Planetary Radio: Space Exploration, Astronomy and Science - Look Out! It's a Martian Avalanche!

Episode Date: March 17, 2008

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Look out! An avalanche on Mars, this week on Planetary Radio. Welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. Alfred McEwan is in charge of the most amazing camera ever to visit Mars. He will tell us about his eye on the Martian sky and what remains for it to accomplish. Then we've got another special report from Emily Lakdawalla.

She attended the just completed Lunar and Planetary Science Conference in Texas. We'll finish as we always do by allowing Bruce Betts to award one of you a Planetary Radio t-shirt, even as he tells us about a night sky that is lousy with planets. Almost no time for headlines in this jam-packed show. Cassini survived its close encounter with Saturn's moon Enceladus. We're waiting for its analysis of the vaporous plumes it flew right through.

There's a report that 20 to 60 percent of our galaxy's stars may have rocky planets circling them, and Space Shuttle Endeavour's crew is hard at work at the International Space Station. There's more at planetary.org. Time for Bill Nye the Science Guy, who has an invitation for you this week. I'll be right back with Alfred McEwen. Hey, hey, Bill Nye, the planetary guy here and vice president of the Planetary Society. I'll also be moderator of a forum that the Planetary Society is sponsoring about outer space exploration policy. And this forum will take place in Brookline, Massachusetts, not too far from Boston, the same weekend as the National Science Teachers Association.

That is the 29th of March, Saturday, 4.30 in the afternoon at the famous Clay Center. Whoever wants to come, we'll sit around and talk about the policy that we need to explore space. You know, I often talk about the discoveries in space. But now we're going to talk about how we go about getting there, our government policy, and what we can do to influence governments around the world to, how to say, explore space the way we think best. We'll talk about the space shuttle. We'll talk about the vision for space exploration. We'll talk about the European Space Agency's plans. We'll talk about whatever you want, and I will do my best to keep the discussion under control. I will moderate it. I mean, people, we've got rings around a moon

of Saturn, which in turn has rings. We have an avalanche on Mars. We've got more rocky planets than gas ones. We've got things going on in the cosmos that will astonish current and future generations. And, of course, we have exploration of our own planet. We have Earth science to discuss and how space policy should figure into that. So come on out to the Clay Center, and we will have, I hope, a lively and, what's the modern word, substantive, substantive discussion of space policy. Bill Nye, the space policy guy here, talk to you soon on Planetary Radio. There have been a lot of cameras on and near Mars,

but none compare with HiRISE, the High Resolution Imaging Science Experiment. Alfred McEwen leads the HiRISE team from the Lunar and Planetary Lab at the University of Arizona. We've wanted to talk with him for ages, but when his camera captured a Martian avalanche, we just couldn't wait any longer. I look at the images from this instrument, and I am just flabbergasted. Some of them almost bring tears to my eyes. They are so beautiful. I think they are as pretty or prettier than most of the images I have seen of this planet from space.

And we've got a pretty nice-looking planet. Well, I agree with you about the images. They bring tears to my eyes, too, and the credit goes to a lot of engineers and others who process the images here and so forth, and I'm lucky enough to be a part of this. Let's talk about that avalanche picture, which is sort of the inspiration for this conversation happening while it does. And then more generally, we'll talk about this pretty amazing telescope, this eye in the sky that you've got circling Mars.

Were you surprised by the huge media reaction to this sort of live shot of an avalanche in progress? Well, I guess not, because this was actually acquired or noticed, at least, when I was off at the MEPAG, Mars Exploration Program Analysis Group, meeting off in Monrovia. And so it was the operations staff here who discovered it and commented on it, and they generated like 50, 100 emails on this, so they were excited. And so that made it clear that others would be too. And it's great to see something in the act, active Mars. And really, it is that dynamism, quite literally, of this photo. I mean, looking at the fact that this is anything but a dead planet.

Yes, and we're still trying to understand what exactly we are seeing here. For example, are there blocks of ice that have tumbled down the hill, or is it more fine-grained material? And what role did wind play in this? What role did temperatures play? This is actually a very unusual place on Mars. This is a very steep slope. In the polar layer deposit, it's up to a 60-degree slope, and it faces south.

So we're at the time of year where it is getting sunlight as if it is on the equator, that slope. So this is ice that's getting a whole lot of sunlight right now. So we should have predicted that this would be an interesting place at this time of year. When you mention ice, are we talking about dry ice, carbon dioxide, or some water ice? The layer deposits in the North Pole are mostly water ice, but there is seasonal CO2 that is rapidly sublimating here in this season. And on a steep slope like this, that sublimation could well destabilize the dust that gets trapped with the CO2 ice. So how similar is this activity to, as far as we know, to an avalanche on Earth? Well, it's material flowing downhill under the influence of gravity,

similar to a snow avalanche. Probably, though, this is mostly dust. There may be even some larger blocks, more like a block fall, blocks of ice, in this case water ice. So that's very, very analogous to processes that happen on Earth. I'm also thinking of some of the other images that you've delivered. I know there are some we talked about on this show not too long ago of craters, newly formed craters where HiRISE was able to look at the same spot on Mars over a period of time,

and you saw that, yeah, this place is still getting hit by rocks. Yeah, well, this was a discovery from the Mars Global Surveyor mock camera, and we're following up on that. We've re-imaged all of those craters to get better measurements and counts of all the small craters associated with them. And we're finding new ones. That's both the context experiment camera on MRO and HiRISE. MRO is a very well-endowed spacecraft,

and it's really nice to have both this Context camera, which is 6 meters per pixel, 30-kilometer swath. So they can cover substantial areas with repeat coverage. Then when they find something interesting, we can follow up on it with HiRISE for higher resolution, and the CRISM spectrometer can follow up to get compositional information and so forth. So this is a really great mission for finding and characterizing active processes. It is a great spacecraft, and I guess, really, HiRISE's great strength

would also be a huge limitation without other instruments like the Context camera. I mean, really, your field of view is pretty small. Yes, it's about a degree, and that's about six kilometers on the surface of Mars. So, yep, that's pretty small. You've got up at the website from the Lunar and Planetary Lab there at the University of Arizona, there are a number of interesting pieces, one by you talking about additional evidence for water on Mars. It leads with another absolutely gorgeous photo of channels, gullies on the planet. The arguments, of course, about whether this stuff has actually been created by water and

whether that water was maybe in liquid form goes on. Where do you stand with all that? Well, at this point in time, the science community knows that Mars is a water-ice-rich planet. There is ice in the polar caps on the surface. There's ice in the shallow subsurface as mapped by the gamma-ray spectrometer and that the Phoenix mission is going to go dig into. And there's abundant evidence for ice in the deeper subsurface at lower latitudes from viscous flow features, relaxed craters, the gullies, and fluvial features we see in association with large impact craters.

So there is ice in the crust of Mars. And Mars has been cold most of its history, cold enough to keep that water frozen. But there is evidence for water on the surface at times. It may have been brief times and at various times throughout Mars history. So the answer is yes to all of the above. It's usually wet in terms of H2O in frozen form, but it's usually frozen. There are brief times in which it melts. Probably in the subsurface, if you go deep enough,

there is groundwater that stays consistently liquid. And so we're getting down to the details now of understanding when and where and how did the water reach the surface. More from High-Rise Principal Investigator Alfred McEwen in a minute. 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, And I hope you'll consider joining us. 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're continuing our conversation with Alfred McEwen, principal investigator for the high-rise camera circling the red planet on the Mars Reconnaissance Orbiter. We have discovered so much about this planet in just the last decade or so. Because of wonderful instruments and terrific spacecraft like MRO, instruments like HiRISE, does it surprise you sometimes that we've been able to uncover so much knowledge about this planet that hid so much from us for a long time?

It's amazing what a success the Mars exploration program is. I started my career in the 80s when we were in this great drought. Viking had finished, Voyager was continuing and having an encounter now and then, but it wasn't until the late 80s that we launched several new spacecraft, including the first Mars mission since Viking, Mars Observer, although that one failed. Following that, though, were a series of Mars missions that have been successes, and it's been amazing. We have so much data on Mars, both from orbit and from the ground, and it's a very diverse planet, so we're still learning, but it's really great to have all this data. Back to HiRISE, why do you and your team like to call it the people's camera?

This was a concept we had for trying to do things the right way. I mean, this is the taxpayers paying for this, and we want to optimize the science return and the public interest in HiRISE, and we do that in a couple of different ways. One is by, that we've done well up to now, is by processing and releasing the images quickly so that everyone can enjoy them with us and provide tools to make it easier for people to browse over these. These are enormous-sized images, and it frees up your computer if you try to download the whole thing. So we have special tools that people can browse these.

The other part of this that we haven't done as well as we'd like is to get public input on targeting. And we've had some quest challenges, which are a special EPO event where this has been done. But as far as opening up our whole targeting system, we've had some snafus there with security and so forth, and we're still trying to do that, but we haven't quite gotten there yet. But that's why we call it the People's Camera, because we're, to the best of our ability, making this an open experiment and inviting everyone to participate. You know,

it's only occurred to me as we've been talking, otherwise I'd have looked it up on Amazon, but has anyone considered putting out a coffee table book of high-rise images? Yeah, I have. I just can't find the time to actually follow through on it, but yeah, I'd love to do that. It can be difficult to make money off of that type of thing, and so the publishers may be somewhat reluctant. type of thing, and so the publishers may be somewhat reluctant. Also, what we really need is a really big coffee table to do justice to these images, but we can cut out features of interest, obviously, and that would be a great thing to do, and I hope to do it. Where do we go from here?

MRO, HiRISE, and perhaps even beyond. Can you even imagine an imaging device in orbit around Mars that would perform better? And really, would we need something that would perform better than HiRISE? Well, I can certainly imagine it, and it can be done. We have the technology for spy satellites around Earth, and we know how to do it, but it gets more expensive as you go to higher resolution. There is science value in that for sure. I mean, look at all the things you can see from the ground, from the rovers, that we still can't resolve.

But if you have it in orbit, then you're not restricted to a couple of small places. You could look anywhere on the planet. That's probably not going to happen anytime soon. In fact, the whole future Mars program is kind of in disarray right now where future missions are being delayed or canceled and the budget's being cut. And it's almost like we're being punished for being so successful. So it's hard to say what's going to happen. But there is coming up the Mars Science Laboratory, assuming they can get

finished and launch. And that will be spectacular and provide very high-resolution observations and in-situ measurements as well. So there's still lots of good stuff to come. And how about MRO and HiRISE in particular, since that's your concern? Yeah, MRO has lots of fuel. We can stay in this low orbit for a dozen years easily. All the instruments are working well. All of the major spacecraft systems are working well with some issues in some places, loss of redundancy. So there are always areas of concern. But overall, the health of MRO is excellent. And we're in the process of negotiating what to do in the extended science phases. And we hope that NASA agrees that we should keep going in collecting data. What on Mars do you most want to still take a look at or continue to observe?

There's so many things on Mars, it's hard to know where to begin. It is a whole planet. But certainly dynamic processes, continuing to monitor the active craters, the active slope movements, look for any slope movements or deposits that might be associated with water. Polar processes such as the avalanches and the frost and dune migration. And the longer the time period we have, that time combined with high resolution means we

can measure the rates of processes. That gets us into a different area of science that's more quantitative and there's a lot of uncertainty about the ages and rates of processes on Mars. That's one area. Another area is in the ancient crust of Mars where the spectrometers have discovered clay minerals and other aqueous minerals, and HiRISE is showing bedrock layers with layering or polygonal patterns, and all of this is very interesting. We have a lot of work to do combining HiRISrise and CRISM and other data sets to really understand

this, but we know we're going to want to cover more terrain as well. Well, please keep up the great work and please keep sending those wonderful snapshots home. Hard to call those things that are so huge snapshots. We will also leave our listeners with a link to your website there at the Lunar and Planetary Lab, which is a wonderful place not only to see these stunning images,

but also to read about the science that they are delivering and what they are telling us about the red planet. Alfred, thanks very much for joining us. Thank you. Alfred McEwen is a professor at the University of Arizona in geosciences and planetary sciences at the Lunar and Planetary Lab, but he is also the principal investigator for HiRISE, the High Resolution Imaging Science Experiment, or the People's Camera. We're going to continue Planetary Radio in just a moment with our version of, well, the people's mouth, you might say. Bruce Betts will be here with What's Up.

That'll be right after our weekly visit with Emily. Emily, welcome back. When we talked to you last time, you were in Texas, and you were about to go off to the LPSC, the Lunar and Planetary Science Conference. Did I get that right? You did. So was there a particular standout? Well, the most anticipated session and the reason I went down there on Monday was probably the first results from the messenger flyby of Mercury. For those sessions, the meeting hall was totally packed. I have to say there

wasn't any real earth shattering news to report. And I think the reason for that is because Mercury is just really, really challenging. It's a whole world. It's bigger than the moon. It's nearly as big as Mars. But we don't know a whole lot about it. And the messenger data is just showing us how complicated the story is. There is one presentation where they showed craters that were filled with lava. And then the crater got faulted.

And then it got filled in by more lava. And then it got cratered again. So you've got volcanism and cratering and tectonics, and all of these things were happening at the same time. It took hundreds of millions of years to play out, and it's going to be hard to unravel the story. But the data from all of MESSENGER's instruments is just gorgeous, and by the end of the orbital mission, they should have made a lot of progress on figuring out the story. So lots to look forward to from Mercury. Any other highlights at the conference? Well, I have to say that the major highlight for the whole conference is just to observe the fact that the moon is suddenly in vogue again. For years, the Lunar and Planetary

Science Conference, which after all is named after the moon, it's been kind of lean on lunar topics. But this time, if you look at the schedule, there are presentations on lunar science happening all week long, continuously, all five days. I think this is because of current and recent missions to the moon, like Japan's Kaguya and ESA's SMART-1. But it's also because NASA is now making new investment in research and analysis about lunar data, looking forward to the, you know, moon to Mars initiative. Any other surprises? Well, I thought one of the neat things at this conference was a few presentations by some, what you might think of as outsiders, people who aren't on NASA grants and aren't even planetary scientists.

One was an English professor named Ted Strick who took a second look at some data from the Voyager flyby of Uranus, which happened in 1986, and he used special processing techniques to reveal features on the night sides of Uranus's moons. And he could see these features because of light reflected off of Uranus and onto the night sides of the moons. That's amazing. 32-year-old data. There was another paper from, well, I guess you'd call him an outsider, who I guess came

up with a new way to make maps. He did. This is a Georgia architect named Chuck Clark who devised a new way of making maps of very strangely shaped bodies. And you can actually cut out and fold his maps into pretty good facsimiles of the odd shapes of these things. I did his map of Phobos in the blog, and he gave me a Deimos one that I hope to post this week. Tab A into slot B and that kind of stuff, it sounds like. into slot B and that kind of stuff, it sounds like. Let's talk a little bit for a second, bringing it home, to sort of the mood among particularly people in the Mars community, because there has been a fair amount of concern lately about

changes in Mars policy. And a lot of these folks have not been real happy. Yeah, the mood among the Mars scientists at LPSC, it was concerned more than angry, I think, because there are clear problems with the Mars program. There's a question of where do you go from here? There are missions that are overrunning their budget by huge amounts, and that's putting a lot of pressure on future Mars exploration. Headquarters is really pushing for Mars sample return, which a lot of Mars scientists really want, but it's going to be a very expensive, very complicated mission. And you may find that the Mars science community has to put all their eggs in one basket for Mars

sample return and not have a very good program of landed and orbital missions going out the next couple of decades. So people are kind of worried and really not sure where to go from here. Well, limited resources, I guess, mean limited science. Emily, we will simply, as always, suggest that people go to the blog if they'd like to hear more about your observations and things you heard from the LPSC. Thanks again for giving us an update. You're welcome. Emily Laktawalla is the Science and Technology Coordinator for the Planetary Society, and of course, she is also the originator of the blog at planetary.org, which is where you can read much more. Back in just a second with Bruce Betts in this week's edition of What's Up. Wow, no sooner has Emily left, but Bruce Betts enters the Skype virtual studio.

He is the director of projects for the Planetary Society, and he's back for What's Up. Going to tell us about the night sky and other cool stuff. Had my heart set on getting together in person this week, but I guess it was not to be, so maybe next time. We must move on. Let's move into the night sky, shall we? In the evening sky, you can check out Mars high overhead, kind of towards the west. In the early evening, it is the orangish-reddish object. It keeps getting dimmer and dimmer as we get farther and farther away,

but still looking like a fairly bright star. Up above Orion is how I like to think about it in terms of finding it. And then Saturn is up and in Leo right now. And Saturn is up high overhead again in the early evening, but farther, farther towards the east compared to Mars, they will actually grow closer over the coming weeks and months. So, so look for that. And you can check out Saturn always with a small telescope and check out those rings if you never have or even if you have. It's a nice time to look at them. And we've got in the pre-dawn sky Jupiter, the brightest star-like object over there that's easy to see.

But Venus, you still might catch low down towards the horizon to Jupiter's lower left. Venus is even brighter, so if you see two bright star-like objects, Venus is the brighter one. And Mercury, you might catch to the lower left of Venus, looking like a bright star, but not bright compared to the other two, and extremely low on the horizon, so you want to look right before dawn. And that's our planetary lineup this week. You been out observing recently, Matt? No, no. There were even decent skies down in San Diego night before last. All I did was look up and wish that I had a telescope or binoculars. But you did the look up and ponder your place in the universe? Always. Always. Good. On to

Random Space Fact! Milky Way. I am so craving some chocolate right now. But instead, I'm going to talk about the galaxy. Milky Way galaxy, it is 100,000 light years across, but only in terms of the stars in it, only about 1,000 light years thick. That is one thin candy bar, but really, really big. And it's also, if you count the gas, it's much thicker. And of course, it's thicker near the galactic bulge. About 200 to 400 billion stars in the

Milky Way galaxy. And where's our place in it? Well, we'll come back to that in just a moment. First, let's go on to the previous trivia contest. We asked you, what is the largest of Uranus's moons? How'd we do? Lots of responses. Thank you, everybody. I'm going to go right ahead and tell you our winner, if that's okay. Oh, please do. Leap right into it. I will. Craig Markley, Craig Markley of Savannah, Georgia, first-time winner, who did indeed come up with Titania. Titania at about 1,578 kilometers in diameter, discovered by our good friend Billy Herschel in 1787. Titania.

Now, I've always heard Titania in the planetary community. Now, it is derived on Shakespeare Shakespeare and you're wiser in such things. Should it be Titania? Well, I have a daughter who actually played one of Titania's servants in Midsummer Night's Dream and I'm pretty sure they said Titania. You know this goes back to the old argument

about Uranus itself that has caused junior high snickers for gosh, centuries. Really? You didn't know. I've never heard that. Never has that come up in any of my talking to kids. I'll explain when we're done.

All right. Well, Titania, Titania, let's call the whole thing off. Back to the Milky Way. Let's give someone else a chance to win a Planetary Radio T-shirt, as we've just given away. Answer the following question, which is, how far away are we from the galactic center of the Milky Way? How far away are we from the galactic center of the Milky Way? And I'd go with light years, since we're pretty darn far away.

Yeah, please don't give it to us in ping pong balls, folks. We love those units, but stick with light years this time, and then if you want to get creative, go beyond light years. And next time around, next distance question, we'll come back on the solar system, but this one, a pretty darn big number. Distance to the galactic center.

I can tell you that we rotate around the center every 220 million years, if that makes it easier for any of you. I'm getting ready to celebrate Galactic Rotation Day. How many of those have you seen now? Three or four. Oh, okay. I guess that'd be more of a revolution than a rotation.

You're right, you're right. Go to planetary.org slash radio, find out how to enter, and try to win that Planetary Radio t-shirt. And be sure to get us that entry by the 24th of March, just past the Ides, the 24th of March, 2 p.m. on Monday, 2 p.m. Pacific time. All right, everybody, go out there, look up at the night sky, and think about condensation.

Thank you, and good night. I'm still thinking rotation revolution. You know, I've been doing that my entire life. Revolution, revolution. He's Bruce Betts, the director of projects for the Planetary Society, and he joins us right here every week with What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Thank you.