Spark Science welcomes the return of Astrophysicst Dr. Kevin Covey. In this episode we discuss how extra-solar planets or “Exoplanets” are found using three methods and how they are found using a space observatory named Kepler. Exoplanets are other worlds found outside of our solar system and they are also something the general public can now name. Listen to this show to find out how……
(Natalie) This is Natalie Moore with Spark Science. Normally I engineer the show but this week I went to the Lunar and Planetary Science Conference to interview planetary scientists about habitability in the Solar System. LPSC is hosted near Huston Texas by the Johnson Space Center and the Lunar and Planetary Institute. Thanks for listening and enjoy the show.
[♪ 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 betatron, gamma rays thermo cracking
♪ Cyclotron 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) My name’s Martin Van Kranendonk, I’m a professor at the University of New Southwest and I study geology. I look at Earth’s oldest rocks. I’ve studied almost all aspects of that. How the crust forms, and then what kind of habitats were there for the oldest life. I’ve been really fortunate and really I’m one of the few that have tried to tie those two together.
(Natalie) You said this is your first year at LPSC?
(Martin) Yeah. So this is my first time coming to Huston, in fact I’ve never been to Texas before but I’ve always sort of had it in the back of my mind and now my research is going in a direction where we think we’ve got something to say here. That happened this morning.
(Natalie) Do you think you’ll come back next year?
(Martin) 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 um, its clear there’s so much exciting research going on here. It’s always a good draw. So, I try to shift it around a little bit. The astrobiology conference is always a big one for us.
(Natalie) Where’s that?
(Martin) That also changes every two years it’s held. 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, down in Georgia. So, it moves around.
(Natalie) You’re talk was really interesting. I know that you already, you just gave that talk but could you quickly summarize what your session talk was about?
(Martin) Sure. 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 that have shifted really the whole way we think of that area. It used to be thought of as just a shallow marine setting. Just like a nice day at the beach kind of thing. But now, our discoveries and the mapping, it turns out it was a volcanic caldera, very active with eruptions and then also a lot of faulty but a huge amount of fluid running through it. We’ve been studying stromatolites. It turns out they’ve been living on that circulating fluid in a volcanic caldera.
The really important discovery that was made a few years ago by my PhD student Tara, she found a rock only a few centimeters high that turned out to be from a geyser. It’s unbelievable that something with such fine layering and texture has been preserved for so long but it’s absolutely diagnostic. That area, so long ago, wasn’t exposed land surface. The amazing thing was, we found it was inhabited by microbial life.
(Natalie) Cool. That’s what you study, right?
(Martin) That’s what our group studies. The implications are, we actually got an early earth analogue, an exact replica, of what might have occurred on Mars. The way that research has been going now, it’s starting to question where the origin of life started. The model has been that it started in the deep oceans but now there is more and more evidence to suggest that oceans are not a good place for the life 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) I heard you say that any ocean world probably wouldn’t . . .
(Martin) I wouldn’t waste my money there. [Laughing.] There’s was actually a laugh from the audience because there’s a huge interest in going to Europa or Enceladus, but actually, if they’re permanently wet, despite the fact that they are permanently covered in ice, that doesn’t matter, but the fact that they’re permanently wet means that, yeah, they may be inhabitable if life got started, but it doesn’t look like it has the right ingredients for life to get started. That’s a 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 there is water of course, in the deep crust, in the atmosphere, the oceans, lakes, everywhere, and volcanic lakes and horrible places, extremophiles, but to get life started, you had to have a specific set of conditions. It looks like the most likely environment now is on hot springs on land. That’s why our research has suddenly gained importance for a community like this because we have a deep time analog of that setting.
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 a complexity, and the answer it turns out to be yes. In our 3.5 billion year old analogue that’s getting pretty close to the time when life started on Earth, we have the elements, we have the complexity, we can see life getting a foothold in hot springs. Then, that has enormous implications for where else to go in the Solar System to look for life.
(Natalie) How do we know there wasn’t hot springs on Europa and Enceladus and these places that you think might not have been able to sustain life?
(Martin) 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 what we do know in studies in the Earth and other nearby planetary systems, we know the atmospheres form very early and in fact, the oceans are modeled to have rained out onto the earth in the first 10 million years or so.
So, it’s probably the same for those icy water worlds of the moons of Jupiter and Saturn. They would have formed very early and it’s unlikely that 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 beginning. We don’t actually know but it’s probably unlikely.
(Natalie) So, where are you looking besides Earth?
(Martin) It’s funny because I only really got initiated into the search for life on Mars a few years ago. I wasn’t very impressed I have to say. I wasn’t very excited because it didn’t have evidence of an ocean. It had only a short period where it was wet.
(Natalie) They don’t even know how long.
(Martin) They don’t even know how long so, that doesn’t sound like a very interesting place to go. But, now that we know there was a period where there was water on the surface and it must have lasted for at least hundreds of thousands if not millions of years, possibly 10s or even 100 million years, we know it had volcanoes throughout that whole time and that’s the right mixture to get hot springs. Then, there have been discoveries from 2007/2008 of hot spring deposits on Mars. That’s very well-known now. Very beautiful opaline silica actually on the flanks of a volcano just where you’d find hot springs today. 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 cryosphere surface or on hot spring deposits, where would you go? What’s the most likely chance of success? Hot springs every time. Not only because they harbor life but because they have this unique capacity to preserve and entomb life. The hot water is flowing out, the microbes are living in that hot water, but the hot water is filled with silica.
The silica actually entombs the microbial communities right away. It’s like intentions mummification and that preserves those signs of life back through the eons of time where through many other systems they got degraded. Because minerals regrow and form like a core and stuff, but the beautiful thing about those, the exciting thing about those Martian deposits is their still made up of opal.
An opal is like a semi-stable mineral. It will recrystallize and make bigger grains if you touch it with any heat or cover it with a 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) Even with all the radiation and the atmosphere?
(Martin) Yes. The radiation is a problem but that’s a problem for any surface rock. Anything that they want to go and look for organics is a problem. What I have not read about, that’s my own limitation, I haven’t read about, does silica protect organics? But the thing is, until there is two things in this debate; one is sort of like, where would you go to find signs of life and what are those signs of life going to be? So organics has always talked about us like the gold standard.
If you find a biomolecule that’s uniquely made by life you’ve hit a home run. But the reality is, 3 billion years, it’s very unlikely that a real, biologically made molecule, is going to survive. We don’t know it from Earth. Of 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.
With the radiation on the surface of Mars, those molecules may break down very rapidly. You know, the guide we use to go and look for signs of life in these very old rocks is actually shapes and structures. Even the microfossils themselves leave behind textures you can see in the rock. Textures is almost always the first guide that we have to look for signs of life.
(Natalie) That’s why we have so many imaging instruments.
(Martin) Exactly. Let’s go look for those features that we know from on Earth and stuff. 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 might strike out on your gold standard and what are you left with? There are lots of things you can do. That’s really what we’re advocating for, is a holistic environment and contextually based search proposal. There’s some sights that have been suggested, we’re going to go here and drill into an interesting rock but they don’t really know what they’re looking for. Do you risk 2 billion dollars on something you don’t really know what you’re looking for? I don’t know. It’s interesting to see how that’s developing. There are a lot of very intelligent minds and big groups of people working on this problem so it’s not an easy solution. We feel that the most likely chances of success to look for ancient life on Mars would be in a hot spring.
(Natalie) Do 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) 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, we’re still in the game. It’s not clear how that decision will be made but we still have input and that’s why we are still participating in these meetings.
What’s been interesting is to see that there are more and more people talking about hot springs from different points of view. I heard one today about a really acid volcanic lake. We heard about the studies that Steve Ruff is doing in Chile where there are all of these direct analogs for the features that he’s found. It’s just amazing. 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.
Of course that’s a mission with many different objectives and many different tools. We have suggested one thing to look at but they are interested in a whole program. 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) With your goal of finding or going to Martian hot springs, what landing site are you advocating for?
(Martin) Whether or not Mars 2020 goes, we would love to send a mission and just grab one of those micro digitype opaline silica nodules from home plate. That just looks so compelling. I think it would be one of those cases where if there’s no sign of life, then I would feel like there’s not probably a very high possibility of life on Mars at all. If we were able to get those back in the lab and take a look, it would be incredibly exciting.
(Natalie) This might be a stupid question but, is Australia going to Mars?
(Martin) 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. We’ve never had a space agency but finally we’ve got one.
(Natalie) The more the better.
(Martin) The more the better. New Zealand has got one so, we’ve joined forces with Now Zealand from the astrobiology side and it could be a really nice project to say, “Let’s go to Mars and grab those things.” We’ve been thinking about that for the future for sure.
(Natalie) A little off topic but I hope 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 can go there and pick them up. But I don’t know if politics would allow for that. That would be like, in science’s best interest.
(Martin) It would be in science’s best interest. That’s very true. There’s a lot of activity now. In 2020 I think there are 5 missions launching to Mars. It’s not just NASA. Europe is going, India I think is sending up a probe, the United Arab Emirates, China, so it’s getting busy. Of course now Elon Musk wants to go and look up there.
(Natalie) I don’t know why. I’m also part of the Mars group at Western and all of us are here. After looking at thousands of pictures of Mars from the mass com instrument. I would never want to go. It’s really interesting but I would never want to actually go there. [Laughing.] This place is paradise. I don’t know if I would even want to go to any other place after looking at pictures of, I mean, they’re all beautiful, all the moons and all the planets but, Earth is paradise.
(Martin) It’s not home. Absolutely. For the amount of money, one thing they don’t talk about for those sort of colorizations, is the amount of money involved. It’s just astronomical, literally. Why wouldn’t you spend that money on fixing up paradise? Anyway. Those are longer term issues.
(Natalie) If we do find any type of bio signature, what would that look like? What is I guess what I’m asking, what is a bio signature? What are you looking for specifically?
(Martin) 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 of contamination.
(Natalie) It could be us.
(Martin) It could be us, we could be introducing life. There are ways to identify if that’s the case or not. There are a lot of textural bio signatures like preserved microfossils, preserved structures in the rock that are only made by microbial communities that are not just geology.
(Natalie) What would that look like?
(Martin) Well, on Earth, for 3 billion years of earth history, it was dominated by structures called stromatolites. These are layered rock structures but they are actually built by microbes. They don’t look like any normal geology, ripples on the sand on the beach and that sort of thing, stuff we’re all familiar with. It looks completely different.
If you are really in tuned to it and have worked with 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 at a very fine scale. Those can also sometimes be completely unique in diagnostic. Those are the kinds of things that we have to look at.
For that, in a lot of cases, the samples would have to come back to Earth. 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) Even the com scan [sp?] or the AP excess [sp?] there, it’s still not fine enough.
(Martin) Some of it is not fine enough, exactly. There were different proposals for instruments that could have gone on Mars 2020, one of them was a really high resolution advanced optical microscope for example. Then you could really look for those textures and [inaudible], is that sample of interest to collect? Is that sample of interest or not? But there are [inaudible] stones they put on that do equally fascinating things. It’s a tradeoff.
What’s unbelievable about this mission is the amount of material and scientific instruments that they can take up. The amount of science they can do there is just fantastic. Even compared with two rovers together, it’s increased in size almost by an order of magnitude and it’s just going forward in leaps and bounds. I’m really excited for the future of students in science because they have a great potential for making amazing discoveries still.
(Natalie) I’m excited that I’m in my 20s for all of this.
(Martin) Absolutely. You’re right on the front foot of those discoveries.
(Natalie) The regular host of this show is obsessed with volcanic vents.
(Martin) Oh yeah.
(Natalie) You were very into hot springs but what about volcanic vents? Do you think that there would be any hope there?
(Martin) By volcanic vents do you mean where volcanoes erupt at the surface or do you mean the black smokers, these hydrothermal vents that are in the deep oceans.
(Natalie) That’s what she means.
(Martin) The black smokers. Yeah, OK. I mean, the interesting thing is that, these black smokers, 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 make it exciting in terms of complexity and reacts. Sure, 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 deep oceans is a problem for getting life started. It’s too dilute. The black smokers specifically 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.
All of life is, 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. To get that, you have to have that power of wetting and drying to bind those molecules together.
(Natalie) Or else they would just break apart?
(Martin) They just dissolve. It’s like sugar in water. It’s just soluble, it just dissolves and that has been known for a long time. The magic of life is making a protective layer that keeps that dissolvable material inside together, collative, organized, self-replicating, those are all the things that we don’t understand.
There’s still an enormous amount of intensive research to do. One thing I’m very excited about, a developing field called Messy Chemistry. Like, you would have been taught in high school about the Linnaeus categorization of birds and species, it’s all in this tree of life and it all goes from A to B to C very nice and organized. 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 multitudes of reactions. One reaction will change what happens with the other reaction. It’s nonlinear.
This idea of nonlinear dynamics is increasingly interesting in terms of building complexity. The challenge is to see if you can focus that messiness into something that is then organized. I think as a community we’re just starting on that. For me that’s a huge field opening up in an origin of life studies.
(Natalie) That was my next question, what are you most excited about for the future of your field?
(Martin) I think that would be it. I think it would be starting to devise experiments where you can somehow manufacture the idea of messy chemistry. Not just have one 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, it’s, you know, so sophisticated. It can do a whole bunch of things and just let it run for 15 years and let it come out the other. Who knows?
I’m sure there are people who are smarter than me who can devise those kinds of things. That’s where I think the next big discoveries are going to be made. It’s mixing biologists with chemists and physicists and biologists and put them all together and put their minds towards looking at this problem. I think that’s a really exciting field.
(Natalie) Would it be like chaotic chemistry?
(Martin) Yeah, it is almost trying to harness chaos. You can think of the big bang like that, you can think of a star like that, it’s harnessing energy. Then finding out how you organize that into a system that becomes regulated somehow. Life is a chemical system but it has an organizational framework to it that actually runs against entropy. Entropy actually breaks everything down.
The second law of thermodynamics is always going to make a study state at an even level. We build up against that, life builds up against that. 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. Those are still very big questions.
(Natalie) It’s interesting.
(Martin) It’s amazing once you start thinking about it.
(Natalie) I was really surprised about Titus and Enceladus, Europa diagnosis.
(Martin) I think a lot of people were.
(Natalie) That’s important though for also the listeners to kind of get at. At least our show is very hopeful. We are optimistic.
(Martin) The thing I guess that we are learning too, if we take single end members you might say, this planet good, that planet bad, but there is an exchange of information between planets too. We know we have Mars meteorites on Earth and there are probably earth meteorites on the moon and there is exchange. 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 its maybe naive to say, it couldn’t happen here, it couldn’t happen there. Habitably is still very important. Does it have the right conditions? Also, as I’ve been stressing, does it have the conditions to make life? People have often suggested that life started on Mars and then came to Earth. I don’t feel that solves the problem.
Earth, we know, has the right conditions or at least as far as we know so it’s a bit like you don’t want to go to Mars to live there. We’ve got everything we need here, its just how we manage it. It’s a little bit like that in getting started with life too, my feeling is it’s a homegrown affair.
(Natalie) There’s one guy in the end of that whole session that went up and said something about how its really easy to make those polymers if you have the right conditions so why would it be only it one spot, one planet, that it could start when it could be in a bunch of places.
(Martin) Exactly. The basic building blocks of life as we know it are common in the universe. Carbon is very common, oxygen is everywhere. The basic building blocks are simple. It’s the organizational framework that’s more complex.
(Natalie) Before I let you go, is there anything else you wanted to say that I didn’t get to ask you?
(Martin) I don’t think so. I think we touched on most things. It’s nice you asked about the future and the exciting developments. I think we’ve spoken about that. I’m happy.
(Natalie) Cool. Well, thank you for taking the time to talk with me. We really appreciate it.
[♪ 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 me back to Wondaland
♪ Me thinks she left her underpants
♪ Take me back to Wondaland
♪ I gotta get back to Wondaland
(Natalie) 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 Tory Highly. Our theme music is Chemical Calisthenics by Blackalicious and Wondaland by Janelle Monea.
[♪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 in
♪ Careful, careful with those ingredients
♪ They could explode and blow up if you drop them
♪ And they hit the ground