Listener Questions 53: Strong force, primordial atoms and infinities

00:00:08
Speaker 1: Hey, Daniel, how long have we been doing this podcast?

00:00:10
Speaker 2: Now?

00:00:10
Speaker 3: Oh? Man, I'm not sure. Kind of feels like forever.

00:00:14
Speaker 1: Do you think we could go on forever?

00:00:15
Speaker 3: I don't know. I don't think we're going to run out of topics.

00:00:18
Speaker 1: You think there's an infinite number of questions we can talk about in physics.

00:00:23
Speaker 3: I think you could just keep asking why forever? Yeah?

00:00:26
Speaker 1: Why do you think that is?

00:00:28
Speaker 3: I think you just proved my point.

00:00:29
Speaker 1: Wait, what do you mean why? Q ed you pretended to say just because I said so ardude.

00:00:37
Speaker 3: Because the universe says so. Universe is the ultimate?

00:00:41
Speaker 2: Dad or Mom?

00:00:57
Speaker 1: Hi, I'm orham Mack, cartoonists and the author of Oliver's Universe.

00:01:01
Speaker 3: Hi, I'm Daniel. I'm a particle physicist, a professor at UC Irvine, and I think I'll always be asking why, why?

00:01:07
Speaker 4: What?

00:01:09
Speaker 3: Why this universe and not some other universe. Imagine some moment in the deep future when we see the final theory of the universe that describes the most fundamental basic bits. I think people are still going to look at that idea and wonder, why does it work this way? Why couldn't it have been different?

00:01:27
Speaker 1: What if you get to the end Daniel, and you figure it everything out, and the answer is just because.

00:01:35
Speaker 3: Is that really an answer?

00:01:36
Speaker 1: Though it is, I give it to my children all the time.

00:01:40
Speaker 3: I don't know if that's an answer or a cop out. It kind of means like there is no answer, you know. One version of the answer is, Look, the universe could have been lots of different ways. It just is this way, which means there's fundamental randomness, not just in the operation of the universe, but in the very laws that government.

00:01:56
Speaker 5: Right.

00:01:57
Speaker 1: But it's still an answer that wouldn't be satisfying. Ye, going to sleep soundly that night, and just one night after that, you'll be totally fine. I see how deed your physics roots go.

00:02:08
Speaker 3: I'll have one long dark night of the physics soul.

00:02:11
Speaker 1: Yeah, and then you're over it. Yeah, that's fine.

00:02:15
Speaker 3: You've got to embrace stuff and move on. You know, no point in holding grudges against the universe.

00:02:20
Speaker 1: Well, speaking of moving on, Welcome to our podcast, Daniel and Jorge Explain the Universe, a production of iHeartRadio.

00:02:26
Speaker 3: In which we refuse to move on until we understand something and explain it in an understandable way to you. We think, we hope we pray that the universe is understandable, is explainable, is digestible by our petty little human minds, and we do our best to bring you up to the forefront of human knowledge and the abyss of human ignorance.

00:02:45
Speaker 1: That's right, because there is still a lot that we don't know about the universe, a lot to discover, a lot to find out, a lot to explore. In fact, maybe we should rename this podcast Daniel and Jorge wonder why, although is that taken? Is that taken?

00:02:58
Speaker 3: It's a great name for a show, and somebody should really do that.

00:03:01
Speaker 1: Yeah, somebody should make a yeah TV show maybe for kids.

00:03:04
Speaker 3: Yeah, exactly, Yeah, replace our names with some kids name or something. I don't know, we'll figure it out.

00:03:08
Speaker 1: Yeah, an awesome girl's name. Perfect. I'm sure they'll give us a show, even though we've never made one before.

00:03:16
Speaker 3: Now you're just being ridiculous.

00:03:18
Speaker 1: Yeah, who would do that?

00:03:19
Speaker 3: There are a lot of amazing mysteries in the universe things to wonder about, not just whether two total nubes can make a TV show on PBS, but questions about the nature of the universe, how it works, why it works this way not some other way. Unfortunately, we have not yet run out of those questions.

00:03:35
Speaker 1: Yeah, it seems that human curiosity is sort of endless, and we have evidence of that from all the questions that the podcast receives from listeners.

00:03:43
Speaker 3: Because the process of doing science is tapping into those human questions to wonder, why is it this way not some other way? How does this idea fit with that other idea? Can I click them both together in my head? When they don't quite fit? That's an opportunity to learn something, maybe to reveal something about the universe. That's how science moves forward. People asking questions, and those people are podcasters, scientists, television show producers, and everybody else who wants to understand the universe.

00:04:09
Speaker 1: Yeah, we get lots of questions, and sometimes we actually answer those questions here on the podcast, questions that we feel everyone would enjoy thinking about and finding out what the current answer and science is.

00:04:21
Speaker 3: That's right. But even if your question doesn't make it to the podcast, you will still get an answer. I will write back to you and try to help you understand. So please, everybody, don't be shy write to us to questions at Daniel and Jorge dot com. We really will right back.

00:04:36
Speaker 1: So to the end the podcast, we'll be tackling listener questions Number fifty three Daniel Hoffen. Do we do these now? About every month we answer listener questions.

00:04:49
Speaker 3: We used to do it about every month, but we've been getting a lot more questions recently, so I've uped it to almost every week to try to catch up.

00:04:55
Speaker 1: Wow, what do you think is causing this increase in questions?

00:05:00
Speaker 3: Good question, I'll add it to the list.

00:05:02
Speaker 1: We'll spend an episode talking about why we get more questions in the episode, and then we'll implode. We'll implode from the paradoxical nature of this.

00:05:10
Speaker 3: The infinite recursion in that question will generate information density that creates a black hole podcast.

00:05:15
Speaker 1: Yeah, and then we'll be able to go on forever.

00:05:19
Speaker 3: That's called the singularity.

00:05:20
Speaker 1: Because then the next episode will be yes, how are we doing a podcast while we're getting questions?

00:05:26
Speaker 3: I can just see it alien anthropologists in the future trying to figure out how human civilization ended in a podcast singularity.

00:05:33
Speaker 1: Well, hopefully we're not the end of civilization, but maybe the beginning of a lot of people's questioning about the universe. And so we have three awesome questions here today that we're going to try to answer or at least talk about great questions about the strong force, about the creation of matter, and about the infinity of time. Hopefully this podcast will not be an infinite length of time, but we hope your love for it is infinite no matter what kind of matter we talked about.

00:06:01
Speaker 3: I hope anti matter doesn't lead the anti love.

00:06:03
Speaker 1: Yeah, that would be a strong statement. All right, let's dig into our first question, and this one is from Emily.

00:06:09
Speaker 3: We actually have two questions here from Emily and from Sarah that asked related questions. I thought we could answer all together a double question.

00:06:17
Speaker 4: All right, Hi, Daniel and Joje. Here's Emily and I have a few questions about the strong force. First, how does the strong force even really work? And how can it be that it gets stronger with the distance? Does that ever end? As in, is there a maximum strength to the strong force? Because it cannot get infinitely strong?

00:06:45
Speaker 3: Right?

00:06:46
Speaker 4: If it did, we could never break apart of proton, could we? And one more question, If I had the strength to pull two quarks.

00:06:58
Speaker 6: Away from each other, would I at some point need infinite strength to keep pulling? Thanks for answering my question. I really like your podcast. Keep up the great work.

00:07:12
Speaker 7: Hi.

00:07:13
Speaker 8: I want to ask about the strong force. What is the strong force? What does it do? Why is it so strong? Why is it so difficult to understand and calculate? And why is it range considered shorter than electromagnetisms.

00:07:34
Speaker 1: All right, some pretty strong questions here, Daniel. Do you think we're strong enough to answer it?

00:07:39
Speaker 3: I hope. So the strong force is tricky. It is complicated stuff, and these are great questions trying to get intuitive understanding of how it all works.

00:07:48
Speaker 1: I like how she phrased the question Emily here, how does that even work?

00:07:54
Speaker 3: How does it all even work? Can we just describe it? How can we actually explain it?

00:07:59
Speaker 1: All? Right? Well, we had two questions that we'll tackle one at a time. Daniel, How does the strong force work? And why does it get stronger with distance?

00:08:07
Speaker 4: So?

00:08:08
Speaker 3: The strong force is a force between any particles that have color charge. Color charges is like a version of electric charge. You know how electrons have negative charge and protons have positive charge, and that's how you know they attract each other or to electrons will repel each other. In a strong force, we have a different kind of charge we call it color, and any particles that have these color we say feel the strong force. This is just kind of descriptive the way we gave labels too particles to describe their charge, to explain the forces we see pulling and pushing between them. We give these colored labels to quarks to describe the forces that we describe between them.

00:08:46
Speaker 1: Well, maybe taking a step back, the strong force is one of the four fundamental forces that businesses have noticed about the universe, and these are the forces that pull and push matter together or apart.

00:08:57
Speaker 3: That's right. It depends a little bit how you count the forces. Some people say two, some people say three, some people say four. And the four force version you have gravity, which is not really a force, and then you have electricity and magnetism as one force, the third force, and then the strong forces the fourth and the more simplified version, we say gravity is not a force, you don't count it. Electricity and magnetism have been combined with the weak force into the electro weak force, and then the second force is the strong force. So in the sort of unified version, you really only have two forces, electroweak and the strong force.

00:09:31
Speaker 1: And so the strong force is the one that pushes and pulls quarks, right.

00:09:36
Speaker 3: Yeah, that's right. Anything with a color charge, which means quarks and also gluons, electrons and muons, and those particles don't have a color charge, so they just don't feel a strong force the way a neutral particle doesn't feel an electric field.

00:09:49
Speaker 1: Okay, and so part of the Emily's question is how does it get stronger with distance? So does it get stronger with distance? Meaning if you pull the quarts apart, they're actually going to be pulling the dwarf each other or apart more.

00:10:02
Speaker 3: Yeah, it's really weird and very counterintuitive with gravity and with electromagnetism. If it's attracting two particles and you try to pull them apart, it gets easier as you get further apart. Imagine a proton an electron and you're holding onto them with tweezers and you're pulling them apart. As you succeed in pulling them further and further apart, the force on them gets weaker and it gets easier and easier. But with a strong force, we notice something different. We notice that after a certain distance, the force stays constant, doesn't actually grow with distance. It stays constant. So after about like the width of a proton, if you pull two quarks apart, the force on them is the same no matter how far apart you pull them.

00:10:39
Speaker 1: Wait, what so it doesn't get stronger with distance only for a little bit.

00:10:43
Speaker 3: It decreases with distance until you get about a proton's width apart, and then it stays constant. It doesn't fall off like one of our are square, the way electromagnetism does.

00:10:53
Speaker 1: Oh so the strong word doesn't get stronger with distance.

00:10:56
Speaker 3: Doesn't get stronger with distance in the sense that the force doesn't increase, but the amount of energy stored in that bond does because forces like the slope of the energy, and so the energy is actually just growing and growing as those two quarks pull apart.

00:11:10
Speaker 1: But the ford doesn't get stronger, right, doesn't get stronger. There's just more potential the more you pull them apart. You just like maybe you have more gravitational potential the higher you go up a ladder.

00:11:21
Speaker 3: Yeah, exactly, And this feels weird compared to like electromagnetism, but it's not so unintuitive.

00:11:26
Speaker 4: You know.

00:11:26
Speaker 3: You take a rubber band, for example, and you pull on it. The force doesn't drop as the rubber band gets stretchier and stretchier. Right, So there are some kinds of analogies we have in the everyday world. But Emily's probably wondering, like, why does this happen? How does it work this way? And that's not something we really understand. This is just our description of what we see happen between particles.

00:11:46
Speaker 1: Part of our question is is there a maximum to the strong for it? I guess she was imagining that the strong force was like a rubber band. The more you pull it apart, the stronger it gets. And so she's wondering, is there a maximum to this force? Can it just be infinite if you pull the two things apart infinitely? But it sounds like you're saying that this wouldn't really happen.

00:12:06
Speaker 3: It wouldn't really happen because the energy can't grow to infinity. Like, as you pull these things apart, the four states constant, but the energy stored in that bond just grows and grows and grows and grows. But at some point there's so much energy in that bond that the universe prefers to transfer that energy into mass, to convert that energy into quarks because quarks are actually pretty light. They don't take a lot of energy to make. So the universe, which prefers to spread energy out rather than have it concentrated in one bond or in one state, will prefer to create a bunch of quarks out of that energy. So you have these two quarks that you're pulling apart. The universe prefers to create more quarks to shorten the distances between quarks, spending that energy to create the mass and reducing the energy of the bonds.

00:12:48
Speaker 1: Well, what so I take two quarks they're held together by the strong force, I pull them apart, and at some point, like what kind of distance that we're talking about, like a meter.

00:12:58
Speaker 3: We're talking about like the width of a proton.

00:13:00
Speaker 1: Oh okay, so a little smaller you pull them apart the width of a proton, and then what like new quarks pop up in the middle. You'd have to pop up two new ones, right, One of the two new ones is going to be attached to one of my original protons, and the other new one is going to be attached to the second of my original quarks.

00:13:18
Speaker 3: Yeah, exactly, And we do this all the time at the Large Hadron Collider we create a quark and antiquark pair with a lot of energy, so they're flying apart super duper fast, almost at the speed of light, and very quickly. What happens between them is you create another quark antiquark pair. So instead of having a quark anti quark a certain distance apart, now both of those have a new partner to be bound with at half the distance, and then those start to fly apart and that band snaps. So you get this whole shower of quarks and anti quarks being created. All that energy is converted into a whole stream of new particles, and they like to stay close together to minimize the energy stored in those bonds.

00:13:55
Speaker 2: Hmmm.

00:13:56
Speaker 1: Interesting, all right, so then you couldn't get to infinity at some point. It's like the rubberband breaks, yeah kind of, yeah, exactly.

00:14:03
Speaker 3: It's like the rubber band prefers to snap rather than to stretch out to infinity. And so in principle, you could have a universe where two quarks are infinitely far apart, holding infinite energy, but in practice the universe prefers to spread that energy out. It's basically just entropy that very unlikely to happen. The universe prefers configurations with more probability, which means the energy is more spread out, and so it replaced that infinite energy bond with a lower energy bond and a bunch of quarks.

00:14:31
Speaker 1: So I guess the strong force is not that strong. It snaps at some point.

00:14:36
Speaker 3: It's so strong and energetic that it usually breaks down.

00:14:39
Speaker 1: Yeah, all right, then, now Sarah's question our second question of this question. See you're the one introducing recursion here. We have two questions inside of one question. Sarah's question is why is the strong for so strong? Now? Is there actually an answer to that?

00:14:54
Speaker 3: There's not a great answer to that. There's a terrible answer and a less terrible answer. Totally terrible answer is this is just what we measure. We go out in the universe. We measure the force between particles. We can measure the strength of stuff. We can say, for example, gravity is much weaker than electromagnetism, because if you take two particles, you mostly feel electromagnetism between them rather than gravity. Gravity is so much weaker. In the same way, we can compare the strength of electromagnetism to the strong force and say, hey, between two quarks which have both kinds of charge, which force is dominating the interaction. So those are just measurements we make out in the universe, just numbers the way we measure like the speed of light or planks constant. These are just things we see in the universe.

00:15:36
Speaker 1: So basically, you're saying because you said so, because that's.

00:15:39
Speaker 3: What the universe is showing us. The slightly less terrible answer is that we think at an earlier moment in the universe, all the forces had the same strength. We talked about this recently on the podcast. A lot of these forces, their strength depends on energy, like how fast particles are going, how much energy they have, the forces get stronger or depending on the energy and the energy density of the universe varies with time, like it used to be hotter and more energy dense in the early universe. So we think in the early universe, if you sort of rewind the clock, a lot of these forces might have had the same strength. So it might be that very early in the universe the strong force and the electroweak force were both the same strength, and then something happened when the universe cooled, it like cracked in an asymmetric way to give one of them more strength and one of them less strength.

00:16:29
Speaker 1: WHOA, So there was like an option the universe had. Is that what you're saying, Like it could have been a different way, but somehow it broke that way, or it could it have only broken this way?

00:16:38
Speaker 3: Yeah, we don't understand that. This is something in physics we call spontaneous symmetry breaking, when the universe had a symmetry, a balance, and then it cracked as it cooled. A famous analogy for this is like you sit down at a dinner table and you have silverware to your left and silverware to your right. Which one do you pick? Well, if you pick to your left, then everybody's going to have to pick to their left. If you pick to your right, everybody's gonna have to pick to your right. And another example of this is the Higgs boson. As the universe cools, all the particles started out having no mass, but then the Higgs field gives mass to particles, but not in a symmetric way. It made like the W and the Z very massive and left the photon massless. This is called electroweak symmetry breaking. So as the universe cools and enters another phase, some of these symmetries crack in a way we don't fully understand.

00:17:24
Speaker 1: So then are you saying that at different universe where the strong force wasn't a strong that's a totally plausible, mathematically possible universe that we could have been living in. But somehow we're living in this universe where the strong force is strong.

00:17:37
Speaker 3: It might be that those universes are equally possible, or it might be that there's a reason that it cracked this way and not some other way. It's not something that we currently understand, so it's possible, But it might be that we discover that there is a reason why the strong force cracked this way and the weak forces cracked the other way. Are currently we don't know why it's so strong?

00:17:55
Speaker 1: Do you think it was random?

00:17:57
Speaker 3: There's so many different theories, some that control it, some that even random. The true description of the universe is probably something we haven't even thought of yet, so it's still a deep question.

00:18:07
Speaker 1: I think the real question is if the strong force hadn't been so strong, would you just still have called it the strong force?

00:18:14
Speaker 3: We probably would have named it terribly. That's for sure.

00:18:17
Speaker 1: It could have been strong force.

00:18:20
Speaker 3: We have a pretty weak game in naming things. That's what's constantly across the multiverse. It a strong bias here because the strong force is so strong, it makes it really difficult to use. To another part of Sarah's question, why is it so difficult to do these calculations? And the reason is its strength. It's hard to do calculations with a force that likes to pop off all the time. It's crazy reactive because it makes it much more sensitive to getting the details wrong. Get a little detailed wrong, it propagates to a much bigger mistake. That's not true for the weak force, where mostly things just fade out anyway. So you make a little mistake, it's going to fade away and not affect your calculations. The strong force is like recursive, It builds on itself, and so little mistakes become bigger mistakes.

00:19:02
Speaker 1: M Terry volatile huh, yes, exactly. All right. Well, so then to answer Sarah's question, it's either because if we said so, or we don't know.

00:19:12
Speaker 3: Either there's no answer or there's an answer we haven't found yet.

00:19:15
Speaker 1: That basically covers every possibility because just because.

00:19:21
Speaker 3: Keep digging, Sarah, keep digging.

00:19:22
Speaker 1: All right, Well, thank you, Emily and Sarah for those great questions. Now let's dig into our second question, and this one is about the creation of matter, So let's dig into that. But first let's take a quick break. All right, we're answering listener questions here, and our second question comes from Trevor.

00:19:52
Speaker 5: Hey, guys, this is Trevor from Pittsburgh, Pennsylvania. I appreciate you taking my question. I've been thinking lately about the origin of the matter that we come across in everyday life that just makes us up and makes up all of our stuff, right, and how most of it probably came from stars that fuse hydrogen into heavier elements naturally. My presumption when I was thinking about this was that most of the particles that make all this stuff around us up probably spent some or possibly even most of their existence as parts of hydrogen atoms before those atoms were fused into heavier elements. But the more I think about it, the less confident I am in this presumption. Do we actually know anything about how much of the normal matter that exists today has at some point been a part of a hydrogen atom, And if there is matter that has never been a part of a hydrogen atom. Why not? And where is it? I think this whole line of questioning brings up yet another question. Does it even make sense to think of quantum particles as having a long history like this or are they more kind of ephemeral in nature. I really look forward to hearing what you guys have to say on this. Thanks again.

00:21:02
Speaker 1: Well, it seems like Trevor here is asking about the origin of matter, and the part I didn't understand is exactly whether it could have been part of the hydrogen atom. What does that mean?

00:21:11
Speaker 3: I think he's asking whether all the heavier bits of stuff that are out there, iron and lithium and uranium was once hydrogen. Like is it possible that uranium was just made from nothing? Or was every atom made from hydrogen atoms fused together? Is the history of every single atom that it was once hydrogen I see?

00:21:31
Speaker 1: Or do we have some like original atoms out there that were made heavy from the very beginning of the universe?

00:21:37
Speaker 6: Yeah?

00:21:38
Speaker 3: Exactly, Like is there any primordial uranium in the universe that was never hydrogen? Whereas hydrogen the only path to becoming an atom?

00:21:46
Speaker 1: Right, And we actually talked about this in our last recording.

00:21:48
Speaker 3: Did we Yeah, we talked about this in the Origin of Matter a few times. It's a really fascinating concept. It's incredible to me that we understand so much about the early universe that we can talk about how madam was and how it was fused, like down to the seconds and microseconds.

00:22:03
Speaker 1: Well, I guess maybe there's two questions here. Is one, can you make heavier matter instantly just from like the basic building blocks of the universe without going through the hydrogen atom? And the second question is what actually happened in the Big Bang? Did something like that happen or did all the matter in the universe go through hydrogen? First?

00:22:22
Speaker 3: Yeah, so let's trace the sort of early history of the universe to answer this question. You start out like, before there were any particles, you know, what was in the universe. Well, the furthest back we can go is to say there was some very hot dense state. We don't know where it came from, we don't know how it was made, we don't know what came before that. Just start with the assumption you have some hot dense state, and everything expands. That hot dense state becomes less hot and less dense, so it becomes colder and more dilute. So you have all this energy in these frothy quantum fields. As it cools down, you can start to talk about particles emerging from these fields the way like a room that's flooded is just filled with water, and then as you drain it, you end up with like droplets on the floor. So now the universe is sort of filled with the most fundamental particles quarks and electrons and stuff like that.

00:23:11
Speaker 1: Before it was just pure energy like this is before there were even quantum fields. Like the universe was so nuts so that you couldn't stand being there.

00:23:19
Speaker 3: We don't know what comes before fields. The nutso state of the universe is not something we can even describe. There's some vague theories about it, you know, inflotons decaying into quantum fields, but it's all very speculative. In question markye, the first moment we can describe is the universe filled with quantum fields. But those fields are so washed with energy that it doesn't make sense to talk about particles yet in those fields. It's only as those fields calm down and cool that it makes sense to talk about particles. As ripples in those fields, and.

00:23:47
Speaker 1: They calm down, cool because they were getting stretched.

00:23:50
Speaker 3: Out, right, Yeah, because as the universe expands, there's the same amount of matter in it, so that matter gets more dilute, right, and so you end up with particles rather than just huge piles of enery.

00:24:00
Speaker 6: Right.

00:24:00
Speaker 1: But those first particles are not atoms. They're the building blocks of atoms, meaning quarks. Right, So before you even had an atom, you had a whole bunch of quartz floating rep.

00:24:09
Speaker 3: Yeah, not just quarks. You have quarks, and you have gluons, you have photons, you probably have dark matter, you have electrons. You have all the sort of basic building blocks. And we don't know that these actually are the most basic building blocks. Just our current theory could be that quarks are made of something else, quigglyons, and the squiglyons were made first. But in our current description you end up with quarks and gluons and photons and dark matter. No atoms yet. Absolutely, it's still too hot for atoms to even form.

00:24:36
Speaker 1: Right, So we had the basic particles quarks, gluons, and then eventually those quarks fuse together to form protons and neutrons exactly.

00:24:44
Speaker 3: The strong force is pulling on all those quarks. There's a huge amount of energy. But then as things cool, the strong force pulls those quarks together to make protons and neutrons and other kind of bound states of quarks. Here's a strong force at play pulling those quarks together. Doublets of quarks like quark antiquark pair, we'll give you pions. Triplets of quarks will give you protons and neutrons. That's the moment when you go from like free particles to bound particles, when the universe gets cold enough to bind those quarks together.

00:25:14
Speaker 1: Right, right, Well, assuming that quarks and gluons and photons are fundamental particles, right, isn't it, there are still the possibility made they're made out of smaller particles.

00:25:23
Speaker 3: Yeah, exactly. If they're all made out of squiglyons, then first you start with the squigglyons, which then coalesce into the quarks and gluons, et cetera.

00:25:30
Speaker 1: Is that the official name squigglions?

00:25:33
Speaker 3: What's the macaltons, the wacinions? You know, who knows who knows ons?

00:25:39
Speaker 1: Just to be clear, that's not the official name, right, she made that up.

00:25:42
Speaker 3: I'm not aware of any theory of squig lyons. I just made that up. Yeah, did it sound official?

00:25:47
Speaker 1: If it's every thing, I think you should get credit for it.

00:25:50
Speaker 3: Oh yeah, you like that name, squiglyons. You think we should be teaching generations as students about it.

00:25:55
Speaker 1: I think it's as good as quarks and gluons.

00:25:59
Speaker 3: You know, there's a big fight about the name of quarks. There was one guy I wanted to call them quarks and somebody else wanted to call them aces and the quarksky one Mmmm. Yes, yes, I.

00:26:07
Speaker 1: Think we covered this in depth already, all the quarks of it.

00:26:11
Speaker 3: But that moment when quarks come together into protons and neutrons already have hydrogen. Essentially, the proton is a hydrogen nucleus, so physicists consider a proton.

00:26:21
Speaker 1: Hydrogen even though it doesn't have an electron to make it a whole atom.

00:26:25
Speaker 3: Yeah, we distinguish between the hydrogen ion just the proton, and the neutral hydrogen atom, which is a proton and electron.

00:26:33
Speaker 1: So wait, are you saying that a proton is an atom? So why do we even have the word proton?

00:26:38
Speaker 3: Why do we even have the word proton? Well, who's the one getting philosophical there?

00:26:41
Speaker 2: Man?

00:26:41
Speaker 3: Why don't we even think about protons. We use protons to count which atoms are which right, Helium has two, lithium has three, et cetera, et cetera. So it's definitely a thing in the universe we want to identify. But when you have only one of them, we consider that hydrogen. Even if you don't like that explanation, you think like, protons are not hydrogen yet, then those protons do something funky well before they find their electrons. In those first few moments, there is still enough energy for those protons to come together and make heavier elements like helium. So in the first few moments after the Big Bang, you make protons, you make neutrons, and then you also squeeze those protons together to make helium. So then the question is that helium did it once used to be hydrogen? That's essentially what Trevor is asking. If you made primordial helium right then during the Big Bang fusion, do you still count that as having been hydrogen? I say yes, because you didn't make the helium directly. You didn't make like a proton proton pair directly out of quarks. You made the protons first and then you fuse them together.

00:27:41
Speaker 1: Aren't you assuming a certain order, like that helium was made out of two protons. But could like you know, six quarks have come together to instantly make a helium atom without ever being two protons in the middle.

00:27:56
Speaker 3: Yeah, great question. The standard story is that you start with protons and neutrons. Neutrons are crucial here because onder a few stuff together. You need the neutrons to be like a buffer between the protons. You can't just fuse two protons together to make helium. You end up making like helium three in helium four because you need those neutrons to keep those protons from being so close together.

00:28:16
Speaker 1: But it's still helium, isn't it.

00:28:18
Speaker 3: It's still helium because you only have two protons. I'm saying. You don't just make two protons together. You also need those neutrons. So in order for the scenario where you make helium from nothing, you also have to make those neutrons at the same time. But it is possible, Like I think it's unlikely. I think it's much more likely for protons and neutrons to be made first and then come together to make helium. But technically it's not impossible. You have this big soup of quarks and gluons, and as it's cooling, it is possible for an entire helium atom to coalesce out of that soup without ever having been hydrogen.

00:28:53
Speaker 1: M And you can keep going right, like, maybe some carbon also was created spontaneously. Maybe even some uranium was created spontaneously in the Big Bang. Is that possible.

00:29:04
Speaker 3: It's possible. Now, uranium is unstable, so if you did make primordial uranium, it would have decayed, but you could have made like primordial lead, which is the heaviest stable element. Now we're talking about really really tiny possibilities. And the only reason we can't say it's totally impossible is because if the universe is really vast or even infinite, then anything that's super unlikely is gonna happen. And we want to give Trevor as accurate an answer as possible. And so it could be that there is an atom out there made of lead which was created during the Big Bang without ever having been hydrogen. But the overwhelming majority of stuff in the universe that's made of atoms almost certainly was hydrogen.

00:29:44
Speaker 4: First.

00:29:45
Speaker 1: The way you're saying there could have been one lead atom, but only one, like given the observable universe, but the universe that we can see. Do you actually have a number for your estimated probability of this happening or are you just kind of making it up in your head right now.

00:29:58
Speaker 3: No, I'm just saying it's possible that the is one. I mean, the probability of forming even helium directly out of those quarks is so astronomical I think I would bet against there being one in the observable universe. So now if you're going for a lead, yeah, I'm not going to take that bet either, but it is possible, so you can't rule it out.

00:30:16
Speaker 1: We are talking about the astronomical probabilities, all right, So then the answer is Daniel Wooden bet one. But it is still possible to create matter that was not hydrogen first.

00:30:27
Speaker 3: Yeah, exactly. And Trevor also asked this follow up question about like the nature of quantum particles. Can you think about them having a long history or this sort of a femarole, And this is a good philosophical question, you know, you could ask like when is a photon the same photon? If the photon bounces off of a wall, is it the same photon or was it absorbed and recreated, and that in the end is a philosophical question and sort of an arbitrary distinction. You know, the information in the universe flows through these particles and is preserved in those quantum states, whether you count it as the same particle or not. It's sort of like the question of whether the Star Trek transporter actually kills you and recreates you or transports you literally to another location. It's really more of a philosophical question than a physical one.

00:31:11
Speaker 1: I see, Trevor, I hate another question here in this question. He tried also to go recursive. Now is it still a question, Daniel? If it has two questions inside of it.

00:31:21
Speaker 3: That's a good question.

00:31:23
Speaker 1: Yeah, let's keep going. Now why is it a good question? All right? Well, Trevor, I think that answers your question. Thanks so much for sending that in. And now let's get to our third question, which is about the infinity of time time time. So let's dig into that. But first let's take another quick break. Or we're answering listening to questions here today, and our third question comes from I'll be.

00:32:00
Speaker 7: Hi, Daniel and Jorge. In any finite period of time being constrained by the laws of physics, finite extents in time or in space could never become infinite at least, I think, how does physics, then, given the proposed finite age of the universe, contend with the real possibility of an infinite universe? Would it have had to have been born infinite? If indeed it can't grow from finite to infinite size, and working backward from a finite or infinite size, how could that have grown from a universe that was infinitesmally small?

00:32:44
Speaker 1: Thank you all right? I feel like this question is also recursive in or at least it's giving me a bit of a headache here talking about the different infinities. I think what Abbi's asking is, do you need infinite time to make an infinite universe?

00:33:00
Speaker 3: Exactly? And I think obvious Struggling to reconcile two ideas that are out there in the sort of popular science universe. One is that the universe might be infinite, could go on forever and ever and ever, even beyond what we can see, So the full universe, beyond the observable universe could be infinite in extent. That's one idea, And the other is this conception of the Big Bang as the universe having started from a point that there was a tiny dot of stuff and everything flew out from that dot. That dot seems finite, and so I think Abby's wondering, well, how do you start with this finite dot then end up with infinite space filled with infinite stuff? That seems like a disconnect.

00:33:41
Speaker 1: Right, right, because I guess the way the Big Bang is usually percented, it does start with a dot, and a dot seems finite.

00:33:48
Speaker 3: Exactly, and there's a way to interpret that. It's being technically correct, but I think mostly it's misleading. People think of the Big Bang as this tiny dot, like smaller than an atom, containing all the matter in the universe, which then expands ended out into empty space, and people wonder like, well, how could that turn into something infinite? And the way that we actually think about the Big Bang is not in that sense at all. We think about it more in the way that we just described, And answer the last question. You start with potentially infinite space already filled with stuff, but there was no empty space back in the beginning, that everything was already filled. However much space there was, it was already filled with some hot, dense state, a state we can't explain. We don't understand where it came from. But the Big Bang describes the expansion of the universe from that point. So there's no empty space. Everything's already filled, and the Big Bang is not the explosion of stuff through that empty space, but the expansion of that space, which makes it colder and more dilute.

00:34:44
Speaker 6: Right.

00:34:44
Speaker 1: I think what you're trying to say is that, like we think of the Big Bang as a moment of creation, but you're saying that the Big Bang is not really when the universe was created. It's just when the universe expanded from being super compressed to being less compressed. The universe was there already and it was infinite.

00:35:02
Speaker 3: Yeah, exactly. And that's because we know there's a limitation to our theories. Like we can talk about quantum fields and all that stuff describing space, and that works up to a point, up to a certain density of the universe, beyond which our theories break down. It's at that point when everything is so dense that you can't really ignore gravity anymore. You need a theory of quantum gravity to describe the universe that is that dense. So before that, we don't even try to explain. So we start our history of the universe the first moment that we think our theories can describe, when the universe is super hot and super dense, but we think we can describe it used in quantum field theory. Before that, we have no idea, question mark, question mark, inflation, instantans, who knows, squiggly ons, whatever. But the history of the universe begins in the first moment we can describe, and the big Bang is the evolution of that universe, the expansion, the cooling and coalescing into particles, et cetera, et cetera.

00:35:54
Speaker 1: I think maybe what Auby is also trying to kind of grapple in their heads, is this idea of find time right, because a lot of physicists say that time started with the big Dang, possibly, and that there was no time before. If you sort of run the clock backwards, at some point, there was no time, and so what was the universe back then exactly?

00:36:15
Speaker 3: And that's extrapolating past that super dense point using just general relativity, saying well, what if general relativity is correct and that's the way time and space works, and we can ignore the unignorable quantum effects. That's what general relativity predicts. Predicts that time begins in the singularity of density. But that's sort of ridiculous extrapolation. We know that quantum theory needs to be accounted for there. So yeah, if you extrapolate general relativity beyond where we think it's relevant, then you get this prediction that time begins at some certain point, which is also difficult to grapple with. But that's not something we're confident doing because we know the theory breaks down.

00:36:51
Speaker 1: I see. So the answer is we don't know.

00:36:54
Speaker 3: The answer is we don't know, and we think it's possible that the universe began infinite, that that first moment, at least that we can describe the universe was already infinite, filled with an infinite amount of stuff that then expanded and cooled into a universe that was larger. Right, you can take an infinite universe and make it larger just by stretching it, so you can create new space everywhere in that universe, making it effectively larger and colder. So that's how we get to an infinite universe today, is that you start with an infinite universe. Abby's totally correct that if you start with a finite sized universe, you can't then have an infinite universe. Today, we don't know if the universe is infinite. We can only see a certain distance out there. We know the universe is huge and vast. It might be infinite beyond that horizon, or it might be that it's finite.

00:37:41
Speaker 1: Well, I think maybe Abby is also maybe posing the question like what happens if you take an infinite universe and you squish it down to an infinitely small size. Does it become then a finite universe? Because as we all remember from Calculus one, if you divide infinity by infinity, it depends, But one of the positive abilities is that you get a finite number.

00:38:02
Speaker 3: You get a finite number in the limit, right, which would take technically an infinite amount of time. The only way to go from a finite universe to an infinite universe is taking an infinite amount of time.

00:38:12
Speaker 1: But if you go backwards, are you saying it would take an infinite amount of time to compresent infinite universe an infinite.

00:38:19
Speaker 3: Amount exactly into a finite point?

00:38:21
Speaker 1: But you know, I think the universe is time right, like the universe not really doing anything else? Do universe do it?

00:38:27
Speaker 3: It's possible. I mean that state we talked about, that initial state that we can't explain. We know how far back that was. That was fourteen billion years ago. What happened before that? There could be an infinite amount of time before that, or there could be just five minutes. We don't know. Right, it's possible that deep in the infinite past, if it exists, there is a finite origin to the infinity of the current universe.

00:38:48
Speaker 1: Mmm. So I'll be sort of right. You can sort of go from a finite universe to an infinite universe if.

00:38:54
Speaker 3: You have infinite time. You have to assume infinity somewhere. You can't go from a finite universe to an infinite universe in finite time.

00:39:02
Speaker 1: But maybe the universe had infinite time.

00:39:04
Speaker 3: Maybe it did. We just don't know what the squigglyons were doing before that moment. We can't describe.

00:39:09
Speaker 1: Yeah, the bits on I think you mean.

00:39:12
Speaker 3: The university news.

00:39:15
Speaker 1: Yeah, the Albinos. We'll call them obinos in honor of Alby, who apparently sparked the revolution in physics starting today.

00:39:24
Speaker 3: Congratulations on your future Nobel prizes, infinite numbers of them.

00:39:27
Speaker 1: No, no, we get the Noble awesome congrati. But Abby just gets to be named. Yes, yes, let's be clear here, or at least I get it. I don't know if I'll share it with you.

00:39:37
Speaker 3: Well, I hope you have a nice tux.

00:39:40
Speaker 1: I have to buy one. I hope it doesn't cause it an infinite amount of money, though.

00:39:44
Speaker 3: Just get the T shirt tuxedo. I think that's probably fine for a cartoonist.

00:39:47
Speaker 1: Oh boy, I wonder how many physicists have been tempted to do that, you know, like if one of these hipster physicists that you see on TV, they're like, they get a Nobel price, but they go into talks or are they too cool for that?

00:40:00
Speaker 3: I bet there's like a Swedish sniper and ready to take them out just in case they try that.

00:40:03
Speaker 1: Oh jeez. All right, Well, I think that answers obvious question depends on your infinities, but also it sort of depends on maybe the true nature of the universe, whether infinities are allowed, whether quantum mechanics at some point breaks this idea of things being infinitely small.

00:40:25
Speaker 3: Real question is what happened before that hot dense state. The first thing that we can describe with our laws of physics, and in the end, it all comes down to quantum gravity, the biggest open question in modern physics. How do we reconcile gravity and quantum mechanics so we can describe a state denser that can be described with our quantum theory.

00:40:43
Speaker 1: All right, well, thanks to everyone who asked their questions here today. We hope you enjoyed that. Thanks for joining us.

00:40:53
Speaker 3: For more science and curiosity, come find us on social media where we answer questions and post videos on Twitter, Discorg, Insta and now TikTok. Thanks for listening and remember that Daniel and Jorge Explain the Universe is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.