Daniel and Kelly’s Extraordinary Universe - Can planets lose their atmospheres?

Episode Date: April 23, 2020

How do planets get atmospheres, and how long do they last? Will Earth one day run out of air? Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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On the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want or gone.

Hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast and the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. It's important that we just reassure people that they're not alone and there is help out there. The Good Stuff Podcast Season 2 takes a deep look into One Tribe Foundation, a non-profit fighting suicide in the veteran community. September is National Suicide Prevention Month, so join host, Jay, Jacob and Ashley Schick as they bring you to the front lines of One Tribe's mission. One Tribe, save my life twice. Welcome to Season 2 of the Good Stuff.

Listen to the Good Stuff podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Hey, Jorge, can you smell the spring in the air? The air dusty makes fresh these days. I think it's all those. drivers in quarantine? Well, you better enjoy that fresh smell while it lasts. Uh-oh. Is your particle collider going to create a black hole that sucks it all away?

Why do you always blame particle physicists for everything? Why would I not blame particle physicists? I mean, it's definitely not the Cartuda's fault if something happens. Point taken. But you know, the Earth is losing its air, but this time it's not actually our fault. Hi, I'm Jorge, a cartoonist, and the creator of PhD comics. Hi, I'm Daniel Weitzin. I'm a particle physicist, and I'm not responsible for the end of the world.

Not yet, Daniel. Not this time. Don't you have to give that disclaimer? Not this time? How many times are you guys expecting to enter? Well, it's sort of like running away from the bear, right? You don't need to run faster than the bear. you just have to run faster than your friend.

So I just need to be the second person to destroy the world, and then I'm basically innocent. I see, because that makes no logical sense. Well, helps me sleep at night, at least. No, I got into particle physics, specifically because it has almost no practical applications and therefore cannot be weaponized or anything like that. So I would be devastated if it ended up destroying the world.

It has no practical applications, but it does have practical implications. We'll see. But welcome to our podcast, Daniel and Horrible. Jorge, Explain the Universe, a production of iHeart Radio. In which we give you a tour of all the crazy, beautiful, nonsense, insanity that's out there in the universe. All the things that seem like they don't make sense until we explain them to you. Yeah, all the things out there in space and all the things here on Earth as well.

We try to explain them so you can understand and also kind of realize how precious they are sometimes. That's right. And we do our best to bring you to the forefront of scientific thinking. Because what scientists are wondering about is what we are all wondering about. we'd like to know, how long will the universe be around? What is everything mad out of end? How long can we rely on that fresh spring breeze? How long would it all last, Daniel?

These days, it kind of seems like not that long, but people are feeling optimistic. Before Mega Maid sucks it all away. But, no, you're right. I think that the L.A. air, I think, is the cleanest it's ever been, maybe, since the turn of the century, the last century. That's true. When we take our carefully socially distanced hikes and we get to a nearby peak, we can see like all the way up to Malibu. It's pretty impressive.

And so I think, you know, air is something that we probably all take for granted because we always had it. We have it all the time. And it's something we definitely need to breathe and to survive and which protects us from space. But people might be surprised to hear that it's actually kind of fragile. Yeah. I'm definitely pro-atmosphere.

I'm on that side of the debate, you know. But the thing that you realize when you're sort of standing up on the top of a mountain and you're looking at the curve of the earth is that the atmosphere is a time. tiny, tiny little layer on the surface of a huge ball. I mean, it's like one quarter of 1% of the radius of the Earth is our atmosphere. Wow. 0.5% of the radius. 0.25.

Oh, wow. So I've heard it say it's almost like a thin layer of paint on a bowling ball. Yeah, it's like the most delicate little envelope surrounding a globe. If you were holding the Earth in your hand, you probably wouldn't even notice it. You know, our oceans, for example, are like the thinnest layer of water on the surface of a planet. And the atmosphere is even more delicate. Right. Earth rocks. It's mostly rock. It's mostly rock.

A little bit of a shine to it and a little bit of air surrounding it. And that's different from other planets. You know, other planets like Jupiter, they're like mostly atmosphere. Other places. Yeah. Well, yeah, Jupiter is all gas. Well, at its core, you know, it still has a little bit of rock and there's some metallic bits down there. But the gashes part of it is, you know, it's a huge. huge chunk of it. So, yeah, Earth is a little bit different from some of the other planets. And so our atmosphere is especially thin and especially fragile. It's like a very delicate

toupee on the top of a very bald head. Well, I guess the question is, why do we even have atmospheres? And, you know, as you said, we look around the solar system and we see that other planets don't have them. They've actually lost their atmospheres, like Mars. Yeah. Mars used to have an atmosphere and now it's gone. And one sort of fascinating perspective on the universe is to imagine billions of years ago when Venus and Earth and Mars used to all be very similar. They had atmospheres. There's more similar surface temperatures. And now Earth is basically the only place you'd like to live. You know, Mars got super cold and lost its air and Venus got super duper hot and its atmosphere is super dense. Well, it kind of depends how hot you like

it, Daniel. Nobody likes it Venus hot. Except the Venusians. Yeah, exactly. I wonder what it's like for them to take vacations on the surface of the earth, you know. They bundle up even in Southern California. They're like, oh my God, this is so cold. Forget about it. But it's 900 degrees on the surface of Venus. They're like, wow, we can make snowballs with water. That's crazy. But yeah, so it's a big question. How does the planet lose its atmosphere? And I guess, by consequence, how will Earth lose its atmosphere? Yeah. Will Earth lose its atmosphere? Yeah, it's just another question that reminds you that on cosmic timescales, the solar system in the universe are quite dynamic.

The solar system didn't always look this way. The Earth won't always look this way. Other planets have changed. When you only look on a 100 years or 200 years time scale, things seem to move pretty slowly, and you might be confused and think that they're static. But things are changing actually quite quickly on a cosmological time scale.

Yeah. And so I think scientists have lots of ways in which we can lose our atmosphere. I mean, it's just this thin layer of gas hanging on by gravity onto our giant ball of rock. But recently there's been a study that has a new crazy idea about how it could all be gone. Yeah, it was a fascinating new idea, and it sort of adds to our understanding for how planets can get rid of their atmospheres and also sort of solves a mystery about exoplanets. Yeah, and so today on the program, we'll be asking the question, how can a planet lose its atmosphere?

You make it sound like it just sort of like put it down, walked away, and came back, and it was just gone. Have you seen my keys that were on the counter? Well, in terms of planetary scale, time scales, it is sort of possible, right? One day we could have an atmosphere next day, it's all gone. Somebody took it. That's right. And you're like, hey, Mars, you didn't use to have an atmosphere and then I lost mine. Did you steal my atmosphere?

That's another interesting question. Ooh, yeah. Can planets steal atmospheres from each other if they get close enough, you know, like a black hole sucking gas from a neutron star. Well, maybe we should keep our social distance from Mars. That's right. That's right. Planetary distancing. Yeah. And so as usual, we were wondering how many people out there in the public knew whether it was even possible to lose your atmosphere or even possible to lose it in the way that this new study says that we could.

And so I asked questions, but in a sort of a new way. UC Irvine's campus is closed and we're all staying home to stay safe. And so I reached out to the internet to ask for volunteers to people who are willing to answer random questions from a scruffy-looking physicist. In the internet, they don't know you're a scruffy-looking physicist. Did you get more responses this way? You know, my avatar on the internet is the drawing you made in which you made me look pretty scrappy-looking. So I think it's a fair representation. Oh, man, Daniel, I am so insulted that I did not draw that avatar of yours.

It was another cartoonist. No, my avatar is the one that you drew. I have one also from Saturday morning breakfast cereal that I use on Gmail. Oh, I see. On social media, it's your drawing of me podcast. To some people, you profess your favorite cartoonist is me to other people. It's a different cartoonist. But anyways.

I've been cheating on you with other cartoonists, yes. Anyway, I reached out to these folks online, and here's what they had to say. If you're interested in volunteering for a future round of internet random questions, write to us at questions at danielanhorpe.com and volunteer. I think next time maybe you should just pick up the phone book, if you have a phone book. if they mean exist these days, but pick up something like a phone book and just dial random numbers and see and ask this question. Right, because we all love telemarketers.

And this is even better than telemarketers. It's telemarketers that make you feel ignorant. No, it's a telephysicist. It could be a trade-off. You're like, hi, I'm a physicist. If you have any questions about the universe, I will answer it right now. But first. All right.

Well, here's what people had to say. Yes, given the fact that Earth's atmosphere isn't doing so great at the moment. Absolutely, they can. our magnetic field that encompasses the earth protects our earth from the sun's radiation, solar wind. And solar wind would blow the atmosphere away. If we didn't have the electromagnetic field around the earth, then we would have no atmosphere, similar to Mars.

I believe they can lose their atmosphere if they're too close to their sun. I don't know, really. It depends who was living there at the time. I think definitely, yes, can be caused by an external, can be a supernova, or not asteroid or internal might be losing your magnetic field. I mean, I know that we are constantly losing gases with outer space due to atmospheric escape. But whether we could lose the whole atmosphere, I'm not so sure about that. I'm not sure how that would work.

I definitely think so. If we know anything about the Earth is we have like a core that's causing us to have a magnetic atmosphere and that protects us from like the solar winds and we have like theories and ideas of how that atmosphere started but I can definitely see you know a situation where on a some certain planet the core stops and the magnetism field stops and elements of the atmosphere can just be blown away by a sun's wind like a solar wind yes I certainly think it's possible for a planet to lose its atmosphere um Mars I think lost its atmosphere once it's cool or a lot of its atmosphere once it's cool down and the magnetic field fade, then the suns blew a lot of the atmosphere away.

Yeah, absolutely. Mars lost its atmosphere. Yes, a planet can definitely lose its atmosphere. Right, some pretty good answers there. Yeah. A lot of people had different ideas about how we can lose our atmosphere. Yeah, and these are all our podcast listeners. And so they've probably heard us talking about magnetic fields and solar winds and Mars.

Are you saying they cheated? No, I'm saying I'm proud that our listeners have learned something about astrophysics and space physics and that they, you know, have absorbed some knowledge. They are better educated on average on these topics than your random UC Irvine undergrad. Welcome to Daniel and Jorge University. The only university is still standing these days. But what I was interested in and was surprised by it was by how people knew about all the different ways that we can lose our solar system. So maybe let's start with that, Daniel. Let's walk us through.

What are some of the ways in which we can lose our atmosphere? Well, the first way that people talked about, and the first thing that probably comes to your mind, and the way that we've talked about a lot on this podcast is that it can just get blown away. Like, the Earth is surrounded by this ball of gas and it's held on by gravity. But there are winds out there in the solar system

that can help sort of sweep away particles from our atmosphere. Sometimes it's hard to remember that, you know, we're just a giant ball of rock floating in space. Yeah. You know, and that the air that we breathe, our atmosphere isn't attached to us. It's just hanging on by gravity. So if something comes over and blows it away, we could lose it.

That's right. And this isn't like, you know, a hurricane blowing the wind to knock over your ice cream or anything, most tortured analogy ever. The wind we're talking about here is the solar wind. And the solar wind is not like the motion of the air on Earth. It's a stream of particles and radiation emitted by the sun. And so it's mostly protons, but it's also high-speed electrons and other stuff. And what happens when these particles impact the Earth's surface is that they can knock off particles of gas.

Because these things hit at really high speed. They hit it like a million miles per hour. It's like 0.1% of the speed of light. And so it might knock the atmosphere particles and then throw them into space and then we'll lose them? Yeah, exactly. It's like a big billiard ball hits another one and they both go flying off into space because it has a huge amount of energy and it shares some of that energy with these particles. of our atmosphere, and then they both have enough energy to escape. Okay, so that's

not good. And so that can happen, like, if there's a solar flare or something, or just it can happen any time? It can happen anytime. It's happening all the time. Now, during solar flares, it can happen much more dramatically. But we have a shield, right? We have this, like, literal force field

in space that mostly protects us from this method. And that's our magnetic field, because most of the solar wind are charged particles. Protons and electrons, they're ions. We're not like being shot by neutral atoms of hydrogen. And that means that when they hit a magnetic field, they bend. That's what magnetic fields do. And so our magnetic field tends to deflect a lot of the solar wind. It's like we have a little envelope and the solar wind bends

around us. But I heard there's a problem with polar winds that like that might make them vulnerable. Yeah. Well, the magnetic field is not a perfect bottle, right? We have north pole and the South Pole and the magnetic field lines come out from the North Pole and go down to the South Pole. And when a charged particle reaches a magnetic field line, it tends to bend left or right depending on its charge. But they can move along the field lines. And so what happens is that some of them get blown out into space, a lot of them, but some of them get funneled along those field lines up to the North Pole and the South Pole. And that's what causes the Northern Lights and the Southern Lights, is energized particles hitting the atmosphere and making it glow. So basically,

the North Pole and the South Pole get a lot more of this cosmic radiation. You can get these plumes of gas leaving the atmosphere on the North Pole and the South Pole. Leaving, wait, leaving the atmosphere? Yeah. Just like when, you know, the solar wind, it hits the atmosphere, blows off particles. Most of the Earth is protected

because of our magnetic field, but it's like we have these weak spots in the North Pole and the South Pole. And then, so there's gas leaving the Earth, but then it doesn't come back? It doesn't come back. You get these big plumes of gas. And that's because you get really high energy particles hitting our atmosphere there

where we're not protected and knocking particles off. And then we lose them forever because the earth moves on. Wow. The earth moves on. Yeah. And so you take these pictures, you can see during solar flares especially, but all the time you see these plumes of gas being leaked at the north and the south.

You know, like if we were the death star, the north pole and the south pole is where you would want to send your X wing because that's our little weakness. Maybe we are, maybe we are the empire, Daniel. Maybe we are the bad guys. Everybody grows up to be their parents, right? Just like the rebels will grow up to be, to build their own death star. And then they'll realize we're just like our father. Welcome to Daniel and Jorge process Daniel's daddy issues. But there's a bit of a controversy here because, you know, some people think, oh, our magnetic field protects us. And that makes sense for all the reasons we just talked about. It deflects the particles. Some other scientists, though, say that maybe your magnetic field actually sometimes it bends particles towards the planet. And it ends up focusing it. Like, catches a huge larger swath of the solar wind than you otherwise would,

like your profile is much larger, focuses all those to shoot down near the poles, and you end up losing more atmosphere on these polar plumes than you would otherwise. So there's a little bit of controversy. Oh, I see. Hmm. Of whether or not the atmosphere is good for us. No, the atmosphere is definitely good for us,

but there's a bit of a controversy about whether the magnetic field is, in the end, protecting us or helping us lose our atmosphere. I think most scientists think it's protection, but there is controversy and discussion in the field. Wow. In the field, but then bum, and you know, we should specify that Earth has a nice magnetic field, which we think mostly protects us. But if you look nearby to Mars, for example, Mars doesn't have a magnetic field. And Mars is totally vulnerable to solar winds. And every time there's a solar flare, there's a huge flux of particles, and it blows off a lot more of Mars's atmospheric. Wow. All right. Well, it sounds like there are a couple of ways in which we can lose our atmosphere. And there's one more way and then actually some pretty interesting dynamics that can happen depending on the size of your planet. So let's get into that. But first, let's take a quick break. kids gripping their new Christmas toys.

Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal glass. The injured were being loaded into ambulances. Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and Order Criminal Justice System is back.

In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Well, wait a minute, Sam, maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot.

He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them.

I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Imagine that you're on an airplane, and all of a sudden you hear this. Attention passengers, the pilot is having an emergency, and we need someone, anyone, to land this plane. Think you could do it? It turns out that nearly 50% of men think that they could land the plane with the help of air traffic control.

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Join us as we talk to the leading expert on overconfidence. Those who lack expertise lack the expertise they need to recognize that they lack expertise. and then as we try the whole thing out for real wait what oh that's the run right i'm looking at this thing listen to no such thing on the i heart radio app apple podcasts or wherever you get your podcasts all right daniel so our atmosphere is not a given in our planet we can lose it it can blow away by solar winds but it can also sort of have explode out of our planet. Yeah, we're talking about impacts from like tiny little particles.

The solar wind is a huge stream of tiny little particles, but you can also get hit by bigger stuff, right? Like an asteroid? Yeah, you see shooting stars at night. That's a huge, big rock hitting our atmosphere. You know, what happens when you throw a rock into a pool is you make a splash. And so if you throw a big rock into our atmosphere, you make a splash and some of that splash drifts off into space.

Oh. Yeah. So it's another way we can lose our atmosphere. we get we could get pelted by rocks and those blow the atmosphere away yeah you can think of the atmosphere is like a cushion or like a force field against rocks right because it slows them down it heats them up it it immolates them before they hit the surface which is nice and that's why earth doesn't have a lot of craters because we have this atmosphere but it's not forever right we can use it up if earth gets hit by a lot of asteroids then it depletes the atmosphere unless you're

lucky or unlucky enough to get hit by comets which are actually like cosmic snowballs that can deliver water or gas when they melt in your atmosphere. And, you know, this is not a big factor today, but we don't know. Some people think that this was a big factor in how Mars lost its atmosphere, not just to the solar wind, but also to a lot of impacts. Well, I guess it's kind of a runaway effect. Like if you start to lose it because of one thing, then you have less protection against the other kind of.

Yeah, exactly. And the estimates are that Mars lost more than two-thirds of its atmosphere due to either. either impact or the solar winds, and that solar wind effect is called sputtering by the scientists. And so early on, they think that that's the dominant way that Mars lost its atmosphere. But today, there's actually something else going on on Mars. All right. Well, it sounds like these are kind of maybe the basic ways in which you can lose your atmosphere. But there are sort of two new ways maybe that people are thinking about, right?

Like, depending on the size of your planet. And one of them is kind of this interesting new study that maybe planets can eat their atmosphere. That's right. Yeah, we'll get to that in a little bit. But it turns out that the way that Earth is losing its atmosphere is mostly not due to polar wind or solar wind or meteor impact. It's something. Wait, wait, wait, wait, wait. So we are losing our atmosphere?

We are losing our atmosphere. Yes, absolutely. Really? As we speak. Right now. We have less atmosphere right now than before we started talking. Oh, man. See, I knew we were just blowing hot air. here, Daniel. And that's making it worse because the reason Earth is losing its atmosphere is that

it's literally just boiling off the planet. Wow. Okay, so step us through here. So if the planet is too small, you're saying, the atmosphere can just gradually boil away. And that means kind of like when you put water on the stove, the particles that are on the surface, they just get energized and they fly away. Yeah. Is that kind of what you mean? Yeah, just like, you know, water evaporates from a puddle, right our atmosphere can just evaporate off into space what is keeping the atmosphere on the planet is only gravity so if your planet is too small like the smaller your planet is the harder time it has hanging on to its atmosphere like why does the moon have no atmosphere well it's basically just too small to hold on to anything even if we created an atmosphere and shipped it to the moon and put it on there it would just

drift away in you know tens of years really it would just drift away it would just yeah it would hang out for a bit, but eventually it would all evaporate. Yeah, well, the same laws of physics that apply to you have also applied to little particles and just like how it's easier to leave the surface of the moon, take a run and a jump, and you could float off into space where that's... Is that true? Okay, well, not really. I mean, you'd have to be super strong.

You have to go like two kilometers per second. So I guess if you're Iron Man, maybe... If you had any athletic ability, Jorge, you would be able to jump off of Mars. No, I'm talking to the moon. Mars would be much harder to do. jump off of the moon might be possible. But the same is true of little particles, right? Earth is much better holding on to little particles than Mars is than the moon is, right? And Jupiter much, much better. And so if your planet is too small, it's just hard to hold on to your atmosphere.

Interesting. But I guess, you know, even if things float away, why wouldn't they just come back due to gravity? Is it because we're moving through space and we sort of miss it? Well, once things float away, they don't come back. I mean, that's what escape velocity is, right? Escape velocity is, how much speed you need to essentially be able to neglect the gravity of that object. Like if you shoot a satellite off into space and it reaches escape velocity, it doesn't come back. Like the Voyager or whatever isn't just on its way back. It's got some trajectory away from us and the gravitational power is just weakening and weakening and weakening. And in the same way, if a particle has enough velocity to leave the Earth's atmosphere, there's no reason for it to come back unless it gets deflected.

It bounces off the moon or, you know, that alien mother ship that's a orbiterer. been orbiting quietly for the last few years. Okay. So then it would help to be heavier because then you can keep more of your atmosphere. That's right. So lighter planets tend to lose their atmosphere. And we also tend to lose different gases at different rates. Like we lose hydrogen on Earth and helium, but we don't lose oxygen nearly as much because oxygen is heavier. And so that's why... So it falls to the bottom. Yeah. Well, that's why Earth has very little hydrogen naturally occurring in our atmosphere because more of it bubbles away. Whereas the heavier stuff,

you know, xenon or oxygen or neon, that stuff is heavier. And Mars doesn't have the gravity to hold on to the same kind of things that we can. And so water vapor, for example, on Mars can easily reach escape velocity, whereas Earth has enough gravity to hold on to it. Oh, I see, because Mars is smaller than Earth? Mars is a lot smaller than Earth and it has weaker gravity. And so today, the dominant process for how Mars is losing its atmosphere is not sputtering. It's not the solar wind.

It's actually just being boiled off. Wow. And Mars is still losing its atmosphere at a rate of like one and a half kilograms per second. Wow. We need to kind of like put a lid on it. I guess so. I mean, if we're ever going to move to Mars, we need to provide a new atmosphere. And then we need to somehow prevent it from just leaving, right?

We talked about terraforming, needing some sort of like huge new magnetic field to prevent sputtering, to prevent the solar wind from blowing that atmosphere away. We'd also need to sort of just keep it somehow on there, yeah. Although, of course, the process of atmosphere loss on Mars is very slow. So your new atmosphere would stick around for a long time before actually getting blown away. And so I don't know if you've seen space balls or remember it, but they have this huge planet-wide envelope to keep their atmosphere in place. No way. Spaceballs foresaw this situation 30 years ago.

Space balls could foresee the future. I was trying to come up with a quote from the movie, but I can't. I don't know it that way. That's ludicrous. That's ludic. There you go. And so that's how Mars is losing. atmosphere now, right? These hot gases basically just boil off. The same thing is happening here

on Earth. Oh, so we're losing our atmosphere. That's shocking news. Every, every breath we take, there's less air. Yeah. And it's not at a tiny rate. Like, Earth is losing three kilograms per second of hydrogen and 50 grams per second of helium. I see. And so this adds up, you know, to like tons and tons of gases every year. Per second, three kilograms. How much is that? Like a teaspoon? No. A kilogram? No, a kilogram is a liter of water, right? Oh.

So we're losing three liters of water's worth of hydrogen every second? Every second. It's just boiling out into space. Wow. Why are people not more alarm? Well, you know, we have a lot of hydrogen. Unfortunately, we're a big planet. And it turns out that by the time we lose most of our hydrogen, other things will have

happened. Like we think in about a billion years, By the time we've lost significant atmosphere, you know, the sun will be 10% brighter than it is today. And at that point, we'll have other big problems. For example, it'll heat the planet up and the oceans will boil and break into water vapor. And probably all that hydrogen will also get lost into space. Oh, right. We're talking a billion years until we have to worry about it.

Yes, exactly. You don't need to worry about your kids having enough air to breathe or your kids' kids, kids, or your kids, kids, it's a lot of generations. I think in that time scale, wouldn't we evolve? probably to breathe differently, right, in a billion years? The biology would probably adapt. Yeah, perhaps we would. Perhaps we could breathe differently or perhaps we will have just left this rock and explore the universe and found other places to live.

Or we could do, you know, geoengineering and protect the earth from getting hotter and fabricate new hydrogen, new oxygen and, you know, curate microbes that can produce more oxygen as we needed or something like a billion years is a long time to figure this stuff out. Yeah. I mean, who knows, maybe in a year, physicists will end the planet all by ourselves with plenty of air to spare. You sound like you're rooting for that option. I am not rooting. I'm just trying to prepare.

Go, physicist, go. I'm just trying to prepare mentally, Daniel. So it doesn't surprise me. I see. This is a classic relationship technique. It's called pre-assignment of blame. Oh, there you go. If this happens, we agree it's your fault.

Then we don't have to argue about it. Oh, I see. You're a big fan of that, right? I'm a big fan of pre-assignment of blame. blame, yes. Well, if it does happen, we'll blame you. Yes, you can come to my house after I destroy the Earth and shout at me. With plenty of air to shout at you, fortunately.

Right, so boiling off gases is basically what's happening here on Earth now, and it's now the dominant process on Mars also because the atmosphere is much more dilute there. And so this is something I wasn't even really aware of, that this is a big factor in how you can lose your atmosphere. Yeah. And so all of this is if your planet is small or too small to kind of have enough gravity to keep it all in. And so other things can happen if your planet is too big. Yeah. So we'll get into that. But first, let's take a quick break.

December 29th, 1975, LaGuardia Airport. The Holiday Rush. hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal, glass. The injured were being loaded into ambulances. Just a chaotic, chaotic scene.

In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and order criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly and now I'm seriously suspicious. Well, wait a minute, Sam.

boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate.

Well, according to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Imagine that you're on an airplane and all of a sudden you hear this.

Attention passengers, the pilot is having an emergency and we need someone, anyone, to land this plane. Think you could do it? It turns out that nearly first. 50% of men think that they could land the plane with the help of air traffic control. And they're saying like, okay, pull this, until this. Pull that. Turn this. It's just, I can do it my eyes close.

I'm Manny. I'm Noah. This is Devon. And on our new show, no such thing. We get to the bottom of questions like these. Join us as we talk to the leading expert on overconfidence. Those who lack expertise lack the expertise they need to recognize that they lack expertise. And then, as we try the whole thing out for real, wait, what?

Oh, that's the run right. I'm looking at this thing. Listen to no such thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. All right, Daniel, we're losing our atmosphere, but it's not something to worry about. It's happening very slowly, maybe in a billion years, but by then, we're losing our atmosphere. we have other things to worry about. But there's a new study you were telling me earlier that talks about what can happen

if your planet is too big because apparently you can lose your atmosphere in other ways if you are too big. Yeah, well, first of all, the title of this study is awesome. It's called Why Planets Eat Their Own Skies. And we'll include a link to the study in the episode of information

so you can read it for yourself. Oh, it's from Stanford. Yeah. Not a bad school I hear. It's a junior college, so I don't know. I hear they give PhDs to cartoonists. well so yeah they do it's been on a down cycle ever since then said the berkeley graduate of course man go cow go cow go cow how many football games have you been to at cal oh i've been to a lot

yeah no football games are a lot of fun we're a little encapsulation of the old beta rivalry right here on the oh man it's scientists versus engineers it's cal versus stanford what else bananas versus non-binanas that's right we satisfy all of your rivalry needs here on the program No, lots of people contribute to this study, not just from Stanford. It was led by Edwin Kite at the University of Chicago. And they noticed something really interesting. They noticed that when we see other planets in other solar systems, which is now this thing we can do, right,

is we can look at planets going around other stars, and we can measure two things about those planets. We can measure their mass and we can measure their radius. And that tells us, like, roughly what's going on in those planets. We can tell, like, how dense they are based on the mass. mass and the radius information. And so the radius we can tell by looking at it, but the mass we tell by their orbits or something?

Yeah, you can tell the radius by like how much of the stars light is being blocked. And you can tell a planet mass by how much it makes its star wiggle. Oh, I see. Oh, this is a study of exoplanets out there in space, not just our solar. That's right. And what they noticed is that they see a bunch of planets that are sort of earth-sized, and they see a bunch of gas giants, but there's kind of a gap. Like you go up to about like three times the size of the Earth, what they call, you know, Neptune-sized planets.

And then bigger than that, there's like a gap. There's no like planets in between like Neptune size and Jupiter size. And naturally you would expect sort of like, you know, a big continuum. You expect like a smooth distribution that there are planets everywhere. Yeah, like big rocks, smaller rocks, meaning rocks. But you're saying that the... There's a gap there. There's this cut off before the gas giants and after sort of the Neptunes or the super-Earths.

And they were trying to understand why. And it turns out that they came over with this cool explanation that if a planet gets big enough, but not too big, and it has a rocky surface, then that rocky surface is like lava. So you have like lava flowing on this hot surface. Then it can actually absorb its own sky. The gas in the atmosphere gets sucked into these oceans of liquid magma. Because of the gravity?

Well, the gravity is certainly part of it, right? But that's not happening on Jupiter, right? Jupiter also has a lot of gravity, but still has vast atmospheres of gas. But it's something about this chemical interaction between the liquid magma ocean and the gas in the atmosphere. Oh, I see. And you're saying it doesn't happen on Earth because we don't have magma and lava on our surface because we are, what, not hot enough or not heavy enough? Both. You need the liquid magma on the surface.

And then you also need more gravity because you need the pressure. You need the gas to be like squeezed down onto this liquid magma. that can sort of force it into it. And so they find that basically these planets just eat their atmosphere. That stops them from growing bigger. Like the reason Jupiter is so big is because a huge part of it is its atmosphere, right? On Earth, 0.25% of the radius of the Earth is the atmosphere. Jupiter is like a third or a half of Jupiter is atmosphere.

Okay, so you're saying that we see planets out there and they get bigger and bigger in terms of the size. But we don't know how big the rock inside of them are, but you sort of say, see the size and so at some point if the earth suddenly grew in rockiness in size you're saying that at some point the first of all the surface of earth would turn into lava or that's not necessary no that is necessary for this to happen and i think in these larger rockier planets it's hotter right there's more pressure because there's more gravity and so the surface is more likely to be magma and then that pressure squeezes the gas down onto the surface of that magma and basically forces it in and like gets it dissolved in into the lava i see into the like it traps yeah so you get like

carbonated lava like sparkling lava sparkling lava wow it's like mountain dude but literally mean out of mountain there's this whole new beverage trend you know sparkling water and sparkling this and sparkling that nobody yet has thought about selling sparkling lava well there you go that's a new market yeah Exactly. And so basically it forces, you know, the gravity and the pressure forces the gas into the rock. And that keeps the planet from really growing in size. Because when you're a planet, you get to count the extent of your atmosphere as part of the planet. Right. And so where are the planets that are just bigger rocks? Why is there a gap? Or are they saying that suddenly at some point, planets grow in size because of their atmosphere, not because of the rock? Yeah, planets grow in size because of their atmosphere. Like the way to get a really big planet is to have a small icy core and then accumulate a lot of gas. If you accumulate too much rock, then you can't really grow anymore because you can't attract any more gas.

But why can't I just have a Jupiter-sized rock floating around the solar system? You know, I didn't say you couldn't. I mean, go ahead. Like, do whatever you like. It's a free universe. You can. You can. You can.

But, you know, there's just not that much rock. like most of the material in the solar system is gas. So if you want to get big, you got to include that in your budget. So like if you just look at rocky centers, they maybe taper off. Like they get bigger, bigger about the size of Earth, three times the size of Earth, and then you don't see them get bigger. Yeah. But you do see plants get bigger because then they start to accumulate atmosphere.

Yeah, that's right. But if your rocky core is too big, then it can prevent you from growing a big atmosphere because it can suck it into the liquid magma in the core. I see. All right. So probably the bigger planets we see out in the universe, they don't have a rocky center bigger than ours. They have smaller rocky nuggets inside, but they're bigger because of the gas. And adding enough gas can turn any rocky object into a gas giant. We don't really know the size of the rocky cores in some of the big gas giants in exoplanet systems, but most of the volume is gas.

That's why they are bigger. And if you look at the internal structure of Jupiter, it has a rocky, icy core, but it's pretty small. You know, it's not enormously vast. After that, it's like metallic hydrogen and all these things because of the high pressure and then vast, vast clouds of just gashes hydrogen. And that's the way to go. But you know, there's even still a lot of questions about how planets like Jupiter form. Like, how do you get so much gas accumulated? You need to have some sort of rocky core that forms rapidly enough that has time to accumulate

all that gas because the gas is pretty light. And so it takes a while for gravity to gather that together. So we're still learning about how all these planets form. You know, and in 10 years, we could have a lot of new ideas for how any of these planets form. And I think we talked on another podcast about, like, should Jupiter-sized planets form always in the outer solar system or only in the inner solar system? You know, can they move back and forth? And so we're learning so much about our planet and other planets and how it all puts together just by studying other solar systems. It's a fascinating time.

And so they call it eating your atmosphere, or eating. your sky because in a way you're sort of like absorbing the gas, right? Like if your rock is big enough, it'll sort of absorb the atmosphere. Yeah, it sucks it into itself and prevents it from getting bigger. It's like you sucking your stomach in, right? It keeps you from looking larger. I don't think that works in real physics, Daniel. I'm surprised. All right. Well, it sounds like we should once again be lucky that we are just the right size, because if we were heavier, if the earth was bigger, we wouldn't have an atmosphere. Yeah. Or, it would have a, we were smaller, we wouldn't have an atmosphere either.

Yeah, it's just another way that the Earth seems to be at this weird sweet spot, right? We're just the right distance from the sun. We have just the right amount of atmosphere. We have just the amount of stuff to hold on to that atmosphere, but not too much. We're like far enough away from the center of the galaxy to not be fried, but not so far away, that there's no planets out there. And so it's amazing how many ways we seem to be lucky, you know, and it raises questions about how many other planets are out there that could have as many lucky factors.

Yeah, you can't be too big or too small. You've got to be just right. All right, well, we hope you enjoyed that. And maybe when you go out there and breathe this new, clean air that we're all enjoying because of where we are these days, think about how precious that breath of air is and how if we were a little bit different in this planet, we wouldn't have that nice fresh air. And count your breaths because you only got about a big, billion years left to enjoy them.

Depending if Daniel ends the universe or else. And thanks to my friend and colleague and geologist Steve Davis for sending me this study and the idea for this podcast. Yeah. If you are a physicist out there listening to this program and you see a fun paper, send it to Daniel. I will definitely look forward to hearing it from him about it. But we want to hear about all your thoughts and all your questions.

So if you have a question about anything going on in the universe or a study you see on the internet, please write to us at questions at Daniel and Jorge.com. We do love our listener mail. See you next time. Thanks for listening and remember that Daniel and Jorge Explain the Universe is a production of IHeartRadio. For more podcasts from IHeartRadio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys.

Then, everything changed. There's been a bombing at the TWA terminal, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, terrorism. Listen to the new season of Law and Order Criminal Justice System. On the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit.

Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want her gone. Oh, hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast

and the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. I'm Dr. Scott Barry Kaufman, host of the psychology podcast. Here's a clip from an upcoming conversation about how to be a better you. When you think about emotion regulation, you're not going to choose an adaptive strategy which is more effortful to use unless you think there's a good outcome. avoidance is easier ignoring is easier denial is easier complex problem solving takes effort listen to the psychology podcast on the iHeart radio app apple podcasts or wherever you get your podcasts this is an iHeart podcast