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Do black holes destroy information? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Daniel, I've got a black hole question for you.
0:11
Speaker 1: Are you still hoping to catch and raise a black
0:13
Speaker 1: hole as a pet in your backyard? I can't confirm
0:16
Speaker 1: or deny that, But my question is what happens to
0:19
Speaker 1: the stuff I put into the black hole? Is this
0:21
Speaker 1: a question you already asked the folks at pet Smart. Yeah.
0:24
Speaker 1: You know, like, say, if I drop a banana into
0:26
Speaker 1: a black hole, what what happens to it? Is it
0:29
Speaker 1: gone forever? My advice is don't do it? Which part
0:32
Speaker 1: raise a black hole or throw a banana into it?
0:36
Speaker 1: Because I may have done both already. What's the difference?
0:39
Speaker 1: I mean, if you feed a black hole, it will grow,
0:42
Speaker 1: and a growing black hole will eat more, and eventually
0:44
Speaker 1: it will eat your house and then mine. Okay, so
0:47
Speaker 1: it's not a good idea to use a black hole
0:49
Speaker 1: to make banana's booties. Officially, no, not a good idea. Hi,
1:09
Speaker 1: I'm poor. Hey, I'm a cartoonist and the creator of
1:11
Speaker 1: PhD comics. Hi, I'm Daniel. I'm a particle physicist, and
1:14
Speaker 1: I have never created a black hole to my knowledge.
1:17
Speaker 1: How do you know, Daniel? Maybe you do it in
1:19
Speaker 1: your sleep by accident. Hey, I can't be responsible for
1:22
Speaker 1: all incidental black holes I accidentally create, right, I mean,
1:26
Speaker 1: there's got to be some legal principle there. Do you
1:28
Speaker 1: ever take homes any work by accident, you know, like
1:30
Speaker 1: you guys suddenly bring home some particles or some black
1:33
Speaker 1: holes that were created at the LHC. Yeah, sometimes I
1:35
Speaker 1: go home with a few extra protons in my pocket.
1:38
Speaker 1: Nobody even notices that doesn't sound good. But welcome to
1:42
Speaker 1: our podcast, Daniel and Jorge Explain the Universe, a production
1:45
Speaker 1: of I Heart Radio, in which we tell you all
1:48
Speaker 1: about the mysteries of the university, incredible cosmic questions that
1:52
Speaker 1: still make scientists puzzled, the things that we all wonder
1:56
Speaker 1: about this incredible, beautiful universe that we live in that
1:59
Speaker 1: we all desperately like to understand. Yeah. I take home
2:03
Speaker 1: work all the time, Daniel, because I work from home
2:06
Speaker 1: my cartoonist. So I think you take your home to
2:08
Speaker 1: work then, don't you You know the tomato tomato, it's
2:12
Speaker 1: all the same thing. But that's right. This is our
2:14
Speaker 1: podcast about the universe and all the amazing and mysterious
2:18
Speaker 1: things that are out there for us to discover. That's right,
2:21
Speaker 1: all those weird things floating in the cosmos doing strange, violent,
2:25
Speaker 1: incredible stuff and our attempts as lowly humans to understand them.
2:30
Speaker 1: Is it really possible to unravel the mysteries of the
2:33
Speaker 1: universe and lay them out inside a human mind. We
2:36
Speaker 1: will find out today and tomorrow and the next hundred
2:40
Speaker 1: episodes of our podcast. Yeah, because you know, it sometimes
2:43
Speaker 1: feels like we're building this model of the universe kind
2:45
Speaker 1: of like we're building a whole universe kind of inside
2:48
Speaker 1: of our heads and our physics theories, almost like a hologramma.
2:52
Speaker 1: That's right. It's incredible to imagine that the whole external universe,
2:56
Speaker 1: if it even exists, might be describable inside in mind, right,
3:01
Speaker 1: Like you could represent it somehow in terms of arrangements
3:04
Speaker 1: of neurons, right, and as I think the kind of
3:07
Speaker 1: idea that makes people think, like maybe the entire universe
3:10
Speaker 1: is actually just a projection of some other kind of
3:12
Speaker 1: physical arrangement. Right. Yeah, I've always wondered like maybe our
3:16
Speaker 1: brains just aren't equipped to like understand the universe. Do
3:19
Speaker 1: you ever wonder about that? Oh, I'm almost certain that
3:21
Speaker 1: we are not capable of understanding the universe at its
3:23
Speaker 1: deepest level. So are we doomed to always not know
3:27
Speaker 1: the universe. I think there's never going to be a
3:30
Speaker 1: point where we're satisfied that we think we understand and
3:33
Speaker 1: you know, imagine the kind of super intelligence that would
3:36
Speaker 1: be necessary to like fully grasp with the universe. I
3:39
Speaker 1: think about your dog. Your dog is intelligent, but it
3:42
Speaker 1: certainly doesn't understand all the physics of the universe. And
3:47
Speaker 1: so compared to some super intelligent aliens out there, we
3:50
Speaker 1: are as small as dogs, and there's no way that
3:52
Speaker 1: we could understand the universe at the level that they do.
3:55
Speaker 1: And so you essentially have to be infinitely intelligent to
3:58
Speaker 1: understand the whole university thing. And couldn't infinite intelligence exist
4:02
Speaker 1: in the universe that that would be so that would
4:04
Speaker 1: be a lot. It would create an intelligence black hole
4:07
Speaker 1: inside its mind because you can't store that much information
4:10
Speaker 1: or that much smart in a small space. Man, we've
4:14
Speaker 1: just covered dogs and black holes and like the first
4:17
Speaker 1: three minutes and including brains. But yeah, so we talked
4:21
Speaker 1: about all of the mysterious things, and one of the
4:23
Speaker 1: favorite mysterious things that we like to talk about our
4:26
Speaker 1: black holes because they're so mysterious and it seems like,
4:30
Speaker 1: you know, that there were these black pockets in almost
4:33
Speaker 1: their own universes, and it seems like anything you throw
4:36
Speaker 1: into it can never ever come out. And they're especially
4:39
Speaker 1: wonderful and fascinating because they came out of the human
4:42
Speaker 1: mind initially. It's not something we saw in the universe.
4:45
Speaker 1: It's an idea we had. We said, if the laws
4:47
Speaker 1: of physics are the way we think they are, then
4:50
Speaker 1: these things should exist. So we like mapped something inside
4:54
Speaker 1: our minds out into the universe and then went out
4:56
Speaker 1: and actually found them. I mean it's incredible, right that
5:00
Speaker 1: think that our understanding the universe could be so sophisticated
5:03
Speaker 1: and impressive that we can predict crazy new bonker stuff
5:06
Speaker 1: out there which turns out to be real. I think
5:09
Speaker 1: that's really impressive. Yeah, yeah, good jobs, physicists. Even though
5:12
Speaker 1: we are dogs compared to intelligently nothing against dogs. Of course,
5:17
Speaker 1: dogs very smart. That's why I chose them physics example,
5:20
Speaker 1: and not cats. Right, I think cats are smarter. They're
5:23
Speaker 1: not smarter than dogs. Man, you cannot train a cat.
5:26
Speaker 1: That's proof number one. That's cats are not smarter than dogs.
5:29
Speaker 1: Maybe like cats are mathematicians and dogs are physicists. Would
5:33
Speaker 1: you say that's a fair, fair comparison. Well, if you're
5:36
Speaker 1: saying that dogs are smarter than cats, that I agree
5:38
Speaker 1: with you. Masticians are just sneakier, that's right now. But
5:45
Speaker 1: black holes are a fascinating mystery and one that began
5:49
Speaker 1: inside the human brain, but one that we still don't
5:52
Speaker 1: really understand. I mean, we found them, we see them
5:54
Speaker 1: out there, but it's a continuous source of mystery and
5:57
Speaker 1: puzzlement for people everywhere and for scientists. Yeah, and it's
6:01
Speaker 1: amazing that we've seen it, like we've found one, Like
6:03
Speaker 1: they took pictures of one sort of last year, and
6:06
Speaker 1: it's like it's real, it's there, you can see it,
6:08
Speaker 1: and it looks like what we thought they looked like.
6:10
Speaker 1: That's right. The picture of the black hole shows you
6:12
Speaker 1: all the incredible gas swirling around it that's trying desperately
6:16
Speaker 1: to avoid falling into the black hole and in the
6:19
Speaker 1: process is bouncing around against all the other gas and
6:21
Speaker 1: emitting lots of radiations. So we're not seeing the black
6:24
Speaker 1: hole directly, you know, although we see a black spot there,
6:27
Speaker 1: we're seeing mostly the swirling, chaotic, crazy gas that's surrounding. Yeah.
6:32
Speaker 1: I guess you're right, because I mean, we see the
6:34
Speaker 1: black center, but there's nothing to see there because nothing
6:37
Speaker 1: can come out, or at least that's the idea of
6:39
Speaker 1: a black hole. And so the question then kind of
6:42
Speaker 1: becomes what happens to the stuff that goes into it?
6:46
Speaker 1: Is it gone forever or cannedy recovered? Yeah? Is that
6:50
Speaker 1: stuff just like hanging out inside the black hole having
6:53
Speaker 1: a great time with all the other stuff? Does it
6:55
Speaker 1: get squeezed into some new form of matter? Is it
6:58
Speaker 1: all in a singularity in the middle. It's of the
7:00
Speaker 1: deepest questions in physics what's going on inside a black
7:03
Speaker 1: hole and what happened to the stuff that fell in?
7:06
Speaker 1: So today on the podcast we'll be asking the question
7:13
Speaker 1: those a black hole destroy information? I guess that's an
7:18
Speaker 1: interesting question because you know, it's kind of like asking
7:21
Speaker 1: what happens to stuff that goes in, Like does it
7:23
Speaker 1: get destroyed like obliterated? Does it become pure energy, unadultered,
7:29
Speaker 1: unfiltered energy that you can't make out what it is?
7:32
Speaker 1: Or does it you know, does a cork stay a
7:34
Speaker 1: cork inside of the black hole? And does it still
7:37
Speaker 1: fly around and doesn't even know it's in a black hole? Yeah?
7:39
Speaker 1: I mean, are you wondering about what happened to that
7:41
Speaker 1: banana you dropped into your black hole. I'm still wondering
7:43
Speaker 1: about my banana, Daniel. I want it back. My dog
7:46
Speaker 1: needs today. Do you like eating bananas when they're black,
7:49
Speaker 1: because that's probably what happened to your back. You mean
7:52
Speaker 1: it turned into a movie basically. Basically, But it's a
7:55
Speaker 1: fascinating question, like when something goes into a black hole.
7:58
Speaker 1: Is a black hole like a cosmic hard drive? Does
8:01
Speaker 1: it like just compress everything into some new arrangement but
8:05
Speaker 1: effectively keeping track of all the particles that came in,
8:08
Speaker 1: or is it actually deleting stuff from the universe, turning
8:12
Speaker 1: into some new configuration that doesn't have any information about
8:15
Speaker 1: what happened before it. That's a fascinating question. Yeah, and
8:18
Speaker 1: so we have a lot to impact here about black
8:20
Speaker 1: holes and information. But at first we, as usually, we
8:24
Speaker 1: were wondering how many people out there had heard of
8:27
Speaker 1: this question of whether black holes keep or destroy information?
8:31
Speaker 1: And so, as usual, Daniel went out there and ask
8:34
Speaker 1: people on the internet what they thought of this question.
8:36
Speaker 1: That's right, So thank you to everybody who have volunteered
8:38
Speaker 1: to answer random questions. If you're willing to participate and
8:42
Speaker 1: like to hear your uninformed speculation on the podcast right
8:45
Speaker 1: to us two questions at Daniel and Jorge dot com
8:49
Speaker 1: YouTube can answer these random questions. Think about it for
8:51
Speaker 1: a second, and what do you know about information and
8:54
Speaker 1: black holes and what goes into them? Here's what people
8:57
Speaker 1: had to say. I think the information diss inside a
9:00
Speaker 1: black hole. My understanding of Hawking radiation is that when
9:04
Speaker 1: a particle interacts with the black hole, information is lost.
9:08
Speaker 1: Therefore the black hole behaves like a garbage disposal. Ah,
9:13
Speaker 1: so I do know a little bit about this. So
9:15
Speaker 1: I read a book by Leonard Suskin which was talking
9:18
Speaker 1: about the black hole wars. Stephen Hawkins believe that they
9:22
Speaker 1: did disappear. Information did disappear, and the Suskin said it didn't.
9:27
Speaker 1: And I think it's started to do with holographic principle
9:31
Speaker 1: that basically all the data stays on the event arising. Yes,
9:34
Speaker 1: information disappears from black holes because they lose mass through
9:37
Speaker 1: Hawking radiation. They're more like garbage disposes than hard drives,
9:41
Speaker 1: since you can't retrieve any information that's stored in them.
9:44
Speaker 1: Um my guests would be that once an object is
9:46
Speaker 1: sucked into a black hole. It is obliterated into its
9:49
Speaker 1: most smallest particles that exist, and those things float around
9:53
Speaker 1: and mess around with other particles and probably no longer
9:55
Speaker 1: resemble whatever it is that they used to make up planets, bananas,
9:59
Speaker 1: bunnies or whatever it is. I think they like store
10:02
Speaker 1: information and then eventually, in like trillions and trillions and
10:06
Speaker 1: trillions of years, there's like hawking radiation that radiates, you know,
10:11
Speaker 1: and out in black holes go away. As far as
10:14
Speaker 1: I understand, physics falls apart inside a black hole. I've
10:18
Speaker 1: read that information doesn't disappear as such, and that all
10:25
Speaker 1: the information inside the black hole would be somehow readable
10:31
Speaker 1: on the horizon. Whatever goes in there just gets squished
10:35
Speaker 1: into a really tiny small space. So I'd probably say
10:39
Speaker 1: they're more like a garbage disposal. What goes in doesn't
10:42
Speaker 1: come out, I don't think so. I think it depends
10:45
Speaker 1: at the center of a black hole is which we
10:48
Speaker 1: don't know. If it's an infinite density single point, then
10:53
Speaker 1: it's probably more like a garbage disposal. But if it's not,
10:57
Speaker 1: then I would assume information can enter it and just
11:00
Speaker 1: gets trapped. I'm gonna equivocate on this, and so I
11:03
Speaker 1: shall leave it to my learned colleagues Daniel Watson and
11:08
Speaker 1: Hua Champ perhaps to answer that all so, I don't
11:13
Speaker 1: think that information disappears into the black hole. I think
11:17
Speaker 1: information is recorded on the edge of black hole. Information
11:22
Speaker 1: cannot disappear, like energy cannot disappear. All right, not a
11:26
Speaker 1: good outlook for what happens to stuff that goes into
11:29
Speaker 1: the black hole. Nobody nobody thinks it's hanging out happily inside.
11:33
Speaker 1: Nobody thinks that you're gonna eat that banana. I like that.
11:35
Speaker 1: There's basically every answer here. Information disappears, information doesn't disappear,
11:40
Speaker 1: information is radiated out, and they're basically garbage compactors. That's
11:44
Speaker 1: a wonderful variety of answers here. Thank you to everybody
11:47
Speaker 1: who participated, a wonderful variety of analogies here, Like is
11:51
Speaker 1: a garbage compactor? Is it a garbage disposal? Is it
11:54
Speaker 1: a recycling being? I don't think the universe recycles. I
12:00
Speaker 1: don't think it's like plastic in this black hole. Please,
12:03
Speaker 1: And you know what, if black holes are just the
12:05
Speaker 1: universe's compost, interesting they could be right. They break stuff
12:09
Speaker 1: down and maybe they store it for later for a
12:12
Speaker 1: universe garden, a star garden or story for never that's
12:16
Speaker 1: maybe the problem. Well, until the universe collapses and then
12:18
Speaker 1: everything gets too cycled. Right, that's a very optimistic view
12:23
Speaker 1: of what's going to happen to your banana. Well, this
12:25
Speaker 1: is an interesting topic, and so let's jump right into it.
12:27
Speaker 1: This might take a while because some of the things
12:30
Speaker 1: that we need to talk about include information and quantum mechanics.
12:33
Speaker 1: And so before we sort of get into the idea
12:35
Speaker 1: of what happens to information that goes into a black hole,
12:40
Speaker 1: let's talk about kind of information in general and how
12:43
Speaker 1: that works in a quantum reality. That's right, because one
12:47
Speaker 1: of the mysteries of black holes is what happens to
12:49
Speaker 1: the information that goes into them. And so first we
12:52
Speaker 1: have to understand, like what is information and what does
12:55
Speaker 1: quantum mechanics say about that information? Right? So, information is
13:00
Speaker 1: kind of like the arrangement of things, like the physicist.
13:02
Speaker 1: Information is not like ones and zeros or it's not like, yeah,
13:06
Speaker 1: you know a file or a number. It's more like
13:09
Speaker 1: the arrangement of things, right, Yeah, And it can be
13:12
Speaker 1: represented as ones or zeros or you know, things you
13:15
Speaker 1: print on a piece of paper. But fundamentally, it's the
13:17
Speaker 1: arrangement of the particles. It's really it's the quantum wave
13:21
Speaker 1: function that tells you where the particles are or where
13:24
Speaker 1: they are likely to be, and how they are interacting.
13:27
Speaker 1: Remember that everything, me and you and bananas and all
13:31
Speaker 1: that stuff are made out of particles, and we're all
13:32
Speaker 1: made out of the same particles. So the thing that's
13:35
Speaker 1: different between you and lava and hamsters and bananas is
13:40
Speaker 1: not the stuff you're made out of. That's really the
13:42
Speaker 1: same stuff that everything is made out of. It's how
13:44
Speaker 1: that stuff is put together. It's like if you had
13:47
Speaker 1: a book of recipes and they all had exactly the
13:49
Speaker 1: same ingredients, just had different arrangements like where you put
13:52
Speaker 1: the stuff. That's literally how things in the universe are built.
13:56
Speaker 1: And so what we mean by information from a physics
13:58
Speaker 1: point of view is just that is how the particles
14:01
Speaker 1: are put together to make this versus that, right, And
14:03
Speaker 1: it's also kind of the history of them a little bit, right,
14:06
Speaker 1: Like you can make a banana cake and I can
14:08
Speaker 1: make a banana caig, but they're going to be different
14:10
Speaker 1: bana caggs depending on you know, what the size of
14:13
Speaker 1: the pan I use, or whether I put in a
14:16
Speaker 1: little bit more of this, or a little bit more
14:17
Speaker 1: of that, or how I poured it. They're bothing that
14:19
Speaker 1: tastes like banana aig, but they're gonna be different banana
14:21
Speaker 1: caigs because they were arranged kind of with a different history.
14:25
Speaker 1: And that's right. So our two banana cream pies both
14:27
Speaker 1: have information about what happened to those bananas, how they
14:30
Speaker 1: got there, how they originally were developed and grown and
14:34
Speaker 1: blended up and and turned into the banana cream pies.
14:37
Speaker 1: Because our two banana cream pies are not identical, they
14:40
Speaker 1: contain information about how they got there. Their arrangements are
14:44
Speaker 1: unique because only one way to create that particular banana
14:48
Speaker 1: cream pie. And so you could run the clock backwards
14:51
Speaker 1: and figure out where everything came from in your pie. Yeah,
14:54
Speaker 1: So I think that kind of what you're saying is
14:56
Speaker 1: that it's like, it's kind of like if you're playing
14:59
Speaker 1: billiards or some thing, if you see all the balls
15:01
Speaker 1: kind of arranged in a particular way on the table,
15:03
Speaker 1: you can sort of backtrack how they all got to
15:06
Speaker 1: how billiard balls usually start. That's right, And that's what
15:09
Speaker 1: we mean when we say quantum mechanics does not destroy information.
15:13
Speaker 1: It says that you can tell how you got to
15:16
Speaker 1: where you are. So, just like you said in the
15:18
Speaker 1: billiard balls example, if you see balls moving on the table,
15:23
Speaker 1: you can tell how you got there. You said, well,
15:25
Speaker 1: this must have happened in a certain way. You know,
15:27
Speaker 1: Bob must have hit Alice's ball and it bounced off
15:31
Speaker 1: this wall, etcetera, etcetera. There's only one way to get
15:33
Speaker 1: to this exact particular arrangement. And so because information is
15:37
Speaker 1: not destroyed, it's all the information you need to figure
15:41
Speaker 1: out how you got here is present in this configuration.
15:44
Speaker 1: You could run the clock backwards, you can run a
15:46
Speaker 1: physics simulation backwards and figure out exactly how you got
15:49
Speaker 1: to hear or run it forward. Right like that, I
15:52
Speaker 1: think you're saying that there's no ambiguity in the universe,
15:54
Speaker 1: Like if you you come upon a crime scene, you
15:57
Speaker 1: can tell exactly what happened, like a physicist could. If
16:00
Speaker 1: you sort of rewind the universe and play the laws
16:02
Speaker 1: of physics backwards, you can sort of reconstruct what happens
16:05
Speaker 1: every time precisely. And it's really weird that this comes
16:08
Speaker 1: up in quantum mechanics because you might think, yeah, quantum
16:10
Speaker 1: mechanics is not something that's going to give you certainty
16:13
Speaker 1: that tells you you can know everything about the universe, right,
16:16
Speaker 1: because quantum mechanics is something that feels like it has
16:18
Speaker 1: a lot of built in uncertainty. And so what quantum
16:22
Speaker 1: mechanics tells you is you can always know the wave function.
16:24
Speaker 1: That's the thing that tells you where the particles are
16:26
Speaker 1: likely to be, not that you could actually know where
16:29
Speaker 1: the particles are. In the same way, you can backtrack
16:32
Speaker 1: the wave function. You can say if the particles have
16:35
Speaker 1: a certain way function that says that they're more likely
16:37
Speaker 1: to be on the left side of the table. Now
16:39
Speaker 1: you can backtrack that and tell where they were likely
16:42
Speaker 1: to be in the past, not where they actually were.
16:44
Speaker 1: It's all about the wave function. It's all about this
16:47
Speaker 1: evolving probabilities. The way so looking back into the past
16:50
Speaker 1: is also there's also probabilities or do you know for
16:53
Speaker 1: sure where the party like if like if I see
16:56
Speaker 1: an electron and I measure, you know where it is
16:59
Speaker 1: and where it's going to the best degree that I
17:01
Speaker 1: can can, I tell you where it was before and
17:03
Speaker 1: how fast it was going. No, you can only know
17:05
Speaker 1: the probabilities. You can't collapse the wave function into the
17:08
Speaker 1: past because that would have changed where it is today.
17:12
Speaker 1: But if you know the way function today right, then
17:15
Speaker 1: you can backtrack it into the past and you can
17:17
Speaker 1: propagate it into the future. Any idea is that if
17:21
Speaker 1: you look at any configuration of matter, you should be
17:23
Speaker 1: able to tell where it came from. That's the core
17:26
Speaker 1: idea that you have to understand. I see. So when
17:28
Speaker 1: you talk about information, you don't mean like where things
17:31
Speaker 1: are and where they're going, but you also kind of
17:33
Speaker 1: include these quantum probabilities as information, Like that's also information
17:38
Speaker 1: to physics, Yes, that's the actual quantum information, because they
17:41
Speaker 1: don't know where the particles are. We really just know
17:44
Speaker 1: these probabilities. And so like when we talk about like
17:46
Speaker 1: quantum teleportation copying things, we're talking about copying not the
17:51
Speaker 1: where the particles actually are, but their probabilities, because that's
17:55
Speaker 1: really what the quantum information is. It kind of feels
17:57
Speaker 1: a little unsatisfying on physicists because I feel I feel
18:01
Speaker 1: like you're telling me that information includes not knowing kind
18:05
Speaker 1: of in a way, you know what I mean, Like
18:07
Speaker 1: information includes also non information. Yeah, what's the most information
18:11
Speaker 1: that you can have about the universe is information about
18:14
Speaker 1: the probabilities, and that information cannot be destroyed. Like we
18:18
Speaker 1: don't know where the electron is. It's not like there's
18:20
Speaker 1: a fact there that's not accessible to us. It just
18:22
Speaker 1: isn't determined. But the way function is the thing that
18:25
Speaker 1: tells you that it's more probable to find it on
18:28
Speaker 1: the left side or the right side. That is totally determined.
18:31
Speaker 1: And that's the level of quantum information we can have.
18:33
Speaker 1: That's the most information that the universe allows you to
18:37
Speaker 1: have almost right, Like you know you can know the
18:39
Speaker 1: position and the velocity of a particle to a perfect
18:43
Speaker 1: degree because of the uncertainty principle, because and that's just
18:46
Speaker 1: the rule of the universe. The universe is like, nope,
18:48
Speaker 1: you can't know everything all of the time everywhere. That's right,
18:52
Speaker 1: And that's why quantum information cannot be destroyed, because the
18:55
Speaker 1: probabilities cannot be destroyed. Like if an electron is somewhere
18:59
Speaker 1: in your box now, then it is somewhere in your
19:02
Speaker 1: box in the future. You're like, out of all the
19:04
Speaker 1: probabilities in the future, they still have to add up
19:06
Speaker 1: to one. And that's why if you run the clock backwards,
19:09
Speaker 1: you should still get probabilities adding up to one in
19:12
Speaker 1: the past, and if you run it back even further,
19:14
Speaker 1: you should still get probabilities added up to one because
19:17
Speaker 1: information is not destroyed can't just disappear, because your particles
19:20
Speaker 1: don't just disappear, you don't know where they are. But
19:23
Speaker 1: the probabilities can't disappear. The probabilities can slash around, but
19:27
Speaker 1: they can't just go away. And so that's why we're
19:30
Speaker 1: so fascinated about what happens inside a black hole, because
19:32
Speaker 1: we're wondering, like, does the information inside a black hole?
19:36
Speaker 1: Does it get deleted or is it still stored in there,
19:39
Speaker 1: Like it's a black hole that has a banana versus
19:41
Speaker 1: an apple, have something different inside it that tells you
19:44
Speaker 1: that one has a banana, one has an apple, or
19:47
Speaker 1: the actually deleting stuff. Interesting? Interesting, Yeah, I get. The
19:51
Speaker 1: question is if I throw a banana and one black hole,
19:56
Speaker 1: and I throw the equivalent apple the copy of that
19:59
Speaker 1: black hole, are the two black holes different at the
20:01
Speaker 1: end or are they basically the same? That's kind of
20:03
Speaker 1: the question exactly, And quantum mechanics says they have to
20:06
Speaker 1: be different because if they're not different, then you've destroyed
20:09
Speaker 1: the information about which one got the banana and which
20:11
Speaker 1: one got the apple in a corner. Quantum mechanics, and
20:14
Speaker 1: this is a very deep, very bedrock principle. Information cannot
20:18
Speaker 1: be destroyed. Like you go to a particle theorist and
20:21
Speaker 1: you say, what if I prove the quantum mechanics doesn't
20:24
Speaker 1: preserve information, that you can delete information from the universe,
20:26
Speaker 1: then basically they just throw all their books away and
20:29
Speaker 1: we have to start everything from scratch. It's that deeply
20:33
Speaker 1: ingrained into physics. I guess it's like comparing apple black
20:36
Speaker 1: holes to banana black holes. All Right, I'm starting to
20:40
Speaker 1: feel a bit a little bit like a dog here, uh,
20:42
Speaker 1: and not fully able to grasp all this stuff. But
20:45
Speaker 1: that's kind of the nature of quantum mechanics. So let's
20:48
Speaker 1: get into whether or not black holes can destroy this
20:51
Speaker 1: quantum information, and if they can, then how do we
20:54
Speaker 1: explain it? But first let's take a quick break. All right,
21:09
Speaker 1: we're talking about weather. Black holes can destroy quantum information.
21:14
Speaker 1: And so Danny, you were telling me that quantum information
21:17
Speaker 1: includes like the probability of all the particles in the universe,
21:21
Speaker 1: or at least a bunch of particles that you're looking at,
21:24
Speaker 1: and you're telling me that quantum mechanics says that you
21:26
Speaker 1: can't destroy this information, Like you can't just forget about it,
21:30
Speaker 1: Like it's always kind of encoded in how the particles
21:33
Speaker 1: are arranged or what they're doing. That's right. It's sort
21:35
Speaker 1: of like the central premise of that TV show Devs,
21:38
Speaker 1: where they try to reconstruct details about what happened two
21:41
Speaker 1: thousand years ago by getting really fine data about the
21:44
Speaker 1: molecules in the air and the earth and just backtracking
21:47
Speaker 1: it two thousands of years. The ideas that the evidence
21:50
Speaker 1: for the past is still with us here in the president,
21:53
Speaker 1: that if you had incredible computing power and enough data,
21:56
Speaker 1: you could reconstruct any event. It's like the perfect crime novel. Wow,
22:00
Speaker 1: and so yeah, Like can you look at a banana
22:03
Speaker 1: and tell what the plant the griod looked like? Kind of,
22:06
Speaker 1: that's right, the ideas that no two bananas are identical,
22:09
Speaker 1: but somewhere in that banana there's a clue about where
22:12
Speaker 1: it came from and what it was like and whether
22:14
Speaker 1: it got sun on a certain day, and all that
22:16
Speaker 1: information is somehow encoded in the banana. They're making me
22:20
Speaker 1: feel guilty about eating a banana. You're like you're destroying
22:23
Speaker 1: a perfect, unique gem in the univers just becomes part
22:26
Speaker 1: of who you are. Right, if I took you apart,
22:28
Speaker 1: I could figure out exactly how many bananas you had
22:31
Speaker 1: last week and what happened to them, and the stars
22:34
Speaker 1: that burn the potassium that's in that banana, Like all
22:37
Speaker 1: that history is encoded in that banana and then in you. Well,
22:41
Speaker 1: and also when I flushed down the toilet, technically you
22:43
Speaker 1: would have to go down the toilet. That's a whole
22:46
Speaker 1: different maybe podcast episode. That's a different kind of black hole.
22:49
Speaker 1: We're not going to dive into different um. So let's
22:52
Speaker 1: get into now. Quantum mechanics says that you can destroy
22:55
Speaker 1: quantum information. And so what happens when you throw it
22:58
Speaker 1: into a black hole? Like does it get destroyed or
23:01
Speaker 1: does it stay around inside of the black hole? That's
23:03
Speaker 1: the big question. Yeah, and so on the surface you imagine, well,
23:06
Speaker 1: black holes suck in information. Right, you put something into
23:10
Speaker 1: a black hole, it can never leave, So therefore it's
23:13
Speaker 1: information is stuck inside the black hole. That doesn't mean
23:16
Speaker 1: necessarily that it's destroyed. Right, Like you put a banana
23:18
Speaker 1: inside a black hole, you could still be in there.
23:21
Speaker 1: The particles that made it up could be like squished
23:23
Speaker 1: and whatever, but they just got quantum mechanics aified into
23:26
Speaker 1: a new arrangement. And just like when you ate the
23:29
Speaker 1: banana or when it grew, it's information could still be preserved,
23:32
Speaker 1: but be stuck inside the black hole, you know, like
23:35
Speaker 1: a like a neutron star kind of breaks everything down
23:39
Speaker 1: to the cork level, but all the courts are still
23:41
Speaker 1: kind they're bunched together precisely, and if the information is
23:43
Speaker 1: still in there, it's stuck inside the black hole. Right,
23:46
Speaker 1: nothing can ever leave the black hole. But also you
23:49
Speaker 1: can't get any information from the outside about what's in
23:52
Speaker 1: the black hole. The only things you can know about
23:55
Speaker 1: a black hole are its mass, whether it's spinning, and
23:59
Speaker 1: whether as electric charge. There's this crazy theorem in physics
24:03
Speaker 1: called the no hair theorem that says that's all you
24:06
Speaker 1: can know about a black hole. You mean, like the
24:08
Speaker 1: overall charge of it, Like the black hole can have
24:10
Speaker 1: a charge to it. Yeah, if you have a black
24:12
Speaker 1: hole with no charge, it's neutral, and you throw an
24:14
Speaker 1: electron into it, then it has a charge and you
24:17
Speaker 1: can measure that charge. You can know whether there are
24:20
Speaker 1: charged particles inside a black hole. Oh, I guess you
24:23
Speaker 1: can measure how much it pulls proton through or something
24:26
Speaker 1: like that, just like you can measure it's mass. You
24:28
Speaker 1: throw a banana into a black hole, it got heavier.
24:31
Speaker 1: You should be able to measure its mass by measuring
24:33
Speaker 1: the gravitational field around a black hole. Can also measure
24:36
Speaker 1: whether it's spinning. But that's the extent of the information
24:39
Speaker 1: you can have, right. You can't tell what's inside. You
24:43
Speaker 1: can't tell the detailed history of the banana from the outside,
24:45
Speaker 1: so you can never get that information back out, right.
24:49
Speaker 1: So that's step number one. Is the information, if it
24:51
Speaker 1: still exists, is inside the black hole and can never leave, right.
24:55
Speaker 1: But that's not the same as destroying it. It's just
24:57
Speaker 1: kind of storing it. It's like inside if somewhere I
24:59
Speaker 1: can never that's right. And if black holes live forever,
25:02
Speaker 1: this wouldn't really be an issue. Would be a question of, like, well,
25:05
Speaker 1: what happens inside the black hole? It's fascinating, but we
25:07
Speaker 1: believe that probably information is just in there, sort of
25:10
Speaker 1: cut off from us forever, but still existing. Right, it's
25:14
Speaker 1: still having its own little happy life inside of the
25:16
Speaker 1: black hole. That's right. The banana party, that's where bananas
25:19
Speaker 1: go so that you don't eat them. Right, it's the
25:21
Speaker 1: only safe space in the universe. They don't have to
25:24
Speaker 1: worry about training black because everything is black inside of
25:27
Speaker 1: a black hole. That's right. But then Stephen Hawking came
25:31
Speaker 1: along and he showed us that black holes actually they
25:34
Speaker 1: can disappear, right, Yes, you can make it black hole disappear.
25:38
Speaker 1: It can evaporate. Yeah, black holes they evaporate. They give
25:42
Speaker 1: off very small amounts of radiation, little particles here there.
25:46
Speaker 1: For very big black holes, this happens extremely slowly. But
25:50
Speaker 1: as black holes get smaller, they evaporate more quickly, and
25:54
Speaker 1: then they can actually disappear. They can poof out of
25:56
Speaker 1: existence as they give away their last little bit of energy.
26:00
Speaker 1: Even like giant black holes will eventually disappear, like once
26:04
Speaker 1: all black holes suck everything in the universe, Eventually they
26:07
Speaker 1: will evaporate. Right, that's right. A black hole, if you
26:09
Speaker 1: do not feed, it will give off Hawking radiation and
26:12
Speaker 1: get smaller. Right. It gives off its energy, and that
26:15
Speaker 1: energy comes from its mass, and so therefore it gets smaller,
26:18
Speaker 1: and the smaller it gets, the more radiates. So giant,
26:22
Speaker 1: massive black holes they might have lifetimes of trillions of years.
26:25
Speaker 1: But yes, eventually they will radiate away all of their
26:30
Speaker 1: mass in terms of this hawking radiation and disappear, right,
26:33
Speaker 1: And so then the question is what happened to the
26:36
Speaker 1: information you put into it? That's right, what happened to
26:39
Speaker 1: the information inside the black hole? Like you put this
26:41
Speaker 1: banana inside the black hole. You trust the black hole
26:44
Speaker 1: is going to keep your banana information safe. But then
26:46
Speaker 1: you come back a billion years later and the black
26:48
Speaker 1: holes gone. You're like, what what happened to my You
26:51
Speaker 1: deleted my banana from the universe. You know you can't
26:54
Speaker 1: do that. Quantum mechanics says that's impossible. So the question
26:58
Speaker 1: is what happened to the information? And you might be
27:01
Speaker 1: tempted to think, oh, well, maybe it's somehow stored in
27:03
Speaker 1: that hawking radiation, right, because the hawking radiation came out
27:07
Speaker 1: of the black hole. But hawking radiation is very special.
27:10
Speaker 1: It comes from the temperature of the black hole. It
27:13
Speaker 1: comes from treating a black hole, like everything else in
27:15
Speaker 1: the universe, is a thing that has a non zero
27:18
Speaker 1: temperature which glows. And what's very important to understand is
27:22
Speaker 1: that the hawking radiation depends only on the mass of
27:25
Speaker 1: the black hole. Like how much hawking radiation you get
27:28
Speaker 1: and which particles you get are determined by the mass
27:31
Speaker 1: of the black hole and literally zero else, So none
27:34
Speaker 1: of the information that's inside the black hole can possibly
27:38
Speaker 1: leak out in hawking radiation. Well, I guess it's kind
27:41
Speaker 1: of like if you have a glass of water, if
27:43
Speaker 1: you leave it out, it's gonna evaporate, but you can
27:46
Speaker 1: sort of trace what happened to the water. You can
27:49
Speaker 1: trace the like the vapor of what molly kills as
27:51
Speaker 1: it least the glass of water. Like that's okay, Like
27:54
Speaker 1: that's preserving the information. That's right. But a black hole
27:58
Speaker 1: doesn't evaporate by having the stuff inside of it leak out.
28:02
Speaker 1: It evaporates by almost like having the stuff at the
28:04
Speaker 1: surface destroyed itself. Kind of that's right. And remember the
28:07
Speaker 1: no hair theorem tells us that you can't get any
28:10
Speaker 1: information out of a black hole. That none of the
28:13
Speaker 1: configuration of particles inside a black hole, or the swirling
28:16
Speaker 1: or non swirling, or the singularity or non singularity can
28:19
Speaker 1: affect what's produced on the outside of the black hole.
28:22
Speaker 1: So the Hawking relation cannot have any information about what's
28:26
Speaker 1: going on inside the black hole. It's not like that
28:28
Speaker 1: water vapor example. It's a good contrast because it doesn't
28:32
Speaker 1: tell you anything about what happened inside the black holes.
28:34
Speaker 1: This amazing sort of mysterious way to delete a black
28:38
Speaker 1: hole without knowing anything about what's inside of it, right,
28:40
Speaker 1: because the reason is not because of the theorem. The
28:42
Speaker 1: theorem is sort of because of what's happening in the
28:45
Speaker 1: physics of it, right, And it's yeah, the theorem describes
28:48
Speaker 1: the physics of it right, right, And and what's happening
28:51
Speaker 1: is that, like at the surface of a black hole,
28:53
Speaker 1: you get this pair of particle and antiparticles kind of appearing,
28:57
Speaker 1: and one of them goes into the black hole, the
28:58
Speaker 1: other one goes out of the black hole, and that's
29:02
Speaker 1: kind of how it evaporates. Happening at the surface of it.
29:04
Speaker 1: It's not happening because of anything that's inside of the
29:07
Speaker 1: black hole exactly, and it comes just from the mass
29:09
Speaker 1: the black hole. As you say, virtual particles like positron
29:13
Speaker 1: anti positron pairs are created near the black hole's edge
29:17
Speaker 1: where there's a lot of gravitational energy, and then one
29:21
Speaker 1: of them is given a boost from that gravitational energy
29:24
Speaker 1: while the other one maybe gets sucked in, and because
29:26
Speaker 1: it's given a boost from that gravitational energy, that energy
29:29
Speaker 1: comes from the mass of the black holes. The black
29:32
Speaker 1: hole itself is decreased a tiny little bit in mass,
29:36
Speaker 1: and so it's stealing some of the energy from the
29:39
Speaker 1: black hole without apparently taking any information from it. And
29:43
Speaker 1: so that's the weird thing is that, like you put
29:46
Speaker 1: information in a black hole, you can never get it out,
29:49
Speaker 1: but then the black hole can disappear. So where did
29:52
Speaker 1: the information go? Really, there's no information in that suckings radiation.
29:56
Speaker 1: I mean, like, wouldn't it like where it happens where
30:00
Speaker 1: there's these particles and antiparticles form and where the one
30:03
Speaker 1: of them goes right and the other one goes left.
30:04
Speaker 1: Wouldn't that sort of depend on exactly what's going on
30:09
Speaker 1: inside of the black hole. Well, the where the particles
30:11
Speaker 1: are created is just quantum randomness around the black hole,
30:15
Speaker 1: so that happens totally randomly, not depending on what's inside
30:18
Speaker 1: the black hole. And then they're boosted from the gravitational field,
30:22
Speaker 1: which is the mass of the black hole. So you
30:24
Speaker 1: can know the mass of the black hole, and that's
30:26
Speaker 1: what determines how these particles get boosted and whether they
30:30
Speaker 1: go in the right direction, etcetera. But that doesn't contain
30:32
Speaker 1: all the information. Like if you threw an apple or
30:35
Speaker 1: an equivalently masked banana into a black hole, that would
30:38
Speaker 1: give you black holes of the same mass, so they
30:40
Speaker 1: would affect talking radiation in exactly the same way. So
30:43
Speaker 1: the fact that one used to be an apple and
30:45
Speaker 1: one used to be a banana is now irrelevant, which
30:47
Speaker 1: means quantum information has been deleted all right, which is
30:52
Speaker 1: kind of bad news for quantum physics, because you're telling
30:55
Speaker 1: me that this idea that you can't destroy information is
30:59
Speaker 1: fund mental to quantum mechanics. Maybe I really quickly, can
31:03
Speaker 1: you tell me why it's so fundamental. I mean, remember
31:05
Speaker 1: what we talked about earlier. The reason you can't destroy
31:08
Speaker 1: information in quantum mechanics is because particles should always exist somewhere.
31:13
Speaker 1: I mean, if you have a particle now, as you
31:15
Speaker 1: exist somewhere in the future, it's quantum information cannot be destroyed,
31:19
Speaker 1: like you don't know exactly where it is, but you
31:22
Speaker 1: know what it's probability distribution looks like, and it should
31:25
Speaker 1: have a probability distribution in the future also, and so
31:30
Speaker 1: that can change as the universe moves forward, but the
31:33
Speaker 1: information about should not be deleted anywhere. Right, Well, I
31:36
Speaker 1: guess my question is, you know why not? Like why why?
31:40
Speaker 1: Why would we quantum mechanics breakdown if I just suddenly
31:44
Speaker 1: took some particles and deleted their quantum information? Like why
31:48
Speaker 1: would the universe complain or with the universe care if
31:51
Speaker 1: I had destroyed that information? All? Right? Well, mathematically we
31:54
Speaker 1: look at the equations that describe a wave functions. We
31:57
Speaker 1: have a wave function that tells us where particles are
31:59
Speaker 1: likely to be you, and that moves forward in time.
32:02
Speaker 1: There's an equation that describes how that happens. It's called
32:04
Speaker 1: the shrouding your equation, and the shrouding your equation says
32:08
Speaker 1: you can move information from here to there, but it's unitary,
32:11
Speaker 1: doesn't ever destroy information. And if information is destroyed, that
32:16
Speaker 1: means that wave functions can disappear. And that just doesn't
32:19
Speaker 1: happen in the shorten your equation, and so we would
32:22
Speaker 1: have to totally rethink the way quantum mechanics works if
32:25
Speaker 1: that was to happen. It's like a bedrock assumption that
32:27
Speaker 1: we've built into quantum mechanics. I see, it's like I
32:31
Speaker 1: guess in quantum mechanics and wave functions, you know, these
32:35
Speaker 1: functions don't don't just exist in the present and in
32:37
Speaker 1: the past. They're all sort of tied together mathematically to
32:41
Speaker 1: where they're going to be in the future. That's right,
32:43
Speaker 1: So like if you destroy it in the future, then
32:45
Speaker 1: you're really destroying it through all history. You don't have
32:47
Speaker 1: a term for that in the equation. Yeah, And the
32:50
Speaker 1: equations work the same way forwards and backwards in time,
32:53
Speaker 1: and so if the wave function is ever destroyed, that
32:56
Speaker 1: means that you couldn't go from a non existent wave
32:58
Speaker 1: function backwards in time into the wave function you have now.
33:02
Speaker 1: So this sort of this time and variance built into
33:04
Speaker 1: quantum mechanics. You can run the clock forward, you can
33:06
Speaker 1: run the clock backwards. You should be able to move
33:09
Speaker 1: backwards and forwards at all points. But if the information
33:11
Speaker 1: is ever deleted, that means you can't move backwards and
33:14
Speaker 1: forwards at all points. And the shrunning equation, the basic
33:16
Speaker 1: assumptions on which it's built are totally wrong, and quantum
33:20
Speaker 1: mechanics doesn't work, and we'd have to come up with
33:22
Speaker 1: a new theory. It's not like the universe would puff
33:24
Speaker 1: out of existence. Right, This is all human ideas about
33:28
Speaker 1: how the universe might work. This is a basic assumption
33:31
Speaker 1: we've built into quantum mechanics that we're pretty sure is right.
33:35
Speaker 1: But black holes are telling us that they're doing something
33:38
Speaker 1: that we thought was impossible. Man, there's such troublemakers, all right,
33:43
Speaker 1: So we have a big unknown here. How can both
33:45
Speaker 1: things be true? How could information never be destroyed according
33:50
Speaker 1: to quantum mechanics and how can information be destroyed according
33:54
Speaker 1: to black holes and hawking radiation? So let's get into
33:57
Speaker 1: what could possibly explain this can prediction. But first let's
34:01
Speaker 1: take a quick break, all right, Daniel, can information be
34:14
Speaker 1: destroyed inside of a black hole? So quantum mechanics says no,
34:18
Speaker 1: but kind of a black hole say yes. So what's
34:22
Speaker 1: going on? Is quantum mechanics wrong or do black holes
34:26
Speaker 1: just kind of destroy our conception of how the universe works.
34:30
Speaker 1: This is a big puzzle in physics for a long time,
34:33
Speaker 1: and it's such a big puzzle that like big folks
34:36
Speaker 1: on both sides, like great brains on both sides of
34:38
Speaker 1: the argument, had like public debates about it and even
34:41
Speaker 1: made bets about the resolution of this. Right. Yeah, there's
34:44
Speaker 1: a famous bed by between Hawking and Kip Thorne and
34:48
Speaker 1: John Preskill. Right, that's right. John Prescille believed that somehow
34:51
Speaker 1: the information was sneaking out of the black hole back
34:54
Speaker 1: into the universe, that it was leaking out essentially where
34:57
Speaker 1: Stephen Hawking and Kip Thorn they thought, know, the information
35:01
Speaker 1: can't ever leave the black hole, and therefore it must
35:03
Speaker 1: be lost from the universe, and quantum mechanics is wrong.
35:06
Speaker 1: So they made a very public sort of bet about this.
35:08
Speaker 1: All right, So they made this bed and did they
35:12
Speaker 1: was one of im proven right? Well, they did come
35:14
Speaker 1: to what they think is a resolution to this, and
35:17
Speaker 1: so Hawking and Thorn actually capitulated on the bet in
35:20
Speaker 1: public and said, all right, Prescott, we think you're right.
35:23
Speaker 1: We think that the information somehow leaks out of the
35:26
Speaker 1: black hole. So wait, physicists think that black holes don't
35:30
Speaker 1: destroy information. That's right. So the idea now is probably
35:33
Speaker 1: black holes don't destroy information. I mean, the general categories
35:36
Speaker 1: of solutions are one, maybe quantum mechanics is just wrong
35:40
Speaker 1: and we have to toss it all out and rethink
35:43
Speaker 1: everything about our idea of the universe at the smallest scales,
35:47
Speaker 1: like that's an option and hey, that wouldn't be so bad.
35:49
Speaker 1: It's not like everything unravels and we all go living
35:53
Speaker 1: in caves or something. Just a bunch of physicist careers unraveled. No,
35:57
Speaker 1: those are the best moments for physicist careers because like, wow,
36:00
Speaker 1: that cracks open something deep that we thought was true.
36:03
Speaker 1: Those are the revolutions in physics we live for. That's
36:06
Speaker 1: why we're here to figure out what in the firm
36:09
Speaker 1: and turns out to be wrong, because those are the
36:11
Speaker 1: times when you can get a new glimpse onto a
36:13
Speaker 1: new insight into the universe. I mean, wow, that would
36:16
Speaker 1: be amazing. Right, So that's one possibility maybe quantum mechanics
36:19
Speaker 1: is wrong um, And what are other possibilities black holes
36:23
Speaker 1: are wrong? Another one is that like black holes, you
36:27
Speaker 1: can think of them as storing this information, but that
36:30
Speaker 1: they're also like connected to another universe. We've talked about
36:33
Speaker 1: how maybe black holes are like doors to wormholes that
36:38
Speaker 1: are connected on the other side to other places in
36:40
Speaker 1: the universe. They could also be connected to like separate
36:44
Speaker 1: distinct universes that we don't otherwise have access to. It's
36:48
Speaker 1: a possibility. I mean, we're it's like a what if
36:50
Speaker 1: on top of a wood if. But the idea is
36:52
Speaker 1: that therefore the information could be in that universe, like
36:56
Speaker 1: maybe the banana got sucked into the black hole and
36:59
Speaker 1: then slur belong to the wormhole and it's living off
37:02
Speaker 1: it's banana like days in that other universe. Now, even
37:05
Speaker 1: when our black hole disappears, I see like somehow there's
37:09
Speaker 1: a white hole on the other side that's spewing out bananas.
37:13
Speaker 1: That's right, a banana hole. I think it's what the
37:15
Speaker 1: people in that universe we call it like that. I
37:19
Speaker 1: think they call it the magic banana fountain. They're like
37:22
Speaker 1: whole cult surrounding it about how generous this banana fountain is.
37:26
Speaker 1: You're like a god in that universe. You're like the
37:28
Speaker 1: giver of bananas in that universe. I'm a legend. I'm
37:32
Speaker 1: a legend in another universe. They're like, but please stop
37:35
Speaker 1: throwing bananas in there with a bite taken out already,
37:37
Speaker 1: I mean please. So that's one idea, Yes, that it's
37:41
Speaker 1: information is not disappearing, it's just going somewhere else. Yeah,
37:45
Speaker 1: but that's hard to really understand because then you can't
37:48
Speaker 1: still really do quantum mechanics, like the information is effectively
37:51
Speaker 1: lost to us, and so then we can't do quantum
37:54
Speaker 1: mechanics of our universe, so it's not really Essentially, if
37:58
Speaker 1: it's lost to us, it's a bummer. It's a bummer
38:00
Speaker 1: because you know, is our wave function entangled with their
38:03
Speaker 1: wave function if they're in another universe? Then no, And
38:06
Speaker 1: so really quantum mechanics says, you can't lose any information
38:09
Speaker 1: from your wave functions. So if you lose it to
38:11
Speaker 1: a totally incoherent wave function, it's effectively lost anyway. So
38:17
Speaker 1: quantum mechanics says no to that. Very clever, I think,
38:20
Speaker 1: awesome idea, which would be a great basis for science fiction.
38:23
Speaker 1: Interesting like we're entangled with other universe. Yeah, but we
38:26
Speaker 1: wouldn't actually be entangled, right, That's the problem is that
38:29
Speaker 1: our wave function isn't connected to theirs because it goes
38:31
Speaker 1: through the wormhole. All right, So then what's the third
38:35
Speaker 1: The third possibility is that maybe somehow that information is
38:39
Speaker 1: actually imprinted on the Hawking radiation. So go back, that's
38:42
Speaker 1: what I was saying, wasn't it that you were saying?
38:45
Speaker 1: He shot me down? But now it seems like Stephen
38:48
Speaker 1: Hawking agrees with me. That's right. This is known as
38:51
Speaker 1: the Hawking thorn cham theory of the universe should be. No,
38:57
Speaker 1: you're right, and you know, our understanding before this was
39:01
Speaker 1: that it's impossible for the information to be in the
39:03
Speaker 1: Hawking radiation for the very reasonable arguments that I gave
39:06
Speaker 1: you five minutes ago, which I will now undermine. It
39:12
Speaker 1: made me feel bad, Daniel, No, nor yeah, alright, So
39:16
Speaker 1: here's why your idea was a good one. And you know,
39:18
Speaker 1: whenever you have an apparent contradiction, you have a string
39:21
Speaker 1: of logical arguments that leads you to something nonsensical, you
39:23
Speaker 1: have to go back and read examined, like well what
39:25
Speaker 1: about this one? Is this one? Are we really sure
39:27
Speaker 1: about this? And try to find a hole in it.
39:30
Speaker 1: And so the idea is that maybe somehow the information
39:33
Speaker 1: about the banana you threw in is imprinted on the
39:36
Speaker 1: hawking radiation. Well, how could that happen because once it
39:39
Speaker 1: goes inside the black hole, the only information we can
39:42
Speaker 1: get about it is how much mass it has, which
39:44
Speaker 1: is essentially destroying the banana nous of the information. So
39:49
Speaker 1: the idea is maybe it never really goes inside the
39:52
Speaker 1: black hole, like maybe a banana when you throw it
39:56
Speaker 1: into a black hole, spends eternity sort of on the
39:59
Speaker 1: surface of the black hole. One. And this is actually
40:03
Speaker 1: what what happens when you throw something into a black hole.
40:06
Speaker 1: You never actually see it go in because remember, when
40:10
Speaker 1: near a black hole, there's incredible gravity, and that slows
40:14
Speaker 1: down time. Like you threw a clock into a black
40:18
Speaker 1: hole and you watched it with a telescope, please from
40:20
Speaker 1: very far away, you would see that clock ticks slow
40:24
Speaker 1: down because the presence of mass slows downtime. Right. Yeah,
40:28
Speaker 1: So to the banana, you're seeing, the banana gets frozen
40:31
Speaker 1: at the surface kind of. Yeah. As it gets closer
40:34
Speaker 1: and closer to this event horizon, time slows down more
40:37
Speaker 1: and more, to the point where it slows down essentially infinitely.
40:41
Speaker 1: And you can watch this banana for the whole time,
40:44
Speaker 1: the lifetime of the universe. You will never see it
40:46
Speaker 1: cross the event horizon. Oh uh. It's not like it
40:50
Speaker 1: goes in and then the particles the photons can come out.
40:54
Speaker 1: It's like it never goes in. Kind of from our
40:56
Speaker 1: point of view, From our perspective, you never see anything
41:00
Speaker 1: actually go into a black hole. Now it gets closer
41:04
Speaker 1: and closer, and it gets redder and redder because the
41:07
Speaker 1: light from that banana, which can still get to you.
41:10
Speaker 1: Because the banana is not actually in the black hole,
41:12
Speaker 1: it gets stretched also by the gravity and gets redder
41:16
Speaker 1: and redd or longer and longer wavelengths. So what happens
41:18
Speaker 1: if you have trillions of years to hang out and watch,
41:21
Speaker 1: is that banana falls in more and more slowly, gets
41:24
Speaker 1: darker and darker, and eventually goes out past the visible spectrum.
41:27
Speaker 1: You can't see it, and then you have to use
41:28
Speaker 1: your infrared telescope to watch your very gently glowing banana. Right.
41:33
Speaker 1: But I guess I thought I thought time was became
41:37
Speaker 1: a singularity, only only at the center of the black hole.
41:39
Speaker 1: You're saying that time actually stops at the edge of it. Yeah,
41:43
Speaker 1: at the edge of the black hole, time slows down
41:45
Speaker 1: essentially infinitely, like and that's for you. You're from the
41:49
Speaker 1: outside point of view. You're watching the banana go in.
41:52
Speaker 1: That's not the same thing as the banana experiences. Banana
41:55
Speaker 1: can fall into a black hole, and it can totally
41:57
Speaker 1: experience going past the event horizon, right, because time always
42:00
Speaker 1: goes at one second per second for the person experiencing it.
42:04
Speaker 1: We have a different story about what happens in banana
42:07
Speaker 1: watching from the outside. So for us, the banana never
42:10
Speaker 1: actually goes into the black hole for us. Interesting for us. Wait,
42:15
Speaker 1: so it gets frozen at the surface forever. Yes, but
42:20
Speaker 1: it gets stretched out right, It's not like just happy,
42:23
Speaker 1: you can't go back and pick up your banana. It
42:24
Speaker 1: gets stretched out and reddened and smeared over the surface
42:28
Speaker 1: of the black hole. And essentially it distorts the event horizon.
42:32
Speaker 1: It like changes the shape of the event horizon in
42:35
Speaker 1: some way. And the ideas that maybe the banana changes
42:39
Speaker 1: the shape of the event horizon differently than an apple wood,
42:42
Speaker 1: or differently than another banana in a way that we
42:46
Speaker 1: can see, or in a way that we will never see,
42:48
Speaker 1: in a way that in principle preserves the quantum information
42:52
Speaker 1: of that banana and can influence the hawking radiation produced
42:57
Speaker 1: at that point instead of the event rise and being
43:00
Speaker 1: a perfectly smooth sphere and now has little quantum wiggles
43:04
Speaker 1: in it, and those quantum wiggles tell you about what's
43:08
Speaker 1: been thrown into the black hole, meaning that you could
43:11
Speaker 1: measure the hawking radiation and reconstruct whether you threw a
43:14
Speaker 1: banana or an apple in exactly that the black hole.
43:16
Speaker 1: You threw banana in would give you different hawking radiation
43:19
Speaker 1: than the banana you threw an apple into, and that
43:22
Speaker 1: it's encoded somehow and now in the surface of this
43:25
Speaker 1: black hole, which contains all the information but everything that's
43:29
Speaker 1: been thrown into the black hole. So you're not breaking
43:31
Speaker 1: general relativity because you're not getting information but what's inside
43:35
Speaker 1: the black hole, because in principle, all of this is
43:37
Speaker 1: now encoded on the surface of the black hole. Right,
43:40
Speaker 1: But the courts in the banana dude disappear or you
43:45
Speaker 1: don't see them. You don't see them going into the
43:47
Speaker 1: black hole. Like they're going to survive crazy experiences being
43:51
Speaker 1: near a black hole and get torn apart and smash
43:53
Speaker 1: and other stuff. So who knows what's going to happen,
43:55
Speaker 1: But their quantum information should still be there. Everything that
43:59
Speaker 1: happened to them is describable by quantum mechanics, and just
44:02
Speaker 1: like being eaten or being turned into banana smoothie, their
44:05
Speaker 1: history is still carried with me. And that's okay with
44:08
Speaker 1: quantum mechanics, Like as long as the quantum history information
44:12
Speaker 1: and information is somehow carried on, even if it's like
44:15
Speaker 1: passed between the banana cork it passes on that information
44:19
Speaker 1: to the hawking radiation. That's still okay, that's right. Did
44:21
Speaker 1: you just create a new kind of cork, the banana cork.
44:24
Speaker 1: We've got up cork, charm cork, banana cork. I thought
44:27
Speaker 1: they already existed. No, but you're exactly right. Somehow, the
44:31
Speaker 1: information about that cork that was inside your banana is
44:34
Speaker 1: encoded on the surface of the black hole and influences
44:37
Speaker 1: the hawking radiation that's produced. And therefore, if you like
44:41
Speaker 1: gathered all the hawking radiation that came out of a
44:44
Speaker 1: black hole, you could tell exactly what had gone into
44:47
Speaker 1: the black hole in the whole lifetime of the black hole.
44:50
Speaker 1: And this is weird because this is what they call
44:53
Speaker 1: like the holographic principle, meaning like you know, you can describe,
44:58
Speaker 1: like if the whole universe falls into a black hole,
45:00
Speaker 1: you could at some point technically everything would be described
45:03
Speaker 1: on the surface of the black hole, right, which is
45:05
Speaker 1: like a two D surface. It's like a flat surface. Yeah,
45:09
Speaker 1: it's sort of mysterious to say you can describe everything
45:12
Speaker 1: that's happening in a three D space, like the inside
45:15
Speaker 1: of a black hole, just by knowing information on a
45:18
Speaker 1: two D space the surface of the black hole. So like,
45:22
Speaker 1: how can everything inside a three D space be described
45:25
Speaker 1: by the surface of that space. Well, that's what we
45:28
Speaker 1: call a hologram. A hologram is a two D image
45:31
Speaker 1: that's projected into a three D space, so it looks
45:33
Speaker 1: three D. The entire hologram is determined actually by what's
45:37
Speaker 1: happening on the surface. So the ideas maybe black holes,
45:40
Speaker 1: the interiors of them are just holograms of their surfaces
45:44
Speaker 1: that you can build a sort of a theory of
45:47
Speaker 1: physics that works in three D. That's actually the theory
45:50
Speaker 1: of physics in two D on a surface, like you
45:53
Speaker 1: don't need three dimensions. Maybe you can describe everything on
45:56
Speaker 1: on a surface exactly. And so the idea is like, well,
45:58
Speaker 1: maybe that's also true like for our universe, Like maybe
46:02
Speaker 1: our three D universe is just a projection, is a
46:06
Speaker 1: two D hologram of what's happening at the edge of
46:09
Speaker 1: our universe. We think we live in this three D
46:13
Speaker 1: world and we're all moving around three dimensions. But if
46:16
Speaker 1: you can print all the information of a three D
46:19
Speaker 1: world onto a two D surface, then it's possible that
46:22
Speaker 1: we actually live on the two D surface at the
46:25
Speaker 1: edge of the universe somewhere and that what we experience
46:28
Speaker 1: is that three D world is really just a two
46:30
Speaker 1: D surface. But okay, so I guess it's like if
46:36
Speaker 1: this can happen on a black hole, then maybe it's
46:38
Speaker 1: happening everywhere. And maybe if we don't really need three dimensions,
46:41
Speaker 1: maybe like we have a redundant dimensions, right, And then
46:45
Speaker 1: there was this incredible result in string theory which backed
46:48
Speaker 1: this up. This guy at the Institute for Advanced Science,
46:51
Speaker 1: Jue Malda Sena, he came up with this theory that
46:54
Speaker 1: showed that string theory in you know, three dimensions that
46:58
Speaker 1: we experience, it can actually be described by a quantum
47:02
Speaker 1: theory in two dimensions. So he showed how you could
47:05
Speaker 1: reconstruct a theory of our universe in three dimensions only
47:09
Speaker 1: on a two dimensional surface. So it sort of showed
47:12
Speaker 1: mathematically that this might be possible. So what does that mean?
47:16
Speaker 1: That means that we're really living an illusion, like the
47:18
Speaker 1: three dimensions that we think we're living in are actually
47:21
Speaker 1: just an illusion. Kind of It could be, right, Yeah,
47:25
Speaker 1: it certainly could be. It could be that we actually
47:27
Speaker 1: live in a two D space Like I mean, it
47:28
Speaker 1: doesn't make any difference like feeling like you live in
47:31
Speaker 1: three D and actually living in three D, Like what's
47:33
Speaker 1: the difference? Uh? Nothing, But mathematically it might be that
47:38
Speaker 1: our three D universe can be described as just a
47:41
Speaker 1: two D surface, which is sort of fascinating because you
47:43
Speaker 1: feel like there's too much information here, right that that
47:47
Speaker 1: everything that's happening to us is somehow too much to
47:50
Speaker 1: squeeze down to two dimensions. But mathematically it can be equivalent.
47:54
Speaker 1: It could be that it's just that we don't have
47:56
Speaker 1: the full freedom of the three dimensions, that we're just
47:58
Speaker 1: a projection of two D spit. But I guess maybe
48:01
Speaker 1: the way you explain it maybe is that you also
48:03
Speaker 1: have time and maybe like somehow time is also giving
48:07
Speaker 1: you that extra feeling of a three or third dimension. Right, Well,
48:10
Speaker 1: here we're just talking about spatial dimensions, and so that
48:12
Speaker 1: two D space would also have time in it, so
48:15
Speaker 1: it's allowed to evolve that things can move on the
48:18
Speaker 1: two D surface, and that changes what happens inside the
48:21
Speaker 1: three D space, But we don't know right that. Yeah,
48:23
Speaker 1: I guess that's what I mean. It's like, because you
48:25
Speaker 1: have time, then you can maybe store more things into
48:27
Speaker 1: that to the information than then you might think. But
48:30
Speaker 1: you know, it's a big leap, Like we say, maybe
48:34
Speaker 1: information is stored on the surface of black holes, which
48:36
Speaker 1: means that maybe you can determine their interior to maybe
48:39
Speaker 1: the whole universe is a holomeram. Like, there's a lot
48:42
Speaker 1: of big leaps there, But again they're also fascinating there, Like,
48:45
Speaker 1: you know, maybe trying to solve this mystery about what's
48:48
Speaker 1: happening inside of a black hole tells us about what's
48:50
Speaker 1: possible for ideas we could have about the universe, and
48:54
Speaker 1: and reveals to us sort of shocking new mathematical connections
48:57
Speaker 1: that show us that the richness of our universe might
49:00
Speaker 1: actually be representable in terms of a smaller set of dimensions. Right, Yeah,
49:05
Speaker 1: like maybe we're all living in a video game. Kind
49:07
Speaker 1: of it just seems like we're in a three D world,
49:09
Speaker 1: but really we're we're just in this kind of reconstruction
49:13
Speaker 1: of a three D world, that's right. And if we
49:15
Speaker 1: are living in a video game, I want to know
49:16
Speaker 1: what are the cheat codes? How do I reset? How
49:20
Speaker 1: do I get extra lives? Exactly? All right? Well, um,
49:26
Speaker 1: it sounds like maybe black holes are not destroying information.
49:31
Speaker 1: Maybe that that seems to be kind of the current
49:33
Speaker 1: physics thinking is that maybe it is sort of recorded
49:36
Speaker 1: on the surfaces of black holes. Yeah, and you know,
49:38
Speaker 1: this stuff is pretty hand wavy. It's not like people
49:41
Speaker 1: have really worked out the mathematical details of it. It's
49:43
Speaker 1: sort of like an idea for idea we might have.
49:46
Speaker 1: It's like a crack a way to explore it that
49:49
Speaker 1: might be able to reveal what's happening with black holes
49:53
Speaker 1: and information. It's not like a very totally solid worked
49:55
Speaker 1: out idea. I see, these are just kind of like
49:58
Speaker 1: directions in which that might have playing these things exactly exactly,
50:02
Speaker 1: and we we we might be getting closer to knowing
50:05
Speaker 1: the answer, right, I mean, we just took a picture
50:06
Speaker 1: of a black hole. Maybe in the future we might
50:09
Speaker 1: get closer to it and figure these things out. Or
50:12
Speaker 1: is this closed off to us forever. That's a great question.
50:14
Speaker 1: And you know, we could send somebody into a black
50:17
Speaker 1: hole and maybe they could learn something about it. The
50:19
Speaker 1: problem is we'd never know the answer because they couldn't
50:22
Speaker 1: tell us. We might as well send dogs in, right, Well,
50:25
Speaker 1: we're going to get a letter from the cat. Our
50:28
Speaker 1: cats depending it. You know, Well, if you're a dog lover,
50:31
Speaker 1: you can, we can send cats to we should just
50:33
Speaker 1: send robots. And let's just send robots. No, there's no
50:36
Speaker 1: society protecting the life of robots, right, that's right, the
50:39
Speaker 1: dog robots, dog robots. There, that's a perfect compromise, all right.
50:43
Speaker 1: But again, it just tells you that there's a lot
50:45
Speaker 1: we don't know about the universe, and that even like
50:47
Speaker 1: our experience of it, this three dimensional experience of it,
50:50
Speaker 1: might be not real or not what we think it is. Yeah,
50:54
Speaker 1: and that deep insights into the very nature of the
50:57
Speaker 1: universe can come from these little odds and ends, these
50:59
Speaker 1: things that all we thought we understood, and then there's
51:02
Speaker 1: a little detail that doesn't quite make sense, and when
51:04
Speaker 1: you tug on that thread, it could unravel literally everything
51:08
Speaker 1: we think we understand about the universe. This is how
51:11
Speaker 1: lots of great discoveries were made relativity, quantum mechanics, and
51:15
Speaker 1: hopefully future crazy bonkers discoveries that people will have a
51:19
Speaker 1: hard time accepting is the true nature of the anivers
51:22
Speaker 1: Until then, I guess I'll stay to a blender to
51:24
Speaker 1: make my fans. I think that's a good idea. All right, Well,
51:28
Speaker 1: we hope you enjoyed that Thanks for joining us. Let's
51:31
Speaker 1: see you next time. Thanks for listening, and remember that
51:42
Speaker 1: Daniel and Jorge Explain the Universe is a production of
51:44
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