Planetary Radio: Space Exploration, Astronomy and Science - New Model for the Seas of Mars

Episode Date: November 15, 2010

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How the Seas of Mars Came to Be, 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. Alexis Rodriguez leads a group of planetary scientists that has a new theory about the vast amounts of water that once ran across the surface of the red planet. Does it provide a clue about where to look for Martian fossils? Emily Lakdawalla reports on the latest space triumph for China, while Bill Nye, the science and planetary guy, will chime in with his regular

commentary. And wait till you hear today's rendition of Random Space Fact. That will be right after Bruce Betts tells us about the night sky, and just before we give away a very cool new t-shirt design. As usual, we'll start with the Planetary Society's chief blogger. Emily, I think we need to start with another notable success by China. That's right. The Chang'e mission, which launched at the beginning of October, actually, has returned its first images from its incredibly low orbit over the moon, only 15 kilometers above the surface. It's orbiting that low in order to take good pictures, apparently, for a future landing, and they seem to have been quite successful.

The pictures are pretty amazing. There is one that is quite breathtaking of Laplace A, a beautiful crater. The lighting is perfect. That's right. You know, it's really amazing what a difference lighting makes. It's very dramatic. And this spacecraft apparently has stereo capability with its cameras in order to map the topography of the surface.

So it can turn its photos into 3D perspective views. And yeah, it's a really fine view of Laplace crater. A related topic to this is how these images were revealed. And I'll tell you, I would love to see President Obama standing on a stage pulling a drape off of a beautiful new image from someplace in the solar system. The Chinese had their premiere, Wen Jiabao. Yeah, it's quite different. I was musing about this. I wouldn't require the president. I'd settle for a senator or governor to unveil the photos in the same way. It's full of pageantry, of course, the way that they unveiled these photos. By the same token, when we get photos

that are released from NASA, we get them in much higher resolution. I have not seen the original resolution of these Chang'e 2 photos of the moon. So you win some, you lose some. More of these images to come? Absolutely. Well, at least I hope so. You know, it's hard to be sure with the Chinese. They did promise the release of all of the data from their Chang'e 1 spacecraft in the summer, and we actually haven't seen that yet. So I'm not going to hold my breath to see the data from this mission, but I would absolutely love to see it. And what we have seen are some really cool videos from engineering cameras on board the spacecraft that show things like the solar panels deploying and stuff like that,

that I'm about to post on the blog. Okay, so those may actually be up by the time some people hear this show. If they're not, keep an eye on the blog. One other thing, we got to go back to one of your blog entries from November 8th, Monday the 8th of this month, and that was this fellow Adrian Lark, who I think you've posted stuff from before. Yeah, I've posted his material once before. He's got his own home-programmed 3D generator for Martian surfaces that it's not something that takes a long time to render. It actually runs like a video game. It renders in real time, and he takes in high-rise data from Mars and produces just amazing flyover videos.

So you've got to go check those out. Talk about breathtaking. That one, I think, again, it was the one that you put most prominently on in the blog entry, is this fly not over but through a crater called Zumba, which is, oh, my God, it truly took my breath away. Yeah, there's some pretty spectacular vistas and cliffs and hills on Mars, and it's really fun to fly over them. All right, as always, lots to see on the blog at planetary.org slash blog. And Emily, thanks again. We'll talk to you next week.

Thank you, Matt. Emily is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine. And we're lucky enough to get her thoughts every week here on Planetary Radio. Back in just a moment, actually on Mars, after we hear from Bill. Hey, Bill Nye, the planetary guy here. Very excited this week because NASA is thinking about, they've designed a mission to send

a robot to the moon. You mean a rover to the moon? Like Spirit and Opportunity on Mars? No. No. Do you mean Mars Science Laboratory? No. No, this would be a humanoid robot. Now, to get a robot to walk around on the Earth takes almost 500 watts. To get a human to walk around on the Earth takes about 30 watts, because humans have such a sophisticated control system. And as we say, walking is a controlled fall. But if you were on the one-sixth gravity of the moon,

maybe the robot power problem wouldn't be such a big deal. No atmosphere to block your sunlight to the solar panels. It's a very exciting idea. NASA claims they could do it in a thousand days. That's less than three years. I say go get them, NASA. It's Bill Nye the Planetary Guy with your place in space. The Planetary Science Institute is one of those places that can be counted on

for new and exciting knowledge about our solar system, along with new theories about why the planets and other bodies look the way they do. Alexis Rodriguez is a research scientist at PSI in Tucson, Arizona. The journal Icarus has just published work by a group led by Alexis that proposes a fascinating new model for the formation of the ancient lakes and seas of Mars. If correct, it could tell us where to look for signs of past life. When I talked with Alexis a few days ago, we started with a comparison to our own warm, wet planet. Well, Mars right now is very different to Earth. It's like a frozen desert with

a very thin atmosphere. Very early in the history of the planets, both planets had very similar environments. Both planets had oceans both planets had very similar environments. Both planets had oceans and they had very high rates of impact cratering. So you're looking at an early history. The planets were very active hydrologic activity. Now, this lasted to about 3,500 million years ago. About three and a half billion years. Yeah, when suddenly something happened on Mars, right, like it started losing its internal heat and the atmosphere thinned out and basically

the planet froze over. So you have the development of a global cryosphere, which is a layer of ground that is like below the freezing point of water. That affected the rest of the hydrologic evolution of the planet. What happened back then is that in the case of Mars, liquid water was trapped in the subsurface. From that point in time until now, Mars has had a hydrosphere trapped under about two kilometers to six kilometers below the surface of the planet. So basically that played a very important role in all the hydrologic processes ever since. In the case of Earth, where we have like a topographic relief, we see that the topographic relief controls the direction of surface runoff. You have rainfall, you know, within a catchment area, and then rivers form, and they end up in lakes, and they open up to the seas. Yeah, and we can see the channels as we look at Earth. And, of course, we can also see some of these channels on Mars.

Oh, yeah. But then these channels, mostly, these are very ancient channels. They go back to the time when Mars was, like, very wet. After the surface of Mars froze over, the formation of a frozen layer pressurized the subsurface aquifers. So still, just like on Earth, the relief played a very important role in the hydrology.

But instead of controlling surface runoff, it controlled the distribution of where the hydrosphere was pressurized, basically in the low areas, in basins and basin margins. That's where you would have an inclined water table, and at the base of the water table, you would have an elevated hydraulic head.

The water would have been under some amount, maybe tremendous pressure. Yeah. So the question now is when that happened, how was like water released to the surface? So there are two modes that we can observe on Mars. One is zone of like catastrophic release and that's where you have vast collapsed terrains that are associated with some of the largest channels in the solar system. So these are places where the water would have reached the surface very suddenly and quite a bit of it? Yeah, and in very large volumes. These catastrophic releases of water produced channels, like some of them are 700 kilometers in width. So these are very large channels, right? We only see that on Mars in our solar system. I mean, these feature associations, right? This type of catastrophic activity released

large amount of sediments and fluids into the basin floors. That has been established by researchers over like the last 30, 40 years. The problem with this idea is that these zones of collapse and these huge channel systems are geographically restricted. They only happen in a few regions of Mars. In fact, you only see them really well developed in one region of Mars, like the region of South Chrysae. So how do we produce the materials that are infilling all the basins that we see on Mars when these zones of catastrophic release are restricted only to a few areas. And that was the motivation of this work that we published in Icarus. We found a region within the Martian lowlands that is not actually within a basin.

It's not contained within a basin, but it's actually covered by sediments. We looked at some degradational morphologies and we concluded that groundwater release within this region was driven by extensive systems of faults. Basically, you would still have the same conditions, a pressurized aquifer, but as opposed to releasing the water catastrophically

through one point, one conduit, you would release it gradually over a very large area that contains fractures or cracks. And this would have happened more slowly and maybe over a longer period of time? Yeah, it would have happened more slowly because, like, the amount of water discharged would have been pretty much like spring discharges on Earth. The length of time of this process, you know, we estimate it would have been like 2 billion years. The length of time of this process, you know, we estimate it would have been like 2 billion years.

Yeah, so that's a very long time to bring water up to the surface from deep-seated aquifers within the crust. And this is based not just on our observation of the surface, but what we now know because of recently acquired data, I assume including the radar data that is looked onto the surface, we know that there's still a great deal of water underneath the surface of Mars. Well, the problem with the radar data is that it has difficulties in penetrating terrains that are cratered because of like the echo. But yeah, we do know like the radar has identified some layers of ice within the northern plains and it has identified stratified ice in the polar caps as well. If this mechanism is actually what formed the majority of the surface water on Mars billions of years ago, what does this say about where we should be looking at Mars, where we should be sending, well, for example, the Mars Science Laboratory, Curiosity? Well, I think the Mars Valley, which is one of the sites that is being considered

as a landing place for the mission, right? I think that could have like a very good potential because if we're looking for water, you want to find water that is coming from the subsurface, but that has been in the subsurface for a long time. If you release the water gradually over a long time, you have stratification as well. You may have a stratification of subsurface brines deposits on the surface. So I think the Mars Valley, I would think it's a very good choice. It's an Arabia Terra that's, you know, in the region where we predict this aquifer may have started upwelling. That's Alexis Rodriguez. predict this aquifer may have started upwelling. That's Alexis Rodriguez. When we return, he'll tell us where he thinks we should look for signs of life on Mars. This is Planetary Radio. I'm Sally Ride. After becoming the first American woman in space, I dedicated myself to supporting

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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. My guest is Alexis Rodriguez, a research scientist at the Planetary Science Institute. He leads a group that has developed new thinking about how many of the seas and lakes of Mars formed billions of years ago. We have a link from our show page at planetary.org slash radio to an article about this on the National Geographic website. The evidence will have to come from far beneath the current surface of Mars,

or just possibly from craters that may display the planet's distant past. The size of craters, if you look at the upper rim of the craters, you're going to get inverted stratigraphy. So you could actually look into the deepest stratigraphy by examining the rim of the craters. And the central peaks, they could actually be bringing up very deep-seated materials as well from the subsurface. So when you say inverted stratigraphy, it actually is sort of flip the layers upside down? Yeah, that's the idea. So the layers on top would be the oldest. That's what you would see around the rim of the craters. I would also say that impact craters,

they've played a very interesting role in the hydrologic history of Mars. To study the history of water on Mars, I would advocate like going to investigate either infilled craters or like buried craters, if that's possible in the future. When you talk about buried craters, I mean, this brings up a whole other area of research and speculation on your part that has to do with the possibility of perhaps giant cavern systems that started out as ice-filled craters? Yeah, this is work that we did back in 2005. And what we found is we were looking at regions of catastrophic collapse, large-scale collapse on Mars. These regions that I was mentioning are associated with these channel systems, right? And then we found that these regions are actually surrounded by huge zones of surface subsidence,

where you have highlands that show evidence for surface warping and sinking. So they've collapsed, basically. As opposed to collapsing, they've actually warped. They haven't, like, broken up into mesas and knobs. So you can actually see the surface texture and landforms, but they are just warped. They've gone down. Collapse would involve the rupture of the surface. So does this suggest, from what we know of Earth geology, that these caverns are laying underneath these areas?

What this is telling us is that there has been removal of ground materials from underneath these areas, but also tell us that there had to be like very high permeability because obviously you have to transport sediments and water over long distances to like a point of rupture where, you know, you have the initiation of the channels. What we saw is that investigating these zones of subsidence, we looked at a zone where retreat, like a scar retreat, has actually exposed the internal structure of these zones of subsidence. And then we found that there appear to be impact craters that are buried and they become interconnected. When I say they become interconnected, I mean that they're a series of troughs or like valleys that extend from one crater to another. And this is exposed onto the surface, right? So the way that this was interpreted, craters produce networks

of fractures and faults around them. When they are proximal, these fractures overlap and they produce zones of like high permeability. Now, if you think about impact craters and you like rewind back in time and you go to the times when these craters were being buried, craters would actually accumulate water. I mean, if you have a surface and there's rainfall, craters are going to be zones where the channels are going to converge into, right? So you're going to have deformation of lakes or like fluidized sediments, right? Sure. And that water would freeze. Exactly. So now when the craters are buried, you still preserve lenses of ice in the subsurface. And these lenses of ice would be surrounded by fractures. When these fractures overlap with the

fractures of another crater, so you have water and you have high permeability. You heat up the system and you give it some gradient and water is going to flow. That could actually explain why we don't see large scale rupture of the surface is because basically there's a lot of water in the surface and there's very high permeability that allows for like distal migration of groundwater. I want to make sure I understand the significance of this because it sounds like if you are correct, and maybe in sort of the best of all Martian worlds,

there would still possibly be a tremendous network, interconnected network of water channels and reservoirs under the surface of Mars. Yeah, yeah, that's correct. And I think that's the case. Yeah. How would we determine that this is actually the case? I mean, one possibility, of course, would be sending Curiosity to the landing location that you mentioned.

What would really be able to tell us that this is how Mars is structured? I mean, would we have to send up a drill that would really go down a long ways? We know that there are millions of buried craters of Mars. I mean, that's a fact. We already know that because, you know, we can map them out. To actually know what percentage of these craters contain volatile rich deposits, I think that, you see, these deposits could actually be to a depth that they are not recognizable through image data studies alone. I think that would involve like human exploration. Sounds good to me if that's one more reason for humans to make the trip. I like that idea. One other thing that has come up in the coverage of this, certainly in the National

Geographic article that I mentioned, and has been commented on by some of your colleagues in planetary science. Is this possibility of, gee, if we look in the right places where this briny water came to the surface, would you be surprised if we found fossils, or at least microfossils? Are you comfortable with that? I think it is predictable, you know, we'd find fossils. I know that development of hard parts, questionable, right? But on Earth, like we see fossils that are preserved, fossil leaves.

Right. But that contain no hard parts, right? And the other thing as well is that, and this is just like pure speculation here, right? If life existed in the near surface or the surface of Mars in environments that were highly radioactive, then my view is that hard parts would have aided life to continue to

exist. They might have helped to shield the life. Yeah. My goodness, wouldn't this be something to find? And I hope this is all being taken into account by the people who are deciding where MSL would go. I guess with the instrumentation that that very advanced rover will carry, it might just be able to find some of this evidence. Yeah, let's cross fingers. Yes. Alexis, we are pretty much out of time. I wish we could continue, and I will look forward to talking to you again. I look forward to talking to you again about these topics.

It's really interesting. Very exciting stuff, and I want to thank you for joining us. Alexis Rodriguez is a research scientist at the Planetary Science Institute. He's based in Tucson, Arizona, and he is the primary author of this recent work, speculating on how oceans may have formed in a very different way than has been considered in the past, a way that might have meant that they would have lasted much, much longer and might have left some fascinating evidence on the surface that could very well be waiting there on the red planet for us to find.

Sorry to say that once again this week, Bruce Betts is on the Skype connection. I was really hoping to catch you face-to-face so that I could give you your gift, which I am holding in my hand that I picked up at the Kennedy Space Center. But you're just going to have to wait, big guy. It's not moving, is it? No, no, it's not moving at all. Not anymore, anyway. It stopped a few days ago.

Oh, geez. What's up? Well, in the night sky, we have Jupiter still being the dominant bright star-like object up in the south in the evening. And you can always check that out with a small telescope, and the little dots next to it are the Galiland satellites, the Galiland moons. We also have in the pre-dawn sky super bright Venus now starting to pop up in the east shortly before dawn, and also higher above Venus you will find the much dimmer but still quite interesting Saturn. We move on to This Week in Space History. 40 years ago, Lunokhod 1 became the first

wheeled object on the moon. Yeah, and it was recently imaged. I just saw a shot of it someplace, maybe in Emily's blog, not sure. I got to week in space history. This week in space history, Bruce Betts was born some number of years ago. Happy birthday. It was huge. Huge. Thank you. I was tipped off. Okay. Well, thank you very much. You're welcome. Yes. The most important of all dates in this week in space history. as I'm sure everyone will agree we've got another person who sent us

a clever random space fact introduction shall we play that? clever indeed, here it is the random space fact the random space fact the random space fact random space fact

random space fact the random space fact the random space fact random space fact random space fact Random Space Fact. The Random Space Fact. The Random Space Fact. Random Space Fact. Random Space Fact. The core. The Random Space Fact.

The Random Space Fact. Random Space Fact. The Random Space Fact. Random Space Fact. The Random Space Fact. The Random Space Fact. The Random Space Fact. Random Space Fact. Random Space Fact. Random Space Fact. I don't know about you.

Random Space Fact. Random Space Fact. I could barely contain myself, and I've heard that four or five times now. Jim Booz. Jim Booz. Brilliant. Put that together. Original music with a little help from his friends, you and me.

Absolutely brilliant. Thank you so much, Jim. And you get a Planetary Radio t-shirt for that one, for sure. That was great. And we'll accept more, folks. We've got another entertaining one to play next week. Send yours as an MP3 file to planetaryradio at planetary.org, and you might get a shirt out of it. All right, here's your fact. PlanetaryRadio at planetary.org, and you might get a shirt out of it. All right, here's your fact. The Hubble Deep Field that most everyone has presumably seen has 3,000 galaxies in this picture,

but it's an incredibly tiny part of space. Actually, in the constellation Ursa Major, the one that gives us the Big Dipper, the angular distance that we're seeing is the equivalent of a tennis ball 100 meters away. So you're standing at one end of a football field. Your buddy holds up a tennis ball. It's the amount of sky that that tennis ball blocks out. And in that, they see these 3,000 galaxies. Amazing. That is truly amazing.

Let us move on to the trivia contest. And we asked you about globular clusters. And I asked you approximately, since not everyone agrees on the exact number approximately, how many globular clusters are attached to the Milky Way galaxy? How'd we do, Matt? I'm just going to tell you that we had a first time winner who was chosen by random.org, Chris Kesterson. Chris Kesterson of Alexandria, Louisiana, who gave us the answer that most people did, 158, according to a recent count. Other people were a little bit looser.

They said 150 to 160, but you had said approximate. I did, because you can't nail it down because the experts don't agree. It depends on how you define what's attached and what's not and what's being absorbed and things like that. Now, I actually like David Kaplan's response even more. He said that his Milky Way bar has 158 delicious globular clusters. Man, now I'm hungry. They're chewy.

Anyway, we had a little... If you leave it out in the sun, you end up with open clusters. We also had a little... If you leave it out in the sun, you end up with open clusters. We also had some people... Trying to make humor there. There were people who reported that their estimate that about a quarter of these came from elsewhere. Giorgi told us, it seems that Andromeda, our neighbor, has as many as 500. He says, we got to go out and get some more of these things from, you know, borrow them from some other neighbors or something. We can't let ourselves be outstaged or upstaged on the local group scene.

Well, we are upping the recruiting. Don't worry. Yeah, Globs, the Milky Way wants you. Come on over. Anyway, we're going to give Chris, actually, he gets the very last set of DVDs of Wonders of the Solar System from the BBC, presented by Professor Brian Cox. But we got a great prize for this new contest. The question comes from my son, Kevin. And that is, tapping into Greek mythology, Ursa Major, which I mentioned a moment ago, the big bear.

I had never thought about this before. But you look at the constellation, and the part that's supposed to be the tail of the bear is actually quite long. Same thing for Ursa Minor. But bear tails are not long. So what's up with that? Well, of course, Greek mythology made an effort to explain this. And what was that? Why is Ursa Major's bear tail so darn long, according to Greek myth? Go to planetary.org slash radio, find out how to enter. Wow, nice work. Pass along my congratulations on coming up with that great question. Anybody who enters this time has until the 22nd of November, November 22nd, Monday at 2 p.m. Pacific time, to get us your answer.

And here is the prize. This is pretty cool. I got one of these, and I love to wear it. It's a t-shirt, a t-shirt called Beyond Earth that has little images of 23 different spacecraft that have explored our solar system. It comes from the Chop Shop and you can go to chopshopstore.com and find this shirt there. It's normally a $23 item. But you know what? If you buy a copy of this shirt on the website, chopshopstore.com, they're going to give $5 of every purchase to the Planetary Society.

But we're going to give away one of these shirts if you can come up with the right answer. Good luck and good hunting. All right, everybody, go out there, look up at the night sky, and think about scrunchies. Thank you, and good night. Scrunchies? Do you have them laying around there like I do? Because, you know, I've lived with a lot of women in this house. Oh, women have them too? Yeah.

Okay. He's Bruce Betts, the Director of Projects for the Planetary Society, and he joins us every week here for What's Up. Big news from Deep Impact Epoxy about Comet Hartley-2. We'll hear it next week on Planetary Radio, which 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. Редактор субтитров А.Семкин Корректор А.Егорова