Natalie Moore: This is Natalie Moore with Spark Science. Normally I engineer the show but this week I went to the Lunar and Planetary Science Conference (LPSC) to interview planetary scientists about habitability in the solar system. LPSC is hosted near Houston, Texas by the Johnson Space Center and the Lunar and Planetary Institute. Thanks for listening, and enjoy the show.

>> Here we go!

[♪ Blackalicious rapping Chemical Calisthenics ♪]

♪ Neutron, proton, mass defect, lyrical oxidation, yo irrelevant
♪ Mass spectrograph, pure electron volt, atomic energy erupting
♪ As I get all open on betatrons, gamma rays, thermo cracking
♪ Cyclotron, in and any and every mic
♪ You’re on, trans iridium, if you’re always uranium
♪ Molecules, spontaneous combustion, POW

♪ Law of de-fi-nite pro-por-tion, gain-ing weight
♪ I’m every element around

Martin Van Kranendonk: My name is Martin Van Kranendonk. I’m a professor at the University of New South Wales and I study geology. I look at earth’s oldest rocks and I’ve studied really almost all aspects of that about how the crust forms and then what kinds of habitats were there for the oldest life. So I’ve been really fortunate, and really I’m one of the few that have tried to tie those two together.

Natalie Moore: And you said this is your first year at LPSC?

Martin Van Kranendonk: Yeah, so this is my first time coming to Houston. In fact, I’ve never been to Texas before but I’ve always sort of had it in the back of my mind and my research has now gone in a direction where we think we have something to say here. So that happened this morning. It was fun.

Natalie Moore: Do you think you’ll come back next year?

Martin Van Kranendonk: We’ll see. It’s a long way to come always, but last year I was in the states for four different meetings. I had four flights across, so it’s clear there’s so much exciting research that goes on here. It’s always a good draw. I try and shift it around a little bit. The astrobiology conference is always a big one for us.

Natalie Moore: Where is that?

Martin Van Kranendonk: That also changes every two years where it’s held, but it’s always in a different city. Last year it was down in Phoenix in Arizona, two years before it was in Chicago, and before that it was in Georgia, so it moves around.

Natalie Moore: Your talk was really interesting. I know that you just gave that talk, but could you summarize what your session talk was about?

Martin Van Kranendonk: Sure. So we’ve been working on one of the oldest but probably the most convincing evidence of ancient life on earth, this 3.5 billion year old setting in northwest Australia. We’ve made a few discoveries there over the last couple of years that have shifted really the whole way we think about that area. It used to be thought of just as a shallow marine setting, you know, just like a nice day at the beach sort of thing. Now, with some of our studies, it turns out it was a volcanic caldera, very active with actually eruptions and also a lot of faulting, but a huge amount of fluid moving through it.

And we’ve been studying stromatolites, and it turns out they’re living on that circulating fluid in a volcanic caldera.

Natalie Moore: Wow.

Martin Van Kranendonk: And the really important discovery that was made a couple years ago by my PhD student, Tara [sp?], she found a rock only a few centimeters high that turned out to be from a geyser, and it’s unbelievable that something with such fine layering and textures has been preserved for so long but it’s absolutely diagnostic. And so that area so long ago was an exposed land surface.

Natalie Moore: Wow.

Martin Van Kranendonk: And the amazing thing was we found that it was inhabited my microbial life.

Natalie Moore: Cool, and that’s what you study, right?

Martin Van Kranendonk: That’s what our group studies. And so then the implications are we’ve actually got an early earth analog, like an exact replica of what might have occurred on Mars. And the way that research has been going now is it’s starting to question where the origin of life started. And so the model has been that it started in the deep oceans but now there’s more and more evidence to suggest that oceans are not a good place for the life.

Natalie Moore: Yeah.

Martin Van Kranendonk: Even though NASA’s road map is to follow the water in the search for astrobiology, it actually turns out that before you get a living organism, to make the molecules to get to that stage, it’s actually better not to have a permanent wet environment because the simple molecules you get, to make them more complex, to build up to something like RNA or DNA — you know, the genetic material that we pass between each other — you need to have wetting/drying cycles that bonds those molecules together. So really, the oceans now, many people think are out for the origin of life.

Natalie Moore: Yeah, I heard you say that any ocean world probably wouldn’t . . .

Martin Van Kranendonk: I wouldn’t waste my money there! And there was actually a laugh from the audience because there’s huge interest in going to Europa or [inaudible] but actually, if they’re permanently wet — despite the fact they’re covered with ice, that doesn’t matter — but the fact they’re permanently wet means that yeah, they might be habitable if life got started, but it doesn’t look like it has the right ingredients for life to get started.

And that’s the key for astrobiology that I don’t think has really been emphasized enough. It’s been focused on where does life on earth occur. It occurs everywhere where there’s water, of course, in the deep crust, in the atmosphere, in the oceans, lakes, everywhere, but . . .

Natalie Moore: In those volcanic lakes and . . .

Martin Van Kranendonk: In those volcanic lakes and horrible places, you know, extremophiles, but to get life started, you had to have a specific set of conditions. It looks like the most likely environment now is in hot springs on land, and that’s why our research has suddenly gained importance for a community like this. We have a deep time analog of that setting, and the question is: Can it provide all the things you need to get life started, like complexity, mixing this and that, does it have the right chemical elements to get things started, can it make polymers, can it build that complexity?

And the answer turns out to be: Yes! In our 3.5 billion year old analog, which is getting pretty close to the time when life probably started on earth, we have the elements. We’ve got the complexity. We can see life getting a foothold in hot springs and so then that has enormous implications for where else to go in the solar system to look for life, you know?

Natalie Moore: So how do we know there wasn’t hot springs on Europa and Enceladus, these places that you think might not have been able to sustain life?

Martin Van Kranendonk: That’s a good question, and the truth is, we don’t. We don’t know that there wasn’t at some point exposed land, and then it got covered by water. But from what we do know in studies on the earth and other nearby planetary systems, we know the atmospheres formed very early, and in fact the oceans are modeled to have rained out onto the earth in the first ten million years or so.

So it’s probably the same for those icy water worlds of the moons of Jupiter and Saturn. They would’ve formed very early, and so it’s unlikely there were conditions where there was surface water and land and hot springs in the right amounts. It’s probable that it was an ocean world from the very start. We don’t actually know, but it’s not very likely.

Natalie Moore: So where are you looking besides earth, then?

Martin Van Kranendonk: Well, it’s funny because I only really got initiated into like the search for life on Mars a few years ago and I wasn’t very impressed, I have to say. I wasn’t very excited, because it didn’t have evidence of an ocean, you know, it had only a short period where it was wet.

Natalie Moore: And they don’t even know how long.

Martin Van Kranendonk: They don’t even know how long, so I thought, “Eh, that doesn’t sound like a very interesting place to go.”

Natalie Moore: Yeah.

Martin Van Kranendonk: But now that we know that there was a period where there was water on the surface and that it must have lasted for at least hundreds of thousands if not millions of years, possibly tens or even a hundred million years, and we know it had volcanoes all through that time and that’s the right mixture to get hot springs. And then there have been discoveries already from 2007 and 2008 of hot spring deposits on Mars. That’s very well-known now — beautiful opaline silica actually on the flanks of a volcano just where you’d find hot springs today.

And it’s like, oh my god! They’ve got hot spring deposits, and on Earth, hot spring deposits host life, not just now, but all through the geological record right back to 3.5 billion years ago. So my question to you is: If you had anywhere on the Red Planet to go, and people have talked about going to caves, looking at the icy polar caps and the cryosphere in the surface, or on hot spring deposits, where would you go? What’s the most likely chance of success? It’s hot springs every time, not only because they harbor life, but they have this unique capacity to preserve an entomb life.

Because the hot water is flowing out, the microbes are living in that hot water but the hot water is filled with silica, and the silica actually entombs the microbial communities right away. And so it’s like instantaneous mummification.

Natalie Moore: Wow.

Martin Van Kranendonk: And that preserves those signs of life back through the eons of time, whereas in many other systems, they get degraded, and because minerals regrow and form, they get coarse and stuff. But the beautiful thing about those, the exciting thing about those Martian deposits is they are still made up of opal, and opal is like a semi-stable mineral. It will re-crystalize and form bigger grains if you touch it with any heat, or you know, cover it with another layer of rock or something. But this hasn’t changed from opal. So the preservation potential is unbelievably good. It’s just, it’s so exciting!

Natalie Moore: Even with all the radiation and . . .

Martin Van Kranendonk: Yeah the radiation . . .

Natalie Moore: . . . in the atmosphere?

Martin Van Kranendonk: Yeah the radiation is a problem, but that’s a problem for any surface rock, so anything that they want to go and look for organics is a problem. What I haven’t read about, and that’s my own limitation, I haven’t read about “does silica protect organics?” But the thing is, and so there’s two things in this debate. One is sort of like, okay, where would you go to find signs of life? And what are those signs of life going to be? So, organics is always talked about as like the gold standard, right? If you find a biomolecule that’s uniquely made by life, you’ve hit a home run, right?

So, but the reality is, three billion years, it’s very unlikely that a real biologically made, organic molecule is going to survive. We don’t know it from Earth. For course, Earth has different conditions. It’s got heat and metamorphism, but we do have areas that are very well preserved, and we just don’t get that preservation, and with the radiation on the surface of Mars, those molecules may well break down quite rapidly.

And you know, the guide that we use to go and look for signs of life in these very old rocks is actually shapes and structures, you know. Even the microfossils themselves, they leave behind textures that you can see in the rock. Textures is almost always the first guide that we have to look for signs of life.

Natalie Moore: And now we have so many imaging instruments.

Martin Van Kranendonk: Exactly. Let’s go look for those features that we know from on Earth and stuff. So, of course, you know, you want to, and because also there have been claims of life on Mars before, the field is controversial, so you want to be really sure. But on the other hand, you may strike out on your gold standard, and what are you left with? And there are lots of things that you can do, and that’s really what we’re advocating for, is a holistic, environment and contextually based search proposal.

Because there are some sites that have been suggested. “Oh, we’re going to go here and drill into an interesting rock.” But they don’t really know what they’re looking for, and would you risk two billion dollars on something you don’t really know what you’re looking for? I don’t know, it’s been interesting to see how that is developing. And you know, there are a lot of very intelligent minds and big groups of people working on this problem, so it’s not an easy solution, but we feel that the most likely chance of success to look for ancient life of Mars would be in a hot spring.

Natalie Moore: So you think that NASA might choose — the next landing site that hasn’t been chosen yet — are you at all hopeful that there might be hot springs there?

Martin Van Kranendonk: Listen, we’re in the top three sites that are still to be decided on. We’ve been at the landing site workshops for the last two years. I presented at the last one last February. So listen, we’re still in the game. It’s not clear how that decision will be made, but we’re still having input and that’s why we’re still participating in these meetings. And what’s been interesting is to see that there are more and more people talking about hot springs from different points of view. So I heard one today about a really acidic volcanic lake. We heard about the studies that Steve Ruff is doing in Chile where there are these direct analogs for the features that he’s found. It’s just amazing.

So that’s good to see. There is movement, but whether that will turn out to be the right site for Mars 2020 we don’t know. And of course, that’s a mission with many different objectives and many different tools, so, you know, we’ve sort of suggested one thing to look at, but they’re interested in a whole program. And so there are always competing interests in a complex mission.

[♪ Janelle Monae singing Wondaland ♪]
♪ Early late at night
♪ I wander off into a land
♪ You can go, but you mustn’t tell a soul
♪ There’s a world inside
♪ Where dreamers meet each other

Natalie Moore: So if you, your goal of, you know, finding or going to Martian hot springs, what landing site are you advocating for?

Martin Van Kranendonk: Well, whether or not Mars 2020 goes, we would love to send a mission and just grab one of those micro-digitate opaline silica nodules from home plate. That just looks so compelling and I think it would be one of those cases where, if there’s no signs of life, then I would feel like there’s not probably a very high possibility of life on Mars at all. And if we were able to get those back in the lab and have a look, it would be incredibly exciting.

Natalie Moore: So, this might be a stupid question, but is Australia going to Mars?

Martin Van Kranendonk: Australia is not going to Mars. We’ve only just announced just a few months ago that we’re going to have a space agency.

Natalie Moore: Yes!

Martin Van Kranendonk: We’ve never had a space agency, but finally we got one.

Natalie Moore: [Laughing.]

Martin Van Kranendonk: And um, so . . .

Natalie Moore: The more the better.

Martin Van Kranendonk: Sorry?

Natalie Moore: The more the better.

Martin Van Kranendonk: The more the better. New Zealand’s got one, and so we’ve joined forces with New Zealand from the astrobiology side and it could be a really nice project to say, “Let’s go to Mars and grab those things.” So we’ve been thinking about that for the future, for sure.

Natalie Moore: Yeah. A little off topic, but I hope that one day, if the Mars 2020 rover can actually pick up samples and store it, if they can’t go back and get those samples, I hope that sooner than NASA somebody else can go there and pick them up.

Martin Van Kranendonk: Exactly.

Natalie Moore: But I don’t know if politics would allow for that. But that . . .

Martin Van Kranendonk: Right.

Natalie Moore: But that would be in science’s best interest.

Martin Van Kranendonk: That would be in science’s best interest, that’s very true. And there’s a lot of activity now. Like in 2020, I think there are five missions launching to Mars.

Natalie Moore: Yeah.

Martin Van Kranendonk: It’s not just NASA. Europe’s going, India I think is sending up a probe . . .

Natalie Moore: China.

Martin Van Kranendonk: The United Arab Emirates, China, so, it’s getting busy. And now, of course Elon Musk wants to go and live there, so . . .

Natalie Moore: I don’t know why. I’ve been, I’m also part of the Mars group at Western, and all of us are here, and after looking at thousands of pictures of Mars from a mass cam instrument, I would [laughing] never want to go there.

Martin Van Kranendonk: [Laughing] You wouldn’t want to go.

Natalie Moore: It’s really interesting [laughing], but I’d never want to go there. It’s . . . this place is paradise.

Martin Van Kranendonk: Oh totally, exactly.

Natalie Moore: I don’t even know if I would want to go to any other place after looking at pictures of . . . I mean, they’re all beautiful with all the moons and all the planets, but Earth is paradise.

Martin Van Kranendonk: It’s not home. Absolutely. And you know, for the amount of money, you know, one thing that they don’t talk about for those sort of colonizations is the amount of money involved, right? It’s just astronomical, literally. And so why wouldn’t you spend that money on fixing up paradise? Anyway, so those are longer term issues.

Natalie Moore: Yeah. So, if we do find any type of biosignature, what would that look like? Like, what is, I guess what I’m asking is what is a biosignature? What are you looking for specifically?

Martin Van Kranendonk: Yeah, that’s a great question also, and a very complicated field of study, and highly controversial. So the biomolecules, like I said, are sort of the gold standard, but there’s always the worry about contamination because . . .

Student: It could be us.

Martin Van Kranendonk: It could be us, we could be introducing life. There are ways to identify whether that’s the case or not. But there are a lot of textural biosignatures, so, like, preserved microfossils, preserved structures in the rock that are only made by microbial communities that are not just geology.

Natalie Moore: What would that look like?

Martin Van Kranendonk: Well, you know, on Earth, really for three billion years of Earth history, it was dominated by structures called stromatolites. These are layered rock structures but they’re actually built by microorganisms. So they don’t look anything like normal geology, like ripples on the sand of the beach and that sort of thing, stuff we’re all familiar with. It looks completely different. And if you’re really attuned to it, if you’ve worked in those for a long time, you see how the biological part of the rock interacts with the geological part as two separate processes that build the units that we then go and see. So stromatolites are a big feature, microbial surfaces, microfossils. And then the microfossils often leave behind distinct textures that are a very fine scale. Those can also sometimes also be completely unique and diagnostic.

So those are the kinds of things that we have to look at. And for that, in a lot of cases, the samples would have to come back to Earth. So that’s the importance of the Mars 2020 mission is to really bring those samples back. We can do a lot on Mars now, but still, a lot of that really detailed investigation has to come back.

Natalie Moore: Because even the chem cam or the, you know . . .

Martin Van Kranendonk: Yeah.

Natalie Moore: The APXS there, we could, it’s still not fine enough.

Martin Van Kranendonk: Some of it’s not fine enough, exactly, and you know, there were different proposals for instruments that could have gone on Mars 2020 and one of them was a really high resolution, advanced optical microscope, for example. And then you couldn’t really look for those textures in situ and see “is that sample of interest to collect? Is that sample of interest or not?” But there are other [inaudible] they’ve put on which do equally fascinating things.

So it’s a tradeoff, and, you know, I mean, what’s unbelievable about this mission is the amount of material and scientific instruments they can take out. The amount of science they can do there is just fantastic, even compared with two Rovers ago, you know, it’s increased in size almost by an order of magnitude, and you know, it’s just going forward in leaps and bounds. So I’m really excited for the future of students in science because they’ve got a great potential for making amazing discoveries still.

Natalie Moore: Yeah, I’m excited that I’m in my twenties during all of this.

Martin Van Kranendonk: Yeah! Absolutely. You’ll be right on the front foot of those new discoveries, so . . .

Natalie Moore: Yeah [laughing.] The regular host of this show is obsessed with volcanic vents.

Martin Van Kranendonk: Oh yeah.

Natalie Moore: You’re very into hot springs, but what about volcanic vents? Do you think there’s any, that there would be any hope there?

Martin Van Kranendonk: By volcanic vents, do you mean where volcanoes erupt at the surface or do you mean the black smokers, these hydrothermal vents at the deep oceans?

Natalie Moore: That’s what she means, yeah.

Martin Van Kranendonk: The black smokers, yeah, okay. So, I mean, the interesting thing is that these black smoker, these hydrothermal vents and hot springs, they share a lot in common. It’s hot water interacting with rock, altering and having those sharp chemical gradients and temperature gradients, that makes it exciting in terms of complexity in reactions. And sure, I mean, that’s been the preferred model for the last 30 years for the origin of life, and still is for many very big groups.

But as I mentioned and as I said in my talk, and this is the work of others, a permanently wet environment like the deep oceans is a problem for getting life started. It’s too dilute, the black smokers particularly are too acidic and too hot, but they just don’t have the capacity to make these long-chain organics. And we are based on long-chain organics, and all of life is, like, not just us complex things but every single microbe has got these organic polymers. That’s what makes their cell wall, it makes the DNA, it makes everything. And so to get that, you have to have that power of wetting and drying to bind those molecules together.

Natalie Moore: Or else they would just break apart?

Martin Van Kranendonk: They just dissolve. It’s just like sugar in water, it’s just soluble. They just dissolve, and that’s been known for a long time. And so the magic of life is making a protective layer that keeps that dissolvable material inside, together, collective, organized, self-replicating. Those are all the things that we don’t understand. There’s still just an enormous amount of intensive research to do.

But one thing I’m very excited about is a developing field called messy chemistry. Like, you would’ve been taught in high school about the Linnean categorization of birds and species, it’s all in this tree of life and everything, it all goes from A to B to C very nice and organized. But now there are these fields that, for something as complex as life, or a city, or a neural network to develop, it’s not linear. You just throw stuff together and see what happens. You need, like, multitudes of reactions, and one reaction will change what happens with the other reactions, and, you know, it’s non-linear.

So this idea of non-linear dynamics is increasingly interesting in terms of building complexity. The challenge is to see how you can focus that messiness into something that then becomes organized. And, I think, as a community, we’re only just starting on that, so for me, that’s a huge field of opening up in origin of life studies.

Natalie Moore: Yeah, that was actually my next question, was, what are you most excited about for the future of your field? [Laughing.]

Martin Van Kranendonk: Well, I think, I think that would be it. It would be starting to devise experiments where you can somehow sort of manufacture this idea of messy chemistry. Not just have one reactive incubator, but have 25, and see what happens when you mix them all together or change sequences, you know. Now, with computer technology controlling flow rates and inputs and, you know, we’ve gotten so sophisticated, you can do a whole bunch of things and just let it run for 15 years and see what comes out the other − who knows. I’m sure there are people smarter than me who can devise those kinds of things. But, yeah, that’s where I think the next big discoveries are going to be made.

And it’s mixing, you know, biologists with chemists with physicists and biologists and put them all together, and put their minds at looking at this, at this problem. I think that’s a really exciting field.

Natalie Moore: So is it, would it be like chaotic chemistry? [Laughing.]

Martin Van Kranendonk: Yeah, it is almost trying to harness chaos, you know. And you can think of the Big Bang like that, you can think of a star like that, as harnessing that energy, and then finding out how you organize that into a system that becomes regulated somehow. Because life is a chemical system, but it’s got an organizational framework to it that actually runs against entropy, right? Entropy breaks everything down, second law of thermodynamics is always going to make a steady state at an even level, but we build up against that and life builds up against that. So, at some point, we have to start understanding how that works in a natural system and what the dividing line is between chemistry and life.

So those are still very big questions.

Natalie Moore: It’s interesting [laughing.]

Martin Van Kranendonk: Yeah, it’s amazing once you start thinking about it.

Natalie Moore: Yeah, I was really kind of surprised about the Titan, Enceladus, Europa [inaudible] because I was like . . .

Martin Van Kranendonk: Yeah, I think a lot of people were.

Natalie Moore: Yeah, but that’s important though, for also the listeners to kind of get at, because we, at least our show, is really hopeful. We’re really optimistic.

Martin Van Kranendonk: The thing I guess that we’re learning, too, and you know if we take single end members you might say, “This planet good, that planet bad.” But there’s exchange of information between planets, too. We know we’ve got Mars meteorites on Earth and there are probably Earth meteorites on the moon, and so, you know, there is exchange. And so, that question of, “Did life arise only once in one place, or could it have gone somewhere else if the conditions were right?” We just don’t know.

But it’s maybe naive to say, “Oh, it couldn’t happen there, it could happen there.” Habitability is still very important. Does it have the right conditions? But also, as I’ve been stressing, does it have the conditions to make life? So people have often suggested that all life started on Mars and then came to Earth, but I don’t feel that solves the problem. And Earth, we know, has the right conditions, or at least as far as we know, so it’s a bit like you not wanting to go to Mars to live there. We’ve got everything we need here. It’s just how we manage it, so, a little bit like that with getting started for life, too. My feeling is it’s a home-grown affair.

Natalie Moore: Yeah, and there was one guy in the end of that session, that whole session, he went up, and he said something about how it’s, it’s really easy to, to make those polymers if you have the right conditions, so why would you, why would it just be in one spot, like one . . .

Martin Van Kranendonk: Yeah.

Natalie Moore: . . . one planet, that it could start when it could . . .

Martin Van Kranendonk: Yeah.

Natalie Moore: . . . be in a bunch of places.

Martin Van Kranendonk: Yeah. Exactly. So, and you know, the basic building blocks of life as we know it are common throughout the universe. Carbon is very common, oxygen is everywhere, and stuff, so that, that basic building blocks is simple. It’s the organizational framework that’s more complex.

Natalie Moore: Before I let you go, is there anything else that you wanted to say that I didn’t get to ask you?

Martin Van Kranendonk: No, I don’t think so. I think we touched, really, on most things. I mean, it’s nice that you asked about the future and the exciting developments and I think we’ve spoken about that, so . . .

Natalie Moore: Cool!

Martin Van Kranendonk: I’m happy.

Natalie Moore: Well thank you for taking the time to talk with me.

Martin Van Kranendonk: My pleasure.

Natalie Moore: We really appreciate it.

Martin Van Kranendonk: Oh, great!

[♪ Janelle Monae singing Wondaland ♪]

♪ Dance in the trees ♪
♪ Paint mysteries ♪
♪ The magnificent droid plays there ♪
♪ Your magic mind ♪
♪ Makes love to mine
♪ I think I’m in love, angel
♪ Take me back to Wondaland
♪ I gotta get back to Wondaland
♪ Take her back to Wondaland
♪ She thinks she left her underpants

Thanks for listening to Spark Science. If you missed any of the show, go to our website, Sparksciencenow.com. If there’s a science idea you’re curious about, send us a message on Twitter or Facebook at SparkScienceNow. Spark Science is produced in collaboration with KMRE Spark Radio and Western Washington University. Today’s episode was recorded on-location at The Woodlands Convention Center in The Woodlands, Texas.

Our producer is Regina Barber Degraaff, our audio engineers are Natalie Moore, Andra Nordin, and Tori Highley. Our theme music is “Chemical Calisthenics” by Blackalicious and “Wondaland” by Janelle Monae.

[♪ Blackalicious rapping Chemical Calisthenics ♪]

♪ Lead, gold, tin, iron, platinum, zinc, when I rap you think ♪
♪ Iodine nitrate activate ♪
♪ Red geranium, the only difference is I transmit sound ♪
♪ Balance was unbalanced then you add a little talent and ♪
♪ Careful, careful with those ingredients ♪
♪ They could explode and blow up if you drop them ♪
♪ And then they hit the ground ♪

[End of podcast.]