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Is the whole Universe spinning? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Daniel, do you ever get frustrated by, you know,
0:11
Speaker 1: asking the biggest questions in the universe all the time? Never?
0:15
Speaker 1: I live for it. I mean, what could be more fun?
0:18
Speaker 1: How about finding the answers sometimes? Oh? There are always
0:22
Speaker 1: answers out there waiting for us to discover them. You know, really,
0:26
Speaker 1: you think all the big questions in the universe have
0:29
Speaker 1: answers to them? What if they don't. I think that
0:31
Speaker 1: even the deepest, hardest, craziest questions in the universe have answers,
0:35
Speaker 1: and one day some human will know them. Hopefully that
0:38
Speaker 1: human is you or one of our listeners. What if
0:40
Speaker 1: the big questions don't have answers? You mean, like, is
0:43
Speaker 1: white chocolate really chocolate? Can you just say? I don't know.
0:46
Speaker 1: That's what I told my kids all the time. That's
0:48
Speaker 1: an answer, right? How about ask your mother? Is that
0:50
Speaker 1: an answer to the question? Who ate all the chocolate?
0:53
Speaker 1: That one is also asked your mother? Hi? I'm poor
1:10
Speaker 1: Hammy car Tennis and the creator of PhD comics. Hi,
1:13
Speaker 1: I'm Daniel. I'm a particle of physicist and a professor
1:16
Speaker 1: at UC Irvine, and I will continue to eat chocolate
1:19
Speaker 1: until all the questions are answered. I thought you were
1:21
Speaker 1: going to say that you you ate all the chocolate,
1:24
Speaker 1: but I guess you still have answers to find. That's right.
1:26
Speaker 1: As long as they keep making chocolate, I'll keep asking
1:28
Speaker 1: questions and looking for answers. I'm not sure where this
1:31
Speaker 1: correlation between answers and chocolate came from, Daniel, Are you
1:34
Speaker 1: sure you're not just making it up? I'm not making
1:36
Speaker 1: that up. You know that there's a tight correlation between
1:38
Speaker 1: the amount of chocolate consumed per capita and the number
1:42
Speaker 1: of Nobel prizes one per capita for countries Switzerland is
1:46
Speaker 1: like knocking it out of the park. Isn't that weird? Though?
1:49
Speaker 1: Isn't the Nobel price based out of Switzerland? No, it's Sweden, man,
1:53
Speaker 1: Hello Sweden. Wrong as w country were. Clearly, Sweden just
1:58
Speaker 1: needs to be more chocolate. Clearly, everybody needs to eat
2:01
Speaker 1: more chocolate. I mean, it's good for everything. It's good
2:04
Speaker 1: for your mind, it's good for your soul. I'm not
2:05
Speaker 1: sure it's good for your waistline or your heart a
2:09
Speaker 1: little bit. That's a true correlation, right like that. If
2:12
Speaker 1: you make a plot of the countries that have Nobel
2:15
Speaker 1: Prizes and the amount of chocolate they eat per capita. Supposedly,
2:18
Speaker 1: I mean I haven't looked into the data, but supposedly
2:20
Speaker 1: there's a correlation, right, Yeah, I think we have a
2:22
Speaker 1: plot of that in the opening of one of our books.
2:24
Speaker 1: So the data is there, the correlation is true. The causality,
2:28
Speaker 1: I'm not exactly sure. It doesn't mean that you should
2:31
Speaker 1: force feed chocolate to your school children in order to
2:33
Speaker 1: get Nobel prizes in twenty years. You mean, like the
2:36
Speaker 1: causality could be the other way around, Like winning a
2:39
Speaker 1: lot of Noble prices could cause you to eat a
2:41
Speaker 1: lot of chocolate. Yeah. Maybe they're just celebrating their Noble
2:44
Speaker 1: prizes by eating chocolate, right, Or maybe there's a chemical
2:46
Speaker 1: and chocolate. It could be big chocolate, you know, just
2:49
Speaker 1: be a big conspiracy, Oh, conspiracy between big chocolate and
2:53
Speaker 1: big Nobele. Yeah, the big science and big chocolate. They're
2:58
Speaker 1: already trying to make us all bigger. I guess that's
3:01
Speaker 1: right exactly. We're asking bigger questions by making our scientists
3:05
Speaker 1: even bigger, especially around the waistline. I occupy a larger
3:08
Speaker 1: and larger fraction in the universe every year, that's right.
3:11
Speaker 1: If you occupy larger fractions of the universe. There's less
3:13
Speaker 1: of the universe to explore. Technically speaking, Yeah, well that
3:17
Speaker 1: must be what dark matter is. After all, it's just
3:20
Speaker 1: overweight physicists. I guess eating dark chocolate because white chocolate
3:25
Speaker 1: not chocolate. Maybe that's what happened out in space, like
3:27
Speaker 1: all these aliens that are more advanced, you know, sort
3:30
Speaker 1: of reach the chocolate singularity and just based out of
3:35
Speaker 1: the electronic neetic spectrum. See how much progress we've made already.
3:38
Speaker 1: I don't think anybody ever said the phrase chocolate singularity before.
3:42
Speaker 1: So that's progress right there, chocolate fuel progress. Yeah, just
3:46
Speaker 1: talking about chocolate makes even a noble price boom. But anyways,
3:50
Speaker 1: welcome to our podcast, Daniel and Horror Explain the Universe,
3:52
Speaker 1: a production of I Heart Radio in which we eat
3:55
Speaker 1: our way towards answers to some of the biggest, tastiest,
3:58
Speaker 1: most delicious question humans have ever asked. Questions about the
4:02
Speaker 1: size of the universe, the shape of the universe, the
4:05
Speaker 1: motion of the universe, the fundamental nature of the reality
4:08
Speaker 1: we find ourselves in as curious conscious beings trying desperately
4:12
Speaker 1: to understand what's going on and where is my next
4:15
Speaker 1: piece of chocolate? Coming from that's right, because the universe
4:18
Speaker 1: is full of amazing and incredible things like delicious snacks
4:22
Speaker 1: and dark matter and sometimes dark delicious snacks at all
4:25
Speaker 1: at the same time, and we're all just wondering what's
4:28
Speaker 1: going on, what's out there, and how does it work.
4:31
Speaker 1: And some of us get to do that for a living.
4:33
Speaker 1: I mean, ask questions, not each chocolate. Nobody pays me
4:36
Speaker 1: to do that yet, but it does fuel my curiosity
4:39
Speaker 1: about the fundamental nature of what things are like out there. Yeah,
4:42
Speaker 1: I guess you're a professional question asker, Daniel. Would you
4:45
Speaker 1: say that's that's how you can describe a researcher. Yeah.
4:48
Speaker 1: Everybody who have decided to spend their life doing science
4:51
Speaker 1: has done so because there's a question that drives them.
4:54
Speaker 1: Of course, I'm curious about lots of questions in science
4:57
Speaker 1: that I don't personally work on, But everybody who's a
4:59
Speaker 1: scientist has their own personal questions that drive them to
5:03
Speaker 1: spend their life asking it. You know. Maybe it's about
5:06
Speaker 1: how birds communicate and choose partners. Maybe it's about how
5:10
Speaker 1: the Earth was formed. Maybe it's about the fundamental nature
5:13
Speaker 1: of space and time. It's this personal curiosity that drives
5:17
Speaker 1: science forward. Yeah, and you forgot the very important question
5:20
Speaker 1: how do you make chocolate fat free? That would also
5:22
Speaker 1: move signs forward a lot. Apparently, you mean, how do
5:25
Speaker 1: you make chocolate chocolate free? How do you make chocolate
5:30
Speaker 1: still delicious but a little healthier? Maybe? Yeah, The answer
5:33
Speaker 1: that one is you can't. The unhealthiness is part of
5:36
Speaker 1: why it's so delicious. Oh, I say, it's the guilty
5:39
Speaker 1: pleasure of it that you like. Oh my goodness, it's
5:42
Speaker 1: just got a little extra dark. But I guess. Yeah,
5:45
Speaker 1: you're a professional question asker, which means you're also sort
5:48
Speaker 1: of a professional head spinner, right, because I mean your
5:50
Speaker 1: job is not just to answer questions that your job
5:52
Speaker 1: is to find answers to crazy questions and find crazy
5:56
Speaker 1: answers right to leave people's head spinning. That's right. Sometimes
5:59
Speaker 1: when you under these deep questions about the universe, you wonder, like,
6:03
Speaker 1: how can we even get started? How do we take
6:05
Speaker 1: that first step towards that future where some human knows
6:09
Speaker 1: the answer to those questions as like an actual fact.
6:12
Speaker 1: Sometimes it can be inconceivable to probe such big questions
6:16
Speaker 1: and know like how to get started. Yeah, and hopefully
6:19
Speaker 1: it's a future we're not just one human not the answer.
6:22
Speaker 1: Hopefully that person gets to tell other humans yes. But
6:25
Speaker 1: there's always a first human, right. That's the joy of discovery,
6:28
Speaker 1: to be the first person to know something about the
6:31
Speaker 1: universe that nobody else knows, just like there was a
6:34
Speaker 1: first person to taste every kind of fruit on Earth,
6:37
Speaker 1: or first person to see every single mountain or to
6:40
Speaker 1: walk along a beach. There's always a first and that's
6:42
Speaker 1: the joy of discovery. You want to be the one
6:45
Speaker 1: who figures it out, not reading about it in the
6:47
Speaker 1: science times of the newspaper, right right, Although the way
6:50
Speaker 1: science works, you're never quite the first human, right because
6:52
Speaker 1: you always need things to be pu reviewed, right, like
6:55
Speaker 1: somebody needs to check your answer. You can't just like
6:57
Speaker 1: come up with an idea and have absolute certain that
7:00
Speaker 1: it's true, can you. You can't ever certain. But there
7:03
Speaker 1: are moments when you do an experiment and the results
7:06
Speaker 1: are just very conclusive. These moments of discovery where you've
7:09
Speaker 1: designed your experiment in a way to like corner the
7:11
Speaker 1: universe to revealing some truth to you. That a podcast
7:15
Speaker 1: about pulsar discovery last year in which we played audio
7:18
Speaker 1: of the astronomers watching the data come in in real
7:21
Speaker 1: time and having that moment of discovery. They almost shouted
7:24
Speaker 1: eureka live on the tape. So sometimes there really are
7:27
Speaker 1: those moments when you know something about the universe. Yeah,
7:32
Speaker 1: I guess you. Then you want to be the first
7:33
Speaker 1: human to be with like you know something. But it
7:38
Speaker 1: does leave your head spinning. This search for truth and
7:40
Speaker 1: the cosmos and searching for the idea of how things
7:44
Speaker 1: work in the explanation for why things are the way
7:46
Speaker 1: they are, including some very interesting questions about whether or
7:50
Speaker 1: not things are even spinning in the first place. That's right,
7:54
Speaker 1: because we see lots of things spinning in the universe.
7:56
Speaker 1: We know the Earth is spinning, and the Earth is
7:58
Speaker 1: spinning around the Sun, which is spinning around the center
8:01
Speaker 1: of the galaxy, which is itself spinning, which is moving
8:04
Speaker 1: around the center of the galaxy cluster. And so naturally,
8:07
Speaker 1: as a curious human being, you wonder how far does
8:10
Speaker 1: that spinning go? Yes, So to be on the program,
8:12
Speaker 1: we'll be asking the question, is the whole universe spinning? So, Daniel,
8:22
Speaker 1: how are we spinning? This question is the question it's
8:25
Speaker 1: self spinning? Is that what you're saying? This question definitely
8:28
Speaker 1: makes my head spin. And it's been one that's been
8:30
Speaker 1: debated sort of on the boundary of physics and philosophy
8:34
Speaker 1: for a few hundred years. You know, not just the
8:37
Speaker 1: question of is our universe spinning? But could it be spinning?
8:40
Speaker 1: What does it mean or the whole universe to spin
8:43
Speaker 1: spinning relative to what you know? Could you even tell
8:47
Speaker 1: if the whole universe was spinning? It's really fascinating question
8:51
Speaker 1: that tells us a lot about the nature of space
8:54
Speaker 1: itself and what is absolute and what is relative? Right,
8:57
Speaker 1: Because I guess you can, you know, ask if ace
9:00
Speaker 1: itself is spinning, right, because you know, we know sort
9:03
Speaker 1: of spaces kind of a thing that can bend and
9:05
Speaker 1: twist and ripple. What if the space itself is turning around? Well,
9:08
Speaker 1: you just blew my mind? Man? Did I make your
9:11
Speaker 1: head spin? Didn't make you want to eat more chocolate?
9:16
Speaker 1: That's always the case. That's a pretty low standard. But yeah,
9:19
Speaker 1: you can ask questions like is the stuff in space spinning?
9:23
Speaker 1: Is space itself spinning? What would space itself be spinning?
9:27
Speaker 1: Relative to? All sorts of really fun, big, mind blowing
9:31
Speaker 1: head spinning questions are involved. Well, I guess the question
9:34
Speaker 1: we're asking today is the universe spinning. So really we're
9:37
Speaker 1: we're asking about the whole shebanging like everything right. Yeah,
9:41
Speaker 1: now here's another one, Daniel, Is the multiverse spinning, It's
9:47
Speaker 1: definitely spinning money for the Marvel Universe. The Marvel Universe
9:52
Speaker 1: is spinning out cash. Yeah, they're shooting out of Spider
9:56
Speaker 1: Man's spinning web shooters. If the universe is spinning, and
10:01
Speaker 1: that spin is random, then you can imagine there might
10:03
Speaker 1: be a whole set of universes which each have their
10:05
Speaker 1: own different random spin. And then if we measured our
10:08
Speaker 1: universe to have a particular spin, we could ask like, well,
10:10
Speaker 1: why this spin not some other spin? You can add
10:13
Speaker 1: the multiverse that basically any questions, But then the multiverse
10:16
Speaker 1: would would be infinite and it would average out to
10:18
Speaker 1: nothing or not. I think this conversation is spinning out
10:22
Speaker 1: of control. Dinner, let's get back on track here. Yes, So,
10:27
Speaker 1: as usually, we were wondering how many people out there
10:29
Speaker 1: had thought about this spinning question, whether or not the
10:32
Speaker 1: whole universe is spinning or not, And so Daniel went
10:35
Speaker 1: out there into the wilds of the Internet to ask
10:37
Speaker 1: people the question, is the whole universe spinning? And thanks
10:41
Speaker 1: again to our cadre of volunteers who participate in these
10:45
Speaker 1: difficult to answer questions without any chance to do any googling.
10:49
Speaker 1: If that sounds fun to you and you'd like to
10:51
Speaker 1: hear your voice on the podcast, we would love to
10:53
Speaker 1: hear from you, So please don't be shy. It's free,
10:56
Speaker 1: it's easy, it's fun right to us. Two questions at
10:59
Speaker 1: Daniel and Joge dot com. Think about it for a second.
11:02
Speaker 1: Do you feel or think that the universe around you
11:06
Speaker 1: is spinning? Here's what people had to say. It wouldn't
11:10
Speaker 1: surprise me if the whole universe is spinning because so
11:13
Speaker 1: many things are spinning. You know, we're on a spinning
11:17
Speaker 1: Earth that, in turn is revolving around the Sun, which
11:21
Speaker 1: in turn is revolving around the galaxy, and the galaxy
11:24
Speaker 1: itself is spinning, and then our galaxy is probably spinning
11:29
Speaker 1: around other galaxies in the local group, which then uh
11:34
Speaker 1: itself probably is spinning within the bigger group. Well, I
11:37
Speaker 1: feel like we know it's expanding, but I have no
11:40
Speaker 1: idea if I've heard that it's spinning or not. Everything
11:43
Speaker 1: else in the universe is spinning, so why wouldn't the
11:46
Speaker 1: universe spin? Yes, without question, the universe is definitely spinning.
11:52
Speaker 1: There's a center of gravity, But I don't think that
11:56
Speaker 1: there is a center of gravity across the entire universe.
12:04
Speaker 1: I think there are local galactic clusters that rotate um,
12:09
Speaker 1: but yeah, because they share a center of gravity, I
12:12
Speaker 1: don't think that there's a center of gravity across the universe.
12:15
Speaker 1: So I'm going to say, no, it's not. Spin is
12:18
Speaker 1: a little relative, right, So in order for it to
12:22
Speaker 1: be spinning, it would need to be spinning relative to
12:26
Speaker 1: something outside the universe. So that's really a question. Is
12:33
Speaker 1: there anything outside the universe for which the universe could
12:38
Speaker 1: be spinning? When I think about the universe, I think
12:41
Speaker 1: of everything like it's just a word that is sort
12:46
Speaker 1: of all encompassing, and I I don't know if if
12:50
Speaker 1: we were, if the universe is all encompassing, what would
12:52
Speaker 1: it be spinning relative to? Is it that, like space
12:55
Speaker 1: itself spinning? Which doesn't make a lot of intuitive sense
12:58
Speaker 1: to me. I mean, you could probably figure out if
13:00
Speaker 1: it was spinning using I don't know, like the Michaelson
13:03
Speaker 1: Morley experiment with like the the the ether or whatever
13:06
Speaker 1: you can like test for that kind of a thing.
13:07
Speaker 1: I guess if the whole universe was spinning, then everything
13:12
Speaker 1: were be moving at the same time. So I don't
13:14
Speaker 1: know how we'd be able to tell, but maybe it is.
13:18
Speaker 1: All right, a wide range of answers. Some people said yes,
13:22
Speaker 1: no hesitation there, yes it's spinning. We got the whole
13:26
Speaker 1: range of answers here. We got from yes it's spinning
13:28
Speaker 1: to what does that even mean? To how could you
13:31
Speaker 1: even tell? It? Really pretty much represents the entire spectrum
13:34
Speaker 1: of possible answers, right, even a little bit of a
13:37
Speaker 1: maybe there, maybe it's spinning. So it's a fascinating question,
13:40
Speaker 1: is the whole universe spinning? And so let's get into
13:43
Speaker 1: the particulars of that question. I have questions about it, Daniel,
13:47
Speaker 1: could uh could the university spinning? It's a really interesting
13:50
Speaker 1: question just to ask, like what does that mean? First
13:53
Speaker 1: of all? Right, like could the university spinning? Spinning? Relative
13:56
Speaker 1: to what we've talked on this podcast for a while
13:59
Speaker 1: about real activity, you know, we talked to Carlo Rovelli,
14:02
Speaker 1: for example, about relative motion, and he made a really
14:05
Speaker 1: interesting point that we've talked about a few times that
14:07
Speaker 1: if you, for example, lived in the universe all by yourself,
14:10
Speaker 1: there's nothing else in the universe, then velocity would have
14:14
Speaker 1: no meaning. Because velocity is purely a relative quantity. You
14:18
Speaker 1: can only be moving relative to other stuff, and so
14:22
Speaker 1: in an empty universe, velocity has no meaning. Wait, what
14:25
Speaker 1: if the like the universe has a like an extent,
14:28
Speaker 1: you know what I mean, like a border or an edge,
14:29
Speaker 1: then you could be being relative to that even if
14:32
Speaker 1: you were alone in the universe. In our understanding of relativity,
14:35
Speaker 1: space is isotropic and homogeneous, meaning there are no special
14:38
Speaker 1: locations in space. The kind of cosmology you're talking about
14:41
Speaker 1: where there are special locations in space would break a
14:45
Speaker 1: lot of the rules that we think we understand, you know,
14:47
Speaker 1: like conservation of momentum. And so for now, let's operate
14:51
Speaker 1: in a universe that's essentially either infinite in extent or
14:53
Speaker 1: where every location in space is the same. So you
14:57
Speaker 1: can't be moving just relative to space. You have to
14:59
Speaker 1: be moving relative to other stuff in space. So from
15:02
Speaker 1: that point of view, you can't ask questions like is
15:05
Speaker 1: the whole universe moving? Right now, imagine the universe filled
15:10
Speaker 1: with stars and galaxies just like ours. It doesn't make
15:13
Speaker 1: sense to ask is all of that stuff moving? Because
15:16
Speaker 1: it would have nothing to move relative to if you're
15:18
Speaker 1: talking about the whole universe. So from that point of view,
15:21
Speaker 1: things like you know, velocity are purely relative. And the
15:25
Speaker 1: question then is like, is the same thing true for spin?
15:29
Speaker 1: If you were alone in a universe, all by yourself,
15:32
Speaker 1: an empty space, could you tell if you were spinning? Right?
15:36
Speaker 1: Because velocity, like you're saying, is relative, but acceleration is
15:39
Speaker 1: not relative. Right, Like, you could also ask the question
15:41
Speaker 1: is the universe accelerating? And that one would have meaning
15:44
Speaker 1: right because moving could also apply to acceleration. Yes, velocity
15:48
Speaker 1: is purely relative, but acceleration is absolute. Some you can
15:52
Speaker 1: measure the acceleration of an object. If you were alone
15:54
Speaker 1: in the universe, you could build a little device that
15:57
Speaker 1: would tell you whether or not you were accelerating. And
15:59
Speaker 1: it's not a complicated device. You could just like have
16:01
Speaker 1: a ball in a box and hold it steady. If
16:04
Speaker 1: the ball moves towards one side, it means you are
16:06
Speaker 1: accelerating in the other direction. That's just how an accelerometer works.
16:11
Speaker 1: Or if you're inside a box, you can tell whether
16:14
Speaker 1: you're accelerating because you would feel an effective gravity against
16:17
Speaker 1: one side or the box. Right, So you can build
16:19
Speaker 1: an accelerometer. You don't have to be accelerating relative to
16:22
Speaker 1: any other thing. You can be accelerating relative to absolute
16:25
Speaker 1: space time. It's interesting the history of how we came
16:28
Speaker 1: to these realizations. The first person to think about this
16:31
Speaker 1: question whether spin is absolute or relative? You know, can
16:36
Speaker 1: you be spinning relative to space or do you have
16:38
Speaker 1: to spin relative to other stuff? Was actually Isaac Newton, Right, yeah,
16:42
Speaker 1: because where I guess the question is whether or not
16:44
Speaker 1: we're spinning or not, and that one can be relative, right,
16:47
Speaker 1: or not relative. So that was a question, if you're spinning,
16:50
Speaker 1: what are you spinning relative to Are you spinning relative
16:52
Speaker 1: to space or are you only spinning relative to other
16:55
Speaker 1: stuff out there in the universe? Right, So it's spin
16:58
Speaker 1: sort of like acceleration or is it more like velocity?
17:02
Speaker 1: And at the time, of course of Newton, Newton thought
17:05
Speaker 1: that velocity was absolute, that you were moving relative to
17:08
Speaker 1: space itself. But he proposed a really fun thought experiment
17:11
Speaker 1: as a way to sort of like measure whether or
17:13
Speaker 1: not you're spinning and basically, like you know, a spinometer
17:16
Speaker 1: in the same way you can build an accelerometer to
17:18
Speaker 1: see if you're accelerating. He thought, let's build an experiment
17:21
Speaker 1: that measures whether or not you're spinning. And it's pretty simple.
17:24
Speaker 1: You take a bucket of water, and you know the
17:26
Speaker 1: surface of the water is flat, and then you start
17:29
Speaker 1: spinning the bucket and you spin it sort of along
17:31
Speaker 1: its access You could like twist a rope on the
17:33
Speaker 1: handle or something like that. Now, what happens, of course,
17:35
Speaker 1: is that the bucket starts spinning, and then eventually the
17:38
Speaker 1: water gets dragged along by the buckets, and now the
17:40
Speaker 1: water is also spinning. And what happens is that the
17:42
Speaker 1: water gets pushed up against the sides of the buckets.
17:45
Speaker 1: So the surface of the water is no longer flat.
17:48
Speaker 1: It's now concave. And so this, he says, is a
17:50
Speaker 1: way to measure whether or not you're spinning, because even
17:53
Speaker 1: if you're like on the bucket, if you're like an
17:55
Speaker 1: ant on the bucket, you can still tell that it's concave.
17:59
Speaker 1: Right every it you will agree that the surface of
18:01
Speaker 1: the water is now concave. So it's like a way
18:03
Speaker 1: to measure the fact that you are spinning, right, It's
18:06
Speaker 1: sort of like it's trying to measure whether or not
18:08
Speaker 1: there are centripetal acceleration or forces on you because like,
18:12
Speaker 1: if you're spinning, something must be causing you to to
18:15
Speaker 1: spin to change directions all the time, and that's what
18:18
Speaker 1: the centripetal acceleration is. Yes, centripe tol acceleration is pulling
18:22
Speaker 1: you towards the center's changing your velocity vector so you're
18:25
Speaker 1: moving in a circle. For example, centrifugal acceleration is the
18:29
Speaker 1: fictional force that you feel because you're in a non
18:32
Speaker 1: inertial reference frame, so that the ant, for example, or
18:35
Speaker 1: the water feels that force pushing them outwards. You know,
18:37
Speaker 1: the same way. For example, if you are on a
18:39
Speaker 1: spaceship out in deep space and it was spinning, you
18:42
Speaker 1: would feel an effective gravity. You'd be able to walk
18:44
Speaker 1: along the inside of that spinning can as if there
18:47
Speaker 1: was gravity. This is one plan for having effective gravity
18:51
Speaker 1: and deep spaces. Make your spaceships spin, right. So Newton thought, well, obviously,
18:55
Speaker 1: then spin is absolute right that you're spinning relative to
18:59
Speaker 1: spa ace, because you can build this thing that measures it.
19:02
Speaker 1: And even if you were in the frame of the bucket,
19:05
Speaker 1: if you were spinning with the bucket, you could still
19:07
Speaker 1: tell that the bucket was spinning. So now imagine that
19:10
Speaker 1: bucket in deep and empty space. You should be able
19:12
Speaker 1: to tell whether you're spinning or not based on whether
19:15
Speaker 1: the water is concave or whether it's flat. So Newton
19:18
Speaker 1: was like, I'm very sure that spin is absolute, meaning
19:22
Speaker 1: that you could tell maybe if the universe, the whole universe,
19:25
Speaker 1: was spinning, right, like if we were just sitting here
19:27
Speaker 1: and we felt this in tripital exceloration um, even though
19:30
Speaker 1: nothing seemed to be moving, then maybe you could tell
19:33
Speaker 1: that the everything was spinning exactly. And if spin is absolute,
19:37
Speaker 1: then you could measure the spin of the universe, right,
19:39
Speaker 1: because the whole universe could be spinning in space, and
19:43
Speaker 1: if that was happening, according to Newton, you could measure it.
19:46
Speaker 1: But not everybody agreed with Newton. There was a guy
19:49
Speaker 1: named Ernst Mock who came along and said, no, no, no,
19:52
Speaker 1: that's not true at all. Spin is purely relative. Motion
19:56
Speaker 1: is relative, after all, right, like if you're moving through space,
19:58
Speaker 1: that's purely relative. So Mark said, maybe everything is relative,
20:03
Speaker 1: maybe all motion in the universe, acceleration and velocity, and
20:06
Speaker 1: this is before relativity, right before Einstein said maybe everything
20:10
Speaker 1: is relative. And then people said, well, what about the bucket, right,
20:13
Speaker 1: the bucket can tell if you're rotating, and Mark said, well,
20:16
Speaker 1: the bucket is rotating relative to the stars out there.
20:20
Speaker 1: That's why the surface of the bucket gets concave, because
20:23
Speaker 1: it's rotating not relative to space, but to the stars
20:26
Speaker 1: out there in the universe. That doesn't make a lot
20:29
Speaker 1: of sense. It doesn't make a lot of sense to
20:30
Speaker 1: me either. But remember, at the time, people didn't really
20:33
Speaker 1: understand the notion of space and time and relativity, and
20:36
Speaker 1: these questions were sort of up in the air, you know.
20:38
Speaker 1: People wanted to know, for example, if velocity is relative,
20:41
Speaker 1: as we all accept, then why isn't acceleration relative? Like
20:45
Speaker 1: you said it earlier that velocity is relative but acceleration
20:48
Speaker 1: is not. But why not? And at the time people
20:50
Speaker 1: didn't understand, and so this was sort of a beautiful
20:53
Speaker 1: idea to say, well, maybe everything is actually relative, and
20:56
Speaker 1: the reason that the surface of the bucket gets concave
20:59
Speaker 1: is somehow because of the distant stars. And on the
21:02
Speaker 1: other side, people say, well, that's ridiculous, Like, are you
21:04
Speaker 1: saying that if you spun a bucket in empty space
21:07
Speaker 1: that it would stay flat? Right? He said, absolutely, If
21:10
Speaker 1: you spin your bucket and then you start removing the
21:12
Speaker 1: stars out there in the universe that the surface of
21:15
Speaker 1: the bucket would go from concave to flat, that somehow
21:19
Speaker 1: those distant, distant stars are telling the bucket surface what
21:22
Speaker 1: to do. I feel like MOK should have stuck to
21:24
Speaker 1: like sound research, maybe not trying to do astronomy here.
21:29
Speaker 1: But I guess you're saying that's kind of the thinking
21:31
Speaker 1: at the time, like maybe if you sort of like
21:33
Speaker 1: removed a reference frame, and maybe that's kind of what
21:36
Speaker 1: he was getting at. It's like, if you remove the
21:38
Speaker 1: reference frame of the stars, then somehow, um, maybe you
21:42
Speaker 1: lose all relativity. Yeah. Max said that spinning is relative.
21:45
Speaker 1: If you're not spinning relative to something else, then you're
21:48
Speaker 1: not spinning. Spinning in an empty universe has no meaning
21:51
Speaker 1: that you could never tell. You know that if you
21:53
Speaker 1: were in an empty universe and I started to spin you,
21:55
Speaker 1: you wouldn't feel your arms get pushed out towards the side.
21:58
Speaker 1: If you build a spaceship and spun it in an
22:00
Speaker 1: empty universe, you wouldn't feel effective gravity that comes somehow
22:04
Speaker 1: from the distant stars that are defining a reference frame.
22:07
Speaker 1: And this was a beautiful idea, and even Einstein liked that.
22:10
Speaker 1: Einstein thought Oh, this sounds really nice, and he tried
22:13
Speaker 1: really hard to work it into his theory of relativity,
22:16
Speaker 1: because I think the idea was that motion is relative, right,
22:19
Speaker 1: like everything is relative. So Einstein basically came up later
22:21
Speaker 1: and said, actually, turns out Newton is wrong and also
22:24
Speaker 1: Mock is wrong. They're both wrong in slightly different ways.
22:28
Speaker 1: All right, Well, let's get into how Einstein proved them
22:30
Speaker 1: wrong and whether or not the whole universe is spinning,
22:34
Speaker 1: because my head is spinning a little bit right now,
22:36
Speaker 1: and I kind of made a little break, so we'll
22:39
Speaker 1: be right back. All right, we're asking the question is
22:54
Speaker 1: the whole universe spinning? I am getting a little dizzy
22:57
Speaker 1: just thinking about and talking about this question. And where
23:00
Speaker 1: we left off was that Einstein looked at Newton and
23:03
Speaker 1: then he looked at another researcher back in the day,
23:06
Speaker 1: and he said, um, you're both wrong. Actually, maybe spinning
23:10
Speaker 1: is also relative. So Einstein said, definitely, Newton is wrong,
23:14
Speaker 1: because Newton said that all motion is absolute, that space
23:18
Speaker 1: is like its own absolute frame, and velocity is absolute,
23:22
Speaker 1: that in an empty universe and object moving in his
23:24
Speaker 1: train line, you could somehow measure its velocity relative to
23:27
Speaker 1: absolute space. So Einstein said, no, that's ridiculous. There is
23:31
Speaker 1: no preferred location in space, There is no preferred velocity
23:35
Speaker 1: in space. That doesn't make any sense. And he built
23:37
Speaker 1: that into his theory of relativity. But he also said
23:40
Speaker 1: that Mack was wrong because Mak wanted to go even
23:42
Speaker 1: further and say, well, even acceleration is relative, and Einstein
23:46
Speaker 1: liked that idea, but he found that it didn't actually work.
23:49
Speaker 1: And so what Einstein says is that space is relative.
23:52
Speaker 1: And we've talked up on the podcast a few times
23:54
Speaker 1: about how time is relative. Also different observers in the
23:58
Speaker 1: universe feel timed differently. But when you put the two together,
24:02
Speaker 1: space time, you actually do get something absolute. Einstein didn't
24:06
Speaker 1: actually like calling his theory relativity theory because he thought
24:10
Speaker 1: it oversawled the relativity aspect of it. He wanted to
24:12
Speaker 1: call it invariance theory. But anyway, what he found was
24:15
Speaker 1: that space is relative and time is relative, but that
24:19
Speaker 1: space time together had some absolutes in it that lets
24:23
Speaker 1: you measure whether something is accelerating, and spinning counts as accelerating.
24:29
Speaker 1: So acceleration and spin are absolute, but velocity is relative.
24:33
Speaker 1: I guess it sort of maybe depends on your definition, right,
24:36
Speaker 1: Like is spinning motion also motion, or is spinning motion
24:41
Speaker 1: like something that's not motioned, you know what I mean?
24:43
Speaker 1: Like maybe you're saying, you know, spinning involves acceleration, and
24:47
Speaker 1: therefore it's not sort of the same as moving with
24:50
Speaker 1: a constant velocity exactly. Spinning is definitely a kind of acceleration.
24:55
Speaker 1: So then the question really is is acceleration absolute. If
24:58
Speaker 1: acceleration is absolut if you can measure acceleration out in
25:01
Speaker 1: deep space, that means that spinning is absolute, that you
25:05
Speaker 1: could also measure spin in deep space. And so Einstein's
25:08
Speaker 1: theory of relativity shows us that velocity is relative, but
25:12
Speaker 1: that acceleration is absolute. That you can tell if an
25:15
Speaker 1: object is accelerating, which also means you can tell if
25:19
Speaker 1: it's spinning, right, which means that if you even if
25:21
Speaker 1: you were alone in the universe, you can still get dizzy.
25:23
Speaker 1: You can get dizzy in an empty universe. And we've
25:25
Speaker 1: seen this other times when we've talked about Einstein's theory
25:28
Speaker 1: of relativity and spin. Because Einstein's theory, for example, predicts
25:31
Speaker 1: a difference between the gravity of an object that's spinning
25:34
Speaker 1: a gravity of an object that's not spinning. A spinning
25:37
Speaker 1: object has this weird effect frame dragging, where like drags
25:41
Speaker 1: space along behind it a little bit. And Newton doesn't
25:44
Speaker 1: predict that because Newton says there's no difference between the
25:47
Speaker 1: gravity of a spinning object and a non spinning object,
25:50
Speaker 1: and that wouldn't make any sense if spinning was purely relative. Right,
25:53
Speaker 1: So spinning objects have a different gravitational effect, and therefore
25:56
Speaker 1: you must be able to tell the difference between spinning
25:58
Speaker 1: and non spinning objects, right, But I wonder if that
26:01
Speaker 1: is that something. I guess that's just kind of built
26:04
Speaker 1: into the laws of the universe that we that we
26:07
Speaker 1: can tell, Like why does the universe draw the line
26:09
Speaker 1: between velocity and acceleration, because you know, mathematically, it's just
26:14
Speaker 1: like one derivative over. It is just one derivative like
26:19
Speaker 1: it could have been acceleration is also invariant, but then
26:21
Speaker 1: the derivative of acceleration the next one over, is not relative.
26:25
Speaker 1: It does seem sort of arbitrary to like draw the
26:27
Speaker 1: line at the first derivative and not the second derivative.
26:30
Speaker 1: And there are a lot of really deep ideas here.
26:31
Speaker 1: One of them has to do with symmetry and conservation laws.
26:34
Speaker 1: We'll talk about that in an episode coming up soon
26:37
Speaker 1: on Nuther's Theorem. I think the best way to think
26:39
Speaker 1: about it is to think about what is invariant, what
26:41
Speaker 1: is preserved in the universe. The reason, for example, that
26:44
Speaker 1: you can tell that something is accelerating versus something is
26:48
Speaker 1: not is because of their path through space time. You know,
26:51
Speaker 1: this has to do with things like free fall. Right,
26:53
Speaker 1: if you are just moving through space without accelerating, you
26:56
Speaker 1: don't feel any forces, which you're effectively doing is making
26:59
Speaker 1: a straight line through space time. Like your path through
27:03
Speaker 1: space time is just a straight line. If you're accelerating,
27:06
Speaker 1: you like burn your rocket. If you're being pushed by something,
27:09
Speaker 1: then you make a curve in spacetime. So the reason
27:12
Speaker 1: that you can tell whether something is accelerating or not
27:15
Speaker 1: is because everybody agrees. All observers agree whether or not
27:18
Speaker 1: you're making a straight line in space time or a
27:21
Speaker 1: curve in spacetime. That's what it means to say that
27:23
Speaker 1: spacetime itself is absolute, that the universe can tell the
27:26
Speaker 1: difference between straight paths and spacetime and curved paths in spacetime. Well,
27:31
Speaker 1: I guess that's kind of what I mean, like, you know,
27:33
Speaker 1: you said, it's all sort of depends or it's all
27:36
Speaker 1: because of some symmetry in the universe. But then like,
27:39
Speaker 1: what if the universe they didn't have those symmetries, or
27:41
Speaker 1: what if we lived in another universe without those symmetries,
27:43
Speaker 1: would those RULs be different? Or is that invariant about
27:49
Speaker 1: the velocity and acceleration kind of baked into math itself.
27:53
Speaker 1: It's not baked in the math. You could construct cosmologies
27:56
Speaker 1: where things were different. This is the universe that we
27:58
Speaker 1: find ourselves in. These are the rule that we discover.
28:01
Speaker 1: You know. It's sort of like asking the question and
28:03
Speaker 1: why is momentum conserved? And the answer is space is
28:05
Speaker 1: the same everywhere? All right, well, why is this space
28:08
Speaker 1: the same everywhere? It's not required by mathematics. You could
28:11
Speaker 1: have a universe where the rules of physics vary from
28:14
Speaker 1: place to place. We just don't seem to have that universe.
28:17
Speaker 1: So this is sort of like a discovery of ours.
28:19
Speaker 1: The universe seems to obey this principle, and these are
28:22
Speaker 1: the consequences of that principle. Why does it obey this principle?
28:25
Speaker 1: We don't know, But we've discovered it. It's sort of
28:28
Speaker 1: like saying, okay, the speed of light is invariant for everybody.
28:31
Speaker 1: Everybody measures the speed of light to be the same. Why,
28:33
Speaker 1: we don't know, but here are the consequences of it.
28:36
Speaker 1: This is the invariance that Einstein discovered that space is
28:39
Speaker 1: not invariant, but space time is. You know. Another way
28:43
Speaker 1: to think about these paths is to think about like,
28:45
Speaker 1: you know, imagine how you get from your house to
28:47
Speaker 1: your work. Somebody could draw like a set of axes X,
28:50
Speaker 1: y Z and say Joge gets from his house to
28:52
Speaker 1: his work and from this coordinate to that coordinate. And
28:55
Speaker 1: somebody else could come along and say, well, I have
28:56
Speaker 1: a totally different set of coordinates for Jorges path from
29:00
Speaker 1: him to work, and those are totally different coordinates, but
29:02
Speaker 1: doesn't matter. And it doesn't matter because the path itself
29:06
Speaker 1: is the same. The two observers would look at the
29:08
Speaker 1: path and say, oh, it's a straight line or no,
29:10
Speaker 1: it's a wiggle because he stops at the fridge on
29:12
Speaker 1: the way from his bed to his cartooning studio. Right,
29:15
Speaker 1: So people agree about the shape of the path even
29:17
Speaker 1: if they don't agree about the actual coordinates. That's what
29:20
Speaker 1: it means that space time, your path through space time
29:24
Speaker 1: is absolute, even if your coordinates are arbitrary. Well sometimes
29:29
Speaker 1: I work from bed. Even everyone would agree that it's
29:33
Speaker 1: a short community. Yeah, exactly. If your path is a point,
29:35
Speaker 1: then everybody would agree. Yeah, that's the whole point of
29:38
Speaker 1: being a cartoonist is to live in a point. But
29:41
Speaker 1: I think what you're saying is that you know, it's
29:43
Speaker 1: sort of baked into the laws of at least this
29:45
Speaker 1: universe that we live in, that you can't tell if
29:48
Speaker 1: something is spinning, Like it's not something that you can hid,
29:51
Speaker 1: or it's not something that you can like maybe never tell.
29:54
Speaker 1: But the question we're asking today is whether the whole
29:56
Speaker 1: universe is spinning, which kind of makes me wonder, like
30:00
Speaker 1: feel like, now it could go either way, because yes,
30:02
Speaker 1: you can tell if something is spinning in the universe,
30:04
Speaker 1: but what if the universe itself is spinning? Could you tell? Here?
30:07
Speaker 1: I think we have to be careful about what we
30:09
Speaker 1: mean by the universe. And I'm talking now about the
30:12
Speaker 1: matter in the universe. Like I take all the stuff,
30:14
Speaker 1: the galaxies, the dust, the gas, the dark matter, is
30:18
Speaker 1: all of that stuff spinning and that here it's spinning
30:21
Speaker 1: relative to space time. Spacetime itself can that spin? Like, well,
30:25
Speaker 1: what would that be spinning relative too? There's no external
30:28
Speaker 1: metric for spacetime itself to spin. So we're talking about, like,
30:32
Speaker 1: you know, the Earth is spinning, is it possible that
30:34
Speaker 1: everything else is also spinning in that same way that
30:37
Speaker 1: the Earth is spinning? Oh? I see You're you've been
30:39
Speaker 1: spinning this question the whole time, Daniel. You're really asking
30:42
Speaker 1: is the whole stuff in the universe spinning? You're not
30:45
Speaker 1: asking if the universe is spinning. Well, it depends on
30:48
Speaker 1: whether you're including space time in that spin. And I
30:51
Speaker 1: would say it doesn't make sense for space time itself
30:54
Speaker 1: to spin, but stuff in space time can spin relative
30:58
Speaker 1: to space time. Well, I guess maybe let's explore that
31:01
Speaker 1: a little bit. Like we've talked about space being a thing,
31:03
Speaker 1: How do you know it's not spinning? It could be
31:05
Speaker 1: spinning even if it's not relative to anything. Right, the
31:08
Speaker 1: same way that we talked about expansion of spacetime, we
31:11
Speaker 1: don't say that spacetime is expanding into something else. We
31:14
Speaker 1: only have intrinsic measurements. We are in spacetime. There's nothing
31:18
Speaker 1: outside of space time to measure, so we can only
31:20
Speaker 1: measure internally. Right, So we say spaces expanding, people ask
31:24
Speaker 1: what is it expanding into? Well, it's not expanding into anything.
31:27
Speaker 1: It's just increasing the relative distances between stuff in space.
31:32
Speaker 1: So in the same way, you can't really ask what
31:35
Speaker 1: is spacetime rotating in It's not in anything. It just
31:39
Speaker 1: sort of is. And so there's no sense in which
31:41
Speaker 1: space time could spin. But I thought you were going
31:44
Speaker 1: the other way, because you know, you can say that
31:46
Speaker 1: space is expanding, but it's not expanding relative to anything.
31:50
Speaker 1: Couldn't I just say spacetime is spinning, but it's just
31:53
Speaker 1: not spinning relative to anything. Then what does that mean
31:55
Speaker 1: for it to be spinning? What does it mean for
31:56
Speaker 1: its expanding nothingness? It means that the distances between stuff
32:01
Speaker 1: are getting larger, right, But what does it mean for
32:04
Speaker 1: space time itself as a whole to spin? You can
32:07
Speaker 1: tell whether's something is spinning relative to space time same
32:10
Speaker 1: way you can tell whether you know distances are growing,
32:12
Speaker 1: but you can't tell whether spacetime itself is spinning. You
32:15
Speaker 1: could maybe, like maybe if I was alone in the
32:17
Speaker 1: universe and I got dizzy, you know what I mean?
32:20
Speaker 1: Like I guess what I'm wondering is, could there be
32:22
Speaker 1: like an inherent centripital acceleration to the universe. I think
32:26
Speaker 1: it's possible. Mathematically, there is always an ambiguity there, even
32:29
Speaker 1: in the case of expansion, because general relativity has this
32:32
Speaker 1: weird difficulty by talking about the velocities of things that
32:35
Speaker 1: are very far away, you always define either relative velocities
32:38
Speaker 1: or velocities relative to space. And so probably there's a
32:42
Speaker 1: way you could construct a universe that had a rotating
32:45
Speaker 1: space time that had an inherent built in centrifugal acceleration.
32:50
Speaker 1: You know, for example, a curvature of space would give
32:52
Speaker 1: you that effect if space was curved in such a
32:55
Speaker 1: way that you effectively felt a negative gravity. And there
32:58
Speaker 1: are some folks out there argue that dark energy may
33:02
Speaker 1: partially be due to some like inherent and trifugal force
33:06
Speaker 1: due to the rotation of space time itself, rather than
33:10
Speaker 1: some expansion of space. WHOA wait, so like the space
33:14
Speaker 1: and could be spinning and it might be the answer
33:17
Speaker 1: to dark energy. That's one thing people were probably and
33:19
Speaker 1: we'll talk about how people use type one a supernova
33:22
Speaker 1: to try to answer that question. You a little bit
33:24
Speaker 1: when we talk about how to measure whether space is spinning.
33:27
Speaker 1: All right, we'll leave that for another episode, but I
33:29
Speaker 1: guess in this episode we are now shifting the question too.
33:32
Speaker 1: Is everything in the universe in spacetime it's self spinning,
33:36
Speaker 1: because you know, it could be spinning, right Like, like
33:39
Speaker 1: you said earlier, the Earth is spinning, and we're spinning
33:41
Speaker 1: around the Sun, and the Sun is spinning around the
33:43
Speaker 1: gaxy and the GALSSI. It's probably spinning around some larger
33:47
Speaker 1: cluster of galaxies, and that could also be spinning relative
33:50
Speaker 1: to other clusters. You know, is everything may be spinning.
33:54
Speaker 1: It's a really fun question, and what we expect, what
33:56
Speaker 1: physics predicts, is sort of counterintuitive because on one hand,
34:00
Speaker 1: we see that everything is spinning, as you say, the
34:02
Speaker 1: Earth is spinning, of the galaxy is spinning, but we
34:04
Speaker 1: don't actually expect, on very very large scales for all
34:08
Speaker 1: the stuff in the universe to be spinning. That if
34:10
Speaker 1: you added up all the stuff in the universe, we
34:12
Speaker 1: actually predict that it should have zero spin, right because
34:15
Speaker 1: it seems kind of implausible almost that everything would not
34:20
Speaker 1: to be spinning, that it would be sort of standing still.
34:24
Speaker 1: It doesn't. It's actually a very specific prediction of inflation. Remember,
34:27
Speaker 1: inflation is this prediction that the universe started out much
34:30
Speaker 1: much denser, much much more compact, and then spread out
34:33
Speaker 1: and expanded and blew out, and that all the structure
34:36
Speaker 1: we see in the universe comes from like the little
34:38
Speaker 1: quantum fluctuations in density from the early universe. And it's
34:41
Speaker 1: that expansion itself that we think would have killed effectively
34:44
Speaker 1: any rotation. Remember what happens when you're spinning. If you're
34:48
Speaker 1: like on ice in your figure skater, if you pull
34:50
Speaker 1: your arms towards yourself, then you start to spin faster.
34:53
Speaker 1: And that's why, for example, the Earth is spinning because
34:55
Speaker 1: it started out from a cloud of stuff that was
34:57
Speaker 1: very gently spinning and then collapsed, and the is now
35:00
Speaker 1: spinning faster. But expansion has the opposite effect. So as
35:03
Speaker 1: the universe expands, we expected to spin less and less.
35:07
Speaker 1: Because inflation expanded the universe by like ten to the
35:10
Speaker 1: thirty than any tiny random rotation of that initial blob
35:14
Speaker 1: of stuff, we would expect that to be effectively zeroed
35:17
Speaker 1: out by inflation. Right, I guess maybe I'm getting a
35:20
Speaker 1: little confused here because of what we're actually asking, Like,
35:23
Speaker 1: I guess, are we asking whether all this stuff in
35:25
Speaker 1: the universe has a zero or non zero average spin?
35:30
Speaker 1: Do you know what I mean? Like, for sure I
35:32
Speaker 1: can spin in my chair here, and the Earth is
35:34
Speaker 1: for sure spinning, and the Sun is definitely spinning, and
35:37
Speaker 1: the galaxy and the galaxy clusters are definitely moving relative
35:40
Speaker 1: to other things. I guess is the question, like, if
35:43
Speaker 1: you average out everything, all the stuff in the universe,
35:46
Speaker 1: does it have a spin to it or does it
35:48
Speaker 1: all cancel out to exactly zero? Is that kind of
35:51
Speaker 1: what we're really asking here? Yeah, draw line through space
35:54
Speaker 1: and measure the spin relative to that line, and then
35:56
Speaker 1: ask is that overall spinning all the stuff in the universe?
36:01
Speaker 1: Is that zero or not? Right? Sort of like if
36:03
Speaker 1: you have a snow globe, maybe I'm thinking, you know,
36:06
Speaker 1: you can have all the snowflakes inside moving and twirling
36:08
Speaker 1: and looking chaotic, but overall you can sort of tell
36:12
Speaker 1: whether or not this stuff in it is spinning relative
36:15
Speaker 1: to the globe. What you're saying is that it maybe
36:18
Speaker 1: has to do with the beginning of the unse like
36:21
Speaker 1: if this stuff at the beginning of the universe had
36:23
Speaker 1: a little bit of a spin, that's the only way
36:26
Speaker 1: it could still have spin today, Yeah, because angular momentum
36:29
Speaker 1: is conserved. Right, If you are spinning, you will always
36:33
Speaker 1: be spinning. There's no way to stop something from spinning
36:36
Speaker 1: unless you're coming in from the outside with some other
36:38
Speaker 1: spin to cancel it out. If you're talking about the
36:40
Speaker 1: whole universe, then there is nothing outside and so if
36:43
Speaker 1: the whole universe somehow started out spinning, it should still
36:46
Speaker 1: be spinning today, although that spin would get dampened out
36:50
Speaker 1: and go to very very small values because of the
36:53
Speaker 1: expansion of the universe, like a figure skater shooting her
36:56
Speaker 1: arms out for like millions and millions of miles or spin,
36:59
Speaker 1: but then go to the to the zero. So that's
37:01
Speaker 1: what we're talking about, is is there spin to this
37:03
Speaker 1: stuff in the universe and it should persist if it's there, right,
37:06
Speaker 1: Because I think what you're saying is that the universe
37:08
Speaker 1: had no spin at the Big Bang when it was
37:10
Speaker 1: super super tiny small, and thence if it had no spin,
37:14
Speaker 1: there's no way for it to gain spin since then
37:18
Speaker 1: like it can't like push off against anything right to
37:22
Speaker 1: get spin. There's no way to spin the entire universe.
37:25
Speaker 1: There's nothing to like push against. Right. If you're talking
37:27
Speaker 1: about the whole universe is nothing that you can push against,
37:29
Speaker 1: because that would mean something outside the universe and the
37:31
Speaker 1: universe is everything, right, unless maybe, like spacetime itself has
37:35
Speaker 1: a like a lean, like a lean to it, right,
37:38
Speaker 1: or something, you know, like it has a preference for
37:40
Speaker 1: a matter and not antimatter. It has a preference for
37:43
Speaker 1: certain things, you know, four wards some time and not
37:45
Speaker 1: backwards some time. Could it also have like a little
37:47
Speaker 1: bit of a spin preference. Yeah, we usually ask this
37:49
Speaker 1: question under the assumption that spacetime is homogeneous, meaning it's
37:53
Speaker 1: the same everywhere and in every direction. But it's certainly
37:57
Speaker 1: possible if we discovered an overall spin to the universe
37:59
Speaker 1: to wonder that comes from and you know, could be
38:02
Speaker 1: generated by like some features in spacetime that aren't the
38:05
Speaker 1: same everywhere I see. But your your basic answer is
38:08
Speaker 1: that the stuff in the universe has any spin. Now,
38:11
Speaker 1: it must be due to any kind of spin it
38:13
Speaker 1: has at the beginning of the universe. But even if
38:15
Speaker 1: it had a little bit of a rotation at the
38:16
Speaker 1: beginning of the universe, that would have all sort of
38:19
Speaker 1: gone to almost zero by now. Yes, So we would
38:22
Speaker 1: be very surprised if we look out into the universe,
38:25
Speaker 1: measure its overall spin, and find it to be spinning
38:29
Speaker 1: at any significant rate. That would be a big shock.
38:31
Speaker 1: It would make all your head spin for sure, relative
38:34
Speaker 1: to all the chocolate you're eating. It would be a
38:36
Speaker 1: fantastic and delicious discovery because it would be a clue
38:39
Speaker 1: that's something we think is true, is not that there's
38:43
Speaker 1: something else going on that we don't understand, and like
38:45
Speaker 1: the biggest, most delicious scales. All right, well, let's get
38:49
Speaker 1: into how we could tell if the universe, or at
38:52
Speaker 1: least the stuff in the universe, is spinning at any
38:55
Speaker 1: significant rate, because I think Daniel is hungry, so let's
38:58
Speaker 1: get that answer asap. But first let's stick another quick break. Alright,
39:13
Speaker 1: we're talking about whether or not all this stuff in
39:15
Speaker 1: the universe is spinning, Dan, and you said it's unlikely
39:19
Speaker 1: for it to have any kind of spin, because expanding
39:22
Speaker 1: the universe would have killed any sort of momentum. But
39:25
Speaker 1: what if I'm thinking, what if the universe was spinning
39:28
Speaker 1: a lot at the beginning, couldn't it also have some
39:30
Speaker 1: sort of remnant spin twit at this point? Yeah, it would,
39:35
Speaker 1: and we might be able to measure that if we
39:37
Speaker 1: devise tests that are very very sensitive, and so you're
39:41
Speaker 1: right that the current theories of physics suggests that spin
39:44
Speaker 1: is dampened by expansion. But we don't have an idea
39:48
Speaker 1: for why the universe would or would not be spinning originally.
39:52
Speaker 1: So if the universe was somehow born spinning super duper fast,
39:55
Speaker 1: we could still measure that today, and that would be
39:57
Speaker 1: interesting because our cosmology allows for the universe to spin.
40:01
Speaker 1: It's possible for the whole universe to have been born spinning,
40:04
Speaker 1: for it to have been a spinning baby shot out
40:08
Speaker 1: of the universe womb and doing a triple lets. And
40:12
Speaker 1: remember we don't really know much about that birth. We
40:14
Speaker 1: talked about possible theories of like infloton fields decaying into
40:19
Speaker 1: normal matter. There's are really displaceholders for like where to
40:22
Speaker 1: have future ideas the shape of those ideas, but we
40:25
Speaker 1: definitely don't have ideas firm enough to where we can say, like,
40:28
Speaker 1: the universe should not have been born with any spin.
40:31
Speaker 1: For sure, there's a huge opening there for ways the
40:34
Speaker 1: universe could have been born and allowing for it to spin,
40:36
Speaker 1: And definitely Einstein's ther relativity says it is possible. It's
40:40
Speaker 1: meaningful for the stuff in the universe to be spinning, right,
40:43
Speaker 1: So I guess that means that if you do discover
40:46
Speaker 1: that all the stuff in the universe is spinning right now,
40:48
Speaker 1: it maybe shouldn't be that surprising. You'll just tell you
40:50
Speaker 1: if it was spinning at the beginning or not. It
40:52
Speaker 1: would tell you that it was spinning a lot at
40:54
Speaker 1: the beginning, and then you'd have to go into your
40:56
Speaker 1: theories and say, like, well, how do I make that happen?
40:59
Speaker 1: You know? Is it a diverse where the spin is
41:01
Speaker 1: somehow random and we just got a big serving of
41:03
Speaker 1: it is necessary because of some property of the universe beforehand,
41:07
Speaker 1: the universe is inherently always spinning. It would be a
41:10
Speaker 1: lot of really fun questions. Yeah, or maybe the universe
41:13
Speaker 1: mom just hit a lot of chocolate before the baby
41:17
Speaker 1: universe was born and made the baby universe spin out
41:22
Speaker 1: of control. All right, So then what are some of
41:24
Speaker 1: the ways that we could maybe test today, like where
41:27
Speaker 1: we are now in this spinning or not spinning universe,
41:30
Speaker 1: whether or not things are spinning everything, whether or not
41:32
Speaker 1: everything is spinning. So people have been thinking about this
41:35
Speaker 1: for decades, and remember Einstein's theory of relativity is only
41:37
Speaker 1: about a hundred years old. To this concept that the
41:40
Speaker 1: universe can spin absolutely relative to space time. He's only
41:44
Speaker 1: about a hundred years old, and it took a while
41:47
Speaker 1: for people to understand what it means. You know, Einstein
41:49
Speaker 1: actually believed Mark for decades until later in his life
41:52
Speaker 1: when he was like, no, beautiful, but I think he's wrong.
41:55
Speaker 1: And it's really only like fifty or so years that
41:57
Speaker 1: people have been are thinking about this in a way
41:59
Speaker 1: that they test it. And one of the simplest ideas
42:02
Speaker 1: is just like, well, let's just look and see if
42:04
Speaker 1: the universe appears to be spinning relative to some fixed point.
42:09
Speaker 1: You mean looking at all the stuff in the universe,
42:11
Speaker 1: not the universe itself. Yeah, all the stuff in the universe.
42:13
Speaker 1: And so, for example, are the galaxies, the distant galaxies?
42:16
Speaker 1: Are they spinning relative to the Milky Way or relative
42:20
Speaker 1: to the Solar System? And the cool thing is that
42:22
Speaker 1: you can treat the Solar System, because itself is spinning,
42:25
Speaker 1: as a sort of gyroscope. That the Solar System is spinning,
42:28
Speaker 1: and it's going to continue to spin, and because of
42:30
Speaker 1: conservation of Anglo momentum, it has to keep spinning and
42:33
Speaker 1: basically the same direction, so it like defines an access
42:37
Speaker 1: and then you can ask, well, is the rest of
42:39
Speaker 1: the universe sort of spinning around us relative to the
42:43
Speaker 1: Milky Way? What do you mean? I would that tell
42:45
Speaker 1: you if the universe was spinning, I mean the stuff
42:47
Speaker 1: in the universe was spinning. Well, it would tell you
42:49
Speaker 1: whether the universe was spinning relative to the Milky Way.
42:52
Speaker 1: At least we can measure the Milky Way spin, right,
42:55
Speaker 1: because we can tell whether an individual object needs spinning,
42:58
Speaker 1: and so that gives us like a reference point, and
43:00
Speaker 1: then we can ask whether the rest of the universe
43:02
Speaker 1: is spinning relative to us. So we can measure our
43:04
Speaker 1: spin relative to spacetime, and then we can measure the
43:07
Speaker 1: rest of the universe is spin relative to the Milky Way,
43:10
Speaker 1: just by looking at the galaxies and saying, like, are
43:12
Speaker 1: they moving relative to us? Oh? I see, But isn't
43:16
Speaker 1: that sort of a given, Like don't we expect the
43:18
Speaker 1: Milky Way to be, you know, spinning in some weird
43:21
Speaker 1: direction relative to everything else, all the stuff in the universe.
43:25
Speaker 1: We can measure the Milky Way spin relative to spacetime
43:27
Speaker 1: because it's absolute, and then we can measure the motion
43:30
Speaker 1: of the distance galaxies relative to the Milky Way, and
43:33
Speaker 1: if that's exactly the opposite, then that suggests that the
43:36
Speaker 1: whole rest of the universe is essentially not spinning. Oh,
43:39
Speaker 1: I see, Because you're saying that you can measure the
43:42
Speaker 1: spinning of stuff relatives to spacetime. There is sort of
43:45
Speaker 1: like a reference frame in the universe, and that's called
43:48
Speaker 1: space time. And you're saying, because the Milky Way is
43:50
Speaker 1: close to us, we can measure that pretty accurately. It
43:53
Speaker 1: gives us sort of a compass of how we're spinning
43:55
Speaker 1: relative to spacetime. And then you're saying, let's look at
43:58
Speaker 1: everything else and see if it's rotating relative to that exactly. So,
44:03
Speaker 1: say you're spinning around inside of a room, you can
44:06
Speaker 1: have a way to measure your own spin. You have
44:08
Speaker 1: like a gyroscope that tells you your own spin, and
44:11
Speaker 1: you can also measure your spin relative to the walls.
44:13
Speaker 1: So those two numbers agree, that tells you the walls
44:15
Speaker 1: are not spinning. Those two numbers disagree. That tells you, Oh, well,
44:18
Speaker 1: I guess the walls are also spinning. So that's what
44:20
Speaker 1: we can do. We can measure our spin of the
44:22
Speaker 1: Milky Way and then we can measure the spin of
44:24
Speaker 1: the Milky Way relative to the distant galaxies, and then
44:26
Speaker 1: we can ask are the distant galaxies spinning in absolute sense?
44:31
Speaker 1: But I guess my question is why do even need
44:33
Speaker 1: to go that far? Like, couldn't I just use the
44:34
Speaker 1: gyroscope here on Earth and then measure the galaxies relative
44:38
Speaker 1: to my little gyroscope. Yeah, but the Milky Way is
44:40
Speaker 1: a better gyroscope than your little gyroscope. The Milky Way
44:43
Speaker 1: and the Solar System provide pretty nice gyroscope because it's
44:46
Speaker 1: a huge amount of mass and a very long lever arm,
44:49
Speaker 1: and so they're very precise. But there are lots of
44:51
Speaker 1: ways you can construct this experiment. The real limitation, though,
44:54
Speaker 1: is that it's very hard to observe the motion of
44:57
Speaker 1: those distant galaxies because they're really really far away, and
45:01
Speaker 1: so they hardly move at all. And we've only been
45:04
Speaker 1: looking at them for like a hundred years. It's only
45:06
Speaker 1: Hubble a hundred years ago they even discover that there
45:08
Speaker 1: were other galaxies out there. So if they are moving,
45:11
Speaker 1: they're moving very very slow, not in a way that
45:14
Speaker 1: we can tell relative to spacetime, right, They're moving super slow.
45:20
Speaker 1: They're moving they're expanding, right, they're moving away from us.
45:22
Speaker 1: But now we're talking about not radial motion away from us,
45:25
Speaker 1: the rotational motion right perpendicular to the line between us
45:29
Speaker 1: and them, and we haven't seen that kind of rotation.
45:32
Speaker 1: Like I think you're saying, like, if you correct for
45:34
Speaker 1: the motion of the Earth and correct for the motion
45:36
Speaker 1: of the Earth around the Solar System and the milk
45:38
Speaker 1: away and all that, it would be hard to tell
45:40
Speaker 1: because they're so far away, Like for us to see
45:43
Speaker 1: them spinning around and around the cosmos, it would have
45:46
Speaker 1: to be moving like ridiculously fast, right, Because we can
45:49
Speaker 1: measure their velocity in a radial direction pretty well because
45:53
Speaker 1: of Doppler effect. Measuring their velocity in the other direction,
45:56
Speaker 1: you know, requires seeing their change in their own relative
46:00
Speaker 1: to the Milky Way, which requires like you know, seeing
46:02
Speaker 1: them actually move, and that's really hard to do for
46:05
Speaker 1: stars and even harder to do for galaxies. They need
46:07
Speaker 1: to be either moving really really fast, or you have
46:09
Speaker 1: to observe for like a billion years and we're only
46:11
Speaker 1: a hundred years in. Yeah, that's the real limitation. Like
46:14
Speaker 1: it's possible, and you just need a lot of time,
46:16
Speaker 1: or they need to be moving really really fast in
46:17
Speaker 1: an obvious way that we can see it, and that's
46:20
Speaker 1: not happening. Can you just to ask him? Call him
46:24
Speaker 1: all right? So that that one has its limitations. You're
46:26
Speaker 1: not gonna gonna get a Nobel prize anytime soon with
46:29
Speaker 1: that method. What are some other ways we can measure?
46:31
Speaker 1: Other things we can do is to look at the
46:33
Speaker 1: expansion of the universe. So we know that things that
46:37
Speaker 1: are far away from us are moving away from us,
46:39
Speaker 1: and we know that that expansion is accelerating. So this
46:42
Speaker 1: is the discovery of dark energy. That something is stretching out.
46:45
Speaker 1: The universe seems to be creating new space between points
46:48
Speaker 1: all of the time. And the interesting thing is that
46:51
Speaker 1: cosmologists say that if the whole universe was rotating, if
46:54
Speaker 1: everything was spinning, then that would look a little different.
46:57
Speaker 1: That expansion would look different than it would if the
47:00
Speaker 1: universe was not spinning. And so the way that we
47:03
Speaker 1: measure that the universe is expanding is a couple of ways.
47:06
Speaker 1: One is that we look at type one A supernova,
47:08
Speaker 1: these standard candles that we know exactly how bright they
47:11
Speaker 1: should be, and so when we see one, we can
47:13
Speaker 1: tell how far away it is because of how bright
47:16
Speaker 1: we see it. We have these like tracer points in
47:18
Speaker 1: the universe, so we can see their expansion over time,
47:21
Speaker 1: and we can see the history of the expansion of
47:23
Speaker 1: the universe. And if there was a swirl in that expansion,
47:27
Speaker 1: if the universe was rotating at the same time as expanding,
47:30
Speaker 1: then that would look a little different than if it
47:32
Speaker 1: was just expanding in a purely radial way. What do
47:35
Speaker 1: you mean, because I would mess with the I guess
47:37
Speaker 1: the basic motion of things, right, because it suddenly has
47:41
Speaker 1: an extra component of velocity and it's feeling an extra
47:44
Speaker 1: component of exploration. Yeah. Imagine you're like on a Merry
47:47
Speaker 1: Go Round and you have a bunch of friends and
47:49
Speaker 1: you all throw ping pong balls out. If you're spinning,
47:53
Speaker 1: or if you're not spinning, then those ping pong balls
47:55
Speaker 1: have a different path, right, They would curve if you're spinning.
47:58
Speaker 1: That's one way to measure or rotation. And so we're
48:01
Speaker 1: trying to measure the rotation of all the stuff in
48:03
Speaker 1: the universe by looking at the path of these tracers,
48:06
Speaker 1: these type one a supernova to see is it consistent
48:08
Speaker 1: which is flying straight out or is it consistent with curving.
48:12
Speaker 1: We can't observe them for very long. But we have
48:14
Speaker 1: these momentary tracers, then you can do some sort of
48:17
Speaker 1: like back calculation to say, like are they consistent with
48:20
Speaker 1: rotation or are they consistent with pure expansion? Oh? I see.
48:23
Speaker 1: I think what you're saying is like, like if everything
48:25
Speaker 1: in the universe was in a Merry Go round, we
48:27
Speaker 1: would see the stars, the supernova or at least the
48:30
Speaker 1: stuff around like the equator. That stuff would be maybe
48:33
Speaker 1: expanding faster, maybe or moving differently than the stuff like
48:37
Speaker 1: above and below us on the Merry Go round. Yeah,
48:40
Speaker 1: if there's an overall rotation, that implies that there's a
48:42
Speaker 1: rotation in some plane, right, some access around which you
48:46
Speaker 1: are rotating, and that essentially defines a north and a
48:49
Speaker 1: south just the same way like the Earth's rotation defines
48:52
Speaker 1: a north pole and a south pole, and the Solar
48:54
Speaker 1: system has a north and the south defined by its rotation.
48:57
Speaker 1: So that would create different directions in the sky where
49:00
Speaker 1: things look different, basically a huge anisotropy. We actually talked
49:04
Speaker 1: about on the podcast once about this access of evil,
49:06
Speaker 1: this idea that maybe things in the universe do look
49:09
Speaker 1: a little bit different north to south if depending on
49:12
Speaker 1: how you define it. That's exactly the kind of thing
49:14
Speaker 1: you would expect to see if the universe was rotating.
49:16
Speaker 1: You'd expect to see some difference in one half of
49:19
Speaker 1: the sky versus the other half of the sky. Right,
49:21
Speaker 1: you would expect it to be a little wider in
49:23
Speaker 1: the middle around the waistline. The universe is either rotating
49:27
Speaker 1: or been eating too much chocolate, you know, one of
49:29
Speaker 1: those two. There's only two posibilities. You can use similar
49:32
Speaker 1: tests with another very sensitive probe of the universe's expansion.
49:36
Speaker 1: That's the cosmic microwave background radiation. That's this light from
49:39
Speaker 1: the very very early universe. And we were talking about
49:42
Speaker 1: how if this rotation exists, it should have existed a
49:45
Speaker 1: long time ago. It's actually much more powerful to see
49:47
Speaker 1: it earlier on, before the universe expanded so much, because
49:51
Speaker 1: the rotation would be more dramatic and so in the
49:53
Speaker 1: same way that if the universe is rotating, it would
49:56
Speaker 1: affect the way things are expanding, it would also affect
49:58
Speaker 1: that plasma that generates did that CNB light The plasma
50:02
Speaker 1: is very sensitive to like how much dark matter there
50:04
Speaker 1: is and how it's moving, and how the normal matter
50:07
Speaker 1: is sloshing around into and out of those dark matter
50:10
Speaker 1: gravitational wells, and if there was an overall spin, it
50:13
Speaker 1: would affect those patterns in very subtle ways, and people
50:16
Speaker 1: have studied those and not seeing any evidence for universal rotation.
50:21
Speaker 1: M M. It's kind of like you we talked about
50:23
Speaker 1: it before, how the cosmic microwave background is like a
50:25
Speaker 1: picture of the baby universe, like an early picture of
50:29
Speaker 1: the universe, and so you you don't see any Basically,
50:32
Speaker 1: what you're saying is you don't see any spin in
50:34
Speaker 1: that picture, nor do you see it being uh, like
50:38
Speaker 1: the baby's not extra wide around the middle. Yeah, And
50:40
Speaker 1: it's a little subtle because it's not like you're looking
50:43
Speaker 1: at the actual universe and seeing it's spin. You're looking
50:46
Speaker 1: at like the patterns that spin would cause in the
50:49
Speaker 1: clumpiness of the universe. It would make very distinctive patterns.
50:53
Speaker 1: And this is actually the most sensitive test we have
50:56
Speaker 1: for the universe's rotation, is this cosmic microwave background light.
51:00
Speaker 1: In their early eighties, people saw some weird stuff in
51:02
Speaker 1: the sky from radio signals that led them to believe
51:05
Speaker 1: maybe the universe was rotating. There's a paper in two
51:08
Speaker 1: I read from a guy in Manchester in Birch who
51:11
Speaker 1: claimed to be measuring the rotation of the universe that
51:14
Speaker 1: attended the minus thirteen radiants per year. But this measurement
51:18
Speaker 1: in the CNB is more powerful and is not consistent
51:21
Speaker 1: with any rotation, So people think Burchess measurement was probably wrong. Well,
51:24
Speaker 1: I'm getting this sort of the picture that if you're
51:26
Speaker 1: asking the question, is the stuff in the universe spinning?
51:30
Speaker 1: If it was spinning, then you would see some sort
51:33
Speaker 1: of like you said, an isotriptropy, meaning like it would
51:36
Speaker 1: the universe would look differently whether you're looking at the
51:39
Speaker 1: spinning direction or whether you're looking at the its waistline
51:42
Speaker 1: or the equator of the spinning stuff in the universe.
51:45
Speaker 1: And it seems like for for all accounts looking at
51:48
Speaker 1: galaxies and looking at the baby picture of the universe,
51:51
Speaker 1: there is no different or like preferred direction that you
51:54
Speaker 1: can see as far as we can tell. Here's a
51:56
Speaker 1: study we talked about on the Access of Evil episode
51:58
Speaker 1: where people looked at the spin of Alexis and they
52:00
Speaker 1: found that galaxies in one direction of sky tend to
52:03
Speaker 1: be spinning left more than any other direction of the sky.
52:06
Speaker 1: And they claim this is maybe evidence for the universe
52:08
Speaker 1: to be rotating. But a lot of people criticize that
52:11
Speaker 1: paper and think that it probably underestimates systematic effects that
52:14
Speaker 1: could cause that, you know, local gravitational effects or or
52:17
Speaker 1: other uncertainties that they didn't take into account. So overall,
52:20
Speaker 1: there's no evidence for universal rotation, although our cosmology allows it. Right,
52:25
Speaker 1: it is possible our universe to rotate, it just doesn't
52:28
Speaker 1: seem to be doing that right, or at least not
52:31
Speaker 1: to tend to the negative nine radiance per year, which
52:35
Speaker 1: sounds like a small number. It's like point zero zero
52:37
Speaker 1: zero zero nine zeros and then a one. But if you,
52:41
Speaker 1: like you said before, like you know, the universe expanded
52:43
Speaker 1: tend to the what like thirties sixty two times since
52:48
Speaker 1: the Big Bang, And so it could just be that
52:51
Speaker 1: are these instruments this way of knowing, it's not accurate
52:54
Speaker 1: enough yet, Like there could be a little bit of
52:56
Speaker 1: spin down there still underneath the what we can measure.
52:59
Speaker 1: You will never have infinite precision, and so either the
53:02
Speaker 1: universe is not spinning or spinning very very gently. Yeah,
53:05
Speaker 1: it's a kitty merry go around. You know, nobody wants
53:09
Speaker 1: us to throw up all that chocolate. Yeah, nobody wants
53:13
Speaker 1: the six flags crazy roller coaster eversion of the universe.
53:17
Speaker 1: So I guess the answer is, is the stuff in
53:20
Speaker 1: the universe spinning? Not that we can tell, but it
53:22
Speaker 1: could still be spinning a little bit. We just don't
53:26
Speaker 1: know for sure yet. And fascinatingly, we could tell if
53:29
Speaker 1: the stuff in the universe was spinning. Spin itself is absolute,
53:33
Speaker 1: and that tells you something really deep about the nature
53:36
Speaker 1: of space and time and motion. That velocity is relative,
53:40
Speaker 1: but acceleration is not. Acceleration is absolute relative to space
53:44
Speaker 1: time itself. Yeah, and it would also sort of tell
53:47
Speaker 1: you that the universe kind of has a direction, right,
53:50
Speaker 1: It kind of would have a north and a south,
53:52
Speaker 1: and a tropical zone. It prefers dark chocolate to white chocolate.
53:56
Speaker 1: All right, Well, um, we hope your head is not
53:59
Speaker 1: spinning from all that discussion about spinning. Well, we hope
54:02
Speaker 1: that it does sort of make you think about whether
54:04
Speaker 1: or not the things around you are moving the way
54:06
Speaker 1: you think they are, and whether or not the universe
54:09
Speaker 1: was maybe born a pretty chill baby or a crazy
54:12
Speaker 1: spinning baby. And I hope you come away a little
54:14
Speaker 1: bit in awe of the fact that we can ask
54:17
Speaker 1: such amazing enormous questions about the nature of the cosmos,
54:21
Speaker 1: and that we have ways just from this tiny spinning
54:24
Speaker 1: rock finding initial answers to these questions. Yeah, and that
54:28
Speaker 1: we can talk about it in an hour and only
54:31
Speaker 1: make forty seven chocolate references. That's right, only make the
54:35
Speaker 1: forty seven bad chocolate plants. All right, Well, we hope
54:39
Speaker 1: you enjoyed that. Thanks for joining us, see you next time.
54:50
Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain
54:53
Speaker 1: the Universe is a production of I heart Radio. For
54:56
Speaker 1: more podcast from my heart Radio, visit the i heart
54:59
Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your
55:02
Speaker 1: favorite shows. H