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

0:07
Speaker 1: In the last thirty years, our vision of what the
0:10
Speaker 1: universe looks like and how likely it is that we
0:12
Speaker 1: can find another home has completely changed. So before we
0:16
Speaker 1: could see other planets in our solar system. We saw
0:20
Speaker 1: our Jupiter Mars, but we didn't know if there were
0:24
Speaker 1: other planets out there. That's right, and we only have
0:28
Speaker 1: this one example, so that's all we could draw. And
0:30
Speaker 1: of course we wondered how unusual are we could be
0:33
Speaker 1: possibly be the only solar system with planets around it,
0:35
Speaker 1: It seems ridiculous, But as far as we know, we're
0:37
Speaker 1: the only system with life in it as well. So
0:40
Speaker 1: these are deeply intertwined questions like are we unusual in
0:44
Speaker 1: the universe or are we typical? And until a few
0:46
Speaker 1: decades ago, we didn't know at all. We had no
0:49
Speaker 1: information because we couldn't see outside our solar system. But
0:52
Speaker 1: now that's all changed. We are not alone. We may
0:56
Speaker 1: be alone, but there are other planets out there. Hi,
1:14
Speaker 1: I'm and I'm Daniel, and welcome to our podcast. Daniel
1:17
Speaker 1: and Jorne explained the universe in which we take the
1:20
Speaker 1: universe and we searched through if for tiny little bits
1:23
Speaker 1: of fascinating knowledge that we can download into your brain.
1:26
Speaker 1: The question today is are there other Earths? Are there
1:34
Speaker 1: other planets out there where we could potentially move if
1:37
Speaker 1: we screw this one up? Do we have somewhere else
1:39
Speaker 1: to go? Right? Do we have a backup plan if
1:42
Speaker 1: we're when we screwed up, when it's definitely a win,
1:47
Speaker 1: when we ruin this place, when we trash this hotel
1:50
Speaker 1: room that we we've been birthed in, do we have
1:52
Speaker 1: another place to go? Is that feasible at all? Yeah?
1:55
Speaker 1: Or is the Earth like this super mare jem that's
1:58
Speaker 1: just perfect for life and it's nowhere else in the universe?
2:02
Speaker 1: Can you find a planet like the Earth? Right? And
2:04
Speaker 1: I don't know which message is sort of more valuable,
2:07
Speaker 1: Like do you want to tell people, hey, look, the
2:09
Speaker 1: universe is filled with opportunity to encourage exploration of space
2:13
Speaker 1: and the scientific discovery that comes along with it. Or
2:16
Speaker 1: do you want to encourage people to treat Earth as unique,
2:19
Speaker 1: like this is the only place we could ever live,
2:21
Speaker 1: so take care of it. People don't be so silly,
2:24
Speaker 1: you know, Like it's sort of like a parenting choice,
2:27
Speaker 1: you know, how honest are you with with your kids
2:29
Speaker 1: about whether you could actually buy them more food? You know, yeah, like,
2:33
Speaker 1: do you want to tell people they live in a
2:34
Speaker 1: hotel or in their house because people probably take care
2:37
Speaker 1: of their house a little bit better, right, But if
2:39
Speaker 1: you know it's a hotel, that's right. Yeah, then you
2:41
Speaker 1: know you're you're throwing chairs and uh and having big
2:45
Speaker 1: parties and you know, like your typical rock style. I mean,
2:48
Speaker 1: I know that's how you travel horre, isn't it. You
2:50
Speaker 1: need a trail of trash hotel rooms behind you, right? Yeah? Yeah, No, totally,
2:54
Speaker 1: cartoonists lead a wildlife. Everybody knows that you're just drawing
3:01
Speaker 1: from experience. Um, anyway, apologize for my plan there. Yeah,
3:05
Speaker 1: but we're wondering how much do people know about other
3:08
Speaker 1: planets out there? Like, um, what the probability was that
3:12
Speaker 1: there are other planets that we could potentially go and
3:14
Speaker 1: live on. Yeah, people walking around under the assumption that
3:17
Speaker 1: we have a backup plan there's no big deal and
3:20
Speaker 1: we could just bail on this one hit to the
3:21
Speaker 1: next one. Or people operating as if this is the
3:24
Speaker 1: only jewel in the universe and we got to take
3:26
Speaker 1: care of it. So Daniel went out there as usual
3:29
Speaker 1: and ask people in the street, do you think there
3:31
Speaker 1: are other earths out there. Here's what they had to say. Uh, well,
3:37
Speaker 1: it might be, but there might be so far that
3:40
Speaker 1: we cannot reach them. Oh, certainly, I mean the universe
3:44
Speaker 1: is big enough that's it's ground to happen at least once. Definitely,
3:48
Speaker 1: I think I think the universe is too big to
3:52
Speaker 1: just have us as the special like higher beings. People
3:56
Speaker 1: seem to have a lot of confidence that there are
3:58
Speaker 1: other places for us to live. Most everybody said there
4:01
Speaker 1: are definitely other planets out there. Yeah, I guess everyone's
4:04
Speaker 1: comfortable with the idea that the universe is humongous and
4:06
Speaker 1: so therefore we can't possibly be the only nice blue
4:11
Speaker 1: planet out there. I know, and I like the idea
4:14
Speaker 1: of the universe is humongous because it is, and I
4:17
Speaker 1: get that it suggests that we shouldn't be unusual, But
4:20
Speaker 1: it certainly doesn't provide a rock solid argument. I mean,
4:23
Speaker 1: that's not an argument that this is a big place
4:25
Speaker 1: and therefore there must be more of us. Until you've
4:28
Speaker 1: seen another earth, until you've discovered life somewhere else, you
4:31
Speaker 1: don't know if we're the only place that has these features, right,
4:34
Speaker 1: it could certainly be that we are the only place
4:37
Speaker 1: where life could exist. I mean, if there was only
4:39
Speaker 1: one place for life to exist in the universe, that
4:42
Speaker 1: would be the place people ask that question. Right, So
4:45
Speaker 1: I feel like people make that argument, but there's a
4:47
Speaker 1: missing piece there. Right. You have to know that the
4:50
Speaker 1: other earths can happen. You have to understand the mechanism
4:53
Speaker 1: for their formation or something to argue that there really
4:55
Speaker 1: are other other earths out there. Yeah. I wonder if
4:58
Speaker 1: people are are just conditioned from staching so many sci
5:00
Speaker 1: fi movies, you know that show other planets, and you know, coincidentally,
5:05
Speaker 1: all those other planets look just like Earth because were
5:09
Speaker 1: filmed unearthed mostly around Los Angeles. Hey, look this planet
5:15
Speaker 1: looks like Malibu. Yeah, well, that's so weird. It's terrible traffic.
5:20
Speaker 1: We're so steeped in science fiction and they're being aliens
5:23
Speaker 1: and other planets. I wonder if it's just kind of
5:25
Speaker 1: a like a given that there would be other planets,
5:28
Speaker 1: or maybe science has done a good job of like
5:30
Speaker 1: teaching people how vast the universe is and how many
5:32
Speaker 1: stars threw are up there. Yeah. I think NASA has
5:35
Speaker 1: usually done a great job about announcing their discoveries and
5:38
Speaker 1: what they've learned to the general public, so other science
5:40
Speaker 1: agencies can definitely take a page out of their playbook,
5:44
Speaker 1: but also because it touches on something which people are
5:46
Speaker 1: curious about. Me you just need to look up at
5:48
Speaker 1: the sky at night and you can see the grand
5:50
Speaker 1: mystery that is the universe. Other fields of science, you know,
5:53
Speaker 1: chemistry or even particle physics are not quite as successible
5:56
Speaker 1: because their mysteries don't jump in your face every single
5:59
Speaker 1: evening when you look up at the stars. So I
6:02
Speaker 1: think it connects to people's imagination a little bit more
6:05
Speaker 1: um and and also to their you know, this this
6:07
Speaker 1: idea that humanity is on a trajectory that we're you know,
6:11
Speaker 1: we haven't flatlined or plateaued or peaked, that we're just
6:14
Speaker 1: you know, we've explored Earth and we've developed technology, and
6:17
Speaker 1: that's clearly the next step is to go out into
6:19
Speaker 1: the stars and to spread this disease slash um blessing
6:24
Speaker 1: that is humanity um into other places in the universe.
6:27
Speaker 1: It's like our a manifest destiny or something. I think
6:30
Speaker 1: there's a lot of that feeling, and maybe that comes
6:31
Speaker 1: from science fiction, or maybe just comes from the human
6:34
Speaker 1: need to build and develop and explore space, and so
6:37
Speaker 1: I think people want there to be these other earths
6:39
Speaker 1: out there. So I think part of this feeling that
6:42
Speaker 1: the universe might be filled with Earth's is a hope, right,
6:45
Speaker 1: it's a hopeful thought. Nobody wants to say. No. I
6:48
Speaker 1: think the universe is a desert and we are the
6:50
Speaker 1: the only oasis, and we're probably gonna die here today. Like,
6:54
Speaker 1: you know, it's a I was mostly young people I
6:57
Speaker 1: was talking to, so maybe they're just a more hopeful crowd.
7:03
Speaker 1: So maybe we should talk first about what we want
7:05
Speaker 1: in another earth. Like we're shopping for new homes and
7:08
Speaker 1: you usually decide how many bedrooms you want and all
7:10
Speaker 1: that stuff. So let's make our shopping list for like
7:13
Speaker 1: what another Earth should look like. What do you look
7:15
Speaker 1: for in a planet for he uh, you know, WiFi
7:18
Speaker 1: is pretty up there, power outlets, not freezing temperatures, breathable air,
7:26
Speaker 1: breathable air, Yeah, that might be too much to ask for. Um.
7:30
Speaker 1: I think number one should be like a rocky surface, right.
7:33
Speaker 1: We don't want to live on a gas giant right
7:35
Speaker 1: where you just like it's a dense clouds all the
7:38
Speaker 1: way down to like a surface of molten rock or
7:41
Speaker 1: something in the core. We need something that's enough rock
7:43
Speaker 1: on it that we can stand. Right, So, rocky planets
7:46
Speaker 1: rather than gas gashes planets, I think is item number
7:48
Speaker 1: one on my list. Um. Yeah, because you know, even
7:51
Speaker 1: the planets we have in our solar system that we
7:53
Speaker 1: know about, there's only one of them that we could
7:56
Speaker 1: actually hang out in. Right, Yeah, I think we could
7:58
Speaker 1: probably make Mars work. Right, Mars is on the edge
8:01
Speaker 1: of that that zone. It's a little too cold, but
8:04
Speaker 1: you know, if we were able to tearra form it
8:05
Speaker 1: and add an atmosphere and a magnetic field, then it
8:08
Speaker 1: would probably warm up pretty nicely. Thanks. We don't know
8:10
Speaker 1: how to do yet things if we don't know how
8:12
Speaker 1: to do yet, but I'm hopeful, right, I'm hopeful the
8:15
Speaker 1: humanity can do these kinds of things. Right. This is
8:17
Speaker 1: the accessing the positive side of my personality. So, but yeah,
8:21
Speaker 1: most of the planets in our solar system not well
8:23
Speaker 1: suited for life at all. Yeah. So you need a
8:26
Speaker 1: rocky surface, You need to be the right temperature. Right.
8:28
Speaker 1: You can't be too close to the Sun so you
8:30
Speaker 1: get blasted by fire every day, and you can't be
8:32
Speaker 1: too far away so you're freezing all the time. Right,
8:35
Speaker 1: And where that zone is depends on how hot your
8:37
Speaker 1: star is. If your star is much much hotter and
8:40
Speaker 1: then our star, then you have to be further away, obviously.
8:42
Speaker 1: And if the star is cooler, then you can be
8:44
Speaker 1: much closer to the Sun, which would be really amazing.
8:47
Speaker 1: Like imagine being on a planet that's closer to their star.
8:50
Speaker 1: So then even though it's not any hotter, the star
8:53
Speaker 1: takes up a larger portion of the sky. You could
8:56
Speaker 1: have like a huge red sun in the sky. If
8:59
Speaker 1: your planet is going around a red dwarf. Oh you mean,
9:02
Speaker 1: you could feel the same way as here, but our
9:04
Speaker 1: sky would be like basically a big red circle. Yeah.
9:08
Speaker 1: Or if you have a much much hotter sun, you
9:10
Speaker 1: could be further from it, so even though it feels
9:13
Speaker 1: like the same amount of heat and radiation, the sun
9:15
Speaker 1: in that world would be just like a dot in
9:17
Speaker 1: the sky would look the same size as you know,
9:19
Speaker 1: almost any other star, but it would be just as warm.
9:23
Speaker 1: It could be like we could see that's just another star,
9:25
Speaker 1: but it could be the one thing that's warminess. Yeah, exactly.
9:29
Speaker 1: So the the experience of being around another star with
9:32
Speaker 1: the same amount of heat captured by the surface could
9:36
Speaker 1: be a very different experience from the point of view
9:38
Speaker 1: what the sky looks like anyway. So we want a
9:40
Speaker 1: planet with a rocky surface, we want about the right temperature, right,
9:43
Speaker 1: we'd like some atmosphere. Certainly, we need a magnetic field.
9:48
Speaker 1: Why do we need a magnetic field, because we've got
9:49
Speaker 1: to protect ourselves from solar radiation all sorts of other stuff.
9:53
Speaker 1: To remember, magnetic fields bend particles, and so if you
9:56
Speaker 1: have some dangerous high speed particle coming from space, you
9:59
Speaker 1: need then magnetic field to deflect it. Like Earth has
10:02
Speaker 1: a really nice magnetic field which gives us like a
10:04
Speaker 1: shield against cosmic radiation. So you absolutely need a magnetic field.
10:08
Speaker 1: That's kind of a necessary condition for a planet to
10:11
Speaker 1: be happitable. Yeah, space is filled with harmful radiation. You
10:15
Speaker 1: can't go out in the space without serious radiation shielding.
10:17
Speaker 1: And our planet house radiation shielding is the atmosphere combined
10:20
Speaker 1: with the magnetic field. Absolutely, so planet without a magnetic
10:23
Speaker 1: field would require us to like constantly wear radiation shielding
10:27
Speaker 1: or build a radiation shield, or you can actually construct
10:31
Speaker 1: a radiation shield using a strong magnet you put out
10:33
Speaker 1: in space. That would be pretty cool, But you definitely
10:36
Speaker 1: need some sort of sort of shielding, and that actually
10:38
Speaker 1: rules out a huge category of places to live because
10:42
Speaker 1: the center of the galaxy pumps out an enormous amount
10:45
Speaker 1: of radiation because of all the crazy activity that's happening
10:48
Speaker 1: in their black holes and and dense stars and all
10:51
Speaker 1: sorts of crazy stuff we don't actually really understand because
10:53
Speaker 1: the center of the galaxy is a hard place to study,
10:56
Speaker 1: but it's pumping out so much deadly radiation that even
10:59
Speaker 1: the planets around stars that are anywhere near there could
11:02
Speaker 1: not support life because the magnetic fields are not strong enough.
11:05
Speaker 1: So you have to be far enough away from the
11:07
Speaker 1: center of the galaxy also to be safe from that
11:09
Speaker 1: kind of radiation. Oh, your whole Solar system could be
11:12
Speaker 1: in a bad neighborhood. Yeah, the entire swaths of stars
11:16
Speaker 1: that just because they're close to the galactic center could
11:19
Speaker 1: never really host life, you know, as we know it.
11:21
Speaker 1: Maybe some sort of super radiation hard life could develop there,
11:24
Speaker 1: and people with thicker skin, that's right, people with thicker
11:28
Speaker 1: skins and bad since the year um, well, this is
11:32
Speaker 1: a perfect point to take a break. So that's what
11:46
Speaker 1: we mean by another Earth, Like, is there another planet
11:49
Speaker 1: with the same conditions that we have here, and so
11:53
Speaker 1: that's that's kind of the question. And so but I
11:55
Speaker 1: guess the first question is are there other planets at
11:57
Speaker 1: all in other stars? Right? Like, we sort of take
12:00
Speaker 1: that for granted that other stars have other little balls
12:03
Speaker 1: of rock floating around them, But up until a few
12:05
Speaker 1: years ago, we had no idea, we had no confirmation.
12:08
Speaker 1: That was just the hypothesis. That's right, And it's a
12:11
Speaker 1: really cool story. In fact, it has really cool first
12:13
Speaker 1: chapter to it, which is that only a few decades
12:16
Speaker 1: ago they figured out how to look for these these
12:19
Speaker 1: planets around other stars. And one one of the primary
12:22
Speaker 1: ways that one of the first ways they did it
12:24
Speaker 1: is by seeing stars wiggle. And so what happens is
12:28
Speaker 1: that you have a planet going around a star, and
12:30
Speaker 1: you think, of, okay, there's a planet's going around a star.
12:33
Speaker 1: And that's happening because the star is much bigger than
12:35
Speaker 1: the planet, so the planet orbits the star. Right, that's
12:37
Speaker 1: mostly true. But there's a little caveat there, which is
12:41
Speaker 1: the gravity works in both ways. Right, the star is
12:43
Speaker 1: pulling the planet and the planet is pulling the star.
12:46
Speaker 1: So it actually happens is not just that the planet
12:50
Speaker 1: is moving around the star, but the two of them
12:52
Speaker 1: are moving around their center of mass and moving around
12:55
Speaker 1: this point that's that's between the two of them, so
12:58
Speaker 1: both of them move. So you can tell if a
13:00
Speaker 1: star has planets around it based on whether or not
13:03
Speaker 1: it's wiggling back and forth because it's getting tugged on
13:06
Speaker 1: by that planet. It's kind of like if you had
13:08
Speaker 1: if you were swinging a rock and a string, even
13:10
Speaker 1: if it was a little rock, you would still feel
13:13
Speaker 1: that the pool of the rock right like you would
13:15
Speaker 1: still sway back and forth as you were swinging in yeah, exactly.
13:19
Speaker 1: So they figured out how to do this, and they
13:20
Speaker 1: started looking and they found planets. But the amazing thing
13:23
Speaker 1: is they went back through historical data, like data from
13:26
Speaker 1: telescopes from a hundred years ago, and they found this
13:30
Speaker 1: evidence in ancient data, like somebody in nineteen seventeen had
13:34
Speaker 1: taken careful data about the location of a star and
13:37
Speaker 1: they had seen wiggles, and at the time people have
13:40
Speaker 1: been like, what's this, I don't know, I don't know.
13:42
Speaker 1: It must be something wrong or it's noise in your data.
13:44
Speaker 1: Then they went back later and realized this is beautiful
13:47
Speaker 1: data that showed evidence of an exoplanet, but it just
13:51
Speaker 1: hadn't been recognized at the time. So we had this
13:54
Speaker 1: information a hundred years ago, it was just ignored. It
13:57
Speaker 1: was just like not understood. Well, let's let's take a
14:00
Speaker 1: step back. Why is it so hard to see planets
14:02
Speaker 1: in other stars? You know, like in our solar system,
14:05
Speaker 1: you can see Mars and the night sky, you can
14:08
Speaker 1: see Saturn, you can see the rings around Saturn, so
14:11
Speaker 1: you can see other planets that are in our solar system.
14:14
Speaker 1: But that's actually much more difficult to see that in
14:18
Speaker 1: other solar systems. Right, that's right, And think about what
14:20
Speaker 1: you're seeing when you look at that planet. Right, planets
14:23
Speaker 1: look bright in the sky. Why is that, Well, they're
14:25
Speaker 1: not little stars. They're not giving off light. They're mostly
14:28
Speaker 1: reflecting light the same way the moon is. Right, why
14:31
Speaker 1: can't you see the moon in the moon is just
14:32
Speaker 1: a dark rock. Why can you see it? You can
14:35
Speaker 1: see the part of it that's illuminated by the sun.
14:38
Speaker 1: You can see the light reflecting off it from the Sun.
14:40
Speaker 1: So moonlight is really just reflected sunlight, right, And all
14:44
Speaker 1: the light from Mars, for example, is the light that
14:46
Speaker 1: started at the Sun bounced off of Mars and then
14:49
Speaker 1: came to Earth. So the reason we can see those
14:51
Speaker 1: planets is because they reflect the light of our star, right,
14:54
Speaker 1: and because they're not so close to the star. Right right,
14:58
Speaker 1: you think about another solar system far away, then the
15:01
Speaker 1: planets are really close to that star compared to their
15:04
Speaker 1: their distance from us. So Mars is really far to
15:08
Speaker 1: the star compared to its distance from us. So you
15:10
Speaker 1: can see it away from the Sun. If you look
15:12
Speaker 1: at the nearest solar system, the planets are really close
15:15
Speaker 1: to the star. And so even if they reflect light,
15:18
Speaker 1: it's just a tiny little bit and it's basically included
15:21
Speaker 1: in the blob that comes from the star. We can't
15:23
Speaker 1: really tell them apart. Right, So like if you were
15:26
Speaker 1: to point a telescope at another star in the night sky,
15:29
Speaker 1: you would just get blinded by the light from the
15:31
Speaker 1: that star that you were looking at. Right, that's right,
15:34
Speaker 1: because in your telescope, the planets look really close to
15:37
Speaker 1: that star because the distance between them and the star
15:40
Speaker 1: is tiny compared to the distance between them and us.
15:42
Speaker 1: It's like if you look at another if you look
15:44
Speaker 1: at another city through binoculars, right, you can't really see
15:47
Speaker 1: any details. You can just maybe see that it's there. Yeah,
15:50
Speaker 1: Like it was described to me as um like, imagine
15:52
Speaker 1: that your friend was standing next to the world's brightest
15:56
Speaker 1: lighthouse holding a little lighter, you know, or a little
15:59
Speaker 1: man uch little flame. It would be like you trying
16:03
Speaker 1: to discern that flame that your friend was holding from
16:06
Speaker 1: like three thousand miles away. Basically all you would see
16:09
Speaker 1: is the light from the lighthouse. You wouldn't be able
16:12
Speaker 1: to see the little flicker next to it. Yeah, and
16:14
Speaker 1: I think I think actually that's overly optimistic, because planets
16:17
Speaker 1: don't give off their own light like a lighter does. Right.
16:20
Speaker 1: It's like if somebody's holding up a rock next to
16:22
Speaker 1: a lighthouse and you're trying to see that rock at
16:25
Speaker 1: night from three thousand miles away based on how much
16:27
Speaker 1: light it reflects from the lighthouse. Yeah, it's really it's
16:30
Speaker 1: almost impossible, right, It sounds impossible, which is why up
16:34
Speaker 1: until like thirty years ago, when we didn't have the technology,
16:37
Speaker 1: there was no way we could have seen any other
16:40
Speaker 1: planets besides the one in our Solar system, well directly right,
16:43
Speaker 1: in terms of like using telescopes to see that light
16:46
Speaker 1: and say like here is a picture of that planet.
16:48
Speaker 1: That was impossible until fairly recently, but strategies to see
16:52
Speaker 1: them indirectly have been possible for a while. We just
16:55
Speaker 1: didn't realize it. Oh. I see, So you're saying that
16:58
Speaker 1: historical data that you heard about, basically we had like
17:01
Speaker 1: the data to know that there were other planets and
17:03
Speaker 1: other stars, we just didn't know to look for it.
17:06
Speaker 1: That's right, And to me that's tantalizing because you know,
17:10
Speaker 1: whoever that was in nineteen seventeen that got that data,
17:12
Speaker 1: they basically missed out on a Nobel prize right discovery
17:15
Speaker 1: of Excel planet. And this data was sitting there in
17:18
Speaker 1: a in a library or whatever for decades. So of
17:21
Speaker 1: course then the question is what other data is sitting
17:24
Speaker 1: in the library right now, which is somebody knew how
17:26
Speaker 1: to analyze could reveal something amazing about the universe that
17:30
Speaker 1: could win you a Nobel prize. Right, it's out there
17:32
Speaker 1: right now, everybody stop listening to this podcast and go
17:35
Speaker 1: to the science library and figure it out. Or maybe
17:38
Speaker 1: in your computer, Danue right like, there'd be something in
17:41
Speaker 1: your data that you're not seeing. Who knows, there's certainly
17:44
Speaker 1: could be, There's certainly could be anyway. To me, that's
17:46
Speaker 1: a fascinating wrinkle when you look back and you see
17:48
Speaker 1: data from history that people didn't understand at the time
17:51
Speaker 1: what it meant. Okay, So that's the idea that it's
17:57
Speaker 1: really hard to look at other planets and other stars directly.
18:01
Speaker 1: So the first confirmation that there were other stars out
18:03
Speaker 1: there came indirectly from looking at how stars wobble, right,
18:07
Speaker 1: and also like how the the light from stars changes. Right. Yeah,
18:11
Speaker 1: So the first method was the wobble method, and it
18:14
Speaker 1: uses gravity to see how the planets are are wiggling
18:17
Speaker 1: the stars. And the second method, it's called the transit method.
18:20
Speaker 1: And this is the idea is still you're looking at
18:22
Speaker 1: the star because it's all you can really see directly,
18:25
Speaker 1: and you watch the stars light and as the planet
18:28
Speaker 1: goes in front of the star, the light from the
18:30
Speaker 1: star should get a little dimmer. It's like a little eclipse.
18:33
Speaker 1: Right now, you're not going to cover the whole star.
18:35
Speaker 1: The star is not gonna go totally dark. It just
18:37
Speaker 1: dips by a little bit depending on the size of
18:39
Speaker 1: the planet. But if that happens regularly, right, you watch
18:42
Speaker 1: the same star for weeks and weeks, months and years,
18:45
Speaker 1: and you notice a pattern, then you can deduce that
18:48
Speaker 1: there's a planet there, and you can figure out what's
18:51
Speaker 1: its period, how often does it go around the Sun,
18:54
Speaker 1: and you can figure out how big is it, what
18:56
Speaker 1: fraction of the light of the star is it blocking.
18:59
Speaker 1: But you know that it's sort of assumes that the
19:01
Speaker 1: orbit of the planet goes around in a circle, that
19:04
Speaker 1: it's just kind of like perfectly in the same level
19:07
Speaker 1: as we are. You know, like exactly, you could have
19:10
Speaker 1: a planet going around another star, but it could be
19:13
Speaker 1: going like you know, in a circle, um kind of
19:15
Speaker 1: perpendicular to us, so you would never see it create
19:18
Speaker 1: an eclipse. But if it's just how happens to be
19:20
Speaker 1: kind of on the same level as we we would
19:22
Speaker 1: you would see it kind of passed in front of
19:24
Speaker 1: the star between us and that star. That's right, it
19:27
Speaker 1: has to pass between us and that star. You're totally right.
19:30
Speaker 1: But remember that these stars are really big compared to
19:32
Speaker 1: their planets, so there's a lot of wiggle room there.
19:35
Speaker 1: I mean, if the plane of that rotation is totally orthogonal,
19:39
Speaker 1: So if it's like if we're seeing the entire motion
19:42
Speaker 1: of the planet around the star and it never goes
19:44
Speaker 1: in front of it, then yeah, we can't use the
19:45
Speaker 1: transit method at all, but as long as it passes
19:48
Speaker 1: in front of it at some level, then we can
19:50
Speaker 1: use it. Right. But I mean, we were start of
19:52
Speaker 1: talking very casually about these techniques, but they're really kind
19:55
Speaker 1: of incredible achievements in technology, right, and math and and
20:01
Speaker 1: just kind of imagination to come up. And I think
20:04
Speaker 1: I think they're pretty easy, honestly, one of those guys. No,
20:08
Speaker 1: I mean, it's just like I mean minutes of coding, right,
20:10
Speaker 1: I mean, you're you're sort of like measuring the effect
20:13
Speaker 1: that the Earth has on our Sun. Like our sun
20:15
Speaker 1: is you know, thousands of not millions of times bigger
20:18
Speaker 1: than the Earth. So like, you know, we know that
20:20
Speaker 1: the Earth is affected by the mass of the Sun.
20:23
Speaker 1: But you know, to think about the tiny little effect
20:25
Speaker 1: that our planet has on the Sun, it must be
20:28
Speaker 1: like mini skill, right, must be like super little tiny wiggles. Now,
20:32
Speaker 1: you're right. It's a triumph of instrumentation and of data
20:35
Speaker 1: analysis and of theory. You know, all those things have
20:38
Speaker 1: to come together. You have to have a telescope that's
20:41
Speaker 1: capable of seeing this. You have to be able to
20:43
Speaker 1: pull that information out of the noisy data you get,
20:46
Speaker 1: and then you have to have enough understanding to say,
20:48
Speaker 1: here's what it should look like if this is happening,
20:51
Speaker 1: and then see that in your data. Right. So it's
20:53
Speaker 1: a complex dance of various strains of intellectual effort that
20:57
Speaker 1: came together to make this possible. It's a huge acomplishment
21:00
Speaker 1: and it's really opened up our eyes to the way
21:02
Speaker 1: the universe works. And it's wobble method is pretty good,
21:06
Speaker 1: but it's it's it's hard to see. Um. The transit
21:09
Speaker 1: method has been much more successful in terms of just
21:12
Speaker 1: like sheer numbers of planets and now we have thousands
21:15
Speaker 1: of planets that we found outside the Solar System. But
21:17
Speaker 1: that one's also hard to see. I mean, you're looking
21:19
Speaker 1: at a star is just like a point in the sky,
21:22
Speaker 1: and you're looking for like a little tiny dip as
21:25
Speaker 1: a little tiny ball of frog passes in front of
21:28
Speaker 1: that little star. Right, Yeah, absolutely, And it's more complicated
21:31
Speaker 1: because what if stars have multiple planets, right, and like
21:35
Speaker 1: how do you know which planet is which? And their
21:38
Speaker 1: orbits can be very different, and so you could be
21:40
Speaker 1: looking at a very difficult to understand pattern of a
21:42
Speaker 1: star and like is that's just variation in the star
21:46
Speaker 1: or is this a dust cloud passing in front of it.
21:48
Speaker 1: There's a lot of different things to disentangle. It's a
21:50
Speaker 1: complicated thing to do. It's not just like, hey, I
21:53
Speaker 1: noticed this star is twinkling, therefore there's a planet around it, right,
21:57
Speaker 1: It's it's a hard thing to do. It's some really
22:00
Speaker 1: impressive science and some data science for sure, because that's
22:03
Speaker 1: kind of what it is. It's like you're you're finding
22:05
Speaker 1: a planet inside of the twinkle of a star. Yeah, exactly,
22:09
Speaker 1: that's pretty cool. You're interpreting the twinkles of stars as saying,
22:12
Speaker 1: come visit us. We have a place for you to live.
22:17
Speaker 1: So that's kind of the main method, right, Like that's
22:19
Speaker 1: the most predominant method. But also there's no new technology
22:23
Speaker 1: that lets you see these other planets. Like you can
22:25
Speaker 1: somehow blot out the light from that other star and
22:29
Speaker 1: you can actually see the little thoughts kind of floating
22:31
Speaker 1: around them. Yeah, you can actually direct image some planets. Now,
22:35
Speaker 1: it's limited the planets that are pretty close, because they
22:37
Speaker 1: have to be close enough for them to have an
22:39
Speaker 1: apparent enough distance from the star that you can tell
22:42
Speaker 1: them apart me, if it's super duper far away, then
22:44
Speaker 1: it's they're basically on top of each other, so the
22:47
Speaker 1: closer they are, the more likely you are to direct
22:49
Speaker 1: you into them. Also, it's much easier to image a
22:51
Speaker 1: planet once you know it's there, so you can use
22:54
Speaker 1: like the transit method to say, oh, this star definitely
22:57
Speaker 1: has a planet orbiting it, and we can even tell
22:59
Speaker 1: what the period is, so we can tell where it is.
23:02
Speaker 1: Then you can zoom in and you can say, hubble,
23:05
Speaker 1: look at that and look at it really carefully for
23:06
Speaker 1: a while, and then we'll pick it out. It's sort
23:08
Speaker 1: of like where's Waldo when somebody tells you where he is,
23:11
Speaker 1: like boom. It's easy to spot and you can study
23:13
Speaker 1: them in great detail. Finding them initially can be pretty tricky,
23:16
Speaker 1: right right. I think that should be the name under
23:18
Speaker 1: the first planet we go to, Planet Waldo. You know
23:22
Speaker 1: that have to have some sort of um sterile name.
23:24
Speaker 1: You know, it should be Waldo thirty nine X or
23:27
Speaker 1: something like that. Off, well, Waldo, Waldo Orge thirty nine X.
23:33
Speaker 1: There you go. On that note, let's take a quick break. Okay,
23:49
Speaker 1: so now we can tell that there are other planets
23:52
Speaker 1: in other stars. So what do we know about all
23:54
Speaker 1: these other planets out there? Right? Well, the amazing thing
23:57
Speaker 1: is that we know that there's a lot of them,
23:58
Speaker 1: like not just one or two, but an enormous number
24:02
Speaker 1: of planets out there. And we know now we didn't
24:04
Speaker 1: know thirty years ago that there are more planets in
24:06
Speaker 1: the galaxy than stars. Wait what Yeah, there are more
24:10
Speaker 1: planets than stars in our galaxy. So like, on average,
24:13
Speaker 1: every star you see out during the night sky has
24:15
Speaker 1: more than one planet around them on average. Yeah, absolutely,
24:19
Speaker 1: on average more than one. And so whereas before all
24:23
Speaker 1: we could see where the stars, right, we could see
24:25
Speaker 1: eight planets and billions of stars, now we can see
24:29
Speaker 1: billions of stars and we know that there are billions
24:31
Speaker 1: and billions of planets around them as well. So that
24:35
Speaker 1: just blows your mind. The universe is literate with planets.
24:38
Speaker 1: That's right. It's lousy with you know what I mean.
24:41
Speaker 1: They're not planets are not rare. They're they're like, they
24:45
Speaker 1: are not at all rare. They're everywhere. You know, everybody's
24:48
Speaker 1: got a planet. Like if the Sun used to feel
24:50
Speaker 1: like special, Hey man, look at all these cool planets
24:52
Speaker 1: I got. It turns out it's pretty ordinary thing to have.
24:55
Speaker 1: You know, everybody's got planets. It's so it's last year's
24:58
Speaker 1: cool thing. That's an important thing to know because if
25:00
Speaker 1: you you know, if you're a fan of finding alien life,
25:03
Speaker 1: one of the big questions is how many planets are
25:05
Speaker 1: out there? You know, another question is are they suitable
25:07
Speaker 1: for life? But just even knowing that the number of
25:10
Speaker 1: planets out there is in the billions rather than in
25:12
Speaker 1: the dozens is a huge factor in that calculation. Suddenly
25:15
Speaker 1: the probabability that there are aliens is much higher because
25:19
Speaker 1: there are right before. I don't know, I mean, I
25:23
Speaker 1: would say it's much less non zero, it's much more,
25:26
Speaker 1: much more non zero, less unlikely, it's less unlikely. Yes,
25:31
Speaker 1: there's one way that could have killed it. That is
25:33
Speaker 1: no longer killing the probability. Right, there's lots of other
25:37
Speaker 1: things that could mean that life is not everywhere in
25:40
Speaker 1: the universe. Right, Even if the universe is filled with
25:42
Speaker 1: earthlike planets with water and sun and everything, that doesn't
25:45
Speaker 1: mean they're filled with life. Also, that's another question. But
25:48
Speaker 1: this one aspect could have been a bottleneck and isn't.
25:51
Speaker 1: In fact, they heard that almost every star out there,
25:53
Speaker 1: on average has about one to three earth size planet
25:58
Speaker 1: around them, meaning there's a planet sort of about the
26:02
Speaker 1: same size as ours. There's three of them possibly around
26:05
Speaker 1: every star you see in the night sky. Yeah, you know.
26:08
Speaker 1: The weird thing is that the most common planet around
26:11
Speaker 1: stars are between the size of Earth and Neptune, right,
26:15
Speaker 1: so bigger than Earth and smaller than Neptune. The odd
26:18
Speaker 1: thing is there are none of those in our solar system.
26:21
Speaker 1: Our solar system is weird in that way. So, I mean,
26:25
Speaker 1: in some ways, it's not We're not unusual, like we
26:27
Speaker 1: got planets. Everybody's got planets, but our set of planets
26:30
Speaker 1: is a little strange, right. So far, what we're learning
26:34
Speaker 1: is that most other solar systems don't look like ours.
26:37
Speaker 1: And I think you're right. There are Earth sized planets
26:40
Speaker 1: um distributed through lots of solar systems, but not every
26:43
Speaker 1: star has an earthlike planet. And when you factor in that,
26:47
Speaker 1: they have to be near enough to the Sun to
26:48
Speaker 1: be warm and not too far away to be cold.
26:51
Speaker 1: So in terms of Sun like stars, you know, stars
26:54
Speaker 1: that are similar to our Sun, I think one in
26:57
Speaker 1: five of those have Earth sized and it's that have
27:01
Speaker 1: reasonable amount of solar radiation, so that temperature should be
27:04
Speaker 1: you know, within human range. Oh, I see, So there's
27:07
Speaker 1: billions and billions of planets out there, but not all
27:10
Speaker 1: of them are in the ideal zone for life. That's right.
27:14
Speaker 1: You're typing in Earth's into your into Zillo or your
27:17
Speaker 1: on the real estate home finder, and you know you're
27:20
Speaker 1: gonna narrow down your search. You're looking for ones that
27:22
Speaker 1: are approximately Earth sized and rocky, but as we said earlier,
27:25
Speaker 1: also have to be in the Goldilocks zone, so they're
27:27
Speaker 1: close enough to the Sun to get enough formed, then
27:29
Speaker 1: not so close that they get fried. So that's one
27:32
Speaker 1: in five sun like stars. I mean, it's not a
27:34
Speaker 1: huge field. For you're going from like billions and billions
27:37
Speaker 1: and billions of planets to still billions and billions of
27:39
Speaker 1: billions of planets that are sort of like Earth. Yeah,
27:43
Speaker 1: I think technically you go from jillions to bazillions, which is,
27:48
Speaker 1: you know, less unlikely. That's right. So the short version
27:52
Speaker 1: of the story is that Earth like planets are everywhere, right,
27:56
Speaker 1: I mean, you look with the night sky and one
27:58
Speaker 1: in five sun like stars as an earthlike planet around it.
28:01
Speaker 1: That's incredible. Right, Thirty years ago we thought we might
28:05
Speaker 1: be one of the only ones, and now we know
28:07
Speaker 1: that there are possible houses everywhere for us. Crazy we
28:10
Speaker 1: got a lot of open houses to go to. So,
28:12
Speaker 1: I mean we're in l a and so we can
28:14
Speaker 1: see maybe five stars in the night sky on a
28:16
Speaker 1: good night. But if you're out there in another part
28:19
Speaker 1: of the country, you might see, like, you know, five
28:21
Speaker 1: thousand stars when you walk out at night. And that
28:23
Speaker 1: means there are a thousand earthlike planets that you can
28:27
Speaker 1: see out there. Right, that's rights our presence. You're in
28:31
Speaker 1: the presence of five thousands of earth like planets. Yeah,
28:34
Speaker 1: and how many of them are looking back at you
28:35
Speaker 1: and wondering that looks like a nice place to move, right,
28:39
Speaker 1: Let's colonize and eat them. That's the that's the flip
28:42
Speaker 1: side of it, right, If there are other earthlike planets
28:44
Speaker 1: on there with life, what if they're screwing up their
28:46
Speaker 1: atmosphere and they're looking to move in over here? We
28:49
Speaker 1: need a wall, a space wall, baseball. That should be
28:55
Speaker 1: the next order of business after space plans. The aliens
28:59
Speaker 1: should pay for it. Oh, I wonder if they'll leave
29:04
Speaker 1: this in Yeah, So all those planets are out there,
29:10
Speaker 1: and so for those of you feeling like, oh my gosh,
29:12
Speaker 1: we have we're you know, it's an embarrassment of riches.
29:14
Speaker 1: We have so many places we can move, let's just
29:16
Speaker 1: like burn this place to the ground and move somewhere else.
29:20
Speaker 1: These distances we're talking about are still pretty vast, right,
29:23
Speaker 1: Some of the nearest stars we found with planets around
29:26
Speaker 1: them are still like twelve light years away, which is
29:29
Speaker 1: really really far away. Wait, the nearest earthlike planet is
29:32
Speaker 1: twelve light years away. Yeah, twelve light years away. You
29:36
Speaker 1: might think, oh, that's no big deal, let's just get
29:37
Speaker 1: in the rocket, right, How long would that take? Well,
29:40
Speaker 1: there's a lot of constraints there. If you assume sort
29:43
Speaker 1: of current technology, Um, then you know you can't get
29:47
Speaker 1: going really very fast at all, and it's limitations on
29:51
Speaker 1: how much you can accelerate, Like the human body cannot
29:53
Speaker 1: handle acceleration beyond a feugs. So the short version is
29:58
Speaker 1: that it takes tens of thousands of years to get there.
30:01
Speaker 1: Tens of thousands of years, so like human history is
30:04
Speaker 1: not even tens of thousands of years old. Again, depending
30:07
Speaker 1: on how much credit you give the Greeks and the
30:09
Speaker 1: Egyptians and stuff, but yeah, it's they'll be longer than
30:12
Speaker 1: written history. So if we're going to get there, you
30:15
Speaker 1: need to either progenically freeze everybody, or have some sort
30:18
Speaker 1: of colony ship where there are generations and generations born
30:21
Speaker 1: on the ship and live and die on the ship
30:23
Speaker 1: and never set foot on a planet. That's sort of
30:26
Speaker 1: crazy to imagine and survive this incredible, crazy journey, right
30:30
Speaker 1: and not get hit by an asteroid or run out
30:32
Speaker 1: of food or yeah, exactly. So basically, while there are
30:35
Speaker 1: a ton of hotels out there we could move to there,
30:38
Speaker 1: we're just never going to get there probably. I mean,
30:42
Speaker 1: one thing we're focusing on in our current strategy for
30:45
Speaker 1: for for planets searching is to find more close by planets,
30:48
Speaker 1: and that's for two reasons. One is, of course, we
30:50
Speaker 1: want to find another place we could potentially colonize, but
30:53
Speaker 1: also that makes it easier to study, because the second
30:55
Speaker 1: thing that people have been doing recently is not just
30:57
Speaker 1: finding the planets but studying them, like trying to understand
31:00
Speaker 1: which ones might have um air, which ones might have
31:03
Speaker 1: water on them. We can do crazy things now like
31:06
Speaker 1: analyzing what's in the atmosphere of a planet around another star. Wait,
31:11
Speaker 1: so before we couldn't even see them, and now we
31:14
Speaker 1: can tell what it would be like to be there,
31:17
Speaker 1: Like you can see the air in those little planets. Yeah,
31:20
Speaker 1: it's incredible. You know what used to be totally impossible
31:23
Speaker 1: and fantastical is now just like normal technology. And in
31:26
Speaker 1: twenty years we'll be able to do something even more impressive.
31:28
Speaker 1: The way we do that is we look at the
31:30
Speaker 1: light that passes through the atmosphere the planet as it
31:33
Speaker 1: blocks that star. So the light passes through the atmosphere
31:37
Speaker 1: and some of it gets absorbed and some of it
31:39
Speaker 1: doesn't get absorbed, and how it gets absorbed depends on
31:41
Speaker 1: what's in that atmosphere. So if there's a lot of
31:43
Speaker 1: water in that atmosphere, then certain frequencies of light will
31:46
Speaker 1: get absorbed more or less. In the same thing with
31:48
Speaker 1: hydrogen and methane and all this stuff, So that we
31:51
Speaker 1: can tell what's in the atmosphere in that planet based
31:53
Speaker 1: on the spectrum of light that's that's getting absorbed or
31:57
Speaker 1: not absorbed as it passes through that atmosphere. And this
32:00
Speaker 1: is very difficult, right, It's hard enough even just to
32:03
Speaker 1: tell that there's a planet there, but then you analyze
32:05
Speaker 1: it sort of in another dimension, in the spectral dimension,
32:08
Speaker 1: don't understand what's around that planet. And that's how, for example,
32:11
Speaker 1: we've discovered water around planets around other stars. It's amazing.
32:18
Speaker 1: So the new telescope that was launched just a month ago,
32:21
Speaker 1: it's called Tests, and it's an incredible capability for looking
32:25
Speaker 1: at this this transit method for finding other planets around stars,
32:28
Speaker 1: and it's going to discover tens of thousands of planets.
32:31
Speaker 1: And the really cool thing is that it's focused on
32:34
Speaker 1: nearby planets, and so it's going to find lots and
32:37
Speaker 1: lots in our neighborhood that we could study and understand
32:39
Speaker 1: their weather and you know, and maybe even here's my fantasy,
32:44
Speaker 1: see signs in the atmosphere something that looks like biology. Yeah,
32:49
Speaker 1: that would be amazing. I mean, say, you see like
32:51
Speaker 1: methane in the atmosphere that planet, and methane is something
32:53
Speaker 1: that's produced by life, and maybe the methane cycles with
32:56
Speaker 1: the seasons or you see other weird stuff in the atmosphere. Right,
33:00
Speaker 1: we're gonna talk about farts again, Daniel. Is that every
33:04
Speaker 1: podcasting the end is about alien farts methane? Yeah, because
33:10
Speaker 1: that's kind of what a biology produces right out the
33:14
Speaker 1: other end, that's right, and we could see that that's
33:16
Speaker 1: right in these little blips. Yeah, exactly, Alright, so we
33:21
Speaker 1: hope that we've inspired you to understand that there are
33:23
Speaker 1: lots and lots of earthlike planets out there, and there
33:26
Speaker 1: are lots of places that we could potentially visit um.
33:29
Speaker 1: But remember that those places are still pretty far away.
33:32
Speaker 1: And so before you start packing your bags and setting
33:35
Speaker 1: fire to the earth, remember that we have a long
33:37
Speaker 1: way to go before we could ever reach those planets.
33:39
Speaker 1: And so this one that we're living on is still
33:41
Speaker 1: a really valuable, precious jewel. That's right. It's not a hotel,
33:45
Speaker 1: it's your house, that's right. So once you're done with
33:49
Speaker 1: this podcast and you're doneload the next one, go outside
33:51
Speaker 1: and do something nice for the earth. Yeah, like tell
33:55
Speaker 1: your friends about this podcast. That's exactly all right. Thanks everyone,
34:01
Speaker 1: have a good one. If you still have a question
34:11
Speaker 1: after listening to all these explanations, please drop us a line.
34:14
Speaker 1: We'd love to hear from you. You can find us
34:16
Speaker 1: at Facebook, Twitter, and Instagram at Daniel and Jorge that's
34:20
Speaker 1: one word, or email us at Feedback at Daniel and
34:24
Speaker 1: Jorge dot com.