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Can humans survive interstellar travel? · Daniel and Kelly’s Extraordinary Universe

• 0:05
  Speaker 1: Imagine a future one hundred maybe two hundred years from now.
• 0:10
  Speaker 1: In space, manufacturing has come a long way, and we
• 0:13
  Speaker 1: can now build colossal structures using resources collected from the
• 0:17
  Speaker 1: Moon and the asteroids. First interstellar ship has been built
• 0:22
  Speaker 1: and is getting loaded up with supplies for a long
• 0:24
  Speaker 1: trip to Alpha Centauri. It's now time to pick the
• 0:27
  Speaker 1: crew who will be the ambassadors for humanity should we
• 0:30
  Speaker 1: meet intelligent life in the neighboring Solar System. How many
• 0:34
  Speaker 1: people will we send, how should we pick them, What
• 0:37
  Speaker 1: dangers will they face en root and what will their
• 0:39
  Speaker 1: lives be like during this journey. In our last episode,
• 0:43
  Speaker 1: we talked about the rockets that could carry us to
• 0:46
  Speaker 1: distant stars. Today, we're going to talk about the squishier
• 0:49
  Speaker 1: side of things, focusing on some of the human stuff
• 0:52
  Speaker 1: you'd have to deal with on an interstellar journey. Welcome
• 0:55
  Speaker 1: to Daniel and Kelly's Extraordinary Universe. Hi.
• 1:12
  Speaker 2: I'm Daniel. I'm a particle physicist and the longest flight
• 1:15
  Speaker 2: I've ever taken was fourteen hours.
• 1:18
  Speaker 1: Hi. I'm Kelly Wiiner Smith. I studied parasites in space,
• 1:22
  Speaker 1: and I think the longest flight I've taken was twelve
• 1:24
  Speaker 1: I've been down to Brazil. I haven't really kept track
• 1:27
  Speaker 1: of how long my flights were. Where were you going?
• 1:29
  Speaker 2: I went to an absolutely ridiculous slash amazing boondoggle conference
• 1:33
  Speaker 2: in Fiji on the island of Morea, where the University
• 1:37
  Speaker 2: of California has a research station, and we were there
• 1:39
  Speaker 2: to talk about dark matter, of course, So I brought
• 1:43
  Speaker 2: my daughter and we did a lot of snorkeling and hiking,
• 1:46
  Speaker 2: and we rode horseback of the mountains and tried to
• 1:49
  Speaker 2: keep the horses from eating pineapple plants. And it was
• 1:51
  Speaker 2: an amazing time. But wow, the flight was long.
• 1:54
  Speaker 1: What made it a boondoggle?
• 1:56
  Speaker 2: Why do you need to go to a tropical island
• 1:58
  Speaker 2: to talk about dark matter?
• 2:00
  Speaker 1: Don't That's what makes it a Yeah, I gotta be honest.
• 2:04
  Speaker 1: Ecology has a lot of that too. It's like, why
• 2:06
  Speaker 1: do you need to go to the glorious rainforest to
• 2:09
  Speaker 1: answer questions about frogs when you've got frogs in the US.
• 2:12
  Speaker 1: But I get it. We like go into beautiful places.
• 2:14
  Speaker 2: Yeah, it's one of the perks of being a scientist
• 2:16
  Speaker 2: is getting to travel to weird, random places to meet
• 2:19
  Speaker 2: with your colleagues.
• 2:21
  Speaker 1: That's true, that's true. I love getting to see new places.
• 2:23
  Speaker 1: I often get invited to places that I never actually
• 2:26
  Speaker 1: really wanted to go to, but once I get invited,
• 2:28
  Speaker 1: I'm like, yeah, I want to go to Slovakia, and
• 2:31
  Speaker 1: I love Slovakia. Broadoslava was beautiful.
• 2:34
  Speaker 2: Well what's your experience like on these long flights, because
• 2:36
  Speaker 2: I always feel like, oh, fourteen hours, no big deal.
• 2:39
  Speaker 2: I'll just watch a few movies and then like two
• 2:41
  Speaker 2: movies in, I'm like, wow, get me off this plane,
• 2:44
  Speaker 2: and then like four movies in I'm gonna kill myself.
• 2:47
  Speaker 2: And then by the time I land, I'm like, hmm,
• 2:49
  Speaker 2: that wasn't so bad.
• 2:52
  Speaker 1: I hate it. I have a very similar experience. I
• 2:54
  Speaker 1: can't sleep. I try to sleep, I can't sleep. I'm
• 2:56
  Speaker 1: not comfortable. Every once in a while, I'll get lucky
• 2:59
  Speaker 1: and there'll be no one else in the row and
• 3:00
  Speaker 1: I can just like lay down and at least then
• 3:03
  Speaker 1: I feel kind of rest ish or restoids. I know,
• 3:09
  Speaker 1: I hate it too, And then I always feel kind
• 3:12
  Speaker 1: of angry at the people in first class because they've
• 3:14
  Speaker 1: got like a much nicer setup. But you know, what
• 3:18
  Speaker 1: are you gonna do.
• 3:18
  Speaker 2: You're not gonna spend ten thousand dollars for that flight,
• 3:21
  Speaker 2: that's right. Yeah, no, But if I was an astronaut
• 3:25
  Speaker 2: and I was going to the Moon or to Mars
• 3:27
  Speaker 2: or to Alpha Centauri, I might want the engineers to
• 3:31
  Speaker 2: build in a seat that can fully recline. What do
• 3:33
  Speaker 2: you think?
• 3:33
  Speaker 1: Heck, yes, you do have to have a completely different
• 3:36
  Speaker 1: mindset to really enjoy super long trips. Like Jim Lovell
• 3:40
  Speaker 1: and Frank Borman were on a Gemini trip around the
• 3:43
  Speaker 1: Earth and I think they were up there for something
• 3:45
  Speaker 1: like two weeks, and it was a really tiny space
• 3:47
  Speaker 1: and at least on airplanes, like, yeah, the bathroom is small,
• 3:49
  Speaker 1: it's super inconvenient. I hate it. But it's got a
• 3:52
  Speaker 1: door and the Gemini didn't. And so Frank Borman tried
• 3:57
  Speaker 1: to go all twelve days without having a bowel movement,
• 4:00
  Speaker 1: and I think he made it like eight days or something,
• 4:02
  Speaker 1: and then he was like, Jim, I can't wait anymore.
• 4:06
  Speaker 2: I'm about to make a delivery.
• 4:07
  Speaker 1: Oh gosh. Yeah, So anyway, it could be worse.
• 4:10
  Speaker 2: So you're saying that the cutting edge super distant travel
• 4:13
  Speaker 2: is less convenient and less comfortable than like economy flights
• 4:17
  Speaker 2: across the country. That doesn't make any sense to me.
• 4:19
  Speaker 1: Well, you know, you've got to pay for all of
• 4:21
  Speaker 1: the space that you send up there, and it's super expensive.
• 4:24
  Speaker 1: And I mean, let's be honest, anybody who's told you
• 4:26
  Speaker 1: get to go to space is going to put up
• 4:27
  Speaker 1: with whatever you give them, and so they're definitely going
• 4:30
  Speaker 1: to go. But there was a recent SpaceX trip where
• 4:32
  Speaker 1: there were complaints about the bathroom also, and I think
• 4:35
  Speaker 1: it was the Dragon capsule. Restrooms in space are just
• 4:37
  Speaker 1: hard to pull off.
• 4:38
  Speaker 2: Well, I think this is another case of like my
• 4:41
  Speaker 2: over optimistic rose colored glasses when it comes to space travel,
• 4:44
  Speaker 2: imagining that the problems we have with like airplane flights
• 4:47
  Speaker 2: are not going to be even worse on space trips.
• 4:50
  Speaker 2: They're somehow all going to be comfortable and get along
• 4:53
  Speaker 2: and the food is going to be amazing like it
• 4:55
  Speaker 2: is on Star Trek. Right. That's why I was excited
• 4:58
  Speaker 2: that today we're going to dig into like the reality
• 5:00
  Speaker 2: of a potential interstellar trip. What's it going to be like?
• 5:03
  Speaker 2: Will there be doors on the bathrooms? How far back
• 5:05
  Speaker 2: will this eat recline? And will they have anything besides
• 5:08
  Speaker 2: peanuts and pretzels?
• 5:10
  Speaker 1: Well, let's dig in and find out. So this is
• 5:12
  Speaker 1: part two of our interstellar travel series. We talked about
• 5:16
  Speaker 1: the kinds of rockets that get you to space in
• 5:18
  Speaker 1: the last episode, and today we're talking about the squishy
• 5:20
  Speaker 1: human side of things, and so we asked our listeners,
• 5:24
  Speaker 1: can humans survive interstellar travel? Why or why not. Here's
• 5:29
  Speaker 1: what they had to say. Humans could survive interstellar travel
• 5:33
  Speaker 1: with terraform spaceships, and over multiple generations, they could get
• 5:39
  Speaker 1: somewhere interesting.
• 5:40
  Speaker 3: There are so many unknown issues with closed ecosystems in
• 5:46
  Speaker 3: order to produce the food that we need in the
• 5:50
  Speaker 3: form of plants, et cetera, that I'm too sure that
• 5:53
  Speaker 3: we've solved all the problems necessary in order to have
• 5:55
  Speaker 3: a long duration interstellar travel with.
• 5:58
  Speaker 4: Our current technology. I don't think it's possible, but maybe
• 6:02
  Speaker 4: with advances in propulsion and radiation shielding and artificial gravity
• 6:09
  Speaker 4: from propulsion, that might be possible.
• 6:11
  Speaker 5: One human couldn't survive because we haven't sought in suspended
• 6:15
  Speaker 5: animation yet. But if you're talking about generations of humans,
• 6:19
  Speaker 5: if as human we've sorted all the problems of sustaining
• 6:23
  Speaker 5: reproduction and nutrition and health, I wonder whether the risks
• 6:27
  Speaker 5: of the dangers posed by cosmic rays will actually be
• 6:32
  Speaker 5: less in deep space. We do only then have to
• 6:36
  Speaker 5: worry about the problem of re entry into the new
• 6:40
  Speaker 5: stellar system.
• 6:41
  Speaker 6: I think generally it's possible, but you have the problem
• 6:45
  Speaker 6: that when you go fast you have cosmic rays that
• 6:47
  Speaker 6: are really high energy, and if you go slow, it
• 6:50
  Speaker 6: takes forever. So it's a tradeoff and you're lose in
• 6:53
  Speaker 6: both situations.
• 6:54
  Speaker 7: It depends on how far away the other stars. If
• 6:57
  Speaker 7: the star we're trying to get to is there one
• 6:59
  Speaker 7: that we're going to share our clouds with in about
• 7:01
  Speaker 7: a million years or so, then that's much more achievable
• 7:05
  Speaker 7: than a star on the other side of our galaxy.
• 7:07
  Speaker 8: I say no because the first two mens who leave
• 7:09
  Speaker 8: Earth going to interstellar space will not be alive because
• 7:12
  Speaker 8: it takes approximately twenty two to twenty five thousand years
• 7:14
  Speaker 8: to exit our solar system. And that opens up the
• 7:17
  Speaker 8: question about children in space to continue to journey, because
• 7:19
  Speaker 8: the adults who begin the journey will not live to
• 7:21
  Speaker 8: exit our solar system.
• 7:22
  Speaker 9: So no, if we allow for human reproduction all root,
• 7:26
  Speaker 9: which is a big if, humans would encounter significant survival challenges,
• 7:30
  Speaker 9: not the least which is that our physiology is ill
• 7:32
  Speaker 9: equipped to handle zero gravity and excessive radiation exposure in
• 7:36
  Speaker 9: the vein of we do not know what we do
• 7:38
  Speaker 9: not know. There are likely other factors that terrustrial living
• 7:41
  Speaker 9: either provides for us or protects us from that we
• 7:43
  Speaker 9: would faithfully and tragically encounter on the interstellar voyage.
• 7:48
  Speaker 10: We can imagine traveling to other solar systems, but can
• 7:51
  Speaker 10: we deal with all the questions radiation, food, power sources, generationships.
• 7:58
  Speaker 10: We just don't know enough at this point.
• 8:00
  Speaker 2: Those are super fun answers, And if you find yourself
• 8:03
  Speaker 2: speaking back to the podcast with your own answers, then
• 8:06
  Speaker 2: send us those answers and we'll put them on the
• 8:09
  Speaker 2: pod so that everyone else can hear what you have
• 8:11
  Speaker 2: to say. Just write to us to questions at Danielankelly
• 8:15
  Speaker 2: dot org and we will share your insights with the world.
• 8:18
  Speaker 1: Looking forward to hearing from you. And we've been very
• 8:20
  Speaker 1: excited to have more women sharing their responses lately, so
• 8:23
  Speaker 1: let's keep that up. Go women.
• 8:25
  Speaker 2: Well, do you think our listeners also have rose colored
• 8:27
  Speaker 2: glasses and they're underestimating the difficulty of traveling to space
• 8:31
  Speaker 2: or do you think they have a realistic sense.
• 8:33
  Speaker 1: We have a really nice range of people who are
• 8:36
  Speaker 1: super optimistic, and I would maybe say not quite reasonably so,
• 8:41
  Speaker 1: and then people who are maybe a bit more down
• 8:43
  Speaker 1: on the enterprise than is necessary. We've got a lot
• 8:46
  Speaker 1: of variability. I think it depends a lot on the
• 8:48
  Speaker 1: timeframe that you're willing to consider for this question.
• 8:50
  Speaker 2: All right, well, let's dig into the problem why space
• 8:53
  Speaker 2: travel is so much harder than airplane trips, or if
• 8:56
  Speaker 2: it's just airplane trips times a thousand, tell us what
• 8:59
  Speaker 2: basically are the obstacles here to traveling in safety and
• 9:03
  Speaker 2: comfort to another solar system.
• 9:05
  Speaker 1: Well, as you pointed out in the last episode, space
• 9:08
  Speaker 1: is vast, and so if we're going to Alpha Centauri,
• 9:11
  Speaker 1: that is four light years away. So with current technologies,
• 9:14
  Speaker 1: we're talking about eighty thousand years. That's a lot of
• 9:17
  Speaker 1: human generations.
• 9:18
  Speaker 2: That's a lot of movies to watch.
• 9:20
  Speaker 1: Wow, oh my gosh. Yeah, maybe in the next one
• 9:22
  Speaker 1: hundred years Marvel will make enough movies to get you
• 9:24
  Speaker 1: to Alpha Centauri.
• 9:26
  Speaker 2: I think there might be enough fast and furious movies
• 9:28
  Speaker 2: to make sure.
• 9:30
  Speaker 1: I would not make it to Alpha Centauri fast and
• 9:33
  Speaker 1: furious movies. I would rather push myself out the airlock.
• 9:36
  Speaker 2: But our he no, you're missing out, You're missing out.
• 9:38
  Speaker 2: Fast and furious is fantastic because they don't take themselves seriously.
• 9:41
  Speaker 2: Like every movie they have an even more ridiculous stunt.
• 9:45
  Speaker 2: They're like, oh yeah, how about a space shuttle. Okay,
• 9:47
  Speaker 2: how about a submarine on the ice with a torpedo.
• 9:51
  Speaker 2: It's ridiculous and fantastic and really creative. I watch a
• 9:54
  Speaker 2: lot of terrible movies, and there's always something new in
• 9:57
  Speaker 2: the Fast and Furius that makes me go, whoa that
• 10:00
  Speaker 2: it was cool. So yeah, don't overlook them.
• 10:02
  Speaker 1: Okay, all right, I'll take another look at the Fast
• 10:04
  Speaker 1: and Furious series. I didn't imagine I would say that
• 10:06
  Speaker 1: phrase today, but there you go.
• 10:07
  Speaker 2: But I don't think we want to travel the stars
• 10:09
  Speaker 2: fast and furious. I think it's kind of more like
• 10:11
  Speaker 2: slow and calm is the way to go.
• 10:13
  Speaker 1: That's what I would like, and with no explosions or
• 10:15
  Speaker 1: anything like that. So you said that we could get
• 10:17
  Speaker 1: to Alpha Centauri in forty years if you can travel
• 10:20
  Speaker 1: at ten percent the speed of light. Yeah, So we're
• 10:22
  Speaker 1: going to talk about a range of different options. What
• 10:24
  Speaker 1: if you could get there fast if the technology works out,
• 10:27
  Speaker 1: and what if you need to get there over the
• 10:29
  Speaker 1: course of multiple generations. So you need to have a
• 10:32
  Speaker 1: generational ship sometimes called an arc and this field has
• 10:35
  Speaker 1: a good sense of humor, so sometimes they call the
• 10:38
  Speaker 1: study archaeology also, yeah, which I love.
• 10:43
  Speaker 2: That is very cool.
• 10:45
  Speaker 1: All right, So one human thing we're going to need
• 10:47
  Speaker 1: to overcome is this whole money situation because the cost
• 10:50
  Speaker 1: of a project like this is probably going to be
• 10:53
  Speaker 1: massively prohibitive. So you talked about how much mass would
• 10:56
  Speaker 1: be needed to hold the propellant, and that for chemical
• 10:59
  Speaker 1: rockets the tank would have to be as big as Jupiter.
• 11:03
  Speaker 2: Yeah, and then you also need to somehow find that fuel.
• 11:05
  Speaker 9: Yeah.
• 11:05
  Speaker 2: Right, basically you have to use Jupiter as your rocket. Yeh.
• 11:08
  Speaker 1: Many layers of problems here. But you know, if you're
• 11:10
  Speaker 1: talking about bringing humans that are awake, you're also going
• 11:13
  Speaker 1: to need space for recreation areas, space for schooling, space
• 11:16
  Speaker 1: for medical facilities, places to grow food. The International Space
• 11:19
  Speaker 1: Station is the most expensive human made object ever and
• 11:22
  Speaker 1: it's clocking in at about one hundred and fifty billion
• 11:25
  Speaker 1: dollars and it usually holds seven people uncomfortably.
• 11:30
  Speaker 2: So this is going to cost a lot of money.
• 11:32
  Speaker 2: But we're basically just going to ignore the financial side
• 11:34
  Speaker 2: of the question.
• 11:35
  Speaker 1: We are, yes, right, So let's assume that money is
• 11:37
  Speaker 1: no longer an object. Yea, yeah, hey, that's right. Humanity
• 11:41
  Speaker 1: has decided we absolutely must do this. Okay, what kind
• 11:43
  Speaker 1: of problems are the humans going to encounter? As you
• 11:46
  Speaker 1: might remember from our conversations on Mars and the Moon,
• 11:49
  Speaker 1: space has a lot of radiation that is bad for humans.
• 11:53
  Speaker 1: It has two kinds of radiation that are not very
• 11:55
  Speaker 1: common here on Earth, and that scalactic cosmic radiation and
• 11:59
  Speaker 1: solar particle events. And these are bad for equipment and
• 12:03
  Speaker 1: for people. And I'm kicking over to Daniel tell us
• 12:05
  Speaker 1: about galactic cosmic radiation and solar particle events.
• 12:09
  Speaker 2: Yeah, so the Sun puts out a lot of light,
• 12:11
  Speaker 2: but it also shoots out a lot of other stuff.
• 12:14
  Speaker 4: You know.
• 12:14
  Speaker 2: They're protons, they're electrons. Basically, it's just spewing plasma. We
• 12:19
  Speaker 2: call this the solar wind, and it's moving at high speed.
• 12:22
  Speaker 2: So these particles are dangerous because any one of them
• 12:25
  Speaker 2: hits your body, tears through it like a little tiny bullet.
• 12:27
  Speaker 2: You can rip apart DNA, you can destroy cells. It's
• 12:30
  Speaker 2: not good. One random one you're probably fine, But you
• 12:33
  Speaker 2: take enough of these you're getting cancer. And down here
• 12:36
  Speaker 2: on the surface of the Earth. We don't worry about
• 12:37
  Speaker 2: this because while the solar wind is hitting the Earth,
• 12:40
  Speaker 2: the atmosphere protects us. It's an enormous, very thick, very
• 12:44
  Speaker 2: massive blanket. And the whole idea is that when you
• 12:46
  Speaker 2: go out into space, you no longer have that atmosphere,
• 12:49
  Speaker 2: so you have to replicate that with shielding. Galactic cosmic
• 12:53
  Speaker 2: rays are a whole other question. They're basically radiation from
• 12:56
  Speaker 2: other stuff in the galaxy, like the combined radiation from
• 12:58
  Speaker 2: other stars and from black holes and from other weird
• 13:02
  Speaker 2: stuff we've never even figured out, like there are particles
• 13:05
  Speaker 2: that are so high energy. There's nothing in the universe
• 13:08
  Speaker 2: we know of that can make particles go that fast,
• 13:11
  Speaker 2: and yet we see them. So there's like really fascinating
• 13:14
  Speaker 2: physics mysteries there. But from a human survival point of view,
• 13:17
  Speaker 2: you don't want these super duper high energy particles hitting you. Basically,
• 13:21
  Speaker 2: space is filled with tiny bullets, and you got to
• 13:23
  Speaker 2: go up there with a bulletproof vest.
• 13:25
  Speaker 1: I am always so impressed by how eloquent you are
• 13:27
  Speaker 1: when I put you on the spot, Bravo. So we're
• 13:29
  Speaker 1: going to need to shield against this kind of stuff.
• 13:31
  Speaker 1: And it's not just a problem for human bodies, it's
• 13:33
  Speaker 1: also a problem for our machines. Did I tell the
• 13:36
  Speaker 1: story on the show before about Terry Vertz and Samantha
• 13:39
  Speaker 1: Christofferetti when the ISS had a false alarm?
• 13:42
  Speaker 2: Oh? Tell us?
• 13:43
  Speaker 1: All right, So you've got Terry and Samantha in space
• 13:45
  Speaker 1: on the International Space Station and an alarm starts going
• 13:48
  Speaker 1: off and Terry's not immediately sure what this alarm means,
• 13:51
  Speaker 1: but Samantha has memorized all the alarms and it's an
• 13:54
  Speaker 1: ammonia leak. And on the US side, ammonia is used
• 13:58
  Speaker 1: to cool the space station is also toxic. So the
• 14:01
  Speaker 1: protocol for what you do when there's an ammonia leak
• 14:04
  Speaker 1: as you run over to the Russian side, you close
• 14:07
  Speaker 1: the first hatch, you take off your clothes. You close
• 14:10
  Speaker 1: the second hatch with you on the other side, you take.
• 14:13
  Speaker 2: Off your clothes. Why do you have to take off
• 14:15
  Speaker 2: your clothes as just make it more fun and dramatic.
• 14:17
  Speaker 1: Well, yeah, I mean one, sure, but also that ammonia
• 14:21
  Speaker 1: could cling to your clothes and you don't want to
• 14:22
  Speaker 1: bring it over to the Russian side. So you got
• 14:24
  Speaker 1: to hope the Russians have some undies they'll be willing
• 14:26
  Speaker 1: to loan you, and so they ran over. They closed
• 14:28
  Speaker 1: the first hatch, but they didn't smell the ammonia. And
• 14:31
  Speaker 1: this is an important sort of lesson about how humans respond,
• 14:35
  Speaker 1: like it sort of doesn't matter what protocols you put
• 14:37
  Speaker 1: into place. When one human is looking at another human
• 14:40
  Speaker 1: and they're both like, am I going to really see
• 14:42
  Speaker 1: you naked? Right now? They decided to just skip that
• 14:45
  Speaker 1: step and they went in with all of their clothes
• 14:47
  Speaker 1: over to the Russian module. It did turn out it
• 14:50
  Speaker 1: was a false alarm, and the reason you go to
• 14:52
  Speaker 1: the Russian module is because they use glycol to cool
• 14:54
  Speaker 1: their side, which is not as toxic, and so if
• 14:56
  Speaker 1: the leak was coming from anywhere, it was the US
• 14:58
  Speaker 1: side anyway. It was later determined that the most likely
• 15:03
  Speaker 1: reason that this alarm got switched on was because the
• 15:06
  Speaker 1: computer had been hit with galactic cosmic radiation, which messed
• 15:09
  Speaker 1: with the equipment and started setting off alarms. You could
• 15:12
  Speaker 1: have cancer, cognitive declines, your machines could start breaking down.
• 15:15
  Speaker 1: So this is a problem we need to take seriously.
• 15:18
  Speaker 2: Yeah, this is actually really fascinating from an engineering point
• 15:20
  Speaker 2: of view. You know, what's happening is that these particles
• 15:23
  Speaker 2: are passing through your equipment. Sensitive bits of it are
• 15:26
  Speaker 2: mostly made out of silicon, and when a high energy
• 15:28
  Speaker 2: particle passes through, it leaves a trail of ions, you know,
• 15:32
  Speaker 2: it like kicks electrons and leaves holes, and this is
• 15:35
  Speaker 2: how these things work also, right, they like separate the
• 15:37
  Speaker 2: holes and the electrons, and so all this equipment can
• 15:40
  Speaker 2: get like a false bit, like you can have a
• 15:42
  Speaker 2: zero in your memory and then they can turn into
• 15:44
  Speaker 2: a one or something, and so these kind of cosmic
• 15:46
  Speaker 2: ray bitflips are real concern and like massive data centers
• 15:50
  Speaker 2: worry about this also, but they have a lot of
• 15:52
  Speaker 2: error correction and so they have like duplications and cross
• 15:55
  Speaker 2: checking to basically remove this. So you can either have
• 15:58
  Speaker 2: a lot of duplication or you can try to make
• 16:00
  Speaker 2: get radiation hard by shielding it. The even folks who
• 16:02
  Speaker 2: are using diamonds instead of silicon, because diamond has a
• 16:06
  Speaker 2: lot of the same electrical properties, but it's radiation hard.
• 16:09
  Speaker 2: You can grow diamond, it's much more expensive and there's
• 16:11
  Speaker 2: not a huge industry for this. But like at the
• 16:14
  Speaker 2: large hadron collider, there's very intense radiation near all of
• 16:17
  Speaker 2: our sensitive detectors. So every couple of years, we've got
• 16:19
  Speaker 2: to pull it out and swap in a new one
• 16:21
  Speaker 2: because it's basically ruined.
• 16:23
  Speaker 1: Wow.
• 16:23
  Speaker 2: So, yeah, electronics are very sensitive to high levels of radiation.
• 16:27
  Speaker 2: And if you are relying on your electronics to keep
• 16:30
  Speaker 2: you alive and an eighty thousand year journey in all
• 16:32
  Speaker 2: of your grandkids and great grandkids, then yeah, you want
• 16:35
  Speaker 2: those things to work.
• 16:36
  Speaker 1: Yeah. And so the shielding could come in the form
• 16:38
  Speaker 1: of things like water, like you could store your water
• 16:40
  Speaker 1: supply on the outside. Would that help with galctic cosmic
• 16:43
  Speaker 1: radiation too, Daniel.
• 16:45
  Speaker 2: Yeah, with various kinds of it. Yeah, okay, but mostly
• 16:47
  Speaker 2: you basically just need high Z mass, like you need
• 16:50
  Speaker 2: atoms with a lot of protons and neutrons between you
• 16:54
  Speaker 2: and the radiation.
• 16:55
  Speaker 1: Got it. I've also seen proposals for scraping the regolith
• 16:58
  Speaker 1: off the Moon and padding your interstellarship with it. That
• 17:01
  Speaker 1: would be complicated, but it's a solution.
• 17:03
  Speaker 2: That would be pretty cool because then your ship looks
• 17:05
  Speaker 2: like a rock, you know, yeah, like floating through space,
• 17:08
  Speaker 2: like masquerading as an asteroid or something.
• 17:12
  Speaker 1: Well, another complicated problem we're going to need to solve
• 17:14
  Speaker 1: is what do you do about no gravity.
• 17:16
  Speaker 2: Right, But the takeaway from the shielding is an important one. Right.
• 17:18
  Speaker 2: It makes our ship big and massive and heavy, and
• 17:21
  Speaker 2: that makes it expensive. Right, But fortunately money is no
• 17:24
  Speaker 2: hurdle for.
• 17:25
  Speaker 1: Us, so cool, that's right. In space manufacturing might help
• 17:28
  Speaker 1: with this a lot. So you know, you could, like
• 17:29
  Speaker 1: I mentioned, go get the regulis from the surface of
• 17:31
  Speaker 1: the Moon, but also you could go to the asteroids
• 17:34
  Speaker 1: and extract water from the asteroids. In that way, you
• 17:36
  Speaker 1: don't have to pay to boost it from Earth. But
• 17:37
  Speaker 1: one way or another, it's going to be an expensive,
• 17:40
  Speaker 1: massive project.
• 17:41
  Speaker 2: Yeah, all right, So problem number one is radiation.
• 17:44
  Speaker 1: Yes, and problem number two is going to make the
• 17:46
  Speaker 1: design of our vehicle even more complicated. And problem number
• 17:49
  Speaker 1: two is that there's no gravity in deep space. So
• 17:52
  Speaker 1: we know from astronauts on the International Space Station and
• 17:55
  Speaker 1: the space stations that came before that when they are
• 17:58
  Speaker 1: essentially in free fall and feeling the equivalent of no gravity,
• 18:01
  Speaker 1: that their bones start breaking down, their muscles start breaking down.
• 18:04
  Speaker 1: And the gravity on Earth and the fact that we're
• 18:06
  Speaker 1: constantly moving around and submitting our bones and muscles to gravity,
• 18:11
  Speaker 1: and then the pressure of our bodies as we run
• 18:13
  Speaker 1: around that makes our bones and muscles strong. That's like
• 18:16
  Speaker 1: a que Our bodies need to keep these things toned.
• 18:19
  Speaker 1: Without those cues, they just start to decay because you're
• 18:21
  Speaker 1: not using them, so bodies start falling apart. Additionally, we
• 18:24
  Speaker 1: see declines in vision, and we think that's because the
• 18:27
  Speaker 1: fluids in our bodies without gravity to pull them down,
• 18:30
  Speaker 1: sort of accumulate near our heads and change the shape
• 18:32
  Speaker 1: of our eyes. There's also some evidence that there could
• 18:35
  Speaker 1: be some cognitive declines. Basically, we're gonna want some gravity
• 18:40
  Speaker 1: when we're living out our lives on a ship, and folks.
• 18:42
  Speaker 2: Out there might be thinking, well, you know, we're adapted
• 18:45
  Speaker 2: to life on Earth, but if we spend it long
• 18:47
  Speaker 2: enough in space, maybe our bodies are just going to adapt.
• 18:49
  Speaker 2: Maybe we don't need those bones and those muscles because hey,
• 18:52
  Speaker 2: we're all floating around to the Blue Danube anyway, right,
• 18:55
  Speaker 2: Why do we care about degradation of our bones and
• 18:58
  Speaker 2: our muscles if we're just floating in space.
• 19:00
  Speaker 1: Yeah, so that's a great question. We don't actually know
• 19:02
  Speaker 1: that we could survive long term. So the longest anyone
• 19:05
  Speaker 1: has ever been in space, I think, is four hundred
• 19:08
  Speaker 1: and thirty seven days. That was Valeri Polyi call. So
• 19:11
  Speaker 1: we don't even have like more than a year and
• 19:13
  Speaker 1: a half of consecutive time in space. We know that
• 19:16
  Speaker 1: astronauts lose something like one percent of the density of
• 19:19
  Speaker 1: their hip bone per month, and we don't know if
• 19:22
  Speaker 1: that tapers off eventually. But if you imagine trying to
• 19:25
  Speaker 1: have babies in space, hold.
• 19:26
  Speaker 2: On, wait, I'm gonna imagine it. Hold on. Hmmm, yeah
• 19:29
  Speaker 2: that seems gooey.
• 19:30
  Speaker 1: Yeah, yeah, that is such a dive response. The gooeyness
• 19:33
  Speaker 1: is not a problem.
• 19:34
  Speaker 2: Man, But now you're in space, you have like weird
• 19:36
  Speaker 2: balls of goo.
• 19:36
  Speaker 1: It's oh, imagine trying to do a C section in
• 19:39
  Speaker 1: space with like the blood floating around your head anyway unpleasants.
• 19:43
  Speaker 2: Or imagine like a diaper explosion, you know, like loss
• 19:46
  Speaker 2: of containment in space. I don't know about that loss
• 19:48
  Speaker 2: of containment. You've had that experience, you know what I'm
• 19:52
  Speaker 2: talking about. We've all had the like Transatlantic flight with
• 19:55
  Speaker 2: loss of containment of the diaper like ooh, no, I.
• 19:57
  Speaker 1: Did right when a plane was taking off. My had
• 20:00
  Speaker 1: a blowout on my lap and we couldn't get up
• 20:02
  Speaker 1: for thirty minutes, and oh man, nobody liked me. And
• 20:05
  Speaker 1: it brought a change of clothes for her, but not
• 20:07
  Speaker 1: for me, but she sat on my lap anyway. All Right,
• 20:10
  Speaker 1: these problems can only get more difficult in space. So
• 20:13
  Speaker 1: we don't know, for example, that women's hips will be
• 20:15
  Speaker 1: able to survive childbirth, and we just generally don't know
• 20:18
  Speaker 1: if you can survive a lifetime. But maybe you can.
• 20:21
  Speaker 1: So let's say that you can. Let's say that not
• 20:23
  Speaker 1: only can you survive, but you can also go through
• 20:25
  Speaker 1: reproduction in zero gravity, which again I think is highly unlikely,
• 20:28
  Speaker 1: but we don't have a lot of good science for that.
• 20:30
  Speaker 1: There's a lot of reasons why you'd want at least
• 20:32
  Speaker 1: a little bit of gravity, and you know, a lot
• 20:34
  Speaker 1: of them have to do with things like using the restroom.
• 20:37
  Speaker 1: So we talked a little bit about how that's unpleasant.
• 20:40
  Speaker 1: At the start of the show.
• 20:42
  Speaker 2: My gooey imagination is filling in the details for me.
• 20:44
  Speaker 1: Yes, oh oh yeah, you're really into Guey today. It's
• 20:47
  Speaker 1: only going to go downhill from here. When I was
• 20:50
  Speaker 1: researching a city on Mars, every space vehicle that I
• 20:53
  Speaker 1: read about had a story about escapees, where the escapees
• 20:57
  Speaker 1: were like bits of feces that kind of floated out.
• 20:59
  Speaker 1: It's hard to keep things clean. Everything is more of
• 21:02
  Speaker 1: a pain in the rear end. If you have just
• 21:04
  Speaker 1: a little bit of gravity, Surgery gets easier, restrooms get easier,
• 21:08
  Speaker 1: farming gets easier. We're almost certainly going to need at
• 21:12
  Speaker 1: least a little bit of gravity just to like hold
• 21:14
  Speaker 1: our stuff down and make our lives easy.
• 21:16
  Speaker 2: And if you hope that your descendants or whoever is
• 21:18
  Speaker 2: arriving in the distant Solar System is going to be
• 21:21
  Speaker 2: able to get off the ship and walk around on
• 21:23
  Speaker 2: this new alien planet, they're going to have to have
• 21:24
  Speaker 2: some bones and muscles, right, So it makes sense to
• 21:26
  Speaker 2: maintain that capacity on the trip.
• 21:29
  Speaker 1: Absolutely. So not only are we going to have this
• 21:31
  Speaker 1: massive object, but this massive object needs to have at
• 21:33
  Speaker 1: least some areas that are spinning to create artificial gravity,
• 21:38
  Speaker 1: so that you've got some of that force keeping your
• 21:40
  Speaker 1: body strong or helping the brown trout swim down the
• 21:43
  Speaker 1: river in the right direction.
• 21:44
  Speaker 2: All right, So we've talked about radiation and that might
• 21:47
  Speaker 2: be a solvable problem with enough shielding, and we talked
• 21:49
  Speaker 2: about gravity might be a solvable problem if we have
• 21:51
  Speaker 2: acceleration or something spinning or something like that. So so far,
• 21:55
  Speaker 2: I'm feeling kind of optimistic about how our kids' kids, kids' kids'
• 21:59
  Speaker 2: kids might be able to walk off the ship and
• 22:02
  Speaker 2: stand on a planet around Alpha Centauri. So let's take
• 22:05
  Speaker 2: a break, and when we come back, Kelly's going to
• 22:06
  Speaker 2: tell us about how that's all an impossible dream.
• 22:11
  Speaker 1: I'm not trying to be negative today.
• 22:14
  Speaker 2: The facts that we're going to get into though, all right,
• 22:33
  Speaker 2: So we're back and we're talking about whether we could
• 22:35
  Speaker 2: survive an interstellar trip, whether it's a good idea to
• 22:39
  Speaker 2: build an arc where people can have their babies and
• 22:41
  Speaker 2: their babies babies babies can one day visit an alien
• 22:45
  Speaker 2: solar system, or whether these problems are insurmountable. We've talked
• 22:49
  Speaker 2: about radiation, We've talked about money, we've talked about gravity.
• 22:52
  Speaker 2: Now Kelly tell us about knowledge. Why do we need
• 22:55
  Speaker 2: to make sure knowledge doesn't decay along the way we.
• 22:58
  Speaker 1: We've already talked about how difficult it is to store
• 23:01
  Speaker 1: knowledge in computers, or at least how careful you need
• 23:03
  Speaker 1: to be to protect it from radiation. But another problem
• 23:06
  Speaker 1: you're going to have is that the farther you get
• 23:08
  Speaker 1: from Earth, the longer the communication delay. So if people
• 23:12
  Speaker 1: are living on Mars, for example, there's a minimum three
• 23:15
  Speaker 1: minute communication delay, just because it takes a long time
• 23:17
  Speaker 1: for the message to go from Mars to Earth and
• 23:20
  Speaker 1: then from Earth to Mars when you're ready to respond.
• 23:22
  Speaker 2: I think that's really fascinating because you know, the Earth
• 23:25
  Speaker 2: is not small, but it's small compared to the speed
• 23:27
  Speaker 2: of light, So you can have what feels like an
• 23:28
  Speaker 2: instantaneous phone call with somebody in Tokyo, right, and the
• 23:32
  Speaker 2: lag is imperceptible. But then once you go to the
• 23:34
  Speaker 2: Moon or to Mars, like now, it really ruins what
• 23:38
  Speaker 2: it feels like to have a conversation.
• 23:39
  Speaker 3: Right.
• 23:39
  Speaker 2: You can ask a question, you got to wait like
• 23:41
  Speaker 2: six minutes to hear the answer. That's like not a conversation,
• 23:45
  Speaker 2: it's more like writing letters back and forth.
• 23:47
  Speaker 1: It is. Yeah, I mean, I think even on the
• 23:48
  Speaker 1: Moon you can have a close to real time conversation,
• 23:52
  Speaker 1: maybe a little bit of an awkward delay. But when
• 23:54
  Speaker 1: you get to Mars, it's a minimum of three minutes,
• 23:56
  Speaker 1: a maximum of something like twenty to twenty two minutes.
• 23:59
  Speaker 1: But when you're starting to get to Alpha Centauri, it's
• 24:02
  Speaker 1: just going to keep extending, extending, extending, until at some
• 24:05
  Speaker 1: point you're not communicating anymore.
• 24:07
  Speaker 2: So for example, if you like need it support, you're like, hey,
• 24:10
  Speaker 2: my MacBook is crashing. You don't want to wait four
• 24:13
  Speaker 2: years for the answer to be like, turn it on
• 24:14
  Speaker 2: and off again.
• 24:15
  Speaker 1: That's right, it's not helpful anymore. At that point you've
• 24:17
  Speaker 1: probably figured.
• 24:18
  Speaker 2: It out, hope, so, or you're all dead.
• 24:20
  Speaker 1: Yeah, And I mean that also means at some point
• 24:22
  Speaker 1: you're gonna stop benefiting from any new knowledge that is
• 24:26
  Speaker 1: created on Earth because it's gonna be hard to get
• 24:28
  Speaker 1: it to you and probably at some point impossible to
• 24:29
  Speaker 1: get it to you. But it also means if somebody
• 24:32
  Speaker 1: has an illness that you don't have anyone on the
• 24:34
  Speaker 1: ship who's an expert in that you're on your own
• 24:36
  Speaker 1: the surgical procedure that you're doing. You better hope you
• 24:39
  Speaker 1: downloaded a good YouTube video for it, because nobody's gonna
• 24:42
  Speaker 1: walk you through it in real time. You really are
• 24:44
  Speaker 1: on your own.
• 24:45
  Speaker 2: Yeah, you can't look things up unless you bring like
• 24:47
  Speaker 2: all of human knowledge with you somehow download Wikipedia onto
• 24:51
  Speaker 2: your ship's computers. I mean that seems that could be
• 24:53
  Speaker 2: a good idea anyway, doesn't it.
• 24:54
  Speaker 1: No, absolutely, yes, for both entertainment purposes and you know,
• 24:58
  Speaker 1: knowledge purposes. You should bring as much information with you
• 25:01
  Speaker 1: as you can. That would absolutely be worth the storage space.
• 25:04
  Speaker 1: In my opinion, what.
• 25:05
  Speaker 2: Do you think takes more storage space? Like Wikipedia or
• 25:07
  Speaker 2: all the Fast and Furious movies?
• 25:10
  Speaker 1: Are you taking Wikipedia in every language?
• 25:12
  Speaker 2: Ooh question?
• 25:14
  Speaker 1: I don't know.
• 25:15
  Speaker 2: We better though, yeah, including the Scottish one. That the
• 25:17
  Speaker 2: Scottish one turns out to be totally made up.
• 25:19
  Speaker 1: There's no Scottish wikip Wait what There.
• 25:21
  Speaker 2: Is a Scottish Wikipedia, but it's mostly written by a
• 25:23
  Speaker 2: guy who just invented what he thought Scottish should sound like.
• 25:26
  Speaker 2: Oh my god, yeah, it's bad.
• 25:28
  Speaker 1: I am regularly amazed by the amount of time that
• 25:32
  Speaker 1: humans are willing to put into messing with each other.
• 25:35
  Speaker 1: That must have taken a long time.
• 25:37
  Speaker 2: Oh he thought he was doing something good. No, he
• 25:39
  Speaker 2: was like, hey, nobody else has done this, and I
• 25:41
  Speaker 2: know how to do it right, so my goodness, the
• 25:44
  Speaker 2: best intentions. Anyway, you should read that story. It's hilarious. Okay,
• 25:47
  Speaker 2: but anyway, what is the impediment though, to just bringing
• 25:50
  Speaker 2: all of human knowledge with us and saying like, all right,
• 25:52
  Speaker 2: we're gonna be cut off from the mothership or we're
• 25:54
  Speaker 2: not going to get the latest advancements in quantum computing
• 25:56
  Speaker 2: at the same moment. Maybe they can beam them to
• 25:59
  Speaker 2: us as they come in who are a little behind.
• 26:01
  Speaker 2: But why can't we just bring it all with us.
• 26:03
  Speaker 1: You can bring a ton of knowledge with you, but
• 26:05
  Speaker 1: you know, if you set me down next to a
• 26:07
  Speaker 1: bunch of textbooks on quantum computing, I could do nothing
• 26:10
  Speaker 1: with that information. Like I mean, maybe after a couple
• 26:13
  Speaker 1: generations I could. But this ties into the next problem
• 26:15
  Speaker 1: that we're going to deal with, which is you have
• 26:17
  Speaker 1: to pick whatich humans you send with you, and what
• 26:20
  Speaker 1: kind of knowledge they have, and how many of them
• 26:21
  Speaker 1: you get. But I'm guessing you had another limitation in mind.
• 26:26
  Speaker 1: Was it how many hard drives you'd have to bring?
• 26:28
  Speaker 1: Or should I stop trying to guess what you're thinking.
• 26:30
  Speaker 2: No, I think that your point is valid that you
• 26:32
  Speaker 2: can bring a bunch of knowledge, but just having that
• 26:34
  Speaker 2: knowledge isn't enough. You need people who can digest it
• 26:37
  Speaker 2: and people who can put it to work. So you're
• 26:38
  Speaker 2: essentially saying, make sure you bring enough physicists on board.
• 26:41
  Speaker 1: You know, you guys are good for a lot of stuff.
• 26:44
  Speaker 1: I don't know how many practical problems. Also, you have
• 26:46
  Speaker 1: to worry about like hygiene interstellar trip, but you should
• 26:54
  Speaker 1: bring a couple cleanly physicists probably, Yeah.
• 26:57
  Speaker 2: I think the real problem here is that you need
• 26:59
  Speaker 2: a breadth of notice, right, And so there's a question of,
• 27:01
  Speaker 2: like what is the minimum size of a community that
• 27:04
  Speaker 2: has enough technical knowledge and expertise to basically run independently
• 27:10
  Speaker 2: of Earth, Because it's not like two people, it's not
• 27:12
  Speaker 2: ten people. And I'm guessing that's where you're going to
• 27:14
  Speaker 2: go next, is like how big a community you need
• 27:17
  Speaker 2: not just have the knowledge, but also to like have
• 27:19
  Speaker 2: healthy babies.
• 27:20
  Speaker 1: Yeah, so I'm going to be focusing on the healthy
• 27:21
  Speaker 1: babi's part, but this occupation's part is really important, and
• 27:25
  Speaker 1: it's very hard to have a concrete answer for it
• 27:27
  Speaker 1: because it depends on what you're willing to live without.
• 27:29
  Speaker 1: I heard once that there's something like one hundred thousand
• 27:32
  Speaker 1: medical specialties, and that number seems unreasonably large. But let's
• 27:36
  Speaker 1: even say there's like a thousand medical specialties. Okay, you'd
• 27:39
  Speaker 1: probably want one person from each of those specialties, or
• 27:43
  Speaker 1: like duplicates of all of those people, but you also
• 27:46
  Speaker 1: need janitors and plumbers and engineers and farmers, and there's
• 27:51
  Speaker 1: just so many different kinds of people you would like
• 27:53
  Speaker 1: to have there, but you might not be able to
• 27:55
  Speaker 1: have everyone you want there. Like, you know, you probably
• 27:58
  Speaker 1: couldn't have three of every remedical specialist if there are
• 28:01
  Speaker 1: one hundred thousand kinds, So you're gonna have to sort
• 28:03
  Speaker 1: of pick and choose and decide what you're willing to
• 28:05
  Speaker 1: do without.
• 28:06
  Speaker 2: I think there's also an interesting interplay there between are
• 28:09
  Speaker 2: you just trying to survive the trip or are you
• 28:11
  Speaker 2: trying to bring the seeds of a future civilization with you?
• 28:14
  Speaker 2: Because think about just like pencils. Okay, you need a
• 28:17
  Speaker 2: lot of pencils on an eighty thousand year journey. Maybe
• 28:20
  Speaker 2: you could just stock a bunch of pencils, right, bring
• 28:22
  Speaker 2: a bunch of pencils, or like light bulbs or whatever,
• 28:24
  Speaker 2: and you might be able to survive the journey and
• 28:27
  Speaker 2: not use up all the light bulbs and pencils. But
• 28:28
  Speaker 2: once you get there, you might still want light bulbs
• 28:30
  Speaker 2: and pencils in a thousand years. And so what you
• 28:33
  Speaker 2: need to do is bring like the manufacturing capacity to
• 28:37
  Speaker 2: produce all of the goodies that we expect for a
• 28:40
  Speaker 2: certain quality of life, or to severely restrict the goodies
• 28:44
  Speaker 2: that you're expecting these people to live without. So you
• 28:47
  Speaker 2: really need to bring like your entire manufacturing supply chain
• 28:51
  Speaker 2: and pipeline with you if you're going to seed a
• 28:53
  Speaker 2: civilization on the other end of this, not just like
• 28:56
  Speaker 2: visit Alpha Centauri and turn around and come back.
• 28:58
  Speaker 1: Yeah, so let's jump for a second to a conversation
• 29:00
  Speaker 1: about what you bring with you. So, yeah, you would
• 29:02
  Speaker 1: want to maybe bring all the manufacturing stuff to make pencils. Additionally,
• 29:06
  Speaker 1: we should have invited Katrina on the show briefly, because
• 29:08
  Speaker 1: you're going to want to make sure, for example, you
• 29:10
  Speaker 1: have a diversity of microbes, But how do you know
• 29:12
  Speaker 1: which ones to bring?
• 29:13
  Speaker 2: You just bring all the poop on Earth. That's the
• 29:15
  Speaker 2: easy solution, that's what she would say.
• 29:16
  Speaker 1: Okay, but a lot of that poop on Earth has parasites,
• 29:19
  Speaker 1: And while I don't want to live in a world
• 29:21
  Speaker 1: without interesting parasites to study, I think most people would,
• 29:24
  Speaker 1: although I prefer parasites that aren't infecting people. But anyway, so, yeah,
• 29:28
  Speaker 1: you got to figure out what kind of microbes and
• 29:29
  Speaker 1: that requires knowledge that we don't necessarily even have yet.
• 29:33
  Speaker 1: What kind of microbes do you want to bring with you?
• 29:35
  Speaker 1: But you also need to bring medicine, but medicine expires,
• 29:38
  Speaker 1: and eighty thousand years is a long time, so you're
• 29:40
  Speaker 1: probably going to want to bring the equipment that you
• 29:42
  Speaker 1: need to make more medicine. And there are some designs
• 29:44
  Speaker 1: for three D printers that will print medicine on demand,
• 29:47
  Speaker 1: but you need to make sure you've got the raw
• 29:49
  Speaker 1: materials for that.
• 29:50
  Speaker 2: Yeah, exactly. It feels like you're cutting that very tip
• 29:53
  Speaker 2: off a very complex pyramid of manufacturing and civilization, and
• 29:59
  Speaker 2: it's going to rumble eventually. It feels very difficult to
• 30:02
  Speaker 2: maintain the same level of civilization if you're not bringing
• 30:05
  Speaker 2: the whole pyramid with you. And it turns out the
• 30:07
  Speaker 2: pyramid is huge, right, Like, just to make a pencil
• 30:10
  Speaker 2: requires an enormous manufacturing capacity and lots of different specialties.
• 30:14
  Speaker 1: Our global supply chains are amazing. We rely on them
• 30:17
  Speaker 1: for so many things. That pencil takes a million people.
• 30:20
  Speaker 1: Thing came from somewhere in one of these days. I
• 30:22
  Speaker 1: want to figure out, was it a Milton Friedman essay?
• 30:24
  Speaker 2: I do no holpu with't Malcolm Gladwell, because you can't
• 30:27
  Speaker 2: trust anything in these.
• 30:30
  Speaker 1: We're on the record now, all right, let's go ahead
• 30:32
  Speaker 1: and just accept that there's a lot of stuff that
• 30:35
  Speaker 1: you're going to need to bring if you want to
• 30:37
  Speaker 1: keep your standard of living reasonably high, and also a
• 30:39
  Speaker 1: lot of stuff that you're going to need to bring
• 30:41
  Speaker 1: or be able to build so that you can replace
• 30:44
  Speaker 1: parts of your ship as they break down over time
• 30:47
  Speaker 1: in the very harsh environment of space. So now let's
• 30:49
  Speaker 1: jump to biology, the good part. Let's get to the
• 30:51
  Speaker 1: good part.
• 30:51
  Speaker 2: All right, Are we talking about parasites? Minimum number of
• 30:54
  Speaker 2: parasites to bring to allisantaries?
• 30:56
  Speaker 1: Unfortunately, No, I couldn't figure out a way to really
• 30:59
  Speaker 1: shoehorn parasites and more than once.
• 31:01
  Speaker 2: I'm ready for it though, when you ring it up,
• 31:03
  Speaker 2: I'm ready for it.
• 31:03
  Speaker 1: Okay, good, But how.
• 31:05
  Speaker 2: Big a group do we need, like biologically to keep
• 31:07
  Speaker 2: our community healthy and to make sure we don't all
• 31:10
  Speaker 2: suffer from some genetic defect that like one guy has
• 31:14
  Speaker 2: on board? How big a population do we need?
• 31:16
  Speaker 1: Yeah, this is a really difficult question. So we don't
• 31:18
  Speaker 1: necessarily know what kind of diversity we need. So it
• 31:21
  Speaker 1: would be great to have people, for example, that are
• 31:24
  Speaker 1: resistant to radiation in case we can't shield all of it.
• 31:27
  Speaker 1: But we don't really know what genes are important for
• 31:29
  Speaker 1: that at this point. So the more diversity you can have,
• 31:33
  Speaker 1: the better. You also want people who are not closely
• 31:36
  Speaker 1: related to each other, because we all have some genes
• 31:40
  Speaker 1: that are carrying the code for negative traits. So you know,
• 31:44
  Speaker 1: it could be sickle cell anemia or something like that,
• 31:47
  Speaker 1: where if you get two versions of the gene that
• 31:49
  Speaker 1: cause the disease, you're in a lot more trouble than
• 31:51
  Speaker 1: if you just have one.
• 31:52
  Speaker 2: I wonder, from an evolution air point of view, if
• 31:54
  Speaker 2: this is a scenario where you actually want to be
• 31:56
  Speaker 2: susceptible to radiation because it induces a higher mutation rate
• 32:00
  Speaker 2: in your babies. And that might mean that you lose
• 32:02
  Speaker 2: a bunch because like they have bad mutations, But you
• 32:04
  Speaker 2: also might like invent some new weird like spacefaring, hearty
• 32:08
  Speaker 2: human that can like I don't know, extrude pencils from
• 32:11
  Speaker 2: some new orifice or something you're useful. I don't know, Like,
• 32:14
  Speaker 2: is there a possibility there that more mutation might actually
• 32:16
  Speaker 2: be beneficial?
• 32:17
  Speaker 1: So mutation is a mechanism through which you get more
• 32:21
  Speaker 1: genetic diversity, and some of that could be good. I
• 32:24
  Speaker 1: think our expectation would be statistically, you'd probably get a
• 32:29
  Speaker 1: lot more things breaking than a lot more things resulting
• 32:32
  Speaker 1: in pencils coming out of your nose at appropriate times
• 32:36
  Speaker 1: or something. And I think a lot of those mutations
• 32:38
  Speaker 1: are going to be you know, like causing cancer as
• 32:41
  Speaker 1: you're older, and not necessarily resulting in like really well
• 32:43
  Speaker 1: adapted babies. But who knows, who knows? All right, So
• 32:46
  Speaker 1: I've seen a bunch of estimates for how many people
• 32:49
  Speaker 1: you need, and you do need to be careful about
• 32:51
  Speaker 1: who these people are. So like, yes, we talked about
• 32:53
  Speaker 1: you want doctors and stuff like that, but when you're
• 32:55
  Speaker 1: thinking about the number of people you need, the number
• 32:58
  Speaker 1: of people over sixty, it's great to have their knowledge,
• 33:00
  Speaker 1: great to have their help, but they're not going to
• 33:02
  Speaker 1: be contributing to having children. So you need to think
• 33:05
  Speaker 1: about the number of reproductively aged individuals. And you need
• 33:09
  Speaker 1: to think a little bit about the mix of people.
• 33:11
  Speaker 1: So if you bring you know, ten thousand men, you
• 33:14
  Speaker 1: better also have artificial wounds or something at that point.
• 33:17
  Speaker 1: So you need to think about the makeup.
• 33:19
  Speaker 2: Well, dig into that for a moment for us, Like
• 33:21
  Speaker 2: what is it best gender ratio? I mean, because like
• 33:23
  Speaker 2: a woman can't be pregnant from two men simultaneously, but
• 33:25
  Speaker 2: a man can have multiple partners.
• 33:27
  Speaker 1: It depends on what your goal is, and frankly, it
• 33:30
  Speaker 1: depends on what your culture is willing to accept, because
• 33:32
  Speaker 1: I think you don't want to send people into interstellar
• 33:34
  Speaker 1: space under conditions that they would, you know, find abhorrent. Yes,
• 33:37
  Speaker 1: if your goal is to just have as many babies
• 33:40
  Speaker 1: as possible, and you've set up the interstellar ship to
• 33:43
  Speaker 1: be able to scale, to feed and provide oxygen for
• 33:46
  Speaker 1: a rapidly expanding population, then you could send exclusively women
• 33:50
  Speaker 1: who got pregnant using embryos that you sent with you.
• 33:54
  Speaker 1: There are ways to maximize the speed at which the
• 33:57
  Speaker 1: population increases, but I don't necessarily know that the goal
• 34:00
  Speaker 1: and root is going to be to increase numbers as
• 34:03
  Speaker 1: fast as possible, because if you just wanted to have
• 34:05
  Speaker 1: a lot of people, you could have just started with
• 34:07
  Speaker 1: a lot more people. So I think you want to
• 34:09
  Speaker 1: find a makeup where you can sustain your population numbers,
• 34:12
  Speaker 1: and I don't necessarily know if the best way to
• 34:14
  Speaker 1: go is fifty to fifty.
• 34:16
  Speaker 2: Well, I think your point is a good one, though.
• 34:17
  Speaker 2: If you want your people to be happy, then you're
• 34:19
  Speaker 2: going to have to create an environment they're going to
• 34:21
  Speaker 2: like to live in. And currently most people enjoy monogamous
• 34:25
  Speaker 2: relationships or you know, one to one ratios, which means
• 34:28
  Speaker 2: you're going to need roughly a gender balance.
• 34:31
  Speaker 1: So I found an estimate where someone did a computer
• 34:34
  Speaker 1: simulation and they found that you could possibly get away
• 34:37
  Speaker 1: with ninety eight people.
• 34:38
  Speaker 2: If ninety eight thousand or ninety eight people.
• 34:41
  Speaker 1: Ninety eight individuals. What if every generation they mate it
• 34:47
  Speaker 1: with whoever a computer program told them to mate with
• 34:50
  Speaker 1: based on their genetic makeup. So this is an interesting
• 34:53
  Speaker 1: thought experiment for a lower bound but if you're thinking
• 34:56
  Speaker 1: about what humans are willing to accept, that's probably not
• 34:59
  Speaker 1: going to work out.
• 35:00
  Speaker 2: And for this study, how do they define success? You
• 35:03
  Speaker 2: have like a population downstream that's healthy and doesn't have
• 35:08
  Speaker 2: a lot of recessive traits that are hurting people.
• 35:10
  Speaker 1: I forget the exact details, but it was something like
• 35:13
  Speaker 1: after five generations, would you expect the population to still
• 35:16
  Speaker 1: persist or would they have had inbreeding problems or something
• 35:19
  Speaker 1: like that.
• 35:19
  Speaker 2: Well, it's really fascinating because I've heard some of these
• 35:22
  Speaker 2: studies that speculate the humanity might have had bottlenecks early on,
• 35:26
  Speaker 2: you know, down to like as many as ten thousand
• 35:28
  Speaker 2: individuals on the planet, and here we are, you know,
• 35:31
  Speaker 2: eight billion people later doing pretty well. So it's not
• 35:34
  Speaker 2: implausible to me that you could get down to a
• 35:36
  Speaker 2: few thousand. Ninety eight seems kind of crazy.
• 35:39
  Speaker 1: And there are plenty of people who will also point
• 35:41
  Speaker 1: out that there are indigenous peoples living in populations of
• 35:44
  Speaker 1: something like one hundred to five hundred. But what those
• 35:47
  Speaker 1: numbers often miss is that those indigenous populations are often
• 35:51
  Speaker 1: interacting with others and intermarrying, and so actually the population
• 35:55
  Speaker 1: that is interbreeding is much larger than the individual communities themselves.
• 35:59
  Speaker 1: But yeah, I've I've seen estimates that seem pretty reasonable
• 36:01
  Speaker 1: that range from about five thousand to forty thousand people
• 36:05
  Speaker 1: of reproductive age. The forty thousand numbers seemed a little
• 36:08
  Speaker 1: bit more realistic to me. So it was taking into
• 36:10
  Speaker 1: account the ability to survive five generations even if a
• 36:15
  Speaker 1: black plague like catastrophe comes along. And so this is
• 36:19
  Speaker 1: incorporating like what if some bacteria in our gut mutate
• 36:23
  Speaker 1: and kills twenty five percent of us, Like you might
• 36:26
  Speaker 1: have to assume that every once in a while you're
• 36:27
  Speaker 1: going to lose people. So estimates range from ninety eight
• 36:31
  Speaker 1: to about forty thousand, and really depend on the assumptions
• 36:33
  Speaker 1: you're making well.
• 36:34
  Speaker 2: Keeping in mind our constraints. Even if money isn't an optical,
• 36:37
  Speaker 2: of course, in reality it is. And we know that
• 36:39
  Speaker 2: size is an issue and fuel and all that stuff,
• 36:42
  Speaker 2: and so if what we want to do is keep
• 36:44
  Speaker 2: the ship small, then we want to keep these numbers low.
• 36:47
  Speaker 2: And that was really interested in your comment about how
• 36:49
  Speaker 2: you could keep it down to around one hundred if
• 36:51
  Speaker 2: people accepted, you know, computer assigned dating. And I'm wondering
• 36:55
  Speaker 2: how far we could push that, Like, could we make
• 36:57
  Speaker 2: an even lower if we assume some sort of technology
• 37:00
  Speaker 2: to like modify your genetics or correct issues or something
• 37:05
  Speaker 2: that couldn't the interaction between biology and technology really change
• 37:08
  Speaker 2: how small we could go.
• 37:09
  Speaker 1: I hear a lot of engineers propose stuff like this,
• 37:11
  Speaker 1: and it totally makes sense. It's true, it could work,
• 37:13
  Speaker 1: But when ideas like this come like head to head
• 37:16
  Speaker 1: with human behavior, they tend to fall apart. I mean,
• 37:19
  Speaker 1: you could have five women who start the trip with
• 37:22
  Speaker 1: a vat of freeze dried sperm from lots of different people,
• 37:26
  Speaker 1: and you could maybe make it. But now you've got
• 37:28
  Speaker 1: problems with well, do you have enough doctors and enough
• 37:30
  Speaker 1: engineers and enough people to work the farm. So there's
• 37:33
  Speaker 1: a lot of reasons why going big has a lot
• 37:36
  Speaker 1: of benefits.
• 37:37
  Speaker 2: I think it's funding the mental image of that of
• 37:39
  Speaker 2: freeze dried sperm. Why wouldn't you have them, you know,
• 37:42
  Speaker 2: like delicate test tubes, you know, imagining like you know,
• 37:45
  Speaker 2: liquid nitrogen flowing over them and something. Instead your words
• 37:49
  Speaker 2: give me a mental image of like a barrel of
• 37:51
  Speaker 2: the stuff.
• 37:52
  Speaker 1: You started this guy theme, and I was just kind
• 37:54
  Speaker 1: of running with it. But you're right, they'll probably be
• 37:56
  Speaker 1: in viles in a tube of liquid nitrogen or something
• 37:59
  Speaker 1: like that. Yeah, treat them better.
• 38:00
  Speaker 2: Delicately, clinking glasses and stuff like that.
• 38:03
  Speaker 1: That's right. Having technology to help with reproduction and bringing
• 38:07
  Speaker 1: along extra genetic diversity in the form of embryos, stuff
• 38:11
  Speaker 1: like this can really help with diversity problems. But again,
• 38:14
  Speaker 1: each generation you're going to have to deal with the
• 38:16
  Speaker 1: wants and desires of the humans who are there, who
• 38:18
  Speaker 1: are going to want to find partners that make them
• 38:20
  Speaker 1: feel complete, and who may or may not be comfortable
• 38:22
  Speaker 1: with being told, hey, your partner isn't as genetically diverse
• 38:26
  Speaker 1: as you might want. Sorry, this is what five generations
• 38:29
  Speaker 1: and an interstellarship does. So you are going to have
• 38:32
  Speaker 1: the embryo for which we provide fifty percent of the
• 38:35
  Speaker 1: genetic information, and not everybody is likely to love that.
• 38:38
  Speaker 1: And then what do you do when people get pregnant unintentionally?
• 38:42
  Speaker 2: Yeah, exactly. I think that's super fascinating and it touches
• 38:45
  Speaker 2: on another whole area of questions of like how you
• 38:47
  Speaker 2: manage the people on board, and what laws do you
• 38:49
  Speaker 2: have and what punishments can you do? Like you're shooting
• 38:52
  Speaker 2: people out the airlock if they're not being the right person.
• 38:54
  Speaker 2: It's crazy, But you know, on ships, the captains in
• 38:57
  Speaker 2: charge and for a reason. And so anyway, that's whole
• 39:00
  Speaker 2: other issue we could dig into another time of laws
• 39:02
  Speaker 2: on board interstellar trips. For now, let's take a break,
• 39:05
  Speaker 2: and when we come back, let's hear about a strategy
• 39:07
  Speaker 2: that might make that all moot. What if everybody just
• 39:09
  Speaker 2: sleeps their way to Alpha Centauri? All right, we're back,
• 39:29
  Speaker 2: and we are facing all the questions for taking humans
• 39:33
  Speaker 2: to another solar system. Radiation and gravity and greeding and
• 39:37
  Speaker 2: knowledge and all these things require keeping people awake, having
• 39:41
  Speaker 2: a functioning society on board, people sitting there munching on
• 39:44
  Speaker 2: their snacks and watching fast and furious. What if, Kelly,
• 39:47
  Speaker 2: we decide not to What if we just put everybody
• 39:50
  Speaker 2: out for the journey. What if we can freeze them
• 39:53
  Speaker 2: or hibernate them. You see this a lot in science fiction.
• 39:56
  Speaker 2: Is that realistic? Where is the technology now?
• 39:58
  Speaker 1: It's not realistic with current technology, But I wouldn't say
• 40:02
  Speaker 1: it's absolutely impossible. You can't just put everybody to sleep
• 40:06
  Speaker 1: as sleep is technically defined, because while you're sleeping, you
• 40:09
  Speaker 1: still have metabolic processes happening. You're still aging. So if
• 40:13
  Speaker 1: you were asleep, you'd still need to have like fluids
• 40:15
  Speaker 1: put in through an IV. You need to be fed.
• 40:17
  Speaker 1: Machines would have to roll you over. Sleeping wouldn't really
• 40:20
  Speaker 1: cut it.
• 40:20
  Speaker 2: It'd be like a coma, and nobody wants to be
• 40:22
  Speaker 2: in a coma for eighty thousand years, and you can't
• 40:24
  Speaker 2: live that long even in a coma, right. It doesn't
• 40:26
  Speaker 2: extend your life to sleep.
• 40:27
  Speaker 1: Right exactly. That's a total nonstarter. The next step up
• 40:30
  Speaker 1: from that would be hibernation. And so hibernation you have
• 40:34
  Speaker 1: a reduced temperature, you still have some metabolic stuff happening,
• 40:37
  Speaker 1: but the metabolic activity is way down, so like your
• 40:41
  Speaker 1: caloric needs go way down, you need less you're using
• 40:44
  Speaker 1: the restroom less stuff like that. And there's lots of
• 40:47
  Speaker 1: animals that hibernate. You know, You've got bear, squirrels, marmots,
• 40:50
  Speaker 1: prairie dogs, crowned hogs. Hibernation happens a lot, but it's
• 40:54
  Speaker 1: worth noting that one hibernation doesn't keep these animals alive forever,
• 40:58
  Speaker 1: and sometimes animals die well hibernating, so it's not like
• 41:01
  Speaker 1: you're one hundred percent safe when you go into a
• 41:03
  Speaker 1: hibernation state.
• 41:05
  Speaker 2: And can every animal hibernate? I mean bears and squirrels,
• 41:07
  Speaker 2: they do these things themselves, but like I've never hibernated.
• 41:10
  Speaker 2: Do humans hibernate?
• 41:11
  Speaker 1: I would like to hibernate sometimes when it's too cold out,
• 41:14
  Speaker 1: but no, humans do not hibernate. It's not clear how
• 41:18
  Speaker 1: we would put humans into a hibernation like state. It's
• 41:21
  Speaker 1: tantalizing that other mammals can do it, but it doesn't
• 41:24
  Speaker 1: necessarily mean that if we learned the right tricks, humans
• 41:27
  Speaker 1: could do it too. Humans do sometimes survive being very cold,
• 41:31
  Speaker 1: so like in a very hypothermic state, and every once
• 41:34
  Speaker 1: in a while if people have particular problems. So I've
• 41:36
  Speaker 1: read about somebody who had rabies, and they were trying
• 41:38
  Speaker 1: to slow down the movement of rabies and give the
• 41:41
  Speaker 1: body some time to respond in the vaccine, some time
• 41:44
  Speaker 1: to work. And so they essentially put the person in
• 41:46
  Speaker 1: a very cold state to slow things down. And people
• 41:50
  Speaker 1: can survive, but it's not like it's great for the body,
• 41:53
  Speaker 1: and it's not like it's extending their lifetime. So you
• 41:56
  Speaker 1: would still end up with people dying in a hibernation state.
• 42:00
  Speaker 2: Probably all right, So we can't just knock people out
• 42:03
  Speaker 2: with nik will. We can't just turn down the temperature
• 42:07
  Speaker 2: a little bit so people get cold and hibernate. What
• 42:10
  Speaker 2: if we go even colder? What if we like dip
• 42:13
  Speaker 2: everyone in liquid helium and turn them into humansicles? Will
• 42:17
  Speaker 2: that help? Is that possible? I mean, you hear about
• 42:19
  Speaker 2: this all the time on science fiction and on the
• 42:22
  Speaker 2: Simpsons for example, or Futurama. I forget which one it is.
• 42:25
  Speaker 2: But is this just fictional nonsense or is the science
• 42:28
  Speaker 2: moving us in that direction?
• 42:29
  Speaker 1: Scientists are trying to move us in that direction, some
• 42:33
  Speaker 1: of them are. So there have been people who very
• 42:35
  Speaker 1: soon after they passed away, had their body cryogenically frozen
• 42:39
  Speaker 1: in the hopes that at some point will figure out
• 42:42
  Speaker 1: the cure for their disease, or figure out some way
• 42:44
  Speaker 1: to sort of wake them back up again, or figure
• 42:46
  Speaker 1: out some way to upload their brain to a computer
• 42:49
  Speaker 1: once we really understand brains, so that their consciousness or
• 42:52
  Speaker 1: something can be brought back to life.
• 42:54
  Speaker 2: Right, they freeze them after they die. Don't you need
• 42:57
  Speaker 2: to freeze them before they die, otherwise you're just thawing
• 42:59
  Speaker 2: a core.
• 43:00
  Speaker 1: I was under the impression that for ethical purposes, you
• 43:03
  Speaker 1: do it like as soon as they're dead, and then
• 43:06
  Speaker 1: hope you can find some way to get everything moving
• 43:08
  Speaker 1: again to undead them. I mean, you know, people's like
• 43:11
  Speaker 1: heart stops. You could say they're dead, but you can
• 43:14
  Speaker 1: get them kicking again as long as you do it quickly.
• 43:16
  Speaker 2: Interesting.
• 43:17
  Speaker 1: I think that's the plant. But you know, if anybody
• 43:18
  Speaker 1: has like frozen people and want to tell us about it,
• 43:22
  Speaker 1: we'd love more information.
• 43:23
  Speaker 2: But it's call us at FBI dot gov.
• 43:26
  Speaker 1: That's right, that's right. Yes, I'm hoping that you had
• 43:29
  Speaker 1: permission and signed waivers and stuff first.
• 43:31
  Speaker 2: All right, but before we try this on humans, I
• 43:33
  Speaker 2: imagine we're going to test this onlike frogs or kittens
• 43:36
  Speaker 2: or something. How is that progressing?
• 43:38
  Speaker 1: Well, So, there are some animals that freeze naturally. So,
• 43:41
  Speaker 1: for example, there are some frogs in cold climates that
• 43:44
  Speaker 1: have something like anti freezing their blood. So the way
• 43:47
  Speaker 1: anti freezing your car works is it lets things get
• 43:49
  Speaker 1: a little bit colder without actually freezing. I think that
• 43:52
  Speaker 1: there's some combination of that happening and the cells also
• 43:56
  Speaker 1: using some additional mechanisms to make them robust to avoid
• 44:00
  Speaker 1: burst as water expands.
• 44:01
  Speaker 2: Yeah, I think that is what's happening. I think for
• 44:03
  Speaker 2: frogs what's happening also is that, like they're producing some
• 44:06
  Speaker 2: substances and a freeze you say, which maybe prevents ice
• 44:09
  Speaker 2: crystals from forming, and so like basically, if you dope
• 44:12
  Speaker 2: water with this stuff, then its chemical properties change. And
• 44:15
  Speaker 2: I think it's so incredible that water has this bizarre
• 44:18
  Speaker 2: behavior that when it freezes, it gets larger. It's very unusual, right,
• 44:21
  Speaker 2: most things, when you freeze them, they get smaller. But
• 44:24
  Speaker 2: the fact that ice is less dense than water means fish,
• 44:27
  Speaker 2: for example, can survive in the lake right because the
• 44:29
  Speaker 2: ice is on the top rather than on the bottom.
• 44:31
  Speaker 2: But also means that if you freeze, you explode, So
• 44:34
  Speaker 2: it's this funny double edged sword of chemistry.
• 44:37
  Speaker 1: Well, I believe there are some fish in Antarctica who
• 44:39
  Speaker 1: can survive freezing also if they end up in that
• 44:41
  Speaker 1: like frozen layer of ice. So the point is there's
• 44:44
  Speaker 1: a variety of animals that can survive freezing, and while
• 44:48
  Speaker 1: humans at this point cannot survive freezing, maybe there's some
• 44:51
  Speaker 1: lessons that we can learn from these animals or from
• 44:54
  Speaker 1: Tartar grades, to try to figure out a way where
• 44:56
  Speaker 1: we could cryogenically preserve life people thaw them out and
• 45:00
  Speaker 1: bring them back to life. But it's worth noting that,
• 45:03
  Speaker 1: as far as I know, there's never been a frog,
• 45:07
  Speaker 1: for example, that was frozen for ten thousand years and
• 45:10
  Speaker 1: then brought back to life. You know, like we talked
• 45:13
  Speaker 1: about some tartar grades that managed to be frozen for
• 45:15
  Speaker 1: a very long time, but I think you know, when
• 45:18
  Speaker 1: you get to vertebrate level, it's even harder to survive
• 45:20
  Speaker 1: freezing for a very long time. So it's not clear
• 45:23
  Speaker 1: that cryogenics will be compatible with the human body, or
• 45:27
  Speaker 1: that it will be compatible with the human body on
• 45:29
  Speaker 1: the time scales needed to get to alpha centauri.
• 45:31
  Speaker 2: It's too bad we don't have the biological technology of plants.
• 45:34
  Speaker 2: You know, seeds are incredible. I read stories where they
• 45:37
  Speaker 2: like dug up ancient seeds and like planted them and
• 45:39
  Speaker 2: gave them water and they sprouted, and there's like, oh,
• 45:41
  Speaker 2: here's a date palm whose parent grew like thousands of
• 45:45
  Speaker 2: years ago and it just sat there it totally shelf
• 45:48
  Speaker 2: stable for thousands of years. It's incredible biological technology. It's
• 45:52
  Speaker 2: too bad we don't have seeds.
• 45:54
  Speaker 4: You know.
• 45:54
  Speaker 1: Trees make no sense to me. My husband has been
• 45:57
  Speaker 1: gardening lately and he'll say things to me about like, oh, well,
• 45:59
  Speaker 1: you can just cut that branch off and put it
• 46:01
  Speaker 1: in the soil and you'll get a new tree. And
• 46:02
  Speaker 1: I'm like, that's not how life works. You can't do
• 46:05
  Speaker 1: that to me. But it works with trees.
• 46:08
  Speaker 2: I know. I remember saying to him, like, why can't
• 46:10
  Speaker 2: I just stick my arm in the ground and grow
• 46:11
  Speaker 2: a new person?
• 46:12
  Speaker 1: That's right, Yeah, trees are wild. And so some of
• 46:16
  Speaker 1: the most sci fi ish plans I've come across involve
• 46:19
  Speaker 1: things like having an artificial womb with freeze dried embryos
• 46:24
  Speaker 1: that you send.
• 46:24
  Speaker 2: With you because embryos we can freeze and revive.
• 46:27
  Speaker 7: Right.
• 46:27
  Speaker 2: That's amazing.
• 46:28
  Speaker 1: It is amazing. Yeah, and so I don't know that
• 46:30
  Speaker 1: you can freeze them for eighty thousand years for the
• 46:33
  Speaker 1: trip to Alpha Centauri, but you know, if you get
• 46:35
  Speaker 1: there faster, and you can probably move much faster if
• 46:37
  Speaker 1: you don't have squishy humans on board to worry about.
• 46:39
  Speaker 2: Some of my best friends have two kids, and both
• 46:41
  Speaker 2: of them came from frozen embryos. One kid is two
• 46:44
  Speaker 2: years older, but they're actually the same age. It's just
• 46:47
  Speaker 2: that one of them has been unfrozen for two more years.
• 46:50
  Speaker 2: And I think about that every time I see these brothers.
• 46:52
  Speaker 2: I'm like, you guys are actually the same age. Just
• 46:55
  Speaker 2: one of you was frozen for two years.
• 46:57
  Speaker 1: That is amazing. Reproductive technology is incredible, the things that
• 47:01
  Speaker 1: we're able to do.
• 47:01
  Speaker 2: Yeah, so you're going to put this in the maybe
• 47:04
  Speaker 2: category that we potentially could develop cryogenic technology that could
• 47:08
  Speaker 2: freeze humans and unfreeze them after thousands of years. It's
• 47:12
  Speaker 2: not clear how we would do it now, but you're
• 47:13
  Speaker 2: not going to say it's impossible.
• 47:14
  Speaker 1: I'm going to put the cryogenic humans on the fairly
• 47:17
  Speaker 1: unlikely Oh no, for the time frames necessary to get
• 47:21
  Speaker 1: to Alpha Center. If you could get one of those
• 47:24
  Speaker 1: propulsion techniques to get you there in like five years,
• 47:27
  Speaker 1: and you just had to freeze people so they didn't
• 47:29
  Speaker 1: get bored during the trip. Then maybe you could get
• 47:31
  Speaker 1: away with that. But when you think about what else
• 47:34
  Speaker 1: humans would need when you wake them up, it starts
• 47:36
  Speaker 1: getting complicated. So you know, if those humans ever want
• 47:39
  Speaker 1: to have a fresh egg, you also need to figure
• 47:41
  Speaker 1: out a way to get the chickens going. You know,
• 47:43
  Speaker 1: you also need to store the food for them. Like
• 47:45
  Speaker 1: it gets incredibly complicated. But you know, maybe you could
• 47:49
  Speaker 1: just bring a bunch of genetic material with you and
• 47:51
  Speaker 1: have a lot of robots that start planting the farm.
• 47:54
  Speaker 1: You know, a couple months before the humans are going
• 47:56
  Speaker 1: to be gestated in the artificial womb, but now was
• 48:00
  Speaker 1: going to raise them. Like, as a parent, it is
• 48:02
  Speaker 1: amazing to me how much work it takes to get
• 48:06
  Speaker 1: children to like just shower or brush their teeth. Like,
• 48:09
  Speaker 1: there's so much nagging that needs to happen.
• 48:12
  Speaker 2: You're out in the crowd and you look at all
• 48:14
  Speaker 2: those people and you're like, wow, all these people were
• 48:16
  Speaker 2: raised some parents like taught these humans how to survive
• 48:19
  Speaker 2: and exist in a crowd, and like be functional, Like,
• 48:22
  Speaker 2: that's so much work.
• 48:23
  Speaker 1: Wow, it is. Yeah, culture is incredible. The fact that
• 48:26
  Speaker 1: we've managed to get ourselves here by like policing each
• 48:29
  Speaker 1: other's behaviors is fantastic.
• 48:33
  Speaker 2: All right. Well, I see you struggling to not be
• 48:35
  Speaker 2: the negative nelly and do not want to say no,
• 48:38
  Speaker 2: it's impossible, but it seems like, yeah, pretty implausible.
• 48:41
  Speaker 1: I would say within my lifetime, not gonna happen, right,
• 48:44
  Speaker 1: But science often has breakthroughs that surprise me, and in
• 48:48
  Speaker 1: a couple of lifetimes maybe it would happen.
• 48:50
  Speaker 2: But the embryos and parental robots thing, that's a cultural issue, right.
• 48:54
  Speaker 2: We think that technologically that might actually be possible. I mean,
• 48:58
  Speaker 2: you might get weird humans that might kill all each other,
• 49:00
  Speaker 2: or they might like launch nukes back at us or something.
• 49:03
  Speaker 2: But in terms of like getting people to the other
• 49:06
  Speaker 2: planet and growing them there, that could work.
• 49:08
  Speaker 1: Right, It's possible that it could work. I mean, I
• 49:11
  Speaker 1: think there's a lot of things we don't understand very well.
• 49:13
  Speaker 1: So for example, when babies are born through a mother's body,
• 49:17
  Speaker 1: they get slathered in bacteria that are important for the
• 49:19
  Speaker 1: way their bodies work. They get food to the bacteria
• 49:22
  Speaker 1: in their guts from breast milk. I think we don't
• 49:24
  Speaker 1: really understand what would happen to humans if they were
• 49:27
  Speaker 1: raised by robots and only encountered other babies of a
• 49:31
  Speaker 1: similar age or other people of a similar age. But
• 49:33
  Speaker 1: somebody should write a sci fi novel about that.
• 49:35
  Speaker 2: Or we should just do it and see what happens.
• 49:38
  Speaker 1: Yeah, that sounds totally ethical, totally all right.
• 49:43
  Speaker 2: So it sounds like there's a lot of challenges to
• 49:45
  Speaker 2: getting humans from here to Alpha Centauri. Even if you
• 49:47
  Speaker 2: solved all the physics problems we raised in the last episode,
• 49:50
  Speaker 2: there are a lot of biological problems, a lot of
• 49:52
  Speaker 2: cultural problems, a lot of technological problems to solve getting
• 49:55
  Speaker 2: the humans there safely.
• 49:57
  Speaker 1: Yes, and we didn't touch on a lot of the society,
• 49:59
  Speaker 1: the all the ethical problems. There's a lot more stuff
• 50:01
  Speaker 1: we could talk about. And also I recommend ed Regis's
• 50:05
  Speaker 1: book Starbound, which is all about interstellar travel and some
• 50:07
  Speaker 1: of the challenges that you encounter along the way. That
• 50:10
  Speaker 1: was an interesting read.
• 50:11
  Speaker 2: So if somebody wants to sell you a ticket to
• 50:13
  Speaker 2: Alpha Centauri, we're going to officially recommend maybe.
• 50:16
  Speaker 1: Maybe yeah, I would not buy that ticket, but I'm
• 50:20
  Speaker 1: sure other people would, and I'm sure it would be
• 50:22
  Speaker 1: an amazing experience.
• 50:23
  Speaker 2: Yeah, and I hope you enjoy Fast and Furious Number
• 50:25
  Speaker 2: seven hundred and forty two on your trip.
• 50:28
  Speaker 1: Enjoy. Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio.
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