Latest / Daniel and Kelly’s Extraordinary Universe / Could we seed exoplanets with life?

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Could we seed exoplanets with life? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Kelly, I have an unusual aliens question for you.
• 0:11
  Speaker 2: It is never good for me when a question starts
• 0:14
  Speaker 2: like that. It's I have an unusual aliens question for you?
• 0:17
  Speaker 2: Or what is in my poop? As a parasitologist, I
• 0:21
  Speaker 2: get a lot of that, So go on, I can't wait.
• 0:24
  Speaker 2: Where are you going with this?
• 0:25
  Speaker 1: All right? So, as a parasitologist, do you ever see
• 0:28
  Speaker 1: a critter infected with something new? And wonder?
• 0:31
  Speaker 2: Hmm?
• 0:32
  Speaker 1: Is this an alien parasite?
• 0:34
  Speaker 3: No?
• 0:34
  Speaker 2: Never, There's so many weird things on Earth. I don't
• 0:38
  Speaker 2: feel like we need to go to space to explain them.
• 0:40
  Speaker 2: And the other day I saw someone trying to make
• 0:42
  Speaker 2: the argument, like in an actual like sciencey pop magazine,
• 0:46
  Speaker 2: that octopus like octopodes, Oh gosh, let's not get into
• 0:50
  Speaker 2: how you pluralize that might be aliens. And I'm like,
• 0:53
  Speaker 2: oh my gosh, dude, their genome fits nicely in the
• 0:56
  Speaker 2: tree of life. This isn't complicated. So the answer is no.
• 1:00
  Speaker 1: All right, But then my question is how exactly can
• 1:02
  Speaker 1: you tell? I mean, do you think like if alien
• 1:04
  Speaker 1: parasites did come to Earth, could they do their parasiting
• 1:08
  Speaker 1: on us? Would they find us tasty or be like
• 1:10
  Speaker 1: incompatible with us.
• 1:11
  Speaker 2: So that's an interesting question. You know, it might be
• 1:13
  Speaker 2: that they wouldn't be able to eat us, or that
• 1:18
  Speaker 2: they wouldn't be able to like, you know, bind to
• 1:20
  Speaker 2: whatever receptors inside of us they needed to. But you know,
• 1:23
  Speaker 2: for as far as how far or what do you
• 1:26
  Speaker 2: need to do to tell? You know, you could like
• 1:27
  Speaker 2: take a DNA sample and you know, see if they
• 1:29
  Speaker 2: fit on the tree of life or not. But yeah,
• 1:31
  Speaker 2: I don't know hard to know, so I guess I'd
• 1:34
  Speaker 2: say it's impossible to know. But I'm guessing that we
• 1:37
  Speaker 2: do look different from the kind of things that aliens
• 1:40
  Speaker 2: are used to sucking on out in space.
• 1:42
  Speaker 1: I'm going to take it as a compliment that aliens
• 1:44
  Speaker 1: don't want to suck on any parts of me.
• 1:46
  Speaker 2: You know, That's exactly how I meant it.
• 1:48
  Speaker 1: Did Hi, I'm Daniel, I'm a particle physicist, and I'm
• 2:06
  Speaker 1: doing my best to be not attractive to alien parasites.
• 2:10
  Speaker 2: I'm Kelly Widersmith, and you probably don't have any alien parasites.
• 2:14
  Speaker 2: But if you do, send them to me, because I'd
• 2:16
  Speaker 2: love to see them.
• 2:18
  Speaker 1: How are we going to find out? Kelly? Are you
• 2:20
  Speaker 1: planning to chop me up to see.
• 2:21
  Speaker 2: Sure, yeah, better you than my kids.
• 2:26
  Speaker 1: You didn't take very long to think about that. You
• 2:28
  Speaker 1: went right into Yes, I'm gonna chop up my co host.
• 2:31
  Speaker 2: Some questions are easy to answer.
• 2:35
  Speaker 1: And welcome to the podcast Daniel and or He Explain
• 2:39
  Speaker 1: the Universe, a production of iHeartMedia where we tackle all questions,
• 2:43
  Speaker 1: those that are easy to answer and those that are
• 2:46
  Speaker 1: harder to answer. Questions about the deep nature of the universe,
• 2:49
  Speaker 1: questions about what's out there, questions about how it all works,
• 2:53
  Speaker 1: and questions about who else might be out there in
• 2:56
  Speaker 1: the universe. Orge can't be with us today, but I'm
• 2:59
  Speaker 1: very please to have Kelly here to talk to us
• 3:01
  Speaker 1: about aliens landing on Earth and potentially sending our parasites
• 3:05
  Speaker 1: out to alien planets.
• 3:06
  Speaker 2: Oh is this the world needs more parasites. I'm so excited.
• 3:09
  Speaker 2: The universe needs more parasites, not just the world share them?
• 3:15
  Speaker 2: No know, is that a weird take? I don't.
• 3:18
  Speaker 1: I'll admit I have a hard time getting warm and
• 3:20
  Speaker 1: fuzzies for parasites. I always think of those wasps that
• 3:23
  Speaker 1: like lay their eggs inside spiders and then control them
• 3:26
  Speaker 1: until they die, driving them around like some horrific bumper car. Like,
• 3:30
  Speaker 1: oh man, that is just not a warm and fuzzy
• 3:32
  Speaker 1: oh I.
• 3:33
  Speaker 2: Love watching videos of that. It's it's so creepy and
• 3:36
  Speaker 2: like usually, so I have to admit, even though I'm
• 3:39
  Speaker 2: a biologist, and I might take my biologist card away
• 3:41
  Speaker 2: for saying this, I find spiders a little creepy. I
• 3:45
  Speaker 2: said it, but I almost feel bad for them when
• 3:48
  Speaker 2: I see them getting parasitized and like manipulating their web
• 3:51
  Speaker 2: building behavior and then the babies like stick a straw
• 3:54
  Speaker 2: in the back of the spiders and and it's it's
• 3:58
  Speaker 2: kind of creepy. I feel bad for spiders sometimes they
• 4:00
  Speaker 2: have my sympathy.
• 4:02
  Speaker 1: And you know, if we could have those wasps on
• 4:04
  Speaker 1: the podcast and we would ask them, like, how do
• 4:05
  Speaker 1: you feel about zombifying those spiders, they would answer with
• 4:08
  Speaker 1: the same cold, calculating quickness that you answered when you
• 4:12
  Speaker 1: said you would chop me up on the podcast. There
• 4:14
  Speaker 1: would be like, no problem, let's do it.
• 4:16
  Speaker 2: Yeah. Well, so, fortunately for me, I am a low
• 4:19
  Speaker 2: on introspection ability, so I'm not going to think too
• 4:22
  Speaker 2: hard about what that says about me. But I am
• 4:24
  Speaker 2: super glad that I am not the kind of organism
• 4:27
  Speaker 2: that wasps can manipulate life. Is good being a human,
• 4:31
  Speaker 2: or at least being a human in North America.
• 4:33
  Speaker 1: Until those alien wasps land here on Earth. And it's
• 4:36
  Speaker 1: a regular trope in science fiction that if you go
• 4:40
  Speaker 1: out into space you might catch some sort of weird
• 4:42
  Speaker 1: alien virus which takes over and infects the entire biome,
• 4:46
  Speaker 1: polluting the Earth and demolishing life on Earth. Or if
• 4:49
  Speaker 1: we land on Mars, we could accidentally pollute Mars with
• 4:52
  Speaker 1: some sort of Earth based microbe. This question of keeping
• 4:56
  Speaker 1: things sterile, of keeping things separate is a standard issue
• 4:59
  Speaker 1: in science fic and also in real life space missions.
• 5:03
  Speaker 2: Yeah, we go to great lengths to try to make
• 5:05
  Speaker 2: sure we don't do what's called forward contamination getting Earth
• 5:08
  Speaker 2: microbes out on Mars. And then we were very careful
• 5:12
  Speaker 2: to make sure that, you know, when the astronauts came
• 5:13
  Speaker 2: back from the Moon, there was no backwards contamination. They
• 5:16
  Speaker 2: didn't bring any microbes back from the Moon. And so
• 5:18
  Speaker 2: far I think we've had pretty good success. But if
• 5:20
  Speaker 2: I had to bet, I would bet some of our
• 5:23
  Speaker 2: extremophiles have made it to Mars. Do you know Daniel
• 5:25
  Speaker 2: has anybody? Uh, surely someone's looked.
• 5:27
  Speaker 1: At that I know that there are Tarte grades that
• 5:30
  Speaker 1: crash landed on the Moon in that Israeli experiment gone bad,
• 5:33
  Speaker 1: and they're probably busy building a colony up there and
• 5:35
  Speaker 1: planning to return with weapons. Yeah, that's pure speculation, of course. Yeah,
• 5:43
  Speaker 1: I feel like I have to say that, since this
• 5:44
  Speaker 1: is supposed to be a heavy science podcast, anytime we
• 5:46
  Speaker 1: say something silly, I want to make sure people know
• 5:48
  Speaker 1: when we're joking. But in terms of sending things to Mars,
• 5:53
  Speaker 1: you know, we have sent stuff from here to Mars,
• 5:56
  Speaker 1: and we have done our best to cleanse it of microbe.
• 6:00
  Speaker 1: But my wife is a microbiologist, and she always tells
• 6:02
  Speaker 1: me it's essentially impossible to remove microbes. I mean, you
• 6:06
  Speaker 1: will find microbes in every environment on Earth because there's
• 6:10
  Speaker 1: always some little critter capable of eating whatever poison you're
• 6:13
  Speaker 1: using to cleanse it of microbes. So I'd be very
• 6:16
  Speaker 1: skeptical that our landers have no microbes on them. So,
• 6:20
  Speaker 1: since I happen to be married to a microbiologist, I
• 6:22
  Speaker 1: thought it'd be fun to ask Katrina about it directly,
• 6:25
  Speaker 1: and so I did. So. Welcome to the podcast, Katrina,
• 6:29
  Speaker 1: Thanks very much for joining us.
• 6:30
  Speaker 3: Thanks for having me and thanks.
• 6:32
  Speaker 1: For contributing your biochemical expertise. Oh boy, So my first
• 6:36
  Speaker 1: question is what are the chances that we have already
• 6:39
  Speaker 1: polluted Mars and the Moon with microbes from Earth?
• 6:43
  Speaker 4: What a great question, and you know there are teams
• 6:45
  Speaker 4: of people who are devoting their life work to figuring
• 6:47
  Speaker 4: this out.
• 6:48
  Speaker 3: So you know you're asking me as a bystander to
• 6:50
  Speaker 3: answer that question.
• 6:51
  Speaker 4: But there have been some fascinating experiments where people, for example,
• 6:55
  Speaker 4: have found that up at JPL in Pasadena, California, they
• 6:59
  Speaker 4: use these really stringent cleaning reagents to try to remove
• 7:03
  Speaker 4: all the microbes from the surface of the spacecraft, and
• 7:06
  Speaker 4: they find that there are microbes that can actually eat
• 7:08
  Speaker 4: the most difficult cleaning reagent. You can imagine, it's like
• 7:12
  Speaker 4: bleach yum carbon source. They'll eat that. So what are
• 7:16
  Speaker 4: the chances that one of those microbes that survived JPL's
• 7:21
  Speaker 4: most atrocious molecules they could think of to kill all
• 7:24
  Speaker 4: the microbes and then also survived getting out of the
• 7:28
  Speaker 4: atmosphere of Earth and the transport to Mars. What do
• 7:31
  Speaker 4: I think the chances are? I think it's possible. Yeah,
• 7:34
  Speaker 4: I'm not saying these are like happy dividing cells.
• 7:38
  Speaker 3: Of microbes.
• 7:38
  Speaker 4: It's just that microbes have first of all, the most
• 7:41
  Speaker 4: diverse strategies you could imagine, so there's every time you
• 7:45
  Speaker 4: got an idea, they've got a million more. And then
• 7:47
  Speaker 4: they can form these very dormant sporelike or spore particles
• 7:53
  Speaker 4: that basically you know, squirrel away and hide their DNA inside.
• 7:58
  Speaker 3: Of like many, many many layers of protection.
• 8:01
  Speaker 4: So I think it's very possible that something in that
• 8:04
  Speaker 4: type of form. Ironically, the attempts to clean the spacecraft
• 8:08
  Speaker 4: could actually select for microbes that are really extra tough,
• 8:12
  Speaker 4: and therefore they would have a better chance of having
• 8:14
  Speaker 4: made it to Mars. Now, I'm not saying that when
• 8:16
  Speaker 4: they get to Mars then they're going to be like
• 8:19
  Speaker 4: stretching out, jumping in the pool, having a great life.
• 8:22
  Speaker 4: I mean, they're still going to be stuck in their
• 8:24
  Speaker 4: dormant state. But is it possible that if you like
• 8:27
  Speaker 4: brought some water to Mars and then it could like
• 8:30
  Speaker 4: wake those bugs up, you know, that kind of thing
• 8:32
  Speaker 4: could happen.
• 8:33
  Speaker 2: Yeah, But so I guess the second question is if
• 8:35
  Speaker 2: it can, so, it would need to survive the chemicals
• 8:39
  Speaker 2: the vacuum of space, and then find something to eat.
• 8:42
  Speaker 2: On Mars, and that's a lot of hoops to jump through.
• 8:44
  Speaker 2: You'd need a lot of variability in the microbes that
• 8:46
  Speaker 2: make it to Mars. But you know, if Jurassic Park
• 8:49
  Speaker 2: taught me anything it's that life finds a way.
• 8:55
  Speaker 1: Exactly. Katrina is always telling me. Like you pick up
• 8:57
  Speaker 1: a scoop of like boiling acidic water near some vent,
• 9:01
  Speaker 1: you'll find like ten to the nine bacteria in every
• 9:03
  Speaker 1: cubic centimeter. Or if you look at some satellite we're
• 9:05
  Speaker 1: sending up into space, you'll find microbes on the outside
• 9:08
  Speaker 1: that eat the bleach they were using to kill the microbes.
• 9:11
  Speaker 1: But you're right, those microbes have survived that environment. That
• 9:14
  Speaker 1: doesn't guarantee that they're going to be able to survive
• 9:16
  Speaker 1: any arbitrary environment. These extremo files are evolved to live
• 9:20
  Speaker 1: in their particular niches.
• 9:22
  Speaker 2: So should we stop trying?
• 9:23
  Speaker 1: I think we should just give up on the whole
• 9:25
  Speaker 1: field of biochemistry. I mean, that's what that's what I think.
• 9:29
  Speaker 2: That's how I felt when I was in college.
• 9:31
  Speaker 1: No, I think it is important that we try to
• 9:33
  Speaker 1: separate these things. I mean, imagine we land on Mars
• 9:36
  Speaker 1: and we discover microbes there. We want to know, are
• 9:39
  Speaker 1: these Earth microbes or not? And even if they have
• 9:43
  Speaker 1: Earth like DNA, we want to know did these come
• 9:46
  Speaker 1: from Earth or maybe all of life on Earth came
• 9:49
  Speaker 1: from microbes on Mars that were blasted off the surface.
• 9:52
  Speaker 1: That's an actually legitimate, non joking scientific theory about the
• 9:55
  Speaker 1: potential origin of life on Earth. So we want to
• 9:58
  Speaker 1: know if we've infected life on Mars.
• 10:01
  Speaker 2: So I know that we have bits of like Mars
• 10:04
  Speaker 2: that have been blown out into space and I think
• 10:06
  Speaker 2: they've landed, and like being able to find them in Antarctica.
• 10:09
  Speaker 2: Have we looked for alien microbes in those and found
• 10:12
  Speaker 2: anything yet?
• 10:13
  Speaker 1: Oh, we definitely have looked for alien microbes, And a
• 10:16
  Speaker 1: few decades ago there were scientists who were confident they
• 10:18
  Speaker 1: had found them. They saw these little microtubules, and even
• 10:21
  Speaker 1: President Clinton made this huge announcement, like on the lawn
• 10:24
  Speaker 1: of the White House, that we thought we had found
• 10:26
  Speaker 1: life on Mars. These days, though, we have other non
• 10:30
  Speaker 1: life based explanations for those formations, so people are pretty
• 10:33
  Speaker 1: convinced that's not evidence for life on Mars. But you know,
• 10:36
  Speaker 1: we've gotten like a few rocks from Mars that we
• 10:39
  Speaker 1: could study here on Earth, And so it's a pretty
• 10:42
  Speaker 1: small sample. We're hoping in the next decade or so
• 10:44
  Speaker 1: to do Mars sample return. Would they pick up rocks
• 10:47
  Speaker 1: from the surface of Mars and send them back here
• 10:49
  Speaker 1: to Earth via some ridiculously complicated Rube Goldberg set of devices.
• 10:54
  Speaker 1: But we're all excited to study those and maybe define
• 10:56
  Speaker 1: microbes there that would be exciting.
• 10:58
  Speaker 2: I hope we can contain them and they don't take
• 11:00
  Speaker 2: over our minds.
• 11:02
  Speaker 1: But we can also think beyond our Solar system and
• 11:04
  Speaker 1: wonder what about microbes on planets around other stars? Do
• 11:08
  Speaker 1: we need to take the same sort of considerations about
• 11:10
  Speaker 1: avoiding polluting exoplanets or maybe we should turn the question
• 11:14
  Speaker 1: on its head and on purpose pollute those exoplanets with
• 11:18
  Speaker 1: our kind of life.
• 11:19
  Speaker 2: You know. I feel like maybe we shouldn't have two
• 11:22
  Speaker 2: scientists talking about this, we should have like a philosopher
• 11:25
  Speaker 2: slash ethicist. But we've got what we've got, So what's up.
• 11:29
  Speaker 2: We don't have anybody with an ethical compass here, so
• 11:32
  Speaker 2: let's plow forward with this question.
• 11:34
  Speaker 1: But fortunately we do. We got a question from a listener, Haley,
• 11:37
  Speaker 1: who is nine years old, and she's young enough to
• 11:40
  Speaker 1: have sort of like an intuitive philosopher's heart and sense
• 11:43
  Speaker 1: of ethics at least, And so she wrote in with
• 11:46
  Speaker 1: this question him.
• 11:47
  Speaker 5: My name is Haley, I'm nine years old and today's
• 11:50
  Speaker 5: my birthday. I was actually wondering, if human wanted to
• 11:55
  Speaker 5: live after ours was gone, can't you put like micros
• 11:59
  Speaker 5: and back to on a different planet and let them
• 12:04
  Speaker 5: evolve there? And I was wondering, do you think astronauts
• 12:11
  Speaker 5: accidentally bring little small form like life forms to out
• 12:17
  Speaker 5: of Earth and put them somewhere else, like on their
• 12:21
  Speaker 5: clothes or the rockets by accident?
• 12:24
  Speaker 2: Thanks Hailey, those questions are so great and happy belated birthday, And.
• 12:32
  Speaker 1: How sad is it that we have to rely on
• 12:34
  Speaker 1: nine year olds to be our ethical compass.
• 12:36
  Speaker 2: Yeah? No, I think when my kids grow up, it's
• 12:38
  Speaker 2: gonna be uh, it's gonna be everyone for themselves here.
• 12:41
  Speaker 1: So I thought this was a really fun question, and
• 12:43
  Speaker 1: I started looking into it, and I discovered that there's
• 12:45
  Speaker 1: a whole project, a whole group of people with specific
• 12:49
  Speaker 1: plans and ideas to do just this, to send our microups,
• 12:53
  Speaker 1: our bacteria two different planets around other stars and to
• 12:57
  Speaker 1: see them with life, And is.
• 13:00
  Speaker 2: The goal so that you can make those habitats more
• 13:03
  Speaker 2: hospitable if humans ever decide they want to move there
• 13:05
  Speaker 2: or are they just doing it like as a fun
• 13:09
  Speaker 2: you know, and end equals too for like the possible
• 13:12
  Speaker 2: pass evolution could take.
• 13:16
  Speaker 1: You're asking me if they're being responsible or if they're
• 13:18
  Speaker 1: just like mucking around out of curiosity.
• 13:20
  Speaker 2: No, they're pretty clearly mucking around. But I want to
• 13:23
  Speaker 2: know how they justify the exercise.
• 13:26
  Speaker 1: Well, that's exactly what we're gonna be talking about today
• 13:29
  Speaker 1: as we answer the question could we seed exoplanets with
• 13:38
  Speaker 1: basic life?
• 13:40
  Speaker 2: Well, we should see what the listeners have to say.
• 13:42
  Speaker 1: Thank you very much to our group of listeners who
• 13:44
  Speaker 1: answer these random and sometimes weird questions. We love hearing
• 13:48
  Speaker 1: what you have to say and hearing your voice on
• 13:50
  Speaker 1: the podcast. If you'd like to be part of this
• 13:52
  Speaker 1: not very select group of lead volunteers, please write to
• 13:56
  Speaker 1: me to Questions at Danielandjorge dot com. Everybody is welcome.
• 14:00
  Speaker 1: Think about it for a minute. Do you think we
• 14:02
  Speaker 1: could seed exoplanets with basic life? Here's what people had
• 14:06
  Speaker 1: to say.
• 14:07
  Speaker 6: I reckon we could seed life on an exoplanet if
• 14:09
  Speaker 6: if the environment was suitably similar to Earth and there
• 14:11
  Speaker 6: was some kind of energy source for the life to
• 14:13
  Speaker 6: capitalize on. I imagine it would require a little bit
• 14:16
  Speaker 6: of engineering of the life unless we got very, very
• 14:18
  Speaker 6: lucky with the environment.
• 14:19
  Speaker 1: I believe it may be possible to see exoplanets with life. However,
• 14:23
  Speaker 1: I don't think we're anywhere near that capability. Were probably
• 14:27
  Speaker 1: many centuries of that millennia away from that.
• 14:29
  Speaker 7: I think that if an exoplanet has no existing life,
• 14:32
  Speaker 7: then seeding life should be possible. But if there's anything
• 14:35
  Speaker 7: there already, then the differences in proteins and whatever else
• 14:40
  Speaker 7: it may have developed there would mean that it would
• 14:44
  Speaker 7: be pretty unlikely without wiping out whatever was.
• 14:45
  Speaker 8: Their first I think we could, although precisely sending a
• 14:50
  Speaker 8: rocket to an exoplanet would be really tricky. But should
• 14:53
  Speaker 8: we Maybe while trying to seed life, we may end
• 14:57
  Speaker 8: up disrupting already existing ecosystems.
• 15:00
  Speaker 9: Yes, I think we can if the exoplanet has the
• 15:04
  Speaker 9: right habital conditions, and you could maybe put the organism
• 15:10
  Speaker 9: of the life on the planet. So I think yes.
• 15:14
  Speaker 2: I was impressed by all the different angles the listeners
• 15:17
  Speaker 2: came up with to address this question, like, well, it's
• 15:20
  Speaker 2: really far away, is that going to be a problem?
• 15:22
  Speaker 2: You know what would the environment need to be like
• 15:25
  Speaker 2: for them to survive? Lots of cool ideas from the
• 15:27
  Speaker 2: listeners on this one.
• 15:28
  Speaker 1: Yeah, exactly, lots of different scenarios. Can we get it there?
• 15:32
  Speaker 1: Would it survive? Why should we even do it? And
• 15:34
  Speaker 1: so I think we should start with your question there, Kelly,
• 15:37
  Speaker 1: But like, what is the motivation here exactly? Like why
• 15:40
  Speaker 1: would you build a little rocket, put a bunch of
• 15:42
  Speaker 1: bactery in it and send it to an exoplanet? What
• 15:44
  Speaker 1: exactly is the goal you're trying to achieve?
• 15:46
  Speaker 2: I mean, so, I personally am a big fan of life,
• 15:50
  Speaker 2: and I'd like there to be lots of life and
• 15:52
  Speaker 2: lots of biology everywhere. But I feel like it's complicated
• 15:56
  Speaker 2: when you get to adding biology to places that it
• 15:58
  Speaker 2: doesn't necessarily belong. I don't like invasive species very much
• 16:01
  Speaker 2: here on Earth and like less of that. So are
• 16:05
  Speaker 2: we like doing the ultimate experiment in invasive species?
• 16:10
  Speaker 1: I think there are lots of possible angles here. I
• 16:13
  Speaker 1: think maybe the most generous motivations are just the ones
• 16:17
  Speaker 1: you expressed, Like life is awesome, Let's have more of
• 16:20
  Speaker 1: it in the universe. So imagine you could find some
• 16:24
  Speaker 1: currently sterile planet where there is no life, and your
• 16:27
  Speaker 1: confident life would not arise naturally, why not see it
• 16:30
  Speaker 1: with life, turn it into a petri dish, see what
• 16:33
  Speaker 1: would happen, and potentially creating biomes that might be habitable
• 16:36
  Speaker 1: for humans in a deep, deep future. Now, way, you
• 16:39
  Speaker 1: wouldn't be displacing any current life, so you don't have
• 16:41
  Speaker 1: to worry about the ethics of like invasive species and colonialism.
• 16:45
  Speaker 2: But so that assumption is a really hard one for
• 16:48
  Speaker 2: me to accept though. So, like, you know, we are
• 16:50
  Speaker 2: not even one hundred percent sure that there's no life
• 16:53
  Speaker 2: on Mars. You know, it might still be in like
• 16:55
  Speaker 2: the lava tubes or something sort of like hiding out.
• 16:57
  Speaker 2: So it's even harder for us to study far out exoplanets.
• 17:02
  Speaker 2: How could we ever convince ourselves that a planet is
• 17:06
  Speaker 2: sterile and definitely doesn't have life when we only know
• 17:08
  Speaker 2: what life looks like on our planet and we can't
• 17:11
  Speaker 2: even tell you if there's life on the planets in
• 17:13
  Speaker 2: our Solar System. So I would have trouble believing we
• 17:16
  Speaker 2: could ever get certainty about that assumption. But what do
• 17:18
  Speaker 2: you think?
• 17:19
  Speaker 1: No, I agree with you, And it sounds like the
• 17:21
  Speaker 1: set of for a science fiction novel where scientists get
• 17:23
  Speaker 1: humbled because they didn't understand what life could be. Then
• 17:26
  Speaker 1: they marched forward with their hubrisk too quickly. I agree,
• 17:29
  Speaker 1: we don't know what life could be like in the universe,
• 17:32
  Speaker 1: so it's hard to be certain that any planet really
• 17:34
  Speaker 1: is sterile. It's also basically impossible to be certain that
• 17:37
  Speaker 1: if planet will always be sterile. What if life was
• 17:39
  Speaker 1: going to evolve next week and then you showed up
• 17:41
  Speaker 1: with your zillions of microbes and you now made it impossible.
• 17:45
  Speaker 1: That's not something you can ever probe, right, especially because
• 17:48
  Speaker 1: we don't know how common life is and how likely
• 17:51
  Speaker 1: it is to be created from non living environments. So
• 17:54
  Speaker 1: it definitely would be taking a gamble. But I think
• 17:56
  Speaker 1: the motivations are the ones we expressed earlier. It's just like,
• 17:59
  Speaker 1: wouldn't it be nice to have more life? Imagine if
• 18:01
  Speaker 1: we are the only life in the galaxy and there
• 18:04
  Speaker 1: are all these habitable worlds out there with nothing on them,
• 18:07
  Speaker 1: that does feel like kind of a waste.
• 18:09
  Speaker 2: It does, And you know, some of my favorite life
• 18:12
  Speaker 2: is life that I can eat. And so after the break,
• 18:17
  Speaker 2: let's talk about whether or not we can create essentially
• 18:20
  Speaker 2: grocery stores on other exoplanets. In case we ever decide
• 18:24
  Speaker 2: to go shopping there. Okay, so we all agree life
• 18:40
  Speaker 2: is awesome, and as long as we're not wiping out
• 18:43
  Speaker 2: other life, it might be cool if there were more
• 18:45
  Speaker 2: life in other places and we could sort of see
• 18:47
  Speaker 2: what kind of amazing biodiversity ends up being created in
• 18:50
  Speaker 2: new environments. But let's talk about being able to eat
• 18:53
  Speaker 2: that biodiversity. So, say we were seeding other planets in
• 18:57
  Speaker 2: case humans ever come along, what do you think I
• 19:00
  Speaker 2: think the chances are that you see to planet, Like,
• 19:02
  Speaker 2: how long do you need to wait before you can
• 19:04
  Speaker 2: harvest it?
• 19:04
  Speaker 1: Yeah, that's a great question because I think you've pointed
• 19:07
  Speaker 1: out to me many times and it's described in your
• 19:10
  Speaker 1: upcoming book. If we do land on another planet, we
• 19:13
  Speaker 1: need to find some way to be self sufficient. You
• 19:15
  Speaker 1: can't rely on like shipments from Earth forever, which means
• 19:19
  Speaker 1: you need to be able to create your food locally,
• 19:21
  Speaker 1: which means you need like a whole biome. You need
• 19:23
  Speaker 1: like plants, and you need microbes. You need all this
• 19:26
  Speaker 1: stuff to create your life, and that's difficult to arrive with.
• 19:29
  Speaker 1: So it'd be wonderful if you showed up and there's
• 19:32
  Speaker 1: like plants or at least microbes or you know, the
• 19:35
  Speaker 1: basic foundation of your ecosystem that you could build your
• 19:39
  Speaker 1: grocery stores on top of. And so in a few
• 19:42
  Speaker 1: minutes you'll hear an interview I did with a microbiologist
• 19:45
  Speaker 1: where asked them essentially that question, like how long would
• 19:47
  Speaker 1: it take to go from injecting bacteria into an ocean
• 19:51
  Speaker 1: to showing up and finding redwoods and dinosaurs, you know,
• 19:54
  Speaker 1: things that you could hunt and climb around on and eat.
• 19:57
  Speaker 1: And so you'll hear him say it's a very, very
• 19:59
  Speaker 1: long time. It's not something you could expect to do
• 20:01
  Speaker 1: in a million years, or maybe even in a billion years.
• 20:04
  Speaker 1: But you know, on this podcast, we are very forward thinking.
• 20:07
  Speaker 1: We are not just planning for our children and our
• 20:09
  Speaker 1: children's children. We're planning for the deep future of humanity, right.
• 20:14
  Speaker 2: Infinite time horizons. Nothing here limits us.
• 20:18
  Speaker 1: Which means we can ask for infinite budgets, right, I mean,
• 20:21
  Speaker 1: because like a dollar today is worth so much more
• 20:24
  Speaker 1: in the future. But I think the picture you should
• 20:26
  Speaker 1: have in your mind is the Earth is the only
• 20:29
  Speaker 1: place in the galaxy with life, or one a few places.
• 20:32
  Speaker 1: If life in the galaxy is rare and it takes
• 20:35
  Speaker 1: a long time to develop. Then it seems like an
• 20:38
  Speaker 1: attractive idea to take a little bundle of our microbes,
• 20:41
  Speaker 1: send it to another planet, have it developed life there,
• 20:44
  Speaker 1: because then it would be more life in the galaxy.
• 20:46
  Speaker 1: And also, as you say, it would be the kind
• 20:49
  Speaker 1: of life that we can eat, which is our favorite
• 20:51
  Speaker 1: kind of life, because you know, even if you show
• 20:53
  Speaker 1: up on an alien planet and it has some kind
• 20:55
  Speaker 1: of life, it's not guaranteed that you could eat it.
• 20:58
  Speaker 2: What I don't necessarily even though it's guaranteed if you
• 21:01
  Speaker 2: could eat it, if it was growing somewhere else. You know,
• 21:03
  Speaker 2: it's not safe for us to eat all the life
• 21:06
  Speaker 2: on Earth. There are definitely mushrooms that you ought not
• 21:08
  Speaker 2: to eat. For example. You know, I guess the question
• 21:10
  Speaker 2: would be like how often do you see the planet
• 21:13
  Speaker 2: and it doesn't take how often do you see the
• 21:15
  Speaker 2: planet but you come back and it's filled with toxic
• 21:17
  Speaker 2: mushrooms or something like that, And so, you know, I
• 21:19
  Speaker 2: think there's lots of ways this could go that might
• 21:22
  Speaker 2: not be exactly what you want, but I think all
• 21:24
  Speaker 2: of those ways would be interesting, would teach us something
• 21:26
  Speaker 2: cool if I can ethically, you know, jump the hurdle
• 21:29
  Speaker 2: of feeling comfortable with this experiment.
• 21:31
  Speaker 1: And you raise an important point earlier, which is like,
• 21:33
  Speaker 1: how do you know which planet is a good candidate
• 21:36
  Speaker 1: for sending your microbes? Which planets might have the right conditions,
• 21:39
  Speaker 1: or which planets might be sterile. And so there's a
• 21:42
  Speaker 1: group of folks it's called Project Genesis that have actually
• 21:45
  Speaker 1: thought this through and worked on a little bit of
• 21:48
  Speaker 1: the engineering to make this possible.
• 21:50
  Speaker 2: Oh, tell me more about that.
• 21:51
  Speaker 1: The idea is to do it in two stages. The
• 21:53
  Speaker 1: first is to send out a bunch of probes to
• 21:55
  Speaker 1: find good candidates, to gather data and beam it back.
• 21:58
  Speaker 1: So the first wave is like, go out there and
• 22:01
  Speaker 1: find planets in the galaxy which might be good candidates.
• 22:04
  Speaker 1: And then a second wave is to actually send the microbes.
• 22:08
  Speaker 1: And this is important because the first wave can be
• 22:10
  Speaker 1: a lot faster than the second wave because the first
• 22:12
  Speaker 1: wave doesn't have to stop at the planet. You can
• 22:15
  Speaker 1: just do like a quick fly by and see these.
• 22:18
  Speaker 2: Planets and then shoot the data back.
• 22:20
  Speaker 1: To us and shoot the data back. And this has
• 22:23
  Speaker 1: to do with the physics of interstellar travel. Right. All
• 22:26
  Speaker 1: of these stars, even the ones close to us in
• 22:28
  Speaker 1: the galaxy, are pretty far away, like the nearest star
• 22:31
  Speaker 1: is like four light years away, and the whole galaxy
• 22:34
  Speaker 1: is one hundred thousand light years across. So getting from
• 22:37
  Speaker 1: star to star takes a long time because it takes
• 22:40
  Speaker 1: you a long time to accelerate anywhere near the speed
• 22:42
  Speaker 1: of light. So even getting to the nearest star could
• 22:45
  Speaker 1: take you thousands of years, especially if you have to
• 22:48
  Speaker 1: bring with you all the fuel that it takes to accelerate,
• 22:52
  Speaker 1: and the more fuel you bring with you, the more
• 22:54
  Speaker 1: fuel you need because you have to accelerate all that fuel.
• 22:57
  Speaker 1: See very quickly, have extraordinarily expensive.
• 22:59
  Speaker 2: Rock, So even that first pass is not going to
• 23:02
  Speaker 2: get done in our lifetime. And I can imagine it
• 23:05
  Speaker 2: being super frustrating to like put a bunch of equipment
• 23:08
  Speaker 2: on there, and then five hundred years later you're like, oh,
• 23:11
  Speaker 2: we wish we had put this other piece of equipment
• 23:14
  Speaker 2: on there, but I guess you'd make do with what
• 23:15
  Speaker 2: you had. Are there options that don't require just like
• 23:19
  Speaker 2: ridiculous amounts of fuel.
• 23:21
  Speaker 1: There are some really clever options, and we've talked about
• 23:23
  Speaker 1: in the podcast once before. There's this plan for something
• 23:26
  Speaker 1: called a solar sale. The idea is, don't bring the
• 23:30
  Speaker 1: fuel with you, don't load up a rocket with fuel
• 23:32
  Speaker 1: and then need fuel to push that fuel and fuel
• 23:34
  Speaker 1: to push that fuel. Don't bring any fuel at all,
• 23:37
  Speaker 1: have all the power come from the sun and just
• 23:39
  Speaker 1: have a sale. The solar sale is just a huge
• 23:42
  Speaker 1: mirror and all the photons from the sun bounce off
• 23:45
  Speaker 1: of it and give it a little push. Photons are
• 23:47
  Speaker 1: these tiny little particles the quanta of light, and they
• 23:51
  Speaker 1: have no math to them, but they do have momentum,
• 23:54
  Speaker 1: which means when they bounce off of something and go
• 23:57
  Speaker 1: the other direction, they give that something a kick. Like
• 24:00
  Speaker 1: when you're standing in the sun, the sun is literally
• 24:03
  Speaker 1: pushing on you with all those photons. It's a very
• 24:06
  Speaker 1: gentle push, which is why the sun doesn't usually knock
• 24:08
  Speaker 1: you down except in southern California in July, but it
• 24:11
  Speaker 1: is there. And if you had a very lightweight spacecraft
• 24:14
  Speaker 1: and a very large sale, you could accelerate up to
• 24:17
  Speaker 1: near the speed of light pretty quickly.
• 24:19
  Speaker 2: That sounds like it's even faster than the method that
• 24:22
  Speaker 2: uses fuel.
• 24:23
  Speaker 1: Is that right, Yeah, exactly, it's much faster than the
• 24:25
  Speaker 1: method that uses fuel. The disadvantage is that there's no
• 24:29
  Speaker 1: way to slow down, like this thing can accelerate up
• 24:32
  Speaker 1: to near the speed of light and then it can
• 24:34
  Speaker 1: whiz by your planet very very quickly, but it could
• 24:38
  Speaker 1: take some pictures and it could send you some information.
• 24:40
  Speaker 1: That's why this first phase is just information gathering and
• 24:44
  Speaker 1: then beam you back the data of course at the
• 24:46
  Speaker 1: speed of light. So this first phase where you like
• 24:48
  Speaker 1: go out and look at planets, you say, like is
• 24:50
  Speaker 1: there oxygen on them? Is there water on them? What
• 24:53
  Speaker 1: is the basic environment? Like this could be a very
• 24:55
  Speaker 1: quick survey.
• 24:56
  Speaker 2: Okay, So if you're doing these surveys, what kind of
• 24:59
  Speaker 2: things are you looking for? I assume oxygen. Well, I
• 25:02
  Speaker 2: mean there's bacteria that don't require oxygen, but I guess
• 25:05
  Speaker 2: if the plant is you're seating it for food, you're
• 25:08
  Speaker 2: gonna want there to be oxygen for us. So probably
• 25:12
  Speaker 2: you want a planet with oxygen.
• 25:13
  Speaker 1: That is the first and the hardest question, like do
• 25:16
  Speaker 1: you want planets with oxygen or without oxygen? And it's
• 25:19
  Speaker 1: interesting to think about, like where planets do get their oxygen.
• 25:22
  Speaker 1: Are their planets out there that are sterile but have
• 25:24
  Speaker 1: oxygen or is oxygen purely just a product of life?
• 25:28
  Speaker 1: And it's interesting because actually most planets do have oxygen
• 25:32
  Speaker 1: on them very very early in their life cycle. Most
• 25:35
  Speaker 1: planets are made with water because water is everywhere in
• 25:37
  Speaker 1: the universe, and in the early phase of the life
• 25:40
  Speaker 1: cycle of a star, they tend to emit a lot
• 25:42
  Speaker 1: of ultraviolet radiation. This is part of their life cycle
• 25:45
  Speaker 1: called pre main sequence, like before they settle down and
• 25:48
  Speaker 1: really just doing all their steady burning effusion, they emit
• 25:51
  Speaker 1: a huge amount of ultraviolet radiation which can break up
• 25:55
  Speaker 1: that water and produce oxygen. So very early in the
• 25:59
  Speaker 1: life of a planet do get some natural oxygen without
• 26:02
  Speaker 1: any life right, so you can get planets with oxygen
• 26:05
  Speaker 1: on them. The problem is that for a lot of stars,
• 26:07
  Speaker 1: this early phase is not very long. It's just a
• 26:10
  Speaker 1: few tens of millions of years, so it doesn't make
• 26:13
  Speaker 1: very much oxygen. And because you're blowing off so much
• 26:16
  Speaker 1: solar radiation, a lot of the atmosphere of a planet
• 26:18
  Speaker 1: can just get blown off. And this is what happened
• 26:21
  Speaker 1: to Earth. We had a little bit of oxygen made
• 26:23
  Speaker 1: early on through this UV light from the Sun, but
• 26:26
  Speaker 1: then the Sun basically blew away our entire atmosphere that
• 26:28
  Speaker 1: was the one that was formed with the original planet.
• 26:31
  Speaker 2: Whoops. So then do we want to send do we
• 26:35
  Speaker 2: want to send photosynthesizing organisms.
• 26:38
  Speaker 1: Then well, it's an interesting question, right, Like on Earth,
• 26:42
  Speaker 1: life started without any oxygen because the atmosphere was replaced
• 26:46
  Speaker 1: by volcanic outgassing which got nygen and CO two, and
• 26:50
  Speaker 1: then photosynthesizing organisms did create oxygen. But it's interesting because
• 26:53
  Speaker 1: a lot of biochemists tell you that having oxygen makes
• 26:57
  Speaker 1: it harder to form life, Like a lot of the
• 26:59
  Speaker 1: chemical building blocks of life couldn't have formed if you
• 27:03
  Speaker 1: had a lot of oxygen in your atmosphere. That the
• 27:05
  Speaker 1: anaerobic procedures are actually more important and they're inhibited by
• 27:09
  Speaker 1: the presence of oxygen. So if what you want is
• 27:12
  Speaker 1: to start life on a sterile planet, you probably don't
• 27:15
  Speaker 1: want oxygen. But if you want to seed it with
• 27:18
  Speaker 1: life like hours, then probably you do want to find
• 27:22
  Speaker 1: oxygen rich planets because they're more conducive to our kind
• 27:26
  Speaker 1: of life, and they're probably sterile because the oxygen is
• 27:29
  Speaker 1: like poisoned to those early forms of life.
• 27:32
  Speaker 2: So how do you know that the planet you're seating
• 27:35
  Speaker 2: hasn't like progressed as far as Earth and that's why
• 27:38
  Speaker 2: it's got oxygen? I guess because your flyby was that accurate.
• 27:42
  Speaker 1: Yeah, on the flyby, you're going to do more than
• 27:44
  Speaker 1: just test for water and test for oxygen. You can
• 27:46
  Speaker 1: also look for methane, for example. Methane and oxygen together
• 27:50
  Speaker 1: are a pretty good signature of life. You know, you
• 27:53
  Speaker 1: can look for phosphine. It's a whole really difficult question
• 27:56
  Speaker 1: of like how do you know if there's life on
• 27:58
  Speaker 1: that planet? But I think in general, looking for oxygen
• 28:01
  Speaker 1: rich planets that don't have obvious signs of life is
• 28:04
  Speaker 1: a good target because oxygen tends to prohibit the formation
• 28:08
  Speaker 1: of early life. And it turns out it actually is
• 28:10
  Speaker 1: possible to have planets with lots of oxygen that isn't
• 28:14
  Speaker 1: produced by photosynthesis.
• 28:15
  Speaker 2: And where do we get it from?
• 28:17
  Speaker 1: So there are a few different ways that planetary scientists
• 28:19
  Speaker 1: think that it's possible to have a bunch of oxygen
• 28:22
  Speaker 1: on your planet and not have it be blown away
• 28:24
  Speaker 1: in the early life cycle of the star and not
• 28:26
  Speaker 1: have it come from photosynthesizing life. There's a few different
• 28:30
  Speaker 1: configurations that at least their models tell them this can happen.
• 28:33
  Speaker 1: In like, if you have a planet that has a
• 28:35
  Speaker 1: huge amount of water, like a water world, then all
• 28:39
  Speaker 1: that water will put pressure on the crust of that planet,
• 28:42
  Speaker 1: which basically shuts down the geologic activity like all the
• 28:44
  Speaker 1: plate tectonics and the volcanism that we have, and it
• 28:48
  Speaker 1: slows down the weathering and the melting of the rock.
• 28:51
  Speaker 1: Both of these things absorb oxygen from the atmosphere, and
• 28:54
  Speaker 1: so if you have a huge amount of water, you
• 28:56
  Speaker 1: can shut down these sort of like oxygen slurping mechanism.
• 29:00
  Speaker 1: Like you know, rocks out there on our planet have
• 29:02
  Speaker 1: rusted because they have oxygenated. All the weathering of rocks
• 29:06
  Speaker 1: on the surface of the Earth has slurped a huge
• 29:08
  Speaker 1: amount of oxygen out of our atmosphere. So if you
• 29:11
  Speaker 1: have a planet where you basically suppress the oxygen slurping mechanisms,
• 29:15
  Speaker 1: then you can maintain some of the oxygen in the atmosphere.
• 29:18
  Speaker 1: That's sort of like one mechanism to make an oxygen
• 29:21
  Speaker 1: rich exoplanet without life on it.
• 29:23
  Speaker 2: So to get an oxygen rich exoplanet without life, you
• 29:26
  Speaker 2: can do it by having tons and tons and tons
• 29:29
  Speaker 2: and tons and tons of water. Can you get more
• 29:31
  Speaker 2: dry versions or does it always have to have loads
• 29:33
  Speaker 2: of water?
• 29:34
  Speaker 1: Yeah, exactly, you can. The sort of desert planet can
• 29:37
  Speaker 1: also do that. If you have a little water, but
• 29:38
  Speaker 1: not in zero. Then you end it with like a
• 29:40
  Speaker 1: solid surface and a lot of steam in the atmosphere.
• 29:44
  Speaker 1: It gets very very hot, and all the water becomes vapor.
• 29:47
  Speaker 1: It provides this like big reservoir of oxygen in the atmosphere,
• 29:51
  Speaker 1: and then the sunlight breaks if the water molecules, the
• 29:54
  Speaker 1: hydrogen floats off to space because it's very light, and
• 29:56
  Speaker 1: the oxygen sticks around. And if the planet has like
• 30:00
  Speaker 1: a solid desert surface, it can't weather, it can't absorb
• 30:03
  Speaker 1: that oxygen, so then the oxygen stays in the atmosphere.
• 30:06
  Speaker 1: So you have either like water World or a desert
• 30:09
  Speaker 1: planet with like a steamy atmosphere.
• 30:11
  Speaker 2: All right, is there anything in between? Or those are
• 30:14
  Speaker 2: the two ways you get high oxygen environments.
• 30:16
  Speaker 1: There is one other speculation. If you have a planet
• 30:18
  Speaker 1: that has like a very high initial ratio of carbon
• 30:22
  Speaker 1: dioxide to water, then you end up with a runaway
• 30:24
  Speaker 1: greenhouse effect, sort of like Venus. It gets super duper hot,
• 30:28
  Speaker 1: and you have no oceans because all the water is
• 30:31
  Speaker 1: turned into steam, and you have no volatiles in the
• 30:34
  Speaker 1: planet's mental because it's too hot. These voltules would do
• 30:36
  Speaker 1: the same thing of like sequestering all the planetary oxygen
• 30:39
  Speaker 1: through chemical reactions. Instead, the voltules are now in the
• 30:42
  Speaker 1: atmosphere where they're unable to remove the oxygen. They're having
• 30:45
  Speaker 1: a really significant runaway greenhouse effect. Is another way to
• 30:48
  Speaker 1: suppress some of the oxygen slurping mechanisms that would normally
• 30:52
  Speaker 1: remove oxygen from an atmosphere. So either you have a
• 30:56
  Speaker 1: water world or a desert planet, or you have like
• 30:58
  Speaker 1: a crazy venous green house effect.
• 31:00
  Speaker 2: Well, frankly, I don't want to live in any of
• 31:02
  Speaker 2: those environments, so I'm hoping whatever microbes we dump makes
• 31:06
  Speaker 2: everything a lot nicer, much longer. After let's take a
• 31:09
  Speaker 2: break and then we'll talk about one other nice option
• 31:12
  Speaker 2: for where we could be seeding our microbes. Okay, so
• 31:28
  Speaker 2: there's one other nice option for places we could see.
• 31:32
  Speaker 2: Maybe maybe there's more than one, but one that we're
• 31:34
  Speaker 2: going to talk about today, And those are planets that
• 31:36
  Speaker 2: have these short windows of time as they're sort of
• 31:40
  Speaker 2: developing and going along where they might be a nice
• 31:42
  Speaker 2: place to seed with earthy microbes. Could you tell us
• 31:45
  Speaker 2: about that?
• 31:45
  Speaker 1: Yeah, I remember. The big idea is to look for
• 31:48
  Speaker 1: places where our life might survive, but life wouldn't grow
• 31:52
  Speaker 1: on its own. Where we're not displacing native life like
• 31:54
  Speaker 1: original species. So one idea is oxygen rich steroplanets because
• 31:59
  Speaker 1: the can prevents life from arising. The other is to
• 32:02
  Speaker 1: look for places where life doesn't have time to arise,
• 32:07
  Speaker 1: like it might be that there's enough time for us
• 32:08
  Speaker 1: to seed it with life, which could then take off,
• 32:11
  Speaker 1: but there aren't like the billions of years it would
• 32:13
  Speaker 1: take for life to start on its own. An example
• 32:16
  Speaker 1: of that are brown dwarf systems. Brown dwarf is a
• 32:20
  Speaker 1: star that's not hot enough to fuse the way that
• 32:22
  Speaker 1: our star does. It doesn't have enough mass, so there's
• 32:25
  Speaker 1: not enough internal temperature for fusing to kick off. So
• 32:27
  Speaker 1: they call these sometimes a failed star. They're just big
• 32:30
  Speaker 1: blobs of hot gas and they're hot, but they're not
• 32:33
  Speaker 1: fused and they're not glowing right. This does provide some
• 32:36
  Speaker 1: temperature to create a habitable region for your planet, and
• 32:39
  Speaker 1: it could remain habitable for like a few hundred million
• 32:42
  Speaker 1: years or a billion years, but not like a long
• 32:45
  Speaker 1: time the way that our Sun and our Earth has
• 32:47
  Speaker 1: many many billions of years as a window. So the
• 32:50
  Speaker 1: idea is to look for brown dwarf systems where life
• 32:54
  Speaker 1: could survive but maybe it doesn't have enough time to
• 32:56
  Speaker 1: develop on its own and seed planets in those systems.
• 33:00
  Speaker 1: It's a place where, like our life could again survive,
• 33:03
  Speaker 1: but we wouldn't be displacing any native species.
• 33:06
  Speaker 2: But so then we would need to move our life
• 33:08
  Speaker 2: somewhere else. I mean, I guess it would have millions
• 33:10
  Speaker 2: or billions of years, and so it would have some,
• 33:13
  Speaker 2: you know, time to run its course. But I mean,
• 33:15
  Speaker 2: is that enough time where we could imagine that something
• 33:18
  Speaker 2: we could eat could have developed, and that that would
• 33:20
  Speaker 2: be a useful run for the experiment.
• 33:23
  Speaker 1: Yeah, exactly. So you send our life there and it
• 33:26
  Speaker 1: has enough time to flourish and develop and do something
• 33:29
  Speaker 1: before we arrive and set up our grocery stores.
• 33:31
  Speaker 2: Okay, I know, I feel like there's still a part
• 33:34
  Speaker 2: of me that feels like it's enough time for our
• 33:36
  Speaker 2: seated microbes to do their thing. That should be enough
• 33:39
  Speaker 2: time for life to potentially arise on its own there.
• 33:43
  Speaker 2: So I'm not one hundred percent convinced that we wouldn't
• 33:45
  Speaker 2: be snuffing out some other possibility for the start of
• 33:48
  Speaker 2: life on another planet. But am I missing the point?
• 33:52
  Speaker 1: No, you're not at all. And I totally agree all
• 33:54
  Speaker 1: these calculations. Assume that life takes a long time to start,
• 33:58
  Speaker 1: and if it doesn't, if pretty quickly when there are
• 34:01
  Speaker 1: good conditions, then all these places potentially could have life
• 34:05
  Speaker 1: already or could start life any moment, right, And if
• 34:07
  Speaker 1: you see them on a Tuesday, you could be displacing
• 34:10
  Speaker 1: life which would have started on a Friday. And so
• 34:12
  Speaker 1: before we do this, we definitely need to understand that
• 34:14
  Speaker 1: a lot better before we're confident in saying like, oh,
• 34:17
  Speaker 1: this is a steril place and it's unlikely for life
• 34:20
  Speaker 1: to arise anyway.
• 34:21
  Speaker 2: Okay, so let's assume that we've convinced ourselves we found
• 34:24
  Speaker 2: a sterile place that we feel comfortable seating microbes. How
• 34:29
  Speaker 2: do we get the microbes there? I assume some of
• 34:32
  Speaker 2: the methods that we used to survey could also be
• 34:34
  Speaker 2: used to deliver microbes.
• 34:36
  Speaker 1: So it's a great question how do we deliver the microbes? Right?
• 34:39
  Speaker 1: Say you actually have this little blob of stuff and
• 34:41
  Speaker 1: you want to send it to a planet around Alpha
• 34:43
  Speaker 1: Centauri or something where we talked about earlier. The solar
• 34:46
  Speaker 1: sale is great for getting up to high speeds, but
• 34:49
  Speaker 1: it's not so great for breaking. You don't want your
• 34:51
  Speaker 1: microbes to hit the planet at like ninety five percent
• 34:53
  Speaker 1: of the speed of light, because then they'll just like
• 34:56
  Speaker 1: core sample the planet. Right. They need a gentle landing
• 34:59
  Speaker 1: if you're going to spurse them, sprinkle them on top
• 35:01
  Speaker 1: of the ocean. Right. So somehow you have to figure
• 35:04
  Speaker 1: out how to slow down. You don't just want to
• 35:07
  Speaker 1: accelerate and zoom through the system. You want to arrive
• 35:10
  Speaker 1: at a gentle speed.
• 35:11
  Speaker 2: How do you do that?
• 35:12
  Speaker 1: Yeah, it's tricky, But there's a really cool technology called
• 35:15
  Speaker 1: magnetic brakes, which are very similar to a technology that
• 35:19
  Speaker 1: you and I talked about in that science fiction novel
• 35:22
  Speaker 1: Orbital Cloud. Remember that they had this technology in that
• 35:24
  Speaker 1: book to maneuver satellites by using the Lorentz force. They
• 35:28
  Speaker 1: had these long space tethers, these long wires. If you
• 35:31
  Speaker 1: put a current on the wire, it would interact with
• 35:33
  Speaker 1: the magnetic field of the planet and put a force
• 35:36
  Speaker 1: on the object. It's a very similar idea here. The
• 35:39
  Speaker 1: physics is fundamentally the same, though the mechanism is a
• 35:42
  Speaker 1: little bit different. What you do is you bring a
• 35:44
  Speaker 1: loop of wire and you make a current. That current
• 35:47
  Speaker 1: makes a magnetic field, and you can use that magnetic
• 35:50
  Speaker 1: field as a break because space is actually filled with
• 35:53
  Speaker 1: stuff that you can push against. Because the Sun is
• 35:56
  Speaker 1: not just putting out photons, it's putting out protons. Part
• 35:59
  Speaker 1: of the solar wind are these charged particles, these protons
• 36:02
  Speaker 1: flying through space, And as you approach this distant system,
• 36:06
  Speaker 1: you can turn on this magnetic field which will push
• 36:09
  Speaker 1: back against all of these protons in a way to
• 36:12
  Speaker 1: slow you down.
• 36:13
  Speaker 2: Could you turn on the magnetic breaks from Earth? Like,
• 36:16
  Speaker 2: how do you make sure the breaks don't turn on
• 36:18
  Speaker 2: too soon?
• 36:20
  Speaker 1: I got no breaks, No breaks exactly. No, it's important
• 36:24
  Speaker 1: that you time this right. And yeah, you could turn
• 36:26
  Speaker 1: this on from Earth, or you could preprogram it to
• 36:28
  Speaker 1: know where it is, or you could detect a certain
• 36:31
  Speaker 1: level of protons. There's lots of various ways to turn
• 36:34
  Speaker 1: it on. But yeah, you could send this thing messages
• 36:37
  Speaker 1: which would catch up with it because it's not flying
• 36:38
  Speaker 1: at the speed of light, and so your photonic messages
• 36:41
  Speaker 1: from Earth could always catch it. Now, unlike a solar sale,
• 36:44
  Speaker 1: which people have built and tested, magnetic breaking is a
• 36:48
  Speaker 1: little bit more theoretical. Nobody's ever built one of these
• 36:50
  Speaker 1: things as far as I could tell, and demonstrated that
• 36:53
  Speaker 1: it could actually work out there in the environment of space.
• 36:56
  Speaker 1: But in principle, we have some ideas about how to
• 36:59
  Speaker 1: do this. How to send something they are really really
• 37:01
  Speaker 1: fast and slow it down in time to enter the system.
• 37:04
  Speaker 2: Okay, so let's assume that we can send something out
• 37:08
  Speaker 2: to our chosen exoplanet and we can stop it so
• 37:11
  Speaker 2: that we don't accidentally core the planet. Like, how do
• 37:14
  Speaker 2: you pick which microbes you send?
• 37:16
  Speaker 1: Yeah, that is a great question. What do you send?
• 37:19
  Speaker 1: How likely it is to survive? You send one thing?
• 37:21
  Speaker 1: Do you send ten thousand different things? You send more
• 37:24
  Speaker 1: of one than the other? How does this all work?
• 37:26
  Speaker 1: What do microbes need? Anyway? So I didn't know the
• 37:29
  Speaker 1: answers to these questions, so I called up a friend,
• 37:32
  Speaker 1: Will Ratcliffe. He's an evolutionary microbial biologist at Georgia Tech,
• 37:37
  Speaker 1: and he studies the evolution of multicellularity. Like how did
• 37:41
  Speaker 1: creators go from individual cells to working together as single organisms?
• 37:45
  Speaker 2: You have such interesting friends. Let's hear the interview.
• 37:50
  Speaker 1: So here's my chat with Will Ratcliffe. All right, so
• 37:55
  Speaker 1: then it's my pleasure to welcome to the podcast Professor
• 37:58
  Speaker 1: William Ratcliffe. Well, welcome to the podcast. Thanks very much
• 38:02
  Speaker 1: for joining us, Ah, thanks for having me. So will
• 38:04
  Speaker 1: we are talking about dropping a load of life on
• 38:08
  Speaker 1: some alien planet, some exoplanet, and I'm just wondering, like,
• 38:13
  Speaker 1: first of all, what are the chances of microbes surviving
• 38:17
  Speaker 1: If I take a bunch of stuff I've scraped out
• 38:20
  Speaker 1: of sewage here on Earth or you know, from underneath
• 38:23
  Speaker 1: some trees or something in a forest, and I launch
• 38:26
  Speaker 1: them to an alien planet. Are they just going to
• 38:28
  Speaker 1: dry up and die? What are the chances that they
• 38:30
  Speaker 1: can survive?
• 38:31
  Speaker 10: So the answer to this, I think really depends on
• 38:34
  Speaker 10: the existence of a few things. You need liquid water.
• 38:37
  Speaker 10: There's really kind of no getting around that. If you
• 38:39
  Speaker 10: have an exoplanet that doesn't have liquid water, ideally on
• 38:43
  Speaker 10: the surface, then it's going to be an uphill battle
• 38:46
  Speaker 10: for life. You might have things which persist but don't flourish,
• 38:50
  Speaker 10: but if you have liquid water, then it becomes a
• 38:52
  Speaker 10: question of what kind of energy sources and what kind
• 38:56
  Speaker 10: of carbon sources are available that for that life. We're
• 38:59
  Speaker 10: used to life that's sort of makes a living largely
• 39:01
  Speaker 10: either eating other things, which we do right. We take
• 39:04
  Speaker 10: large chains of carbon and break them down and get
• 39:07
  Speaker 10: both of our carbon, which is what we used to
• 39:09
  Speaker 10: build bodies and our energy, which is what we used
• 39:11
  Speaker 10: to power those bodies from those big chains of carbon.
• 39:14
  Speaker 1: But there's actually a lot of different niches.
• 39:16
  Speaker 10: That life has sort of evolved to take advantage of
• 39:18
  Speaker 10: and dissipate energetic equilibria and build bodies with carbon in
• 39:22
  Speaker 10: different ways. One that's really common and I think common
• 39:25
  Speaker 10: in the universe and really impactful is light, So you know, photosynthesis.
• 39:30
  Speaker 10: So being able to use light for energy is a
• 39:32
  Speaker 10: really common way of making a living because there's a
• 39:35
  Speaker 10: ton of energy in light and it's relatively straightforward for
• 39:38
  Speaker 10: organisms that have evolved the ability to use it to
• 39:40
  Speaker 10: just put it to work powering cells.
• 39:43
  Speaker 1: But didn't we have life on Earth for millions of
• 39:46
  Speaker 1: years before we had anybody taking energy from photons?
• 39:49
  Speaker 10: Yeah, it's a good question. It's actually it gets really
• 39:51
  Speaker 10: difficult to infer back that far. So we likely had
• 39:57
  Speaker 10: photosynthetic behavior pretty soon after the origin of life, although
• 40:01
  Speaker 10: again it's difficult to really see back beyond a couple
• 40:04
  Speaker 10: billion years. By two point one billion years ago, we
• 40:08
  Speaker 10: had had so much oxygen pumped into the atmosphere on
• 40:11
  Speaker 10: Earth that we oxidize our atmosphere and we have you know,
• 40:15
  Speaker 10: we basically couldn't absorb and react away any more of it.
• 40:17
  Speaker 10: But life arose around three and a half billion years ago.
• 40:20
  Speaker 10: But you're right, there's other ways to make a living
• 40:22
  Speaker 10: that don't depend on light. And in fact, if we
• 40:25
  Speaker 10: if we look at those, those are things which are
• 40:27
  Speaker 10: probably pretty common in the universe as well. So you know,
• 40:30
  Speaker 10: the main way that metabolism works is by taking something
• 40:33
  Speaker 10: which is at a high energy state and reacting it
• 40:35
  Speaker 10: into a lower energy state and using the energy that's
• 40:38
  Speaker 10: released to power metabolism. These redox reactions are common. There's
• 40:42
  Speaker 10: many different ways to do it. A simple way is
• 40:44
  Speaker 10: to take hydrogen, right and sort of burn it into
• 40:47
  Speaker 10: with oxygen and burn it into water. That releases a
• 40:49
  Speaker 10: ton of energy and that can be used to power metabolism.
• 40:52
  Speaker 10: You may not have oxygen, I mean hydrogen that's really
• 40:55
  Speaker 10: common in the universe, so I think we can assume
• 40:57
  Speaker 10: that there may be some hydrogen around, right. You may
• 40:59
  Speaker 10: not have oxygen, however, I'm one of these planets. Although
• 41:03
  Speaker 10: I will say on a planet that has a surface water,
• 41:05
  Speaker 10: it's not that unlikely to think that there will be
• 41:07
  Speaker 10: some oxygen every now and then. And that's because if
• 41:09
  Speaker 10: there's light, light will take water it'll break it apart,
• 41:12
  Speaker 10: you know, ulti volt light will break it apart. The
• 41:14
  Speaker 10: hydrogen will escape into space, and you'll be left with oxygen,
• 41:17
  Speaker 10: which is persistence time depends on whether it reacts with things,
• 41:20
  Speaker 10: but you can have oxygen around.
• 41:22
  Speaker 1: So you're saying, we basically need liquid water, we need
• 41:24
  Speaker 1: some light, and we need some carbon and some hydrogen,
• 41:28
  Speaker 1: and then probably the microbes will be happy munching away
• 41:31
  Speaker 1: pretty much.
• 41:32
  Speaker 10: And it turns out that we can even make it
• 41:33
  Speaker 10: less restrictive than that. You can take light off the table,
• 41:36
  Speaker 10: although I think you know, since planet's usually around stars,
• 41:38
  Speaker 10: light's usually not off the table, but you could take
• 41:40
  Speaker 10: it off the table. And if you have hydrogen or
• 41:43
  Speaker 10: if you have iron, those are also very common, very
• 41:47
  Speaker 10: effective sources of generating the electron flow during a redox
• 41:51
  Speaker 10: reaction that can power life. So there's life on Earth
• 41:54
  Speaker 10: that can literally rust iron and grow using the energy
• 41:57
  Speaker 10: that comes from that. That same life can take carbon
• 42:01
  Speaker 10: dioxide and fix it, meaning turn it into longer chains
• 42:04
  Speaker 10: of carbon, and so you can basically if you have
• 42:07
  Speaker 10: carbon dioxide and you have iron, or if you have
• 42:10
  Speaker 10: hydrogen and carbon dioxide, you are good. If you have light,
• 42:14
  Speaker 10: you are really really good. And if you have oxygen, light, iron,
• 42:17
  Speaker 10: and carbon dioxide, it's chill. You can easily have lighted well.
• 42:21
  Speaker 1: As a physicist, I worry about other things, like levels
• 42:24
  Speaker 1: of radiation. You know, if this thing is getting like
• 42:27
  Speaker 1: impacted by huge numbers of cosmic rays, I worry about
• 42:30
  Speaker 1: them getting shredded. On the other hand, I have in
• 42:32
  Speaker 1: my head my wife's voice, and she's always telling me
• 42:35
  Speaker 1: that life survives everywhere. You know, they find it on
• 42:37
  Speaker 1: the outside of the Space shuttle and they find it.
• 42:40
  Speaker 1: You know, it's basically impossible to fully sterilize anything inside chernobyl.
• 42:45
  Speaker 1: You know, you find things that are rad hard. So
• 42:48
  Speaker 1: do we have to worry about these craters being fragile
• 42:50
  Speaker 1: or we're pretty sure if we have a big enough
• 42:52
  Speaker 1: sample that some of them are going to survive.
• 42:54
  Speaker 10: I think it's not a big worry. If you have
• 42:55
  Speaker 10: a large sample, you'll have things that survive. Plus you
• 42:58
  Speaker 10: could have them in habit environments that are protected. You know,
• 43:01
  Speaker 10: Hydrothermal events on the bottom of the ocean, for example,
• 43:04
  Speaker 10: will buffer you from a lot of stuff, and then
• 43:06
  Speaker 10: organisms can evolve mechanisms that make them much more robust
• 43:09
  Speaker 10: to the damage to DNA that's caused by high intensity
• 43:12
  Speaker 10: waves and particles. So you know, a lot of organisms
• 43:15
  Speaker 10: like tartar grades are often touted as a cool example
• 43:18
  Speaker 10: of something which is robust to DNA fragmentation.
• 43:21
  Speaker 1: They've evolved a lot of.
• 43:22
  Speaker 10: Cool mechanisms that can take DNA that's been busted into
• 43:26
  Speaker 10: a bunch of small pieces and reassembled in a pretty
• 43:29
  Speaker 10: accurate manner.
• 43:29
  Speaker 1: All right, So say you're tasked with developing this payload.
• 43:32
  Speaker 1: We're going to drop it on some random alien planet
• 43:35
  Speaker 1: you know very little about, just because you've seen maybe
• 43:37
  Speaker 1: some spectroscopy from its atmosphere. What cocktail do you recommend sending?
• 43:42
  Speaker 1: I mean, should we just scoop up a sample from
• 43:44
  Speaker 1: a local forest? But does it really matter if they're
• 43:46
  Speaker 1: all so hardy.
• 43:47
  Speaker 10: I think it does matter in that you know, a
• 43:49
  Speaker 10: local forest, the surface of a local forest is probably
• 43:53
  Speaker 10: a very different environment than what you're going to find there,
• 43:55
  Speaker 10: and it's an environment that is not wet.
• 43:59
  Speaker 2: Right.
• 44:00
  Speaker 10: I think we're going to have our best bet with
• 44:01
  Speaker 10: something which targets oceans, because oceans are large, oceans are
• 44:04
  Speaker 10: relatively stable, and if let's hope that this planet has
• 44:07
  Speaker 10: surface water that's liquid and within those oceans. I think
• 44:10
  Speaker 10: I would have a mixture of things which inhabit both
• 44:12
  Speaker 10: the surface and our phototrophic so things which can photosynthesize
• 44:16
  Speaker 10: using light, and things which inhabit like seafloor niches where
• 44:21
  Speaker 10: they can do chemical chemical autotrophy, where they would be
• 44:23
  Speaker 10: basically breaking down hydrogen using hydrogen sulfide as an electronic
• 44:27
  Speaker 10: acceptor doing things which allow them to make a living
• 44:30
  Speaker 10: that is completely independent from a light based ecosystem.
• 44:34
  Speaker 1: So then what do you expect we might get, Say
• 44:37
  Speaker 1: we drop this thing on an alien planet and we
• 44:38
  Speaker 1: come back in fifty million years, or our descendants eventually
• 44:42
  Speaker 1: make it out there on slow colony ships. Are we
• 44:45
  Speaker 1: going to end up with just like a frothing ocean
• 44:47
  Speaker 1: filled with microbes, or are we going to show up
• 44:49
  Speaker 1: and there's gonna be dinosaurs in redwoods, or you know,
• 44:51
  Speaker 1: some alien version of these things.
• 44:53
  Speaker 10: Fifty million years is pretty short in the scheme of things,
• 44:57
  Speaker 10: so I think you're looking more at a frothing ocean
• 44:59
  Speaker 10: filled with mic growth, although they may terraform the planet
• 45:02
  Speaker 10: in the sense of creating eno foxygen. You know, the
• 45:05
  Speaker 10: amount of oxygen that we have in our atmosphere twenty
• 45:07
  Speaker 10: percent of our atmosphere that's all coming from life, right,
• 45:10
  Speaker 10: that's all coming from photosynthetic organisms. And so if this
• 45:14
  Speaker 10: planet doesn't have life already, if it's a steroplanet, there
• 45:17
  Speaker 10: won't be much, if any, oxygen available, Like the amount
• 45:20
  Speaker 10: of oxygen that we have is because of life. And
• 45:22
  Speaker 10: so I think if we could get you know, very
• 45:25
  Speaker 10: photosynthetically active ocean microbes. It might take a little longer
• 45:29
  Speaker 10: than fifty million years, but you could terraform the planet
• 45:31
  Speaker 10: in a way that would probably result in more of
• 45:33
  Speaker 10: an aerobic atmosphere, something which we're more happy with. But
• 45:36
  Speaker 10: to get something like dinosaurs and redwood trees and stuff,
• 45:39
  Speaker 10: I would probably actually jump the gun a little bit
• 45:41
  Speaker 10: here and see the world with more highly, more derived
• 45:45
  Speaker 10: organisms than just these bacteria which are hardy, which can live.
• 45:49
  Speaker 10: You know, bacteria are like the ultimate metabolic you know,
• 45:53
  Speaker 10: tool kit masters. If there is an energy source to
• 45:55
  Speaker 10: be dissipated, there's a bacteria or an archea, a single
• 45:58
  Speaker 10: cell organism that that has evolved to dissipate that. You know,
• 46:01
  Speaker 10: there's bacteria living miles deep in rocks eating only hydrogen. Amazing,
• 46:08
  Speaker 10: it's outstand You know, they might divide once every thousand years.
• 46:11
  Speaker 10: It's it's really cool. But these types of more complex organisms,
• 46:14
  Speaker 10: generally speaking, these multicellular organisms that we can see that
• 46:17
  Speaker 10: have you know, complex morphological features, they evolve from eukaryotes,
• 46:22
  Speaker 10: which are a different kind of organism that's actually the
• 46:25
  Speaker 10: result of a symbiosis between a bacterial cell and an
• 46:28
  Speaker 10: archel cell, and that symbiosis started on the order of
• 46:32
  Speaker 10: two billion years ago. And these organisms have compared to bacteria,
• 46:36
  Speaker 10: they have a lot more complicated subcellular features. They have
• 46:40
  Speaker 10: their DNA incased within a nucleus, they have more complicated
• 46:44
  Speaker 10: mechanisms for generating and moving proteins, and they have many
• 46:47
  Speaker 10: more opportunities for within cell gene regulation. And it's within
• 46:53
  Speaker 10: this more complicated kind of cell that you've gotten the
• 46:55
  Speaker 10: types of multicecular organisms that we know and love. Plants,
• 46:59
  Speaker 10: animal fungi, dinosaurs, redwood trees, and in fact, even those
• 47:04
  Speaker 10: lineages which have evolved pretty sophisticated forms of multicellularity, it
• 47:08
  Speaker 10: took them quite a while to do that. So animals
• 47:10
  Speaker 10: have been around for you know, on the order of
• 47:12
  Speaker 10: at least six hundred million years. Plants cropped up around
• 47:16
  Speaker 10: four hundred and twenty million years ago is kind of
• 47:18
  Speaker 10: when they got their start. Fungi have probably been around
• 47:20
  Speaker 10: for about a billion years, although it's hard to tell
• 47:23
  Speaker 10: when they became multicecular, but it often actually took quite
• 47:26
  Speaker 10: a while for this origin of.
• 47:27
  Speaker 1: Multicecularity play out.
• 47:29
  Speaker 10: But I will say, once you give them a toolkit
• 47:32
  Speaker 10: where they have the ability to have cells that remain
• 47:35
  Speaker 10: attached to one another and to specialize in different behaviors,
• 47:38
  Speaker 10: and you know, regulate that specialization through communication or other
• 47:42
  Speaker 10: bioelectric sensing in response mechanisms. Once they have those toolkits
• 47:47
  Speaker 10: for how cells grow into bodies and specialize and undergo
• 47:51
  Speaker 10: morphological novel morphological function, they can diversify very quickly from
• 47:56
  Speaker 10: that starting point. So I think what you'd want to
• 47:59
  Speaker 10: do is like see that world with maybe relatively hardy,
• 48:02
  Speaker 10: relatively simple plants, animals, and fungi, and then let those
• 48:06
  Speaker 10: things diversify into the various psychological niches that they find,
• 48:09
  Speaker 10: although you might actually have to do a sequential now
• 48:11
  Speaker 10: that I think about this sequential seating, hit them with
• 48:14
  Speaker 10: the basic stuff to get you know, a carbon rich
• 48:16
  Speaker 10: ecosystem going, and then toss in the more complicated stuff.
• 48:20
  Speaker 10: You know, a couple thousand years later.
• 48:23
  Speaker 1: So what do you think is the most complex form
• 48:25
  Speaker 1: of life that might survive this kind of trip. I'm
• 48:27
  Speaker 1: imagining this thing is like frozen or desiccated and then
• 48:30
  Speaker 1: dropped in the ocean with basically nothing, and we hope
• 48:33
  Speaker 1: it just sort of reconstitutes itself. You can't do that
• 48:35
  Speaker 1: with like a dog, right or a tree. So are
• 48:38
  Speaker 1: we seeding this planet with tartar grades to come back
• 48:41
  Speaker 1: fifty million years later to find human size intelligent tartar grades?
• 48:44
  Speaker 10: Oh, that's a fantastic question. So freezing things for interstellar travel,
• 48:49
  Speaker 10: like a lot of smaller organisms, there's probably a way
• 48:51
  Speaker 10: to work that part out of that too much difficulty.
• 48:54
  Speaker 10: You can freeze, you know, you can't freeze a fly,
• 48:56
  Speaker 10: but you can freeze you know, a number of smaller animals.
• 48:59
  Speaker 10: Certainly tartar grades would have no problem being desiccated and
• 49:02
  Speaker 10: shipped around the around the universe. But I don't think
• 49:04
  Speaker 10: that they're going to become you know, large and complicated.
• 49:06
  Speaker 10: They make their living basically sucking up bacteria plants. I
• 49:10
  Speaker 10: think I would take advantage of resting stages explores, inferns
• 49:15
  Speaker 10: or or you know, heart very very durable seeds of angiosperms.
• 49:19
  Speaker 10: That being said, I don't know what, if anything, could
• 49:22
  Speaker 10: survive these extremely sterile conditions that we would find ourselves
• 49:25
  Speaker 10: with on a new planet. I mean, I think I
• 49:27
  Speaker 10: think bacteria are really like they should do fine. You know,
• 49:31
  Speaker 10: if you throw enough stuff, enough different types of bacteria,
• 49:34
  Speaker 10: with enough different forms of metabolism at a blank slate
• 49:37
  Speaker 10: environment where there are energetic you know, conditions, energetic equilibria
• 49:42
  Speaker 10: to be dis equilibria to sort of be taken advantage
• 49:44
  Speaker 10: of and be used for energy, you're going to get
• 49:46
  Speaker 10: something which grows on that. But plants, animals, fungi, those
• 49:49
  Speaker 10: are all things which largely have evolved in the context
• 49:52
  Speaker 10: of an already pretty rich ecosystem of other organisms, and
• 49:55
  Speaker 10: they're highly dependent on those other organisms to make their living.
• 49:58
  Speaker 10: I mean, plants you might be able to get away
• 50:00
  Speaker 10: with in the sense that they are mostly self sustaining
• 50:03
  Speaker 10: photo autotrophic organisms that are growing on light, water and minerals.
• 50:08
  Speaker 10: But even plants are really specialized on growing on land
• 50:12
  Speaker 10: like plants are basically you know, we talked about, oh,
• 50:14
  Speaker 10: the invasion of land. Really it's the invasion of air
• 50:17
  Speaker 10: from a marine algae that was the difficult part for plants.
• 50:20
  Speaker 10: So I think you could probably if I was gonna
• 50:22
  Speaker 10: throw anything in there that was that was larger and
• 50:24
  Speaker 10: more complicated, it would be something like a seaweed, right,
• 50:27
  Speaker 10: because they're they're phototrophic, They're they're getting their energy from
• 50:30
  Speaker 10: the from the sun and minerals. There are many mutualistic
• 50:35
  Speaker 10: interactions that they have with other organisms. But I'm sure
• 50:37
  Speaker 10: you could find something which doesn't depend on those and
• 50:39
  Speaker 10: can grow azenically. And then once you have macro algae growing,
• 50:44
  Speaker 10: they create a habitat for many different organisms, lots of animals,
• 50:48
  Speaker 10: for example. So if I thought about this more, maybe
• 50:51
  Speaker 10: what you know, what I would do. I'm not sure
• 50:52
  Speaker 10: how you would ship this around the universe, But have
• 50:54
  Speaker 10: you ever seen those fully enclosed little ecosystems that have
• 50:58
  Speaker 10: some algae and some shrimp. I think they're Hawaiian and
• 51:01
  Speaker 10: they can live like in a completely enclosed, sealed glass
• 51:04
  Speaker 10: sphere for decades where that you know, basically you have
• 51:06
  Speaker 10: this nice balance between the oxygen that's produced by the
• 51:10
  Speaker 10: algae and the food that's created and the shrimp which
• 51:12
  Speaker 10: consume it and create carbon dioxide which the algae use.
• 51:15
  Speaker 10: It's pretty cool. So something like that maybe some small
• 51:18
  Speaker 10: invertebrate which is mostly grazier on algae or even eatings.
• 51:23
  Speaker 10: Think that might the single sid alogae which grow on
• 51:26
  Speaker 10: the surface of macrology and macrology and maybe try to
• 51:29
  Speaker 10: get that established. I don't know about just throwing it
• 51:31
  Speaker 10: into a sterilotionan, but if there was a way to
• 51:34
  Speaker 10: sort of, you know, have an incubator where you have
• 51:37
  Speaker 10: a near shore environment or a pond something a little
• 51:40
  Speaker 10: bit less big then subject to planetary scale weather.
• 51:48
  Speaker 1: So is this an idea which excites you? You're like, ooh,
• 51:51
  Speaker 1: this would be really fun to see what happens. Or
• 51:53
  Speaker 1: is something that terrifies you the idea of you know,
• 51:55
  Speaker 1: polluting the galaxy with our kind of life. You know,
• 51:58
  Speaker 1: is it wonderful to imagine show up on this planet
• 52:01
  Speaker 1: and having like intelligent shrimp swimming in kelp forests that
• 52:04
  Speaker 1: we seeded, you know, long times ago.
• 52:08
  Speaker 10: It's more exciting than terrifying for the simple reason that,
• 52:11
  Speaker 10: while we don't really know what the extent of independently
• 52:15
  Speaker 10: evolved the life on other planets is, it seems like
• 52:18
  Speaker 10: the amount of planets that exist vastly as strips the
• 52:21
  Speaker 10: amount of independent origins of life certainly complex life, and
• 52:26
  Speaker 10: so it doesn't seem to me that planets with liquid
• 52:30
  Speaker 10: water are necessarily a super limiting resource in our universe.
• 52:33
  Speaker 10: And so the opportunity to see how life would evolve
• 52:37
  Speaker 10: given replays of the tape, right to see how it
• 52:40
  Speaker 10: would independently go about colonizing a planet diversifying, I mean
• 52:43
  Speaker 10: you could. It would be It's a once in a
• 52:46
  Speaker 10: lifetime opportunity to see how something which starts over reconstitutes itself,
• 52:51
  Speaker 10: how a bioswear reconstitutes itself.
• 52:52
  Speaker 1: So you want to turn the entire galaxy into your
• 52:54
  Speaker 1: own lab.
• 52:55
  Speaker 11: Basically, I mean, you know, I wouldn't say no, that's
• 52:58
  Speaker 11: the exciting part, but I would say you'd have to
• 53:01
  Speaker 11: be very, very confident that there wasn't already existing life
• 53:04
  Speaker 11: on that planet before you went about doing this.
• 53:07
  Speaker 10: I mean, if it truly was sterile, then I don't
• 53:08
  Speaker 10: think that there's a huge amount of downside, But a
• 53:11
  Speaker 10: lot of that depends on how confident you are that
• 53:12
  Speaker 10: it really is a sterile planet. And you know that
• 53:14
  Speaker 10: being said, if this planet's sterile, and it's been sterile
• 53:17
  Speaker 10: presumably for quite a long time, despite being habitable billions
• 53:22
  Speaker 10: of years, it seems unlikely that it would all of
• 53:24
  Speaker 10: a sudden not become sterile in the near future anyway,
• 53:27
  Speaker 10: So I don't know what you're giving up.
• 53:28
  Speaker 1: All right, Well, thanks very much for sharing your excitement
• 53:31
  Speaker 1: and your insights with us. Really appreciate your time. It's
• 53:34
  Speaker 1: a pleasure. And of course I checked in with Katrina
• 53:37
  Speaker 1: and to see how much she agreed with Will. So then,
• 53:40
  Speaker 1: if microbes are so hardy, if we wanted to seed
• 53:42
  Speaker 1: an exo planet with life, could we just send anything
• 53:45
  Speaker 1: we want or do they need to be carefully chosen?
• 53:48
  Speaker 4: I think diversity would be a better strategy than like
• 53:52
  Speaker 4: carefully choosing just one strategy, So I think you would
• 53:55
  Speaker 4: be better off. You'd be more likely to succeed by
• 53:58
  Speaker 4: gathering up microbes from a lot of different environments and
• 54:01
  Speaker 4: then sending as many different strategies out there, so you'd
• 54:05
  Speaker 4: get to roll the.
• 54:06
  Speaker 3: Dice a lot more times.
• 54:07
  Speaker 4: But I think you would want to pick from environments
• 54:09
  Speaker 4: that are already harsh and potentially similar to the place
• 54:12
  Speaker 4: that you're trying to bring the microbes to, so that
• 54:15
  Speaker 4: they would already be adapted.
• 54:16
  Speaker 3: But yeah, if I had to pick.
• 54:18
  Speaker 4: Between, like, you know, one lab evolving a perfect bug
• 54:22
  Speaker 4: versus just like sampling all of Earth's environments.
• 54:25
  Speaker 3: I would vote Earth's environments.
• 54:27
  Speaker 1: So I think Will's answer your question is that would
• 54:30
  Speaker 1: take a lot longer than fifty million years to get
• 54:32
  Speaker 1: from microbes to redwoods and dinosaurs and grocery stores.
• 54:37
  Speaker 2: So I am not going to be shopping at the
• 54:38
  Speaker 2: brown dwarf grocery store.
• 54:41
  Speaker 1: That's a bum no. But you are great gree kirkirk kirkkrekerk.
• 54:46
  Speaker 1: Great grandkids might be able to have dinosaur steaks for dinner.
• 54:49
  Speaker 2: Thank goodness, the future is good. Okay, So, as you
• 54:55
  Speaker 2: may have been able to pick up throughout the course
• 54:57
  Speaker 2: of the conversation, I have some concern about this idea,
• 55:01
  Speaker 2: though I do find it interesting. So should we do it?
• 55:05
  Speaker 2: Let's end on that. So how about in our solar system?
• 55:08
  Speaker 2: What do you think should we ever do this?
• 55:10
  Speaker 1: I think it's a hard question in general, but I
• 55:12
  Speaker 1: think that in our solar system it's pretty clear, Like, yes,
• 55:15
  Speaker 1: it'd be nice to be able to live on Gainy
• 55:18
  Speaker 1: Meede or on Io. But if we just send our
• 55:21
  Speaker 1: microbes and spray them all over the solar system in
• 55:23
  Speaker 1: the hopes of eventually having a biome that could support us,
• 55:26
  Speaker 1: we're ruining our chance to answer a much deeper, more
• 55:29
  Speaker 1: important question, right, like how hard is it for life
• 55:32
  Speaker 1: to start? Could life have started in other places in
• 55:35
  Speaker 1: the Solar system independently, or maybe life in the Solar
• 55:39
  Speaker 1: system actually did start only one place, but not on Earth,
• 55:42
  Speaker 1: and then came to Earth. If we sprayed bacteria microbes
• 55:46
  Speaker 1: all over our Solar system, we couldn't answer these questions.
• 55:49
  Speaker 1: We'll have polluted our backyard. And I think those questions
• 55:52
  Speaker 1: are more important than grocery stores on io.
• 55:56
  Speaker 2: I think many people would disagree with you, especially when
• 55:59
  Speaker 2: it comes to Mars, because, of course, if we're going
• 56:01
  Speaker 2: to settle Mars, we are going to be seeding Mars
• 56:03
  Speaker 2: with all kinds of stuff, and depending on how soon
• 56:06
  Speaker 2: we do that, that might be before we even know
• 56:09
  Speaker 2: for sure if Mars has life on it or not.
• 56:12
  Speaker 2: So this is, you know, something that could possibly happen
• 56:15
  Speaker 2: in our lifetime. But do you think that the ethical
• 56:19
  Speaker 2: questions become or have a little clearer answers if we're
• 56:22
  Speaker 2: talking about other solar systems.
• 56:24
  Speaker 1: Well, I want to get back to Mars actually, because
• 56:26
  Speaker 1: as a world famed skeptic on the possibility of settling Mars,
• 56:30
  Speaker 1: I have to ask you do you think it's possible
• 56:33
  Speaker 1: to settle Mars and not pollute it, Like, could we
• 56:36
  Speaker 1: set up some sort of barrier where we have like
• 56:38
  Speaker 1: an Earth region on Mars and somehow avoid contaminating the
• 56:43
  Speaker 1: rest of the planet or is that impossible.
• 56:46
  Speaker 2: I'm not very optimistic that we could do that. So
• 56:48
  Speaker 2: you know, Mars has dust worms that blow dust all
• 56:51
  Speaker 2: over the planet, and you know, I think there are
• 56:53
  Speaker 2: microbes that you know, even if you said like okay,
• 56:55
  Speaker 2: no humans are allowed to, you know, cross this line
• 56:58
  Speaker 2: and half the planet is going to be pristine, I
• 57:00
  Speaker 2: think our microbes over time would sort of blow around
• 57:02
  Speaker 2: the planet. And you know, if there's no microbes there
• 57:06
  Speaker 2: then they're already then maybe that's not so bad, although
• 57:10
  Speaker 2: the microbes will start changing, you know, like the chemistry
• 57:13
  Speaker 2: of the environment, and that might make some scientists sad
• 57:15
  Speaker 2: who wanted to study Mars and it's like preserved states.
• 57:18
  Speaker 2: So you know, there's a lot of trade offs you
• 57:21
  Speaker 2: need to make when you're thinking about what to do
• 57:22
  Speaker 2: with another planet.
• 57:24
  Speaker 1: Yeah, it really does seem like we have to decide
• 57:26
  Speaker 1: is Mars a scientific preserve or is it a resource
• 57:30
  Speaker 1: to be exploited.
• 57:32
  Speaker 2: Yeah, and then the difficult thing is, you know, if
• 57:33
  Speaker 2: the US decides one thing, or in China decides another,
• 57:37
  Speaker 2: or Russia decides another, Like, can you get the whole
• 57:40
  Speaker 2: global community to agree on what we're going to use
• 57:43
  Speaker 2: Mars for? And I guess we'll see.
• 57:45
  Speaker 1: Yeah, And not just governments, right, eccentric zillionaires can start
• 57:48
  Speaker 1: their own Mars colony outside of any jurisdiction. Right, there
• 57:52
  Speaker 1: are no laws on Mars as far as I'm aware.
• 57:54
  Speaker 2: No, no, nope, nop nope. So if Musk wanted to
• 57:57
  Speaker 2: go to Mars, he would still have to like at
• 58:00
  Speaker 2: a permit through the FAA, and he would have to
• 58:03
  Speaker 2: like essentially get approval from the US government. And when
• 58:07
  Speaker 2: you're out in space, you are still the responsibility of
• 58:09
  Speaker 2: some government. So Musk would still be the United States' responsibility.
• 58:14
  Speaker 2: They should be telling him what he can or cannot
• 58:16
  Speaker 2: do out there. So you know, the Outer Space Treaty
• 58:20
  Speaker 2: is international law that is supposed to apply to when
• 58:23
  Speaker 2: humans go out into space as well. But you know,
• 58:26
  Speaker 2: is Musk gonna listen? That's a different question entirely. And
• 58:30
  Speaker 2: what would be the implications if he doesn't listen? Who knows?
• 58:33
  Speaker 2: Because the US could say no more.
• 58:35
  Speaker 1: You're gonna throw him in Mars jail.
• 58:36
  Speaker 2: That's right. I mean, so the US does have some leverage.
• 58:39
  Speaker 2: They could say we're not sending any more resupply ships
• 58:42
  Speaker 2: until you guys, you know, get your axe cleaned up.
• 58:44
  Speaker 2: But yeah, who knows what muscle will do when he
• 58:47
  Speaker 2: gets there.
• 58:47
  Speaker 1: Yeah, so it's a tricky question here in our solar system.
• 58:50
  Speaker 1: In terms of other solar systems, I think it's related,
• 58:52
  Speaker 1: But for me, the balance tips a little bit in
• 58:54
  Speaker 1: the other direction. Like, there are so many planets out there,
• 58:57
  Speaker 1: I'm fairly confident we could find some that have no
• 59:00
  Speaker 1: life on them that we could use as experiments or
• 59:03
  Speaker 1: we could use to seed edible biomes for the very
• 59:06
  Speaker 1: future of humanity. Seems to me to be too restrictive
• 59:10
  Speaker 1: to say we can't explore or we can't experiment anywhere
• 59:13
  Speaker 1: in the galaxy.
• 59:14
  Speaker 8: Yeah.
• 59:14
  Speaker 2: I think if you could absolutely convince me that we
• 59:19
  Speaker 2: definitely knew what to look for and could absolutely determine
• 59:22
  Speaker 2: that a planet was sterile, you know, the evolutionary biologist
• 59:26
  Speaker 2: and me would love to see what happens if you,
• 59:28
  Speaker 2: you know, drop microbes and then come back, you know,
• 59:30
  Speaker 2: six billion years later, what do you have there that
• 59:33
  Speaker 2: sounds fascinating. It would be difficult for you to convince
• 59:36
  Speaker 2: me that it was definitely a sterile planet and we
• 59:38
  Speaker 2: weren't going to be, especially when it's you know, in
• 59:40
  Speaker 2: a different solar system. But if you could convince me
• 59:42
  Speaker 2: of that, then I would certainly be interested in seeing
• 59:44
  Speaker 2: this experiment run, not just because I love food so much,
• 59:47
  Speaker 2: but because I think there'd be interesting science.
• 59:49
  Speaker 1: Yeah, because it would be a huge tragedy if there
• 59:52
  Speaker 1: really was like alien life on that planet and then
• 59:54
  Speaker 1: we sent our microbes and it like wiped them out.
• 59:57
  Speaker 1: What if we showed up and there were like fossils
• 59:59
  Speaker 1: of a dead civilation that we had killed with our
• 1:00:02
  Speaker 1: equivalent of smallpox.
• 1:00:03
  Speaker 2: Oh, that would be awful. And also from like a
• 1:00:06
  Speaker 2: science perspective, like losing all of the data on like
• 1:00:09
  Speaker 2: when life actually pops up independently and the direction that
• 1:00:13
  Speaker 2: that took, as opposed to you know, what does our
• 1:00:15
  Speaker 2: life when you put it somewhere else. I think it's
• 1:00:17
  Speaker 2: much more interesting to see what happens when life pops
• 1:00:20
  Speaker 2: up somewhere else on its own, and then what happens
• 1:00:22
  Speaker 2: to it. But yeah, so many levels of it being
• 1:00:24
  Speaker 2: super sad if it turns out we're messing up what's
• 1:00:27
  Speaker 2: happening on some other planet.
• 1:00:28
  Speaker 9: Yeah.
• 1:00:29
  Speaker 1: If that happens, we should get thrown in space jail.
• 1:00:31
  Speaker 2: Yes, yeah, except you know we will have long since
• 1:00:35
  Speaker 2: been dead because it will take so long to get
• 1:00:37
  Speaker 2: the microbes there. So I guess our whole species would
• 1:00:40
  Speaker 2: have to get thrown into space jail.
• 1:00:42
  Speaker 1: Yeah, exactly. I think it's an interesting question even if
• 1:00:45
  Speaker 1: we never do it, right, even if we don't actually
• 1:00:47
  Speaker 1: do this, it's fun to imagine, like, how would it work?
• 1:00:51
  Speaker 1: What technology would you need? Is it even possible? To me,
• 1:00:54
  Speaker 1: it's fascinating that we're not actually that far from this
• 1:00:57
  Speaker 1: kind of technology, like solar sales. We could build that
• 1:01:00
  Speaker 1: and that it breaks. Probably that would work. Capsules of
• 1:01:02
  Speaker 1: ocean water which might survive the transit from here to there.
• 1:01:06
  Speaker 1: That's not implausible, Like this sort of science fictiony scenario
• 1:01:10
  Speaker 1: could be reality in the not far future.
• 1:01:13
  Speaker 2: Yeah. We live in exciting times with exciting possibilities. I
• 1:01:15
  Speaker 2: hope we make the right choices.
• 1:01:17
  Speaker 1: Since we're talking about some big moral choices. I asked
• 1:01:20
  Speaker 1: Katrina about the should we side of this question, and
• 1:01:24
  Speaker 1: how would you feel if an alien payload arrived with
• 1:01:27
  Speaker 1: their microbes hoping to seed our world with their bugs.
• 1:01:31
  Speaker 1: Would you feel invaded or intrigued?
• 1:01:35
  Speaker 4: I mean, obviously intrigued, but how would I handle.
• 1:01:39
  Speaker 1: I hope you're listening to that aliens.
• 1:01:42
  Speaker 3: Yeah, and CDC. I hope the CDC is not listening
• 1:01:46
  Speaker 3: to that one too much. Actually.
• 1:01:48
  Speaker 4: I mean, you would definitely want to do that kind
• 1:01:50
  Speaker 4: of work in a very careful environment, and we do
• 1:01:53
  Speaker 4: know how to work with pathogens. It's never perfect, though,
• 1:01:56
  Speaker 4: I mean, that's a whole other conversation. But you know,
• 1:01:58
  Speaker 4: I don't love hearing them there's small pox in a
• 1:02:02
  Speaker 4: freezer somewhere, and it's just one mistake away from getting
• 1:02:06
  Speaker 4: into contact with humanity again. And so not knowing what
• 1:02:09
  Speaker 4: the health impact or the environmental climate impact of a
• 1:02:13
  Speaker 4: new set of microbes would be, I would definitely want
• 1:02:16
  Speaker 4: to tread lightly, but I'd be super intrigued. Oh my gosh,
• 1:02:19
  Speaker 4: that's a dream to get to figure out how on Earth,
• 1:02:23
  Speaker 4: how on wherever they came from they do their metabolisms
• 1:02:27
  Speaker 4: and copy themselves, and I mean that would be fascinating.
• 1:02:32
  Speaker 1: I hope you feel like you've made the right choice
• 1:02:33
  Speaker 1: in listening to me and Kelly talk about this question
• 1:02:36
  Speaker 1: for the last hour, and I hope that you learned something,
• 1:02:39
  Speaker 1: not just about whether or not Kelly is likely to
• 1:02:41
  Speaker 1: chop you up, but whether future humanity could and should
• 1:02:45
  Speaker 1: send microbes to other planets.
• 1:02:48
  Speaker 2: I was the scary co host this time. Usually that's your.
• 1:02:50
  Speaker 1: Job exactly now. I know what it feels like. Oh
• 1:02:55
  Speaker 1: my gosh, I'm quivering my boots, and I'm glad we're
• 1:02:57
  Speaker 1: across the country from each Others very much for joining us,
• 1:03:00
  Speaker 1: even though you threatened to slice me into pieces.
• 1:03:03
  Speaker 2: Thanks very much for having me, for being a good
• 1:03:06
  Speaker 2: sport when the tables returned.
• 1:03:10
  Speaker 1: All right, Thanks for listening. Everyone, tune in next time.
• 1:03:21
  Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain
• 1:03:24
  Speaker 1: the Universe is a production of iHeartRadio. For more podcasts
• 1:03:28
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• 1:03:33
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