Planetary Radio: Space Exploration, Astronomy and Science - Confirmed: Water Was on Mars!

Episode Date: March 8, 2004

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We're drowning in evidence of past water on Mars. This is Planetary Radio. Hello everyone and welcome back. I'm Matt Kaplan. Here's the big news, now almost a week old. There was water on them there planes. The Mars Exploration Rover science team made the announcement at a NASA headquarters press conference on Tuesday, March 2nd. Ben Clark was one of those with the TV cameras pointed at him, and he's our guest today. Then it'll be Bruce Betts with a rollicking what's up, including our newest planetary trivia contest. By the way, those of you who entered the contest or dropped us a line last week need to know that we had a little email problem.

We don't think we lost any of your entries or letters, but if you were expecting a reply and don't see it, please blame the fickle gods of the Internet. Let's get on to our conversation with Ben Clark. In addition to being part of the rover science team, this longtime planetary researcher is also chief scientist of space exploration for Lockheed Martin Space Systems Astronautics Operations in Denver. He's at JPL near Pasadena for the duration, and that's where we caught him right after a long shift on Mars time. Ben Clark, I almost have the impression that we should just spend the next 20 minutes

jumping up and down and shouting, there was water on Mars! There was liquid water on Mars! But let's be a little more substantive than that. Nevertheless, you guys must have been celebrating before, during, and after that press conference last Tuesday, March 2nd. Well, we certainly were, but I must say that the way that discoveries work is that you sort of creep up on them in some ways. So as we got in little bits of data that told us this looks more and more like water, could be real water, it wasn't as if there was suddenly a eureka moment and we suddenly did jump up and down,

but more of a gradual dawning and kind of acceptance by a lot of people that there was just so much evidence that it was looking really good. Now, I should say that we've been talking for several weeks with your colleagues, and each week I think they hinted just a little bit more that there might be some big news in store. But the announcement was made Tuesday, and you were part of that press conference. You were up there sitting up on the panel, revealing to the world the evidence, and quite a bit of evidence, for the presence, once upon a time, of liquid water at the Meridiani-Planum site.

Right. Well, as I said, it was just a matter of bringing a lot of things together. So you heard from a few of us, but there was a lot of people involved that looked at different aspects of this. And the inevitable conclusion seemed to be that we had two or three or four pieces of evidence that together were just in comfort to Burble, that together were just in comfort to Burble, that we had to go ahead and admit to ourselves this really looked like water had been sitting there and doing some things for a while. Well, good scientist that you were. You were reluctant until you had all of this corroborating evidence. And let's talk a little bit about that.

Go through it quickly. Anybody who's interested in more detail can see some excellent coverage on the planetary.org website, where you may already be listening to this program. But if we could go through a little bit, what were the three or four pieces of evidence found by the Opportunity rover, which convinced pretty much everybody that, as Steve Squires put it, that this site was once soaked in liquid water? Well, of course, the very first thing we saw was that with this outcrop, it really seemed to have layers. And that came in right off the bat as soon as we got pictures.

And the more we looked at them, the layers did really look different. And then there began to be perhaps the appearance of patterns. We did go over and measure just one of the layers with our APXS instrument, which is an instrument that can measure the elements that are in that sample. And that's where we got very high sulfur readings. However, at the time, these readings weren't as high as they ended up being, and the reason was that the rock was dirty. And later we went ahead and took our grinder and cut into the rock past the outside surface,

which was contaminated with just the dust from the atmosphere, and it was shielding some of our measurements. And once we got inside, we saw the sulfur was even much higher than we had measured on the outside. And that was really important because that means this whole outcrop probably has the salt, various kinds of salts in it pretty much throughout the material. One of the predominant or maybe the predominant salt might have been, I think it's magnesium sulfate, which you pointed out is known on Earth as Epsom salt. That's right.

On Earth it's Epsom salt, and you can buy it in the stores and has a variety of uses. But the one key difference is that Epsom salt is just loaded with water. It's about 50% water if you could actually heat it up and drive the water off of steam. And we don't think it can be quite that wet on Mars. So some of that water would be lost, but you would still have a little bit of water in it, and the version or the variety of magnesium sulfate in that case is known as the mineral kieserite. We also saw chlorine in those signals, which we interpret as chloride salts, like sodium

chloride. And most interesting of all, we found that in one of the rock units lower down, there was a very high concentration of bromine relative to the normal concentration. And that is kind of a telltale sign that you get whenever you have a salty water evaporating and producing salts of different composition. So as the water dries out, one salt will get near its saturation point and it will start forming crystals and it will precipitate out. And then pretty soon another type of salt will reach its concentration level

where it must precipitate because the water keeps being removed by evaporation. So you get a whole sequence. And in this way you can separate out sulfates and various chlorides, and then, as I said, the bromide comes out at a different time, and other things may be there as well. Now, is this related to the process, or not really the process, but what was observed, that there were some rocks that had some oddly shaped voids, which I guess the team decided were crystals that had perhaps formed in water and then been dissolved by them?

Yes, that's one of the most intriguing findings is we see these voids, which are not just simple rugged looking sort of roundish things, but instead they're very flat. It looks almost like one description has been a bird's feet. It looks like when a bird walks on mud and leaves the little toes imprinted down into the sand or the mud. But in this case, when we ground with our grinder called the rat, we found that these actually went very deep into the rock. And so what they really were were little platelets of crystals that were sticking up on the end, so to speak. And then apparently they've left. Now, they could have left by water dissolving them out,

or they could have left by some kind of erosion. Maybe they're very soft and make some leave, although they're down deep enough that one wonders about that. They're very soft and make some leave, although they're down deep enough that one wonders about that. But this is almost a telltale signature for gypsum crystals, although there could be other types of crystals, especially in a place like Mars. How about the famous blueberries? Well, the blueberries remain a very strong enigma. The blueberries, of course, are spherical particles.

They're beautifully spherical, actually. We call them blueberries simply because in the camera images, when we look at those images with the predominant red color of Mars and sort of the beige to red color of many of the outcrop materials, these little spheres, they actually look blue or gray in the images. They probably are more of a true color of gray, but they certainly are different. We do not know the composition yet, but we think in about a week to a week and a half, we should have the opportunity to measure them. We found a place where they're concentrated, and we're heading for that place right now. And when we get a chance, after we do a couple other analyses on the way,

we'll analyze the berries where they're concentrated, and then we're going to analyze right next to them, on a rock where they're not concentrated, and just subtract the information and see what we can find out. Our guest this week on Planetary Radio is Dr. Benton Clark, Ben Clark, who is a member of the Mir Science team. He is also chief scientist of space exploration for Lockheed Martin Space Systems, which is something I hope we'll have a couple of minutes to talk to you about at the end of our conversation.

But, Ben, if you don't mind, we'll take a quick break and come back and talk more about this tremendous evidence of liquid water on Mars. 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. We're back on Planetary Radio with our guest this week.

Ben Clark is a member of the MER, the Mars Exploration Rover Science Team, and Chief Scientist of Space Exploration at Lockheed Martin. Ben, we were talking about the blueberries. Talk a little bit more about the speculation and how they may have formed. I've read that it's now thought that they are concretions. Well, it's thought that they could be concretions. There's kind of two ways to make spherical particles like this that are well known to geologists.

One is that as a concretion, they can be formed just out of a liquid soil mixture. liquid soil mixture, and what happens is that something begins to aggregate around a center and then grows outwards as chemicals precipitate. An analogy might be the way a pearl forms inside an oyster in the sense that something grows as a sphere as multiple layers are put upon it. The mechanism here is a little different because it's a natural process with the chemistry of the surrounding fluid. The other way they can form those spherules, that is, is by volcanic activity where hot gases and rock are put high up in the atmosphere,

and then as they cool as they're falling, they will tend to assume a minimum energy shape, which is a sphere, that is, the droplets will just coalesce and form a spherical shape, and then if they cool before they hit the ground, they'll survive as spheres. And so that's a competing hypothesis, and in fact, maybe it isn't a volcano that does that, but in fact an impact event that has you create a crater that you spew up this hot material and it coagulates. Obviously, a process that doesn't require any presence of water. That's true, but of course, we don't know the composition of these yet.

If it turns out the composition is somehow of the elements we would associate with, say, carbonates or just some material that's not volcanic, then that would be one story. If, in fact, the composition of these looks very much like a volcanic material and we have the capability of detecting that, that would be another answer altogether. If these turned out to be volcanic in nature or from an impact, would there still be plenty of evidence left? This wouldn't shake anybody's faith that this was a site that had a lot of water. That's exactly right, because the blueberries are extremely intriguing.

They're very photogenic and so forth, and we like them. But they're not a key part of the story, and in fact, they're an uncertain part of the story right now. It could turn out they will be a very strong piece of evidence in favor of the water theory, or it could be that they're more or less irrelevant. How about that water? Do we have any idea yet? Might we get an idea of how long ago it was there and in what form? I mean, are we talking about just a lot

of wet sand and rock that water soaked into, or are we talking about a lake or a sea? Well, as far as how long ago it might have occurred, we do know that this region is covered with hematite. We don't even know for sure if the hematite is connected with these outcrops because we haven't actually measured the hematite and found exactly which component it is in. It could be in these spherules, but it may be more in the black granules we see on the surface.

We're going to get into more of that as we get out of the crater. But the hematite itself is a fairly old deposit. We can tell that by the geology around it. On the other hand, this outcrop in principle could be young, but there's nothing that says it couldn't be old also. As far as how much water, well, for one thing, there is soil or rock mixed in with this salt. The amount of salt is something like 40% maximum, but that's a very high value.

And that may be representing just the fact that you have either some volcanic ash or some soil, and the pore volume between each individual grain has been filled with salt, and that would turn out to be about that amount. each individual grain has been filled with salt, and that would turn out to be about that amount. What it does say, though, is that this particular bed of salt was not created far away from this soil or this ash, and so it might have been a shallow amount of water. Of course, it was the hematite that resulted in opportunity being sent to this site in the first place. Yes. We're very gratified, too, because we had said many, many years ago,

at least a decade ago, that we wanted to try and find a place that looked like it had evidence of chemical changes on the surface, such as you might get from hot springs and that sort of thing. We did find that from orbit with the instrument called the TESS, which discovered this hematite zone. We then landed, and the miniature version of that TESS is on the rover called Mini-TESS. And it's the thermal emission spectrometer, we should say. That's correct, yes. And it confirmed that we are in a hematite-rich area, but the real bonanza has been finding this outcrop

that maybe the hematite has been leading this here because of the activity of water. You mentioned speculation that began a decade ago, but you've been involved with Mars and landing on Mars for much longer than that. You are one of the few people involved with the Mars Exploration Rovers who was around and very active in the Viking missions. Right. I got involved in Mars a little over three decades ago, and then I was fortunate enough to have my instrument selected for Viking, so I flew on that mission.

And now I'm helping on a similar instrument, which is the APXS, on this mission, the MER. Which is the Alpha Particle X-ray Spectrometer. Exactly right. And it is, as we mentioned, that is what found the presence of these sulfates that suggested the salts we talked about a few minutes ago. Yes, that's right. You had a part in the Pathfinder mission as well?

Not really, except I was invited to come in and watch it for a couple of days, and that was a lot of fun. Well, with only a couple of minutes left, let me go back to something that I said we wanted to explore with you, and that is that you are the chief scientist of space exploration for Lockheed Martin, which may come as a surprise to some people. It did to me because we think of Lockheed Martin as the people who get us there and maybe help put together the vehicle that does the work, but not necessarily where you might find a scientist, a planetary scientist, who is a part of the actual research that's going to be done.

How does that work? Well, we've been very successful in being involved in a number of Mars programs now. For example, we built the Mars Global Surveyor and also the Mars Odyssey, the two orbiters that are providing the relay for MER, and also both of those orbiters have made breakthrough discoveries. And perhaps part of the reason is that we have endeavored to have a strong interest and participation in science wherever we can, because we feel that by understanding what the science objectives of a mission are, it helps the engineering group to better be able to produce a good product and good result.

Makes sense. And I want to add what you may not feel comfortable doing, really constant comments that we've gotten, accolades that have come from people like Steve Squires for the work done by Lockheed Martin on this and other missions, and, of course, Mars Global Surveyor, Mars Odyssey, very integral to the success of the rovers. Well, thank you very much. Let's finish up with what you're up to right now.

Just before we started to record this conversation, you said that you were working late this evening over on the Gusev side of Mars, where Spirit is, deciding where Spirit is headed tomorrow? Yes. In fact, we just finished analyzing a large rock, a very large rock at the Gusev area. We found it was quite similar in composition to an earlier rock, but there's also some very interesting characteristics when looked at under the microscope that indicate that perhaps this rock formed in a fairly wet environment

in terms of the lava or the magma that created this rock as compared to, say, a dry place like the moon. And so that's very intriguing, but the place we're really heading towards now is that crater rim, and we're going to be paring over that in just another, hopefully, week or so. And we might see down in there an outcrop, and then that would be an important target, or we might see something else that would be of great interest. If not, we're going to spend time to examine the various rocks that have been thrown out of that crater and then eventually head over to the hills to the southeast. So there's lots more excitement ahead.

In fact, I have a quote from you. You said just the other day, every day is a new day on Mars. You're just seeing the tip of the iceberg. Interesting choice of metaphor there, iceberg. Well, that's correct, and that's why I seem to get home late every night. Too many discoveries going on, but it's wonderful. Ben Clark, we'll let you get some rest. Are you on Gusev time or Meridiani time?

I'm on Gusev time at the moment, and then starting Tuesday I'll be back on Meridiani time. Well, rest up, whatever side of Mars you're on. We will look forward to lots more wonderful evidence and tremendous discoveries coming from the Red Planet. Okay, great. Ben Clark has been our guest. He is a member of the Mars Exploration Rover science team and is chief scientist of space exploration for Lockheed Martin. I'll be back with Bruce Betts in What's Up with Bruce Betts, the Director of Projects at the Planetary Society.

Welcome back, Bruce. Thank you very much. And we should say we have a special guest, actually many special guests. The Executive Director of the Planetary Society, is sitting behind us watching the live beginnings of what, the hearings of the commission, the President's Commission? Yes, the Moon-Mars Commission, looking at the future of human exploration. So if you hear that in the background, that's because the boss doesn't have headphones.

Say hello, Lou. Hi, everyone. Glad to be here. So there he is, Lou Friedman. Bruce Betts, back to you. What's up? Wow. Well, it. Glad to be here. So there he is, Lou Friedman. Bruce Batts, back to you. What's up? Wow. Well, it's hard to compete with that.

The planets can. We've got in the evening sky, you can see Venus really, really bright in the west shortly after sunset. You can see Jupiter really, really bright in the east at the same time. And in between the two, you can see Mars up above Venus, very dim, reddish, and Saturn very high in the sky shortly after sunset. A good time, a good time to look at the planets

lined up above your head. You told us last week that there was a day, it might have been Monday, that Venus was very close to the moon, very bright. And you know what? You were right!

Really? Yeah! You don't make this stuff up. Cool. Well, at least I didn't this time. Speaking of Venus, go. If you have a small telescope, take a look at Venus, that bright, bright object, and you'll see that it is about 60% of its face is lit,

sort of approaching half Venus, which will occur near the end of the month. I have friends who are about 60% lit. No comment. On to this week in space history. Seems just like yesterday, but it was actually March 13, 1781, that William Herschel discovered Uranus. Do you remember it, Matt? Like it was yesterday.

Fond, fond memories. CNN did a whole half hour on it. Nice job, Billy. Okay, on to Random Space Fact. The random space fact is that membership is online. We have all kinds of things. This is a rare insight into the daily life at the Planetary Society today. Darn, we're busy.

Go ahead, please. On Mercury, big, huge basin called the Caloris Basin. What's interesting is on the opposite side of the planet, the antipodal point, one of my favorite words to say, you see hilly and lineated terrain. I'm not making up this description. That seems to be an effect of this giant basin impact on one side of the planet causing strange terrain all the way on the opposite side of the planet.

Wow, like it just rippled right through and the ripples kind of stayed there? Better than I could possibly describe it. Nicely done. That's my job. It's the ripple effect. Forever after it will be known as the Kaplan ripple effect. On to trivia contest. Last week, we asked you, who is the project scientist for Voyager?

And we did get a lot of answers. A lot of people looked it up. And it is an old friend of interplanetary exploration, Dr. Ed Stone. It is indeed. Former director of the Jet Propulsion Laboratory, and he loves this project scientist job so much, he has continued it for 30 years, including through his directorship of JPL.

Cool tunes. I love the thought that Ed Stone is the director of this mission that has been going on for so very long. It's a wonderful thing. The project scientist, to be technically accurate. I'm sorry, the project scientist. In charge of the science on the mission. Sorry about that.

We got our winning answer this week, randomly chosen from a whole bunch of correct responses, from Richard Dock Kinney. Richard Dock Kinney of Ithaca, New York. That, of course, the hometown of Cornell University. A lot of good people coming out of there, have come out of there. Carl Sagan, Steve Squires, lots of others. Richard, we do congratulate you and you will be receiving one of those wonderful Planetary Radio t-shirts

which we hope will keep you warm as you go into spring there back in Ithaca. Yes, because they're 100% wool. No, that's not true. They're cotton. Let's go on to this week's trivia contest. No wrinkles, though. Just like this show. This week's trivia contest is a nice, complicated one to phrase. We talked about this recently, that one of the moons of Uranus has fascinating chevron-shaped features on its surface. Really an intriguing moon, intriguing discoveries

from Voyager 2. My question for you, for that moon, whatever its name might be, what Shakespearean play was its name taken from? Excellent question. Nice literary question this week. How do people enter? Go to planetary.org slash radio and enter our contest. Win yourself one of these fabulous Planetary Radio t-shirts. And please get your entry to us, if you can, by Thursday noon Pacific time. That's this coming Thursday noon Pacific time,

so that you can be fully considered as a contestant in this week's Planetary Radio Trivia Contest. I guess we're done unless you have any other announcements for us. I do indeed. Two things. On our website, planetary.org, one, just a reminder of our new feature we mentioned last week, the Earth dials, where you can look at sun dials from around the world, all live and in

color. The next, a reminder about our Astrobot DVD, Decode the Secret Code from Mars contest. It will be ending in about a week. You'll be able to decode these whenever you want, but if you want to be entered in the random code for Mars contest. It will be ending in about a week. You'll be able to decode these whenever you want. But if you want to be entered in the random drawing for prizes that include Lego model kits

and Planetary Society goodies like memberships, you need to enter within the next few days. You can go to our website, planetary.org, try to decode the secret messages from Mars on our DVDs that went to Mars carrying the names of 4 million people. Great fun. Great fun.

Great fun. Hey, look up in the night sky, everyone, and think about what kind of planet you'd like to see out there. Thank you, and good night. That was Bruce Betts, the Director of Projects for the Planetary Society. He is here each week with What's Up. And that's it for this week's show. Join us next time when we think we'll have an interesting talk about near-Earth objects and what we might be able to do about the ones that are too near for comfort.

Have a great week, everyone.