Joe Rogan Experience #1631 - Brian Greene

1. 0:00 – 15:00

   (drumming music) Joe Rogan podcast,…

   1. NANarrator0:00

      (drumming music) Joe Rogan podcast, check it out. The Joe Rogan Experience.

   2. JRJoe Rogan0:06

      Train by day, Joe Rogan podcast by night. All day. (rock music) Mr. Greene, how are you, sir?

   3. BGBrian Greene0:16

      Good. How about you?

   4. JRJoe Rogan0:17

      Good to see you, man.

   5. BGBrian Greene0:18

      Good seeing you.

   6. JRJoe Rogan0:18

      What's the latest? You got a book out?

   7. BGBrian Greene0:20

      I do, yeah. The paperback of Until the End of Time is out today.

   8. JRJoe Rogan0:24

      U- Until the End of Time.

   9. BGBrian Greene0:25

      Yeah.

   10. JRJoe Rogan0:26

       That's, uh, that's heavy.

   11. BGBrian Greene0:28

       It is heavy. But it's, uh, it's a big story, but it's one that we have a nice part within, a small cameo. The human species has a cameo, so it's a, it's a human story too.

   12. JRJoe Rogan0:38

       Yeah, the human species, uh, what have we been around for, what, 300,000 years? 400,000 years?

   13. BGBrian Greene0:42

       It depends how you define the species. But yeah, that's not a bad number. Some people go back to a million or so, if you go back to early human species. But yeah, and compared to the length of time scales that compose reality from the beginning to the end, that's zero. That's nothing.

   14. JRJoe Rogan0:58

       When you... Uh, being a physicist, being a person that really does have a, a much greater grasp of the concept of infinity and of time and of the, the, just the length that the universe has existed in its current form, how do you just get through your day and not freak out? (laughs)

   15. BGBrian Greene1:18

       Well, it's because my wife says, you know, "You gotta cook dinner."

   16. JRJoe Rogan1:21

       (laughs)

   17. BGBrian Greene1:21

       So, I mean- (laughs) They're, they're things that-

   18. JRJoe Rogan1:23

       You gotta be in the moment.

   19. BGBrian Greene1:24

       They're things that you have to actually get done. But it does change your perspective in, in a significant way, because you recognize that the things that we consider to be oh, so vital and important are just this blink of an eye on the cosmological landscape-

   20. JRJoe Rogan1:41

       Yeah.

   21. BGBrian Greene1:41

       ... on the cosmological timeline, and it does change the way you approach the world when you pay attention to it. It's hard to always pay attention to it, though. Look, I mean, if I'm walking down the street and I'm thinking about quantum mechanics, I'm thinking about, you know, quantum tunneling. I'm thinking about relativity, time slowing down when I'm moving, right? So, if you're in the physics mode, you are living life differently, but who can live that way for more than a moment?

   22. JRJoe Rogan2:04

       Right.

   23. BGBrian Greene2:05

       Because life is too powerful in its intrusion on the way you actually behave in the world.

   24. JRJoe Rogan2:11

       But because of your perspective and because of your education on this, do you feel, like, almost an obligation to try to expand people's perspective?

   25. BGBrian Greene2:21

       I'd say that it's part of one of my goals of life is to do just that. You know, I don't want people to not live their lives the way they have, but I want them to be able to broaden the experience by recognizing that everyday phenomenon is a small (laughs) slice of the way the world is actually put together. And, and when you can see your life and your experiences just a tiny sliver of a reality that's, like, bizarrely strange and utterly wondrous, when you understand everything, you know, from black holes to time dilation to quantum tunneling, to all that stuff that we have discovered over the last couple hundred years, yeah, it changes things.

   26. JRJoe Rogan3:02

       Is it, uh, is it a difficult thing to get across to people? Like, do you try to think, like, what is the best way that people are gonna absorb these ideas? Because they are so-

   27. BGBrian Greene3:11

       Yeah.

   28. JRJoe Rogan3:12

       They're not abstract, but they're, th- they're so outside of the norm in terms of the way people view the world.

   29. BGBrian Greene3:19

       Yeah, yeah.

   30. JRJoe Rogan3:19

       You kinda like go, "Hey, I know you're concentrated on this, but look at that."
2. 15:00 – 30:00

   Severely limited. …

   1. JRJoe Rogan15:00

      limited.

   2. BGBrian Greene15:00

      Severely limited.

   3. JRJoe Rogan15:02

      And this concept of many worlds, so the idea is that there's multiple versions of you and multiple versions of everything that you've experienced, all the things that you see that you consider to be Austin, Texas, or the United States, or the, the world itself.

   4. BGBrian Greene15:19

      Yeah.

   5. JRJoe Rogan15:19

      There's multiple versions of this happening simultaneously. How many?

   6. BGBrian Greene15:23

      Well, in some sense, infinite-

   7. JRJoe Rogan15:25

      Oh, boy.

   8. BGBrian Greene15:25

      ... because the, the basic idea is that any outcome that is allowed by the laws of quantum physics, any outcome will take place in its own separate world. And so, when you think about every decision you've ever made, every possibility that you've ever encountered, all of the outcomes happen, and that would happen throughout all of time. So, in some sense, there's an unending number of realities that are in the grand landscape of the quantum description. Now, we hear that, and you say, "That's nuts. That sounds nutty," right? We experience one world. But if you look at the mathematics, as a guy named Hugh Everett did in 1957, he was a graduate student at Princeton, unknown, and he looked at the math. And he said, "I wanna look at the math and give it the most straightforward intrinsic interpretation." And the most economical intrinsic interpretation of the math is this one. It sounds grossly uneconomical, all these universes, but that's an output. The input is incredibly economical. You look at the equations, and this is the most straightforward interpretation. Every outcome does happen. It happens in its own world. Now, I'm not saying that I believe this, but it's definitely a worthy contender for the way that we should think about quantum mechanics.

   9. JRJoe Rogan16:47

      So, do you guys get together and bounce these ideas off each other o- on a regular basis? Like-

   10. BGBrian Greene16:53

       I- it depends who you mean by you guys.

   11. JRJoe Rogan16:54

       Y- you physicists tell us-

   12. BGBrian Greene16:55

       You, you physicists. Well, yeah, it's-

   13. JRJoe Rogan16:57

       (laughs)

   14. BGBrian Greene16:58

       So, only some. So, some physicists, when they hear about this kinda talk, they roll their eyes, and they say, "Just use the mathematics. Make predictions for what we'll see at the Large Hadron Collider. Make predictions for what we'll see in this or that laboratory. Don't try to understand it. Just do it." You know, it's the cold, so-called shut up and calculate approach-

   15. JRJoe Rogan17:21

       Hmm.

   16. BGBrian Greene17:21

       ... to quantum mechanics. And Niels Bohr, who was one, again, one of the founding pioneers of quantum mechanics, this was his perspective. I mean, Bohr basically said the goal of physics is not to tell us how the universe is in the sense of understanding it, it's just to make (laughs) predictions that we're gonna see in experiments. That's all that you should ever expect to do. There are other physicists who don't feel that way. And there are other physicists who think physics is a matter of telling us what's happening.

   17. JRJoe Rogan17:49

       Yeah.

   18. BGBrian Greene17:50

       It's gotta give us the story. It's gotta, like, peel back the curtain and give us a clear glimpse of what's happening behind the scenes. And so those of us who do have that as the goal-... do get together and-

   19. JRJoe Rogan18:02

       (laughs)

   20. BGBrian Greene18:02

       ... do talk about these things. (laughs) You know.

   21. JRJoe Rogan18:03

       Well, I'm glad you guys exist, because those shut up and do the math, and-

   22. BGBrian Greene18:07

       Yeah.

   23. JRJoe Rogan18:08

       ... those guys, they're not gonna help me. Like, that-

   24. BGBrian Greene18:10

       Yeah.

   25. JRJoe Rogan18:11

       ... I'm, I'm not gonna be able to understand that. Like, you are a bridge to someone like me e- having the slimmest grasp of an-

   26. BGBrian Greene18:17

       Right.

   27. JRJoe Rogan18:17

       ... understanding of what this stuff is all about.

   28. BGBrian Greene18:19

       Although those guys would say that I am doing you a disservice.

   29. JRJoe Rogan18:22

       How so?

   30. BGBrian Greene18:23

       They would say that I should convince you that there is no deeper intuition that you're missing, that the only way to understand what's going on is you learn the math, you do the calculations, and looking for anything else is looking for too much. Now, I don't feel that way. I feel that in the end of the day, when we understand the world deeply, it does give us insights into what's actually happening. The question you asked, "What's happening in quantum entanglement?" is, in my view, the right question to ask. Unfortunately, I can't give you a good enough (laughs) answer today, even though mathematically we understand it perfectly. I think one day we'll go beyond that. A- and there is work happening today. There are people who suspect that quantum entanglement is nothing but another idea of Einstein's in disguise, wormholes.
3. 30:00 – 45:00

   (smacks lips) Now, you were…

   1. BGBrian Greene30:00

      a concrete way where you can have back-to-back photons that will travel arbitrarily (laughs) far apart if they don't encounter anything else, that will be quantum entangled.

   2. JRJoe Rogan30:08

      (smacks lips) Now, you were talking about integrated circuits. Now, I hear a lot of talk about quantum computing-

   3. BGBrian Greene30:16

      Yeah.

   4. JRJoe Rogan30:17

      ... and I don't understand what that is, but everybody's telling me that it's gonna revolutionize computing.

   5. BGBrian Greene30:21

      Yeah.

   6. JRJoe Rogan30:21

      How so?

   7. BGBrian Greene30:22

      Well, with- as with everything, you have to interrogate precisely what one means by revolutionize everything. Maybe in some rough sense that's true. But let me just first say what it is-

   8. JRJoe Rogan30:33

      Okay.

   9. BGBrian Greene30:33

      ... and then say what the possibilities are. So, imagine that you have a computer that can access, I'll use one particular lang- access the many worlds of quantum mechanics. Now, when you're carrying out a calculation, you don't have the calculation solely take place in one universe, you have it take place in a whole collection of parallel universes, allowing you in some sense to divide up the calculation, and in parallel have it take place across this spectrum of universes. Clearly that will rapidly speed up the calculation because now it's no longer happening in one universe, you split it across many universes. So, in some sense, quantum computing is trying to leverage that quality of quantum mechanics. Now, that's one language using the language of many worlds. You don't have to use the language. You can also use just the language of probabilities. So, if you have a particle, like an electron, normally in a classical world you'd say it's either here or there. In a quantum world, our world, it can be in a mixture of here and there. If it's in a mixture of here and there, you can do calculations here and there. Whereas in a classical world you could either do the calculation here or there. So, it's basically substantially increasing the places where calculations take place, thereby substantially decreasing the amount of time that it takes these calculations to be accomplished.

   10. JRJoe Rogan32:09

       And but- by what mechanism? Like, what is- what separates quantum-

   11. BGBrian Greene32:13

       Yeah.

   12. JRJoe Rogan32:13

       ... computing from regular computing? How is it-

   13. BGBrian Greene32:14

       Yeah, so- so, in regular computing, you- you have quantum qualities, because like I said, the integrated circuit, you need it to understand quantum mechanics to guide the motion of the particle through the integrated circuit. But in the end of the day, a traditional computer, a classical computer if we will, stores information as bits, zeros and ones. So, you have one bit that's either a zero, another bit that's either a one, and through that you can store information and manipulate information, and that's what computation is all about. The quantum computer changes the bit to the so-called qubit. What is a qubit? A qubit is a specially defined and constructed digit that can be in a mixture of zero and one. And specifically, the way we usually do this is we have what are known as spin systems. So, an electron has a spin, like a little top, and it can either spin counterclockwise that we call spin up, or clockwise that we call spin down. In a classical world, the electron is either this or this. In the quantum world, it can be a mixture. And so literally these quantum computers have these spin systems that are in these mixtures of up and down simultaneously, and that allows them to do multiple computations simultaneously that allows them to decrease the time it takes to carry out the computation. That's- that's the essence of the idea.

   14. JRJoe Rogan33:40

       Is the structure of the computer different? Like-

   15. BGBrian Greene33:42

       Totally.

   16. JRJoe Rogan33:42

       So, regular computer has a motherboard-

   17. BGBrian Greene33:45

       Yeah.

   18. JRJoe Rogan33:45

       ... it has a processor, it has a hard drive. What is a quantum computer structured like?

   19. BGBrian Greene33:49

       You know, if you see some of these things, they look... I've heard them described, and it's not a bad description, as sort of like chandeliers. You- you've got spin systems in arms of the chandeliers, and you have cooling systems that are vital to these computers because if there's heat that comes into the system, it can destroy this delicate mixture of up and down simultaneously. So, they're far more delicate, and it is much more difficult to, at this stage, have the number of bits. So, an ordinary c- computer can have as many bits as you want. As you say, just, you know, put more boards, expand, you know, the random access memory. You know, it's all up to you, the user. For quantum computers, you've gotta make sure that all these qubits are working together in order that they can perform these calculations. And it's very hard to have a whole lot of qubits maintain the so-called quantum coherence that allows them to work together. So, the maximum number of qubits in quantum computers that have been built, it's only at 50. Very small relative to the number of bits that we're familiar with, you know, in... We're talking about gigabits, right-

   20. JRJoe Rogan35:01

       Mm-hmm.

   21. BGBrian Greene35:01

       ... when you're talking about your- your billions of bits. So- so that is for the future, but there doesn't seem to be a fundamental obstacle to building a quantum computer that has, you know, a large number of these qubits, and in that way in principle being able to do calculations exponentially more quickly. That's the rough idea.

   22. JRJoe Rogan35:19

       How far away are we from implementing quantum computing in daily life? Like is it- i- d- is it a cooling issue? Is it a- an issue of just, uh, m- expanding our- our understanding of how to construct these things? Like-

   23. BGBrian Greene35:32

       Yeah. Um, there are- there are those in the field who are careful to say that they don't think that we'll ever have quantum computing in everyday life. And the reason for that is largely, you know, the- the cooling issue-

   24. JRJoe Rogan35:47

       Mm-hmm.

   25. BGBrian Greene35:48

       ... and it has to do with the...... difficulty in maintaining the stability of these devices. They're so delicate. Whereas, you know, you drop your laptop, you may crack it or something. But, you know, for the most part, you drop your phone and it's fine.

   26. JRJoe Rogan36:02

       Mm-hmm.

   27. BGBrian Greene36:02

       And so, there are those who say that we will never have these things in daily life. They'll always be highly specialized, you know, in laboratories that we somehow make use of, as opposed to carry around in our pocket. But the same was (laughs) said about ordinary computers, you know, 60, 70, 80 years ago, when a computer in those days filled an entire room-

   28. JRJoe Rogan36:21

       Right.

   29. BGBrian Greene36:21

       ... with all these vacuum tubes. Who ever thought that we'd be walking around in our pocket with something more powerful than that kind of device? So, I'm-

   30. JRJoe Rogan36:28

       Just 50 years later.
4. 45:00 – 1:00:00

   Yeah. …

   1. JRJoe Rogan45:00

      or whatever these weird human quirks are, and they could figure out a way to create works of art.

   2. BGBrian Greene45:07

      Yeah.

   3. JRJoe Rogan45:07

      They could figure out a way to s- to do things that are uniquely moving to us, and that's what's gonna be really weird.

   4. BGBrian Greene45:14

      To-

   5. JRJoe Rogan45:14

      If a computer can write a book that blows you away, a computer can write a better version of The Great Gatsby.

   6. BGBrian Greene45:21

      Right.

   7. JRJoe Rogan45:21

      You know? If-

   8. BGBrian Greene45:22

      Yeah. No, I agree. And it's gon-... I think it will happen 'cause look-

   9. JRJoe Rogan45:25

      Yeah.

   10. BGBrian Greene45:25

       ... I mean, what is it that distinguishes us as a species? Many people will point to different things, but one certainly is that we are deeply social as a species, and because of that, we've been able to learn from each other and therefore not had to start each generation from scratch. Right? Many other animals in the animal kingdom, they basically, each generation kind of start from scratch. They don't have books that they can read about discoveries of an earlier age. They don't have teachers. I mean, some do, but they don't have teachers that can give them, uh, you know, the corpus of knowledge going back hundreds of years. They probably don't have universities where they can learn about what happened over the last 500 years and therefore not have to start from scratch. And so, when you talk about the capacities of artificial systems, they will be far more social than we. Why? For exactly the reason you're saying. We typically learn from a, a handful of masters that had, you know... Albert Einstein's work, all physicists learn about it, you know. Artists maybe learn about the work of Rembrandt or Picasso, you know, the masters. But an artificial system can learn from every single other artificial system. There's no limit to the connectivity between those systems. So, whatever pattern a given artificial system figures out, they'll all know about that pattern simply by communicating among themselves. In our environment, we only communicate with a small number of other human beings over the course of our lives. And again, some of that knowledge is stored, and therefore it becomes widely accessible. All knowledge gleaned by any artificial being within the network will be immediately shared by every other artificial being within the network, and therefore, the very thing that makes us special, the collective culture that allows us each generation to build on the insights of the previous and not have to go back to the beginning, (laughs) that will be amplified enormously for artificial systems. So, why wouldn't they be able to create the greatest work and the greatest novels? I think that will absolutely be the case.

   11. JRJoe Rogan47:32

       Yeah. We, we have information that somehow or another passed from parent to child somehow, through genes.

   12. BGBrian Greene47:38

       Yeah.

   13. JRJoe Rogan47:39

       And we, we see it not just in us, but we see it in the animal world. Like, you can have a dog, and for whatever reason, that dog knows it's supposed to lift its leg to pee on a tree.

   14. BGBrian Greene47:48

       Yeah.

   15. JRJoe Rogan47:48

       And no one has to teach it. And there's other, you know, weird beha-... Like, I have a, a golden retriever.

   16. BGBrian Greene47:53

       Yeah.

   17. JRJoe Rogan47:53

       He loves bringing things back.... you throw things, he gets them, and he brings them right back. Some dogs, it's hard to get them to bring things back. Not golden retrievers. He's got it somehow or another in his system-

   18. BGBrian Greene48:05

       Yes.

   19. JRJoe Rogan48:05

       ... to bring things back to you.

   20. BGBrian Greene48:06

       Yeah. For-

   21. JRJoe Rogan48:07

       It's, it's natural.

   22. BGBrian Greene48:08

       For sure. You know, there's this whole area of evolutionary psychology which applies the ideas of evolution by natural selection, not just to the physical system, that's where we normally learn about it in school. You know, we see how a given species changes over time, because there's a random mutation, and that mutation allows that individual to better adapt to the environment, and therefore, that particular morphology, that change, spreads widely through subsequent generations. That's normally how we talk about evolution by natural selection. But as you're saying, it also applies to behaviors. There are certain behaviors that allows an individual to better navigate in the ancestral world, and that behavior, if it had some genetic basis, can be passed on to the next generation, and passed on to generations still. So, yeah, lifting up the leg to pee is one example of that, but there are many other behaviors. I mean, a canonical example is we have a predilection. We like sweet things, we like fats, right?

   23. JRJoe Rogan49:07

       Mm-hmm.

   24. BGBrian Greene49:07

       Why? Well, the evolutionary psychologists have noted that in the ancestral world, those of our forebears who had a tendency to eat ripened fruits, or to eat nuts, they stored up on calories, so that when times turned lean, they were the ones that survived. And therefore, they passed on that propensity to enjoy sweets and fats, and we are the recipients of that long chain of behavioral predilections. So, that's certainly the case. But the thing is, we then go beyond that. We are able to store, culturally, information and breakthroughs from an earlier generation that may not have any relevance to our DNA, and yet we can pass that knowledge on. Right? So, Newton's ideas and Einstein's ideas, we will continue to pass these ideas on, and I presume they're not gonna be imprinted in anybody's DNA. Maybe one day they will be, but certainly at the moment, they're not. Your golden retriever, that kind of dog is- you were saying was a golden?

   25. JRJoe Rogan50:07

       Yeah.

   26. BGBrian Greene50:08

       I- it can't do that. The, the, the, the mother of your golden retriever, and the mother of that mother, and going all the way back, they pretty much all lifted up their leg and peed. And there wasn't a whole lot else that got passed through from sort of cultural heritage of things that one dog discovered that could then pass on to subsequent generations. So, what makes us special is we certainly have behaviors that are passed through the lineage in this manner of evolutionary psychology, but we also have culture. And culture allows us to store the insights, the breakthroughs of an earlier age, allowing us to get to where we have gotten. I mean, I've often wondered if I got stuck on a desert island, how much of the world would I be able to, like, recreate? Even how much of the world of physics would I be ... Uh, not much. Right? Because I have assumed so much from earlier generations. Like, I don't know that I could, I, I couldn't build an integrated circuit. I couldn't recreate a computer. I could write, I could write down the laws of general relativity and quantum mechanics, and I could work out for them the mathematics of black holes and entanglement. That sort of stuff I could do. But there's so much of the culture (laughs) that I, I have no capacity to reproduce. And that's our collective socialization that we're able to benefit from the fact that we all talk to each other, and we all know about things that happened in an earlier age. And that is what makes us special, and that is what will, we will also pass on to artificial systems, 'cause they're gonna be able to do that too.

   27. JRJoe Rogan51:42

       It seems like almost a race in time to see if we can get to this quantum computing level on a personal, in, in, in a personal way that you can use before we destroy ourselves.

   28. BGBrian Greene51:54

       Yeah.

   29. JRJoe Rogan51:55

       Because if you go back to think about culture and the way we interact with information, how much it's changed since, like, you know, the 1700s, the 1500s, when things had to be written down-

   30. BGBrian Greene52:05

       Yeah.
5. 1:00:00 – 1:15:00

   That sounds like a…

   1. GPGuest’s assistant/third participant1:00:00

      like a computer.

   2. JRJoe Rogan1:00:07

      That sounds like a shitty-

   3. GPGuest’s assistant/third participant1:00:08

      Right. That sounds like it's-

   4. JRJoe Rogan1:00:08

      ... Nirvana cover band from Portland. (laughs)

   5. GPGuest’s assistant/third participant1:00:10

      It's not as good, that's why I didn't want it to stay on.

   6. BGBrian Greene1:00:11

      But you had The Doors there too, right? The-

   7. JRJoe Rogan1:00:13

      Yeah, let me hear-

   8. GPGuest’s assistant/third participant1:00:14

      Yeah. Uh-

   9. JRJoe Rogan1:00:14

      There's a Hendrix one too?

   10. GPGuest’s assistant/third participant1:00:15

       There's... I did not listen to that at all.

   11. JRJoe Rogan1:00:16

       Well, give me some Hendrix-

   12. GPGuest’s assistant/third participant1:00:17

       Okay.

   13. JRJoe Rogan1:00:17

       ... 'cause I'm a giant Hendrix fan. I'll tell you if this is horse shit. (heavy metal music plays)

   14. GPGuest’s assistant/third participant1:00:31

       Not bad.

   15. JRJoe Rogan1:00:38

       That's not bad. Let it go.

   16. GPGuest’s assistant/third participant1:00:50

       Damn. Very good.

   17. JRJoe Rogan1:01:14

       That's pretty fucking good.

   18. GPGuest’s assistant/third participant1:01:15

       They may have had an audio engineer that's someone that knows how to mix music to add to how good this sounds 'cause it couldn't come up correctly, but-

   19. JRJoe Rogan1:01:20

       Maybe.

   20. BGBrian Greene1:01:21

       But even that, that will... is again-

   21. JRJoe Rogan1:01:23

       Right.

   22. BGBrian Greene1:01:23

       ... pattern recognition-

   23. GPGuest’s assistant/third participant1:01:24

       Yeah. Yeah. I've got-

   24. BGBrian Greene1:01:24

       ... putting things together. So, look, that's-

   25. JRJoe Rogan1:01:25

       That's a great example of-

   26. BGBrian Greene1:01:27

       Yeah. But that's all the, we do, right?

   27. JRJoe Rogan1:01:28

       Yeah.

   28. BGBrian Greene1:01:28

       That's what we do. So why can't comp-... All we do is mix match patterns, mono- modify patterns. You know, that's, that's all the we do anyway.

   29. JRJoe Rogan1:01:36

       That... If I'm, if I'm being cynical, and I often am-

   30. BGBrian Greene1:01:38

       Mm-hmm.
6. 1:15:00 – 1:21:24

   So, as- …

   1. BGBrian Greene1:15:00

      description of a black hole in terms of what's known as the holographic description. It's as if there's a two-dimensional world that surrounds any given three-dimensional world that has exactly the same physics as the three-dimensional world that we're familiar with, and yet it describes it in a completely different language. So, a black hole gravity is obviously essential. That's how a black hole forms. But in this dictionary that physicists have developed, there's a description of a black hole that doesn't involve gravity, only involves quantum mechanics. And the beautiful thing is the quantum processes in that quantum world mimic the kinds of processes that people have been developing for quantum computing, quantum error correction code, and there's a dictionary that people have proposed for that quantum language on the holographic boundary with physics in the interior. And the dictionary shows that the quantum error correcting code may be the reason why space-time itself holds together. So, there's this bizarre way in which everything that we know about in the world around us has a translated dictionary version in a different world that lacks gravity but has quantum mechanics. And so people are u- using some of the insights from quantum computing to understand questions about black holes and space time.

   2. JRJoe Rogan1:16:24

      So, as-

   3. BGBrian Greene1:16:24

      Is that strange or what?

   4. JRJoe Rogan1:16:25

      That's so strange. So, as quantum computing expands, much like as computing expands, if you go back to the early NASA computers that filled up a whole room, we can extrapolate that as we get better at this and you look 50 years down the line from now, quantum computing will be the standard, it would be the norm.

   5. BGBrian Greene1:16:42

      Yep.

   6. JRJoe Rogan1:16:42

      And it would probably radically alter our understanding of everything.

   7. BGBrian Greene1:16:47

      Including black holes, yeah.

   8. JRJoe Rogan1:16:48

      Including black holes.

   9. BGBrian Greene1:16:49

      That's right. So, there's a real possibility that the language that we use for space-time and black holes may bear a profound imprint of the language that we are developing to understand quantum computing, quantum computers.

   10. JRJoe Rogan1:17:04

       I was just reading some article about black holes roaming through the universe, and that some of them, some of them, they're detached from galaxies, right?

   11. BGBrian Greene1:17:11

       They can be. I mean, oftentimes people think about black holes as these gargantuan structures that form from collapsed stars. There's a big one in the center of our Milky Way galaxy, weighs four million times that of the sun. The photograph of a black hole in the galaxy M87 that got the world excited a couple of years back, 55 million light years away, billions of times the mass of the sun. But the reality is anything, if you compress it enough, becomes a black hole. If you take an orange and you squash an orange down (laughs) sufficiently small, according to Einstein, it becomes a black hole.

   12. JRJoe Rogan1:17:46

       (laughs)

   13. BGBrian Greene1:17:46

       So, these things don't have to be gargantuan. The flip side of it is, we also typically have an intuition that black holes are really dense, right? That's usually the way we think about them. But if you make something sufficiently large, regardless of how low its density is, it will also become a black hole. So, you can make a black hole out of air, by just having enough air. If you have enough air, a sufficiently large sphere of air, it would become a black hole too, with a density of air. So, all the intuitions (laughs) that we typically have about black holes, that they have to be dense and they have to be gargantuan, not right.

   14. JRJoe Rogan1:18:24

       So, black holes are just a part of the elemental structure of reality itself.

   15. BGBrian Greene1:18:30

       Yeah. When you look at Einstein's equations, right in his mathematics, there's a little formula (laughs) that you can see where it says, if you have any mass M, whatever mass you want, and you squeeze it into a radius, R, that's less than two times Newton's constant, 2G, times M, divided by C squared, speed of light squared... A formula. Details don't matter. But you take any mass, if the radius within which that mass sits is less than 2GM over C squared, it is a black hole. Period. End of story. According to Einstein. Now, Einstein left out quantum mechanics. Weirdly, right? Because his Nobel Prize was for quantum mechanics. It was for a paper he wrote in 1905 about the photoelectric effect. But he never really believed that quantum mechanics was the true description of the world. And when he was developing the general theory of relativity, he was just thinking about gravity and not quantum mechanics. Stephen Hawking came along in 1974 and started to inject quantum mechanics into our understanding of things like black holes. And that's where Hawking proved that black holes are not completely black. He showed that black holes allow a certain amount of radiation to leak out of their surface, leak out of the event horizon, or leak out from just beyond the edge of the event horizon. And so, yes, when you think about black holes, as far as we can tell, they are a fundamental quality of the world. But you have to include quantum physics to truly understand them, and that's the cutting edge of what's happening right now.

   16. JRJoe Rogan1:19:59

       So, they're a fundamental quality of the world, but they're also in the center of every galaxy?

   17. BGBrian Greene1:20:04

       It seems to be the case. The Sloan Digital Sky Survey did a wonderful study of a vast number of galaxies, and I've seen these wonderful images where they put, like, a little red circle around all those galaxies that have a black hole in their center, and there are red circles all over that imagery. So, it seems to be a ubiquitous quality, that black holes are at the center of galaxies, and those are typically gargantuan black holes, millions or billions of times the mass of the sun.

   18. JRJoe Rogan1:20:35

       Do we know why they exist at the center of a galaxy?

   19. BGBrian Greene1:20:39

       Y- y- y- uh, n- you know, there's still a lot of uncertainty about galactic formation. You know, some have suggested that early stars, which were quite large compared to more modern stars, when they exhausted their nuclear fuel and they collapsed in on each other, they created black holes that were large. And then they continued to suck in more material from the environment, and they grew larger and larger still. So, that's sort of one rough way that people think about how these massive, enormous black holes may have formed, but it's uncertain. LIGO, you know, this Laser Interferometer Gravitational Wave Observatory, gravitational waves, it- it took headlines a few years ago when it detected the first ripples in the fabric of space. It detected them from two black holes-

Episode duration: 2:42:28