WEBVTT - Do black holes destroy information? 0:00:08.520 --> 0:00:11.320 Hey, Daniel, I've got a black hole question for you. 0:00:11.400 --> 0:00:13.680 Are you still hoping to catch and raise a black 0:00:13.680 --> 0:00:16.080 hole as a pet in your backyard? I can't confirm 0:00:16.200 --> 0:00:19.239 or deny that, But my question is what happens to 0:00:19.239 --> 0:00:21.720 the stuff I put into the black hole? Is this 0:00:21.760 --> 0:00:24.079 a question you already asked the folks at pet Smart. Yeah. 0:00:24.079 --> 0:00:26.160 You know, like, say, if I drop a banana into 0:00:26.239 --> 0:00:28.920 a black hole, what what happens to it? Is it 0:00:29.160 --> 0:00:32.480 gone forever? My advice is don't do it? Which part 0:00:32.600 --> 0:00:35.360 raise a black hole or throw a banana into it? 0:00:36.040 --> 0:00:39.000 Because I may have done both already. What's the difference? 0:00:39.000 --> 0:00:41.520 I mean, if you feed a black hole, it will grow, 0:00:42.040 --> 0:00:44.280 and a growing black hole will eat more, and eventually 0:00:44.600 --> 0:00:46.960 it will eat your house and then mine. Okay, so 0:00:47.120 --> 0:00:49.159 it's not a good idea to use a black hole 0:00:49.240 --> 0:01:09.039 to make banana's booties. Officially, no, not a good idea. Hi, 0:01:09.080 --> 0:01:11.080 I'm poor. Hey, I'm a cartoonist and the creator of 0:01:11.160 --> 0:01:14.720 PhD comics. Hi, I'm Daniel. I'm a particle physicist, and 0:01:14.760 --> 0:01:17.679 I have never created a black hole to my knowledge. 0:01:17.959 --> 0:01:19.880 How do you know, Daniel? Maybe you do it in 0:01:19.880 --> 0:01:22.360 your sleep by accident. Hey, I can't be responsible for 0:01:22.400 --> 0:01:26.000 all incidental black holes I accidentally create, right, I mean, 0:01:26.040 --> 0:01:28.000 there's got to be some legal principle there. Do you 0:01:28.000 --> 0:01:30.400 ever take homes any work by accident, you know, like 0:01:30.640 --> 0:01:33.320 you guys suddenly bring home some particles or some black 0:01:33.360 --> 0:01:35.840 holes that were created at the LHC. Yeah, sometimes I 0:01:35.880 --> 0:01:37.920 go home with a few extra protons in my pocket. 0:01:38.240 --> 0:01:42.600 Nobody even notices that doesn't sound good. But welcome to 0:01:42.600 --> 0:01:45.720 our podcast, Daniel and Jorge Explain the Universe, a production 0:01:45.880 --> 0:01:48.000 of I Heart Radio, in which we tell you all 0:01:48.040 --> 0:01:52.360 about the mysteries of the university, incredible cosmic questions that 0:01:52.600 --> 0:01:56.320 still make scientists puzzled, the things that we all wonder 0:01:56.360 --> 0:01:59.560 about this incredible, beautiful universe that we live in that 0:01:59.600 --> 0:02:02.960 we all desperately like to understand. Yeah. I take home 0:02:03.120 --> 0:02:05.880 work all the time, Daniel, because I work from home 0:02:06.040 --> 0:02:08.280 my cartoonist. So I think you take your home to 0:02:08.360 --> 0:02:12.520 work then, don't you You know the tomato tomato, it's 0:02:12.520 --> 0:02:14.840 all the same thing. But that's right. This is our 0:02:14.880 --> 0:02:18.760 podcast about the universe and all the amazing and mysterious 0:02:18.800 --> 0:02:21.639 things that are out there for us to discover. That's right, 0:02:21.680 --> 0:02:25.720 all those weird things floating in the cosmos doing strange, violent, 0:02:25.840 --> 0:02:30.359 incredible stuff and our attempts as lowly humans to understand them. 0:02:30.639 --> 0:02:33.480 Is it really possible to unravel the mysteries of the 0:02:33.560 --> 0:02:36.880 universe and lay them out inside a human mind. We 0:02:36.880 --> 0:02:40.400 will find out today and tomorrow and the next hundred 0:02:40.440 --> 0:02:43.200 episodes of our podcast. Yeah, because you know, it sometimes 0:02:43.240 --> 0:02:45.960 feels like we're building this model of the universe kind 0:02:45.960 --> 0:02:48.040 of like we're building a whole universe kind of inside 0:02:48.080 --> 0:02:52.000 of our heads and our physics theories, almost like a hologramma. 0:02:52.240 --> 0:02:55.880 That's right. It's incredible to imagine that the whole external universe, 0:02:56.080 --> 0:03:01.240 if it even exists, might be describable inside in mind, right, 0:03:01.320 --> 0:03:04.560 Like you could represent it somehow in terms of arrangements 0:03:04.560 --> 0:03:06.800 of neurons, right, and as I think the kind of 0:03:07.000 --> 0:03:10.079 idea that makes people think, like maybe the entire universe 0:03:10.200 --> 0:03:12.440 is actually just a projection of some other kind of 0:03:12.480 --> 0:03:15.959 physical arrangement. Right. Yeah, I've always wondered like maybe our 0:03:16.000 --> 0:03:19.120 brains just aren't equipped to like understand the universe. Do 0:03:19.120 --> 0:03:21.200 you ever wonder about that? Oh, I'm almost certain that 0:03:21.240 --> 0:03:23.600 we are not capable of understanding the universe at its 0:03:23.639 --> 0:03:27.120 deepest level. So are we doomed to always not know 0:03:27.200 --> 0:03:30.360 the universe. I think there's never going to be a 0:03:30.400 --> 0:03:33.799 point where we're satisfied that we think we understand and 0:03:33.919 --> 0:03:36.360 you know, imagine the kind of super intelligence that would 0:03:36.360 --> 0:03:39.760 be necessary to like fully grasp with the universe. I 0:03:39.880 --> 0:03:42.640 think about your dog. Your dog is intelligent, but it 0:03:42.720 --> 0:03:47.040 certainly doesn't understand all the physics of the universe. And 0:03:47.120 --> 0:03:50.200 so compared to some super intelligent aliens out there, we 0:03:50.240 --> 0:03:52.480 are as small as dogs, and there's no way that 0:03:52.520 --> 0:03:55.040 we could understand the universe at the level that they do. 0:03:55.640 --> 0:03:58.560 And so you essentially have to be infinitely intelligent to 0:03:58.640 --> 0:04:02.200 understand the whole university thing. And couldn't infinite intelligence exist 0:04:02.240 --> 0:04:04.440 in the universe that that would be so that would 0:04:04.440 --> 0:04:07.240 be a lot. It would create an intelligence black hole 0:04:07.320 --> 0:04:10.360 inside its mind because you can't store that much information 0:04:10.480 --> 0:04:14.480 or that much smart in a small space. Man, we've 0:04:14.560 --> 0:04:17.159 just covered dogs and black holes and like the first 0:04:17.680 --> 0:04:21.479 three minutes and including brains. But yeah, so we talked 0:04:21.480 --> 0:04:23.279 about all of the mysterious things, and one of the 0:04:23.480 --> 0:04:26.599 favorite mysterious things that we like to talk about our 0:04:26.800 --> 0:04:30.560 black holes because they're so mysterious and it seems like, 0:04:30.760 --> 0:04:33.840 you know, that there were these black pockets in almost 0:04:33.839 --> 0:04:36.240 their own universes, and it seems like anything you throw 0:04:36.279 --> 0:04:39.120 into it can never ever come out. And they're especially 0:04:39.160 --> 0:04:42.159 wonderful and fascinating because they came out of the human 0:04:42.200 --> 0:04:45.240 mind initially. It's not something we saw in the universe. 0:04:45.279 --> 0:04:47.680 It's an idea we had. We said, if the laws 0:04:47.680 --> 0:04:50.320 of physics are the way we think they are, then 0:04:50.360 --> 0:04:54.560 these things should exist. So we like mapped something inside 0:04:54.560 --> 0:04:56.640 our minds out into the universe and then went out 0:04:56.680 --> 0:04:59.800 and actually found them. I mean it's incredible, right that 0:05:00.000 --> 0:05:03.080 think that our understanding the universe could be so sophisticated 0:05:03.120 --> 0:05:06.559 and impressive that we can predict crazy new bonker stuff 0:05:06.560 --> 0:05:09.000 out there which turns out to be real. I think 0:05:09.000 --> 0:05:12.480 that's really impressive. Yeah, yeah, good jobs, physicists. Even though 0:05:12.520 --> 0:05:17.320 we are dogs compared to intelligently nothing against dogs. Of course, 0:05:17.360 --> 0:05:19.880 dogs very smart. That's why I chose them physics example, 0:05:20.000 --> 0:05:23.880 and not cats. Right, I think cats are smarter. They're 0:05:23.880 --> 0:05:26.480 not smarter than dogs. Man, you cannot train a cat. 0:05:26.720 --> 0:05:29.360 That's proof number one. That's cats are not smarter than dogs. 0:05:29.640 --> 0:05:33.560 Maybe like cats are mathematicians and dogs are physicists. Would 0:05:33.560 --> 0:05:36.400 you say that's a fair, fair comparison. Well, if you're 0:05:36.440 --> 0:05:38.359 saying that dogs are smarter than cats, that I agree 0:05:38.400 --> 0:05:45.800 with you. Masticians are just sneakier, that's right now. But 0:05:45.880 --> 0:05:49.479 black holes are a fascinating mystery and one that began 0:05:49.520 --> 0:05:52.239 inside the human brain, but one that we still don't 0:05:52.279 --> 0:05:54.440 really understand. I mean, we found them, we see them 0:05:54.480 --> 0:05:57.760 out there, but it's a continuous source of mystery and 0:05:57.839 --> 0:06:01.240 puzzlement for people everywhere and for scientists. Yeah, and it's 0:06:01.240 --> 0:06:03.599 amazing that we've seen it, like we've found one, Like 0:06:03.880 --> 0:06:06.320 they took pictures of one sort of last year, and 0:06:06.400 --> 0:06:08.159 it's like it's real, it's there, you can see it, 0:06:08.160 --> 0:06:10.040 and it looks like what we thought they looked like. 0:06:10.120 --> 0:06:11.960 That's right. The picture of the black hole shows you 0:06:12.000 --> 0:06:15.839 all the incredible gas swirling around it that's trying desperately 0:06:16.000 --> 0:06:19.080 to avoid falling into the black hole and in the 0:06:19.120 --> 0:06:21.640 process is bouncing around against all the other gas and 0:06:21.680 --> 0:06:24.359 emitting lots of radiations. So we're not seeing the black 0:06:24.360 --> 0:06:27.320 hole directly, you know, although we see a black spot there, 0:06:27.480 --> 0:06:32.400 we're seeing mostly the swirling, chaotic, crazy gas that's surrounding. Yeah. 0:06:32.400 --> 0:06:34.520 I guess you're right, because I mean, we see the 0:06:34.520 --> 0:06:37.400 black center, but there's nothing to see there because nothing 0:06:37.440 --> 0:06:39.800 can come out, or at least that's the idea of 0:06:39.800 --> 0:06:42.520 a black hole. And so the question then kind of 0:06:42.600 --> 0:06:45.919 becomes what happens to the stuff that goes into it? 0:06:46.040 --> 0:06:49.960 Is it gone forever or cannedy recovered? Yeah? Is that 0:06:50.000 --> 0:06:53.200 stuff just like hanging out inside the black hole having 0:06:53.240 --> 0:06:55.360 a great time with all the other stuff? Does it 0:06:55.440 --> 0:06:58.080 get squeezed into some new form of matter? Is it 0:06:58.160 --> 0:07:00.240 all in a singularity in the middle. It's of the 0:07:00.320 --> 0:07:03.440 deepest questions in physics what's going on inside a black 0:07:03.480 --> 0:07:06.080 hole and what happened to the stuff that fell in? 0:07:06.240 --> 0:07:08.560 So today on the podcast we'll be asking the question 0:07:13.320 --> 0:07:18.040 those a black hole destroy information? I guess that's an 0:07:18.080 --> 0:07:21.840 interesting question because you know, it's kind of like asking 0:07:21.840 --> 0:07:23.760 what happens to stuff that goes in, Like does it 0:07:23.800 --> 0:07:28.720 get destroyed like obliterated? Does it become pure energy, unadultered, 0:07:29.000 --> 0:07:32.320 unfiltered energy that you can't make out what it is? 0:07:32.560 --> 0:07:34.760 Or does it you know, does a cork stay a 0:07:34.800 --> 0:07:37.080 cork inside of the black hole? And does it still 0:07:37.280 --> 0:07:39.840 fly around and doesn't even know it's in a black hole? Yeah? 0:07:39.920 --> 0:07:41.600 I mean, are you wondering about what happened to that 0:07:41.600 --> 0:07:43.720 banana you dropped into your black hole. I'm still wondering 0:07:43.720 --> 0:07:46.920 about my banana, Daniel. I want it back. My dog 0:07:46.960 --> 0:07:49.120 needs today. Do you like eating bananas when they're black, 0:07:49.120 --> 0:07:52.800 because that's probably what happened to your back. You mean 0:07:52.880 --> 0:07:55.720 it turned into a movie basically. Basically, But it's a 0:07:55.720 --> 0:07:58.480 fascinating question, like when something goes into a black hole. 0:07:58.760 --> 0:08:01.440 Is a black hole like a cosmic hard drive? Does 0:08:01.480 --> 0:08:05.040 it like just compress everything into some new arrangement but 0:08:05.120 --> 0:08:08.000 effectively keeping track of all the particles that came in, 0:08:08.400 --> 0:08:12.200 or is it actually deleting stuff from the universe, turning 0:08:12.240 --> 0:08:15.760 into some new configuration that doesn't have any information about 0:08:15.760 --> 0:08:18.400 what happened before it. That's a fascinating question. Yeah, and 0:08:18.440 --> 0:08:20.880 so we have a lot to impact here about black 0:08:20.880 --> 0:08:24.400 holes and information. But at first we, as usually, we 0:08:24.400 --> 0:08:27.000 were wondering how many people out there had heard of 0:08:27.040 --> 0:08:31.280 this question of whether black holes keep or destroy information? 0:08:31.960 --> 0:08:34.040 And so, as usual, Daniel went out there and ask 0:08:34.080 --> 0:08:36.160 people on the internet what they thought of this question. 0:08:36.200 --> 0:08:38.760 That's right, So thank you to everybody who have volunteered 0:08:38.760 --> 0:08:42.079 to answer random questions. If you're willing to participate and 0:08:42.280 --> 0:08:45.880 like to hear your uninformed speculation on the podcast right 0:08:45.960 --> 0:08:48.800 to us two questions at Daniel and Jorge dot com 0:08:49.080 --> 0:08:51.960 YouTube can answer these random questions. Think about it for 0:08:51.960 --> 0:08:54.480 a second, and what do you know about information and 0:08:54.600 --> 0:08:57.800 black holes and what goes into them? Here's what people 0:08:57.800 --> 0:09:00.720 had to say. I think the information diss inside a 0:09:00.720 --> 0:09:04.880 black hole. My understanding of Hawking radiation is that when 0:09:04.880 --> 0:09:08.000 a particle interacts with the black hole, information is lost. 0:09:08.120 --> 0:09:13.360 Therefore the black hole behaves like a garbage disposal. Ah, 0:09:13.400 --> 0:09:15.040 so I do know a little bit about this. So 0:09:15.080 --> 0:09:18.080 I read a book by Leonard Suskin which was talking 0:09:18.120 --> 0:09:21.959 about the black hole wars. Stephen Hawkins believe that they 0:09:22.000 --> 0:09:26.800 did disappear. Information did disappear, and the Suskin said it didn't. 0:09:27.200 --> 0:09:30.199 And I think it's started to do with holographic principle 0:09:31.040 --> 0:09:34.640 that basically all the data stays on the event arising. Yes, 0:09:34.720 --> 0:09:37.760 information disappears from black holes because they lose mass through 0:09:37.800 --> 0:09:41.160 Hawking radiation. They're more like garbage disposes than hard drives, 0:09:41.160 --> 0:09:43.640 since you can't retrieve any information that's stored in them. 0:09:44.080 --> 0:09:46.680 Um my guests would be that once an object is 0:09:46.679 --> 0:09:49.560 sucked into a black hole. It is obliterated into its 0:09:49.679 --> 0:09:53.200 most smallest particles that exist, and those things float around 0:09:53.200 --> 0:09:55.640 and mess around with other particles and probably no longer 0:09:55.679 --> 0:09:59.319 resemble whatever it is that they used to make up planets, bananas, 0:09:59.320 --> 0:10:02.760 bunnies or whatever it is. I think they like store 0:10:02.800 --> 0:10:06.800 information and then eventually, in like trillions and trillions and 0:10:06.840 --> 0:10:11.160 trillions of years, there's like hawking radiation that radiates, you know, 0:10:11.320 --> 0:10:14.240 and out in black holes go away. As far as 0:10:14.240 --> 0:10:18.920 I understand, physics falls apart inside a black hole. I've 0:10:18.960 --> 0:10:25.080 read that information doesn't disappear as such, and that all 0:10:25.160 --> 0:10:31.599 the information inside the black hole would be somehow readable 0:10:31.800 --> 0:10:35.520 on the horizon. Whatever goes in there just gets squished 0:10:35.559 --> 0:10:39.360 into a really tiny small space. So I'd probably say 0:10:39.360 --> 0:10:42.120 they're more like a garbage disposal. What goes in doesn't 0:10:42.120 --> 0:10:45.959 come out, I don't think so. I think it depends 0:10:45.960 --> 0:10:48.120 at the center of a black hole is which we 0:10:48.160 --> 0:10:53.760 don't know. If it's an infinite density single point, then 0:10:53.760 --> 0:10:57.240 it's probably more like a garbage disposal. But if it's not, 0:10:57.600 --> 0:11:00.560 then I would assume information can enter it and just 0:11:00.600 --> 0:11:03.560 gets trapped. I'm gonna equivocate on this, and so I 0:11:03.600 --> 0:11:08.240 shall leave it to my learned colleagues Daniel Watson and 0:11:08.480 --> 0:11:13.720 Hua Champ perhaps to answer that all so, I don't 0:11:13.760 --> 0:11:16.360 think that information disappears into the black hole. I think 0:11:17.120 --> 0:11:22.120 information is recorded on the edge of black hole. Information 0:11:22.640 --> 0:11:26.840 cannot disappear, like energy cannot disappear. All right, not a 0:11:26.840 --> 0:11:29.440 good outlook for what happens to stuff that goes into 0:11:29.440 --> 0:11:32.680 the black hole. Nobody nobody thinks it's hanging out happily inside. 0:11:33.320 --> 0:11:35.840 Nobody thinks that you're gonna eat that banana. I like that. 0:11:35.840 --> 0:11:40.120 There's basically every answer here. Information disappears, information doesn't disappear, 0:11:40.200 --> 0:11:44.800 information is radiated out, and they're basically garbage compactors. That's 0:11:44.920 --> 0:11:47.680 a wonderful variety of answers here. Thank you to everybody 0:11:47.679 --> 0:11:50.920 who participated, a wonderful variety of analogies here, Like is 0:11:51.040 --> 0:11:54.880 a garbage compactor? Is it a garbage disposal? Is it 0:11:54.920 --> 0:12:00.160 a recycling being? I don't think the universe recycles. I 0:12:00.200 --> 0:12:02.959 don't think it's like plastic in this black hole. Please, 0:12:03.200 --> 0:12:05.720 And you know what, if black holes are just the 0:12:05.760 --> 0:12:09.240 universe's compost, interesting they could be right. They break stuff 0:12:09.280 --> 0:12:12.360 down and maybe they store it for later for a 0:12:12.880 --> 0:12:16.160 universe garden, a star garden or story for never that's 0:12:16.160 --> 0:12:18.800 maybe the problem. Well, until the universe collapses and then 0:12:18.800 --> 0:12:23.000 everything gets too cycled. Right, that's a very optimistic view 0:12:23.240 --> 0:12:25.120 of what's going to happen to your banana. Well, this 0:12:25.240 --> 0:12:27.400 is an interesting topic, and so let's jump right into it. 0:12:27.800 --> 0:12:30.200 This might take a while because some of the things 0:12:30.240 --> 0:12:33.400 that we need to talk about include information and quantum mechanics. 0:12:33.640 --> 0:12:35.439 And so before we sort of get into the idea 0:12:35.520 --> 0:12:39.680 of what happens to information that goes into a black hole, 0:12:40.640 --> 0:12:43.640 let's talk about kind of information in general and how 0:12:43.720 --> 0:12:47.120 that works in a quantum reality. That's right, because one 0:12:47.160 --> 0:12:49.319 of the mysteries of black holes is what happens to 0:12:49.440 --> 0:12:52.360 the information that goes into them. And so first we 0:12:52.440 --> 0:12:55.720 have to understand, like what is information and what does 0:12:55.800 --> 0:13:00.280 quantum mechanics say about that information? Right? So, information is 0:13:00.320 --> 0:13:02.800 kind of like the arrangement of things, like the physicist. 0:13:02.840 --> 0:13:06.480 Information is not like ones and zeros or it's not like, yeah, 0:13:06.600 --> 0:13:09.719 you know a file or a number. It's more like 0:13:09.840 --> 0:13:12.040 the arrangement of things, right, Yeah, And it can be 0:13:12.200 --> 0:13:15.079 represented as ones or zeros or you know, things you 0:13:15.160 --> 0:13:17.520 print on a piece of paper. But fundamentally, it's the 0:13:17.679 --> 0:13:21.200 arrangement of the particles. It's really it's the quantum wave 0:13:21.280 --> 0:13:24.200 function that tells you where the particles are or where 0:13:24.200 --> 0:13:26.679 they are likely to be, and how they are interacting. 0:13:27.280 --> 0:13:31.000 Remember that everything, me and you and bananas and all 0:13:31.040 --> 0:13:32.760 that stuff are made out of particles, and we're all 0:13:32.800 --> 0:13:35.680 made out of the same particles. So the thing that's 0:13:35.720 --> 0:13:39.959 different between you and lava and hamsters and bananas is 0:13:40.000 --> 0:13:42.199 not the stuff you're made out of. That's really the 0:13:42.280 --> 0:13:44.400 same stuff that everything is made out of. It's how 0:13:44.520 --> 0:13:47.320 that stuff is put together. It's like if you had 0:13:47.520 --> 0:13:49.679 a book of recipes and they all had exactly the 0:13:49.760 --> 0:13:52.679 same ingredients, just had different arrangements like where you put 0:13:52.760 --> 0:13:55.959 the stuff. That's literally how things in the universe are built. 0:13:56.280 --> 0:13:58.960 And so what we mean by information from a physics 0:13:58.960 --> 0:14:01.360 point of view is just that is how the particles 0:14:01.400 --> 0:14:03.520 are put together to make this versus that, right, And 0:14:03.600 --> 0:14:06.400 it's also kind of the history of them a little bit, right, 0:14:06.440 --> 0:14:08.000 Like you can make a banana cake and I can 0:14:08.040 --> 0:14:10.480 make a banana caig, but they're going to be different 0:14:10.520 --> 0:14:13.679 bana caggs depending on you know, what the size of 0:14:13.800 --> 0:14:16.280 the pan I use, or whether I put in a 0:14:16.360 --> 0:14:17.720 little bit more of this, or a little bit more 0:14:17.760 --> 0:14:19.520 of that, or how I poured it. They're bothing that 0:14:19.560 --> 0:14:21.400 tastes like banana aig, but they're gonna be different banana 0:14:21.440 --> 0:14:25.240 caigs because they were arranged kind of with a different history. 0:14:25.360 --> 0:14:27.560 And that's right. So our two banana cream pies both 0:14:27.600 --> 0:14:30.880 have information about what happened to those bananas, how they 0:14:30.960 --> 0:14:34.440 got there, how they originally were developed and grown and 0:14:34.600 --> 0:14:37.360 blended up and and turned into the banana cream pies. 0:14:37.400 --> 0:14:40.600 Because our two banana cream pies are not identical, they 0:14:40.680 --> 0:14:44.400 contain information about how they got there. Their arrangements are 0:14:44.520 --> 0:14:48.000 unique because only one way to create that particular banana 0:14:48.040 --> 0:14:51.120 cream pie. And so you could run the clock backwards 0:14:51.280 --> 0:14:54.440 and figure out where everything came from in your pie. Yeah, 0:14:54.720 --> 0:14:56.800 So I think that kind of what you're saying is 0:14:56.920 --> 0:14:59.280 that it's like, it's kind of like if you're playing 0:14:59.280 --> 0:15:01.720 billiards or some thing, if you see all the balls 0:15:01.760 --> 0:15:03.680 kind of arranged in a particular way on the table, 0:15:03.840 --> 0:15:06.200 you can sort of backtrack how they all got to 0:15:06.720 --> 0:15:09.760 how billiard balls usually start. That's right, And that's what 0:15:09.880 --> 0:15:13.000 we mean when we say quantum mechanics does not destroy information. 0:15:13.080 --> 0:15:16.080 It says that you can tell how you got to 0:15:16.200 --> 0:15:18.320 where you are. So, just like you said in the 0:15:18.600 --> 0:15:22.800 billiard balls example, if you see balls moving on the table, 0:15:23.120 --> 0:15:24.960 you can tell how you got there. You said, well, 0:15:25.040 --> 0:15:27.680 this must have happened in a certain way. You know, 0:15:27.800 --> 0:15:31.080 Bob must have hit Alice's ball and it bounced off 0:15:31.120 --> 0:15:33.240 this wall, etcetera, etcetera. There's only one way to get 0:15:33.280 --> 0:15:37.920 to this exact particular arrangement. And so because information is 0:15:37.960 --> 0:15:41.200 not destroyed, it's all the information you need to figure 0:15:41.240 --> 0:15:44.200 out how you got here is present in this configuration. 0:15:44.560 --> 0:15:46.400 You could run the clock backwards, you can run a 0:15:46.440 --> 0:15:49.440 physics simulation backwards and figure out exactly how you got 0:15:49.520 --> 0:15:52.040 to hear or run it forward. Right like that, I 0:15:52.120 --> 0:15:54.600 think you're saying that there's no ambiguity in the universe, 0:15:54.720 --> 0:15:57.200 Like if you you come upon a crime scene, you 0:15:57.280 --> 0:16:00.160 can tell exactly what happened, like a physicist could. If 0:16:00.200 --> 0:16:02.440 you sort of rewind the universe and play the laws 0:16:02.480 --> 0:16:05.280 of physics backwards, you can sort of reconstruct what happens 0:16:05.560 --> 0:16:07.960 every time precisely. And it's really weird that this comes 0:16:08.000 --> 0:16:10.600 up in quantum mechanics because you might think, yeah, quantum 0:16:10.600 --> 0:16:12.760 mechanics is not something that's going to give you certainty 0:16:13.040 --> 0:16:15.720 that tells you you can know everything about the universe, right, 0:16:16.040 --> 0:16:18.440 because quantum mechanics is something that feels like it has 0:16:18.480 --> 0:16:22.080 a lot of built in uncertainty. And so what quantum 0:16:22.120 --> 0:16:24.600 mechanics tells you is you can always know the wave function. 0:16:24.680 --> 0:16:26.880 That's the thing that tells you where the particles are 0:16:26.960 --> 0:16:29.200 likely to be, not that you could actually know where 0:16:29.280 --> 0:16:32.720 the particles are. In the same way, you can backtrack 0:16:32.840 --> 0:16:35.240 the wave function. You can say if the particles have 0:16:35.280 --> 0:16:37.680 a certain way function that says that they're more likely 0:16:37.760 --> 0:16:39.200 to be on the left side of the table. Now 0:16:39.560 --> 0:16:42.240 you can backtrack that and tell where they were likely 0:16:42.320 --> 0:16:44.560 to be in the past, not where they actually were. 0:16:44.760 --> 0:16:46.800 It's all about the wave function. It's all about this 0:16:47.000 --> 0:16:50.760 evolving probabilities. The way so looking back into the past 0:16:50.880 --> 0:16:53.840 is also there's also probabilities or do you know for 0:16:53.960 --> 0:16:56.400 sure where the party like if like if I see 0:16:56.400 --> 0:16:58.920 an electron and I measure, you know where it is 0:16:59.000 --> 0:17:01.400 and where it's going to the best degree that I 0:17:01.480 --> 0:17:03.560 can can, I tell you where it was before and 0:17:03.600 --> 0:17:05.320 how fast it was going. No, you can only know 0:17:05.400 --> 0:17:08.760 the probabilities. You can't collapse the wave function into the 0:17:08.840 --> 0:17:11.399 past because that would have changed where it is today. 0:17:12.720 --> 0:17:15.520 But if you know the way function today right, then 0:17:15.600 --> 0:17:17.800 you can backtrack it into the past and you can 0:17:17.840 --> 0:17:21.520 propagate it into the future. Any idea is that if 0:17:21.560 --> 0:17:23.680 you look at any configuration of matter, you should be 0:17:23.720 --> 0:17:26.160 able to tell where it came from. That's the core 0:17:26.280 --> 0:17:28.200 idea that you have to understand. I see. So when 0:17:28.200 --> 0:17:31.200 you talk about information, you don't mean like where things 0:17:31.280 --> 0:17:33.840 are and where they're going, but you also kind of 0:17:33.880 --> 0:17:38.040 include these quantum probabilities as information, Like that's also information 0:17:38.160 --> 0:17:41.439 to physics, Yes, that's the actual quantum information, because they 0:17:41.440 --> 0:17:43.960 don't know where the particles are. We really just know 0:17:44.119 --> 0:17:46.760 these probabilities. And so like when we talk about like 0:17:46.880 --> 0:17:51.600 quantum teleportation copying things, we're talking about copying not the 0:17:51.640 --> 0:17:55.120 where the particles actually are, but their probabilities, because that's 0:17:55.160 --> 0:17:57.840 really what the quantum information is. It kind of feels 0:17:57.880 --> 0:18:01.680 a little unsatisfying on physicists because I feel I feel 0:18:01.680 --> 0:18:05.240 like you're telling me that information includes not knowing kind 0:18:05.280 --> 0:18:06.840 of in a way, you know what I mean, Like 0:18:07.040 --> 0:18:11.160 information includes also non information. Yeah, what's the most information 0:18:11.240 --> 0:18:14.359 that you can have about the universe is information about 0:18:14.359 --> 0:18:18.159 the probabilities, and that information cannot be destroyed. Like we 0:18:18.200 --> 0:18:20.040 don't know where the electron is. It's not like there's 0:18:20.040 --> 0:18:22.480 a fact there that's not accessible to us. It just 0:18:22.800 --> 0:18:25.639 isn't determined. But the way function is the thing that 0:18:25.720 --> 0:18:28.119 tells you that it's more probable to find it on 0:18:28.200 --> 0:18:30.880 the left side or the right side. That is totally determined. 0:18:31.119 --> 0:18:33.280 And that's the level of quantum information we can have. 0:18:33.520 --> 0:18:37.040 That's the most information that the universe allows you to 0:18:37.160 --> 0:18:39.760 have almost right, Like you know you can know the 0:18:39.840 --> 0:18:43.119 position and the velocity of a particle to a perfect 0:18:43.160 --> 0:18:46.119 degree because of the uncertainty principle, because and that's just 0:18:46.200 --> 0:18:47.960 the rule of the universe. The universe is like, nope, 0:18:48.000 --> 0:18:52.040 you can't know everything all of the time everywhere. That's right, 0:18:52.240 --> 0:18:55.280 And that's why quantum information cannot be destroyed, because the 0:18:55.400 --> 0:18:59.240 probabilities cannot be destroyed. Like if an electron is somewhere 0:18:59.320 --> 0:19:01.960 in your box now, then it is somewhere in your 0:19:02.040 --> 0:19:04.040 box in the future. You're like, out of all the 0:19:04.080 --> 0:19:06.159 probabilities in the future, they still have to add up 0:19:06.200 --> 0:19:09.480 to one. And that's why if you run the clock backwards, 0:19:09.520 --> 0:19:12.159 you should still get probabilities adding up to one in 0:19:12.200 --> 0:19:14.400 the past, and if you run it back even further, 0:19:14.480 --> 0:19:16.960 you should still get probabilities added up to one because 0:19:17.000 --> 0:19:20.679 information is not destroyed can't just disappear, because your particles 0:19:20.720 --> 0:19:23.520 don't just disappear, you don't know where they are. But 0:19:23.600 --> 0:19:26.960 the probabilities can't disappear. The probabilities can slash around, but 0:19:27.080 --> 0:19:30.000 they can't just go away. And so that's why we're 0:19:30.000 --> 0:19:32.600 so fascinated about what happens inside a black hole, because 0:19:32.640 --> 0:19:35.880 we're wondering, like, does the information inside a black hole? 0:19:36.200 --> 0:19:39.360 Does it get deleted or is it still stored in there, 0:19:39.480 --> 0:19:41.640 Like it's a black hole that has a banana versus 0:19:41.680 --> 0:19:44.560 an apple, have something different inside it that tells you 0:19:44.960 --> 0:19:47.000 that one has a banana, one has an apple, or 0:19:47.119 --> 0:19:51.480 the actually deleting stuff. Interesting? Interesting, Yeah, I get. The 0:19:51.560 --> 0:19:55.560 question is if I throw a banana and one black hole, 0:19:56.160 --> 0:19:59.000 and I throw the equivalent apple the copy of that 0:19:59.080 --> 0:20:01.240 black hole, are the two black holes different at the 0:20:01.359 --> 0:20:03.560 end or are they basically the same? That's kind of 0:20:03.560 --> 0:20:06.000 the question exactly, And quantum mechanics says they have to 0:20:06.080 --> 0:20:09.240 be different because if they're not different, then you've destroyed 0:20:09.280 --> 0:20:11.840 the information about which one got the banana and which 0:20:11.920 --> 0:20:14.280 one got the apple in a corner. Quantum mechanics, and 0:20:14.359 --> 0:20:18.560 this is a very deep, very bedrock principle. Information cannot 0:20:18.600 --> 0:20:21.119 be destroyed. Like you go to a particle theorist and 0:20:21.200 --> 0:20:24.280 you say, what if I prove the quantum mechanics doesn't 0:20:24.320 --> 0:20:26.879 preserve information, that you can delete information from the universe, 0:20:26.960 --> 0:20:29.320 then basically they just throw all their books away and 0:20:29.400 --> 0:20:32.800 we have to start everything from scratch. It's that deeply 0:20:33.000 --> 0:20:36.800 ingrained into physics. I guess it's like comparing apple black 0:20:36.800 --> 0:20:40.800 holes to banana black holes. All Right, I'm starting to 0:20:40.800 --> 0:20:42.640 feel a bit a little bit like a dog here, uh, 0:20:42.840 --> 0:20:45.520 and not fully able to grasp all this stuff. But 0:20:45.840 --> 0:20:48.840 that's kind of the nature of quantum mechanics. So let's 0:20:48.920 --> 0:20:51.240 get into whether or not black holes can destroy this 0:20:51.359 --> 0:20:54.159 quantum information, and if they can, then how do we 0:20:54.240 --> 0:21:09.159 explain it? But first let's take a quick break. All right, 0:21:09.200 --> 0:21:14.200 we're talking about weather. Black holes can destroy quantum information. 0:21:14.480 --> 0:21:17.160 And so Danny, you were telling me that quantum information 0:21:17.280 --> 0:21:21.600