Planetary Radio: Space Exploration, Astronomy and Science - The Caves of Mars and the Geysers of Enceladus

Episode Date: November 23, 2009

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The Caves of 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. Could these be the sites of future Mars bases? Why stop there? How about Mars colonies? We'll talk to Glenn Cushing of the U.S. Geological Survey about his discovery of what appear to be huge lava tube caves on the Red Planet. Bill Nye will be back with his regular commentary later today, and then we'll pay a visit to Bruce Betts,

our oracle for where to look in the night sky for wandering stars and other phenomena. He'll also give away another Cosmos 1 solar sail team jacket. Space shuttle Atlantis is still docked with the International Space Station, as I record this, and Mars Exploration Rover Spirit appears to be making a wee bit of progress as it attempts to free itself from that Martian sand trap. And now, something you really must see to believe. Prepare to be amazed. The Cassini spacecraft's second flyby this month of Saturn's moon Enceladus

has returned some of the most beautiful, utterly jaw-dropping images ever taken in our solar system. You'll find them in Emily Lakdawalla's blog entries for November 21 and 22. We've got direct links at planetary.org slash radio. We'll forego Q&A once again this week so that we can talk with the Planetary Society's Science and Technology Coordinator about these pictures that reveal a fantastic terrain dotted with geysers that make Yellowstone Park's Old Faithful look like a dribbling garden hose. Emily, I think you had just the right word for these great images. Wow. Wow, yes, that's pretty much the best I could come up with. Wow. Now, you're on the road, so you did not put these together, but this was work by other amateurs?

That's right. You know, the images for Cassini, like the Mars Exploration rovers, are placed on the Internet for everybody to see. So the original credit for the data goes to NASA and JPL and the Cassini imaging team at the Space Science Institute. But then anybody can play with them. So a couple of amateurs picked up some of the photos and made some mosaics. then anybody can play with them. So a couple of amateurs picked up some of the photos and made some mosaics. And what are even cooler are some cross-eyed stereo anaglyphs, 3D views of the Enceladon landscape that all you have to do to get the 3D to pop is to stare at the computer screen and cross your eyes. And it works quite well. And in one of those, of course, we can see these plumes

rising directly out of the surface of Enceladus. Yeah, you know, this is a photo I never imagined I would see. In the past, Cassini has taken beautiful pictures of Enceladus' South Pole, has taken beautiful pictures of the plumes, but it's very difficult to get an exposure setting on the camera that can see both of them at the same time. And we see in this picture the skinny crescent of Enceladus. The sun is about to set there for the winter on the South Pole. And you see the plumes actually issuing from the night side of the Enceladon South Pole. It is an absolutely stunning image. There is another image, not stereo, but it's sewn together from four others. And I just, I sat and stared at this

incredible surface of this amazing little moon. Yeah, you know, Enceladus, it's actually, it shares something with Europa, in that the two moons, from a distance, they're very smooth. They're almost cue ball shaped. But when you zoom in way up close, their topography is extremely rugged. There's very steep slopes in these narrow, knife-like canyons that cut across the landscape. It's all very fresh geology, and it would be fascinating to investigate up close. You have a couple of other things going on.

One in particular, you're showing people how they can create images like this on their own. That's right. You know, with more and more of these images coming out on the Internet, image processing is getting very democratic. Basically, anybody who wants to can pluck these raw images off the website and process them and make gorgeous views of all these landscapes across the solar system. So I decided to offer some classes to people on how to do just that. You can get the information on where to download those classes on the blog. this little news update from you, Emily, instead of Q&A. But it occurred to us that we might want to ask you folks, the listeners,

whether you like these little live reports or conversations with Emily, maybe to the point where we would start doing this instead of her Q&A. We know how much you are crazy about Q&A, but what we'd like is for you guys to let us know. You can do that by writing to planetaryradio at planetary.org. Let us know what you think, Q&A or a live conversation with Emily as a regular part of Planetary Radio. Emily, thanks a lot for joining us. Thanks for having me, Matt. Back to Mars now.

Glenn Cushing is a physicist surrounded by the geologists who staff the United States Geological Survey's Astrogeology Science Center in Flagstaff, Arizona. Glenn announced a pretty exciting discovery in October, long grooves on the side of a Martian volcano that appear to be lava tubes, really big lava tubes. Some are more than 100 kilometers long and 150 meters wide. Here and there, the tubes appear to be punctured by openings or skylights, collapsed areas that may be related to the seven holes or pits a USGS team found in 2007 and subsequently named the Seven Sisters. I called Glenn Cushing at his office a few days ago. Glenn, I am just really thrilled to have you back to talk about this topic. Do you know that it was

two and a half years ago that you were last on with some of your colleagues there at the USGS, and we talked about these so-called Seven Sisters? What is new in this recent announcement? Well, now we're looking at actual cave entrances. With the Seven Sisters, we have some really deep holes into the surface, and we are suspecting that there might be caves extending laterally beneath them. With things we found now are more actual cave entrances into the surface, some of them going into lava tubes and others going into volcano tectonic fractures that probably go deep beneath the surface. Remind us of what a lava tube is and how these form,

or at least how we've seen them form on our own planet. Well, typically lava tubes are, they're transport mechanisms when you have low viscosity lava flowing across a shallow sloped surface. These essentially are channels of lava whose roof becomes encrusted as the surface material cools. Then we have an enclosed pathway for the lava to travel, so it can go great distances away from its source vent without cooling off. And that way lava can be distributed for long distances across a lava flow.

And then when the source of this lava becomes either diverted or exhausted, then the rest of the lava within the tube often just kind of drains away and leaves an open space. This leaves a long, twisty tube that's usually completely enclosed and sometimes has skylight openings where parts of the material might have collapsed down through it. So you're just left with a long, tubular cave that stays near the surface instead of diving deep beneath. How would you compare these suspected lava tubes on Mars with the ones found on Earth? We assume they're quite similar.

What we usually see on Mars in terms of volcanism are mafic type of flows, which are more like basalt, very similar to the basalt flows we see on Earth, such as coming out of Hawaii right now. flows we see on Earth, such as coming out of Hawaii right now. And we generally consider the volcanism on Mars to be fairly analogous to the basaltic volcanism that happens on Earth. Except that these are apparently, I mean, they're huge. Some of these are. We kind of expect structures to be able to reach larger sizes on Mars in the lower gravity. So the strength it requires to hold up a certain amount of mass, such as a ceiling, is going to be the same for different depths of rock. But with less gravity pulling down on it, it can actually hold a greater amount of mass above it.

I was thinking when the phrase the caves of Mars went through my mind, I thought, my goodness, what a great title for a science fiction novel. Actually, that is the title of a science fiction novel. You know, I found that it's in some children's series. Is that the one you're thinking of? I think it might be. Actually, I have it kind of sitting as a decoration in my office right here. That's good. Well, you had to get that. Yeah, it's one of those nice kind of cool, cheesy vintage covers on it. What instruments did you use to discover these? The first instrument to observe these was the Themis visible wavelength camera, which is on the Mars Odyssey spacecraft. It observes at resolutions down to about 18 meters per pixel. So we were able to kind of find the

channel-like areas that these skylight entrances occur in at fairly low resolution for what we're looking at. We were able to see some kind of dark holes along these channels. And then we acquired some images from the context camera, which is Mars Reconnaissance Orbiter. And this observes down to resolutions of about six meters per pixel. And we could get a much clearer idea of what was actually happening. Now we're awaiting high-rise observations. It's the super high-resolution camera that's on the Mars Reconnaissance Orbiter. This will observe the surface down to about 25 centimeters per pixel,

so about 5,000 of those pixels can fit into one Themis pixel, and we can get just wonderful resolution. We only have one of these super high-resolution images so far, and we're just awaiting our turn in line, really, to get the next observations. Yeah, that is one powerful and popular instrument. We've talked about it frequently on this show, pretty incredible. We'll put up that already-acquired HiRISE instrument at planetary.org slash radio, where we'll also have links to the press release regarding this discovery. How much would you love to see a rover crawl into one of these?

That would be absolutely amazing, though I suppose I'd be surprised if it actually happened in my lifetime. There's a lot of hurdles to overcome before that's possible. Well, first of all, we need to develop precision landing technology for one thing. Right now, the spacecraft that go to the surface now are targeted to land within an ellipse that's several kilometers long, to land within an ellipse that's several kilometers long. And hitting such a specific target would be pretty tough to do right now, especially since the features we've found thus far are at kind of a high elevation on Mars, so there's less atmosphere for a spacecraft to maneuver in to reach these sites.

Another important bit that we have to address is the issue of contamination. Right now there are planetary protection policies in place that basically forbid any of our robotic or human spacecraft or explorers to go into certain areas on Mars where we think that any type of astrobiological activity might be present. So whether it's past or present evidence of whether any microorganisms ever existed there, we need to be very careful about contaminating that with anything that we bring, or if it's a returning mission, anything that we might be bringing back. So, yeah, a few significant hurdles to overcome before we can actually go there and visit, unfortunately. That's Glenn Cushion of the U.S. Geological Survey. He'll be back to tell us more about the discovery of giant lava tubes on Mars when Planetary Radio continues. Hey, Bill Nye the Science Guy here. I hope you're enjoying

Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era. Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J, the passion, beauty, and joy of space exploration. You probably do too, or you wouldn't be listening. Of course, you can do more than just listen. You can become part of the action, helping us fly solar sails, discover new planets, and search for extraterrestrial intelligence and life elsewhere in the universe. Here's how to find out more. 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

t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. Glenn Cushing is a physicist with the U.S. Geological Survey's Astrogeology Center. He discovered the so-called collapsed depressions on Mars that indicate the presence of long, wide lava tubes or caves. They're on the side of a volcano called Arsia Mons. Glenn was telling us before the break that there are many challenges that must be met before even robots can explore these tubes.

many challenges that must be met before even robots can explore these tubes. One is making sure we adequately protect evidence of past or present life. Is there reason to believe that there might be more opportunity to find evidence of biological activity in these caves than out there in the open sun? than out there in the open sun? Well, cave environments can effectively protect anything that's inside of it from very dangerous conditions that are on the surface. On Mars, we have just about zero magnetic field and very thin atmospheres on Earth that moderate or deflect a lot of hazards coming from space, such as micrometeoroid bombardments, a lot of radiation coming from the sun in the form of ultraviolet light and alpha particles,

high-energy cosmic rays, lots of things going on on the surface. There's also kind of intense dust storms and high-temperature variations. And being inside of a cave, you're kind of protected from all those things that go on at the surface. We have no reason to believe that there is any microbiology going on on Mars at the moment. But if there is or ever has been, then caves might be some of the only places that we can access on Mars that are capable of preserving that evidence. Well, let's talk about the Martians to come, us. And you've speculated on how these caves might protect us pretty well as well. Well, if we do go to visit Mars, especially if we're going to spend

any considerable amount of time there, we would have to, if we didn't go into caves, we would have to if we didn't go into caves we would have to either engineer and transport some kind of substantial shelter or we would have to build it in place and both of those options seem like they would be rather prohibitive in the amount of energy expenditure that would be required or even the time it would take to do those things and if we move if we can go into caves that are already there, then the payloads could go towards more scientific instruments, more supplies, more people,

and it would just very well be a lot more easy and a lot more cost-effective to use caves. And there's even been some speculation that lava tube caves in particular, since they're just kind of these long tunnels, that they might be sealed along their walls and at each end and then pressurized for sort of a long term. You could even have a community in something like that. Wow. You know what? That reminds me of a short story. No, it was a book by Robert Heinlein where they did something like that on the moon.

Heinlein where they did something like that on the moon. I think it was, I can't remember the name of the story, but it's the one where they fly around inside a giant bubble underneath the surface. Absolutely fascinating. And one of the things that I found amusing is that in some of the commentary that I saw about this, people were saying, oh, well, we can't just have people moving into caves until we discover that they're not going to collapse. I mean, these things have been there for how long? Well, probably quite a long time. The area that we found these in is actually a fairly young place on Mars, geologically speaking, but that means it's at least in the tens of millions of years. We can't say for sure at this time, especially not before we get much higher resolution data coming through,

but we can't really say when these entrances formed in relation to when the rest of the area formed. There's a possibility that they have collapsed in the not too distant future when the tunnels were there all along, or they may have formed when the tunnels were active. And we might be able to tell the difference between those ages once we can see what's going on on the floor beneath these skylights. If there's a big pile of rubble from the collapsed ceiling material, then it formed after the lava activity. But sometimes on Earth you can look down into a lava tube skylight and see kind of a smooth floor of cooled lava. So you can say if there's not that pile of rubble sitting at the bottom, then the skylight must have formed while lava was flowing, and the stuff just got carried away. Glenn, we're about out of time.

When do you hope to get those high-res images from HiRISE? Hopefully early next year. I think, if I'm not mistaken, HiRISE has been in safe mode recently, and they're trying to really preserve the spacecraft and make sure they get everything right before they start observing again. And they also need to kind of save it for what's going to be a data relay instrument when the next rover goes to Mars. So they want to make sure it's alive at that point.

Yes, let's hope so. And I'm also thinking some talented artist out there listening to this show ought to get in touch with you and come up with a nice rendering of a Mars colony inside one of these lava tubes, a nice long linear colony in a lava tube underneath the surface of Mars. Yeah, that'd be pretty cool. Glenn, thanks so much for joining us once again on the show. Thanks a lot, Matt. It's great to be back. Glenn Cushing is a physicist working with a whole bunch of geologists at the USGS, the United States Geological Survey,

specifically the Astrogeology Science Center in Arizona, the American Southwest. We've been talking about this very exciting discovery of what appear to be lava tubes, big ones, on the side of a volcano on the red planet. And we'll talk about what else is going on in the solar system in just a few seconds when we visit with Bruce Betts for this week's edition of What's Up. Hey, hey, Bill Nye the Planetary Guy here, Vice President of the Planetary Society. And among my many faults is this desire for everyone to be happy. Let me tell you something. If you try to please everyone, you're going to make somebody unhappy. So look, they found ice on the moon. Tiny, tiny, tiny amounts of water. Unbelievably

small amounts of water. Like some parts of the moon, this part that's wet, it's drier than the Antarctic deserts. So let's not get our hopes up, everybody. We're not going to go to the moon with a nuclear reactor and set up camp and melt the lunar ice and have greenhouses and convert the lunar regolith into food. It's just not going to happen. If you want to do that kind of exploration, looking for these hydroxyl groups, these would be some sort of hydrogen ions that come off the solar wind and interact with the regolith in some way to make OH groups of atoms that can become HOH, which we call H2O, which we call water.

I mean, that's all good. But it's just not going to happen tomorrow, everybody. Don't get your hopes up. The Atlanta Space Shuttle is on orbit right now, taking up, I guess it's 15 tons of stuff for the International Space Station, and that's good, but it's time to retire the shuttle. If you want to do more exploration of the lunar regolith, let's do it with some robots, because the next destination for people, the next destination for humans, has got to be beyond lunar exploration.

I know this is upsetting to some of you. That's just how it goes. Not everyone's going to be happy when it comes to lunar exploration and the spending of tax dollars on the exploration of space. Now let's move forward, people. The Ares rocket, the invention of the year. It's in the English system. It's not even metric. We're going to

continue to explore the moon with robots. We're going to continue to explore Mars with robots so that people can go there someday and, dare I say it, change the world. I gotta fly. Bill Nye the Planetary Guy. We've got Bruce Betts on the Skype connection. Lots of Skype today. Boy, what a nice service. He is the director of projects for the Planetary Society, and it must be time for What's Up. How are you doing? Well, you know, Skype should be free for us, considering how much we promote it. We do, actually. And I meant to contact them at one point and say, you know, you guys want to underwrite the show or something, but never got around to it. Hey, well, if you guys are listening, feel free to send us money.

And they are listening. They're always listening. So in the night sky in the evening, we've got Jupiter bright, brightest star-like object up there over in the west. Can't miss it. In the pre-dawn sky, Venus pretty much gone. But if you can see it, it's awfully bright.

But Saturn looking yellowish and like a kind of bright star. Bright star. We'll go with that. About halfway up above the eastern horizon. Mars getting exciting. Rising in the east in the mid-evening up in the pre-dawn. And it will continue to get brighter through its opposition at the end of January, and we'll keep you posted. It's starting to get quite bright and reddish. A little note, just to get us ahead of schedule, we've got the Geminid meteor shower. Make your plans now. December 14th, peaking. Traditionally best consistent meteor shower of the year. Let us go on to this week in space history.

Had some Mars stuff happen. Mars 2 in 1971 becomes the first artificial object to hit Mars. That was a Soviet probe. That was a Soviet probe. It hit it. Didn't give us much else, but it did hit it, presumably. But we also had the launch of Mariner 4 in 1964, the first successful flyby mission of Mars to return data. And we also had this week, 40 years ago, 1969,

Apollo 12 returned to Earth, which leads me to Random Space Fact! That's kind of a Star Wars-y thing. George Lucas would have liked that. Random space fact! What was that? That's kind of a Star Wars-y thing. George Lucas would have liked that. And I'm sure he's listening. Apollo 12 did the spiffy thing and landed within 200 meters of the Surveyor 3 robotic space probe, went over, ripped pieces off for analysis back on Earth, and then had to sell them at a spacecraft junk sale because eBay had not been embedded yet. Really?

They vandalized a probe. Exactly. They did leave it on blocks, oddly enough. Yeah, right. That's what the Martians are going to do to the rovers, you know. That's probably spirit's problem let's find them someday up on blocks wheels gone damn martian teens get out of here you kids get away from our rover all right on to a trivia contest and and we asked you, in the context of naming objects out there in space,

and people gave us, I know, some other ideas that NGC is used for in the space world, but we were talking about naming things like galaxies and clusters. What does NGC stand for? How do we do, Matt? You know, we're going to have to stop giving away such good prizes, because we set another record this time for the number of responses pencil this week yeah i think we should really out of all of these almost everybody got it correct we got some odd ones yes which i will tell you about but let me tell you the winner first of all it was angel stoichev angel stoichev who lives get this in gabrovo bulgaria who said, NGC, the new general catalog.

Very nice. Congratulations. And I guess it contains 7,840 objects. And we can thank J.L.E. Dreyer for putting it together back in the 1880s. Want to hear a couple of funny ones? Ken Brenneman, he got it right. Ken said new general catalog. Or could it be the Nevada Gaming Commission?

You know, I was thinking of that. But here's my favorite, Tom Burns, who is convinced that Random.org doesn't like him. So he believes that NGC stands for Not Going to Count. Sorry, Tom. Maybe next time. Yeah, that one I had not thought of. Speaking of next time. Hey, what are we going to give away next time?

How about another huggable Mars? Oh, I love the hug of Mars. My kids love the hug of Mars. All the world loves hug of Mars. To win a hug of Mars, answer the following question and get selected by random.org. The question is, of the moons in the solar system, the natural satellites of planets, which one has

the highest density? Or which ones? Within our error bars, highest density moon in the solar system, go to planetary.org slash radio, find out how to enter. You've got until Monday, November 30th at 2 p.m. Pacific time to get us that answer.

All right, everybody, go out there, look up at the night sky and think about, well, it'll be hard because it's nighttime, but think about sunlight filtering through the leaves of a beautiful tree over your head. You know, I was just taking a walk with a wife and we stopped to do exactly that. One of those few trees in California that you get a little fall color from. Those of you who have fall color everywhere, we're insanely jealous, but thanks for listening to another edition of What's Up with Bruce Betts, the Director of Projects for the Planetary Society. He does join us every week for this segment.

Don't forget to tell us which you prefer, Emily's Q&A feature or a quick conversation with her about the story of the week. Write to planetaryradio at planetary.org. Planetary Radio is produced by the Planetary Society in Pasadena, California. Keep looking up. Thank you.