Pod Insights Daniel and Kelly's Extraordinary Universe What broke the grand unified force in the early universe? About this episode Daniel and Kelly walk through the early history of the Universe to explain how forces can be unified, or broken.
See omnystudio.com/listener https://omnystudio.com/listener for privacy information.
Transcript 12,783 words · 7 speakers
Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.
0:00 Daniel Whiteson? This is an iHeart Podcast. Guaranteed Human.
0:04 Speaker 01 Granger knows if you're a procurement manager at an industrial manufacturing facility, you're balancing inventory and budget while sourcing critical supplies across the operation. Too much inventory? Costs climb. Too little? Production slows. Granger's $2 billion in on-hand inventory helps you get what you need, when you need it, so you can help keep budgets balanced and lines moving. Call 1-800-GRanger, click Granger.com, or just stop by. Granger, for the ones who get it done.
0:35 Speaker 02 Snoring, gasping for air during sleep, daytime sleepiness? I'm Shaquille O'Neal, and this shouldn't be anybody's experience. Ask your doctor about Zepbound Trisepotide, the first and only FDA-approved prescription medicine for moderate to severe obstructive sleep apnea in adults with obesity.
0:51 Speaker 03 Zepbound is a prescription medicine used with a reduced calorie diet and increased physical activity to help adults with moderate to severe obstructive sleep apnea (OSA) and obesity to improve their OSA. Zepbound is approved as a 2.5, 5, 7.5, 10, 12.5, or 15-milligram injection. Zepbound contains trisepotide and should not be used with other trisepotide-containing products or any GLP-1 receptor agonist medicines. It is not known if Zepbound is safe and effective for use in children. Don't share needles or pens, or reuse needles. Don't take if allergic to it, or if you or someone in your family had medullary thyroid cancer, or if you've had multiple endocrine neoplasia syndrome type 2. Tell your doctor if you get a lump or swelling in your neck. Stop Zepbound and call your doctor if you have severe stomach pain or a serious allergic reaction.
1:36 Speaker 03 Severe side effects may include inflamed pancreas or gallbladder problems. Tell your doctor if you experience vision changes before scheduled procedures with anesthesia, if you're nursing, pregnant, plant-to-be, or taking birth control pills. Taking Zepbound with a sulphonal urea or insulin may cause low blood sugar. Side effects include nausea, diarrhea, and vomiting, which can cause dehydration and worsen kidney problems.
1:58 Speaker 02 Talk to your doctor. Call 1-800-545-5979, or visit zepbound.lily.com.
2:05 Speaker 01 We all have routines. I'm Jabran, and with diabetes, mine was finger sticks. Sometimes, I skip them because they hurt. The Freestyle Libre 3CGM changed that. It gives me glucose insights without finger sticks. Learn more at freestylelibre.us.
2:21 Speaker 04 Finger sticks are required if your glucose alarms or readings do not match symptoms, or when you see check blood glucose symbol for the first 12 hours. The views expressed should not be used for medical diagnosis or treatment as a substitute for professional medical advice. Individual circumstances may vary. For prescription only. Safety info found at freestylelibre.us.
2:35 Speaker 05 My name is Jessa. One of the things I love the most about working for United Healthcare is that everybody matters. Every moment matters. There's a person behind every problem. I care because it's what I was put on this earth to do.
2:51 Speaker 06 I'm Ben, and I work at United Healthcare. I am just one piece of a larger puzzle, but every piece matters. It's more than just work. We want to make the healthcare system better for everyone. I care because I want to make a difference. That's what committed to care means to me.
3:13 Daniel Whiteson? Physicists talk a lot about what happened in the first moments of the universe. Non-physicists sometimes ask, "Why do you all care so much? Why should anyone care?" This question flabbergasts me. Of course, we should care. Who wouldn't want to know? It's the literal cosmological context of our lives. Knowing what happened in the early universe would be a huge clue in all sorts of late-night dorm room conversations about, "Why are we here?" And it could inform, you know, how we should live our lives. How is it possible, I wonder, for people to walk around not caring about the early universe, not wanting to know about the origin of the cosmos?
3:58 Daniel Whiteson? If you were expecting me at this point to drop some personal growth story where I came to realize that not everyone cares about these things, I'm going to disappoint you. I'm still totally flabbergasted if people aren't interested in the early universe. Because we think there are so many answers to the big questions waiting for us there. When the universe was hot and dense, it behaved differently. The forces were unified and things were harmonious, described by grand unified theory, which we hope has mathematical beauty enough to transcend its unfortunate acronym, GUT. As the universe cooled, these symmetries cracked and broke into the laws that we have today. On today's
4:43 Daniel Whiteson? episode, we're going to be digging into those first few moments, explaining how forces can be unified and what it means for them to break apart. We'll take a journey through time, space, energy, and ugly acronyms. Welcome to Daniel and Kelly's extraordinary acronymical universe.
5:15 Speaker 01 Hello, I'm Kelly Wiener Smith. I study parasites and space and GUT is an acronym in animal behavior as well, but for us it means giving up time.
5:26 Daniel Whiteson? Hi, I'm Daniel. I'm a particle physicist who also likes thinking about aliens and I'm in a hot competition to be vice provost for GUT research at the Weitzin Institute.
5:37 Speaker 01 Oh, but that means something totally di- that's not an acronym at all, though, right? That's just straight up guts. You're not- no one's giving up over there. There's no depressing giving up.
5:46 Daniel Whiteson? No, Katrina studies literal, actual guts and I study hypothetical, potential grand unified theories. And I feel like, you know, maybe that's more important. I don't know. We argue about it.
5:56 Speaker 01 No, you're wrong. You're wrong. Giving up time has to do with eating, though. It's about like, how long do you forage in a certain pack?
6:02 Daniel Whiteson? Before you decide that your payoff would be higher if you went to go forge in a different patch. Oh, I see. Because, you know, the cost of being in that patch and the amount of food available, etc. It's, it's actually very mathy. A lot of math goes into figuring out giving up time. But, uh, anyway. Well, maybe the grand unified theory all along was how we're going to unify all of our science into one acronym. Whoa. Yeah. I guess. The meta acronym. Yeah. I, yeah, I feel like it should be something funny. Maybe gut is not going to be it, but here's my question for you. So today we're talking a lot about the big bang or the BB.
6:39 Daniel Whiteson? The BB? Oh, no, that's terrible. Well, your, your outline says BB throughout. And so I assumed that was like a field thing. You're totally right. Is that just a Daniel laziness thing? Nobody ever pronounces that acronym, the BB. Nobody refers to the big bang as the BB. Although maybe now they will. And though I've written that many, many times, I've never even mentally thought of it out loud as like the BB. Hmm. All right, well, I am a real trendsetter and so I suspect from now on, when you go to conferences, it's going to be the BB. No. Said quickly, just like that. But so here's my question for you. So we, you know, we talk regularly about how we know what it was like, like at the
7:21 Daniel Whiteson? moment of the big bang and then moving forward, but we can't know what it was like before the big bang because we can only see what happened at the big bang and then afterwards. But what do you think it was like before the big bang? Because surely you have like smoked some banana peels and thought about that. And so what, like, if you had to guess, what, what would you guess? What is your like sleepy time dreaming? What is, what was it like before the BB? Yeah, well, great question. The pre BB. Yeah. That's a good question. You know, I really don't know, but I do have a mental image for placeholders. Okay. Like if I don't know, my brain conjures up this like black and gray fuzz where you can just make out the outlines of huge purple dragons. Really?
8:06 Daniel Whiteson? Which in my mind represent like the crazy unknown thing we might discover. Who knows? Like, you know, when we turn on the Large Hadron Collider, who knows what's going to come out? Maybe huge purple dragons. And obviously, I don't expect literal purple dragons, but just sort of like a stand in. And then my mind just sort of goes there visually also. So if I rewind past the Big Bang, I literally imagine a dark cosmos with purple dragons in it.
8:32 Speaker 01 I love that. Does that have anything to do with like, I think in maps, when we didn't know what there was, we used to write, here, there be dragons. Was that, no, that's not where that came from though?
8:42 Daniel Whiteson? If I was smarter and more literate, then I would claim that that was inspired by there be dragons. Yes. It's make me sound a lot smarter.
8:50 Speaker 01 Well, I could be totally wrong about that. And maybe that might be some like internet lore that I picked up somewhere, but, but I liked it. So it stuck. And, okay, that's very cool.
8:58 Daniel Whiteson? All right. Yeah. Well, there you go. A little insight into Daniel's banana peel brain.
9:02 Speaker 01 No, I don't have a brain that makes pictures quite as much as yours does, I think.
9:08 Daniel Whiteson? All right. So then in Kelly's brain, what's the pre BB look like?
9:13 Speaker 01 I haven't really thought about what the pre BB, I mean, I don't have as much like information to, but I guess you would say that you also don't have information to inform what the pre BB was like. So none of us do. And so, I don't know, maybe just pure darkness.
9:29 Daniel Whiteson? Hmm. Interesting. That's like the default state of the universe.
9:32 Speaker 01 Yeah. I don't know. I like the idea of dragons.
9:36 Daniel Whiteson? Well, let's dig into the episode and maybe at the end of it, we can check in with Kelly to see if it's changed her mental picture of the pre BB.
9:43 Speaker 01 Okay.
9:43 Daniel Whiteson? But today's episode is actually inspired by a listener who watched a YouTube video about the early universe and the grand unified force and how it broke into four other forces, didn't really understand it and wanted more details. Here's a question I got from Dilair Mustafa from New South Wales.
10:01 Speaker 01 Hi, Daniel and Kelly. My understanding is that after the Big Bang, there was one grand unified force. And then this force started breaking down to the four forces which we know now. My question is, what was there when this force was around in terms of energy and particles? Like, what was the form of energy? Was it in form of photon or whatever type of energy? And also what particles, boson or fermion and so on? And what caused this force to break down? And if you can explain what were the steps of this breakdown? What happened first and so on?
10:42 Speaker 01 And which particles or energies resulted from these transitions steps? And also what forces and particles and energy we have today? Thank you very much, Daniel and Kelly. There's a lot of questions in that question.
11:00 Daniel Whiteson? There are, and this happens a lot, that people watch a video or listen to some other podcast and they don't quite get it. And they write to us, they're like, what does this mean? And I'm not mad about that at all. I'm very glad that people are watching videos and listening to science podcasts. I'm also glad that they reach out when they don't get it, that they come to us because it means that they think we'll answer, because we do.
11:23 Speaker 01 Yes, and that's an honor, I think, to be, to be the person that people go to. And they're like, oh, I was still confused. Can you break this down even more? So, thank you for trusting us with your questions.
11:33 Daniel Whiteson? And this is a super fun topic and one I really did want to dig into because it's an opportunity to clear up, I think, a lot of misconceptions about what it means to unify forces and how things break in the universe and how the universe has changed over time and what that really means. And dig into the sort of philosophical underpinnings of effective theories, which I always want to talk about. But before we get there and before Kelly has to rein me in, I checked in with the extraordinaries to hear what they thought about this topic. I asked our cadre of volunteers, what broke the grand unified force in the early universe? If you enjoy hearing this segment and want to add your voice to it, please don't be shy. We would welcome you in this chorus.
12:15 Daniel Whiteson? Write to us to questions at danielandkelly.org. Here's what listeners had to say about what broke the grand unified force in the early universe. Which force are we talking about again? Dark energy. I think the overall energy dropped below a certain threshold
12:32 Speaker 06 and that's what broke it. I would say that the grand unified force broke itself in the same way that an egg breaks when the chicken cracks out of it. Something to do with the balance between matter and antimatter.
12:43 Daniel Whiteson? As this is Daniel Kelly's extraordinarily fecal at times universe, it might be poo.
12:50 Speaker 06 Did a cat knock it off the shelf? I think the emergence of light. Chuck Norris.
12:55 Speaker 01 expanded, no more unified force. Does it have anything to do with Planck's constant? We don't have a grand unified theory yet. Some kind of symmetry violation that only manifests below a certain energy threshold. It wasn't me, honest. Oh, man, Chuck Norris, rest in peace. I gotta be honest, I don't know anything about Chuck Norris, the man. But I knew a lot about Chuck Norris, the myth. I really loved those Chuck Norris jokes at like some point in my life. And Chuck Norris is no more.
13:29 Daniel Whiteson? He lives on forever in you, Kelly.
13:31 Speaker 01 Uh, okay.
13:33 Daniel Whiteson? That make you uncomfortable?
13:34 Speaker 01 A little, a little. If that's the case, I probably should learn a little bit more about the man, but I enjoyed the jokes.
13:43 Daniel Whiteson? Or maybe some martial arts.
13:44 Speaker 01 Yeah.
13:44 Daniel Whiteson? But we're not talking about Chuck Norris mostly today. We're talking about the universe and we're talking about how the universe changes over time. And before we dig into what are the fundamental forces and how do they unify high energy and then walking through the timeline of the very early universe to explain all of that. I want to spend a minute on the big picture of what it means to have the laws of physics change. Because that's what we're talking about. The grand unified force broke into other forces. And what does it mean to have one set of forces and then later another set of forces? How does the universe change its forces? Is that going to happen in the future? What's going on here? And so I want to remind everybody that there might be some fundamental theory of the universe that describes everything that's happening and controls everything that's happening.
14:29 Daniel Whiteson? We don't know what that is. We don't have it, right? It's not something we possess now. We can't write it down. And even if we did, even if like advanced aliens showed up and they told us, here's the equation of the universe. It might not be very useful, right? The way like even particle physics today, which describes a lot of the quantum mechanical details of our universe is not all that useful. You don't use it to predict how a ball flies across your backyard or whether Tesla stock is going to go up or down, or whether this hurricane is going to be your left or right. It's not very useful because it's very. Connected from those level of details. You need to simulate like 10 to the 37 electrons to predict what's going to happen in that hurricane.
15:13 Daniel Whiteson? It's it's not a useful theory. So number one, we don't have it. And number two, even if we had it, it wouldn't be the kind of thing we needed to describe the universe we experience. Does that make sense? It does. So this sort of sounded familiar. And so is this what we were talking about with Ethan Segal? When we were talking about single unified theories in physics? When we had him on the show on October 15th, 2025? Oh, my gosh, what a photographic memory. No, no, no, no, looked it up, looked it up.
15:42 Daniel Whiteson? Looked it up in advance, even look at that doing your homework. Yes, exactly. We were talking about whether there is an underlying theory or not. Because we don't have that theory. What we do have are what we call effective theories that are useful in various situations. So we don't think and don't pretend our fundamental theories of the universe. They're approximate theories that help us out in certain situations. The way, for example, Newton's laws can predict what happens when you throw a ball across your backyard. Nobody thinks Newton's laws are written in the cosmos, right? That they're fundamental in some way, but they work. They're effective. They're an approximate description of physics at this scale, and they work. But they work within boundaries. If your ball goes near the speed of light, it doesn't really work anymore.
16:27 Daniel Whiteson? If your ball goes near a black hole, it doesn't really work anymore. And so rather than having a deep fundamental theory that isn't useful for anything. We have a patchwork of effective theories that are each useful for something. And I think maybe an illustrative way to think about this is to think about the phases of water. Like we have a theory that describes how water behaves when it's a vapor, the ideal gas law. We have a different theory that describes how water behaves when it's a fluid, right? Fluid dynamics, very different set of equations, right? They both describe water. It's the same stuff, right? Probably in the core of the universe, there are fundamental laws that are determining what's happening to water molecules in both scenarios. But when you zoom out, you end up with very different effective laws.
17:12 Daniel Whiteson? And if you freeze it, you get an even different set of effective. Laws, right? So what's happening there? The universe is not changing the rules. We are changing how we describe the universe because we want a useful theory. And the useful theory is different in each situation. Frozen water, liquid water, gaseous water. Does this reflect that we're missing something? And if we were like smarter, we could have an equation that would describe what's happening in all of those situations? Or is this just the nature of the universe? There are like discontinuities and you need different equations to describe things at different times? Or yeah, what do you, what do you think's going on there? Yeah, we don't know, right?
17:55 Daniel Whiteson? We don't know if there really is a deep truth. It could be that all there is are these effective theories, these approximate patchworks that maybe come together or maybe there are gaps between them. We don't know. Ethan Segal believes strongly that there is a fundamental theory and that all of these effective theories are just approximate versions of it. And he might be right, but we don't know. And even if we did, we probably wouldn't use it, right? Because it wouldn't be very useful. Like if I could tell you that the universe is made out of squiglyons right now, doesn't mean I could calculate the flow of sewage through pipes using squiglyon physics, right? Because it would take like enormous number of calculations and be dependent on all these details.
18:36 Daniel Whiteson? I would probably still use Bernoulli's equation or whatever fluid dynamics people use, right? Because that's effective, that's very useful. So these effective theories are very powerful. And as the situation changes, as the phase changes in water, you change your effective theory. And this, I think it really helps you understand what's going on in physics. A lot of the time that we summarize a lot of the microscopic details we don't know, often in terms of one like unexplained number. I'll give you another example. We often talk about light flowing through material and moving at slower than the speed of light, right? People say light moves through a vacuum at the speed of light, but through glass, it's a little bit slower. And through other materials, it's at a different speed.
19:21 Daniel Whiteson? And there's a number, the index of refraction that tells you how light bends at all. Also the speed of light through that material. And that's confusing to people because they're like, how do you slow down a photon? What's going on? And that's an example of an effective theory. It's not that photons are slowing down and moving it slower than the speed of light. Instead, it's as if light was moving slower. It's not that that's what's happening, but if you describe it that way, all the predictions come out. So if you really want to zoom in on the microscopic details, you see light never moves as slower than the speed of light. It like zaps between atom and atom and is an excited wave of electrons that move through the material. It's very, very complicated. The microphysics of light moving through material, super duper complicated.
20:03 Daniel Whiteson? If you don't know how that works, or you don't care, you can just zoom out and say, it's kind of like light moves a little bit slower than the speed of light. And all the numbers work out. All those microphysics get wrapped up in this one number you can measure. The index of refraction. It's the same thing for like friction. Friction is super duper complicated. You have two surfaces, they're sliding over each other. How they interact depends on lots of details. You can sum it all up in one number. It's called the coefficient of friction. Point seven or point four two or whatever tells you how two things slide across each other. If you don't know or care about the microphysics. So often we have these effective theories where a lot of the high end details are bundled up into a single number we just measure.
20:47 Daniel Whiteson? That encapsulates all those details we either don't know or don't care about. So as we move through the timeline of the universe and we talk about, we're using this theory now. We have two forces now, we have four forces. What was changing was not how the universe works. There's still that fundamental law, perhaps that Ethan Segal believes in. What is changing is how we effectively describe the universe because the phase of the universe changes. The universe goes from very hot to very cold. And as it goes through those temperature changes, the effective laws change. What's useful, what's practical for describing the universe changes. I'm going to go ahead and admit that I was moderately quiet during the conversation that you and Ethan had because I was,
21:30 Daniel Whiteson? you know, not, I didn't have much to add, let's say, but, but I thought that I remembered Ethan.
21:34 Speaker 01 arguing that there was like a unified thing that was happening at the early universe, but then something about like the energy state went down over time. And then the unified thing broke down as the energy changed phase or there was less of it. And so what was he saying? And how does it differ from what you believe? Cause I remembered you two didn't, didn't quite agree on something.
22:02 Daniel Whiteson? Yeah, good memory. There's something else really cool that happens. As you increase the temperature of the universe, you go to hotter and hotter phases of the universe. Then the differences between the various effective theories tend to sort of wash out. They become irrelevant, sort of like, you know, the way the shape of a mountain matters a lot. If you're climbing over it, but if you're flying over it, it doesn't really matter so much.
22:25 Speaker 01 Okay.
22:25 Daniel Whiteson? And so we'll go into detail about exactly that. But I think Ethan and I had a different concept of what it meant to unify physics. He was thinking about the very early universe, when things are very hot. Can you ignore the details between all the forces in your effective theory? And I was thinking about whether there's an underlying theory even now that does unify everything, but maybe isn't a useful effective theory.
22:49 Speaker 01 Got it. All right, let's take a break. And when we get back, let's remind ourselves what the five forces are today and talk about how we might unify them.
23:09 Speaker 02 Snoring, gasping for air during sleep, daytime sleepiness. I'm Shaquille O'Neal, and this shouldn't be anybody's experience. Ask your doctor about Zepbound terzipatide, the first and only FDA approved prescription medicine for moderate to severe obstructive sleep apnea in adults with obesity.
23:25 Speaker 03 Zepbound is a prescription medicine used with a reduced calorie diet and increased physical activity to help adults with moderate to severe obstructive sleep apnea, OSA, and obesity to improve their OSA. Zepbound is approved as a 2.5, 5, 7.5, 10, 12.5, or 15-milligram injection. Zepbound contains trisepotide and should not be used with other trisepotide-containing products or any GLP-1 receptor agonist medicines. It is not known if Zepbound is safe and effective for use in children. Don't share needles or pens, or reuse needles. Don't take if allergic to it, or if you or someone in your family had medullary thyroid cancer, or if you've had multiple endocrine neoplasia syndrome type 2. Tell your doctor if you get a lump or swelling in your neck. Stop Zepbound and call your doctor if you have severe stomach pain or a serious allergic
24:10 Speaker 03 reaction. Severe side effects may include inflamed pancreas or gallbladder problems. Tell your doctor if you experience vision changes before scheduled procedures with anesthesia, if you're nursing, pregnant, plant-to-be, or taking birth control pills. Taking Zepbound with a sulfonylurea or insulin may cause low blood sugar. Side effects include nausea, diarrhea, and vomiting, which can cause dehydration and worsen kidney problems.
24:32 Speaker 02 Talk to your doctor. Call 1-800-545-5979 or visit zepbound.lily.com.
24:39 Speaker 04 Cash Flow Crunch? OnDeck's small business line of credit gives your business immediate access to funds up to $200,000 right when you need it. Cover seasonal dips, manage payroll, restock inventory, or tackle unexpected expenses without missing a beat. With flexible draws, transparent pricing, and control over repayment, get funded quickly and confidently. Apply today at ondeck.com. Funds could be available as soon as tomorrow. Depending on certain loan attributes, your business loan may be issued by OnDeck or Celtic Bank. OnDeck does not lend in North Dakota. All loans and amounts subject to lender approval.
25:09 Speaker 06 Hey, it's Niall Rogers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything.
25:26 Speaker 06 This week, I'm joined by my friend, John Ledge. How does music actually enter your mind?
25:33 Speaker 01 I'm not sure why or how the music comes to me, but I think people who love music and write music, our brains are just filled with music. Like, we have listened to so much music. We've been a part of so much music. I think of the story that I want to tell, the mood that I want to create with the music, start playing chords, see where they lead me.
25:54 Speaker 06 Sometimes, I'm just not even thinking about music, right? And I hear this little thing, and I go, oh, that could be this.
26:04 Speaker 01 You know, you just have to be ready for when the inspiration hits.
26:08 Speaker 06 Yeah. Experience before the moment. A Lincoln original series on the iHeart Radio app, YouTube, or wherever you get your podcasts.
26:28 Speaker 01 All right, we're back. And Daniel, it's Physics 101. What are the five forces that we've recognized today?
26:35 Daniel Whiteson? All right, this is a lot of fun. And already, people will disagree because some people say there aren't five forces. There are four forces, there are three forces, whatever. Let's start with the broadest categorization and say electricity, right? That's the thing that powers your laptop. And then magnetism, which we'll count separately and then unify later. And magnetism, of course, is refrigerator magnets and load stones and compasses and stuff like that. Then there's the weak nuclear force, right? Which is responsible for radioactive decay. It doesn't play a big role in our lives, but it's there and important. Then there's this strong nuclear force. That's very important for fusion and holding the nucleus together.
27:17 Daniel Whiteson? So those are the four quantum fundamental forces. And then there's gravity, which seems like a force to us and I think deserves to be included on this list because we hope to unify it with these four eventually. But that's the starting point. Sort of historically, humans have been poking around and noticing stuff happen. And we built up this sort of phenomenological history like that we see this kind of stuff. Let's call it one thing. We see that kind of stuff. Let's call it one thing. We started out with basically five fundamental forces. And so first, we can talk about how we unify them as we go backwards in time. And then in the next segment, let's walk through the history of the early universe and see them breaking as time goes forwards.
27:59 Speaker 01 Okay, real quick before we do that, do we think that we've got all of the forces that matter? Or because we don't understand dark matter?
28:10 Speaker 01 Or is it dark energy? Which one do we not understand? Both?
28:12 Daniel Whiteson? Neither. We don't understand either of them.
28:14 Speaker 01 Okay, are there, is it possible that there's more forces we're going to have to unify? Once we understand things better and these are just the five we're working with right now?
28:21 Daniel Whiteson? Oh, yes, and I hope so.
28:22 Speaker 01 Okay.
28:23 Daniel Whiteson? There could definitely be more forces involved in the dark sector. If there are lots of dark particles out there, they could interact with each other using new dark forces. There could be dark photons and dark Ws and dark Zs and all sorts of stuff. There could be a dark strong force and dark energy could be the product of another force. We don't know about it either. It's really a big question mark. It's basically flying purple dragons where physics is concerned. So yes, these are the ones we know today. Good point.
28:49 Speaker 01 And I love the idea of a dark sector. I feel like that needs to be in someone's book somewhere, but okay, so how do we unify them?
28:56 Daniel Whiteson? Yeah, so what we do is we notice that forces have things in common, right? But that doesn't mean they have to be the same. When we unify forces, we don't say electricity and magnetism are the same thing. What we do is we notice that they're two sides of a coherent whole, that they make more sense to click together than to keep track of them separately.
29:19 Speaker 01 Okay.
29:19 Daniel Whiteson? Like if you have literally two sides of a coin and you never noticed that heads and tails are related to each other. And you kept track of like heads and tails separately. And somebody told you, oh, did you realize that heads and tails are literally two sides of the same coin? That's where the expression comes from, right? It's much simpler because then you notice patterns like you can only see heads or tails. You can't see them at the same time, right? There's a relationship between them. If you add up the number of heads and tails. Tails, you get the number of flips you made, for example, right? So that doesn't require heads and tails to be the same thing. It requires them to be two parts of a larger whole. It's the same with like elephants. If you study elephant trunks and you study elephant tails and you don't think about the relationship between them,
30:04 Daniel Whiteson? you're missing out on the bigger picture. And your theory of elephant tails and trunks is not nearly as good as a unified theory of elephants that includes tails and trunks, right? So again, that's not saying tails and trunks are the same. It's saying that they're part of a larger whole.
30:20 Speaker 01 Got it. Yeah, you don't want to miss the whole elephant because it could squish you.
30:26 Daniel Whiteson? That's right. And we made a lot of progress early on in finding connections between the electricity and magnetism with Maxwell. There were these different observations of electricity and magnetism, and people had the various laws about it. Gauss's law, Ampere's law, et cetera. And Maxwell put together the four laws that related these things. And he saw a bunch of symmetries here. And he noted that the equations were very similar from the magnetic and electrical points of view. Basically, you could swap the electric fields and the magnetic fields in the equations and they wouldn't change. There was a symmetry there, right? That they were playing like the same role, asterisk, right? Almost.
31:07 Daniel Whiteson? He actually noticed that there was a gap, that that symmetry almost worked. And he wanted it to work. He like, oh, this would be so much prettier if it did work. So he penciled in the missing term that would be needed to provide this symmetry. There was no evidence for this term in the universe yet. He just said, hmm, boy, this would be more symmetric if it was there. And then he went out and looked for it and found it. That's displacement current. And so that shows you like, wow, there really is some symmetry in the universe, you know? Following mathematical symmetries leads you to physical discoveries. I love that. And so we know now that electricity and magnetism have a very close relationship, you know?
31:48 Daniel Whiteson? If you have electric charges and they move, that gives you magnetic fields. Or if you have magnetic fields that change, that can generate electric fields. So the two are very closely coupled. One can make the other one.
32:01 Speaker 01 Okay, but sometimes.
32:05 Speaker 01 The universe has mathematical symmetry and other times it doesn't.
32:09 Daniel Whiteson? Yes.
32:10 Speaker 01 So it's nice that it's here, but then we find that like water needs different equations for different phases and that doesn't feel very satisfactory. And so I guess I'd like a whole episode on when you should expect the world to be beautiful and symmetrical and when you shouldn't. And I'm guessing the answer is we don't know.
32:27 Daniel Whiteson? Yeah, well, even within electricity magnetism, the universe seems to reject perfect symmetries because you can't actually just swap electric fields and magnetic fields in Maxwell's equations because they have a really big difference. And that is that we have sources of electric fields, like particles with charges are sources of electric fields, right? An electron just sitting there makes an electric field. But there is no such source of a magnetic field. Magnetic fields only come from charges in motion. There's no like equivalent of the electron, no magnetron, or we call it particles as a magnetic monopole. So one of Maxwell's equations
33:09 Daniel Whiteson? has a zero in it to reflect the fact that there are no sources of magnetic fields. And another one has a non-zero to count the number of electric charges. So there is a fundamental difference there between electricity and magnetism. So they don't have to be identical. They just have to play nicely together.
33:26 Speaker 01 Okay, so they're linked, but they're not like a gradient from one to the other.
33:30 Daniel Whiteson? That's right. Exactly. Though there is some evidence that the dotted line we draw between them is a little bit arbitrary, because for example, in a given situation, whether or not there is a magnetic field depends on who's looking at it. Like if you have an electron and you're holding it in your hand, it makes an electric field, but no magnetic field. If I'm driving by in the highway at 100 miles an hour, I look at that electron, I see that as a charge in motion because it has a velocity relative to me. Charges in motion make magnetic fields. So my compass would measure a magnetic field from your electron. Your compass would measure no magnetic field. Is the magnetic field there or not? It's frame dependent,
34:13 Daniel Whiteson? it's observer dependent. So where you draw that dotted line depends on the observer, which is a strong argument that it doesn't make sense to account for these things separately, right? These things really are deeply linked.
34:26 Speaker 01 And that is why you say that they're linked, but you said there's five charges and you gave them separate count. Because they're linked, but they're different.
34:35 Daniel Whiteson? They are different and historically they were separate and then we brought them together. And there's a really powerful lesson in how we brought them together. Because another factor in electricity and magnetism is the strength of the force. Like if you're just sitting around at low speeds, electricity is much more powerful than magnetism. There's a law, the Lorentz force law, that tells you the force on a particle based on the electric field and the magnetic field. And the magnetic field is another factor in it. It's velocity, right? If there's no velocity, there's no force from a magnetic field.
35:08 Speaker 01 Okay, yeah, that makes sense because you said if you got to be moving in that prior example.
35:14 Daniel Whiteson? But what happens if you're moving at the speed of light? If you're moving at the speed of light, that velocity term, we write the speed of light as speed equals one. And so now the two things are totally equal. So magnetic fields are much weaker at low speeds, but at high speeds, they become just as powerful as electric fields. So at very high speeds, at very high temperatures, if you have a gas of particles whose particles are moving near the speed of light, the magnetic fields are equally as powerful as the electric fields. This is the kind of thing we mean by unification at high energies. At high energies, the differences between electric and magnetic fields start to wash out and become less important.
35:54 Speaker 01 Are we going to find that at all of our forces at high energy, they become the same?
35:59 Daniel Whiteson? That's the trend. It's very tantalizing. It's the kind of thing that make particle physics feel like it's possible to unify all the forces. Definitely happens here and it happens every time we unify a force, we find that it happens at higher energies.
36:13 Speaker 01 Okay, well, then let's jump to the weak and the strong force then.
36:16 Daniel Whiteson? Exactly. So we have electromagnetism, it's unified. And the particle that mediates electromagnetism is the photon, right? There's a photon field, the electromagnetic field, right? And we did that by putting electricity and magnetism into a single framework. Well, it turns out you can do the same with electromagnetism and the weak force. You can put those into a larger mathematical framework that in the same way makes a lot more sense. To keep track of and to think about like rotations and velocity dependence. It all works really, really well and explains a lot. But again, it doesn't work perfectly. There are still differences between electromagnetism and the weak force. And the most important one being the weak force is really weak.
37:00 Daniel Whiteson? It's weak because the particles that carry it, the W and the Z are really, really massive. Like the W and the Z weigh 80 and 90 times the mass of a proton, whereas the photon is massless. Okay. So the photon can fly forever through the universe, whereas the W and the Z are very short range because of their mass. So it's very weak force. So this is a symmetry between electromagnetism and the weak force, but it's a broken symmetry. All right. So what do we do to the weak force to make the mass not matter? We crank up the energy because the mass of the W and the Z only matter if you don't have a lot of energy around. If everything has a huge amount of energy, the fact that one of them has some mass doesn't matter anymore.
37:44 Daniel Whiteson? At the speed of light, the mass of these particles doesn't matter. So if you crank up the energy, then the weak force becomes stronger. It becomes just as strong as electricity and as magnetism. And those three strands all unify into one beautiful theory called the electro weak theory, which unifies electricity and magnetism. He uses group theory, which French mathematical nerds invented 100 years earlier just because they were having fun with numbers. Yeah, nerds. And it turned out to be, yeah, it turned out to be foundational in building our modern understanding of the universe. Another reason why you should give nerds money and leave them alone. Amen. And this all works really well, but you know, one obstacle is like, well, why is
38:28 Daniel Whiteson? the weak force different than the other forces? And that's the Higgs boson. Peter Higgs was like, how can you put these things together, but also break that symmetry? You gotta build the symmetry and then break it. So the Higgs boson is the thing that breaks the symmetry. It interacts with the W and the Z bosons and gives them mass, but doesn't interact with a photon, so leaves it massless. So not Only can we unify electricity and magnetism into one force that's beautiful and wonderful and high energies, they all act the same. We can also explain how at low energies, they are different.
39:04 Speaker 01 And the reason you have to be able to do both of these things is because we're pretty convinced at the big bang, all of the forces were the same. And we know that now there are situations where they're clearly doing different things. And so we need to be able to explain how both of those things can happen. Is that right?
39:24 Daniel Whiteson? A plus, Kelly. That's right. We live in a cold universe where things don't have the energy to fly near the speed of light. And so these differences matter. The weak force is measurably weaker than electricity and magnetism today, right now. But we do think in the early universe, it had more energy and it was able to ignore essentially the Higgs field. It didn't really matter. Because yeah, you get a little bit of mass, but who cares? You know, it's like giving a speeding ticket to a billionaire, right?
39:50 Speaker 01 No, those billionaires.
39:52 Daniel Whiteson? It's not gonna slow them down.
39:53 Speaker 01 Shake my fist. They're always going too fast. All right.
39:57 Daniel Whiteson? So things are going great, right? We were using group theory and mathematics to unify these things. As we crank up the temperature, things seem to unify beautifully. It's amazing. So let's get to the strong force. And here we're stuck.
40:10 Speaker 01 Oh.
40:11 Daniel Whiteson? We would love to unify the strong force into some grand unified theory of physics that brings together all of our quantum theories, but nobody's been able to make it work so far. This is a target of physicists for decades and decades, even putting aside gravity, right? We haven't even gotten to gravity yet. We don't know how to unify the strong force with the electro weak force. So we really only have two quantum forces at this point, electro weak and the strong force. And we would love to stick them together.
40:42 Speaker 01 And I don't want to make light of the suffering of physicists, but I'm just gonna note that electro weak appears to be abbreviated as E U and grand unified theory appears to be abbreviated as GUTS. And so your notes say we can't.
40:56 Daniel Whiteson? And not yet unify ew into gut. And so that's the kind of problem you guys are working on right now. Maybe somebody needs to come up with like a ble theory. That's right. Or like a vomit theory or something. And then the dragons can get cleared away.
41:12 Daniel Whiteson? The theory of dragon vomit is going to bring this all together. That's right. Good luck. And so there are obstacles here and one obstacle is that what happens when you turn up the energy? Then the strength of these forces changes. So all these forces have a strength that depends on the energy. And with electricity and magnetism, as you crank up the energy, the two come together, they're the same strength. And the weak force also merges together into one single strength. Really beautiful. As you crank up the energy, the strong force also changes, but it doesn't seem to grow together with the electro weak force. It's like a parallel line. It's not coming together. So that made people wonder like, hmm, is there something missing? And, you know, we've talked a lot of times on the show about the theory of supersymmetry.
41:57 Daniel Whiteson? It's a theory that suggests that for every particle, there's a new kind of mirror particle called the super particle. And it was created for other reasons to explain why the Higgs mass is so small, which is a mystery we don't understand. And it's also this like beautiful example of symmetry and the math nerds love it and they would love for it to be true in the universe. We've never seen any evidence of it, but if you add supersymmetry to the theory, then as you crank up the temperature, these forces do grow together. Oh. So it's like, maybe we have a missing piece. Oh, there's a piece over here that people invented for other reasons. If we stick it in, boom, then at high temperatures, everything comes together. That's amazing. Wouldn't that be beautiful?
42:40 Daniel Whiteson? That was a real motivating factor for people believing in supersymmetry. It felt like a huge clue. Unfortunately, we turned on the Large Hadron Collider and we didn't see supersymmetry. So yeah, that would have been nice. But for now, we don't know how to unify the strong force with the electro weak force. It might happen. It might be then the universe, something happened to bring these together, but we don't know how. And so we can theorize about a gut theory, a grand unified theory, but we don't know yet what that would look like. But looking ahead to when we do, what will the acronym be? Will it be ew?
43:17 Speaker 01 Electro weak, strong ooze.
43:21 Daniel Whiteson? Ooze, I think is going to be a strong contender.
43:24 Speaker 01 It's important to figure this out. Or so, strong electro weak. I don't know. All right. Anyway, we can move on, I guess, to more important things. And if I am remembering our list of five correctly, the last one is gravity that we haven't got to yet.
43:38 Daniel Whiteson? Exactly. And this one is even harder because, you know, unifying the strong force with electro weak is challenging because they look different and the details are different, but at least they're both quantum forces. You know, there are fields involved, there's momentum propagating through those fields, all that stuff. Gravity is a real head scratcher because it's a classical theory. You know, Einstein tells us that mass bends space and that space tells mass how to move, but it requires like mass to have a location and have a classical trajectory to always have a place and a time where it is and to go from here to there by going through space from here to there. And quantum objects don't behave like that. So we just don't know how to interface it with gravity. The search for quantum gravity is like, you know, the
44:22 Daniel Whiteson? most frustrating and exciting and terrifying and challenging thing happening in physics in the last hundred years. We talked about a lot of times on the show, if you could unify a gut theory with gravity, you'd have a theory of everything. So you'd have a toe and then you could make the theory called the toe ooze, I guess.
44:42 Speaker 01 I've already lost. What does toe stand for again?
44:45 Daniel Whiteson? Theory of everything.
44:46 Speaker 01 Theory of everything. Got it. Got. And how is that different than the grand unified theory?
44:50 Daniel Whiteson? Grand unified theory doesn't include gravity. So grand unified theory is electro weak plus strong.
44:55 Speaker 01 Okay.
44:56 Daniel Whiteson? And if you want to add gravity, that's a theory of everything.
44:58 Speaker 01 Got it. Got it. Okay. So gravity is the queen of the purple dragons.
45:04 Daniel Whiteson? Exactly. So force unification is very exciting and promising. Electromagnetism unified beautifully. The weak force added beautifully. Lots of Nobel prizes won. Beyond that is speculative. So grand unified theory that includes the strong force speculative. Quantum gravity that includes everything, a theory of everything, still very speculative, but we're hopeful. Maybe we'll figure it out.
45:27 Speaker 01 Okay. And we need to figure it out to really understand the big bang. Is that fair to say?
45:34 Daniel Whiteson? Yeah, I think so.
45:35 Speaker 01 Okay. All right. Then let's take a break. And when we get back, we're going to sort of go through the timeline of the universe to try to understand how this all played out. So we're going to play it all going forward.
45:53 Speaker 02 Snoring, gasping for air during sleep, daytime sleepiness? I'm Shaquille O'Neal and this shouldn't be anybody's experience. Ask your doctor about Zepbound Trisepotide, the first and only FDA-approved prescription medicine for moderate to severe obstructive sleep apnea in adults with obesity.
46:09 Speaker 03 Zepbound is a prescription medicine used with a reduced calorie diet and increased physical activity to help adults with moderate to severe obstructive sleep apnea, OSA, and obesity to improve their OSA. Zepbound is approved as a 2.5, 5, 7.5, 10, 12.5, or 15-milligram injection. Zepbound contains trisepotide and should not be used with other trisepotide-containing products or any GLP-1 receptor agonist medicines. It is not known if Zepbound is safe and effective for use in children. Don't share needles or pens, or reuse needles. Don't take if allergic to it, or if you or someone in your family had medullary thyroid cancer, or if you've had multiple endocrine neoplasia syndrome type 2. Tell your doctor if you get a lump or swelling in your neck. Stop Zepbound and call your doctor if you have severe stomach pain or a serious allergic reaction.
46:54 Speaker 03 Severe side effects may include inflamed pancreas or gallbladder problems. Tell your doctor if you experience vision changes before scheduled procedures with anesthesia, if you're nursing, pregnant, plant-to-be, or taking birth control pills. Taking Zepbound with a sulfonylurea or insulin may cause low blood sugar. Side effects include nausea, diarrhea, and vomiting, which can cause dehydration and worsen kidney problems.
47:16 Speaker 02 Talk to your doctor. Call 1-800-545-5979, or visit zepbound.lily.com.
47:23 Speaker 05 OnDeck is built to back small businesses, like yours. Whether you're buying equipment, expanding your team, or bridging cash flow gaps, OnDeck's loans up to $400,000 help make it happen fast. Rated A+ by the Better Business Bureau and earning thousands of 5-star TrustPilot reviews, OnDeck delivers funding you can count on. Apply in minutes at ondeck.com. Depending on certain loan attributes, your business loan may be issued by OnDeck or Celtic Bank. On Deck does not lend in North Dakota. All loans and amount subject to lender approval.
47:53 Speaker 06 Hey, it's Niall Rogers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything. This week, I'm joined by my friend, John Legend. What still makes you just sit down at the piano?
48:16 Speaker 01 If you sat down at nine AM and then at noon, you had a full song that you recorded and put in your voice recorder or you recorded at your studio, you just created something brand new that didn't exist when you woke up. Yes. What a beautiful feeling it is. I'm always excited to write something new. I've been writing for Broadway, which has been a new challenge with new collaborators and amazing performers who are triple threats, who can sing and dance and act and do all these amazing things. And I want to keep feeling that. And so that means not resting on my laurels, going out there and continuing to create something new.
48:51 Speaker 06 Experience Before the Moment, a Lincoln original series on the iHeart Radio app, YouTube, or wherever you get your podcasts.
49:11 Speaker 01 We're back and Daniel's gonna start with the Big Bang and take us forward and tell us about how these forces split up? Question mark.
49:19 Daniel Whiteson? Exactly. So we've been telling the story sort of backwards. We've been talking about taking the current universe at very low temperature, everything very cold, and heating it up to unify things. But time flows forwards, right? And so let's instead tell the story forwards also because that's the only chance we have to potentially maybe answer Delair's question, which was the whole point of this podcast. And so we're going to talk about the timeline of the early universe and we're going to use some crazy numbers to talk about time. And so what do these times mean? Remember that we don't have a lot of data for these very early moments. You mentioned at the top of the podcast, how we've like seen the Big Bang. We've actually only seen back to like 380,000 years after the Big Bang.
50:02 Speaker 01 Oh, that's right.
50:03 Daniel Whiteson? That's when photons were made.
50:05 Speaker 01 Yeah, okay.
50:05 Daniel Whiteson? So a lot of this stuff is speculative, but essentially, you take our current model of the universe, expanding and run it backwards to predict what would have happened deep, deep in early history. So let's go as far back as we can. If you run the clock back 13.8 billion years, you get to a place where you would need quantum gravity to continue. Like, we don't know how to predict what would happen because quantum mechanics is relevant and gravity is relevant. And so we call this time before the Planck time, because Planck is one of the grandfathers of quantum physics, or this is the Planck epoch. So before 10 to the minus 43 seconds in the universe. You can't go all the way back to t equals zero because we don't know how to do that, right?
50:48 Daniel Whiteson? Like, general relativity predicts a singularity. Quantum mechanics says you can't have that. So like, how do you even get to t equals zero? So before 10 to the minus 43 seconds, we say that's the Planck epoch. And the laws that are involved are some theory of everything, some quantum gravity that we don't know. It's all the forces all unified.
51:09 Speaker 01 So it's 0.4301 seconds before... Okay, all right. So we're really close to zero and all the forces need to be unified. So we don't know what's going on, but that's what we need to get.
51:25 Daniel Whiteson? That's right. And Delair also asked, like, what is the content of the universe at every moment here? Which I think is a really fun question. And at this early point in the universe, it's not meaningful to talk about particles because we don't think of the universe as filled with quantum fields. I remember here, we're always talking effective theories, right? What is a useful way to describe the universe? And to talk about particles, you need energy in quantum fields to be a useful description of the universe. And we don't know what quantum gravity will look like. Like, maybe it gets rid of quantum fields. Maybe it has something completely different. It's totally new and it tells a different story about the universe. So we can't even talk about like what particles were around because particles are excitations in a quantum field and we don't know if those are going to be part of the theory.
52:09 Daniel Whiteson? We don't have the theory at all. So we don't know what effective descriptions are going to emerge. We don't know what the fundamental theory is. We don't know what the like useful calculational tools are. We can't even really tell you.
52:21 Speaker 01 Wow.
52:22 Daniel Whiteson? Okay, but exciting. Big question mark, big purple dragons. All right, so as the universe expands, it cools. And so in the next era, which we call the gut epic, which is between 10 to the minus 43 seconds and 10 to the minus 36 seconds. This is after the threshold of 10 to the minus 43 seconds, when the universe has cooled enough that gravity splits off from the other forces. So we have in our heads an order in which we expect the forces to stop unifying and we expect gravity to be one of the first to stop unifying. Okay, why? Because it's so weird and has always been the troublemaker? This is speculative, right? It could be that we're wrong about this.
53:05 Daniel Whiteson? It's just that in our heads, it makes more sense to combine them in the reverse order, like to combine the strong force with the elector weak, and then unify all the quantum theories with gravity. But we could be wrong. Okay. And it could be that like, you know, we got to do this in another order. So everything here is still very, very speculative, right? Depends on the details of quantum gravity, which we don't have. This next segment depends on the details of the gut theory, which we don't have. So this is one way it could have gone, not necessarily definitive at all. Okay. Right? But in this version, then, you know, the universe cools to a point where we can start to ignore gravity. And we can only worry about the quantum forces when we're making predictions. Right? And gravity is the weakest of all these things.
53:48 Daniel Whiteson? And as the universe gets less and less dense, gravity gets less and less relevant. And so it breaks off faster. Okay, that makes sense. And at this point here, we have gravity, which we know, plus all the quantum forces unified into one force, which we don't have a theory for, we just have like a placeholder for it. But we can talk about particles now because we have the universe mostly dominated by quantum fields. But we don't know what those fields are, right? They're the fields that are part of some theory. We don't have the gut field, right? And we talk about particles in those fields. We call them the X boson, the Y boson. There might be some unified gut force, and these are the mediators of it. I'm sounding like I'm waving my hands a lot because we don't really know.
54:31 Daniel Whiteson? Because again, we don't know how to unify the strong force. So this is just like a placeholder for what might have happened. But like, the creation of the universe is so beautiful and you all came up with the gut force. Like, I just, I, you know.
54:45 Speaker 01 Every time you all have a chance to impress me, but it's your gut. So then just stick with grand unified force and never allow yourself to use the acronym. But all right, anyway.
54:55 Daniel Whiteson? I'll call it the grand ut force. How about that?
54:57 Speaker 01 No, forget it. It's too late. It's too late. You already did it. Move on.
55:02 Daniel Whiteson? Yeah, I know. All right. So at this stage, we think we have a gut force, a single unified force carried by X and Y bosons, but we don't really know, right? It's speculative. Universe continues to expand, continues to cool 10 to the minus 36 seconds. Now the strong force breaks off from the electro weak and now we have two forces, right? And this is the era that we can describe very accurately with our physics because we know about the electro weak force and we know about the strong force. And the universe has cooled and as it cools, these two forces start to behave differently. So again, the fundamental true underlying reality is not changing the laws of physics somehow, but how we describe it effectively changes.
55:45 Daniel Whiteson? Like it makes sense now to talk about the strong force is different from the electro weak force because the universe is cooler, is we're in a different phase where the strong force acts very different. And so it makes sense to treat those calculations separately, right? Instead of unifying them. The elephant's tail has run off by itself.
56:03 Speaker 01 Okay. But so now we would still have elementary particles and antiparticles. And do we know what kind of fields we're dealing with here? Is stuff pretty normal?
56:13 Daniel Whiteson? Yeah. So now the content of the universe are particles we're familiar with. They are the electro weak particles, the W, the Z, the photon. There are matter particles, quarks, electrons, all these kinds of familiar particles.
56:27 Speaker 01 Okay.
56:27 Daniel Whiteson? Right? So the universe is cooled and broken into these familiar fields. And we have ripples in those fields. It's the content of the universe. Then something crazy happens. The universe starts to inflate, meaning very, very rapid expansion. So we were expanding before. Now we have kicked it into high gear. And this part also very speculative, but we think the universe expanded by a factor of like 10 to the 30.
56:52 Speaker 01 Wow.
56:52 Daniel Whiteson? In a very, very short window of time. That's the equivalent. Of taking like a cantaloupe and expanding it to the size of the observable universe.
57:00 Speaker 01 Wow.
57:01 Daniel Whiteson? Like really big deal.
57:03 Speaker 01 Yum.
57:03 Daniel Whiteson? And remember, we don't know the size of the universe. So the universe could be infinite, which means it went from infinite to more infinite, right? Or it could have been finite, so that it went from small or large and finite to bigger, right? We just don't know if the universe is infinite or finite. And exactly when this happened depends on the details of your grand unified theory, et cetera, et cetera. But the crucial thing is that the universe became very dilute. Like you had those particles already and then the universe spread out massively. So now there's just not a lot of particles out there. And so the universe is suddenly very, very cold, right? Very, very dilute.
57:44 Daniel Whiteson? Then inflation ends. So all this energy that's powering the expansion of the universe, the inflation, that gets dumped into the other quantum fields. That energy gets dumped into quark fields and photon fields and all sorts of stuff. And so now the universe becomes very, very dense and hot again. This is called reheating. And this is really the beginning of what we call the hot big bang. Before that, very, very uncertain. After that, things are described very, very well. Everything we just said up to now is speculative and could be totally wrong. Everything we're going to say from now on is very, very well established. And what we mean when we say the big bang from this moment,
58:25 Daniel Whiteson? somehow maybe via inflation dumping all the energy and reheating all the fields, the universe is very dense and very filled with familiar particles.
58:34 Speaker 01 And are we still dealing with the first second of existence?
58:39 Daniel Whiteson? We are up to 10 to the minus 12 seconds.
58:42 Speaker 01 So still the first second.
58:45 Daniel Whiteson? We're still dealing with the first trillionth of a second.
58:47 Speaker 01 Yeah. So that's pretty amazing that.
58:50 Daniel Whiteson? Yeah. A lot of stuff has happened so far and just a few ticks on the clock. Absolutely. And then something really exciting happens, which is, look, you've created all these particles. You have matter particles, you have antimatter particles. Most of those annihilate. So the universe filled with matter and then those particles find each other, annihilate. And now the universe mostly filled with radiation with a little bit of matter left over. Because you had a little bit more matter than you had antimatter. And that little bit of extra is what turned into me and you and most of the stuff in the universe. This tiny little extra bit of matter. We don't know why there was that asymmetry. We can't understand it. We have some explanations for it, but not nearly enough to explain what we see.
59:35 Speaker 01 Wait, so that that tiny little bit of matter is all of the matter that still exists today? That seems like a lot of matter.
59:41 Daniel Whiteson? It's a lot of matter, but it's a tiny fraction of the original amount of matter.
59:45 Speaker 01 All right, I guess it's all about perspective, but.
59:47 Daniel Whiteson? Yeah, so the universe was dominated by radiation. Like, most of the energy in the universe at that time was in photons from annihilation.
59:55 Speaker 01 Okay.
59:57 Daniel Whiteson? And so then things keep cooling. And when we get to 10 to the minus 12 seconds, this is another phase transition of the universe, where we're now cool enough that it matters that the weak force has heavy massive bosons. And so now we say the weak force breaks off from electromagnetism. By which we mean, you know, none of the fundamental rules have changed. The only thing that's changed is the temperature of the universe. But now it doesn't make sense to treat these two things together because it matters that one of them has really massive bosons and the other one has a massless boson. They start to act very differently, right? We're now hiking over those mountains instead of flying over them. And it matters if you're carrying a really heavy pack or not. And so we break those up and we treat them differently.
1:00:42 Daniel Whiteson? Does that make sense?
1:00:43 Speaker 01 How did this all happen in a second? I'm, my, my brain is kind of trapped on something else. How did this all happen in a second? And how did we figure out the timing down to the like point oh, oh, oh, oh, oh? But like, wow.
1:00:57 Daniel Whiteson? I know. It takes me like an hour to get up and have coffee, even think about getting anything done. And by that time, the universe is already done all this stuff.
1:01:04 Speaker 01 Right.
1:01:05 Daniel Whiteson? Yeah, it's crazy. And it's a fair question. How do we know this stuff? We know this by extrapolating our model backwards in time. And these models we've built from lots and lots of observations, the cosmic microwave background radiation, large scale structure, baryon acoustic oscillation. We've talked about all those things on the podcast, dig into those. We have really, really well constrained models for a lot of this stuff. Those models don't work perfectly. There's still like mysteries right now about that expansion. It's called the Hubble tension. So there's definitely things to learn, but it's a pretty well established timeline after the reheating.
1:01:39 Speaker 01 That's incredible. That was one hot second.
1:01:41 Daniel Whiteson? Yeah. And it's still going. Between 10 to the minus 12 seconds and 10 to the minus six, you still have enough stuff in the universe to have a quark gluon plasma. Things are still pretty dense. So quarks and gluons are floating around and it's still hot enough that they're not bound into objects, right? They can just smoosh around like at the heart of a neutron star. And then around 10 to the minus six seconds, things cool down and you form protons and neutrons. And then for like, literally two minutes, there's enough heat and temperature in the universe for fusion to happen. Like the kind of fusion at the heart of stars like makes heavy stuff that happened in the universe for a hot minute. And it made a little bit
1:02:24 Daniel Whiteson? of helium and a little bit of lithium. And that's called big bang nucleosynthesis. And that's very, very sensitive to lots of the details. How hot was it? How many quarks were there? We know a lot about the early universe, just from measuring how much helium and lithium was made in that first minute. Super duper powerful test of the early universe. And then 400,000 years later, of course, things cool down and electrons find their protons and we get neutral atoms and the universe becomes transparent and we see the cosmic microwave background radiation. So that's the sort of timeline of the universe from the beginning when it was really hot, cooling down, and we enter different phases of effective descriptions of the universe.
1:03:06 Speaker 01 Wow, it feels like the universe like burned out. Like it had its first second was really, really active. And then it was like, You know what? I did too much. I did too much. And then it just really slows down. And yeah.
1:03:19 Daniel Whiteson? I don't think it has any regrets, you know, I think what happened in the universe is beautiful.
1:03:23 Speaker 01 It is, it is.
1:03:25 Daniel Whiteson? So back to Delair's question, he asked, what was the form of energy? Was it in photons? And so, you know, when the grand unified theory was ruling as the effective theory of the universe, we don't know because we don't know what that theory looked like. We call it the X and the Y particles, just as sort of placeholders, because some candidates have those two bosons in them, but we don't know. He asks, what caused the force to break down? It's just that the universe cools. And so then the rules you would use to describe things in a useful way change. Not that the rules of the underlying universe have changed, just our effective theories, our descriptions of the universe change. He asked, what were the steps of the breakdown?
1:04:05 Daniel Whiteson? So we think that gravity broke off first, and then the strong force, and then the weak force, and now electromagnetism. And he asks also, is there any relationship between the breakdown of this force and the inflation? Did one cause the other? So we don't know for sure, because a lot of this is before the time that we can study really, really well. Inflation is still speculative, and how grand unified theories treat inflation depends on the particular grand unified theory. So there's a complicated interplay there that we just don't know about really concretely.
1:04:35 Speaker 01 So what I got from your conversation with Ethan was that there's maybe a lot of disagreement about a lot of stuff. And so if I talked to, you know, 10 different people who had the same job as you, and they were given the same set of, I know, none of them as good as you, of course, of course. And they were given-
1:04:55 Daniel Whiteson? You're gonna talk to other particle physicists?
1:04:57 Speaker 01 Never, no, never, never. I promise. You're being very controlling, Daniel.
1:05:03 Daniel Whiteson? I suddenly have these feelings of jealousy. Oh, my gosh.
1:05:05 Speaker 01 Oh, get over it. All right. If those sets of questions got sent to 10 other particle physicists, would they give a roughly similar description or talk as you gave? Or would they have a very different sense of like what we know and where the uncertainties are?
1:05:23 Daniel Whiteson? I think that we would all agree on the later stages because those are things we've measured, we are pretty confident about the very early universe stuff, inflation. And before that, very speculative, you might get different opinions about what's most likely to work out eventually as a model. And I think probably I have an unusual philosophical take for a particle physicist. I was thinking about emergence and effective theories differently than many particle physicists, but I'm not sure.
1:05:53 Speaker 01 Okay.
1:05:54 Daniel Whiteson? Maybe I'll ask them over lunch and try not to disturb their guts with too many "yeez."
1:06:01 Speaker 01 Well, I hope that goes well. Let me know. This was a ton of fun and we learned a bunch. Let's hear what our listener has to say. Thank you, Daniel and Kelly, for answering my question. That was really great. I have a better understanding now of the early stages of the universe. And I think what helped in that clarification is that two approaches you used to address the issues or the questions. One is the energy level, what happens when we crank up the energy? And the second approach was the chronologically, how the universe evolved and the forces got, you know, broken down. And also what helped understanding it also, the example of the different phases of the
1:06:46 Speaker 01 water. So looking at the universe and the forces in that way also makes it easier to understand. And also I like very much the clarifying question by Kelly. It seemed like she was channeling my questions. So that was really very, very great help in getting Daniel to explain the answers in a very clear way and very logically. So once again, thank you very much. It was really fun listening to it and I enjoyed it. Thank you. Bye.
1:07:17 Daniel Whiteson? All right. Thank you very much, Delair, for sending in your question and for riding with us on this journey back in time to unifying all the forces and then forward again to breaking them up to explain the universe we know and love today.
1:07:31 Speaker 01 Thanks for joining us, everyone. Until next time.
1:07:40 Daniel Whiteson? Thanks, everybody, for listening. Please go and do us a favor and rate the show on whatever podcast app you're using. It really helps people find us.
1:07:48 Speaker 01 Daniel and Kelly's Extraordinary Universe is edited by the amazing Matt Kesselman.
1:07:53 Daniel Whiteson? He really is a wizard. You can also find us online on Blue Sky, Instagram, and X, D and K Universe. Come engage with us.
1:08:03 Speaker 01 You can email us at [email protected] . We really do want to hear from you.
1:08:08 Daniel Whiteson? And you can find our website, www.danielandkelly.org, where you'll also find an invitation to join our Discord, where everybody comes and talks about the amazing universe.
1:08:19 Speaker 01 And we also have the most amazing moderators. This is an iHeart Podcast. Thanks for joining us.
1:08:29 Speaker 05 Are you looking for support in your weight management journey? Zepbound terzepatide may be able to help. Zepbound is a prescription medicine used with a reduced calorie diet and increased physical activity to help adults with obesity, or some adults with overweight who also have weight-related medical problems, to lose excess body weight and keep the weight off. Zepbound is approved as a 2.5, 5, 7.5, 10, 12.5, or 15-milligram injection. Zepbound contains terzepatide and should not be used with other terzepatide-containing products or any GLP-1 receptor agonist medicines. It is not known if Zepbound is safe and effective for use in children. Don't share needles or pens or reuse needles.
1:09:11 Speaker 05 Don't take if allergic to it, or if you or someone in your family had medullary thyroid cancer, or if you've had multiple endocrine neoplasia syndrome type 2. Tell your doctor if you get a lump or swelling in your neck. Stop Zepbound and call your doctor if you have severe stomach pain or a serious allergic reaction. Severe side effects may include inflamed pancreas or gallbladder problems. Tell your doctor if you experienced vision changes before scheduled procedures with anesthesia, if you're nursing, pregnant, plan to be, or taking birth control pills. Taking Zepbound with a sulfonilurea or insulin may cause low blood sugar. Side effects include nausea, diarrhea, and vomiting, which can cause dehydration and worsen kidney problems. Talk to your doctor.
1:09:51 Speaker 05 Call 1-800-545-5979 or visit zepbound.lily.com.
1:09:59 Speaker 06 If you're a fight fan and you haven't seen the BKFC app yet, you're missing the world's most exciting combat sport. Bare knuckle fighting championship has changed the game. No gloves, no stalling, no boring rolling around on the ground. Just pure violence and pure entertainment. The BKFC app includes live events, past fights, original series, behind the scenes access, merch discounts, and more. Only $7.99 a month or $49.99 a year. Get the BKFC app at BKFC.com.
1:10:29 Speaker 04 With ChatGPT, you can do more than get answers. You can get things done. Whether you're leading a big project, planning an elaborate trip, or trying to balance work and life, ChatGPT can help. Give it a goal, plus things like files, notes, or project plans, develop a trip itinerary with daily updates, or create a prioritized schedule so you can spend less energy sorting out the details and more on bringing your biggest ideas to life. Get started at ChatGPT.com. This is an iHeart Podcast. Guaranteed Human.
Previous Listener Questions #42 Next The science of bathing (featuring Dr. Katrine Whiteson) Page updated October 30, 2026 · transcript and summary are machine-generated