Daniel and Kelly’s Extraordinary Universe - Are there other Earths out there?

Episode Date: December 25, 2018

How many liveable planets are out there, and can we reach them? Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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So before we could see other planets in our solar system, we saw Saturn, Jupiter, Mars, but we didn't know if there were other planets out there. That's right, and we only had this one example, so that's all we could draw. And of course, we wondered, how unusual are we? Could we possibly be the only solar system with planets around it? It seems ridiculous. But as far as we know, we're the only system with life in it as well. So these are deeply intertwined questions like, are we unusual in the universe,

or are we typical? And until a few decades ago, we didn't know at all. We had no information because we couldn't see outside our solar system. But now, that's all changed. We are not alone.

We may be alone, but there are other planets out there. Hi, I'm Horace. Jorge. And I'm Daniel. And welcome to our podcast. Daniel and Jorge explain the universe. In which we take the universe and we search through it for tiny little bits of fascinating knowledge that we can download into your brain. The question today is, are there other Earths? Are there other planets out there where we could potentially move? If we screw this one up, do we have somewhere else to go, right? Do we have a backup plan?

If or when we screw it up. When, it's definitely a when. Yeah. When we ruin this place, when we trash this hotel room that we've been birthed in, do we have another place to go? Is that feasible at all? Yeah. Or is the Earth like this super rare gem that's just perfect for life?

And it's nowhere else in the universe. Can you find a planet like the Earth? Right. And I don't know which message is sort of more valuable. Like, do you want to tell people, hey, look, the universe is filled with opportunity to encourage exploration of space and the scientific discovery that comes along with it?

Or do you want to encourage people to treat Earth as unique? Like, this is the only place we could ever live. So take care of it, people. Don't be so silly. You know, like, it's sort of like a parenting choice, you know? How honest are you with your kids

about whether you could actually buy them more food, you know? Yeah, like, you want to tell people they live in a hotel or in their house? Because people probably take care of their house a little bit better, right? But if you know it's a hotel. That's right. Yeah. Then, you know, you're throwing chairs and having big parties and, you know, like your typical rock stars.

I mean, I know that's how you travel, Jorge, isn't it? You leave a trail of trashed hotel rooms behind you, right? Yeah, yeah. No, totally cartoonist lead a wildlife. Everybody knows that. You're just drawing from experience. Anyway, apologize for my pun there. Yeah, but we're wondering how much do people know about other planets out there? Like, what the probability was that there are other planets that we could potentially go and live on. Yeah, are people walking around under the assumption that we have a backup plan? There's no big deal.

And we could just bail on this one and head to the next one. Or are people operating as if this is the only jewel in the universe and we've got to take care of it? So Daniel went out there as usual and asked people on the street, do you think there are other Earth out there? Here's what they had to say. Well, it might be. there might be so far that we cannot reach them. Oh, certainly. I mean, the universe is big enough that it's bound to happen at least once.

Definitely. I think the universe is too big to just have us as the special, like, higher beings. People seem to have a lot of confidence that there are other places for us to live. Almost everybody said there are definitely other planets out there. Yeah, I guess everyone's comfortable with the idea that the universe is humongous, and so therefore we can't possibly. be the only nice blue planet out there. I know, and I like the idea that the universe is humongous because it is, and I get that

it suggests that we shouldn't be unusual, but it certainly doesn't provide a rock-solid argument. I mean, that's not an argument that this is a big place, and therefore there must be more of us. Until you've seen another Earth, until you've discovered life somewhere else, you don't know if we're the only place that has these features, right? It could certainly be that we are the only place where life could exist. I mean, if there was only one place for life to exist in the universe, that would be the place people ask that question, right?

Right. So I feel like people make that argument, but there's a missing piece there, right? You have to know that other Earths can happen. You have to understand the mechanism for their formation or something to argue that there really are other Earths out there. Yeah. I wonder if people are just conditioned from watching so many sci-fi movies, you know, that show other planets, and, you know,

coincidentally, all those other planets look just like Earth because those movies were filmed on Earth. Mostly around Los Angeles. Hey, look, this planet looks like Malibu, yeah. Well, that's so weird. There's terrible traffic on this planet, oh, my God. We're so steeped in science fiction, and they're being aliens and other planets,

I wonder if it's just kind of a given that there would be other planets. Or maybe science has done a good job of, like, teaching people how vast the universe is and how many stars there are out there. Yeah, I think NASA's usually done a great job about announcing their discoveries and what they've learned to the general public.

So other science agencies can definitely take a page out of their playbook. But also because it touches on something which people are curious about, you just need to look up at the sky at night and you can see the grand mystery that is the universe.

Other fields of science, you know, chemistry or even particle physics, are not quite as accessible because their mysteries don't jump in your face every single evening when you look up at the stars.

So I think it connects to people's imagination a little bit more and also to the, there, you know, this idea the humanity is on a trajectory that we're, you know, we haven't flatlined or plateaued or peaked, that we're just, you know, we've explored Earth and we've developed

technology and that clearly the next step is to go out into the stars and to spread this disease slash blessing that is humanity into other places in the universe. It's like our manifest destiny or something. I think there's a lot of that feeling. And maybe that comes from science

fiction, or maybe just comes from the human need to build and develop and explore space. And so I think people want there to be these other Earths out there. So I think part of this feeling that the universe might be filled with Earths is a hope, right? It's a hopeful thought. Nobody wants to say, no, I think

the universe is a desert, and we are the only oasis, and we're probably going to die here today. Like, you know, it's a... I was mostly young people I was talking to, so maybe they're just a more hopeful crowd. So maybe we should talk first about what we want in another

Earth. Like we're shopping for new homes. You usually decide how many bedrooms you want and all that stuff. So let's make our shopping list for like what another Earth should look like. What do you look for in a planet Jorge? You know, Wi-Fi is pretty up there. Power outlets.

Not freezing temperatures. Right. Breathable air. Yeah. That might be too much to ask for. I think number one should be like a rocky surface, right? We don't want to live on a gas giant, right? where you're just like, it's a dense clouds all the way down to like a surface of molten rock or something in the core.

We need something that has enough rock on it that we can stand, right? So rocky planets rather than gaseous planets, I think is item number one on my list. Yeah, because, you know, even the plants we have in our solar system, the aid that we know about, there's only one of them that we could actually hang out in, right? Yeah, I think we could probably make Mars work, right? Mars is on the edge of that zone. It's a little too cold. Really? But, you know, if we were able to terraform it and add.

At an atmosphere and a magnetic field, then it would probably warm up pretty nicely. Things we don't know how to do yet. Things we don't know how to do yet. But I'm hopeful, right? I'm hopeful that humanity can do these kinds of things, right? This is accessing the positive side of my personality. But yeah, most of the planets in our solar system are not well suited for life at all. Yeah.

So you need a rocky surface. You need to be the right temperature, right? You can't be too close to the sun so you get blasted by fire every day. You can't be too far away, so you're freezing all the time. right and where that zone is depends on how hot your star is if your star is much much hotter than our star then you have to be further away obviously and if the star is cooler then you can be much closer to the sun which would be really amazing like imagine being on a planet that's closer to their star

so then even though it's not any hotter the star takes up a larger portion of the sky you could have like a huge red sun in the sky if your planet is going around a red dwarf oh you mean it could feel the same way as here but our sky would be like basically a big red circle. Yeah. Or if you have a much, much hotter sun, you could be further from it. So even though it feels like the same amount of heat and radiation, the sun in that world would be just like a dot in the sky.

It would look the same size as, you know, almost any other star. But it would be just as warm. It could be like a, we could see that's just another star, but it could be the one thing that's warminess. Yeah, exactly. So the experience of being around another star with the same amount of heat captured by the surface could be a very different experience

from the point of view what the sky looks like. Anyway, so we want a planet with a rocky surface. We want about the right temperature, right? We'd like some atmosphere, certainly. We need a magnetic field. Why do we need a magnetic field? Because we've got to protect ourselves from solar radiation, all sorts of other stuff.

Remember, magnetic fields bend particles. And so if you have some dangerous high-speed particle coming from space, you need that magnetic field to deflect it. Earth has a really nice magnetic field, which gives us like a shield against cosmic radiation. So you absolutely need a magnetic field. That's kind of a necessary condition for a planet to be habitable. Yeah, space is filled with harmful radiation.

You can't go out into space without serious radiation shielding, and our planet has radiation shielding. It's the atmosphere combined with a magnetic field. Absolutely. So a planet without a magnetic field would require us to, like, constantly wear radiation shielding, or build a radiation shield. or you can actually construct a radiation shield

using a strong magnet you put out in space. That would be pretty cool. But you definitely need some sort of shielding. And that actually rules out a huge category of places to live because the center of the galaxy pumps out an enormous amount of radiation because of all the crazy activity that's happening there, black holes and dense stars and all sorts of crazy stuff. We don't actually really understand

because the center of the galaxy is a hard place to study. But it's pumping out so much deadly radiation that even the planets around stars that are anywhere near there could not support life because the magnetic fields are not strong enough. So you have to be far enough away from the center of the galaxy also to be safe from that kind of radiation. Oh, your whole solar system could be in a bad neighborhood.

Yeah, there's entire swaths of stars that just because they're close to the galactic center could never really host life, you know, as we know it. Maybe some sort of super radiation hard life could develop there. People with thicker skin. That's right. people with thicker skins in bad sense of the humor. Well, this is a perfect point to take a break.

I'm Dr. Scott Barry Kaufman, host of the psychology podcast. Here's a clip from an upcoming conversation about exploring human potential. I was going to schools to try to teach kids these skills, and I get eye rolling from teachers or I get students who would be like, it's easier to punch someone in the face. when you think about emotion regulation, like you're not going to choose an adaptive strategy which is more effortful to use unless you think there's a good outcome as a result of it if it's going to be beneficial to you. Because it's easy to say like go you, go blank yourself, right? It's easy. It's easy to just drink the extra beer. It's easy to ignore to suppress

seeing a colleague who's bothering you and just like walk the other way. Avoidance is easier. Ignoring is easier. Denials is easier. Drinking is easier. Yelling, screaming is easy. complex problem solving, meditating, you know, takes effort. Listen to the psychology podcast on the IHartRadio app, Apple Podcasts, or wherever you get your podcasts. Smokey the bar. Then you know why Smokey tells you when he sees you passing through. Remember, please be careful. It's the least that you can do.

What's what you desire. Don't play with matches. Don't play with five. After 80 years of learning his wildfire prevention tips, Smoky Bear lives within us all. Learn more at smokybear.com. And remember, Only you can prevent wildfires.

Brought to you by the USDA Forest Service, your state forester, and the Ad Council. Have you ever wished for a change but weren't sure how to make it? Maybe you felt stuck in a job, a place, or even a relationship. I'm Emily Tish Sussman, and on she pivots, I dive into the inspiring pivots of women who have taken big leaps in their lives and careers. I'm Gretchen Whitmer. Jody Sweeten, Monica Penn, Elaine Welteroff.

I'm Jessica Voss. And that's when I was like, I got to go. I don't know how, but that kicked off the pivot of how to make the transition. Learn how to get comfortable pivoting because your life is going to be full of them. Every episode gets real about the why behind these changes and gives you the inspiration and maybe the push to make your next pivot. Listen to these women and more on She Pivots, now on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. So that's what we mean by another Earth. Like, is there another planet with the same conditions that we have here?

And so that's kind of the question. And so, but I guess the first question is, are there other planets at all in other stars, right? Like, we sort of take that for granted, that other stars have other little balls of rock floating around them. But up until a few years ago, we had no idea. no confirmation. That was just the hypothesis. That's right. And it's a really cool story. In fact, it has a really cool first chapter to it, which is that

only a few decades ago, they figured out how to look for these planets around other stars. And one of the primary ways, one of the first ways they did it is by seeing stars wiggle. And so, what happens is you have a planet going around a star and you think of, okay, there's

a planet, it's going around a star, and that's happening because the star is much bigger than the planet. So the planet orbits a star, right? That's mostly true. But there's a little caveat there, which is the gravity works in both ways, right? The star is pulling the planet and the planet is pulling the star. So what actually happens is not just that the planet is moving around the star, but the two of them are moving around their center of mass.

They're moving around this point that's between the two of them. So both of them move. So you can tell if a star has planets around it based on whether or not it's wiggling back and forth because it's getting tugged on by that planet. It's kind of like if you had, if you're swinging a rock and a string, even if it was a little rock, you would still feel that the pull of the rock, right? Like you would still sway back and forth as you were swinging it. Yeah, exactly. So they figured out how to do this and they started looking and they found planets.

But the amazing thing is they went back through historical data, like data from telescopes from a hundred years ago. And they found this evidence in ancient data. Like somebody in 1917 had taken, you know, careful data about the local. location of a star, and they had seen Wiggles. And at the time, people had been like, what's this? I don't know. I don't know. It must be something wrong, or it's noise in your data. Then they went back later and realized, this is beautiful data that showed evidence of an exoplanet, but it just hadn't been recognized at the time.

So we had this information 100 years ago. It was just ignored. It was just like not understood. Well, let's take a step back. Why is it so hard to see planets in other stars? You know, like in our solar system, you can see. Mars in the night sky. You can see Saturn. You can see the rings around Saturn. So you can see other planets that are in our solar system. But that's actually much more difficult to see that

in other solar systems, right? That's right. And think about what you're seeing when you look at that planet. Planets look bright in the sky. Why is that? Well, they're not little stars. They're not giving off light. They're mostly reflecting light. The same way the moon is, right? Why can you see the moon? The moon is just a dark rock. Why can you see it? You can see the part of it that It's illuminated by the sun. You can see the light reflecting off it from the sun. So moonlight is really just reflected sunlight, right? And all the light from Mars, for example, is light that started the sun, bounced off of Mars, and then came to Earth.

So the reason we can see those planets is because they reflect the light of our star. Right. And because they're not so close to the star, right? Right. You think about another solar system far away, then the planets are really close to that star compared to their distance from us. So, Mars is really far to the star compared to its distance from us. So you can see it away from the sun. If you look at the nearest solar system, the planets are really close to the star.

And so even if they reflect light, it's just a tiny little bit and it's basically included in the blob that comes from the star. We can't really tell them apart. Right. So like if you were to point a telescope at another star in the night sky, you would just get blinded by the light from that star that you were looking at, right? That's right. In your telescope, the planets look really close to that star

because the distance between them and the star is tiny compared to the distance between them and us. It's like if you look at another city through binoculars, right? You can't really see any details. You can just maybe see that it's there. Yeah, like it was described to me as, like, imagine that your friend was standing next to the world's brightest lighthouse, holding a little lighter, you know, or a little match, a little flame.

It would be like you're trying to discern that flame that your friend was holding from like 3,000 miles away. Basically, all you would see is the light from the lighthouse. You wouldn't be able to see that little flicker next to it. Yeah, and I think actually that's overly optimistic because plaintiffs don't give off their own light like a lighter does, right? It's like if somebody's holding up a rock next to a lighthouse, and you're trying to see that rock at night from 3,000 miles away

based on how much light it reflects from the lighthouse. Yeah, it's almost impossible, right? It sounds impossible, which is why up and to... until like 30 years ago when we didn't have the technology, there was no way we could have seen any other planets besides the one in our solar system. Well, directly, right, in terms of using telescopes to see that light and say, like, here is a picture of that planet.

That was impossible until fairly recently. But strategies to see them indirectly have been possible for a while, we just didn't realize it. Oh, I see. So you're saying that historical data that you heard about is basically we had like data to know that there were other planets and other stars. We just didn't know to look for it.

That's right. And to me, that's tantalizing because, you know, whoever that was in 1917, they got that data, they basically missed out on a Nobel Prize, right? Discovery of Exoplanes. And this data was sitting there in a library or whatever for decades. So, of course, then the question is, what other data is sitting in the library right now,

which is somebody knew how to analyze could reveal something amazing about the universe that could win you a Nobel Prize, right? It's out there right now. Everybody, stop listening to this, podcast and go to the science library and figure it out. Or maybe in your computer, Daniel, right? Like, there could be something in your data that you're not seeing.

Who knows? There certainly could be. There certainly could be. Anyway, to me, that's a fascinating wrinkle. When you look back and you see data from history that people didn't understand at the time what it meant. Okay, so that's the idea that it's really hard to look at other planets and other stars directly.

So the first confirmation that there were other stars out there came. indirectly from looking at how stars wobble, right? And also like how the light from stars changes, right? Yeah, so the first method was the wobble method, and it uses gravity to see how the planets are wiggling the stars. And the second method, it's called the transit method. And this is the idea, still you're looking at the star because it's all you can really see directly.

And you watch the star's light, and as the planet goes in front of the star, the light from the star should get a little dimmer. It's like a little eclipse, right? Now, you're not going to cover the whole star. The star is not going to go totally dark. It just dips by a little bit depending on the size of the planet. But if that happens regularly, right, you watch the same star for weeks and weeks, months, and years, and you notice a pattern, then you can deduce that there's a planet there.

And you can figure out what's its period. How often does it go around the sun? And you can figure out how big is it? What fraction of the light of the star is it blocking? But, you know, that it sort of assumes that the orbit of the planet, goes around in a circle that is just kind of like perfectly in the same level as we are. You know, like, you could have a planet going around another star, but it could be going like, you know, in a circle kind of perpendicular to us.

So you would never see it create an eclipse. But if it just so happens to be kind of on the same level as we, you would see it kind of passed in front of the star between us and that star. That's right. It has to pass between us and that star. You're totally right. But remember that these stars are really big compared to their planes. So there's a lot of wiggle room there.

I mean, if the plane of that rotation is totally orthogonal, so it's like if we're seeing the entire motion of the planet around the star and it never goes in front of it, then, yeah, we can't use the transit method at all. But as long as it passes in front of it at some level, then we can use it. Right. But, I mean, we're sort of talking very casually about these techniques, but they're really kind of incredible achievements and technology, right? And math and just kind of an imagination to,

come up with these things. I think they're pretty easy honestly. One of those guys know. I mean, it's just like 10 minutes of coding, right? I mean, you're absolutely right. It's sort of like measuring the effect that the Earth has on our Sun. Like our sun is, you know, thousands if not millions of times bigger than the Earth. So like, you know, we know that the Earth

is affected by the mass of the Sun, but, you know, to think about the tiny little effect that our planet has on the Sun, it must be like minuscule, right? It must be like super little tiny wiggles. No, you're right. It's a triumph of instrumentation and of data analysis and of theory. You know, all those things have to come together.

You have to have a telescope that's capable of seeing this. You have to be able to pull that information out of the noisy data you get. And then you have to have enough understanding to say, here's what it should look like if this is happening and then see that in your data, right? So it's a complex dance of various strains of intellectual effort that came together to make this possible. It's a huge accomplishment. And it's really opened up our eyes to the way the universe. works. And this wobble method is pretty good, but it's hard to see. The transit method has been much more successful in terms of just sheer numbers of planets. And now we have thousands of planets

that we found outside the solar system. But that one's also hard to see. I mean, you're looking at a star is just like a point in the sky. And you're looking for like a little tiny dip as a little tiny ball of frog passes in front of that little star, right? Yeah, absolutely. And it's more complicated because what if stars have multiple planets, right? And, like, how do you know which planet is which? And their orbits can be very different. And so you could be looking at a very difficult, I understand pattern of a star.

And, like, is that just variation in the star? Or is it a dust cloud passing in front of it? There's a lot of different things to disentangle. It's a complicated thing to do. It's not just like, hey, I noticed this star is twinkling. Therefore, there's a planet around it, right? It's a hard thing to do. It's some really impressive science and some,

data science for sure. Wow. Because that's kind of what it is. It's like you're finding a planet inside of the twinkle of a star. Yeah, exactly. That's pretty cool. You're interpreting the twinkles of stars as saying, come visit us. We have a place for you to live. So that's kind of the main method, right? Like that's the most predominant method. But also there's now new technology that lets you see these other planets. Like you can somehow blot out the light from that other star and you can actually see the little dots kind of floating around them. Yeah, you can actually direct image some planets. Now, it's limited to planets that are pretty close

because they have to be close enough for them to have an apparent enough distance from the star that you can tell them apart. Maybe it's super-duper far away, then they're basically on top of each other. So the closer they are, the more likely you are to direct image them. Also, it's much easier to image a planet once you know it's there. So you can use, like, the transit method to say, oh, this star definitely has a planet orbiting it and we can even tell what the period is

so we can tell where it is, then you can zoom in and you can say, Hubble, look at that and look at it really carefully for a while, and then we'll pick it out. It's sort of like, where's Waldo. Once somebody tells you where he is, like, boom, it's easy to spot and you can study him in great detail.

Finding them initially can be pretty tricky, right? Right. I think that should be the name under the first planet we go to Planet Waldo. No, they have to have some sort of sterile name. You know, it should be a Waldo 39X or something like that. Alpha Waldo. 39. Waldo Jorge 39X.

There you go. On that note, let's take a quick break. I'm Dr. Scott Barry Kaufman, host of the psychology podcast. Here's a clip from an upcoming conversation about exploring human potential. I was going to schools to try to teach kids these skills, and I get eye rolling from teachers. or I get students who would be like, it's easier to punch someone in the face. 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 as a result of it if it's going to be beneficial to you. Because it's easy to say like, go blank yourself, right? It's easy. It's easy to just drink the extra beer. It's easy to ignore, to suppress,

seeing a colleague who's bothering you and just like walk the other way. Avoidance is easier. Ignoring is easier. Denial is easier. drinking is easier, yelling, screaming is easy. Complex problem solving, meditating, you know, takes effort. Listen to the psychology podcast on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

Have you ever wished for a change but weren't sure how to make it? Maybe you felt stuck in a job, a place, or even a relationship. I'm Emily Tish Sussman, and on she pivots, I dive into the inspiring pivots of women who have taken big leaps and their lives and careers. I'm Gretchen Whitmer, Jody Sweeten, Monica Patton, Elaine Welteroff. I'm Jessica Voss. And that's when I was like, I got to go. I don't know how, but that kicked off the pivot of how to make the transition. Learn how to get comfortable pivoting because your life is going to be full of them. Every episode gets real about the why behind these changes and gives you the inspiration and maybe the push to make your next pivot. Listen to these women and more on She Pivots, now on the IHeart Radio app, Apple Podcasts, or wherever you get your, Podcasts. Smokey the Bears. Then you know why Smokey tells you when he sees you passing through. Remember, please be careful.

It's the least that you can do. Because it's what you desire. Don't play with matches. Don't play with fire. After 80 years of learning his wildfire prevention tips, Smokey Bear lives within us all. Learn more at smoky bear.com. And remember,

Only you can prevent wildfires. you by the USDA Forest Service, your state forester, and the ad council. Okay, so now we can tell that there are other planets in other stars. So what do we know about all these other planets out there? Right. Well, the amazing thing is that we know that there's a lot of them, like not just one or two, but an enormous number of planets out there. And we know now, and we didn't know 30 years ago,

that there are more planets in the galaxy than stars. What? Wait, what? Yeah. There are more planets than stars in our galaxy. So like on average, every star you see out there in the night sky has more than one planet around them, on average. Yeah, absolutely.

On average, more than one. And so whereas before all we could see were the stars, right? We could see eight planets and billions of stars. Now we can see billions of stars and we know that there are billions and billions of planets around them as well. So that just blows your mind. The universe is littered with planets. That's right. It's lousy with planes.

Yeah, you know what I mean? They're not... Planets are not rare. They're like... They are not at all rare. They're everywhere. You know, everybody's got a planet. Like, if the sun used to feel like special,

hey, man, look at all these cool planets I got. Turns out it's pretty ordinary thing to have. You know, everybody's got planets. It's still... It's last year's cool thing. That's an important thing to know, because if you're a fan of finding alien life, one of the big questions is how many planets are out there.

You know, another question is, are they suitable for life? But just even knowing that the number of planets out there is in the billions rather than in the dozens is a huge factor in that calculation. Wow. Suddenly the probability that there are aliens is much higher because there are, right? Yeah, I don't know. I mean, I would say it's much less non-zero. It's much more non-zero.

Oh, I see. Less unlikely. It's less unlikely, yes. There's one way that could have killed it that is no longer killing the probability, right? there's lots of other things that could mean that life is not everywhere in the universe right even if the universe is filled with earth-like planets

with water and sun and everything that doesn't mean they're filled with life also that's another question but this one aspect could have been a bottleneck and isn't in fact I heard that almost every star out there on average has about one to three earth-sized planet around them

meaning like there's a planet sort of about the same size as ours there's three of them possibly around every star you see in the night sky. Yeah, you know, the weird thing is that the most common planet around stars are between the size of Earth and Neptune, right?

So, bigger than Earth and smaller than Neptune. The odd thing is there are none of those in our solar system. Our solar system is weird in that way. So, I mean, in some ways, it's not, we're not unusual. Like, we've got planets, everybody's got planets. But our set of planets is a little

strange, right? So far what we're learning is that most other solar systems don't look like ours. And I think you're right. There are Earth-sized planets distributed through lots of solar systems. But not every star has an Earth-like planet when you factor in that they have to be near enough to the sun to be warm and not too far away to be cold. So in terms of sun-like stars, stars that are similar to our sun, I think one in five of

those have Earth-sized planets that have reasonable amount of solar radiation. so the temperature should be, you know, within human range. Oh, I see. So there's billions and billions of planets out there, but not all of them are in the ideal zone for life. That's right. You're typing in Earths into your Zillow or your other real estate home finder, and you're going to narrow down your search.

You're looking for ones that are approximately Earth-sized and rocky, but as we said earlier, also have to be in the Goldilocks zone, so they're close enough to the sun to get enough warmth and not so close that they get fried. So that's one in five sunlight. stars. I mean, it's not a huge field for you. Going from like billions and billions and billions of planets to still billions and billions of planets that are sort of like Earth. Yeah. I think

technically you go from cajillions to bazillions. Which is, you know, less unlikely. That's right. So the short version of the story is that Earth-like planets are everywhere, right? I mean, you look up with the night sky and one in five sun-like stars has an Earth-like planet around it. Wow. That's incredible, right? 30 years ago, we thought we might be one of the only ones. And now we know that there are possible houses everywhere for us. So we've got a lot of open houses to go to. So, I mean, we're in L.A., and so we can see maybe five stars in the night sky on a good night.

But if you're out there in another part of the country, you might see like, you know, 5,000 stars when you walk out at night. And that means there are 1,000 Earth-like planets that you can see out there, right? That's right. Just like in your presence. You're in the presence of thousands of Earth-like planets. planets. Yeah, and how many of them are looking back at you and wondering, hmm, that looks like a nice place to move, right?

Let's colonize and eat them. That's the flip side of it, right? If there are other Earth-like planets on there with life, what if they're screwing up their atmosphere and they're looking to move in over here? Oh, no. We need a wall. A space wall. Space wall.

That should be the next order of business after Space Force. And the aliens should pay for it. I wonder if they'll leave this in. Yeah, so all those planets are out there. And so for those of you feeling like, oh, my gosh, we're, you know, it's an embarrassment of riches. We have so many places we can move. Let's just like burn this place to the ground and move somewhere else. These distances we're talking about are still pretty vast, right?

Some of the nearest stars we found with planets around them are still like 12 light years away, which is really, really far away. Wait, the nearest Earth-like planet is 12. light years away. Yeah, 12 light years away. You might think, oh, that's no big deal. Let's just get in a rocket, right? How long would that take is?

Well, there's a lot of constraints there. If you assume sort of current technology, then, you know, you can't get going really very fast at all. And there's limitations on how much you can accelerate. Like the human body cannot handle acceleration beyond a few Gs. So the short version is that it takes tens of thousands of years to get there. tens of thousands of years. So, like, human history is not even tens of thousands of years old.

Again, depending on how much credit you give the Greeks and the Egyptians and stuff. But, yeah, they'll be longer than written history. Yeah, for sure. If we're going to get there, you need to either progenically freeze everybody or have some sort of colony ship where there are generations and generations born on the ship and live and die on the ship and never set foot on a planet. That's sort of crazy to imagine. And survive this incredible crazy journey, right?

and not get hit by an asteroid or run out of food. Yeah, exactly. So basically, while there are a ton of hotels out there we could move to, we're just never going to get there, probably. I mean, one thing we're focusing on in our current strategy for planet searching is to find more close-by planets. And that's for two reasons. One is, of course, we want to find another place we could potentially colonize,

but also that makes it easier to study. Because the second thing that people have been doing recently It's not just finding the planets, but studying them, like, trying to understand which ones might have air, which ones might have water on them. We can do crazy things now, like analyzing what's in the atmosphere of a planet around another star. Wait, so before we couldn't even see them, and now we can tell what it would be like to be there. Like, you can see the air in those little planets. Yeah, it's incredible. You know, what used to be totally impossible and fantastical is now just like normal technology.

and in 20 years we'll be able to do something even more impressive. The way we do that is we look at the light that passes through the atmosphere of the planet as it blocks that star. So the light passes through the atmosphere and some of it gets absorbed and some of it doesn't get absorbed. And how it gets absorbed depends on what's in that atmosphere. So if there's a lot of water in that atmosphere, then certain frequencies of light will get absorbed more or less. And the same thing with hydrogen and methane and all this stuff. So that we can tell what's in the atmosphere that planet based on the spectrum of light, that's getting absorbed or not absorbed as it passes through that atmosphere.

And this is very difficult, right? It's hard enough even just to tell that there's a planet there, but then you analyze it sort of in another dimension, in the spectral dimension, to understand what's around that planet. And that's how, for example, we've discovered water around planets, around other stars. It's amazing. So the new telescope that was launched just a month ago, it's called Tess, and it's got an incredible capability for looking at this

this transit method for finding other planets around stars, and it's going to discover tens of thousands of planets. And the really cool thing is that it's focused on nearby planets. And so it's going to find lots and lots in our neighborhood that we could study and understand their weather and, you know, and maybe even, here's my fantasy, see signs in the atmosphere of something that looks like biology. Oh, wow.

Yeah, that would be amazing. I mean, say you see like methane in the atmosphere of that planet, and methane is something that's produced by life, and maybe the methane cycles with the seasons or you see other weird stuff in the atmosphere right are we going to talk about alien farts again daniel is it where it's going every podcast in the end is about alien farts uh methane methane yeah because that's kind of what um biology produces right about the other end that's right and we could see that that's right in these little flips yeah exactly all right so we hope that we've inspired you to understand that there are lots and lots of earth

like planets out there. And there are lots of places that we could potentially visit. But remember that those places are still pretty far away. And so before you start packing your bags and set in fire to the Earth, remember that we have a long way to go before we could ever reach those planets. And so this one that we're living on is still a really valuable, precious jewel. That's right. It's not a hotel. It's your house. That's right. So once you're done with this podcast and you download the next one, go outside and do something nice for the Earth. Yeah.

Like, tell your friends about this podcast. That's right. Exactly. All right. Thanks, everyone. Have a good one. 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 Danielandhorpe. 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. Denials is easier. complex problem solving, takes effort.

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