Musk on the Moon

This is an iHeart podcast. Guaranteed Human. Rural Britain, you've suffered too long. Your days of sluggish broadband are over. We're connecting rural homes to full fiber with thousands more joining every month. T minus five. The gigaverse is expanding before my very eyes. Gigaclear, faster broadband for rural Britain from only 19 pounds per month. We have lived off. T's and C's apply. H-a month contract. Prices may rise during contract. Check availability at gigaclear.com. Elon Musk recently announced that SpaceX is shifting its focus away from a self-sustaining city on Mars and will instead build a self-growing city on the moon. Musk explains that building on the moon makes sense because you can launch a rocket to leave for the moon every 10 days. And it only takes two days to get there. But for Mars, because you have to wait for the planets to align nicely, you can only leave for a trip every 26 months and it takes six months to get there. So, he argues, you can go to the moon more often and more quickly. So it makes more sense to start there. But orbital mechanics hasn't like recently changed. These facts that Musk is stating have been true for the history of SpaceX and of course for much longer than that. So why the change in heart now? And fickle human hearts aside, how feasible are these plans? We'll chat about how difficult it will be to create a self-growing or self-sustaining city on the moon or Mars. And we'll chat about Musk's plans to build AI satellites on the moon and launch them into deep space using a mass driver. Welcome to Daniel and Kelly's Extraordinary Universe. Hi, I'm Daniel. I'm a particle physicist and I want humanity to occupy the stars. But I want to stay here on Earth. Hello, I'm Kelly Wienersmith. I study parasites and space and I'm also cool with humanity occupying the stars as long as we do it like ethically and carefully. But I am also staying down here on Earth with the goats and the moths and my kids and my husband. All right. Well, if neither of us are going to Mars or the moon or the belt, then my question for you today, Kelly, is what is the most dangerous or uncomfortable place you'd be willing to visit? I'd be willing to visit. I mean, you're not taking a ride to the moon. Would you take a trip to the bottom of the ocean or to Antarctica? I would maybe go to Antarctica. It's kind of like beautiful there. I could maybe be convinced. I would like to visit a desert. The desert has a sort of beauty all its own, especially if I could ride a camel. That'd be fun. Visit the desert. Is the desert such an exotic place for you? I mean, I live in the desert. Oh, well, I mean, I mean, I like a real desert. Oh, yeah. A real desert. You're looking down your nose at the Southwest, huh? I mean, you turn a tap and you've got water. And so I mean like a desert where like everywhere you look, there's sand dunes like in the middle of the desert, you know? I see. You heard it here first, folks. Death Valley doesn't qualify as a desert according to Kelly Wintersman. All right. I'm sorry. I'm sorry. Well, what about you? What's your answer? Having just experienced international business class for the first time. I think the answer is nowhere. Like I really just don't want to go anywhere uncomfortable. It's just not fun. Yeah. No, I'm going to be a total wimp about it. I feel like I have to stay alive for my kids. Otherwise, my answer could be a bit more exotic. But yeah, I got to stay alive for my kids right now. Like I even have plausible scientific reasons to go to Antarctica. And I know a guy who goes quite often. I could probably go if I wanted to. But yeah, just no interest in going to Antarctica. It seems miserable. I have friends who go to Antarctica and they're like, you have no desire to go. And I'm like, oh, no, no, no, no, no, no. I have friends who jumped in the water in Antarctica. Scott and Joe, you two are nuts. Nuts. Wow. I'm sorry. Wow. Well, speaking of nuts, today we're talking about planes to settle the moon. And if you didn't already pick up on it and this is your first episode of this podcast and you have no idea how Kelly feels about settling space, then you might have gotten a hint about where this is going. Yes, that's right. We are talking today about Elon Musk's about face. He has for a long time been talking about settling Mars. You can see him wearing his Occupy Mars shirt all the time. He's well known for saying that he wants to have a self-sustaining settlement on Mars with a million people in the next 20 to 30 years. What's his most outrageous prediction for when he's going to start sending people to Mars that like didn't come true? I mean, I think not that long ago, he was predicting that he was going to try to get like some people heading Mars word in like, I think, I think we're in a launch window in 2026. So, you know, like sometime in the next couple of years, Starship would be bringing people Mars word. But I don't pay too much attention. You know, like Musk is well known for saying that SpaceX turns impossible into late. That's catchy. That's good. That is good. And SpaceX has done absolutely amazing things. Like Zach and I were very frustrated when we were writing Soonish, which was a book about emerging technologies. And we had this chapter about lowering the cost of sending mass to space. And SpaceX just kept doing one absolutely amazing thing after another. And we kept having to update that chapter because we were like, holy cow, they're like revolutionizing space launch as we're writing this chapter. They're catching rockets with chopsticks. It's amazing. No, it is absolutely amazing. And so I, every once in a while, I'll talk to someone who will be like, oh, Musk and SpaceX haven't done anything amazing. There have been reusable rockets before. And to me, this like borders on conspiracy theory. Yeah. Like, yeah, clearly this has been revolutionary. You can argue about whether or not you're excited about there being more satellites in space, for example. But anyway, I think it's been very impressive. No, it's important to be clear-eyed and to be fair about it. And you give credit where credit is due. Otherwise, you have no credibility. You're just out there to bash on a rich nerd. But do you have any insight into why Mars was the target? I mean, Mars has always been further and harder. Why did he focus on Mars? Yeah. So my sense is that Musk has always been into science fiction and he's always been sort of excited about big space goals. After he got his money from what's now called PayPal, he was excited about Mars even then. He wanted to send something like a little like greenhouse to Mars and then take a video of like a plant growing on the Martian surface. And he thought that would be really inspirational for people to see a plant growing on Mars and like, yes, absolutely. And so my guess is that why he's excited about Mars is because Mars actually is one of the best places in the solar system to have a self-sustaining settlement for humans if you were going to do it anywhere. But hold on. That's like is one of the best in the sense that there's only one good one. And Mars is like, you know, a distant second. It's like saying eating garbage is some of the best food you can eat. It was like, yeah, but there is a better option just right here. Well, yes. Right. So everything else in space sucks so much worse than Mars. I mean, like, so Earth is perfect. And then Mars is the least bad. Yeah. Next. And we're going to get into that. Eating garbage is better than eating sewage. And that's basically the argument. All right. So tell us about the recent news about Musk pivoting. Yeah. So there's there's been this recent surprising pivot where now Musk is saying that they're going to have a self growing or self sustaining depends on you know, whether you're talking about a tweet or a speech he gave recently. In the tweet, he said self growing, but in a speech I listened to, he said self sustaining city on the moon in, you know, maybe even less than 10 years. And when you ask him why, he says that it's because you can get to the moon faster. So the moon, you can leave every 10 days, a window opens, whereas you can only leave to get to Mars once every something like 26 months, because you have to wait until Mars and Earth are like aligned in a nice way where you can like make that journey the shortest. And that's because the Earth and Mars don't orbit the Sun in a coordinated way. So sometimes they're like on opposite sides of the Sun. It makes no sense to try to get to Mars. And sometimes they're lined up like one car passing the other one on a race track. Exactly. Right. And the moon is nice enough to always be about the same distance away from us at all times. The Sun never comes between the Earth and the moon. That's amazing. I know. It's very convenient. It's very convenient. That would be very cool to see, though. But yeah, Celeste Gilles, that just never happened. That's right. That's right. And when that window does open up and you leave for the moon, it takes you like about two days, maybe a little more to get there. Whereas if you leave for Mars, it takes you between six to nine months to get there. Yeah. And so you can leave for the moon a lot more often and you get there a lot quicker. But clarify for us the distinction you made between self-sustaining and self-growing. He's one of them like a plant and the other one. What's what's the distinction? Yeah. So I've been trying to figure that out as well. So self-sustaining is the word that he tends to use for Mars. And what he means by that is if something catastrophic happens to Earth, Mars would be fine on its own. Makes sense. And I, you know, I so I wrote this book called A City on Mars, where I sort of critique his timeline for how long it would take to get to self-sustaining. I don't think you could do that in 20 to 30 years. But he first started using this word self-growing on the moon. And when we start talking about the moon in a little bit later in the show, I want to dig into why I think he may have used self-growing initially instead of self-sustaining because the moon lacks a lot of things that I think that you would need to have a self-sustaining society because it turns out the moon is a really bad place to live. And it's lacking stuff like carbon. It's got some carbon, but not a lot. And we're carbon based like organisms. And so like even just the like basic building blocks that you need to make humans, we're going to have to bring with us to the moon. And so I'm guessing that's why he used self-growing initially. Yeah, I don't know. Maybe you could grow businesses there, but self-sustaining would take a lot of work. What's interesting to me is that Musk is saying like, oh, we can get to the moon faster. And that's why we got to start there. But this has always been true. It's not like the moon was recently moved to get easier to get to. Right. Right. And I don't think that Musk like woke up 10 days ago. We're recording this in like mid February. And he, you know, he said this in like early ish February. I don't think that Musk woke up like 10 days ago and was like, oh, wait a minute. The moon is closer. And so like why the shift? And so there's loads of people who are speculating on the cause of the shift. I don't think we should speculate a ton. I don't want to spend a lot of, you know, breath on guessing. But many people have noted that blue origin is finally starting to catch up to SpaceX. After being behind for a long time, blue origin is now starting to talk about doing more activity on the moon and having like a lunar lander. And this is at a time when there's rumors that SpaceX is going to want to start doing their initial public offering. So becoming a public company. And so maybe Musk is looking for some way to do something impactful in the near term. And maybe the moon is looking like something that, that he can do something exciting sooner than he can do something exciting related to Mars. I don't know. What do you think? I think the probably unfair and least charitable interpretation is that after the movie, the Martian, he knew everybody was excited about Mars. And so he rode that wave and now everybody's thinking about the moon. And he's got a public offering coming up and he's got to pump that stock. And that's probably unfair, but that's like the least charitable interpretation. But as you said, we can't get into his head. So instead, let's just think about the science. First, tell us how feasible was the plan to go to Mars anyway? Not super feasible or, you know, so maybe he would have been able to get starship there. So I'm not going to dig too much into the rocket plan. But what really got me frustrated was this plan that we're going to have a self-sustaining settlement in 20 to 30 years, which implied that you were going to have a million human bodies on Mars way before we knew if that was safe or not. Why do you need a million for self-sustaining? Why is that a requirement? Yeah. So a million is the number that Musk came up with, not me. I guess he thought that a million was the number that you would need to have enough people to do all of the jobs that would be necessary to have a self-sustaining like economy and enough people to have enough genetic diversity. I would note that when we were doing research, we felt like a million was an underestimate for all of the different kinds of jobs you would need if you were going to have the kind of economy that would also be making things like computer chips, which you would need to keep a complicated habitat that runs on technology on an alien planet running. This is a really fascinating thing to think about because the number of people involved in your daily life is huge. The number of people who make pencils and make toilet paper and transport all that stuff the number of people who touch your life is enormous. But we've built our society that way. We've assumed that everybody's here and then we can transport stuff. If you intentionally built a society that had fewer choices of pencils and only one kind of toilet paper because you wanted to simplify it, you're saying even then you couldn't winow it down to less than about a million people? Maybe, but I guess you could say we want fewer medical specialists and stuff like that. But on earth, you can make some winowing because you can walk outside and take a deep breath and you don't have someone who needs to manufacture the air, for example. But there are some additional things that you absolutely have to have in an environment where technology is required to keep you from dying. Where you need a spacesuit in order to walk outside because otherwise the nitrogen is going to boil out of your blood and kill you. So you need, for example, somebody who can fix a spacesuit and somebody who manufactured their pair patches for the spacesuits and all that stuff. All right, but let's start with the pros. What are the advantages of going to Mars? Let's deal man this case. Right, yeah. Okay, so you wanted to know why is Musk excited about Mars? And it's because Mars actually has a lot of pros if you exclude the earth. So Mars has plenty of water. It's got lots of water at the poles. It even has a lot of water at the equator if you're willing to dig down a little bit. And this is cool science, right? We didn't know that Mars had water on it until pretty recently. That's exciting. I mean, we thought Mars had loads of water and that there were canals shuttling the water around for a while. But yes, once we dispelled ourselves of that illusion, yes, we did recently learn that Mars had plenty of water. Mars has some atmosphere and it has a lot of carbon dioxide. And that kind of sounds like a bummer as an organism that doesn't love breathing carbon dioxide. But plants like to breathe carbon dioxide. That's good news for our plants. And I like to eat plants. And I like to eat plants too. And you can break it up and there's oxygen in there, which is a guess that we do like to breathe. There's also lots of oxygen, hydrogen, carbon and nitrogen on Mars. Those are all good things that we can use for us and for our plants. The climate is okay relative to other places in space. So the equator at summertime is about 21 degrees Celsius, which is about room temperature. So, you know, that's okay. We can work with it. Still not sunbathing though. No, no, you're not sunbathing. And, you know, that 1% of Earth's atmosphere that we talked about, like that's still thin enough that you can't step outside without a space suit as we talked about. You would die. And it's got a day that's kind of Earth-like, so about 24.7 hours. So that's kind of nice. And it's got a red sky with blue sunsets. That's pretty cool. That's pretty cool. Yeah. Yeah. So it's got some pros. All right. We're doing our best here to make the positive case. That's right. That's right. But it also has some cons. So we've already talked about the fact that it's really far away. It also has only 40% of Earth's gravity and we don't know how big of a problem that's going to be for human muscles and bones. There's some reason to worry that that might not be enough for, you know, to keep, for example, moms muscles and bones strong enough to get her through labor. And that might not be enough for fetus to develop normally. We just really don't have enough data to answer questions like that. And what about childhood, right? Like what happens to a child who grows up in low gravity? Did their bones develop weirdly? Did they get cancer? Did something else happen? Yeah. Right. And we have, we've talked about this in past episodes, so I'm not going to be labor it. Too much folks can go back through our archive to find those episodes. But, you know, in my mind, we need to do a lot of additional research before we send a million people to Mars to figure out the answers to those questions. Which to be honest is one of the reasons why I'm sort of excited about this pivot to the moon. We could use it as an opportunity to get those data before we start sending people to Mars to do reproduction and stuff. We, you know, we could like slow down and make this transition a little bit more ethically. In what scenario is raising children in low gravity to see what happens ethical? Like how do you figure that out? So, okay. So if you slowed down and you decided in addition to the AI satellites that Musk wants to be making, which we're going to talk about a little bit later, you also tacked on a biological research station. You could start with a colony of rodents. And, you know, maybe you give those rodents a decade. And if the rodents all seem super healthy, maybe then you could let people bring their dogs. And maybe you could let some of those dogs have puppies. And if they seemed fine, you know, maybe you could very carefully monitor some pregnancies of humans. And if anything looked bad at any point, you could send those people back to earth immediately. But if the pregnancy seemed to be developing normally, you could, you know, let it progress and very carefully watch how things were going on the moon. And you could, you know, sort of scale up that way. But even in that scenario, you are experimenting on fetuses or on babies or on children. But I guess that's just standard protocol, right? We do that also here on earth when we're testing out new medications or new treatments, right? Yeah, right. And I agree, but I do feel like there's a gradient of risk. And if you've done a lot of experiments on animals, you can at some point say, we have reduced the risk to a point that we feel comfortable with. But I agree, you are still taking the risk at some point. Okay, so reproduction is tricky. What else is hard on Mars? Growing food is hard. So the surface of Mars is covered in a jagged dust called regolith. And that jagged dust also has a chemical called perchlorates. And those perchlorates mess with your thyroid and the hormones produced by your thyroid. And it messes up nervous system development in fetuses and things like metabolism in adults. And if you try to grow food like plants in that dirt, the perchlorates get sucked into the plants. And so we're going to have to be very careful about that. And we in general need to learn more about how we would grow food in space and how we would grow food in a way that would also like generate oxygen and create sort of like loops that would recycle our waste while growing food and closed loop ecosystems is what it's called. And we need more research there. All right, so jagged poison dust in everything. Bad. Yeah, and dust storms that kick it up and cover the whole planet in it for, you know, weeks, sometimes at a time, which is going to make solar panels a difficult way to power your settlements. I saw that in the Martian, yeah. You did see that in the Martian, which means we probably want to figure out portable nuclear reactors before we get out there, which folks are working on, but it's not quite ready yet. Although some of the rovers on Mars are nuclear powered. Yes, they are. So we have done nuclear power on Mars, which is amazing as a species like Wow. Yes, but so they're not nuclear reactors. They're like thermocouples or something. So they've got like a little piece of nuclear decaying material, which provides warmth and a little bit of energy. I think they often also have some solar panels coupled to the system. But this is not like a nuclear reactor that you can like turn up to get more energy and down to get less energy. It's not the kind of thing that could power an entire habitat. Yeah, it's more like a nuclear battery than a nuclear power plant. That's right. We have a whole episode on nuclear spaceships and nuclear power in space. Go check that out. Yeah, so that is like a sub sample of the many challenges we need to overcome to have a self-sustaining settlement on Mars. Let's not belabor the point too much. There's a lot of work that still needs to be done. I don't think we could do it in 20 to 30 years. But let's take a break. And when we get back, let's talk about the feasibility of Musk's new moon plan, his new lunar ambitions. All right, we're back and we are talking about Musk's lunar ambitions. Musk is now heading to the moon instead of Mars, or at least he's going to the moon first. He still plans on going to Mars. I noted in the last segment that I'm actually kind of excited because going to the moon first gives us some time to learn some good skills and practice with some technology before we go to Mars, which is a much more like dangerous far away place. Whether or not we'll make the most of this opportunity remains to be seen because it seems like Musk does sort of want to rush through things. But we could learn from this. Yeah, one of the big arguments in your book essentially is that we're not ready to go to Mars and we need to fill in a lot more steps to get there and experiments on the moon and in near earth are part of those steps. So in that sense, hey, maybe Musk read your book and he's listening to your advice. I doubt it. Highly doubted. But you know, if so, that'd be great. The moon does have some pros and this is what Musk is pointing out. He's pointing out that the moon is, celestially speaking, pretty close. It's 385,000 kilometers away and pretty much always the same distance away. That's pretty nice. Yeah, it's always available right year round. Yeah. And so you can get resupply ships there quickly. You can get medical advice almost in live time. Whereas Mars is so far away that there's a three to 22 minute communication delay, depending on how far away Mars is from earth at the time. And that also means that you can control robots from earth in pretty much live time. That's pretty great. In fact, I think about the surface of the moon sort of the same way I think about Antarctica. Because you can get to Antarctica, but you can't get there this afternoon. There's a few planes and a few boats. It takes a couple of days. And if you're in Antarctica and you need to get home like ASAP, you can't be home for emergency surgery that evening. It's a lot of planning. And so in the same way, yeah, you can get there. It's just not easy. With the Apollo 13 crew, things went wrong and they were able to get help and turn around and get back in time and everyone survived. And then in Antarctica, there was a woman who figured out that she had breast cancer. She was a doctor and she was able to do a biopsy. She realized she had breast cancer and she ended up getting saved by a rescue mission that was able to come towards the end of the season. Right? Do you know this story? Yeah, this is amazing. This is Jerry Nielsen and she did a biopsy on herself in Antarctica and started treating herself with chemotherapy. She was then evacuated, but they couldn't get her out very easily. Because you can reach Antarctica much more easily during some parts of the year than others. And so they sent a plane several weeks ahead of schedule in this crazy weather to bring her back and they were able to evacuate her back to the US for surgery. Yeah, so it's difficult, but you have some options. Whereas for Mars, you're just 100% out of luck. Although there was that one Russian surgeon who did his own appendectomy in Antarctica because he couldn't get out on time. Like that is pretty hardcore. I would just be dead. Anyway, all right. So the moon also has some cool stuff like silicon, aluminum, magnesium, iron, titanium, things that might be helpful for building stuff like solar panels. There's also helium-3 on the moon, isn't there? Yeah. You don't sound excited about that. Why not, Kelly? Everybody talks about helium-3 as a fusion fuel. Yes, and maybe one day helium-3 will be a helpful fusion fuel on the moon. I don't think it's worth digging through tons of regolith on the moon to collect helium-3 for nuclear reactors that we aren't quite using yet. Or don't know how to build. Or don't know how to build. But some people disagree with me. And quick primer there. Helium-3 is a fuel for fusion. Fusion is not a technology we've made to work here on the surface of the earth with all of our infrastructure. We might one day get it to work. And we might one day be able to do it on the moon. But helium-3 based fusion, although it has some advantages, is also harder to get to work. So we're talking about an extra hard version of fusion that we haven't made work here on earth yet. Even when we're doing the easy version. Yeah. Yeah. The moon also has lava tubes. And lava tubes are kind of cool because when you're underground, that protects you from space radiation. It also protects you from impacts from like, you know, space debris that might fall onto the, you know, surface of the moon and could maybe puncture your habitats. And temperature swings are a little bit less extreme in lava tubes. And speaking of those temperature extremes, let's go ahead and jump to the cons. Because the moon has a lot of them. I love how you put lava tubes as a positive. Like lava tubes. Like who wants to live in a lava tube? That doesn't sound like cozy or appealing or attractive to me at all. So like the fact that you have to put it in the pro category just tells you like, there's not a whole lot of pros in that category. No, no. I mean, I think it would be cool to go in a lunar lava tube to like explore once. But I wouldn't want to live there. No. I mean, I don't even like going in caves. I'm claustrophobic. I went in a cave once and I was like, I need to get out of here. And then once you read the story by the guy who like crawled into the cave the wrong direction and got stuck upside down. Oh, no, stop. Yeah. No, no, no. You don't want to see that story. Okay, moving on. Moving on. Moving on. So the temperature at the lunar equator swings from negative 130 degrees Celsius to positive 120 degrees Celsius. Wait, by the fundamental theorem of calculus, that means at some moment it must be room temperature. Yes. Yes, there is a moment where you'll be like, oh, that's comfortable before you either freeze to death or like overheat to death. Nice. Yes. So right, it could kill you in either direction, which is lovely. The day times last the equivalent of two weeks here on Earth. And the night times also last the equivalent of two weeks. Why is that two weeks? Is that because the moon is tidally locked to the Earth? Probably. How about you explain that physicist friend of mine? So the reason a day lasts for two weeks on the moon is that the moon takes four weeks to orbit the Earth and it's tidally locked to the Earth. And so what that means is that essentially it takes four weeks for the moon to spin relative to the Sun. And so that's why a day lasts for two weeks because relative to the Sun, the moon spins once every four weeks because it's connected to the Earth and it takes four weeks to orbit the Earth. Excellent. That's a long time though to be at negative 130 degrees Celsius. Or at positive 120 degrees Celsius. It's a long time to be at either of those temperatures. Sounds real bad. Another thing that sounds real bad is that if you are trying to create a self-sustaining settlement, then you are going to need carbon and nitrogen and phosphorus. And the surface of the moon is low on all of those things. Why do you need nitrogen and phosphorus? I don't like buy those at the store every day. Well, that's because Earth has plenty of those things and plants suck those things up. And you get those from plants. And if you want to grow plants, which you probably do because we like eating those things, you're going to need to bring tons of that stuff with you to create your self-sustaining settlement. And right now, probably the most concentrated source of carbon on the moon are the 96 bags of feces, vomit, and urine that were left behind by the Apollo astronauts on the surface of the moon. But those belong to NASA. So we can't use them as fertilizer. No, you are not supposed to grow tomatoes in Neil Armstrong's long lost bowel movements. Wait, so we need fertilizer to grow any food on the moon, which means we need to bring all that fertilizer with us. Yes, or you could. Like import it? You could import it. You could put it on a rocket or you could find it somewhere else in space and bring it from there to the moon. But the moon ain't got it. Like, there's some ammonia in the water at the poles, which we're going to talk about. Ammonia has nitrogen. And so you can get some nitrogen, but it's not going to be enough to create a self-sustaining settlement. It's not going to be enough to make up for the fact that you're going to need to grow a whole lot of plants to support people. So in the spirit of steel manning Musk's plan, has he elaborated or even hinted on how he's going to solve any of these problems? No, not as far as I've seen, but let's go ahead and dig into a few more of the things that are going to make living on the moon difficult. And then we'll get into some of the some of the plan that he has elaborated on so far. First of all, I want to note that those temperature swings are going to be bad for equipment as well as people. So building factories on the moon is going to be difficult. Another thing that's going to make building on the moon difficult is going to be that regolith. So just like on Mars, the moon has jagged regolith, but on the moon it also tends to cling. So the solar wind makes it electrostatic and it also makes it sort of levitate a little bit. And it sticks to stuff. And one, the stuff it sticks to gets a little bit darker. So it tends to absorb heat and make things overheat a little bit. We think that one of the Soviet rovers, lunacod, overheated because it got some regolith on top of its solar panels and then everything overheated. And it's super abrasive. And so the astronauts would complain that if they got it on like they had these little watches that also had their like instructions for stuff they were supposed to do for the day. And if they wiped the regolith off of it, it scratched it so they could no longer read what was written on their watches. And so that's also going to be bad for equipment. Also bad for humans. There's concern that if you breathe it in, it's going to scratch your lungs and cause stone grinder's disease, which essentially means you get scars in your lungs until you can't breathe anymore. Bad. Bad. The moon has pretty much no atmosphere. We call it an exosphere. It's like essentially a negligible atmosphere, although physicists would be like, it still exists. Buh, physicists. Well, there is a distinction there. An atmosphere is dense enough that the particles interact. They bounce off each other, etc. An exosphere, the particles are there, but they're such low density that they basically never interact with each other. Okay. All right. There you go. So they're there, but they're sort of negligible from the perspective of human health. You're, you can't breathe out there for sure. And there's no protection from cosmic rays. Absolutely. Yes. Right. Yes. So you are getting hit by all the radiation space has to offer. The moon has one sixth of Earth's gravity. So your bones and your muscles are probably degrading, which over time could be a big problem. But again, we don't really understand that very well. And the moon has water, but not, but not much, not much. And that water is very concentrated. So like, yes, there is technically some water all over the surface tied up in that regolith, that dirt that's all over the surface. But technically, concrete also has some water in it. And concrete is wetter than regolith. Concrete doesn't seem very wet to me. That's right. That's right. So you're probably not going to want to be extracting water from the regolith. Yeah. But at the poles, you have these areas where there are craters. And on the rims of the craters, you could set up solar panels. And that's great because you might remember that at the equator, you've got this two week stretch of darkness in the middle of the night. So that's probably not a great place for solar panels. But if you are at the poles, over 80% of the time you get sunlight at the poles, especially if you're up on these rims. So that's good for solar panels. And then inside of the craters, you get these areas that are permanently dark. And there's water inside of those permanently dark craters. That water has some stuff in it like methane, hydrogen sulfide, and ammonia. Are those good or bad? Well, you don't want to drink those, but there's some carbon in there. And some nitrogen in there. So those are things that you could extract and use. There's not going to be enough to sustain like a million person settlement with the carbon and the nitrogen in there. But you know, you could you could still use some of it. But once you extract it, then now you've got water to drink or you could break it up and you've got some oxygen to breathe at that point. But there's not a lot of water in there. So like, have you ever heard of Sardis Lake in Mississippi? No. Yeah, no one has because this is like a tiny lake that's not worth knowing about. What if we have listeners who live next to Sardis Lake and now you're insulting them? Okay. Well, I'm sorry to people who enjoy Sardis Lake. I hear there's bass there and I like bass a lot. But this is a human made lake that most people haven't heard of because it's nowhere near as big as, for example, the Great Lakes. And the amount of water that's estimated to be in all of the craters is 10 percent of the water that's estimated to be in this lake that most of us haven't heard of. So I see the point. Yes. So it's not a lot of water. So you're saying if you took all the water on the moon and put it somewhere in Michigan, it would be smaller than a lake nobody's ever heard of except for the wonderful people who live next to it. Yeah, it's Mississippi. But I may have used the wrong abbreviation in our outline, Mississippi. But anyway, yes, that's the point I was trying to make. Right. Okay. So there's not a whole lot of water on the moon. Not a whole lot of water on the moon. And these craters of eternal darkness, which is what we call these craters that have the water, they make up point one percent of the lunar surface. So a very small percent. And those peaks, those rims where you can put your solar panel, we call these the peaks of eternal light, which is overselling it a little bit because they've got light like 80 percent of the time. But they are one 100 billionth of the lunar surface. So about two tennis courts. And these are the best places on the moon because you've got, you know, water in the best places for solar panels. And the reason you want to know that is because this is probably where Musk is going to want to go. And I was watching a Chinese news channel and what they were talking about was, Hey, this is where we want to go. Do we have to worry about Musk going there now, too? And this is also where NASA wants to go. And so now you have this very small surface area that is where everybody wants to go. And, you know, this program that I was watching was saying, like, well, as part of this new space race. And so, you know, now we've got this new space race and everybody trying to go to the same places on the moon. And that is a little bit concerning to me in particular. All right. So there are a few places where you can get solar power 80 percent of the time. How does that reconcile with your physicist's explanation for why the moon is in darkness for two weeks of time? Oh, yeah. OK. Great question. So if you are at the equator, you get two weeks of night and then two weeks of daytime. But at the poles, the moon has a different tilt than you get with the earth. And so the sun sort of glances off of it in a slightly different way. And, you know, and on earth, you get like different day lengths at the poles than you get at the equator. And these rims also lift you up off the surface a little bit. And so you've got solar panels up on poles up on top of the rims. And in that way, you can catch the sunlight as it glances off of the poles about 80 percent of the time. All right. So solar power is tricky. There's only a few places you really want to do it. Fusion is maybe impractical even here on earth. What about good old nuclear power? We know how to do that. We've been doing it for decades. Can't we build small modular reactors and send them to the moon? Yeah, sure. Those portable nuclear reactors would be helpful on the moon as well. We don't quite have those ready to go to the moon yet to power like factories like Musk is talking about. But people are working on stuff like that and that would be helpful. And so I guess the question is, do we imagine that we could have a lunar city that would be self-sustaining in 10 years? I think 10 years is really optimistic because like, I mean, when you are talking about temperature changes that are like 250 degrees Celsius, I mean, the amount at which metal like expands and contracts at those temperature swings and like, you know, how difficult it is to get lubricants that don't like boil off at that high temperature or like freeze at that low temperature. There's just a lot of engineering challenges when you're working at those sorts of temperature swings. I think we're not going to overcome all of those challenges in 10 years. But, you know, we could start building something in 10 years and that would be kind of fun. All right. It does seem like this is a hard problem. But remember, SpaceX has done amazing things. What do you think is the best way to attack each of these problems? Like, what is our best case scenario? Like for nuclear power, we said small modulator reactors, that might be possible. What about the other challenges? What's the best case scenario for each one? All right. Well, so first I'll note that like, Starship was built so that you can move a lot of mass fairly cheap, right? And so they could get things like carbon, nitrogen, phosphorus, stuff that they need to the moon. It would be expensive. But they are maybe in a good position to move a lot of mass to the moon to make it more habitable. I mean, Musk talks about like daily launches or multiple launches a day, like really getting a pipeline up to the moon. Yeah, right. Okay. And if that happens, you could get some mass there. Again, I do think that would still be expensive, but let's assume that that can happen. So, all right, you could build factories in lava tubes, and that would protect you from the radiation, which, you know, you and I recently had a whole episode about how radiation is not just dangerous for human bodies, but also bad for our equipment. So you're definitely going to need to protect yourself from radiation. And does lava tubes also solve the temperature problem? If you're not on the surface, is it more reasonable? Yes, it is more reasonable. Yes, that results in milder temperature swings, if you're underground. And it solves a lot of the regolith problem, because as the lava went through, it fused the regolith. And so now you don't have a lot of dust that's going to be getting into your equipment and stuff like that. You still have the problem of needing to figure out how you like lower everything into the lava tube. You know, like we're not super experienced with moving around on the surface of the moon, and now we're like lunar spelunking. But like, that's kind of a cool problem to solve. And so working in the lava tubes could be, you know, cool. And like, if you could even like fuse the inside of a lava tube and put an airlock in there, like maybe you could create an environment where you could walk around without spacesuits, if you could, you know, create a pressurized environment inside of part of a lava tube. Maybe. Yeah. All right. Well, I don't want to go into a cave here on Earth. So caves on the moon don't sound very cozy, but they do sound better than the surface. I'll admit. Yeah. There are braver people out there than you and me. So yeah, that's right. That's right. Low bar. But exactly. Well, what about the water problem? I mean, the solar system is filled with water, there's huge chunks of ice just out there. Certainly we don't need to launch water from the surface of the earth climbing up the gravity well, do we? Nope, that's true. And a lot of the asteroid mining community has been excited about collecting water from asteroids and figuring out how to extract it from asteroids and then, you know, selling it maybe to the International Space Station, or maybe they could sell it to the Lunar SpaceX facility. And so water could come from other locations in space rather than pulling it out of our gravity well. That seems pretty cool. I mean, people buy like Fiji water because it seems like exotic. Now, like asteroid water, like, yeah, I've paid 10 bucks for a bottle of asteroid water. Yes. Yeah. I mean, that could be a possibility. But again, that's not something we're going to like figure out in the next few years. Agreed. Okay. That's right. So yeah, I mean, you could have a portable nuclear reactor that powers your factory inside of a lava tube. I can technically see solutions to all of these problems, not in the next 10 years. But yes, I could see a path forward. Again, not in 10 years. All right. Well, on that positive note, let's take a break and come back and talk about Musk's other dreams for AI satellites. All right, we're back. Daniel, I want to start with a question to you. What is an AI satellite? Why do you want an AI satellite? I think when he says AI satellite, he's thinking about all the data centers we're building to power AI because AI essentially is deep neural networks and neural networks are basically linear algebra, which rely on matrix multiplication, which means multiplying a bunch of numbers by another bunch of numbers. And that's much faster if you do them in parallel rather than doing them one at a time. And there are special chips, GPUs, which were invented for calculating very quickly how to draw blood on your screen for your video games. And along the way, invented hardware technology to very quickly do matrix multiplication because you also need that for graphics on your video game. And then AI companies realized, oh, that's also the same technology we need to do with the linear algebra inside of our neural networks. So now GPUs are basically AI chips, even though they were invented for video games, they found this other use. And I think now the market is just swamped by people using them for AI. So they shouldn't be called GPUs anymore. They should be called like AIPUs or something. I don't know. And so I think when he says AI satellites, he's thinking data centers in space in order to power AI. Okay, all right. So, yeah, so Musk has an AI company called XAI, which was recently acquired by SpaceX. I love that when Musk buys his own company with his own company. This feels like a scam. Yes, it feels weird. But anyway, he owns the world, so he gets to do what he wants. And so he's done that. These data centers, as I understand it, and you probably know more, are getting huge. Like hasn't, didn't Microsoft buy Three Mile Islands so they could use that nuclear power plant to run their data center? Absolutely. The thing that limits AI right now seems to be the available GPUs. Like the more GPUs you throw at these things, the more powerful they get. There's this scaling behavior where it just seems like going bigger means smarter. So everybody's trying to go bigger than everybody else. And there's a huge market now for these GPUs. And for memory also in these chips, which is why like computers are getting expensive and memory is very expensive and GPUs are hard to find because it's like one company in the world, Nvidia, that knows how to make cutting edge GPUs. Must be a good time to work at Nvidia. Yes. Must be a good time to own Nvidia stock. Yeah, right. Right. Okay, so why, why space? Like why move that all to space? Because that's got to be really expensive to do. Why not just keep doing that here? Yes. So we build these things in massive data centers here on the earth. And they take a lot of water to cool these computers because computers use electricity. And when you do calculations, they heat up. And so you got to cool them. So we use a lot of water to cool them. They draw a lot of power and they take a lot of space. There's environmental impact. Real estate is expensive. And so recently Musk has been talking a lot about data centers in space. And people have been talking about this for years, but mostly it was scoffed at. And now people are taking it more seriously. And so, you know, let me try to steal man the arguments for data centers in space. Why do people want to do that at all? Well, number one, there's power up there, right? If you have solar panels, then those solar panels see the sun much more often, like there's no clouds in space, right? If you are far enough from the earth's surface, then you can always be in sunshine. So solar panels can power you. There's more power in space. So there's that. The other issue is environmental impact. Some people argue like, why should we cover the surface of the earth in data centers? We should just put those out in space. Also, because there's like infinite real estate out there, right? You don't need to take up land that somebody was going to use to build houses. You just fill space with data centers. Space is really big. There's plenty of room up there. And so, you know, in terms of like scalability, that's definitely an advantage. You can flip some of the cons and try to make them pros. Like one of the cons is it's hard to get up there. So anybody who's ever like run a computing system knows you got to reboot the stuff. You got to repair the stuff. You got to get in there sometimes physically to fix things. And that's harder to do out in space. Remember when we fixed the Hubble, we had to like launch the shuttle with astronauts to do a spacewalk to fix the Hubble. It was a huge pain. So now you're talking about like maintaining a data center in space. But these guys flip it and they say, ooh, that makes it less susceptible to terrorists, for example, right? So it's like data sovereignty. You're out there in space. You own these computers where the law is fuzzy, as you've often said, Kelly. And so like if my data is out in space, then I don't have to worry about like the US administration trying to subpoena it, right? Because it's not in their jurisdiction. Maybe my lawyers say, what do you think about that argument? The face you're making tells me you're not persuaded. I mean, I think you're still supposed to register your satellite when you launch something it is the responsibility, I believe, of somebody because if your satellite smashes into something, they need to know who would get sued. And so I think someone is still responsible for it. And there is a nation that would be responsible for paying the bill if you don't pay the bill. And so I'm pretty sure that you're not in a legal gray area if you're out there. I'm not sure that holds up. I think the strongest argument is that eventually we're going to have space industry and we want to build stuff for space. And if you do that, it makes sense to build it in space. The idea is if you need to stuff for space, then why build it on the surface of the earth and then launch it. So if you need, for example, data centers on the moon, build them in space, have them in space, don't build them on the earth and try to operate them from the moon or then launch them. And so if you have some sort of self-sustaining space economy, then I do think there are arguments for building data centers out in space using materials you already have out in space, assuming you have people living out there in space who can maintain them and support them and all this kind of stuff. But it's a bit of a bootstrapping issue. And I think part of that argument is because earth's gravity well is so hard to get out of that if you were making the satellites, for example, on the moon, it would be much easier to get them out into orbit. Exactly. Relative to earth. Even if they bring launch costs down, right, building huge data centers in space would be very expensive. But it is possible to build them in space for use in space, eventually. Okay, so it sounds like Musk's plan is to build AI satellites on the moon and then use what he's calling a mass driver to shoot them out into space. Yeah. Which is interesting because he's a big Heinlein fan and this sounds very moon is a harsh mistress-like where they used a mass driver to shoot rocks using an AI towards the earth. But anyway, maybe I'm projecting too much. But anyway, so... Well, mass drivers are cool because on the surface of the moon gravity is much less. And so you don't need chemical rocket technology to escape the moon's gravity. You just need a big gun. And so a mass driver is just like electromagnetic rail or even a... Or even like a centrifuge that spins up and then throws things into space. That's pretty cool. Now that you've done a pretty good job of emphasizing all the positives, let's go ahead and give it the Kelly treatment and talk about some of the negatives of doing this on the moon. Yeah, so there are challenges to data centers in space. Number one is cooling. There's a lot of misunderstanding about how this works. People think of space as cold. And so, isn't cooling just free out in space? The problem is space is an insulator, right? It's a vacuum. The thing you have in your thermos, for example, that keeps your coffee hot or your beverages cold is a vacuum gap between the beverage and the rest of the planet, because it's hard for heat to go across a vacuum. And that means if you have something hot out in space, there's no air to blow across it to get heated up to carry that heat away. You can cool down in space, but there's only one way to do it, which is to radiate that heat away. So remember everything that's out there that has a temperature glows and that means that it's cooling, it's giving off energy. That also happens down here on earth. You have like a hot piece of metal, it's red hot, it's glowing, it's giving off that energy, it's going to cool down. But here on earth, we have two ways to do it, convection and radiation out in space. You only have radiation. So you need to build big radiators out in space or bring a bunch of water to run across your chips, but you already are short on water. So cooling is going to be extra hard in space, not extra easy. That's number one. That's number one. Then there's a question of the radiation. Our data centers here on earth run under the protection of our magnetic shield, right? The magnetic field of the earth deflects a lot of cosmic rays and the atmosphere which protects us from cosmic rays. Even still, data centers, as we talked about on a recent episode, have to correct for bit flips from cosmic rays. I had dinner the other night with a guy who runs the data centers for Nvidia and they have all this cool technology to correct for bit flips, which is frustrating to me because when they delete those bit flips, they're deleting physics information that could teach us about the universe. Calm down, calm down. I know. But somebody's got to generate that image of puppies playing poker or whatever. Anyway, this is harder out in space because you have no protection and radiation is bad for computers and what you're doing is running computers in space. And so you need extra hardcore chips, which we have not developed, or you need shielding, which means again, more mass. So this is harder to do in space than it is here on earth. It's a more important, more challenging problem. And then of course, the biggest one is maintenance, right? Something always breaks. You build something at scale and needs a whole team of people to keep it running. Nothing, even like the Golden Gate Bridge just stands there and works, right? It needs constant maintenance. Everything does, which means you need a team of people up there all the time or launching up there all the time. And it's much further away. Imagine you were in charge of maintaining a computer on a table in Antarctica. It would be really hard to do if you could never go there and fix it or if it was hard to get there. And so this thing is going to be down all the time and there are going to be people trying to fix it all the time. And maybe we could get better at building computers that didn't need so much maintenance, but we're definitely not there yet. Well, what about maintaining those giant solar panels? Yeah, exactly, right? Solar panels also are sensitive to radiation. So those things are going to get destroyed. They need to get replaced or they need to be more robust. Another disadvantage is it's further away. And so maybe if you don't care about latency, then it's not a big deal. But if you want like fast turnaround times to your calculation, you want to press the button and get the answer instantly, then you don't want to put your data center far away because that adds latency to your calculation. I don't want to wait for my puppy playing poker. And in terms of environmental issues, if you're building the stuff here on earth and then launching it like launching things into space is not great for the environment. So I don't actually know what Musk's plan is. Do you think that his plan is to build these things on the moon or would that be just like way too complicated to do? No, I think his plan is to build things on the moon. That makes a lot more sense, but it assumes that we have the capacity to do this on the moon. But yeah, it's a lot cheaper if you build these things essentially in space for use in space, building them on the surface and then launching them makes very little sense to me. But even still, you have to face the issues of maintenance, of radiation, of cooling. These are all solvable problems, but it makes it expensive and laborious. And I don't think they have been solved yet. But you know, SpaceX is an amazing company and they catch rockets with chopsticks. So let's not put anything past them. All right, well, we will have to keep an eye on this as the years and the decades pass and see what they do. And you know, in the meantime, if you're interested in more information on what it's like to live and work in space, A City on Mars is a pretty great book to check out to learn more about that. As is becoming Martian by our friend Scott Solomon, which came out today, which is February 17th. You won't be hearing this on February 17th, but you should definitely check out becoming Martian. And you should check out the prior two episodes on which Scott Solomon was a guest. And so while we think there are challenges to building a self-sustaining colony on the moon, it's not impossible. And it is worth pushing, but we should be realistic about when it's going to happen. Yes. And we should try to do it ethically and I will try not to be too much of a wet blanket at this point. So we'll end the show now. Have a nice day! Daniel and Kelly's Extraordinary Universe is produced by iHeart Radio. We would love to hear from you. We really would. We want to know what questions you have about this extraordinary universe. We want to know your thoughts on recent shows, suggestions for future shows. If you contact us, we will get back to you. We really mean it. We answer every message. Email us at questionsat dangleandkelly.org. Or you can find us on social media. 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