Cosmic Queries – Alien Oceans

Is ET hiding in the alien oceans of our solar system? Neil deGrasse Tyson and Jordan Klepper answer Cosmic Queries with Kevin Peter Hand, PhD, astrobiologist at NASA/JPL, author of “Alien Oceans,” and deputy project scientist on the Europa Mission.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:14Neil deGrasse Tyson?

  This is StarTalk. I'm Neil deGrasse Tyson, your personal astrophysicist, and this is a Cosmic Queries edition on the search for life in the universe. Co-host Jordan Klepper. Jordan, I miss you, man. I had you as a co-host once, and like, we gotta do this more.

• 0:34Jordan Klepper?

  Neil, I'm glad to be here. Today, we're searching for life, and we're searching for connection, and we've connected. So step one, completed. I need it more than ever right now. So it's good to hear your voice. I need some consolation. Let's hope there's more things out there in the universe. Fingers crossed.

• 0:50Neil deGrasse Tyson?

  Let's hope so. Let's hope so. So while I carry some expertise in this, I carry nowhere near what is necessary to be the expert on this Cosmic Queries. And we've got Kevin Hand. Kevin, from the Jet Propulsion Laboratories, Pasadena, California. Welcome to StarTalk.

• 1:09Speaker 02

  Thanks, Neil. Good to see you again, and thanks for having me.

• 1:12Neil deGrasse Tyson?

  Yeah, yeah. And you've just published a book called Alien Oceans. That's audacious.

• 1:21Speaker 02

  Thanks. Yeah, it's an exciting topic. At least I'm passionate about it, and I'm excited to share it with everybody out there.

• 1:32Neil deGrasse Tyson?

  It's got a big fat subtitle, "The Search for Life in the Depths of Space."

• 1:36Speaker 02

  That's right.

• 1:37Neil deGrasse Tyson?

  Love it. Princeton Press. So we know it's gonna be sort of academically enlightening. And plus, I just noticed that your Twitter handle is @alienoceans.

• 1:50Speaker 02

  That's right.

• 1:52Neil deGrasse Tyson?

  What's up with that?

• 1:54Speaker 02

  It's funny the way you can coordinate these things. So yeah, I've been working on the book for a long time, and in the book, we dive into our own alien ocean here on Earth, and then we go into our own backyard in the solar system and look at oceans that exist in the outer solar system that could harbor life.

• 2:17Jordan Klepper?

  Doctor, do you know if Alien Oceans will be open on Memorial Day?

• 2:23Jordan Klepper?

  Is that a local government decision? Or do you have any insight?

• 2:27Speaker 02

  You can open the book.

• 2:31Jordan Klepper?

  I'll take what I can get.

• 2:33Neil deGrasse Tyson?

  So, alien oceans, why not look for aliens in places other than oceans?

• 2:37Speaker 02

  Well, we are, and we should, and I hope that we can pursue all of these different dimensions and places when it comes to exploration. But these moons of the outer solar system, these worlds like Europa and Cetus and Titan, these are worlds where liquid water could be today. And of course, if we've learned anything from our study of life on Earth, it's that where you find the liquid water, you generally find life. And so, these worlds are incredibly compelling places to go and potentially not just find life, but life that is alive today, life that we could study and understand its fundamental biochemistry.

• 3:21Neil deGrasse Tyson?

  So, you are using an Earth-biased approach to the search for life elsewhere?

• 3:29Speaker 02

  That...

• 3:30Neil deGrasse Tyson?

  It's a confessive here in...

• 3:34Jordan Klepper?

  Get him, Neil!

• 3:37Speaker 02

  As Carl Sagan used to say, you know, he's a carbon chauvinist and... And...

• 3:47Speaker 02

  This is a really important point because...

• 3:49Neil deGrasse Tyson?

  Jordan, he's speechless, you see, so he knows he's guilty.

• 3:51Jordan Klepper?

  I know. This is what it is. This is when you poke through the bias, you get at what's really underneath, and it's nothing, all right? It's like the atmosphere of Jupiter. It's nothing. I don't fact-check that.

• 4:03Speaker 02

  Jordan, what do you think of carbon chauvinism?

• 4:07Jordan Klepper?

  You know, I come from a long line of carbon chauvinists, so I have empathy towards it. My grandpa was a carbon chauvinist. My dad, when he has a few too many drinks, is a carbon chauvinist.

• 4:18Speaker 02

  Thanksgiving's just a mess.

• 4:20Jordan Klepper?

  It's really a mess.

• 4:23Jordan Klepper?

  Don't bring Haddad in there, it takes... Yikes. Explosive.

• 4:28Neil deGrasse Tyson?

  But wait, it's one thing to be made of carbon. Carbon is a pretty fertile molecule, I mean, an atom to make all kinds of molecules. But you're going beyond just whether life is made of carbon. You're also asserting that it requires liquid water. That seems to me yet another... So, it's not only carbon chauvinist, you are a liquid water chauvinist.

• 4:49Speaker 02

  That's right. And so now in the book, I do go into, there's a, there's a whole chapter on speculating about a periodic table for life. Could there be many different modalities, many different chemistries, et cetera. But there's a good reason to at least initially target our search for water and carbon based life. And the reason for that is because of course scientifically, we need to frame an hypothesis. And so based on life on earth and how life on earth works, I can, we can put forth the hypothesis that if you bring

• 5:30Speaker 02

  together liquid water, carbon, and a smattering of roughly 53 other elements from the periodic table, plus some energy, et cetera, to, uh, to maybe get-

• 5:42Neil deGrasse Tyson?

  Wait, wait, wait. 53, that's not a smattering, that's half the elements.

• 5:46Jordan Klepper?

  That's a good, that's a, that's a heck of a picnic of elements right there.

• 5:52Speaker 02

  Some of, some of them are more important than others.

• 5:54Jordan Klepper?

  Wow, wow. Look at this. Oh, some elements are, oh, first, first you're a carbon chauvinist, and oh, and now you're completely disregarding half the elements. Who is this guy, Neil?

• 6:06Speaker 02

  I don't know. It's, it's really carbon and nitrogen and, uh, you know, you got some phosphorus, maybe a little sulfur if, uh, if you like.

• 6:14Neil deGrasse Tyson?

  Oxygen, yeah, yeah, okay.

• 6:15Speaker 02

  Yeah, you know, those, the, the big five, six, uh, elements in there. So, but the key, the key back to the water and the carbon is that we can, we can formulate this hypothesis that, uh, if conditions are similar to what we find inhabitable environments here on earth, and potentially in environments that we think-

• 6:40Speaker 02

  Were conducive to the origin of life. If those kinds of environments exist elsewhere in our solar system, then perhaps those environments, those alien oceans, could have given rise to life. There could be a separate, independent origin of life, and those worlds could potentially be inhabited.

• 7:00Neil deGrasse Tyson?

  I got a philosophical question for you. If you are only looking for life that you expect, and you find it, won't you be missing all the life that you don't expect?

• 7:10Speaker 02

  Ah, well.

• 7:12Neil deGrasse Tyson?

  And wouldn't that life be way more interesting than life that you expect to find?

• 7:16Speaker 02

  Right. And so here's the key. With any, with any mission, with any spacecraft mission, or frankly, with any experiment that we do in a lab or here on Earth someplace, we have to design the experiment around an hypothesis, but also try to make sure that the experiment is well-formulated such that we can make discoveries that we did not expect to make.

• 7:44Neil deGrasse Tyson?

  A serendipity mode?

• 7:45Speaker 02

  A discovery mode, a serendipity mode, I think. Yeah, that's a, that's a nice way to put it.

• 7:51Jordan Klepper?

  Set yourself up to be surprised, so that your lack of creativity in the planning stages is actually a bonus in the discovery stages.

• 7:59Speaker 02

  That's right. That's a good way to spin it. Exactly.

• 8:03Neil deGrasse Tyson?

  So Jordan, you collected questions from the internet on this very subject. So what do you have? If you lead off with our Patreon, because we're beholden to them as supporters of the show, but then we'll spill out into others who have asked, who have chosen to not support the show. But we don't lead with them, that's all.

• 8:23Jordan Klepper?

  I'm gonna start right off with Patreon patron Sven Bjorn Bird. Sven Bjorn's question is, will we have probes in the near future that will be able to take photos or videos beneath these water worlds?

• 8:42Neil deGrasse Tyson?

  Ooh, nice.

• 8:44Speaker 02

  Well, it's a great question and one that is very near and dear to my heart.

• 8:50Neil deGrasse Tyson?

  Because you have to dig through the ice. The water is not surface water, right? It's like below, like a kilometer thick layer of ice. So you got your work cut out for you.

• 9:00Speaker 02

  That's right. And so, I believe it was Sven. It really depends on how you define near term.

• 9:11Neil deGrasse Tyson?

  In the next thousand years, sure.

• 9:17Speaker 02

  So, this business is not for the faint of heart. I've been studying Europa and working towards trying to get missions out to Europa for fifteen to twenty years now. And we are a bit closer. So NASA has committed to a flyby mission, a mission that will orbit Jupiter and fly by Europa some forty-five plus times. And that's called the Europa Clipper Mission. And I'm part of that mission, but I'm also working very hard to get a lander down to Europa's surface. And hopefully that mission would happen in the... Hopefully it would land in the 2030s timeframe. But that's highly uncertain.

• 10:02Speaker 02

  We have no commitment from NASA or the government, et cetera, to get that mission done, so...

• 10:07Neil deGrasse Tyson?

  I just have to bring Jordan in on something. Jordan, you should know that in science, one of the first rules is whatever experiment you're a part of, it has to finish before you die. Okay, that's just it.

• 10:20Jordan Klepper?

  I will say, what you're describing, I have a bunch of screenplays that I don't think will get finished in my lifetime. I have an entire idea about me as a sexy cowboy that for some reason I've had studio execs tell me, "This is not going to happen in your lifetime."

• 10:38Neil deGrasse Tyson?

  Not in this lifetime, right.

• 10:40Jordan Klepper?

  Yeah, it's not in this lifetime. But I get that. I'm leaving this for the next generation.

• 10:46Speaker 02

  Yeah, so Jordan sexy cowboy script and Europa melt probe.

• 10:54Neil deGrasse Tyson?

  Wait, so that 2030 mission does not yet go through the ice? That just lands and looks around, right?

• 10:59Speaker 02

  Well, and it scoops in. We've got all sorts of novel drills and ways to sample the upper tens of centimeters. And that would help set the stage for a follow-on mission that would drill or melt through the ice and then potentially get into the ocean.

• 11:14Neil deGrasse Tyson?

  After you're dead.

• 11:16Speaker 02

  Well, here's the thing, Neil.

• 11:18Neil deGrasse Tyson?

  So the answer to be in Svoorn is no. That's your answer?

• 11:23Speaker 02

  Depending on how you define near term.

• 11:29Speaker 02

  Keep in mind, it was 400 years ago, over 400 years ago, that Galileo discovered these moons. And so, as depressing as it can be to work on these missions that take so long, I do like to keep it in perspective in that for the first time in the history of humanity, we can actually get this exploration done. It's been 400 years since Galileo discovered these moons. I guess I sort of approach it like, you know, these spacecraft are our modern version of cathedrals. These are incredibly complex undertakings. They take generations.

• 12:11Speaker 02

  They take a long-term commitment, which obviously in some of this day and age and the political whims, long-term commitments are hard to come by. So it's frustrating, but at the same time, I feel fortunate that I get to be a part of even a little bit of this.

• 12:27Neil deGrasse Tyson?

  Jordan, he did it again, Jordan. He can't get it built on time, so now they're cathedrals.

• 12:37Jordan Klepper?

  Doctor, as an atheist myself, now you're making me not want to get into a spaceship. That was like my last dream. I already know I'm not going to get into heaven. Now I can't get on a spaceship? What are you doing?

• 12:50Speaker 02

  Well, here's the thing. Technologically, coming back to the main question, there is nothing, there are no magic wands that need to be invented to get us through the ice.

• 13:03Neil deGrasse Tyson?

  That's an important point, a very important point.

• 13:05Speaker 02

  And, you know, as you argue a lot, Neil, getting to the nearest star, if we were tasked with doing that within 100 years, we'd have to invent some new fangled warp drive and it's a magic wand. There is no magic wand needed to be invented in order to get through the ice of Europa and into the ocean. If you could magically transport the Alvin submersible, one of our primary human submersibles that we use for the exploration of our ocean, if you could magically transport that to Europa's ocean, it would do fine for at least the upper half of that ocean. Once it got to the lower, the deeper half, the pressures would be a bit extreme. But nevertheless, most of our submersibles would work fine.

• 13:49Neil deGrasse Tyson?

  Wait, wait, how deep are Europa's oceans?

• 13:53Speaker 02

  So Europa's ocean is about 100 kilometers or 60 miles in depth.

• 13:58Neil deGrasse Tyson?

  Oh my gosh. And on Earth, the deepest is like five miles down or?

• 14:03Speaker 02

  Seven miles, 11 kilometers. And just by a fun quirk of the solar system, Europa's gravity is about a seventh of the Earth's. And what that means is that even though the ocean is about 10 times as deep as the Earth's, the pressure at the depth of Europa's ocean, at the seafloor of Europa's ocean, is comparable to the pressure in the depth of the Mariana Trench, the deepest region of our own ocean. And so the submersibles that go down to the Mariana Trench would do well in Europa's ocean if you could get them through the ice.

• 14:43Neil deGrasse Tyson?

  You just have to fly it there and melt the ocean and melt the ice and then sink it. And doesn't Alvin have somebody in it?

• 14:51Speaker 02

  That's right.

• 14:52Neil deGrasse Tyson?

  And you have to send an astronaut to go.

• 14:54Speaker 02

  Well, so.

• 14:57Jordan Klepper?

  This is a complicated cathedral.

• 14:59Speaker 02

  Beautiful tapestries, though, Jordan.

• 15:03Jordan Klepper?

  It's what you're saying, it's like, it's gonna need, it's gonna, it's gonna need a miracle.

• 15:09Neil deGrasse Tyson?

  Hence the cathedral reference.

• 15:12Speaker 02

  To get the funding.

• 15:13Jordan Klepper?

  Now I understand.

• 15:14Neil deGrasse Tyson?

  All right, Jordan, give me another, give me another one. Another Patreon question.

• 15:17Jordan Klepper?

  All right. Yep, this is from Patreon patron Dave W. Given the high chance that life exists in the oceans of Enceladus, why isn't Saturn included in the habitable zone of our solar system? Is the idea of a habitable zone even helpful for the search for extraterrestrial life?

• 15:36Neil deGrasse Tyson?

  Love that question, Kevin. Go for it.

• 15:37Speaker 02

  Yeah, it's a great one, man. Two pieces I want to dive into there. First, on the habitable zone, the question is spot on. And I go into this in the book. These alien oceans of the outer solar system are redefining the habitable zone. In the early days of astronomy and planetary science, there was this conception of the habitable zone where, in order for a world to be habitable, you had to be at just the right distance from your parent star, in our case, the sun, such that liquid water could be maintained and sustained on the surface. If you were too close, like Venus, you were too hot. If you were too far away, like Mars, you were too cold. If you were at the Earth-Sun distance,

• 16:20Speaker 02

  you were in that kind of Goldilocks zone or the traditional habitable zone. But what these worlds like Europa and Enceladus are teaching us...

• 16:28Neil deGrasse Tyson?

  You know what they're teaching us? That we have to take a break. And when we come back, we will find out what the modern understanding of a habitable zone...

• 16:40Neil deGrasse Tyson?

  Jordan, help me.

• 16:42Jordan Klepper?

  It's hard. Habitable.

• 16:45Jordan Klepper?

  And cephalitis.

• 16:48Jordan Klepper?

  Mars. The Mars zone, just let's say...

• 16:51Neil deGrasse Tyson?

  Goldilocks zone, there you go. That the emerging Goldilocks zone has a different understanding. So Kevin, we'll get right back to you right after this break. This is Dark Talk.

• 17:16Neil deGrasse Tyson?

  We're back. StarTalk, Cosmic Queries, the search for alien life edition. And we have my co-host, Jordan Klepper. Jordan, love having you, man. Love it.

• 17:27Jordan Klepper?

  It's fun to be here. I'll take all the connection I can get. Thank you, Neil.

• 17:31Neil deGrasse Tyson?

  All right. And by the way, you tweet at Jordan Klepper, right? That's your Twitter handle.

• 17:37Jordan Klepper?

  Yep, yep. You can find me easy. Just know my name, which is maybe tough. But if you've done the hard part of figuring out who I am, you can find me on that.

• 17:45Neil deGrasse Tyson?

  And Kevin Hand at the Jet Propulsion Labs. You were director of the Deep Ocean Project. Did I say that right?

• 17:52Speaker 02

  The Ocean Worlds Lab.

• 17:53Neil deGrasse Tyson?

  Ocean Worlds Lab, and at the Jet Propulsion Labs in Pasadena, California. And we left off, we left the last segment where we understood the traditional, classic definition of a habitable zone, a Goldilocks zone, not too close, not too far, just right for liquid water. What do we do about that idea now?

• 18:15Speaker 02

  Right.

• 18:15Neil deGrasse Tyson?

  Now that we've got moons way outside that zone that are kept warm. What's going on?

• 18:21Speaker 02

  Right. So we've got this new Goldilocks in town where the energy for maintaining and sustaining liquid water comes not from your parent star, but rather from the tidal tug and pull that these moons experience as they orbit their giant primaries. Europa orbits Jupiter, and Jupiter is some 318 times as massive as the Earth. And Europa's about the size of our moon. And so as Europa is orbiting Jupiter, it's getting tugged and stretched, and that internal mechanical energy is converted into heat, and that heat helps maintain the liquid water ocean beneath Europa's icy shell.

• 19:03Neil deGrasse Tyson?

  It would otherwise be completely frozen.

• 19:06Speaker 02

  That's right. There would be some radiogenic decay, some heavier elements that might supply some heat that could maintain an ocean.

• 19:14Neil deGrasse Tyson?

  Radiogenic decay, radioactivity.

• 19:16Speaker 02

  That's right. Exactly.

• 19:17Neil deGrasse Tyson?

  Okay.

• 19:18Speaker 02

  And so the tides combined with the radioactivity provides some heat to maintain an ocean beneath the ice. But there's a, so in this new habitable zone, I don't want it to go unappreciated that... Another curious, beautiful fact of our universe is that ice floats. And if ice did not float, then even if you had the tidal energy for maintaining the liquid water in this kind of new habitable zone of tides as opposed to solar energy, if ice did not float, you would not have a nice thermal barrier over these oceans, protecting these oceans from space.

• 20:02Speaker 02

  And so, just like, you know, building an igloo or building a snow fort where you crawl inside and all of a sudden you're nice and warm, ice and snow is on Europa and Enceladus form a thermal blanket over the oceans that are being heated from within by the tides.

• 20:19Neil deGrasse Tyson?

  Is it fair to say that if you crawl into an igloo, you're nice and warm, as opposed to saying if you crawl into an igloo, you're not as cold as you just were?

• 20:28Speaker 02

  Well put, yes, fair enough.

• 20:32Neil deGrasse Tyson?

  I don't know, you know, but when I think igloo, inside or out, I'm not thinking cozy, I'm just saying.

• 20:38Jordan Klepper?

  I see a positive here. You're telling me a martini that's shaken with a nice little ice layer is going to taste similar on Europa than as it would here in, say, downtown Manhattan?

• 20:52Speaker 02

  I'll go with yes.

• 20:53Neil deGrasse Tyson?

  Yeah, I don't know if he actually said that, Jordan.

• 20:56Jordan Klepper?

  I think, play that back. It feels like it was mostly a cocktail understanding. Yeah, it was something about ice floating, the right amount of gin, a little bit of sweet fruit, a kiss of olive, something like that. Is that what I was listening to? Is that what I was thinking about?

• 21:12Speaker 02

  There's lots of salt on Europa, you can make a margarita if you want, you know, it's there.

• 21:16Neil deGrasse Tyson?

  So what we're saying is, we can still think of a habitable zone, but not as some restricted place.

• 21:25Neil deGrasse Tyson?

  In the circumference of a star, that a habitable zone is any place you can have liquid water, and that could be wherever there's a source of heat.

• 21:33Speaker 02

  That's right. And so these subsurface oceans, as I describe in the book, these Europa's could be ubiquitous. And so when we think about habitable real estate in our universe, these subsurface liquid water oceans could be the predominant place where life resides.

• 21:53Neil deGrasse Tyson?

  And especially since there's so many of those such places.

• 21:56Speaker 02

  Exactly.

• 21:57Neil deGrasse Tyson?

  In our own backyard.

• 21:57Speaker 02

  That's right.

• 21:58Neil deGrasse Tyson?

  I see.

• 21:58Speaker 02

  Yeah. Now, the questioner had a, the beginning part of that question was, since it's likely that life exists within Enceladus, I just want to pick that apart a little bit. We don't know whether or not life is likely. We can put forth that hypothesis that the conditions within Enceladus and Europa and some of these other worlds might be conducive to life's origins and habitability.

• 22:26Neil deGrasse Tyson?

  But Kevin, Kevin, that, that's the scientist way that gets written as a headline by the press saying scientists found life on Enceladus.

• 22:34Speaker 02

  That's.

• 22:35Neil deGrasse Tyson?

  You just said the conditions are such that it was possible, but could have the likelihood of life. And then life found on Enceladus.

• 22:45Jordan Klepper?

  But, but we got ourselves a paper. We're taking it. We're going to print. We're not even fact checking. All right. This guy said something about cathedral. I don't know. Stick that in the end.

• 22:55Neil deGrasse Tyson?

  Martinis, it's all there. It's all in the same article.

• 22:57Speaker 02

  But, but the, as much as I would love to find life beyond Earth, as beautiful as that discovery would be, the non-discovery of life, if we were to go to many of these worlds, Europa, Enceladus, Mars, and find not a whiff of life, that also is a potentially equally profound discovery in terms of the rarity of life and the kind of biological singularity that, that life on Earth might represent. So.

• 23:25Neil deGrasse Tyson?

  Jordan, Jordan, he did it again. He said, if our experiment fails, that's a great result.

• 23:31Jordan Klepper?

  That's great. It really is.

• 23:33Neil deGrasse Tyson?

  That's the third time he's.

• 23:39Jordan Klepper?

  I wish I had listened to your explanation on this podcast back when I was taking classes in high school, that I could use these explanations to my mother of like, you know, I could do well, I could study, I could pass the test, but if I fail, you know, there's still some, some life lessons that I'm learning from.

• 23:53Speaker 02

  Yeah, but that's it. When you're doing an experiment, as long as it's a well-designed experiment, the outcomes yield knowledge either way.

• 24:03Jordan Klepper?

  Tell that to the grant.

• 24:07Jordan Klepper?

  I'm not buying it.

• 24:08Speaker 02

  Very good. So Jordan, you gotta, give me another question. What do you got going there?

• 24:12Jordan Klepper?

  I do. You know what? This is coming from Facebook and he's coming, he's coming at us. He's questioning some assumptions here. This is Lee Daly from Facebook. He wonders, is the life in our own oceans not terrifying enough?

• 24:25Speaker 02

  Whoa.

• 24:26Jordan Klepper?

  Shot fired, Lee.

• 24:29Speaker 02

  Yeah, I don't know quite how to interpret that. I would say I've gotten to make nine dives to the bottom of our ocean and also I've been a part of a number of expeditions to send robots down to our ocean. And it's not, I wouldn't qualify it as terrifying. It's beautiful. It's astonishing. It's just jaw-droppingly bizarre. On one of my dives, we encountered this two-meter diameter space bagel-like creature. That was this, this undulating jellyfish. And seeing life within our ocean and studying life within our ocean

• 25:10Speaker 02

  helps inform not only how our home planet works and, and the understanding the biological diversity of planet Earth, but it also just guides us and inspires us when we think about these deep, dark, distant oceans beyond Earth. And, and in particular, life at the hydrothermal vents in our own ocean is, is really the kind of oasis in the deep ocean that we look to when we think about what might exist in the regions where photosynthesis cannot operate in these ice-covered oceans like Europa and Enceladus.

• 25:44Neil deGrasse Tyson?

  Wait, so hydrothermal vents, that's where the continents are separating and you got heat, there's a source of heat that's not the sun.

• 25:49Speaker 02

  That's right.

• 25:50Neil deGrasse Tyson?

  That's under the, under, under the, and deep, so deep that the sun can't reach. Sunlight doesn't reach it. So if you're gonna have life there, it's gotta figure something out.

• 25:58Speaker 02

  That's right.

• 25:59Neil deGrasse Tyson?

  That's, that's, that's not in your biology book.

• 26:02Speaker 02

  That's right. So traditionally, we learn that the food chain, animals eat animals and plants and so on and so forth. And eventually you get down to photosynthesis. And photosynthesis serves as the base of the food chain. Well, when you go into the depths of our ocean, of course, sunlight doesn't get there. And so photosynthesis can't form the base of the food chain. But what microbiologists found back in the late 1970s is that these hot springs, these, these hydrothermal vents at the bottom of our ocean, provide a tremendous menu of interesting compounds that microbes love to eat for lunch and dinner.

• 26:45Speaker 02

  And they, they then do chemosynthesis, using the chemistry to synthesize the compounds they need. And then other organisms eat those microbes and so on and so forth. So you get this, this food chain that is fed off the chemistry of the vents. And we think that kind of dynamic, that kind of ecosystem, might be an interesting example for what could happen within these ice-covered oceans of the outer solar system.

• 27:12Neil deGrasse Tyson?

  All right, that keeps you going. Very good. All right. So what do you have next, Jordan?

• 27:18Jordan Klepper?

  I got, I got one, I got Lori Muller from Twitter. Lori wonders, "Do we have the ability to identify non-carbon-based alien life? Or will our perspective prevent that? What's NASA's official criteria for identifying alien quote-unquote life?"

• 27:34Speaker 02

  Yeah, this is, this is a great question.

• 27:36Neil deGrasse Tyson?

  In fact, Kevin, let me, let me shape that a little differently to include our, part of our earlier discussion. If you are looking for carbon-based life, might you, does that preclude you from finding silicon-based life?

• 27:53Speaker 02

  The short answer is no, as long as you bring the right tools with you. And I'll give you a couple of different examples. And again, there's a whole chapter on this in the, in Alien Oceans. So...

• 28:09Neil deGrasse Tyson?

  But for those who just joined us, Alien Oceans is a book.

• 28:16Jordan Klepper?

  Context clues chapter would really help you figure that out. But, uh, thank you, Neil. Not gonna let something fly by.

• 28:23Neil deGrasse Tyson?

  I just wanna be, in full disclosure.

• 28:26Speaker 02

  Yes, there we go.

• 28:28Neil deGrasse Tyson?

  Okay.

• 28:29Jordan Klepper?

  We're not just so cavalierly talking about alien life. Just sort it out, like.

• 28:32Neil deGrasse Tyson?

  Yeah, go take a swim with the sharks and learn my books.

• 28:35Speaker 02

  Right. So, the, um, uh, this is a great question, Laurie, and it's one that has enlisted many PhDs, many grad students, many scientists. Uh, and it's one that we debate in the community constantly. Uh, and there's a thing called the ladder of life that you can Google and you'll find, uh, on NASA's official astrobiology webpage, this, this sort of tier of, um, of what we call biosignatures and kind of the, the efficacy and fidelity of various biosignatures leading up to claiming that you have actually detected life. And so, for example, if we sent a submersible down into Europa's ocean

• 29:17Speaker 02

  and a European octopus came up and waved at the camera, that would be one heck of a biosignature. We would have motility. We'd see this, this moving creature. Uh, we potentially.

• 29:30Neil deGrasse Tyson?

  And you wouldn't care what the hell it was made of.

• 29:32Speaker 02

  Right.

• 29:36Jordan Klepper?

  We would run with, that's front page news right there. We would run with that. We actually have pictures, great.

• 29:41Speaker 02

  And, uh, and to be clear, when we are talking about the search for life in our solar system, uh, whether it's Mars, Europa, and solid as Titan, we are largely talking about the search for even the tiniest of microbes. Uh, if such a discovery would revolutionize our understanding of biology, uh, and we would, uh, for the first time in, in human history, know that biology actually works beyond Earth. But so, uh.

• 30:06Neil deGrasse Tyson?

  Wait, just to be clear, just to be clear, Kevin, if the life you find on another planet is made of DNA.

• 30:12Speaker 02

  Yeah.

• 30:12Neil deGrasse Tyson?

  Then it doesn't revolutionize anything.

• 30:14Speaker 02

  Ah, yes, it could. Uh, so, um, uh, let's, let's come back to that though, because that folds into the, uh.

• 30:21Neil deGrasse Tyson?

  I don't mean to pick a fight or anything.

• 30:22Speaker 02

  No, no, it's a, it's a great one.

• 30:23Jordan Klepper?

  Neil, we need the, for the ratings.

• 30:27Jordan Klepper?

  Go with your instincts. This is good. We need this. All right. We gotta stand out.

• 30:33Neil deGrasse Tyson?

  Nerd fight.

• 30:36Speaker 02

  So to Laurie's question, there is this ladder of life and we've developed a biosignature framework. In other words, that not just one measurement is enough. You have to make multiple complementary and redundant measurements in order to have enough biosignatures that you can then claim that you've detected life. And you want to make sure that you have biosignatures that are as universal as possible.

• 31:02Neil deGrasse Tyson?

  By the way, Kevin, just to be clear, I want, we have to alert our audience. This is an astrophysicist using the word universal to apply to the universe. Most people on Earth who use the word universal mean all over Earth.

• 31:17Speaker 02

  That's right. Yes. We are talking about biosignatures, universal biosignatures being biosignatures that could apply throughout the universe.

• 31:25Neil deGrasse Tyson?

  Right. When they say, oh, this is a universal law, or Miss Universe, you know, this Miss Earth, really, you're talking about there.

• 31:32Jordan Klepper?

  That's right. Yeah. And to be honest, when I use universal truth, I'm just talking about what I believe.

• 31:39Speaker 02

  That's all we can ask for, Jordan.

• 31:45Neil deGrasse Tyson?

  Oh, sorry. Sorry to interrupt, Kevin.

• 31:46Speaker 02

  But think about

• 31:48Neil deGrasse Tyson?

  Universal

• 31:50Speaker 02

  Universal biosignatures. So think about if we were to use a DNA PCR machine or instrument in searching for life on Europa. PCR, polymerase chain reaction, that's obviously what we're using for looking for a lot of the COVID-19 virus. It's what is used by a lot of companies doing genetic analyses. And it's great. But that kind of instrumentation is contingent on that life using DNA. And so if we sent that kind of instrument to Europa, or Enceladus, or any of these other worlds, we could miss non-DNA based life.

• 32:29Speaker 02

  Meanwhile, so we're not gonna send

• 32:31Neil deGrasse Tyson?

  Life could be like rodeo riding the probe.

• 32:34Speaker 02

  Right.

• 32:35Neil deGrasse Tyson?

  And your device doesn't find DNA.

• 32:39Speaker 02

  And so, yeah, and so we say, oh, you know, game over. But an instrument like a mass spectrometer, I like to make the analogy to a mass spectrometer kind of being like a carpenter's hammer. You'll never go to a job site and find a carpenter without a hammer in their tool belt someplace. And mass spectrometers are a great way of sorting and identifying the various compounds, be they carbon compounds, be they silicon compounds, be they nitrogen compounds, you name it, a mass spectrometer gives you that inventory of compounds. And what's nice about that is that life, whether it's carbon based life, silicon based

• 33:21Speaker 02

  life, you know, all sorts of other permutations that we can't even imagine, life almost certainly needs to be specific in the compounds it uses. In other words, life will use a discrete set of subunit molecules to build the larger molecules of life. For life on Earth, it's amino acids, building proteins, nucleobases, building DNA. So a mass spectrometer would allow us to identify that kind of specificity in the building blocks.

• 33:53Neil deGrasse Tyson?

  Are they included in these missions?

• 33:55Speaker 02

  Yeah, so mass spectrometers, yeah, on the Europa Lander model payload, that's like prime instrument number one is bring something that can, without bias, give you the molecular inventory of what's there. Now, to DNA, to your question about DNA, which is, I love this one because it really is quite profound. If we go to Mars, and I love Mars, I'm doing some work on Mars 2020, it's a beautiful world.

• 34:26Jordan Klepper?

  Yeah, me too, just so, yeah, we're all on the same page.

• 34:30Jordan Klepper?

  No need to brag about it, equal footing, continue.

• 34:32Speaker 02

  Right, right. If we were to go to Mars and find evidence of DNA based life, and this would have to be in the subsurface of Mars, because our current search for life on Mars is in ancient rocks, and DNA doesn't last long in ancient rocks. But let's imagine that we got into the subsurface of Mars and found some water, and then we found DNA based life. I would, and many of my colleagues would probably conclude that that is evidence of a transfer of DNA life from Earth to Mars, or Mars to Earth, at some point billions of years ago, just because Mars and the Earth are near neighbors, and impact events, comets,

• 35:14Speaker 02

  asteroids, et cetera, hitting the Earth could have easily ejected material that then went to Mars, or vice versa. But with Europa, if we went out to Europa, or Enceladus, and we found DNA-based life, it's much harder for Earth to send microbial laden rocks out to Jupiter, and then once out there, it's much harder for those rocks to actually hit Europa instead of Jupiter. And even if they hit Europa, they're going to be coming in at something like 11 kilometers per second or faster, and then they annihilate themselves upon impact on the ice, and it's just a lot harder for an Earth rock to bring life to Europa or Enceladus than it is to

• 35:59Speaker 02

  Mars. So if we found DNA-based life on Europa, I would argue that that is evidence of biochemical convergence towards DNA as a fundamental molecule for life.

• 36:14Neil deGrasse Tyson?

  Analogous to if you go to a rocky moon somewhere else and you find quartz, or the geologic analog would be the same minerals are there that you find in the geology here on Earth.

• 36:27Speaker 02

  Exactly, and just like on Earth, we've had eyes, eyes have evolved independently some 50 times, maybe DNA is just kind of the convergent biochemical molecule that happens, or not.

• 36:39Neil deGrasse Tyson?

  And we're just too stupid to figure out how easy it is for nature to look up with that.

• 36:44Speaker 02

  Exactly. But this is why the outer solar system is so compelling, because there's liquid water there, and so these are places where large biomolecules, understanding the chemistry of the life, could be done. We could actually examine whether or not DNA is the only game in town, or there's some other way to get the business of life done.

• 37:06Neil deGrasse Tyson?

  So we got to take a quick break before we come back to our third and final segment. This is Cosmic Queries, this is StarTalk, this is Neil deGrasse Tyson. Stay tuned.

• 37:26Speaker 03

  Hey, we'd like to give a Patreon shout out to the following Patreon patrons, Matthew Poundset and Tom Bach. Thank you, guys, for your support. We could not do this show without you. And if any of you out there are wanting your own Patreon shout out, please go to patreon.com/stargtorkradio and support us.

• 37:51Neil deGrasse Tyson?

  We're back. StarTalk Cosmic Queries, Search for Life in the Universe. We've got Kevin Hand on hand, who just published a book, and the title is-

• 38:00Speaker 02

  Alien Oceans.

• 38:01Neil deGrasse Tyson?

  Alien Oceans. That's just the coolest title of a book ever, and there should be a movie-

• 38:07Speaker 02

  Thanks.

• 38:08Neil deGrasse Tyson?

  With that.

• 38:09Speaker 02

  Thank you.

• 38:13Jordan Klepper?

  If you get your movie made before my cowboy romantic movie gets made-

• 38:17Speaker 02

  John-

• 38:18Jordan Klepper?

  I would be so mad.

• 38:19Speaker 02

  I need some strong characters in the movie, so we gotta combine forces.

• 38:24Jordan Klepper?

  Sexy cowboy. I'll send you the script, okay?

• 38:27Speaker 02

  Do you mind dying a death by squid on Europa?

• 38:31Jordan Klepper?

  I'll take any of it.

• 38:33Neil deGrasse Tyson?

  And Kevin, where did this squid concept come from? Because in the movie Europa-

• 38:37Speaker 02

  Europa Report?

• 38:38Neil deGrasse Tyson?

  Of the Europa Report, yeah, they're like, I think they find a squid there. Like, what's up with that?

• 38:42Speaker 02

  That's right. Yeah, so I consulted on that movie.

• 38:46Neil deGrasse Tyson?

  Oh, you-

• 38:50Speaker 02

  I know a little bit about how that came about.

• 38:53Neil deGrasse Tyson?

  That's how you get- and did you also consult on the movie Arrival? We got more squids-

• 38:57Speaker 02

  No, but I love that movie. It was fantastically well done. I love the concept of that kind of communication.

• 39:05Neil deGrasse Tyson?

  You know, I worried, you know, there is the squid thing, the septapod-

• 39:10Speaker 02

  Yeah.

• 39:10Neil deGrasse Tyson?

  Drawing these circular patterns on this glass. And no one at any time asked, are we seeing these backwards?

• 39:23Speaker 02

  They got it wrong the whole time.

• 39:25Neil deGrasse Tyson?

  Well, just think about that, right? Is the squid drawing for our benefit or for their own benefit?

• 39:31Speaker 02

  Right. Yep. It'd be fun to redo that movie from their perspective.

• 39:37Jordan Klepper?

  I think the squid was of such high intelligence, they knew, oh, humans are always gonna think it's for greater benefit, so we might... That's what higher intelligence is, it's knowing that somebody else doesn't care enough about you to understand your own perspective.

• 39:49Neil deGrasse Tyson?

  That's exactly it. Or that their ego prevents them from having any clue about any other way to see the world. Yeah. Jordan, give it up, we've had for like, just one or two more questions here.

• 40:01Jordan Klepper?

  Great, this is from Facebook and Brent Whitlock. "While searching for life on different planets, do we risk contaminating aquatic environments with Earth biology by taking the plunge?"

• 40:14Neil deGrasse Tyson?

  Yeah, Kevin, you're talking about putting landers on Europa and looking for life? Did somebody sneeze on that lander before it left JPL? Like, what assurances do you have for us, that you're not gonna discover life that you brought there?

• 40:25Speaker 02

  Yeah, it's a great question, and one that is very important, and that JPL and NASA take incredibly seriously. And the short version is that spacecraft that are going to Mars to look for signs of life, or going to Europa and solid as Titan, etc., they are baked out and cooked to kill off any microbes, getting rid of any contaminants, they're cleaned extensively...

• 40:55Neil deGrasse Tyson?

  Sterilized.

• 40:56Speaker 02

  And essentially sterilized. And even on top of that, in the Europa lander mission concept, so the lander gets delivered to Jupiter in a bio-barrier, sort of a little envelope that makes sure it's perfectly clean. And then, the lander goes down to the surface, and even after the end of the mission, we still wanted to make doubly sure that it was not gonna contaminate the ocean, and so we have a little Mission Impossible button on the lander, where there's a little thermite system that our colleagues at Sandia National Laboratories have designed, where the last

• 41:36Speaker 02

  command that the lander would implement is a self-destruct button, and the thermite would sterilize the spacecraft even further by raising it to a temperature with a thermite flames.

• 41:50Neil deGrasse Tyson?

  Dun dun dun.

• 41:51Speaker 02

  Exactly. You got it.

• 41:56Neil deGrasse Tyson?

  Tom Cruise's next destination in the next movie.

• 41:58Jordan Klepper?

  Yeah, get ready. He's suiting up and training.

• 42:03Speaker 02

  Get him there to search for signs of life. That'd be great.

• 42:07Neil deGrasse Tyson?

  All right, Jordan, give me, see if we squeeze in a couple more. Go.

• 42:11Jordan Klepper?

  All right, got one right here from Phil Reeves in Facebook. What can finding life on other planets or moons in our solar system? Teach us about how life developed here on Earth.

• 42:21Speaker 02

  Yeah, it's a great one, and it comes back to the origin of life itself. And so, um, right now, there's quite a bit of debate about how life on Earth arose.

• 42:33Neil deGrasse Tyson?

  Jordan, that's science speak for quite a bit of ignorance.

• 42:39Neil deGrasse Tyson?

  Translation.

• 42:40Jordan Klepper?

  I'm consistently assuming ignorance, so I...

• 42:43Speaker 02

  But to be clear, it's well-informed, fact-based ignorance. Ignorance that's embraced.

• 42:51Jordan Klepper?

  Oh, I made a career on that, let me tell you.

• 42:54Neil deGrasse Tyson?

  So how informed is your ignorance?

• 42:59Jordan Klepper?

  Smartest ignorance there is. I know everything I don't know.

• 43:02Speaker 02

  So if we think about the history of our understanding of the origin of life on Earth, one of the great experiments was the Miller-Urey experiment, where a spark discharged with some methane and ammonia and water created amino acids. And...

• 43:20Neil deGrasse Tyson?

  All by itself, with no help.

• 43:21Speaker 02

  That's right. And so, the, um, ever since then, there have been a number of experiments, and they're kind of, broadly speaking, two camps. One is that the origin of life on Earth occurred in some warm tide pool on the shores of an ancient ocean, bathed in the ultraviolet light of the sun, and then desiccated as that little tide pool dried out. And through various cycling, you then get to life itself. And there's another camp that argues for a hydrothermal vent origin of life. And it turns out that a lot of the chemistry of hydrothermal vents might be conducive to some of the proto-metabolisms that we think would drive earliest life on Earth.

• 44:06Speaker 02

  And so those two camps, and there are others, but those are kind of two main camps.

• 44:11Neil deGrasse Tyson?

  Wait, wait. The biggest camp is God did it. That's the biggest camp out there. That's like Camp God. You're so outnumbered by Camp God.

• 44:21Jordan Klepper?

  It's the easiest to understand.

• 44:22Speaker 02

  Yes.

• 44:26Neil deGrasse Tyson?

  No complicated words, no...

• 44:29Speaker 02

  But let me put it in terms of fact-based ignorance.

• 44:33Neil deGrasse Tyson?

  Okay.

• 44:33Speaker 02

  So at least from that standpoint, there are those two camps of tide pools and hydrothermal vents. And so if we go to Europa, or Enceladus, or Titan, or any of these worlds, and do not find life, then that helps inform our understanding of how, of the modality for the origin of life on Earth. On Europa or Enceladus, there are no continents. There's no sun bathing in ancient seashore.

• 45:02Neil deGrasse Tyson?

  No tide pools.

• 45:03Speaker 02

  No tide pools. There's only hydrothermal vents. And so if we don't find life on those worlds, then perhaps hydrothermal vents are not a good place for the origin of life, and we can perhaps conclude that life on Earth arose in tide pools. Conversely, if we do find life there, then that makes the hydrothermal vent origin for life on Earth viable. It doesn't exclude the tide pool theory for life on Earth. I happen to think that the origin of life might be relatively easy and could occur many ways, in many different places, at many different times. But we have the chance to do this experiment, and the exploration of these alien oceans

• 45:47Speaker 02

  will help inform our understanding of this issue tremendously.

• 45:52Neil deGrasse Tyson?

  Well, I think we just ate up all the time we have. We just have time enough just for one deep sentence of reflection from each of you. Jordan, what is your deep reflective philosophical perspective?

• 46:10Jordan Klepper?

  You know, in the times that we live in currently, the times of uncertainty, time in and of itself has felt elongated and slowed down. But hearing about what it would take to get to Europa, and that we would have to build cathedrals, not only in our own lifetime, but another lifetime, I feel like this conversation warped time for me, and therefore made my existence right now, and my complaints about having to be inside for a week or two, feel small in comparison. So, thank you for a little bit of hope, and also for warping the space time.

• 46:48Neil deGrasse Tyson?

  So Kevin, he was feeling a little bit of the cosmic perspective there.

• 46:51Speaker 02

  There we go. We definitely have to consider the long arrow of time when we engage in these things.

• 46:59Neil deGrasse Tyson?

  So, other than buy your book, what one sentence wisdom can you share with us?

• 47:04Speaker 02

  I would simply say that we know of the four major sciences, physics, chemistry, geology, and biology, of those four major sciences, the past several hundred years have led us to an understanding that physics works beyond Earth, that chemistry works beyond Earth, that the principles of geology work beyond Earth. But when it comes to that last, that fourth fundamental science, biology, we have yet to make that leap. We don't yet know whether or not biology works beyond Earth. We don't yet know whether the phenomenon

• 47:48Speaker 02

  that is us, the phenomenon of life, works beyond Earth. And part of what excites me about the time in which we live, even though it's going to take a while, is that for the first time in the history of humanity, we can answer this profound, age-old question of whether or not we are alone. We can get out there in our solar system and explore these alien oceans that are in our own backyard and figure out whether or not life exists beyond Earth.

• 48:17Neil deGrasse Tyson?

  Well, what I wonder is, the expression curiosity killed the cat, in the case of scientists, there's life on Earth that wants to kill us, coronavirus included, and you want to find life elsewhere. So, the confidence that you have that that'd be a good thing, I don't know that that's shared by everyone on Earth when enough of life on Earth would just as soon have us dead. So, I'm just putting that out there.

• 48:48Speaker 02

  Send the robots and leave the robots on.

• 48:51Neil deGrasse Tyson?

  Let the robot do it. I'll sit back and eat popcorn while the robot is looking for life. Exactly. Kevin, great to have you on StarTalk Cosmic Queries. Jordan, I love you, man. We gotta do this more often.

• 49:02Jordan Klepper?

  Neil, I'm here.

• 49:04Neil deGrasse Tyson?

  Okay, excellent. Thank you both so much. Excellent. This has been Cosmic Queries StarTalk. I'm Neil deGrasse Tyson, as always, bidding you to keep looking up.