Planetary Radio: Space Exploration, Astronomy and Science - Martian Ice is Everywhere...Almost

Episode Date: December 8, 2008

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More water, and lots of it, on Mars, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Water, water everywhere? Maybe. We'll talk with Jack Holt of the team that says it has discovered massive Martian glaciers far from the Red Planet's poles. Speaking of Mars, Bill Nye, the science and planetary guy, has some thoughts about the just-announced two-year delay in the launch of the Mars Science Laboratory. We'll hear from him in a few seconds.

Why haven't we seen the actual flotsam and jetsam that makes up Saturn's rings? That sounds like a good question for Emily Lakawala's Q&A. And stay tuned to hear what the Little Prince and Bruce Betts have in common as we learn about the current night sky and give away another Planetary Radio t-shirt. More news is waiting for you at planetary.org. Here's Bill. Hey, hey, Bill Nye the Planetary Guy here, Vice President of the Planetary Society. And the news this week is the Mars Science Laboratory, formerly the Mars Smart Lander, same acronym, MSL, has been postponed. Now, when you postpone a trip to Mars, you don't

postpone it a few weeks. No, you got to postpone it 26 months because that's the next orbital opportunity for the rocket to get on its way to Mars inexpensively or reasonably pricely. The thing is, everybody was hustling to make this lander be something special, something else. I mean, the thing is 10 times the size of Spirit or Opportunity, the Mars Exploration Rovers, which are still working up there. Their fifth anniversary is coming up. It's like the size of a Mini Cooper, and it has 10 elegant instruments on board. Now, here's the thing. The price has gone up because there have been some problems.

There have been some problems with the actuators. There have been some problems with the testing and the schedule for the testing. So the price is going to go from only $1.6 billion to $2.3 billion or maybe $2.2 billion. That sounds like a huge amount of money. And I guess it is. But the thing is, if you divide that over the number of years that the program's been going, it's almost 10 since the turn of the most recent century, and pick a number, 300 million of us taxpayers, that's barely $6. Over 11 years, that's like 50 cents a person to make a discovery on Mars that we really literally can only imagine right now. Just think if we could get this rover near those glaciers in two years and drive around. Oh, my friends, we might make discoveries that will, dare I say it, change the world.

You know how I love to talk about Mars. Well, this is another Mars piece of news. We're delaying the launch of the Mars Science Laboratory in order to make sure that it's tested well. See, the reason Spirit and Opportunity are still going after five years is they were so well tested. Thanks for You heard it from Bill last week on this program. Researchers have discovered water ice on Mars. Okay, so that's not news. But where they've found these new deposits and how much ice they've found is big news indeed. Some of it may be up to a half mile or nearly a

kilometer thick, shielded from the harsh surface by a layer of dust, gravel, and rock in the Hellas Basin region of the Southern Hemisphere. Jack Holt is the lead author of the paper published in Science barely two weeks ago. He's a research scientist in the Institute for Geophysics at the University of Texas, Austin. Jack joins us from his office where he is preparing for a trip to Antarctica. Jack, we are really thrilled to have you on the show today, and congratulations. How much ice, how much water ice are we talking about? Have you and your team discovered on Mars?

Well, Matt, we're talking about a large amount of water that's yet to be determined, but based on some assumptions about what is there using altimetry from Mars orbiting laser altimeter and making some assumptions about how the bottom of these things is shaped, it's looking like globally we could be talking about as much as 10% of what's in the polar caps, which is quite a bit larger fraction than is found in nonpolar glaciers on Earth, which is about as less than 1% of the polar caps on Earth.

Wow. That's a lot of water. It makes me think of, I don't know if you're familiar with the Kim Stanley Robinson series of books, Red Mars, Green Mars, Blue Mars. I am. It's been a long time since I've read any of them, but I'm tempted to pick them up again. Well, when I read them and he started talking about this kind of ice hidden away on Mars, I thought, he's crazy. This is a fairy tale. Maybe not. Yeah, that's right. A lot of people have brought up Total Recall, too.

Yeah, that's right. And even sent me pictures from the movie and said I should have credited Arnold for some of my motivation. Yeah, well, if you can find those big Martian machines that are going to release all the oxygen, we'll get instant terraforming. Yeah. We'll have it made. I think so.

That would definitely be in the right direction. Yes, I think in addition to what we found in these deposits, which have been hypothesized to have a lot of ice in them, but nobody knew and had a way of knowing until now. I think what really is exciting, too, is that this shows that you can preserve massive amounts of ice at latitudes where there shouldn't be ice today with just a thin layer of covering on top. And it can last for millions and millions of years, probably hundreds of millions of years in the case of these deposits. I'm glad you brought that up, because I wondered about that. I thought, you know, we're talking about that kind of time span. I'd have thought that this

stuff would have sublimated away, even though it's got that nice coating of dirt. Right. Most people thought that it would take a lot more dirt on top to protect it, but apparently not much. And even in the case of Phoenix, you know, they just scrape away a few centimeters and they find ice underneath that. So I think what we're seeing is there could be ice just about anywhere on Mars underneath a little bit of surface dust and dirt. It may be deeper at the equator than at the mid-latitudes, but we keep being surprised by how much there is and how close it is to the surface. So I think that's really exciting.

We could go to lots of places on Mars, maybe down in craters and find little reservoirs of ice tucked away. For those who may not have heard all the details of the story, tell us how you used this Italian radar system on the Mars Reconnaissance Orbiter to peer through that layer of rocky debris. Sure. It's pretty straightforward, really. In some ways, it's like using a police radar gun, for example, to bounce radar energy off of something.

And in this case, though, we're at a much lower frequency, which is a longer wavelength, that is able to penetrate through certain materials. When it bounces off the surface, some of that energy is able to transmit through the ground. And then if there's a boundary that has an electrical contrast and electrical properties, you can get a return signal that bounces off of that lower interface and then comes back through the material again, back through the surface. Each time you go through an interface, you lose energy, but the radar is very, very sensitive, so you can detect a very weak reflection.

That's basically it. It's perfect for going through ice. It's been used for many decades on Earth to study glaciers and the polar ice sheets on Earth. These kinds of targets, like these Lees-Lobate aprons, are more challenging than polar caps, but it just works beautifully. You know, Bill Nye in his commentary last week on this show joked about how we need to set up a Martian backhoe. But have you been able to tell how much of this protective debris we'd have to dig down through to reach the ice? Well, about the best we can say right now is that it's approximately within the resolution limits of the radar. The drawback to being able to penetrate through the surface is a loss in vertical resolution. This radar was designed to look in the upper several hundred

meters of the surface and maybe up to a kilometer, the balance was about a 10-meter vertical resolution. So we don't see a lower boundary to that dirt layer on top, which means either one of two things. Either it's a very gradual transition from rock or dirt to ice, or it's a very thin layer. It's less than or approximately equal to the resolution of the radar. So given what we know about these kinds of deposits that look similar on Earth, I expect that it's a sharp transition, and we're looking at something that's just a few meters thick, probably. That's exciting. And Is it possible that in some areas it's thinner than others? That seems logical. I think so.

It's very hard to say at this point, and we may not be able to tell with the radar, this radar anyway, if it's, you know, 1 meter versus 10 meters. If it were 100 meters, I think we would see a reflection off the bottom. So as we look at more of these, I think we'll get a sense for how consistent that is. Others are looking into high-resolution imagery and high-resolution morphology, and especially where there's impact craters. And they can model how these things should deform and come up with some constraints on the thickness of that top layer as well because the materials behave differently. That's research scientist Jack Holt

of the team that has discovered glaciers on Mars. He'll be back in a minute with word of even more ice. This is Planetary Radio. Hey, hey, Bill Nye the science guy here. I hope you're enjoying Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era. Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J, the passion, beauty, and joy of space exploration.

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We're celebrating the discovery of massive glaciers on Mars, revealed to us by an Italian-made radar instrument on the Mars Reconnaissance Orbiter. Radar was necessary because the water ice is hidden under and protected by a layer of rocky debris. Jack Holt is a research scientist at the University of Texas, Austin, and the lead author of the paper that announced this find, made by an international team. Your team's work is already out with you as the lead author. You were looking in the southern hemisphere. I just read that another group of researchers is about to publish some similar results farther north. I think I know what you're referring to.

It's basically the same group. We just rearranged the author order. I see. Because since Mars is big and our team is fairly small, we were looking at different places at the same time. Basically, one of us came up with this finding in the southern hemisphere and another in the northern hemisphere. But we were really working together on both of these, applying the same techniques. These particular types of targets are challenging in the processing sense and the analysis sense. So we had to develop the same kind of tools and apply them to both places. You've already referred to this, as have most people, but to be able to find these deposits of ice so far from the poles, I mean, as Bill Nye said, we're talking just about in the tropics here,

really does seem to be very encouraging and very surprising. It does, and I think it bodes well for future exploration of Mars. If we can ever get to the point where we can send people and establish bases, it opens up the door to supporting a large or even a small colony or, I don't want to say colony really, but a base for further exploration because you've got this massive resource of water right there. Where does your team go from here? How do you continue this work? Well, the next step is really to acquire as much data as we can over as many of these kinds of

deposits and everywhere we can, basically on Mars that looks like a possible reservoir of water ice. We can't operate the instrument continuously as MRO flies around the planet because it just takes too much data. We can't send all that back. So every week we have to set priorities for observation. Since these features are relatively small, just a few tens of kilometers across in many cases. You have to take advantage of when the spacecraft is actually right over it and then designate that as a target, get that in the queue, and try to make it happen. So at the moment, while the spacecraft is still operating, I just want to take as much data as we can over these things. The irony there is great.

I like to think of some of the earliest Mars probes, like Bruce Murray sent up from JPL, and the dribble of bits they got back, and now your limitation is too much data. I know. It is really amazing. And this spacecraft, you know, MRO is sending back more data than all other space missions combined. The radar often just takes the data on the night side of the planet because the other instruments can't operate, take pictures at night. You are just a few days away from a trip down to McMurdo Sound to Antarctica. Is that related to this direction that your research,

that your personal interests have gone? It certainly is. And it's how I got into this place looking at the Mars data to begin with. My group here at Texas has been doing airborne radar sounding in Antarctica for 15 years. Since I joined the group about 10 years ago, I started getting interested in targeting some features in the dry valleys of Antarctica, which is considered to be one of the best Mars analogs on Earth. There are features there that look like these glaciers on Mars. They're covered with a layer of rock. There's massive ice underneath, and they've been studied for a long time. They could contain the oldest ice on Earth.

This year, when we go back, I'm flying a new radar that will attempt to emulate the radar on MRO by having the same frequency and the same bandwidth. And if we can study these features in Antarctica with the radar where people are doing ground studies and can evaluate composition, thicknesses of layers, things like that, then I think we'll learn a lot more about what's on Mars. Does that mean, in a sense, you'll be able to better calibrate your data from Mars? That's correct, yes, because there's always some uncertainties, and the more data you have, the better off you are. But airborne and orbital radar data is a tool that's fairly new in the planetary sense

in terms of studying other planets. So the more we can do to understand what impacts the data, the better we will be. Jack, just one more question. You're a geologist, of course, but I wonder, have you had any biologists, including exobiologists, coming up and patting you on the back and saying, boy, you've given us some more things to wonder about up there on the red planet? Well, not yet, but I hope it'll happen. I talked to one friend from graduate school who's in astrobiology, and he did say, well, you know, this really is quite a surprise. There's a lot more water ice than we think, and we have to think about the timing of it,

but it is a window into the past. You could learn something about the atmosphere on Mars at the time these deposits were formed, you know, 100 to 200 million years ago, most likely. So that's another avenue for learning about Mars climate history. Well, with two more years now to work on it, maybe we get that backhoe attached to the Mars Science Laboratory. I think that's a great idea. If they could just, yeah, attach a backhoe and park next to one of these

and dig down and see that ice with our own eyes, and maybe they could clear out enough rocks to make a ski run. Yeah, we'll send up a Zamboni next, I think. Jack, from your mouth to NASA's ears, and congratulations once again to you and this entire team with this radar instrument on the Mars Reconnaissance Orbiter for the discovery of these massive amounts of water ice on Mars. Well, thanks to you for letting me be on the show, and it's really, really great fun to me. It's some of the most fun I've had doing any kind of science. And I have to give credit to all the people who studied these features with optical imagery and laser altimetry data in the past and set the stage for us to come in with the radar data

and probe the subsurface and be able to say what's there. Thanks, Jack. Well said. Jack Holt is a research scientist at the Institute for Geophysics, the Jackson School of Geosciences, at the University of Texas at Austin. He's also the lead author of this paper just published a couple of weeks ago that talks about this discovery of, what more can we say, glaciers, massive amounts of water ice hidden away not very far under the surface of Mars. Well, we're going to unveil things in the night sky as we visit with Bruce Betts for

this week's edition of What's Up. That'll be right after our weekly visit with Emily Lakdawalla for Q&A. Hi, I'm Emily Lakdawalla with questions and answers. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, Cassini has a unique opportunity to actually observe up close the objects that make up Saturn's rings, but we haven't seen any pictures like that. Will Cassini ever get close enough to the rings

to see individual objects within them? Saturn's rings are made up of countless objects that vary in size from grains of dust to boulders more than 10 meters across. There's two ways we've deduced the sizes of ring particles. The first is from how they appear from a distance. Parts of the rings that are made of fine dust are transparent and are brightest when the

Sun is behind them, while parts of the rings that are made of bigger bits are more opaque. The second is from the way they block or scatter radio waves broadcast by spacecraft as they pass behind the rings. But we've never gotten a picture of what the bodies in the rings look like. The highest resolution images Cassini has ever taken came from a close flyby of Enceladus, when it barely resolved boulders on the surface about 20 meters in diameter, or about the maximum size of bodies in the rings, Cassini would have to get even closer,

within a few kilometers, of the rings in order to see their particles well. But there's no way Cassini will ever be able to get that close. Cassini can't just swoop in for a close view and then rise back up like an airplane or a balloon. It's always on an elliptical orbit around the center of Saturn. So to get that close to the rings, it'd also have to be just about to cross the ring plane, which would certainly mean smacking into the rings and ending the life of the spacecraft. Seeing the objects in the rings is an event that's going to have to wait for us to develop real space ships that we can steer and fly where we choose.

Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. We're out back, ready to talk to the Director of Projects for the Planetary Society, Dr. Bruce Betts. He's here to tell us about the night sky. And let me tell you, I got to see a piece of the night sky a few days ago. You were right. The moon, Venus, and Jupiter, they were lovely.

Wow. Can you say that again? They were lovely. No, no, no. Before that, the part about you were right. Oh, you were right. Okay. Just checking. Cool. Cool. Yes, the part about you were right. Oh, you were right. Okay. Just checking.

Cool. Yes, they were quite lovely in there. They're spiffy triangle. The good news is you can still check out Jupiter and Venus for the next, at least through the end of December or so. Then Jupiter is going to get a little low. Venus is actually getting up higher. So look over in the west if you haven't already or even if you have. After sunset, they're the two really bright star-like objects.

Venus is the brighter of the two, and will be getting higher as Jupiter gets lower over the coming weeks. Cool, huh? Hey, the Geminids, the traditional best meteor shower of the year, are peaking on December 13th. They can go, on average, 60 meteors an hour or even more from a dark site. But here's the bad news. It's right around full moon. So you'll still see the bright ones, but it's going to wash out some of the dimmer ones. We'll have a harder to produce group of meteors early in January, I'll tell you about later. Okay. So that's our basic night sky. Let's go on to... So that's our basic night sky.

Let's go on to... Random Space Fact! Wasn't that for Halloween? It's kind of frightening. Why, thank you. I'm scared. Had a little left over. Oh, I'm really bothered now. Okay.

Okay, good. The Messier objects. They terrify me. Okay. Okay, good. The Messier objects, they terrify me. No, they don't. The Messier objects and the messy, messy objects that all amateur astronomers are quite familiar with. Let's get all of you familiar with them. There are over 100 objects. They get cute little numbers. M1, M10, M31.

M31. M31. Big31. M31. Big favorite of mine. Big galaxy dude. But it's kind of interesting why Charles Messier started making this list. It's because he was a comet hunter, and he kept getting annoyed that he'd lose track of these fuzzy objects because, you know, that's pretty much what they all are in a small scope is one kind of fuzzy object or another. Get him confused with comets, so he started making a list of them.

And you ended up with the Messier catalog to 300 years ago, and it's continued on to this day, and people, good astro nerds like you, just refer to things like M31. You sunk my battleship. Yeah, well, it's like this. M31, probably the only one that I actually know. I was just trying to sound cool. Oh, you too.

Yeah. You do. You'll know more soon. Ooh, foreshadowing. But first, let's go on to our previous trivia contest where we asked you a question that's hard to phrase. The first person who was born to two people who had both flown in space. Tell us that person and the two parents who had flown in space. How did we do, Matt? We got it.

Now, a number of people came up with great answers but not the right answers. For instance, Craig Hutchinson talked about Julie Gibson, who's the eldest child of Robert Lee Gibson and Margaret Rhea Seddon, both of whom were on the space shuttle. But it actually happened long before the space shuttle. And I think you know at least who Mom was because Mom was pretty famous. I mean, the first woman in space, right? Yes, she was indeed.

Valentina Tereshkova. Yeah, who was apparently really was plucked off the factory floor, although she was a parachutist, I guess. Went military after she flew into space and became a general and so on and so forth. And she hooked up with Andrey Nikolaev, who has passed away. From them spewed forth... A spawn of space? A space seed, yeah. Elena Andriyanovna. Elena Andriyanovna,

born in 1964, June 8, 1964, to be exact. We got that from a lot of people, but the winner is Richard Garcia, who is an aerospace engineering undergrad not far from here, Cal Poly Pomona, part of the CSU system. We're going to congratulate Richard and send him a T-shirt. Congratulations. Good job. Let's give people another opportunity to win a T-shirt.

There was a famous supernova in 1054 observed by various people, including Chinese astronomers. Suddenly, a bright star that wasn't there before, it left a remnant, a nebula. So, this week's trivia question. Tell me what the name of that nebula is that was left over from the 1054 supernova. And tell me its Messier number. Go to planetary.org slash radio. Find out how to enter. So the common English name and the M whatever number. Exactly.

Okay. Guess you're going to have to get that into us by the 15th of December. That would be at 2 p.m. Pacific time on Monday, December 15. And you will win a Planetary Radio t-shirt. And we're going to make some adjustments in the prizes soon, so stay tuned. But this time, definitely a t-shirt. And what a stylish piece of apparel it is, too. Oh, it is.

I got something for you. Really? Yeah, I keep forgetting to give it to you. I mean, here we went back to Palomar for last week's show to talk to Richard Ellis. And there is a gift shop, of course. And you know that I can't resist passing a space-oriented gift shop when I'm up there. So I bought you, look at this, I bought you a dwarf planet. It is a Palomar Observatory official dwarf planet, a squishy, rubbery ball with craters on it.

Here, let's bounce it. Just like a real dwarf planet. There you go. That's really cool. I own my very own dwarf planet made in China. Where else? Don't eat it. It's probably full of melamine.

All right. But my lead intake's a little low lately. Ooh. All right. We done? We out of here? We're done. All right, But my lead intake's a little low lately. Ooh. All right, we done? We out of here? We're done. All right, everybody go out there, look up in the night sky, and think about why Wookiees can't speak English.

Thank you, and good night. He's Bruce Betts, the director of projects for the Planetary Society. He has his own dwarf planet. I wonder if it's the Wookiee planet. I'm squishing it. I guess not. It's dwarf. No, no, definitely not. He joins us it's the Wookiee planet. I'm squishing it. I guess not. It's dwarf. No, no,

definitely not. He joins us every week here for What's Up. Next time, armadillos in space. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Music Music Thank you.