Planetary Radio: Space Exploration, Astronomy and Science - Europa: Life Beneath the Ice?

Episode Date: March 6, 2006

Highlights from a public forum on what may be found in Europa's ocean and how to reach it, w/ Chris McKay, Bob Pappalardo, Torrence Johnson, and more.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

The Lively Ocean of Europa, this week on a special edition of Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. On Sunday, February 26, more than a hundred people gathered to hear scientists talk about why a mission to one of Jupiter's moons is one of the highest priorities in all of planetary science. We'll hear highlights from the discussion on today's program. Emily Lakdawalla's Q&A segment will return next week, but we'll still have time to visit with Bruce Betts for another What's Up look at the night sky

and another chance to win an Explorer's Guide to Mars poster. There's still good reason to check in with Emily if you want the inside scoop on NASA's cancellation last week of the Dawn mission to asteroids Vesta and Ceres. She interviews mission co-investigator and Planetary Science Institute director Mark Sykes. You'll find her blog at planetary.org. The worldwide space agencies contributing to the International Space Station have reaffirmed their commitment to finishing the ISS. A reconfiguration will require 16 more space shuttle flights,

resulting in a station that can support nine permanent crew members. Unfortunately, it also means there will be little or no time for science on those shuttle missions. Asteroid impacts present and long past are also in our news. 2004 VD-17. That's the rock just given a score of two on the Torino scale by the Jet Propulsion Lab's Near-Earth Object Program. JPL says there is a 1 in 1,400 chance that the 500-meter threat will impact our planet in about 100 years. That collision would have the energy of about 15 billion tons of TNT,

or more than all the world's store of nukes combined. And speaking of big bangs, planetary scientist Farouk Elbaz thinks he has found the remnants of one that happened ages ago in the Sahara Desert. The 30-mile-wide crater may explain the pieces of yellow-green glass found in the region for more than 70 years. There's more about both of these stories at planetary.org. Hello and good evening and welcome to a night of Europa, an interesting night it promises to be.

I'm Bruce Betts, the Director of Projects for the Planetary Society, and we're here presenting this event along with the NASA Astrobiology Institute Europa Focus Group. NAI has been incredibly helpful in helping us get all of this set up and handling logistics locally here, bringing together many of the world's Europa experts, Europans, all hanging out talking about Europa science, Europa missions and such. So this is our way of trying to share that out with the public. Yes, that was our man Bruce, the Master of Ceremonies last week at NASA's Ames Research Center. The public event preceded a couple of

days of professional presentations and discussion focused on that ball of ice, water, and iron circling our solar system's biggest planet. Of course, it's the water that has everyone excited and terribly curious. A world encircling ocean under kilometers of ice, perpetually dark, but far from cold, and possibly containing all the other elements needed to support life. But is anyone there? The overall message of the evening was, we won't know till we go.

Bob Pappalardo is a professor in the University of Colorado at Boulder's Laboratory for Atmospheric and Space Physics. He also spent the last ten years studying Europa. Pappalardo began by looking back to the discoverer of the moon. Galileo realized the object in his telescope was not another star or planet, but a satellite circling Jupiter, along with the three other Galilean moons. And by doing so, changed our sense of place in the universe. No longer was the Earth the center of the universe, but instead, with the discovery that Jupiter was its own center of motion,

with moons going around it, it was seen that there could be other centers of motion with moons going around it, it was seen that there could be other centers of motion. And Earth was one of the worlds going about our sun, and the moon was going about the Earth. It really changed our sense of place in the universe. If we find that Europa has a subsurface ocean, and if that ocean has life within it, it could again change our sense of place in the universe. So Europa is telling its story if we're smart enough to follow along. Pappalardo went on to document the impressive list of conclusions about Europa that have convinced scientists of the existence of the ocean below the surface ice.

If Europa's ice shell were locked to the interior, the stresses would be very small. But if there's an ocean down there, the ice shell can bulge more as Europa orbits around Jupiter and create great enough stresses to form these fractures. There are very few impact craters on Europa. And then there are two of these things that don't look like craters at all. They have rings around them, and they sort of have a flat center to them. What might have happened is that an impact came along that was big enough to penetrate right through Europa's ice shell about 20 kilometers thick. 20 kilometers deep is how deep these impact craters penetrated.

And then as the ice moved in to fill that hole, it broke along fractures concentric to the impact site. So that would imply an ice shell about 20 kilometers thick. If you want to study an ocean, it makes sense to involve an oceanographer. That would be John Delaney, professor of oceanography at the University of Washington. John spends much of his time deep under our own oceans in the Alvin submersible. He's also behind the Neptune program, which hopes to construct a real-time network of thousands of intelligent sensors on and under the sea. You can't help wonder when you're on the seafloor whether or not something like what you look out the window and see

is similar to what actually exists on the floor of the ocean of Europa. The oceans are central to life on Earth. There's no question about that. Without them, we would not be sitting here. I wanted to actually suggest that perhaps at this juncture in the evolution of the planetary society that you have an ocean chapter, that there be a subcomponent of Planetary Society that actually is a sort of an ocean freak.

It would be really kind of fun to do that. They are mysterious, fortunately. They are dangerous, in fact, as we've found over the past year, and they are unexplored. We must learn to understand the oceans completely, as much as we can, to understand planetary and local ecosystems. This is very, very important. There are bold new approaches, I mentioned this, to studying the oceans on Earth,

and hopefully these approaches will revolutionize the way that humans interact with remote areas of oceans on the earth as well, hopefully, and in long term beyond the earth. And here's a discovery that's going on right now. The idea that when volcanoes erupt on the seafloor, when we get there, even if it's months later, we find that massive amounts of microbial material are coming out of the seafloor where these things have happened. find that massive amounts of microbial material are coming out of the seafloor where these things have happened.

I mean, I'm talking tons and tons and tons of material on an hourly basis coming out of the seafloor, and it lasts for months. In 11 out of 11 cases that's happened, we conclude that there is a microbial biosphere of heat-loving microbes that lives within the rocks below the seafloor. The microbes basically dine on volcanic gas, and they live at temperatures close to 100 degrees centigrade. If a deep, hot biosphere of that type exists on this planet, could it be on other planets? Well, my argument to you is that by designing innovative strategies

to explore the linkages among volcanoes and earthquakes on Earth, we gain essential knowledge about key processes on our own planet. We also obtain critical new insights about how to explore for life on other planets. And the bottom line is, if you want to slightly whimsically, there's not much known about what's left to be discovered. Thank you. We'll hear more from John Delaney in an upcoming episode of Planetary Radio. Thank you. Now he is chief scientist for the Solar System Exploration Programs Directorate at JPL. Torrance doesn't just believe we should go to Europa.

He says we can do it now with existing technology. The most recent major survey of the entire planetary science community recommended a Europa orbiter as the highest priority new flagship mission, and they established a number of goals for it, which are fairly obvious if you've been interested in Europa. You want to find out whether that ocean is really there. You want to find out how deep beneath the ice it is. You want to characterize what's going on.

You want to see whether the water has been coming up to the surface recently. You want to take the type of data that would prepare you for the next stage of exploration, just like we're doing on Mars now. Okay, bottom line is with enough mass for shielding, a Europa mission can be done now with current technology that will last long enough to really do an exciting mission at Jupiter and at Europa. We put approximately a three-ton spacecraft with ten science instruments together. The Radhart electronics I just described would give you about a two-year science mission in the Jupiter system. We want to convince you, convince our colleagues, and hopefully even

convince NASA that we'd like to remove these question marks from Europa planning, extending to a return to Europa sometime in the next decade. But why look for life at all? And how will we recognize it if it is like nothing we have seen on Earth? Stay tuned for good answers from planetary scientist and astrobiologist Chris McKay. This is Buzz Aldrin. When I walked on the moon, I knew it was just the beginning of humankind's great adventure in the solar system. That's why I'm a member of the Planetary Society, the world's largest space interest group. The Planetary Society is helping to explore Mars.

We're tracking near-Earth asteroids and comets. We sponsor the search for life on other worlds, and we're building the first ever solar sail. We didn't just build it. We attempted to put that first solar sail in orbit, and we're going to try again. You can read about all our exciting projects and get the latest space exploration news in depth at the Society's exciting and informative website, planetary.org. You can

also preview our full-color magazine, The Planetary Report. It's just one of our many member benefits. Want to learn more? Call us at 1-877-PLANETS. That's toll-free, 1-877-752-6387. The Planetary Society. Exploring new worlds. Welcome back to a special edition of Planetary Radio.

We're offering, for your enjoyment, highlights from a recent public event at NASA's Ames Research Center near San Jose, California. The Planetary Society and NASA's Astrobiology Institute brought together some of our planet's most distinguished experts on Jupiter's moon Europa, which just might be the most likely place to find life in our solar system beyond our own lively planet. Chris McKay may have been the only participant who didn't have to fly into the event. He's a researcher at Ames and a member of the Astrobiology Institute. He has looked for life everywhere from Antarctica to Mars, and he is especially excited about what might be swimming under Europa's ice. Chris will be making an extended appearance on an upcoming edition of Planetary Radio. In the meantime, here are a few minutes of what he shared at the February 26 event.

Why is life on other worlds interesting? What are we hoping to find on Europa? What we're hoping to find on Europa is the possibility that there's a separate type of life there, the second genesis of life. That's what astrobiology would really like to find, life not as we know it, life different from the life we have on Earth. And why is that interesting? Well, first, from a practical point of view, it would allow us to do comparative biochemistry.

Everything we know about biology, everything we know about biochemistry, is based on studying the one example we have here on Earth. We could study it in incredible detail and not learn what we would learn by having another example to compare it to. So that would be important scientific information. Also, it would tell us that if in our own solar system life started twice, once on Earth and once on Europa, then life is common in the universe. That's really an interesting thing to know, and I put my little editorial comment there.

Yay, that would be great to know that life is common in the universe. We all think that it's true. Some of us seem to have personal private evidence that it's true. But scientifically, we don't have any data to support the notion that life is common in the universe. We'd like to know that. On Earth, life is made of carbon and lives in water. Does that mean all life everywhere in the universe has to be based on carbon and live in liquid water? Well, maybe, maybe not. But we know that that's at least a good place to start. And here in our solar system, we've got two worlds with water. That's the

logical place to look for life first. That's where we're going. Europa is the target. So I want to ask the question, given liquid water, is it plausible that there was an origin of life on Europa, a separate origin, and is there plausible ecology? Is there something for the folks to be eating there on Europa? The current theory that's the most popular in the scientific community, which is that life started as a result of chemical reactions involving hot water and hydrogen and sulfur, just the sort of thing that's coming out of the vents that John Delaney's studying,

that's the most popular theory now for the origin of life on Earth, and that one works well for Europa. So maybe life could have started on Europa. We're on much better ground when we talk about is there food to eat on Europa. On Europa, below the ice in the ocean, there won't be any light, there won't be any oxygen, and there won't be any free food coming from plants at the surface. Do we have any ecosystems on Earth that work without light and without oxygen?

Well, we know of two that work on chemical energy. This reaction is the basis of their biology, is hydrogen plus oxygen going to methane and CO2, and these are just the papers that report that. So we have examples on Earth of ecosystems that are profoundly independent of light and oxygen and don't rely on someone else providing them with food. So could such an ecosystem work on Europa? Yeah, it could.

You could imagine that there's water and CO2 in the ocean. The organisms consume that to form methane, just like the ones in the subsurface on Earth, and then thermal circulation, like what John's reporting on the plate spreading centers on Earth, could process that ocean water, and at temperatures as low as 500 degrees, the hydrogen and the CO2 would be recreated, completing the cycle. This could be a plausible ecosystem for life in the ocean on Europa. We can point to ecosystems on Earth and say we have ecosystems, not just individual bugs, but whole ecosystems that work the same way. So if Europa has an ocean, we're pretty sure it does, if that ocean has life,

it's going to be hard to get to that ocean. As Bob indicated, the ice may be 20 kilometers thick. That's a lot of ice to dig through. But Bob also indicated these features, surface features, that may contain material upwelling through the ice cover. And if so, they may contain biological material that's coming from the ocean, or as one wag put it, frozen fish on the surface, right? Now, we don't expect fish on the ocean of Europa,

but frozen microbial European fish, if you want to think that way. So what we would like to do in astrobiology is get a piece of this brown stuff and taste it, figuratively speaking. Maybe like chocolate. It looks like chocolate to me. Direct analysis of this organic material is what would tell us whether it's biological in origin or not. Next slide, please. Well, what's the question we're asking? Remember, go back to the beginning. What we're asking is, is there a second genesis of life on Europa? And so if it's like us, if it's got DNA, if it's got ATP,

and all the things that we have, it's very easy to detect, but then it's not very interesting. Who wants to fly all the way to Europa to just detect some more microbes when you've got plenty of them right there in your kitchen and bathroom and bedrooms and other places where they shouldn't be? Now, on the other hand, if it's not like us, if it really is alien, if it doesn't have DNA or it's got different, completely different alphabet in its DNA, then we don't know how to detect it at all. None of our methods would detect alien life. That's the hard problem, but that's the interesting one, too. So we're faced with, we hope to be faced with an interesting

problem, which is we go to Europa, we scoop up the brown stuff. It is organic, but we don't know how to analyze to determine if it's biological, and it's not us, right? So how do we detect alien life? Well, the next slide shows the standard approaches in the literature. How do you detect alien life? Well, first, my favorite method, use a tricorder. You all recognize, of course, Episode 26 of the original series, which I'll remind you was Spock's favorite episode, I've heard. Episode 26, where in a few minutes, Spock adjusts the tricorder

so he detects life, not just detects alien life, but detects silicon-based alien life. If we had one of those, the Europa problem would be easy. NASA doesn't know how tricorders work. Not only does NASA not know how tricorders work, even science fiction doesn't know how tricorders work. You've got to know something is mysterious when even science fiction can't explain how it works. I'm not going to wait for that. The other approach, of course, I call the Justice Stuart Potter approach, which is,

we don't know what it is, but we'll know it when we see it. Well, that works if things are big and moving, but it doesn't work if it's microscopic and dead, which is what we expect on the surface of Europa. So how could we do this? What would we do? And this is actually a real question. What would we do with this brown stuff from Europa? We are planning, as you'll hear, missions to Europa. We hope to get some of this brown stuff.

And so NASA is asking its scientists, what are you going to do with it? What kind of instruments will you fly? What will you look for if you want to do a meaningful biological experiment? So I want to propose a suggestion. Next slide, please. Based on the Lego principle. And this is the mundane, everyday observation that biology on Earth is built from a small number of components used over and over again,

just like a Lego block. Think of a Lego block. Take a bunch of identical bricks and stack them up. Well, that's how biology works. The great polymers of biology, the proteins, are made up of 20 amino acids, stack, stack, stack. The nucleic acids, a five-nucleotide basis, and the polysaccharides made up of the D sugars.

It's the Lego principle. Take the same molecule, use it over and over again like a series of building blocks. And I think you can argue that this is likely a common property of biology and mass-produced children's toys throughout the universe. It's the most efficient way to do it. Life is going to follow this principle. So what does this mean practically? It means that if we go to Europa and scoop this brown stuff up,

if the organic molecules there are non-biological, they're being produced by Miller-Urey type synth processes or like the organic material in asteroids or comets or on Titan, then the distribution will be non-biological and it will be smooth. Every kind of molecule will be in there, all sorts of sizes and shapes. It'll be a jumble, like a jumble of rocks on a hill, all different sizes. But if it's biological,

there'll be certain molecules that appear over and over again, and some molecules that are very similar that won't be there at all. Like on Earth, there'll be the L amino acids and none of the D amino acids. There'll be a very statistically unusual distribution. It'll look like a series of delta functions instead of a smooth distribution.

And then we'll know that this something peculiar is selecting certain molecules here enormously over other molecules. This is what we're calling the Lego principle of life on Earth. And hopefully, the molecules that life on Europa is selecting will be so different than the molecules that we use on Earth that we'll be able to say it is really a different type of life, a second Genesis. And we'll know, even if we don't actually have a living example of life, we will know that in that ocean, there's life,

and that life is different from our life and therefore represents a separate genesis, and the universe is full of life, and it's a much more interesting universe than it was before we learned that. NASA scientist Chris McKay, part of a very distinguished panel at NASA's Ames Research Center, examining faraway Europa and the chance for life beneath its ice. I'll be right back with that event's emcee, our own Bruce Betts, in just a moment. Time for What's Up on Planetary Radio. Bruce Betts is here. He's the director of projects for the Planetary Society, and he joins us every week to tell us what's up in the night sky,

which he promises to do this time. We didn't really quite do that last week. Actually, you did talk about some cool stuff. I did talk about cool stuff in the night sky. All I did was didn't do the standard planet report, but they were pretty much where they were last time. And they are again, I bet, this week. They are, but let's tell you where that is. In the evening sky, you can check out Mars high in the sky looking kind of orangish uh in the south after sunset and

you can check out saturn getting pretty darn high as well off in the east after sunset and below castor and pollux and the pre-dawn sky you can see really bright jupiter very high in the sky also you can see it around midnight rising in the east and you can see even brighter venus now getting high enough up you should be able to see it just before dawn in the east. We also have a couple eclipses to mention. The first one, not very spectacular. I mentioned it last week.

I'll mention it again for completeness. On March 14th, there is a penumbral lunar eclipse. Penumbral, penumbral, let's call the whole thing off. And that means that the moon will be moving through part of the Earth's shadow. So if you're on the moon, you would see a partial solar eclipse going on, the Earth crossing in front of part of the sun, but not all of it. What that means is the moon's surface is not dark and all that much. But if you're focused, if you're concentrating, you can see it.

It's March 14th. NASA has a good site on eclipses. You can find information. If you are interested in watching, you can't see it from the west coast of North America, so we won't be seeing it, but you can see it from the rest of North America, from Europe, from Africa, Asia, you'll catch part of it. Now, we have a solar eclipse, which is ultra cool, although only a small part of the world will be able to see it. And that is on Wednesday, March 29th. And the umbral shadow, the complete shadow, total eclipse begins in Brazil, extends across the Atlantic, northern Africa, and central Asia, where it ends at sunset in where you and I will be, western Mongolia.

Covering it live. Okay, maybe not. Again, good information on the web from NASA's site. We'll try to put that. You can link to it from our site at planetary.org slash radio and get more information on that if you are interested in seeing it. The penumbral shadow, which will include parts of Africa, Europe, and Central Asia. Don't we have money in the budget to go to Rio?

Yeah, you want to redirect that to Mongolia? No, I was thinking of Rio. Didn't you say it starts in Brazil? Yeah, but I'm not sure it's right in Rio. But yeah, okay. I thought, yeah, a cruise of the Atlantic is probably the best way to do it, or the Mediterranean. Okay.

All right, I'm going to get the requisition in. What else have you got for us? All right, do that. This week in space history, I'm going to do something that we will be reporting in future years. Kind of a wacky thing. What else have you got for us? not a big deal, but in the last couple decades, we've lost a couple closer to the time than right now in Mars Observer and Mars Climate Orbiter. Hopefully things will go swimmingly with Mars Commissance Orbiter that includes

a big, humongous telescopic camera that will get us the highest resolution images ever, just 15 centimeters per pixel. Also includes an infrared spectrometer, a cool atmospheric instrument that we'll have a lot on our website about. We'll be covering all of this at planetary.org.

You can check it out there, and I'm sure Matt will be telling you about it after the fact. And they heard about the Mars Climate Sounder already. We talked about that on this show. So we have doubly reasons to keep our fingers crossed. We're covering it. If you want more information, you can go back in the archives, too, Keep our fingers crossed. We're covering it.

If you want more information, go back in the archives, too, and check out the Jim Graff, Rich Zurich interview and learn more about Mars Connoisseur Orbiter. Moving us on to Red Bull Space Fact! That was grand. Oh, thank you. Hey, most of the rocks on the moon, most of the youngest rocks on the moon are older than most of the oldest rocks on Earth. There's a little bit of overlap, but not much. So almost all the moon's surface is older than almost basically all of the Earth's surface, except for a few tiny examples that mesh.

Senior member of the planetary system. Yeah, certainly one of the senior surfaces gives us that history of the early solar system. Cool stuff. Okay, contest. Trivia contest. We ask you, what's that semi-ugly name of the area mostly occurring in the state of Washington in the United States that is an analog for giant outflows on Mars, where on Earth at the end of the last ice age you had ice-covered lakes, the ice broke, massive amounts of water flooded out, ripped up the basalts.

How do we do, Matt? What's it called? It does have a gross name, and we got lots of people who live in that region and actually thanked us for giving it some attention despite its ugly name the channeled scablands it's a beautiful area with an ugly name this channel scablands don't don't pick it alan dietrich a long time listener to the show alan dietrich of british columbia qualicum beach british columbia is uh the guy who uh who got through with the correct answer this time and was randomly chosen as our winner. So, Alan, congratulations, and he's going to get an Explorer's Guide to Mars poster.

Spiffy keen. Let's go and give another person a chance, and we've got this question. The Apollo 12 astronauts, when they went to the moon, they visited a human-made object that was already there. What object was that? Apollo 12, what human-made object did they visit on the moon that was already there? Get your answer to us by March 13. March 13 at 2 p.m. Pacific time, and we'll make sure you're part of the contest. Okay, everybody, go out there, look up in the night sky, and think about the utility of shoeboxes.

Thank you, and good night. I love shoeboxes. They're so good for just about anything. Apollo 12 didn't find a shoebox, did they? We'll find out later. He's Bruce Betts. He's the director of projects for the Planetary Society, and he joins us every week here for What's Up. the Director of Projects for the Planetary Society, and he joins us every week here for What's Up.

Join us next week as Planetary Radio ventures beyond our own universe and into dimensions beyond the four we experience. Our guest will be Harvard physicist Lisa Randall. Whatever universe you're in, we wish you a great week. Thank you.