Latest / Daniel and Kelly’s Extraordinary Universe / Special 200th episode!

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Special 200th episode! · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Yeah, orgey, do you know what today is? Is it
0:11
Speaker 1: a special day today? Oh my god, I can't believe
0:13
Speaker 1: your forgot? Is it your birthday? Try again? Is it
0:18
Speaker 1: the anniversary of the Higgs Boson closer? It's actually our anniversary.
0:24
Speaker 1: Today is our two hundredth episode of Daniel and Jorge
0:28
Speaker 1: Explain the Universe. Two hundred episodes. Oh my gosh, it's
0:32
Speaker 1: a lot of physics and a lot of banana jots.
0:35
Speaker 1: It's a whole universe of banana physics. Hi am orhand
0:54
Speaker 1: my cartoonists and the creator of PhD comment. Hi. I'm Daniel.
0:57
Speaker 1: I'm a particle physicist, and I know at least two
1:00
Speaker 1: hundred things about physics, and I know at least two
1:02
Speaker 1: hundred bad jokes about physics. I've made ten to the
1:06
Speaker 1: two hundred bad jokes about physics, but our editor has
1:09
Speaker 1: removed most. And Welcome to our podcast, Daniel and Jorge
1:13
Speaker 1: Explained the Universe, a production of I Heart Radio, a
1:16
Speaker 1: project we started to explain to you all the amazing
1:19
Speaker 1: and crazy things out there in the universe, all the
1:21
Speaker 1: things we do know, the facts we've learned about the universe,
1:25
Speaker 1: the secret truth that we've revealed, and also the incredible questions,
1:28
Speaker 1: the things that science still has to figure out, the
1:31
Speaker 1: questions that scientists are asking, and the questions that you
1:34
Speaker 1: are asking, the deep mysteries of the universe around us.
1:37
Speaker 1: Because it turns out that there are more than two
1:39
Speaker 1: hundred questions you can ask about the universe and more
1:42
Speaker 1: than two hundred amazing facts to learn and to discover
1:46
Speaker 1: about how this crazy cosmos works. At least that's what
1:49
Speaker 1: we've discovered in doing this podcast. We had no idea
1:52
Speaker 1: how long we could keep going on. Yeah, today is
1:55
Speaker 1: a very special episode. It's our two hundred episode. What
1:59
Speaker 1: does that make it anial? Is it like a birthday,
2:01
Speaker 1: a broadcast day at pot day? I don't know, but
2:05
Speaker 1: you know, if you look up anniversaries, like you know,
2:07
Speaker 1: the fifth anniversaries paper, and the tenth anniversary is silver
2:11
Speaker 1: or whatever, the fiftieth anniversary is diamond. There is no
2:14
Speaker 1: culturally acceptable gift for two hundredth anniversary because he's ever
2:19
Speaker 1: lasted that long. I think they give you a Nobel
2:21
Speaker 1: price if you somehow managed to celebrate two hundredth anniversary,
2:25
Speaker 1: Maybe you should be the fossil anniversary something, because you've
2:28
Speaker 1: become fossilized. But congratulations Daniel, two hundred episodes. Did you
2:31
Speaker 1: ever think we would get to two hundred episodes? No?
2:34
Speaker 1: I thought you get sick of talking to me about
2:35
Speaker 1: physics after about ten or twenty. No, congratulations to you. Also,
2:39
Speaker 1: it's been a really fun ride. And thank you to
2:41
Speaker 1: all of our listeners who have listened to us talking
2:44
Speaker 1: about science and joking about bananas and shared your goofy
2:48
Speaker 1: curiosity with us. That's really what's powered us forward. So
2:51
Speaker 1: thanks for listening, and thanks for all the feedback and support. Well,
2:54
Speaker 1: I have definitely not gotten tired of listening to amazing
2:57
Speaker 1: physics and to listen to you explain rated. Um, I
3:01
Speaker 1: feel like I could go another two hundred episodes. Let's
3:04
Speaker 1: do it. Well. In honor of our two hundredth episode,
3:07
Speaker 1: I put out a tweet asking folks what we should
3:09
Speaker 1: do to celebrate our two hundredth episode, and as usual,
3:13
Speaker 1: I put out some silly suggestions and we did a
3:16
Speaker 1: little Twitter poll. Yeah, and so Daniel asked what should
3:19
Speaker 1: we do for a two hundred episode? And the options
3:21
Speaker 1: were one, eat two hundred bananas, to answer two hundred questions,
3:26
Speaker 1: three to two hundred different accents, and number four just
3:32
Speaker 1: shut up. And explain. That's right, and clearly I was
3:35
Speaker 1: going to do the explaining, but I was hoping that
3:36
Speaker 1: you would do the bananas in the accents seems a
3:40
Speaker 1: little lopsided. Daniel, Well, you're the creative one, right. How
3:44
Speaker 1: can I eat bananas and accents at the same time?
3:46
Speaker 1: Those count as different accents, you know, like Scottish or
3:49
Speaker 1: Scottish with the banana in your mouth sound very different.
3:51
Speaker 1: It was a close pole. It was a close poll, yes,
3:54
Speaker 1: exactly what it was. It dramatic like as you saw
3:56
Speaker 1: the numbers come in. Um, well, bananas was racing to
3:59
Speaker 1: the lead in the beginning, but eventually people voted for
4:03
Speaker 1: Answer two hundred questions got about thirty five Eat two
4:08
Speaker 1: hundred bananas in second place, and you know in last
4:11
Speaker 1: place was due two hundred accidents, which I was sort
4:13
Speaker 1: of hoping for. I think we have to trust the
4:15
Speaker 1: wisdom of the crowd here and not offend two hundred
4:19
Speaker 1: countries we can. There aren't two hundred countries to offend,
4:23
Speaker 1: so that would be pretty impressive if we could offend
4:25
Speaker 1: non existing countries. Yeah. So the top option was Answer
4:29
Speaker 1: two hundred questions, which when Daniel told me, I said
4:32
Speaker 1: it was a little impractical for a fifty minute podcast,
4:34
Speaker 1: that's right. They have to be like true or false questions,
4:37
Speaker 1: or you know, yes or no, or something which wouldn't
4:38
Speaker 1: be too satisfied, right. I started to think, if we
4:41
Speaker 1: take five minutes to answer each question, that's a thousand
4:44
Speaker 1: minute episode. That's basically the next two hundred episodes. Basically,
4:49
Speaker 1: we'd be done. We could celebrate our four hundred anniversary
4:53
Speaker 1: next week. Then, well, this podcast is really accelerating the
4:56
Speaker 1: logarithmic scales. We'll be doing our four thousand one in
5:00
Speaker 1: a month, that's right. And I started looking through the
5:02
Speaker 1: list of questions we've answered over email, because I answered
5:05
Speaker 1: hundreds of questions a week from listeners, and there's a
5:08
Speaker 1: lot of common things in there. But then or I
5:10
Speaker 1: had a better idea something else we could do to
5:12
Speaker 1: celebrate our two hundredth episode. Yeah, so it's be on
5:15
Speaker 1: the podcast. We'll be asking two hundred questions, but not
5:24
Speaker 1: two hundred number of questions, but a couple of questions
5:27
Speaker 1: about the number two hundred. That's right, because while the
5:30
Speaker 1: number ten and the number one hundred, and therefore the
5:32
Speaker 1: number two hundred are really just artifacts of the number
5:35
Speaker 1: of fingers we have in the way the human mind works.
5:38
Speaker 1: It's also an interesting way to ask questions about the universe,
5:41
Speaker 1: to think about like how far away are things or
5:43
Speaker 1: what happened in certain moments of time in the universe.
5:46
Speaker 1: It gives you like a fixed window to examine the universe.
5:49
Speaker 1: We'll be asking coincidentally to two hundred questions here in
5:54
Speaker 1: the podcast, and the first question has to do with
5:57
Speaker 1: what happened at the beginning of the universe. So the
5:59
Speaker 1: question is what happened in the first two hundred micro
6:02
Speaker 1: seconds of the universe. And then later on we'll tackle
6:06
Speaker 1: the another question about with the number two hundred, which
6:09
Speaker 1: is what can we find within two hundred light years
6:13
Speaker 1: of Earth? So a little bit of time and a
6:15
Speaker 1: little bit of space, a little bit of space time, Daniel,
6:18
Speaker 1: that's right. What can you find within two hundred light
6:21
Speaker 1: years of Earth? Makes me think like, are you looking
6:23
Speaker 1: for your keys? Are they somewhere out there in space?
6:28
Speaker 1: I do lose my keys a lot, even even in
6:30
Speaker 1: a pandemic where you don't go anywhere. Somehow I managed
6:33
Speaker 1: to lose my keys like every day. Well, we'll see
6:35
Speaker 1: if we can find them, all right, we'll tackle this
6:37
Speaker 1: first question first, which is what happened in the first
6:40
Speaker 1: two hundred micro seconds of the universe. Now, two hundred microseconds,
6:45
Speaker 1: that's like, boy, that's like point to milliseconds. It's not
6:48
Speaker 1: a lot of time. But it turns out a whole
6:50
Speaker 1: lot of stuff happened in the first two hundred microseconds
6:53
Speaker 1: to the universe. Basically everything's been boring ever since. Well,
6:58
Speaker 1: two d micro seconds. That's that's shorter than a blink, right,
7:01
Speaker 1: Like a blink is maybe a couple of microseconds, a
7:04
Speaker 1: couple of milliseconds. It's a very small amount of time. Absolutely, Yeah,
7:08
Speaker 1: So a lot happened in those first microseconds. A lot happened.
7:12
Speaker 1: And one of the most interesting questions really is how
7:14
Speaker 1: you even define like moment zero. If you're gonna say,
7:18
Speaker 1: let's take a window of time from the very beginning
7:20
Speaker 1: of the universe to two d microseconds afterwards, it's interesting
7:24
Speaker 1: to think about, like how the universe expands and cools,
7:26
Speaker 1: and we'll get into all of that. But then you
7:28
Speaker 1: have to wonder, like where does T equal zero? How
7:31
Speaker 1: do you define that moment? Do we even know that
7:33
Speaker 1: there was a T equal zero? So already like anchoring
7:37
Speaker 1: the left side, the early side of that window is very,
7:40
Speaker 1: very difficult. It makes me think, like was there a
7:43
Speaker 1: T minus one or like a countdown to the universe.
7:46
Speaker 1: Nobody really knows, And the problem is that we don't
7:49
Speaker 1: think about the history of the universe in that sort
7:51
Speaker 1: of forward way because we don't really have anything to
7:54
Speaker 1: build on. We don't know what was in the beginning
7:57
Speaker 1: or when the beginning was. Usually we think about it
7:59
Speaker 1: sort of in the reverse. We look at the universe now,
8:03
Speaker 1: and we look backwards in time as we look further
8:05
Speaker 1: further out into space, right, because remember the further out
8:08
Speaker 1: in space, you look older the universe is. So we
8:11
Speaker 1: can see how the universe looked a hundred years ago,
8:14
Speaker 1: a thousand years ago, a million years ago, a billion
8:17
Speaker 1: years ago, etcetera. And we can project backwards in time.
8:20
Speaker 1: So we tend to think of the history of the
8:22
Speaker 1: universe sort of from now and running the clock backwards,
8:26
Speaker 1: and we can do it pretty well, you know, back
8:28
Speaker 1: about thirteen billion years or so, But then it gets
8:31
Speaker 1: pretty murky and we have trouble extrapolating back. We don't
8:35
Speaker 1: know if there was a T equal zero, if there
8:37
Speaker 1: was like a T equals question mark, or who knows
8:39
Speaker 1: what was happening at the very beginning. That's interesting. Now,
8:43
Speaker 1: why does the picture he get fuzzy beyond if you
8:47
Speaker 1: rewind back to more than a few hundred thousand years
8:50
Speaker 1: from what what might be the beginning of time? Like
8:53
Speaker 1: what what? What actually marks up? Well, the reason is
8:56
Speaker 1: that things change, Things get really hot and dense. Right,
8:59
Speaker 1: the overall history of the universe is cooling and expanding,
9:02
Speaker 1: and so if you run that backwards from now we
9:04
Speaker 1: have a cold, large universe. You run that backwards, things
9:08
Speaker 1: get hotter and denser. And of course you could just
9:11
Speaker 1: do that naively, like assume that the laws of physics
9:14
Speaker 1: we have learned today from our cold universe still work
9:17
Speaker 1: back then, and just run the clock backwards and you
9:20
Speaker 1: get infinite density and you call that T equal zero.
9:23
Speaker 1: You could do that, but we don't think that's right.
9:27
Speaker 1: We don't think the laws we have work anymore as
9:29
Speaker 1: things get that hot and dense, just like you know,
9:33
Speaker 1: the physics of gases is different from the physics of
9:35
Speaker 1: liquids and the physics of solids, and so things change
9:38
Speaker 1: as you get hotter and denser, and then it becomes
9:40
Speaker 1: difficult to extrapolate because we're reaching into regions that we
9:43
Speaker 1: can't see anymore and we have no experience of because
9:48
Speaker 1: there's a moment in the early universe when the universe cooled.
9:51
Speaker 1: It was a hot, dense, nastiness, will talk about it,
9:54
Speaker 1: and it cooled to a place where light could fly through.
9:57
Speaker 1: It became transparent, And that's the last moment in the
10:00
Speaker 1: early universe that we can actually see. Beyond that, we're
10:04
Speaker 1: just really sort of guessing and extrapolating and using models,
10:07
Speaker 1: but those models are very uncertain. We really don't know
10:10
Speaker 1: what we're talking about. So a lot of the details
10:13
Speaker 1: we'll talk through today in this episode are really speculative.
10:16
Speaker 1: They're like, maybe it was this, and maybe it was that,
10:19
Speaker 1: and under various assumptions which seemed reasonable but could be
10:23
Speaker 1: totally wrong. You know, maybe this happened, But it's really guesswork.
10:27
Speaker 1: Is it guesswork because we don't know, like our simulations
10:30
Speaker 1: don't aren't very definitive, or like the physics of the
10:34
Speaker 1: universe might actually change it in those kind of conditions.
10:37
Speaker 1: We don't know how the physics of the universe operates
10:39
Speaker 1: in those very hot and dense environments. You know, we've
10:42
Speaker 1: only experienced it when it's pretty cold and separated, and
10:47
Speaker 1: so we're extrapolating back. We think we have ideas or
10:49
Speaker 1: how it might work, and we can simulate various ones
10:52
Speaker 1: of them, but we can't necessarily like tell the difference
10:54
Speaker 1: between if it's like this or if it's like that,
10:57
Speaker 1: and so we just we're extrapolating into the unknown, and
11:00
Speaker 1: and that's always very dangerous and delicate. Now, even the
11:03
Speaker 1: concept of time equals zero is weird, right, because I've
11:06
Speaker 1: heard people say that, you know, like it's it's almost
11:09
Speaker 1: like asking what is more north than the north Pole?
11:13
Speaker 1: Because once you get to the north pole, there's no
11:15
Speaker 1: more north? And is it the same? Also that you know,
11:19
Speaker 1: maybe time started at T equal zero and there was
11:22
Speaker 1: no time before that. It sounds bonkers to say that, right,
11:25
Speaker 1: like there was no time before that, because it's before
11:29
Speaker 1: mean if there was no time, right, It's it's confusing.
11:33
Speaker 1: It's hard to really get these ideas into your head.
11:35
Speaker 1: But it's true that some theories of the universe say
11:39
Speaker 1: that space and time were created at some moment and
11:44
Speaker 1: things have expanded and cooled since then, and before that point,
11:48
Speaker 1: there was no time, There was no space, there was
11:51
Speaker 1: no before that point. That's really hard to grasp your
11:55
Speaker 1: mind around because your mind lives in that space in
11:57
Speaker 1: that time. It's all you've experienced, and so it's all
12:00
Speaker 1: you can really imagine how you organize your thinking. It's
12:03
Speaker 1: how we think about causality and logic, and a it happens,
12:06
Speaker 1: then be happens, then see happens. But it doesn't mean
12:09
Speaker 1: it's the only way the universe can be. And so
12:12
Speaker 1: it's extraordinarily difficult to sort of extrapolate your brain and
12:15
Speaker 1: you're thinking into something completely unfamiliar, right, And so what
12:19
Speaker 1: we do is we have these frameworks like general relativity
12:22
Speaker 1: and quantum mechanics that try to tell us about what
12:24
Speaker 1: might have happened, But those aren't very conclusive either. I
12:28
Speaker 1: guess the North Pole analogy kind of works also in that,
12:30
Speaker 1: you know, like here where we are. You know, if
12:33
Speaker 1: you have like a compass, it's pretty clear how to
12:36
Speaker 1: use it, Like, you know, it tells you north and
12:38
Speaker 1: right and south and east and west, and you can
12:40
Speaker 1: walk around pretty easy blue. But if you are like
12:42
Speaker 1: near the North Pole, it might be a little tricky
12:45
Speaker 1: to use a compass, right, Yeah, if you're at the
12:48
Speaker 1: North Pole, you'd be a little disoriented. Yeah, if you're
12:50
Speaker 1: at the north pole. There is no more north to go, right,
12:53
Speaker 1: you can't go any north eier than that. But we
12:55
Speaker 1: don't know if time works that way. It could be
12:58
Speaker 1: that there was stuff for you know, these early moments,
13:02
Speaker 1: these singularities. There was a whole other universe perhaps which
13:05
Speaker 1: came down into a big crunch or something else totally different,
13:09
Speaker 1: some sort of other weird kind of thing which gave
13:11
Speaker 1: birth two hours space and time. You know, our entire universe,
13:15
Speaker 1: Our space and time could be a bubble of that
13:18
Speaker 1: other pre universe stuff like decaying into a universe. There
13:22
Speaker 1: could be a whole spectrum of other universes also that
13:24
Speaker 1: were created in the same moment, or the could that
13:27
Speaker 1: are still being created now. There could be like you know,
13:29
Speaker 1: moments of creation happening right now, really far away in
13:32
Speaker 1: this other meta space. It sounds like bonker speculation because
13:36
Speaker 1: it is mostly because we're so clueless. You mean, like now,
13:39
Speaker 1: like as we speak, there could be some time equal
13:41
Speaker 1: zero moments right now for other universes in this universe. Yeah.
13:45
Speaker 1: One idea of how our universe got started is that
13:49
Speaker 1: there was some sort of like pre universe stuff some
13:53
Speaker 1: Inflaton fields, and that our universe is essentially some random
13:58
Speaker 1: spontaneous decay of at and that's when our universe began,
14:02
Speaker 1: and that influence on Field is just like expanding and
14:05
Speaker 1: creating and eternally inflating. But all the time it's parts
14:09
Speaker 1: of it are decaying and starting whole new universes, their
14:12
Speaker 1: universes that haven't even gotten started yet, in universes that
14:14
Speaker 1: are trillions of years old. And none of this is
14:16
Speaker 1: anything we know. It's just like it's a crazy idea,
14:20
Speaker 1: and in a thousand years people will read about these
14:22
Speaker 1: ideas the way we think about, you know, the Greek's
14:25
Speaker 1: ideas about air, water, fire, and earth. We're like, well,
14:28
Speaker 1: that's cute, you know, and it could have been true.
14:31
Speaker 1: I suppose, yeah, it's it's well meaning, carefully thought out,
14:36
Speaker 1: totally wrong, And that could be the way we describe
14:39
Speaker 1: all of our current ideas about what happened to T
14:41
Speaker 1: equal zero and whether T equal zero even makes sense.
14:44
Speaker 1: It could be like cute to future busicists, exactly lessly
14:48
Speaker 1: cute to a future five year olds. Man, five year olds,
14:50
Speaker 1: and a thousand years will laugh at our ideas that
14:54
Speaker 1: were like, oh, you're ridiculous, that's silly, oh man, well,
14:58
Speaker 1: five year olds already laugh at me, Daniel, so that
15:01
Speaker 1: that's going to be We'll pretend that's on purpose though,
15:03
Speaker 1: all right, so it seems like, okay, so we can't
15:05
Speaker 1: see that well beyond a few hundred thousand years into
15:10
Speaker 1: the universe. So really asking like what happened in the
15:12
Speaker 1: first twohundred microseconds is really speculative, then that's right. All
15:17
Speaker 1: you can do is say, like, you know, extrapolate backwards
15:20
Speaker 1: from where we are it gets hotter and denser, hotter
15:23
Speaker 1: and denser, and pretend that you know how to extrapolate
15:26
Speaker 1: back to some point like general relativity says you can
15:29
Speaker 1: extrapolate all the way back to a point of infinite
15:31
Speaker 1: density and temperature. But you know, we know that general
15:34
Speaker 1: relativity is probably wrong when it talks about singularities and
15:37
Speaker 1: stuff like that, because it ignores important things like quantum mechanics,
15:42
Speaker 1: which tells us that you can't have an infinite amount
15:45
Speaker 1: of stuff in a tiny zero volume point and know
15:47
Speaker 1: all about it. So definitely something wonky happens. But you know,
15:51
Speaker 1: you can extrapolate sort of naively and say we'll call
15:55
Speaker 1: this t equal zero and we'll move forward from there.
15:58
Speaker 1: I see, I see so we're gonna plant the flow.
16:00
Speaker 1: I can say this is tequals zero, and then we're
16:02
Speaker 1: going to see what can the universe do to get
16:04
Speaker 1: us to where we are today? Kind of yeah, exactly.
16:07
Speaker 1: All right, well let's get into that and to the
16:09
Speaker 1: question of what is within two hundred light years of Earth?
16:12
Speaker 1: But first let's take a quick break. All right, Daniel,
16:28
Speaker 1: we're celebrating our two birthday. Does that mean that I'm
16:31
Speaker 1: two years old and you're two hundred years old, or
16:34
Speaker 1: we're each a hundred years old? It means we should
16:36
Speaker 1: have retired a hundred and thirty years ago. I feel
16:40
Speaker 1: like this podcast has aged me two years. I feel
16:43
Speaker 1: like I'm two hundred light years from where I started. There,
16:45
Speaker 1: you go, all right, well, so we're talking about the
16:47
Speaker 1: first two hundred microseconds of the universe, and so we'll
16:51
Speaker 1: start with time equals zero. What what happened at times zero? Daniel?
16:54
Speaker 1: We don't know, but one idea is that there was
16:56
Speaker 1: a singularity that you know, the universe was super hot
16:59
Speaker 1: and super dense. And I think a lot of people
17:01
Speaker 1: imagine this as a single point. They hear singularity to
17:05
Speaker 1: think a single point. They think one hot, dense spot
17:09
Speaker 1: like the entire energy and all the matter of the
17:12
Speaker 1: universe was in a really tiny dot. But it's better
17:17
Speaker 1: not to think about it as one place, but more
17:19
Speaker 1: to think about it as the density. Because we don't
17:22
Speaker 1: know if the universe is finite or infinite. Possible that
17:26
Speaker 1: when the universe started it was already infinite, and that
17:30
Speaker 1: this singularity we're talking about was everywhere like multiple singularity, yes, yes, precisely,
17:36
Speaker 1: like a non singular singularity. Yes. Like the singularity refers
17:40
Speaker 1: not to how many of them there were, but the
17:42
Speaker 1: fact that the density becomes infinite singularity refers to what
17:46
Speaker 1: happens to the equations, that the equations get infinities in them,
17:50
Speaker 1: because the density becomes infinite, not the size of it.
17:53
Speaker 1: And there's a i think a very common misconception that
17:56
Speaker 1: the Big Bang or pre Big Bang starts with a dot,
17:59
Speaker 1: and a dots small than an adam becomes the entire universe.
18:02
Speaker 1: And because we don't know how big the universe is,
18:04
Speaker 1: it could have been a little blob, it could have
18:06
Speaker 1: been an infinite extent. It's better to think about it
18:08
Speaker 1: in terms of infinite density, or like an infinite number
18:12
Speaker 1: of dots, an infinite number of dots. Yeah, The thing
18:15
Speaker 1: we do know is that the universe was denser and
18:18
Speaker 1: harder back then. We don't know how much of it
18:20
Speaker 1: there was, could have been infinite, could be finite, and
18:23
Speaker 1: loop all around on itself. That's a whole other episode
18:26
Speaker 1: about the size and shape of the universe, which is fascinating.
18:28
Speaker 1: But to think through the history of the universe is
18:30
Speaker 1: mostly to think about the density changing da days that
18:34
Speaker 1: you know, there's no real reason for this to exist,
18:37
Speaker 1: just somehow the universe what we know was really dance,
18:41
Speaker 1: almost like infinitely dance. Yeah, there must have been a
18:43
Speaker 1: reason for it to exist, because it does. And we
18:45
Speaker 1: think the universe follows reasons and laws. We just don't
18:48
Speaker 1: know what they are and we can't argue for it.
18:50
Speaker 1: We don't know why there was something instead of nothing,
18:53
Speaker 1: and why there was this, and could there have been
18:55
Speaker 1: other things, and you know, just really shockingly basic questions
18:58
Speaker 1: that we have really no clue about. Okay, so we
19:00
Speaker 1: had to super dance state almost infinitely dense, maybe everywhere,
19:04
Speaker 1: maybe just one dot, and then what's next thing that
19:07
Speaker 1: happened and what happened in the first tend to the
19:09
Speaker 1: minus you know, forty three seconds, so The picture you
19:11
Speaker 1: should have in your mind is that we have space,
19:14
Speaker 1: and space is really really hot, like there's a huge
19:17
Speaker 1: amount of energy. Right. The density we're really talking about
19:20
Speaker 1: there is energy density. And if you've been following the podcast,
19:24
Speaker 1: you know that we like to think about space in
19:25
Speaker 1: terms of quantum fields. Every point in space has fields
19:29
Speaker 1: in it, the electron fields of cork fields, the photon fields, etcetera.
19:33
Speaker 1: And particles that we think about today are little blobs
19:36
Speaker 1: of excitations of those fields. Today, most of those fields
19:40
Speaker 1: are very very low energy. Most of space is empty
19:42
Speaker 1: in those fields are zero. But back then, infinite density
19:46
Speaker 1: really means all those fields are going nuts. They're going crazy,
19:49
Speaker 1: they're oscillating, they're just full of energy. And so instead
19:53
Speaker 1: of thinking about individual particles, it's like having an ocean, right,
19:56
Speaker 1: you don't think about a drop of water. When you
19:59
Speaker 1: have an ocean. You can just think about the entire crazy,
20:01
Speaker 1: turbulent blob and it's doing all sorts of stuff. So
20:04
Speaker 1: the first ten to the minus forty three seconds of
20:07
Speaker 1: the universe we called this the plant epoch. Everything was
20:10
Speaker 1: hot and dense in these fields were just going crazy.
20:13
Speaker 1: Now I have a question, though, somebody's talk about that.
20:16
Speaker 1: It's not just like stuff that was crammed in together
20:19
Speaker 1: really tightly. It's also that space itself was smaller, much smaller.
20:26
Speaker 1: So it's like it's both those things. It's like everything
20:28
Speaker 1: was crowned in together and also space was smaller. That's right.
20:32
Speaker 1: There's two kinds of expansion we're gonna talk about later.
20:34
Speaker 1: One is the expansion of stuff through space as things
20:38
Speaker 1: spread out into existing space. The other is the expansion
20:41
Speaker 1: of space that you create more space, and new space
20:45
Speaker 1: itself is created. Because remember that space is not just
20:48
Speaker 1: like a backdrop on which things happen. There's a dynamical
20:52
Speaker 1: connection between space and energy. Space curves and bends and
20:56
Speaker 1: expands in response to the mass and energy that's in it,
21:00
Speaker 1: and then it shapes the motion of that mass and energy.
21:03
Speaker 1: So space and mass and energy are two things that
21:06
Speaker 1: are very tightly coupled and respond to each other. Okay,
21:10
Speaker 1: so in the first you know point zero zero zero
21:13
Speaker 1: zero down to forty zeros one seconds, you said, that's
21:17
Speaker 1: called the planet. Yeah, and back there we had a
21:20
Speaker 1: bunch of really hot fields. And the thing to think
21:22
Speaker 1: about here is that there are no particles. What it's
21:25
Speaker 1: it's like too hot for particles like particles just kind
21:28
Speaker 1: of everything is just crazy. That's right. There are no
21:30
Speaker 1: isolated particles because everything is just too hot and too intense.
21:34
Speaker 1: It's all just energy in these fields. It's slashing around.
21:37
Speaker 1: You know, later on things will cool down enough for
21:39
Speaker 1: particles to form. But particles are like you know, when
21:42
Speaker 1: you have a few little isolated blobs of energy in
21:45
Speaker 1: the field. Here we have like an incredible turbulent ocean.
21:48
Speaker 1: So it makes no sense to think about in terms
21:50
Speaker 1: of particles. I mean, technically you could, you could say
21:53
Speaker 1: this field is ten ca jillion particles in it, but
21:56
Speaker 1: it doesn't really make any sense. It's really just energies,
21:58
Speaker 1: not discrete packets being around through space. It's just a
22:01
Speaker 1: huge blob of energy slashing around in the field. I see.
22:04
Speaker 1: There's no moment where you're like, oh, there's an electron.
22:06
Speaker 1: It's just that the whole field is just sit on fire. Yeah, precisely.
22:10
Speaker 1: You can't follow a drop of water in the ocean, right.
22:13
Speaker 1: And the other thing to think about is that the
22:15
Speaker 1: fields here behave differently, just like the way materials on
22:18
Speaker 1: Earth have phases as you cool them or or heat
22:22
Speaker 1: them up. The physics of them changes completely, right, The
22:25
Speaker 1: same thing happens for fields. They tend to act in
22:27
Speaker 1: different ways at different temperatures and different energy densities. And
22:32
Speaker 1: this is not like the laws of physics changing. It's
22:34
Speaker 1: just like how you can think about it, how you
22:36
Speaker 1: can describe it. The effective the emergent results of it
22:40
Speaker 1: are very different at different temperatures, just the same way
22:43
Speaker 1: they are for solid But can we still use the
22:45
Speaker 1: same equations we have, Like do our equations still work?
22:48
Speaker 1: We don't think they do. We think the equations that
22:50
Speaker 1: we have now only describe physics sort of at lower temperatures,
22:54
Speaker 1: that they're sort of like the falling at the effective
22:57
Speaker 1: equations for what happens when things are old. We don't
23:00
Speaker 1: think we have like the fundamental equations. Our equations should
23:04
Speaker 1: be like the low temperature limit of the true equations,
23:07
Speaker 1: which we haven't found yet. But for example, and we
23:10
Speaker 1: think that a very hot temperature is the early moments,
23:13
Speaker 1: all of the forces acted like one gravity, electromagnetism, the
23:18
Speaker 1: weak force, and the strong force. We think they're probably
23:20
Speaker 1: all just one force that acted together. What do you
23:23
Speaker 1: mean of force? Don't forces depend on particles to no?
23:26
Speaker 1: Forces are also just fields? Right, But we think that
23:29
Speaker 1: there was a single field that represents all those forces
23:33
Speaker 1: but combined into one. And we think when it was
23:35
Speaker 1: really hot and dense, that they acted together. They all
23:38
Speaker 1: had the same strength, and there were all just different
23:40
Speaker 1: components of one mega force which exists in the universe. Well,
23:44
Speaker 1: I think you just coined the term right there at
23:46
Speaker 1: the megaphorce. This is like to call it the grand
23:50
Speaker 1: unified theory. I like megaphorce better megaforce. It is, then,
23:56
Speaker 1: all right, so those are the first ten to the
23:58
Speaker 1: minus forty three second. Is then what happened? And things
24:01
Speaker 1: start to cool, things start to expand a little bit,
24:04
Speaker 1: and the first breaking happens. Here the force splits into two.
24:08
Speaker 1: You have gravity on one side, and then all the
24:11
Speaker 1: other forces electromagnetism, the weak force, and the strong force
24:15
Speaker 1: combined still into one single force, which we call electro strong.
24:19
Speaker 1: And so here the temperature has dropped enough that the
24:22
Speaker 1: force has split. It's like cracked. You know how. Sometimes
24:25
Speaker 1: when you cool something, you can freeze, or it can crack,
24:28
Speaker 1: or it can end them as some weird configuration. As
24:31
Speaker 1: the universe cooled, gravity sort of like froze and split
24:33
Speaker 1: off from the other forces. Interesting like inevitably or is
24:37
Speaker 1: it like a random you know, like an ice when
24:39
Speaker 1: you freeze eyes, you you sometimes get crystals here or
24:42
Speaker 1: crystals there. Is it random like that or is it
24:44
Speaker 1: like inevitable? Do you think that the equations were like
24:47
Speaker 1: we were always going to get gravity and these other
24:49
Speaker 1: forces we don't know. We call it spontaneous symmetry breaking
24:52
Speaker 1: because we think there's a random element in it and
24:55
Speaker 1: all the forces you'll see as we go through time,
24:57
Speaker 1: all the forces split off, and we think that those
25:00
Speaker 1: splittings are spontaneous, that they're essentially the result of one
25:04
Speaker 1: little quantum fluctuation which then gets propagated through the universe.
25:07
Speaker 1: You know, like when everybody sits down at a dinner table,
25:10
Speaker 1: do you drink from the glass to your left to
25:12
Speaker 1: your right? Well, if one person chooses left, then you know,
25:15
Speaker 1: everybody around them starts to choose left and it spreads
25:17
Speaker 1: across the whole dinner table. Right, they could have chosen
25:20
Speaker 1: to drink from the one to their right and then
25:22
Speaker 1: everyone would use that one. So one little fluctuation like
25:25
Speaker 1: that can propagate itself through the whole universe. And we
25:29
Speaker 1: don't know if gravity splitting off was inevitable or at
25:33
Speaker 1: what temperature it should have split off? We just don't know.
25:36
Speaker 1: We think gravity split off first because it's the weakest force,
25:39
Speaker 1: and so we think it would take the hottest temperature
25:42
Speaker 1: to combine all the forces. And then fourteen billion years later,
25:45
Speaker 1: everyone's like, is this my glasses? Is your glass? Did
25:49
Speaker 1: you drink from mine? Because I thought I had more
25:51
Speaker 1: wine left over? And then people are spitting up what
25:57
Speaker 1: And then it's it's like back to the big bank,
26:00
Speaker 1: all right, So things start to split off and cool down,
26:02
Speaker 1: and then we start to get more forces defined. Uh,
26:06
Speaker 1: and then what happens next? And then the next thing
26:08
Speaker 1: to split off is the strong force. So gravity split off,
26:12
Speaker 1: and then the strong force splits off. So now we
26:14
Speaker 1: have gravity, we have the strong force, and we have
26:16
Speaker 1: the electro weak force electro week being the combination of
26:20
Speaker 1: electromagnetism and the weak force. Remember still we have no particles,
26:24
Speaker 1: so these things aren't like forces that we think of
26:26
Speaker 1: today that are balancing particles around. It's just the fields
26:29
Speaker 1: now have different properties. They operate differently, they contain energy differently,
26:34
Speaker 1: they have different strengths. As the universe is coolest, so
26:37
Speaker 1: gravity split off, but it's not like bringing anything together
26:39
Speaker 1: because there is no thing. Well, gravity is doing what
26:42
Speaker 1: gravity does. It's you know, the bending of space. But
26:44
Speaker 1: you know, even talking about merging gravity with these other
26:48
Speaker 1: forces requires a conceptual leap that we haven't made yet,
26:51
Speaker 1: which is thinking about gravity as a quantum field, which
26:54
Speaker 1: we don't know how to do, especially in the early universe.
26:57
Speaker 1: So we are really out on very thin ice, or
27:00
Speaker 1: conceptually would like maybe if gravity can be unified with
27:04
Speaker 1: the other forces, then it was the first thing to
27:06
Speaker 1: split off of some mega force which might exist. And
27:09
Speaker 1: I can't emphasize enough how much respeculating cluelessly here, Okay, right, right,
27:14
Speaker 1: if gravity is a quantum field, this is kind of
27:16
Speaker 1: what we might expect. Yeah, yeah, exactly. But it's not
27:19
Speaker 1: like we have a firm prediction that we can like
27:21
Speaker 1: interrogate and explore. It's just like, hopefully somebody clever comes
27:25
Speaker 1: along and figures out how to make gravity quantum field
27:28
Speaker 1: and maybe it would work like this. All right, So
27:30
Speaker 1: now that and we split off the strong force, now
27:32
Speaker 1: we have more forces, and then something dramatic happens at
27:35
Speaker 1: around ten to the minus thirty two seconds. Right, Yeah,
27:39
Speaker 1: here's where the excitement really happens, and we don't know why,
27:42
Speaker 1: but we think at this point, for some reason, the
27:45
Speaker 1: universe started to expand extraordinarily rapidly, like space itself expanded,
27:50
Speaker 1: not just stuff flying through space slashing around, but space
27:54
Speaker 1: itself got stretched. Remember that space can expand based on
27:58
Speaker 1: the mass that's in it, Like we know the space
28:00
Speaker 1: is expanding right now. In their current universe is something
28:03
Speaker 1: called dark energy, which is creating new space, not just
28:07
Speaker 1: pulling on space, not pushing things further apart through space,
28:10
Speaker 1: but actually like adding new bits of space between galaxies.
28:15
Speaker 1: So that can definitely happen, and we know that it
28:17
Speaker 1: did happen in the very early which were created more space.
28:21
Speaker 1: The universe just started just creating at a crazy rate. Right.
28:24
Speaker 1: It's the kind of this kind of the bang in
28:26
Speaker 1: the Big Bang theory. Yeah, this is sort of the
28:28
Speaker 1: bang and the Big Bang theory. I mean, originally people
28:30
Speaker 1: thought of the Big Bang is like a dot and
28:32
Speaker 1: things explode through space. These days, we have this period
28:36
Speaker 1: we're talking about now, which we call inflation, and then
28:38
Speaker 1: we think of the hot Big Bang is basically at
28:40
Speaker 1: the very end of inflation. But you know, the terms
28:43
Speaker 1: are a little fuzzy, but essentially here you have the
28:46
Speaker 1: biggest bang. I mean, the universe expands by a ridiculous amount.
28:50
Speaker 1: It's ten to the seventy eight ten ten to zero.
28:55
Speaker 1: So you take a piece of space that's like a
28:58
Speaker 1: nanometer across, very very quickly, in like ten to the
29:02
Speaker 1: minus thirty two seconds, you expanded to a hundred trillion kilometers. Crazy.
29:07
Speaker 1: So in ten to the minus thirty two point zero
29:10
Speaker 1: zero zeros one seconds, the universe for some reason just
29:16
Speaker 1: was like come out of here. Yeah, exactly, And and
29:19
Speaker 1: we don't know why. We we have, like you know,
29:22
Speaker 1: given fancy names to this theory to make it sound
29:25
Speaker 1: like it's a thing we know how to deal with.
29:27
Speaker 1: We call the inflation theory. We think maybe it was
29:30
Speaker 1: generated by the inflaton field, but that's really just like saying, oh,
29:34
Speaker 1: you know, the answer is a fluctuation in my cluelessness field,
29:38
Speaker 1: like I really just don't know. For this into the
29:41
Speaker 1: framework of ideas, so it sounds clever, so they're like, oh,
29:46
Speaker 1: they blew up. And it could be, you know, that
29:49
Speaker 1: it's triggered by the electroweak breaking that like maybe breaking
29:53
Speaker 1: off the strong force from the electroweak force created the
29:56
Speaker 1: infloton field or settled the infloton field into a way
30:00
Speaker 1: that made it do this crazy expansion. But this is
30:03
Speaker 1: guessing upon guess. We are very confident that inflation happened.
30:07
Speaker 1: I mean the things that it predicts are very specific
30:10
Speaker 1: and very concrete. You know, like before inflation, the universe
30:14
Speaker 1: is very hot and dense, but not totally uniform because
30:18
Speaker 1: it's quantum mechanical, and so you get subspots that have
30:20
Speaker 1: like little quantum fluctuations of a little bit more density
30:23
Speaker 1: and quantum fluctuation is a little bit less density, really
30:26
Speaker 1: really tiny variations. But then this inflation is stretching, turns
30:31
Speaker 1: those little seeds of over densities into big structures which
30:35
Speaker 1: then form the structure of the universe. And we can
30:37
Speaker 1: do all those simulations and it describes very well what
30:40
Speaker 1: we see today is thing. And I guess one question
30:43
Speaker 1: is where did all the space come from? Like when
30:45
Speaker 1: you make space, does it require energy? Yeah, we don't
30:48
Speaker 1: really know. I mean, we know that the universe is
30:51
Speaker 1: not closed, and so an energy conservation is not required
30:55
Speaker 1: by general relativity to make space, you don't need energy. Maybe, well,
30:59
Speaker 1: you know space is energy, like space has energy in it.
31:02
Speaker 1: When you create space, it has all these fields, and
31:04
Speaker 1: those fields have energy in them, and so when you
31:07
Speaker 1: create space, it's like creating energy. So it's not something
31:10
Speaker 1: that we understand. It's not something we know how to do,
31:13
Speaker 1: or that we understand the rules about. We see it
31:15
Speaker 1: happening in our current universe. We don't understand the mechanism
31:18
Speaker 1: behind it. We call it dark energy because we're clueless.
31:21
Speaker 1: We know that it happened in the very early universe.
31:23
Speaker 1: Maybe it's the same mechanism, maybe it's something totally different.
31:27
Speaker 1: We really just don't know, all right, So now we're
31:29
Speaker 1: getting almost to the two microsecond mark, So let's finish
31:33
Speaker 1: off what happens in the first two microseconds, and then
31:35
Speaker 1: we'll go on to our next question. But first let's
31:38
Speaker 1: to get quick break, all right, Daniel, we just exploded
31:53
Speaker 1: the universe. We just went through inflation. In the first
31:57
Speaker 1: tent of the minus thirty two seconds, one ter became
32:01
Speaker 1: a hundred trillion kilometers. Now things are expanding like crazy.
32:06
Speaker 1: Quantum fluctuations make a huge difference. Now what happens now
32:10
Speaker 1: we finally get particles. Things have cooled down enough that
32:14
Speaker 1: the energy that's in the field is distinct and discretized,
32:17
Speaker 1: and you can follow it around. You can say, oh,
32:20
Speaker 1: this little blob of energy in the electron field is
32:23
Speaker 1: moving through space in a coherent way. You can call
32:26
Speaker 1: this an electron and the same for the other fields.
32:29
Speaker 1: And so you start to get particles made, and you
32:32
Speaker 1: get the last moment of breaking that we're aware of
32:35
Speaker 1: the electro weak force, which at the time was just
32:37
Speaker 1: one force. You know, there wasn't like a separate photon
32:41
Speaker 1: and W n z bosons acting separately. It was a
32:44
Speaker 1: single force with four of its own bosons. This field
32:47
Speaker 1: now breaks, and it breaks into electromagnetism and the weak force.
32:51
Speaker 1: It becomes two forces. It becomes two forces that are
32:54
Speaker 1: still closely connected. I mean, they're two broken pieces of
32:57
Speaker 1: a larger force. You can sort of like fit them
32:59
Speaker 1: together roughly the way you can fit continents together, you know,
33:02
Speaker 1: like you can think of the mega continent breaks into
33:05
Speaker 1: little continents and now they're a little different, but the
33:07
Speaker 1: contours sort of match, and so you can think about
33:09
Speaker 1: their history. Right, And this is another example spontaneous symmetry.
33:13
Speaker 1: Breaking the Higgs field gives the photon no mass, and
33:17
Speaker 1: it gives the ws and z s a lot of mass,
33:20
Speaker 1: So all of a sudden, the weak force becomes really
33:23
Speaker 1: really weak. Interesting, and so then that's what kind of
33:26
Speaker 1: gives rise to the Higgs field, which is the one
33:29
Speaker 1: that gives mass to everything. Yeah, so the Higgs field,
33:32
Speaker 1: like all the other field started out really hot. It
33:34
Speaker 1: was cooling down and cooling down, and most of the
33:37
Speaker 1: other fields they like settled down to zero, but the
33:39
Speaker 1: Higgs field got stuck, got stuck at a certain point
33:42
Speaker 1: where it couldn't go any lower because it has a
33:44
Speaker 1: really weird shape to It's like you know, on the
33:46
Speaker 1: edge of a canyon wall. It's got a little like
33:49
Speaker 1: dip in it, so you can get stuck in a
33:51
Speaker 1: little like on the precipice, like a little buzz right,
33:54
Speaker 1: And it got stuck there. And because it got stuck
33:57
Speaker 1: there and not somewhere else, it gave mass to the
34:00
Speaker 1: ws and disease, but not the photon and also to
34:02
Speaker 1: the other part of it. So all the other particles
34:05
Speaker 1: their mass then gets fixed because the Higgs field got
34:08
Speaker 1: stuck at this value. And before so before that we
34:10
Speaker 1: didn't have mass, or we just didn't have like consistent mass,
34:13
Speaker 1: or you can't even talk about mass. It's harder to
34:16
Speaker 1: talk about mass before. The particles really are like separate,
34:18
Speaker 1: identifiable spots. But the mass of the particles depends on
34:22
Speaker 1: the energy of the Higgs field. So as the universe
34:24
Speaker 1: is cooling down and the Higgs field is cooling down,
34:26
Speaker 1: you can think of it as like the masses of
34:28
Speaker 1: the particles are decreasing because the Higgs field is cooling down.
34:32
Speaker 1: All right, So now all of our forces are in motion.
34:35
Speaker 1: Now they're in play, and particles now exist, which is
34:39
Speaker 1: crazy to think about that. We didn't have particles before. Yeah,
34:43
Speaker 1: and now they have mass or they interact with the
34:45
Speaker 1: Higgs field, and and so is that then? Kind of
34:49
Speaker 1: is that it like is it a straight line from
34:51
Speaker 1: there to here? Or are there there still things we
34:54
Speaker 1: don't know. There's a lot of things we don't know,
34:56
Speaker 1: but it's basically a straight line. I mean, now you
34:57
Speaker 1: have particles, and the interactions in play are the ones
35:00
Speaker 1: we're familiar with. There's electromagnetic fields, the weak force, the
35:03
Speaker 1: strong force, there's gravity. But you know, it's still pretty
35:06
Speaker 1: hard to understand, Like it's a hot, dense and nasty mess.
35:09
Speaker 1: Like it's mostly quarks and leftons, but they are too
35:13
Speaker 1: hot to form any larger particles, Like you don't have
35:15
Speaker 1: protons and neutrons and stuff like that, which are bound
35:18
Speaker 1: states books just quarks quarks and flying around annihilating each other,
35:23
Speaker 1: constantly turning into photons, turning back into particles. It's still
35:27
Speaker 1: hot and dense, and then things are cooling off, so
35:30
Speaker 1: like you know about after one micro second you get
35:33
Speaker 1: this cork glue on plasma. Things start to cool off,
35:36
Speaker 1: and then you get things like protons and neutrons and whatever.
35:39
Speaker 1: And there's a really interesting mystery there about like what
35:42
Speaker 1: happened to all the anti matter. If everything was symmetric,
35:46
Speaker 1: you would expect the fields to create like as much
35:48
Speaker 1: matter and antimatter should all annihilate into a universe filled
35:51
Speaker 1: with light. But instead there was some asymmetry there. We
35:54
Speaker 1: ended up with like a little bit more matter than antimatter.
35:57
Speaker 1: Most of it is gone, but a little bit of
35:59
Speaker 1: matter or was left, and that's what led in a
36:02
Speaker 1: straight line to where we are today. I think the
36:04
Speaker 1: lesson here is a lot happened in the first two
36:06
Speaker 1: hundred microseconds. We missed the big party. I just feel
36:11
Speaker 1: like we went through an hour of just to cover
36:14
Speaker 1: a two d microseconds. That's amazing, So a lot happened, right,
36:17
Speaker 1: and a lot could have happened. Yeah, the history of
36:19
Speaker 1: the universe has been pretty boring ever since. You know,
36:23
Speaker 1: like most of the excitement was in the first few
36:25
Speaker 1: tiny slices of time, and ever since then it's been
36:29
Speaker 1: pretty slow. But you know, think about it, like on
36:32
Speaker 1: the cosmic time scale, like trillions and quadrillions of years,
36:36
Speaker 1: it could be that, you know, intelligent species in septillion years.
36:41
Speaker 1: Think about the first few billion years of the universe
36:44
Speaker 1: as like, you know, the first moments, because you know,
36:47
Speaker 1: it could be that the universe is very different in
36:49
Speaker 1: a trillion years, that it's all just black holes separated
36:52
Speaker 1: by vast distances or something else forms. You know, there's
36:55
Speaker 1: so many fascinating emergent phenomena they're really hard to anticipate,
37:00
Speaker 1: and so you know, maybe this will seem exciting to
37:03
Speaker 1: people who come much much later. Yeah, I'm sure they'll say, like,
37:06
Speaker 1: you know, that day where they post the two hundred
37:08
Speaker 1: episode of Daniel and Horge Explained the Universe, that's the
37:11
Speaker 1: equal zero to us. That's when that's when the party
37:15
Speaker 1: really started. Before then, it's not even really worth there,
37:21
Speaker 1: all right, Well, I think the answer is a lot
37:23
Speaker 1: happened in the first two hundred microseconds of the universe,
37:26
Speaker 1: which is amazing. All right, we have one more question here.
37:30
Speaker 1: I think we might have to talk about it in
37:32
Speaker 1: two hundred microseconds, Daniel. But the question is pretty interesting.
37:36
Speaker 1: It's something I thought about as we try to brainstorm
37:39
Speaker 1: ideas for this episode. But the question is what can
37:42
Speaker 1: we find within two hundred light years of Earth? So
37:47
Speaker 1: I guess, first of all, how much is two hundred
37:49
Speaker 1: light years? Like a few Brazilian kilometers? Yeah, a light
37:52
Speaker 1: year is really far. So a light year is like
37:55
Speaker 1: nine point five times ten to the twelve kilometers. That's
38:00
Speaker 1: why we use light years, because the distances in the
38:02
Speaker 1: universe are so vast the kilometers become an absurd unity.
38:06
Speaker 1: So it's like two hundred million million kilometers. So if
38:09
Speaker 1: you could hop in a spaceship and go two hundred
38:11
Speaker 1: million million kilometers, where could we go visit? Yeah? So
38:15
Speaker 1: mostly the universe is empty. You know, you pick our
38:17
Speaker 1: random spot outside the Solar system and you go in
38:21
Speaker 1: a straight line, you'll see nothing for two hundred light years. Like,
38:24
Speaker 1: it's just not much there. The universe is not very
38:27
Speaker 1: dense anymore. And you know, I read these science fiction
38:30
Speaker 1: novels about people flying through space and like hitting asteroid
38:33
Speaker 1: fields and bumping into stars, and I'm like, it's just
38:36
Speaker 1: not that much stuff out there. Likely, No, It's like
38:39
Speaker 1: swimming in the ocean. How often do you really encounter
38:42
Speaker 1: a desert island? Like? Really not that often? Oh, I see,
38:45
Speaker 1: that's a good analogy. Like if you were in the
38:47
Speaker 1: middle of the ocean and you went a few hundred kilometers,
38:51
Speaker 1: you know, what are the chances that you'll hit another island?
38:53
Speaker 1: Pretty small? Yeah, pretty small. It's mostly just ocean out there.
38:56
Speaker 1: But there are things out there, and mostly within two
38:59
Speaker 1: hundred light years of Earth. There are a bunch of stars,
39:01
Speaker 1: but you know, not that close. Like the closest star really,
39:04
Speaker 1: once you leave our Solar system, the closest thing that
39:07
Speaker 1: you can find to our Solar system is a star
39:09
Speaker 1: called Proximus Centauri. It's about four point two light years away.
39:13
Speaker 1: It's done the name of an Avengers villain. I feel
39:16
Speaker 1: like I've heard that name before. Are you auditioning to
39:19
Speaker 1: be in the next Marvel movie? That's what happening here?
39:22
Speaker 1: To be the voiceover? I think Proximate can Centauri, the
39:24
Speaker 1: Marvel villain can do two hundred accents. So if you
39:27
Speaker 1: really want to audition, then we've got to hear some accents. Yeah,
39:30
Speaker 1: all right, so that's the nearest star. I guess how
39:33
Speaker 1: how many stars can we find within two hundred light years?
39:35
Speaker 1: You know, surprisingly, you can find a lot of stars. Now,
39:38
Speaker 1: on one hand, stars are not very dense. I mean,
39:41
Speaker 1: in our galactic neighborhood, there's about one star per two
39:45
Speaker 1: hundred and fifty cubic light years. But as the radius
39:49
Speaker 1: of your sphere grows, the volume of it goes up
39:52
Speaker 1: very quickly, goes up with radius cubed. So a sphere
39:56
Speaker 1: with radius two hundred light years has a lot of
39:59
Speaker 1: cubic light years, like thirty million. If you go at
40:03
Speaker 1: about two hundred light years, there's something like, you know,
40:05
Speaker 1: tens of thousands or maybe a hundred thousand stars in
40:09
Speaker 1: that volume. Really, yeah, I could visit a hundred thousand
40:12
Speaker 1: stars within two hundred light years. Yes, But you know,
40:15
Speaker 1: if you travel in a straight line two hundred years,
40:17
Speaker 1: you would probably find very small number of stars. If
40:20
Speaker 1: you completely visited a spear with radius two hundred light years,
40:25
Speaker 1: would be a hundred thousand stars there. But you know,
40:27
Speaker 1: like the list of destinations I can go. Is it's
40:30
Speaker 1: like a hundred thousand stars. Yeah, there's a lot of options.
40:33
Speaker 1: I mean, if you like decisions and you like choices,
40:36
Speaker 1: then there's a lot of options. Most of them are
40:37
Speaker 1: pretty far away. I mean, the vast majority of those
40:40
Speaker 1: hundred thousand are on a thin shell on the outside
40:43
Speaker 1: of that sphere, mostly because that's where most of the
40:46
Speaker 1: volume is. But they say that, you know, about one
40:48
Speaker 1: in five star has an Earth like planet, So we're
40:51
Speaker 1: talking about like there's twenty thousand earthlike planets I could visit. Yeah,
40:55
Speaker 1: there are definitely a lot of Earth like planets, and
40:57
Speaker 1: we think that most of those solar systems have planets
41:00
Speaker 1: like multiple planets, which is fascinating. We don't know a
41:03
Speaker 1: lot about like what those solar systems look like, and
41:05
Speaker 1: how often do you get big gas giants and rocky
41:08
Speaker 1: inner worlds, And is our solar system unusual or totally typical.
41:12
Speaker 1: Something that is unusual about our solar system that you'll
41:14
Speaker 1: discover as you look around in the solar system is
41:18
Speaker 1: how many solar systems have multiple stars. Like in the
41:21
Speaker 1: closest fifteen light years is like fifty something stars, and
41:25
Speaker 1: about half of them are single stars, just like a
41:28
Speaker 1: star with planets around it. But there's like ten of
41:30
Speaker 1: them that are binary systems, like two stars orbiting each
41:34
Speaker 1: other and then planets around the wo that's common. That's common.
41:37
Speaker 1: And even within fifteen light years there are four systems
41:41
Speaker 1: that are trinary systems that have three stars in orbit
41:45
Speaker 1: around each other. That's pretty cool. So in Star Wars
41:48
Speaker 1: when Luke is looking out at the two suns on
41:50
Speaker 1: the horizon, that's like maybe more common than you think.
41:53
Speaker 1: That's not rare. It's a lot more common than you think.
41:56
Speaker 1: And if you think about how things form, you start
41:58
Speaker 1: from a big cloud and things cold less, and so
42:00
Speaker 1: it's not necessary for its all coalesceent to one really
42:04
Speaker 1: big blob in the center of a solar system. If
42:06
Speaker 1: you have like a little bit of density here, in
42:08
Speaker 1: a little bit of density there, it can form two.
42:10
Speaker 1: Or if two stars form close enough to each other,
42:13
Speaker 1: they'll pull on each other and form one of these systems.
42:16
Speaker 1: Some listeners send me an awesome question recently. He said,
42:19
Speaker 1: are there any stars out there that have sort of
42:22
Speaker 1: two planetary disks, Like one planetary disc aligned in one
42:26
Speaker 1: way and then the second one aligned you know, at
42:28
Speaker 1: an angle to it like two hula hoops. Yeah, like
42:31
Speaker 1: two hula hoops. And I don't know if one, but
42:34
Speaker 1: there's no reason to think there couldn't be. Like if
42:37
Speaker 1: you had two solar systems that sort of merged and
42:39
Speaker 1: the stars combined in the center, or you get a
42:41
Speaker 1: binary star system in the center, they could keep each
42:44
Speaker 1: of their planetary disks and it would be at different angles,
42:47
Speaker 1: and so that could totally happen. I think that would
42:50
Speaker 1: be an awesome setting for a science fiction right, but
42:52
Speaker 1: every year you go around the Sun, you'll be like,
42:54
Speaker 1: watch out for those other this other planet is would
42:56
Speaker 1: be a drama every year. It would have to work
43:00
Speaker 1: like clockwork, but it might make for some pretty cool
43:02
Speaker 1: nighttime observations. All right, cool, So there's about a hundred
43:05
Speaker 1: thousand stars within two hundred light years. What else can
43:08
Speaker 1: we find in this bubble? Well, it's mostly it. I
43:11
Speaker 1: mean in the galaxy we have stars. Of course, we
43:14
Speaker 1: have gas clouds, which are the birthplace of stars, but
43:18
Speaker 1: there aren't any of those within two hundred light years.
43:20
Speaker 1: Like the closest one is about four hundred and something
43:23
Speaker 1: light years away. It's called Taurus, and it's where stars
43:26
Speaker 1: are being born. There are stars in there. They're like
43:28
Speaker 1: one or two million years old, But we don't have
43:31
Speaker 1: any of those big blobs inside our like two hundred
43:34
Speaker 1: light year windows, because like a cluster itself is pretty big.
43:39
Speaker 1: It's almost as big as two hundred light years. Yeah,
43:42
Speaker 1: some of these gas clouds are are hundreds of light
43:44
Speaker 1: years across. They're really vast. There's like the birthing regions
43:47
Speaker 1: of stars. But there is a cluster of stars. Like
43:51
Speaker 1: there's a big major cluster of stars. It's called the
43:53
Speaker 1: Hyades cluster, and it's about a hundred and fifty light
43:56
Speaker 1: years away. It's like six hundred something million years old,
44:00
Speaker 1: and it's just like a big blob of stars that
44:02
Speaker 1: are all together. It's probably comes from a really dense
44:05
Speaker 1: region of of gas and molecules that got formed early on,
44:09
Speaker 1: and so that's like a big blob of stars. So
44:12
Speaker 1: I see, oh wow, that must be pretty amazing to
44:14
Speaker 1: go near or to visit there. Yeah, And you know,
44:16
Speaker 1: if you're looking to visit a lot of stars and a
44:18
Speaker 1: a lot of planets at once, it's probably a good destination.
44:20
Speaker 1: On the other hand, it's a hundred and fifty light
44:22
Speaker 1: years away, so it's to take you a while to
44:25
Speaker 1: get there. Well, I think this kind of tells you
44:27
Speaker 1: how big the universe is, you know, two hundred light years,
44:30
Speaker 1: Like that's even like if we prolong human life and
44:34
Speaker 1: double it and was able to go at the speed
44:36
Speaker 1: of light, that's as far as like any one person
44:38
Speaker 1: could probably go without any kind of special awards beat
44:42
Speaker 1: or wormhole, right. Yeah, And you know the thing that's
44:45
Speaker 1: furthest away, the human device that's furthest away from the
44:48
Speaker 1: Solar system right now is voyage or one. It's traveling
44:52
Speaker 1: at sixty one thousand kilometers per hour, and if it
44:56
Speaker 1: kept going, it would take another seventy thousand years to
44:59
Speaker 1: reach the nearest star. Like, these distances are just incredible,
45:05
Speaker 1: and it's already eighteen billion kilometers away from us, but
45:09
Speaker 1: that's just like a tiny fraction of the distance to
45:12
Speaker 1: approximates centauri. I see, seventy thousand years, that's like what
45:16
Speaker 1: three thousand more episodes, Daniel, I got all those ideas. Yeah,
45:21
Speaker 1: I've sketched them out already. You would really like to
45:24
Speaker 1: work ahead. Yeah, And you know, if you think about
45:28
Speaker 1: the larger context you know of our galaxy. Our galaxy
45:31
Speaker 1: is a hundred thousand light years across. So a bubble
45:33
Speaker 1: two hundred light years is really a tiny neighborhood. You know,
45:37
Speaker 1: the Sun itself is just like is twenty something thousand
45:40
Speaker 1: light years from the center of the galaxy. So even
45:43
Speaker 1: like the most we might right now could imagine traveling
45:46
Speaker 1: to for a single human is is a drop in
45:49
Speaker 1: the bucket of the size of our galaxy. Yeah, if
45:52
Speaker 1: you were looking at a map of the galaxy, you
45:54
Speaker 1: wouldn't even notice that distance, right, Wow, alright, Well, I
45:58
Speaker 1: feel like we covered a lot in the first two
46:01
Speaker 1: seconds this podcast. And uh, we also got this kind
46:05
Speaker 1: of amazing view of how big the galaxy is and
46:09
Speaker 1: spaces and how empty it is. It's incredible how dense
46:12
Speaker 1: and hot the universe used to be and how big
46:14
Speaker 1: and cold it is today, and yet it's still filled
46:17
Speaker 1: with mystery and our whole concept of the universe, where
46:20
Speaker 1: it came from, how it began, what it looks like now,
46:23
Speaker 1: what's out there could be totally rocked by discoveries that
46:27
Speaker 1: are coming, discoveries made by scientists working today, over by
46:30
Speaker 1: somebody out there listening to this podcast right now that's thinking, Hey,
46:34
Speaker 1: maybe I could crack one of the biggest questions in
46:37
Speaker 1: the universe because you know you could. Yeah, yeah, and
46:39
Speaker 1: then we'll cover it here in our episode. That's right,
46:44
Speaker 1: And so I want to say a personal thank you
46:46
Speaker 1: to all the fans and listeners for tuning into all
46:48
Speaker 1: these episodes, for sending us supportive messages, for letting us
46:51
Speaker 1: know that you're enjoying what you're hearing, and for sharing
46:54
Speaker 1: with us all of your wonder and your curiosity, and
46:57
Speaker 1: for going on this crazy journey with us. Absolutely believe
47:00
Speaker 1: we wouldn't be doing this without you. And thanks also
47:03
Speaker 1: for letting all your friends know and all your context
47:05
Speaker 1: note because the more people that are listening, the more
47:08
Speaker 1: episodes we can make. All right, well, thanks again for
47:11
Speaker 1: helping us celebrate our two hundred episode. We hope you
47:14
Speaker 1: enjoyed that. See you next time. Thanks for listening, and
47:25
Speaker 1: remember that Daniel and Jorge Explain the Universe is a
47:28
Speaker 1: production of I Heart Radio. For more podcast For my
47:31
Speaker 1: Heart Radio, visit the I Heart Radio app, Apple Podcasts,
47:35
Speaker 1: or wherever you listen to your favorite shows