Can humans survive interstellar travel?

Daniel and Kelly talk about how to keep humans healthy and happy during interstellar voyages. See omnystudio.com/listener https://omnystudio.com/listener for privacy information.

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

• 0:00Speaker 00

  This is an iHeart Podcast. Guaranteed Human. Running a small business takes everything you've got. But with Chase for Business, you're not alone. They bring together local support and a broad range of resources to more than 7 million customers. With a deep understanding of your day-to-day needs, they provide products and guidance built to help you thrive. Right now, earn $500 when you open a new Chase Business Complete Checking account for new business checking customers with qualifying activities. Offer expires January 21, 2027. Chase Business Complete Checking has the flexible tools you need to accept payments, make deposits, and manage your finances with confidence.

• 0:43Speaker 00

  Learn more at chase.com/podcastbizoffer. Chase: Make more of what's yours. Fees may apply to Chase Business Complete Checking accounts. The $500 offer is available for new business checking accounts with qualifying activities through January 21, 2027. Eligibility and qualification requirements must be met. Additional restrictions may apply. Please speak with a business banker for more information. JPMorgan Chase Bank, N.A., Member FDIC.

• 1:18Kelly Weinersmith?

  Imagine a future 100, maybe 200 years from now. In-space manufacturing has come a long way, and we can now build colossal structures using resources collected from the moon and the asteroids. First interstellar ship has been built and is getting loaded up with supplies for a long trip to Alpha Centauri. It's now time to pick the crew who will be the ambassadors for humanity should we meet intelligent life in the neighboring solar system. How many people will we send? How should we pick them? What dangers will they face en route? And what will their lives be like during this journey? In our last episode, we talked about the rockets that could carry us to distant stars.

• 1:59Kelly Weinersmith?

  Today, we're going to talk about the squishier side of things, focusing on some of the human stuff you'd have to deal with on an interstellar journey. Welcome to Daniel and Kelly's Extraordinary Universe.

• 2:24Daniel Whiteson?

  Hi, I'm Daniel. I'm a particle physicist and the longest flight I've ever taken was 14 hours.

• 2:31Kelly Weinersmith?

  Hi, I'm Kelly Weiner-Smith. I study parasites in space and I think the longest flight I've taken was 12. I've been down to Brazil. I haven't really kept track of how long my flights were. Where were you going?

• 2:42Daniel Whiteson?

  I went to an absolutely ridiculous slash amazing boondoggle conference in Fiji on the island of Morea, where the University of California has a research station. And we were there to talk about dark matter, of course. So I brought my daughter and we did a lot of snorkeling and hiking and we rode horseback up the mountains and tried to keep the horses from eating pineapple plants. And it was an amazing time, but wow, the flight was long.

• 3:07Kelly Weinersmith?

  What made it a boondoggle?

• 3:08Daniel Whiteson?

  Why do you need to go to a tropical island to talk about dark matter? You don't. That's what makes it a boondoggle.

• 3:15Kelly Weinersmith?

  Yeah. I gotta be honest, ecology has a lot of that, too. It's like, why do you need to go to the glorious rainforest to answer questions about frogs when you've got frogs in the US? But I get it. We like going to beautiful places.

• 3:27Daniel Whiteson?

  Yeah, it's one of the perks of being a scientist is getting to travel to weird, random places to meet with your colleagues.

• 3:33Kelly Weinersmith?

  That's true. That's true. I love getting to see new places. I often get invited to places that I never actually really wanted to go to. But once I get invited, I'm like, yeah, I want to go to Slovakia. And I love Slovakia. Bratislava was beautiful.

• 3:46Daniel Whiteson?

  Well, what's your experience like on these long flights? Because I always feel like, oh, 14 hours, no big deal. I'll just watch a few movies. And then like, two movies in, I'm like, wow, get me off this plane. And then like, four movies in, I'm gonna kill myself. And then by the time I land, I'm like, hmm, that wasn't so bad.

• 4:05Kelly Weinersmith?

  I hate it. I have a very similar experience. I can't sleep. I try to sleep. I can't sleep. I'm not comfortable. Every once in a while, I'll get lucky and there'll be no one else in the row and I can just like, lay down. And at least then I feel kind of rest-ish, or restoid.

• 4:22Kelly Weinersmith?

  I know, I hate it too. And then I always feel kind of angry at the people in first class because they've got like a much nicer setup. But you know, what are you gonna do?

• 4:31Daniel Whiteson?

  You're not going to spend $10,000 for that flight. That's

• 4:33Kelly Weinersmith?

  Heck, no!

• 4:35Daniel Whiteson?

  That doesn't seem worth it. Yeah.

• 4:35Kelly Weinersmith?

  Nope.

• 4:36Daniel Whiteson?

  But if I was an astronaut and I was going to the moon, or to Mars, or to Alpha Centauri, I might want the engineers to build in a seat that can fully recline. What do you think?

• 4:46Kelly Weinersmith?

  Heck, yes. You do have to have a completely different mindset to really enjoy super long trips. Like Jim Lovell and Frank Borman were on a Gemini trip around the Earth. And I think they were up there for something like two weeks. And it was a really tiny space. And at least on airplanes, like, yeah, the bathroom is small. It's super inconvenient. I hate it. But it's got a door. And the Gemini didn't. And so Frank Borman tried to go all 12 days without having a bowel movement. And I think he made it like eight days or something. And then he was like, Jim, I can't wait anymore.

• 5:18Daniel Whiteson?

  I'm about to make a delivery.

• 5:20Kelly Weinersmith?

  Oh, gosh. Yeah. So anyway, it could be worse.

• 5:23Daniel Whiteson?

  So you're saying that the cutting edge, super distant travel is less convenient and less comfortable than like, economy flights across the country? That doesn't make any sense to me.

• 5:31Kelly Weinersmith?

  Well, you know, you've got to pay for all of the space that you send up there. And it's super expensive. And I mean, let's be honest, anybody who's told you get to go to space is going to put up with whatever you give them. And so they're definitely going to go. But there was a recent SpaceX trip where there were complaints about the bathroom also. And I think it was the Dragon capsule. Restrooms in space are just hard to pull off well.

• 5:51Daniel Whiteson?

  I think this is another case of like, my over optimistic rose colored glasses when it comes to space travel, imagining that the problems we have with like, airplane flights are not going to be even worse on space trips. They're somehow all going to be comfortable and get along. And the food is going to be amazing, like it is on Star Trek, right? That's why I was excited that today, we're going to dig into like, the reality of a potential interstellar trip. What's it gonna be like? Will there be doors on the bathrooms? How far back will the seats recline? And will they have anything besides peanuts and pretzels?

• 6:22Kelly Weinersmith?

  Well, let's dig in and find out. So this is part two of our interstellar travel series. We talked about the kinds of rockets that get you to space in the last episode. And today, we're talking about the squishy human side of things. And so we asked our listeners, can humans survive interstellar travel? Why? Or why not? Here's what they had to say.

• 6:42Speaker 03

  Humans could survive interstellar travel with terraform spaceships and over multiple generations they could get somewhere interesting.

• 6:52Speaker 04

  There are so many unknown issues with closed ecosystems in order to produce the food that we need in the form of plants, etc., that I'm not too sure that we've solved all the problems necessary in order to have a long-duration interstellar travel.

• 7:10Speaker 05

  With our current technology, I don't think it's possible, but maybe with advances in propulsion and radiation shielding and artificial gravity from propulsion, that might be possible.

• 7:23Speaker 06

  One human couldn't survive because we haven't sorted suspended animation yet. But if you're talking about generations of humans, assuming we've sorted all the problems of sustaining reproduction and nutrition and health, I wonder whether the risks of the dangers posed by cosmic rays will actually be less in deep space. We'd only then have to worry about the problem of re-entry into the new stellar system.

• 7:53Speaker 07

  I think generally it's possible, but you have the problem that when you go fast, you have cosmic rays that are really high energy, and if you go slow, it takes forever. So it's a trade-off and you lose in both situations.

• 8:06Speaker 08

  It depends on how far away the other star is. If the star we're trying to get to is the one that we're going to share OAR clouds with in about a million years or so, then that's much more achievable than a star on the other side of our galaxy.

• 8:19Speaker 09

  I say no because the first humans who leave Earth going to interstellar space will not be alive because it takes approximately 22,000 to 25,000 years to exit our solar system. And that opens up the question about children in space to continue the journey because the adults who begin the journey will not live to exit our solar system, so no.

• 8:36Speaker 10

  If we allow for human reproduction en route, which is a big if, humans would encounter significant survival challenges, not the least of which is that our physiology is ill-equipped to handle zero-gravity and excessive radiation exposure. And in the vein of "we do not know what we do not know," there are likely other factors that terrestrial living either provides for us or protects us from that we would fatale and tragically encounter on the interstellar voyage.

• 9:00Speaker 11

  We can imagine traveling to other solar systems, but can we deal with all the questions? Radiation, food, power sources, generation ships?

• 9:11Speaker 11

  We just don't know enough at this point.

• 9:13Daniel Whiteson?

  Those are super fun answers. And if you find yourself speaking back to the podcast with your own answers, then send us those answers and we'll put them on the pod so that everyone else can hear what you have to say. Just write to us to questions at danielandkelly.org and we will share your insights with the world.

• 9:30Kelly Weinersmith?

  Looking forward to hearing from you. And we've been very excited to have more women sharing their responses lately. So let's keep that up. Go women.

• 9:37Daniel Whiteson?

  Well, do you think our listeners also have rose colored glasses and they're underestimating the difficulty of traveling to space? Or do you think they have a realistic sense?

• 9:46Kelly Weinersmith?

  We have a really nice range of people who are super optimistic and I would maybe say not quite reasonably so. And then people who are maybe a bit more down on the enterprise than is necessary. We've got a lot of variability. I think it depends a lot on the timeframe that you're willing to consider for this question.

• 10:03Daniel Whiteson?

  All right. Well, let's dig into the problem. Why space travel is so much harder than airplane trips, or if it's just airplane trips times a thousand. Tell us what basically are the obstacles here to traveling in safety and comfort to another solar system?

• 10:18Kelly Weinersmith?

  Well, as you pointed out in the last episode, space is vast. And so if we're going to Alpha Centauri, that is four light years away. So with current technologies, we're talking about 80,000 years. That's a lot of human generations.

• 10:31Daniel Whiteson?

  That's a lot of movies to watch. Wow.

• 10:33Kelly Weinersmith?

  Oh, my gosh. Yeah. Maybe in the next hundred years, Marvel will make enough movies to get you to Alpha Centauri.

• 10:39Daniel Whiteson?

  I think there might be enough Fast and Furious movies to make it. I'm not sure.

• 10:43Kelly Weinersmith?

  I would not make it to Alpha Centauri on Fast and Furious movies. I would rather push myself out the airlock, but all right.

• 10:49Daniel Whiteson?

  No, you're missing out. You're missing out. Fast and Furious is fantastic because they don't take themselves seriously. Like every movie, they have even more ridiculous stunt. They're like, oh yeah, how about a space shuttle? Okay. How about a submarine on the ice with a torpedo? It's ridiculous and fantastic and really creative. I watch a lot of terrible movies and there's always something new in the Fast and Furious that makes me go, whoa, that was cool. So yeah, don't overlook them.

• 11:15Kelly Weinersmith?

  Okay. All right. I'll take another look at the Fast and Furious series. I didn't imagine I would say that phrase today, but there you go.

• 11:20Daniel Whiteson?

  But I don't think we want to travel the stars fast and furious. I think it's going to be more like slow and calm is the way to go.

• 11:25Kelly Weinersmith?

  That's what I would like, and with no explosions or anything like that. So you said that we could get to Alpha Centauri in 40 years if you can travel at 10% the speed of light.

• 11:34Daniel Whiteson?

  Yeah.

• 11:34Kelly Weinersmith?

  So we're going to talk about a range of different options. What if you could get there fast if the technology works out? And what if you need to get there over the course of multiple generations? So you need to have a generational ship, sometimes called an ark. And this field has a good sense of humor. So sometimes they call the study archaeology.

• 11:53Daniel Whiteson?

  Awesome.

• 11:55Kelly Weinersmith?

  Which I love.

• 11:56Daniel Whiteson?

  That is very cool.

• 11:57Kelly Weinersmith?

  All right. So one human thing we're going to need to overcome is this whole money situation, because the cost of a project like this is probably going to be massively prohibitive. So you talked about how much mass would be needed to hold the propellant and that for chemical rockets, the tank would have to be as big as Jupiter.

• 12:15Daniel Whiteson?

  Yeah. And then you also need to somehow find that fuel.

• 12:18Kelly Weinersmith?

  Yeah, right.

• 12:18Daniel Whiteson?

  Basically, you have to use Jupiter as your rocket. Yeah.

• 12:20Kelly Weinersmith?

  Many layers of problems here. But you know, if you're talking about bringing humans that are awake, you're also going to need space for recreation areas, space for schooling, space for medical facilities, places to grow food. The International Space Station is the most expensive human made object ever, and it's clocking in at about $150 billion. And it usually holds seven people uncomfortably.

• 12:43Daniel Whiteson?

  So this is going to cost a lot of money, but we're basically just going to ignore the financial side of the question?

• 12:47Kelly Weinersmith?

  We are. Yes. Right. So let's assume that money is no longer an object.

• 12:51Daniel Whiteson?

  Yay.

• 12:51Kelly Weinersmith?

  Yay. That's right. Humanity has decided we absolutely must do this.

• 12:55Daniel Whiteson?

  Okay.

• 12:56Kelly Weinersmith?

  What kind of problems are the humans going to encounter? As you might remember from our conversations on Mars and the moon, space has a lot of radiation that is bad for humans. It has two kinds of radiation that are not very common here on Earth, and that's galactic cosmic radiation and solar particle events. And these are bad for equipment and for people. And I'm kicking over to Daniel. Tell us about galactic cosmic radiation and solar particle events.

• 13:22Daniel Whiteson?

  Yeah, so the sun puts out a lot of light, but it also shoots out a lot of other stuff. You know, their protons, their electrons. Basically, it's just spewing plasma. We call this the solar wind and it's moving at high speed. So these particles are dangerous because any one of them hits your body, tears through it like a little tiny bullet. It can rip apart DNA, it can destroy cells. It's not good. One random one, you're probably fine, but you take enough of these, you're getting cancer. And down here on the surface of the earth, we don't worry about this because while the solar wind is hitting the earth, the atmosphere protects us. It's an enormous, very thick, very massive blanket. And the whole idea is that when you go out into space, you no longer have that atmosphere. So you have to replicate that with shielding. Galactic cosmic rays are a whole other question.

• 14:07Daniel Whiteson?

  They're basically radiation from other stuff in the galaxy, like the combined radiation from other stars and from black holes and from other weird stuff we've never even figured out. Like there are particles that are so high energy, there's nothing in the universe we know of that can make particles go that fast and yet we see them. So there's like really fascinating physics mysteries there. But from a human survival point of view, you don't want these super duper high energy particles hitting you. Basically, space is filled with tiny bullets and you gotta go up there with a bulletproof vest.

• 14:37Kelly Weinersmith?

  I am always so impressed by how eloquent you are when I put you on the spot. Bravo. So we're gonna need to shield against this kind of stuff. And it's not just a problem for human bodies. It's also a problem for our machines. Did I tell the story on the show before about Terry Wertz and Samantha Kristofaretti when the ISS had a false alarm?

• 14:54Daniel Whiteson?

  Oh, tell us.

• 14:55Kelly Weinersmith?

  All right, so you've got Terry and Samantha in space on the International Space Station and an alarm starts going off. And Terry's not immediately sure what this alarm means, but Samantha has memorized all the alarms and it's an ammonia leak. And on the US side, ammonia is used to cool the space station, but ammonia is also toxic. So the protocol for what you do when there's an ammonia leak is you run over to the Russian side, you close the first hatch, you take off your clothes, you close the second hatch with you on the other side.

• 15:25Daniel Whiteson?

  Take off your clothes? Why do you have to take off your clothes? Does this make it more fun and dramatic?

• 15:30Kelly Weinersmith?

  Well, yeah, I mean, one. Sure, but also that ammonia could cling to your clothes and you don't want to bring it over to the Russian side. So you gotta hope the Russians have some undies they'll be willing to loan you. And so they ran over, they closed the first hatch, but they didn't smell the ammonia. And this is an important sort of lesson about how humans respond. Like, it sort of doesn't matter what protocols you put into place. When one human is looking at another human and they're both like, "Am I gonna really see you naked right now?" They decided to just skip that step and they went in with all of their clothes over to the Russian module.

• 16:01Daniel Whiteson?

  Interesting.

• 16:02Kelly Weinersmith?

  It did turn out it was a false alarm. And the reason you go to the Russian module is because they use glycol to cool their side, which is not as toxic. And so if the leak was coming from anywhere, it was the US side. Anyway, it was later determined that the most likely reason that this alarm got switched on was because the computer had been hit with galactic cosmic radiation, which messed with the equipment and started setting off alarms. You could have cancer, cognitive declines, your machines could start breaking down. So this is a problem we need to take seriously.

• 16:30Daniel Whiteson?

  Yeah, this is actually really fascinating from an engineering point of view. You know, what's happening is that these particles are passing through your equipment. Sensitive bits of it are mostly made out of silicon. And when a high-energy particle passes through, it leaves a trail of ions. You know, it like kicks electrons and leaves holes. And this is how these things work also, right? They like separate the holes and the electrons. And so all of this equipment can get like a false bit. Like you can have a zero in your memory and then it can turn into a one or something. And so these kind of cosmic ray bit flips are a real concern. And like massive data centers worry about this also, but they have a lot of error correction. And so they have like duplications and cross-checking to basically remove this. So you can either have a lot of duplication or you can try to make it radiation hard by shielding it.

• 17:14Daniel Whiteson?

  They even folks who are using diamonds instead of silicon, because diamond has a lot of the same electrical properties, but it's radiation hard. You can grow diamond, it's much more expensive and there's not a huge industry for this. But like at the Large Hadron Collider, there's very intense radiation near all of our sensitive detectors. So every couple of years, we gotta pull it out and swap in a new one because it's basically ruined.

• 17:35Kelly Weinersmith?

  Wow.

• 17:36Daniel Whiteson?

  So yeah, electronics are very sensitive to high levels of radiation. And if you are relying on your electronics to keep you alive in an 80,000-year journey in all of your grandkids and great-grandkids, then yeah, you want those things to work.

• 17:48Kelly Weinersmith?

  Yeah. And so the shielding could come in the form of things like water, like you could store your water supply on the outside. Would that help with galactic cosmic radiation too, Daniel?

• 17:57Daniel Whiteson?

  Yeah, with various kinds of it. Yeah.

• 17:59Kelly Weinersmith?

  Okay.

• 17:59Daniel Whiteson?

  But mostly, you basically just need high Z mass. Like you need atoms with a lot of protons and neutrons between you and the radiation.

• 18:07Kelly Weinersmith?

  Got it. I've also seen proposals for scraping the regolith off the moon and padding your interstellar ship with it. That would be complicated, but it's a solution.

• 18:16Daniel Whiteson?

  That would be pretty cool because then your ship looks like a rock, you know?

• 18:19Kelly Weinersmith?

  Yeah.

• 18:19Daniel Whiteson?

  It's like floating through space like masquerading as an asteroid or something.

• 18:24Kelly Weinersmith?

  Mm hmm. Well, another complicated problem we're going to need to solve is what do you do about no gravity?

• 18:28Daniel Whiteson?

  Right. But the takeaway from the shielding is an important one, right? It makes our ship big and massive and heavy, and that makes it expensive, right? But fortunately, money is no hurdle for us. So, cool.

• 18:38Kelly Weinersmith?

  That's right. In space, manufacturing might help with this a lot. So, you know, you could, like I mentioned, go get the regolith from the surface of the moon, but also you could go to the asteroids and extract water from the asteroids. And that way you don't have to pay to boost it from Earth. But one way or another, it's going to be an expensive, massive project.

• 18:54Daniel Whiteson?

  Yeah. All right. So problem number one is radiation.

• 18:56Kelly Weinersmith?

  Yes. And problem number two is going to make the design of our vehicle even more complicated. And problem number two is that there's no gravity in deep space. So we know from astronauts on the International Space Station and the space stations that came before, that when they are essentially in free fall and feeling the equivalent of no gravity, that their bones start breaking down, their muscles start breaking down, and the gravity on Earth and the fact that we're constantly moving around and submitting our bones and muscles to gravity and then the pressure of our bodies as we run around, that makes our bones and muscles strong. That's like a cue our bodies need to keep these things toned. Without those cues, they just start to decay because you're not using them. So bodies start falling apart. Additionally, we see declines in vision, and we think that's

• 19:39Kelly Weinersmith?

  because the fluids in our bodies, without gravity to pull them down, sort of accumulate near our heads and change the shape of our eyes. There's also some evidence that there could be some cognitive declines. Basically, we're gonna want some gravity when we're living out our lives on a ship.

• 19:54Daniel Whiteson?

  And folks out there might be thinking, well, you know, we're adapted to life on Earth, but if we spend it long enough in space, maybe our bodies are just going to adapt. Maybe we don't need those bones and those muscles because hey, we're all floating around to the blue Danube anyway, right? Why do we care about degradation of our bones and our muscles if we're just floating in space?

• 20:12Kelly Weinersmith?

  Yeah, so that's a great question. We don't actually know that we could survive long term. So the longest anyone has ever been in space, I think, is 437 days. That was Valery Polyakov. So we don't even have like more than a year and a half of consecutive time in space. We know that astronauts lose something like 1% of the density of their hip bone per month. And we don't know if that tapers off eventually, but if you imagine trying to have babies in space.

• 20:39Daniel Whiteson?

  Hold on, wait, I'm gonna imagine it. Hold on. Mmm, oh yeah, that seems gooey.

• 20:42Kelly Weinersmith?

  Oh, yeah, that is such a guy response. The gooeyness is not a problem, man.

• 20:47Daniel Whiteson?

  But now you're in space, you have like weird balls of goo.

• 20:49Kelly Weinersmith?

  It's like, oh. Imagine trying to do a C-section in space with like the blood floating around your head. Anyway, unpleasant.

• 20:56Daniel Whiteson?

  Or imagine like a diaper explosion, you know, like loss of containment in space. I don't know about that.

• 21:00Kelly Weinersmith?

  Loss of containment.

• 21:03Daniel Whiteson?

  You've had that experience. You know what I'm talking about. We've all had the like transatlantic flight with loss of containment of the diaper like, ooh.

• 21:10Kelly Weinersmith?

  No, I did. Right when a plane was taking off, my daughter had a blowout on my lap and we couldn't get up for 30 minutes and oh, man, nobody liked me. And I brought a change of clothes for her, but not for me, but she sat on my lap. Anyway, all right. These problems only get more difficult in space. So we don't know, for example, that women's hips will be able to survive childbirth. And we just generally don't know if you can survive a lifetime, but maybe you can. So let's say that you can. Let's say that not only can you survive, but you can also go through reproduction in zero gravity, which again, I think is highly unlikely, but we don't have a lot of good science for that. There's a lot of reasons why you'd want at least a little bit of gravity and you know, a lot of them have to do with things like using the restroom. So we talked a little bit about how that's unpleasant at the start of the show.

• 21:54Daniel Whiteson?

  My gooey imagination is feeling of the details for me. Yes.

• 21:57Kelly Weinersmith?

  Oh, yeah. You're really into gooey today. It's only gonna go downhill from here. When I was researching a city on Mars, every space vehicle that I read about had a story about escapees, where the escapees were like bits of feces that kind of floated out. It's just hard to keep things clean. Everything is more of a pain in the rear end. If you have just a little bit of gravity, surgery gets easier, restrooms get easier, farming gets easier. We're almost certainly going to need at least a little bit of gravity just to like, hold our stuff down and make our lives easy.

• 22:28Daniel Whiteson?

  And if you hope that your descendants or whoever is arriving in the distant solar system is going to be able to get off the ship and walk around on this new alien planet, they're going to have to have some bones and muscles, right? So it makes sense to maintain that capacity on the trip.

• 22:41Kelly Weinersmith?

  Absolutely. So not only are we going to have this massive object, but this massive object needs to have at least some areas that are spinning to create artificial gravity so that you've got some of that force keeping your body strong or helping, you know, the brown trout swim down the river in the right direction.

• 22:57Daniel Whiteson?

  All right. So we've talked about radiation and that might be a solvable problem with enough shielding. And we talked about gravity might be a solvable problem if we have acceleration or something spinning or something like that. So so far, I'm feeling kind of optimistic about how our kids, kids, kids, kids, kids might be able to walk off the ship and stand on a planet around Elvis and Tari. So let's take a break. And when we come back, Kelly's going to tell us about how that's all an impossible dream.

• 23:23Kelly Weinersmith?

  I'm not trying to be negative today.

• 23:27Daniel Whiteson?

  The facts are working against you, though.

• 23:37Speaker 12

  Hey, it's Niall Rogers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything.

• 23:53Speaker 12

  This week, I'm joined by my friend, John Ledge. How does music actually enter your mind?

• 24:00Speaker 13

  I'm not sure why or how the music comes to me, but I think people who love music and write music, our brains are just filled with music.

• 24:09Speaker 12

  Right.

• 24:10Speaker 13

  Like, we have listened to so much music. We've been a part of so much music. I think of the story that I want to tell, the mood that I want to create with the music, start playing chords, see where they lead me.

• 24:21Speaker 12

  Sometimes, I'm just not even thinking about music, right? And I hear this little thing, and I go, oh, that could be this.

• 24:31Speaker 13

  You know, you just have to be ready for when the inspiration hits.

• 24:34Speaker 12

  It comes.

• 24:35Speaker 13

  Yeah.

• 24:35Speaker 12

  Experience before the moment. A Lincoln original series on the iHeart Radio app, YouTube, or wherever you get your podcasts.

• 24:44Speaker 14

  This is Hoda Kotb from Joy 101 with Hoda Kotb. Have you started your holiday shopping yet? This time of year always feels like the list just keeps growing. Gifts for family, gifts for friends, stocking stuffers, plus all the everyday things you still have to buy, like groceries and gas. That's why being a little strategic about the spending on gifts and those everyday needs is key. With the Chase Freedom Flex Card, you can be a little savvier. Finding the right gift feels good, and maximizing cash back feels even better. Freedom Flex offers plenty of ways to earn more. You get 5% cash back on popular rotating quarterly categories, 3% on dining and drugstores, and 1% on all other purchases.

• 25:27Speaker 14

  So while you're checking names off your holiday list, those gifts can be a treat for you, too. This holiday season, let Freedom Flex reward you. More ways to earn, more ways to get rewarded. So sign up for the Chase Freedom Flex Card. Learn more at chase.com/getflex. This is a paid collaboration with Chase Freedom Flex. Cards issued by JPMorgan Chase Bank, N.A. Member FDIC. Subject to credit approval. Offer subject to change. Terms apply.

• 25:56Speaker 15

  Right now, you can save 70% on SimpliSafe home security. When an intruder approaches a home, they expect a camera. What they don't expect.

• 26:04Speaker 16

  Stop. This is Simply Safe. You're being monitored and recorded. I'm requesting police dispatch.

• 26:09Speaker 15

  Unlike traditional alarm systems, Simply Safe uses smart AI cameras that spot potential threats and alert live US-based agents to help stop a break-in before it starts. Our agents intervene in under 30 seconds to deter intruders while they're still outside, preventing them from getting close to your family. Plus, you control your privacy and recordings. And with a 60-day money-back guarantee, you can try us risk-free. Monitoring and deterrence plans start around $1 a day. Order today to get 70% off a new system with professional monitoring. Save now at simplysafe.com/iheart. Simply Safe: Ahead of Crime in Real Time.

• 26:48Speaker 17

  30-second response time requires monitoring plan with outdoor protection starting at $49.99 a month. Visit simplysafe.com/licenses for alarm license information.

• 27:05Daniel Whiteson?

  All right, so we're back and we're talking about whether we could survive an interstellar trip, whether it's a good idea to build an ark where people can have their babies and their babies, babies, babies can one day visit an alien solar system, or whether these problems are insurmountable. We've talked about radiation, we've talked about money, we've talked about gravity. Now Kelly, tell us about knowledge. Why do we need to make sure knowledge doesn't decay along the way?

• 27:31Kelly Weinersmith?

  Well, we've already talked about how difficult it is to store knowledge in computers, or at least how careful you need to be to protect it from radiation. But another problem you're going to have is that the farther you get from Earth, the longer the communication delay. So if people are living on Mars, for example, there's a minimum three-minute communication delay just because it takes a long time for the message to go from Mars to Earth and then from Earth to Mars when you're ready to respond.

• 27:55Daniel Whiteson?

  I think that's really fascinating because, you know, the Earth is not small, but it's small compared to the speed of light. So you could have what feels like an instantaneous phone call with somebody in Tokyo, right, and the lag is imperceptible. But then, once you go to the moon or to Mars, like now it really ruins what it feels like to have a conversation, right? You could like ask a question, you gotta wait like six minutes to hear the answer. That's like not a conversation. It's more like writing letters back and forth.

• 28:19Kelly Weinersmith?

  It is. Yeah, I mean, I think even on the moon, you can have a close to realtime conversation, maybe a little bit of an awkward delay. But when you get to Mars, it's a minimum of three minutes, a maximum of something like 20 to 22 minutes. But when you're starting to get to Alpha Centauri, it's just going to keep extending, extending, extending until at some point you're not communicating anymore.

• 28:39Daniel Whiteson?

  So for example, if you like need IT support, you're like, hey, my MacBook is crashing. You don't want to wait four years for the answer to be like, turn it on and off again.

• 28:47Kelly Weinersmith?

  That's right. It's not helpful anymore at that point. You probably figured it out.

• 28:51Daniel Whiteson?

  Hope so. Or you're all dead. Yeah.

• 28:53Kelly Weinersmith?

  And I mean, that also means at some point, you're going to stop benefiting from any new knowledge that is created on Earth because it's going to be hard to get it to you and probably at some point impossible to get it to you. But it also means if somebody has an illness that you don't have anyone on the ship who's an expert in, that you're on your own. The surgical procedure that you're doing, you better hope you downloaded a good YouTube video for it because nobody's going to walk you through it in realtime. You really are on your own.

• 29:17Daniel Whiteson?

  Yeah, you can't look things up unless you bring like all of human knowledge with you somehow, download Wikipedia onto your ship's computers. I mean, that seems like it would be a good idea anyway, doesn't it?

• 29:27Kelly Weinersmith?

  No, absolutely. Yes. For both entertainment purposes and, you know, knowledge purposes, you should bring as much information with you as you can. That would absolutely be worth the storage space, in my opinion.

• 29:37Daniel Whiteson?

  What do you think takes more storage space, like Wikipedia or all the Fast and Furious movies?

• 29:42Kelly Weinersmith?

  Are you taking Wikipedia in every language?

• 29:45Daniel Whiteson?

  Ooh, good question.

• 29:47Kelly Weinersmith?

  I don't know.

• 29:47Daniel Whiteson?

  We better, though.

• 29:48Kelly Weinersmith?

  Yeah.

• 29:48Daniel Whiteson?

  Including the Scottish one, though the Scottish one turns out to be totally made up.

• 29:51Kelly Weinersmith?

  There's no Scottish Wikip- Wait, what?

• 29:53Daniel Whiteson?

  There is a Scottish Wikipedia, but it's mostly written by a guy who just invented what he thought Scottish should sound like.

• 29:59Kelly Weinersmith?

  Oh, my God.

• 30:00Daniel Whiteson?

  Yeah, it's bad.

• 30:01Kelly Weinersmith?

  I am regularly amazed by the amount of time that humans are willing to put into messing with each other. That must have taken a long time.

• 30:09Daniel Whiteson?

  Oh, yeah. He thought he was doing something good. No, he was like, hey, nobody else has done this. And I know how to do it, right? So

• 30:15Kelly Weinersmith?

  Oh, my goodness.

• 30:16Daniel Whiteson?

  The best intentions. Anyway, you should go read that story. It's hilarious.

• 30:19Kelly Weinersmith?

  Okay.

• 30:19Daniel Whiteson?

  But anyway, what is the impediment, though, to just bringing all of human knowledge with us? And saying like, all right, we're going to be cut off from the mothership. We're not going to get the latest advancements in quantum computing at the same moment. Maybe they can beam them to us as they come in. So we're a little behind. But why can't we just bring it all with us?

• 30:35Kelly Weinersmith?

  You can bring a ton of knowledge with you. But, you know, if you sat me down next to a bunch of textbooks on quantum computing, I could do nothing with that information.

• 30:43Daniel Whiteson?

  I see.

• 30:44Kelly Weinersmith?

  I mean, maybe after a couple of generations, I could. But this ties into the next problem that we're going to deal with, which is, you have to pick which humans you send with you, and what kind of knowledge they have, and how many of them you get. But I'm guessing you had another limitation in mind. Was it how many hard drives you'd have to bring? Or should I stop trying to guess what you're thinking?

• 31:02Daniel Whiteson?

  No, I think that your point is valid, that you can bring a bunch of knowledge, but just having that knowledge isn't enough. You need people who can digest it, and people who can put it to work. So you're essentially saying, make sure you bring enough physicists on board.

• 31:14Kelly Weinersmith?

  You know, you guys are good for a lot of stuff. I don't know how many practical problems. Also, you have to worry about, like, hygiene.

• 31:24Kelly Weinersmith?

  On an interstellar trip. But you should bring a couple cleanly physicists, probably. Yeah.

• 31:29Daniel Whiteson?

  I think the real problem here is that you need a breadth of knowledge, right?

• 31:32Kelly Weinersmith?

  Yeah.

• 31:33Daniel Whiteson?

  And so there's a question of like, what is the minimum size of a community that has enough technical knowledge and expertise to basically run independently of Earth? Because it's not like two people. It's not 10 people. And I'm guessing that's where you're going to go next, is like, how big a community you need, not just to have the knowledge, but also to like, have healthy babies.

• 31:52Kelly Weinersmith?

  Yeah. So I'm going to be focusing on the healthy babies part. But this occupations part is really important and is very hard to have a concrete answer for, because it depends on what you're willing to live without. I heard once that there's something like 100,000 medical specialties. And that number seems unreasonably large. But let's even say there's like, 1,000 medical specialties.

• 32:11Daniel Whiteson?

  Okay.

• 32:11Kelly Weinersmith?

  You'd probably want one person from each of those specialties, or like duplicates of all of those people. But you also need janitors, and plumbers, and engineers, and farmers. And there's just so many different kinds of people you would like to have there. But you might not be able to have everyone you want there. Like, you know, you probably couldn't have three of every medical specialist if there are 100,000 kinds. So you're going to have to sort of pick and choose, and decide what you're willing to do without.

• 32:38Daniel Whiteson?

  I think there's also an interesting interplay there between are you just trying to survive the trip or are you trying to bring the seeds of a future civilization with you? Because think about just like pencils. Okay, you need a lot of pencils on an 80,000 year journey. Maybe you could just stock a bunch of pencils, right? Bring a bunch of pencils or like light bulbs or whatever. And you might be able to survive the journey and not use up all the light bulbs and pencils. But once you get there, you might still want light bulbs and pencils in a thousand years. And so what you need to do is bring like the manufacturing capacity to produce all of the goodies that we expect for a certain quality of life, or to severely restrict the goodies that you're expecting these people to live without. So you really need to bring like

• 33:20Daniel Whiteson?

  your entire manufacturing supply chain and pipeline with you if you're going to seed a civilization on the other end of this, not just like visit Alpha Centauri and turn around and come back.

• 33:30Kelly Weinersmith?

  Yeah. So let's jump for a second to a conversation about what you bring with you. So yeah, you would want to maybe bring all the manufacturing stuff to make pencils. Additionally, we should have invited Katrina on the show briefly because you're going to want to make sure, for example, you have a diversity of microbes. But how do you know which ones to bring?

• 33:45Daniel Whiteson?

  You just bring all the poop on earth. That's the easy solution. That's what she would say.

• 33:49Kelly Weinersmith?

  Okay, but a lot of that poop on earth has parasites. And while I don't want to live in a world without interesting parasites to study, I think most people would, although I prefer parasites that aren't infecting people. But anyway, so yeah, you got to figure out what kind of microbes and that requires knowledge that we don't necessarily even have yet. What kind of microbes do you want to bring with you? But you also need to bring medicine, but medicine expires and 80,000 years is a long time. So you're probably going to want to bring the equipment that you need to make more medicine. And there are some designs for 3D printers that will print medicine on demand. But you need to make sure you've got the raw materials for that.

• 34:23Daniel Whiteson?

  Yeah, exactly. It feels like you're cutting that very tip off a very complex pyramid of manufacturing and civilization, and it's going to crumble eventually. It feels very difficult to maintain the same level of civilization if you're not bringing the whole pyramid with you. And it turns out the pyramid is huge, right? Like just to make a pencil requires an enormous manufacturing capacity, lots of different specialties.

• 34:46Kelly Weinersmith?

  Our global supply chains are amazing. We rely on them for so many things. That pencil takes a million people thing came from somewhere. And one of these days I want to figure out, was it a Milton Friedman essay?

• 34:57Daniel Whiteson?

  I don't know. I hope it wasn't Malcolm Gladwell because you can't trust anything in those books.

• 35:02Kelly Weinersmith?

  We're on the record now. All right, let's go ahead and just accept that there's a lot of stuff that you're going to need to bring if you want to keep your standard of living reasonably high and also a lot of stuff that you're going to need to bring or be able to build so that you can replace parts of your ship as they break down over time in the very harsh environment of space. So now let's jump to biology, the good part. Let's get to the good part.

• 35:24Daniel Whiteson?

  All right. Are we talking about parasites? Minimum number of parasites to bring to office entirely?

• 35:28Kelly Weinersmith?

  Unfortunately, no, I couldn't figure out a way to really shoehorn parasites in more than once.

• 35:33Daniel Whiteson?

  I'm ready for it, though, when you bring it up. I'm ready for it.

• 35:36Kelly Weinersmith?

  Okay, good.

• 35:36Daniel Whiteson?

  No, but how big a group do we need, like biologically, to keep our community healthy and to make sure we don't like all suffer from some genetic defect that like one guy has on board? How big a population do we need?

• 35:48Kelly Weinersmith?

  Yeah, this is a really difficult question. So we don't necessarily know what kind of diversity we need. So it would be great to have people, for example, that are resistant to radiation in case we can't shield all of it. But we don't really know what genes are important for that at this point. So the more diversity you can have, the better. You also want people who are not closely related to each other, because we all have some genes that are carrying the code for negative traits. So you know, it could be sickle cell anemia or something like that, where if you get two versions of the gene that caused the disease, you're in a lot more trouble than if you just have one.

• 36:25Daniel Whiteson?

  I wonder, from an evolutionary point of view, if this is a scenario where you actually want to be susceptible to radiation because it induces a higher mutation rate in your babies? And that might mean that you lose a bunch because like they have bad mutations, but you also might like invent some new weird like spacefaring hardy human that can like, I don't know, extrude pencils from some new orifice or something useful. I don't know. Like, is there a possibility there that more mutation might actually be beneficial?

• 36:50Kelly Weinersmith?

  So mutation is a mechanism through which you get more genetic diversity and some of that could be good. I think our expectation would be statistically, you'd probably get a lot more things breaking than a lot more things resulting in pencils coming out of your nose at appropriate times or something. And I think a lot of those mutations are going to be, you know, like causing cancer as you're older and not necessarily resulting in like really well adapted babies, but who knows?

• 37:18Daniel Whiteson?

  Who knows? All right.

• 37:19Kelly Weinersmith?

  So I've seen a bunch of estimates for how many people you need and you do need to be careful about who these people are. So like, yes, we talked about you want doctors and stuff like that, but when you're thinking about the number of people you need, the number of people over 60, it's great to have their knowledge, great to have their help, but they're not going to be contributing to having children. So you need to think about the number of reproductively aged individuals and you need to think a little bit about the mix of people. So if you bring, you know, 10,000 men, you better also have artificial wombs or something at that point. So you need to think about the makeup.

• 37:51Daniel Whiteson?

  Well, dig into that for a moment for us. Like, what is the best gender ratio? I mean, because like a woman can't be pregnant from two men simultaneously, but a man can have multiple partners.

• 38:00Kelly Weinersmith?

  It depends on what your goal is and frankly, it depends on what your culture is willing to accept because I think you don't want to send people into interstellar space under conditions that they would, you know, find abhorrent.

• 38:09Daniel Whiteson?

  Yes.

• 38:10Kelly Weinersmith?

  If your goal is to just have as many babies as possible and you've set up the interstellar ship to be able to scale to feed and provide oxygen for a rapidly expanding population, then you could send exclusively women who got pregnant using embryos that you sent with you. There are ways to maximize the speed at which the population increases, but I don't necessarily know that the goal and route is going to be to increase numbers as fast as possible. Cause if you just wanted to have a lot of people, you could have just started with a lot more people. So I think you want to find a makeup where you can sustain your population numbers and I don't necessarily know if the best way to go is 50 50.

• 38:48Daniel Whiteson?

  Well, I think your point is a good one though. If you want your people to be happy, then you're going to have to create an environment they're going to like to live in. And currently most people enjoy monogamous relationships or, you know, one to one ratios, which means you're going to need roughly a gender balance.

• 39:03Kelly Weinersmith?

  So I found an estimate where someone did a computer simulation and they found that you could possibly get away with 98 people if.

• 39:11Daniel Whiteson?

  98,000 or 90 people?

• 39:13Kelly Weinersmith?

  98 individuals.

• 39:15Daniel Whiteson?

  What?

• 39:16Kelly Weinersmith?

  If every generation, they mated with whoever a computer program told them to mate with, based on their genetic makeup. So this is an interesting thought experiment for a lower bound, but if you're thinking about what humans are willing to accept, that's probably not going to work out.

• 39:32Daniel Whiteson?

  And for this study, how do they define success? You have like a population downstream that's healthy and doesn't have a lot of recessive traits that are hurting people?

• 39:42Kelly Weinersmith?

  I forget the exact details, but it was something like after five generations, would you expect the population to still persist or would they have had inbreeding problems or something like that?

• 39:52Daniel Whiteson?

  Well, it's really fascinating because I've heard some of these studies that speculate the humanity might have had bottlenecks early on, you know, down to like as many as 10,000 individuals on the planet. And here we are, you know, eight billion people later doing pretty well. So it's not implausible to me that you could get down to a few thousand. 98 seems kind of crazy.

• 40:11Kelly Weinersmith?

  And there are plenty of people who will also point out that there are indigenous peoples living in populations of something like 100 to 500. But what those numbers often miss is that those indigenous populations are often interacting with others and intermarrying. And so actually, the population that is interbreeding is much larger than the individual communities themselves. But yeah, I've seen estimates that seem pretty reasonable that range from about 5,000 to 40,000 people of reproductive age. The 40,000 number seemed a little bit more realistic to me. So it was taking into account the ability to survive five generations, even if a black plague-like catastrophe comes along. And so this is incorporating like, what if some bacteria in our gut mutate and kills

• 40:56Kelly Weinersmith?

  25% of us? Like you might have to assume that every once in a while, you're going to lose people. So estimates range from 98 to about 40,000 and really depend on the assumptions you're making.

• 41:06Daniel Whiteson?

  Well, keeping in mind our constraints, even if money isn't an obstacle, of course, in reality it is. And we know that size is an issue and fuel and all that stuff. And so if what we want to do is keep the ship small, then we want to keep these numbers low. And I was really interested in your comment about how you could keep it down to around 100 if people accepted, you know, computer-assigned dating. And I'm wondering how far we could push that? Like, could we make it even lower if we assume some sort of advanced technology to like modify your genetics or correct issues or something? Couldn't the interaction between biology and technology really change how small we could go?

• 41:41Kelly Weinersmith?

  I hear a lot of engineers propose stuff like this and it totally makes sense. It's true, it could work, but when ideas like this come like head to head with human behavior, they tend to fall apart. I mean, you could have five women who start the trip with a vat of freeze dried sperm from lots of different people and you could maybe make it. But now you've got problems with, well, do you have enough doctors and enough engineers and enough people to work the farm? So there's a lot of reasons why going big has a lot of benefits.

• 42:09Daniel Whiteson?

  I think it's funding the mental image of that of freeze dried sperm. Why wouldn't you have them, you know, like delicate test tubes, you know, imagining like, you know, liquid nitrogen flowing over them or something. Instead, your words give me a mental image of like a barrel of this stuff.

• 42:24Kelly Weinersmith?

  You started this gooey theme and I was just kind of running with it, but you're right. They'll probably be in vials in a tube of liquid nitrogen or something like that. Yeah, we'll treat them better.

• 42:33Daniel Whiteson?

  Delicately clinking glasses and stuff like that.

• 42:35Kelly Weinersmith?

  That's right. Having technology to help with reproduction and bringing along extragenetic diversity in the form of embryos, stuff like this can really help with diversity problems. But again, each generation, you're going to have to deal with the wants and desires of the humans who are there, who are going to want to find partners that make them feel complete and who may or may not be comfortable with being told, hey, your partner isn't as genetically diverse as you might want. Sorry, this is what five generations in an interstellar ship does. So you are going to have the embryo for which we provide 50% of the genetic information. And not everybody is likely to love that. And then what do you do when people get pregnant unintentionally?

• 43:14Daniel Whiteson?

  Yeah, exactly. I think that's super fascinating and it touches on another whole area of questions of like how you manage the people on board and what laws do you have and what punishments can you do? Like you shooting people out the airlock if they're not dating the right person? It's crazy, but you know, on ships, the captain's in charge and for a reason. And so anyway, that's a whole other issue we could dig into another time of laws onboard interstellar trips. For now, let's take a break and when we come back, let's hear about a strategy that might make that all moot. What if everybody just sleeps their way to Alpha Centauri?

• 43:52Speaker 12

  Hey, it's Nile Rodgers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything. This week, I'm joined by my friend, John Legend. How does music actually enter your mind?

• 44:15Speaker 13

  I'm not sure why or how the music comes to me, but I think people who love music and write music, our brains are just filled with music.

• 44:24Speaker 12

  Right.

• 44:25Speaker 13

  Like, we have listened to so much music, we've been a part of so much music. I think of the story that I want to tell, the mood that I want to create with the music, start playing chords, see where they lead me.

• 44:36Speaker 12

  Sometimes, I'm just not even thinking about music, right? And I hear this little thing, and I go, oh, that could be this.

• 44:46Speaker 13

  You know, you just have to be ready for when the inspiration hits.

• 44:49Speaker 12

  It comes. Experience Before the Moment, a Lincoln original series on the iHeart Radio app, YouTube, or wherever you get your podcasts.

• 44:59Speaker 14

  This is Hoda Kotb from Joy 101 with Hoda Kotb. Have you started your holiday shopping yet? This time of year always feels like the list just keeps growing. Gifts for family, gifts for friends, stocking stuffers, plus all the everyday things you still have to buy, like groceries and gas. That's why being a little strategic about the spending on gifts and those everyday needs is key. With the Chase Freedom Flex card, you can be a little savvier. Finding the right gift feels good, and maximizing cash back feels even better. Freedom Flex offers plenty of ways to earn more. You get 5% cash back on popular rotating quarterly categories, 3% on dining and drugstores, and 1% on all other purchases.

• 45:42Speaker 14

  So while you're checking names off your holiday list, those gifts can be a treat for you, too. This holiday season, let Freedom Flex reward you. More ways to earn, more ways to get rewarded. So sign up for the Chase Freedom Flex card. Learn more at chase.com/get

• 45:59Speaker 14

  Flex. This is a paid collaboration with Chase Freedom Flex. Cards issued by J P Morgan Chase Bank and a member F D I C. Subject to credit approval. Offer subject to change. Terms apply.

• 46:11Speaker 15

  Right now, you can save seventy percent on Simply Safe home security. Traditional security systems only alert you after a break in has already happened, and that's too late. Simply Safe is changing that.

• 46:25Speaker 16

  Stop. This is Simply Safe. You're being monitored and recorded. I'm requesting police dispatch.

• 46:30Speaker 15

  Using the outdoor camera series two and advanced A I alerts, our live U S based agents identify potential threats on your property and help deter them. So the intruder never gets into your house. The break in never happens. Because we don't just alert, we stop crime before it starts. Simply Safe monitoring and deterrence plans start around a dollar a day with no long term contracts. Order today to get seventy percent off a new system with professional monitoring. Save now at simplysafe.com slash I heart. Simply Safe. Ahead of crime. In real time.

• 47:05Speaker 17

  Outdoor deterrence plans start at forty nine ninety nine a month. Visit simplysafe.com slash licenses for alarm license information.

• 47:20Daniel Whiteson?

  All right, we're back and we are facing all the questions for taking humans to another solar system. Radiation and gravity and breeding and knowledge. And all these things require keeping people awake, having a functioning society on board. People sitting there munching on their snacks and watching Fast and Furious. What if Kelly, we decide not to? What if we just put everybody out for the journey? What if we can like freeze them or hibernate them? You see this a lot in science fiction. Is that realistic? And where is the technology now?

• 47:50Kelly Weinersmith?

  It's not realistic with current technology, but I wouldn't say it's absolutely impossible. You can't just put everybody to sleep as sleep is technically defined because while you're sleeping, you still have metabolic processes happening. You're still aging. So if you were asleep, you'd still need to have like fluids put in through an IV. You'd need to be fed. Machines would have to roll you over. Sleeping wouldn't really cut it.

• 48:12Daniel Whiteson?

  It'd be like a coma and nobody wants to be in a coma for 80,000 years. And you can't live that long, even in a coma, right? It doesn't extend your life to sleep.

• 48:19Kelly Weinersmith?

  Right, exactly. That's a total nonstarter. The next step up from that would be hibernation. And so hibernation, you have a reduced temperature. You still have some metabolic stuff happening, but the metabolic activity is way down. So like your caloric needs go way down. You need less. You're using the restroom less, stuff like that. And there's lots of animals that hibernate. You know, you've got bears, squirrels, marmots, prairie dogs, groundhogs. Hibernation happens a lot. But it's worth noting that, one, hibernation doesn't keep these animals alive forever. And sometimes animals die while hibernating. So it's not like you're 100% safe when you go into a hibernation state.

• 48:57Daniel Whiteson?

  And can every animal hibernate? I mean, bears and squirrels, they do these things themselves. But like, I've never hibernated. Do humans hibernate?

• 49:03Kelly Weinersmith?

  I would like to hibernate sometimes when it's too cold out, but no, humans do not hibernate. It's not clear how we would put humans into a hibernation-like state. It's tantalizing that other mammals can do it, but it doesn't necessarily mean that if we learned the right tricks, humans could do it too. Humans do sometimes survive being very cold, so like in a very hypothermic state. And every once in a while, if people have particular problems. So I've read about somebody who had rabies and they were trying to slow down the movement of rabies and give the body some time to respond and the vaccine some time to work. And so they essentially put the person in a very cold state to slow things down. And people can survive, but it's not like it's great for the body. And it's not like it's extending their lifetime.

• 49:48Kelly Weinersmith?

  So you would still end up with people dying in a hibernation state, probably.

• 49:53Daniel Whiteson?

  All right. So we can't just knock people out with NyQuil. We can't just turn down the temperature a little bit so people get cold and hibernate. What if we go even colder? What if we like dip everyone in liquid helium and turn them into human circles? Will that help? Is that possible? I mean, you hear about this all the time on science fiction and on The Simpsons, for example, or Futurama. I forget which one it is. But is this just fictional nonsense or is the science moving us in that direction?

• 50:21Kelly Weinersmith?

  Scientists are trying to move us in that direction. Some of them are. So there have been people who very soon after they passed away had their body cryogenically frozen in the hopes that at some point we'll figure out the cure for their disease or figure out some way to sort of wake them back up again, or figure out some way to upload their brain to a computer once we really understand brains so that their consciousness or something can be brought back to life.

• 50:46Daniel Whiteson?

  Wait, they freeze them after they die? Don't you need to freeze them before they die? Otherwise you're just thawing a corpse, right?

• 50:52Kelly Weinersmith?

  I was under the impression that for ethical purposes, you do it like as soon as they're dead and then hope you can find some way to get everything moving again.

• 51:01Daniel Whiteson?

  To undead them.

• 51:01Kelly Weinersmith?

  To undead. I mean, you know, people's like heart stops. You could say they're dead, but you can get them kicking again as long as you do it quickly.

• 51:08Daniel Whiteson?

  Interesting.

• 51:09Kelly Weinersmith?

  I think that's the plan. But you know, if anybody has like frozen people and want to tell us about it, we'd love more information, but it's.

• 51:16Daniel Whiteson?

  Call us at FBI.gov.

• 51:18Kelly Weinersmith?

  That's right. That's right. Yeah. I'm hoping that you had permission and signed waivers and stuff first.

• 51:23Daniel Whiteson?

  All right. But before we try this on humans, I imagine we're going to test this on like frogs or kittens or something. How is that progressing?

• 51:30Kelly Weinersmith?

  Well, so there are some animals that freeze naturally. So for example, there are some frogs in cold climates that have something like antifreeze in their blood. So the way antifreeze in your car works is it lets things get a little bit colder without actually freezing. I think that there's some combination of that happening and the cells also using some additional mechanisms to make them robust to avoid bursting as water expands.

• 51:53Daniel Whiteson?

  Yeah, I think that is what's happening. I think for frogs, what's happening also is that like they're producing some substances, antifreeze, you say, which maybe prevents ice crystals from forming. And so like. Basically, if you dope water with this stuff, then its chemical properties change. And I think it's so incredible that water has this bizarre behavior that when it freezes, it gets larger. It's very unusual, right? Most things, when you freeze them, they get smaller. But the fact that ice is less dense than water means fish, for example, can survive in the lake, right? Because the ice is on the top rather than on the bottom. But it also means that if you freeze, you explode. So it's this funny double edged sword of chemistry.

• 52:29Kelly Weinersmith?

  Well, I believe there are some fish in Antarctica who can survive freezing also if they end up in that like frozen layer of ice. So the point is, there's a variety of animals that can survive freezing. And while humans at this point cannot survive freezing, maybe there's some lessons that we can learn from these animals or from tardigrades to try to figure out a way where we could cryogenically preserve live people, thaw them out and bring them back to life. But it's worth noting that as far as I know, there's never been a frog, for example, that was frozen for 10,000 years and then brought back to life, you know? Like, we talked about some tardigrades that managed to be frozen for a very long time. But I think, you know, when you get to vertebrate level, it's even harder to survive freezing for a very long time.

• 53:14Kelly Weinersmith?

  So it's not clear that cryogenics will be compatible with the human body or that it will be compatible with the human body on the time scales needed to get to Alpha Centauri.

• 53:23Daniel Whiteson?

  It's too bad we don't have the biological technology of plants. You know, seeds are incredible. I read stories where they like dug up ancient seeds and like planted them and gave them water and they sprouted and it's like, oh, here's a date palm whose parent grew like thousands of years ago and it just sat there. It's totally shelf stable for thousands of years. It's incredible biological technology. It's too bad we don't have seeds.

• 53:46Kelly Weinersmith?

  You know, trees make no sense to me. My husband has been gardening lately and he'll say things to me about like, oh, well, you can just cut that branch off and put it in the soil and you'll get a new tree. And I'm like, that's not how life works. You can't do that to me, but it works with trees.

• 54:00Daniel Whiteson?

  I know. I remember saying to him, like, why can't I just stick my arm in the ground and grow a new person?

• 54:04Kelly Weinersmith?

  That's right. Yeah, trees are wild. And so some of the most sci fi ish plans I've come across involve things like having an artificial womb with freeze dried embryos that you send with you.

• 54:17Daniel Whiteson?

  Because embryos, we can freeze and revive, right? That's amazing.

• 54:20Kelly Weinersmith?

  It is amazing. Yeah. And so I don't know that you can freeze them for 80,000 years for the trip to Alpha Centauri. But you know, if you get there faster and you can probably move much faster if you don't have squishy humans on board to worry about.

• 54:31Daniel Whiteson?

  Some of my best friends have two kids and both of them came from frozen embryos. One kid is two years older, but they're actually the same age. It's just that one of them has been unfrozen for two more years. And I think about that every time I see these brothers, I'm like, you guys are actually the same age. It's just one of you was frozen for two years.

• 54:49Kelly Weinersmith?

  That is amazing. Reproductive technology is incredible, the things that we're able to do.

• 54:53Daniel Whiteson?

  Yeah. So you're going to put this in the maybe category that we potentially could develop cryogenic technology that could freeze humans and unfreeze them after thousands of years. It's not clear how we would do it now, but you're not going to say it's impossible.

• 55:06Kelly Weinersmith?

  I'm going to put the cryogenic humans on the fairly unlikely.

• 55:10Daniel Whiteson?

  Oh, no.

• 55:11Kelly Weinersmith?

  For the timeframes necessary to get to Alpha Centauri. If you could get one of those propulsion techniques to get you there in like, five years, and you just had to freeze people so they didn't get bored during the trip, then maybe you could get away with that. But when you think about what else humans would need when you wake them up, it starts getting complicated. So you know, if those humans ever want to have a fresh egg, you also need to figure out a way to get the chickens going. You know, you also need to store the food for them. Like, it gets incredibly complicated. But you know, maybe you could just bring a bunch of genetic material with you and have a lot of robots that start planting the farm, you know, a couple of months before the humans are going to be gestated in the artificial womb. But now who's going to raise them? Like, as a

• 55:54Kelly Weinersmith?

  parent, it is amazing to me how much work it takes to get children to like, just shower or brush their teeth. Like, there's so much nagging that needs to happen.

• 56:04Daniel Whiteson?

  You're out in a crowd and you look at all those people, you're like, wow, all these people were raised, some parents like taught these humans how to survive and exist in a crowd and like, be functional. Like, that's so much work. Wow.

• 56:16Kelly Weinersmith?

  It is. Yeah, culture is incredible. The fact that we've managed to get ourselves here by like, policing each other's behaviors is fantastic.

• 56:25Daniel Whiteson?

  All right. Well, I see you struggling to not be the negative Nellie and to not want to say no is impossible, but it seems like, yeah, pretty implausible.

• 56:33Kelly Weinersmith?

  I would say within my lifetime, not going to happen.

• 56:36Daniel Whiteson?

  All right.

• 56:36Kelly Weinersmith?

  But science often has breakthroughs that surprise me. And in a couple lifetimes, maybe it would happen.

• 56:42Daniel Whiteson?

  But the embryos and parental robots thing, that's a cultural issue, right? We think that technologically that might actually be possible. I mean, you might get weird humans that might kill all each other, or they might like launch nukes back at us or something. But in terms of like getting people to the other planet and growing them there, that could work, right?

• 57:01Kelly Weinersmith?

  It's possible that it could work. I mean, I think there's a lot of things we don't understand very well. So for example, when babies are born through a mother's body, they get slathered in bacteria that are important for the way their bodies work. They get food to the bacteria in their guts from breast milk. I think we don't really understand what would happen to humans if they were raised by robots and only encountered other babies of a similar age or other people of a similar age. But somebody should write a sci fi novel about that.

• 57:27Daniel Whiteson?

  Or we should just do it and see what happens.

• 57:30Kelly Weinersmith?

  Yeah, that sounds totally ethical. Totally.

• 57:34Daniel Whiteson?

  All right. So it sounds like there's a lot of challenges to getting humans from here to Alpha Centauri. Even if you've solved all the physics problems we raised in the last episode, there are a lot of biological problems, a lot of cultural problems, a lot of technological problems to solve, getting the humans there safely.

• 57:49Kelly Weinersmith?

  Yes. And we didn't touch on a lot of the society, the cultural, the ethical problems. There's a lot more stuff we could talk about. And also I recommend Ed Regis's book Starbound, which is all about interstellar travel and some of the challenges that you encounter along the way. That was an interesting read.

• 58:03Daniel Whiteson?

  So if somebody wants to sell you a ticket to Alpha Centauri, we're going to officially recommend, hmm, maybe.

• 58:08Kelly Weinersmith?

  Maybe. Yeah, I would not buy that ticket, but I'm sure other people would. And I'm sure it would be an amazing experience.

• 58:15Daniel Whiteson?

  Yeah. And I hope you enjoy Fast and Furious number 742 on your trip.

• 58:19Kelly Weinersmith?

  Enjoy.

• 58:27Kelly Weinersmith?

  Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We would love to hear from you.

• 58:33Daniel Whiteson?

  We really would. We want to know what questions you have about this extraordinary universe.

• 58:39Kelly Weinersmith?

  We want to know your thoughts on recent shows, suggestions for future shows. If you contact us, we will get back to you.

• 58:45Daniel Whiteson?

  We really mean it. We answer every message. Email us at [email protected].

• 58:52Kelly Weinersmith?

  Or you can find us on social media. We have accounts on X, Instagram, Blue Sky, and on all of those platforms you can find us at D and K Universe.

• 59:01Daniel Whiteson?

  Don't be shy. Write to us.

• 59:06Speaker 18

  What's that? My fresh detector. Uh, your what? There it is. What is it detecting? Fresh produce, fresh meat. Okay, what happens if it detects something really fresh?

• 59:20Speaker 18

  Apparently, we celebrate.

• 59:23Speaker 19

  At Food Lion, you can count on fresh food at fresher prices when your fresh detector is going off. Head to your local Food Lion or shop at foodlion.com.

• 59:33Speaker 20

  Hey, it's Covino and Rich Davis from Covino and Rich. Buy smart, drive for less, and trade for more. That's Toyota affordability. And it starts with a great deal on an off-road, ready Tacoma or half-ton Tundra, two of Toyota's most capable and longest-lasting trucks. Combining power for work, tech for adventures, and style in between. Built on reputation for quality and reliability, Toyota trucks are known for holding their value, which can mean big savings when it's time for your next Toyota. So get a great deal today and great value tomorrow. Shop toyota.com for more. Toyota, let's go places.

• 1:00:08Speaker 21

  OnDeck is built to back small businesses like yours. Whether you're buying equipment, expanding your team, or bridging cash flow gaps, OnDeck's loans up to $400,000 help make it happen fast. Rated A+ by the Better Business Bureau and earning thousands of five-star TrustPilot reviews, OnDeck delivers funding you can count on. Apply in minutes at ondeck.com. Depending on certain loan attributes, your business loan may be issued by OnDeck or Celtic Bank. OnDeck does not lend in North Dakota. All loans and amounts subject to lender approval.

• 1:00:37Speaker 22

  You've watched them take their first steps, heard their first words, but there's one first that changes everything: the moment your child realizes they can read. At Hooked on Phonics, we've spent 40 years making that moment easier. Our award-winning app pairs with a monthly practice pack: real books, workbooks, and stickers, so learning feels like play. Give your child the confidence to love reading. Start today for just $1 at hookedonphonics.com. This is an iHeart Podcast. Guaranteed human.