Latest / Daniel and Kelly’s Extraordinary Universe / Listener Questions 53: Strong force, primordial atoms and infinities

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Listener Questions 53: Strong force, primordial atoms and infinities · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Daniel, how long have we been doing this podcast?
0:10
Speaker 2: Now?
0:10
Speaker 3: Oh? Man, I'm not sure. Kind of feels like forever.
0:14
Speaker 1: Do you think we could go on forever?
0:15
Speaker 3: I don't know. I don't think we're going to run
0:17
Speaker 3: out of topics.
0:18
Speaker 1: You think there's an infinite number of questions we can
0:22
Speaker 1: talk about in physics.
0:23
Speaker 3: I think you could just keep asking why forever? Yeah?
0:26
Speaker 1: Why do you think that is?
0:28
Speaker 3: I think you just proved my point.
0:29
Speaker 1: Wait, what do you mean why? Q ed you pretended
0:35
Speaker 1: to say just because I said so ardude.
0:37
Speaker 3: Because the universe says so. Universe is the ultimate?
0:41
Speaker 2: Dad or Mom?
0:57
Speaker 1: Hi, I'm orham Mack, cartoonists and the author of Oliver's Universe.
1:01
Speaker 3: Hi, I'm Daniel. I'm a particle physicist, a professor at
1:04
Speaker 3: UC Irvine, and I think I'll always be asking why, why?
1:07
Speaker 4: What?
1:09
Speaker 3: Why this universe and not some other universe. Imagine some
1:13
Speaker 3: moment in the deep future when we see the final
1:16
Speaker 3: theory of the universe that describes the most fundamental basic bits.
1:20
Speaker 3: I think people are still going to look at that
1:22
Speaker 3: idea and wonder, why does it work this way? Why
1:24
Speaker 3: couldn't it have been different?
1:27
Speaker 1: What if you get to the end Daniel, and you
1:29
Speaker 1: figure it everything out, and the answer is just because.
1:35
Speaker 3: Is that really an answer?
1:36
Speaker 1: Though it is, I give it to my children all
1:39
Speaker 1: the time.
1:40
Speaker 3: I don't know if that's an answer or a cop out.
1:42
Speaker 3: It kind of means like there is no answer, you know.
1:45
Speaker 3: One version of the answer is, Look, the universe could
1:47
Speaker 3: have been lots of different ways. It just is this way,
1:50
Speaker 3: which means there's fundamental randomness, not just in the operation
1:53
Speaker 3: of the universe, but in the very laws that government.
1:56
Speaker 5: Right.
1:57
Speaker 1: But it's still an answer that wouldn't be satisfying. Ye,
2:00
Speaker 1: going to sleep soundly that night, and just one night
2:03
Speaker 1: after that, you'll be totally fine. I see how deed
2:06
Speaker 1: your physics roots go.
2:08
Speaker 3: I'll have one long dark night of the physics soul.
2:11
Speaker 1: Yeah, and then you're over it. Yeah, that's fine.
2:15
Speaker 3: You've got to embrace stuff and move on. You know,
2:17
Speaker 3: no point in holding grudges against the universe.
2:20
Speaker 1: Well, speaking of moving on, Welcome to our podcast, Daniel
2:22
Speaker 1: and Jorge Explain the Universe, a production of iHeartRadio.
2:26
Speaker 3: In which we refuse to move on until we understand
2:29
Speaker 3: something and explain it in an understandable way to you.
2:32
Speaker 3: We think, we hope we pray that the universe is understandable,
2:36
Speaker 3: is explainable, is digestible by our petty little human minds,
2:40
Speaker 3: and we do our best to bring you up to
2:42
Speaker 3: the forefront of human knowledge and the abyss of human ignorance.
2:45
Speaker 1: That's right, because there is still a lot that we
2:47
Speaker 1: don't know about the universe, a lot to discover, a
2:49
Speaker 1: lot to find out, a lot to explore. In fact,
2:52
Speaker 1: maybe we should rename this podcast Daniel and Jorge wonder why,
2:56
Speaker 1: although is that taken? Is that taken?
2:58
Speaker 3: It's a great name for a show, and somebody should
3:00
Speaker 3: really do that.
3:01
Speaker 1: Yeah, somebody should make a yeah TV show maybe for kids.
3:04
Speaker 3: Yeah, exactly, Yeah, replace our names with some kids name
3:07
Speaker 3: or something. I don't know, we'll figure it out.
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Speaker 1: Yeah, an awesome girl's name. Perfect. I'm sure they'll give
3:12
Speaker 1: us a show, even though we've never made one before.
3:16
Speaker 3: Now you're just being ridiculous.
3:18
Speaker 1: Yeah, who would do that?
3:19
Speaker 3: There are a lot of amazing mysteries in the universe
3:22
Speaker 3: things to wonder about, not just whether two total nubes
3:25
Speaker 3: can make a TV show on PBS, but questions about
3:28
Speaker 3: the nature of the universe, how it works, why it
3:31
Speaker 3: works this way not some other way. Unfortunately, we have
3:33
Speaker 3: not yet run out of those questions.
3:35
Speaker 1: Yeah, it seems that human curiosity is sort of endless,
3:38
Speaker 1: and we have evidence of that from all the questions
3:40
Speaker 1: that the podcast receives from listeners.
3:43
Speaker 3: Because the process of doing science is tapping into those
3:46
Speaker 3: human questions to wonder, why is it this way not
3:48
Speaker 3: some other way? How does this idea fit with that
3:51
Speaker 3: other idea? Can I click them both together in my head?
3:53
Speaker 3: When they don't quite fit? That's an opportunity to learn something,
3:56
Speaker 3: maybe to reveal something about the universe. That's how science
4:00
Speaker 3: moves forward. People asking questions, and those people are podcasters, scientists,
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Speaker 3: television show producers, and everybody else who wants to understand
4:08
Speaker 3: the universe.
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Speaker 1: Yeah, we get lots of questions, and sometimes we actually
4:12
Speaker 1: answer those questions here on the podcast, questions that we
4:15
Speaker 1: feel everyone would enjoy thinking about and finding out what
4:19
Speaker 1: the current answer and science is.
4:21
Speaker 3: That's right. But even if your question doesn't make it
4:23
Speaker 3: to the podcast, you will still get an answer. I
4:26
Speaker 3: will write back to you and try to help you understand.
4:28
Speaker 3: So please, everybody, don't be shy write to us to
4:31
Speaker 3: questions at Daniel and Jorge dot com. We really will
4:35
Speaker 3: right back.
4:36
Speaker 1: So to the end the podcast, we'll be tackling listener
4:43
Speaker 1: questions Number fifty three Daniel Hoffen. Do we do these now?
4:47
Speaker 1: About every month we answer listener questions.
4:49
Speaker 3: We used to do it about every month, but we've
4:50
Speaker 3: been getting a lot more questions recently, so I've uped
4:53
Speaker 3: it to almost every week to try to catch up.
4:55
Speaker 1: Wow, what do you think is causing this increase in questions?
5:00
Speaker 3: Good question, I'll add it to the list.
5:02
Speaker 1: We'll spend an episode talking about why we get more
5:04
Speaker 1: questions in the episode, and then we'll implode. We'll implode
5:08
Speaker 1: from the paradoxical nature of this.
5:10
Speaker 3: The infinite recursion in that question will generate information density
5:13
Speaker 3: that creates a black hole podcast.
5:15
Speaker 1: Yeah, and then we'll be able to go on forever.
5:19
Speaker 3: That's called the singularity.
5:20
Speaker 1: Because then the next episode will be yes, how are
5:23
Speaker 1: we doing a podcast while we're getting questions?
5:26
Speaker 3: I can just see it alien anthropologists in the future
5:29
Speaker 3: trying to figure out how human civilization ended in a
5:32
Speaker 3: podcast singularity.
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Speaker 1: Well, hopefully we're not the end of civilization, but maybe
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Speaker 1: the beginning of a lot of people's questioning about the universe.
5:39
Speaker 1: And so we have three awesome questions here today that
5:41
Speaker 1: we're going to try to answer or at least talk
5:43
Speaker 1: about great questions about the strong force, about the creation
5:47
Speaker 1: of matter, and about the infinity of time. Hopefully this
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Speaker 1: podcast will not be an infinite length of time, but
5:56
Speaker 1: we hope your love for it is infinite no matter
5:58
Speaker 1: what kind of matter we talked about.
6:01
Speaker 3: I hope anti matter doesn't lead the anti love.
6:03
Speaker 1: Yeah, that would be a strong statement. All right, let's
6:06
Speaker 1: dig into our first question, and this one is from Emily.
6:09
Speaker 3: We actually have two questions here from Emily and from
6:13
Speaker 3: Sarah that asked related questions. I thought we could answer
6:15
Speaker 3: all together a double question.
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Speaker 4: All right, Hi, Daniel and Joje. Here's Emily and I
6:21
Speaker 4: have a few questions about the strong force. First, how
6:26
Speaker 4: does the strong force even really work? And how can
6:31
Speaker 4: it be that it gets stronger with the distance? Does
6:36
Speaker 4: that ever end? As in, is there a maximum strength
6:39
Speaker 4: to the strong force? Because it cannot get infinitely strong?
6:45
Speaker 3: Right?
6:46
Speaker 4: If it did, we could never break apart of proton,
6:51
Speaker 4: could we? And one more question, If I had the
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Speaker 4: strength to pull two quarks.
6:58
Speaker 6: Away from each other, would I at some point need
7:02
Speaker 6: infinite strength to keep pulling? Thanks for answering my question.
7:08
Speaker 6: I really like your podcast. Keep up the great work.
7:12
Speaker 7: Hi.
7:13
Speaker 8: I want to ask about the strong force. What is
7:16
Speaker 8: the strong force? What does it do? Why is it
7:20
Speaker 8: so strong? Why is it so difficult to understand and calculate?
7:27
Speaker 8: And why is it range considered shorter than electromagnetisms.
7:34
Speaker 1: All right, some pretty strong questions here, Daniel. Do you
7:37
Speaker 1: think we're strong enough to answer it?
7:39
Speaker 3: I hope. So the strong force is tricky. It is
7:42
Speaker 3: complicated stuff, and these are great questions trying to get
7:45
Speaker 3: intuitive understanding of how it all works.
7:48
Speaker 1: I like how she phrased the question Emily here, how
7:51
Speaker 1: does that even work?
7:54
Speaker 3: How does it all even work? Can we just describe it?
7:57
Speaker 3: How can we actually explain it?
7:59
Speaker 1: All? Right? Well, we had two questions that we'll tackle
8:01
Speaker 1: one at a time. Daniel, How does the strong force work?
8:05
Speaker 1: And why does it get stronger with distance?
8:07
Speaker 4: So?
8:08
Speaker 3: The strong force is a force between any particles that
8:11
Speaker 3: have color charge. Color charges is like a version of
8:14
Speaker 3: electric charge. You know how electrons have negative charge and
8:17
Speaker 3: protons have positive charge, and that's how you know they
8:20
Speaker 3: attract each other or to electrons will repel each other.
8:24
Speaker 3: In a strong force, we have a different kind of
8:26
Speaker 3: charge we call it color, and any particles that have
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Speaker 3: these color we say feel the strong force. This is
8:32
Speaker 3: just kind of descriptive the way we gave labels too
8:35
Speaker 3: particles to describe their charge, to explain the forces we
8:38
Speaker 3: see pulling and pushing between them. We give these colored
8:41
Speaker 3: labels to quarks to describe the forces that we describe
8:45
Speaker 3: between them.
8:46
Speaker 1: Well, maybe taking a step back, the strong force is
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Speaker 1: one of the four fundamental forces that businesses have noticed
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Speaker 1: about the universe, and these are the forces that pull
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Speaker 1: and push matter together or apart.
8:57
Speaker 3: That's right. It depends a little bit how you count
8:59
Speaker 3: the forces. Some people say two, some people say three,
9:02
Speaker 3: some people say four. And the four force version you
9:05
Speaker 3: have gravity, which is not really a force, and then
9:08
Speaker 3: you have electricity and magnetism as one force, the third force,
9:11
Speaker 3: and then the strong forces the fourth and the more
9:14
Speaker 3: simplified version, we say gravity is not a force, you
9:17
Speaker 3: don't count it. Electricity and magnetism have been combined with
9:20
Speaker 3: the weak force into the electro weak force, and then
9:24
Speaker 3: the second force is the strong force. So in the
9:26
Speaker 3: sort of unified version, you really only have two forces,
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Speaker 3: electroweak and the strong force.
9:31
Speaker 1: And so the strong force is the one that pushes
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Speaker 1: and pulls quarks, right.
9:36
Speaker 3: Yeah, that's right. Anything with a color charge, which means
9:38
Speaker 3: quarks and also gluons, electrons and muons, and those particles
9:42
Speaker 3: don't have a color charge, so they just don't feel
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Speaker 3: a strong force the way a neutral particle doesn't feel
9:47
Speaker 3: an electric field.
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Speaker 1: Okay, and so part of the Emily's question is how
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Speaker 1: does it get stronger with distance? So does it get
9:54
Speaker 1: stronger with distance? Meaning if you pull the quarts apart,
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Speaker 1: they're actually going to be pulling the dwarf each other
10:00
Speaker 1: or apart more.
10:02
Speaker 3: Yeah, it's really weird and very counterintuitive with gravity and
10:05
Speaker 3: with electromagnetism. If it's attracting two particles and you try
10:09
Speaker 3: to pull them apart, it gets easier as you get
10:11
Speaker 3: further apart. Imagine a proton an electron and you're holding
10:14
Speaker 3: onto them with tweezers and you're pulling them apart. As
10:17
Speaker 3: you succeed in pulling them further and further apart, the
10:19
Speaker 3: force on them gets weaker and it gets easier and easier.
10:22
Speaker 3: But with a strong force, we notice something different. We
10:25
Speaker 3: notice that after a certain distance, the force stays constant,
10:29
Speaker 3: doesn't actually grow with distance. It stays constant. So after
10:32
Speaker 3: about like the width of a proton, if you pull
10:35
Speaker 3: two quarks apart, the force on them is the same
10:38
Speaker 3: no matter how far apart you pull them.
10:39
Speaker 1: Wait, what so it doesn't get stronger with distance only
10:43
Speaker 1: for a little bit.
10:43
Speaker 3: It decreases with distance until you get about a proton's
10:46
Speaker 3: width apart, and then it stays constant. It doesn't fall
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Speaker 3: off like one of our are square, the way electromagnetism does.
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Speaker 1: Oh so the strong word doesn't get stronger with distance.
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Speaker 3: Doesn't get stronger with distance in the sense that the
10:59
Speaker 3: force doesn't increase, but the amount of energy stored in
11:02
Speaker 3: that bond does because forces like the slope of the energy,
11:06
Speaker 3: and so the energy is actually just growing and growing
11:08
Speaker 3: as those two quarks pull apart.
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Speaker 1: But the ford doesn't get stronger, right, doesn't get stronger.
11:14
Speaker 1: There's just more potential the more you pull them apart.
11:16
Speaker 1: You just like maybe you have more gravitational potential the
11:19
Speaker 1: higher you go up a ladder.
11:21
Speaker 3: Yeah, exactly, And this feels weird compared to like electromagnetism,
11:24
Speaker 3: but it's not so unintuitive.
11:26
Speaker 4: You know.
11:26
Speaker 3: You take a rubber band, for example, and you pull
11:28
Speaker 3: on it. The force doesn't drop as the rubber band
11:30
Speaker 3: gets stretchier and stretchier. Right, So there are some kinds
11:33
Speaker 3: of analogies we have in the everyday world. But Emily's
11:37
Speaker 3: probably wondering, like, why does this happen? How does it
11:39
Speaker 3: work this way? And that's not something we really understand.
11:42
Speaker 3: This is just our description of what we see happen
11:44
Speaker 3: between particles.
11:46
Speaker 1: Part of our question is is there a maximum to
11:49
Speaker 1: the strong for it? I guess she was imagining that
11:51
Speaker 1: the strong force was like a rubber band. The more
11:54
Speaker 1: you pull it apart, the stronger it gets. And so
11:56
Speaker 1: she's wondering, is there a maximum to this force? Can
11:58
Speaker 1: it just be infinite if you pull the two things
12:01
Speaker 1: apart infinitely? But it sounds like you're saying that this
12:05
Speaker 1: wouldn't really happen.
12:06
Speaker 3: It wouldn't really happen because the energy can't grow to infinity. Like,
12:09
Speaker 3: as you pull these things apart, the four states constant,
12:12
Speaker 3: but the energy stored in that bond just grows and
12:14
Speaker 3: grows and grows and grows. But at some point there's
12:17
Speaker 3: so much energy in that bond that the universe prefers
12:20
Speaker 3: to transfer that energy into mass, to convert that energy
12:23
Speaker 3: into quarks because quarks are actually pretty light. They don't
12:26
Speaker 3: take a lot of energy to make. So the universe,
12:29
Speaker 3: which prefers to spread energy out rather than have it
12:31
Speaker 3: concentrated in one bond or in one state, will prefer
12:35
Speaker 3: to create a bunch of quarks out of that energy.
12:37
Speaker 3: So you have these two quarks that you're pulling apart.
12:39
Speaker 3: The universe prefers to create more quarks to shorten the
12:42
Speaker 3: distances between quarks, spending that energy to create the mass
12:46
Speaker 3: and reducing the energy of the bonds.
12:48
Speaker 1: Well, what so I take two quarks they're held together
12:52
Speaker 1: by the strong force, I pull them apart, and at
12:55
Speaker 1: some point, like what kind of distance that we're talking about,
12:57
Speaker 1: like a meter.
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Speaker 3: We're talking about like the width of a proton.
13:00
Speaker 1: Oh okay, so a little smaller you pull them apart
13:04
Speaker 1: the width of a proton, and then what like new
13:06
Speaker 1: quarks pop up in the middle. You'd have to pop
13:09
Speaker 1: up two new ones, right, One of the two new
13:11
Speaker 1: ones is going to be attached to one of my
13:13
Speaker 1: original protons, and the other new one is going to
13:15
Speaker 1: be attached to the second of my original quarks.
13:18
Speaker 3: Yeah, exactly, And we do this all the time at
13:20
Speaker 3: the Large Hadron Collider we create a quark and antiquark
13:23
Speaker 3: pair with a lot of energy, so they're flying apart
13:25
Speaker 3: super duper fast, almost at the speed of light, and
13:28
Speaker 3: very quickly. What happens between them is you create another
13:30
Speaker 3: quark antiquark pair. So instead of having a quark anti
13:34
Speaker 3: quark a certain distance apart, now both of those have
13:36
Speaker 3: a new partner to be bound with at half the distance,
13:41
Speaker 3: and then those start to fly apart and that band snaps.
13:44
Speaker 3: So you get this whole shower of quarks and anti
13:46
Speaker 3: quarks being created. All that energy is converted into a
13:49
Speaker 3: whole stream of new particles, and they like to stay
13:52
Speaker 3: close together to minimize the energy stored in those bonds.
13:55
Speaker 2: Hmmm.
13:56
Speaker 1: Interesting, all right, so then you couldn't get to infinity
14:00
Speaker 1: at some point. It's like the rubberband breaks, yeah kind of, yeah, exactly.
14:03
Speaker 3: It's like the rubber band prefers to snap rather than
14:05
Speaker 3: to stretch out to infinity. And so in principle, you
14:09
Speaker 3: could have a universe where two quarks are infinitely far apart,
14:13
Speaker 3: holding infinite energy, but in practice the universe prefers to
14:16
Speaker 3: spread that energy out. It's basically just entropy that very
14:18
Speaker 3: unlikely to happen. The universe prefers configurations with more probability,
14:23
Speaker 3: which means the energy is more spread out, and so
14:25
Speaker 3: it replaced that infinite energy bond with a lower energy
14:28
Speaker 3: bond and a bunch of quarks.
14:31
Speaker 1: So I guess the strong force is not that strong.
14:34
Speaker 1: It snaps at some point.
14:36
Speaker 3: It's so strong and energetic that it usually breaks down.
14:39
Speaker 1: Yeah, all right, then, now Sarah's question our second question
14:43
Speaker 1: of this question. See you're the one introducing recursion here.
14:46
Speaker 1: We have two questions inside of one question. Sarah's question
14:50
Speaker 1: is why is the strong for so strong? Now? Is
14:53
Speaker 1: there actually an answer to that?
14:54
Speaker 3: There's not a great answer to that. There's a terrible
14:56
Speaker 3: answer and a less terrible answer. Totally terrible answer is
15:01
Speaker 3: this is just what we measure. We go out in
15:02
Speaker 3: the universe. We measure the force between particles. We can
15:05
Speaker 3: measure the strength of stuff. We can say, for example,
15:08
Speaker 3: gravity is much weaker than electromagnetism, because if you take
15:11
Speaker 3: two particles, you mostly feel electromagnetism between them rather than gravity.
15:15
Speaker 3: Gravity is so much weaker. In the same way, we
15:18
Speaker 3: can compare the strength of electromagnetism to the strong force
15:21
Speaker 3: and say, hey, between two quarks which have both kinds
15:24
Speaker 3: of charge, which force is dominating the interaction. So those
15:28
Speaker 3: are just measurements we make out in the universe, just
15:30
Speaker 3: numbers the way we measure like the speed of light
15:32
Speaker 3: or planks constant. These are just things we see in
15:35
Speaker 3: the universe.
15:36
Speaker 1: So basically, you're saying because you said so, because that's.
15:39
Speaker 3: What the universe is showing us. The slightly less terrible
15:43
Speaker 3: answer is that we think at an earlier moment in
15:45
Speaker 3: the universe, all the forces had the same strength. We
15:49
Speaker 3: talked about this recently on the podcast. A lot of
15:51
Speaker 3: these forces, their strength depends on energy, like how fast
15:56
Speaker 3: particles are going, how much energy they have, the forces
15:59
Speaker 3: get stronger or depending on the energy and the energy
16:02
Speaker 3: density of the universe varies with time, like it used
16:05
Speaker 3: to be hotter and more energy dense in the early universe.
16:08
Speaker 3: So we think in the early universe, if you sort
16:10
Speaker 3: of rewind the clock, a lot of these forces might
16:13
Speaker 3: have had the same strength. So it might be that
16:16
Speaker 3: very early in the universe the strong force and the
16:19
Speaker 3: electroweak force were both the same strength, and then something
16:22
Speaker 3: happened when the universe cooled, it like cracked in an
16:24
Speaker 3: asymmetric way to give one of them more strength and
16:28
Speaker 3: one of them less strength.
16:29
Speaker 1: WHOA, So there was like an option the universe had.
16:32
Speaker 1: Is that what you're saying, Like it could have been
16:34
Speaker 1: a different way, but somehow it broke that way, or
16:36
Speaker 1: it could it have only broken this way?
16:38
Speaker 3: Yeah, we don't understand that. This is something in physics
16:40
Speaker 3: we call spontaneous symmetry breaking, when the universe had a symmetry,
16:44
Speaker 3: a balance, and then it cracked as it cooled. A
16:47
Speaker 3: famous analogy for this is like you sit down at
16:49
Speaker 3: a dinner table and you have silverware to your left
16:51
Speaker 3: and silverware to your right. Which one do you pick? Well,
16:54
Speaker 3: if you pick to your left, then everybody's going to
16:55
Speaker 3: have to pick to their left. If you pick to
16:57
Speaker 3: your right, everybody's gonna have to pick to your right.
17:00
Speaker 3: And another example of this is the Higgs boson. As
17:02
Speaker 3: the universe cools, all the particles started out having no mass,
17:06
Speaker 3: but then the Higgs field gives mass to particles, but
17:08
Speaker 3: not in a symmetric way. It made like the W
17:11
Speaker 3: and the Z very massive and left the photon massless.
17:14
Speaker 3: This is called electroweak symmetry breaking. So as the universe
17:18
Speaker 3: cools and enters another phase, some of these symmetries crack
17:22
Speaker 3: in a way we don't fully understand.
17:24
Speaker 1: So then are you saying that at different universe where
17:27
Speaker 1: the strong force wasn't a strong that's a totally plausible,
17:30
Speaker 1: mathematically possible universe that we could have been living in.
17:33
Speaker 1: But somehow we're living in this universe where the strong
17:36
Speaker 1: force is strong.
17:37
Speaker 3: It might be that those universes are equally possible, or
17:40
Speaker 3: it might be that there's a reason that it cracked
17:42
Speaker 3: this way and not some other way. It's not something
17:44
Speaker 3: that we currently understand, so it's possible, But it might
17:47
Speaker 3: be that we discover that there is a reason why
17:50
Speaker 3: the strong force cracked this way and the weak forces
17:52
Speaker 3: cracked the other way. Are currently we don't know why
17:55
Speaker 3: it's so strong?
17:55
Speaker 1: Do you think it was random?
17:57
Speaker 3: There's so many different theories, some that control it, some
17:59
Speaker 3: that even random. The true description of the universe is
18:02
Speaker 3: probably something we haven't even thought of yet, so it's
18:05
Speaker 3: still a deep question.
18:07
Speaker 1: I think the real question is if the strong force
18:09
Speaker 1: hadn't been so strong, would you just still have called
18:12
Speaker 1: it the strong force?
18:14
Speaker 3: We probably would have named it terribly. That's for sure.
18:17
Speaker 1: It could have been strong force.
18:20
Speaker 3: We have a pretty weak game in naming things. That's
18:23
Speaker 3: what's constantly across the multiverse. It a strong bias here
18:27
Speaker 3: because the strong force is so strong, it makes it
18:29
Speaker 3: really difficult to use. To another part of Sarah's question,
18:32
Speaker 3: why is it so difficult to do these calculations? And
18:35
Speaker 3: the reason is its strength. It's hard to do calculations
18:39
Speaker 3: with a force that likes to pop off all the time.
18:41
Speaker 3: It's crazy reactive because it makes it much more sensitive
18:44
Speaker 3: to getting the details wrong. Get a little detailed wrong,
18:47
Speaker 3: it propagates to a much bigger mistake. That's not true
18:50
Speaker 3: for the weak force, where mostly things just fade out anyway.
18:53
Speaker 3: So you make a little mistake, it's going to fade
18:55
Speaker 3: away and not affect your calculations. The strong force is
18:58
Speaker 3: like recursive, It builds on itself, and so little mistakes
19:01
Speaker 3: become bigger mistakes.
19:02
Speaker 1: M Terry volatile huh, yes, exactly. All right. Well, so
19:05
Speaker 1: then to answer Sarah's question, it's either because if we
19:08
Speaker 1: said so, or we don't know.
19:12
Speaker 3: Either there's no answer or there's an answer we haven't
19:14
Speaker 3: found yet.
19:15
Speaker 1: That basically covers every possibility because just because.
19:21
Speaker 3: Keep digging, Sarah, keep digging.
19:22
Speaker 1: All right, Well, thank you, Emily and Sarah for those
19:25
Speaker 1: great questions. Now let's dig into our second question, and
19:28
Speaker 1: this one is about the creation of matter, So let's
19:32
Speaker 1: dig into that. But first let's take a quick break.
19:47
Speaker 1: All right, we're answering listener questions here, and our second
19:50
Speaker 1: question comes from Trevor.
19:52
Speaker 5: Hey, guys, this is Trevor from Pittsburgh, Pennsylvania. I appreciate
19:55
Speaker 5: you taking my question. I've been thinking lately about the
19:58
Speaker 5: origin of the matter that we come across in everyday
20:01
Speaker 5: life that just makes us up and makes up all
20:04
Speaker 5: of our stuff, right, and how most of it probably
20:07
Speaker 5: came from stars that fuse hydrogen into heavier elements naturally.
20:13
Speaker 5: My presumption when I was thinking about this was that
20:15
Speaker 5: most of the particles that make all this stuff around
20:18
Speaker 5: us up probably spent some or possibly even most of
20:22
Speaker 5: their existence as parts of hydrogen atoms before those atoms
20:26
Speaker 5: were fused into heavier elements. But the more I think
20:29
Speaker 5: about it, the less confident I am in this presumption.
20:32
Speaker 5: Do we actually know anything about how much of the
20:35
Speaker 5: normal matter that exists today has at some point been
20:39
Speaker 5: a part of a hydrogen atom, And if there is
20:42
Speaker 5: matter that has never been a part of a hydrogen atom.
20:45
Speaker 5: Why not? And where is it? I think this whole
20:48
Speaker 5: line of questioning brings up yet another question. Does it
20:51
Speaker 5: even make sense to think of quantum particles as having
20:54
Speaker 5: a long history like this or are they more kind
20:57
Speaker 5: of ephemeral in nature. I really look forward to hearing
21:00
Speaker 5: what you guys have to say on this. Thanks again.
21:02
Speaker 1: Well, it seems like Trevor here is asking about the
21:06
Speaker 1: origin of matter, and the part I didn't understand is
21:09
Speaker 1: exactly whether it could have been part of the hydrogen atom.
21:11
Speaker 1: What does that mean?
21:11
Speaker 3: I think he's asking whether all the heavier bits of
21:14
Speaker 3: stuff that are out there, iron and lithium and uranium
21:18
Speaker 3: was once hydrogen. Like is it possible that uranium was
21:21
Speaker 3: just made from nothing? Or was every atom made from
21:25
Speaker 3: hydrogen atoms fused together? Is the history of every single
21:29
Speaker 3: atom that it was once hydrogen I see?
21:31
Speaker 1: Or do we have some like original atoms out there
21:34
Speaker 1: that were made heavy from the very beginning of the universe?
21:37
Speaker 6: Yeah?
21:38
Speaker 3: Exactly, Like is there any primordial uranium in the universe
21:41
Speaker 3: that was never hydrogen? Whereas hydrogen the only path to
21:45
Speaker 3: becoming an atom?
21:46
Speaker 1: Right, And we actually talked about this in our last recording.
21:48
Speaker 3: Did we Yeah, we talked about this in the Origin
21:51
Speaker 3: of Matter a few times. It's a really fascinating concept.
21:53
Speaker 3: It's incredible to me that we understand so much about
21:57
Speaker 3: the early universe that we can talk about how madam
21:59
Speaker 3: was and how it was fused, like down to the
22:02
Speaker 3: seconds and microseconds.
22:03
Speaker 1: Well, I guess maybe there's two questions here. Is one,
22:05
Speaker 1: can you make heavier matter instantly just from like the
22:09
Speaker 1: basic building blocks of the universe without going through the
22:12
Speaker 1: hydrogen atom? And the second question is what actually happened
22:16
Speaker 1: in the Big Bang? Did something like that happen or
22:19
Speaker 1: did all the matter in the universe go through hydrogen? First?
22:22
Speaker 3: Yeah, so let's trace the sort of early history of
22:24
Speaker 3: the universe to answer this question. You start out like,
22:27
Speaker 3: before there were any particles, you know, what was in
22:30
Speaker 3: the universe. Well, the furthest back we can go is
22:33
Speaker 3: to say there was some very hot dense state. We
22:36
Speaker 3: don't know where it came from, we don't know how
22:37
Speaker 3: it was made, we don't know what came before that.
22:40
Speaker 3: Just start with the assumption you have some hot dense state,
22:43
Speaker 3: and everything expands. That hot dense state becomes less hot
22:46
Speaker 3: and less dense, so it becomes colder and more dilute.
22:50
Speaker 3: So you have all this energy in these frothy quantum fields.
22:53
Speaker 3: As it cools down, you can start to talk about
22:55
Speaker 3: particles emerging from these fields the way like a room
22:58
Speaker 3: that's flooded is just filled with water, and then as
23:01
Speaker 3: you drain it, you end up with like droplets on
23:04
Speaker 3: the floor. So now the universe is sort of filled
23:06
Speaker 3: with the most fundamental particles quarks and electrons and stuff
23:09
Speaker 3: like that.
23:11
Speaker 1: Before it was just pure energy like this is before
23:14
Speaker 1: there were even quantum fields. Like the universe was so
23:17
Speaker 1: nuts so that you couldn't stand being there.
23:19
Speaker 3: We don't know what comes before fields. The nutso state
23:22
Speaker 3: of the universe is not something we can even describe.
23:24
Speaker 3: There's some vague theories about it, you know, inflotons decaying
23:27
Speaker 3: into quantum fields, but it's all very speculative. In question markye,
23:31
Speaker 3: the first moment we can describe is the universe filled
23:34
Speaker 3: with quantum fields. But those fields are so washed with
23:37
Speaker 3: energy that it doesn't make sense to talk about particles
23:39
Speaker 3: yet in those fields. It's only as those fields calm
23:43
Speaker 3: down and cool that it makes sense to talk about particles.
23:45
Speaker 3: As ripples in those fields, and.
23:47
Speaker 1: They calm down, cool because they were getting stretched.
23:50
Speaker 3: Out, right, Yeah, because as the universe expands, there's the
23:53
Speaker 3: same amount of matter in it, so that matter gets
23:55
Speaker 3: more dilute, right, and so you end up with particles
23:58
Speaker 3: rather than just huge piles of enery.
24:00
Speaker 6: Right.
24:00
Speaker 1: But those first particles are not atoms. They're the building
24:03
Speaker 1: blocks of atoms, meaning quarks. Right, So before you even
24:06
Speaker 1: had an atom, you had a whole bunch of quartz
24:08
Speaker 1: floating rep.
24:09
Speaker 3: Yeah, not just quarks. You have quarks, and you have gluons,
24:12
Speaker 3: you have photons, you probably have dark matter, you have electrons.
24:16
Speaker 3: You have all the sort of basic building blocks. And
24:18
Speaker 3: we don't know that these actually are the most basic
24:20
Speaker 3: building blocks. Just our current theory could be that quarks
24:23
Speaker 3: are made of something else, quigglyons, and the squiglyons were
24:26
Speaker 3: made first. But in our current description you end up
24:29
Speaker 3: with quarks and gluons and photons and dark matter. No
24:32
Speaker 3: atoms yet. Absolutely, it's still too hot for atoms to
24:35
Speaker 3: even form.
24:36
Speaker 1: Right, So we had the basic particles quarks, gluons, and
24:39
Speaker 1: then eventually those quarks fuse together to form protons and
24:43
Speaker 1: neutrons exactly.
24:44
Speaker 3: The strong force is pulling on all those quarks. There's
24:46
Speaker 3: a huge amount of energy. But then as things cool,
24:49
Speaker 3: the strong force pulls those quarks together to make protons
24:52
Speaker 3: and neutrons and other kind of bound states of quarks.
24:56
Speaker 3: Here's a strong force at play pulling those quarks together.
25:00
Speaker 3: Doublets of quarks like quark antiquark pair, we'll give you pions.
25:04
Speaker 3: Triplets of quarks will give you protons and neutrons. That's
25:07
Speaker 3: the moment when you go from like free particles to
25:10
Speaker 3: bound particles, when the universe gets cold enough to bind
25:13
Speaker 3: those quarks together.
25:14
Speaker 1: Right, right, Well, assuming that quarks and gluons and photons
25:17
Speaker 1: are fundamental particles, right, isn't it, there are still the
25:20
Speaker 1: possibility made they're made out of smaller particles.
25:23
Speaker 3: Yeah, exactly. If they're all made out of squiglyons, then
25:26
Speaker 3: first you start with the squigglyons, which then coalesce into
25:29
Speaker 3: the quarks and gluons, et cetera.
25:30
Speaker 1: Is that the official name squigglions?
25:33
Speaker 3: What's the macaltons, the wacinions? You know, who knows who
25:38
Speaker 3: knows ons?
25:39
Speaker 1: Just to be clear, that's not the official name, right,
25:41
Speaker 1: she made that up.
25:42
Speaker 3: I'm not aware of any theory of squig lyons. I
25:44
Speaker 3: just made that up. Yeah, did it sound official?
25:47
Speaker 1: If it's every thing, I think you should get credit
25:49
Speaker 1: for it.
25:50
Speaker 3: Oh yeah, you like that name, squiglyons. You think we
25:52
Speaker 3: should be teaching generations as students about it.
25:55
Speaker 1: I think it's as good as quarks and gluons.
25:59
Speaker 3: You know, there's a big fight about the name of quarks.
26:00
Speaker 3: There was one guy I wanted to call them quarks
26:02
Speaker 3: and somebody else wanted to call them aces and the
26:04
Speaker 3: quarksky one Mmmm. Yes, yes, I.
26:07
Speaker 1: Think we covered this in depth already, all the quarks
26:11
Speaker 1: of it.
26:11
Speaker 3: But that moment when quarks come together into protons and
26:15
Speaker 3: neutrons already have hydrogen. Essentially, the proton is a hydrogen nucleus,
26:19
Speaker 3: so physicists consider a proton.
26:21
Speaker 1: Hydrogen even though it doesn't have an electron to make
26:24
Speaker 1: it a whole atom.
26:25
Speaker 3: Yeah, we distinguish between the hydrogen ion just the proton,
26:29
Speaker 3: and the neutral hydrogen atom, which is a proton and electron.
26:33
Speaker 1: So wait, are you saying that a proton is an atom?
26:35
Speaker 1: So why do we even have the word proton?
26:38
Speaker 3: Why do we even have the word proton? Well, who's
26:40
Speaker 3: the one getting philosophical there?
26:41
Speaker 2: Man?
26:41
Speaker 3: Why don't we even think about protons. We use protons
26:45
Speaker 3: to count which atoms are which right, Helium has two,
26:47
Speaker 3: lithium has three, et cetera, et cetera. So it's definitely
26:51
Speaker 3: a thing in the universe we want to identify. But
26:53
Speaker 3: when you have only one of them, we consider that hydrogen.
26:56
Speaker 3: Even if you don't like that explanation, you think like,
26:58
Speaker 3: protons are not hydrogen yet, then those protons do something
27:01
Speaker 3: funky well before they find their electrons. In those first
27:05
Speaker 3: few moments, there is still enough energy for those protons
27:08
Speaker 3: to come together and make heavier elements like helium. So
27:12
Speaker 3: in the first few moments after the Big Bang, you
27:13
Speaker 3: make protons, you make neutrons, and then you also squeeze
27:16
Speaker 3: those protons together to make helium. So then the question
27:20
Speaker 3: is that helium did it once used to be hydrogen?
27:23
Speaker 3: That's essentially what Trevor is asking. If you made primordial
27:26
Speaker 3: helium right then during the Big Bang fusion, do you
27:29
Speaker 3: still count that as having been hydrogen? I say yes,
27:32
Speaker 3: because you didn't make the helium directly. You didn't make
27:35
Speaker 3: like a proton proton pair directly out of quarks. You
27:39
Speaker 3: made the protons first and then you fuse them together.
27:41
Speaker 1: Aren't you assuming a certain order, like that helium was
27:45
Speaker 1: made out of two protons. But could like you know,
27:47
Speaker 1: six quarks have come together to instantly make a helium
27:51
Speaker 1: atom without ever being two protons in the middle.
27:56
Speaker 3: Yeah, great question. The standard story is that you start
27:59
Speaker 3: with protons and neutrons. Neutrons are crucial here because onder
28:02
Speaker 3: a few stuff together. You need the neutrons to be
28:04
Speaker 3: like a buffer between the protons. You can't just fuse
28:07
Speaker 3: two protons together to make helium. You end up making
28:10
Speaker 3: like helium three in helium four because you need those
28:12
Speaker 3: neutrons to keep those protons from being so close together.
28:16
Speaker 1: But it's still helium, isn't it.
28:18
Speaker 3: It's still helium because you only have two protons. I'm saying.
28:21
Speaker 3: You don't just make two protons together. You also need
28:23
Speaker 3: those neutrons. So in order for the scenario where you
28:25
Speaker 3: make helium from nothing, you also have to make those
28:29
Speaker 3: neutrons at the same time. But it is possible, Like
28:32
Speaker 3: I think it's unlikely. I think it's much more likely
28:35
Speaker 3: for protons and neutrons to be made first and then
28:38
Speaker 3: come together to make helium. But technically it's not impossible.
28:42
Speaker 3: You have this big soup of quarks and gluons, and
28:44
Speaker 3: as it's cooling, it is possible for an entire helium
28:48
Speaker 3: atom to coalesce out of that soup without ever having
28:51
Speaker 3: been hydrogen.
28:53
Speaker 1: M And you can keep going right, like, maybe some
28:56
Speaker 1: carbon also was created spontaneously. Maybe even some uranium was
29:01
Speaker 1: created spontaneously in the Big Bang. Is that possible.
29:04
Speaker 3: It's possible. Now, uranium is unstable, so if you did
29:06
Speaker 3: make primordial uranium, it would have decayed, but you could
29:09
Speaker 3: have made like primordial lead, which is the heaviest stable element.
29:12
Speaker 3: Now we're talking about really really tiny possibilities. And the
29:15
Speaker 3: only reason we can't say it's totally impossible is because
29:18
Speaker 3: if the universe is really vast or even infinite, then
29:21
Speaker 3: anything that's super unlikely is gonna happen. And we want
29:25
Speaker 3: to give Trevor as accurate an answer as possible. And
29:29
Speaker 3: so it could be that there is an atom out
29:32
Speaker 3: there made of lead which was created during the Big
29:35
Speaker 3: Bang without ever having been hydrogen. But the overwhelming majority
29:39
Speaker 3: of stuff in the universe that's made of atoms almost
29:42
Speaker 3: certainly was hydrogen.
29:44
Speaker 4: First.
29:45
Speaker 1: The way you're saying there could have been one lead atom,
29:47
Speaker 1: but only one, like given the observable universe, but the
29:50
Speaker 1: universe that we can see. Do you actually have a
29:53
Speaker 1: number for your estimated probability of this happening or are
29:55
Speaker 1: you just kind of making it up in your head
29:57
Speaker 1: right now.
29:58
Speaker 3: No, I'm just saying it's possible that the is one.
30:00
Speaker 3: I mean, the probability of forming even helium directly out
30:04
Speaker 3: of those quarks is so astronomical I think I would
30:06
Speaker 3: bet against there being one in the observable universe. So
30:10
Speaker 3: now if you're going for a lead, yeah, I'm not
30:12
Speaker 3: going to take that bet either, but it is possible,
30:14
Speaker 3: so you can't rule it out.
30:16
Speaker 1: We are talking about the astronomical probabilities, all right, So
30:20
Speaker 1: then the answer is Daniel Wooden bet one. But it
30:23
Speaker 1: is still possible to create matter that was not hydrogen first.
30:27
Speaker 3: Yeah, exactly. And Trevor also asked this follow up question
30:30
Speaker 3: about like the nature of quantum particles. Can you think
30:33
Speaker 3: about them having a long history or this sort of
30:36
Speaker 3: a femarole, And this is a good philosophical question, you know,
30:39
Speaker 3: you could ask like when is a photon the same photon?
30:42
Speaker 3: If the photon bounces off of a wall, is it
30:44
Speaker 3: the same photon or was it absorbed and recreated, and
30:48
Speaker 3: that in the end is a philosophical question and sort
30:50
Speaker 3: of an arbitrary distinction. You know, the information in the
30:53
Speaker 3: universe flows through these particles and is preserved in those
30:57
Speaker 3: quantum states, whether you count it as the same particle
30:59
Speaker 3: or not. It's sort of like the question of whether
31:01
Speaker 3: the Star Trek transporter actually kills you and recreates you
31:05
Speaker 3: or transports you literally to another location. It's really more
31:09
Speaker 3: of a philosophical question than a physical one.
31:11
Speaker 1: I see, Trevor, I hate another question here in this question.
31:13
Speaker 1: He tried also to go recursive. Now is it still
31:18
Speaker 1: a question, Daniel? If it has two questions inside of it.
31:21
Speaker 3: That's a good question.
31:23
Speaker 1: Yeah, let's keep going. Now why is it a good question?
31:29
Speaker 1: All right? Well, Trevor, I think that answers your question.
31:31
Speaker 1: Thanks so much for sending that in. And now let's
31:33
Speaker 1: get to our third question, which is about the infinity
31:36
Speaker 1: of time time time. So let's dig into that. But
31:41
Speaker 1: first let's take another quick break. Or we're answering listening
31:56
Speaker 1: to questions here today, and our third question comes from
31:59
Speaker 1: I'll be.
32:00
Speaker 7: Hi, Daniel and Jorge. In any finite period of time
32:04
Speaker 7: being constrained by the laws of physics, finite extents in
32:09
Speaker 7: time or in space could never become infinite at least,
32:14
Speaker 7: I think, how does physics, then, given the proposed finite
32:20
Speaker 7: age of the universe, contend with the real possibility of
32:24
Speaker 7: an infinite universe? Would it have had to have been
32:28
Speaker 7: born infinite? If indeed it can't grow from finite to
32:33
Speaker 7: infinite size, and working backward from a finite or infinite size,
32:39
Speaker 7: how could that have grown from a universe that was
32:42
Speaker 7: infinitesmally small?
32:44
Speaker 1: Thank you all right? I feel like this question is
32:48
Speaker 1: also recursive in or at least it's giving me a
32:50
Speaker 1: bit of a headache here talking about the different infinities.
32:55
Speaker 1: I think what Abbi's asking is, do you need infinite
32:57
Speaker 1: time to make an infinite universe?
33:00
Speaker 3: Exactly? And I think obvious Struggling to reconcile two ideas
33:05
Speaker 3: that are out there in the sort of popular science universe.
33:08
Speaker 3: One is that the universe might be infinite, could go
33:11
Speaker 3: on forever and ever and ever, even beyond what we
33:14
Speaker 3: can see, So the full universe, beyond the observable universe
33:18
Speaker 3: could be infinite in extent. That's one idea, And the
33:21
Speaker 3: other is this conception of the Big Bang as the
33:24
Speaker 3: universe having started from a point that there was a
33:27
Speaker 3: tiny dot of stuff and everything flew out from that dot.
33:31
Speaker 3: That dot seems finite, and so I think Abby's wondering, well,
33:34
Speaker 3: how do you start with this finite dot then end
33:37
Speaker 3: up with infinite space filled with infinite stuff? That seems
33:40
Speaker 3: like a disconnect.
33:41
Speaker 1: Right, right, because I guess the way the Big Bang
33:44
Speaker 1: is usually percented, it does start with a dot, and
33:46
Speaker 1: a dot seems finite.
33:48
Speaker 3: Exactly, and there's a way to interpret that. It's being
33:50
Speaker 3: technically correct, but I think mostly it's misleading. People think
33:53
Speaker 3: of the Big Bang as this tiny dot, like smaller
33:56
Speaker 3: than an atom, containing all the matter in the universe,
33:59
Speaker 3: which then expands ended out into empty space, and people
34:02
Speaker 3: wonder like, well, how could that turn into something infinite?
34:06
Speaker 3: And the way that we actually think about the Big
34:07
Speaker 3: Bang is not in that sense at all. We think
34:09
Speaker 3: about it more in the way that we just described,
34:11
Speaker 3: And answer the last question. You start with potentially infinite
34:14
Speaker 3: space already filled with stuff, but there was no empty
34:18
Speaker 3: space back in the beginning, that everything was already filled.
34:21
Speaker 3: However much space there was, it was already filled with
34:24
Speaker 3: some hot, dense state, a state we can't explain. We
34:27
Speaker 3: don't understand where it came from. But the Big Bang
34:30
Speaker 3: describes the expansion of the universe from that point. So
34:33
Speaker 3: there's no empty space. Everything's already filled, and the Big
34:36
Speaker 3: Bang is not the explosion of stuff through that empty space,
34:39
Speaker 3: but the expansion of that space, which makes it colder
34:42
Speaker 3: and more dilute.
34:44
Speaker 6: Right.
34:44
Speaker 1: I think what you're trying to say is that, like
34:47
Speaker 1: we think of the Big Bang as a moment of creation,
34:49
Speaker 1: but you're saying that the Big Bang is not really
34:52
Speaker 1: when the universe was created. It's just when the universe
34:55
Speaker 1: expanded from being super compressed to being less compressed. The
35:00
Speaker 1: universe was there already and it was infinite.
35:02
Speaker 3: Yeah, exactly. And that's because we know there's a limitation
35:05
Speaker 3: to our theories. Like we can talk about quantum fields
35:07
Speaker 3: and all that stuff describing space, and that works up
35:10
Speaker 3: to a point, up to a certain density of the universe,
35:13
Speaker 3: beyond which our theories break down. It's at that point
35:16
Speaker 3: when everything is so dense that you can't really ignore
35:19
Speaker 3: gravity anymore. You need a theory of quantum gravity to
35:21
Speaker 3: describe the universe that is that dense. So before that,
35:25
Speaker 3: we don't even try to explain. So we start our
35:27
Speaker 3: history of the universe the first moment that we think
35:30
Speaker 3: our theories can describe, when the universe is super hot
35:33
Speaker 3: and super dense, but we think we can describe it
35:35
Speaker 3: used in quantum field theory. Before that, we have no idea,
35:38
Speaker 3: question mark, question mark, inflation, instantans, who knows, squiggly ons, whatever.
35:43
Speaker 3: But the history of the universe begins in the first
35:45
Speaker 3: moment we can describe, and the big Bang is the
35:48
Speaker 3: evolution of that universe, the expansion, the cooling and coalescing
35:53
Speaker 3: into particles, et cetera, et cetera.
35:54
Speaker 1: I think maybe what Auby is also trying to kind
35:57
Speaker 1: of grapple in their heads, is this idea of find
36:00
Speaker 1: time right, because a lot of physicists say that time
36:03
Speaker 1: started with the big Dang, possibly, and that there was
36:06
Speaker 1: no time before. If you sort of run the clock backwards,
36:10
Speaker 1: at some point, there was no time, and so what
36:13
Speaker 1: was the universe back then exactly?
36:15
Speaker 3: And that's extrapolating past that super dense point using just
36:19
Speaker 3: general relativity, saying well, what if general relativity is correct
36:22
Speaker 3: and that's the way time and space works, and we
36:25
Speaker 3: can ignore the unignorable quantum effects. That's what general relativity predicts.
36:29
Speaker 3: Predicts that time begins in the singularity of density. But
36:33
Speaker 3: that's sort of ridiculous extrapolation. We know that quantum theory
36:36
Speaker 3: needs to be accounted for there. So yeah, if you
36:39
Speaker 3: extrapolate general relativity beyond where we think it's relevant, then
36:43
Speaker 3: you get this prediction that time begins at some certain point,
36:46
Speaker 3: which is also difficult to grapple with. But that's not
36:48
Speaker 3: something we're confident doing because we know the theory breaks down.
36:51
Speaker 1: I see. So the answer is we don't know.
36:54
Speaker 3: The answer is we don't know, and we think it's
36:56
Speaker 3: possible that the universe began infinite, that that first moment,
36:59
Speaker 3: at least that we can describe the universe was already infinite,
37:03
Speaker 3: filled with an infinite amount of stuff that then expanded
37:06
Speaker 3: and cooled into a universe that was larger. Right, you
37:10
Speaker 3: can take an infinite universe and make it larger just
37:12
Speaker 3: by stretching it, so you can create new space everywhere
37:16
Speaker 3: in that universe, making it effectively larger and colder. So
37:20
Speaker 3: that's how we get to an infinite universe today, is
37:22
Speaker 3: that you start with an infinite universe. Abby's totally correct
37:25
Speaker 3: that if you start with a finite sized universe, you
37:28
Speaker 3: can't then have an infinite universe. Today, we don't know
37:31
Speaker 3: if the universe is infinite. We can only see a
37:33
Speaker 3: certain distance out there. We know the universe is huge
37:36
Speaker 3: and vast. It might be infinite beyond that horizon, or
37:39
Speaker 3: it might be that it's finite.
37:41
Speaker 1: Well, I think maybe Abby is also maybe posing the
37:43
Speaker 1: question like what happens if you take an infinite universe
37:47
Speaker 1: and you squish it down to an infinitely small size.
37:51
Speaker 1: Does it become then a finite universe? Because as we
37:54
Speaker 1: all remember from Calculus one, if you divide infinity by infinity,
37:58
Speaker 1: it depends, But one of the positive abilities is that
38:00
Speaker 1: you get a finite number.
38:02
Speaker 3: You get a finite number in the limit, right, which
38:04
Speaker 3: would take technically an infinite amount of time. The only
38:07
Speaker 3: way to go from a finite universe to an infinite
38:09
Speaker 3: universe is taking an infinite amount of time.
38:12
Speaker 1: But if you go backwards, are you saying it would
38:14
Speaker 1: take an infinite amount of time to compresent infinite universe
38:18
Speaker 1: an infinite.
38:19
Speaker 3: Amount exactly into a finite point?
38:21
Speaker 1: But you know, I think the universe is time right,
38:23
Speaker 1: like the universe not really doing anything else? Do universe
38:26
Speaker 1: do it?
38:27
Speaker 3: It's possible. I mean that state we talked about, that
38:29
Speaker 3: initial state that we can't explain. We know how far
38:32
Speaker 3: back that was. That was fourteen billion years ago. What
38:35
Speaker 3: happened before that? There could be an infinite amount of
38:37
Speaker 3: time before that, or there could be just five minutes.
38:39
Speaker 3: We don't know. Right, it's possible that deep in the
38:42
Speaker 3: infinite past, if it exists, there is a finite origin
38:46
Speaker 3: to the infinity of the current universe.
38:48
Speaker 1: Mmm. So I'll be sort of right. You can sort
38:52
Speaker 1: of go from a finite universe to an infinite universe if.
38:54
Speaker 3: You have infinite time. You have to assume infinity somewhere.
38:58
Speaker 3: You can't go from a finite universe to an infinite
39:00
Speaker 3: universe in finite time.
39:02
Speaker 1: But maybe the universe had infinite time.
39:04
Speaker 3: Maybe it did. We just don't know what the squigglyons
39:07
Speaker 3: were doing before that moment. We can't describe.
39:09
Speaker 1: Yeah, the bits on I think you mean.
39:12
Speaker 3: The university news.
39:15
Speaker 1: Yeah, the Albinos. We'll call them obinos in honor of Alby,
39:20
Speaker 1: who apparently sparked the revolution in physics starting today.
39:24
Speaker 3: Congratulations on your future Nobel prizes, infinite numbers of them.
39:27
Speaker 1: No, no, we get the Noble awesome congrati. But Abby
39:30
Speaker 1: just gets to be named. Yes, yes, let's be clear here,
39:34
Speaker 1: or at least I get it. I don't know if
39:36
Speaker 1: I'll share it with you.
39:37
Speaker 3: Well, I hope you have a nice tux.
39:40
Speaker 1: I have to buy one. I hope it doesn't cause
39:42
Speaker 1: it an infinite amount of money, though.
39:44
Speaker 3: Just get the T shirt tuxedo. I think that's probably
39:46
Speaker 3: fine for a cartoonist.
39:47
Speaker 1: Oh boy, I wonder how many physicists have been tempted
39:50
Speaker 1: to do that, you know, like if one of these
39:53
Speaker 1: hipster physicists that you see on TV, they're like, they
39:55
Speaker 1: get a Nobel price, but they go into talks or
39:58
Speaker 1: are they too cool for that?
40:00
Speaker 3: I bet there's like a Swedish sniper and ready to
40:02
Speaker 3: take them out just in case they try that.
40:03
Speaker 1: Oh jeez. All right, Well, I think that answers obvious
40:10
Speaker 1: question depends on your infinities, but also it sort of
40:13
Speaker 1: depends on maybe the true nature of the universe, whether
40:18
Speaker 1: infinities are allowed, whether quantum mechanics at some point breaks
40:22
Speaker 1: this idea of things being infinitely small.
40:25
Speaker 3: Real question is what happened before that hot dense state.
40:28
Speaker 3: The first thing that we can describe with our laws
40:30
Speaker 3: of physics, and in the end, it all comes down
40:32
Speaker 3: to quantum gravity, the biggest open question in modern physics.
40:36
Speaker 3: How do we reconcile gravity and quantum mechanics so we
40:39
Speaker 3: can describe a state denser that can be described with
40:42
Speaker 3: our quantum theory.
40:43
Speaker 1: All right, well, thanks to everyone who asked their questions
40:45
Speaker 1: here today. We hope you enjoyed that. Thanks for joining us.
40:53
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40:56
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