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

• 0:08
  Speaker 1: Hey, Daniel, did you have a good holiday break? Oh?
• 0:12
  Speaker 1: I did, but you know, as usual, I ate too much.
• 0:15
  Speaker 1: You mean you ate cosmically too much? Yeah, I totally
• 0:19
  Speaker 1: overdid it. I'm like on the verge of becoming a
• 0:21
  Speaker 1: black hole myself. Would you say your waistline is inflating,
• 0:28
  Speaker 1: I'd say a few more bites and I'd be risking
• 0:30
  Speaker 1: becoming my own personal big bang big Daniel. I'm talking
• 0:36
  Speaker 1: dark matter here people. Oh no, let's cut to the
• 0:40
  Speaker 1: theme song. Cut to the theme song. Hi am or
• 0:58
  Speaker 1: handmade cartoonist and the creator of PhD comics. Hi, I'm Daniel,
• 1:03
  Speaker 1: I'm a particle physicist, and I am actually full of
• 1:06
  Speaker 1: dark matter. Welcome to our podcast, Daniel and Jorge Explain
• 1:10
  Speaker 1: the Universe, a production of I Heart Radio in which
• 1:13
  Speaker 1: we examine all things fascinating and amazing and bonkers about
• 1:17
  Speaker 1: our universe and explain them to you in a way
• 1:19
  Speaker 1: that you can actually understand. So it's a new decade here,
• 1:23
  Speaker 1: and so, Daniel, what do we have to look forward
• 1:25
  Speaker 1: to in physics? What do we have to look forward
• 1:27
  Speaker 1: to in physics? Wow? So much? There are all sorts
• 1:30
  Speaker 1: of new exciting telescopes coming online that will let us
• 1:34
  Speaker 1: see further and further into the ancient past. The Large
• 1:37
  Speaker 1: Hadron Collider is going to keep running and maybe discover
• 1:40
  Speaker 1: some crazy new particles. But you know the best thing
• 1:43
  Speaker 1: about looking forward in physics is that we have no
• 1:45
  Speaker 1: idea what we're going to discover. There are always surprises
• 1:48
  Speaker 1: out there waiting for us. There are surprises everywhere. Yeah,
• 1:51
  Speaker 1: that's awesome. Yeah there might be Hey, a new kind
• 1:54
  Speaker 1: of plantain or a strawberry flavored banana discovered by scientists somewhere.
• 1:58
  Speaker 1: You never know science. It's what's for dinner, and so
• 2:04
  Speaker 1: there's a lot of good stuff to look forward to.
• 2:06
  Speaker 1: I look forward to in looking back and thinking, Man,
• 2:10
  Speaker 1: those folks in had no idea what was coming. Interesting.
• 2:14
  Speaker 1: You look forward to the future so you can laugh
• 2:16
  Speaker 1: at the past. Yeah, it's a wonderful feeling to think,
• 2:20
  Speaker 1: look at what we know about the universe, and look
• 2:23
  Speaker 1: at how the people before us, including ourselves ten years ago,
• 2:27
  Speaker 1: really had no clue what was coming. And that's exciting
• 2:29
  Speaker 1: to me because it makes me enthusiastic about the next
• 2:32
  Speaker 1: ten years. You know, the mind blowing discoveries that physics
• 2:35
  Speaker 1: and the rest of science will reveal. Man, you're making
• 2:38
  Speaker 1: me feel bad about humans. They were so clueless, oh man,
• 2:44
  Speaker 1: with their like new Facebook craze and they didn't even
• 2:47
  Speaker 1: have TikTok or Instagram. No, but we learned a lot
• 2:51
  Speaker 1: about the universe in the twenty tens. You know, we
• 2:55
  Speaker 1: saw a whole bunch of new exo planets and discovered
• 2:58
  Speaker 1: the Higgs boson, and you are there really some pretty
• 3:01
  Speaker 1: big shifts that our understanding of the universe in the
• 3:03
  Speaker 1: last ten years. And since science is just accelerating exponentially,
• 3:07
  Speaker 1: then I look forward to even more mind blowing stuff
• 3:10
  Speaker 1: in the decade to come. Yeah, and technically we have
• 3:13
  Speaker 1: more universe now than we had in Right, the universe
• 3:17
  Speaker 1: is constantly expanding and getting bigger. There's new space being created,
• 3:22
  Speaker 1: so we have also that to look forward to. Right
• 3:24
  Speaker 1: in the future, there there will be even more space.
• 3:27
  Speaker 1: That's right, in the future, you will occupy a smaller
• 3:30
  Speaker 1: fraction of the universe because the universe is inflating. Oh no, wait,
• 3:35
  Speaker 1: so you're saying that the people in were more significant
• 3:38
  Speaker 1: than we are. Well, you know, what's the fraction of
• 3:42
  Speaker 1: infinity is still zero so relatively speaking. But you know,
• 3:45
  Speaker 1: I had a listener right in and make a really
• 3:47
  Speaker 1: fascinating point about the expansion of the universe that I
• 3:50
  Speaker 1: had never thought of before. Yeah, And they said, well,
• 3:54
  Speaker 1: what about in time travel books, if you go back
• 3:57
  Speaker 1: in time, then doesn't your body occupy a smaller space
• 4:01
  Speaker 1: in the universe back then than it does now? And
• 4:05
  Speaker 1: how do you account for that? And it's true, you know,
• 4:08
  Speaker 1: the space that you occupied twenty years ago has expanded
• 4:12
  Speaker 1: to a larger space, and so somehow you have to
• 4:15
  Speaker 1: factor that into your time travel novel. WHOA like if
• 4:18
  Speaker 1: you if you send your consciousness back, it has to
• 4:21
  Speaker 1: somehow fit into a smaller package or something. Yeah, it
• 4:25
  Speaker 1: has to shrink exactly. You gotta squeeze your way back
• 4:28
  Speaker 1: into the universe from ten years ago or twenty years ago.
• 4:31
  Speaker 1: On today's episode, we are going to not look forward
• 4:34
  Speaker 1: in time, but we're going to try to look backwards
• 4:37
  Speaker 1: in time almost as much as you can look backwards. Right,
• 4:40
  Speaker 1: that's right. We're gonna try to rewind all the way
• 4:42
  Speaker 1: back to the very beginning. Because I've noticed that in
• 4:46
  Speaker 1: conversations with listeners and just with folks around campus, that
• 4:49
  Speaker 1: there's still a lot of misunderstandings about the very beginning
• 4:52
  Speaker 1: of the universe. Right, because right now we have a
• 4:55
  Speaker 1: lot of space, there's a lot of universe, but at
• 4:57
  Speaker 1: some point in the past there was very little of
• 5:00
  Speaker 1: the universe. I don't know. I mean, I think right
• 5:03
  Speaker 1: now the universe is pretty dilute, but in the past,
• 5:07
  Speaker 1: the universe was more dense. It could be that the
• 5:09
  Speaker 1: universe has been infinite since its conception. So in that sense,
• 5:13
  Speaker 1: it doesn't really make sense to talk about having less universe.
• 5:16
  Speaker 1: It's just more compact, right, A denser infinity, yes, a
• 5:20
  Speaker 1: denser infinity exactly, versus a water down infinity, which you know,
• 5:26
  Speaker 1: it just doesn't taste as good. That's right. But I
• 5:29
  Speaker 1: think a lot of people when you talk about the
• 5:31
  Speaker 1: beginning of the universe and the Big Bang, they have
• 5:34
  Speaker 1: sort of an old idea in their head of what
• 5:36
  Speaker 1: the Big Bang was like this just this big explosion
• 5:38
  Speaker 1: from a singularity, and that's not really the modern view. Wait,
• 5:42
  Speaker 1: you're saying the name big bang doesn't actually describe the
• 5:45
  Speaker 1: Big Bang. I think it was pretty big and it
• 5:48
  Speaker 1: might have been a bang, so you know, from that
• 5:51
  Speaker 1: point of view. But I think the ideas in people's
• 5:53
  Speaker 1: heads need updating. I see, it's it's a kind of
• 5:56
  Speaker 1: big bang, yes, exactly. Big Bang and compass is like
• 6:00
  Speaker 1: a whole spectrum of ideas and physics has moved on,
• 6:04
  Speaker 1: while popular conception is sort of stuck in the eighties version, right,
• 6:08
  Speaker 1: And so this is a question that you said to me.
• 6:11
  Speaker 1: A lot of listeners asked wrote in to ask about
• 6:14
  Speaker 1: a lot of people are wondering and asking us to
• 6:16
  Speaker 1: explain what this idea is. Yeah, and so, as usually,
• 6:20
  Speaker 1: we want to cater to our listeners. We want to
• 6:21
  Speaker 1: answer the questions that are in your minds, and we
• 6:24
  Speaker 1: want to bring you to the forefront of science. We
• 6:26
  Speaker 1: want you to understand what scientists out there, who are
• 6:29
  Speaker 1: experts in this field, who know the most that any
• 6:32
  Speaker 1: human is ever known about the beginning of the universe,
• 6:34
  Speaker 1: what they are thinking about. We want to explain it
• 6:37
  Speaker 1: to you in a way that makes sense. So that's
• 6:39
  Speaker 1: our goal. So today on the episode, we'll be asking
• 6:41
  Speaker 1: the question, what is cosmic inflation? Inflation? Inflation? That's right,
• 6:54
  Speaker 1: it's not controlled by the Federal Reserve. It's not the
• 6:56
  Speaker 1: reason why your bank account is emptying. Wait, you mean
• 7:00
  Speaker 1: cosmic interest rate? Don't don't make a difference here. No,
• 7:03
  Speaker 1: we can't borrow money from the other universe. Orything can
• 7:07
  Speaker 1: my cosmic debt somehow bring it down? That's your karmic debt, actually,
• 7:11
  Speaker 1: and there's nothing you can do about that. Then do
• 7:15
  Speaker 1: good things for people, like explain the universe to them.
• 7:18
  Speaker 1: I think that's definitely a positive on the karmic debt,
• 7:21
  Speaker 1: right right, But today we're talking about cosmic inflation, and
• 7:25
  Speaker 1: that kind of sounds simple. It just means that the
• 7:27
  Speaker 1: cosmos is getting bigger or got bigger. But in this case,
• 7:32
  Speaker 1: scientists use this phrase for something very specific, right, like
• 7:35
  Speaker 1: a very specific moment in time right after the Big Bang.
• 7:41
  Speaker 1: Sort Of, it's both a specific moment in time that's
• 7:44
  Speaker 1: after the Big Bang, it's also sort of our modern
• 7:47
  Speaker 1: view of what the Big Bang was, and and it's
• 7:51
  Speaker 1: also connects the like primordial inflation, these first moments when
• 7:57
  Speaker 1: the universe is expanding with the current inflation, and it
• 8:00
  Speaker 1: says maybe these things are connected. So it's sort of
• 8:03
  Speaker 1: like saying the Big Bang wasn't the moment of creation.
• 8:06
  Speaker 1: It happened just afterwards. And it's saying maybe the Big
• 8:09
  Speaker 1: Bang is still banging. We're still banging, yes, exactly, that's
• 8:13
  Speaker 1: how big this bang is. Well, it sounds like it's
• 8:17
  Speaker 1: it's pretty interesting and maybe there are a lot of
• 8:20
  Speaker 1: subtle ideas here, so we'll get into all of that.
• 8:22
  Speaker 1: But first, as usual, we were wondering how many people
• 8:24
  Speaker 1: out there heard of the phrase cosmic inflation and if
• 8:28
  Speaker 1: they knew what it was. That's right. And so since
• 8:31
  Speaker 1: it was winter break and you see, Irvine was closed,
• 8:34
  Speaker 1: I walked around coffee shops in Irvine and I asked
• 8:37
  Speaker 1: random strangers who were amenable to being interrogated about physics
• 8:42
  Speaker 1: topics while on their holiday break if they knew anything
• 8:46
  Speaker 1: about cosmic inflation. Here's what they had to say. Oh,
• 8:49
  Speaker 1: I feel like I've heard the term, but I do
• 8:50
  Speaker 1: not know what it means. Um, cosmic inflation is that
• 8:56
  Speaker 1: like the theory where everything in space is like constantly
• 8:59
  Speaker 1: moving away from itself, like there's an explosion and everything's
• 9:04
  Speaker 1: still expanding. Yeah, I have no idea. I think it
• 9:08
  Speaker 1: means that just like crowding together, maybe like everything's coming together,
• 9:12
  Speaker 1: but I don't know. The universe is expanding and getting
• 9:17
  Speaker 1: bigger with each but as time passes, so something that's
• 9:21
  Speaker 1: happening now or in the past, it's still happening from
• 9:25
  Speaker 1: the universe. That's something that's happening now or in the
• 9:28
  Speaker 1: beginning the universe, or it's always been happening. Yes, what
• 9:31
  Speaker 1: is it? That's essentially the basis of the big bank theory? Okay, Um,
• 9:35
  Speaker 1: when did it happen fourteen point three billion years ago?
• 9:39
  Speaker 1: We might have more more satellites of space, space stations
• 9:44
  Speaker 1: or something. I have no idea. I mean it sounds
• 9:47
  Speaker 1: like the expansion of space, cosmic inflation. No, alright, a
• 9:51
  Speaker 1: lot of knows I feel, not a lot of inflated
• 9:55
  Speaker 1: answers here. No, no, no, and confusion people thinking like
• 10:01
  Speaker 1: space is getting smaller or the Earth is getting more crowded.
• 10:05
  Speaker 1: That maybe they thought space was getting devalued. Maybe there's
• 10:10
  Speaker 1: the there's the negative flip side to it that surprised.
• 10:13
  Speaker 1: The market for space is sad oversaturated. So better spend
• 10:17
  Speaker 1: your space now before it's worth nothing. Better use it up. Better,
• 10:22
  Speaker 1: eat more so you can take up more space. That's
• 10:25
  Speaker 1: that's my New Year's resolution. Eat more dark matter, take
• 10:28
  Speaker 1: up more space, make more dark better. But there were
• 10:33
  Speaker 1: some some core ideas here. You know, people have heard
• 10:36
  Speaker 1: of some connection to the Big Bang or some ideas
• 10:39
  Speaker 1: for things that happened in the early universe. So there's
• 10:41
  Speaker 1: definitely some nuggets there Yeah. A lot of people said
• 10:43
  Speaker 1: it related to the expansion of the universe, which is
• 10:46
  Speaker 1: I guess not a big stretch, right. Inflation and expansion
• 10:49
  Speaker 1: sort of sound the same. Yeah, And in fact I
• 10:51
  Speaker 1: think they're right. It is related to the expansion of
• 10:53
  Speaker 1: the universe as far as we know, which is not
• 10:56
  Speaker 1: very much, it turns out, you know, and this is
• 10:58
  Speaker 1: fascinating to me because it's something where we've made a
• 11:01
  Speaker 1: lot of progress in the last twenty years coming up
• 11:03
  Speaker 1: with new, crazy ideas about the universe, but something that
• 11:06
  Speaker 1: we're also still puzzled over, Like there are huge unanswered
• 11:10
  Speaker 1: questions about the Big Bang and cosmic inflation. There are
• 11:13
  Speaker 1: things that scientists are arguing about. You know, the guy
• 11:16
  Speaker 1: who came up with inflation, one of the architects of
• 11:19
  Speaker 1: the theory, Paul Steinhardt, is now the guy arguing against
• 11:22
  Speaker 1: the theory most Yeah, he's trying to deflate inflation, that's right.
• 11:27
  Speaker 1: He's trying to pop the bubble of his own creation.
• 11:30
  Speaker 1: So what's interesting I think is that, you know, if
• 11:32
  Speaker 1: you had asked what is the Big Bang, a lot
• 11:34
  Speaker 1: of people might have said, yes, it has had some
• 11:36
  Speaker 1: ideas about that. It's about the beginning of the universe,
• 11:39
  Speaker 1: but cosmic inflation, which is almost as important, doesn't have
• 11:42
  Speaker 1: the same kind of market recognition. Yeah, and that's what
• 11:45
  Speaker 1: we're going to try to correct today on the podcast.
• 11:48
  Speaker 1: We're gonna bring some panash to cosmic inflation. We're gonna
• 11:51
  Speaker 1: show people how big bang is sort of the old
• 11:54
  Speaker 1: busted theory and cosmic inflation is the new hotness. M
• 11:58
  Speaker 1: it's a new bang. It's the new bang. That's right
• 12:01
  Speaker 1: out with the old bang, in with it's climb. Are
• 12:06
  Speaker 1: you still banging the old way? Man? What's wrong with you? Try?
• 12:11
  Speaker 1: Are you physics bace banging? Yeah? I don't know what
• 12:16
  Speaker 1: advertisers are going to go for that. Somebody out there
• 12:19
  Speaker 1: has got a product that fits that. Alright, Diana, So
• 12:23
  Speaker 1: let's get into it. Let's get into this idea of
• 12:25
  Speaker 1: cosmic inflation. So, first of all, what is how would
• 12:28
  Speaker 1: you define inflation in a physics way? Basically, inflation is
• 12:34
  Speaker 1: the expansion of space. It's saying, let's take space and
• 12:38
  Speaker 1: stretch it. Let's make space bigger and it it's important
• 12:42
  Speaker 1: there to understand that it's not the moving of stuff
• 12:44
  Speaker 1: through space. It's really the stretching of space itself. So
• 12:49
  Speaker 1: are we stretching space or creating new space both both.
• 12:52
  Speaker 1: That is how you stretch spaces and you create new space.
• 12:56
  Speaker 1: I see, like there's more meters. It's not like the
• 12:58
  Speaker 1: meter got bigger, so it's just more meters of space. Yeah,
• 13:01
  Speaker 1: there are more meters of space. So stuff can be
• 13:04
  Speaker 1: further apart without moving through space. Right. It's like if
• 13:08
  Speaker 1: you take a ruler and you put a penny on
• 13:11
  Speaker 1: the one meter and on the two m and then
• 13:13
  Speaker 1: you stretch the ruler. The ruler itself is like may
• 13:16
  Speaker 1: out of elastic, and you stretch the rulers to make
• 13:19
  Speaker 1: it longer than the two pennies are further apart even
• 13:22
  Speaker 1: though they haven't moved relative to the ruler. That's expansion
• 13:26
  Speaker 1: of space. That's inflation of space. Right. But it's not
• 13:30
  Speaker 1: just that the ruler expanded. It's like the wood of
• 13:32
  Speaker 1: the ruler got bigger. You definitely add more to the ruler. Okay,
• 13:36
  Speaker 1: And so that's different than kind of the old idea
• 13:39
  Speaker 1: of how the Big Bank happened after the beginning of time. Yeah,
• 13:44
  Speaker 1: so let's dig into that in that way. Let's like
• 13:47
  Speaker 1: define what I think most people think the Big Bang
• 13:50
  Speaker 1: was and the sort of old idea of what the
• 13:52
  Speaker 1: universe was, and then let's contrast it with with sort
• 13:55
  Speaker 1: of what they should replace in their heads with. Okay,
• 13:57
  Speaker 1: so what's the old thing. The old thing, I think
• 14:00
  Speaker 1: is this idea that the universe started from a point
• 14:03
  Speaker 1: like a singularity and infinitely dense dot primordial atom, which
• 14:08
  Speaker 1: was a point in space. It was like somewhere and
• 14:10
  Speaker 1: it was infinitely dense. And remember, like nobody has in
• 14:14
  Speaker 1: the idea where this thing might have come from, what
• 14:16
  Speaker 1: could have created it. But that's sort of just like
• 14:18
  Speaker 1: swept under the rug, you know, the primordial rug, Like well,
• 14:21
  Speaker 1: you know, we don't know what came before, but let's
• 14:23
  Speaker 1: just start from there. Right, it was like a little tiny,
• 14:25
  Speaker 1: infinitely energetic package in sitting in space actually right like
• 14:30
  Speaker 1: it was. People think it was like a grenade sitting there.
• 14:33
  Speaker 1: It was really really small, exactly, And that's really key
• 14:36
  Speaker 1: insight there that space was already created. You already had space,
• 14:39
  Speaker 1: and you just had this dot in space. And then
• 14:41
  Speaker 1: it exploded and that stuff then flew out and it
• 14:45
  Speaker 1: spread out and slowly got more and more dilute, right
• 14:49
  Speaker 1: less dense like an explosion would, and spread out to
• 14:53
  Speaker 1: eventually form of the universe, and that's the stuff moving
• 14:57
  Speaker 1: through space. And that's what we call in science the
• 14:59
  Speaker 1: hot big Bang model. The hot big Bang is now
• 15:02
  Speaker 1: the old Big Bang. It's right, you know, it's like
• 15:05
  Speaker 1: your ex girlfriend and boyfriends. You still think they're hot,
• 15:07
  Speaker 1: but it's not really for you anymore. Man. So that's
• 15:11
  Speaker 1: probably the idea most people have in their heads when
• 15:14
  Speaker 1: you say big bang or creation in the universe. And
• 15:17
  Speaker 1: I think that's what I thought that the Big Bang was,
• 15:20
  Speaker 1: you know, way before, when I was in high school
• 15:22
  Speaker 1: or before I started hanging out with physicists, was that
• 15:25
  Speaker 1: the Big Bang is really just like a bang, Like
• 15:28
  Speaker 1: everything that we know about was in a small spot
• 15:30
  Speaker 1: and then it just exploded. And now all the stars
• 15:32
  Speaker 1: and galaxies and dust that was in that little bit
• 15:34
  Speaker 1: doot are now flying through space outwards. Yeah. And you know,
• 15:38
  Speaker 1: when you started hanging out with physicists, basically the moment
• 15:41
  Speaker 1: your universe was created. Everything else before that is like, oh,
• 15:45
  Speaker 1: waste of time. I see you. You created my universe, Daniel,
• 15:51
  Speaker 1: my universe started. There's nothing before I met you. There
• 15:54
  Speaker 1: you're supposed to go with you complete my universe. You're
• 15:58
  Speaker 1: saying you made my universe. Then that's even more romantic. Wow.
• 16:02
  Speaker 1: Well all right, yeah, I think on the back pedal
• 16:04
  Speaker 1: on that a little bit, But no, you're right, and
• 16:06
  Speaker 1: I think that's what most people think um as sort
• 16:09
  Speaker 1: of how the universe began, and you know, there's lots
• 16:11
  Speaker 1: of questions there um. But one big problem with that
• 16:14
  Speaker 1: conception is that it has a center, has a place
• 16:17
  Speaker 1: where the Big Bang happened. And if you were looking
• 16:20
  Speaker 1: at the explosion from any point of view, you would
• 16:23
  Speaker 1: see stuff sort of flying sideways, unless you happen to
• 16:26
  Speaker 1: be at the center, then everything would be flying in
• 16:29
  Speaker 1: a certain direction, right, and you could tell maybe where
• 16:32
  Speaker 1: the center of the universe was just by looking at
• 16:35
  Speaker 1: where all the things were, and you're flying away from
• 16:38
  Speaker 1: precisely and as a foreshadowing moment, that's not what we
• 16:42
  Speaker 1: see when we look out into space. Yeah. So at
• 16:45
  Speaker 1: some point a humanity physicist and scientists decided or started
• 16:50
  Speaker 1: to realize that this old model of the big band
• 16:53
  Speaker 1: was not the right one. Yeah. I mean it's a
• 16:56
  Speaker 1: good first draft. Like we're thinking about the universe, is
• 16:59
  Speaker 1: expanding what could have created it. You know, we don't
• 17:01
  Speaker 1: want to criticize those scientists, is being dumb or something
• 17:04
  Speaker 1: It's just sort of like science evolves, and this is
• 17:06
  Speaker 1: how it evolves. You have an idea, you compare it
• 17:08
  Speaker 1: to what you see. Doesn't quite work, so you improved
• 17:11
  Speaker 1: the idea. Right, They did a bang up job. It
• 17:16
  Speaker 1: was a big project. But but what I guess what
• 17:19
  Speaker 1: I mean is it at what point did we start
• 17:21
  Speaker 1: to sort of realize maybe this view was not the
• 17:24
  Speaker 1: correct one. Well, there's been a lot of problems with
• 17:27
  Speaker 1: the Big Bang basically since early on. You know when
• 17:30
  Speaker 1: ed when Hubble looked out into the universe and realized
• 17:33
  Speaker 1: it's like a hundred years ago that the universe was expanding,
• 17:37
  Speaker 1: That's sort of what gave birth to this concept of
• 17:39
  Speaker 1: a big Bang. He's the one who discovered that everything
• 17:42
  Speaker 1: was moving away from us, and everything was moving away
• 17:45
  Speaker 1: from us sort of the same speed in every direction
• 17:47
  Speaker 1: you looked. So this is an outstanding problem for the
• 17:50
  Speaker 1: Big Bang for a long time, and it wasn't until
• 17:54
  Speaker 1: this idea of inflation came along that it helped solve it.
• 17:57
  Speaker 1: So the Big Bang was not like totally accepted for
• 18:01
  Speaker 1: many many decades. And one problem what with it was,
• 18:04
  Speaker 1: you know, are we at the center? Why does it
• 18:06
  Speaker 1: look like we are at the center. Oh, I see.
• 18:09
  Speaker 1: He tried to figure out where the center of the
• 18:12
  Speaker 1: grenade was, and so he looked around and he found
• 18:15
  Speaker 1: that the center was us, which is weird, which was like,
• 18:18
  Speaker 1: too coincidental. It's too coincidental. Any time in science you
• 18:22
  Speaker 1: appear to be at the center of the universe, you
• 18:23
  Speaker 1: gotta wonder my biased or I'm just thinking about this wrong.
• 18:28
  Speaker 1: You know, you want to avoid coincidences. You want to
• 18:31
  Speaker 1: avoid things that are really unlikely, or especially things that
• 18:35
  Speaker 1: put humanity in the very important place in the cosmos.
• 18:38
  Speaker 1: Because we've made that mistake before, right, Like before we thought,
• 18:42
  Speaker 1: we like the Earth with decent was the center of
• 18:44
  Speaker 1: the Solar system. More than that, we thought it was
• 18:46
  Speaker 1: the center of the cosmos, right without everything was created
• 18:49
  Speaker 1: around the Earth, Yeah, right, right, And then it turns
• 18:52
  Speaker 1: out that the Sun, not even the Sun, is the
• 18:54
  Speaker 1: center of the universe. It's like just one star in
• 18:58
  Speaker 1: the rotating galaxy, which is part of something even bigger. Yeah,
• 19:02
  Speaker 1: And we like to think more democratically now. We like
• 19:04
  Speaker 1: to think that every point in space is equal, not
• 19:07
  Speaker 1: because they're voting or anything, but just that you know,
• 19:10
  Speaker 1: there should be no special locations because special locations require
• 19:13
  Speaker 1: special explanations. It just makes the most sense if everywhere
• 19:17
  Speaker 1: in space follows the same rules and is the same.
• 19:20
  Speaker 1: And that's why I like the Big Bang is a
• 19:21
  Speaker 1: point never really made sense to me, because then you
• 19:23
  Speaker 1: can always ask, like, well, why they're why did the
• 19:26
  Speaker 1: Big Bang start there and not like a meter over
• 19:28
  Speaker 1: or over there or a light year in the other direction,
• 19:31
  Speaker 1: why they're nowhere else? And so you avoid those questions
• 19:34
  Speaker 1: if you say, everywhere in the universe is the same.
• 19:36
  Speaker 1: All right, So that's the old bang, the old hot bang,
• 19:40
  Speaker 1: and now let's talk about the new hotter bang, I guess,
• 19:43
  Speaker 1: and in terms of trendiness um and why why we
• 19:47
  Speaker 1: think it happened and why is it still a mystery?
• 19:49
  Speaker 1: But first let's take a quick break. Okay, So Danny
• 20:06
  Speaker 1: telling me that the universe, the Big Bang is not
• 20:09
  Speaker 1: like a grenade that exploded that was full stuff and
• 20:11
  Speaker 1: then exploded, But the universe, the Big Bang is actually
• 20:14
  Speaker 1: something different where new space is being created and space
• 20:18
  Speaker 1: is being stretched. It's not an explosion, that's right. And
• 20:22
  Speaker 1: we still have to reconcile the fact that we think
• 20:24
  Speaker 1: the universe was more dense in the past than it
• 20:27
  Speaker 1: is today, and that makes you want to go to
• 20:29
  Speaker 1: the explosion explanation because you know, like, how else could
• 20:32
  Speaker 1: it happen? Right, because the grenade was denser before the explosion,
• 20:38
  Speaker 1: So you might be tempted to apply to our universe. Yeah,
• 20:41
  Speaker 1: So another approach and a better way to think about
• 20:44
  Speaker 1: it that it requires swallowing a really big idea, is
• 20:48
  Speaker 1: that the Big Bang essentially happened everywhere all at once.
• 20:53
  Speaker 1: That the universe wasn't created as a tiny singularity which
• 20:56
  Speaker 1: then exploded, but that the entire uni verse, an infinite
• 21:01
  Speaker 1: universe filled with an infinite amount of stuff, was created somehow,
• 21:06
  Speaker 1: we don't know how, in a very dense state, and
• 21:09
  Speaker 1: the Big Bang was the expansion of that state, the
• 21:12
  Speaker 1: stretching of space itself to make that stuff more dilute.
• 21:16
  Speaker 1: But that it was created everywhere and happened everywhere all
• 21:19
  Speaker 1: at once. So like that's an infinitely big bang. Okay,
• 21:23
  Speaker 1: So you're saying that the universe was has always been infinite.
• 21:26
  Speaker 1: It's not like it started as a point and became
• 21:28
  Speaker 1: exploited into infinity. You're saying that the universe was always infinite,
• 21:33
  Speaker 1: but that before it was like a dance and compact
• 21:35
  Speaker 1: infinite infinity but now it's more of a bigger and
• 21:40
  Speaker 1: more expanded infinity. Precisely, that's the idea. And of course
• 21:43
  Speaker 1: we don't know the size of the universe, and we
• 21:46
  Speaker 1: don't even know it's shape, but this is the idea.
• 21:48
  Speaker 1: It explains what we see, an infinite universe created infinitely
• 21:52
  Speaker 1: big and always filled with an infinite amount of stuff.
• 21:55
  Speaker 1: There's no edge to the matter, and there's no edge
• 21:58
  Speaker 1: to the universe, and just started out really hot and
• 22:01
  Speaker 1: dense and then stretched out right, But that's only one possibility, right,
• 22:06
  Speaker 1: that it's infinite. It could also be that the universe
• 22:08
  Speaker 1: is finite as far as we know. Right, it could
• 22:11
  Speaker 1: be right, but it at least has to be big
• 22:13
  Speaker 1: enough to fill our observable universe with a homogeneous stuff. Right.
• 22:18
  Speaker 1: If there is an edge to the stuff in the universe,
• 22:22
  Speaker 1: we don't see that, and so it has to be
• 22:24
  Speaker 1: really really big and and pretty uniform, at least in
• 22:27
  Speaker 1: our neighborhood. So it's possible that there's an edge to
• 22:31
  Speaker 1: the stuff in the universe. But it's sort of simpler somehow.
• 22:34
  Speaker 1: It's weird. It's weird. It's simpler to imagine an infinite
• 22:37
  Speaker 1: universe with infinite stuff because then you don't have to
• 22:39
  Speaker 1: explain the edges. Even though I can't explain how you
• 22:43
  Speaker 1: create an infinite universe with an infinite amount of stuff
• 22:45
  Speaker 1: in it either, well, nobody can explain it finite universe either. Right,
• 22:50
  Speaker 1: All this stuff defies explanation. But you know it's it's
• 22:52
  Speaker 1: like pushing the rock further up the hill. You don't
• 22:55
  Speaker 1: have to have the answer to every question. You just
• 22:58
  Speaker 1: have to ask have the answer to this question in
• 23:00
  Speaker 1: and then it gives you the next question. Like if
• 23:02
  Speaker 1: you say, let's assume the universe started infinitely large, filled
• 23:06
  Speaker 1: with an infinite amount of stuff, then what would have happened?
• 23:09
  Speaker 1: And you can show that that's consistent with what we
• 23:11
  Speaker 1: see so far, then you get to go back to
• 23:13
  Speaker 1: that other question, say, okay, let's roll up our sleeves
• 23:15
  Speaker 1: and figure out how it's possible to create an infinite universe. Um.
• 23:19
  Speaker 1: So that is that your approach to teaching as well, Daniel,
• 23:22
  Speaker 1: Just make it up as you go along, push all
• 23:25
  Speaker 1: the problems off until tomorrow. That's my approach to life.
• 23:28
  Speaker 1: Yes to my inbox as well. Yeah, and so the
• 23:34
  Speaker 1: idea is you create an infinite universe filled with an
• 23:38
  Speaker 1: infinite amount of stuff, but it's very hot and dense. Right,
• 23:41
  Speaker 1: it's like a huge singularity essentially. Okay, so I think
• 23:44
  Speaker 1: you're saying that the best way to think about the
• 23:46
  Speaker 1: big band it's not as like a little point that exploded,
• 23:49
  Speaker 1: but just as an infinity going from a really dense
• 23:52
  Speaker 1: infinity to a bigger infinity. Yeah, And that's what cosmic
• 23:57
  Speaker 1: inflation is, is taking that really dense um infinity and
• 24:02
  Speaker 1: stretching it out to a much more dilute infinity, because
• 24:06
  Speaker 1: that is what we see, that's what we have evidence for, right,
• 24:09
  Speaker 1: Like we see that the universe is really sparse and
• 24:12
  Speaker 1: I'm kind of empty now, and and we see that
• 24:15
  Speaker 1: everything used to be much much denser. Yeah, we need
• 24:19
  Speaker 1: to have inflation order to explain a bunch of stuff
• 24:21
  Speaker 1: that we see in the universe. And we can get
• 24:24
  Speaker 1: into that in a few minutes if you like. But
• 24:26
  Speaker 1: this explains why the universe looks the way that it does.
• 24:30
  Speaker 1: And without inflation, the universe doesn't really make sense. Like
• 24:34
  Speaker 1: if you just create the universe at this current density
• 24:38
  Speaker 1: and said it expanding now um ten billion years ago,
• 24:42
  Speaker 1: it wouldn't make sense. It doesn't explain what we see.
• 24:44
  Speaker 1: So you need to have this inflationary period in order
• 24:47
  Speaker 1: to get all the sort of the clumpiness and the
• 24:49
  Speaker 1: structure that we see in the temperature of stuff all correct. Okay,
• 24:52
  Speaker 1: So I think that's another key concept about inflation, which
• 24:55
  Speaker 1: is that it's not you know, the universe went from
• 24:59
  Speaker 1: a as infinity to a wider infinity, but it didn't
• 25:03
  Speaker 1: do it sort of evenly, right, like there were there
• 25:06
  Speaker 1: was a period of time where it was really expanding
• 25:08
  Speaker 1: really fast, and now it's expanding but not as fast.
• 25:11
  Speaker 1: And so what do you call inflation? Is it that
• 25:14
  Speaker 1: rapid expansion or is it the whole thing, or is
• 25:16
  Speaker 1: it that's still kind of undecided. That's a little bit fuzzy. Yeah,
• 25:20
  Speaker 1: I think if you talk to most cosmologists, they would
• 25:23
  Speaker 1: think about inflation as this very narrow period from tend
• 25:27
  Speaker 1: to the minus thirty six seconds after somehow the universe
• 25:31
  Speaker 1: was created, to tend to the minus thirty two seconds
• 25:34
  Speaker 1: after the universe was created, in which you had this
• 25:37
  Speaker 1: enormous expansion in the universe. It seems like a factor
• 25:40
  Speaker 1: of ten to the twenty six. That's what they would
• 25:43
  Speaker 1: think of as inflation. But I'd also like to think
• 25:46
  Speaker 1: about what, you know, what expansion is still happening, and
• 25:48
  Speaker 1: so maybe this is still really part of inflation. But
• 25:50
  Speaker 1: that was the most dramatic moment, and so I think,
• 25:54
  Speaker 1: you know, if you talk about inflation, that's the moment
• 25:56
  Speaker 1: that people are thinking about. Oh, I see, like we're
• 25:58
  Speaker 1: maybe it's just at the air party of the inflation,
• 26:01
  Speaker 1: but you could technically maybe still call it inflation night,
• 26:05
  Speaker 1: you know, like the Oscar's Night. That's right, is the
• 26:07
  Speaker 1: celebration after the super Bowl part of the super Bowl. Yeah,
• 26:10
  Speaker 1: you know, but it's nothing like yeah, like the tailgating
• 26:14
  Speaker 1: counts as part of the event, surely, yeah, exactly. The
• 26:18
  Speaker 1: tailgating created the whole thing. It's only because the fans
• 26:21
  Speaker 1: and you can even have a super Bowl. So there
• 26:23
  Speaker 1: you go. And one of my favorite things about inflation
• 26:26
  Speaker 1: is just sort of the mind boggling numbers. We're talking
• 26:28
  Speaker 1: about a really brief amount of time. Tend to the
• 26:31
  Speaker 1: minus thirty two seconds. It's like impossible to think about.
• 26:35
  Speaker 1: We talked recently on a podcast about how long particles live,
• 26:39
  Speaker 1: and I said that they last like ten to the
• 26:41
  Speaker 1: minus twenty three seconds, which seems impossibly short, but you know,
• 26:45
  Speaker 1: compared to tend to the minus thirty six. That's a
• 26:48
  Speaker 1: huge amount of time. The ideas that the universe went
• 26:50
  Speaker 1: from almost or actually infinitely dense and infinitely dense infinity
• 26:58
  Speaker 1: to a less infinite lead dance infinity in a matter
• 27:02
  Speaker 1: of seconds or fractions of fractions of a second. And
• 27:06
  Speaker 1: the expansion also is incredible. I mean ten to the
• 27:10
  Speaker 1: twenty six expansion is hard to get your mind around. Yeah,
• 27:13
  Speaker 1: it would take one meter and expanded to ten billion
• 27:18
  Speaker 1: light years. That's what happened at the beginning of time.
• 27:21
  Speaker 1: Is that a meter, Like suddenly a meter became ten
• 27:24
  Speaker 1: billion light years. Yeah, so the stuff that's in a
• 27:27
  Speaker 1: meter of space got stretched out and spread out over
• 27:30
  Speaker 1: ten billion light years in a matter of ten to
• 27:33
  Speaker 1: minus thirty two seconds. Yeah, one pachinko second or whatever
• 27:36
  Speaker 1: that unit is second. You know, if you're a cosmology is,
• 27:41
  Speaker 1: you get to make up whatever terms like because you're
• 27:43
  Speaker 1: this is uncharted territory in terms of scientific prefixes. Right,
• 27:47
  Speaker 1: I think I think you should claim it right now,
• 27:49
  Speaker 1: go online to chink that's the sound of me claiming
• 27:52
  Speaker 1: pachinko second and then gaining royalties from it. Then you
• 27:56
  Speaker 1: get to change seconds and the other thing to wrap
• 27:59
  Speaker 1: your mind around is that this is stuff that's happening
• 28:01
  Speaker 1: faster than the speed of light. You know, light can't
• 28:04
  Speaker 1: travel ten billion light years in ten to the minus
• 28:07
  Speaker 1: thirty two seconds, obviously, right, it would take ten billion
• 28:10
  Speaker 1: light years years to cross that distance. That's right, even
• 28:14
  Speaker 1: Han Solo would take twelve par Sex to get that far.
• 28:18
  Speaker 1: Which hand Solo though? That do you want here? The
• 28:20
  Speaker 1: old of course, the old one, the original? And I
• 28:24
  Speaker 1: want to get a shout out to all those fans
• 28:26
  Speaker 1: out there who wrote in and gave me an explanation
• 28:29
  Speaker 1: for why Han Solo quoted his Kessel run time in
• 28:32
  Speaker 1: par Sex because he found a shortcut. He wasn't using
• 28:36
  Speaker 1: it as a measure of time. He was referring to
• 28:38
  Speaker 1: the fact that he took a trip near some gravitational well,
• 28:40
  Speaker 1: which basically shortened his trip through space. So thank you
• 28:43
  Speaker 1: to all those fans who educated me on the physics
• 28:45
  Speaker 1: of Star Wars. Sounds like a whole episode we should do,
• 28:48
  Speaker 1: We should, certainly. But the idea here is that space
• 28:52
  Speaker 1: expanded faster than the speed of light. And so for
• 28:55
  Speaker 1: those of you physics afficionados who are thinking, what nothing
• 28:57
  Speaker 1: can go fast in the speed of light, you're night
• 29:00
  Speaker 1: that nothing can go faster than the speed of light
• 29:02
  Speaker 1: through space. But there's no limit to how fast space
• 29:06
  Speaker 1: can expand really no limit. You think you think space
• 29:09
  Speaker 1: can expand infinitely. Well, it made a pretty impressive expansion
• 29:14
  Speaker 1: in the first few moments of the universe. I mean,
• 29:16
  Speaker 1: I'm impressed we are not aware of a limit. I
• 29:18
  Speaker 1: mean there could be a limit, but you know, we
• 29:20
  Speaker 1: have evidence that this expansion happened in a mind boggling speed.
• 29:25
  Speaker 1: So things that used to be close by, they used
• 29:27
  Speaker 1: to be like a meter apart, where all of a sudden,
• 29:30
  Speaker 1: cosmically separated. They were in their own essentially observable universes.
• 29:35
  Speaker 1: You know, they could no longer see each other or
• 29:37
  Speaker 1: communicate with each other. That's a little sad. You know,
• 29:42
  Speaker 1: something tore them apart. Yeah, something tore them apart. And
• 29:45
  Speaker 1: that's actually an important clue as to why we think
• 29:48
  Speaker 1: inflation happened. And you know, this kind of expansion is
• 29:52
  Speaker 1: the same kind of expansion that we're talking about now
• 29:55
  Speaker 1: that we're talking about for dark energy. You know, people
• 29:58
  Speaker 1: in the interviews who said, huh, in space expanding now
• 30:01
  Speaker 1: is cosmic inflation talking about the current expansion of the universe. Maybe, right,
• 30:06
  Speaker 1: that there's no difference in the kind of expansion we're
• 30:09
  Speaker 1: seeing now that's driven by dark energy and the kind
• 30:12
  Speaker 1: of expansion that we're talking about for cosmic inflation. They're
• 30:15
  Speaker 1: the same expansion of space, right, And so so this was,
• 30:20
  Speaker 1: um what we that short, super crazy period happened near
• 30:25
  Speaker 1: the beginning of time, and it happened really fast, but
• 30:29
  Speaker 1: we don't know kind of why it happened, right, We
• 30:32
  Speaker 1: don't know what happened, and we don't know why it
• 30:35
  Speaker 1: stopped happening and sort of cool off for a while,
• 30:38
  Speaker 1: and then we don't know why it started happening a
• 30:40
  Speaker 1: little bit again five billion years ago when dark energy
• 30:44
  Speaker 1: sort of started taking over the universe. So yeah, we
• 30:47
  Speaker 1: don't understand the mechanism of it at all, right, but
• 30:50
  Speaker 1: it is pretty crazy, and maybe that is that kind
• 30:52
  Speaker 1: of where the idea of a big band came from,
• 30:55
  Speaker 1: Like from this crazy expansion. It's almost like an explosion
• 30:58
  Speaker 1: of space, right, you might call it or a bang
• 31:01
  Speaker 1: of space, or I think the original name big Bang
• 31:04
  Speaker 1: came as a sort of a joke trying to mock
• 31:06
  Speaker 1: somebody else's scientific theory, and that was thinking of the
• 31:09
  Speaker 1: universe is starting from a point and an explosion through space.
• 31:13
  Speaker 1: And people were like, what are you suggesting as a
• 31:15
  Speaker 1: theory of the whole universe? Something as whimsical as that
• 31:18
  Speaker 1: Big Bang? You know, I think probably said with a
• 31:21
  Speaker 1: snotty British accident, you know exactly what the sneer, right,
• 31:26
  Speaker 1: the curled lip, but it caught on it like the
• 31:29
  Speaker 1: Big mag like the Big mag. It was catchy precisely,
• 31:34
  Speaker 1: and you know it has its own special sauce. And
• 31:38
  Speaker 1: but it is sort of it is sort incredible that
• 31:41
  Speaker 1: I mean, it's sort of like if you were alive
• 31:43
  Speaker 1: back then, it would you would not survive that, right,
• 31:45
  Speaker 1: It would feel like an explosion. It would feel like
• 31:47
  Speaker 1: this crazy violent, uh you know, sudden thing that it
• 31:52
  Speaker 1: just happened suddenly. Yeah, if you're two ms high, then
• 31:55
  Speaker 1: you would suddenly become a twenty billion light year long
• 32:00
  Speaker 1: staying on the universe. Right, I feel like I'm a
• 32:03
  Speaker 1: staying in the universe now that yeah, but you're localized,
• 32:06
  Speaker 1: like infinitely stayed. Do you want to be a cosmic
• 32:10
  Speaker 1: smear in the universe? You know? And if you are
• 32:13
  Speaker 1: reading that time travel device, be careful don't go back
• 32:16
  Speaker 1: to far because you do not want to experience cosmic inflation, right,
• 32:21
  Speaker 1: but you know it's it's space and time are tied together.
• 32:23
  Speaker 1: So is this was time also moving slower or was
• 32:27
  Speaker 1: time moving? Is this all measured at the same time scale?
• 32:31
  Speaker 1: Oh yeah, that's a great question and a deep one,
• 32:33
  Speaker 1: and we don't really understand. But we're measuring these things
• 32:36
  Speaker 1: according to our time, so our proper time. You know
• 32:40
  Speaker 1: what when you have experienced in terms of time, if
• 32:42
  Speaker 1: you're living through that period, I don't know. And we
• 32:46
  Speaker 1: don't really have a mechanism for explaining how this happened.
• 32:49
  Speaker 1: We just sort of sort of describing that it did.
• 32:51
  Speaker 1: And so we don't understand, like, is this part of
• 32:54
  Speaker 1: general relativity, there's some term you can add to the
• 32:56
  Speaker 1: equations of general realtivity that create this expansion, or is
• 32:59
  Speaker 1: it some totally different than it is stretching space? And
• 33:02
  Speaker 1: so the answer to how it affects time depends a
• 33:05
  Speaker 1: little bit on the details of what's doing it, whether
• 33:08
  Speaker 1: it's part of general relativity or not. I think time
• 33:12
  Speaker 1: itself cost inflation about that? Is that a new idea?
• 33:17
  Speaker 1: Lame Craig lame credit to that high fi novel. That's right,
• 33:21
  Speaker 1: that is officially your idea. And look forward to seeing
• 33:24
  Speaker 1: the paper you're writing on it. All right, let's get
• 33:28
  Speaker 1: into why we think costmic inflation even happened in the
• 33:31
  Speaker 1: first place, and let's get into what is still a
• 33:34
  Speaker 1: big mystery about it. But first let's take another break. Okay,
• 33:50
  Speaker 1: Daniel Lid we're talking about cosmic inflation, which is the
• 33:54
  Speaker 1: new Big Bang? Should we just call it the big
• 33:56
  Speaker 1: inflationary Bang, the Biggest Bang? Maybe the bangie inflation. But
• 34:03
  Speaker 1: so that's a crazy idea, that this idea that the
• 34:05
  Speaker 1: universe went from an infinitely dense infinity to a less
• 34:11
  Speaker 1: infinitely dense infinity in less than ten to the twenty
• 34:15
  Speaker 1: six seconds. That's crazy. It's crazy. But you know, the
• 34:18
  Speaker 1: universe and reality are no stranger to absurdity, right, They
• 34:23
  Speaker 1: don't care what your definition of crazy is. Yeah, and
• 34:26
  Speaker 1: crazy stuff has happened. And that's one of my favorite
• 34:29
  Speaker 1: things about physics is learning that the universe is bonkers,
• 34:32
  Speaker 1: bonkers beyond our imagination sometimes so it stretches our concept
• 34:37
  Speaker 1: of reality completely. I guess my question to you is
• 34:40
  Speaker 1: why do scientists think that so much happen is such
• 34:43
  Speaker 1: a short amount of time? You know, basically, why do
• 34:46
  Speaker 1: we think that the Big Bang or the inflation happened
• 34:49
  Speaker 1: in the first place. Yeah, well, it solves some problems.
• 34:52
  Speaker 1: It explains some of the things that we see that
• 34:54
  Speaker 1: we can't otherwise resolve. I mean, you might come up
• 34:56
  Speaker 1: with another theory that explains what we see out there,
• 35:00
  Speaker 1: but it has to explain all the stuff that we
• 35:01
  Speaker 1: see and tie up all the loose ends. And one
• 35:04
  Speaker 1: of the things is what we mentioned earlier on is
• 35:06
  Speaker 1: that we seem to be at the center of the
• 35:08
  Speaker 1: universe and that doesn't make sense. And the the hot Big
• 35:11
  Speaker 1: Bang model we have a point that explodes out, but
• 35:14
  Speaker 1: it does explain what we see if the whole universe
• 35:17
  Speaker 1: was infinite and expanded out everywhere at once, because then
• 35:21
  Speaker 1: everywhere looks like it's at the center of the universe.
• 35:24
  Speaker 1: It's like you're in the middle of a loaf of
• 35:26
  Speaker 1: bread and all the reasons as it's baking, all the
• 35:29
  Speaker 1: reasons are moving away from you. That's true, no matter
• 35:31
  Speaker 1: where you are in this infinite loaf of bread. Yeah,
• 35:34
  Speaker 1: it's like being in a rubber sheet. Right when you
• 35:37
  Speaker 1: stretch it out wherever you stand, it looks like everything's
• 35:40
  Speaker 1: blooming away from you. Yeah, exactly, And and that's pretty compelling.
• 35:44
  Speaker 1: But then you might ask, all right, well, that just
• 35:46
  Speaker 1: requires that the universe is infinite and it is filled
• 35:49
  Speaker 1: with an infor amount of stuff. Why do you think
• 35:51
  Speaker 1: it had this crazy expansion? And part of that comes
• 35:54
  Speaker 1: with what we see out there in the universe is
• 35:56
  Speaker 1: that the universe is pretty smooth. I mean, there are
• 36:00
  Speaker 1: clumps and galaxies and solar systems. Will get into that
• 36:02
  Speaker 1: in a moment, but if you average out over it,
• 36:05
  Speaker 1: it looks pretty smooth. And most specifically, if you look
• 36:09
  Speaker 1: at this cosmic microwave background radiation, this light we've talked
• 36:13
  Speaker 1: about that comes from like three hundred thousand years after
• 36:16
  Speaker 1: the Big Bang, when the universe was a hot plasma.
• 36:19
  Speaker 1: We see that light and we use that light to
• 36:22
  Speaker 1: measure it's sort of the temperature of the universe by
• 36:24
  Speaker 1: the frequency of the light. And it's really really, really smooth.
• 36:30
  Speaker 1: Like it looks like the universe was basically the same
• 36:32
  Speaker 1: temperature everywhere. And that's weird. It's it's very even, right,
• 36:37
  Speaker 1: It's like it it all, it all looks the same
• 36:39
  Speaker 1: almost from every direction. Yeah, it looks like a smooth bath,
• 36:43
  Speaker 1: you know. It looks like the temperature varies by one
• 36:46
  Speaker 1: part in a hundred thousand or one part in ten
• 36:49
  Speaker 1: thousand from here to there to the other place. And
• 36:51
  Speaker 1: you might be thinking, well, what what's weird about that? Right, Well,
• 36:55
  Speaker 1: it's weird from the point of view that those things
• 36:58
  Speaker 1: are cosmically far upon heart. If you look at light
• 37:02
  Speaker 1: that's coming to us from one direction in the cosmic
• 37:04
  Speaker 1: micro background radiation, it's been traveling the whole history of
• 37:08
  Speaker 1: the universe, just got here. If you look from the
• 37:10
  Speaker 1: other direction, life coming from the other direction has also
• 37:14
  Speaker 1: been traveling the whole history universe and just got here.
• 37:17
  Speaker 1: So it's the first time they ever met, right from
• 37:19
  Speaker 1: different ends of the universe. Right, one of them came
• 37:22
  Speaker 1: from the left edge of the universe and the other
• 37:24
  Speaker 1: one came from the right edge of the right. Yeah, well,
• 37:27
  Speaker 1: even if there aren't any edges, they came from totally
• 37:29
  Speaker 1: separated spots, spots that have not had time to talk
• 37:32
  Speaker 1: to each other or communicate in any way since the
• 37:35
  Speaker 1: beginning of the universe. Right, that's weird. That's weird because
• 37:40
  Speaker 1: they're the same temperature, and the only way you can
• 37:42
  Speaker 1: get stuff to be the same temperature is to let
• 37:45
  Speaker 1: it mix, Right, Like if you put an ice cube
• 37:48
  Speaker 1: into hot water, then you have a cold spot in
• 37:52
  Speaker 1: your water, and you have to wait for things to mix,
• 37:55
  Speaker 1: for the temperature to get so even. And so it
• 37:57
  Speaker 1: looks like the universe had a chance to mix. It
• 38:00
  Speaker 1: looks like the temperature smoothed out. But how did that happen?
• 38:05
  Speaker 1: Because these things have never had a chance to talk
• 38:07
  Speaker 1: to each other before. Why what? What if it touch
• 38:09
  Speaker 1: is how the universe was before? Yeah, it could be.
• 38:13
  Speaker 1: You know, a lot of these problems are sort of aesthetic.
• 38:17
  Speaker 1: You're like, well, I don't really get it. I don't
• 38:19
  Speaker 1: like that assumption. And so you could say, well, the
• 38:21
  Speaker 1: universe were just created like perfectly smooth. Yeah, just came
• 38:25
  Speaker 1: off the factory floor, nice and nice and toasty. Yeah,
• 38:29
  Speaker 1: nice and toasty. It's not exactly smooth. We see little
• 38:33
  Speaker 1: clumps in there, and the distribution of those clumps is
• 38:37
  Speaker 1: another thing that's explained by inflation. But you're right, this,
• 38:41
  Speaker 1: you know, by itself, this smoothness problem is not completely bulletproof. Right.
• 38:45
  Speaker 1: You could say, maybe the universe was just created almost
• 38:49
  Speaker 1: perfectly smooth, like maybe when photons are creative at the beginning,
• 38:53
  Speaker 1: they all have the same temperature. There would be another
• 38:55
  Speaker 1: way to explain it. There would be another way to
• 38:57
  Speaker 1: explain it. But the explanation that comes from inflation and
• 39:00
  Speaker 1: is that these things did once have a chance to mix.
• 39:04
  Speaker 1: That you know, before inflation, these photons, which were ten
• 39:07
  Speaker 1: billion light years apart, were only a meter apart. And
• 39:10
  Speaker 1: so there's a lot of time in this early plasma
• 39:13
  Speaker 1: for stuff to slash around and for things to get
• 39:15
  Speaker 1: smoothed out and for the universe to get to an
• 39:18
  Speaker 1: even temperature before things got inflated. Right, And so I
• 39:23
  Speaker 1: think I remember this that the the the way that
• 39:26
  Speaker 1: this explains it. It is that you need this kind
• 39:28
  Speaker 1: of rapid and violent expansion of space to basically take
• 39:33
  Speaker 1: the left edge photon and the right edge photon far
• 39:38
  Speaker 1: enough apart where it makes sense now. Yeah, so these
• 39:42
  Speaker 1: two have had to been inside the same sort of
• 39:45
  Speaker 1: cosmic horizon before, and now they're outside the cosmic horizon.
• 39:50
  Speaker 1: Cosmic horizon is something that is so far away that
• 39:54
  Speaker 1: you have not seen it because light from it has
• 39:56
  Speaker 1: never reached you in the history of the universe. Right,
• 39:59
  Speaker 1: there's a no way they could have talked before, And
• 40:02
  Speaker 1: yet it seems like they had have talked before. And
• 40:05
  Speaker 1: the expansion of space faster than the speed of light
• 40:08
  Speaker 1: is the thing that can do that. It can take
• 40:09
  Speaker 1: things that were inside the same cosmic horizon, right, that
• 40:13
  Speaker 1: are close enough to interact and talk to each other,
• 40:15
  Speaker 1: and smooth them become the same temperature, and push them
• 40:18
  Speaker 1: apart into their own separate cosmic horizons so that they
• 40:21
  Speaker 1: can no longer interact. And so that's what we think
• 40:24
  Speaker 1: we see now is that light from this from two
• 40:27
  Speaker 1: directions in the universe is now the same temperature, even
• 40:30
  Speaker 1: though without cosmic inflation, we don't think that they could
• 40:33
  Speaker 1: ever have met, right, It's like it's like a crazy
• 40:36
  Speaker 1: thing you've see in the universe that can only be
• 40:38
  Speaker 1: explained apparently by this crazy idea of inflation. Yeah, precisely.
• 40:43
  Speaker 1: That's one reason why we like inflation. It explains that.
• 40:48
  Speaker 1: And more specifically, the universe is not all the same temperature.
• 40:52
  Speaker 1: If you look at the cosmic microwave background radiation, this
• 40:55
  Speaker 1: light from the early universe, we said, it's like the
• 40:58
  Speaker 1: same too, within one in ten thousand, one in a
• 41:00
  Speaker 1: hundred thousand. Those wiggles are actually important. Those those deviations
• 41:04
  Speaker 1: from being exactly the same temperature are really important, and
• 41:08
  Speaker 1: we study those really carefully because those are the seeds
• 41:11
  Speaker 1: of the rest of the universe, right, that they're the
• 41:14
  Speaker 1: wrinkles that came from basically this giant stretching of the universe. Yeah,
• 41:18
  Speaker 1: those those wrinkles came from the giant stretching. And you
• 41:22
  Speaker 1: might wonder, like, all right, say the universe was created
• 41:25
  Speaker 1: perfectly smoothly, like you were saying earlier, Right, why couldn't
• 41:28
  Speaker 1: just come off the factory floor, like totally homogeneous. Well,
• 41:31
  Speaker 1: if you have a universe like that, then you never
• 41:34
  Speaker 1: get any sort of clumping. You don't get anything like
• 41:37
  Speaker 1: solar systems and hamsters and galaxies and stuff, because everything
• 41:41
  Speaker 1: is perfectly smooth and there's no place where things start
• 41:44
  Speaker 1: to clump together. To get any sort of clumping or structure,
• 41:47
  Speaker 1: you need something and that's not homogeneous, right, And so
• 41:50
  Speaker 1: you're saying, inflation is our only explanation for why the
• 41:54
  Speaker 1: universe is smooth and clumpy just the right amount that
• 41:59
  Speaker 1: we see it right now. That's right, because in physics
• 42:02
  Speaker 1: we have only one way to introduce random clumpiness, and
• 42:06
  Speaker 1: that's quantum mechanics. So the idea is the universe was
• 42:09
  Speaker 1: really really dense and perfectly smooth, and then quantum fluctuations
• 42:14
  Speaker 1: just like created a few particles here and a few
• 42:16
  Speaker 1: particles there. Now, normally, when that happens, and it's happening
• 42:19
  Speaker 1: all the time, it's not a big deal because there
• 42:21
  Speaker 1: are the quantum level so you don't see them. But
• 42:24
  Speaker 1: what if just when you're making those fluctuations, the universe
• 42:27
  Speaker 1: decides I'm gonna blow this up to ten billion light years?
• 42:31
  Speaker 1: Then all of a sudden, tiny little quantum fluctuations become
• 42:34
  Speaker 1: really big cosmic fluctuations, right, they become spread out over
• 42:39
  Speaker 1: the whole cosmos. Then they're big enough to seed gravity,
• 42:43
  Speaker 1: to get things moving, to clump stuff together. Right and
• 42:46
  Speaker 1: if so, so, if an inflation was not as dramatic,
• 42:51
  Speaker 1: then we wouldn't see those quantum fluctuations, right, because let's
• 42:55
  Speaker 1: say that inflation had actually taken longer than you wouldn't
• 43:00
  Speaker 1: you know, it wouldn't stretch those quantum fluctuations because things
• 43:03
  Speaker 1: would even out before you stretch out to the to
• 43:07
  Speaker 1: what we see now. Yeah, And that's why you need
• 43:09
  Speaker 1: to have inflation happened at the scale that had happened
• 43:11
  Speaker 1: like so dramatically and so quickly. You've got to catch
• 43:15
  Speaker 1: those quantum fluctuations with their pants down. Otherwise it doesn't
• 43:20
  Speaker 1: explain the universe were in. That's right, Their cosmic embarrassment
• 43:23
  Speaker 1: is the reason why we are here. Yeah, that's sort
• 43:27
  Speaker 1: of basically right, right, Like, it's like you needed to
• 43:30
  Speaker 1: catch the universe just the right time with this crazy
• 43:33
  Speaker 1: expansion like this photograph in order to explain what we
• 43:37
  Speaker 1: see now. Yeah, And we talked on the podcast recently
• 43:39
  Speaker 1: about another possibility, another different idea, which was cosmic strings.
• 43:43
  Speaker 1: People thought, maybe cosmic strings are the reason why we
• 43:45
  Speaker 1: see this sort of distribution of stuff in the universe,
• 43:48
  Speaker 1: but people look at them more carefully and it doesn't work.
• 43:50
  Speaker 1: You don't get this sort of the right kind of wiggles,
• 43:53
  Speaker 1: you don't get the right distribution of stuff here and
• 43:55
  Speaker 1: stuff there. But inflation gets it just right. Inflation says,
• 44:00
  Speaker 1: if you had that really dense plasma and then you
• 44:02
  Speaker 1: blew it up really quickly, you would expect to get
• 44:05
  Speaker 1: just the right density of stuff to form the kind
• 44:07
  Speaker 1: of structure that we see today, And there's no other
• 44:10
  Speaker 1: way to explain it in such fine detail that we know.
• 44:13
  Speaker 1: I mean, there are some other crazier ideas, but none
• 44:16
  Speaker 1: of them work as well as inflation, right, Yeah, Like,
• 44:18
  Speaker 1: if inflation at lasts it tended to the negative thirty
• 44:21
  Speaker 1: one seconds instead of tend to negative thirty two seconds,
• 44:24
  Speaker 1: then you and I wouldn't be here. Yeah, it would
• 44:27
  Speaker 1: be some other podcasts which would be not nearly as funny.
• 44:32
  Speaker 1: It would probably be over quicker. But there's a there's
• 44:34
  Speaker 1: some something else there. There's a real randomness right, Like
• 44:37
  Speaker 1: it tells you that the structure to universe, Like why
• 44:39
  Speaker 1: does a galaxy here comes from some like electron fluctuating
• 44:44
  Speaker 1: out of the vacuum fourteen billion years ago, And if
• 44:47
  Speaker 1: it had fluctuated in a different direction, we'd have a
• 44:49
  Speaker 1: different galaxy somewhere else. Like those tiny little quantum rolls
• 44:53
  Speaker 1: of the dye determine the specific structure of our universe today.
• 44:57
  Speaker 1: It mind boggling to think about. And they're super sensitive, right,
• 45:02
  Speaker 1: and totally random, super sensitive and totally random. Yeah. Wow.
• 45:06
  Speaker 1: So we we are lucky to have the universe we
• 45:09
  Speaker 1: have right now, and you listeners are lucky to have us, frankly,
• 45:12
  Speaker 1: and we are lucky to have you. We are very
• 45:15
  Speaker 1: glad that you fluctuated into existence. We are all lucky
• 45:18
  Speaker 1: to have each other. I think is the new theme
• 45:21
  Speaker 1: for Okay cool. I feel like I really understand there's
• 45:24
  Speaker 1: a little bit more, you know. It's it's like this
• 45:27
  Speaker 1: idea of an infinite infinity going less dense is and
• 45:32
  Speaker 1: very quickly in order to explain what we have now.
• 45:35
  Speaker 1: So does that mean, Daniel, that we know everything about
• 45:37
  Speaker 1: inflation and what happened at the beginning of time? Or
• 45:39
  Speaker 1: are there still things we don't know? There's not an
• 45:42
  Speaker 1: infinite amount of stuff that we don't know about inflation,
• 45:45
  Speaker 1: infinitely amount of stuff we don't know about an infinite
• 45:48
  Speaker 1: lead dance infinity that gets less infinite. Yeah, as our
• 45:52
  Speaker 1: knowledge grows, it feels like our ignorance is also growing,
• 45:54
  Speaker 1: or like our knowledge of our ignorance is inflating as well,
• 45:57
  Speaker 1: you know. But that's the fun part about science. I
• 46:00
  Speaker 1: think the biggest mystery about inflation is like what caused it?
• 46:04
  Speaker 1: What made it happen? What could possibly expand space at
• 46:07
  Speaker 1: this crazy rate? Right? Like why didn't the universe just
• 46:11
  Speaker 1: stay the way it was before? Why did it have
• 46:13
  Speaker 1: to have this crazy expansion? Yeah, and why did the
• 46:16
  Speaker 1: expansion stop? And so as usual, we don't have any idea,
• 46:19
  Speaker 1: but we've already given it a name, and of course yeah,
• 46:22
  Speaker 1: we've we've called it the infloton not a joke. I
• 46:28
  Speaker 1: know it sounds like I'm making that up. But created
• 46:31
  Speaker 1: this field called the infloton field, which would have an
• 46:33
  Speaker 1: infloton particle, and the ideas that this field causes this
• 46:37
  Speaker 1: crazy expansion. It sort of just puts off the question like,
• 46:40
  Speaker 1: all right, well, what creates the inflotton field and what
• 46:43
  Speaker 1: controls it? Well, we have no idea, but it's just
• 46:46
  Speaker 1: sort of like a place to put our ideas. Interesting,
• 46:49
  Speaker 1: So we owe our existence and our universe to the
• 46:52
  Speaker 1: infloton Yeah, and the infloton The idea there is like
• 46:55
  Speaker 1: the universe is filled with this infloton field, which expands
• 46:58
  Speaker 1: space and sort of decays into ordinary matter. And that's
• 47:04
  Speaker 1: how you get ordinary matter. You have in photon field,
• 47:06
  Speaker 1: which then turns into corks and electrons and other kinds
• 47:09
  Speaker 1: of fields. Um. And we don't know like what would
• 47:13
  Speaker 1: cause that decay, Like that's when inflation stops, is when
• 47:16
  Speaker 1: it turns into normal matter. But we don't know like
• 47:18
  Speaker 1: why would it stopped and or why was it there
• 47:21
  Speaker 1: in the first place? Yeah, what was there first place?
• 47:23
  Speaker 1: And also did it stop? Like there might be it
• 47:27
  Speaker 1: might be that inflation sort of stopped in our part
• 47:30
  Speaker 1: of the universe, but it's still going on in other
• 47:33
  Speaker 1: parts of the universe. Could be the rest of the universe.
• 47:35
  Speaker 1: We're like in a little bubble, a pocket universe, and
• 47:38
  Speaker 1: the rest of the universe is still inflating. And imagine
• 47:41
  Speaker 1: how far If it got that far in ten of
• 47:43
  Speaker 1: the minus thirty two seconds, imagine what it could do
• 47:45
  Speaker 1: in fourteen billion years. Wow. So you're saying that maybe
• 47:50
  Speaker 1: we are even more insignificant than we had previously imagined. Yeah,
• 47:55
  Speaker 1: that's this idea. It's called eternal inflation. That the universe
• 47:57
  Speaker 1: is continuously inflating, and occasionally the inflation sort of decays
• 48:02
  Speaker 1: into normal matter, and then you get the kind of
• 48:04
  Speaker 1: universe we're familiar with, but that most of the universe
• 48:07
  Speaker 1: is just this massively expanding infloton field. Wait, are you saying, Daniel,
• 48:11
  Speaker 1: that the infloton works in mysterious ways? I'm saying exactly that,
• 48:16
  Speaker 1: mostly because we don't understand it at all, And so
• 48:19
  Speaker 1: can I start a new religion based on the infloton?
• 48:22
  Speaker 1: Are you the high priest of the inflation here? Yeah,
• 48:25
  Speaker 1: because I am both the high priest and the parishioner
• 48:28
  Speaker 1: of my church of the Inflaton. Yes, please donate to
• 48:31
  Speaker 1: the Church of the Inflaton. I think we just replaced
• 48:35
  Speaker 1: the spagetti master. Yeah, and so of course this feels
• 48:39
  Speaker 1: like a big place holder because it is we don't know,
• 48:41
  Speaker 1: and so it's just a way to say, if inflation happened,
• 48:45
  Speaker 1: what's a possible way it might have happened. And then
• 48:47
  Speaker 1: let's start to get to work on, you know, figuring
• 48:50
  Speaker 1: out how that theory has to look. Step one, give
• 48:52
  Speaker 1: it a science names and then figure it out. Step
• 48:56
  Speaker 1: to get ridiculed by Jorge. Step three, get to work alright. Cool,
• 49:02
  Speaker 1: It sounds like there's still lots of answers to be
• 49:05
  Speaker 1: found in this and these are important answers, right, I
• 49:08
  Speaker 1: mean they're they're about the beginning of the universe and
• 49:11
  Speaker 1: why are things the way they are? And are things
• 49:14
  Speaker 1: going to change in the future. And you know, I
• 49:16
  Speaker 1: think in ten years or in twenty years, people will
• 49:18
  Speaker 1: look back at these ideas and think, oh, my gosh,
• 49:20
  Speaker 1: how absurd. I can't believe they really believe that stuff.
• 49:24
  Speaker 1: Because we're going to learn things about inflation, and we're
• 49:26
  Speaker 1: going to learn things about the history of the universe
• 49:28
  Speaker 1: and its current expansion that are going to give us
• 49:30
  Speaker 1: better ideas, even crazier ideas that are going to be
• 49:33
  Speaker 1: even more correct. And so this is the perfect example
• 49:37
  Speaker 1: of how our knowledge of the universe is constantly expanding.
• 49:40
  Speaker 1: We look back and think, wow, how silly. Yeah, you
• 49:43
  Speaker 1: know they say twenties smart physicists are twenty thirties ignoratons.
• 49:48
  Speaker 1: That's right, Yeah, I have twenty twenty vision, which means
• 49:52
  Speaker 1: I look back at ten and think one a bunch
• 49:54
  Speaker 1: of ideas. Well, I can't wait to have visions. That's
• 50:00
  Speaker 1: what happens in our old age, right, we all get
• 50:02
  Speaker 1: reading to us is all right? Well, maybe we'll get
• 50:06
  Speaker 1: into these mysteries a little bit deeper in the future podcast,
• 50:09
  Speaker 1: but for now, thanks for joining us. We hope you
• 50:11
  Speaker 1: enjoyed that. We hope we inflated your mind and took
• 50:13
  Speaker 1: you on a tour of the early universe. Thank you
• 50:16
  Speaker 1: very much. Before you still have a question after listening
• 50:26
  Speaker 1: to all these explanations, please drop us a line. We'd
• 50:29
  Speaker 1: love to hear from you. You can find us on Facebook, Twitter,
• 50:32
  Speaker 1: and Instagram at Daniel and Jorge that's one word, or
• 50:36
  Speaker 1: email us at Feedback at Daniel and Jorge dot com.
• 50:40
  Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain
• 50:43
  Speaker 1: the Universe is a production of I heart Radio. For
• 50:46
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• 50:49
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• 50:52
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