Daniel and Kelly’s Extraordinary Universe - Why is the universe inflating?

Episode Date: January 14, 2020

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I know how overwhelming it can feel if flying makes you anxious. In session 418 of the Therapy for Black Girls podcast, Dr. Angela Neal-Barnett and I discuss flight anxiety. What is not a norm is to a lot. allow it to prevent you from doing the things that you want to do, the things that you were meant to do. Listen to therapy for black girls on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Hey, Daniel, did you have a good holiday break?

Oh, I did, but, you know, as usual, I ate too much. You mean you ate cosmically too much? Yeah, I totally overdid it. I'm like on the verge of becoming a black hole myself. Would you say your waistline is inflating? I'd say a few more bites, and I'd be risking becoming my own personal Big Bang. Big Daniel. I'm talking dark matter here, people. Oh, no. Let's cut to the theme song. Cut to the theme song.

Hi, I'm Jorge, I'm a cartoonist, and the creator of PhD comics. Hi, I'm Daniel. I'm a particle physicist, and I am actually full of dark matter. Welcome to our podcast, Daniel and Jorge, Explain the Universe, a production of IHeart Radio. In which we examine all things fascinating and amazing and bonkers about our universe. and explain them to you in a way that you can actually understand. So it's a new decade here. And so, Daniel, what do we have to look forward to in physics? What do we have to look forward to in physics?

Wow, so much. There are all sorts of new exciting telescopes coming online that will let us see further and further into the ancient past. The Large Hadron Collider is going to keep running and maybe discover some crazy new particles. But, you know, the best thing about looking forward in physics is that we have no idea what we're going to discover. there are always surprises out there waiting for us.

There are surprises everywhere, yeah. That's awesome. Yeah, there might be, hey, a new kind of plantain or a strawberry-flavored banana discovered by scientists somewhere. You never know. Science. It's what's for dinner. And so there's a lot of good stuff to look forward to.

I look forward to in 2030 looking back and thinking, man, those folks in 2020 had no idea what was coming. Oh, interesting. You look forward to the future so you can laugh at the point. past. Yeah, it's a wonderful feeling to think, look at what we know about the universe, and look at how the people before us, including ourselves 10 years ago, really had no clue what was coming. That's exciting to me because it makes me enthusiastic about the next 10 years, you know, the mind-blowing discoveries that physics and the rest of science will reveal.

Man, you're making me feel bad about humans 2010. They were so clueless. Oh, man. with their like new Facebook craze and they didn't even have TikTok or Instagram. No, but we learned a lot about the universe in the 2010s. You know, we saw a whole bunch of new exoplanets and discovered the Higgs boson. And, you know, there are really some pretty big shifts in our understanding of the universe in the last 10 years. And since science is just accelerating exponentially, then I look forward to even more mind-blowing stuff in the decade to come. Yeah, and technically we have more.

universe now than we had in 2010, right? The universe is constantly expanding and getting bigger. There's new space being created. So we have also that to look forward to, right? In the future, there will be even more space. That's right. In the future, you will occupy a smaller fraction of the universe because the universe is inflated. Oh, no. Wait, so you're saying that the people in 2010 were more significant than we are? Well, you know, what's the fraction of infinity is still zero? So, relatively speaking. But, you know, I had a listener write in and make a really fascinating point about the expansion of the universe that I had never thought of before.

Oh, really? Yeah. And they said, well, what about in time travel books? If you go back in time, then doesn't your body occupy a smaller space in the universe back then than it does now? And how do you account for that? And it's true. You know, the space that you occupied 20 years ago has expanded to a larger space.

And so somehow you have to factor that into your time travel novel. Whoa. Like if you send your consciousness back, it has to somehow fit into a smarter package or something. Yeah. It has to shrink exactly. You got to squeeze your way back into the universe from 10 years ago or 20 years ago. On today's episode, we are going to not look forward in time, but we're going to try to look backwards in time, almost as much as you can look backwards, right? That's right.

We're going to try to rewind all the way back to the very beginning. beginning. Because I've noticed that in conversations with listeners and just with folks around campus, that there's still a lot of misunderstandings about the very beginning of the universe. Right, because right now we have a lot of space. There's a lot of universe, but at some point in the past, there was very little of the universe. I don't know. I mean, I think right now, the universe is pretty dilute, but in the past, the universe was more dense. It could be that the universe has been infinite since its conception. So in that sense, it doesn't really make sense to talk about having less universe. It's just more compact. Right. A denser infinity.

Yes, a denser infinity. Versus a watered down infinity, which, you know, just doesn't taste as good. That's right. But I think a lot of people, when you talk about the beginning of the universe and the Big Bang, they have sort of an old idea in their head of what the Big Bang was. Like, there's just this big explosion from a singularity. And that's not really the modern view. Wait, you're saying the name Big Bang, doesn't actually describe the Big Bang? I think it was pretty big, and it might have been a bang. So, you know, from that point of view,

but I think the ideas in people's heads need updating. I see. It's a kind of Big Bang. Yes, exactly. Big Bang encompasses like a whole spectrum of ideas, and physics has moved on while popular conception is sort of stuck in the 80s version. Right.

And so this is a question that you said to me, a lot of listeners as wrote in to ask about, A lot of people are wondering and asking us to explain what this idea is. Yeah. And so as usual, we want to cater to our listeners. We want to answer the questions that are in your minds. And we want to bring you to the forefront of science. We want you to understand what scientists out there who are experts in this field,

who know the most that any human has ever known about the beginning of the universe, what they are thinking about. We want to explain it to you in a way that makes sense. So that's our goal. So today on the episode, we'll be asking the question. What is cosmic inflation? Inflation. Inflation. That's right. It's not controlled by the Federal Reserve.

It's not the reason why your bank account is emptying. Wait, wait. You mean cosmic interest rate? Don't make a difference here? No, we can't borrow money from the other universe or anything. Can my cosmic debt somehow bring it down? That's your carmic debt, actually. And there's nothing you can do about that. other than do good things for people, like explain the universe to them. I think that's definitely a positive on the karmic debt.

Right, right. But today we're talking about cosmic inflation. And that kind of sounds simple. It just means that the cosmos is getting bigger or got bigger. But in this case, scientists use this phrase for something very specific, right? Like a very specific moment in time

right after the Big Bang. Sort of. It's both a specific moment in time that's after the Big Bang, it's also sort of our modern view of what the Big Bang was. And it also connects the like primordial inflation, these first moments when the universe was expanding with the current inflation and says maybe these things are connected. So it's sort of like saying the Big Bang wasn't the moment of creation. It happened just afterwards.

And it's saying maybe the Big Bang is still banging. We're still banging. Yes, exactly. That's how big this bang is. Well, it sounds like it's pretty interesting and maybe there are a lot of subtle ideas here. So we'll get into all of that. But first, as usual, we were wondering how many people out there had heard of the phrase cosmic inflation and if they knew what it was. That's right.

And so since it was winter break and UC Irvine was closed, I walked around coffee shops in Irvine. And I asked random strangers who were amenable to being interrogated about physics topics, while on their holiday break, if they knew anything about cosmic inflation. Here's what they had to say. Oh, I feel like I've heard the term, but I do not know what it means. No clue.

Best guess? Cosmic inflation. Is that like the theory where everything in space is constantly moving away from itself? Like there's an explosion and everything's still expanding? Yeah, cool. I have no idea. I think it means the Earth is like crowding together,

maybe, like everything's coming together. But I don't know. The universe is expanding and getting bigger with each, as time passes. So something that's happening now or in the past? It's still happening. The expansion of the universe. And is that something that's happening now or the beginning of the universe? It's always been happening.

Yes. What is it? That's essentially the basis of the Big Bang Theory. Okay. When did it happen? 14.3 billion years ago? We might have more satellites in space. I guess, or space stations or something.

Okay. I have no idea. I mean, it sounds like the expansion of space. Cosmic inflation, no. All right. A lot of noes, I feel. Not a lot of inflated answers here. Yeah, a lot of nose.

No, no. And some confusion. People thinking like space is getting smaller or the Earth is getting more crowded. Maybe they thought space was getting devalued as a currency. Yeah, maybe there's the negative, the flip side to it. That really surprised me. The market for space is oversaturated.

Better spend your space now before it's worth nothing. Better use it up. Better eat more so you can take up more space. That's my New Year's resolution right there. I see. Eat more dark matter. Take up more space. Make more dark matter.

But there were some core ideas here. You know, people had heard of some connection to the Big Bang or some ideas for things that happened in the early universe. So there's definitely some nudge. it's there. Yeah, a lot of people said it's related to the expansion of the universe, which is, I guess, not a big stretch, right? Inflation and expansion sort of sound the same. Yeah, and in fact, I think they're right. It is related to the expansion of the universe as far as we know, which is not very much, it turns out. And this is fascinating to me because it's

something where we've made a lot of progress in the last 20 years coming up with new crazy ideas about the universe, but something that we're also still puzzled over. Like, there are huge, unanswered questions about the Big Bang and cosmic inflation, there are things that scientists are arguing about. You know, the guy who came up with inflation, one of the architects of the theory, Paul Steinhardt, is now the guy arguing against the theory most vociferously, yeah. He's trying to deflate inflation. That's right.

He's trying to pop the bubble of his own creation. So what's interesting, I think, is that, you know, if you had asked, what is the Big Bang, a lot of people might have said, yes, and it's had some ideas about that it's about the beginning of the universe, but cosmic inflation, which is almost as important, doesn't have the same kind of market recognition. Yeah, and that's what we're going to try to correct today on the podcast. We're going to bring some panache to cosmic inflation. We're going to show people how Big Bang is sort of the old busted theory, and cosmic

inflation is the new hotness. It's the new bang. It's the new bang. That's right. Out with the old bang, in with the new bang. It's the 2020s. Come on. Are you still banging the old way?

man, what's wrong with you? Try our new, physics-based banging. Yeah, I don't know what advertisers are going to go for that line, but somebody out there has got a product that fits that. All right, Daniel, so let's get into it. Let's get into this idea of cosmic inflation. So first of all, how would you define inflation in a physics way? Basically, inflation is the expansion of space.

It's saying, let's take space. and stretch it. Let's make space bigger. And it's important there to understand that it's not the moving of stuff through space. It's really the stretching of space itself. So are we stretching space or creating new space? Both.

Both, yes. That is how you stretch space. You create new space. I see. Like there's more meters. It's not like the meter got bigger. There's just more meters of space. Yeah, there are more meters of space.

So stuff can be further apart without moving through space. Right? It's like if you take a ruler and you put a penny on the one meter and on the two meter and then you stretch the ruler. The ruler itself is like made out of elastic and you stretch the ruler to make it longer, then the two pennies are further apart, even though they haven't moved relative to the ruler. That's expansion of space. That's inflation of space. Right. But it's not just that the ruler expanded. It's like the wood of the ruler got bigger. Yeah, you definitely add more to the ruler. Okay, and so that's different than kind of the old idea of how the Big Bang happened after the beginning of time. Yeah, so let's dig into that in that way. Let's define what I think most people think the Big Bang was and the sort of old idea of what the universe was. And then let's contrast it with sort of what they should replace in their heads with.

Okay, so what's the old bang? The old bang, I think, is this idea that the universe started from a point, like a singularity, an infinitely dense, dot, a primordial atom, which was a point in space. It was like somewhere, and it was infinitely dense. And remember, like, nobody has any idea where this thing might have come from. What could have created it? But that sort of just, like, swept under the rug, you know, the primordial rug. Like, well, you know, we don't know what came before, but let's just start from there.

Right. It was like a little tiny, infinitely energetic package in sitting in space, actually, right? Like, it was, people think it was like a grenade sitting there. Right. It was really, really small. Exactly. And that's a really key insight there. That space was already created. You already had space and you just had this dot in space and then it exploded. And that stuff then flew out. And it spread out and slowly got more and more dilute, right? Less dense like an explosion would. And spread out to eventually form of the universe. And that's the stuff moving through space. And that's what we call in science the hot big bang model. The hot big bang is now the old big bang. that's right you know it's like your ex-girlfriend or boyfriend you still think they're hot but it's not really for you anymore

oh man so that's probably the idea most people have in their heads when you say big bang or creation in the universe and and i think that's what i thought that the big bang was you know way before when i was in high school or before i started hanging out with physicists was that the big bang is really just like a bang like everything that we know about was in a small spot and then it just exploded and now all the stars and galley Lexes and dust that was in that little but dod are now flying through space outwards. Yeah. And, you know, when you started hanging out with physicists is basically the moment your universe was created.

Everything else before that is like a waste of time. I see. You created my universe, Daniel. My universe started. There's nothing before I met you, Daniel. You're supposed to go with you complete my universe. You're saying you made my universe, Daniel. That's even more romantic.

Wow. well all right yeah I think I want to back pedal on that a little bit but no you're right and I think that's what most people think as sort of how the universe began and you know there's lots of questions there but one big problem with that conception is that it has a center has a place where the Big Bang happened and if you were looking at the explosion from any point of view you would see stuff sort of flying sideways unless you happen to be at the center

then everything would be flying in a certain direction right and you could tell maybe where the center of the universe was, just by looking at where all the things around you are flying away from. Precisely. And as a foreshadowing moment, that's not what we see when we look out into space.

Yeah, so at some point, a humanity, physicists and scientists, decided or started to realize that this old model of the Big Ben was not the right one. Yeah. I mean, it's a good first draft. Like, we're thinking about the universe

is expanding and what could have created it. You know, we don't want to criticize those scientists as being dumb or something. It's just sort of like science evolves and this is how it evolves. You have an idea. You compare it to what you see. It doesn't quite work. So you improve the idea. Right.

They did a bang-up job. It was a big project. But I guess what I mean is at what point did we start to sort of realize that maybe this view was not the correct one? Well, there's been a lot of problems with the Big Bang basically since early on, you know, when Edwin Hubble looked out into the universe and realized, it's like a hundred years ago, that the universe was expanding. That's sort of what gave birth to this concept of the Big Bang. He's the one who discovered that everything was moving away from us, and everything was moving away from us, sort of the same speed in every direction you looked. So this is an outstanding problem for the Big Bang for a long time,

and it wasn't until this idea of inflation came along that it helped solve it. So the Big Bang was not like totally accepted for many, many decades. And one problem with it was, you know, are we at the center? Why does it look like we are at the center? Oh, I see. He tried to figure out where the center of the grenade was. And so he looked around and he found that the center was us, which is weird. Yeah, it's weird.

Which was like too coincidental. It's too coincidental. Anytime in science you appear to be at the center of the universe, you got to wonder, hmm, am I biased or just thinking about this wrong? know you want to avoid coincidences. You want to avoid things that are really unlikely or especially things that put humanity in the very important place in the cosmos because we've made that mistake before. Right. Like before we thought we like the earth was the center of the solar system. More than that. We thought it was the center of the cosmos, right? We thought everything was created

around the earth. Yeah. Right. Right. And then it turns out that the sun, not even the sun is the center of the universe. It's like just one star in the rotating galaxy, which is part of something even bigger. Yeah. And we like to think more democratically now. We like to think that every point in space is equal, not because they're voting or anything, but just that, you know, there should be no special locations because special locations require special explanations. It just makes the most sense if everywhere in space follows the same rules and is the same. And that's why like the Big Bang as a point never really made sense to me, because then you can always ask like, well, why there? Why did the big bang start there and not like a meter over or over there or a light

ear in the other direction? Why there and nowhere else? And so you avoid those questions if you say everywhere in the universe is the same. All right. So that's the old bang, the old hot bang. And now let's talk about the new hotter bang, I guess, in terms of trendiness. And why we think it happened and why is it still a mystery? But first, let's take a quick break. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal.

Apparently, the explosion actually impelled metal, glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and Order Criminal Justice System is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app.

Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes,

My boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age.

And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Scott Barry Kaufman, host of the secretary. psychology podcast. Here's a clip from an upcoming conversation about exploring human potential.

I was going to schools to try to teach kids these skills and I get eye rolling from teachers or I get students who would be like, it's easier to punch someone in the face. When you think about emotion regulation, like you're not going to choose an adaptive strategy which is more effortful to use unless you think there's a good outcome as a result of it if it's going to be beneficial to you. Because it's easy to say like go you go blank yourself, right? It's easy. It's easy. It's easy to just drink the extra beer. It's easy to ignore, to suppress, seeing a colleague who's bothering you and just, like, walk the other way. Avoidance is easier. Ignoring is easier. Denial's easier. Drinking is easier. Yelling, screaming is easy. Complex problem solving, meditating,

you know, takes effort. Listen to the psychology podcast on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts. Okay, so, Daniel, you're telling me that the universe, the Big Bang is not like a granite that exploded, that was full stuff and then exploded, but the universe, the Big Bang is actually something different, where new space is being created and space is being stretched. It's not an explosion. That's right. And we still have to reconcile the fact that we think the universe was more dense in the past than it is today. And that makes you want to. go to the explosion explanation because you know like how else can it happen right because a grenade was denser before the explosion right so you might be tempted to apply that to our universe yeah so another approach and a better way to think about it though it requires swallowing a really big idea is that the big bang essentially happened everywhere all at once that the universe wasn't

created as a tiny singularity which then exploded but that the entire universe, an infinite universe, filled with an infinite amount of stuff, was created somehow, we don't know how, in a very dense state. And the Big Bang was the expansion of that state, the stretching of space itself to make that stuff more dilute, but that it was created everywhere and happened everywhere all at once. So like, that's an infinitely big bang. Okay, so you're saying that the universe has always been infinite. It's not like it started as a point and became exploited into infinity, you're saying that the universe was always infinite, but that before it was like a dance and compact infinite,

infinity, but now it's more of a bigger and more expanded infinity. Precisely, that's the idea. And of course, we don't know the size of the universe, and we don't even know its shape, but this is the idea. It explains what we see, an infinite universe, created infinitely big and always filled with an infinite amount of stuff. There's no edge to the matter, and there's no edge to the universe.

and it just started out really hot and dense and then stretched out. Right, but that's only one possibility, right, that it's infinite. It could also be that the universe is finite as far as we know, right? It could be, right, but it at least has to be big enough to fill our observable universe with a homogenous stuff, right? If there is an edge to the stuff in the universe, we don't see that. And so it has to be really, really big and pretty uniform, at least in our neighborhood. Oh, I see. It's possible that there's an edge to the stuff in the universe.

But it's sort of simpler. Somehow it's weird. It's weird. It's simpler to imagine an infinite universe with infinite stuff because then you don't have to explain the edges, even though I can't explain how you create an infinite universe with an infinite amount of stuff in it either. Well, nobody can explain a finite universe either. Yeah, right. All this stuff defines explanation. But, you know, it's like pushing the rock further up the hill.

You don't have to have the answer to every question. you just have to have the answer to this question and then it gives you the next question. Like, if you say, let's assume the universe started infinitely large, filled with an infinite amount of stuff, then what would have happened and you can show that that's consistent with what we see so far, then you get to go back to that other question,

say, okay, let's roll up our sleeves and figure out how it's possible to create an infinite universe. Is that your approach to teaching as well, Daniel? Just make it up as you go along. Push all the problems off until tomorrow. So that's my approach to life, yes, to my inbox as well. Oh, good. Yeah, and so the idea is you create an infinite universe,

filled with an infinite amount of stuff, but it's very hot and dense, right? It's like a huge singularity, essentially. Okay, so I think you're saying that the best way to think about the Big Bang is not as like a little point that exploded, but just as an infinity going from a really dense infinity to a bigger infinity. Yeah, and that's what cosmic inflation is, is taking that really dense infinity and stretching it out to a much more dilute infinity.

Because that is what we see. That's what we have evidence for, right? Like we see that the universe is really sparse and kind of empty now, and we see that everything used to be much, much denser. Yeah, we need to have inflation in order to explain a bunch of stuff that we see in the universe. And we can get into that in a few minutes, if you like. But this explains why the universe looks the way that it does. And without inflation, the universe doesn't really make sense. Like, if you just created the universe at this current density and set it expanding now 10 billion years ago,

it wouldn't make sense. It doesn't explain what we see. So you need to have this inflationary period in order to get all the sort of the clumpiness and the structure that we see and the temperature of stuff all correct. Okay, so I think that's another key concept about inflation, which is that it's not, you know, the universe went from a dense infinity to a wider infinity, but it didn't do it sort of evenly, right? Like there was a period of time where it was really expanding really fast, and now it's expanding but not as fast. And so what do you call inflation? Is it that rapid expansion, or is it the whole thing, or is it that still kind of undecided?

That's a little bit fuzzy. Yeah, I think if you talk to most cosmologists, they would think about inflation as this very narrow period from 10 to the minus 36 seconds after somehow the universe was created to 10 to the minus 32 seconds after the universe was created in which you had this enormous expansion in the universe. It seems like a factor of 10 to the 26. That's what they would think of as inflation. But they also like to think about, well, you know what expansion is still happening. And so maybe this is still really part of inflation. But that was the most dramatic moment. And so I think, you know, if you talk about inflation,

that's the moment that people are thinking about. Oh, I see. Like we're maybe just at the after party of the inflation. You could technically maybe still call it inflation night, you know, like the Oscars night. That's right. Is the celebration after the Super Bowl part of the Super Bowl? Yeah, you know, but it's nothing like that touchdown moment.

Yeah, like the tailgating count as part of the event, surely. Yeah, exactly. The tailgating created the whole thing. It's only because of the fans that you can even have a Super Bowl. There you go. And one of my favorite things about inflation is just sort of the mind-boggling numbers.

We're talking about a really brief amount of time. 10 to the minus 32 seconds is like impossible to think about. We talked recently on a podcast about how long particles live. And I said that they last like 10 to the minus 23 seconds, which seems impossibly short. But, you know, compared to 10 to the minus 36, That's a huge amount of time. The idea is that the universe went from almost or actually infinitely dense,

an infinitely dense infinity to a less infinitely dense infinity in a matter of seconds. Or, you know, fractions of a second. And the expansion also is incredible. I mean, 10 to the 26 expansion is hard to get your mind around. Yeah. It would take one meter and expand it to 10. billion light years. That's what happened at the beginning of time.

Yeah. Is that a meter, like suddenly a meter became 10 billion light years. Yeah. So the stuff that's in a meter of space got stretched out and spread out over 10 billion light years. In a matter of 10 to minus 32 seconds. Yeah, one Pachinko second or whatever that unit is. Pachinko second. You know, if you're a cosmologist, you get to make up whatever terms of light because

you're, this is uncharted territory in terms of scientific prefixes. Right. I think I think you should claim it right now. Go online. Tochink, that's the sound of me claiming Pachink a second. And then gaining royalties from it. Then you get to ching seconds. And the other thing to wrap your mind around is that this is stuff that's happening faster than the speed of light. You know, light can't travel 10 billion light years in 10 to the minus 32 seconds, obviously, right? It would take 10 billion light years to cross that distance. That's right. Even Hans Solo would take 12 par six to get to.

that far. Which Han Solo, though? The D-1 or the old? Of course, the old one, the original. And I want to give a shout out to all those fans out there who wrote in and gave me an explanation for why Han Solo quoted his Kessel Run Time in Parsecs because he found a shortcut. He wasn't using it as a measure of time.

He was referring to the fact that he took a trip near some gravitational well, which basically shortened his trip through space. So thank you to all those fans who educated me on the physics of Star Wars. Sounds like a whole episode we should do. We should, certainly. But the idea here is that space expanded faster than the speed of light. And so for those of you physics aficionados who are thinking, what, nothing can go fast in the speed of light.

You're right that nothing can go faster than the speed of light through space. But there's no limit to how fast space can expand. Really? No limit, do you think? You think space can expand infinitely? Well, it made a pretty impressive expansion in the first few moments of the universe. I mean, I'm impressed, we are not aware of a limit. I mean, there could be a limit, but, you know, we have evidence that this expansion happened

at a mind-boggling speed. So things that used to be close by, they used to be like a meter apart, where all of a sudden cosmically separated, they were in their own essentially observable universes. You know, they could no longer see each other or communicate with each other. Wow. That's a little sad, you know, something tore them apart. Yeah, something tore them apart. And that's actually an important clue as to why we think inflation happened.

And, you know, this kind of expansion is the same kind of expansion that we're talking about now, that we're talking about for dark energy. You know, people in the interviews who said, huh, isn't space expanding now? Is cosmic inflation talking about the current expansion of the universe? Maybe, right? There's no difference in the kind of expansion we're seeing now that's driven by dark energy and the kind of expansion that we're talking about for cosmic inflation. They're the same expansion of space.

Right. And so this was what we, that short, super crazy period happened near the beginning of time. And it happened really fast. But we don't know kind of why it happened, right? We don't know what happened. And we don't know why it stopped happening and sort of cooled off for a while. And then we don't know why it started happening a little bit again five billion years ago when dark energy sort of have started taking over the universe.

So, yeah, we don't understand the mechanism of it at all. Right, but it is pretty crazy. And maybe is that kind of where the idea of a Big Bang came from? Like from this crazy expansion. It's almost like an explosion of space, right? You might call it, or a bang of space? I think the original name Big Bang came as a sort of a joke trying to mock somebody else's scientific theory.

And that was thinking of the universe is starting from a point and an explosion through space. And people were like, What, are you suggesting as a theory of the whole universe, something as whimsical as a big bang? You know, I think probably said with a snotty British accent. A sneer. Yeah, exactly with a sneer, right?

The curled lip. But it caught on. It caught on. Like the Big Mac. Like the Big Mac. It was catchy. Precisely. And, you know, it has its own special sauce.

But it is sort of incredible that, I mean, it's sort of, like, if you were alive back then, it would. you would not survive that, right? It would feel like an explosion. It would feel like this crazy, violent, you know, sudden thing that just happened suddenly. Yeah, if you're two meters high, then you would suddenly become a 20 billion light year-long stain on the universe, right? I mean, it would not be comfortable. I feel like I'm a stain on the universe now, Daniel.

Yeah, but you're localized. You're only like two meters of a stain. I'm not infinitely stained. Do you want to be a cosmic smear in the universe? You know? And if you are building that. that time travel device, be careful. Don't go back too far because you do not want to experience cosmic inflation. Right. But, you know, space and time are tied together. So is this, was time also

moving slower or was time moving, is this all measured at the same time scale? Oh, yeah, that's a great question and a deep one. And we don't really understand, but we're measuring these things according to our time. So our proper time. You know, what would you have experienced in terms of time, if you're living through that period, I don't know. And we don't really have a mechanism for explaining how this happened. We just sort of describing that it did. And so we don't understand, like, is this part of general relativity? There's some term you can add to the equations of general relativity that create this expansion, or is it something totally different that is stretching space. And so the answer to how it affects time depends a little bit on the details of what's

doing it, whether it's part of general relativity or not. Wow. I think time, it's, itself cost inflation. How about that? Is that a new idea? Can I lame credit to that sci-fi novel? That's right. That is officially your idea, Jorge. I look forward to seeing the paper you're writing on it. All right. Let's get into why we think cosmic inflation even happened in the first place. And let's get into what is still a big mystery about it. But first, let's take another break. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys.

Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal, glass. The injured were being loaded into ambulances. a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism.

Law and Order Criminal Justice System is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. My boyfriend's professor is way too friendly, and now I'm seriously suspicious.

Well, wait a minute, Sam, maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor and they're the same age. It's even more likely that they're cheating.

He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast. Here's a clip from an upcoming conversation about exploring human potential. I was going to schools to try to teach kids these skills and I get eye rolling from teachers

or I get students who would be like, it's easier to punch someone in the face. When you think about emotion regulation, like you're not going to choose an adapted strategy which is more effortful to use unless you think there's a good outcome as a result of it if it's going to be beneficial to you. Because it's easy to say like go you go blank yourself, right? It's easy. It's easy to just strengthen. extra beer. It's easy to ignore, to suppress, seeing a colleague who's bothering you and just

like walk the other way. Avoidance is easier. Ignoring is easier. Denials is easier. Drinking is easier. Yelling, screaming is easy. Complex problem solving, meditating, you know, takes effort. Listen to the psychology podcast on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts. Okay, Daniel, we're talking about cosmic inflation, which is the new big bang. Should we just call it the big inflationary bang? The biggest bang, maybe. The bangy inflation.

So that's a crazy idea, this idea that the universe went from an infinitely dense infinity to a less infinitely dense infinity in less than 10 to the 20. 26 seconds. That's crazy. It's crazy. But, you know, the universe and reality are no stranger to absurdity. Right. They don't care what your definition of crazy is. Yeah, and crazy stuff has happened.

And that's one of my favorite things about physics is learning that the universe is bonkers, bonkers beyond our imagination sometimes. So it stretches our concept of reality completely. Because my question to you is, why do scientists think that so much happen in such a short amount of time? Basically, why do we think the Big Bang or the inflation happened in the first place? Yeah, well, it solves some problems. It explains some of the things that we see that we can't otherwise resolve. I mean, you might come up with another theory that explains what we see out there, but it has to explain all the stuff that we see and tie up all the loose ends.

And one of the things is what we mentioned earlier on is that we seem to be at the center of the universe. And that doesn't make sense. And in the hot Big Bang model, you have a point that explodes out. but it does explain what we see if the whole universe was infinite and expanded out everywhere at once because then everywhere looks like it's at the center of the universe it's like you're in the middle of a loaf of bread and all the raisins as it's baking all the raisins are moving away from you that's true no matter where you are in this infinite loaf of bread yeah it's like being in a rubber sheet right when you stretch it out wherever you stand it looks like everything's

moving away from you yeah exactly and and that's pretty compelling, but then you might ask, all right, well, that just requires that the universe is infinite and is filled with an infinite amount of stuff. Why do you think it had this crazy expansion? And part of that comes with what we see out there in the universe is that the universe is pretty smooth. I mean, there are clumps, galaxies, and solar systems, and we'll get into that in a moment, but if you average out over it, it looks pretty smooth. And most specifically, if you look at this cosmic microwave background radiation, this light we've talked about, that comes from like 300,000 years after the Big Bang when the universe was a hot plasma.

We see that light, and we use that light to measure sort of the temperature of the universe by the frequency of the light, and it's really, really, really smooth. Like, it looks like the universe was basically the same temperature everywhere, and that's weird. It's very even, right? It's like it all looks the same almost from every direction. Yeah, it looks like a smooth bath. You know, it looks like the temperature varies by one part in 100,000 or one part in 10,000, from here to there to the other place.

And you might be thinking, well, what's weird about that, right? Well, it's weird from the point of view that those things are cosmically far apart. If you look at light that's coming to us from one direction in the cosmic microwave background radiation, it's been traveling the whole history of the universe just got here. If you look from the other direction, life coming from the other direction has also been traveling the whole history of the universe and just got here. So it's the first time they ever met. Right, from different ends of the universe. Right?

One of them came from the left edge of the universe and the other one came from the right edge of the universe. Right. Yeah, well, even if there aren't any edges, they came from totally separated spots, spots that have not had time to talk to each other or communicate in any way since the beginning of the universe. Mm. Right. That's weird. That's weird because they're the same temperature. And the only way you can get stuff to be the same temperature is to let it mix, right?

Like if you put an ice cube into hot water, then you have a cold spot in your water, and you have to wait for things to mix for the temperature to get so even. And so it looks like the universe had a chance to mix. It looks like the temperature smoothed out. But how do that happen? Because these things have never had a chance to talk to each other before. Right. What if it would touch us how the universe was before? It was all even. Yeah, it could be. You know, a lot of these problems are sort of aesthetic. You're like, well, I don't really get it. I don't like that assumption. And so you could say, well, the universe was just created like perfectly smooth. Yeah, it just came off the factory floor, nice and, nice and toasty. Yeah, nice and toasty. It's not exactly smooth. We see little clumps in there. And the distribution of those clumps is another thing. that's explained by inflation.

But you're right, this, you know, by itself, this smoothness problem is not completely bulletproof, right? You could say maybe the universe was just created almost perfectly smooth. Like maybe when photons were created at the beginning, they all have the same temperature. That would be another way to explain it. That would be another way to explain it. But the explanation that comes from inflation is that these things did once have a chance to mix that, you know, before inflation, these photons, which were 10 billion light,

apart, we're only a meter apart. And so there was a lot of time in this early plasma for stuff to slosh around and for things to get smoothed out and for the universe to get to an even temperature before things got inflated. Right. And so I think I remember

this, the way that this explains it is that you need this kind of rapid and violent expansion of space to basically take the left edge photon and the right edge photon far enough apart

where it makes sense now. Yeah. So these two have had to been inside the same sort of cosmic horizon before, and now they're outside the cosmic horizon. Cosmic horizon is something

that is so far away that you have not seen it because light from it has never reached you in the history of the universe. Right. There's like no way they could have talked before,

and yet it seems like they have talked before. And the expansion of space, faster than the speed of light, is the thing that can do that. It can take things that were inside the same cosmic horizon, right, that are close enough to interact and talk to each other and smooth that and become the same temperature and push them apart into their own separate cosmic horizons so that they can no longer interact. And so that's what we think we see now, is that light from this, from two directions in the universe, is now the same temperature,

even though without cosmic inflation, we don't think that they could ever have met. Right. It's like a crazy thing you've seen. universe that can only be explained, apparently, by this crazy idea of inflation. Yeah, precisely. That's one reason why we like inflation. It explains that. And more specifically, the universe is not all the same temperature. If you look at the cosmic microwave background radiation, this light from the early universe, we said it's like the same to within one in 10,000 or one in 100,000. Those wiggles are actually important. Those deviations from being exactly the same temperature are really important.

And we study those really carefully because those are the seeds of the rest of the universe. Right. They're the wrinkles that came from basically this giant stretching of the universe. Yeah, those wrinkles came from the giant stretching. And you might wonder like, all right, say the universe was created perfectly smoothly, like you were saying earlier. Why couldn't just come off the factory floor like totally homogenous? Well, if you have a universe like that, then you never get any. any sort of clumping. You don't get anything like solar systems and hamsters and galaxies and stuff

because everything is perfectly smooth and there's no place where things start to clump together. To get any sort of clumping or structure, you need something that's not homogenous. Right. And so you're saying inflation is our only explanation for why the universe is smooth and clumpy at just the right amount that we see it right now. That's right, because in physics, we have only one way to introduce random clumpiness. And that's quantum mechanics. So the idea is the universe was really, really dense and perfectly smooth. And then quantum fluctuations just like created a few particles here and a few particles there. Now normally, when that happens and it's happening all the time,

it's not a big deal because they're at the quantum level so you don't see them. But what if just when you're making those fluctuations, the universe decides, I'm going to blow this up to 10 billion light years? Then all of a sudden, tiny little quantum fluctuations become really big cosmic fluctuations, right? They become spread out over the whole cosmos. Then they're big enough to seed gravity to get things moving to clump stuff together. Right. And if so if inflation was not as dramatic, then we wouldn't see those quantum fluctuations, right? Because let's say that inflation had actually taken longer than you wouldn't, you know, it wouldn't stretch those quantum fluctuations because things would even

out before you stretch out to what we see now. Yeah, and that's why you need to have inflation happen at the scale that it happened, like so dramatically and so quickly. You've got to catch those quantum fluctuations with their pants down. Otherwise, it doesn't explain

the universe we're in. That's right. Their cosmic embarrassment is the reason why we are here. That's right. That's sort of basically right, right? It's like you needed to catch the universe at just the right time. with this crazy expansion, like this photograph in order to explain what we see now. Yeah, and we talked on the podcast recently about another possibility, another different idea,

which was cosmic strings. People thought, maybe cosmic strings are the reason why we see this sort of distribution of stuff in the universe. But people look to them more carefully and it doesn't work. You don't get the sort of the right kind of wiggles. You don't get the right distribution of stuff here and stuff there. But inflation gets it just right. Inflation says if you had that really dense plasma and you blew it up really quickly, you would expect to get just the right density of stuff to form the kind of structure that we see today.

And there's no other way to explain it in such fine detail that we know of. I mean, there are some other crazier ideas, but none of them work as well as inflation. Right, yeah. Like if inflation had lasted 10 to the negative 31 seconds instead of 10 to the negative 32 seconds, then you and I wouldn't be here. Yeah. Yeah, there'd be some other podcasts. which would be not newly as funny.

It would probably be over quicker. But there's something else there. There's a real randomness, right? Like, it tells you that the structure of the universe, like why there's a galaxy here comes from some like electron fluctuating out of the vacuum 14 billion years ago. And if it had fluctuated in a different direction, we'd have a different galaxy somewhere else.

Like those tiny little quantum rolls of the dye determine the specific structure of our universe today. It's mind-boggling to think about. And they're super sensitive, right? And totally random. Super sensitive and totally random, yeah. Wow. So we are lucky to have the universe we have right now.

And you, listeners, are lucky to have us, frankly. And we are lucky to have you. We are very glad that you fluctuated into existence. We are all lucky to have each other, I think. Is it the new theme for 2020. Okay, cool. I feel like I really understand this a little bit more. You know, it's like this idea.

of an infinite infinity going less dense is, and very quickly, in order to explain what we have now. So does that mean, Daniel, that we know everything about inflation and what happened at the beginning of time, or are there still things we don't know? There's like an infinite amount of stuff that we don't know about inflation. It's an infinitely amount of stuff we don't know

about an infinitely dense infinity that gets less infinite. Yeah, as our knowledge grows, it feels like our ignorance is also growing. Or like our knowledge of our ignorance is inflating as well. You know, but that's a fun part about science. I think the biggest mystery about inflation is like what caused it? What made it happen? What could possibly expand space at this crazy rate?

Right. Like, why didn't the universe just stay the way it was before? Why did it have to have this crazy expansion? Yeah, and why did the expansion stop? And so as usual, we don't have any idea, but we've already given it a name. Oh, of course. Yeah, we've called it the inflaton. It's not a joke.

I know it sounds like I'm making that up, but we created this field called the inflaton field, which would have an inflaton particle, and the idea is that this field causes this crazy expansion. It sort of just puts off the question like, all right, well, what creates the infloton field and what controls it? Well, we have no idea.

But it's just sort of like a place to put our ideas. Interesting. So we owe our existence and our universe to the inflaton. Yeah, and the inflaton, the idea there, is like the universe is filled with this inflaton field, which expands space and sort of decays into ordinary matter. That's how you get ordinary matter. You have inflaton field, which then turns into corks and electrons and other kinds of fields. And we don't know like what would cause that decay.

Like that's when inflation stops is when it turns into normal matter. But we don't know like why would it stop and- Or why was it there in the first place? Yeah, why was it there in first place. And also did it stop? Like, there might be, it might be that inflation sort of stopped in our part of the universe, but it's still going on in other parts of the universe. It could be the rest of the universe.

We're like in a little bubble, a pocket universe, and the rest of the universe is still inflating. And imagine how far, if it got that far in 10 to the minus 32 seconds, imagine what it could do in 14 billion years. Wow. So you're saying that maybe we are even more insignificant than we had previously imagined. Yeah, that's this idea. It's called eternal inflation that the universe is continuously inflating, and that occasionally

the inflation sort of decays into normal matter, and then you get the kind of universe we're familiar with, but that most of the universe is just this massively expanding inflaton field. Wait, are you saying, Daniel, that the inflaton works in mysterious ways? I'm saying exactly that. Mostly because we don't understand it at all, and so... Can I start a new religion based on the inflaton? Are you the high priest of the inflation period?

I am because I am both a high priest and the parishioner of my Church of the Inflaton. Yes, please donate to the Church of the Inflaton. I think we just replaced the Spaghetti Master. Yeah. And so, of course, this feels like a big placeholder because it is. We don't know. And so it's just a way to say if inflation happened, what's a possible way it might have happened? And then let's start to get to work on figuring out how that theory has to look.

Step one, give it a sciencey name. That's right. And then figure it out. Step two, get ridiculed by Jorge. Step three, get to work. All right, cool. It sounds like there's still lots of answers to be found in this. And these are important answers, right?

I mean, they're about the beginning of the universe and why are things the way they are and are things going to change in the future? And, you know, I think in 10 years or in 20 years, people will look back at these ideas and think, oh, my gosh, how absurd. I can't believe they really believe that stuff. because we're going to learn things about inflation and we're going to learn things about the history of the universe and its current expansion that are going to give us better ideas,

even crazier ideas that are going to be even more correct. And so this is the perfect example of how our knowledge of the universe is constantly expanding. We look back and think, wow, how silly. Yeah, you know, they say 2020 smart physicists are 2030s, ignoratons. That's right. Yep. I have 2020 vision, which means I look back at 2020.

10 and think, what a bunch of idiots. Well, I can't wait to have 20, 30 vision. That's what happens in our old age, right? We all get reading the masses. All right. Well, maybe we'll get into these mysteries a little bit deeper in a future podcast. But for now, thanks for joining us. We hope you enjoyed that.

We hope we inflated your mind and took you on a tour of the early universe. Thank you very much. If you still have a question after listening to all these explanations, please drop us a line we'd love to hear from you. You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge, that's one word, or email us at Feedback at danielandhorpe.com. 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. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, everything changed. There's been a bombing at the TWA terminal.

Just a chaotic, chaotic scene. In its wake, new kind of enemy emerged. Terrorism. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Why are TSA rules so confusing? You got a hood of you.

I'll take it all! I'm Manny. I'm Noah. This is Devin. And we're best friends and journalists with a new podcast called No Such Thing, where we get to the bottom of questions like that. Why are you screaming at me? I can't expect what to do.

Now, if the rule was the same, go off on me, I deserve it. You know, lock him up. Listen to No Such Thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. No such thing. I'm Dr. Joy Hardin Bradford, host of the Therapy for Black Girls podcast. I know how overwhelming it can feel if flying makes you anxious. In session 418 of the Therapy for Black Girls podcast, Dr. Angela Nealbornett and I discuss flightings. What is not a norm is to allow it to prevent you from doing the things that you want to do, the things that you were meant to do.

Listen to therapy for black girls on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. This is an IHeart podcast.