have had something to do with stichne. And I saw a very convincing presentation by a scientist who's looked at all of these Mars Express images. He came up with a number of observations about things that are true about all of the grooves. For instance, the grooves come in families. They're in parallel sets. If you look at Phobos

from the right angle, they're absolutely linear, which means they basically slice a plane through the asteroid, and yet there's intersecting sets. They're at all different angles when you look at the leading side of Phobos, the side that faces forward in its orbit. But every single plane, or at least the family of planes, crosses through Phobos' center. And what that means is that if you look at the sides of Phobos, the anti-Mars or pro-Mars side, there all the grooves are parallel. And this and a number of other observations that he made suggest to him that what these grooves actually are is strings of secondary impact craters from very, very large impacts on Mars, probably oblique ones that tossed strings of melt that

froze into strings of beads of impact melt that all crashed into Phobos. They were all moving in a parallel direction when Phobos just wandered through this curtain of impact material. And that it only probably happened, he said, there's about a dozen sets of these grooves. So it's actually a pretty rare event. It only happened 12 times since Phobos has been captured. And that Stickney crater, that really, the image that you've got, and you can also clearly see these grooves that divide this moon up into planes, it really took a chunk out of that moon. It did, and, you know, every asteroid seems to have one of these impact

craters that's very large. It seems like if it were any larger, it might have disrupted the asteroid. And that's actually reminding me of another interesting talk that I saw that was looking at craters on Lutetia and Staints, which are the two asteroids that the Rosetta spacecraft visited. And both of them, too, have a single very large impact. And the scientist who was giving that talk basically said, taken together, you know, all of these seem to have larger impacts than you would predict from what we know about the asteroid population. So it seems quite likely that there are actually more asteroids in the five to hundred meter

size class than we thought. And that's a size that we generally do not observe from Earth unless they pass very close by. So it's kind of an invisible part of the solar system. So that was an interesting talk as well. Stay tuned for more from Emily Lakdawalla about the just completed Division for Planetary Sciences conference. This is Planetary Radio. I'm Robert Picardo. I traveled across the galaxy as the doctor in Star Trek Voyager. Then I joined the Planetary Society to become part of the real adventure of space exploration.

The Society fights for missions that unveil the secrets of the solar system. It searches for other intelligences in the universe, and it built the first solar sail. It also shares the wonder through this radio show, its website, and other exciting projects that reach around the globe. I'm proud to be part of this greatest of all voyages,

and I hope you'll consider joining 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 t-shirt. Our nearly 100,000 members receive the internationally acclaimed Planetary Radio. I'm Matt Kaplan. We hear from Emily Lakdawalla every week, but now and then,

the Planetary Society's Science and technology coordinator deserves a few extra minutes. This time she's giving us a taste of the amazing announcements made at the annual meeting of the American Astronomical Society's Division for Planetary Sciences in France. We've already talked about a big asteroid, a moon of Mars, and a weird comet. Well, let's move in much, much closer to the sun to an object that, as far as I know, everyone still regards as a planet. A lot of talk about this at DPS, and you covered it in some detail in the blog. The MESSENGER team actually published their first scientific paper since going into orbit at Mercury last week. And so there's a set of press conferences about that.

But they also had a lot of new stuff to talk about at this meeting. And I have to say that the thing that excited me the most is something that they haven't published yet because they're not ready to. And that's their first topographic map of Mercury. They have a laser altimeter just like Mars Global Surveyor did. Theirs was called MOLA. Lunar Reconnaissance Orbiter has LOLA. And these laser altimeters, you know, they fire laser pulses and they listen to the reflections. Three million pulses. So they ping the planet that many times, I read. Yeah, three and a half million pulses. And not only that, but they get more than one range per pulse. So they actually have six million points measured

across the surface. I was going to ask you to explain that, how they get two measurements out of each little ping. I can't say I've looked at that in detail, so I don't quite understand. But it's a pulse, so it might be that they get reflected energy from more than one part of the pulses. I don't really know. But the point is that they have six million measurements, although something to keep in mind is that the thing only works in the northern hemisphere of Mercury, because MESSENGER's

orbit is very elliptical. And MLA can only range up to 2,000 kilometers. The orbit gets down to about 1 or 200 kilometers and gets out to like 22,000. So they only have this topographic data set for the northern part of Mercury. But it's really beautiful. And I think it's going to do just as much to revolutionize our understanding of Mercury's geology as it has done for Mars and the Moon with the slight difference that we actually didn't know a whole lot about Mercury's geology before Messenger actually got there. So there's a little less history to overturn than there was with Mars and the Moon. The topography is beautiful.

It shows us, for instance, that there is a northern lowland on Mercury. There is this floodplain of lava, huge voluminous flows of lava with beautiful channel features. And it actually flowed across the landscape and scoured the landscape and eroded teardrop-shaped islands. And it's all lava that covers like 6% of the surface of the planet. It's all a very low elevation. It's about two kilometers below the mean elevation for Mercury. And this was an absolutely enormous volcanic event. And so that is like a lowland. But then when you look at the topography, you see that there's this broad topographic rise in the middle of it that you totally can't see in the images. It's utterly invisible. But once you look at the topography, you can see it very clearly. And then even more exciting is that they've also developed this gravity map. And gravity is kind of an esoteric

data set. It's a little difficult to understand how you get it and why it's important. But basically, they do very precise radio tracking on the spacecraft. And if there's a little extra mass under a part of the crust, then the spacecraft gets tugged toward it a little bit faster, and then it lags behind in its orbit after it passes over the thing. And so you get a map of where there's little bits of extra mass under the surface. It's a Doppler measurement, right? Yeah, it's a Doppler measurement. And so you tend to see, like on the moon, it's very common that large impact basins

are, it's kind of counterintuitive. They're places where the mass is actually higher because higher density mantle has flowed into the space that was left by the crater and kind of pushed up the floor. And so you actually have more dense material underneath the floor of very big craters than you do under the rest of the crust. They're called on the moon, they're called mass cons, you know, mass compensation. And they see a few of those on Mercury. There are places like Caloris Basin, the largest impact basin, practically the largest one on the solar system, has a very large gravity mass underneath it. The weird thing about Caloris is that it's almost invisible in topography. There's a little low bit of topography around its rim, but nothing

that would make it really stand out topographically. So almost all of the topography that was made when the Caloris Basin formed has been erased by just the mantle kind of flowing into the gap over time and lifting up the floor of what used to be a deep impact basin. And they can actually tell that by looking at some craters that formed on the floor of Caloris before this mantle flow had happened. And now you can see that the craters on the edges of Caloris are actually tilted outward toward the outside of the basin because the floor in the middle of the basin is bowed upward. So there's all this amazing history that you can read from the topography and gravity,

and they're just getting started. They don't have the data set published yet because one complication of having a northern lowland is that it messes up your gravity field, and you need to understand the gravity field before you can understand what areas of topography are high globally and what are low globally. And so the two feed into each other, and they're just not yet, they haven't disentangled those two effects yet to be able to be confident enough to publish their maps. But that's coming. So is it safe to say that Mercury really has surprised those two effects yet to be able to be confident enough to publish their maps. But that's coming. So is it safe to say that Mercury really has surprised us? It seems to be quite different from any other rocky body in the solar system.

It really has surprised us. And I think, you know, probably on reflection, it's no surprise to anybody that a world this large has a complex geologic history that's not the same as other terrestrial planets. But the nature of that complex geologic history has been a great surprise and I think is going to continue to be very exciting for many years. So many more topics we could talk about. Let's just pick one in the outer solar system, and that's Saturn. You had an image of, and I guess there was discussion,

of this huge storm that is just about circling that planet. And this storm, it's a really cool story because, of course, it's on Saturn and we have a spacecraft out there that's Cassini. But most of the story of this storm was not told by Cassini. It was told by amateur astronomers. It was amateurs who first notified people about the storm. They first noticed it forming in early December of 2010. And it's amateurs who've been tracking it ever since. You know, it actually took the Cassini team a while to be able to develop new sequences to tell the spacecraft to study it. Some of their instruments only had very limited chances to study it, while others like the radio

instrument basically works all the time. So they've been hearing a ton of lightning from this thing. The storm is continuously generating so much lightning that the storm has produced that it's actually irradiated as much power as all of the radio emissions from the rest of the planet. So the storm first showed up as a little dot in early December, and it just grew and grew, and Saturn's winds sheared it out eastward while the storm continued to be puffing up material. It looks like it's water ice crystals from below. be puffing up material. It looks like it's water ice crystals from below. The whole thing, the tail eventually wrapped right around the planet and underneath the original storm. But the tail developed to this dark center. And once that dark center got all the way around the planet and collided with the head, the head split into three little storms and then it just disappeared. And that happened in the middle of June and now the storm is completely gone. So it was just about

an eight month, seven or eight month event. These kinds of things have actually been seen before they've I think there have been six of them. This was the sixth one since 1903. And it's it's Earth based telescopes that track these things. Because even with Cassini there, even with Voyager flying by during one, those are only very limited number of data point points. And we really need Earth based telescopes looking at the whole globe of Saturn to track these events day in and day out and discover how they develop. Well, tip of the hat to all the amateurs who participated in that and do so much more to advance planetary science. And I wish we had more time to talk about this annual meeting of the Division for Planetary Sciences. We're going to have to tell people, take a look at the blog

entries that you submitted from there last week. Emily, thanks so much once again, and we'll talk to you again next week. All right. Thank you, Matt. As always, Emily is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine. And she spent last week in France, not just getting the award that we talked about at the outset of our conversation, but gathering up all of this amazing science that was revealed at that meeting. We'll be back to reveal some more things when we talk with Bruce Betts for this week's edition of What's Up.

Time for What's Up. Bruce Betts is the director of projects for the Planetary Society, and he's on the Skype line. You weren't at, you're not currently at any international or interstellar conferences like Emily and Bill were last week? No, no, I was not. Although the week before, I spent the whole week in two different local conferences. Yeah, we talked at one of those. But no, I wasn't the exotic traveler to two different other continents like our brethren. Some people have all the luck, and I'm talking about you. Exactly. Congratulations, Demily.

Can't remember if I've said it on air for her cool award from the Division of Planetary Sciences of the American Astronomical Society. Very cool. And we talked a little bit about that in her extended interview today that we just finished. What's up? Well, we've got Jupiter still dominating the evening sky over in the east. Check it out on the 12th, 13th, or 14th. You'll see it near the bright moon. You'll have two bright objects over there.

But you can check it out anytime over in the east in the evening. Also, I rarely mention these, but Uranus and Neptune are both in places you can see them nicely in the south and southeast by mid to late evening, but you're going to need to pull out at least the binoculars, possibly the telescope, and find a viewing guide online to tell you exactly where you look. But I point out they are up if you want to go hunting for the dimmer planets. And I just mean in brightness, not intelligence. And then Mars rising a little after midnight in the east, high overhead before dawn, getting brighter, but still not totally bright, having its characteristic reddish appearance.

We move on to this week in space history. It was in this week that the Chinese launched Shenzhou 5 in 2003, providing their first Chinese astronaut. It was this week in 1947, the first official supersonic flight. Glamorous Glenis. And in 1968, the Apollo program got back on its human feet with Apollo 7 launch. We did have to recover there,

and recovered awfully well, I would say. So nice stuff to remember. Thank you. Good ones. Yes, indeed. We go on to random space facts. I didn't know you could do Peter Lorre. Rick.

Rick. Rick. Help me. Oh, yours is better, I think. Wow, mine's pretty bad, but I think you're right. Oh, well, that's not important right now. What is important is that there are 16 moons in the solar system larger than the largest asteroid Ceres, or dwarf planet, depending on your tastes. As big as Ceres is.

I mean, that's surprising to me. Yeah, that's what I strive for in these random space facts. And succeed. A lot of big moons out there. Big trivia. Big trivia. Big trivia. I asked you how many days did URs, the Upper Atmospheric Research Satellite, or at least that's what I thought it was called, spend in space? How did we do?

Well, it turns out, first of all, that you were wrong. Wrong, wrong, wrong. And we got this from Randy Bottom of Brighton, Ontario. Randy insists that it stands for Unidentified Awesome Radio Shirt. That's quite possible. My bad. But the one that you were talking about,

how long was it up there? Our winner this week, first-time winner, one of our friends out there in Poland. I'm sure I'll get this wrong, but it looks like Legnica, Poland. It's Michalina Stefaniak. Michalina Stefaniak. She came up with 7,314 days. Now, we probably would have needed to accept a couple of days either way on that, because it all kind of depended on where you were counting from. But I think that's good enough to get her a shirt? Yeah, no, there's a little slop, and I perhaps should have been more specific because it

did launch aboard the shuttle, so it went into space, but it didn't fly separately until after they got up there. So anyway, no, that sounds good, the basic range of 73-14 to 73-17, that kind of thing. Congratulations, Mikalina. And we just have one other that I want to mention because everybody always says, I think you said that UR's was about the size of a school bus. Mark Detweiler was quite

concerned, maybe you can put his mind at ease, could this have been a magic school bus adventure that went terribly wrong? You know, I haven't seen any new episodes of that in a while. Yeah, you had to have kids in the right period, folks, but

there's a series of books. Oh, wait, wait, no. Yours was three-dimensional. I think we're okay. Oh, good. All right. And not animated. All right. Next week, we have a superb prize for people. Tell us, what's the question first?

The question is, speaking of moon sizes in the solar system, natural satellites, what is the only moon in the solar system that is between 2,000 and 3,000 kilometers in diameter? Just kind of hanging out in a size gap. Only at, there are ones larger and smaller, but only one. Between 2,000 and 3,000 kilometers in diameter, tell us what it is. Go to planetary.org slash radio, find out how to enter. And you have until the 17th, that'd be Monday, October 17th at 2 p.m. Pacific time. Here's the prize.

We mentioned it last week when we were talking to our guests, John Raymer and Don Dixon, the space artists. It is a paperback copy of The Beauty of Space, space art from the International Association of Astronomical Artists, and there's work by over 100 artists in here, and I think about 11 of these works are signed by the artists. That's cool. Yeah, isn't it? And it's a beautiful book. Absolutely beautiful. You can go to the association's website, find out how to buy one, but heck, you might win it. That's cool. the last 25 minutes or so last night of Aliens 3. I did not even know this.

Oh, gosh, talking cheesy. Sigourney, I hope you were really well paid. He's Bruce Betts, the director of projects for the Planetary Society. He joins us every week here for What's Up. Next week, bringing an asteroid to Earth on purpose. Planetary Radio is produced by the Planetary Society in Pasadena, California and made possible by a grant from the Kenneth T. and Eileen L. Norris Foundation and by the members of the Planetary Society. Clear skies. Thank you.