Planetary Radio: Space Exploration, Astronomy and Science - Are There Puddles on Mars?

Episode Date: March 30, 2009

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Puddles on Mars? This week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Principal Investigator Peter Smith told us months ago that the best of the Phoenix Mars Polar Lander mission might be yet to come. We got proof last week when a team led by Milton Renno announced that what looked like drops of liquid water on one of the Phoenix landing struts were exactly that. Dr. Renner will tell us much more on today's show, including how those droplets managed to stick around, possibly for days.

Bill Nye, the science and planetary guy, will tell us what a new electric car and space exploration have in common. And Bruce Betts will help us find a planet or three in the night sky. Emily Lakdawalla has the week off, so we've got a Q&A classic for you. Discovery is back on Earth. The shuttle successfully delivered to the International Space Station everything from new solar wings to a replacement urine processing unit. Listeners tell us the combined ISS and shuttle were a spectacular wandering star. There's an amazing story at planetary.org by my colleague Amir Alexander.

It tells the tale of the first asteroid to be found and tracked before it impacted Earth. Fragments were later found in the Sudanese desert. Here's Bill. Hey, hey, Bill Nye, the planetary guy here, vice president of the Planetary Society. And last night, I did an awards presentation for scholarships for middle and high school kids who are excited about science and excited about the future at the California Science Center. Earlier this week, I was at the unveiling of the Tesla Motors Model S. And S means sedan. This is an all-electric car that will outperform almost any sedan you can think of in acceleration, in comfort, in room inside, and of course, in carbon footprint. And that car is being designed by Elon Musk, who is on the board of the Planetary Society

and who serves to inspire young people in middle and high school to pursue careers in science. Now, what does this have to do with space? Well, the same guy inspiring the same kids is building the SpaceX Falcon rocket and the SpaceX Dragon capsule to take maybe some of these kids into space. This guy is building this stuff in the U.S., inspiring U.S. students to pursue careers in space exploration and car design, to be engineers and scientists of the future, so that we can address climate change, carbon footprints, and explore where our world is with regard to all the other worlds. And all this stuff happened to me in the course of a couple days. Very exciting time, my friends. The Planetary Society attracts heavy hitters.

And so all of you that are tuned in, I'm going to call you all heavy hitters as well. We have the ability, through gently influencing people in governments around the world and in our own work and our own jobs, gently influencing people to pursue math and science and explore space. Ever so slightly, all of us, I hope, are going to change the world. Well, thanks for listening. I've got to fly. Bill Nye, the Planetary Guy.

The first thing you need to do is follow the link at planetary.org slash radio to see what Nilton Renaud says are drops of liquid water on Mars. Renaud is a professor of atmospheric, oceanic, and space sciences at the University of Michigan. His presentation at last week's Lunar and Planetary Science Conference represented work by scores of colleagues, including Phoenix Mission Principal Investigator Peter Smith. It explained how the salts, or more precisely perchlorates, in the Martian soil around Phoenix could lower the freezing point of water enough to keep it liquid, even in the terribly cold conditions near the Red Planet's North Pole. I talked to Nilton not long after he had returned to the Ann Arbor campus.

Dr. Renaud, I want to thank you very much for joining us on Planetary Radio. And let me start with this statement. Everybody knows that there is no persistent liquid water on Mars, right? Right. Except for really saline water. And that's what we were talking about. Highly saline water. Your research, was it inspired by these images of these little droplets of something on the legs of the Phoenix lander? Two things. First is that one of my graduate students here at the University of Michigan, his name is Manish Mata, he did an experiment to look at the fact of the Phoenix landing thrust at the surface of Mars. And what he discovered was that Phoenix was going to completely remove the top soil and

expose the subsurface ice during the landing. And so that first image that we had of the ice was basically we were pushing for Deuce to search for, to test his experiment and theory. Then what caught my attention was the things in the strut. From the thermodynamics, my background's really in atmospheric thermodynamics, I knew that liquid water was very unlikely, but because it's too cold in the landing site region, but it would be possible if it could get warmer. But a saline water would be really, really easy to make there if there was enough salt on the ground. Before we get to those salts, first of all, this is the first I'd heard that it was one of your students who realized what the effect of those thrusters would be as Phoenix set down on Mars. And, of course, at first, there was a lot of worry about how those would really hurt your

ability to do science at this site. And as Peter Smith has told us on the show, it turned out to be a blessing in disguise. Exactly. We were, I would say, optimistic about the success of the landing. And we were really excited when we found out how much soil was going to be removed because it's a science experiment. We can calculate some of the properties of the soil based on how much soil was removed. That's why we were very interested in the images under the lander. That's yet another point that I have not heard before, that you were actually able to tell more about the composition of the soil starts expanding. When the soil starts expanding

it gets fluidized and it behaves as an atmosphere with molecules that are very heavy. So that means that the speed of sound goes down by orders of magnitude, more than two orders of magnitude in the soil. Then when the next blast comes in, that creates shock waves, supersonic shockwaves through the soil. And we have been calling this explosive erosion. And the explosive erosion is constrained by the porosity and cohesion of the soil. So if you know how much soil was removed, we can calculate those two parameters. And that's what we did.

And we have a paper that we are planning to submit to science, almost ready to go. You can't see it, but I have a big smile on my face because this is such a wonderful story. It's just fascinating to see how much science could come out of something that looked like it was only going to be destructive.

What is the name of your student once again? Manish Mehta. Well, we will congratulate him and we'll watch for that name in the future of planetary science. Yeah, thank you very much. He's a very creative, very smart guy. And, you know, then the other thing that he discovered was that he did some calculation. We published the paper last year on JGR. It was that just the compression of the plume over the ice would probably melt a very thin layer of the top of the ice.

That's why when I saw those things on the strut, I immediately thought, well, that was probably a mixture of the soil and this mud created by the melting of a little bit of ice that splashed under the lander. And then we kept watching it, taking images as frequent as we could. The next thing that caught my attention was that those things were first moving around and that there is different growth between particles of different size. And that's consistent with saline solution getting more or less diluted

depending on how much water it's absorbed from the atmosphere. And we will have to put up a link to the University of Michigan page where I found these images of these droplets. It looks exactly like, you know, watching droplets of water condense on the side of a cold glass. Exactly, yes, exactly. Watching them merge and how long does it look like these actually persisted as a liquid on the leg of Phoenix? I think at least for about five days, because initially the mean temperature was going up during the first, about first 50 sols at the surface of Mars, and then the temperature starts slowly going down. So while the temperature is going up, those things are absorbing water from the atmosphere and getting a little bigger,

and the amount of salt is diluting. And then when the temperature starts going down, then that water was going to start to freeze. But there is also superimposing those in the diurnal cycle. So we believe that those droplets would partially freeze during the night and then melt again during the day. And the other thing that really caught our attention was the fact that there is a change in the brightness of those droplets. And change in brightness is associated with change of phase of water. Like the liquid appears to be darker than the ice or the salt crystals.

And of course, one of the other things that we learned from Phoenix is that indeed this soil around the lander was extremely salty. That's true. But first we saw those things before we discovered the salt. And so at the beginning, there were people that were very skeptical because they were saying there is no evidence that there are salts there. And what I was saying is, I'm just looking at the images. And what's going on in the images tell me that there is salt there. But then after we detect the perchlorates, then it was amazing, I think,

that the case became much, much stronger. Phoenix Lander co-investigator Nilton Reno will tell us more about liquid water on Mars when we return. This is Planetary Radio. I'm Robert Picardo. I traveled across the galaxy as the doctor in Star Trek Voyager. Then I joined the Planetary Society to become part of the real adventure of space exploration. The Society fights for missions that unveil the secrets of the solar system.

It searches for other intelligences in the universe, and it built the first solar sail. It also shares the wonder through this radio show, its website, and other exciting projects that reach around the globe. I'm proud to be part of this greatest of all voyages, and I hope you'll consider joining us. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio. I'm Matt Kaplan. Liquid water on Mars? Right on a leg of the Phoenix Mars Polar Lander? It almost sounds too good to be true. But Nilton Reno says, believe it.

The University of Michigan researcher is recapping for us his presentation at last week's Lunar and Planetary Science Conference. Reno leads the team that figured out how the salty soil found around Phoenix could protect those delicate droplets. Just like spreading salt on a road in the eastern United States. In fact, I'm sure it happens where you live in Michigan. A lot here. That salt, which lowers the freezing point of the water. Is it fairly clear that it raised it to a higher temperature than was actually being experienced there? Yes, yes. In fact, especially because the strut there is in the shadow. Well, not especially. Because the strut is in the shadow, but also under the lander,

that buffers the diurnal change in temperature. So the strud is warmer during the night and slightly colder during the day. And the fact that it's colder during the day inhibits the evaporation. But it's cold, but it's still warm enough for you to, even with the most conservative salt that we found there, perchlorate of sodium to be liquid at the temperatures that we have there. Solorate of sodium, to be liquid at the temperatures that we have there. So here we were, though, up at the North Pole. If you were at the equator and had a similar composition of soil, a similar level of perchlorates

or other salts, wouldn't we expect to see even more liquid water? Exactly. You need two things. You need the south. You need a little protection against the really high temperature that you get during the day. So that could be just a thin layer of soil. And you need the source of water. So what I claim in the article that we submit to the Journal of Geophysical Research is that if those conditions are met, and they are met over a very large area of Mars, then it's possible to have those small

pockets of liquid salty water. Should Mars Reconnaissance Orbiter be looking for puddles on Mars? I don't expect to see huge puddles, because that would be really speculation. Don't know how much salt there is in the soil. Those things can concentrate the salt. My guess is that there will be small pockets of liquid brines around Mars, but I don't know. Maybe pools are possible if all those conditions are met. I didn't do that calculation. And I think it's a little bit too much speculation to say that.

Well, you're just being a good scientist about it. It certainly gives Mars Science Laboratory a little more to look for. Oh, yeah. You know, in my talk at Lunar and Planetary Science Conference, I end up with a little joke that I said. The follow the water theme should be update to follow the liquid water. That's good, I like that. Yeah, people like that. In the press release that was put out by the University of Michigan, where you are at the moment,

there is one sentence that stands alone, on its own in a paragraph, and it is this. Certain bacteria on Earth can exist in extremely salty and cold conditions. That's all it says. It's not my sentence because I'm not an expert on life. I think people, this really grabs the attention. I think it's probably the reason why they put it there. And we don't know.

I think my view is that we know life here on Earth. We know that it was evolving in less saline conditions. We know that liquid water is really necessary for life. We know that we have life in very extreme conditions that we didn't expect to find, like the hydrothermal vents and the Atacama Desert. I just learned that there is bacterial life in highly saline solutions.

Those perchlorate salt under rocks, absorbing water vapor from the air and creating a habitable environment. So I think speculation at this point, something that we should really look more carefully. Well, I'm keeping my fingers crossed, which is something people have heard me say before about this possibility. An increasing, I will even say likelihood, that we may find some biological activity on this formerly dead planet. You presented this paper on behalf of dozens of colleagues on the team just a few days ago at the Lunar and Planetary Science Conference. How was it received?

Very well received. I was surprised that the room had, I heard, 500 people seated and the hallways were completely packed with people standing, and no one challenged any of my assertions there. So I was a little surprised. I expected at least some debate, and it looks like everyone agreed with what I said. Peter Smith told us there would be some nice revelations at LPSC this year, but many more to come over the next few years. Do you agree with that?

Are we looking forward? I agree, of course. The more we look at the data, the more we really understand everything that we are seeing, and I think it's a unique place, and the fact that, theoretically, you could predict that liquid water is possible there.

We saw a bunch of hints. We found out this salt, the perchlorates, that are really powerful antifreeze, and the ice was so close to the surface. And besides that, there is layered ice. It's hard to explain how it formed except for by the melting by those brines and all this together I think tell us that we land in a wonderful place and that

as we look at the data more carefully I think there will be more surprise probably Thank you for some very exciting work on this You are very welcome We will once again refer our listeners to planetary.org slash radio where we'll have the link

to the University of Michigan webpage that actually shows these little droplets of water and where you can read a little bit more about this work. The finding of liquid water on the surface of Mars by a team led by our guest, Professor

Nilton Reno, who is a professor of atmospheric, oceanic, and space studies at the University of Michigan Ann Arbor. Thanks again, Dr. Renaud. Thank you very much, Matt. We'll be back with Bruce Betts for this week's helping of What's Up? A Look at the Night Sky. That'll be right after we visit with Emily. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, how come there are sometimes seven days and sometimes eight days between the phases of the moon?

Those of you who are well-versed in how the sky works may be surprised to hear that most people aren't familiar enough with the sky to know that the moon takes more than four weeks, but less than one month to go through its regular cycle of phases. In fact, many people don't even realize that the moon is frequently visible during the day. Our moon takes a little more than 27 days to complete one elliptical orbit around Earth. However, because Earth advances in its own orbit around the Sun during that time, it actually takes two more days for the lunar phases to catch up with Earth's orbital travel. So a full cycle of lunar phases is 29.5 days long, which is a bit longer than four weeks. So if the full moon falls on a Monday, the next

full moon will fall on a Wednesday or Thursday. But since 29.5 days is shorter than almost every month, each full moon usually falls one or two calendar days earlier than the full moon on the previous month. Once in a blue moon, there are two full moons per month. In fact, that's the definition of a blue moon. So blue moons always fall on the 30th or 31st day of a month. The full cycle of lunar phases actually measures one full lunar day from sunrise to sunrise. So for any point on the moon, the sun is above the horizon for nearly 15 days and below it for the next 15, meaning that the

diurnal temperature range is 300 degrees Celsius. You'd better have good heating and air conditioning if you plan to live on the moon. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Time for What's Up on Planetary Radio. Bruce Betts is the director of projects for the Planetary Society. He's here to tell us about the night sky and talk about other things. Welcome. Thank you very much. I got to tell one more story about Nilton Reno, our guest today.

We kept talking a little bit after I stopped recording, and I asked him more about the reaction he's gotten to this. And he said that he's from Brazil, and I guess he was doing an interview with some reporter or host in Brazil and the person broke down it was in tears you know thanking him for this this wonderful discovery even even though not everybody is in full agreement with these results yet it's true the way the the cautious scientific community works there's still cautious scientific skepticism, but it certainly is a tantalizingly interesting result. Maybe it's actually tears.

I mean, that's a salty water. Marching tears. Maybe all this is related. Well, maybe Phoenix landed on somebody, hurt their foot, and now they were crying. Maybe. Maybe that was it. How about the night sky? Well, you can see Mars if you want to. If you get up in the pre-dawn and look over in the east, very low down, there'll be this reddish dot. That's Mars.

Still a little tough, but it's pretty visible. Much easier is if you just look up a little bit in the east, and the extremely bright star-like object is Jupiter. You also might catch low down Venus, which is going to keep getting higher. All of these objects are going to get higher up over the coming days and weeks. But Venus, even brighter object, very low. In the evening sky, we've got Saturn. but Venus, even brighter object, very low. In the evening sky, we've got Saturn.

Saturn up by the time the sun sets in the east, high in the sky in the evening, and it is in Leo. And I encourage you to get your little star chart out, and if you haven't mapped Leo, it's one of the few constellations I can almost buy that I can connect the dots and see a lion. And in this case, you can also see Saturn as some type of, I don't know, firefly flying around a lion. And in this case, you can also see Saturn as some type of, I don't know,

firefly flying around the lion. Anyway, check them out. If you've got a small telescope, check out Saturn. Rings nearly edge on right at this moment. On to this week in space history. 1973, Pioneer 11 was launched. Pioneer 11, with its sister craft, headed out towards Jupiter and Saturn, and then headed off and leaving the solar system. And still going. And I don't know what's happening with the Anomaly, but I guess that's something that the Society's still working on, right? Anomaly.

Ba-dee-dee-dee-dee. It is. It is indeed. We're still supporting the work of Slava Turashev and John Anderson and others. Figuring out this gradual, the fact that Pioneer 10 and 11 are slowing down a little tiny bit more than we expect them to be. They're getting close. They've saved a lot of data, a lot of old data on tapes, been doing a lot of thermal modeling, and hopefully in the next few months we'll have some good interesting results to share. Good, good. We'll look forward to that. On to random space fact. Now there's a departure. I thought we needed something different. Yeah, you haven't done anything like that ever in six and a half years. Give it to us again.

Second take. Random space fact. Okay. Now we can move on. Last week, mere days ago, there were 13 people in orbit. 13. Oh, my. Seven on the shuttle or the shuttle crew, three on the space station,

and three headed to the space station on a Soyuz. This feat has only been matched once before in 1995 with a similar configuration, but the space station was Mir, not the International Space Station. That's wonderful. Thank you. That makes me feel good about us, humanity that is. I'm glad. I'm glad. That's really what I strive for. Let us go on to the trivia question, shall we? We asked you, who was the first person to get married in space?

That person in space, their spouse on the Earth. How'd we do? This is so interesting. We got lots of correct answers. You can find anything nowadays on the web, of course. But a couple of people said Richard Branson, Mr. Virgin Galactic and Virgin fill in the blank. No, he's never been to space, at least not yet.org determined to be this week's winner is Russ Black. Russ Black, a first-time winner, I believe, in Shoreline, Washington, up there in the northwest of the United States. And he said it was Yuri Malachenko. Yuri Malachenko, who was apparently the commander of ISS Mission 7.

And do you know who he married? He married Ekaterina Dmitrieva. Yeah, and she was in Texas, married he married e katarina dimitrieva yeah and she was in texas and he was in new zealand well he was over new zealand true true enough russ wonders if maybe there was a distance record there as well for uh furthest apart during nuptials uh it's possible at least in terms of physical distance. Yeah, exactly. Yes, this was in 2003. So let's go to a completely different direction. And now for something completely different. The Space Shuttle Enterprise was used only for glide tests early in the shuttle program before the space launches of the other shuttles.

shuttle program before the space launches of the other shuttles. What noticeable item did it use during its first glide tests, but not later ones? Go to planetary.org slash radio to get us your answer. I know one because I was there for some of these approach and landing tests. But mom's the word. You're so cool. And it was not your mom. You've got till April 6th, Monday, April 6th at 2 p.m. Pacific time to get us the answer to this latest space trivia question. And you'll win a T-shirt. And I think people were ready for T-shirts again because, boy, the number of question answerers is way up again.

So we're sending them out while they're hot. All right, everybody. Go out there. Look up to the night sky and think about Kurds and way. Thank you and good night. No way, man. He's Bruce Betts, the director of projects for the Planetary Society. He joins us every week here for What's Up.

Join us next time as we learn about the next generation spacesuit that will take American astronauts back to the moon. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Thank you.