Planetary Radio: Space Exploration, Astronomy and Science - The Ancient Snows of Mars

Episode Date: August 5, 2013

When she was learning to forecast the weather in Hawaii, Brown University grad student Kat Scanlon didn’t suspect it would help her uncover evidence for rain or, more likely, snow that helped shape the surface of Mars billions of years ago. Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Mars and Hawaii, more in common than you think, 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. Kat Scanlon is the graduate student who is lead author of a paper that says precipitation on the red planet, read rain or more likely snow, helps shape at least some of its mountains and valleys. We'll talk with her in a few minutes and we'll learn why Bill Nye has the knack. With what's up and another space trivia contest waiting for our big finish.

First up, though, is the Planetary Society's Emily Lakdawalla. Emily, you have just been itching for those wheels on Curiosity to get to rolling across the red planet. Are you feeling pretty good today? Yes, I am. They finally started making tracks, and they have at last made it west of their original landing position, so that's big news.

Of course, they took a major excursion eastward to go to that spot called Yellowknife Bay, where they found some really cool rocks. But it was farther away from their eventual destination. So now they've made up for all that lost time, and they're headed southwest to the toe of Mount Sharp. And one year in, one Earth year anyway, as people hear this show, we will have hit that anniversary. It's kind of interesting to take stock because, you know, it has been a year and they've gone just over one kilometer and have drilled two holes.

So, summarized that way, it does not sound like a whole lot, but they've certainly gotten their feet under them. They figured out how to use all the instruments on this incredibly complicated machine. And so they are really ready and now they are really making tracks. They're actually really not stopping for science much along the way on this drive. They are stopping here and there, though, and all along the way taking beautiful pictures. There is one here, vertically exaggerated, contrast enhanced.

But the first thing I thought when I saw this beautiful image was, haven't I hiked there? It really does seem very familiar. And there's a reason for that. Because, you know, you like to go hiking in places where you can see cool looking rocks. And it is definitely cool looking rocks that have brought curiosity to this place. Although it's not the rocks you're thinking of. If you look off into the distance, you see these amazing looking hills with these layers in them. But those layered rocks are probably actually windblown sediments. They're not terribly interesting if what you came to Mars to do is to look for

environments for ancient life. It's actually at the base of those rocks that you want to be looking at. There's some lower topography that still does have layers in it. And that's where the cool minerals are that probably talk about Mars's more wet history. And so that's what Curiosity is going to be driving several kilometers to go check out. All right. There is much more cool stuff in this recap of Curiosity's first year, an update anyway, that Emily put in the blog at planetary.org on August 1st. But let's jump forward to when you did on August 3rd,

because I just love your enthusiasm about what this little rover managed to do by looking up. It's just so cool. And this is, it's amazing. If you look at the animation that I put together, it's not very detailed, but you could be forgiven if you thought it was Cassini watching a couple of Saturn's potato-shaped moons passing right by each other. But it's not Cassini, it's Curiosity taking video of Phobos and Deimos passing by each other. Right now, all we have is a little tiny pixelated window on the view, but it'll get a lot better once Curiosity gets enough time and bandwidth to send all of the frames down. In the one full res frame that we have, Phobos' shape is absolutely unmistakable, and it's going to be an amazing product once everything gets on the ground. be an amazing product once everything gets on the ground. Well, I don't think anybody will be sorry if they take a look. As I said, it's an August 3rd entry in the blog at planetary.org. Emily,

thanks so much and have a good time celebrating that anniversary of Curiosity's year on Mars at JPL. I will with ice cream. I'm looking forward to it. Emily Lakdawalla, she's the senior editor of the Planetary Society and our planetary evangelist. And not only is she a contributing editor to Sky and Telescope magazine, but don't you have the cover article this month? I do. Go to the newsstand and check out my article all about water on Mars in this month's issue of Sky and Telescope magazine. Thanks, Emily. Bill Nye is next. Bill, welcome back. You know what I want to hear about. How was your first appearance at the NAC? The NASA Advisory Council,

it was fabulous. Actually, it was okay. But here's the thing. The NASA Education Public Outreach Budget has been, in a sense, cut to zero. And the premise of the bit, as we say in comedy writing, is to allow the Smithsonian to take over informal education, that's any education that's out of the classroom, and the Department of Education to take over all the education. But where do these two entities get their information about, let's say, a mission to Jupiter, a mission to Mars, a mission to Mercury. They get it from NASA itself. So this is a big deal that has to be worked out. I guess it was done this way in order to shake things up. I suppose. But, you know, I've said before in this program, I'm really troubled by taking this effort away from the missions themselves,

the people who really want to crow about what they're doing. Turns out that NASA has 2,500 websites. And so there was talk about consolidating these, you know, it's not good for the branding. You know, I don't care if you live in the United States or not, but NASA is the best brand that the United States has. You travel anywhere in the world, the National Aeronautics and Space Administration is well known and respected. But when you have one organization with apparently a sixth of the U.S. government websites, there's something that's not quite being managed right. So that's what we talked about is tightening that up. So that's what we talked about is tightening that up. And then, Matt, the way things went, I sat in the audience for the council meeting.

So I'm on the committee that's part of the council, and people asked about the asteroid mission. They asked about the space launch system. They asked about the Orion capsule and the pace or the cadence of launches. These are the old questions that the Planetary Society has been bringing up for the last four or five years. Is this really the best way to spend money? And other people were asking the questions. It was a chin-stroker. Well, I'm glad you were there, and it's nice to know that you're on that team as well as ours. Representing the Planetary Society, Matt.

We're going to change the world. Thank you very much for that report and for taking the time out of your vacation to bring it to us. Thank you, Matt. He's the CEO of the Planetary Society, Bill Nye the Science Guy. Now, the snow on Mars. Mars. She goes by Cat. That's Cat Scanlon, the geological sciences graduate student at Brown University that we'll talk with today. Cat led a computer modeling effort that has provided new evidence for precipitation and probably snow in the distant past of Mars. Kat, thanks very much for dropping by your office for us on a Saturday afternoon

so you could talk to us about this research. And congratulations on its publication in the Geophysical Research Letters. I also want to congratulate you because you're a grad student and you're the lead author. How cool is that? I should be getting them out faster. I need to get some more of those papers. So always the guilt, I guess. There's nothing wrong with some ambition, I suppose. But trust me, you're doing well. First, tell us, what is this field of, is it pronounced orography, which I'd never heard of?

I guess what people would really call the field in this case is flow topography interactions. So in general, just the dynamics of the atmosphere interacting with mountain ranges or in the case of Mars, usually crater rims or volcanoes, I guess. from your university, Brown, describing this work, that talk about your work in a place that I do not normally think of in connection with Mars, and that's Hawaii. But as I read further, I realized that when you go to a place like Honolulu, Honolulu's down low near the water, but up behind it are those beautiful, spectacular mountains. There's this enormous amount of rain up there, not nearly so much down below in Honolulu. And that is somehow related to this research. Yeah, you know, it was a lesson I kind of learned the hard way when I was studying meteorology at UH Manoa. Every meteorology major has to take one of two lab courses in forecasting,

because the graduate school turns out a lot of really great forecasters for NOAA. And I knew I wanted to work more on climate models and preferably on other planets. So I was like, why do I have to take this forecast course, but it ended up being one of the best ones I ever took. Every day, every morning, we would start the class with this contest that was ongoing where we all had to predict the weather for the next day in Honolulu and at a station somewhere in New Jersey, I think, that we sort of arbitrarily picked. I couldn't figure out. I was, you know, they posted the results for the whole class and we were all kind of competitive about it. And I was doing pretty well in predicting the wind direction

and the temperature and everything like that, but for some reason I was at the bottom of the class in predicting the amount of rain. I was always predicting way too little. And it turned out that the weather stations we were supposed to be predicting at were at the Honolulu Airport for the majority of the measures, but they had us predicting the rain at a tiny little station up in the mountains in Manoa Valley. So the orographic effect screwed me over in forecast class. And so I had to from there. It's certainly much more difficult in New Jersey.

How did this relate to what you found on Mars? And where did computer modeling come into this? I was taking a class on the history of water on Mars and we were studying some somewhat older papers about the debate between whether they had been carved by, the valley networks had been carved by precipitation or groundwater. Given my time in Honolulu, I thought, well, if they were carved by precipitation, there would have to be at least a little bit of evidence of some sort of interaction with the topography.

So on the upwind side of these ridges, we would expect to see more rain. And at that time, one of my advisors, well, several of my advisors, colleagues at the LMD in Paris had just finished developing one of the first GCMs for early Mars. So what's LMD and GCM? Oh, gosh, I'll try to pronounce LMD. I think it's Laboratoire de Météorologie Dynamique. Très bien. The meteorology department at the University of Paris, as I understand it. A lot of the great Mars climate

modelers are based out of there. And there's also some great ones at Caltech and Ames and a few other places. So they developed this model that we could use. And from that, I could figure out what the wind directions were and also look at things like just the temperature and everything that also help you predict how much precipitation there would have been. So you took this model, the general circulation model developed by this French lab, and you basically applied it to Mars. And you found, as we've heard from a couple of other people in the past, that this model kind of naturally fit what you saw?

Absolutely, yes. So we also used a terrestrial, what's called downscaling in climate science. So GCMs predict what's going on at the resolution of like two degrees of latitude or longitude. And we wanted to look at these valley networks on kilometer scale resolution because that's the imagery we have. So I also used sort of an analytical model that some workers at Yale and elsewhere had developed that allows you to take GCM data and sort of apply it to topographic data, and then you get results for what the orographic precipitation is at a much finer resolution. So once we put that in there, we were pleased to see that the wind directions the model predicted

as being the most, the GCM predicted as being the most common in each of these places, were also, when you fed those into the finer scale topography model, exactly lit up where we see all the valley networks. Wow. So tell us about this once upon a time precipitation on Mars. I mean, how long ago are we probably talking about? It's on the order of 3.7 billion years. There's a little bit of spread between the Valley Network's age, but they're all right around, clustered pretty close to then. We'll continue our conversation with Kat Scanlon

about the great downhill skiing ancient Martians may have enjoyed. This is Planetary Radio. Hey, hey, Bill Nye here, CEO of the Planetary Society, speaking to you from PlanetFest 2012, the celebration of the Mars Science Laboratory rover Curiosity landing on the surface of Mars. This is taking us our next steps in following the water and the search for life, to understand those two deep questions. Where did we come from? And are we alone? This is the most exciting thing that people do. And together, we can advocate

for planetary science and, dare I say it, change the worlds. Hi, this is Emily Lakdawalla of the Planetary Society. We've spent the last year creating an informative, exciting, and beautiful new website. Your place in space is now open for business. You'll find a whole new look with lots of images, great stories, my popular blog, and new blogs from my colleagues and expert guests. And as the world becomes more social, we are too, giving you the opportunity to join in through Facebook, Google+, Twitter, and much more. It's all at planetary.org. I hope you'll check it out. Welcome back to Planetary Radio. I'm Matt Kaplan. The snow on Mars may have fallen billions of years ago, but Kat Scanlon and her colleagues believe it may have helped shape the current surface of that planet,

the surface that spacecraft from Earth have mapped in great detail. So this is ancient, very ancient weather. Why are you looking at the possibility of snow rather than the kind of rain that we see carving these valleys in Hawaii? Right now, the climate models are having a really hard time finding a physically plausible mechanism that would make Mars warm enough to have rain back then. So the sun was much less bright at that time. And so unless you're pumping in massive amounts of greenhouse gases, it's very hard to keep Mars warm enough to rain. Or in some cases, if you make certain assumptions about the planet being very dark and absorbing more sunlight, or about some assumptions about the size of cloud particles, then you can say,

OK, Mars may have been warm enough to rain every now and then. But nobody has yet come up with a physically very robust way to prove that Mars could have had a warm climate at that time in the GCMs. But it must have warmed up now and then, right? Because that snow had to melt and run down those mountains. That's one hypothesis that my co-authors have been working on, is that every now and then maybe there was intense volcanism that released a lot of sulfur dioxide. Sulfur dioxide at first is a very potent greenhouse gas. And the problem is later on as it stays in the atmosphere, at least on Earth, it starts to form reflective particles. And those actually make it colder. Some researchers are showing that maybe the time when it stays warm lasts long enough that you could melt this.

So that's what we're working on next is working out how fast the snow could melt under a range of plausible conditions. So it's not hard to get a few days a year where it warms up Mars. It's just hard to get it consistently warm. Kat, you told me that the upcoming MAVEN mission may actually be adding some additional data to some additional work that you folks have done that didn't make it into this press release. Yeah, we're all really excited to hear what MAVEN finds out about how much of an atmosphere early Mars had. So one of the big potential differences between Mars four billion years ago and Mars now is that it may have had an Earth-like surface atmospheric pressure. One thing we tried to do with this paper is see what the precipitation

patterns could tell us about what the surface pressure on early Mars was. And we found that if you had twice of Earth's atmospheric pressure, so two bars, the rain or snow would fall in the wrong place on Warrego Valleys, which is one of the really beautiful, well-developed valley networks that everyone in planetary science loves to look at. And that's because the wind needs to be coming from the west in order to get valley distribution that we see. But if you have a very thick atmosphere, the jet stream never migrates all the way that far south seasonally. That's something some other scientists have tried to look at also by looking at things like the smallest craters from that age that are preserved in river sediments.

The workers who did that work, who were at Caltech, I believe, found that something on the order of pressure had to be below 1.6 bars. So we're seeing similar results there. 1.6 bars. So we're seeing similar results there. And MAVEN will really give us the quantitative data that we need to see how fast Mars has been losing its atmosphere. What else are you working on? And what do you look forward to working on as you head into, I hope, a very promising career? With this project, the big follow-up we're working on is the other researchers have looked at the morphometry of the valley networks, so their dimensions, and from that have worked out actually how much water was flowing through them when they last were being eroded actively. We'll be doing some computational modeling to see if we

can match that rate of flow and what kind of climate does that. The ultimate interest in finding out what kind of weather it was, rain or snow, and how warm it was and what kind of climate does that. The ultimate interest in finding out what kind of weather it was, rain or snow, and how warm it was and what was causing this warming is, of course, working out how favorable early Mars was for potential microbial life. So if it was very warm, then, you know, that's nice because chemical reactions all occur faster when temperatures are higher and life is just a bunch of chemical reactions. But if it's colder, maybe there are some papers, people have argued that the transition from prebiotic chemistry to early life might be easier in ice because you get veins within the ice that

would help concentrate all these chemicals together because the pure water is freezing out into the ice grains. There are a couple of images in this press release from Brown University, July 23 press release, one from Mars Reconnaissance Orbiter, one from Odyssey. It would seem to me that the data you were able to get from these orbiting spacecraft, you really couldn't have done this work without these robots up there in space. Oh, absolutely. FEMIS, MOLA, and CTX, I think, are the three instruments that were used to make those two images.

MOLA was really great because that was the laser altimeter that actually gave us the topographic data. It wasn't in orbit as long as we would have liked, so Lola and MLA have been mapping the topography of the Moon and Mercury, respectively, and those were able to stick around a little longer and get really great high-resolution maps. So we'd all really love to see another MOLA someday that might be able to hang around Mars a little bit longer and get some higher-resolution data, but we're totally delighted to have what we have from it. And then Themis has 100-meter coverage of the whole globe. So that's very nice. And CTX is five meter coverage of much of the globe. I have a lot of love for all three of those robots, I guess. Best of luck as you continue to look at how Mars came to be the way it is,

partly through the weather that it used to go through many, many, many years ago. Really has been a pleasure talking to you. It's been great talking to you, too. Kat Scanlon is a grad student, a graduate student, at Brown University in Providence, Rhode Island. She's also the lead author of this piece that was just published by the Geophysical Research Letters about snowfall, snow that may very well have given Martian valleys and Martian mountains

the look that they have today, that we have seen in such great detail from orbit. We'll take a look in great detail, well, somewhat detail, at the night sky in our regular visit with Bruce Betts. That's in What's Up, coming up in just a moment. time once again for what's up on planetary radio don't look over there look at me don't look at her it's radio i don't have to look at you. That's part of the importance of radio. Anyway, he's here. It's Bruce Betts, the director of projects for the Planetary Society. Try not to be distracted because we want to talk about what's up.

What's up where? Oh, right, in the night sky. It's a planet party, Matt. I know. I just keep saying it. But Venus is still super bright, low in the west. In the evening sky, Saturn will be migrating over towards it in the next few weeks. It's looking yellowish in the south. And we've got in the pre-dawn a festival going on with Jupiter being the really bright object over there in the east.

They're all in the east. But it's highest up and brightest. Below that, you've got reddish Mars, much dimmer. And way below that, tough to see, very low on the horizon, whitish Mercury. Similar in brightness to Mars, but different color. It's a midsummer solar system party. It is. It is. They're having what you said.

We move on to this week in space history. It was one year ago we were partying at the Pasadena Convention Center with thousands of other people doing Planet Fest for the Curiosity landing on Mars. And I hear it's still working. Yes, that's right. Yes, doing great stuff. Farther back in time, 1990 Magellan entered orbit about Venus. The radar mapper revolutionized our understanding of Venus. And even farther back, 1960, the first object was successfully recovered from orbit, sent into orbit and then recovered.

We'll come back to that. Oh, because I was about to ask. I know you were. Just wait. People are going to help us learn what that is. Let me move on to random space fact. I know you were. Just wait. People are going to help us learn what that is. Let me move on to random space fact. Oh.

Joe Engel, astronaut Joe Engel, is the only person who had gone into space before becoming an astronaut. Let me see if I can do this way. What? At least by U.S. Air Force definition, which is somewhat lower, he had gone into space on the X-15, crossing their space threshold of 50 miles, before he was then selected as an astronaut and went a couple hundred miles up. Only four times as far as the X-15. Even less than the higher flights. You love that space plane as much as I do. Oh, yeah. It's totally cool. I used to worship it. I'd watch those

drops live on TV when they're dropping it from the... Oh, it's totally cool. Yeah. So before you go on to the contest, I got some other special stuff that I really want to share with you. of the contest. Yes. I got some other special stuff that I really want to share with you. You know, we get so much mail and I read every bit of it, folks, every bit of it. I just don't have time to respond to all of it. So thank you all for all the wonderful things that you say about the show. This was simply a mistake on my part because otherwise I'd have brought it up when we were talking about dog names around the solar system. I just missed this from Pete Carboni. Peter Carboni, Scooby-Doo is a rock on Mars found by sojourner. Nice. Isn't that cool?

Yeah, I suppose if we go to object, yeah, okay, I'll give you that. And I, of course, love the Scooby-Doo. I love it. I thought you'd appreciate the opportunity to do your impression. So this one, apropos of nothing, it's from Alex Strickland, who I don't think has entered before, out of Morristown, Tennessee. Alex, I'm sorry to say you didn't win, but I sure liked your message. Here's his special greeting to us. It's because of your podcast about a telescope a year ago and I'm outside on every clear night.

Thank you for a wonderful podcast. Wow. That's very nice. Thank you, Alex. We love to see things like that. Okay, now I think we can actually talk about the contest. What'd you ask us? I asked you what two solar system bodies did the Vega missions, Vega 1 and Vega 2, explore? How'd we do? Fascinating. Everybody got this. Big response. I think it must be the t-shirt. Our winner, if this is correct, is Nick Ray, a first-time winner out of Peoria, Illinois.

And he said that it was Venus and Halley's Comet. That is correct. They went off to Venus. They dropped off probes, balloons for the atmosphere of Venus, and then were redirected to be part of the Halley Armada. The Armada, right. I love that. We're attacking.

We also got this from Randy Bottom. His answer, he got it right, of course. He said, I always wanted to drive a Vega, almost got a Nova, but he didn't think that was what we were talking about. No, no, no, no, no. You know what? What? You should be, no, no, no, no. You know what? What?

You should be really glad, Randy, you did not get a Vega. I don't want to sound like the car guys, but... Not so much. Not so much. Finally, this, and it's just a question for you before you get to next week's question. Yeah. From yet another entrant, Kathy Hutchison. She said, Cosmically, she knows knows the perspective isn't all that different, but do what we call constellations look the same from other planets in our solar system?

Mr. Astronomer? Why, yes, they do. There would be the tiniest, tiniest difference, but any measurement with your eye, they're going to look the same. And by the way, pardon me, Dr. Astronomer. Thank you. So, Nick, we're going to send you a T-shirt. The rest of you, this is your chance to get that brand-new Planetary Radio T-shirt.

Okay, flashback to this week in space history. What was the first object successfully recovered from orbit? Sounds like I'm making a joke, but I'm actually looking this time around for the actual answer. What was the first object successfully recovered from orbit? So launched by humans into Earth orbit, and then something came back through the atmosphere and was successfully recovered. What was that? What mission was it associated with? Go to planetary.org slash radio contest. You have until the 12th of August monday august 12th at 2 p.m pacific time to get us this answer one more thing yay you know i missed because i was at jpl what

three times in one week this time i got you three rockets oh that's so cool They're rocket erasers. Does that mean they erase rockets? No, they're pencil toppers. That's very cool. This is what they sound like in the packaging. Thank you, Matt. I love my gifts when you go off and go visit JPL. I'm glad. I'll keep it up. They decorate my office.

All right, everybody, go out there. Look up the night sky and think about shrink wrap. Thank you, and good night. Got some right here. I won't pop it. That's not shrink wrap. That's bubble wrap. Pop dots. That's what we called them in college. That's a tasty candy, I think. He's Bruce Betts, the director of projects for the Planetary Society,

and he does join us each week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by a grant from the Kenneth T. and Eileen L. Norris Foundation and by the snow-loving members of the Planetary Society. Clear skies. Thank you.