Planetary Radio: Space Exploration, Astronomy and Science - Where Do We Come From? The Origin of Life

Episode Date: January 30, 2019

Astrobiology is the discipline that explores the origin of life in the universe, and whether life exists anywhere other than Earth. It’s an increasingly exciting field according to University of Washington Research Associate Michael Wong. Mike reviews the current thinking and provides some of the chemical basis for life as we know it, and possibly as we don’t know it. Planetary Society Senior Editor Emily Lakdawalla explains why we don’t see stars in many images of bodies across the solar system, while Society CEO Bill Nye marks the end of the US government shutdown that has hampered so much science. Five more winners will receive copies of First Man in this week’s What’s Up space trivia contest. Learn more at:  http://www.planetary.org/multimedia/planetary-radio/show/2019/0130-2019-michael-wong-life-origin.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Where do we come from? This week on Planetary Radio. Welcome. I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. How and where did life begin? That's the subject of my conversation with scientist Michael Wong. It's a great review of the current thinking about our origins and even some of the chemical basis for life as we know it and as we don't know it. Bill Nye stops by to celebrate the end of the U.S. government's partial shutdown,

and we've got five more Blu-ray copies of First Man to give away when Bruce tells us what's up. Senior editor Emily Lakdawalla has done some more of her great work for the Planetary Society website. Emily, you have written about one of these things that now and then troubles me enormously. When you hear from, I won't even call them skeptics because skeptics ought to base their arguments on fact. But this is one of the reasons that there is a small minority of misled people who believe that we don't go to space and that humans didn't walk on the moon. It's your January 28 blog post called Why Are There No Stars in Most Space Images? And I want to say you did a terrific job, better than I've seen anywhere else, of explaining why this is. So why don't we? Well, there are three main factors that affect

whether you can see stars in images that are taken in space. You think that staring up at black space at night on Earth, you can see lots of stars. And so if you start thinking about it, it seems a little strange that if you see a photo of like an asteroid in space against the blackness of space, you don't see stars in those images. But the fact of the matter is that that asteroid is typically lit by the sun. And so any sunlit surface is so bright, that the exposure setting that you use on your camera is so short that it's not long enough to actually capture any of the faint stars that are sitting there in the background. So exposure setting is one of the things that affects whether or not you can see stars. It also has to do with the sensitivity of your camera. There are lots of

cameras that go to all different destinations in space. And the more sensitive a camera is, the more capable it is of seeing stars. There's some cameras that get sent to places like Mercury, where there's a lot of sunlight. And so those cameras are a lot less sensitive than, say, the ones that are sent to Pluto, like the ones on New Horizons. Those can actually gather much more starlight in their cameras than the spacecraft cameras that are sent to destinations close to the sun. and the spacecraft cameras that are sent to destinations close to the sun. And finally, there's a factor called dynamic range. And that has to do with your ability to actually detect both bright things and dim things in the same image.

Human eyes actually have pretty wide dynamic range. We're capable of seeing details in outdoor settings where there's things going on both in sunlight and in shadow. But most consumer cameras are actually very poor at catching things in wide dynamic range. Space cameras can do a pretty good job of getting both dim things and bright things, but you actually have to process the images to be able to see the details that are in the very darkest parts of those images. So I go through all of this in great detail in the blog entry with lots of examples that you can see how sometimes you can see stars in the background of space images and sometimes you can't. There are wonderful illustrations throughout this blog post. And I want to say you may have just helped some people buy a new flat screen TV because I bet a lot of people see that HDR, which stands for high

dynamic range, and not really known what they were talking about. Again, I really love this explanation. I'm only sorry that the people who probably most need to see it are not going to find it. And so I sure hope that anybody who does see it or hears this is going to share it with their doubting friends. I hope so too, Matt. Thank you, Emily. She is the senior editor for the Planetary Society. You can see her work, including this January 28 post at planetary.org. And while you're there, you can check out the current edition of the Planetary Report. And now on to the CEO of the Planetary Society, Bill Nye. Bill, it's my first opportunity to wish you a happy new year, at least here on the air, but also to wish you a happy end of the shutdown, we hope. Yes, happy end of the shutdown to people of the world. No, it's very good to not have a government shutdown. It had a big effect on NASA. People were not at work for over a month, which was bad because as we say, not only do the tides wait for no one, the motions of planets and cosmic bodies do not

wait for human affairs. So things kept moving through space and contractors who make instruments and rocket systems, if you shut down for a month, it's hard, it's expensive, or it's time consuming to get things running again. So actually, Matt, one of the outcomes of this, if I may judge, silly shutdown is that the U.S. Congress may pass legislation that prevents anyone in the executive branch or congressional branch or judicial branch from shutting the government down. This could be actually an unintended benefit of this recent legislative adventure. I saw that there are actually two bills, one from a Republican, one from a Democrat, which would accomplish exactly that. Sounds like a sensible move to me. Yeah. Here's the thing. If you are hired to run a corporation, you don't show up and shut the corporation down. The board of directors would

kick you out immediately. The idea is not to, unless you're going out of business, the idea is not to shut the government down. The idea is to run the government. You're the executive branch, you're the congressional branch. It is to run things, not stop them for crying out loud. But with all that said, Matt, the Planetary Society kept humming along. You know, we have a lot of members around the world, and a lot of members remain engaged with us. All our members remain engaged. And I want to thank everybody for making contributions at our end-of-the-year campaign and for continuing to support us here at the Planetary Society. If I may shut down a side.

Thank you, Bill. And I join you in that gratitude toward our members and everybody else who donated to the Society before the end of the year, which of course is something you can do any time of year. But we did have a big special effort underway and it was very successful. And thank you for leading that. Sure, it's all me. No, it's all you all out there. We are connecting you with space like never before. And thank you for leading that. Sure. It's all me. No, it's all you all out there. We are connecting you with space like never before. And you know, Matt, I was just talking to Dr. Betts, Bruce Betts here this morning, and there is a possibility that our LightSail 2 spacecraft will fly this spring. We have no control over it. The spacecraft is ready to go. The clock's running.

The batteries are charged up. We're just waiting for the word. But it will certainly, almost certainly, fly this summer. So I'm still very excited about that. It's a big event that's coming up that's possible through the support of our members. And as we like to say, members like you. So thanks for listening to Planetary Radio. Back to you, Matt. Thank you, Bill.

He is the CEO of the Planetary Society, Bill Nye the Planetary Guy, and I hope we can talk again soon. Thank you, Matt. Me too. Astrobiology. The term was first proposed by a Soviet scientist back in 1953, but most of us had never heard of it until just a couple of decades ago. Now it's a firmly established discipline. There's a good description of the field on the University of Washington website, and that's where our guest, Michael Wong, is a research associate in the school's astrobiology program. Mike studies planetary atmospheres, habitability, biosignatures, and the emergence of life. He has written a

featured article for the Planetary Society's quarterly magazine, The Planetary Report. It's titled, The Making of Life. Grappling with the emergence of life on Earth helps researchers understand how to search for it elsewhere. Mike recently joined me from the UW campus. Mike Wong, thank you very much for joining me on Planetary Radio. My pleasure. I very much enjoyed your article in The Planetary Report.

It'll be the basis of our conversation, though we may go in a few other directions over the course of this conversation. I don't know if you've heard the two big questions that our boss, the science guy, poses wherever he goes. They are, where do we come from and are we alone? And it seems like those are of big concern to you as well. Yeah, those are both very fascinating questions and the real driving force behind my scientific pursuits. Those are the types of questions that motivate me to get out of bed in the morning and actually go all the way to the office and start typing on my computer.

This seems to be getting a lot of attention. I mean, we've had a couple of shows about it recently, and we will have more. In this one, I think our discussion might lay out some of the basics, and then maybe we'll talk a little bit about the work that you have underway in an area that contributes to this. Let's start where you do in the article. I mean, we mention all the time on this show that you need two things for life. And when you have these two things, you find it pretty much everywhere. And those are, as I'm sure you know, a source of energy and water, but not just water, liquid water. Yeah. And we're finding these days that there are lots and lots of places just within our own solar system that either have liquid water right now or probably had it in quite a large abundance in the distant past. So the prospects are out there to look for life. You start just counting

all of the exoplanets that are out there and wondering about whether those have liquid water too. And the possibilities just go exponential. So it's a really exciting time to be thinking about these questions. There is an illustration in your Planetary Report article that shows what we think anyway is the liquid water on a whole bunch of different worlds. And these are really, they're pretty diverse, aren't they? Oh, yes. First of all, I should say that I can't take any credit for this diagram. This was, I believe, a joint production between Emily Laktawalla and Bob Pappalardo at JPL. So I can't take any of the artistic credit here. But yes, one of the main points that I want to get across in this article is that a lot of the

places where we suspect there's liquid water in the solar system, are on bodies that are very different from the Earth, where that water is underneath an icy crust, not exposed to an atmosphere like it is on Earth. And the big question that we want to try to answer is, are those habitable environments, and could they be inhabited? And what are the processes by which life might emerge on such a different kind of potentially habitable world? With all of these places in just one solar system, the only one we have easy access to that have liquid water, is it now considered reasonable that we're going to find liquid water on worlds throughout the galaxy, throughout the universe. Yes, I believe that it is quite possible that we are going to, within the next few decades,

find evidence for liquid water on an exoplanet. But that kind of liquid water will be the same kind as Earth. It will be on the surface of that world, and we will observe it through, the surface of that world. And we will observe it through, for instance, the way that liquid water changes the polarization of light that is bouncing off of that planet and into our telescopes, or through what's called glint, which is the way that liquid water sort of reflects light, very focused and very bright. We see glint, for instance, on the liquid methane seas of Titan. bright. We see glint, for instance, on the liquid methane seas of Titan. So we think that we have the capability or will have the capability in the near future to be able to look for glint on exoplanets once we have the capabilities to actually get reflected light from those exoplanets that are very far away. It's going to be harder to tell whether we have an exo-Europa-like situation where there is liquid water underneath

the surface of an icy crust, because right now we're mainly only sensitive to the atmospheres and soon the surfaces of extrasolar terrestrial planets. So for those that are more like our own, I'm thinking of, I'll invent the term aqua signatures as opposed to biosignatures, which I think we're going to talk about before we finish our conversation. You go on in the article to talk about early thought about how life, the genesis of life on earth, spontaneous generation. And it reminded me of an illustration from my old life science library books. And there was one that really stuck in my mind. And it was a drawing of an old rotting log with frogs and flies infesting it, coming out of it, except that the thinking was literally coming

out of it. I mean, fully formed species coming out of this other living thing. I mean, is that what they had in mind with spontaneous generation? Yeah. Basically, before people really understood how biology works, how replication works, it was thought that we see life everywhere we look on earth. It must just be popping out of nowhere. And today we know better. And it was thanks to this clever experiment by Louis Pasteur, who basically had a bunch of different flasks. These flasks had liquid water inside them, as well as the nutrients that life needs to grow. He let those flasks sit out, but he made one of the flasks have a very curved neck at the top of it so that air couldn't come inside. But the other flask, which was just as habitable, didn't.

And then he went further and broke off that curved neck of the flask that wasn't yet infected by life. Soon it was very infected by life. So he was showing that life can't just originate in a sterile but habitable environment. It needs to be seeded from somewhere else, which sort of disproved the idea of spontaneous generation. That is, we don't actually see separate origins of life here on Earth. Everything on Earth has descended from a single origin of life, as best we can tell. In connection with that, you talk about this relative of ours named Luca. Luca standsCA stands for the Last Universal Common Ancestor. And we have some vague inklings of what LUCA was like based on what are called phylogenetic studies or looking at the genomes, the instructions written in our DNA and our RNA,

and trying to backtrack what the most ancient sequences were based on what sequences are highly conserved or highly shared amongst the very disparate types of living beings here on Earth. And in this way, we can sort of get a handle on what LUCA was like and what environment it lived in. And some of the latest evidence points to a Luca that came from the deep, that lived in a hydrothermal setting near the bottom of the ocean. We've talked before on this show about this possibility that life began in one of these settings by one of these hydrothermal vents. And key to this is something you also talk about in the article, which is equilibrium, or rather the lack of it. Why is this important?

What I like to say is that every living thing needs to eat and to breathe. And we do this all the time, sometimes without thinking about it. That's how we gain our energy, basically by harnessing the disequilibrium or the imbalance in electrons between the things that we eat and the things that we breathe. When our metabolisms are powering us, what they're doing is basically transferring the electrons from the very electron-rich food that we eat to the very electron-greedy oxygen in the air that we breathe. And this is fundamentally what powers all of life on Earth, is an electron transfer. And things transfer when

there is an imbalance. There's a lot of energy in imbalance or in disequilibrium. You can think of being on your tippy toes, standing on top of a pole. You're very unbalanced. And if you were to fall, you would transfer a lot of that potential energy into kinetic energy. The same thing goes with electrons. They're transferring within us all the time, essentially falling downhill and giving us the energy that we need to live. One of the really critical things to understand about biology is it's not just that transfer. That electron transfer goes into pushing a different set of particles out of equilibrium, and those are protons within our body. So electron transfer creates the energy that is needed to pump protons across a membrane in our mitochondria,

thus creating a new imbalance in the concentration of protons outside of this membrane and inside of our membrane. These protons desperately want to relieve this disequilibrium and can do this by passing through a very intriguing molecular machine, basically a protein called ATP synthase, this then transfers that disequilibrium in protons into a disequilibrium in ATP or phosphates. ATP, you may be familiar with from your intro biology classes. You bet, yeah. Everybody knows ATP as the energy currency of life. And the way that knows ATP as the energy currency of life.

And the way that ATP acts as the energy currency of life, it is in yet another disequilibrium between its wholesome self ATP, which stands for adenosine triphosphate, which means it has three phosphate groups in this molecule, and its broken pieces, adenosine diphosphate, two phosphate groups, and a lone phosphate that's unattached. Our body works by basically transforming these imbalances into finally us. And if you really think about it, we are in a state of imbalance with the rest of our environment. We need to fuel ourselves by transforming natural imbalances around us into ourselves. And if we were to go into a state of equilibrium or a state of complete balance with everything else, we would essentially be dead. So that would not be good. So looking into the way that life works today offers us really good clues to how life might have originated in the deep past. It didn't hit me until later how important this ATP cycle was, the storage and transportation

of energy. So important to this, right, is the idea of a membrane, a barrier that has one condition on the outside and some other condition on the inside, whether it's the mitochondria, those little particles in our cells, those little bodies which may have once been independent living things, apparently. But the cell wall, and I guess to some degree, our own skin, but really you're talking about things like the cell wall here, right? Yeah, you're absolutely right. In order to have some kind of disequilibrium or imbalance, you need to be able to separate what's going on inside of life from what's going on outside of life. One way to look

at life, again, is that we are in a state of low entropy with respect to our surroundings. That's how we maintain our order and our complexity, is by separating ourselves. And that's a good thing. We should say low entropy is a very good thing. Yeah, that's right. Yeah, we all want to be low entropy. And the key to being low entropy, to maintaining our order and our complexity, is to raise the entropy of everything outside of us. That's actually really the only way to maintain low entropy inside of us over time. If we don't want to be flooded by all of the extra entropy that we are creating outside of us, we better have a membrane. You already mentioned the possibility that life began at one of these hydrothermal vents, or maybe more than one. Well, not likely, I guess, since we all are so similar.

What was it about the hydrothermal vent that contributed to this disequilibrium that was so critical to life? Yeah, that's a great question. When we're looking for places for life to emerge, in particular, for the type of metabolism that would lead to what we see in life today, we definitely want to look for disequilibria and focusing points for the specific kinds of chemical and physical disequilibria that are exhibited in life today. At the bottom of the ancient ocean, and first of all, this ancient ocean was probably full of a lot of CO2 and therefore was slightly acidic, sort of like a lightly carbonated soft drink. When this seawater dives into the ocean crust, it'll participate in a reaction with the minerals

in the ocean crust. And this reaction has a fancy name. It's called serpentinization. While I was typing about serpentinization, my little sister looked over my shoulder once and was like, serpentinization. While I was typing about serpentinization, my little sister looked over my shoulder once and was like, serpentinization, is that like a Harry Potter spell when you get turned into a serpent or a snake? And I was like, no, no, no. Serpentinization is just the chemical reaction between seawater and rock. But what happens is that it changes fundamentally the water. So when it comes back up, this water is, instead of being slightly acidic, extremely alkaline,

meaning that there is a huge pH gradient between the fluids that are coming out of this vent and the ambient seawater around it. And pH is a concentration of protons, which is exactly one of the gradients that we harness in our own cells. And furthermore, this water that is coming out of these serpentinizing vents has lots of hydrogen and methane. And relative to CO2, hydrogen and methane are very electron rich. They would love to donate their electrons to more oxidized or more electron greedy things like CO2 or perhaps other oxygen bearing compounds that were in the early ocean. So in that way, there is this what scientists call redox gradient or

gradient in electrons that is, again, what fuels all of life today. So there are these two fundamental gradients at these hydrothermal vents that are very, very similar to the gradients or disequilibria that we harness today. Are we making progress toward understanding how this fairly simple, easy to understand, fortunately, disequilibrium might have led to the formation of the complex organic molecules that were necessary for life? That's a great question, and it is a topic of ongoing research. There is a group at JPL, led by Dr. Lori Barge, working on basically simulating these hydrothermal vents.

And if you look at page 17 in the planetary report from December, I have a picture of one of her test tubes. I'm looking at it now. Yeah. Yeah. It's a chemical garden. This is a fairly simple setup here, where basically she is showing how chemical disequilibria can translate into these fabulous, low entropy, highly complex structures. These are

analogs for the hydrothermal vents. Now, instead of just having a test tube, she's got lots of more complicated lab setups where she can slowly inject analog hydrothermal fluid into a larger container. She can also inject things like organics, which will interact with the minerals and interact with each other inside of the structures that she's producing. So this is ongoing work. And it's a very exciting field that we're just scratching the surface of. And it's a very exciting field that we're just scratching the surface of. I should tell you about this dream that I had once. So I used to teach the astrobiology class when I was at Caltech. I brought Lori in every year to do a lab with us and make these little analog hydrothermal

vents that you can see here in the Planetary Report article. that you can see here in the Planetary Report article. But in my dream, I dreamt about taking my astrobiology class on a field trip to JPL, not that far away from Caltech. And in my dream at JPL, Laurie had created this huge tank that basically simulated real-life, large-scale hydrothermal vents that you would then put on a scuba diving suit on. And you would go inside this colossal tank and you would be able to

observe serpentinization vents in their full glory. Because right now it's very hard to get down to them. You can see a photograph of the lost city hydrothermal vents on page 60, on the opposite page of the article. These are at the bottom of the Atlantic Ocean, and not many expeditions to these vents have been taken. I actually don't know how many, but it's probably, you can count them on one hand. And so we know very little about the geology and the ecosystems that are actually happening down there. And we need to

learn more. We need to go back and learn more. Do you mind if I borrow that dream? I'd love to have that and do a little scuba diving around these more easily accessible hydrothermal vents. Yeah. You know, if you were to tell me, as I look at this picture of this test tube, that what I'm looking at is alive. These turquoise deposits with little filaments coming out of the tops of them. And we'll put some of these images on the show page at planetary.org slash radio on this week's show page. You can also, of course, read the planetary report online at planetary.org. And you can see all of these great illustrations and read Mike's article. If you were to tell me these were alive, I'd say, okay, I'll buy that.

Yeah, absolutely. And this just speaks to the great power of disequilibria driving complexity and orderliness in natural systems, and also to the fundamental connection between geology and mineralogy and life. I really think that it's at a place like this where you can harness not just aqueous chemistry, but also surface chemistry and catalytic chemistry from metal-bearing minerals that would have sparked something as complex and as wonderful as the first biochemistry. And indeed, I don't know if this is going on too much of a tangent, but when we look at the enzymes and the proteins that do a lot of the heavy lifting in our own cells, we see at their very core, doing a lot of the electron transfer, mineral-like structures, things that contain iron,

things that contain molybdenum, things that contain nickel. This hints at a past that was very much intertwined with the mineral world. So it's not just aqueous chemistry. It's a lot of transition metal chemistry as well happening in our very own bodies today, and probably at the origin of life itself. Well, if that's a tangent, it's a very relevant and fascinating tangent. You mentioned in the article, which I did not know, that the Mars Exploration Rover Spirit found some evidence for hydrothermal activity in the distant past, of course, on Mars. Yeah. We have evidence from rovers and I believe also remote sensing from our orbiters around Mars that are scanning Mars' surface for minerals that

Mars' surface has participated in these types of water rock reactions. Probably most of these reactions happened billions of years ago, three to four billion years ago. But Mars was a very active chemical and geochemical place. And a lot of people wonder, could early Mars have looked a lot more like Earth? And if so, could it have had a separate emergence of life? So a Martian genesis. And then, of course, you also talk about this possibility that maybe life didn't originate on earth. Maybe we're all Martians. Yes, indeed. I would have to say that this is not a hypothesis that most astrobiologists think is

likely, but there are a few strong proponents out there. One of them is Professor Joe Kirschvink at Caltech, who I was lucky enough to take a class from, and he definitely talked about this hypothesis. Joe thinks that we are all Martians, and not only that, but we are all Thartians, or coming from the Tharsis province on Mars. The reason for this, I'll just outline a few reasons briefly. Joe is a proponent of the idea that you need wet and dry cycles to facilitate the first biochemical reactions, in particular, the polymerization or the linking of building blocks for life. I should pause here and mention that that is something that is distinct from the origin of life hypotheses at hydrothermal vents, where there's obviously no drying cycles there. But if indeed you do need some wetting and drying cycles, early Mars may have been a much better place to harbor the emergence of life than early Earth.

harbor the emergence of life than early Earth, because as I mentioned in my article, the earliest part of Earth's history was probably characterized by a global ocean, one where there were very few landmasses. Mars, on the other hand, has a lot less water than Earth, or had a lot less water than Earth, even in the distant past. In particular, the Tharsis region, with these giant shield volcanoes, the largest volcanoes we know of in the solar system, would have definitely stuck above any putative ocean that was on early Mars. Volcanoes also tend to drive lightning, and they stick up high into the atmosphere where there might have been oxidants, those electron greedy things. greedy things. So a warm little pond on the edges, on the slopes of Tharsis may indeed have been a very great place to do some exciting prebiotic chemistry. And this, of course, makes me think of what Charles Darwin referred to as the warm little ponds, which before we discovered those hydrothermal vents is what a lot of people were thinking about for the genesis of life. You told

me you got to hear our recent episode where I talked to those researchers at McMaster University in Canada. Much like the work at JPL with hydrothermal vents, they're trying to simulate what might happen in these little maybe tidal pools that regularly are inundated with water and then dry out. Are you supportive of that kind of work? Does this sound interesting? Oh, absolutely. Yeah. I think that the McMaster group is doing a great job over there and I'm very excited for whatever they discover. I guess my goal with this article, I focus mainly on the alkaline hydrothermal vent theory for the emergence of life because I think that most people who are educated about the origin of life are familiar with the idea of this warm little pond, which is

still a very prevalent idea in the scientific community today. So I wanted to expose a general audience to a different origin of life hypothesis that had implications for places like Europa and Enceladus. But I absolutely think that the McMaster group and other groups around the globe who are working on warm little ponds and the chemistry that could be happening in them are doing a wonderful job. The main thing that those groups are after is looking for the first self-replicating molecule, which many people assume to be RNA because of RNA's dual capabilities as an information storage molecule and as a catalyst. Very importantly, it's known to be able to catalyze

its own creation given ample supply of building blocks. The main trouble is that it's very hard to create the very first RNA molecule from scratch. Scientists like our McMaster colleagues are seeking the mechanisms and environments by which this might have been done. And so understanding the beginnings of replication is absolutely important work in the field of astrobiology and the origins of life. And I wish them the best of luck. How about life as we don't know it? I happen to know that you're a science fiction fan, particularly a Trek fan, because in fact, you kind of abased your own webcast, Strange New Worlds, around the science of Star Trek, one of my favorite topics. Science fiction has no shortage of life as we don't know it.

that her spacecraft, if it makes it to Saturn's moon Titan, is going to be looking for prebiotic conditions on the surface of that very cold world. Can you imagine life evolving there? Oh, yeah. That's a really great question. First of all, let me say that I'm a big fan of Dragonfly and of Titan. So without going into too much detail, life on Titan would be fundamentally different from a biochemical point of view for three main reasons. One is that it's very cold, like you said. Life would need to be able to have reactions that actually proceed at those extremely cold temperatures. Two, the liquid on Titan is liquid methane, for the most part. Methane is very chemically distinct from water in that water is a polar molecule, meaning it has a slight electrical charge to it on different sides of the water molecule itself.

And this is so essential for the ways that life operates on the nanoscale. Methane, on the other hand, is nonpolar. Any biochemistry would have to work inside of that medium, and it's very hard to imagine what kind of biochemistry that would be. And finally, Titan has very little available oxygen. Oxygen is one of the four most prevalent building blocks of life on Earth. But Titan, while it has a lot of hydrogen, carbon, and nitrogen, has very, very little oxygen because it's so cold. And most of that oxygen is locked up in solid water, which forms the crust of Titan. So we'd have to imagine an alternative biochemistry that doesn't take advantage of oxygen at all. For those three reasons, life on Titan would definitely be life as we don't know it.

Let's say that someday, probably won't happen with Dragonfly, but you never know, we discover that there was a second genesis of this very different sort of life on Titan. Maybe we find evidence of some very different type of life on Mars. I think I know the answer to this, but what would this second genesis within our solar system, what would it mean for the prospect of life across the universe? There's an old saying that goes, there are only three numbers in physics, zero, one, and infinity. Since we know that the number of instances of life in the universe is not zero, it's either one or infinity. And so finding another

instance of life within our own solar system means that there's just so many possibilities out there. We're very unsure of whether life was a fluke accident or whether it's some kind of result of the way that matter and energy like to organize themselves. You can argue it either way, but until we go out there and really get a lay of land and say, look, the rest of the universe seems to be completely barren, or there are other instances of life out there and here's how they came to be. And there's some underlying principle, like for instance, the dissipation of disequilibria that drives them into existence that we will get an understanding of our place in the cosmos. Thrilling stuff, Mike. Before we close, tell us a little bit about the work that you have underway at the University

of Washington. Yeah, sure. I'm currently looking at the ways that we can actually try to find life on an exoplanet, or how we might be fooled into thinking that there's life there when those signals were actually made abiotically. So in particular, we're concerned with looking for oxygen. And oxygen is a very good biosignature, And oxygen is a very good biosignature, we think, because Earth's atmosphere is full of oxygen and all of it was created by life, in particular photosynthetic plants, algae. The question is, is there a way to create oxygen, high levels of oxygen in a planet's atmosphere without life? People have come up with different theories for this.

And one good way to create a lot of oxygen is by shattering CO2 molecules, carbon dioxide molecules, with ultraviolet light. CO2 obviously has a lot of oxygen locked inside of it. So if you break it apart, you might create molecular oxygen, O2. This could happen on planets with very thick CO2 atmospheres, such as Venus. So our neighboring planet, Venus, has about 90 times the atmospheric pressure of Earth, and most of that is CO2. And yet, Venus, although it's being bombarded by lots of ultraviolet radiation from the sun, doesn't build up abiotic oxygen. And we think this is due to the chemistry that is happening on Venus's atmosphere involving exotic species like sulfur and chlorine atoms that are floating in Venus's atmosphere that regenerate the CO2, rebuild it so that oxygen doesn't build up. And we're wondering if those mechanisms for scrubbing out oxygen and reforming CO2 actually work around other types of stars.

And the most exciting type of star right now is an M dwarf star or a very red dim star. This is the most common type of star, right? Exactly. Yeah. Most of the stars in the galaxies are M dwarfs. And we're finding planets by the bucket loads around M dwarfs, some of which are in the habitable zone. And what we don't want to do is accidentally find a Venus-like planet that has built up

a lot of oxygen through shattering by ultraviolet light and mistake that for a planet that has a biosphere that is making that oxygen. stake that for a planet that has a biosphere that is making that oxygen. I'm looking into whether or not those types of planets, Venus-like planets around M dwarfs, do or do not build up oxygen abiotically. You must be very excited, looking forward to the new generation of telescopes, the James Webb Space Telescope and the ground-based scopes, that might give us this ability to detect oxygen in the atmospheres of these exoplanets. with Dragonfly investigating the chemistry on the surface of Titan, or telescopes that will stare light years away at planets that are orbiting distant stars and get a handle on what they're made of and whether they have life. It's just so invigorating to go to work every day and realize

that we're on the cusp of an astrobiological revolution, perhaps. And that is probably a great place for us to end this very exciting and fascinating conversation. Thank revolution, perhaps. And that is probably a great place for us to end this very exciting and fascinating conversation. Thank you, Mike. Live long and prosper. Thanks. You too. Mike Wong is a research associate in the University of Washington Astrobiology Program, and he studies planetary atmospheres, habitability, biosignatures, and the emergence of life, which, of course, has dominated our conversation today. He, as I mentioned, has his own podcast you can find at Strange New Worlds about the science of Star Trek. His article in the Planetary Report, and this by the way is the Winter Solstice issue of the Planetary Report that you can find at planetary.org, is titled

The Making of Life. Grappling with the emergence of life on Earth helps researchers understand how to search for it elsewhere. On now to this week's edition of What's Up with, you know who, Bruce. Oh, Bruce, can you give me a random space fact? I'm so glad you thought of that. I always forget. Time for What's Up on Planetary Radio. The chief scientist of the Planetary Society is Bruce Betts, and he has joined us once again to tell us about the night sky. And we'll do a bunch of other fun stuff, including

giving away five more copies of First Man, that great movie about Neil Armstrong. Welcome back. Thank you. Good to be back, Matt. So we've still got the pre-dawn is where the planetary party is happening and things are shifting around relative to each other. If you pick this up soon after it comes out, then on the morning of February 1st, you will find the moon hanging out between Venus, super bright Venus, and very bright Jupiter in the pre-dawn east. If you look some other morning, you'll still see Jupiter and Venus up there looking spectacular. And yellowish Saturn, much dimmer than the other two, is below the other two, climbing and passes above Venus around February 18th. It's a party. It's a planetary party. And lonely Mars is still hanging out in the evening sky, but continues to fade and get lower in the

West. Did you see my little image of Jupiter and Venus hanging out next to the palm tree last week? Glad you brought it up. That was spectacular. And it shows not only what an amazing photographer you are with your phone, but how bright and stunning they are. But it was very nice framing with the palm tree. It was lovely. Thank you. Thank you. I had nothing else to do as I stood there freezing on the terrain platform. Well, I'm glad I could provide some planets for you to take pictures of. All right, we move on to this week in space history. We mentioned last week, I'll mention again, this was this week, the Columbia disaster occurred, seven astronauts died. We remember them. Much happier news in other areas of space. In 1958, Explorer 1 became the U.S.'s first satellite. 1961, hey, chimp, ham, suborbital flight, way to go, ham.

In 1971, Apollo 14 launched and landed on the moon. I wonder if ham is in the International Astronaut Hall of Fame. I'll have to check. I'll have to look online. Is he a member of the Association of Space Explorers? I don't know. That's a good question. Maybe he's the mascot. All right. We move on to Random Space Fact. Wow.

That was possibly the worst chimp impersonation I've ever heard. Oh, I was going to tell people I got Ham to do a celebrity intro for you. Maybe you can edit this show so that no one will know. That's what I'll do. No one will ever know. Exactly. We're going to talk against my better judgment because I still don't believe Einstein and his crazy jokes, but we're going to talk general relativity.

As you may be aware, one of the first things that general relativity explained that no one had been able to explain was the precession in Mercury's orbit. So the closest point in Mercury's elliptical orbit to the sun in purely Newtonian fun with only those two bodies would stay in the same place. Tugs of other planets and other things make that periapsis move over time, but they have this discrepancy of about 43 arc seconds per century. And it turns out general relativity in its wacky way, explain this by gravitation being mediated by the curvature of space time, or as I like to call it, general relativistic hoodoo. But here's an interesting tidbit I throw on, which I had not heard as much, but makes sense. Mercury, this general relativistic

effect is 43 arc seconds per century. Well, it happens for the other planets too. Venus, and it's been measured now for Venus at a little under nine arc seconds per century and Earth at a little under four arc seconds per century effect of general relativity on the periaps per session. There you go. There you go. Albert is up there giving you a nice little wink. He probably doesn't enjoy saying I don't believe his jokes. I love this, actually, because it's such a great story from the history of astronomy. Astronomers, I think up until basically up until Einstein, were looking for that other planet Vulcan because they couldn't figure out why Mercury was behaving the way it was. And it turned out it was just one of Albert's little pranks. All right, we move on to the trivia contest. I asked you, what 180-kilometer-diameter crater did the Chinese Chang'e 4 land in, and who is it named after? How'd you do, Matt? difficult to review all of these and to decide which ones we have time to read because we get so many great responses. The person that random.org chose this week, and that's William Fisk in Palm

Bay, Florida. First time entry. That crater that I think you're looking for is Von Karman crater. 180 kilometer crater. Yeah. Well, congratulations to you, William. Nice work. You've just made a whole bunch of people who have entered every week for ages. Very, very envious. Did he say who it was named after? Let me see if he... Yes, Theodore von Carmen considered the father of supersonic flight. There you go. I forgot that you asked for that. We're going to send William that signed copy of Alan Stern and David Grinspoon's Chasing New Horizons inside the epic first mission to Pluto, along with a full set of kick asteroid stickers from the Planetary Society and the Chop Shop store developed in collaboration with the chief scientist

who we're talking to right now. And a 200-point itelescope.net astronomy account from iTelescope, the worldwide network of telescopes that William will be able to use to, I don't know, you can check out that precession of Mercury, I suppose, if he's really, really careful. Indeed. I got a bunch more. Here's one from, I'm just going to say Vincent in San Jose, California, because indeed he says his last name is impossible for the American tongue. It's something like Nangelhelm. Nangelhelm. He said, as a lot of people pointed out, that Theodore von Karman was the PhD advisor for well, I can't do this one either, but he's the founder of the Chinese space program.

Coincidence? Chinese lander on the far side has come down in this crater. Vincent adds, now there's Karman for you. Oh, good. I wasn't sure I got that across right. Mark Sulfridge in Boise, Idaho. He says, as a Caltech alum, class of 92, von Carmen's name was very well known to me. Even prior to researching this question, I have attended several lectures in von Karman Auditorium, which I think of as

almost hallowed ground. You and us both, Mark. Von Karman Auditorium, which is, of course, at JPL. But von Karman was, I'm sure you know, he was the first director of JPL, right? One of the founders. Yeah, he started their crazy experiments in the Arroyo that eventually evolved into JPL. And indeed, and he also is a Caltech professor. Only Zoe Reinert in Germany and Thomas Hertel in Invergrove Heights, Minnesota. There's another interesting town. They said that he was also the first to explain this thing, which now is called, and I thought it was a joke at first, but I looked it up, the Karman Vortex Street. Have you ever heard of that?

No, I have not. Yeah, wiki it. It's a real phenomenon having to do with fluid dynamics and stuff that happens in a fluid when it hits a blunt body. And it makes these really pretty little vortices, and they're called the Carmen Vortex Street. I have no idea why they call them a street, but anyway, it makes real pretty pictures. Richard Hoffman in Greenport, New York, he says, I wonder if Roger Waters would mind changing the album title to Far Side of the Moon.

Wouldn't that make everything less confusing? Pink Floyd fans out there, of course. Brian Jones of Alexandria, Virginia. Boy, I have a lot of stuff today. He says Chang'e IV landed in the Aitken Basin, which is not what we were looking for, but it's true because von Kármán Crater is in the Aitken Basin. He says that was named after American astronomer Robert Aitken, who suspiciously was awarded the Bruce Medal in 1926. Explain that one, Dr. Betts. Why haven't I gotten the Bruce Medal? Oh, wait. I have it right here.

Darn, I was thinking that would be a great thing for us to give out as a planetary radio prize, the Bruce medal. But apparently it's already taken. Well, we could just say the real Bruce medal or the genuine Bruce medal or something like that. We will close with not a full poem this time. Well, you know, it's a haiku. It came from Sven Newhouse in Germany. Far side of the moon, such yearning in so few words, the unknown beckons. Oh.

We get in a haiku mood at the Planetary Society now and then. Maybe this will kick another one of those off. I know what we should kick off, which is another contest. All right. kick off, which is another contest. All right. What planetary spacecraft, and by this I mean things that are not Earth-orbiting satellites, to be clear, so something that goes beyond Earth orbit, were launched by the space shuttle? So launched by one of the space shuttles, planetary, in which case I mean not Earth-orbiting satellites. Go to planetary.org slash radio contest. I couldn't name one for you, but I definitely have heard of a couple.

You can tell us what they are. You've got until Wednesday, February 6th at 8 a.m. Pacific time to get us the answer. And you will, well, five of you will win copies of First Man, that movie biopic of Neil Armstrong, which has been nominated, I think, for a few Academy Awards. I should have checked that out since the last time we talked. And we will give someone else a set of those Kick Asteroid stickers and what the heck, a 200-point itelescope.net account. I think we're done. All right, everybody, go out there, look out the night sky, and think about what the criteria should be to win the Bruce Medal.

Thank you. Good night. I think you should have to do a really great chimp impression. Can't even do it. That's Bruce Betts. He's the chief scientist of the Planetary Society who joins us every week here for What's Up. And by the way, they're Blu-ray copies of First Man.

Ooh. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its life-affirming members. Mary Liz Bender is our associate producer. Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. I'm Matt Kaplan at Astra.