Discovering Life in Unexpected Places

Life is emerging where scientists once thought it impossible — deep beneath Earth’s surface, under crushing pressure, extreme heat, and total darkness. These discoveries are redefining the limits of biology and expanding the search for life beyond Earth, from Mars to the icy moons of distant planets.

USC Dornsife Dean James Bullock conducts a conversation with USC researcher Karen Lloyd and alumna Laurie Barge exploring how Earth’s most extreme environments are shaping where — and how —scientists search for life beyond Earth, and what these findings reveal about life’s origins and why it matters for humanity’s future.

Featuring:
Laurie Barge, PhD ’09, senior research scientist in astrobiology, NASA Jet Propulsion Laboratory (tentative)

Karen G. Lloyd, professor of earth sciences; Wrigley Chair in Environmental Studies, USC Dornsife; author, Intraterrestrials: Discovering the Strangest Life on Earth

Learn more about the Dornsife Dialogues and sign up for the next live event here. 

Transcript

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Unknown

Welcome to the podcast version of Dornsife Dialogs hosted by the USC Dornsife College of Letters, Arts and Sciences.

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Conversations feature our distinguished scholars, alumni, and other thought leaders discussing the fascinating issues that matter to you. You can also find video recordings of these discussions on the USC Dornsife YouTube channel. We begin this Dornsife dialog with an introduction from Dean James Bullock

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Unknown

Hi, everybody. It's so fun to be here with you today talking about the topic that's going to be,

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incredibly interesting, discovering life in unexpected places and figuring out what that might mean for life elsewhere, beyond the Earth.

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Unknown

I'm very excited to introduce our speakers today, our panelists.

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Two people who have connections with USC Dornsife are really proud of.

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So let me start with

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Lori Barge, who is a senior research scientist at NASA's Jet Propulsion Laboratory, and she co-leads the JPL Origins and Habitability Laboratory. Her activities are numerous, including. She's the high rise investigation scientist on NASA's Mars Reconnaissance Orbiter. She's the co-founder and co-chair of the board of directors

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of the Scientific Society for astrobiology, and she's a member of a number of important panels, including the National Academies Panel on Astrobiology, a science strategy for the Human Exploration of Mars.

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She received

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her B.S. in Astronomy and Astrophysics from Villanova University. Her PhD in geological sciences from USC Dornsife.

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held postdoctoral positions at

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Caltech and holds many awards, including the JPL Lew Allen Award for leadership, a NASA early career public achievement Medal, and a Presidential Early Career Award for Scientists and Engineers. Our other panelists, Karen Lloyd, is a professor of earth sciences,

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and the Wrigley Chair of Environmental Studies at Dornsife USC.

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She's also the author of a book that came out in May of 2025 called Intra Terrestrials Discovering the Strange Life on Earth.

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This book has already been longlisted for the Wilson Award for Science Writing, and it's something that's already on my to read list, and hopefully we'll get into a little bit of that today. She holds a BA in biochemistry from Swarthmore and a PhD in marine sciences from the University of North Carolina.

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Unknown

She's held postdoctoral positions at Rice University in Denmark, and formerly she was a professor of microbiology at the University of Tennessee, which she held until 2024. And so we thankfully were able to convince her to move out here to USC and take the Wrigley chair of Environmental Studies, which she holds now. She's the author of,

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more than 100 scientific publications.

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She's given two Ted talks, which collectively have been viewed 5 million times. She's a Sloan research fellow at NASA. Early career fellow, a Simons Early Career fellow in the National Academy of Sciences, Kavli fellow. So we have two esteemed folks here today. So thank you to Lori and Karen for being here. And before we begin the conversation, I just want to ask each of you to just in your own words, talk about what you're most excited about, what you do in your labs right now.

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Unknown

So, Lori, why don't you. Why don't you kick us off? Tell us a little bit about what you do in your lab and what you're excited about. Sure. So I am a research scientist at the NASA's Jet Propulsion Lab. And so I co-lead the origins and Habitability lab, in which we, we are trying to understand how life started on Earth, and also, in general, how life could start anywhere.

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Unknown

And what it means to look for life on other worlds. And so I'm really interested in, kind of how, how different reactions of organic chemicals can occur on different planets, including early Earth. But also Mars, the ocean worlds, which are these moons of the outer planets like Jupiter and Saturn, that have oceans under their icy shells and might actually have hydrothermal vent activity similar to some of the sites we see on Earth.

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Unknown

And so in my lab, we do a lot of work where we grow hydrothermal chimneys. And lab chimneys are these things that form events, and minerals come up and plumes come out on the seafloor. These are fascinating habitats for life on Earth, and we grow these in the lab. So that way we can get hydrothermal chimneys, you know, in our hands, it's really hard to go to the sea and get them from the seafloor.

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Unknown

But we can grow them in lab and we can grow ones that are similar to other worlds, not just Earth. So as far as what I'm really excited about at the moment, I want to know how common or rare is life. And we know there's life on Earth and it's very diverse, but it originated and all of our life is related on this planet.

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Unknown

And so is it possible to have origin of life on Mars or on Saturn's moons? And so one thing I'm really excited about working on is for the organics that have been found on Saturn's moon Enceladus. Is it possible that those are from an origin of life? Not necessarily life, but what if we're witnessing an origin of life in real time?

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Unknown

And so some of the work that we're doing is trying to understand how those molecules might form in a non-biological sense, but maybe we're going to witness something cool that we can't see on Earth today, because there's life everywhere now. So that's just a quick summary of what I'm into at the moment. Fantastic. Wow. Well, speaking of the diversity of life on Earth, Karen, why don't you tell us a little bit about what you're excited about and what you do in your lab here at USC?

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Unknown

Yeah, pretty much everything I do is focused on looking for life inside planets and planetary bodies. So, right now, the one that I have the best access to is Earth. So that's what I study. But we go broadly across Earth. We work underneath the oceans. We work in the high Arctic areas. We work in permafrost. We work in we use hot springs as sort of like passive sampling ports where you get the deep subsurface biosphere brought up for free, and you can sample all around a bunch of different ones.

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Unknown

And just to get an idea of to answer these general questions of like, who in the world is down there? What are they like? What are they eating? What are they doing for earth systems? How do we detect them? Just what makes them tick? Because what we've been discovering over the past, you know, a few decades, is that life inside Earth is pretty different than life on the surface of Earth in some fundamental ways.

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Unknown

Wow. That's fascinating. I can't wait to talk more about that, given sort of the context of what we're talking about. We we talking about life.

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Unknown

Lori, maybe I can ask you, you know, as an astrobiologist,

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what do we mean, actually, by the word life? And we say it, is it worth defining life? And then maybe a little bit more about the classes of life that we know about on Earth, etc.?

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Unknown

Well, so this is actually a complicated question because life is it's kind of it's funny because we know it, but it's hard to define exactly what it is in a way that you can say, this detection I made is life versus not life. So there's different definitions actually from different fields, and they really are for different purposes. So I think this is this is okay.

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Unknown

So for example at NASA the definition of life is a self-sustaining chemical system capable of Darwinian evolution. Okay. But what does that mean. Like what is a self-sustaining chemical system? And then, you know, biology textbooks, for example, may define life as having a set of certain properties, things like, order response to stimuli, metabolism and so forth. Although, of course, abiotic systems and especially prebiotic systems might also exhibit 1 or 2 of these properties.

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Unknown

So is it is it exclusive to life? Probably not. And so when we're looking for life, we sort of have to define, you know, what are the metrics that you could pursue instrumentally, like with a mission where you could say, this detection looks like life, but this one does not. But there's different purposes. And so that's why there's different definitions in different fields.

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Unknown

Interesting. So Karen, do you want to respond to that?

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Unknown

what do you think about the definition of like or are you concerned about that question or are you just. Yeah, I mean, I think it's an interesting question. And I mean, I completely agree with what Lori said. You know, you you can define it how you need it in the moment because it's you can find a counterexample to almost every

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Unknown

metric that you want to say has to be there for life.

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Unknown

I mean, there are some things that we, we know that life needs that are not unique to life, like life has to have an energy source like that is for absolute certain. And that's sort of one of the things that I just, I find fascinating how how does given that requirement, how far can life push it to use that in interesting and weird ways, and maybe down to like the bare minimum energy that it's necessary to run life?

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Unknown

Let's go with that. The energy question a little bit and maybe, again, Lori, talk to me about what's autotrophic, what's heterotrophic, and how do we think about that in terms of, you know, life more generally? Yeah. So that life has a lot of ways it can it can get energy from the environment. I mean, there's a whole wide variety of metabolisms that life does.

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Unknown

And those have evolved over Earth's history of 4 billion years. And so there's two main types. There's autotrophic, which is where life makes its own organics. And it takes carbon from the geological system. Things like, say carbon dioxide. And then life makes its own organics from that. And then there's heterotrophs where life will use organics that it has, and then it will break those down for energy.

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Unknown

So generally the organics heterotrophs use are made by the autotrophs. This is similar to how, you know, photosynthesis is the base of the food chain. And then it makes plants. And then heterotrophs like us can eat that. But one of the big questions for early life on Earth, and also the origin of life, is what sort of energy mechanisms were the first?

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Unknown

And what does that mean? Because certain metabolisms evolve later than others. And so how do we know what life was like at the beginning? And for the even before it was really called life, what energy metabolism or system was it using? Like was it breaking down organics that were present, say, from meteorites? Was it making its own organics from, say, a hydrothermal event?

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Unknown

And this was one of the things that we're really interested in studying. So let me ask you about that because like let's let's get down to the origin here. I mean, how quickly did it happen on Earth do we think do we even know it's should it happen that quickly in other kinds of environments? What do we know about that?

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Unknown

How long did it take for some kind of life to happen here? Well, so this is actually one of the bigger questions in, in geo biology is when exactly was the earliest life on Earth. And it's, it was early. So it was like for say 4 billion years ago. And so whether or not that that means that life would have started at that same time on another world that we don't know, because we don't really know what led to the origin of life on Earth.

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Unknown

There's been a lot of progress in the field, but we don't know exactly how long it took or what was required for it to initiate. And so it sounds like it happened quickly. Right? It's like Earth formed. And then we had oceans and things, and then pretty quickly it seems like there's life. But that's a geological term really, because it's still millions of years.

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Unknown

And so when you're talking about geological time versus, you know, human time, if we're going to look at, say, someone's lab career. Yeah. Can we actually do the origin of life in the lab? Even though that is difficult in lab, it doesn't mean it took a very, very long time geologically. And reconciling these two kind of timescales is is a challenge for the field.

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Unknown

But how do you know how long it would take on another world that we can't really say, because we only have one example, really, to compare it to. Can I ask, can I ask something of Lori? There's something that's always bugged me about the origin of life, because when we know about, like, everything we know that's alive right now, every like 100%, no exceptions.

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Unknown

Everybody's got DNA, and we all have DNA that matches well enough so that we know we're all none of us had a different origin than others of us. So why? Why do we not have multiple origin stories? Because I kind of get that. Maybe they're not. Maybe we're not getting origin of life happening now because there's so many of us around now.

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Unknown

We'll just eat it every time it gets going. But back then, like, you know what? We know about biology is that we tend to get like multiple things going at once and then like some get bigger than the others and whatever. But everybody kind of coexists and we have diversity. Why do we not have diversity of origins? That's a great question.

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Unknown

And so this is something we we wonder about a lot. And it does. So the whole life tree of life on Earth came from one common ancestor. But that doesn't mean that that was the only origin of life. It means it's the only common ancestor of life on Earth. So it's totally possible that in the prebiotic world, there would have been multiple places where what we would call origin of life might be occurring.

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Unknown

It's possible that only one of them really made it. It's possible that multiple did. But then there was some time in between what we say origin of life on the planet and the common ancestor of our tree of life. So there was other life there. There was, you know, other ancestors that are now extinct. There were other types of life that might have been different.

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Unknown

Maybe. We don't really know. And so it's that is that distance really between the prebiotic chemistry, the origin of life and what we call the last universal common ancestor. We call it Luca of life on Earth. So it is possible to imagine another world that you could have two origins of life or two roots of a tree of life.

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Unknown

So that's this is also why it's super important for origin of life to study the life that we have today, to kind of understand, like what makes all of life have common properties. And what does that really mean for what it would have looked like in the beginning? And what could you consider alternative timescales like? I know you do a lot of work with life on Earth.

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Unknown

I wonder if you thought about if you rewind the clock of Earth history all the way to the beginning, and then you start it again? How much would it look like, what we have now versus how much might be different? Yeah, no, I do a lot. And that's actually like I wanted to say. So do you think that like, it's possible that some of these micro microbial fossils that we see in rocks that we know are really ancient because we can date the rocks?

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Unknown

Do you think it's possible that some of them did not have DNA, but they were life like they were in a separate origin, I don't know, and that's as I can't really say because it's not certainly my field, but it is. I mean, it's interesting to imagine, but the thing is, we have so few examples of fossils from these really early days of Earth anyway, and we don't really have any rock record of the prebiotic world.

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Unknown

And so unfortunately, it's just one of those things we can't know from, say, geological studies, but we can try to recapitulate it in the lab. So that's a that's one thing I try to do is can we make this happen in lab to at least understand what was possible? So interesting. So, so can you tell us a little bit, you know, we talked about common ancestor, but then in terms of the variety of life that we see on Earth today, I guess what you're finding is it's staggeringly broad and kind of weird and totally unexpected.

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Unknown

Start telling the story of the kinds of things you, you know, you have discovered and your colleagues have discovered over the last even couple decades about how diverse life is. Yeah, we didn't we didn't know we were going to find this stuff. I mean, this is this is like, maybe that's true of every discovery. That's what makes it a discovery.

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Unknown

But what we did in the early 2000s, late 1990s is that we got a new tool, we got a new way of looking at the microbial world, and that was the ability to take DNA sequences directly from the environment. And so at that time, microbiology was a flourishing field. Like we have tons of isolates. We know from that that they're very evolutionarily divergent from each other.

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Unknown

And they do fantastic things, like they live in boiling water and they live at the bottom of the ocean. We knew all that going into this. And they eat lots of different things. They do lots of different chemistries, stuff that would, you know, challenge any animal to be able to do. And they could do it. We knew all that.

00:15:14:19 - 00:15:36:23

Unknown

So when I, as a graduate student and many people like me, started using this new tool to go out into deep sea hydrothermal vents or methane seats or wherever we were working, and we thought, there's this umbrella of all this diverse life which among them are out there. I felt like I had the the choices from which to choose to discover what was happening within that.

00:15:37:01 - 00:16:03:09

Unknown

And then what I caught was like outside of the umbrella entirely, like we had the wrong umbrella, the whole the, the life that's out there living, especially in the subsurface environments. I mean, that's although it's not exclusive to the subsurface. We're novel phyla. And so if you remember any of your taxonomy stuff from from biology classes of phylum is a taxonomic group that is equivalent to all vertebrates.

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Unknown

So like everything with a spine is in a single phylum. So what we are discovering is tens of new phyla. New phyla. I mean, we discovered a couple of new phyla just the other day. My student walked in and was like, yeah, I've got a couple of new phyla. It's they're everywhere. So that means that these deep branches linking back to what Laurie was talking about with deep time, like there was a lot more going on right after the Late Heavy Bombardment, you know, like when when Earth was getting getting to be and look like Earth.

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Unknown

There were things branching off of whoever got going from that origin really early on, and they've never merged back again, and they've just been here the whole time doing their little successful thing, but in a way that we couldn't detect until like 20 years ago. Do you suspect that that's most most of that was going on in the subsurface or and let me, let me sort of kind of piggyback on where I'm going with this.

00:16:59:15 - 00:17:21:12

Unknown

You know, as an astronomer, one of the things we're trying to figure out how to do over the next decade is look for signs of life as atmospheric signatures, because that's just something we can do. We can measure absorption lines and look for things like oxygen and other biomarkers, etc.. But what you're talking about, I think, is at least for some of that, certainly what you study is stuff that's subsurface.

00:17:21:12 - 00:17:45:23

Unknown

It might not have any effect on the atmosphere. How do you think about that? I mean, what do you think? Could you imagine it being like early on and I would never say that anything in the subsurface has no effect on the atmosphere. Okay. That's the thing. I mean, life is messy and life breathes. And like one of the things that at least life on earth breathes a lot of are things like methane and CO2 and hydrogen, and these are easily volatile substances, not CO2 as much.

00:17:45:23 - 00:18:05:10

Unknown

But, you know, these are things that get up in our atmosphere. So. Right. What our current atmosphere, the composition of it is actually utterly dependent upon these subsurface organisms because not only are they making the methane, they're also drawing down the carbon that if it were out in the air, would just recombine with the oxygen and we would have nothing left over to breathe.

00:18:05:13 - 00:18:26:12

Unknown

So the fact that their bodies are down there sort of helping us sequester the carbon is why we have oxygen left over to breathe. So I think that the subsurface life, even though you can't, like, spy them easily, just like staring at the surface of the earth, they do leave a signature. They leave a huge signature that you can see with spectral lines from a Kepler mission, for instance.

00:18:26:14 - 00:18:43:11

Unknown

Laurie. Take that and run with it, because I know this is when they go back to space. Yeah, yeah. Well, and, you know, I studied more a little closer, a little closer to home in the solar system. And so it's hard enough when you are on Earth trying to find out if your rock has life and you have your whole lab.

00:18:43:14 - 00:18:59:04

Unknown

Even then, it's a challenge. And then it's hard when you go to say, Mars or heaven forbid, one of these ocean worlds where you have to get through the ice shell to be able to sample things, but then you've got the exoplanets where you're never I mean, you can't physically go, but you can actually look at spectra from these distant stars and planets.

00:18:59:06 - 00:19:22:06

Unknown

So there's this whole field called biosignatures where we're trying to figure out, you know, what are actual things you could measure, like really specific things you could use a lab instrument to measure. And what would that tell you about whether or not you think you have life on that planet or in that sample or something like this? And so this is why I say, you know, the definition of life is tricky because you need a framework in order to actually do anything.

00:19:22:06 - 00:19:51:21

Unknown

So it's one thing to be philosophical, but it's another to say, I need to have my spectrometer detect whether or not an organic is present, but which organic, and what signal will that give you, and what concentration must it be at? And and so on and so on and so on. And so there's been a lot of work, actually, from the astrobiology community of trying to define these sets of measurements that are required or at least desired things like, you know, are there patterns of isotopes that look like they might be biological or is there a, energy generation or consumption that might look like metabolism?

00:19:51:21 - 00:20:10:19

Unknown

Or is there a molecule that looks like an informational polymer and things like that? But then even if you did detect it and so this is there's kind of two lines of inquiry that go on in parallel. I think in astrobiology one is trying to detect things, which is hard enough. I mean, missions are a lot of work, but then you also have even if you detect it, how do you know what it is?

00:20:10:19 - 00:20:33:00

Unknown

And so is the signal. What you think it is, is your peaks identified properly? Do you know that it came from, let's say, this thing and not a mineral reaction and not some other organic chemistry that's not Earthlike and you didn't recognize it. And so these two things go on simultaneously. And so even sometimes, you know, decades after a mission is over and the data is done, we're still thinking, wait, we have a new interpretation of what that actually meant.

00:20:33:02 - 00:20:50:13

Unknown

And then you can use that to design the process for next time. So it's just a constant iterative process. And we do learn a lot from the studies of early Earth as well. Because, you know, it is it is not easy even when you're on our planet as Charon is. Yeah. It's hard. Like, can I bring up a word that you just said, Lori, that I think is so good?

00:20:50:13 - 00:21:09:13

Unknown

It's like a little bit of a jargony word, but I want to highlight this for people because I think it's so cool, the informational biomolecule, like, you know, we talk about, like in astrobiology, we're like, oh, the informational polyp polymer is what we'll we'll say a lot of times that's DNA, but it's not. But we don't want to presume and you can correct me if I'm wrong, Lori, about my definition of this.

00:21:09:13 - 00:21:29:08

Unknown

But like we we have this sort of belief or hope that everything has some kind of polymer repeating monomer thing that is an information molecule. So instead of pigeonholing us into Earth centric view of the world and saying DNA, we tend to say like informational biopolymer, which I think is kind of a funny thing that we do, but it's useful.

00:21:29:08 - 00:21:43:04

Unknown

Yeah, a lot of this is you know, life as we know it, and life is we don't know it. So life is we don't know it. You'll hear that sometimes in astrobiology, because even, you know, you can try really hard to detect an Earth like life, but like what if what if it had a different thing instead of DNA?

00:21:43:04 - 00:22:02:04

Unknown

Or what if the DNA was different? Or what if the amino acids and its proteins were a different set and so on? How different can you be and still be life at all? And there's a whole bunch of people working on this too. Let's turn back to the different life that we know about. And I you know, Karen, I see your book title there in the background.

00:22:02:06 - 00:22:24:18

Unknown

Could I ask you to share 1 or 2 of the most extreme, unexpected kinds of life that that you've encountered to tell us that story or a couple of those stories? Oh. Which story? There's so many. It's I've definitely gone to enough places where things should not be alive and found things to be alive that I would no longer say, even Mars, I just cannot.

00:22:24:20 - 00:22:45:01

Unknown

I look at that thing and I see microbes everywhere. But, I was recently off the coast of Guam, studying some mud volcanoes in 3500m. Water depths. It's very deep water. And we installed boreholes there in 2016. So we went back. Boreholes are big holes just in the ground and these went down 100m into the sediment. So these are very difficult to drill.

00:22:45:03 - 00:23:02:07

Unknown

And we were sampling fluid from them and we brought the fluid back up onto the ship and we stuck it in our meters and it was 12.7. And that that's you know, it's that pH. It's very basic. Can you think, oh my gosh, that's probably as bad as bleach. Well, we didn't really know what the pH of bleach was.

00:23:02:07 - 00:23:24:14

Unknown

So we went to the housekeepers on the ship and asked them for some bleach. And then we put that in our meters and it was only nine. So we were we were like three order, three and a half orders of magnitude more basic than bleach. And even there we find things that are alive. In fact, the thing that we found that was alive as far as we can tell, it's called Wpa2.

00:23:24:14 - 00:23:44:07

Unknown

It's a terrible name. I'm sorry about that, but that's what it's called. And it was first discovered by Ken Nielsen, who is professor emeritus in my department here at USC of our Sciences. Oh, that. Well, I love that. Lori, I think you also have a connection to Ken Nielsen. Yes, I do, he was my PhD advisor at USC.

00:23:44:09 - 00:24:03:18

Unknown

It's all it's all a big family here, so that's cool. So, Karen, let me go back to you with another thing that I think I was learning about from your book. Which is you've discovered life that you think can survive for hundreds, maybe thousands and thousands of years. Yeah. Tell us about that. That's so that's really hard to prove.

00:24:03:22 - 00:24:22:12

Unknown

Okay, this comes with a massive caveat that I've never run an experiment for a thousand years. So. Okay, we always have to allow this could be wrong. But what what we know is that we can look at marine sediments. So just like the muck underneath the oceans that probably most people have never even thought about, because why would you?

00:24:22:16 - 00:24:40:22

Unknown

But it's formed by the slow rain of all this crud from the oceans. And so from this we can, when we drill down, we're looking at a record of what got piled up for like thousands of years previously, sometimes millions of years previously. And we can date all that stuff. So we know the rate at which that stuff was piling up.

00:24:41:04 - 00:25:06:12

Unknown

And then we can measure the rate of disappearance of some chemicals as as they piled up from that, we can just do it's really super basic chemistry to calculate the total amount of energy and more importantly, the time over which that energy was delivered to this community and how quickly they were breathing. So we can actually calculate how much total power is available to this community.

00:25:06:12 - 00:25:36:20

Unknown

And we know how many cells are there. And when we calculate out this is actually work done at USC as well by, my former colleague, John Almond, who passed away a couple of years ago. So they found that this, the amount of power that is flowing into which is work over time, I'm sorry, energy over time that's flowing into the cells is about four orders of magnitude lower than the experimentally determined lowest amount of energy necessary to keep things alive, not actively growing in a laboratory setting.

00:25:36:22 - 00:26:04:23

Unknown

So what this means is that it's far, far less than what we would ever have thought could support life at all, much less the ability to, like, make two cells and divide. So now certainly somebody is dividing them. I'm not going to say like there's no cell that's undergoing cell division, but like it is possible that the vast majority of these cells are not actually undergoing mitosis and cell division and separation and all that stuff that we study pretty well in microbiology.

00:26:05:01 - 00:26:25:17

Unknown

Instead, they're just keeping that cell intact and maintaining themselves, kind of like we do over 100 years. You know, we work out, we try to eat right. We maintain our cells. They just probably do it for a million years. Wow, that's so cool. You know, you mentioned Mars, and I'm going to sort of, sort of naively say.

00:26:25:19 - 00:26:44:23

Unknown

But the one thing that we know, that's at least not on the surface of Mars because of the lack of atmospheric pressure, is just liquid water. You know, there's not like a puddle of water, at least on the surface, as far as I know. It could be wrong or it can correct me. What do we know about the requirements for water?

00:26:44:23 - 00:27:08:00

Unknown

I mean, don't we need liquid water at least for life? Or am I in my misinformed? Either of you can take that and correct me. Well, I can say we we often will say, you know, some one of the requirements for life is liquid water. But of course, you know, life lives in ice. It lives in very low water activity environments like brines and so, I mean, it's sort of life is just so diverse now.

00:27:08:00 - 00:27:20:14

Unknown

And it can do all kinds of crazy things. And so it's like any requirement we think we have, there will be some, some research on Earth who says, oh, but I found a microbe over here that doesn't seem to need that thing. And so it's always like, whoa, okay, so how do you how do you look for life?

00:27:20:18 - 00:27:35:16

Unknown

But do you, do you design your whole mission, though, to look for the one super rare weird thing? Or like all of the life that most likely need some other thing? It's just it's very complicated. Yeah, because it's not like you can change your mind once you've launched that rover to Mars, right?

00:27:35:18 - 00:27:53:11

Unknown

since you're speaking now about Mars and, but you also talked about, you know, maybe ocean worlds or subs, if you could go to one place in our solar system, you, you know, if we could create a rocket and put you in a spaceship and give you all the equipment and go look, would you rather go to Mars?

00:27:53:11 - 00:28:07:09

Unknown

Would you rather go to Europa? Where would you want to go? And then talk about why? You know, usually when I get asked that, people mean where would you send your robot? But if I was meet you and I could actually go, I would go to Mars because I just want to, like, walk around and dig around and look for stuff.

00:28:07:09 - 00:28:21:19

Unknown

I mean, it would be just so cool to be able to go on a real hike and just like, look at everything. I mean, you can see so much on earth and like, I would just love to do that on Mars. Okay. Karen, I'm going to ask you, even though I know you said you love to study stuff under the surface, but this is the planet.

00:28:21:19 - 00:28:42:07

Unknown

You've got. Do you have any? If you could go anywhere and look under the surface of Europa, Europa, Europa. Okay. Go in there. Yeah, I would go with a, hot nose mole and drill through that stuff. And, I don't know, drilling through what is it like 100km of ice? Oh my gosh, I drill a fair amount and that's that's hard.

00:28:42:07 - 00:28:59:09

Unknown

I don't know how to do that, but if I could, if I could somehow figure out how to drill, I just imagine that splitting the ocean up there is just teeming with life. And I just imagine it like that. Why not? Yeah. So let me just pause for a second here. We're going to open this up to questions, from anybody who's watching.

00:28:59:09 - 00:28:59:14

Unknown

So

00:28:59:17 - 00:29:01:01

Unknown

please feel free to,

00:29:01:03 - 00:29:04:23

Unknown

submit questions to the Q&A box and we'll get to those pretty soon.

00:29:05:01 - 00:29:10:03

Unknown

let me just go back, and talk a little bit more about,

00:29:10:05 - 00:29:11:09

Unknown

extremophiles.

00:29:11:12 - 00:29:18:11

Unknown

You know, it's something that people talk a lot about. We've gotten questions beforehand, even people want to know about,

00:29:18:13 - 00:29:21:06

Unknown

tardigrades, like, people have heard of those.

00:29:21:06 - 00:29:31:10

Unknown

maybe Karen talk to me. About what? What kind of extremophiles are you most excited about? And make your case for the, the, you know, your area of study and why it's so cool and interesting

00:29:31:10 - 00:29:39:08

Unknown

what's something you like a lot like a an extreme form of life that you've studied or know about, that you, just for whatever reason, is like your favorite?

00:29:39:10 - 00:29:58:04

Unknown

Well, I do not have favorites. They're all my children. Not that I love very much. I there is this group called the Asgard archaea, which are probably grabbing me the most at the moment. They seem to be, you know, we know that the eukaryotes are branch on the tree of life is pretty complicated, you know, as opposed to the prokaryotes.

00:29:58:08 - 00:30:13:21

Unknown

But we've never known who that host cell was who turned into modern day eukaryotes and slow that down for me a little bit. Yeah. It's like what's what do you mean by eukaryote and what do you mean by host cell and all that stuff. Tell us about the big. Sorry. I'm just realizing this answer may be too long, but.

00:30:13:22 - 00:30:35:22

Unknown

Oh, no, it's good. Let's go. This is our branch on the tree of life that includes everything you can hug. So, everything that you know and love in your life is, as a eukaryote, trees, fungi. If you love those, I do mushrooms. All the sponges and, giraffes. Everything is is a eukaryote. But. And then bacteria, like the, you know, strep throat.

00:30:35:22 - 00:30:59:08

Unknown

That is a prokaryote. So we know that the eukaryotes formed by getting a mitochondria inside them in the mitochondria was definitely in alpha proteobacteria. We know that for certain. That's what it was. But we don't know who the mama cell was that took up. However, they did that original alpha proteobacteria that became the mitochondria and turned into our entire branch on the tree of life that allowed multicellularity to evolve.

00:30:59:13 - 00:31:34:10

Unknown

And so with this subsurface work that we've been doing, we discovered a group of archaea, of these prokaryotes that evolutionarily don't really fit well with the archaea. And if you put us into these family trees, we branch out of them. So they are our progenitors. They are the direct descendants of our ancestors. And that group is fascinating. They have a things that we don't expect prokaryotes to have.

00:31:34:10 - 00:31:39:13

Unknown

They look a little bit more like us. Wow. Okay, that's really cool.

00:31:39:18 - 00:31:41:22

Unknown

I'm going to jump off since you said us.

00:31:42:04 - 00:31:59:23

Unknown

One of the things that's kind of interesting about us, meaning Homo sapiens sapiens, is that, like, we can build telescopes and spaceships and send signals across the galaxy. What does the search for life say, Laura?

00:31:59:23 - 00:32:25:22

Unknown

In the solar system, we're at least we're pretty sure we don't have ETS hanging out. But there might be microbes. How does that question, and let's say we were to discover something, you know, microbial in Europa or evidence on Mars. How would that discovery affect sort of this question that I was asking about around ate and sort of communicating civilizations like, are they connected at all?

00:32:25:22 - 00:32:44:08

Unknown

Like, how do you think about that question? Well, it's interesting because like, you're right, most when we talk about the solar system, we're looking at probably microbes if we're going to find anything at all. And so but of course, Earth was mostly microbes for most of its history. And so and, you know, still I don't know what the biomass with microbes is carrying.

00:32:44:08 - 00:33:01:19

Unknown

Maybe, you know, like it's it's a lot, a lot flat. I mean, I think it's fair to say that, you know, what's life mostly like. It's microbes. And so if we find a microbe somewhere else or if we found some other kind of life, actually, for me, the real point of that, though, is that it had an origin of life.

00:33:01:19 - 00:33:17:22

Unknown

Right? And so if we find a second origin of life, that would be astounding, because it would tell us a lot about how common or rare it is for life to begin. So I think earlier Karen was saying something about, you know, all the different places life can live. And it's and yes, if you put life on other planets, maybe you could find one that could live there too.

00:33:17:22 - 00:33:41:19

Unknown

Life is very, very diverse. But that's called habitability, which is the term for like, could life live in a place? If it was there, could it survive those conditions? And there's lots and lots of habitable environments out there, but that's a different thing than an environment where the origin of life can happen. And so if you look at a planet and we say, yeah, this looks pretty habitable, we could imagine life not dying if it was here, but can you imagine life starting there?

00:33:41:19 - 00:34:00:23

Unknown

And that's a whole other question. So if we found life, let's say on Mars or Europa or some other place, that would really excite me, because then we would know that there was another origin of life. And if the world was not as Earthlike, like if it happened on an icy moon, or there's no land and no atmosphere, well, now we know the origin of life can happen without land, without an atmosphere.

00:34:01:02 - 00:34:21:08

Unknown

That really is exciting because it might tell us more about how life started on our planet, but it also might imply that there's more than one option, which then really opens up the universe for looking for other types of things. Yeah. Wow. That's cool. So I'm sort of seeing some of the questions that that had come up before, and I'm going to ask one of them now and kind of kick it back to Karen.

00:34:21:08 - 00:34:43:03

Unknown

I know I've asked you about this a few different ways, but for you and you've described 1 or 2, but can you give us another unexpected or unique environment where life exists? Another example. Sure. I go all day. What do you want? Whatever you tell me. I'm working. I've been working recently in some permafrost in Siberia. Which I currently cannot go to for geopolitical reasons.

00:34:43:03 - 00:35:00:07

Unknown

I want to say that that, like, a lot of our exploration of Earth is very limited by what what we're allowed to do based on people who are fighting at the surface. But my Russian colleagues are fantastic, and I keep working with them. And what we find is, Siberia has the oldest permafrost on Earth. It's been the oldest.

00:35:00:07 - 00:35:19:08

Unknown

Permafrost is about 1 million to 3 million years old. And the cool thing about permafrost is that, you know, if it's thawed during its lifetime, because you'll see ice wedges forming within it. And so if you have pristine permafrost that has never been thawed, you can tell by how it looks, which is a I mean, that's a gift to know the history of something.

00:35:19:13 - 00:35:39:04

Unknown

So we have some marine permafrost that's 120,000 years old in Siberia. And what we're finding there, this is also a collaboration with one of my Chinese colleagues, is that there are these Asgard, this group I was just talking about that's like our progenitors that we generally only find in marine systems that seem to have survived over this time.

00:35:39:04 - 00:36:02:23

Unknown

We can do a lot of tests to see that the cells are intact, that they are, you know, maintaining their quality of their DNA and their biomolecules. So they seem to have survived and it's been frozen continuously. They've never thawed during the past 120,000 years, and they haven't died. And we can do calculations to see how quickly their DNA would degrade if they were just, like, dead the whole time, and they would be falling apart.

00:36:02:23 - 00:36:26:09

Unknown

So they've been hanging out for 120,000 years in frozen permafrost. And the only liquid water that's around are the brine veins that are about, you know, just a few microns in diameter, which is a it's a little bit bigger than the size of the cell. So somehow their environment is -eight degrees Celsius. One little cell with like a thin little layer of water around it.

00:36:26:11 - 00:36:53:22

Unknown

And it's just been chewing and eating and living and breathing and doing its thing for 120,000 years. Amazing. My gosh. And this relates a little bit to one of the questions that's popped up. From, I guess a questioner, which is imagine we took some microbes that you found that were extremely, I don't know, conditions that were sort of like Mars ish, and we were put them on Mars.

00:36:53:22 - 00:37:24:09

Unknown

Could you imagine that? They would survive? I guess the question is like, if we went there and sort of purposefully tried to put life there and see if it could be habitable there, could you imagine that that working? Well, I'm not a microbiologist, but I think about this sometimes, and it seems like there are certain environments on Mars where it seems really likely that you could, if you really tried, and then even even the other more extreme environments like what Karen just described sounds pretty Mars like with all the, you know, soil and ice down there.

00:37:24:09 - 00:37:45:02

Unknown

And like, if you took the right extremophile and cultivated it properly, I kind of don't see why not. But Karen would know more. But Lori, do you think we've already contaminated Mars? Well, it's hard to say. And so there's a concept called planetary protection where you try not to do that. So it's, you know, make sure that you don't bring accidentally bring Earth life to other planets with your spacecraft.

00:37:45:08 - 00:37:49:06

Unknown

And so there's there's a lot of effort that goes into that. But, you know, who can say.

00:37:49:08 - 00:38:04:12

Unknown

So another question we got is kind of going back to the origin of life once life begins and how it is, how quickly does it start to spread out, how quickly, you know, what what does that look like? And or does it have to stay localized?

00:38:04:12 - 00:38:22:17

Unknown

Like what are your thoughts on that? Lori. Well, this is actually one of the big unknowns because it depends on what that life was like at first. Right? So if you started out, let's say with, I don't know, a cell that could not make its own organics, but it was eating the other organics around it. And it was it was fine as long as it was in its little prebiotic area.

00:38:22:18 - 00:38:50:02

Unknown

But then if it was to start moving away from the organics, it might not be able to survive. On the other hand, if you had a cell that was able to create its own organics, Fe, from carbon dioxide or something like that, maybe it could survive in other places. But then there's also, you know, the issue of conditions like what if, what if the cell, what if the first life was under water and it wasn't equipped to survive, say, high radiation, because the surface of the Earth in the early Earth was it had no ozone protection or anything.

00:38:50:02 - 00:39:06:22

Unknown

So there was a lot more radiation at the surface. So what if what if that life wasn't equipped to survive radiation yet? Or what if it started on land and it had all the salts it needed in the minerals and stuff? But if it goes into the open ocean, it won't be able to get any nutrients. So this question of, you know, how exactly did the origin of life begin?

00:39:06:22 - 00:39:19:06

Unknown

What kind of metabolism was it? What kind of energy did it use? That's why this is so important, because it kind of tells you what the first life probably was like, and where the spread and like the evolution of those first life forms probably would have gotten.

00:39:19:08 - 00:39:33:09

Unknown

there's this related concept of panspermia where maybe, you know, a chunk of maybe life actually began on Mars, maybe back when it had an ocean or something, and then it a chunk of it broke off through some kind of collision and hit the earth.

00:39:33:09 - 00:39:51:06

Unknown

And actually, you know, it didn't actually start here. It started elsewhere and was delivered. What are your thoughts on that? Either of you were both like, what do we know? What do you like that idea? How do you think about that? Well, origin of life. It just kind of it just adds another layer, you know, because life started somewhere.

00:39:51:06 - 00:40:05:01

Unknown

So it's either on the terrestrial planet that we live on, which makes a lot of sense because there's a lot of places on early Earth or that could have occurred or. Yeah. So if it's possible, life could, you know, move on a meteorite and come to another planet, then I guess it started on the planet from which the meteorite came.

00:40:05:03 - 00:40:24:18

Unknown

And so then you have to talk about origin of life on that planet's early history. And if it's Mars, then it's like, okay, are we talking about an ocean with land? And what kind of process? And so it's the same question. It just adds another layer. And, you know, it's it's kind of about like which which environments and which conditions can facilitate that origin of life.

00:40:24:18 - 00:40:36:19

Unknown

And a lot of the things that you might have had on Mars or Earth might be more similar to each other. So, you know, who can say, but it just it pushes the question back, but it's still the same question. Same. My answer to, okay,

00:40:36:21 - 00:40:43:02

Unknown

So we're getting a lot of really fun questions here. How concerned.

00:40:43:06 - 00:40:59:22

Unknown

Yeah. Go ahead Karen. Well, I'm looking at, two. I could take one, but you can ask your, you know, whatever you whatever strikes your fancy take. Well, Keith wants to know of subsurface brines exist on Mars. How does that potential habitability compare to Earth analogs, systems such as Antarctic subglacial lakes or deep crustal aquifers? I mean, this is something that I think about a lot.

00:41:00:00 - 00:41:19:09

Unknown

You know, what? And what do we have here? Because we're still we're still exploring the habitability of those places here on Earth. We're still kind of in the proving mode. I mean, we've kind of agreed that there's stuff there, but it's not very well known. So on Saturday, I'm going to go to South Africa and I'm going to go to a gold mine called my Cup Song in, the southern part of South Africa.

00:41:19:15 - 00:41:38:07

Unknown

And, I'm going to go down in an elevator three kilometers deep. So we drop at 60km an hour. It is terrifying. But it is very cool and very hot at the bottom. And I'm going to collect brines that themselves are a billion years old. So billion year old rocks are something that we we kind of know about.

00:41:38:07 - 00:42:05:15

Unknown

The billion year old actual water is something that is a little bit rare on Earth, but this stuff has been locked up for that long and we have found life in it before. We're just going to, you know, do some more work and, figure out what that life is like. But if there are things on earth that have been locked up and never seen the light of day, never gotten a rain drop, never got new, you know, some dead plants to eat for a billion years.

00:42:05:15 - 00:42:32:09

Unknown

That's a quarter, nearly a quarter of Earth's history. And things can live there. Then? Yeah, I think that there's there could definitely be things locked up in deep brines on Mars. If they're there. Wow. That's pretty cool. So speaking of life on Mars within. Otherwise, we got a great question from Lovell. What type of metabolism would you expect if we were to find life on other astronomical objects?

00:42:32:11 - 00:42:53:07

Unknown

Any thoughts there? Well, I think that that depends on the object. And so a lot of it is the environment that we're given, you know, and so there's all these, all these I guess factors that would go into what life do you expect to find? This is something we have to think about as astrobiologists. Because if you're going prepared to detect that life, you have to go prepared to kind of have some knowledge of what it might be.

00:42:53:09 - 00:43:09:22

Unknown

So if you're thinking it's a microbe, let's say that's going to be, I don't know, making methane, you could maybe look, go to try to detect the methane. And so you might want to make some advanced guesses on this. But the the things that would affect this would include what is in the environment as far as, fuel we call those electron donors.

00:43:10:00 - 00:43:29:04

Unknown

But what sorts of places can life get its energy from? Maybe hydrogen, maybe sulfide, things like that. And what is life going to produce? Like where all those and where all that energy go? It might make things like methane or maybe acetate or something else. And all of this is chemosynthesis, which is the of trophy that we were talking about.

00:43:29:10 - 00:43:45:07

Unknown

But also what if there is a world where there's just lots of organics? Anyway? Because, for example, some of the ocean moons, they're much smaller than Earth, and some of them are so small they never actually melted. So all those organics that came from the the asteroids and meteorites that made the moon, they're still there. So what if life just eats that?

00:43:45:09 - 00:44:02:12

Unknown

So, I mean, we kind of have to think about each planet and each environment and like what's present and what's what could life use? And there's a defined amount of energy that we know is present in each chemical combination that you can say, oh, this one has more energy and this one has less energy, but not everything is an option in every environment.

00:44:02:14 - 00:44:23:12

Unknown

We have a really cool question here. Okay. We know the moon, is a broken off piece of the Earth. Have we found any evidence there? If people looked on moon rocks or things like that, what do we know about whether or not you know there's evidence of past life on the moon? I mean, if that stuff was on the surface of the moon, it would be pretty well irradiated because there's not much atmosphere on the moon.

00:44:23:12 - 00:44:48:03

Unknown

Kind of like the same problem as Mars. So similarly to Mars, we would want to drill down deep to find it. Would you want to do that if I gave you $1 billion? I literally always want to drill into a planetary body. If you're ever wondering, I think. Okay. Very cool. Hey, let's go back to Europa. So just to sort of set the stage for, for folks to sort of understand what it.

00:44:48:05 - 00:45:11:10

Unknown

So it's this moon, it's icy on the surface, and there's pretty good evidence that there's an ocean underneath. It's not it's not ocean because it's getting light from the sun to heat it up. It's actually tidal forces from its orbit that are kind of heating it up and allowing that have that ocean there. It's really cool. That's, that's a certain set of conditions largely going back to you.

00:45:11:13 - 00:45:30:12

Unknown

What kind of life would you look for there, and how would it be different than say, you know, Mars or wherever? Well, I will punt the question to. And another moon, actually, because I don't study Europa, but I know a lot about Saturn's little moon Enceladus. So I thought about this a lot for Enceladus. It's a it's an ocean that is very alkaline.

00:45:30:12 - 00:45:51:14

Unknown

So it's around ten, 11. Like still more than bleach, I guess. And so it's it's there. But it is it is also contains a lot of carbonate, which is what carbon dioxide is going to do. And it's an alkaline solution and has lots of salts like ammonia and sodium chloride. And so if there's life there, then what sort of metabolism could it have?

00:45:51:17 - 00:46:08:09

Unknown

So I thought about you know, on Earth, if we want to use carbon from the environment, we can fix it in different ways. Some of those ways involve like May having a high ammonia concentration will help or some of those ways you might need light to do that. And so that's probably not as likely to have like a photosynthesis based biosphere on Enceladus.

00:46:08:11 - 00:46:33:08

Unknown

But in theory you might be able to do something like I don't know, there's different pathways where you could harness that carbon, assuming you had certain other things like the right enzymes and so forth. And so, yeah, I think carbon fixation, as we call it, which is where you take the geological carbon and make organics, there's certain types that might work, but there's other types that are very common on Earth, like photosynthesis, that probably aren't going to work because it's all underneath an ice shelf.

00:46:33:10 - 00:46:34:10

Unknown

Very cool.

00:46:34:12 - 00:46:49:14

Unknown

Karen, do you want to take David has this. Yeah. It's just, you know, broad question about inter terrestrials. Yeah. So we need to get better. Like I said, it's a young field. We just discovered them a few decades ago. It took me three years to write. Here's my book. Yeah. Took me three years to write this.

00:46:49:15 - 00:47:09:17

Unknown

We need to do a better job of the question is, is there more introductory material to understand this new biosphere? And we we're not. I think we need to work harder on making that for people. And I'm actively thinking about how to do it. We made a little cartoon called unearthed that at Scientific America. And you can find it if you Google or maybe I can drop the link in one.

00:47:09:17 - 00:47:28:23

Unknown

I'm not talking. So that's fun to like. Watch this little, explainer video. We explain a lot about the chemosynthesis in the Key of Life, the autotrophic as well, is a cartoon, and yeah, we need to work on that. Deep life is another book. It's by Tulsi on start. And it gets into sort of the the deep mines.

00:47:28:23 - 00:47:42:05

Unknown

It talks a lot about the mind that I'm going to go to next, next week. And that's another good layperson book. It's much more detailed than my book. My book is more surficial. And that one gets like deep into the issues. But yeah, I'm I don't know, we're working on it.

00:47:42:07 - 00:47:48:07

Unknown

We had some questions leading into this discussion that were more philosophical in nature.

00:47:48:07 - 00:48:11:16

Unknown

And I'm kind of interested in your your thinking about this. It was more about it was sort of like, well, what you're doing is very interesting, but what does it mean? How should it affect the way we think about ourselves philosophically? How does it change, the way human beings should think about their place in the universe or the role of science in society?

00:48:11:18 - 00:48:22:17

Unknown

Let me just ask you that kind of open ended question. What motivates you? Why is it important? And and how could affect the way we think of, see, understand ourselves in this, this vast universe of ours?

00:48:22:19 - 00:48:41:10

Unknown

All right. You want to go first? Yeah. Let's see. It's a good big question. It's an easy one. I thought I would just give you a very specific, easy question. Well, I mean, the reason I got into this specific research is really because I was thinking about these things, and I was a student, you know, I was, like, really interested in nature.

00:48:41:10 - 00:49:01:12

Unknown

And I always love nature. But, you know, I wanted to start knowing, like, what is my place in the earth and in the, in the universe and what is the what is the place of humans and also life in general. And, and so I thought it was really exciting when I was an undergrad in astronomy to learn about, say, how the sun formed and how the planets form and how the stars form the history of the universe and everything.

00:49:01:14 - 00:49:15:04

Unknown

And then at USC, I went to learn about the Earth and how the earth forms and all the life on it. And then and now getting to kind of study, you know, how that life began as it was the work I started after my PhD. And so now I'm kind of interested in, like, how does life actually start?

00:49:15:04 - 00:49:30:11

Unknown

Because we know how you get the planets and the stars. We know what life we'll start doing on a planet, that there's much to be discovered there too. But how do you actually start life? And then what does that mean for, as I call it, the study of life in the universe in general? Like what does it mean to have life in a universe?

00:49:30:11 - 00:49:38:08

Unknown

Where else would it be? And you know, why do we even have it here at all? So this is just something that drives me a lot. And this is why I chose my particular research program.

00:49:38:10 - 00:49:48:09

Unknown

and I think for, for me to answer that same question, you know, to, to understand that there's so much more diversity just here on Earth than we knew about before really puts me in my place.

00:49:48:09 - 00:50:08:09

Unknown

And it makes me feel it makes me feel less alone, I think, in the ways that people want extraterrestrials to make us feel less alone. We're we're less alone than we even thought we were here on our own planet. So it gives me hope of, you know, you can sort of, like, stare at things in a telescope and be like, if there was something alive there, I would see skyscrapers or something like that.

00:50:08:09 - 00:50:27:10

Unknown

And. No, you know. No, there's cryptic life. I mean, it doesn't mean that it's lifeless at all. So it gives me knowing about this stuff and spending all my time thinking about it really gives me a lot of hope. And I see a lot more possibilities and interesting questions and places to find life. In the universe, not just our solar system.

00:50:27:12 - 00:50:59:10

Unknown

How rare to to both of you in the scheme of things, you know, the evolutionary pathway that ultimately led to creatures like us that ask ourselves these questions and try to discover other kinds of life right. We're sort of weird in that respect. Are we kind of an evolutionary accident? Would you expect that given up enough time, things as complex and unusual as ourselves to be inevitable?

00:50:59:12 - 00:51:19:01

Unknown

What are your thoughts on that? Or do you even think that's the right question? I think it's inevitable. I think I think a lot of what drives the development of complexity of life on Earth is the fulfillment of the second law of thermodynamics. I know that sounds like reducing something beautiful to down to cold, hard scientific fact, but it is true that we have.

00:51:19:05 - 00:51:41:10

Unknown

The second law says that entropy must always increase in an open system, and that's often by way of heat and consciousness or, you know, higher order thinking or societies are just really, really good at creating entropy and changing. And entropy can be seen as like the quality of, of energy. It's not really energy itself. But I don't know.

00:51:41:10 - 00:52:03:03

Unknown

I just think that it's a natural outcome of what is demanded by the second law of thermodynamics to have systems that are really, really good at very varied and complex ways of pushing things out of equilibrium so that further entropy can be produced. If that's not too reducing all the beauty, I like that. I think that's a fundamental answer.

00:52:03:05 - 00:52:31:18

Unknown

I like that, yeah, I answered Laurie, any any perspective. Yeah, yeah. So I would agree. And I think I think about these things too, in terms of, you know, timelines and alternate timelines, like, you know, some things are an inevitable trend, but also the specific way that it manifests in an organism or in a biosphere might vary. And so there's these, you know, bottlenecks perhaps in evolution or in the origin of life, where, you know, some parts are kind of easy to perceive, but then other things, you really need something specific to happen in order to continue.

00:52:31:21 - 00:52:52:09

Unknown

And how likely are those particular things, like in the early, early days of life, you know, there would have been the need to start creating those disequilibrium that Karen mentioned, say, across a cell membrane to be able to generate those gradients that all life uses. How likely is that to happen? Because without that, it all falls apart? Or how likely is it to get to the eukaryote which happened, what, 2 billion years ago?

00:52:52:11 - 00:53:09:11

Unknown

And, you know, certain metabolisms we need to be able to use, let's say, oxygen as, an electron acceptor where you would put those energy. And so things like this, like, you know, how how likely is it to get all the pieces just right? And maybe there's other outcomes that do use those same pieces that don't look just like us.

00:53:09:16 - 00:53:15:07

Unknown

So I'm interested in, you know, what would the alternate timelines look like assuming these different sets of conditions?

00:53:15:09 - 00:53:31:00

Unknown

Maybe you go back to something, more personal from your own, you know, scientific trajectories. Was there any particular discovery that you made maybe early on or an experience that then said, oh, yeah, this is this is absolutely what I want to do?

00:53:31:02 - 00:53:53:14

Unknown

Feel free to either of you take that one. Probably. After I had seen the first terrestrials and didn't know what they were and so didn't know how exciting they were just yet, I kind of set them aside in my lab notebooks. I was working to find, an organism that we think does one particular metabolism, but I thought maybe it would reverse its metabolism and go that other direction.

00:53:53:14 - 00:54:18:16

Unknown

So I went to a layer of sediment where it should be doing the reverse metabolism. And if it if it was dead or if it wasn't doing it, then it shouldn't be like actually expressing its biomolecules. So I developed an assay to look for its biomolecule and I remember standing at the University of North Carolina at looking at the gel, and I was so anxious to look at my gel that, that's just how we visualize things, that I didn't wait to put the, like, hood over it.

00:54:18:18 - 00:54:37:09

Unknown

It's, ultraviolet light. So I had a face shield on, you know, the really anxious one where you can't. Like, I had to get up on it and look at it. And when I saw that little band show up, I got the Hallelujah chorus, like, from Handel's Messiah. Like playing out in my head. And it just. It carried me the rest.

00:54:37:09 - 00:54:55:13

Unknown

I can't believe I just discovered that. Like, it's just as if you're not a scientist and you have a way to become one. Like, just do it because it is the coolest feeling to know that you know something true about the natural world that literally nobody else on earth knows. Like that is just such an amazing feeling. And then, you know, you got to tell people about it.

00:54:55:13 - 00:54:56:20

Unknown

That's your job

00:54:56:22 - 00:55:11:05

Unknown

Or you got one of those. Yeah, I got a quick one. So I was studying hydrothermal chimneys and making them in lab. And we're making them like these little towers of mineral. They're very cool. And, you know, theoretically they should generate energy like a battery. And so there's reason to believe this should happen in lab.

00:55:11:05 - 00:55:25:02

Unknown

So I put a wire inside one and a wire on the outside. And I thought, can I measure this like with a voltmeter like you would for a battery. And you could, you could see the voltage. And I thought, oh, so if I got enough voltage, could I light a light bulb or something? And so we got this tiny LED light and I hooked it up to the wires.

00:55:25:04 - 00:55:38:20

Unknown

And, but it doesn't work because it doesn't have needs like certain chemical combinations and so on. So I said to my student, I was like, I have to go to meetings, but if you get this to work, just like text me and I'll just leave the meeting. And so a little while later, days later, she says, I got it.

00:55:38:20 - 00:55:51:23

Unknown

And I was like, I'm out. And I just like, left my meeting. And I came back to lab and the light bulb was on because she found the right kind of combination of chemicals that will generate energy in a hydrothermal chimney. And so now we said, hey, instead of a light bulb, you could probably drive a chemical reaction.

00:55:52:01 - 00:56:07:22

Unknown

And that's the sort of thing that we try to do for the origin of life. So that was a very exciting day, and I don't even remember what the meeting was. But I remember when my intern said we lit the light bulb with the chimney. Oh my gosh, let me see. This is so yeah, that stuff is not so spent the life over the years.

00:56:07:22 - 00:56:32:22

Unknown

So we have time for maybe a couple one more kind of quick thing. Yeah. This is more about the nature of your teams. You know, what you're doing is fairly interdisciplinary. And, you know, how do you think about this diversity of expertise and how that shapes what you do? It's more of this kind of broad question of like, you're you're working kind of naturally at the interface of lots of different fields because of the kind of questions you're asking.

00:56:33:00 - 00:56:50:14

Unknown

What's your perspective on that interdisciplinary and how does it affect, you know, your success? I think it's absolutely crucial for everything that I do. I don't think that there's any of the big discoveries that I've been a part of that wouldn't have been possible without merging really disparate types of scientists who don't normally talk to each other.

00:56:50:19 - 00:57:17:08

Unknown

And, I also think it's important to draw in people who are not of the social groups, who tend to be scientists. I think that that is not a virtue signaling thing like that is actually vital for the continuation of science in general, is bringing people with different perspect personal perspectives who grew up in different places and with different life experiences into scientific discovery, because that's the kind of stuff that creates big discoveries.

00:57:17:10 - 00:57:38:13

Unknown

Absolutely. Agree. And this is why I take students in my group who are from all different majors, like we really do need the geologists, the physicists, the electric chemists and also the collaborators. I mean, one of my most valued collaborators that I work with all the time studies wastewater treatment. And it turned out that the wastewater reactions that are going to purify water are a lot of the same ones that we're looking at for how nutrients would cycle in a in an ocean on early Earth or Mars.

00:57:38:19 - 00:57:47:10

Unknown

So you just never know who you'll meet and what perspective they might bring. And I mean, working with her is that galvanize my research. And so it's always great to meet people from different fields.

00:57:47:12 - 00:57:55:17

Unknown

Karen. There's a there's a final question that's related to sort of the practical payoff of the research that we're doing here. Talk to me about that.

00:57:55:19 - 00:58:14:16

Unknown

Yeah. The cool thing about basic research is that you're cracking open such big questions. You don't really know what the practical aspects are, but if you look at the the number of functions from biotechnology that came from life, from strange life that we've discovered by discovering all this other new life, we can mine that for all kinds of things.

00:58:14:16 - 00:58:27:04

Unknown

You know, we use enzymes in food production, in medicine, in, all kinds of bio industries. So, I think it's limitless, the practical. This is absolutely practical stuff. We just don't really know what it's going to be yet.

00:58:27:06 - 00:58:34:05

Unknown

And with that, we will stay tuned to find out about all of those practical things that will become a loan.

00:58:34:07 - 00:58:53:11

Unknown

So this has been, for me at least, an absolute pleasure. I've enjoyed geeking out with both of you and asking asking these questions. What important, interesting, fundamental stuff. Thanks to everybody, who joined us live today. I hope you enjoyed it as much as I did. So again, thanks to both of you.

00:58:53:13 - 00:58:57:00

Unknown

And so long. Bye bye bye. Thank you.

00:58:57:02 - 00:59:08:08

Unknown

We hope you enjoyed this episode of the Dornsife Dialogs podcast. Please leave us a rating and a review wherever you listen. Thank you for your support. Bite on.