What Is Terraforming?

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Speaker 1: Okay, Daniel, how many times in your life do you think you've moved, like from one house to another so many times. There was one period when we actually moved back and forth across the Atlantic. I think it was seven times in four years. That's wild. Yeah, from California to Geneva and back. It was insane. Well, the hard part is when you need to do renovations right, Like if you're the home that you're moving into is not quite habitable, that's right. You want to get it just as you like it. You wanted to be nice and cozy, you wanted to be comfortable place to live. You want all those things right. And that's hard enough when the other place you're living is across town or across the country, or even somewhere else on the planet. Yeah, but now imagine if you had to move to a whole another planet. I'm not sure I can get my wife on board for taking the kids to Mars or to the moon or did you better it's a little further than Geneva. It's a time of it for the traveling in Switzerland, and I'm not sure how we'd find a contractor to do that work, Like, who's going to do the renovations of my lunar base Elon Musk. He's probably got a company already for it. So you five different kinds of flooring. It's called house X the flooring company. The flooring company. Oh perfect. Hi, I'm h and I'm Daniel. Welcome to our podcast, Daniel and Jorge Explain the Universe. I'm a particle physicist, but I like thinking and talking about all sorts of crazy things in science, and I make cartoonists and mostly I'm just crazy. I got nothing to say to that. You're totally a sane, a normal person, and yeah, I'm so not saying that. Um. And this is our podcast in which we take things in the universe and try to explain them to you, make them understandable. We don't want you to be intimidated by the fancy words and science. Who wants you to understand them so you can impress people of cocktail parties when they ask you what is the Higgs boson or how does something actually work? Yeah, we want you to imagine what it's like to travel the universe and to see all these amazing things out there. Today, we're gonna talk about living on other worlds, terraforming, terraforming. Is that like the ceramic thing that you make statues out of. I think if you want to make a really big planet size statue, then you could call that terraforming. Yeah. Wait, I think I'm thinking about terra cotta. That's different. Terra cotta. That's right. Can you build a planet out of terra cotta? Right? That would be the largest pottery wheel in the in the history of the universe. Yeah. So that's a big question is can we be an InterPlaNet hairy species? Can we can humanity live in multiple planets? That's right? And this this is a really important question because if we want to survive for thousands or millions of years, we can't keep all of our eggs in just one planetary basket. You know, one comet comes and slams in the Earth and kills everything on Earth. Poof, we're dead. But if we have people living on Mars and the Moon and you know, and somewhere else, then we could survive such cataclysm as a species. You mean as a species, not me or you individually. Like I'm not going to jump up there and catch the commet and save the planet or anything like that. But from the point of view of humanity. It seems like a really important project to get off this rock, get living somewhere else. Yeah, Or like if we ruling this planet, right, Like, if we mess it up somehow and Earth is no longer happenable, what's going to happen to humanity? We have to go somewhere else. And you make us sound like we're a bunch of kids making a mess in the living room or something like you don't have faith that we're gonna be able to take care of this planet. You think we're on a on the trajectory to climate doomsday, where more like little kids burning tires inside of the house, you know what I mean? Like that's an officially recommendation people, Jorge says, do not burn tires inside your house. Just do it in the backyard. Right, Generally that's a bad idea. Yeah, is that how you start your cozy family evenings? Let's go burn some tires outside? Um. Yeah, But this is even bigger than that. This is bigger than can we go to another planet? Can we establish a base on another planet? This is can we make another planet habitable? So you can live outside, you can breathe the air, you can run around, you can grow crops. So you meaning we can go to another planet and live there, but we would be in space suits and inside of some kind of base the whole time. That wouldn't be a lot of fun. That would not be a lot of fun. I mean, I think if you went to Mars and just build a colony, like you know, out of ships and domes and stuff like that, you'd basically be living on Antarctica, you know, be cold and dry and unpleasant, and you have to pee in a space suit all the time, and it would not be like living on Earth and be very hard to imagine millions or billions of people living that way on Mars right or anywhere else. So if you want to really want to establish non Earth population centers, you have to figure out a way to make the planet itself habitable without space suit. Yeah. So that's where the term terraforming comes from. And so we were curious to know how many people out there, including you, maybe knew this term. Yeah. So I went out in the street and I asked people, have you heard of terraforming? Do you know what it is? What does it mean? Is it possible? Here's what people had to say, I've heard the word before, but I don't actually know anything about it. Okay, I used the form like how the Earth got formed? Okay, No, I haven't heard terraform before. No, No, I have no terraform. I've heard of it, I don't know the meaning of it. Okay, um on another planet forming the environment or something like that, something along those lines. A right, is that like when you dig up the planet. I've heard of the term, but not the definition. What's your best guess what it might be? How the Earth forms or how any planet forms or good. Yeah, I have heard of terraforming. Terraforming is whole fully something when we can be a step three civilization. I forget the correct connotation. But you'll maybe get a lot of energy from the Sun and be able to use that to go and colonize another planet and make the human race become a multiplanetary species. Do you think that's realistic? No? I think we have way too much on Earth that we need to take care of still, and that it's a sexy idea, but I think that it's not gonna happen for some long amount of time. All right, So a lot of nose. Maybe I was asking the wrong question. I was asking people have they heard of terraforming, and most of the people, except for one very smart gentleman I had a lot of a lot to say about it, had never even heard of the word. Right. They're like, just not even part of something they think about or or talk about or wonder about. Right, So that's good. We can we can explain people what the word means. Nobody thought it was terra cotta. Nobody except for you things that has to do with pottery, That's right, very Chinese soldiers. Except for now. Somebody now is going to be listening to this podcasts. They're gonna come away with it that that's their takeaway, right, that terraforming is making an earth out of terra cotta. But maybe a more interesting question to have asked would have been like, do you think it's possible to turn Mars into a habitable planet? Right? That's I'm curious what people would have thought about that. But anyway, in another universe and another multiverse, I asked that different question. Do you think people would have known or thought it was possible or not? I don't know, but I'm always surprised to hear what people think. I would have would like to know what people think is possible if that's sort of a feasible project the humanity could pull off. I mean, man, massive planetary engineering, as you'll hear in today's podcast, folks, it's not a small project to undertake. That's a word, planetary engineering. The idea that you can change an entire planet. That's amazing, right, Yeah, And you know it's something people thinking about for Earth. Right. Geo Engineering is the study of, like, can we solve our climate climate problems by doing some crazy engineering, you know, like deflecting the Sun's rays or or you know, injecting things into the atmosphere or pulling CEO two out of the atmosphere, like these massive engineering projects as desperate measures to reverse climate change. It's gonna become center stage more and more, and then in the next few years, I think be cool to we get that as a degree, you know, in your diploma planetary engineer. Yeah. Well, you know, the more people burned tires outside or in their living room, the more we're gonna have to worry about this stuff and counteract it. So somebody's got to think about it. There's a lot of really fun papers about geo engineering. People have crazy schemes to try to cool off the Earth or I mean a lot of it sounds really risky to me. It's not like we really understand the way the atmosphere works. So trying to tweet it and twiddle with it, like dialing the knobs on the atmosphere, that scares me. Seems tricky. If you don't have a lot of faith in engineers, generally, I feel, well, you know, sometimes you have to put your faith in the engineers because you have a desperate problem. Right, But when it's a when it's a system that you know they don't understand, Like we can't predict the weather very well, right, so how can you predict what happens when you seed clouds or when you put huge mirrors in space? Like And that's a fine thing to do on another planet where you know you have a million year is to figure it out, or a thousand years to figure it out. Um, an infinite budget. But when it comes to Earth, our home less open to this kind of crazy experimentation. I would be very concous. We only have one planet and so you know we if we miss it up tinkering, it could be bad news. Yeah, exactly, Um, would you put the whole climate into the hands of engineers and say, hey, tinker away, see what happens. I think it'd be cool just to be be called the P you know, like Planet arr engineer. You just want the title, you don't want the responsibility. Ye say it part of com planetary Engineer pH D and P. Yeah. So let's get into it. So what is terraforming? What is what is the concept of terraforming? Yes, so, just from the word terror meaning earth and right informing meaning forming, it means take another planet like Mars or another planet and make it like the Earth, make it to be able to sustain human life, right, make it habitable, yeah, make it habitable, make it a place that you might want to go, right, right, But is it? So it's basically the concept of making it so that you can step outside without a space food, take a deep breath and enjoy the sun and the air on Mars, yeah, or any other planet. I mean, And that's exactly the kind of thing that happens in science fiction stories all the time. Right, they land on some planet, they set down, they open the door, they take a deep breath, and they go ah, yeah, yeah, smells pretty sweet on planet x y Z. But there's nothing toxic or dangerous when I breathe this air, right, Yeah, exactly exactly, And that's that strikes me as very unlikely. I mean, that would be wonderful if it happened, but it strikes me as very unlikely. But that's the point, is being able to step outside without a space, food and breathe and live. But is that the only motivation kind of to enjoy the outdoors in another planet or is there something more that you know, we can't physically live that many people inside of a base or inside of a constrained environment. Yeah, I think if you want to if you want to really spread across the planet, you've got to make the whole thing habitable. I mean, if you're gonna build domes and live inside domes, that's that's not nearly as fun, right, and it's it's constrained exactly. So, um, if you want to have agriculture that supports a large population, you can need to have plants growing, and so either you have to build a dome the size of the planet or just make the planet into a dome, right, eventually having domes impractical? Interesting? Okay, So let's get into the details and what does it mean to be habitable. For a planet to be habitable, like, what do we need to change in other planets to make it more like ours? Yeah? So you need an atmosphere. You need non toxic atmosphere with oxygen in it. You need to have enough water, right. Um, you need the temperature to be reasonable. Right. You can't be a frozen instantly or boiled to a crisp as soon as you step outside. Um. You also, and that's not even enough, right. You might think, well, that's a tall order, and it is, but even that's not enough. You need things like shielding from cosmic rays. Right. If you're a place where the radiation is much higher than it is on Earth, then you need to be protected. Having an atmosphere will do some of that for you, but it might not be enough. Um. So I'd say those are the basics. Water, temperature, atmosphere, um, and shielding from cosmic rays. Those are the four elements. It's a lot of things to get right, you know already. I mean, so it just seems like four things. But that's that's a big list of requests for your for the flooring company or whatever it is we're gonna hire to to renovate the Moon for us, Well, it's just four things, but it's four things the size of an entire planet, right, Like you, it's not about like changing in a little dome. It's it's an entire gigantic space that you need to have these, right, Yeah, exactly. And we have that situation on Earth, which is wonderful, but it's not like that happened overnight. You know, this is a billions of years process to get to where we are today, and now we're talking about engineering it and doing it in hopefully less than a billion years, right, So it's gonna be harder to do on another planet, or it didn't happen by itself in a shorter amout of time. Yeah, it kind of makes you think how precious it is the conditions that we have here. Yeah, exactly. Maybe we should review, like roughly how that happened on Earth, how we got to habitable planet on Earth. Earth was formed big ball of hot lavats that it's cooled down a little bit, but then it was dry and so as we talked about a podcast episode a while ago, um, we got water by having comets smashed into the Earth's surface. And comets are basically huge snowballs in space, and so we brought water in from outer space. We ordered it right on door dash or something. Can you deliver like a thousand commets tomorrow, Hey arrowhead, we need a couple of trillion gallons please, yeah, exactly. So that's where we got the water right from space comets um. And then life started, right, and life and produced some carbon dioxides. This is very very early life like microbes that could eat things like metals and rock and all sorts of stuff that existed on the planet Um and produced some carbon dioxide. And we also got some carbon dioxide by venting from volcanoes. So that's how we got our atmosphere from microbes and from volcanoes. That gives us an atmosphere that has a lot of carbon dioxide in it, right, But then we need the oxygen, and the oxygen came when microbes, actually cyanobacteria in particular, and then later algae and plants figured out how to photosynthesize. For the instance, this essentially is breaking down C O two into oxygen and carbon, right, and so some of that oxygen is released in the atmosphere. And see, you have huge amounts of microbes and algae and plank in the ocean doing this all the time, and the trees now doing this produced enough oxygen to give us an atmosphere that was breathable for animals. Right, So that's how we got water, we got pressure, we got oxygen. Yeah, And it's all sort of tied together, right. The living things are tied together with the things in the rocks and the things that came from out of space, and it all sort of mixed together too, and that's where we evolve. Right. It's not like these are the ideal conditions for any life. It's just that these are the conditions in which we grew up in and so that's what we need, right. That's right, And you're right there, all tied together. It's hard to get one without the other. You know. Having enough water helps you with all these cycles, and having the right pressure in the atmosphere helps keep the water on the planet, and caps keep the temperature right. And so it's a very complicated, delicate system, and it's very easy to throw out a balance. I'm amazed, frankly that we haven't screwed it up already. You know that it's lasted this long where we're well on our way. I think expectations are are not low enough. That's right. Too many people are burning tires inside. Yeah. Um, okay, so let's get into the then how you would do it and another planet. Let's get into the details of of peeing, not peeing, but peeing planetary engineering a whole other planet to be just like our cozy Earth. But first let's take a quick break. Al Right, So, how do we set up a livable situation on Mars so that we can do cartwheels in the grass and enjoy and take deep breaths and drink from rivers and raise our children care free? Right, that's the goal? Yeah, how do we change the planet in which we would die if we stepped outside, to one in which it would be nice to go out and take a walk. Right, We basically want to turn Antarctica into southern California. Right. That seems how hard could that be? Right? Well, we're well on our way for that too. Antarc global warming is the new Southern California. Yeah, so we're going to start with Mars because that's the nearest planet. Right, that's kind of the best candidate we have for maybe moving the entire species to Right, that's right, this is a ridiculous project, possibly potentially impossible, costing zillions of dollars and maybe taking zillions of years. But of the impossible destinations, we mightsidder, Mars is sort of the least impossible. So yeah, that's the one people people talk about a lot, the least impossible. Okay, so there's a sliver of a chance that we might be able to pull this off, yeah, exactly. And so to figure out whether this was possible, I actually made a call to an expert, professor Jim Castings at Penn State University. He was he knows a lot about terraforming and Mars. He's thought about this. And when I first called him up and I asked him, I said, is terraforming Mars possible? He said, just flatly no, I can't be done. I was like, well, that was a short phone call, right, it was gonna be a this will be a short podcast. Yeah, But then I said possible, no next time, thanks for tuning in. So he said no. He said he's an expert, he's worked with NASA. He's like no, yeah, he's thought about like you said no. But then I said, okay, what if I give you an infinite amount of money. He was like, okay, mab Yeah. So then he considered it as an infinite number of years and he said, okay, infinite amount of time and infinite amount of resources, then we can do it. Wow. So there's it's about the resources. When you say it's impossible, it's not um like it violates any laws of physics. Is just that we he didn't foresee how we would pull this off with the resources that we have. Yeah. Well, as you'll hear when we talk about this, it's going to be expensive. Right. So the first problem is Mars has hardly in the atmosphere, and the atmosphere is mostly carbon dioxide. Right, There's almost no oxygen on Mars. So problem number one is you need an atmosphere on Mars. Right, But an atmosphere you mean like a layer of gas surrounding the planet, because currently it doesn't have much of that. That's right, So that when you step outside you take a deep breath, you get a breath instead of like your lungs boiling um, which seems less comfortable. Right. I don't want to we adds for the resort that we're going to start on Mars. We don't want um, images of our guests having their lungs going inside out and their blood boiling into space. Right, yeah, like Arnold trash Negger in total recall. Yeah that was a documentary exactly. Yeah. Yeah, well he could when he goes outside of Mars and like his eyes bug out and yeah exactly. Um. And so that's one problem is the atmosphere. And connected to that is the temperature currently on Mars. I checked the web this morning. It's negative sixty three degrees celsius on the surface of Mars. Right, Chili chili definitely not Southern California standards. Right. And those two things are connected. Is it connected to the the fact that there is no atmosphere, you know, like vacuum is by definition kind of cold. Right, Well, there's that, I mean, but also there's nothing to store the Sun's energy. Right. The Sun hits Mars and and warms it up, but then the energy just floats off into space, right, It just radiates back onto space. But an atmosphere acts like a blanket, right, and so it keeps the Sun's energy on the planet. That's one of the reasons why we have global warming here on Earth is that we're thickening the blanket we have of carbon dioxide is keeping more and more of the Sun's energy. So Mars has almost greenhouse, right, Yeah, it acts like a greenhouse. Mars has almost no atmosphere, and so most of the energies bounces right back into space. So the fact that you don't have an atmosphere and you don't and you and you're too cold are connected, right, which is bad. Had an atmosphere, it could warm up, Yes, exactly. So one strategy for warming up the planet is to give it an atmosphere. Right. So for example, um, I asked the professor, I said, you know what if we um use the carbon dioxide that is on Mars. Because Mars has a bunch of carbon dioxide, It has a bunch of water, but it's mostly frozen in the ice caps, right, so in the polar caps. So there's these huge amounts of basically dry ice which is frozen carbon dioxide on the surface. And so people have been thinking what if we could melt that somehow? Right, what if you stick it in a microwave? If you can build a planet sized microwave, then I think all these terraformy projects will be easy. Um. But no, say, for example, you sent up a bunch of nukes, right, you nuked the ice caps on Mars. Yeah, vaporized all of it, right, and then you would have some gas in the atmosphere, right, And so that's sort of a step in the right direction. So you propose that to him, what do he say? The problem with that is that there's not enough. Right. Even if you did that, it would be like one of the carbon dioxide, you need to make enough pressure on the planet so that you could warm it up. Right, So you need some other source of carbon dioxide. Now, this is something which is in contention. Some people say, Oh, there's a lot of more carbon dioxide that's sort of buried under the ground, and as soon as you start warming it up, that carbondox will be released into the atmosphere and it's sort of be a runaway greenhouse effect. It has to already be in on Mars. Like, we can't bring enough CEO two, like we have. Our problem is we have two munch c O two. We can't just take it to Mars. No, we could, that's another solution, right, but it's easier to start with the CEO two on Mars. And some people think there's just not enough c O two on Mars, so that even if you melt the ice caps and warm up all the rocks, that you just won't get enough C two. But that's the point of contention. Nobody's entirely sure. But if there isn't enough CEO two on Mars, as you say, we could bring some in it. You could find some comets or some you know, asteroids that are mostly CEO two and just sort of nugs them towards Mars and crashed them onto the surface. Oh man, wouldn't that cause other problems? Well, I think you'd want to do that before you build your resort um otherwise, I mean, what problems would it cause? I don't I mean, it sounds sort of naive, But like, what's the danger with crashing an asteroid onto the surface of Mars? Like nobody lives there. What's the worst that could happen if we on other planets? Um? No, that's a that's a realistic approach. And this is what I meant when I said, like massive resources can Now you have to build a huge spaceship and you have to get it out there to the asteroids system, and you have to somehow like find an asteroid or nudge you towards Mars, and like this is already costing a lot of money. Now we're talking about asteroid wrangling. Yeah, exactly, that's another cool job description. Yeah, asteroid wrangling. You're gonna get a lot of PhDs. You're gonna be like Bruce Banner, You're gonna have like seven pH D so you can solve any problem. Okay. So so that's where the costs start adding up, Like to get the atmosphere we need, you just need this these huge engineering problems which caused the money for people to do exactly sign up for them, right, Yeah, but there's there's more problems, like say you could do that, so you can nuke them, pull the ice caps and you can get some c O two, and then you bring in enough asteroids and you get enough c O two to warm up the planet. Then you have another problem, which is that the atmosphere is then toxic because in order to get enough c O two to make like a blanket to keep the planet warm enough, you need a lot more c O two on Mars than you do on Earth. And the reason it's just that Mars is further away from the Sun and it's smaller, so it doesn't get as much sunlight, so it needs a thicker blanket. Right, So you need a lot more c O two on Mars and you do on Earth to get to the right temperature. The problem is if you put that much CEO two to the atmosphere, it kills humans. So humans cannot breathe that atmosphere like could and you just make up for it by adding more oxygen more oxygen. Well, for you don't want an atmosphere with too much oxygen because then everything it just ignites simultaneously. Um. And also oxygen doesn't have the same properties as CEO two in terms of warming. Right. Each of these gases have a very different behavior in terms of planetary warming because they act different in the atmosphere. So that's not just not possible to do just straight CEO two. Um. But then the people have some other ideas, like maybe we could bring in some ammonia, because ammonia is a really good atmospheric warmer. Um. But pneumonia doesn't last very long. Um. So then I asked the professor, I said, well, what if you had some other way of warming it? Right, instead of just using CEO two, what if you brought the CEO two up to a level where humans could breathe it, and you had some other technique for bringing up the temperature, like burning tires. Do you have a lot, a lot of extra tires in your life and you're desperate to get rid of Is that what I'm hearing here? You know what I mean? Like, couldn't you create heat another way? Yes? Planet, Yes, And so one other way is to just increase the amount a solar solar exposure, right, to get more sunlight onto Mars. So build a big mirror in space and just focus a bunch of energy onto the surface of Mars. You mean, like kind of like um, like little kids do with the magnifying glass and ants. Yeah, exactly, kind of focus more sunlight onto the spot where the planet is. Yeah, you know, like those little um camping ovens that are just aluminum foil, and you can put hot dog in the middle of it and focuses the sun's rays on and eventually your hot dog warms up. That's the scenario, except Mars is the hot dog. Okay, So, but you'd have to build gigantic mirrors. Yeah, the Mars has about half as much solar radiation as Earth. Does that means the mirror would have to be about the size of Mars right now, we're talking about huge planet sized mirrors in space, and you gotta get them right. You know, if you too much or too little, and all of a sudden all of your guests and your resort are freezing or fried up. Right, So you're really going to be trusting these pH d p s to to get this right into never fail right. This has to work forever and always right. So it's a it's a tricky task, and all of this is just to warm up the planet, right, Yeah, exactly, So you've got to bring into problem number one exactly exactly. Are you feeling less enthusiastic now, it's just like training on the thermostat you know, that's just the beginning of your problems. Yeah, So you bring in an atmosphere somehow, you warm up the planet right, and then what do you have? You have a planet has the right temperature, has enough CEO two in it. But you also want to be able to grow crops, You want to be able to breathe, right, so you need to produce oxygen. Now, I remember the way that happened on Earth was that we had basically algae and phytoplankton. And also it's a little green microbes that are capable of producing oxygen. Um, and that's cool, and we could do that again. We could just like launch a huge tub of of plants, you know, of algae into the new lakes on warm Mars and they could just we could wait for them to do their thing. We could just make Mars moldy. That's right, that's right, make Mars funky again. Um. Yeah, And that all sounds great, And you might be thinking that sounds wonderful because then we're using the power of microbes. They multiply fast, and they can spread all over Mars and we can green the planet. Um. So I talked to a microbiologist. Um. One of them is my wife, and I also consult consulted them Professor Heather Beans, she's at Arizona State University. And they tell me that agreason will estimate for how long it would take to produce enough oxygen is about a million years. Oh my goodness. Even if we put giant tubs of algae there, it would take a million years to process all that t O two into oxygen. You would take a million years unless you know, you want to add another degree and you want to do like plankton engineering and create some new kind of microbe that's better at producing oxygen. But you have take about a million years, and you know it took it took like ten of the six or so years on Earth. It was not a fast process. So what what's the factor? Do you just not have enough algae or do you see algae juice? You know, if you max out the number of amount of alogies you could have on Mars, it would still take a million years. So in your mind's eye, you have like the surface of Mars is covered with ten ft of algae or something or something. Yeah, I'm all right, let's go into the max algae scenario. Even in that scenario, it still takes about a million years. And the reason is that algae are not in the business of producing oxygen. It's not why they do it. They photosynthesize and but in that process they produce oxygen. They also use some oxygen. So the amount of oxygen that's like produced is spare, is not It's not a lot um And yeah, so there's sequestering some carbon. They're producing some oxygen, but it's not an efficient way to make oxygen. I mean, it's it's nice because the sort of runs itself, and it's historical because it's the way we did it on Earth. So that's nice and cozy, but it's not a very fast way to make a to make a planet have enough oxygen it and I want to talk about that some more, but first let's take a quick break. Okay, So then what can we do? Can we bring oxygen in other ways? Yeah? Well we could bring water, right, we could bring water in and we could split it, make the H two O into H and O and uh and use that oxygen. That would take a lot of time and a lot of energy, right, splitting water into oxygen and hydrogen takes a lot of energy. But hey, if we're building planetary sized mirrors and shepherding afterwards around the around the solar system that I'm assuming we have access to a huge amount of energy. So yeah, we could certainly do that. Meaning maybe grab another comment with water and crash it onto Mars. That's right, splash it now into your ocean of algae that you have, pumping away oxygen into your atmosphere like a cooking project. We have the splant here, just grab some comments from over here, some asteroids r here. Mix it all together. Yeah, yeah, it's a cooking project. Um. And even if you do that, even if you accomplish all of those things, you still have another problem, which is that Mars doesn't have a magnetic field, and the magnetic field is really important in shielding from cosmic rays. Remember, cosmic rays are just tiny particles from space and they're usually charged, and so a magnetic field will bend them. Here on Earth, we have a magnetic field, and it bends a lot of the radiation from space and protects us and also protects our atmosphere. Right, so let's assume that we heated up the planet and we created enough oxygen for us to step outside and breathe. We still have a big problem, which is that it would all just blow away, right, that's right. The magnetic field keeps the atmosphere from getting blown away from the solar wind and from other kinds of cosmic rays. And so we need to create a magnetic field for Mars. And the size of the planet, the size of the planet, and as um, as crazy as that sounds, it's maybe the easiest task of all the things we've talked about. Today, because you don't need to like go inside of Mars and like get the core spinning to give you a magnetic field, which is how we think we have a magnetic field on Earth. You just need to provide a magnetic shield. And that might be as simple as putting a huge magnet out in space between the Sun and Mars to provide like a you know, a bending so that the particles don't hit Mars. And if you can get the magnetic field a little closer to the Sun, you can create sort of a magnetic envelope or a shadow to protect the planet. Wait, is it the easiest problem that we have in this is creating planet size force field using a planet size magnet. That's right. If you had if you had to pick each of these tasks to solve, that's the one I would recommend pick because that one's easiest and cheapest. Also, if you've solved all these crazy problems, you might be able to make Mars habitable. That's right. So you build an atmosphere, you trunk in a bunch of CEO two, You warm a planet with this, mirrors, you seated with things that produce oxygen. You provide a magnetic field then you wait a million years. You forgot to wait a million years apart. Don't pack your bags yet, you're gonna put your underwear back in your drawer. People. Um, it's gonna take a long time before Mars is habitable, even if we started tomorrow. Um, and you know, we can get there earlier with various basis. We don't have to complete the terraforming to start living on Mars. But for the deep future, if we want humanity really have a home on Mars, to be comfortable there, to to have plants growing and crops and all sorts of things, really healthy ecosystem, then yeah, we gotta do the terraforming. And it's gonna take a long time. So there is this liver of possibility. It would just be really really expensive and might take a long time exactly. It would be expensive, it would take a long time. Um, but it's not impossible. So given infinite time and infinite resources, it is possible. And you know, on this show we talk about things that are totally impossible and things that are just difficult and expensive. And and I like when things are just difficult and expensive because then you can just say, well, pass it off to the engineers I'm sure they'll figure it out. Right, You, as a physicist, can just wash your hands, be like, it's not my fault anymore, that we're dying as a species exactly. If physicists our job is to move something from impossible to possible. The rest is details, right, That's that's what we really have the engineers for. You know, eventually there'll be an app. You know, you could just um uh, you know, terraform my planet with with your app or something. It will take five seconds. And who wrote that app? Engineers? Engineers and they made all the money. Okay, so and they deserve it. A lot of a lot more rich engineers out there than rich physicists. If you ask me, I was gonna say something, but I forgot you were going to say something, but you got distracted by the huge pile of cash you have as an engineer. Sorry, I was counting my gold coins. I forgot what you were saying. Okay, So that's Mars. That's maybe one of the closest and and maybe least sour impossible tasting of the options. But there are other possibilities within our solar system, or maybe outside our solar system. Right, that's right, There are some other places that we could consider living. For example, there's the Moon. Right, the Moon is even closer than Mars, and so from the point of view like getting stuff there and doing the engineering, it's even simpler. The problem is that the Moon is has a lot of the same challenges as Mars, but it's even smaller, so the gravity is is much much less, which means it would be really hard to hold onto an atmosphere even if you did all the work. You crashed a bunch of comments into the moon. Um, you warmed it up somehow with mirrors, and you give it a nice atmosphere, the atmosphere which is leak away. Right, there's not enough gravity to hold onto the atmosphere on the Moon. You have to be big enough. There's a size requirement, yeah, exactly, have to be big enough so that you have enough gravity to hold onto the atmosphere. Right. It's like you don't want to buy somebody a fancy new jacket. If it's they're just going to throw it away. And that's basically it would be like, if we build an atmosphere on the Moon, it's just going to float away into space because the Moon is not big enough to hold onto it, but at least you would have enough cheese. Right, That's that's right. It would be a fun party while it lasted, right. Um. But if you're looking for like a you know, thousands and thousands of years kind of solution, like you want to establish a human base there, it's just not really a good good idea. I mean, it might last hundreds of years, you might even get a thousand years out of it, but you need to continuously replenish the atmosphere because it'd be constantly running away from you, because it'll just float out into space. Yeah, exactly, and just be constantly farting out your life source into space. So the Moon your far back in right, your planet, all right, So that's moon, the Moon. What about other planets in the Solar System. Well, Venus is interesting because it has exactly the opposite problem, right, Venus Mars we talked about has almost no atmosphere. The Moon is no atmosphere. Venus is the other problem, has way too much atmosphere. Venus is like we're afraid Earth might be in a million years is it's covered in carbon dioxide and it's way too dense. It's like ninety times the density of the atmosphere on Earth, right, so you'd be crushed two, right, Yeah, And all that CEO two on that planet for all those years has really heated it up. So it's like four hundred and something degrees on the surface of Venus all the time, right, That's not just like during the summer, that's all the time. So the problem with Venus is the opposite. You need to get rid of some of that atmosphere and that will help Venus cool down. And so that's that's hard, Like how do you get rid of atmosphere. It's the opposite problem. You need to take out CEO two. Yeah, And so people have crazy ideas. They're like, well, you know some ideas like somehow get that CEO two sequestered, you know, fire bunch of stuff into the atmosphere of Venus like magnesium or calcium, or you know, bombarded with hydrogen so that it forms water or um, you know, with all sorts of other stuff. These strategies to try to get the CEO two out of the atmosphere onto the surface, which has its own problem. And there are other strategies like make huge scoops and scoop off the atmosphere, right, Like like just gather it up and scoop it off Like that seems crazy to me, Like you're going to build an enormous spoon, like, you know, dig into the atmosphere Venus. It sounds crazy, but reasonable people talk about this stuff. You're like, it's physically possible, So get to work engineers. Yeah, and then I thought, you know what if we could take some of the CEO too off of Venus and bring it to Mars. Or we could solve two problems at once, Right, what if you could crash Venus into Mars and create the perfect planet? Now you're going too far. Okay, we can talk about planet sized mirrors, but we can't talk about smashing them together. That's just totally impractical. Um. Yeah, so that's you have am there's a limit to your flavors of that's right. The other problem with Venus is that it rotates really slowly. A day on Venus is two hundred and forty something days on Earth, right, so you have like really really long nights and really really long day So that's a pretty hard way to live. So it to really live on Venus, you'd have to like speed up its rotation somehow, And people have talked about how to do that. Yeah, like if you wanted to get ready the atmosphere, you could build like a huge jet which punches, which pushes the atmosphere out into space, and that could act like, um, like a nozzle, right to speed up the rotation of the planet. Now this is I mean, it sounded crazy, but like, um, that's a real solution. Okay, So that's venus. Um. We have the opposite problem. Where else where else could we go? Maybe outside of our solar system. Yeah, one of the most promising things is not engineering a planet that's close by, but picking the right one. You know. It's like, don't choose from the cars that are available to you in your neighborhood. If none of them work, like, go drive thirty miles to find the right one, you know. And so one option is to look for extrasolar planets, right planets outside our solar system around other stars. And recently we have amazing technology to do this. We found thousands of them and just find one that has the right characteristics, that has the right amount of solar radiation, has an atmosphere, maybe even has liquid water, um, you know, and from that point of view that we'd be starting from a pretty good spot. It's not unlikely we could find one that has carbon dioxide rich atmosphere with the right pressure and the right temperature and liquid water that there's nothing unreasonable about that expectation. So that's more like terror finding than terraforming, right, you know what I mean? Like it's you're looking for one that already looks like ours. Yeah, and even in that scenar area, there of some big problems. Like problem number one is it's super duper far away, right, So it's gonna take a long time to get there, if if that's even possible. Um. And you have to figure out that it's a good destination before you get there, because you don't want to travel for a thousand years and then turn around because oops, you know, we forgot the shopping list or oops, went to the wrong place. Um. The other problem is what do you do when you get there? Right, you want to establish an ecosystem on the planet, and having enough CEO two and you seed it with lie if and it produces oxygen, even that is not enough to make like farmable land. Right. What you need then is soil. You need to cover the planet somehow with with dirt that you can use to grow plants, and that's complicated, right, getting the getting dirt to work, getting soil to work is hard. We don't even understand how it works. On Earth. You know, people are studding. It's not just dirt. Dirt is not just dirt, you I mean, you can't grow things and just sand, right, sand and water you need. Most of the soil that we have on Earth is basically decayed plants, right, is leaf litter and other stuff that has died. So now you've got to start that process on another planet. You have to somehow seated. You can bring some soil and you can put it out there and it'll grow and spread. But to get the right balance of all those microbes working in just the right way to support the plants that you need to feed your people, that's not an easy problem to solve. And you can't just like truck in a planet's worth of soil from Earth. Right, people on Earth are not gonna be happy about that, And that's expensive. So it's a hard problem to solve. Even when you get there. You can just go to home deep and by trillion bags of soil, that's right, It's just not enough soil to fill another planet. And so that's the kind of thing that would take a lot of experimentation and a lot of time, but it is feasible. Okay, So we learned that there are a lot of different flavors of impossible. That's right, hoping beyond hope. Yeah, yeah, they're not impossible, right, All these things could be done, and you know, these are the ideas we have now. And if we're talking about things we're doing over thousands or millions of years, you've got to hope that human ingenuity is going to come up with even better solutions, better strategies, new energy sources, ways to do this kind of engineering. So give us some time. I think we'll figure it out. Yeah. We might not be desperate now, but we might be more desperate later. Yeah, so throw another tire on the fire and uh, you know, make some plans to live on Mars. That really makes you think about how fragile our planet is. You know, like we're so lucky not to be like Mars, and if we're not careful, we're gonna end up like Venus, you know, totally uninhabitable. In either case. Yeah, you know it's good to have negative role model. Right, we see some pretty terrible examples around us of what happens when planets go off kilter Mars lost its atmosphere, Venus overcooked. It's so, we're pretty lucky to be right in this sweet spot, and we better take care of it because it's gonna be a long time before we are capable of making another planet be home to a substantial population. So the next time you go outside, take a deep breath and savor it. That's right. You're not likely to get that anywhere else. That's right. All right, everyone, Well, thanks for lifting this upbeat episode of Daniel and Jorge Explain the Universe. If you have questions about what we said and you want to hear more about it, send us an email at Feedback at Daniel and Jorge dot com. Or if you have another suggestion for a topic you'd like to hear us talk about, send it on over. Or if you have a question about physics or philosophy or dating or small mammals or whatever, just send it on over. Yeah, if you have questions about ceramics like terra cotta, don't ask us. We don't know anything about it. All right, see you next time. Thanks for listening. If you still have a question after listening to all these explanations, please drop us a line. We'd love to hear from you. You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge That's one Word, or email us at Feedback at Daniel and Orge dot com