Planetary Radio: Space Exploration, Astronomy and Science - Tales From a 4 Billion Year Old Piece of Mars...On Earth

Episode Date: February 3, 2015

Robina Shaheen and Mark Thiemens tell us how an ancient Mars meteorite has revealed much about the red planet. Mat holds a tiny fragment of the rock in their UC San Diego lab.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

A four-billion-year-old piece of Mars in my hand, this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. We'll travel to a lab that has learned about the ancient climate of Mars from a piece of the red planet that made its way to Earth 13,000 years ago. But this was also the week NASA got good budget news, something Bill Nye will tell us about. And Emily Lakdawalla is ready with the best ever images

of a dwarf planet in the asteroid belt. Emily, Dawn, sneaking up on Ceres right now. Are we learning that this dwarf planet has a twin elsewhere in the solar system? Well, I think it remains to be seen how close the twindom appears once we get a little closer to Ceres and can see it in more detail. But it was really striking last week when these new images of Ceres came down. And Ceres, it's looking a little bumpy, a little cratered, but it's got this bright dot that has

been visible in the Hubble images and just keeps on being more visible in the Dawn images. And then a good friend of mine, Ted Strike, who does a lot of work with vintage data, pointed out how similar it looks to Umbriel, one of Uranus's moons. This white spot, which is quite striking. I mean, it's no artifact. You can see it rotating. Anybody have any guess at what it might be? It's definitely there.

It's definitely rotating with the moon. It's definitely brighter than the rest of Ceres, but you have to be really careful about calling it white. It's simply the brightest thing in the image. And Ceres itself is relatively dark. It's got an albedo of around 10, 11, 12 percent, which makes it brighter than comets, but still kind of on the darker side, more like the moon. And so it could be a fresh impact crater.

I think that's probably the guess that most geologists would make if you force them to guess right now. But it could be a lot of other things. And it's a good thing we've got a spacecraft getting a lot closer to Ceres, so it'll be able to tell us pretty soon. So here are these images that are now finally better than anything we've seen before, anything taken by Hubble or other Earth-based telescopes. It's just going to get better and better, right? Absolutely. And I just can't wait. And I'm so happy they're sharing images so quickly after they come down from the spacecraft so that we can all enjoy the ride as we get closer and closer to the biggest unexplored asteroid.

And I'm looking forward to having Mark Raymond back on the show to talk about his mission, the Dawn mission now approaching Ceres. Thanks so much, Emily. Appreciate it. Thank you, Matt. Check out her entries in the blog. There is also one about New Horizons and why it takes so very long to get data back from that spacecraft that is so very far away. Another of those icy objects that are going to make this year very exciting. She's our senior editor, our planetary evangelist, and a contributing editor to Sky and Telescope magazine. Up next is the CEO of the Planetary Society, Bill Nye.

Bill, the budget is out. Good news or bad news for planetary science and space exploration? Oh, boy, it's good news for space exploration. The proposal is to take the NASA budget up to $18.5 billion, which is fantastic. Science writ large will get almost $5.3 billion. And that means the planetary science ends up with about $1.4. Now, you know, Matt, the budget's out and we're all enjoying looking at these fine lines, these little lines with all these little numbers in them. But we were given a heads up. We got some hints. Because you know what's happening, Matt. The Planetary Society is in with the in crowd.

We know what the in crowd knows. We hang out with the cool kids. The cool kids. With the cool kids. That's right. And the other thing, this is an older reference, but we go where the in crowd goes and we know what the in crowd knows. So anyways, it was cool. It was really nice.

And the big thing, I think, for me and for John Culberson, who is the congressman who's going to be in charge of the committee who is responsible for all this, we have phase A funding for a mission to Europa. Phase A is NASA talk for let's get started for real. But this is big news, right? This is a first. Yeah, yeah, yeah. So it's officially in there. A mission to Europa is really going to happen. Now, the thing is, nobody is exactly sure if these plumes that we are presumed to be seeing in images from the Hubble Space Telescope, nobody's sure if they're real. And these would be geysers of seawater squirting off of Jupiter's moon Europa through cracks in its icy shell. Geysers would be streaming into space, into deep space. Perhaps if you could arrange a mission carefully enough, you would fly through the plumes, gather, if they're really there, through the plumes, gather, if they're really there, gather up Europanian seawater, see if there's anything alive.

It would change the course of human history. Is that a big deal? For 1.36 billion. And not all of that going to Europa, of course. That's right. You know, the Mars 2020 rover, by the way, that's also fully funded. Fully funded. So that's cool.

I don't know if you remember this, anybody, but this stuff gets fought about right up to the last minute. It's just a disgust. It's really something. So anyway, no matter whether or not you're in the U.S., whether or not you are working for the National Aeronautics and Space Administration, whether you're a Canadian space agency, European space agency, Japanese aerospace expert, Indian Space Research, Roscosmos in Russia, whoever you are, this is good news for space exploration. So it's cool. It's great. Thank you, Bill. Nice work.

Yeah, sure. Carry on. Let's change the world. He's the CEO of the Planetary Society, Bill Nye, the science guy. And we are going to go to Mars with a couple people who have a little telltale piece of that planet. You may be amazed by what can be learned from a 4 billion year old rock, a rock that came from Mars.

In addition to the Martian meteorite, you'll need an incredibly sensitive mass spectrometer and some very dedicated scientists. All three ingredients came together in a paper that caught my eye last December. Its lead author is UC San Diego project scientist Robina Shaheen. She works for Professor and Dean of Chemistry and Biochemistry Mark Thiemans in Mark's Stable Isotope Lab. I drove down the California coast a couple of weeks ago so that we could talk about the knowledge they and their co-authors have teased out of Allen Hills or ALH84001. Does that designation sound familiar? It should.

We started in Mark's office, but as you'll hear, we ended up in the lab, where I held a small, incredibly ancient fragment of the Red Planet. Our conversation started with the meteorite's carbonate deposits that could only have formed in the presence of water. The most important thing about this meteorite, because it is one of the oldest ones, 4 billion years old, and the carbonates are almost 3.9 billion years old in this meteorite because it is one of the oldest ones, 4 billion years old, and the carbonates are almost 3.9 billion years old in that meteorite. And that's the time when scientists thought that there might have been a lot of water on Mars at that time. And once you have abundant water, they thought that these carbonates might have been formed via biological

processes. That was the initial thinking back in 1996. And this is the oldest of these meteorites, right, that we have found on our planet? Yes. How long ago, roughly, did it arrive on Earth? It landed in Antarctic 13,000 years ago, but found in Antarctic around 1986. How did you manage to get a piece of what must be one of the most valuable meteorites on this planet? In this case, we collaborated with someone at NASA Johnson Space Center. But any scientist is allowed to apply for a piece of any of the Antarctic meteorites

through the Johnson Space Center where it's curated. You write a letter to them, tell them what you want to do with it and who you are, what your facilities are, and then they have a committee that meets twice a year and they approve it. So we've gotten other meteorites this way. This one came from our colleague on the paper, Paul Niles, who's at the Johnson Space Center. And this one was the best candidate for the work that's underway just because it does. We know it came from that period 4 billion years ago? Yeah, for the time period, it's the best

there is. It's probably the most studied of all the Martian meteorites, too. And the trick is to get a series of them over time from the oldest to the youngest. That way you can get some sense of, like Robina said, where was the water? How much did you have? What happened to it? Those are the big questions that are out there. Until you answer that question, you know, the question of life is a harder one to answer. You can look for it, but you have to have water. And the carbonates are made by water. That's why we went after them. This is your Rosetta Stone for water.

But there's more to the story than water. We get into the isotope balance. And I read this goes back to work that you did, Mark, like 25 years ago. Yes, I was seven years old at the time. That explains it. So it wasn't carefully thought out in all of its detail. Yeah, we've been looking at Mars meteorites for sulfates also, to look at the sulfur and the oxygen, also because you precipitate them.

In the same way that salt deposits from the ocean get dried up and left behind, the same thing happened on Mars, like evaporites, like the salt beds and whatnot. Mars, in a sense, is like that. You've got the salt beds left over in Nevada and whatnot. We didn't have as much water or ocean on Mars, and so there's just little tiny traces of sulfate and carbonate, which is what Robina measured in this one. We can study how much water was present at that time when these carbonates were formed. If they keep the ozone signature that they acquired, that means there was not much water. And the conclusion was, apparently, that it was pretty consistent with the other things that have been said about Mars in that far distant past, right? Yes. Which was that it was a pretty wet place, right, Mark?

Yeah, it was definitely wet. It probably wasn't a deep ocean surrounding the planet, but it was clearly wet. You see that now from the perchlorates and carbonates and sulfates. What's different about this that makes it a nice tracer ozone starts the whole process so if you have to start somewhere you start like on earth up in the stratosphere and ozone is weird it's it's labeled so think of it as having a fluorescent pink color in a sea of black and white so you can spot it easily the ozone stands out so once that pink gets mixed in with other molecules, you can spot it. So even though it starts in the atmosphere, if you take a rock and it's got a little bit of the pink in there,

and you know the rules for transferring the pink, you can see, oh, that came from the atmosphere. But it had to end up by going by way of water to the solids. So you get the gas, you get the liquid, you get the solid from the one measurement. That's the greatest bargain going, right? You get three different things all tied together just from following the pink label. It is mind-boggling that you can take this rock that spent billions of years in space, very possibly anyway, and 13,000 sitting on the surface of this planet before somebody stumbled across it in Antarctica, and say something about the climate of another planet.

Doesn't that just floor you sometimes? Yeah, it's great. I mean, really, that you can figure such things out by application of a set of fundamental principles, that you can actually go back in time billions of years. Like you say, it's another planet. It's a long ways away. And get all this information out of it. It's like Woody Allen once said, it's amazing you can think about things like this when

you can barely find your way through Chinatown. And then we were able to constrain how much water was present four billion years ago, how much was present in the recent past, because the isotopic signature for both the carbonate were similar in excess 17. Oh, the weirdness, the pinkness, the what Mark talked about. The pinkness, okay. That was the same. And had it been a huge ocean four billion years ago, that pinkness would have been gone. So that was an indicator the amount of water was not as we have on Earth even 4 billion years ago. So you're mildly disappointing me.

Let's see if you can disappoint me further as we near the end of this conversation. Sure. And talk about the other reason that some years ago made this meteorite, ALH84001, so famous. And of course, it was the finding about or the supposition about tube-shaped little cylindrical spaces also carbonate, right? And the speculation that came from NASA at that time was that perhaps these were generated by tiny bacteria, right? What does your evidence say? Well, what our evidence says is that the carbonate is made by the process that I mentioned with the transfer from the CO2 to the atmosphere through the water

and laying down a carbonate. It's consistent with that. It's consistent with what we measure in the atmosphere on Earth, and it's consistent with the experiments that Rabin has done and we've done in other labs. So from our end of it, it doesn't look like anything biologic. The carbon isotopes don't look like anything you would expect biologically. So from our measurements, there's nothing that would say that oh yes, this really looks like that isotope signature should be biologic. And, of course, my theory had always been that there were probably cats on Mars. But now that they sent a spacecraft named Curiosity, there's no chance.

I think I know where you're going with this. And your thoughts about the recent discovery, detection of methane by Curiosity, that cat killer? Methane is definitely made by bacteria. People, too, you know, depending on what you've eaten. It's a biomarker. The problem is it's not a unique biomarker. There are other ways to make methane. It's by a process called reduction.

You add hydrogen to carbon and you get methane. So it's not impossible that you're making methane in the planet interior by a hydrogenation reaction. That's something that could be answered, but you need another spacecraft to do it. It's to look for the associated molecules that would come with it. Is it hydrogenation or is it biological? So it's really interesting. Before we started recording, you told me that you would look for something altogether different. I'd look for nitrous oxide. That's my favorite molecule. It's made by bacteria, but on the other side of it, to make it by a non-bacteriological

process, or biological process for that matter. It's really hard. When we return from the break, we'll go with Robina Shaheen and Mark Thiemans into their lab and pick up the oldest piece of Mars on Earth. This is Planetary Radio. Greetings, Planetary Radio listeners. Bill Nye the Science Guy here. The Planetary Society's remarkable LightSail spacecraft is headed for space.

We want you to come along. LightSail is a small spacecraft propelled by photons from the sun. The excitement is building as we count down to our launch in May. Join us. Follow every aspect of the mission at sail.planetary.org. Let's change the world. Random Space Fact! Nothing new about that for you, Planetary Radio fans, right? Wrong!

Random Space Fact is now a video series, too. And it's brilliant, isn't it, Matt? I hate to say it, folks, but it really is. And hilarious. See? Matt would never lie to you, would he? I really wouldn't. A new random space fact video is released each Friday at youtube.com slash planetary society. You can

subscribe to join our growing community and you'll never miss a fact. Can I go back to my radio now? Welcome back to Planetary Radio. I'm Matt Kaplan. We've been talking with chemists Robina Shaheen and Mark Thiemans about their amazing work that has teased four billion year old climate information from a tiny fragment of a Mars meteorite. And not just any Mars meteorite, this is ALH84001, the rock found in the Antarctic almost 30 years ago that was once thought by some to contain microfossils left by Martian bacteria, a theory that was knocked down, in part, by the work done in the UC San Diego lab that we are about to enter with Robina and Mark.

So this is the extraterrestrial lab. This is a project here to measure the sun, the Genesis spacecraft that returned solar wind. Yes, of course. Yeah, the one that crashed. That is actually, this is called the extraterrestrial lab? Well, it is now. But this is where the sun was measured, is going to be measured.

And a lot of the analysis get made on this mass spectrometer here. Here is the meteorite. Oh, my goodness. So we have all varieties of meteorites that we've measured for different isotopes over time. Iron core meteorites, like we were talking about earlier. We have palisades from the core-mantle boundary, and then ordinary chondrites, which are the mantle, and then the carbonaceous chondrites, which are further out from that. We do moon rocks to study the sun.

Nice, pristine solar material. Yeah, the trick is figuring out what vintage it is, but it's there. So we're doing that and trying to understand that and try to get more at this life question. Where's the water? Where did it come from? Where's it going? Is it common? Should it be other planets with water like this? And so we're trying to get at the origins of water question with that, too. Yeah, that's the Allen Hills 8401 meteorite, the one that is presumably from, it's from Mars, but presumably had life. Ah, it moved. Look, look, look.

You know, deans aren't supposed to make jokes like that. Well, they just made me do it. So I almost feel like looking at this, we should be speaking in hushed tones. Yeah. Well, you'll wake them up. No, just, you know, reverence. You're right, though. It is.

It's something really unique and special. And it's, yeah, we're lucky to find things like this and be able to figure out what it is we found also. So it's terrific. You always feel that way, too. It's really unique to be able to handle such things and to study them, see what you can find out. I'm not going to grab it and eat it, but I don't know if you've heard the story. Yeah, I know. Kim Stanley Robinson.

Yeah, that's why I never bring him here, because if he's still hungry. Another product, I think, of UCSD, right? He definitely is. Yeah. Yeah, he's a good friend. I don't know if you know this story, Robina, but... I heard from Mark that he ate a piece and he's become Martian. Went up onto the roof of his house and looked up at Mars and ate a piece.

And so he's sure now that he is part Martian, exactly. Yeah, for 24 hours. Mars was hit by a meteorite, and some of the atmospheric gas is trapped into some of the small pores. And then its composition, especially for the nitrogen, was exactly the same as Viking has measured. So that's how we are 100% sure that it is from Mars, because the nitrogen isotopes, they are exactly the same. Perfect match. Yes. If I found it sitting in a stream bed, I wouldn't be impressed.

But looking at it here, it seems quite beautiful. It's just an ordinary rock. It seems quite beautiful. It's just an ordinary rock, but the exciting thing once you find out the isotopes, especially how nitrogen is exactly from the Mars and the other isotopic dating, that tells you it's from Mars, and then you start to have reverence for this rock. Before this, you would think, okay, it might be just another terrestrial rock from here, from our own planet. A far more substantial piece of this, you were saying, Mark, got burned up in your mass spec? Burned up, yeah.

In the name of science. Yeah, it worked. We learned a lot from it. We have to put on gloves because we always have some organics on our hands. And also we have to treat it with a specially cleaned spatula, forceps, and all the equipment that we require for the analysis free of organics. So it requires extra care. So here I have been hanging right over it with my filthy mouth. Was that not recommended?

I mean, we're not wearing any protective gear. It was in the ice for thousands of years. That's a good point. The Antarctic's not all that clean. Absolutely fascinating. So what else, other than dissolving it and putting it in the mass spectrometer, what else might be done with a sample like this in this lab? That's basically it, right? Well, we can look at it in smaller detail. Some of the sample there for the machine for measuring the genesis samples, it's possible we could look at smaller phases that contain oxygen and sulfur now by using a laser. Again, burn it up, but little tiny micron-sized dots to really look at it in some detail. We can do that. Also look at sulfur, which is stored in a regolith. Actually, understanding Mars is good for Earth

because it's a simple system to understand the complicated things. How does the atmosphere exchange with the surface? On Earth, it's a mess because you've got an ocean, you've got plate tectonics, you've got people, you've got life. But on Mars, at least you only have an atmosphere, a little bit of water and rock. So if you can understand that system and the photochemistry, which is already complicated, then you can use that to understand here a little bit better.

Well, I'm very glad you brought that up because that is, of course, a recurring theme on this radio show. Studying other worlds, we learn about this one yeah it's true if you look at just that simple question what does the atmosphere do to the surface that's all it seems simple gas molecules a surface rock and a little bit of water all right can't be hard there's only two or three molecules in the atmosphere of mars that do anything, and the rock is the rock. There's no plate tectonics. There's no volcanoes. It's still pretty complicated. You still end up seeing things that you don't expect,

and the species are the same. The worst pollutant in the atmosphere today is ozone. So trying to understand the ozone, again, the pink one, going through all the different molecules, you can do it on Earth, but it's just amazingly complicated. On Mars, at least you have a chance to see cleanly how long does it take and what's the pathway. And even then, it's a little hard, but you can do it. The Mars missions will help more because you need to know the atmosphere in more structural detail, and you can't do that with the meteorites. So like the MAVEN mission. Yeah. Mark, Robina, thank you

again. Sure. Glad to do it. Thank you. Robina Shaheen is a project scientist in the Stable Isotope Lab at the University of California, San Diego. Her boss, Mark Themans, is professor and dean in the Department of Chemistry and Biochemistry at UCSD.

My complete conversation with them and photos are on the show page reached from planetary.org slash radio. Bruce Betts is on the line. If he sounds a bit under the weather, it's because he is. He's well under the weather, but still here to join us for another What's Up segment. Hi. Hi, Matt. You poor soul.

Let's go ahead and go through this. We'll get it over for you. I know you don't want to mess up a perfect record, otherwise you probably wouldn't be with us. So tell us, what's up in the sky? We've got a plethora of planets, particularly in the evening sky, where we've got Venus super bright low in the west after sunset, Mars much dimmer and reddish above it. And then on the other side of the sky,

we've got Jupiter coming up in the east in the early evening looking super bright, Saturn coming up in the east later in the evening. So particularly that early evening is a planet party. So far, so good. Just keep rolling on. This week in space history, I always like to commemorate the anniversary in 1971 of Apollo 14. Not only great science, great exploration, but the first golf ball ever hit on the moon. Four.

Okay, take it easy now. Go ahead. Random space fact. I don't even think I'll put reverb behind it. So, as you may have noticed, at least those in the U.S., the Super Bowl was yesterday. If the solar system out to Neptune were the size of the coin they did the coin flip with at the beginning. That's 38 millimeters in diameter. They were 38 millimeters, 3.8 centimeters in diameter. And Alpha Centauri, the nearest star system, would be four football fields away.

I like that. And if the solar system were that big, would the Seahawks still have made that tremendous mistake? I'm pretty sure that all physics would have gotten really, really weird if the SOAP system were actually in that coin and the game would have been the least of people's concerns or interests. On to the trivia contest. Of the five currently IAU-recognized dwarf planets, which has the longest orbital period or year?

And what is that orbital period? How do we do that? Nice response for this. People wanted to go for that planetary radio t-shirt, which we will offer again next time. Here's our winner. Bruce has already told me that he's got it right. It's Joseph Hallman of Philadelphia, Pennsylvania, who said the answer is Eris, with an orbital period of only 564.1 Earth years. The figure I got was a little bit less than that, just by eyeballing it, you know, looking in the night sky. No, just the source I happen to look up at. So it's somewhere in the 557 to 564. It's really long. Half a millennium.

Yeah, I'm not going to wait up for it to complete its year. Congratulations to you, Joseph. We're going to send a shirt out your way. Let me tell you one other. This is from Joe Murray of Hoboken, New Jersey. We've heard from this Joe before. Like a lot of people, he said he still prefers Xena to Eris, but you know, what are you going to do? The IAU has spoken. He does say this.

At Perihelion, Eris is actually inside Pluto's orbit. Poor Pluto. Demoted and intersected. I'm glad you mustered up a little laugh for us there in the midst of your misery. I'm a professional. You are. Okay, tell us what you have for us for next week, and then you can crawl back under the covers. What are the names of the two stars in Ursa Major, that's the Big Dipper, that point, at least roughly, to Polaris, the North Star?

So you know how you learn to use the Big Dipper to point to the North Star. What are the names of the two stars? They're proper names. They have Ursa Major Greek letter specifications, but they also have friendly names, Bob and Joe, Jane. Okay, but not including those sample names. You have until the 10th, February 10th, that's Tuesday the 10th at 8am Pacific time to get us the answer this time around

you made it Guy, get back in bed drink plenty of fluids and I'll see you soon alright everybody go out there look up at the night sky and think about he's Bruce Betts, the director of projects for the Planetary Society, who joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its carbonaceous members.

Josh Doyle wrote our theme music. I'm Matt Kaplan of the Planetary Society. Clear skies.