Into the Impossible With Brian Keating - Is Earth Unique? Mario Livio and Jack Szostak on the Odds of Alien Life [Ep. 457]

Episode Date: September 10, 2024

Does life exist beyond Earth, or is our planet genuinely unique? Can we recreate the origins of life in a lab? And what role does Mars play in the quest for cosmic life? I had the extraordinary honor of discussing this with two outstanding scientists, Mario Livio and Jack Szostak. Mario and Jack just released their new book, Is Earth Exceptional?, which seeks to answer whether life is a freak accident or a chemical inevitability. Tune in and join us for this mesmerizing exploration! Mario Livio is an astrophysicist and author known for his work in cosmology and his popular science books. Livio has significantly contributed to our understanding of dark energy, black holes, and other cosmic phenomena.  Jack Szostak is a prominent biologist and Nobel Laureate known for his significant contributions to understanding life's fundamental processes. He was awarded the Nobel Prize in Physiology or Medicine in 2009, along with Elizabeth Blackburn and Carol Greider, for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase. Key Takeaways: 00:00:00 Intro 00:01:33 “Life existing only on Earth is arrogant.” 00:04:09 Miller–Urey experiment 00:08:35 Does extraordinary evidence exist? 00:10:12 Judging a book by its cover 00:14:11 The origin of life  00:22:18 Thoughts on Rare Earth by Ward and Brownlee 00:24:59 The role of magnetite in the origin of life  00:31:30 Life on Mars?  00:55:15 Drake equation  00:58:54 Outro  Additional resources: ➡️ Learn more about Mario Livio: 💻 Website: https://www.mariolivio.com/  ➡️ Learn more about Jack Szostak: 💻 Website: https://www.nobelprize.org/prizes/medicine/2009/szostak/facts/ ➡️ Follow me on your fav platforms: ✖️ Twitter: https://x.com/DrBrianKeating 🔔 YouTube: https://www.youtube.com/DrBrianKeating?sub_confirmation=1 📝 Join my mailing list: https://briankeating.com/list ✍️ Check out my blog: https://briankeating.com/cosmic-musings/ 🎙️ Follow my podcast: https://briankeating.com/podcast ✨ Member's only playlist: https://www.youtube.com/playlist?list=UUMOmXH_moPhfkqCk6S3b9RWuw Into the Impossible with Brian Keating is a podcast dedicated to all those who want to explore the universe within and beyond the known. Make sure to subscribe so you never miss an episode! Learn more about your ad choices. Visit megaphone.fm/adchoices

Is Earth exceptional? Or are we alone in the vast cosmos? Today on Into the Impossible, I have a conversation with two giants of modern science. Mario Livio, an astrophysicist who worked on the Hubble Space Telescope, and is the best-selling author of seven books, including The Golden Ration and Brilliant Blunders, and Jack Shostak, a professor of chemistry at the University of Chicago, leaving the center for the Origin of Life. In 2009, Jack shared the Nobel Prize for Physiology or Medicine.

Today, we discuss life's uniqueness or ubiquity, the potential for existence of life beyond Earth. We challenge the interpretations of the Miller-Uri experiment and discuss ways that Jack is attempting to make synthetic DNA and efforts to create life in the lab. We discussed the controversial RNA-world hypothesis, how life could have originated from RNA, not DNA, And we talk about the surprising role of a molecule called magnetite, which could be the key that unlocks the mysteries of life on Earth and in the cosmos. Join us for an exploration of the uniqueness of life on Earth and whether or not life on Earth is all there is in the cosmos. Let's dive in. Any sufficiently advanced technology is indistinguishable from magic. Open the pod bay doors, hell.

In the end of the book, you say something along the lines of Earth being exceptional is a question that you almost regard as arrogant. Why should we be the only life in the universe? And I want to pose to you, what are the odds if somebody, you know, took your neighbor's pet cat that you love and, you know, threatened to do something to it unless you told them what your exact thoughts are about the odds of their being life, not the, you know, not the possibility of life. life, which I agree. But he said, life existing only on earth is arrogant. Why did you say that? The reason we say it's arrogant is because of this thing, you know, that we have now called the Copernican principle, which means that since the time of Copernicus and ever since then,

we just seem to be less and less significant from a physical perspective in the this universe. I mean, we weren't special in the solar system. Our solar system is nothing special in our galaxy. There are maybe a couple of trillion galaxies in the observable universe, and so on. So this is why it sounds arrogant to think that we are the only, you know, living things in this vast universe. At the same time, I mean, I want to say that what you asked about, the pet cat and so on, I would feel very, very uncomfortable with that because even before this, but even more so after we wrote this book, I realized how, you know, we actually don't have any idea of what is the probability of life starting in a place, even if the conditions

are ideal, because it requires lots of very... many things of which we know very little. You know, even if there are, let's say, 10 to the 10 or 10 to the 15 places in our observable universe, which in principle could start life, I don't know that the probability of starting life in a place is bigger or smaller than 10 to the minus 15. And therefore, in spite of the fact that I hate the arrogance, I honestly cannot say with any kind of confidence that I'm sure that there is life in our universe. One of the remarkable things I found about what I assumed to be your contributions, although it would be pretty funny. You know, it would be pretty funny if you wrote the astrophysics parts and Mario, I'm sure you could both do it.

But it was remarkable to me to hear the very careful description of modern day incarnations in your laboratory that are basically recreating or redoing in a proper way, the Miller-Ury experiment. Now, Harold Uri was a professor here at UC San Diego, as you probably know, and Stanley Miller was here too for a while. Talk to me about what was— Harold Vellstone at the University of Chicago, where I am. That's right. Yeah. Well, yeah. Another UC.

And that's where they did the experiment. That's right, yes. Well, come on, you got to give us, we're a public university, you know. Give a little love to another UC, Jack. Actually, you guys have a lot of, there are a lot of San Diegoans in this book, and that's great. But Jack, I want to ask you, what was wrong, quote unquote, with the Miller-Urie experiment? And how is your lab updating it, improving it and doing more modern versions, incarnations of it? For the time, the experiment was fantastic, right? There was a breakthrough. It made it obvious for the first time that some of the basic buildings. blocks of life or might not have been that hard to come by. I think the major change since then has been that we've realized you want to have chemistry that it can make a small number of the right chemicals, the right building blocks. And when you sort of blast energy through kind of atmosphere that Stanley used, you get, you know, thousands, maybe millions of compounds and small amounts. of even the most interesting. So it's not a good recipe for starting life, but that's not to say

that it wasn't a great experiment for its time. And what are the modern incarnations of it in your lab or waste? First of all, what were the lacunae, the problems with it perhaps, the oxidizing versus reducing? My audience is the most brilliant in the known multiverse, as Mario will tell you, but they may be a little more familiar with astronomy and physics than chemistry and biophysics. So please tell us, what were some of the claim challenges to it originally and how are we rectifying them today? Well, so you mentioned the atmosphere, the reducing atmosphere was, you know, lots of hydrogen and methane and ammonia and stuff. And that went out of favor for a while. People thought that it was much more likely that you would have a neutral or mildly oxidizing atmosphere with mostly nitrogen and carbon dioxide.

But over the last decade, the original conception has had a comeback as the outcome of large impactors on the Earth, which would generate a transiently reducing atmosphere that might last, depending on the size of the impact or anywhere from thousands to a few million years. That atmospheric chemistry is not by itself the problem. The real problem is, you know, we don't want to make trace amounts of a few amino acids. We want to make large amounts of the nucleotides that you need to build the genetic material of life. And so the major advances there have come from looking at lots of very different kinds of chemistry. And I would say that it's been largely driven by John Sutherland and his colleagues. students and we worked closely with John and what we're trying to do is take those materials

and the chemistry around them and see how do we get from there to the first cells. There's a lot of steps in there as well. So that's the kind of modern effort to understand the origin of life. Let me just add one sentence to which Jack now alluded. but, you know, I want to make this clear. The idea is that what is needed is high concentrations of a few important compounds, as opposed to lots of things at very low concentrations. That does not lead to anything useful. Right.

As I understand it, also a large amount of a large number of molecules is also not particularly a great starting point. recipe, although I'm no chef. Mario, I want to ask about our fellow astrophysicist long since unfortunately passed away, but I've had his widow, Andruyan, and his daughter, Sasha Sagan, on the podcast. That's Carl Sagan, if you can't tell, all the way out there. He said the following, you guys quoted in the book, Extraordinary Claims require extraordinary evidence. I don't know about you guys, maybe Jack in the back. I see some, like, maybe there's Talmuds back there. I'm not sure what's back there, but you have a file cabinet where you keep your extraordinary evidence. I mean,

I've always disliked that quote. I think it's inaccurate as we scientists do our work. We take everything. Everything could be extraordinary in the right context. How do you react to that claim that I'm making that there is no such thing as extraordinary evidence? There's just evidence. That is correct.

At the same time, the evidence, you know, needs to be convincing. And, you know, in the same way. So when I say extraordinary, I mean in terms of convincing. In mathematical terms, you know, I would say if you find something at the one standard deviation level, then that's not very convincing. If you find it at the 10 standard deviation level, then it is much more convincing. So that's what stands behind the extraordinary evidence. It means very strong evidence, one that, you know, you cannot, could not have happened just, you know, accidentally or something. Jack, now I want to do what you're never supposed to do, which is to judge a book by

its cover. But what else do we have to go on? So, Jack, will you take us through the title and the subtitle and the artwork on the cover? And then Mario, can you explain how this dynamic duo came together? The origin story of you guys working together on this remarkable book, which is unlike any other book I've read. The title on the cover are both meant to convey the recent evidence of evidence over the last 20 years that there are lots and lots and lots of planets out there orbiting other stars, right? You know, there's a very broad distribution of planetary types and environments, but it looks more and more like Earth-like planets, planets that formed in a similar way, and therefore would have similar environments that are probably not that uncommon. I mean,

I don't know what the exact fraction is thought to be these days, but as Mario said, There's an awful lot of stars out there and most of them have planets. So it seems likely that a lot of them would have started off in a kind of Earth-like way and would therefore have the possibility of giving rise to life. What we would like to know and hope to know eventually is whether that's the case. So we, from our laboratory work, we're trying to see if the pathway from chemistry to life, it's easy, implying that life might be common out there in the rest of the universe. And of course, half of the astronomical community is looking for signs of life out there.

So we're all interested in this question of how common or rare life might be. And Mario, how did you guys come to pair together theoretical astrophysicist, observational astrophysicist and a Nobel Prize-winning chemist, biochemist together? How did you make that happen? Let me just first say that one of the chapters that we talked about, you know, was, was life on earth a free chemical accident or was it inevitable? That's one of the things we're trying to answer in this book. Now, how did we come together?

If I'm not mistaken, the first time we met was some, I don't know, 20 years ago or more, at a meeting at Harvard, which discussed life. Jack was there, I was there. There were a couple of other Nobel laureates there. DeGovus, I think, was there and a few other people. And we then, you know, sort of heard each other and so on. And then over the years, when I organized a meeting on Life and so on, then I invited Jack.

And also I once moderated the panel of people who discussed Life. and Jack was a member of the panel. So when I thought about starting to write this book, this idea came to me. And you know, you pointed out yourself that such a book did not exist. The idea came to me that because at the end of the day, the search for life is a multi-pronged attack. We attack by searching for life in the solar system,

searching for life around other stars, but also with experiments of how did life start on Earth. So it occurred to me that, you know, that would be the way to go. And also, as we explained in the book, these two efforts actually have a very strong symbiotic relation between them. So I called Jack and asked him, would he agree to write this book with me? And he wanted to think about this for a couple of days, but after a couple of days, he agreed, and that's how it came about. Two, three months ago. It's peak pollination season, and my business is scaling fast.

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I had on Thomas Chek for his wonderful new book, The Catalyst, which is all about the surprising discovery, shocking discoveries made in his lab and elsewhere, and conventant discoveries made in Jack's lab and your discoveries. But we also got into, by the way, we spent the whole episode waxing rhapsodically about why RNA is better than DNA and how it deserves to get more attention. And it shouldn't be this neglected step cousin of DNA. But we also talked about criticisms of the so-called RNA world hypothesis. And the three that come to my mind are really sort of, they seem fatal to me, Jack. So I'm hoping you'll disabuse me of this notion. One that Tom and I talked about was the instability of RNA, that it's actually less stable than DNA. It's got this hydroxyl group that breaks off or gets hydrolysisized.

I don't know. I failed chemistry, Jack. You can probably tell. But the other kind of problem lacuna with RNA is the polymerization issues, the strands are thermodynamically unstable or unfavorable. And then lastly, that ribosomes, as he loves ribosomes, obviously, but they're not as efficient as protein. enzymes, and so you get this recurring chicken or egg. Robosome. Sorry.

Can you tell me, Jack, where am I wrong? I mean, is there RNA hypothesis on a solid footing as it's made out to be in popular culture, at least, or scientific circles? Yeah. I don't think any of the things that you brought up are actually really problems. RNA is not unstable. I mean, there's certain conditions under which it degrades rapidly, but there are other conditions in which it lasts quite long time. The polymerization issue is, I think, has been

kind of a red herring for a long time. I mean, it takes energy to derive the assembly of RNA strands, but I don't see why that's a problem. I mean, we need to understand exactly the right way to do that in a way that makes sense for the early Earth. But in principle, there's not really an issue there. Yeah, so far, ribosyms in general seem to be less efficient than protein enzymes, but it's probably good to remember that the ribosome, the machine that makes all proteins, is a rhizine, right? The catalytic core of the ribosome is RNA. That's generally thought to be the smoking gun for an earlier stage of life,

where RNA was the molecule that catalyzed reactions. Now, that's not to say that, you know, the final word is in. And then there's some new hints that things might be a little bit more complicated than that. And there might be one possibility that's been raised a few times is early polymers might have been a mix of RNA and DNA that's been somehow separated at a later stage. But, you know, these are the things that are kind of at the frontier that we're all trying to sort out. But, you know, the basic idea that nucleic acids played a key role earlier in life is, I think, is pretty solid. Look, the point is that you are talking about how life started. The fact, yes, DNA is better than RNA in storing information, and protein enzymes are better than ribosimes in catalytic, you know, reactions.

But you had to start with something that was supposed to do both the role of the chicken and the egg. And RNA is the best thing that could do that. At least we're not aware of something else. It could be, as Jack just said, that there was a phase in which a mixture of RNA and DNA work together. But it also could be that DNA is just a later invention. And things started simple. of my graduate students has proposed an experiment to finally settle which came first, the chicken or the egg. Would you like to hear it? I think we're going to hear it no matter whether we want to

hear it. Yes. That's right. You go on Amazon, you order a chicken and you order an egg. Whichever comes first, that's the answer. But in all seriousness, there are so many different, I mean, I counted two or three ranging for a chicken or egg type problems. And either one of you can address this, you know, DNA RNA and proteins, protocells, you know, how do you get a protocell? membrane first, and then the question of metabolism and genetics. I mean, any one of those sounds pretty insurmountable. And yet, I watched a lovely chat by Jack recently at something called membrane or membrane or something. I forget the name of it, a molecules TV, where you said it's not so hard to start the, that was the title of it with a question mark. So maybe Jack, you can say,

I mean, all of these chicken or egg type issues, which one is perhaps the most serious? You know, the metabolism first or genetics protocells, you know, cell membranes, lipid layers, and then we already talked about DNA and RNA, so you don't have to talk about that. But what do you view as the most significant challenge or criticism of, you know, how do you kick off this magical process that we call life? Yeah, yeah. I mean, I don't think of any of these as chicken and egg type problems. We want to start with very simple molecules, things like cyanide and, you know, abundant sources of

energy and by going deeply into the chemistry of these molecules and, you know, how they're affected by light and heat and so on, gradually understand how to build up more complicated molecules, the right set of molecules. So the nucleotide building blocks of RNA, the lipid building blocks of membranes. And I have to say that's one of the least well understood parts of the whole story. It's a challenge for chemistry, right? It's not a paradox or some insurmantable puzzle. It's just an area of chemistry that's not that well understood yet. And then, you know, we want to understand how all these things come together. Membranes have been known for many decades to be self-assembling structures. And so our nucleic acids, well known to self-assemble into interesting

structures. We want to understand the order in which these things happened. And, And you mentioned metabolism. So the way I think about that puzzle is life started off with a lot of things being made sort of outside of cells, out in the environment, possibly under, you know, more harsh conditions. And somehow that gradually transformed into chemistry that goes on inside cells under very mild conditions. And that's one of the huge challenges that I think people will be addressing over the next decade or two. Mario. Let me add a sentence. Yeah, go for it. Go for it. One of the things that, you know,

Jack and his coworkers and others, you know, have shown in the idea they came up with is that the protocells, the very initial cells, unlike modern cells, they were actually driven more by fluctuations in the environment rather than by things happening by the cells their own doing. And that is a big difference between the early cells and modern cells. Modern cells, as Jack just said, you know, they do everything internally. In the initial cells, in the proto cells, I mean, it was the environment that was providing both the nutrients and the things and the fluctuations in it were causing the cells to grow and then divide and things like that and so on. So this is a big difference between the early life

and life today. The one book that I found your book reminiscent of, in fact, it has one word in common, which is this book, Rare Earth by Ward and Brownlee. Obviously, your book has many, many, This is 20 years old or so. Many, many more updated references, new findings, new discoveries. I mean, they didn't even talk about, you know, Kepler in this book at that time. So besides the, you know, recent discoveries that have been, you know, obviously unknown to these authors, where do you differ from the hypothesis put forth by Brownlee and Ward that, you know, complex life is extremely rare? And I have to say, the evidence, you know, is sort of on their side. At this point, we haven't made convincing contact. I want to talk about scares, hype, and so forth that you guys

mentioned in the book. But Mario, tell us where do you differ with the hypothesis put forth by Ward and Brownlee? First of all, you know, the rare earth things sounds as if there is no life anywhere else. And that actually was not what they meant. They were talking really about complex, intelligent life. That's right. They did not object to the idea that life can start in other places. You know, we don't differ with them on that question. It is quite possible that simple life is common and complex life is very rare. It's possible. The slight problem I had with this book is that it almost sounded when you read that book that they already had their conclusion to begin with, and then they gave all kinds of lines of evidence trying to justify their conclusion.

And I think that, you know, for the time when they wrote this, this was a very reasonable thing to do. And I pointed out that we still today don't know whether life is inevitable or a free. accident, you know, on Earth. So at the end, it may come out that, you know, that they were writing that. And we have no real problem with them. This is something that bothers me a lot, especially when I see it in the scientific community, where people believe in something, they have a conclusion, and they selectively look for evidence to support their conclusion. That's not science, right? In science, we can have an idea, a hypothesis, And we look for evidence to test the hypothesis to find out, hopefully whether we're right or wrong.

And a good scientist doesn't mind being uncertain about the outcome of things. One incredible revelation to me, at least in the book, was sort of these other types of compounds that could be either acting as solvents or as catalyst or as, you know, nucleation sites for life. and one of the more kind of important ones comes from magnetite. Jack, I assume you played a role in that discussion in the book. Can you talk a little bit about magnetite and why it could be kind of the missing link to really mix metaphors? How could magnetite potentially play a role in the origin of life on Earth? Yeah, this has been a really surprising development over the last, like, five or so years. This addresses the question of the handedness of the molecules of life, at least most of them, right?

Molecules come in right or left-handed shapes, which are otherwise identical. And so then the question is, you know, that's been around since Pasteur, is, you know, why did life start with the handedness, the chirality of molecules that we see today? And there have been a lot of different attempts to explain this. The role of magnetite is that it could potentially form magnetized surfaces. And in the presence of a magnetic field, you actually have a chiral environment. And it's been shown experimentally that there's a particular compound that is kind of at the heart of nucleotide synthesis. that where one form of it, one of the two right and left-handed forms, will selectively crystallize on magnetite.

And that form, right or left-handed, depends on the magnetic field, whether it's up or down. So it's a potential explanation for how molecules with the handedness that we see today actually could have been selectively purified on the, earlier. You know, there's a lot more work that has to be done on this, but I think it is actually one of the most interesting and creative approaches to this problem that we've ever seen. Let me just say something, yeah. So first of all, this particular compound that Jack is referring to is called for short RAO. It was found that on the surface of these magnetites, a particular

chyrality is selectively chosen. Now, I still want to emphasize that which chirality is chosen, that is arbitrary. I mean, the idea is why is a particular chirality chosen at all? For example, in the case of the magnetites on Earth, in the northern hemisphere and in the southern hemisphere, it's the opposite carality because it depends on the Earth's magnetic field. So which one was chosen, that in itself may be an accident, you know, depending of where life started. But the fact that there is a chirality at all as opposed to, you know, it'd be a complete mixture of things and so on. There is nothing, Jack will correct me if I'm wrong, but I believe that there is nothing in a particular chirality that is more favorable for life than another. So we expect that they would behave in exactly the same way.

But the one thing that is clear is that in order to get life started, you had to have one or the other. And if you have a mix, that creates a lot of problems. So much effort being devoted to understanding how to get one or the other and get away from the mixture. Hey there, I know if you're enjoying this conversation, you'll want to get my Monday Magic mailing list, which is something. I send out with a bit of goodness to start your week off right.

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Now back to the episode. And I wonder if there's a cosmic connection as I read it, my friend Roger Blanford and his colleague Naomi Globus, four or five years ago, now I had a paper entitled to the chiral puzzle of life where they talk about cosmic rays that have chiral behavior as well. And of course, it's impossible for me as a cosmologist not to think about neutrinos, which are only left-handed versus DNA, which is right-handed. Mario, couldn't there be some connection between the cosmic and the origin of chirality

on the effect of life on Earth and throughout the cosmos even? I'll tell you, over the years, things of that nature have been suggested. But with the years that passed, those explanations fell one after the other. The idea was to really identify something that is crucial in the stages of the original life where chirality really, you know, is chosen in a particular way. And this is what these new studies of R.A.O. on magnetites has suggested. And that is really the right place where you want, because that is the kind of intermediate chemical compound that is crucial for the later formation of nucleotides and so on.

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The Hilton sale is on now. Book on Hilton.com or the Hilton app and save up to 20% to get the stay you expected. When you want savings, not surprises. It matters where you stay. Hilton for this day. Other frequent character in this book is the planet Mars. Now, I have a piece of the moon here, and I actually have a piece of Mars. I keep it away from my kids.

This is a piece of the moon, and it was delivered, you know, the ancient way by the U.S. Postal Service. Now, you can buy these things. And I want to just point out a plug for my listeners that have a .edu email address, which is half my audience, are students, postdocs, professors, and Nobel Priests. prize winners. And that you can get your own chunk of real meteorite, which may have brought life to Earth. We're about to talk about panspermia. If you go to my mailing list, Brian Keating.com slash list and sign up. And if you have a dot edu address, you can win one. But the planet Mars has a big role in this book for a variety of reasons, historical, astronomical,

but also cultural. And I want to get both of your reactions to this. I had said, I was on Lex Friedman's podcast a couple of years ago, and he said, what was? what do you think will happen after we discover life on another planet or elsewhere in the universe? And I said, nothing would happen. The next day, everything will be the same. And he said, oh, you've got to be kidding me. It'd be the biggest discovery of all time. And I said, we already know how the public would react because in 1996, there was a meteorite found in the Allenland Hills of Antarctica where I've been twice, not to the Allenland, I've been to the South Pole twice. And it was claimed to have, you know, evidence of microbial life from the planet Mars.

It was obvious the meteorite came from Mars, but the claim was that. And it was so important that it was actually featured in the only book that Andrurion wrote with Carl Sagan, the movie Contact, features a scene with Bill Clinton on the White House lawn saying, this rock speaks to us across the ages. And it does, and only the way that that slick willy could. And by the time there, you know, at the time, it was, of course, you know, debated as good science is as Jack just brought up. How do you do good science? But it wasn't really disconfirmed. It really had, it's been disconfirmed more or less in the consensus opinion of most astronomers and bioastronomy.

But the average public doesn't know that it's been disconfirmed. And so I claim that they're living under this impression for 18, you know, for 28 years that life is, you know, exist on Mars at one point. So how do you guys react to that? That actually we make a big deal of it. We would find it very important. maybe the public wouldn't really care that much, you know, a week and a half later when the next news cycle and some Kardashian is discovered on another planet. I coined the phrase, which I wrote

in the book, which discovering life and in particular intelligent life in other places will be bigger than the Darwinian and Copernican evolutions combined. And I stand by that in many ways, But at the same time, I also quote the head of the Vatican Observatory who says, listen, if the church has survived Galileo and Darwin and so on, it will also survive the discovery of life elsewhere. So I think that that is true. Now, look, there is a huge difference, I think, still, between, you know, when we talked about life at the ALH, meteorite, this was supposed to be very primitive type of life. If we would actually find signs of a technological civilization elsewhere, I believe that the reaction will be much stronger.

But it may still not be overwhelming if you think that that technological civilizations is, you know, many thousands of light years away, you know, and so on. There is something very funny. I was, Last Sunday I was in the city in New York here. I live near New York. And in one of the movie theaters, I saw this old, very old movie poster, which was called Superman against the Martian invaders. So, yes, there were many years in which the public was convinced that there are, that there is intelligent species on Mars.

At this point, I think, you know, we would all be quite satisfied if they find some signs of very primitive past life on Mars. And to be honest, I would be quite amazed if nothing is found. Because, you know, Mars and Earth formed from the same type of material and so on and this. They're in the habitable zone together. Yeah, so four billion years ago, you know, why there shouldn't have started something on Mars? And if not, may signal that you need some very precise conditions for life to start. We know there's been a lot of exchanges in materials. You were saying you have a Mars rock, right?

Right. I mean, I think one of the reasons to look for life on Mars is to see if it, in fact, had a common origin with life on Earth. I mean, that would be amazingly cool. Yeah, I want to ask you both about this reaction. So imagine if Mario's friend in MIT up there, Sarah Seeger, my friend, past guest on the show, imagine she's using the James Webb Space Telescope, and she detects, there's an exoplanet around a G-type two sub-giant star, just like our sun. There's two planets in a binary system orbiting around this very, very sunlike star, both of them in the habitable zone.

very close to each other. And she calls one of them is called Hattari, and the other one's called SRAM. And she's detected not only life, but there's actual creatures on there, you know, with like chunks of silicon in their hand and they can do all sorts of wonderful things and produce narrow band signals. And there's even, you know, red pigment, you know, chlorophyll type thing. Anyway, she finds all this incredible structure on one of the planets, Hittray. And then she wants to convince NASA to let her spend another $100 million worth of observing time to observe the other planet, the co-planet that's called SRAM. But NASA really wants to know that this is going to work out. Okay? So they want to make sure this money is very expensive. Mario can tell us

how much it costs per hour. But let's say she needs $100 million. Let it be surprising to find out that there's zero life, not just no iPhones and Android's or whatever. But there's not even a single, you know, prokaryotic form of life. Would that surprise you? Because if it does, I claim that we should be thinking very clearly about how hard it is for life to spread once it exists in a habitable zone around a star. So either one of you guys can take that question. In a Bayesian sense, how much emphasis should we put on the non-observation of life on Mars, given that there's abundant and technological life on Earth? If we were 20 years in the future, you know, we'll be on Mars. And so people would find advanced technological life on both planets.

If you look back in time, then I don't know. It's a different story. We don't know. I guess your emphasis was on these two planets that were orbiting each other or something. No, they're in the habitable zone. It's a SRAM is Mars spelled backwards and Hittari is great. Yeah, but look, I mean, for example, I mean, you know, you are aware that there is this. star, you know, Trappist one, you know, which has seven planets, three of which are in the habitable zone. Well, you know, there were great hopes about these planets because they are in the habitable zone. And yet at this point, as far as we can tell, these planets don't have atmospheres at all because they actually probably lost all their atmospheres by effects both

of the central star and also of the fact that they orbit very close. So there are currents, electrical currents formed in the atmosphere, so they lose their atmospheres. So, you know, objects that were thought to be very promising turned out to be less promising than we thought. At the same time, planets that were not thought as promising, planets like K-218B, for example, which, okay, there is no real sign of anything like life, but for a moment there, there was a claim that they found DMS in the atmosphere, which on earth at least is only formed by life.

So, you know, we can have all kinds of surprises. That's all I'm trying to say. This is why we're looking, right? I mean, because surprises are possible, and we may not find life where we expect it, And on the other hand, maybe we will find life where we don't expect it. Okay. So, Jack, this podcast called Into the Impossible.

And it's based on Sir Arthur C. Clark's famous phrase. The only way to discover the limits of the possible is to go beyond them into the impossible. And I'd like to use that as a chance to give you a moment with your 20-year-old self and go back in time. And what advice would you give him to do as you've done to go into the impossible? I don't know that I would do anything different because I've had fun. on my whole life, you know, trying to, you know, understand things, you know, try crazy experiments, not really be too much bound by what other people thought. So I would tell him to just carry on and do what he's going to do. All right. Well, that's great news because, yeah, until the Mario and

I invent the time machine. Jack, thank you so much. It's been a pleasure. Okay, thank you, Brian. Our friend Jill Tarter, who's been on the show a couple times, She said that we shouldn't really make a big deal about not detecting life because we've only, you know, radio signals, technological signals, not just life, but extraterrestrial intelligence. We shouldn't make a big deal of it because we've only searched the equivalent of a bathtub out of the ocean. I've always said that's kind of an argument against the high probability of life. I mean, if I go down to the ocean, I scoop up a bathtub worth of water a couple of miles from here on campus, Pacific Ocean, I'll find abundant life. If I don't, there's something really, really bad and something really going wrong. But that too would be evidence of technology because it means that we would have killed all the life. In the book, you claim that we've surveyed about 1% of our galaxy, which is I claim all we care about, right? I mean, Adam Frank, past guest friend of yours acknowledged in the book, he talks about life in the history of the universe, which is completely irrelevant, as I brought up with him. I mean, all I care about is stuff within a couple of, you know, maybe 100 light years of Earth.

But there's about 10,000 M dwarfs within a couple hundred light years of Earth. And we've surveyed them, we've looked at them, that we know about habitable, you know, potentially habitable planets. We haven't seen it. So when do you start saying that actually it's closer to being rare than or are truly exceptional than that? First of all, let's again, distinguish between intelligent or very complex life and very simple life, you know, early stages of life. You talked mostly now here, I think you referred more to intelligent life and things like that. So let me say something separate on intelligent life and something separate on simple life. On intelligent life, you know, there is this Fermi paradox, right?

I mean, which says that, oh, how come we haven't seen them yet, basically. But the thing is that, you know, we have certain conceptions about what intelligent life should be. And this is why we're looking for things like radio signals and optical signals. But it is quite possible that within, let's say, a thousand years, you know, even here on Earth, the intelligent species will be machines. it will be some AI type life. This would be the dominant thing. And if this is true that this is what's going to happen, that this may be the dominant life form in the galaxy or in the universe.

Now, for those, we're not looking because we have no idea how to look for those. They could be so much more advanced than us that if they don't want, we will never find them. Certainly, they don't have to be bound to a planet. They could live in space. You know, they do completely other things. All they need is some energy source and so on, things of that nature. So that's on the intelligent life part of things. On the primitive life part of things, your example with the water in the ocean is not a good example,

because the water in the ocean gets mixed. and this is why, you know, you will not find a bathtub worth of ocean water which does not have any forms of life in it. While, you know, in the case of the planet, simple life does not necessarily get mixed. And it's very hard to find. It is extremely hard to find. So what I hope will happen is, I'm sure you know, the decadal survey said that the big mission for the astronomical community for the next decade, is going to be finding whether or not there is life on other planets. And the idea is to have a telescope, you know, sometimes called the Habitable World Telescope,

which will manage to identify some 25 or so Earth-like planets for which will be able to characterize completely the atmosphere of these planets. And by characterizing the atmosphere, meaning, you know, to find the composition of the, those atmospheres and find out whether they have anything that resembles what life has done for the atmosphere on Earth. Once we do that, then we will be able to do what you alluded to. We may be able for the first time to place some meaningful statistical constraints on how rare or not life is. I mean simple life, yes? Suppose we look at these 25 planets and we find nothing. And they are all very much like Earth and we find nothing. Then at least we'll be able to say that, you know, with a probability of a few percent,

even when the conditions are fantastic, life does not necessarily emerge. What do you make of the, you know, kind of relatively, you call it shocking claims made by NASA scientists that we may have killed, or NASA may have killed Martian life in the Viking experiments by adding water? given the fact that water is a universal solvent and you guys speak very highly of it, why would it, you know, be possible to kill it? I mean, unless it's, you know, drowning a worm, which one of my kids did yesterday, it doesn't seem very like it. Well, you know, I read that paper and, you know, in principle, I suppose that's possible. But look, if there is life on Mars, I believe we will find it. Because indeed, you know, within not too long, we will be able to be able to. But, look, if there is life on Mars, I believe we will be able to be able to be able to be able to be. to land on Mars. Within about a decade or so, there will be sample return of soil from Mars and things like that. The inside NASA experiment just found that maybe six miles down, there is liquid water, you know, all kinds of things. So we will be able to study Mars and really tell whether there is anything or not. What about Titan, Mario? Talk about hydrogen cyanide, which, why is

Why is it a crucial compound for life on Earth, first of all? And what do you make of it being discovered in an ice cloud on Titan? Hydrogen cyanide is very important because the nucleo basis, which, you know, do the nucleotides, they are nitrogen-containing, and hydrogen cyanide already has carbon and nitrogen in it. So it's a very good compound to start with. It's amazing, by the way, I don't know if you noticed, that all the components thought to be crucial for the start of life are either things that are today considered serious poisons like hydrogen cyanide, like formaldehyde, or things that have a horrible smell, like H2 sulfur, you know, and things like that. This is why hydrogen cyanide is important.

Now, Titan is a very interesting object, no doubt, because it provides in principle two opportunities for life. One is that it has a large under the surface ocean. And second is that on the surface it has all these lakes of liquid methane and so on and this. So in principle, you could even have two different types of life on Titan. The same time, I will say that I'm not holding my breath for finding life on Titan because liquid methane is really not great for doing this. And that the temperatures on Titan, it is extremely difficult to get any kind of chemistry going. in the ocean that's underneath the surface, in principle, we argue in the book that life did not

start at the bottom of oceans. The main reason being is that you cannot get the high concentrations that you need. But oceans could sustain life once it's there. So in principle, if a rock with life was ejected, let's say, from Mars and reached Titan, it's not a very likely event, but it can happen, then maybe that life can be sustained in an undersurface ocean. So Titan is definitely an interesting object, but like I said, I'm not holding my breath for finding life there. As an astrophysicist, what do you make of the joint probability required for us to have this conversation, which are three different events? First of all, the formation of the Earth's moon from this pre-earth object, Thea, due to this incredible collision with some massive object the size of Mars.

That had to occur probably, well, I won't say the order, but we're going to keep going. Then there had to be the late heavy bombardment, which you talk up a little bit about maybe that's not a great term for it, but certainly there had to be the delivery of minerals and and ices and water to the earth's surface. We don't know of another way that could get there. comets, bombarding the earth. And then finally, the Chicksilub, Jurassic Extinction Event, 66 million years ago occurring not far from me in the, oh, it's pretty far from me, in the Yucatan Peninsula. Those things are like Tetris, Mario, right? They had to occur in the right order. It's not enough to just get this piece to match with this piece. No, no, you have to get it in the right order

to win the game. So what are the odds of that? I mean, if Chicksilub came first, first of all, If chicktub didn't happen, mammals may not have begun to thrive and then create iPhones and Zoom. But even besides that, if the heavy bombardment occurred before the formation of the moon, all the Earth's oceans would have been vaporized. So hasn't that seem incredibly unlikely? And are those conditions to have water and have a moon and be bombarded, but not too much at just the right time, don't those also add in just incredible layers of, improbability to the question and make Earth more exception. You are right, but you will notice that all of these contingencies relate to very complex or intelligent life. They do not prevent, you know, perhaps the appearance of some form of

simple life on Earth. So this is why I do feel that it is definitely the case that, you know, it is possible that the universe, you know, has lots of simple life, but not so much complex or intelligent life. I think that is definitely a possibility. Talking about, you know, kind of the future technology and tools that our colleagues will use, what are you most excited about in terms of future telescopes that could perhaps shed light, pun intended, on this age-old question? Indeed, this habitable world's observatory, that is the next big thing that you know will do. The idea is really to be able to characterize the atmospheres of Earth-like planets. That, I think, is the most important thing.

So I mentioned that our attack on the question of life is four-pronged. One is experiments in the lab to understand the origin of life. The second is search for life in the solar system. The third is search for life in the atmospheres of planets around other stars. And the fourth is this shortcut of trying to find intelligent life by some means. So I think that we should continue with all of these four things. I mean, Jack, his colleagues, John Sutherland, and others will continue to do all these experiments. all these experiments with the birth of life, if you like, the transition from chemistry to biology.

Searching the solar systems will continue. As I said, we will probably land on Mars. There will be missions to some of the moons of Jupiter and of Saturn and so on. Then there will be this habitable world thing, which... Mind you, I mean, you know, we could get lucky. I mean, the James Webb Space Telescope could in principle characterize the atmosphere of if there is life somewhere, if life is ubiquitous, you know, in the universe, then it could. But more likely, you know, we'll have to wait for the bigger telescopes that will work across a wide range of wavelengths to do that. One of the ways that you can perhaps identify a complex civilization is by the fact that they all have. waste heat. And that expresses itself in the form of otherwise unexplained infrared radiation.

So, you know, we could perhaps search for those to see if we can find something like that. When I think of the Drake equation, I'm always kind of startled that people still take it seriously 60 years after he created it. Because as we know as scientists, as real scientist, not not just people claiming to play them on the internet, that the actual answer in an equation is almost meaningless unless you have an error bar and an uncertainty, and that uncertainty should be divided into systematic and statistical terms. We now know that Drake equation has all these great terms, and they're all narrowed down statistically to very, very high precision, except for the most important ones, which have to do with the actual terms of interest, right?

You mentioned Sarah Seeger, a friend and past guest, you know, talking about her updated version, which also basically just takes the terms we know about from astronomy, segregates them, and then has the terms we don't know about from lifetimes and technology nucleation. What do you make of that? That actually you can get any number you want from the Drake equation, from 100% likelihood to zero to 20 decimal places. What do you make of the drinking? Unfortunately, you can. I mean, the Drake equation, I think, what it does.

does best is it highlights our ignorance. That's what it does. Because we have made great progress on the astronomical terms, and we have very good estimates for them. But then the really important terms which deal with the biology part, we have no idea about them. And so, you know, it is, beyond that, it is very hard to say anything really. So, Mario, as we close, I have a tradition of asking, you know, deep and meaningful questions, as you know, from being on two or three times in the past. I hope you'll come back many times. And they're all in some way related to Sir Arthur C. Clark. I already asked Jack, his one about what has he gone into The Impossible? I asked you that a long time ago. But I'm going to ask you a different question. The great Arthur C. Clark said the following. He said,

when an older but distinguished scientist says something is possible, he or she is very much likely to be right. But when he or she says something is impossible, they're very much like to be wrong, likely to be wrong. I'm going to ask you, what have you been wrong about? You've had an incredible career. You've written just a runaway, phenomenal best-selling books about the deepest, most abstract concepts in the known universe, from math to physics to astronomy and now life. Tell me, Mario, what have you been wrong about? So one of the things that I learned from writing this book with Jack was that I previously, honestly thought that it is not possible that with so many exoplanets and so many galaxies, you know, trillions of galaxies in the observable universe, there absolutely has to be life there. And it is very arrogant on our part to say that there isn't and so on.

But now, after understanding more about the origin of life, I see really how we have no idea what is the probability for life to start. And certainly, what is the probability, even if it started to evolve to a more complex type thing. So at this point, I really am not so sure. I don't know. So I don't know if I was wrong. But I, well, I was certainly wrong in trying to think that absolutely there must be life out there and maybe intelligent life. I think that was naive on my part. Mario, Olivia, this has been a phenomenal conversation.

I'm so glad we can have it. Congratulations on this wonderful new book. I am going to get to work editing this conversation so that we may have it out on Publication Day. This has been a just a delightful time for us to converse. I hope you're doing well, and I hope the book does phenomenally well for you. Thank you very much. Thanks, Brian. Yamava Resort and Casino at San Manuel is California's number one entertainment destination for today's superstars. Catch the Jonas Brothers return to the Yamava Theater stage on April 30th,

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