Planetary Radio: Space Exploration, Astronomy and Science - Mars Express Finds a Frozen Sea

Episode Date: April 25, 2005

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A frozen sea found on Mars. We'll talk about it on Planetary Radio. Hi everyone. Welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. The European Space Agency's Mars Express orbiter has found good evidence for a body of water, or rather water ice, as big as Earth's North Sea.

Gerhard Neukom is principal investigator for the camera that imaged it. He'll tell us about this and other exciting discoveries made in just the last few weeks. Later on, Bruce Betts will give the first of our new solar sail posters this and other exciting discoveries made in just the last few weeks. Later on, Bruce Betts will give the first of our new solar sail posters to the winner of this week's space trivia contest. Here are some of the headlines bouncing around our galaxy. You probably know about the asteroid belt located between Mars and Jupiter. Well, another belt of rocky debris has been found,

but this one circles a sun-like star that's 41 light-years away. It's an important step along the path to discovering small rocky planets, possibly like one called Earth. And speaking of asteroids, you can check out the newly revised Torino scale at planetary.org. It provides an easy way to classify both the likelihood that a space rock will hit the Earth and how much damage it might do. NASA has pushed back the launch of space shuttle Discovery by a week to May 22. This will give the return-to-flight mission planners

a few more days to finish testing and certification of new safety systems. And we're sorry to report the loss of one of humanity's greatest minds and voices. Philip Morrison died quietly at his home on April 22nd. Born in 1915, Morrison became part of the World War II Manhattan Project. The physicist would later help to create the Search for Ext for extraterrestrial intelligence, or SETI. Through his writing and work in other media, including many years as a columnist and book reviewer for Scientific American, he communicated the beauty and wonder of science to millions of laypeople, including yours truly. We've put a link to a description of Dr. Morrison's role in the history of SETI on the web page for

this edition of Planetary Radio. You'll find it at planetary.org. Emily is up next with the tale of a magnet that's slightly larger than the one on your refrigerator door and quite a bit more important. I'll be right back with Gerhard Neukom of Mars Express. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, is the Earth's magnetic field about to reverse direction? The Earth's powerful magnetic field is like a gigantic bar magnet sitting inside the Earth's core. It makes compass needles point north, helps migrating animals find their way, protects our atmosphere from being stripped away by energetic ions in the solar wind, and protects our civilization's power grid from being knocked out by solar storms.

But this important protective force can't be taken for granted. Geologists have discovered that every few hundred thousand years, the Earth's magnetic field collapses. The field always regenerates, but when it does, it may flip polarity, so that what we think of as the North Magnetic Pole would be located near the South Geographic Pole. Recently, though, magnetic field reversals have been rare. The last one happened nearly 800,000 years ago. We're overdue. Evidence now suggests that the Earth's magnetic field is weakening. What would happen to us if it actually reversed?

Stay tuned to Planetary Radio to find out. Gerhard Neukomm is Professor of Planetary Sciences at the Free University of Berlin. He is also Principal Investigator for a very special camera on board Mars Express, the European Space Agency's probe that is circling the red planet. I spoke to him a few days ago at his office in Germany. Dr. Neukomm, there is a lot that we can say about, that you can say about the HRSC, the high-resolution stereo camera. But can we start with this evidence that was mentioned very recently, only about a month ago as we speak, evidence of frozen seas near the Martian equator. We were stunned, really, seeing these huge plates, which we interpret as ice plates,

on the surface of Mars. It's a very level area, very flat, south of the Elysium volcanic province, the big volcano Elysium. And there, it's about the area of the North Sea that is covered there by plates that have moved against each other, partly turned, partly gone over obstacles. I mean, then channels have formed. So we have interpreted this as ice, as we have it on Earth, also in the Arctic or Antarctic oceans.

And you're talking about not ice of a couple of million years ago, which is pretty much what has been talked about from the evidence thus far, but existing ice? Yes, I think the top surface, okay, to make that clear, under the top surface layer, which is mainly dust, maybe a few millimeters, maybe centimeters or so, or decimeters of dust, we think there is still ice, or dirty ice, at least. These ice plates, they formed originally in a body of water. That means warm water must have come out of the surface, from under the surface, triggered probably by volcanic activity. And this is very plausible because the Elysium volcano is very close by. flowed into a very shallow basin-like structure about the size of the North Sea, a sea between Britain and Norway and Germany, Holland.

It's quite comparable. And the North Sea, which is something like 45 meters deep. Yeah. Also, on average, the North Sea is about 45, 50 meters deep. It's very shallow. These ice plates, which are gigantic, about 20 to 30 kilometers across, partly, which is about, say, 15 to 20 miles across.

Wow. People understand the measures. And these are gigantic plates, really, and they have moved against each other and split partly. So ice-free channels where the water came up form and it froze later then.

And you see it in a somewhat different color. You see very slight topographic differences. And you see how the plates had moved with respect to each other and collided or moved away and turned, so you can fit them back together partly. in light of the fact that we've gone in a handful of years from, well, there may be a little bit of water ice mixed in with the dry ice, the carbon dioxide ice at the poles, to now what sounds like an enormous amount of frozen water just barely under the surface, maybe just under the dust of dirty old Mars.

Yeah, that's true. We were stunned ourselves, and we had not expected this. And in fact, this is not theons, where we have an escarpment about 7 kilometers high and up on the mountain even on the shield, we have seen the remains of glaciers and the shield partly also still covered with layers of dusty ice.

So, ski Olympus Mons, I guess, will be the travel slogan. Maybe it would be rough skiing. I mean, quite some height differences, and I wouldn't recommend it, even if we could. But, yeah, I mean, there is a lot of ice still on the surface, we think. And on the eastern side of the shield, we've found very recently, that's very new, not published even, recently that's very new not published even uh... we have seen uh... the what uh... the interaction all volcanic uh... lava

flows on the shield with these layers of ice uh... where uh... the ice was melted and water flowed downhill and uh... assembled on the plane uh... on the plane's area at the foot of of of the shield uh... on the plains area, at the foot of the shield on the eastern side, and carved some channel system, and this channel system is also relatively young in Mars terms. I mean, what we think is old here on Earth, millions of years, is young on Mars, really because most of the structures are even billions of years old.

So there, the channel system we see there was carved about 20, until 20 or 30 million years ago. And I'm glad you brought up the volcanic activity, because this is one of the other discoveries that has been talked about, that apparently this evidence of volcanism is much more recent than had been thought, just like the evidence of water is surprising people. That's true. That was also a surprise. Had you asked me about, say, more than a year ago, one and a half years ago, so before the ESA mission, the HRC on the ESA mission got the new imagery and we saw new things, had you asked me about the age of the big volcano. I would have told you probably, oh, the youngest, probably a few hundred million years and not active anymore.

Now I think differently. We found some flank eruptions that are as young as 2.5 million years only. And this means if the volcanoes altogether, we measure that in a variety of places, were active over billions of years. The activity started more than 3.7, 3.8 billion years ago. So the shield was built up almost to its present height 3.7 billion years ago already, and the activity had gone on until very, very recently,

namely two and a half million years. So I would say it would be a very strange coincidence if that had stopped, the activity had stopped two and a half million years ago, having gone on over billions of years. So the idea is the volcanoes might still become active again. Wow. Dr. Gerhard Neukomm is our guest. He is a professor at the Free University of Berlin. He is also the principal investigator running the HRSC, the High Resolution Stereo Camera. Dr. Neukomm, if we can, after we take a break,

let's talk a little bit more about this unique instrument, which is sending back incredible images of Mars and allowing us to draw these quite stunning conclusions. We'll take that break right now and be back in a minute. This is Buzz Aldrin. When I walked

on the moon, I knew it was just the beginning of humankind's great adventure in the solar system. That's why I'm a member of the Planetary Society, the world's largest space interest group. The Planetary Society is helping to explore Mars. We're tracking near-Earth asteroids and comets. We sponsor the search for life on other worlds, and we're building the first-ever solar sail. You can learn about these adventures and exciting new discoveries from space exploration in The Planetary Report. The Planetary Report is the Society's full-color magazine.

It's just one of many member benefits. You can learn more by calling 1-877-PLANETS. That's toll-free, 1-877-752-6387. And you can catch up on space exploration news and developments at our exciting and informative website, PlanetarySociety.org. The Planetary Society, exploring new worlds. Gerhard Neukomm of the Free University of Berlin might be called the father of the high-resolution stereo camera on the Mars Express orbiter from the European Space Agency, ESA's ship which is circling the planet Mars and returning absolutely amazing photos and helping to build a body of evidence for a planet that is much more lively and perhaps even alive than we suspected.

that is much more lively and perhaps even alive than we suspected. Dr. Noycombe, tell us a little bit about the HRSC, which, for one thing, you waited a long time to get into the orbit of Mars, particularly after a great disappointment on the Mars 96 mission. Yeah, that's true. The Mars 96 mission, that was our great hope. That as the one with the Russian Soviets, formally. Right. And, yeah, we had a cooperation going on at the time.

It started at the time of Glasnost, yeah, when everything developed politically rather well, we thought, and we then agreed with the Russian, the Soviet or Russian side, to have a camera on board, which was what we have now as the HRC on the ESA mission. We had built, fortunately, two flight units, not just one, because the mission, Mars 96, was at the beginning two missions, as planned as two missions, 94 and 96. So we had built two flight units and put one on the 96 mission.

Unfortunately, this mission was not successful. It ended in the Pacific here on Earth and did not reach Mars. So this also ended our cooperation with the Russians. with the Russians, and then we thought here, on the West European side, thought very hard about how we could get our instruments into space again on another mission. I, together with my French colleague, PI of the current Omega instrument on the ESA mission, the spectrometer, we got together and could convince our national space agencies that we should try to come up with a new mission. And then it was Europeanized.

We could convince ESA to take it up, and so we got Mars Express in the end and could fly our instruments now with quite some success. Talk about this camera and the significance of the fact that it is a stereo or 3D camera. Yeah, it's the first real stereo camera that takes stereo images directly when flying over an area where we want to image not just flat images. Normally, you have one camera, one lens, one detector, and you take an image under some angle, flying over and coming back. Later, in another orbit, you take another

shot under another angle, and then you can also construct stereo imagery, and you get a so-called parallax, as we see at a slightly different angle with our two eyes. And you simulate that. And this is very cumbersome, and you cannot cover a planet really in this way very well. So your instrument does it directly. It does it directly, and we have nine channels, five stereotanks, so five eyes, so to speak, and four color channels. And so you go forward in flight, so to speak.

You use the forward movement of the spacecraft to scan the surface. Interesting. With these line CCDs. And since we look at different angles at the same time at almost the same spot on the surface, slightly offset in time, but just a few seconds, then we get stereo right away and color right away at the same time. So we don't have to come back again. So we get stereo imagery all the time and color imagery all the time at the same time.

Now, the point here being that the other spacecraft circling Mars, Mars Global Surveyor and so on, which have taken some wonderful pictures, a lot of work has to be done on Earth to turn those into either color or stereo images or both. There is wonderful evidence of the kinds of images that yours is returning. The HRSC is returning from Mars Express. They can be seen on our website at planetary.org. There is quite a gallery there.

And they are stunning. I mean, some of these, well, I guess typically you're getting, what, 10 or 20 meter resolution, but in some cases, quite a bit better than that. Yeah, we have a so-called super resolution channel also that gives us two and a half meters from 250 kilometers flight height, where 250 kilometers is about 150 or so, 160, 180 miles or so. And from that flight height, the super-resolution channel, which is an area chip, though, no stereo, gives us 2.5 meters per pixel,

and the stereo camera, the HRSC proper, gives us from that flight height about 10 meters. So we aim at taking pictures close to periapsin, that means the closest point in the elliptical orbit around Mars, the closest point to the surface of Mars, which is 250 kilometers or 260, 270 kilometers. So it's 10 to 12 or 15 meters resolution we normally get, and this can be enhanced by the super-resolution channel at even higher resolution. I'm sorry to say that we're almost out of time.

There is at least one more topic I hope to bring up, I will bring up, and that is with all of this new evidence of water, we are also seen sneaking in from not even really quite the fringes of science, but some very responsible scientific sources, beginning to speculate that with all this water, we may also see biological evidence, current evidence of biological activity on Mars. Any thoughts about that and how it fits in? Yeah, it could be.

It could be. And the PFS spectrometer has seen methane and formaldehyde, which is brought together with the activity of bacteria. This could be. Could be. But it's not absolutely convincing in the sense that it must be. One could also imagine it could be volcanic, hydrothermally related. But this would not speak against biologic activity, so it could be both, in fact.

Still more to look forward to with Mars Express. It's not your instrument, but I take it that there is this ground-penetrating radar is about to be turned on. Yes, that's true. The antenna will be deployed starting on the 2nd of May, and we all hope it all goes

well, because it's a little... We feel a little uneasy, because it's a little... We feel a little uneasy, because it's a very peculiar deployment, but okay. We all hope it goes well, and then we will be able to sound with

that instrument, the structure underneath, whether there is water or ice, under the surface, down to about a few kilometers. Wow. I didn't realize it could penetrate that deeply. Well, we will keep our fingers crossed on this side of the Atlantic for that one as well. And congratulations on the success of not only Mars Express, but your instrument, the HRSC,

the High Resolution Stereo Camera. Again, people might want to check out the gallery of images at planetary.org. They are quite beautiful, quite stunning, as is the evidence that is being returned. You sound like you're having a wonderful time, a much better time than you had in 1996. Oh, yeah, certainly. Well, thank you for joining us on Planetary Radio. It's been a pleasure. Dr. Gerhard Neukomm is a professor at the Free University of Berlin.

He's also the principal investigator for the high-resolution stereo camera now circling the red planet and returning incredible images and marvelous scientific evidence, as you've just heard. We will be back with Bruce Betts and his edition of What's Up after this return visit from Emily. I'm Emily Lakdawalla back with Q&A. The Earth's magnetic field could collapse and reverse polarity relatively soon, within a couple thousand years. Fortunately, the geologic records suggest that life on Earth won't suffer much.

The Earth's geologic history is punctuated by many extinction events, large and small. Some of these events have been blamed on asteroid impacts, others on massive volcanic eruptions, and others on ice ages. But no correlation has ever been found between the reversal of the Earth's magnetic field and extinctions in the rock record. Although a magnetic field reversal would temporarily expose the Earth to energetic particles from space,

the field regenerates quickly enough that no lasting harm seems to be done. But what happens to migrating birds and butterflies? No one knows. We may have to wait for the next reversal to find out. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio.

Bruce Betts is here. He's the director of projects for the Planetary Society. And this must be time for What's Up, our weekly look at what's up in the night sky and all kinds of other fun stuff. Bruce, welcome back. Hey, thanks. So tell us, what's up in the sky? You sure had a beautiful moon last night here in Southern California.

Yes, I arranged that. Thank you so much. Well, really, the whole Planetary Society did. Anyway, we've still got spiffy planets up there. If you're looking at the moon, you probably might have noticed Jupiter looking extremely bright. Hanging out in the east just after sunset, brightest star-like object up there, quite lovely. Take a look in a telescope or binoculars. See its moons, the four Galilean satellites, looking like little white stars right next to it, all lined up.

And you can also take a look at Saturn if you've got that telescope out, or even if you don't, it is overhead in the west, high overhead in the west-southwest in the early evening. And you can see Mars before dawn in the pre-dawn sky up in the southwest, looking kind of yellowish-reddish. And those are the planets we've got up to look at. Venus is starting to poke its head up, but it's still a tough view low on the horizon. I bet you've got other fun stuff for us. No, actually, I don't today. Well, what do you have that's boring? Oh, okay.

Random space fact! You still got it, don't you? Hey, I still got it. I still got it, man. Has? Hey, I still got it. I still got it, man. Has he got it or what? I sure do. So anyway, random space fact. You know, moons just don't get enough respect in our solar system sometime,

and I want to rectify that with this random space fact. We have a number of moons in the solar system that are bigger than not only Pluto but also Mercury. This includes our largest moon, Ganymede, the second largest moon, Titan. They're big worlds in and of themselves, and there's no end to the surprises we've had in seeing them as different worlds, even within one planetary system. So there you go. There's my plug for large planets this week. asked you about the soviet rover on the moon that they robotically operated on the moon during the 1970s called lunakod one and i asked you how many wheels did it have ah tricky how do we do matt mildly tricky question and uh we we had some complaints that the questions were too easy

still wasn't real hard, but it was tricky. In fact, some of the complainers got this one wrong. Because if Bruce had said how many powered wheels, the answer would have been the answer that we got from most people, which was eight. But there was a ninth wheel. Dun, dun, dun. And a good number of people did figure it out that there was a ninth wheel that I guess was sort of hooked to an odometer. Yeah. It was basically the odometer and an unpowered wheel. So there were eight, if you look at the pictures, very eight obvious powered wheels that the rover drove upon.

And then this ninth wheel they drug behind for other purposes, including as an odometer. So they know when to change the oil. Exactly, yeah. Well, here's somebody who got it right. One of that smaller group. I don't know, maybe a quarter of the people who got it right. I don't think, yeah, I don't believe this is a past winner. Keith Parker.

Keith Parker of Catonsville, Maryland said the Lunokhod lunar rover had a total of nine wheels. Ninth wheel was a surface evaluation instrument. It gave its controllers information about the average slope of the lunar terrain as well as providing drive wheel slippage information. There you go. Interesting detail. So lots more information. And because he knew that we were giving away, for the first time this week, a solar sail poster,

but he was used to us asking people what size they want. So he said he'd like a seven foot by six foot poster, please. JK, just kidding. Thank goodness. But he will be getting that Cosmos One solar sail poster. Yes, indeed. And if others of you would like to win a Cosmos One solar sail poster just for giving us a correct answer. Then answer the following question. What is the name of the cloud of comets thought to be the source of long-period comets in our solar system?

So these are ones with periods over at least, say, 200 or 300 years. But some of these comets have periods of a million years that come in. Recent examples being Hyakutake and Hale-Bopp. They're way out there. And there's a name for this place where we don't see the objects out there, but see them when they come close? Uh-oh. Tell us what that is. Send your answer to planetary.org slash radio.

Go there and find out how to enter and email us your answer to what the name of this cloud of comets way out there in the solar system going out to tens of thousands of AU, astronomical units, or the distance between the Earth and the sun. Uh-oh. By George. I think we've provided a hint. We never do that, but we did this time. And it's not by George, by the way. Get those answers in to us by Monday, May 2nd.

Monday, May 2nd at 2 p.m. Pacific time. And if you have the correct answer, you will be thrown into the pile with all the other people who got it right, and one of you will be chosen to win that Cosmos 1 solar sail poster. And then you'll be doing cartwheels in the aisles, filled with festivity. Which aisles? The aisles of your mind. The aisles of Langerhammer, I think. The Isle of White. I don't know. Anything else that we should know is going on before we say goodnight here? There are a lot of things you should know, but I don't know what they are. You can find a lot of

them on planetary.org. Good idea. People can still tune into my class, Introduction to Astronomy, at planetary.org slash Betts Class, and see an archive of those classes online. See, there's always something. Yeah, partnership with Cal State Dominguez Hills. Everybody, go out there, look up at the night sky, and think about what makes you happy. Thank you, and good night. I know what makes you happy. Thank you, and good night. I know what makes me happy.

Doing What's Up with Dr. Bruce Betts, the director of projects for the Planetary Society. Me too. He's here every week. Planetary Radio is produced as a public service by the Planetary Society. We'll have another brand new edition for you next time. Have a great week, everyone.