Latest / Daniel and Kelly’s Extraordinary Universe / What if the Earth Stopped Spinning

Transcript

What if the Earth Stopped Spinning · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, orr, Hey, do you ever think about how fast
0:11
Speaker 1: you're spinning? Oh? Man, the way this year is going,
0:14
Speaker 1: I feel like by head spinning, that's for sure. Well,
0:17
Speaker 1: there's that, but there's also how the Earth is spinning
0:20
Speaker 1: around its axes, how we're all spinning around the Sun,
0:23
Speaker 1: and how our entire solar system is spinning around the
0:26
Speaker 1: center of the galaxy. Are you gonna spin as a
0:30
Speaker 1: tail about the physics of spin today, Daniel, I just
0:33
Speaker 1: think it's cool how everything in the universe seems to
0:36
Speaker 1: be spinning all the time. See, I knew you put
0:39
Speaker 1: a positive spin on it. Hi. I am or handmade
0:58
Speaker 1: cartoonists and the creator of PhD mix. Hi, I'm Daniel.
1:01
Speaker 1: I'm a particle physicist and I can spin up or
1:04
Speaker 1: I can spin down. Does that officially make you a
1:07
Speaker 1: spin doctor? You are a doctor and you sometimes do
1:12
Speaker 1: research quantum spin, so technically you do belong in a
1:16
Speaker 1: nineties band with a one hit wonder. Yeah. I don't
1:19
Speaker 1: know what's more believable, quantum spin or political spin. Sometimes
1:23
Speaker 1: it all seems made up. It's all um not not true,
1:26
Speaker 1: kind of true and not true at the same time.
1:29
Speaker 1: But welcome to our podcast. Daniel and Jorge explained the
1:31
Speaker 1: Universe a production of Our Heart Radio in which we
1:34
Speaker 1: examine all the amazing things about the universe. We spin
1:38
Speaker 1: them up, we spin them down, we turn them around
1:40
Speaker 1: in your head until they make sense to you. We
1:43
Speaker 1: think that wondering about the universe belongs to everybody, that
1:46
Speaker 1: your curiosity is the thing that drives science as much
1:50
Speaker 1: as the curiosity of scientists themselves. And so we take
1:54
Speaker 1: a journey all around the universe and ask big and
1:56
Speaker 1: deep and important questions about how things work and try
1:59
Speaker 1: to give you answers. That makes sense, Yeah, because the
2:02
Speaker 1: universe is a pretty big place, and there's a lot
2:05
Speaker 1: to explore and a lot to ask questions about, from
2:08
Speaker 1: the far reaches of the cosmos to our everyday lives
2:11
Speaker 1: and even what's happening right here on Earth. That's right.
2:14
Speaker 1: The physics that's literally under our feet has a big
2:17
Speaker 1: impact on how we live our lives and what's going on. Yeah,
2:21
Speaker 1: And we like to talk about not just kind of
2:23
Speaker 1: the what we know about the universe out there, what
2:25
Speaker 1: scientists know, but also what they're asking about the universe,
2:30
Speaker 1: including what if questions. That's right. We like to let
2:34
Speaker 1: Jorge wander into the control panel of the universe and
2:37
Speaker 1: start flipping switches. What happens if you turn off quantum mechanics?
2:41
Speaker 1: What happens if you delete dark energy or dark matter?
2:44
Speaker 1: And this is not just some cartoonists idol speculation about
2:47
Speaker 1: the universe. This is an important way to do physics,
2:50
Speaker 1: to think about could the universe have been different? What
2:53
Speaker 1: would it look like if we turned something off or
2:56
Speaker 1: something didn't happen. I feel like these are questions, Daniel,
2:59
Speaker 1: that supervillains have at their meetings in brainstorming sessions. It's like,
3:04
Speaker 1: what if we turn off dark energy here on Earth?
3:08
Speaker 1: How can we use that? How can we spend that
3:10
Speaker 1: to our advantage? Can we demand a five billion dollar
3:13
Speaker 1: ransom for not turning off dark energy? Right? Build a
3:17
Speaker 1: laser on the Moon? I think actually that was the
3:19
Speaker 1: plot of one of those movies. Yeah, it seems it
3:22
Speaker 1: seemed kind of quiet now because I think in those
3:24
Speaker 1: Austin Power movies he would ask for one billion dollars,
3:27
Speaker 1: which nowadays, you know, considering things, seems pretty small. Well,
3:32
Speaker 1: if it helps people, maybe they can imagine you doing
3:35
Speaker 1: this podcast from your underground volcano layer. That's right with
3:40
Speaker 1: my pinky next to my mouth. Stroking my cat or
3:44
Speaker 1: meani version of me. But if it makes you nervous
3:47
Speaker 1: to imagine Jorge at the control panels of the universe,
3:50
Speaker 1: then instead, remember these are just thought experiments. These are
3:53
Speaker 1: ways for us to imagine how the universe might be
3:55
Speaker 1: different and to wonder if it could be different. Yeah,
3:59
Speaker 1: because that's a big part of how SIGNS is actually done, right, Daniel,
4:02
Speaker 1: I mean when you're when you get together with your
4:05
Speaker 1: other physicist colleagues, do you sort of think about, like
4:08
Speaker 1: what would happen if this happened, or what would happen
4:10
Speaker 1: if this disappeared, or what would happen if this stuff
4:14
Speaker 1: that working? Yeah? Absolutely, we are often reverse engineering the universe.
4:19
Speaker 1: We're imagining what are the possible different scenarios that are
4:23
Speaker 1: consistent with what we see, Because what we'd love to
4:26
Speaker 1: do is make some set of observation, some things we
4:29
Speaker 1: see about the universe that tell us uniquely how the
4:32
Speaker 1: universe has to be. But an important part of that
4:35
Speaker 1: is sort of creatively thinking like is there another explanation?
4:39
Speaker 1: Is there something else that could have happened that explains
4:42
Speaker 1: what we see? And so you have to go through
4:44
Speaker 1: these thought experiments. You have to imagine what if there
4:47
Speaker 1: was no dark energy? Or what if the Sun turns
4:50
Speaker 1: into a black hole? Or how do we know that
4:52
Speaker 1: there isn't another planet out there? You have to imagine
4:55
Speaker 1: all those other crazy scenarios before you can dismiss them,
4:58
Speaker 1: and sometimes they lead to cra easy discoveries because they
5:01
Speaker 1: turn out to actually be true. Yeah, because you know,
5:04
Speaker 1: thought experiments are a lot cheaper than actual experiments. Right,
5:07
Speaker 1: they don't cause billions of dollars, just a few billion neurons.
5:11
Speaker 1: I still ask for billions of dollars from my thought experiments.
5:14
Speaker 1: But yeah, they don't go to building experiments. They just
5:16
Speaker 1: go to you know, funding my elaborate volcano layer inside
5:19
Speaker 1: of your head inside, that's right. Yeah, So today we'll
5:24
Speaker 1: be asking you a question that Um, it's pretty impactful.
5:27
Speaker 1: I mean it sort of affects everyone's lives on a
5:30
Speaker 1: daily basis, and in fact, it's sort of kind of
5:33
Speaker 1: defined to day for us. That's right. It's all about
5:36
Speaker 1: what's going on under our feet, and it's about how
5:39
Speaker 1: our world is moving and where it's going. Yeah, so
5:42
Speaker 1: we'd like to stay grounded in this podcast, so to
5:44
Speaker 1: be on the podcast, we'll be asking the question what
5:52
Speaker 1: if the Earth stop spinning now, Jorge, in your super
5:56
Speaker 1: villain brainstorming meeting, are you imagining sudden stopping the earth
6:01
Speaker 1: or sort of like gradually stopping it and turning it
6:03
Speaker 1: the other direction? I guess if I was a super villain,
6:06
Speaker 1: I would be aiming for maximum damage, Like what the
6:10
Speaker 1: worst case scenario? So whichever one of those give me
6:13
Speaker 1: the most ransom money? I guess as a super villain,
6:17
Speaker 1: that's that's optimal, right, I don't know. There's a delicate
6:19
Speaker 1: balance there. If you're blackmailing or extorting something, you want
6:22
Speaker 1: them to stay alive so they can continue to fund
6:24
Speaker 1: you in the future. Right. You don't want to obliterate
6:27
Speaker 1: your crime victims. You want to slurp some money out
6:30
Speaker 1: of them, but keep them functioning. I see, if you're
6:32
Speaker 1: a super villain, you would go for the subscription model,
6:35
Speaker 1: not the one time payment. You're more like the free
6:39
Speaker 1: to play type of game. That's right, because those victims
6:43
Speaker 1: never remember to cancel their orders and you just keep
6:45
Speaker 1: building their credit cards month after month. Man, that would
6:49
Speaker 1: make a pretty good plot for a movie. Uh anyway,
6:55
Speaker 1: So um, yeah, that's a pretty interesting question, Daniel, How
6:57
Speaker 1: did you come up with this question. This is a
6:59
Speaker 1: question and that a bunch of readers wrote in and
7:01
Speaker 1: asked us. It's something people think about, and it tells
7:04
Speaker 1: you that it's not just physicists out there that wonder
7:07
Speaker 1: about things in the universe. It's also everybody. And maybe
7:10
Speaker 1: some of our listeners are potential future supervillains. I hope not,
7:17
Speaker 1: because then we'd be enabling them in some way, Daniel.
7:20
Speaker 1: But also, you know a lot of our listeners are physicists,
7:23
Speaker 1: and in fact, isn't isn't everybody a physicist in a
7:25
Speaker 1: certain way? Yes, exactly. If you're the kind of person
7:28
Speaker 1: who does this kind of thinking, who thinks maybe the
7:30
Speaker 1: universe could be like this, what would happen if that happened,
7:33
Speaker 1: then you're doing physics and that makes you a certified physicist. Boom,
7:38
Speaker 1: Daniel will give you a PhD. Just right into PhDs
7:42
Speaker 1: for free at Daniel and Horg. Yes, welcome to your
7:45
Speaker 1: PhD in Internet physics. Yeah. So it so it seems
7:49
Speaker 1: to be a question that a lot of people are
7:51
Speaker 1: having out there. I guess where does that come from? Daniel?
7:54
Speaker 1: Does it feel like, you know, it's something so normal
7:58
Speaker 1: and some something that we're so used to that, you know,
8:00
Speaker 1: it's very curious to think about what would happen if
8:03
Speaker 1: it stopped. Yeah, I think that there's a lot of
8:06
Speaker 1: times in the history of science when we realized that
8:09
Speaker 1: something we thought was like bedrock truth, was fundamental to
8:12
Speaker 1: our universe, turned out to not be true. And so
8:15
Speaker 1: that gives you this instinct to question everything, to wonder,
8:19
Speaker 1: why is this happening? What would it be like if
8:21
Speaker 1: it stopped happening? And so I think that's where the
8:23
Speaker 1: instinct comes from, just to look around and ask questions
8:26
Speaker 1: about the basic nature of our reality. And I wonder
8:29
Speaker 1: how many people who are wondering this question think something
8:31
Speaker 1: good would happen as opposed to something not good. I
8:36
Speaker 1: don't think anybody imagines, Oh, I have a great idea,
8:39
Speaker 1: let's stop the earth from spitting, because it really annoys me.
8:43
Speaker 1: How we had daytime the vampire lobby, or maybe it's
8:50
Speaker 1: you know, cartoonists late for their deadline and wondering like,
8:53
Speaker 1: could I eke out a few more hours of late
8:55
Speaker 1: night effectiveness if I somehow stopped the earth. M That
9:00
Speaker 1: seems like a lot more work than actually doing the
9:02
Speaker 1: doing the thing. But that's the lesson in procrastination, isn't it?
9:07
Speaker 1: And you remember Superman did this once. Something happened he
9:10
Speaker 1: didn't like, and so he turned the Earth the other direction, somehow,
9:14
Speaker 1: reversing the flow of time to undoate the death of
9:17
Speaker 1: Lois Lane. What did your physics sense tell you when
9:22
Speaker 1: you watched that movie? Was it? Did it freak out?
9:24
Speaker 1: I think I was like a seven year old physicist
9:26
Speaker 1: when I first watched that movie, and I thought, huh,
9:29
Speaker 1: how could earth itself control the flow of time? That's ridiculous.
9:33
Speaker 1: M Do you think, um, well, gosh, I feel like
9:36
Speaker 1: we get into the whole episode about the Superman movies.
9:40
Speaker 1: Do you think he or Superman in general. Uh, do
9:43
Speaker 1: you think he spun the earth the other way? Or
9:46
Speaker 1: do you think he went back in time himself? Well,
9:49
Speaker 1: that's the other explanation for that scene. I see you're
9:51
Speaker 1: imagining he's going faster than the speed of light, and
9:54
Speaker 1: so somehow he goes back in time. Um, yeah, yeah, perhaps,
9:58
Speaker 1: But doesn't he isn't he pushing on the earth? Isn't
10:00
Speaker 1: actually spinning at the other direction. I have to go
10:02
Speaker 1: back and review that scene. But even he he just
10:05
Speaker 1: flies over it. Oh, he just plays out somehow that's
10:08
Speaker 1: that that makes the Earth spin the other way. For me,
10:10
Speaker 1: it was just he was just going back in time.
10:13
Speaker 1: I see, Yeah, well you know my feelings about time
10:16
Speaker 1: travel and fiction. It's all gibberish. I thought you're gonna
10:21
Speaker 1: say Superman, but um, I guess you were more specific.
10:25
Speaker 1: But anyways, we're wondering how many people out there have
10:27
Speaker 1: thought about this question or even have a possible answer
10:31
Speaker 1: to it. So, as usual, Daniel went out there into
10:34
Speaker 1: the Internet and ask folks to send in their answers.
10:38
Speaker 1: That's right, and thank you to the listeners who volunteered
10:41
Speaker 1: to answer questions without any research, just from the top
10:44
Speaker 1: of their head. If you'd like to offer answers to
10:47
Speaker 1: tricky topics without any preparation, please write to us two
10:50
Speaker 1: questions at Daniel and Jorge dot com. So think about
10:54
Speaker 1: it for a second. What do you think would happen
10:56
Speaker 1: if the Earth stops spinning? Here's what people had to say.
11:00
Speaker 1: I'm not sure what controls your spin. Perhaps has something
11:04
Speaker 1: related to the distance to the Sun and as well
11:09
Speaker 1: then the Moon, and maybe the gravity of other objects.
11:12
Speaker 1: Also could be that the flow of the inner cord,
11:18
Speaker 1: all the molten metal and the inside Maybe play a
11:21
Speaker 1: role I have. I don't know if they have no clue,
11:25
Speaker 1: and I guess it it may be decreasing in speed.
11:29
Speaker 1: I don't see why would it be increasing. But also
11:33
Speaker 1: that would mean that in any way that days are
11:35
Speaker 1: becoming either shorter or longer somehow. So far, I haven't
11:40
Speaker 1: seen the dis is an issue, but I guess it
11:42
Speaker 1: should be in a very small scale. What controls the
11:46
Speaker 1: Earth spin is its slowing down. Um the Earth and
11:52
Speaker 1: the Earth was born, and this is the way the
11:56
Speaker 1: Earth was born, spinning. UM. I don't exactly what control
12:01
Speaker 1: Probably the core controls the spinning, and UM, I think
12:09
Speaker 1: it's slowing down, but I don't know by how much.
12:15
Speaker 1: On the top of my head, I can't really think
12:17
Speaker 1: of any factors that would cause the Earth to spin
12:21
Speaker 1: around an axis. So I'm guessing that when it was formed,
12:26
Speaker 1: when the Earth was formed, the matter was spinning and
12:29
Speaker 1: it's just sort of kept on going. So I would say, yes,
12:33
Speaker 1: it's probably slowing down. UM. And I know that other
12:36
Speaker 1: planets also spin, but I think they're quite different speeds,
12:41
Speaker 1: so I'm guessing it's not anything to do with their size.
12:45
Speaker 1: So yeah, my guess would be that it's sort of
12:48
Speaker 1: It's just kept on spinning since it was formed, and
12:51
Speaker 1: nothing's stopping it is just friction. But as far as
12:55
Speaker 1: why it rotates at the speed it does about the
12:59
Speaker 1: north and south, I'm not sure why. I'm not sure
13:02
Speaker 1: what caused it. I did here a long time ago
13:04
Speaker 1: that it's slowing down. I'm sure the Earth received all
13:10
Speaker 1: of its spin in its primordial creation, and if it
13:14
Speaker 1: were a rigid body, a piece of rock, then it
13:17
Speaker 1: would keep spinning with the same angular momentum forever. But
13:22
Speaker 1: the Earth is not a rigid body. He has a
13:25
Speaker 1: fluid core, and a fluid core is subject to convection
13:29
Speaker 1: and other movements and forces, and therefore it must be
13:34
Speaker 1: losing some of the spin to friction and heat. And
13:38
Speaker 1: by the second law of thermodynamics, I suppose it must
13:41
Speaker 1: be losing spin better than acquiring spin. Whether this is
13:45
Speaker 1: a big effect or not, I'm not sure. I think
13:48
Speaker 1: the conservation of um angler momentum. It's probably the reason
13:54
Speaker 1: why the Earth is still spinning. Well, it is sloving
13:58
Speaker 1: town um, and it is being slowed down by the
14:01
Speaker 1: title forces from the Moon and also the Sun of
14:06
Speaker 1: course a other planets too, probably, but their effect is negligible.
14:12
Speaker 1: I think we add lip seconds because of that. All right,
14:16
Speaker 1: I feel like this these answers reveal a lot about
14:19
Speaker 1: our audience, Daniel, all of them short of trying to
14:22
Speaker 1: get down to the to the reason why the Earth
14:24
Speaker 1: would stop exactly. You have to wonder what's controlling the
14:28
Speaker 1: Earth spin. You can't just be like I'm just going
14:30
Speaker 1: to turn it off. You can't just like wander into
14:33
Speaker 1: the control room at the universe and flip a switch, right.
14:35
Speaker 1: You gotta follow the rules, right, and nobody said Supervillain
14:39
Speaker 1: or Orge flipping switches where you relieved we were. You're
14:45
Speaker 1: gonna be blamed here. I feel like I get blamed
14:48
Speaker 1: for a lot of things that I'm not actually responsible for.
14:52
Speaker 1: But yeah, a lot of interesting answers here though. A
14:56
Speaker 1: lot of them talk about the origin of the Earth
14:58
Speaker 1: spin and the future of the Earth spin, and so
15:01
Speaker 1: that's that's pretty fascinating stuff, all right. So let's dive
15:04
Speaker 1: into Daniel. Um, I guess maybe maybe a very basic
15:07
Speaker 1: question and just just take a step back, is to
15:10
Speaker 1: talk about why the Earth is spinning in the first place, right,
15:14
Speaker 1: Like we're so used to it turning around and giving
15:17
Speaker 1: us daytime. In my time, but you know, maybe not
15:20
Speaker 1: a lot of people haven't thought about why it is
15:22
Speaker 1: actually doing that. I mean, it's possible that it could
15:25
Speaker 1: not have been right. I guess it's possible. But you know,
15:28
Speaker 1: the amazing thing about spin is when you look out
15:31
Speaker 1: into the universe, essentially everything is spinning. I mean, the
15:34
Speaker 1: Sun is spinning, all the planets are spinning around their
15:37
Speaker 1: acts and then spinning around the Sun, and our solar
15:40
Speaker 1: system is spinning around the galaxy. And so spin is
15:43
Speaker 1: a pretty big part of existing in the universe. It's
15:47
Speaker 1: really kind of fascinating. M I guess it's sort of
15:51
Speaker 1: like motion in general, right, Like in space there's no
15:55
Speaker 1: very little friction, so if you're moving, you're gonna keep moving,
15:59
Speaker 1: or if you're spin you're gonna keep spinning. Yeah, exactly.
16:02
Speaker 1: There's this conservation of spin we call a conservation of
16:05
Speaker 1: angular momentum, which really just means like motion around some access,
16:10
Speaker 1: revolving around some access, spinning, and we have this conservation
16:14
Speaker 1: of angular momentum in our universe. And we talked recently
16:18
Speaker 1: on the podcast about fundamental symmetries. Conservation of angular momentum
16:22
Speaker 1: comes because there's no preferred direction in space and so
16:25
Speaker 1: you can translate that rotational symmetry of the universe into
16:29
Speaker 1: this conservation of angle momentum. But it has a real
16:31
Speaker 1: practical consequence. It means that if something starts spinning, it
16:35
Speaker 1: will continue spinning, right, And so you might ask then,
16:38
Speaker 1: like why is the Solar system spinning? Why is the
16:41
Speaker 1: Earth spinning? It's spinning because the stuff it was made
16:44
Speaker 1: out of was spinning. M And I guess maybe the
16:49
Speaker 1: question is why is the stuff that it started with
16:51
Speaker 1: spinning in the first place? I mean, in the Big Bang?
16:54
Speaker 1: Are you saying the Big Bang thanks for spinning? Yeah,
16:57
Speaker 1: that's a really fun question. It comes down to like
16:59
Speaker 1: how how stuff gets broken up into chunks. Imagine like
17:03
Speaker 1: a big swirling hot plasma, right, there's definitely motion in there.
17:07
Speaker 1: If you then break those things up into pieces, you
17:10
Speaker 1: can ask like, is one of those chunks spinning? Like
17:12
Speaker 1: one of those chunks is destined to be our galaxy
17:15
Speaker 1: or our Solar system or our planet. And if you
17:19
Speaker 1: take all the motion of all those particles is either
17:21
Speaker 1: going to be spinning clockwise or spinning counterclockwise, or perfectly
17:26
Speaker 1: somehow balanced so that there's no spin. And so if
17:30
Speaker 1: all those outcomes it's much more likely for it to
17:33
Speaker 1: be randomly spinning in one direction or the other than
17:36
Speaker 1: for it to be perfectly balanced. Right, But when you're
17:39
Speaker 1: talking about like the spin of a lot of things,
17:42
Speaker 1: you actually sort of mean like the like the overall
17:46
Speaker 1: direction of where each thing is going. You don't mean
17:48
Speaker 1: like each thing is spinning and so overall everything has
17:51
Speaker 1: a spin, right, You mean sort of like, um, you know,
17:55
Speaker 1: if things have a velocity sort of relative to the center,
18:00
Speaker 1: and that's sort of considered spin. Yeah, exactly, It's the
18:03
Speaker 1: motion of the object. So you can, for example, draw
18:05
Speaker 1: a line through it and say, all right, here's the
18:07
Speaker 1: thing I'm going to measure my spin around. And then
18:10
Speaker 1: you could ask how are things moving relative to that?
18:13
Speaker 1: And things that are moving in one direction will give
18:15
Speaker 1: you clockwise spin, and things that are moving the other
18:17
Speaker 1: direction will give you counterclockwise spin. So you've got to
18:20
Speaker 1: add all those up, and then you can get overall
18:22
Speaker 1: in motion. And it's either that it's all balanced so
18:25
Speaker 1: there's like weirdly no spin, or that things tend to
18:29
Speaker 1: be going more in one direction than the other. And
18:31
Speaker 1: if you just take like a random scoop of hot
18:34
Speaker 1: plasma from the early universe. It's got a lot of
18:37
Speaker 1: motion in it, so for that motion to like add
18:39
Speaker 1: up to zero spin would be pretty unusual. It's much
18:42
Speaker 1: more likely for all those things to be moving in
18:45
Speaker 1: direction which adds up to some kind of spin. Right,
18:47
Speaker 1: and then and then I think it's it's it's isn't
18:50
Speaker 1: It kind of like part of the way the physics
18:52
Speaker 1: work that if you just leave that system over time,
18:55
Speaker 1: it's going to eventually turn into a spinning disk. Everything's
19:00
Speaker 1: going to start spinning over around one axis and everything's
19:05
Speaker 1: gonna sort of stop spinning the other ways. Yeah, And
19:08
Speaker 1: that's a fascinating consequence of living in three dimensions because
19:12
Speaker 1: in three dimensions, you can always pick one axis for
19:15
Speaker 1: the spin, and you can always say, here's my axis.
19:18
Speaker 1: I'm gonna measure my spin around this axis, and that's
19:21
Speaker 1: the overall axis around which you have spin, and then
19:24
Speaker 1: gravity can coalesce everything around that axis. Things keep spinning, right,
19:29
Speaker 1: they keep going, but along that axis there's nothing to
19:33
Speaker 1: prevent gravity from flattening things, from things pulling down. So
19:37
Speaker 1: in the three dimensions of our space, you can always
19:40
Speaker 1: pick one axis where all the spin cancels except along
19:44
Speaker 1: that axis. If we lived in four dimensional space, then
19:47
Speaker 1: there would be two axes you could pick where the
19:49
Speaker 1: spin wouldn't cancel. So we live in a three dimensional universe,
19:52
Speaker 1: so there's always like one axis you can find where
19:55
Speaker 1: the spin cancels in two out of the three dimensions,
19:57
Speaker 1: but not around that axis. That's why galaxies and solar
20:01
Speaker 1: systems are discs, because gravity squishes things down along that axis,
20:06
Speaker 1: but not around that axis, right, because it sort of
20:09
Speaker 1: bounces it out um in one direction, but then it
20:13
Speaker 1: it does tend to flatten things in the other direction. Yeah.
20:16
Speaker 1: And this angular momentum is the reason why, for example,
20:19
Speaker 1: the Earth doesn't collapse into the Sun, right, It's the
20:22
Speaker 1: reason why we're still here. If we didn't have angular momentum,
20:25
Speaker 1: then the Earth would just fall into the Sun because
20:27
Speaker 1: of the force of gravity. It's the angular momentum that
20:30
Speaker 1: keeps us in an orbit, that keeps the planets from
20:33
Speaker 1: just collapsing into the Sun, and keeps the galaxy from
20:35
Speaker 1: collapsing into the central black hole. So angular momentum is
20:39
Speaker 1: very much why we're here. Yeah, And and it sort
20:42
Speaker 1: of works at different scales to like you said, like, um,
20:45
Speaker 1: you know, the galaxy is u had looks like a
20:49
Speaker 1: disc because everything spinning on sort of one um flat
20:54
Speaker 1: plane UM. But then the stuff within that plane also
20:57
Speaker 1: sort of callesces and and the same thing happens, and
21:01
Speaker 1: that that starts um spinning in one plane like the
21:05
Speaker 1: Solar system, and then also the stuff in the Solar
21:08
Speaker 1: system starts coming together due to gravity, like the Earth,
21:11
Speaker 1: and then that's also spinning in pretty much almost the
21:14
Speaker 1: same direction, right, yeah, exactly. The Earth spins in the
21:18
Speaker 1: same direction as the planets move around the Sun, and
21:22
Speaker 1: the planets move around the Sun in the same direction
21:24
Speaker 1: as the Sun rotates. Now that's mostly true for everything,
21:29
Speaker 1: and we'll talk about it in a minute. There's sometimes
21:31
Speaker 1: some deviations. Those deviations are really fascinating because they tell you, like,
21:35
Speaker 1: something weird happened here. For example, most of the stars
21:38
Speaker 1: in the galaxy rotate around the center of the galaxy
21:40
Speaker 1: in the same direction, but there are a few things
21:43
Speaker 1: out there they are going the opposite way, that rotate
21:46
Speaker 1: around the center of the galaxy, going the other direction
21:49
Speaker 1: from most of the traffic. I think they're called contrarian stars.
21:54
Speaker 1: No they're not, No, exactly. These are actually globular clusters.
21:58
Speaker 1: These like collections of star and as we'll talk about
22:01
Speaker 1: in a minute. There are some planets in our Solar
22:04
Speaker 1: system that spin in an unusual direction, and so you
22:08
Speaker 1: can ask questions like, if everything else is spinning this way,
22:10
Speaker 1: why is this spinning? The other way to spin is
22:14
Speaker 1: really fundamental to the whole like structure of the universe
22:16
Speaker 1: and the structure of our galaxy, and it reveals lots
22:19
Speaker 1: of interesting clues about how things came to be. All right,
22:22
Speaker 1: let's get into how the other planets in our Solar
22:25
Speaker 1: system spin and what would happen if our planet stop spinning.
22:31
Speaker 1: But first let's take a quick break. All right, Daniel,
22:46
Speaker 1: we are spinning here. We're in a spin class. Uh.
22:50
Speaker 1: And some people might be um listening to this while
22:54
Speaker 1: on a stationary bicycle spinning. But um, but if we're
22:58
Speaker 1: talking about give them some motivation, and you know, push
23:00
Speaker 1: push push, let's just the opposite. Let's encourage him to
23:04
Speaker 1: take it to relax. Why are you? Why are you
23:07
Speaker 1: bicycling so hard? You look great, man, don't worry about it.
23:12
Speaker 1: Think about the spinning doughnut. Alright, So we're talking about
23:16
Speaker 1: spinning things in in space and in our solarcism, And
23:21
Speaker 1: then you were saying that not all planets spin the
23:25
Speaker 1: same way. Yeah, there's a huge variation, not just in
23:28
Speaker 1: the direction of the spin, but in the rate of spin.
23:31
Speaker 1: Like the Earth of course, takes one day to spin.
23:34
Speaker 1: That's how we define a day. And it turns out
23:37
Speaker 1: that Mars also takes about a day to spin. But
23:40
Speaker 1: the bigger planets like Jupiter and Saturn, they spin much faster,
23:43
Speaker 1: like it only takes Jupiter nine hours to spin, and
23:47
Speaker 1: it's a lot bigger, which means it's surface is really
23:50
Speaker 1: going quickly. Do they measure that by like the surface
23:54
Speaker 1: or like do they do we know how fast the
23:56
Speaker 1: core is spinning. We think actually there's differential rotation some
24:00
Speaker 1: of these planets, that the core might be spinning at
24:02
Speaker 1: different speeds than the outer layers. But here we're talking
24:05
Speaker 1: about the outer layers. Were like watching stuff on the
24:07
Speaker 1: surface of the planet move. All right, So, um, there
24:11
Speaker 1: are spinning really quickly. Um, but there are some planets
24:15
Speaker 1: that's been really slowly. Yeah, Mercury and Venus, the ones
24:19
Speaker 1: that are closer to the Sun than us, they spent
24:22
Speaker 1: really slowly, Like Mercury takes fifty eight days to rotate
24:26
Speaker 1: once and Venus takes two hundred and forty three days,
24:31
Speaker 1: which is ridiculous. Yeah, that is weird. And now is
24:34
Speaker 1: there an explanation why some of them spin faster than others.
24:39
Speaker 1: So we don't really know, but we think that some
24:42
Speaker 1: of these things reflect like the history of the objects,
24:46
Speaker 1: like maybe they got hit and that changes their spin.
24:49
Speaker 1: And also it reflects something about the effect of the
24:52
Speaker 1: Sun on these objects, right, because the ones that seemed
24:56
Speaker 1: closer to the Sun seemed to be spinning slower, whereas
24:59
Speaker 1: the ones further out are spinning superfast. Yeah, because the
25:03
Speaker 1: Sun actually plays a big effect on the spin of
25:05
Speaker 1: these planets. It's not just like the original stuff that
25:08
Speaker 1: was spinning and is still spinning. The Sun is massaging
25:11
Speaker 1: these planets. There are gravitational tides on these planets. So
25:15
Speaker 1: the Sun pulls harder on the bits of the planets
25:17
Speaker 1: that are closer to the Sun and not as hard
25:20
Speaker 1: on the other side of the planet that's further from
25:22
Speaker 1: the Sun, and so that affects the shape of the planet.
25:25
Speaker 1: It causes these tides, these squeezing of the planet, and
25:28
Speaker 1: that affects its spin. But it also has another opposite effect,
25:33
Speaker 1: and that it heats up the air on the planet,
25:36
Speaker 1: so it heats up the air on one side more
25:38
Speaker 1: than on the other side, and that causes really complex
25:42
Speaker 1: atmospheric tides on the planet. Like the shape of the
25:45
Speaker 1: Earth's atmosphere changes as we go around the Sun, m
25:49
Speaker 1: and that can actually change the rotation of the planet. Yeah,
25:54
Speaker 1: differential heating of the atmosphere can cause like a shape
25:57
Speaker 1: difference on the planet, and it can cause differential rag
26:00
Speaker 1: on the planet. And so these two things. It's very complicated,
26:03
Speaker 1: and people still don't even really agree on how this
26:06
Speaker 1: is all working their complex models. But for example, we
26:09
Speaker 1: think that the reason that Venus rotates so slowly is
26:12
Speaker 1: that this is some sort of like balance between these
26:15
Speaker 1: gravitational effects and these atmospheric effects. That's that's come to
26:19
Speaker 1: balance Venus in this weird state, all right. And so
26:22
Speaker 1: it's not just how fast are spinning that is different
26:25
Speaker 1: between the planets. It's also like how they're spinning right
26:27
Speaker 1: and which direction they're spinning, Yeah, because one of them
26:31
Speaker 1: out there is totally crazy, like urine Iss is tilted
26:34
Speaker 1: ninety degrees. Most of the planets are spinning around an
26:38
Speaker 1: access that's parallel to the axis that the Sun is spinning,
26:40
Speaker 1: and right, the Sun is like the major player here,
26:43
Speaker 1: and everybody's following its lead. But urine is it spins
26:46
Speaker 1: around an access that's tilted like ninety degrees. It's spinning
26:50
Speaker 1: around an access that's that's like flat. With the Solar system,
26:53
Speaker 1: it's like laying down decide it's doing its own thing.
26:58
Speaker 1: And that's fascinating because you wonder like, well, what does
27:01
Speaker 1: that mean, Where did that come from? Why is that happening?
27:04
Speaker 1: And the typical story is that, oh, maybe Uriness was
27:07
Speaker 1: like hit by some really big object, because to change
27:11
Speaker 1: the spin, you need some sort of external force. Right,
27:13
Speaker 1: an object that's just spinning can't change its spin without
27:16
Speaker 1: some sort of external torque, something that's going to change
27:19
Speaker 1: its angular momentum. So you imagine like some object coming
27:22
Speaker 1: from deep space and smacking into it and changing its spin.
27:25
Speaker 1: And that's a possible explanation, but scientists don't actually think
27:29
Speaker 1: that's the most likely explanation. I see. The it is
27:32
Speaker 1: that they all started spinning the same way, like all
27:35
Speaker 1: the planets were spinning in the same direction. But if
27:38
Speaker 1: it's not, then something must have happened. Something must have happened. Yeah,
27:43
Speaker 1: And the problem with the story that it's like one
27:45
Speaker 1: really big collision that's smacked Urinus and knocked it over.
27:48
Speaker 1: Uriness seems to have kept its moons. If there was
27:51
Speaker 1: one really big collision that that was big enough to
27:53
Speaker 1: knock Urnus over really suddenly, then it probably would have
27:57
Speaker 1: lost its moons, which just gone flying out into space instead.
28:00
Speaker 1: To keep your moons and tilt over, you need some
28:03
Speaker 1: sort of like gradual process. So they're imagining now some
28:06
Speaker 1: sort of like a series of smaller collisions that like
28:09
Speaker 1: knock it a little bit, and knock it a little bit,
28:11
Speaker 1: knock it a little bit, doing it gradually so you
28:14
Speaker 1: don't lose the moons. Interesting, now, are the moons spinning
28:17
Speaker 1: in the same way that the planet is spinning or
28:20
Speaker 1: is it totally different. Most of the moons do spin
28:24
Speaker 1: the same direction the planets are spinning, and the same
28:27
Speaker 1: direction the planets are going around the Sun, but not
28:29
Speaker 1: all of them. And there's too many moons in the
28:31
Speaker 1: Solar System to even count for. And these big planets
28:34
Speaker 1: have lots of moons, and so there's definitely some crazy
28:37
Speaker 1: behavior there too many moons, I like that phrase, and
28:41
Speaker 1: that's something. There's one planet that even rotates backwards, like
28:44
Speaker 1: it spins the wrong way Yeah, that's Venus. Venus is
28:48
Speaker 1: going the other direction, you know, Like, first of all,
28:51
Speaker 1: it's bonkers that Venus takes so long to rotate. You know,
28:54
Speaker 1: it takes two hundred and forties something days to rotate,
28:57
Speaker 1: which is about as long as it takes for it
28:59
Speaker 1: to go around the Sun, which means that like a
29:02
Speaker 1: day on Venus is about the same as a year
29:05
Speaker 1: on Venus, means like, you know, it's always your birthday
29:09
Speaker 1: on Venus, or always your anniversary if you live on Venus. Nice.
29:13
Speaker 1: It's a lot of birthday kids you have to buy,
29:17
Speaker 1: but you have all data planet right, which turns out
29:19
Speaker 1: to be it's one long party in Venus. It is
29:23
Speaker 1: one long party. But yeah, it's going the other direction, right,
29:27
Speaker 1: It's it's spinning the opposite direction from its motion around
29:31
Speaker 1: the Sun. All right, So, um, it seems that most
29:37
Speaker 1: things are spinning in the Solar system. But now to
29:39
Speaker 1: get back to our question is, um, what would happen
29:42
Speaker 1: if the Earth stop spinning? What would happen if we
29:45
Speaker 1: weren't spinning the way we are? Now? This is not
29:47
Speaker 1: something I recommend you actually exploring, Supervillain Council, because this
29:51
Speaker 1: would be pretty bad and it depends a little bit
29:55
Speaker 1: on what you mean by the Earth stop spinning, Like,
29:57
Speaker 1: is it just the rock of the Earth that's stop
30:00
Speaker 1: spinning all of a sudden, or is the whole planet,
30:02
Speaker 1: including like the oceans and the atmosphere also stops spinning,
30:06
Speaker 1: right and all. It also depends on how fast it
30:08
Speaker 1: stops spinning, right, Like, are we hitting the brakes? Is
30:13
Speaker 1: Superman suddenly like putting its thumb on the Earth and
30:17
Speaker 1: making it stop, or are we talking about like over
30:20
Speaker 1: centuries or even years? Yeah, exactly. So the most dramatic
30:25
Speaker 1: scenario is like if the Earth stopped spinning basically immediately
30:29
Speaker 1: Superman pulls the brakes, and he only does so on
30:32
Speaker 1: like the surface of the Earth and its internals. In
30:35
Speaker 1: that case, you have some pretty dramatic effects because now
30:38
Speaker 1: the air is moving at a really high velocity relative
30:41
Speaker 1: to the ground. Before you stop the spinning, the ground
30:45
Speaker 1: and the air are both rotating around the center of
30:48
Speaker 1: the Earth. But the earth stops, then all of a sudden,
30:51
Speaker 1: the atmosphere is moving across the Earth instead of just
30:54
Speaker 1: sitting on it, and at pretty high speeds. Right. Yeah,
30:57
Speaker 1: Like if you stop the rock of the Earth, the
31:00
Speaker 1: everything on it would still keep on spinning. That's the problem,
31:04
Speaker 1: including the I guess starting with the atmosphere, but also
31:07
Speaker 1: us exactly also us, And it depends on where you
31:11
Speaker 1: are on the Earth. If you're at the equator, then
31:14
Speaker 1: the spinning of the Earth moves your holes or conference
31:16
Speaker 1: to the earth like twenty four thousand miles in twenty
31:19
Speaker 1: four hours. That means you're going at a thousand miles
31:22
Speaker 1: per hour, and all of a sudden the rock under
31:25
Speaker 1: you stops. Then basically you're moving at a thousand miles
31:29
Speaker 1: per hour relative to that rock. That doesn't sound good. Basically, Yeah,
31:34
Speaker 1: it'd be like being in a in a in a
31:36
Speaker 1: crash kind of you get launched in the direction of
31:39
Speaker 1: the spin. You get launched in the direction of the spin,
31:42
Speaker 1: and you would smack right into stuff around you, right,
31:45
Speaker 1: and so it'd be pretty dangerous. The world around us
31:47
Speaker 1: is not built for humans traveling through a thousand miles
31:50
Speaker 1: per hour, right, And you know, like the houses would
31:53
Speaker 1: stay attached to the rock presumably or maybe maybe not actually,
31:58
Speaker 1: but most of the stuff would stay attached to the rock.
32:01
Speaker 1: But then the wind would be basically going into thousand
32:04
Speaker 1: miles per hour. Yeah, my house is not strong enough
32:08
Speaker 1: to sustain a thousand mile per hour shock, but maybe
32:11
Speaker 1: yours is. But if you imagine that your house somehow
32:14
Speaker 1: does stay attached to the earth, then it's suddenly moving
32:17
Speaker 1: through the atmosphere at a thousand miles per hour, And
32:19
Speaker 1: a thousand miles per hour is a very strong wind,
32:23
Speaker 1: stronger than any hurricane, and it would basically just scour
32:26
Speaker 1: the Earth smooth at the equator, though only at the equator. Yes,
32:31
Speaker 1: at the equator. If you're at the north pole, then
32:34
Speaker 1: there's no wind, right because at the north pole, you're
32:37
Speaker 1: not moving across the surface of the Earth. You're spinning
32:40
Speaker 1: like you know, a top. But if that stopped, there'd
32:43
Speaker 1: be no relative velocity to the air. What if I'm
32:46
Speaker 1: pretty far up north, like a Norway or Canada, do
32:50
Speaker 1: I have had some good chances of survival there there?
32:52
Speaker 1: Or is it still pretty dramatic? Depends a little bit
32:55
Speaker 1: on how dependent you are and the rest of the
32:57
Speaker 1: Earth's economy. But you know, I think the mobal devastation
33:00
Speaker 1: would be such that, like society would collapse, you might
33:03
Speaker 1: immediately survive, you know, goes up like with some Trigg
33:07
Speaker 1: function of your latitude. Um So nor would definitely be
33:10
Speaker 1: more survivable than you know, equatorial Guinea. Alright, so that's
33:15
Speaker 1: if the Earth suddenly stops spinning. Um, what else would happen?
33:21
Speaker 1: What if it wasn't sudden? I think it's much more
33:24
Speaker 1: interesting to consider like an actual physical scenario where the
33:27
Speaker 1: Earth stops spinning more gradually and to think about, like
33:30
Speaker 1: what would life be like on Earth that has like
33:32
Speaker 1: very gradually come to a screeching halt and not spinning
33:36
Speaker 1: where everything and it survives technically, uh, nothing gets destroyed immediately? Um, now,
33:44
Speaker 1: and like now, what would the what would life on
33:46
Speaker 1: Earth be like if we weren't spinning? Yeah, and there's
33:50
Speaker 1: some pretty interesting effects like well, first is the obvious stuff,
33:53
Speaker 1: like well, there's no more day and night, right. Your
33:56
Speaker 1: vision of the sun seeing it only twelve hours a
33:59
Speaker 1: day is because the Earth is spinning and it turns
34:01
Speaker 1: the Sun behind the back of the Earth. But if
34:04
Speaker 1: the Earth is no longer spinning, then your days are
34:07
Speaker 1: not twelve hours long, they're like six months long. M M.
34:12
Speaker 1: Now with that affect like temperatures, like when one side
34:16
Speaker 1: of the Earth get roasted if it had a six
34:18
Speaker 1: month day and the other side would get frozen. Yeah, absolutely,
34:23
Speaker 1: it's like having summer but without a break. Right in
34:26
Speaker 1: the summer, it can get pretty hot because you're tilted
34:28
Speaker 1: towards the sun. But then you get a break and
34:31
Speaker 1: when the earth rotates and you get nighttime for things
34:33
Speaker 1: to cool off. But in this scenario where the Earth
34:36
Speaker 1: doesn't spin, you have like six months continuously of hot
34:41
Speaker 1: summer days, and so the temperature variations would be much
34:44
Speaker 1: more dramatic than they are now. So the seasons would
34:47
Speaker 1: get exaggerated, right, But would they get that would get
34:51
Speaker 1: hot and too hot for us to live in, like
34:53
Speaker 1: with it just roast everything on the daytime side of
34:57
Speaker 1: the earth, or would it just be a a long
35:00
Speaker 1: day and we would be okay, you just have to
35:02
Speaker 1: wear more sun block. Um Well, on average, the same
35:06
Speaker 1: amount of energy would fall on the Earth's surface, so
35:09
Speaker 1: you'd have colder winters and warmer summers, and so the
35:12
Speaker 1: peak temperatures would definitely be more extreme because it would
35:15
Speaker 1: be time for the temperature to build up day upon
35:18
Speaker 1: day upon day. But you're not gonna be like roasting
35:20
Speaker 1: humans when they go outside. It's just going to get
35:22
Speaker 1: more uncomfortable. And then there will be portions of the
35:25
Speaker 1: Earth that maybe inhabitable because they get too hot practically speaking, right,
35:30
Speaker 1: And I guess the biology would have to adapt to,
35:33
Speaker 1: like plants would have to get these to only getting
35:35
Speaker 1: sun six months of the year. Yeah, it's incredible how
35:38
Speaker 1: much of our ecosystems and how much of the biology
35:41
Speaker 1: on Earth is linked to this cycle of day and night.
35:44
Speaker 1: It tells you not only that it would be devastating
35:47
Speaker 1: for that it stopped, but that has been going on
35:49
Speaker 1: for a long long time, you know, so much of
35:52
Speaker 1: life on Earth depends on this cycle, assumes this cycle,
35:55
Speaker 1: which means it's probably never really been disrupted. Yeah, I
35:59
Speaker 1: guess you what, what what happened? Would you need um, Like,
36:02
Speaker 1: would all the plants die six months of the year
36:04
Speaker 1: and then come back the other six months or would
36:06
Speaker 1: they just do you think they would just adapt? Well,
36:08
Speaker 1: there are some plants, right that do die every six
36:12
Speaker 1: months and just go back to their roots and then regrow,
36:15
Speaker 1: and so plants that can do that would survive. So yeah,
36:18
Speaker 1: plants that need sun, you know, more than every six
36:21
Speaker 1: months would definitely die off, and we'd be left with
36:23
Speaker 1: a subset of plants that can survive this kind of
36:26
Speaker 1: weird environment, and then they would you know, evolve and
36:28
Speaker 1: grow to fill all those niches. So we'd have very
36:31
Speaker 1: different foliage on Earth. If you stop the earth and
36:33
Speaker 1: spinning and then waited like a thousand years, you'd have
36:36
Speaker 1: a very different collection of plants. Some of them, for sure,
36:39
Speaker 1: would survive well. I certainly would look forward to not
36:42
Speaker 1: having to work six months out of the year. That
36:44
Speaker 1: sounds pretty good, like be nailed. Just sticking for six
36:49
Speaker 1: months sounds sounds pretty good right now. But you might
36:53
Speaker 1: have to plan your vacations differently because the whole surface
36:56
Speaker 1: of the Earth would look different if the Earth wasn't spinning. Yeah,
36:59
Speaker 1: what do you mean, um, Like the continents would be different. Yeah,
37:03
Speaker 1: the continents would be different because the distribution of water
37:06
Speaker 1: would be different. Water responds differently than land does to spin.
37:10
Speaker 1: Water is liquid, of course, it's much more deformable, and
37:13
Speaker 1: so as you spin the Earth, the water tends to
37:16
Speaker 1: bulge up near the equators. And so that's the spinning
37:19
Speaker 1: of the Earth that keeps more water at the equator
37:22
Speaker 1: than at the poles. And if the Earth stops spinning,
37:25
Speaker 1: and then that water sort of resettles and a lot
37:27
Speaker 1: of it moves from the equator out to the poles.
37:31
Speaker 1: What so Wait, are you saying that that the water
37:34
Speaker 1: is deeper or taller near the equator than near the poles.
37:39
Speaker 1: Distance from sea level to the center of the Earth
37:42
Speaker 1: is greater at the equator than it is at the poles.
37:45
Speaker 1: And so if you stopped spinning of the Earth, that
37:48
Speaker 1: of course would equilibrate, and so a lot of water
37:50
Speaker 1: would flow to the poles. And what you get is
37:53
Speaker 1: basically two massive polar oceans, right, huge vast oceans near
37:58
Speaker 1: the poles, and then like a big supercontinent at the equator.
38:02
Speaker 1: Whoa meaning um forget about Norway. Then in Canada maybe
38:08
Speaker 1: like they may have survived the earth stop stop Earth
38:12
Speaker 1: hitting the brakes, but they're not going to survive the floods. Maybe, Yeah. Exactly,
38:17
Speaker 1: North Dakota now becomes you know, ocean front property. Oh
38:21
Speaker 1: and Panama becomes much bigger. That's good, exactly exactly Panama
38:27
Speaker 1: becomes much bigger. Wow, So it would reshape the map.
38:30
Speaker 1: It would totally reshape the bap exactly. You know when
38:33
Speaker 1: you look at the surface of the Earth, but you're
38:34
Speaker 1: seeing only, of course, is the land that peaks above
38:37
Speaker 1: the surface of the water. As if you change the
38:40
Speaker 1: water level, you're going to change the edges of the continents,
38:42
Speaker 1: as you're gonna change really what the Earth looks like.
38:45
Speaker 1: Are there numbers for that, like how much would the
38:47
Speaker 1: sea level change at the equator? Is it like hundreds
38:50
Speaker 1: of feet or several feet? Well, the distance from the
38:54
Speaker 1: center of the Earth the sea level is twenty kilometers
38:57
Speaker 1: greater at the equator than at the pole, so it
39:00
Speaker 1: would definitely make a dramatic effect. Mm hmm. Alright, let's
39:05
Speaker 1: get into some other fun consequences of the Earth stopping
39:09
Speaker 1: its spin and what might actually make it stop. But
39:13
Speaker 1: first let's take another quick break. All right, we're talking
39:29
Speaker 1: about the Earth stopping it's spin, and so far it's
39:34
Speaker 1: not good. I mean, longer naps perhaps you know, uh,
39:39
Speaker 1: new beach front property in North Dakota. But overall it
39:44
Speaker 1: doesn't sound good. And that's not even the worst that
39:46
Speaker 1: can happen. That's not even the worst exactly. The worst
39:50
Speaker 1: maybe is that you would all gain weight if the
39:52
Speaker 1: Earth stopped spinning. That's the worst. What depends on your
39:56
Speaker 1: personal priorities. But you know, part of your weight is
40:00
Speaker 1: the earth gravity pulling down on you. But there's a
40:03
Speaker 1: counteracting force there. There's the spin of the Earth helps
40:07
Speaker 1: gently push you away from the center of the Earth
40:10
Speaker 1: the same way that like the Earth's motion around the
40:13
Speaker 1: Sun is what prevents it from falling into the Sun.
40:16
Speaker 1: Is this centripetal force that pushes in the opposite direction,
40:20
Speaker 1: and the earth spin contributes to that. So if the
40:23
Speaker 1: Earth stops spinning, then there would only be the force
40:25
Speaker 1: of gravity and you would feel it more. There would
40:28
Speaker 1: be no counteracting force there. Wait, what are you saying
40:31
Speaker 1: that I weigh more in Panama than I do at
40:33
Speaker 1: the North Pole. Oh no, wait, I weigh less in
40:36
Speaker 1: Panama than I do in the North Pole, and weigh
40:38
Speaker 1: more in the North Pole. Yeah, that's right, because you're
40:41
Speaker 1: feeling the Earth's spin more in Panama than you are
40:44
Speaker 1: at the North Pole. So that's why you gain weight
40:46
Speaker 1: every time you go to Norway. Right, it's not just
40:49
Speaker 1: the snacks, the cold fish and and blubber you keep
40:55
Speaker 1: eating me there, Yeah, exactly. And if you did the opposite,
40:58
Speaker 1: if you spun the Earth faster, if you if you
41:01
Speaker 1: convince Superman to spin the Earth much much faster, if
41:03
Speaker 1: you've got it to spend eighteen times faster, So that
41:07
Speaker 1: only took like an hour and a half of the
41:08
Speaker 1: Earth to spin all the way around, then you would
41:11
Speaker 1: be witless on the surface of the Earth. We wouldn't
41:14
Speaker 1: just stop spinning. We might even lose our magnetic field. Yeah,
41:17
Speaker 1: if you stop the Earth from spinning, you would really
41:19
Speaker 1: play unpleasant games with what's going on inside the Earth.
41:23
Speaker 1: We talked a minute ago about how some of the
41:25
Speaker 1: planets have differential rotation, like parts of them are rotating
41:29
Speaker 1: at different speeds. That's actually kind of key because that
41:32
Speaker 1: might be what helps drive the magnetic field of the Earth. Remember,
41:36
Speaker 1: magnetic fields come from things moving in circles, usually like
41:39
Speaker 1: currents of charge or in this case, hot lava or
41:43
Speaker 1: melted metals that are flowing in these big currents inside
41:46
Speaker 1: the Earth. And we think that the magnetic field might
41:49
Speaker 1: come from the fact that those currents don't flow at
41:51
Speaker 1: the same speed as the Earth. But it's vital that
41:54
Speaker 1: those things are spinning. And if the Earth stopped spinning,
41:56
Speaker 1: it might slow or change that rotation. But it might not.
42:01
Speaker 1: To write like, maybe we could stop spinning, but the
42:04
Speaker 1: stuff inside of the Earth could keep churning. It could
42:08
Speaker 1: write it depends on what Superman is doing. If he's
42:10
Speaker 1: only pushing on the crust, right and he lets the
42:13
Speaker 1: stuff inside keep spinning. But if he's got some power
42:16
Speaker 1: to stop everything inside the Earth from spinning, if you
42:19
Speaker 1: like froze the Earth so that nothing in it was
42:22
Speaker 1: moving and it wasn't spinning, then you would kill the
42:24
Speaker 1: magnetic field, and then we'd be toast. And then we'd
42:28
Speaker 1: be toast. Yeah, because our magnetic field is really important.
42:32
Speaker 1: It's literally a force field that protects us from solar radiation.
42:36
Speaker 1: The Sun is constantly shooting out an enormous stream of
42:39
Speaker 1: protons and electrons and other crazy stuff and bombarding us
42:43
Speaker 1: with it, and the magnetic field deflects all that stuff.
42:46
Speaker 1: Yeah alright, so, um, it doesn't sound great. Let's hope
42:50
Speaker 1: we keep on spinning. Let's pay the ransom to the
42:54
Speaker 1: supervillain if they actually do threaten to stop the Earth
42:56
Speaker 1: from a billion dollars. Sounds like a good good value there. Yeah,
43:01
Speaker 1: everybody puts in twenty cents, and hey, we can save
43:04
Speaker 1: the planet. Right, Yeah, there you go. Now, um, what
43:07
Speaker 1: are some of the things that might actually make the
43:09
Speaker 1: Earth stop? Could this actually happen? I mean, of course
43:12
Speaker 1: Superman is not going to come and stop the Earth,
43:14
Speaker 1: because first of all, he's a good guy and the
43:17
Speaker 1: second of all, it doesn't exist. But is this a
43:20
Speaker 1: realistic scenario at all? Like could the Earth stop spinning
43:24
Speaker 1: one day? Eventually? Maybe? Maybe eventually. And if we look
43:28
Speaker 1: on really long time scales, we do see that there
43:30
Speaker 1: are some processes there that are changing the way the
43:34
Speaker 1: Earth spins. So, for example, we have a moon that's
43:37
Speaker 1: rotating around the Earth, and those two things are not separate.
43:41
Speaker 1: The Moon is exerting our gravitational force on the Earth,
43:43
Speaker 1: just like the Earth exerts force on the Moon, and
43:46
Speaker 1: that causes some weird friction, Like the Moon is squeezing
43:49
Speaker 1: the Earth. That changes the shape of the oceans, and
43:52
Speaker 1: that causes some friction with the surface of the Earth.
43:56
Speaker 1: And so what's happening is that the Moon is sort
43:58
Speaker 1: of stealing some of our rotational speed. By doing this,
44:02
Speaker 1: it means that the Moon is getting further and further out.
44:05
Speaker 1: So we're losing the Moon about a centimeter per years,
44:07
Speaker 1: getting further and further away. And to compensate for that,
44:11
Speaker 1: to conserve angular momentum, the Earth is slowing down. Whoa
44:16
Speaker 1: meaning like the like we're losing energy to the moon,
44:20
Speaker 1: And yeah, we're losing energy to the moon. It's called
44:23
Speaker 1: tidal friction. It's not happening very fast. It's like every
44:27
Speaker 1: century a day is two milliseconds longer. In one century
44:31
Speaker 1: and a hundred years, it will take two more milliseconds
44:34
Speaker 1: for the Earth to complete one rotation. So it's not
44:37
Speaker 1: something that's really going to change your life or my
44:39
Speaker 1: life where our kids lives. But I feeling it live
44:41
Speaker 1: as more sluggish as I get older, Daniel, Could that
44:45
Speaker 1: be part of the effect of the moon. Yeah, I
44:48
Speaker 1: think you're slowing down the rotation of the Earth. Um,
44:51
Speaker 1: But it means that like in a hundred and forty
44:54
Speaker 1: million years, our days will be twenty five hours instead
44:58
Speaker 1: of twenty four hours, so you'll get that extra hour
45:01
Speaker 1: to get all your stuff done. Two milliseconds that could
45:04
Speaker 1: then that could make a big difference. It really adds up.
45:08
Speaker 1: So that's a real thing that's happening, and it is
45:11
Speaker 1: gradually slowing down the spin of the Earth. And so
45:13
Speaker 1: you know, forty million years you slow down by an hour.
45:17
Speaker 1: After a billion years you slow down by ten hours
45:19
Speaker 1: or so, or eight hours after that. It doesn't really
45:22
Speaker 1: make sense to make predictions because at that point the
45:25
Speaker 1: Sun is going to expand and absorb the Earth. Anyway,
45:27
Speaker 1: And so it doesn't really matter how fast we're spinning
45:29
Speaker 1: at that point. It's going to be sunlight twenty four hours,
45:33
Speaker 1: no matter the twenty six hours, no matter what. That's right,
45:37
Speaker 1: But there are also other things that are happening here
45:39
Speaker 1: on Earth that are changing the rate of the Earth
45:41
Speaker 1: spin like a like in real time, like real time.
45:46
Speaker 1: It turns out that if you just move stuff around
45:48
Speaker 1: on the Earth, if you shift enough chunks of Earth around,
45:52
Speaker 1: you can change how fast the Earth is spinning, sort
45:54
Speaker 1: of like a figure skater on the ice. If she
45:57
Speaker 1: pulls her arms in, she spins faster. If she moved
46:00
Speaker 1: her arms out, she spins more slowly. So if you
46:02
Speaker 1: rearrange chunks of Earth you can have the same effect.
46:06
Speaker 1: And this kind of stuff happens every time there's like
46:08
Speaker 1: a really big earthquake. Yeah, it happened recently, right, like
46:12
Speaker 1: the Japan quake. Yeah, the two thousand eleven quake in
46:15
Speaker 1: Japan moved enough Earth towards the equator that it's sped
46:19
Speaker 1: up our rotation by one point eight microseconds because the
46:24
Speaker 1: Earth got less less spread out or more spread out.
46:28
Speaker 1: So to speed up something that's rotating, you need to
46:31
Speaker 1: move stuff closer to the axis of rotation, so that
46:34
Speaker 1: it would have to spin faster to have the same
46:36
Speaker 1: Anglar momentum. So I guess this means that it moved
46:39
Speaker 1: a bunch of Earth closer to the poles, which I
46:42
Speaker 1: guess would mean moving it away from the equator. Actually, wow,
46:45
Speaker 1: So does that Does that mean Daniel that if everyone
46:47
Speaker 1: on Earth suddenly laid down at the same time, would
46:52
Speaker 1: that make the Earth spin faster? Or if we all
46:55
Speaker 1: jumped up at the same time, would that make the
46:58
Speaker 1: Earth slowed down for a second? Yeah? Actually, I think
47:00
Speaker 1: the Earth would spin faster if everybody laid down, or
47:03
Speaker 1: if everybody like went underground into the subway, or if
47:06
Speaker 1: everyone went to the equator. Right, Yeah, everyone went to
47:10
Speaker 1: the equator. That would slow the Earth down. Let's do it, Daniel.
47:14
Speaker 1: Let's start a movement. Jorg is paying for everybody to
47:17
Speaker 1: go to Panama, make the day longer. Let's all moved
47:22
Speaker 1: to Panama. There you go. And at the same time,
47:26
Speaker 1: there are effects from the Sun, Like the Sun is
47:28
Speaker 1: having these tidal effects on mercury and venus. But we're
47:31
Speaker 1: also pretty close to the Sun, and so the Sun
47:34
Speaker 1: is sort of trying to do to us. What we
47:36
Speaker 1: are doing to the moon. Remember that the rotation of
47:39
Speaker 1: the Moon is not free. It's not just like doing
47:42
Speaker 1: whatever it likes. It's locked to the Earth because of
47:45
Speaker 1: these tidal forces. Earth is like squeeze the Moon a
47:48
Speaker 1: little bit, and it's tugging on the part of the
47:50
Speaker 1: Moon that's closer to it, so it keeps the Moon
47:52
Speaker 1: from rotating freely, which is why we always see one
47:56
Speaker 1: side of the Moon when we look up. Well, the
47:58
Speaker 1: Sun is trying to do the same thing to us.
48:00
Speaker 1: It's trying to lock the Earth's rotation, tugging on it
48:04
Speaker 1: so that the same surface always faces the Sun. And
48:07
Speaker 1: so if that happens far far in the future, that
48:09
Speaker 1: would mean something crazy. That would mean not just that
48:11
Speaker 1: the Earth stops spinning, but if there's like a dark
48:14
Speaker 1: side of the Earth and a light side of the Earth.
48:16
Speaker 1: All right, So it doesn't sound um like it's happening
48:20
Speaker 1: anytime soon, Daniel. It's not something we have to worry
48:23
Speaker 1: about anytime soon, barring a superman and maybe like a
48:28
Speaker 1: meteor hitting us, but then we would have other things
48:31
Speaker 1: to worry about. That. Yeah, if there's a massive collision
48:34
Speaker 1: with enough energy to like hit the Earth and stop
48:37
Speaker 1: it's spinning. Then we're anyway going to get devastated and
48:39
Speaker 1: our atmosphere is gonna be roasted to the fact that
48:42
Speaker 1: our destroyed corpse of a planet is no longer spinning. Afterwards,
48:45
Speaker 1: it's not really going to be the LEAs of how long,
48:48
Speaker 1: how long our day is? All right, well, it's still
48:53
Speaker 1: it's sort of interesting to think about, you know, kind
48:56
Speaker 1: of what we take for granted, you know, the Earth spinning.
48:59
Speaker 1: You know, we always think that there's going to be
49:00
Speaker 1: a tomorrow, but that's not necessarily true, no, exactly. And
49:05
Speaker 1: this kind of thing, the earth spinning, it's not necessarily
49:08
Speaker 1: something that's gonna last forever, and it's sort of an artifact.
49:12
Speaker 1: It just sort of depends on the original chunk of
49:14
Speaker 1: stuff that became the Earth, how fast it was spinning.
49:16
Speaker 1: We could have lived on a planet with a twelve
49:18
Speaker 1: hour day or thirty six hour day, twenty four hours.
49:21
Speaker 1: It's not fundamental, it's really quite accidental. Yeah, so it
49:25
Speaker 1: sort of really makes you appreciate not just the day,
49:28
Speaker 1: but the idea of the day. All right, Well, we
49:31
Speaker 1: hope you enjoyed that. Hoping got you to think a
49:33
Speaker 1: little bit about your place in the world and what's
49:36
Speaker 1: happening right underneath your feet. Thanks for joining us, see
49:40
Speaker 1: you next time. Thanks for listening, and remember that Daniel
49:50
Speaker 1: and Jorge explained. The Universe is a production of I
49:53
Speaker 1: Heart Radio. Or more podcast for my heart Radio, visit
49:56
Speaker 1: the I heart Radio app, Apple Podcasts, or were ever
50:00
Speaker 1: you listen to your favorite shows.