Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions

00:00:00.000 | Black holes curve space and time around them in the way that we've been describing.

00:00:03.300 | Things follow along the curves in space.

00:00:05.400 | If the black holes move around, the curves have to follow them, right?

00:00:10.460 | But they can't travel faster than the speed of light either.

00:00:13.340 | So what happens is black holes, let's say, move around.

00:00:16.500 | Maybe I've got two black holes in orbit around each other.

00:00:18.760 | That can happen.

00:00:19.460 | It takes a while.

00:00:20.980 | A wave is created in the actual shape of space.

00:00:23.780 | And that wave follows the black holes.

00:00:26.520 | Those black holes are undulating.

00:00:28.440 | Eventually, those two black holes will merge.

00:00:30.380 | And as we were talking about, it doesn't take an infinite time, even though there's time dilation, because they're both so big.

00:00:36.500 | They're really deforming space-time a lot.

00:00:38.860 | I don't have a little tidy marble falling across an event horizon.

00:00:42.020 | I have two event horizons.

00:00:43.160 | And in the simulations, you can see it bobble.

00:00:45.560 | And they merge together.

00:00:47.840 | They make one bigger black hole.

00:00:49.360 | And then it radiates in the gravitational waves.

00:00:51.940 | It radiates away all those imperfections.

00:00:54.600 | And it settles down to one quiescent, perfectly silent black hole that's spinning.

00:01:00.380 | Beautiful stuff.

00:01:01.460 | And it emits E equals mc squared energy.

00:01:03.580 | So the mass of the final black hole will be less than the sum of the two starter black holes.

00:01:10.040 | And that energy is radiated away in this ringing of space-time.

00:01:14.540 | It's really important to emphasize that it's not light.

00:01:17.940 | None of this has to do literally with light that we can detect with normal things that detect light.

00:01:25.260 | X-rays form a light.

00:01:26.540 | Gamma rays are a form of light.

00:01:27.860 | Infrared, optical, this whole electromagnetic spectrum, none of it is emitted as light.

00:01:32.960 | It's completely dark.

00:01:34.060 | It's only emitted in the rippling of the shape of space.

00:01:36.580 | A lot of times it's likened closer to sound.

00:01:39.240 | Technically, we've kind of argued.

00:01:40.800 | I mean, I haven't done an anatomical calculation.

00:01:43.220 | But if you're near enough to two colliding black holes, they actually ring space-time in the human auditory range.

00:01:49.440 | The frequency is actually in the human auditory range.

00:01:53.240 | The following is a conversation with Jenna Levin, a theoretical physicist and cosmologist specializing in black holes, cosmology of extra dimensions, topology of the universe, and gravitational waves in space-time.

00:02:17.920 | She has also written some incredible books, including How the Universe Got Its Spots on the topic of the shape and the size of the universe,

00:02:26.460 | A Madman Dreams with Touring Machines on the topic of genius, madness, and the limits of knowledge,

00:02:33.540 | Black Hole Blues and other songs from outer space on the topic of LIGO and the detection of gravitational waves,

00:02:43.480 | and Black Hole Survival Guide, all about black holes.

00:02:48.520 | This was a fun and fascinating conversation.

00:02:53.100 | This is a Lex Friedman podcast.

00:02:55.340 | To support it, please check out our sponsors in the description.

00:02:58.440 | And now, dear friends, here's Jenna Levin.

00:03:02.700 | I should say that you sent me a message about not starting early in the morning, and that made me feel like we're kindred spirits.

00:03:09.960 | Yeah.

00:03:10.980 | You wrote to me, when the great physicist Sidney Coleman was asked to attend a 9 a.m. meeting, his reply was,

00:03:17.700 | I can't stay up that late.

00:03:20.020 | Yeah.

00:03:20.640 | Classic.

00:03:21.620 | Sidney was beloved.

00:03:23.480 | I think all the best thoughts, honestly, maybe the worst thoughts, too, are all come at night.

00:03:27.820 | There's something about the night, maybe it's the silence, maybe it's the peace all around, maybe it's the darkness, and you just, you can be with yourself and you can think deeply.

00:03:38.120 | I feel like there's stolen hours in the middle of the night, because it's not busy, your gadgets aren't pinging, there's really no pressure to do anything, but I'm often awake in the middle of the night.

00:03:49.840 | And so, it's sort of like these extra hours of the day.

00:03:52.660 | I think we were exchanging messages at four in the morning.

00:03:55.060 | Okay.

00:03:56.560 | So, in that way, many other ways were kindred spirits.

00:03:59.320 | So, let's go.

00:04:00.520 | In one of the coolest objects in the universe, black holes, what are they?

00:04:05.780 | And maybe even a good way to start is to talk about how are they formed?

00:04:10.860 | Mm.

00:04:11.540 | Yeah.

00:04:12.920 | In a way, people often confuse how they're formed with the concept of the black hole in the first place.

00:04:19.000 | So, when black holes were first proposed, Einstein was very surprised that such a solution could be found so quickly, but really thought nature would protect us from their formation.

00:04:30.860 | And then nature thinks of a way.

00:04:31.940 | Nature thinks of a way to make these crazy objects, which is to kill off a few stars.

00:04:35.920 | But then I think that there's a confusion that dead stars, these very, very massive stars that die, are synonymous with the phenomenon of black hole.

00:04:45.580 | And it's really not the case.

00:04:47.380 | Black holes are more general and more fundamental than just the death state of a star.

00:04:53.540 | But even the history of how people realize that stars could form black holes is quite fascinating because the entire idea really just started as a thought experiment.

00:05:04.640 | And if you think of, it's 1915, 1916, when Einstein fully describes relativity in a way that's the canonical formulation.

00:05:14.000 | It was a lot of changing back and forth before then.

00:05:17.100 | And it's World War I, and he gets a message from the Eastern Front from a friend of his, Carl Schwarzschild, who solved Einstein's equations.

00:05:25.660 | You know, between sitting in the trenches and, like, cannon fire, it was joked that he was calculating ballistic trajectories.

00:05:34.600 | He's also perusing the proceedings of the Prussian Academy of Sciences, as you do.

00:05:39.920 | And he was an astronomer who had enlisted in his 40s.

00:05:45.120 | And he finds this really remarkable solution to Einstein's equations.

00:05:48.600 | And it's the first exact solution.

00:05:50.580 | He doesn't call it a black hole.

00:05:52.260 | It's not called a black hole for decades.

00:05:54.700 | But what I love about what Schwarzschild did is it's a thought experiment.

00:05:58.540 | It's not about observations.

00:06:00.060 | It's not about making these things in nature.

00:06:02.420 | It's really just about the idea.

00:06:05.360 | He sets up this completely untenable situation.

00:06:09.400 | He says, imagine I crush all the mass of a star to a point.

00:06:13.760 | Don't ask how that's done.

00:06:15.280 | Because that's really absurd.

00:06:16.360 | But let's just pretend.

00:06:18.460 | And let's just imagine that that's a scenario.

00:06:21.140 | And then he wants to decide what happens to space-time if I set up this confounding but somehow very simple scenario.

00:06:30.140 | And really what Einstein's equations were telling everybody at the time was that matter and energy curves space and time.

00:06:36.980 | And then curved space-time tells matter and energy how to fall once the space-time's shaped.

00:06:42.120 | So he finds this beautiful solution.

00:06:44.160 | And the most amazing thing about a solution is he finds this demarcation, which is the event horizon, which is the region beyond which not even light can escape.

00:06:54.900 | And if you were to ask me today, all these decades, over a hundred years later, I would say that is the black hole.

00:07:00.880 | The black hole is not the mass crushed to a point.

00:07:04.080 | The black hole is the event horizon.

00:07:06.480 | And the event horizon is really just a point in space-time or a region in space-time.

00:07:12.300 | It's actually, in this case, a surface in space-time.

00:07:15.380 | And it marks a separation in events, which is why it's called an event horizon.

00:07:20.780 | Everything outside is causally separated from the inside insofar as what's inside the event horizon can't affect events outside.

00:07:30.100 | What's outside can affect events inside.

00:07:32.620 | I can throw a probe into a black hole and cause something to happen on the inside.

00:07:37.520 | But the opposite isn't true.

00:07:39.300 | Somebody who fell in can't send a probe out.

00:07:41.820 | And this one-way aspect really is what's profound about the black hole.

00:07:45.740 | Sometimes we talk about the black holes being nothing because at the event horizon, there's really nothing there.

00:07:52.780 | Sometimes when we think about black holes, we want to imagine a really dense, dead star.

00:07:59.180 | But if you go up to the event horizon, it's an empty region of space-time.

00:08:04.000 | It's more of a place than it is a thing.

00:08:07.080 | And Einstein found this fascinating.

00:08:09.920 | He helped get the work published.

00:08:11.740 | But he really didn't think these would form in nature.

00:08:14.680 | I doubt Carl Schwarzschild did either.

00:08:17.120 | I think they thought they were solving theoretical, mathematical problems, but not describing what turned out to be the end state of gravitational collapse.

00:08:31.660 | And maybe the purpose of the thought experiment was to find the limitations of the theory.

00:08:35.220 | So you find the most extreme versions in order to understand where it breaks down.

00:08:41.540 | Yeah.

00:08:42.080 | And it just so happens in this case that might actually predict these extreme kinds of objects.

00:08:48.460 | It does both.

00:08:49.760 | So it also describes the sun from far away.

00:08:53.400 | So the same solution does a great job helping us understand the Earth's orbit around the sun.

00:08:59.060 | It's incredible.

00:08:59.960 | It does a great job.

00:09:00.840 | It's almost overkill.

00:09:01.840 | You don't really need to be that precise as relativity.

00:09:05.940 | And yes, it predicts the phenomenon of black holes, but doesn't really explain how nature would form them.

00:09:11.880 | But then it also, on top of that, does signal the breakdown of the theory.

00:09:16.020 | I mean, you're quite right about that.

00:09:17.280 | It actually says, oh man, but you go all the way towards the center, and yeah, this doesn't sound right anymore.

00:09:24.380 | Sometimes I liken it to, you know, it's like a dying man marking in the dirt that something's gone wrong here, right?

00:09:33.360 | It's signaling that there's some culprit, there's something wrong in the theory.

00:09:37.560 | And even Roger Penrose, who did this general work trying to understand the formation of black holes from gravitational collapse, he thought, oh yeah, there's a singularity that's inevitable.

00:09:51.560 | It's in every, there's no way around it once you form a black hole.

00:09:56.140 | But he said, this is probably just a shortcoming of the fact that we've forgotten to include quantum mechanics, and that when we do, we'll understand this differently.

00:10:07.480 | So according to him, the closer you get to the singularity, the more quantum mechanics comes into play, and therefore, there's no singularity, there's something else.

00:10:14.740 | I think everybody would say that.

00:10:16.160 | I think everybody would say, the closer you get to the singularity, for sure you have to include quantum mechanics.

00:10:21.300 | You just can't consistently talk about magnifying such small scales, having such enormous ruptures and curvatures and energy scales, and not include quantum mechanics.

00:10:35.080 | So you've described the brain-breaking idea that a black hole is not so much a superdense matter, as it's sometimes described, but it's more akin to, you know, a region of space-time, but even more so, just nothing.

00:10:55.080 | Yeah.

00:10:56.020 | It's nothing.

00:10:56.800 | That's the thing you seem to like to say?

00:10:59.020 | I do.

00:10:59.600 | I do like to say that black holes are no thing.

00:11:03.120 | No thing.

00:11:03.740 | Okay, so what does that mean?

00:11:05.980 | And that's what I mean, that's the more profound aspect of the black hole.

00:11:08.960 | So you asked originally, how do they form?

00:11:12.840 | And I think that even when you try to form them in messy astrophysical systems, there's still nothing, at the end of the day, left behind.

00:11:22.040 | And this was a very big surprise, even though Einstein accepted that this was a true prediction.

00:11:28.180 | He didn't think that they'd be made, and it was quite astounding that people like Oppenheimer—actually, it's probably Oppenheimer's most important theoretical work—who are thinking about nuclear physics and quantum mechanics, but in the context of these kind of utopian questions.

00:11:44.900 | Why do stars shine?

00:11:48.160 | Why is the sun radiant and hot and this amazing source of light?

00:11:52.120 | And it was people like Oppenheimer who began to ask the question, well, could stars collapse to form black holes?

00:12:00.480 | Could they become so dense that eventually not even light would escape?

00:12:07.320 | And that's why I think people think that black holes are these dense objects.

00:12:12.300 | That's often how it's described.

00:12:13.640 | But actually, what happens, these very massive stars, they're burning thermonuclear fuel.

00:12:18.120 | You know, they're earthfuls of thermonuclear fuel they're burning and emitting energy.

00:12:24.560 | And E equals mc squared energy.

00:12:26.240 | So it's fusing.

00:12:27.080 | It's a fusion bomb.

00:12:28.060 | It's a constantly going thermonuclear bomb.

00:12:30.820 | And eventually, it's going to run out of fuel.

00:12:33.740 | It's going to run out of hydrogen, helium stuff to fuse.

00:12:37.140 | It hits an iron core.

00:12:38.920 | Iron, to go past iron with fusion is actually energetically expensive.

00:12:44.280 | So it's no longer going to do that so easily.

00:12:46.920 | So suddenly, it's run out of fuel.

00:12:48.440 | And if the star is very, very, very massive, much more massive than our sun, maybe 20, 30 times the mass per sun, it'll collapse under its own weight.

00:12:56.860 | And that collapse is incredibly fast and dramatic, and it creates a shock wave.

00:13:02.200 | So that's the supernova explosion.

00:13:03.700 | So a lot of these, they rebound because once they crunch, they've reached a new critical capacity where they can reignite to higher elements, heavier elements.

00:13:15.240 | And that sets off a bomb, essentially.

00:13:17.900 | So the star explodes, helpfully, because that's why you and I are here.

00:13:23.040 | Because stars send their material back out into space, and you and I get to be made of carbon and oxygen and all this good stuff.

00:13:31.020 | We're not just hydrogen.

00:13:32.300 | So the suns do that for us.

00:13:34.840 | And then what's left sometimes ends at a neutron star, which is a very cool object, very fascinating object, super dense, but bigger than a black hole, meaning it's not compact enough to become a black hole.

00:13:50.120 | It's an actual thing.

00:13:51.260 | A neutron star is a real thing.

00:13:52.660 | It's like a giant neutron.

00:13:54.720 | Literally, electrons get jammed into the protons and make this giant nucleus and this superconducting matter.

00:14:00.140 | Very strange, amazing objects.

00:14:02.760 | But if it's heavier than that, but if it's heavier than twice the mass of the sun, it will become a black hole.

00:14:11.580 | And Oppenheimer wrote this beautiful paper in 1939 with his student saying that they believed that the end state of gravitational collapse is actually a black hole.

00:14:24.180 | This is stunning and really a visionary conclusion.

00:14:29.660 | Now, the paper is published the same day the Nazis advance on Poland.

00:14:33.740 | And so it does not get a lot of fanfare in the newspapers.

00:14:38.720 | We think there's a lot of drama today on social media.

00:14:41.580 | Imagine that.

00:14:42.500 | Like, here's a guy who predicts how actually in nature would be the formation of this most radical of object that broke even Einstein's brain,

00:14:53.020 | while one of the most evil, if not the most evil humans in history starting the first steps of a global war.

00:15:02.080 | What I also love about that lesson is how agnostic science is, because he was asking these utopian questions, as were other people of the time, about the nuclear physics and stars.

00:15:11.560 | You might know this play, Copenhagen, by Michael Frayn.

00:15:14.960 | There's this line that he attributes to Bohr.

00:15:17.220 | Bohr was the great thinker of early foundations of quantum mechanics, Danish physicist, where Bohr says to his wife,

00:15:26.420 | nobody's thought of a way to kill people using quantum mechanics.

00:15:30.360 | Now, of course, then there's the nuclear bomb.

00:15:32.960 | And what I love about this was the pressure scientists were under to do something with this nuclear physics and to enter this race over a nuclear weapon.

00:15:44.420 | But really, at the same time, 1939, really, Oppenheimer's thinking about black holes.

00:15:49.840 | There's even a small line in Chris Nolan's film.

00:15:53.080 | It's very hard to catch.

00:15:54.840 | There's a reference to it in the film where they're sort of joking,

00:15:58.240 | well, I guess nobody's going to pay attention to your paper now, you know, because of the Nazi advance on Poland.

00:16:04.120 | That's the other remarkable thing about Oppenheimer is he's also a central figure in the construction of the bomb.

00:16:09.440 | Right.

00:16:10.080 | So it's theory and experiment clashing together with the geopolitics.

00:16:14.760 | Exactly.

00:16:15.220 | So, of course, Oppenheimer, now known as the father of the atomic bomb, he talks about destroyers of worlds.

00:16:23.400 | But it's the same technology.

00:16:25.800 | And that's what I mean by science is agnostic, right?

00:16:28.260 | It's the same technology, overcoming a critical mass, igniting thermonuclear fusion.

00:16:35.200 | Eventually, there was a fission.

00:16:36.220 | The original bomb was a fission bomb.

00:16:37.840 | And fission was first shown by Lise Meitner, who showed that a certain uranium, when you bombarded it with protons,

00:16:44.200 | broke into smaller pieces that were less than the uranium, right?

00:16:48.580 | So some of that mass, that E equals mc squared energy, had escaped.

00:16:53.000 | And it was the first kind of concrete demonstration of this, Einstein's most famous equation.

00:16:58.660 | So all of this comes together.

00:17:01.000 | But the story of, they still weren't called black holes.

00:17:04.940 | This is 1939.

00:17:06.040 | And they had these very long-winded ways of describing the end state, the catastrophic end state of gravitational collapse.

00:17:13.360 | But what you have to imagine is, as this star collapses, so now, so what's the sun?

00:17:18.760 | The sun's a million and a half kilometers across.

00:17:21.960 | So imagine a star much bigger than the sun, much bigger radius.

00:17:25.760 | And it's so heavy, it collapses, it supernovas.

00:17:28.600 | What's left is still maybe 10 times the mass of the sun, just what's left in that core.

00:17:33.320 | And it continues to collapse.

00:17:35.480 | And when that reaches about 60 kilometers across, like, just imagine, 10 times the mass of the sun, city-sized.

00:17:42.120 | That is a really dense object.

00:17:44.480 | And now the black hole essentially has begun to form,

00:17:47.800 | meaning the curve in space-time is so tremendous that not even light can escape.

00:17:52.860 | The event horizon forms.

00:17:54.900 | But the event horizon is almost imprinted on the space-time.

00:17:58.740 | Because the star can't sit there in that dense state any more than it can race outward at the speed of light.

00:18:05.600 | Because even light is forced to rain inwards.

00:18:08.140 | So the star continues to fall.

00:18:10.360 | And that's the magic part.

00:18:12.000 | The star leaves the event horizon behind.

00:18:14.640 | And it continues to fall.

00:18:17.280 | And it falls into the interior of the black hole.

00:18:19.940 | Where it goes, nobody really knows.

00:18:22.760 | But it's gone from sight.

00:18:24.680 | It goes dark.

00:18:27.460 | There's this quote by John Wheeler, who's like granddaddy of American relativity.

00:18:31.800 | And he has a line that's something to the effect.

00:18:33.920 | The star, like the Cheshire cat, fades from view.

00:18:37.720 | One leaves behind, only its grin.

00:18:40.460 | The other, only its gravitational attraction.

00:18:42.900 | And he was giving a lecture.

00:18:45.800 | It's actually above Tom's Restaurant, you know, from Seinfeld near Columbia in New York.

00:18:51.660 | But there was a place, or there still is a place there, where people were giving lectures about astrophysics.

00:18:58.180 | And it's 1967.

00:18:59.660 | Wheeler is exhaustively saying this loaded term, the end state of catastrophic gravitational collapse.

00:19:07.760 | And rumor is that someone shouts from the back row, well, how about black hole?

00:19:11.840 | And apparently he then foists this term on the world.

00:19:16.760 | Wheeler had a way of doing that.

00:19:19.120 | Well, I love terms like that.

00:19:20.300 | Big bang, black hole.

00:19:22.000 | There's some, I mean, it's just pointing out the elephant in the room and calling it an elephant.

00:19:27.780 | It is a black hole.

00:19:29.060 | That's a pretty accurate and deep description.

00:19:32.660 | I just wanted to point out that the, just looking for the first time, it's a 1939 paper from Oppenheimer.

00:19:38.020 | It's like two pages, it's like three pages.

00:19:40.060 | Oh yeah, it's gorgeous.

00:19:40.780 | The simplicity of some of these, that's so gangster.

00:19:45.180 | Just revolutionize all of physics with, you know, Einstein did that multiple times in a similar year.

00:19:50.780 | When all thermonuclear sources of energy are exhausted, a sufficiently heavy star will collapse.

00:19:56.380 | That's an opener.

00:19:58.020 | Unless fission due to rotation, the radiation of mass or the blowing off of mass by radiation reduce the star's mass to orders of that of the sun, this contraction will continue indefinitely.

00:20:09.640 | And it goes on that way.

00:20:11.380 | Now, I have to say, Wheeler, who actually coins the term black hole, gives Oppenheimer quite a terrible time about this.

00:20:19.240 | He thinks he's wrong.

00:20:20.080 | And they entered what has sometimes been described as kind of a bitter, I don't know if you would actually say feud, but there were bad feelings.

00:20:30.040 | And Wheeler actually spent decades saying Oppenheimer was wrong.

00:20:35.600 | And eventually, with his computer work, that early work that Wheeler was doing with computers, when he was also trying to understand nuclear weapons, and in peacetime, found themselves returning again to these astrophysical questions, decided that actually Oppenheimer had been right.

00:20:54.400 | He thought it was too simplistic, too idealized a setup that they had used, and that if you looked at something that was more realistic and more complicated, that it just simply, it just would go away.

00:21:05.800 | And in fact, he draws the opposite conclusion.

00:21:08.100 | And there's a story that Oppenheimer was sitting outside of the auditorium when Wheeler was coming forth with his declaration that, in fact, black holes were the likely end state of gravitational collapse for very, very heavy stars.

00:21:23.140 | And when asked about it, Oppenheimer sort of said, well, I've moved on to other things.

00:21:27.940 | Because you've written in many places about the human beings behind the science.

00:21:32.200 | I have to ask you about this, about nuclear weapons, where it's the greatest of physicists coming together to create this most terrifying and powerful of a technology.

00:21:41.280 | And now I get to talk to world leaders for whom this technology is part of the tools that is used, perhaps implicitly, on the chessboard of geopolitics.

00:21:54.600 | What can you say, as a person who is a physicist and who has studied the physicists and written about the physicists, the humans behind this, about this moment in human history when physicists came together and created this weapon that's powerful enough to destroy all of human civilization?

00:22:13.400 | I think it's an excruciating moment in the history of science.

00:22:19.460 | People talk about Heisenberg, who stayed in Germany and worked for the Nazis in their own attempt to build the bomb.

00:22:30.320 | There was this kind of hopeful talk that maybe Heisenberg had intentionally derailed the nuclear weapons program.

00:22:37.900 | But I think that's been largely discredited, that he would have made the bomb, could he?

00:22:42.680 | Had he not made some really kind of simple errors in his original estimates about how much material would be required or how they would get over the energy barriers?

00:22:51.960 | And that's a terrifying thought.

00:22:56.080 | I don't know that any of us can really put ourselves in that position of imagining that we're faced with that quandary, having to take the initiative to participate in thinking of a way that quantum mechanics can kill people, and then making the bomb.

00:23:10.740 | I think overwhelmingly physicists today feel we should not continue in the proliferation of nuclear weapons.

00:23:18.920 | Very few theoretical physicists want to see this continue.

00:23:22.860 | That moment in history, the Soviet Union had incredible scientists, Nazi Germany had incredible scientists, and the United States had incredible scientists.

00:23:32.140 | And it's very easy to imagine that one of those three would have created the bomb first, not the United States.

00:23:39.920 | And how different would the world be?

00:23:42.860 | The game theory of that, I think, say it's the probability.

00:23:48.820 | That it's 33% that it was in the United States.

00:23:51.280 | If the Soviet Union had the bomb, I think they would have used it in a much more terrifying way in the European theater and maybe turn on the United States.

00:24:04.060 | And obviously with Hitler, he would have used it, I think there's no question he would have used it, to kill hundreds of millions of people.

00:24:12.920 | In the game theory version, this was the least harmful outcome.

00:24:17.100 | Yes, but there is no outcome with no bomb that any game theorist would, I think, would play.

00:24:24.720 | But I think if we just remove the geopolitics and the ideology and the evil dictators, all of those people are just scientists.

00:24:35.380 | I think they don't necessarily think about it, I think they don't necessarily think about the ideology.

00:24:38.760 | And it's a deep lesson about the connection between great science and the annoying, sometimes evil politicians that use that science for means that are either good or bad.

00:24:53.580 | And the scientists perhaps don't, boy, do they even have control of how that science is used?

00:25:00.240 | It's hard.

00:25:00.620 | They don't have control.

00:25:01.580 | Right.

00:25:02.060 | Once it's made, it's no longer scientific reasoning that dictates the use or restraint.

00:25:11.060 | But I will say that I do believe that it wasn't a 31 third down the line because America was different.

00:25:19.460 | And I think that's something we have to think about right now in this particular climate.

00:25:22.680 | So many scientists fled here.

00:25:25.180 | They fled to here.

00:25:26.860 | Americans weren't fleeing to Nazi Germany.

00:25:30.960 | They came here and they were motivated by, it's more than a patriotism, you know, it was, I mean, it was a patriotism, obviously, but it was sort of more than that.

00:25:43.220 | It was really understanding the threat of Europe, what was going on in Europe and what that life, how quickly it turned, how quickly this free spirited Berlin culture, you know,

00:25:57.160 | was suddenly in this repressive and terrifying regime.

00:26:02.200 | So I think that it was a much higher chance that it happened here in America.

00:26:07.700 | Yeah, there's something about the American system, the, you know, it's cliche to say, but the freedom, all the different individual freedoms that enable a very vibrant, at its best, a very vibrant scientific community.

00:26:19.300 | And that's really exciting.

00:26:20.380 | Absolutely.

00:26:20.880 | To scientists.

00:26:21.640 | And it's very valuable to maintain that.

00:26:24.200 | Right.

00:26:25.620 | The vibrancy of the debate, of the funding, those mechanisms.

00:26:28.960 | Absolutely.

00:26:29.640 | The world flocked here.

00:26:31.460 | And that won't be the case if we no longer have intellectual freedom.

00:26:36.380 | Yeah, there's something interesting to think about.

00:26:38.740 | The tension, the Cold War between China and the United States in the 21st century, you know, some of those same questions, some of those ideas will rise up again.

00:26:46.560 | And we want to make sure that there's a vibrant free exchange of scientific ideas.

00:26:52.520 | I believe most Nobel Prizes come from the United States, right?

00:26:56.940 | Oh, yeah.

00:26:58.080 | I don't have the number, but it's disproportionately so.

00:27:00.760 | It's disproportionately so.

00:27:01.580 | In fact, a lot of them from particle physics came from the Bronx.

00:27:07.420 | And they were European immigrants.

00:27:09.200 | How do we explain this?

00:27:10.520 | They fled Europe precisely because of the geopolitics we're describing.

00:27:14.140 | And so instead of being Nobel Prize winners from the Soviet Union or from the Eastern Bloc, they were from the Bronx.

00:27:22.040 | And that's the thing you write about and we'll return to time and time again.

00:27:25.400 | You know, science is done by humans.

00:27:27.140 | And some of those humans are fascinating.

00:27:28.960 | There's tensions.

00:27:30.040 | There's battles.

00:27:30.760 | There's some are loners.

00:27:32.400 | Some are great collaborators.

00:27:33.680 | Some are tormented.

00:27:34.900 | Some are easygoing.

00:27:36.780 | All this kind of stuff.

00:27:37.640 | And that's the beautiful thing about it.

00:27:38.840 | We forget sometimes is it's humans.

00:27:40.580 | And humans are messy and complicated and beautiful and all of that.

00:27:44.220 | Yeah.

00:27:44.720 | So what were we talking about?

00:27:47.300 | Oh.

00:27:47.640 | The stars collapsing.

00:27:48.960 | Okay.

00:27:51.100 | So can we just return to the collapse of a star that forms a black hole?

00:27:56.520 | At which point does the super dense thing become nothing if we can just like linger on this concept?

00:28:04.520 | Yeah.

00:28:04.980 | So if I were falling into a black hole and I tried really fast right as I crossed this empty region, but this demarcation, I happened to know where it was.

00:28:16.780 | I calculated because there's no line there.

00:28:18.800 | There's no sign that it's there.

00:28:21.060 | There's no signpost.

00:28:22.120 | I could emit a little light pulse and try to send it outward exactly at the event horizon.

00:28:27.860 | So it's racing outward at the speed of light.

00:28:29.760 | It can hover there because from my perspective, it's very strange.

00:28:33.820 | The space time is like a waterfall raining in and I'm being dragged in with that waterfall.

00:28:38.760 | I can't stop at the event horizon.

00:28:40.440 | It comes.

00:28:40.940 | It goes.

00:28:41.480 | It's behind me.

00:28:42.080 | It's behind me really quickly.

00:28:43.460 | That light beam can try to sit there because it's like a fish swimming against the Niagara, you know, swimming against the waterfall.

00:28:51.320 | It's like stuck there.

00:28:52.220 | But it's like stuck there.

00:28:54.640 | And so that's one way you can have a little signpost.

00:28:56.560 | You know, if you fly by, you think it's moving at the speed of light.

00:28:59.280 | It flies past you at the speed of light.

00:29:01.280 | But it's sitting right there at the event horizon.

00:29:03.140 | So you're falling back, cross the event horizon.

00:29:05.780 | Right at that point, you shoot outwards a photon.

00:29:08.420 | Yes.

00:29:09.160 | And it's just stuck there.

00:29:10.420 | It just gets stuck there.

00:29:11.440 | Now, it's very unstable.

00:29:14.180 | So the star can't sit there is the point.

00:29:16.120 | It just can't.

00:29:17.340 | So it rains inward with this waterfall.

00:29:19.720 | But from the outside, all we should ever really care about is the event horizon because I can't know what happens to it.

00:29:26.060 | It could be pure matter and antimatter thrown together, which annihilates into photons on the inside and loses all its mass into the energy of light.

00:29:34.800 | It won't matter to me because I can't know anything about what happened on the inside.

00:29:38.960 | Okay.

00:29:39.320 | Can we just like linger on this?

00:29:40.500 | So what models do we have about what happens on the inside of the black hole at that moment?

00:29:44.760 | So I guess that one of the intuitions, one of the big reminders that you're giving to us is like, hey, we know very little about what can happen on the inside of a black hole.

00:29:55.380 | And that's why we have to be careful about making.

00:29:57.980 | It's better to think about the black hole as an event horizon.

00:30:01.240 | But what can we know and what do we know about the physics of space time inside the black hole?

00:30:09.760 | I don't mind being incautious about thinking about what the math tells us.

00:30:13.540 | I'm not such an observer.

00:30:17.780 | I am very theoretical in my work.

00:30:20.420 | It's really pen on paper a lot.

00:30:21.860 | These are thought experiments that I think we can perform and contemplate.

00:30:27.020 | Whether or not we'll ever know is another question.

00:30:30.000 | So one of the most beautiful things that we suspect happens on the inside of a black hole is that space and time, in some sense, swap places.

00:30:41.220 | So while I'm on the outside of the black hole, let's say I'm in a nice, comfortable space station.

00:30:46.620 | This black hole is maybe 10 times the mass of the sun, 60 kilometers across.

00:30:51.760 | I could be 100 kilometers out.

00:30:53.340 | That's very, very close.

00:30:54.540 | Orbiting quite safely.

00:30:56.680 | No big deal.

00:30:57.800 | You know, hanging out.

00:30:59.020 | I don't bug the black hole.

00:31:01.080 | The black hole doesn't bug me.

00:31:02.620 | It won't suck me up like a vacuum or anything crazy.

00:31:04.940 | But my astronaut friend jumps in.

00:31:11.040 | As they cross the event horizon, what I'm calling space, I'm looking on the outside at this spherical shadow of the black hole cast by maybe light around it.

00:31:21.840 | It's a shadow because everything gets too close, falls in.

00:31:24.660 | It's just this contrast against a bright sky.

00:31:29.000 | I think, oh, there's a center of a sphere.

00:31:31.440 | And in the center of the sphere is the singularity.

00:31:34.240 | It's a point in space from my perspective.

00:31:36.780 | But from the perspective of the astronaut who falls in, it's actually a point in time.

00:31:41.200 | So their notions of space and time have rotated so completely that what I'm calling a direction in space towards the center of the black hole, like the center of a physical sphere, they're going to tell me what they can't tell me.

00:31:54.660 | But they're going to come to the conclusion, oh, no, that's not a location in space.

00:31:58.900 | That's a location in time.

00:32:01.800 | In other words, the singularity ends up in their future, and they can no more avoid the singularity than they can avoid time coming their way.

00:32:11.080 | So there's no shenanigans you can do once you're inside the black hole to try to skirt it, the singularity.

00:32:18.040 | You can't set yourself up in orbit around it.

00:32:20.720 | You can't try to fire rockets and stay away from it because it's in your future.

00:32:26.260 | And there's an inevitable moment when you will hit it.

00:32:28.860 | Usually for a stellar mass black hole, we think it's microseconds.

00:32:32.820 | Microseconds to get from the event horizon to the...

00:32:35.560 | To the singularity.

00:32:36.340 | To the singularity.

00:32:37.300 | Oh, boy.

00:32:37.980 | So that's describing from your astronaut friend's perspective.

00:32:44.960 | Yes, from their perspective, the singularity is in their future.

00:32:48.340 | But from your perspective, what do you see when your friend falls into the black hole and you're chilling outside and watching?

00:32:56.360 | So one way to think about this is to think that as you're approaching the black hole, the astronaut's space time is rotating relative to your space time.

00:33:11.000 | So let's say right now, my left is your right.

00:33:14.820 | We're not shocked by the fact that there's this relativity in left and right.

00:33:18.780 | It's completely understood.

00:33:19.880 | And I can perform a spatial rotation to align my left with your left.

00:33:24.700 | Right now, I've completely rotated left out.

00:33:30.400 | If I just want to draw a kind of compass diagram, not a compass diagram, but you know, at the top of maps, there's a north, south, east, west.

00:33:37.960 | But now time is up, down, and one direction of space is, let's say, east, west.

00:33:43.760 | As you approach the black hole, it's as though you're rotating in space time.

00:33:48.160 | There's one way of thinking about it.

00:33:50.640 | So what is the effect of that?

00:33:52.360 | The effect of that is as this astronaut gets closer and closer to the event horizon, part of their space is rotated into my time, and part of their time is rotated into my space.

00:34:06.100 | So in other words, their clocks seem to be less aligned with my time, and the overall effect is that their time seems to dilate.

00:34:16.180 | The spacing between ticks on the clock of their watch, let's say, on the face of their watch, is elongated, dilated, relative to mine.

00:34:28.420 | And it seems to me that their watches are running slowly, even though they were made in the same factory as mine, they were both synchronized beautifully, and they're excellent Swiss watches.

00:34:36.760 | It seems as though time is elapsing more slowly for my companion.

00:34:41.260 | And likewise, for them, it seems like mine's going really fast.

00:34:47.180 | So years could elapse in my space station.

00:34:52.340 | My plants come and go.

00:34:54.120 | They die.

00:34:54.600 | I age faster.

00:34:55.520 | I've got gray hair.

00:34:57.480 | And they're falling in, and it's been minutes in their frame of reference.

00:35:01.580 | Flowers in their little rocket ship haven't rotted.

00:35:06.460 | They don't have gray hair.

00:35:08.100 | Their biological clocks have slown down relative to ours.

00:35:12.700 | Eventually, at the event horizon, it's so extreme, it's so slow, it's as though their clocks have stopped altogether, from my point of view.

00:35:21.140 | And that's to say that it's as though their time is completely rotated into my space.

00:35:27.420 | And this is connected with the idea that inside the black hole, space and time have switched places.

00:35:33.640 | So I might see them hover there for millennia.

00:35:37.860 | Other astronauts could be born on my space station.

00:35:41.560 | Generations could be populated there watching this poor astronaut never fall in.

00:35:48.740 | So basically, time almost comes to a standstill.

00:35:53.480 | But we still, they do fall in.

00:35:56.600 | Right.

00:35:57.480 | They do fall in eventually.

00:35:58.480 | Now, that's because they have some mass of their own.

00:36:01.540 | Yeah.

00:36:02.060 | So they're not a perfectly light particle.

00:36:04.360 | And so they deform the event horizon a little bit.

00:36:09.160 | You will actually see the event horizon bobble and absorb the astronaut.

00:36:14.540 | So in some finite time, the astronaut will actually fall in.

00:36:18.100 | So it's like this weird space-time bubble that we have around us.

00:36:22.100 | And then there's a very big space-time curvature bubble thing from the black hole.

00:36:28.540 | And there's a nice swirly type situation going on.

00:36:31.880 | That's how you get sucked up.

00:36:33.120 | Yeah.

00:36:33.580 | So if you're a perfect, like, infinitely small particle, you would just be-

00:36:37.880 | Take longer and longer.

00:36:38.860 | And probably just be stuck there or something.

00:36:41.720 | But no, there's quantum mechanics.

00:36:42.880 | Mm-hmm.

00:36:43.300 | Eventually, you'll fall in.

00:36:44.620 | Any perturbation will only go one way.

00:36:46.980 | It's unstable in one direction.

00:36:48.580 | In one direction.

00:36:49.600 | In one direction only.

00:36:50.000 | But it's really important to remember that from the point of view of the astronaut,

00:36:57.280 | not much time has passed at all.

00:36:58.780 | You just sail right across as far as you're concerned.

00:37:02.120 | And nothing dramatic happens there.

00:37:03.940 | You might not even realize you've come to the event horizon.

00:37:06.960 | You might not even realize you've crossed the event horizon.

00:37:09.920 | Because there's nothing there.

00:37:11.760 | Right?

00:37:12.900 | This is an empty region of space-time.

00:37:15.100 | There's no marker to tell you you've reached this very dangerous point of no return.

00:37:20.460 | You can fire your rockets like hell when you're on the outside.

00:37:24.340 | And maybe even escape.

00:37:25.400 | Right?

00:37:26.200 | But once you get to that point, there's no amount of energy.

00:37:30.220 | All the energy in the universe will not save you from this demise.

00:37:35.480 | You know, there's different size black holes.

00:37:38.320 | Mm-hmm.

00:37:39.160 | And maybe can we talk about the experience that you have falling into a black hole,

00:37:42.640 | depending on what the size of the black hole is?

00:37:44.760 | Yeah.

00:37:45.380 | Because, as I understand, the bigger it is, the less drastic the experience of falling into it.

00:37:55.960 | Yeah.

00:37:56.180 | That might surprise people.

00:37:57.640 | Yeah.

00:37:58.080 | The bigger it is, the less noticeable it is that you've crossed the event horizon.

00:38:03.720 | One way to think about it is curvature is less noticeable the bigger it is.

00:38:09.660 | So if I'm standing on a basketball, I'm very aware I'm balancing on a curved surface.

00:38:15.220 | My two feet are in different locations, and I really notice.

00:38:18.700 | But on the Earth, you actually have to be kind of clever to deduce that the Earth is curved.

00:38:23.020 | The bigger the planet, the less you're going to notice the curvature, the global curvature.

00:38:29.560 | And it's the same thing with a black hole.

00:38:31.340 | A huge, huge black hole.

00:38:32.720 | It just kind of feels like just flat.

00:38:35.580 | You don't really notice.

00:38:36.840 | I'm trying to figure out how the physics, because if you don't notice.

00:38:39.880 | And there's nothing there.

00:38:41.160 | But the physics is weird.

00:38:42.900 | In your frame of reference.

00:38:45.240 | No.

00:38:46.980 | Well, so another cool thing.

00:38:48.760 | So I'd like to dispel myths.

00:38:50.340 | Yeah.

00:38:51.920 | Do you need a minute?

00:38:53.540 | You're holding your head.

00:38:56.560 | There's a sense like you should be able to know when you're inside of a black hole,

00:39:00.020 | when you've crossed the event horizon.

00:39:02.100 | But no, from your frame of reference, you might not be able to know.

00:39:06.340 | Yeah.

00:39:07.160 | At first, at least, you might not realize what's happened.

00:39:10.120 | There are some hints.

00:39:11.960 | For instance, black holes are dark from the outside, but they're not necessarily dark on the inside.

00:39:17.860 | So this is a kind of fascinating that your experience could be that it's quite bright inside the black hole,

00:39:26.880 | because all the light from the galaxy can be shining in behind you.

00:39:31.500 | And it's focusing down, because you're all approaching this really focused region in the interior.

00:39:37.300 | And so you actually see a bright, white flash of light as you approach the singularity.

00:39:43.140 | You know, I kind of, I joke that it's a, you know, it's like a near-death experience.

00:39:48.200 | We see the light at the end of the tunnel.

00:39:49.800 | So you would see millennia pass on Earth.

00:39:52.200 | You could see the evolution of the entire galaxy, you know, one big bright flash of light.

00:39:58.140 | So it's like a near-death experience, but it's definitely a total death experience.

00:40:01.520 | It goes pretty fast.

00:40:02.500 | But you looking out, you looking out, everything's going super fast.

00:40:07.500 | Yeah.

00:40:07.940 | The clocks on the Earth, on the space station, seem to be progressing very rapidly relative to yours.

00:40:15.940 | The light can catch up to you, and you get this bright beam of light as you see the evolution of the galaxy unfold.

00:40:23.500 | And I mean, it sort of depends on the size of the black hole and how long you have to hang around.

00:40:30.300 | The bigger the black hole, the longer it takes you to expire in the center.

00:40:35.120 | Obviously, the human sensory system, we're not able to process that information correctly.

00:40:41.100 | Right.

00:40:41.560 | It would be a microsecond in a, right, that would be too fast.

00:40:44.160 | Yeah, but it would be, wow, it would be so cool to get that information.

00:40:48.360 | But a big black hole, you could actually, you know, hang around for some months.

00:40:52.540 | So, yeah, what's, how are small black holes or just supermassive black holes formed?

00:41:00.560 | Just so people can kind of load that in.

00:41:02.700 | Are they all, is it always a star?

00:41:06.020 | No.

00:41:07.180 | So, this is also why it's important to think of black holes more abstractly.

00:41:12.680 | They are something very profound in the universe, and there are probably multiple ways to make black holes.

00:41:18.840 | Making them with stars is most plentiful.

00:41:22.860 | There could be hundreds of millions, maybe even a billion black holes in our Milky Way galaxy alone.

00:41:28.880 | That many stars, it's only about 1% of stars that will end their lives in a death state that is a black hole.

00:41:37.060 | But we now see, and this was really quite a surprise, that there are supermassive black holes.

00:41:43.280 | There are billions or even hundreds of billions of times the mass of the sun.

00:41:49.140 | And millions to tens of billions, maybe even hundreds of billions.

00:41:54.560 | So, extremely massive.

00:41:56.020 | We don't think that the universe has had enough time to make them from stars that just merge.

00:42:02.620 | We know that two black holes can merge and make a bigger black hole, and then those can merge and make a bigger black hole.

00:42:09.000 | We don't think there's been enough time for that.

00:42:11.080 | So, it's suspected that they're formed very early, maybe even a few hundred million years after the Big Bang, and that they're formed directly by collapsing out of primordial stuff.

00:42:24.740 | That there's a direct collapse right into the black hole.

00:42:28.760 | So, like, in the very early universe, these are primordial black holes from the stars, not quite.

00:42:36.940 | Wait, how do you get from that soup black holes right away?

00:42:41.160 | Right. So, it's odd, but it's weirdly easier to make a big black hole out of something that's just the density of air, if it's really, really as big as what we're talking about.

00:42:52.480 | So, in some sense, if they're just allowed to directly collapse very early in the universe's history, they can do that more easily.

00:43:00.760 | And it's so much so that we think that there's one of these supermassive black holes in the center of every galaxy.

00:43:07.260 | So, they're not rare, and we know where they are.

00:43:10.660 | They're in the nuclei of galaxies.

00:43:12.200 | So, they're bound to the very early formation of entire galaxies in a really surprising and deeply connected way.

00:43:21.440 | I wonder if the, like, the chicken or the egg, is it, like, how critical, how essential are the supermassive black holes to the formation of galaxies?

00:43:30.680 | Yeah. I mean, it's ongoing, right? It's ongoing. Which came first? The black hole or the galaxy?

00:43:36.860 | Probably big early stars, which were just made out of hydrogen and helium from the Big Bang.

00:43:46.020 | There wasn't anything else, not much of anything else.

00:43:48.620 | Those early stars were forming, and then maybe the black holes and kind of the galaxies were like these gassy clouds around them.

00:43:56.280 | But there's probably a deep relationship between the black hole-powering jets,

00:44:02.820 | these jets blowing material out of the galaxy that shaped galaxies, maybe kind of curbed their growth.

00:44:12.680 | And so, I think the mechanisms are still ongoing, attempts to understand exactly the ordering of these things.

00:44:21.560 | Can we get back to space-time?

00:44:24.160 | Just going back to the beginning of the 20th century, how do you imagine space-time?

00:44:28.000 | How do we, as human beings, are supposed to visualize and think about space-time,

00:44:31.460 | where, you know, time is just another dimension in this 4D space that combines space and time?

00:44:38.060 | Because we've been talking about morphing in all kinds of different ways, the curvature of space-time.

00:44:42.020 | Like, how do you, how are we supposed to conceive of it?

00:44:45.180 | How do you think of it?

00:44:46.720 | Yeah.

00:44:46.980 | And time is just another dimension?

00:44:48.600 | There are different ways we can think about it.

00:44:51.300 | We can imagine drawing a map of space and treating time as another direction in that map.

00:45:00.120 | But we're limited because, as three-dimensional beings, we can't really draw four dimensions,

00:45:06.160 | which is what I'd require.

00:45:07.280 | Three-spatial, because I'm pretty sure there's at least three.

00:45:10.460 | I think there's probably more.

00:45:11.840 | But I'm happy just talking about the large dimensions.

00:45:15.720 | The three we see up-down, right?

00:45:19.100 | East-west, north-south, three-spatial dimensions.

00:45:23.920 | And time is the fourth.

00:45:25.700 | Nobody can really visualize it.

00:45:30.600 | But we know mathematically how to unpack it on paper.

00:45:34.000 | I can mathematically suppress one of the spatial dimensions, and then I can draw it pretty well.

00:45:40.180 | Now, the problem is that we'd call it a Euclidean space-time.

00:45:44.580 | Euclidean space-time is when all the dimensions are orthogonal and are treated equally.

00:45:49.560 | Time is not another Euclidean dimension.

00:45:52.620 | It's actually a Minkowski in space-time.

00:45:54.800 | But it means that the space-time, we're misrepresenting it when we draw it, but we're misrepresenting it in a way that we deeply understand.

00:46:04.060 | I can give you an example.

00:46:05.920 | The Earth, I can project onto a flat sheet of paper.

00:46:08.840 | I am now misrepresenting a map of the Earth.

00:46:12.460 | And I know that.

00:46:13.440 | But I understand the rules for how to add distances on this misrepresentation, because the Earth is not a flat sheet of paper.

00:46:20.320 | It's a sphere.

00:46:21.820 | And as long as I understand the rules for how I get from the North Pole to the South Pole, that I'm moving along really a great arc, and I understand that the distance is not the distance I would measure on a flat sheet of paper, then I can do a really great job with a map and understanding the rules of addition, multiplication, and the geometries, not the geometry of a flat sheet of paper.

00:46:43.680 | I can do the same thing with space-time.

00:46:45.400 | I can draw it on a flat sheet of paper, but I know that it's not actually a flat Euclidean space.

00:46:50.600 | And so my rules for measuring distances are different than the rules I would use that, for instance, Cartesian rules of geometry.

00:47:00.380 | I would know to use the correct rules for Minkowski space-time.

00:47:03.980 | And that will allow me to calculate how long time has elapsed, which is now a kind of a length, a space-time length on my map, between two relative observers.

00:47:20.280 | And I will get the correct answer, but only if I use these different rules.

00:47:24.760 | So then what does, according to general relativity, does objects with mass do to the space-time?

00:47:32.760 | Right, exactly.

00:47:34.260 | So Einstein struggled for this completely general theory, not a specific solution like a black hole or an expanding space-time or galaxies make lenses.

00:47:45.880 | Those are all solutions.

00:47:47.360 | That's why what he did was so enormous.

00:47:49.520 | It's an entire paradigm that says, over here is matter and energy.

00:47:55.020 | I'm going to call that the right-hand side of the equation.

00:47:59.280 | Everything on the right-hand side of Einstein's equations is how matter and energy are distributed in space-time.

00:48:05.160 | On the left-hand side tells you how space and time deform in response to that matter and energy.

00:48:12.580 | And it can be impossible to solve some of those equations.

00:48:16.760 | What was so amazing about what Schwarzschild did is he found this very elegant, simple solution within like a month of reading this final formulation.

00:48:27.280 | But Einstein didn't go through and try to find all the solutions.

00:48:29.740 | He sort of gave it to us, right?

00:48:32.160 | He shared this.

00:48:33.600 | And then lots of people since have been scrambling to try to, ah, I can predict the curvature of the space-time if I tell you how the matter and energy is laid out.

00:48:43.260 | If it's all compact in a spherical system like a sun or even a black hole, I can understand the curves in the space-time around it.

00:48:50.840 | I can solve for the shape of the space-time.

00:48:54.120 | I can also say, well, what if the universe is full of gas or light and it's all kind of uniform everywhere and I'll find a different, equally surprising solution, which is that the universe would expand.

00:49:05.660 | In response to that, that it's not static, that the distances between galaxies would grow.

00:49:11.780 | This was a huge surprise to Einstein.

00:49:13.520 | So all of these consequences of his theory, you know, came with revelations.

00:49:20.660 | That were not at all obvious when he first wrote down the general theory.

00:49:26.920 | And he was afraid to take the consequences of that theory seriously, which is a-

00:49:31.880 | Often.

00:49:31.940 | The theory itself in its scope and grandeur and power is scary, so I can understand.

00:49:39.620 | Then there's, you know, the edges of the theory where it falls apart, the consequences of the theory that are extreme.

00:49:46.120 | It's hard to take seriously.

00:49:47.320 | So you can sort of empathize.

00:49:49.920 | Yeah.

00:49:50.120 | He very much resisted the expansion.

00:49:52.020 | So if you think about 1905, when he's writing these sequence of unbelievable papers as a 25-year-old who can't get a job, you know, as a physicist, and he writes all of these remarkable papers on relativity and quantum mechanics.

00:50:06.700 | And then even in 1915-16, he does not know that there are other galaxies out there.

00:50:11.960 | This just was not known.

00:50:14.160 | People had mused about it.

00:50:16.160 | There were these kind of smudges on the sky that people contemplated.

00:50:21.900 | What if there are other island universes?

00:50:23.500 | You know, going back to Kant, thought about this.

00:50:26.100 | But it wasn't until Hubble, it really wasn't until the late 20s, that it's confirmed that there are other galaxies.

00:50:33.200 | Wow.

00:50:34.360 | Yeah.

00:50:34.960 | He didn't, obviously, there's so much we think of now that he didn't think of.

00:50:41.620 | So there's no Big Bang static universe.

00:50:45.200 | But these are all connected.

00:50:46.760 | Wow.

00:50:47.940 | Yeah.

00:50:48.700 | So he's operating on very little information.

00:50:52.380 | Very little information.

00:50:53.780 | That's absolutely true.

00:50:55.420 | Actually, one of the things I like to point out is the idea of relativity was foisted on people in this kind of cultural way.

00:51:03.460 | But there's many ways in which you could call it a theory of absolutism.

00:51:08.100 | And the way Einstein got there with so little information is by adhering to certain very strict absolutes, like the absolute limit of the speed of light and the absolute constancy of the speed of light, which was completely bizarre when it was first discovered, really.

00:51:30.420 | That was observed through experiments trying to figure out what would the relative speed of light be.

00:51:38.480 | It's the only, really, only massless particles have this property, that they have an absolute speed.

00:51:43.500 | And if you think about it, it's incredibly strange.

00:51:45.140 | Yeah, it's really strange.

00:51:46.400 | Incredibly strange.

00:51:47.080 | And so from a theoretical perspective, he takes that seriously.

00:51:52.320 | He takes it very seriously.

00:51:54.100 | And everyone else is trying to come up with models to make it go away, to make the speed of light be a little bit more reasonable, like everything else in the universe.

00:52:02.500 | You know, if I run at a car, two cars coming at each other, they're coming at each other faster than if one of them stops.

00:52:08.780 | It's really a basic observation of reality, right?

00:52:11.640 | Here, this is saying that if I'm racing at a light beam and you're standing still relative to the source, we'll measure the same exact speed of light.

00:52:22.320 | Very strange.

00:52:23.980 | And he gets to relativity by saying, well, what's speed?

00:52:27.000 | Speed is distance, it's space, over time.

00:52:31.260 | It's how far you travel, it's the space you travel, in a certain duration of time.

00:52:37.040 | And he said, well, I bet something must be wrong then with space and time.

00:52:40.800 | So this is an enormous leap.

00:52:42.880 | He's willing to give up the absolute character of space and time in favor of keeping the speed of light constant.

00:52:51.860 | How was he able to intuit a world of curved space-time?

00:52:59.420 | I think it's like one of the most special leaps in human history, right?

00:53:06.280 | It's amazing.

00:53:07.480 | Like it's very, very, very difficult to make that kind of leap.

00:53:12.440 | I'll tell you, it took me, I think, a long time to, I can't say this is how he got there exactly.

00:53:19.100 | It's not as though I studied the historical accounts or his description of his internal states.

00:53:27.220 | This is more having learned the subject, how I try to tell people how to get there in a few short steps.

00:53:35.860 | One is to start with the equivalence principle, which he called the happiest thought of his life.

00:53:40.400 | And the equivalence principle comes pretty early on in his thinking.

00:53:46.560 | And it starts with something like this.

00:53:49.940 | Like right now, I think I'm feeling gravity because I'm sitting in this chair and I feel the pressure of the chair and it's stopping me from falling.

00:53:57.260 | And I lie down in a bed and I feel heavy on the bed and I think of that as gravity.

00:54:02.100 | And Einstein has a beautiful ability to remove all of these extraneous factors, including atoms.

00:54:10.340 | So let's imagine instead that you're in an elevator and you feel heavy on your feet because the floor of the elevator is resisting your fall.

00:54:19.920 | But I want to remove the elevator.

00:54:21.640 | What does the elevator have to do with fundamental properties of gravity?

00:54:25.000 | So I cut the cable.

00:54:26.080 | Now I'm falling, but the elevator is falling at the same rate as me.

00:54:31.460 | So now I'm floating in the elevator.

00:54:34.300 | And if this happened to me, if I woke up in this state of falling or floating in the elevator, I might not know if I was in empty space, just floating.

00:54:44.120 | Or if I was falling around the earth.

00:54:47.120 | There would actually, they're equivalent situations.

00:54:50.100 | I would not be able to tell the difference.

00:54:52.040 | I'm actually, when I get rid of the elevator in this way by cutting the cable, I'm actually experiencing weightlessness.

00:55:00.460 | And that weightlessness is the purest experience of gravity.

00:55:04.760 | And so this idea of falling is actually fundamental.

00:55:10.680 | It's how we talk about it all the time.

00:55:12.300 | The earth is in a free fall around the sun.

00:55:15.660 | It's actually falling.

00:55:16.960 | It's not firing engines.

00:55:18.840 | It's just falling all the time, but it's just cruising so fast.

00:55:22.480 | So actually, yeah.

00:55:23.440 | Oh, God.

00:55:23.820 | You said so many profound things.

00:55:25.060 | So one of them is really one of the ways to experience space-time is to be falling.

00:55:32.700 | To be falling.

00:55:33.420 | That is the purest experience of gravity.

00:55:35.580 | The experience of gravity, unfettered, uninterrupted by atoms, is weightlessness.

00:55:43.360 | That observation, no, it has an unhappy ending, the elevator story, because of atoms again.

00:55:49.460 | That's the fault of the atoms in your body interacting electromagnetically with the crust of the earth or the bottom of the building or whatever it is.

00:55:57.820 | But this period of free fall, so the first observation is that that is the purest experience of gravity.

00:56:04.420 | Now I can convince you that things follow along curved paths, because I could take, you know, a pen, and if I throw it, we both know it's going to follow an arc, and it's going to follow an arc until atoms interfere again and it hits the ground.

00:56:19.520 | But while it's in free fall, experiencing gravity at its purest, what the Einsteinian description would say is it is following the natural curve in spacetime inscribed by the earth.

00:56:34.480 | So the earth's mass and shape curves the paths in space, and then those curvatures tell you how to fall, the paths along which you should fall when you're falling freely.

00:56:48.400 | And so the earth has found itself on a free fall that happens to be a closed circle, but it's actually falling.

00:56:57.560 | The International Space Station uses this principle all the time.

00:57:00.240 | They get the space station up there, and then they turn off the engines.

00:57:03.400 | Can you imagine how expensive it would be if they had to fuel that thing at all times, right?

00:57:07.280 | They turn off the engines.

00:57:08.480 | They're just falling.

00:57:09.860 | Yeah, they're falling.

00:57:11.080 | And they're not that far up.

00:57:12.760 | There are certainly people sometimes say, oh, they're so far away, they don't feel gravity.

00:57:17.620 | Oh, absolutely.

00:57:18.360 | If you stopped the space station, it's going like 17,500 miles an hour, something like that.

00:57:25.360 | If you were to stop that, it would drop like a stone right to the earth.

00:57:30.780 | So they're in a state of constant free fall, and they're falling along a curved path.

00:57:35.440 | And that curved path is a result of curving space-time.

00:57:39.040 | And that particular curved path is calculated in such a way that it curves onto itself, so you're orbiting.

00:57:45.200 | Right, so it has to be cruising at a certain speed, so once you get it at that cruising speed, you turn off the engines.

00:57:51.820 | But yeah, to be able to visualize at the beginning of the 20th century, that free-falling in curved space-time.

00:58:04.980 | Boy, the human mind is capable of things.

00:58:09.040 | Some of that is constructing thought experiments that collide with our understanding of reality.

00:58:17.840 | Maybe in the collisions and the contradictions, you try to think of extreme thought experiments that exacerbate that contradiction and see like, okay, what is actually—is there another model that can incorporate this?

00:58:32.740 | But to be able to do that, I mean, it's kind of inspiring because, you know, there's probably another general relativity out there.

00:58:40.560 | Yeah.

00:58:41.120 | In all—not just in physics, in all lines of work, in all scientific pursuits.

00:58:47.700 | There's certain theories where you're like, okay, I just explained like a big elephant in the room here that everybody just kind of didn't even think about.

00:58:58.340 | Like, there could be—for stuff we know about in physics, there could be stuff like that for the origin of life on Earth.

00:59:06.000 | Yeah.

00:59:06.480 | Everyone's like, yeah, okay.

00:59:07.960 | Everyone's like, in polite company, it's like, yeah, yeah, yeah, yeah.

00:59:11.660 | Somehow, it started.

00:59:14.180 | Right.

00:59:15.720 | Nobody knows.

00:59:16.500 | I find it wild that that's so elusive.

00:59:18.540 | Yeah, it's strange.

00:59:20.320 | In the lab, you can't replicate—

00:59:21.340 | It's strange that it's so elusive.

00:59:22.240 | I think it's a general relativity thing.

00:59:23.700 | There's going to be something that's going to involve aliens and wormholes and dimensions that we don't quite understand or some field that's bigger than, like—it's possible, maybe not.

00:59:36.820 | It's possible that it has—it's a field that is different, that will feel fundamentally different from chemistry and biology.

00:59:45.500 | It'll be maybe through physics.

00:59:47.640 | Again, maybe the key to the origin of life is in physics.

00:59:50.740 | And the same there, it's like a weird neighbor, it's consciousness.

00:59:54.780 | It's like, all right.

00:59:56.580 | A weird neighbor, yeah.

00:59:57.540 | It's like, okay, so we all know that life started on Earth somehow.

01:00:02.260 | Nobody knows how.

01:00:05.280 | We all know that we're conscious.

01:00:07.640 | We have a subjective experience of things.

01:00:10.240 | Nobody understands that.

01:00:11.820 | Right.

01:00:13.260 | That people have ideas and so on.

01:00:14.740 | Right.

01:00:14.960 | But it's such a dark, sort of—we're entering a dark room where a bunch of people are whispering about, like, hey, what's in this room?

01:00:23.260 | But nobody has an effing clue.

01:00:26.940 | And then somebody comes along with a general relativity kind of conception where, like, it reconceives everything.

01:00:33.100 | And you're like, ah.

01:00:34.560 | It's like a watershed moment.

01:00:36.360 | Yeah.

01:00:36.660 | Yeah.

01:00:37.000 | Yeah.

01:00:37.900 | It's there.

01:00:38.480 | And until—

01:00:39.100 | It's there.

01:00:39.440 | We're living in a time until that theory comes along.

01:00:43.220 | It would be obvious in retrospect, but right now we're—

01:00:47.260 | Right.

01:00:47.560 | Well, this—it was obvious to no one that space-time was curved, but even Newton understood something wasn't right.

01:00:57.440 | So he knew there was something missing, and I think that's always fascinating when we're in a situation where we're pressure testing our own ideas.

01:01:06.800 | He did something remarkable, Newton did, with his theory of gravity.

01:01:11.460 | Just understanding that the same phenomenon was at work with the Earth around the sun as the apple falling from the tree, that's insane.

01:01:19.500 | That's a huge leap.

01:01:21.480 | Understanding that mass, inertial mass, what makes something hard to push around, is the same thing that feels gravity, at least in the Newtonian picture, in that simple way.

01:01:30.940 | Unbelievable leap.

01:01:32.860 | Absolutely genius.

01:01:34.580 | But he didn't like that the apple fell from the tree, even though the Earth wasn't touching it.

01:01:41.000 | Yeah, the action at a distance thing.

01:01:43.140 | The action at a distance thing.

01:01:44.640 | That is weird, too.

01:01:45.880 | Well, but—

01:01:46.420 | That is a really weird one.

01:01:47.960 | It's really weird.

01:01:48.940 | But, see, Einstein solves that.

01:01:50.800 | Relativity solves that.

01:01:52.280 | Because it says, the Earth created the curve in space.

01:01:57.980 | The apple wants to fall freely along it.

01:02:00.660 | The problem is the tree's in the way.

01:02:02.880 | And the tree's the problem.

01:02:04.900 | The tree's actually accelerating the apple.

01:02:07.300 | It's keeping it away from its natural state of weightlessness in a gravitational field.

01:02:12.720 | And as soon as the tree lets go of it, the apple will simply fall along the curve that exists.

01:02:17.220 | I would love it if somebody went back to Newton's time.

01:02:21.040 | And told him all this?

01:02:22.400 | Probably some hippie would be like, gravity is just curvature in space-time, man.

01:02:29.680 | I wonder if he would be able to—I don't think there's—you know, every idea has its time.

01:02:34.240 | He might not even be able to load that in.

01:02:38.600 | I mean, sometimes even the greatest geniuses, I mean, you can't—

01:02:44.480 | It's too out of context.

01:02:46.660 | You need to be standing on the shoulders of giants, and on the shoulders of those giants, and so on.

01:02:51.680 | I heard that Newton used that as an unkind remark to his competitor, Hook.

01:02:56.820 | Oh, no.

01:02:57.880 | The people talk shit even back then.

01:03:00.500 | Yeah, trash talking.

01:03:01.700 | It's one of the hilarious things about humans in general, but scientists do, like, these huge minds.

01:03:10.660 | There's these moments in history where you'll see this in universities, but everywhere else, too.

01:03:18.040 | Like, you have gigantic minds, obviously also coupled with everybody has an ego.

01:03:23.980 | And, like, sometimes it's just the same soap opera that played out amongst humans everywhere else.

01:03:30.280 | And so you're thinking about the biggest cosmological objects and forces and ideas, and you're still, like, jealous.

01:03:38.780 | Right.

01:03:39.540 | I know.

01:03:40.460 | It's fascinating.

01:03:41.360 | This is bigger than my office.

01:03:42.620 | I know.

01:03:43.080 | This chair, this—or maybe you got married to this person that I was always in love with.

01:03:51.460 | Right.

01:03:51.740 | There's a betrayal of something.

01:03:52.840 | The one woman in the department.

01:03:54.120 | Yeah, the one woman in the department.

01:03:55.620 | Yeah.

01:03:56.600 | And it's just—I mean, but that is also the fuel of innovation, that jealousy, that tension.

01:04:01.840 | Well, you know the expression, I'm sure.

01:04:04.620 | The battles are so bitter in academia because the stakes are so low.

01:04:07.720 | That's a beautiful way to phrase it.

01:04:10.440 | But also, like, we shouldn't forget, I mean, that I love seeing that even in academia because it's humanity.

01:04:17.620 | The silliness, it's—there is a degree to academia where the reason you're able to think about some of these grand ideas is because you still allow yourself to be childlike.

01:04:28.880 | Oh, yeah.

01:04:29.340 | There's a childlike nature to be asked a big question.

01:04:31.900 | Oh, yeah.

01:04:32.600 | But children can also be like—

01:04:34.480 | Children.

01:04:35.200 | Children.

01:04:36.640 | So, like, you don't—I think when in an incorporate context and maybe the world gets—forces you to behave, you're supposed to be a certain kind of way.

01:04:46.540 | There's some aspects and it's a really beautiful aspect to preserve and to celebrate in academia is, like, you're just allowed to be childlike in your curiosity and your exploration.

01:04:59.180 | You're just exploring, asking the biggest questions.

01:05:02.960 | The best scientists I know often ask the simplest questions.

01:05:06.980 | They're really—first of all, there's probably some confidence there.

01:05:13.180 | But also, they're never going to lie to themselves that they understand something that they don't understand.

01:05:20.360 | So, even this idea that Newton didn't understand the apple falling from the tree, he—had he lived another couple hundred of years, he would have invented relativity.

01:05:30.320 | Because he never would have lied to himself that he understood it.

01:05:33.260 | He would have kept asking this very simple question.

01:05:37.340 | And I think that there is this childlike beauty to that.

01:05:40.980 | Absolutely.

01:05:41.540 | Yeah, just some of the topics—I don't know why I'm stuck to those two topics of origin of life and consciousness.

01:05:47.080 | I'll talk about those.

01:05:48.500 | Some of the most brilliant people I know are—just like with Newton and Einstein, they're stuck on that.

01:05:54.660 | This doesn't make sense.

01:05:55.580 | I know a bunch of brilliant biologists, physicists, chemists that are thinking about the origin of life.

01:06:00.400 | They're like, this doesn't—I know how evolution works.

01:06:04.240 | I know how the biological systems work, how genetic information propagates.

01:06:08.680 | But this part, the singularity at the beginning doesn't make sense.

01:06:12.140 | We don't understand.

01:06:13.540 | We can't create it in a lab.

01:06:15.220 | They're bothered—every single day, they're bothered by it.

01:06:19.240 | And that being bothered by that tension, by that gap in knowledge is—yeah, that's the catalyst.

01:06:25.580 | That's the fuel for the—

01:06:28.360 | Discovery.

01:06:29.080 | For the discovery.

01:06:30.160 | Yeah, absolutely.

01:06:31.220 | The discovery is going to come because somebody couldn't sleep at night and couldn't rest.

01:06:36.080 | So in that way, I think black holes are a kind of portal into some of the biggest mysteries of our universe.

01:06:43.480 | So it is a—it's a good terrain on which to explore these ideas.

01:06:46.820 | So can you speak about some of the mysteries that the black holes present us with?

01:06:52.900 | Yeah, I think it's important to separate the idea that there are these astrophysical states that become black holes from being synonymous with black holes.

01:07:05.500 | Because black holes are kind of this larger idea.

01:07:07.780 | And they might have been made primordially when the Big Bang happened.

01:07:14.160 | And there's something flawless about black holes that makes them fundamental, unlike anything else.

01:07:24.140 | So they're flawless in the sense that you can completely understand a black hole by looking at just its charge, electric charge, its mass, and its spin.

01:07:33.420 | And every black hole with that charge, mass, and spin is identical to every other black hole.

01:07:39.660 | You can't be like, oh, that one's mine.

01:07:41.040 | I recognize it.

01:07:42.680 | It has this little feature, and that's how I know it's mine.

01:07:45.100 | They're featureless.

01:07:46.520 | You try to put Mount Everest on a black hole, and it will shake it off in these gravitational waves.

01:07:53.440 | It will radiate away this imperfection until it settles down to be a perfect black hole again.

01:08:00.840 | So there's something about them that is unlike, and another reason why I don't like to call them objects in a traditional sense, unlike anything else in the universe that's macroscopic.

01:08:10.720 | It's kind of a little bit more like a fundamental particle.

01:08:13.960 | So an electron is described by a certain short list of properties, charge, mass, spin, maybe some other quantum numbers.

01:08:22.280 | That's what it means to be an electron.

01:08:26.080 | There's no electron that's a little bit different.

01:08:28.300 | You can't recognize your electron.

01:08:30.060 | They're all identical in that sense.

01:08:33.420 | And so in some very abstract way, black holes share something in common with microscopic fundamental particles.

01:08:42.200 | And so what they tell us about the fundamental laws of physics can be very profound.

01:08:52.080 | And it's why even theoretical physicists, mathematical physicists, not just astronomers who use telescopes, they rely on the black hole as a terrain to perform their thought experiments.

01:09:07.320 | And it's because there's something fundamental about them.

01:09:10.720 | Yeah.

01:09:11.700 | General relativity means quantum mechanics, means singularity.

01:09:15.180 | And it happens there.

01:09:15.820 | And sadly, heartbreakingly so, it's out of reach for experiment at this moment.

01:09:21.600 | But it's within reach for theoretical things.

01:09:24.460 | It's in reach for thought experiments.

01:09:26.920 | For thought experiments.

01:09:27.700 | Which are quite beautiful.

01:09:29.460 | Well, on that topic, I have to ask you about the paradox, the information paradox of black holes.

01:09:35.840 | What is it?

01:09:36.400 | So this is what catapulted Hawking's fame.

01:09:40.620 | When he was a young researcher, he was thinking about black holes and wanted to just add a little smidge of quantum mechanics.

01:09:50.200 | Just a little smidge.

01:09:51.500 | You know, I wasn't going for full-blown quantum gravity.

01:09:55.040 | But kind of just asking, well, what if I allowed this nothing, this vacuum, this empty space around the event horizon?

01:10:03.740 | Star's gone.

01:10:05.500 | There's nothing there.

01:10:06.140 | What if I allowed it to possess sort of ordinary quantum properties?

01:10:10.040 | Just a little tiny bit.

01:10:11.140 | You know, nothing dramatic.

01:10:12.100 | Don't go crazy.

01:10:14.000 | You know.

01:10:15.360 | And one of the properties of the vacuum that is intriguing is this idea that you can never see the vacuum's actually completely empty.

01:10:24.980 | We talked about Heisenberg.

01:10:26.740 | You know, the Heisenberg uncertainty principle really kicked off a lot of quantum mechanical thinking.

01:10:30.780 | It says that you can never exactly know a particle's position simultaneously with its motion, with its momentum.

01:10:38.420 | You can know one or the other pretty precisely, but not both precisely.

01:10:42.760 | And the uncertainty isn't a lack of ability that we'll technologically overcome.

01:10:47.160 | It's foundational.

01:10:48.340 | It says that there's, in some sense, when it's in a precise location, it is fundamentally no longer in a precise motion.

01:10:55.020 | And that uncertainty principle means I can't precisely say a particle is exactly here, but it also means I can't say it's not.

01:11:02.720 | Okay.

01:11:04.020 | And so it led to this idea that what do I mean by a vacuum?

01:11:08.420 | Because I can't 100% precisely know.

01:11:12.380 | In fact, it's not really meaningful to say that there's zero particles here.

01:11:16.860 | And so what you can say, however, is you can say, well, maybe particles kind of froth around in this seething quantum sea of the vacuum.

01:11:28.240 | Maybe two particles come into existence and they're entangled in such a way that they cancel out each other's properties.

01:11:35.460 | So they have the properties of the vacuum.

01:11:38.220 | You know, they don't destroy the kind of properties of the vacuum because they cancel out each other's spin, maybe, each other's charge, maybe, things like that.

01:11:47.080 | But they kind of froth around.

01:11:48.800 | They come, they go, they come, they go.

01:11:51.520 | And that's what we really think is the best that empty space can do in a quantum mechanical universe.

01:11:56.580 | Now, if you add an event horizon, which, as we said, is really fundamentally what a black hole is, that's the most important feature of a black hole.

01:12:06.380 | The event horizon, if the particles are created slightly on either side of that event horizon, now you have a real problem, okay?

01:12:16.340 | Now, the pair has been separated by this event horizon.

01:12:21.500 | Now, they can both fall in, that's okay.

01:12:23.960 | But if one falls in and the other doesn't, it's stuck.

01:12:28.360 | It can't go back into the vacuum because now it has a charge or it has a spin or it has something.

01:12:34.940 | It's no longer the property of that vacuum it came from.

01:12:37.900 | It needs its pair to disappear.

01:12:39.640 | Now it's stuck.

01:12:41.240 | It exists.

01:12:41.920 | It's like you've made it real.

01:12:43.440 | So, in a sense, the black hole steals one of these virtual particles and forces the other to live.

01:12:52.160 | And if it'll escape, radiate out to infinity and look like, to an observer far away, that the black hole has actually radiated a particle.

01:13:05.140 | Now, the particle did not emanate from inside.

01:13:07.020 | It came from the vacuum.

01:13:08.960 | It stole it from empty space, from the nothingness that is the black hole.

01:13:13.620 | Now, the reason why this is very tricky is because in the process, because of this separation on either side of the event horizon, the particle it absorbs, it has to do with the switching of space and time that we talked about.

01:13:27.980 | But the particle it absorbs, well, from the outside, you might say, oh, it had negative momentum.

01:13:32.620 | It was falling in.

01:13:33.420 | From the inside, you say, well, this is actually motion and time.

01:13:36.280 | This is energy.

01:13:37.060 | It has negative energy.

01:13:39.060 | And as it absorbs negative energy, its mass goes down.

01:13:42.560 | The black hole gets a little lighter.

01:13:44.160 | And as it continues to do this, the black hole really begins to evaporate.

01:13:49.700 | It does more than just radiate.

01:13:50.960 | It evaporates away.

01:13:53.320 | And it's intriguing because Hawking said, look, this is going to look thermal, meaning featureless.

01:14:01.220 | It's going to have no information in it.

01:14:04.260 | It's going to be the most informationless possibility you could possibly come up with when you're radiating particles.

01:14:09.540 | It's just going to look like a thermal distribution of particles, like a hot body.

01:14:13.740 | And the temperature is going to only tell you about the mass, which you could tell from outside the black hole anyway.

01:14:18.760 | You know the mass of the black hole from the outside.

01:14:20.620 | So it's not telling you anything about the black hole.

01:14:23.000 | It's got no information about the black hole.

01:14:25.420 | Now you have a real problem.

01:14:26.860 | And when he first said it, a lot of people described that not everyone understood how really naughty he was being.

01:14:33.760 | He did.

01:14:37.060 | But some people who love quantum mechanics were really annoyed.

01:14:41.220 | Okay.

01:14:41.980 | People like Lenny Susskind, Gerard Atseuft, Nobel Prize winner.

01:14:45.560 | They were mad because it suggested something was fundamentally wrong with quantum mechanics, if it was right.

01:14:52.160 | And the reason why it says there's something fundamentally wrong with quantum mechanics is because quantum mechanics does not allow this.

01:14:58.660 | It does not allow quantum information to simply evaporate away and poof out of the universe and cease to exist.

01:15:07.380 | It's a violation of something called unitarity.

01:15:09.360 | But really the idea is it's the loss of quantum information that's intolerable.

01:15:13.460 | Quantum mechanics was built to preserve information.

01:15:16.320 | It's one of the sacred principles.

01:15:17.800 | As sacred as conservation of energy.

01:15:19.820 | In this example, more sacred.

01:15:21.400 | Because you can violate conservation of energy with Heisenberg's uncertainty principle a little tiny bit.

01:15:28.200 | But so sacred that it created what became coined as the black hole wars where people were saying, look, general relativity is wrong.

01:15:38.720 | Something's wrong with our thinking about the event horizon.

01:15:41.500 | Or quantum mechanics isn't what we think it is.

01:15:45.560 | But the two are not getting along anymore.

01:15:47.960 | And just to tell you how dramatic it is.

01:15:49.980 | So the temperature goes down with the mass of the black hole.

01:15:53.440 | Heavier a black hole.

01:15:55.120 | The cooler it is.

01:15:56.260 | So we don't see black holes evaporate.

01:15:58.140 | They're way too big.

01:15:59.080 | But as they get smaller and smaller, they get hotter and hotter.

01:16:02.640 | So as the black hole nears the end of this cycle of evaporating away, it takes a very long time.

01:16:08.200 | Much longer than the age of the universe.

01:16:11.260 | It will be as though the curtain, the event horizon is yanked up.

01:16:14.060 | Like it'll literally explode away.

01:16:16.360 | Just boom.

01:16:17.400 | And the event horizon, in principle, would be yanked up.

01:16:21.620 | Everything's gone.

01:16:23.280 | All that information that went into the black hole, all that sacred quantum stuff, gone.

01:16:27.780 | Poof.

01:16:28.400 | Okay?

01:16:29.380 | Because it's not in the radiation.

01:16:30.740 | Because the radiation has no information.

01:16:32.320 | And so it was an incredibly productive debate.

01:16:38.780 | Because in it are the signs of what will make gravity and quantum mechanics play nice together.

01:16:46.680 | You know, some quantum theory of gravity, whatever these clues are, and they're hard to assemble.

01:16:52.420 | If you want a quantum gravity theory, it has to correctly predict the temperature of a black hole, the entropy of a black hole.

01:16:59.420 | It has to have all of these correct features.

01:17:01.720 | The black hole is the place on which we can test quantum gravity.

01:17:05.640 | But it still has not been resolved.

01:17:07.720 | It has not been fully resolved.

01:17:09.380 | I looked up all the different ideas for the resolution.

01:17:11.900 | So there's the information loss, which is what you refer to.

01:17:15.840 | Right.

01:17:16.080 | It's perhaps the simplest, yes, most erratic resolution is that information is truly a loss.

01:17:21.520 | This would mean quantum mechanics, as we currently understand it, specifically unitarity, is incomplete or incorrect under these extreme gravitational conditions.

01:17:29.340 | I'm unhappy with that.

01:17:30.260 | I would not be happy with information loss.

01:17:32.420 | I love that it's telling us that there's this crisis, because I do think it's giving us the clues.

01:17:37.380 | And we have to take them seriously.

01:17:40.280 | For you, the gut is like...

01:17:42.820 | Unitarity is going to be preserved.

01:17:44.140 | Preserved.

01:17:44.700 | So quantum mechanics is...

01:17:46.700 | We have to come to the rescue.

01:17:47.900 | Lenny Susskind, in his book, Black Hole War, says, his subtitle is,

01:17:52.520 | My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics.

01:17:56.340 | Quantum mechanics, I love it.

01:17:57.940 | Something to that effect.

01:17:59.000 | So then from string theory, one of the resolutions is called fuzzballs.

01:18:03.080 | I love physicists so much.

01:18:04.200 | Originating from string theory, this proposal suggests that black holes aren't singularities surrounded by empty space and an event horizon.

01:18:11.500 | Instead, they are horizonless, complex, tangled objects, a.k.a. fuzzballs, made of strings and brains roughly the size of the would-be event horizon.

01:18:21.780 | There's no single point of infinite density and no true horizon to cross.

01:18:26.500 | In some sense, it says there's no interior to the black hole, nothing of a crosses.

01:18:29.720 | So I gave you this very nice story that there's no drama.

01:18:31.980 | Sometimes that's how it's described at the event horizon and you fall through and there's nothing there.

01:18:37.080 | This other idea says, well, hold on a second.

01:18:40.000 | If it's really strings, as I get close to this magnifying quality and slowing time down near the event horizon, it is as though I put a magnifying glass on things.

01:18:49.820 | And now the strings aren't so microscopic.

01:18:51.780 | They kind of shmure around.

01:18:52.940 | And then they get caught like a tangle around the event horizon and they just actually never fall through.

01:18:58.420 | I don't think that either, but it was interesting.

01:19:02.080 | So it's just adding a very large number of extra complex.

01:19:06.940 | Degrees of freedom.

01:19:08.500 | Yeah.

01:19:09.160 | There are no teeny tiny marbles to fall through.

01:19:11.980 | But it's similar to what we already have with quantum mechanics.

01:19:14.380 | It's just giving a deeper, more complicated.

01:19:17.160 | But it's really saying the interior is just not there ever.

01:19:19.040 | Nothing falls in.

01:19:19.900 | So the information gets out because it never went in in the first place.

01:19:22.360 | Oh, interesting.

01:19:22.860 | So there is a strong statement there.

01:19:24.380 | There's a strong statement there.

01:19:25.320 | Yeah.

01:19:25.500 | Okay.

01:19:25.720 | Soft hair challenges the classical no hair theorem by suggesting that black holes do possess subtle quantum, quote, hair.

01:19:33.380 | This isn't classical hair like charge, but very low energy quantum excitations, soft gravitons or photons at the event horizon that can store information about what fell in.

01:19:47.600 | Worth trying, but I also don't think that that's the case.

01:19:50.520 | So the no hair theorems are formal proofs that the black hole is this featureless, perfect fundamental particle that we talked about.

01:20:01.980 | That all you can ever tell about the black hole is its electrical charge, its mass, and its spin.

01:20:07.440 | And that it cannot possess other features.

01:20:10.060 | It has no hair is one way of describing it.

01:20:12.920 | And that those are proven mathematical proofs in the context of general relativity.

01:20:16.820 | So the idea is, well, therefore, I can know nothing about what goes into the black hole, so the information is lost.

01:20:22.360 | But if they could have hair, I could say that's my black hole, because it'd have features that I could distinguish, and it could encode the information that went in in this way.

01:20:31.040 | And the event horizon isn't so serious.

01:20:33.200 | It isn't such a stark demarcation between events inside and outside, and where I can't know what happened inside or outside.

01:20:40.280 | I don't think that's the resolution either, but it was worth a try.

01:20:43.020 | Okay, the pros and cons of that one.

01:20:45.060 | The pros, it works within the framework of quantum field theory in curved space-time, potentially requiring less radical modifications than fussballs or information loss.

01:20:53.620 | Recent work by Hawking Perry strongly revitalized this idea.

01:20:57.820 | The cons is that the precise mechanism by which information is encoded and transferred to the radiation is still debated and technically challenging to work out fully.

01:21:06.160 | And indeed, it needs to store a vast amount of information.

01:21:10.480 | Okay, another one.

01:21:11.980 | This is a weird one, boy.

01:21:13.320 | Is ER equals EPR.

01:21:15.780 | This is probably it, though.

01:21:17.520 | Oh, boy.

01:21:18.260 | So ER equals EPR is Einstein-Rosen Bridge equals Einstein-Podolsky-Rosen Bridge posits a deep connection between quantum entanglement and space-time geometry.

01:21:29.860 | Specifically, Einstein-Rosen Bridge, commonly known as wormholes.

01:21:35.760 | It suggests that entangled particles are connected by a non-traversible wormhole.

01:21:40.560 | So tiny wormholes connected.

01:21:43.100 | Okay.

01:21:43.760 | I can say that this is not a situation we can follow the chalk.

01:21:49.640 | We can't start at the beginning and calculate to the end.

01:21:52.120 | So it's still a conjecture.

01:21:54.600 | I think it's very profound, though.

01:21:57.840 | I kind of imagine Juan Maldicina, who's part of this, with Lenny Susskind.

01:22:02.220 | They were kind of like, oh, it's like ER equals EPR.

01:22:05.720 | They couldn't even formulate it properly.

01:22:07.240 | It was like an intuition that they had kind of landed on and now are trying to formalize.

01:22:11.900 | But to take a step back, one way of thinking about ER equals EPR, you have to talk about holography first.

01:22:19.280 | And holography, both Juan Maldicina really formalized it.

01:22:22.920 | Lenny Susskind suggested it.

01:22:24.520 | The idea of a black hole hologram is that all of the information in the black hole, whatever it is, whatever entropy as a measure of information, whatever the entropy of the black hole is, which is telling you how much information is hidden in there, how much information you don't have direct access to in some sense, is completely encoded in the area of the black hole.

01:22:45.140 | Meaning as the area grows, the entropy grows, it does not grow as the volume.

01:22:50.200 | This actually turns out to be really, really important.

01:22:53.880 | If I tried to pack a lot of information into a volume, more information than I could pack, let's say, on the surface of a black hole, I would simply make a black hole.

01:23:03.440 | And I would find out, oh, I can't have more information than I can fit on the surface.

01:23:08.580 | So Lenny coined this a hologram.

01:23:11.420 | People who take it very seriously say, well, again, maybe the interior of the black hole just doesn't exist.

01:23:16.280 | It's a holographic projection of this two-dimensional surface.

01:23:19.460 | In fact, maybe I should take it all the way and say so are we.

01:23:22.360 | The whole universe is a holographic projection of a lower-dimensional surface, right?

01:23:28.300 | And so people have struggled.

01:23:29.700 | Nobody's really landed it to find a universe version of it.

01:23:33.880 | Oh, maybe there's a boundary to the universe where all the information is encoded.

01:23:37.580 | And this entire three-dimensional reality that's so compelling and so convincing is actually just a holographic projection.

01:23:44.580 | Juan Maldicina did something absolutely brilliant.

01:23:48.060 | It's the most highly cited paper in the history of physics.

01:23:51.060 | It was published in the late 90s.

01:23:53.360 | It has a very opaque title that would not lead you to believe it's as revelatory as it is.

01:23:59.560 | But he was able to show that a universe, like in a box, with gravity in it, it's not the same universe we observe.

01:24:07.620 | It doesn't matter.

01:24:08.140 | It's just a hypothetical called an anti-de-sitter space.

01:24:10.420 | It's a universe in a box.

01:24:11.500 | It has gravity.

01:24:12.040 | It has black holes.

01:24:12.720 | It has everything gravity can do in it.

01:24:14.960 | On its boundary is a theory with no gravity, a universe that can be described with no gravity at all, so no black holes, and no information loss problem.

01:24:27.220 | And they're equivalent.

01:24:29.540 | That the interior universe in a box is a holographic projection of this quantum mechanics on the boundary.

01:24:39.440 | Pure quantum mechanics, purely unitary, no loss of information.

01:24:43.120 | None of this stuff could possibly be true.

01:24:46.160 | There can't be loss of information if this dictionary really works, if the interior is a hologram, a projection of the boundary.

01:24:55.120 | I know that's a lot.

01:24:56.960 | Yeah.

01:24:59.180 | So there's some mathematics there, there's physics, and then there's trying to conceive of what that actually means practically for us.

01:25:07.060 | Well, what it would mean for us is that information can't be lost, even if we don't know how to show it in the description in which there are black holes.

01:25:17.300 | It means it means it can't possibly be lost because it's equivalent to this description with no gravity in it at all, no event horizons, no black holes, just quantum mechanics.

01:25:28.720 | So it really strongly suggested that quantum mechanics was going to win in this battle, but it didn't show exactly how it was going to win.

01:25:39.020 | So then comes ER equals EPR.

01:25:41.980 | A visual way to imagine what this means.

01:25:44.720 | So ER has to do with little wormholes.

01:25:46.940 | EPR, Einstein, Podolsky, Rosen, has to do with quantum entanglement.

01:25:52.100 | The idea was, well, maybe the stuff that's interior to the black hole is quantum entangled, like EPR, quantum entangled, with the Hawking radiation outside the black hole that's escaping.

01:26:06.160 | And that quantum entanglement is what allows you to extract the information, because it's not actually physically moving from the interior to the exterior.

01:26:17.280 | It's just subtle quantum entanglement.

01:26:19.620 | And in fact, I can kind of think of the entire black hole.

01:26:25.180 | If I look at it, and it looks like a solid shadow cast on the sky, some region of space-time, if I look at it very closely, I will see, oh, no, it's actually sewn from these quantum wormholes, like embroidered.

01:26:38.560 | And so when I get up close, it's almost as though the event horizon isn't the fundamental feature on the space-time.

01:26:48.520 | The fundamental feature is the quantum entanglement embroidering the event horizon.

01:26:54.080 | The embroidering is just tiny wormholes.

01:26:56.500 | So the quantum entanglement is when two particles are connected at arbitrary distances.

01:27:03.840 | And they're connected by a wormhole.

01:27:05.740 | And in this case, they would be connected by a wormhole.

01:27:08.660 | So the reason why that's helpful, it helps you connect the interior to the exterior without trying to pass through the event horizon.

01:27:17.720 | The cons of the theory is highly conceptual and abstract.

01:27:23.180 | The exact mechanism for information retrieval via these non-traversable wormholes is not fully understood.

01:27:29.660 | Primarily explored in theoretical toy models.

01:27:34.220 | Whoa, Gemini going hard.

01:27:36.320 | Theoretical toy models like the anti-desider space, space-time, rather than realistic black holes.

01:27:45.020 | True.

01:27:45.800 | We do what we can do.

01:27:47.160 | And baby steps.

01:27:49.020 | So another idea to resolve the information paradox is firewalls.

01:27:54.020 | Proposed by Ameri, Marov, Polchinski, and Sully, AMPS.

01:28:00.360 | This is a more drastic scenario arising from analyzing the entanglement requirements of Hawking radiation to preserve unitarity and avoid information loss.

01:28:10.020 | They argued that the entanglement structure requires the event horizon not to be smooth, not to be the smooth and remarkable place predicted by general relativity, the equivalence principle.

01:28:21.700 | Instead, it must be a highly energetic region, a, quote, firewall that incinerates anything attempting to cross it.

01:28:30.540 | Okay, so yeah, that's a nice solution.

01:28:32.080 | Just destroy everything that crosses the, do you find this at all a convincing resolution to the information?

01:28:39.000 | I would say the firewall papers were fascinating and were very provocative and very important in making progress.

01:28:45.860 | I don't even think the authors of those papers thought firewalls were real.

01:28:49.080 | I think they were saying, look, we've been brushing too much under the rug.

01:28:53.700 | And if you look at the evaporation process, it's even worse than what you thought previously.

01:29:01.000 | It's so bad that I can't get away with some of these prior solutions that I thought I could get away with.

01:29:06.280 | There was a kind of duality idea or a complementarity idea that, oh, well, maybe one person thinks they fell in and one person thinks they never fell in and that's okay.

01:29:15.520 | You know, no big deal.

01:29:16.780 | They sort of exposed flaws in these kind of approaches and it actually reinvigorated the campaign to find a solution.

01:29:25.840 | So it stopped it from stalling.

01:29:27.800 | I don't think anyone really believes that the event horizon, at the event horizon, you'll find a firewall.

01:29:32.540 | But it did lead to things like the entangled wormholes embroidering a black hole, which was born out of an attempt to address the concerns that AMPS raised.

01:29:46.740 | So it did lead to progress.

01:29:49.360 | So for you, the resolution would...

01:29:51.540 | I'm going back to the vacuum.

01:29:53.560 | You're going back to the vacuum.

01:29:54.860 | The empty space, the beautiful event horizon.

01:29:56.900 | Yep.

01:29:57.340 | I'll give up locality, meaning that I will allow things to be connected non-locally by a wormhole.

01:30:08.180 | So that is the weirdest thing you're willing to allow for, which is arbitrary distance connection of particles through a wormhole.

01:30:16.340 | But quantum mechanics must be preserved.

01:30:18.700 | I'll entertain pretty weird things, but I think that's the one that sounds promising.

01:30:24.560 | The implications are so dramatic because this is why you start to hear things like, wait a minute, if the event horizon only exists when it's sewn out of these quantum threads, does that mean that gravity is fundamentally quantum mechanics?

01:30:38.540 | It's not that gravity and quantum mechanics get along, and I have a quantum gravity theory, and I now know how to quantize gravity.

01:30:44.740 | Actually, something much more dramatic.

01:30:46.240 | Gravity is just kind of emerging from this quantum description, that gravity isn't fundamental.

01:30:55.060 | And what is the only thing that we have when we go rock bottom, when we go deeper and deeper, smaller and smaller, is quantum mechanics.

01:31:03.420 | So all of this, like, space-time looks nice and smooth and continuous, but if I look at the quantum realm, I'll see everything sewn together out of quantum threads.

01:31:12.220 | And that space-time is not a smooth continuum all the way down.

01:31:17.860 | Now, people already thought that, but they thought it kind of came in chunks of space-time.

01:31:22.260 | Instead, maybe it's just quantum mechanics all the way down.

01:31:25.760 | Quantum threads, so these entangled particles connected by wormholes.

01:31:31.480 | So that's how you would, how would you even visualize a black hole in that way?

01:31:36.960 | So it's all, I mean, it's all sort of, from our perspective in terms of detecting things, the light going in, it's all still the same.

01:31:47.920 | But when you zoom in a lot.

01:31:49.400 | When you zoom in a lot to the quantum mechanical scale at which you're seeing the Hawking radiation,

01:31:55.740 | you would be noticing that there's some entanglement between the radiation that I could not explain before and the interior of the black hole.

01:32:04.440 | So it's now no longer a perfectly thermal spectrum with no features that only depends on the mass.

01:32:11.500 | It actually has a way to have an imprint of the information interior to the black hole in the particles that escape.

01:32:21.660 | And so now, in principle, I could sit there for a very long time.

01:32:26.000 | It might take longer than the age of the universe and collect all the Hawking radiation and see that it actually had details in it that are going to explain to me what was interior to the black hole.

01:32:35.920 | So the information is no longer lost.

01:32:38.180 | Yeah, so information is not being destroyed.

01:32:39.820 | So in theory, you should be able to get information.

01:32:42.660 | Now, I can't do that any more than I can recover the words on that piece of paper once it's been burnt.

01:32:48.180 | But that's a practical limitation, not a fundamental one.

01:32:50.920 | It's just too hard.

01:32:52.060 | But when I burn a piece of paper, technically, the information is all there somewhere.

01:32:56.680 | It's in the smoke.

01:32:57.580 | It's in the currents.

01:32:58.320 | It's in the molecules.

01:32:59.560 | It's in the ink molecules.

01:33:01.440 | But in principle, if I had took the age of the universe, I could probably reconstruct.

01:33:06.400 | I should be able to, in principle, reconstruct the piece of paper and all the words on it.

01:33:11.760 | Do you think a theory of everything that unifies general relativity and quantum mechanics is possible?

01:33:17.220 | So we're, like, skirting around it.

01:33:19.800 | Yeah, we're skirting around it.

01:33:21.180 | I think that this is the way to find that out.

01:33:23.300 | It's going to be on the terrain of black holes that we figure out if that's possible.

01:33:27.740 | I think that this is suggesting that there might not be a theory of quantum gravity,

01:33:34.440 | that gravity will emerge at a macroscopic level out of quantum phenomena.

01:33:39.740 | Now, we don't know how to do that yet.

01:33:42.300 | But these are all hints.

01:33:43.500 | Emerge.

01:33:44.800 | So a lot of the mathematics of anything that emerges from complex systems is very difficult to...

01:33:50.520 | The transition's very difficult, right?

01:33:52.520 | So if that's the case, there might not be a simple, clean equation that connects everything.

01:33:58.820 | There are examples of emergent phenomena which are very simple and clean.

01:34:02.240 | Like, I can just take electromagnetic scattering, which is law of physics,

01:34:06.800 | where particles scatter just by electromagnetically.

01:34:09.960 | And I have a lot of them, and I have a lot of them in this room, and they come to some average.

01:34:14.260 | Well, I call that temperature, right?

01:34:16.920 | And that one number, the fact that there's one number describing all of these gazillions of particles is an emergent quantity.

01:34:26.300 | There's no particle that carries around this fundamental property called temperature, right?

01:34:30.820 | It emerges from the collective behavior of tons and tons of particles.

01:34:34.700 | In some sense, temperature is not a fundamental quantity.

01:34:36.840 | It's not a fundamental law of nature, right?

01:34:40.560 | It's just what happens from the collective behavior.

01:34:44.660 | And that's what we'd be saying.

01:34:47.120 | We'd be saying, oh, this emerges from the collective behavior of lots and lots and lots of quantum interactions.

01:34:56.920 | So when do you think we would have some breakthroughs on the path towards theory of everything,

01:35:03.900 | showing that it's impossible or impossible, all that kind of stuff?

01:35:07.040 | If you look at the 21st century, say you move 100 years into the future and looking back,

01:35:12.420 | when do you think the breakthroughs will come?

01:35:15.320 | So I'll give you some hard problems.

01:35:16.740 | I guess my question is, how hard is this problem?

01:35:19.600 | Like, what does your gut say?

01:35:21.440 | Because, you know, finding the origin of life, figuring out consciousness, solving some of the major diseases,

01:35:27.360 | then there's the theory of everything, understanding this, resolving the information paradox.

01:35:32.180 | So these puzzles that are before us as a human civilization,

01:35:36.100 | physics, this feels like really one of the big ones.

01:35:41.100 | Of course, there could be other breakthroughs in physics that don't solve this.

01:35:47.880 | Yeah, we could discover dark matter, dark energy.

01:35:50.480 | We could discover extra spatial dimensions.

01:35:52.460 | We could discover that those three things are linked,

01:35:55.600 | that there's like a dark sector to the universe that's hiding in these extra dimensions.

01:35:59.460 | And that's something that I love to work on.

01:36:02.220 | I think it's really fascinating.

01:36:03.260 | All of those would also be clues about this question,

01:36:06.740 | but they wouldn't solve this problem.

01:36:09.600 | I think it's impossible to predict.

01:36:14.280 | There has been real progress.

01:36:15.740 | And the progress, as we've said, comes from the childlike curiosity of saying,

01:36:20.440 | well, I don't actually understand this.

01:36:22.360 | I'm going to keep leaning on it because I don't understand it.

01:36:25.040 | And then suddenly you realize nobody really understood it.

01:36:28.220 | So I don't know.

01:36:30.600 | Do I think it's a harder problem than the problem of the origin of life?

01:36:34.200 | I think it's technically a harder problem.

01:36:36.460 | But I don't know.

01:36:38.500 | Maybe the breakthrough will come.

01:36:41.120 | So when you mentioned discovering extra dimensions,

01:36:45.280 | what do you mean, what could that possibly mean?

01:36:50.480 | Well, we know that there are three spatial dimensions.

01:36:56.000 | We like to talk about time as a dimension.

01:36:58.180 | We can argue about whether that's the right thing to do.

01:37:01.440 | But we don't know why there are only three.

01:37:03.600 | It very well could be that there are extra spatial dimensions,

01:37:07.800 | that there's like a little origami of these tightly rolled up dimensions.

01:37:12.880 | Not all of them, not all the models require that they're small, but most do.

01:37:16.840 | String theory requires extra dimensions to make sense.

01:37:21.400 | But even if you feel very hostile towards string theory,

01:37:28.460 | there are lots of reasons to consider the viability of extra dimensions.

01:37:32.620 | And we think that they can trap little quantum energies in such a way that might align with the dark energy.

01:37:41.980 | The numerology is not perfect.

01:37:44.040 | It's a little bit subtle.

01:37:45.180 | It's hard to stabilize them.

01:37:48.420 | It's possible that there are these kind of quantum excitations that look a lot like dark matter.

01:37:54.380 | It's kind of an interesting idea that in the Big Bang,

01:37:58.500 | the universe was born with lots of these dimensions.

01:38:01.340 | They were all kind of wrapped up in the early universe.

01:38:05.080 | And what we're really trying to understand is why did three get so big?

01:38:11.600 | And why did the others stay so small?

01:38:14.080 | Is it possible to have some kind of natural selection of dimensions kind of situation?

01:38:18.360 | Yeah, there is, actually.

01:38:19.780 | And people have worked on that.

01:38:21.440 | Is there a reason why it's easier to unravel three?

01:38:26.280 | Some people think about strings and brains wrapping up in the extra dimensions,

01:38:30.700 | causing a kind of constriction,

01:38:32.200 | but preferentially loosening up in three.

01:38:36.200 | And sometimes we look at exactly models like that,

01:38:38.820 | which have to do with the origami being resistant to change in a certain way

01:38:44.220 | that only allows three to unravel and keeps the others really taut.

01:38:48.300 | But then there are other ideas that we're actually living on a three-dimensional membrane

01:38:53.640 | that moves through these higher dimensions.

01:38:57.300 | And so the reason we don't notice them isn't because they're small.

01:38:59.680 | Maybe they're not small at all.

01:39:00.940 | But it's because we're stuck to this membrane.

01:39:03.200 | So we're unaware of these extra directions.

01:39:06.380 | Is it possible that there's other intelligent alien civilizations out there

01:39:10.960 | that are operating on a different membrane?

01:39:14.360 | This is a bit of an out-there question,

01:39:17.380 | but I ask it more kind of seriously.

01:39:19.460 | Is it possible, do you think, from a physics perspective,

01:39:22.400 | to exist on a slice of what the universe is capable of?

01:39:28.780 | I think it is certainly mathematically possible on paper

01:39:35.020 | to imagine a higher dimensional universe with more than one membrane.

01:39:40.100 | And if things are mathematically possible,

01:39:44.320 | I often wonder if nature will try it out.

01:39:46.360 | Yeah.

01:39:48.080 | Which is how people get into the strange territory of talking about a multiverse.

01:39:52.900 | Because if you start to say,

01:39:54.440 | one of the aspirations was,

01:39:56.620 | in the same way that we identified the law of electroweak theory of matter,

01:40:02.880 | that it was a single description

01:40:04.840 | and exactly landed on the description that matched observations,

01:40:09.580 | people were hoping the same thing would happen

01:40:11.700 | for a kind of theory that also incorporated gravity.

01:40:16.120 | There would be this one beautiful law,

01:40:18.180 | but instead they got a proliferation,

01:40:19.940 | all of which did okay or did equally badly.

01:40:23.100 | And they suddenly had trouble finding,

01:40:25.860 | not only finding a single one,

01:40:28.160 | but sort of that would just beg a new question,

01:40:31.760 | which is, well, why that one?

01:40:33.420 | And if nature can do something,

01:40:36.380 | won't she do anything she can try?

01:40:38.580 | And so maybe we really are just one example

01:40:42.640 | in an infinite sea of possible universes

01:40:45.960 | with slightly different laws of physics.

01:40:47.360 | So if I can do some of these things on paper,

01:40:51.460 | like imagine a higher dimensional space

01:40:54.000 | in which I'm confined to a brain

01:40:55.260 | and there's another brain or maybe a whole array of them,

01:40:59.400 | maybe nature's tried that out somewhere.

01:41:00.960 | Maybe that's been tried out here.

01:41:03.040 | And then, yes, is it possible

01:41:06.260 | that there's life and civilizations on those other brains?

01:41:09.240 | Yeah, but we can't communicate with them.

01:41:11.500 | They'd be like in a shadow space.

01:41:14.140 | Can you seriously say we can't communicate with them?

01:41:16.280 | Well, no, that's fair.

01:41:17.860 | I'm limited in my communication

01:41:19.940 | because I'm glued to the brain,

01:41:21.100 | but some things can move.

01:41:22.520 | We call the bulk through the bulk.

01:41:24.880 | Gravity, for instance, a gravitational wave.

01:41:27.380 | So I could design a gravitational communicator,

01:41:30.460 | communication system,

01:41:32.180 | and I could send gravitational waves through the bulk.

01:41:35.060 | And how SETI is doing with light into space,

01:41:39.320 | I could send signals into the bulk,

01:41:43.720 | telling them where we are and what we do

01:41:45.880 | and singing songs.

01:41:47.360 | Of course, sending gravitational waves is very expensive.

01:41:49.940 | We don't know how to make it.

01:41:50.600 | Very expensive, very hard to localize.

01:41:52.560 | They tend to be long wavelength

01:41:54.180 | and very hard to do.

01:41:55.980 | A lot of energy moving around.

01:41:57.300 | A lot of energy.

01:41:57.660 | So is it possible that the membranes are,

01:42:00.860 | quote-unquote, hairy in other ways,

01:42:02.840 | like some kind of weird quantum thing?

01:42:04.860 | It is possible that there's other things

01:42:06.300 | that live in the bulk.

01:42:07.160 | I mean, last night I was calculating weight,

01:42:10.080 | looking at something that lives in the bulk.

01:42:13.360 | Okay, this is fascinating.

01:42:14.220 | So, I mean, okay,

01:42:15.480 | can we take a little bit more seriously

01:42:17.160 | about the whole one?

01:42:18.300 | When I look out there at the stars,

01:42:22.100 | I, from a basic intuition,

01:42:24.840 | cannot possibly imagine

01:42:28.520 | there's not just alien civilizations everywhere.

01:42:33.240 | life is so damn good.

01:42:34.960 | Like you said, nature tries stuff out.

01:42:37.360 | Yeah.

01:42:37.760 | Nature's an experimenter.

01:42:39.580 | And I just can't,

01:42:41.160 | just basic sort of observation.

01:42:46.060 | Life, you said somewhere that you like extremophiles.

01:42:50.340 | Life just figures shit out.

01:42:53.980 | It just finds a way to survive.

01:42:56.200 | Now, there could be something magical

01:42:57.800 | about the origin of life,

01:42:59.100 | the first spark,

01:43:00.120 | but like I can't even see that.

01:43:01.540 | It's just over and over and over.

01:43:02.800 | I bet, actually,

01:43:04.060 | once the story is fully told

01:43:06.060 | and figured out,

01:43:06.780 | life originated on Earth

01:43:08.720 | almost right away

01:43:09.540 | and did so like billions of times

01:43:12.100 | in multiple places,

01:43:14.680 | just over and over and over and over.

01:43:16.960 | that seems to be the thing

01:43:18.700 | that just whatever is the life force

01:43:22.380 | behind this whole thing

01:43:24.200 | seems to create life,

01:43:27.600 | seems to be a creator of different sorts.

01:43:30.720 | Yeah.

01:43:31.460 | The very,

01:43:32.540 | from the very original primordial soup of things,

01:43:35.560 | it just creates stuff.

01:43:36.620 | So I just can't imagine,

01:43:37.820 | but we don't see the aliens, so.

01:43:39.800 | Right, yeah.

01:43:40.600 | We don't even have to go to something as crazy

01:43:42.400 | as Extra Dimensions

01:43:43.380 | and Brain Worlds and all of that.

01:43:44.900 | what's happening right now

01:43:46.380 | in the past 30 years in astronomy

01:43:48.560 | looking at real objects

01:43:50.780 | is that the number of planets,

01:43:53.420 | exoplanets outside our solar system

01:43:55.220 | has absolutely proliferated.

01:43:57.220 | There are probably more planets

01:43:59.760 | in the Milky Way galaxy

01:44:00.860 | than there are stars.

01:44:02.020 | And now we have a real quandary.

01:44:04.420 | Not, I don't think it's a quandary.

01:44:05.800 | I think it's really exciting.

01:44:06.880 | It becomes impossible.

01:44:08.760 | What you just said,

01:44:09.580 | I totally agree with.

01:44:10.320 | It becomes impossible to imagine

01:44:11.920 | that life was not sparked somewhere else

01:44:14.760 | in our Milky Way galaxy

01:44:16.520 | and maybe even in our local neighborhood

01:44:18.680 | of the Milky Way galaxy,

01:44:20.320 | maybe within a few hundred light years

01:44:22.100 | of our solar system.

01:44:24.200 | So my gut says

01:44:25.680 | like some crazy amount

01:44:27.800 | of solar systems

01:44:30.700 | have life.

01:44:33.260 | Bacterial life somewhere

01:44:34.900 | at some point in their history

01:44:37.540 | had some bacterial type of life.

01:44:41.140 | Something like bacterial,

01:44:42.800 | maybe it's totally different kinds of life.

01:44:44.200 | So then I'm just facing with the question,

01:44:46.720 | it's like,

01:44:47.120 | why have we not clearly seen

01:44:49.960 | alien civilizations?

01:44:51.780 | And there,

01:44:52.380 | the answer,

01:44:53.260 | I don't find any great filter answer convincing.

01:44:59.580 | There's just no way I can imagine

01:45:02.080 | an advanced alien civilization

01:45:03.620 | not avoiding its own destruction.

01:45:05.300 | I can see a lot of them

01:45:06.540 | getting into trouble.

01:45:07.240 | I can see how we humans

01:45:08.540 | are really like 50-50 here.

01:45:10.900 | Well, isn't that kind of appalling?

01:45:13.420 | I mean, just take that statement.

01:45:14.860 | We've only been around for like,

01:45:16.460 | I mean,

01:45:17.080 | a couple hundred thousand years tops,

01:45:19.000 | you know?

01:45:19.820 | That is not very long

01:45:22.340 | and we're at a 50-50.

01:45:23.820 | I mean, that's unbelievable.

01:45:25.820 | I mean, it's indisputable

01:45:27.360 | that we have created the means

01:45:29.740 | at least potentially

01:45:31.580 | for our own destruction.

01:45:32.840 | Will we learn from our mistakes?

01:45:34.720 | Will we avert course

01:45:37.000 | and save ourselves?

01:45:38.400 | One hopes so, right?

01:45:39.760 | But even the concept

01:45:41.600 | that it's conceivable,

01:45:42.780 | whales have not

01:45:44.080 | invented a way

01:45:45.340 | to kill themselves,

01:45:46.060 | to wipe out all whales

01:45:48.460 | and Earth

01:45:49.240 | and life on Earth.

01:45:51.420 | That's one way to see it,

01:45:52.600 | but I actually see it

01:45:53.540 | as a feature,

01:45:53.980 | not a bug,

01:45:54.520 | when you look at the entirety

01:45:55.600 | of the universe

01:45:56.640 | because it does seem

01:45:59.760 | that the mechanism

01:46:00.700 | of evolution

01:46:01.460 | constantly creates,

01:46:04.560 | you want to operate

01:46:06.900 | on the verge of destruction,

01:46:08.220 | it seems like.

01:46:09.200 | I mean, the predator

01:46:09.920 | and prey dynamic

01:46:10.720 | is really effective

01:46:12.440 | at creating,

01:46:13.420 | at accelerating evolution

01:46:16.200 | and development.

01:46:16.760 | It seems like us

01:46:18.240 | being able to destroy ourselves

01:46:19.820 | is a really powerful way

01:46:21.580 | to give us a chance

01:46:23.420 | to really get our shit together

01:46:25.020 | and to flourish,

01:46:25.600 | to develop,

01:46:26.180 | to innovate,

01:46:26.780 | to go out amongst the stars

01:46:29.500 | or 50-50 destroy ourselves.

01:46:31.680 | which I think me as a human

01:46:34.440 | is a horrible thing,

01:46:35.300 | but if there's a lot

01:46:36.360 | of other alien civilizations,

01:46:37.540 | that's a pretty cool thing.

01:46:38.560 | You want to give everybody

01:46:39.740 | nuclear weapons,

01:46:40.560 | half of them will figure it out,

01:46:43.220 | half of them won't.

01:46:44.520 | You mean everyone,

01:46:45.180 | all these civilizations.

01:46:46.100 | All these civilizations.

01:46:47.180 | And then the ones

01:46:48.480 | that figure it out

01:46:49.280 | will figure out

01:46:50.000 | some incredible technologies

01:46:51.200 | about how to expand,

01:46:52.440 | how to develop

01:46:53.200 | and all that kind of stuff.

01:46:53.940 | Right.

01:46:54.340 | You could use a kind of

01:46:55.620 | evolutionary Darwinian

01:46:56.800 | natural selection on that

01:46:58.700 | where survival

01:47:00.300 | isn't just in a harsh,

01:47:02.760 | naturally induced climate change,

01:47:04.500 | but it's because

01:47:05.040 | of a nuclear holocaust.

01:47:06.180 | And then something

01:47:08.340 | will be created

01:47:10.460 | that is now impervious to that,

01:47:12.540 | that now knows how to survive.

01:47:14.220 | Yep, exactly.

01:47:14.800 | So why haven't we seen them?

01:47:16.180 | Right.

01:47:16.560 | Well, because that's

01:47:18.180 | a pretty big bar.

01:47:19.540 | So if you look at the,

01:47:20.420 | just to say,

01:47:21.180 | for comparison,

01:47:22.300 | dinosaurs,

01:47:23.100 | you know,

01:47:24.100 | 250 million years.

01:47:25.620 | I mean,

01:47:27.300 | maybe not very bright.

01:47:29.080 | Didn't invite fire.

01:47:32.340 | Didn't write sonnets.

01:47:33.840 | Yeah.

01:47:34.780 | They didn't contemplate

01:47:35.680 | the origin of the universe,

01:47:36.420 | but they lived.

01:47:38.480 | And in a benign situation

01:47:42.740 | without confronting

01:47:43.840 | their own demise

01:47:44.580 | at their own hands.

01:47:45.400 | Paws.

01:47:46.420 | Hooves.

01:47:47.340 | So it's just

01:47:49.480 | a sheer numbers game.

01:47:50.320 | That's a long time.

01:47:51.120 | 250 million years.

01:47:52.520 | I do think,

01:47:54.380 | though,

01:47:54.800 | that life can flourish

01:47:56.040 | without wanting

01:47:56.800 | to manipulate

01:47:57.700 | its environment.

01:47:59.020 | And that we do see

01:48:01.940 | many examples

01:48:03.480 | of species on Earth

01:48:04.600 | that are very long-lived,

01:48:06.080 | very, very long-lived,

01:48:08.220 | and have very different

01:48:09.640 | states of consciousness.

01:48:11.320 | They have

01:48:12.120 | the jellyfish

01:48:13.940 | does not even have

01:48:14.800 | a localized brain.

01:48:15.920 | I don't think

01:48:17.240 | they have a heart

01:48:17.920 | or blood.

01:48:18.540 | I mean,

01:48:18.960 | they're really different

01:48:19.740 | from us.

01:48:20.300 | Okay.

01:48:20.940 | And that's what I think

01:48:22.060 | we have to start thinking about

01:48:22.960 | when we think about aliens.

01:48:23.940 | Those species

01:48:26.060 | have lived

01:48:26.500 | for a very,

01:48:27.320 | very long time.

01:48:28.140 | They even show

01:48:28.640 | some evidence

01:48:29.220 | of immortality.

01:48:30.100 | You can wound one

01:48:32.040 | badly,

01:48:33.020 | and there are certain jellyfish

01:48:34.500 | that will go back

01:48:35.420 | into a kind of

01:48:36.860 | pre-state

01:48:38.180 | and start over.

01:48:39.160 | So I think

01:48:40.600 | we're very attached

01:48:41.680 | to imagining

01:48:42.600 | creatures like us

01:48:43.640 | that manipulate technology,

01:48:45.440 | and I think

01:48:48.480 | we have to be

01:48:48.900 | way more imaginative

01:48:50.100 | if we're going

01:48:51.720 | to really take seriously

01:48:52.840 | life in the universe.

01:48:53.660 | Yeah,

01:48:54.180 | they might not

01:48:55.100 | prioritize conquest

01:48:56.440 | and expansion.

01:48:57.780 | They might not

01:48:59.600 | be violent.

01:49:00.220 | They might not

01:49:01.600 | be violent.

01:49:02.140 | Like us humans.

01:49:03.440 | They might be solitary.

01:49:05.380 | They might not

01:49:06.160 | be social.

01:49:06.680 | They might not

01:49:07.300 | move in groups.

01:49:08.040 | They might not

01:49:08.860 | want to leave records.

01:49:09.980 | They might,

01:49:12.480 | again,

01:49:12.820 | not have a localized

01:49:13.860 | brain or have

01:49:15.660 | a completely different

01:49:16.380 | kind of nervous system.

01:49:17.180 | I think all we can

01:49:18.620 | say about life

01:49:19.300 | is it has something

01:49:20.340 | to do with moving

01:49:21.220 | electrons around.

01:49:22.020 | And,

01:49:23.680 | like,

01:49:24.720 | neurologically,

01:49:26.080 | we move electrons

01:49:27.140 | through our nervous system.

01:49:28.520 | Our brain

01:49:29.220 | has electrical

01:49:30.100 | configurations.

01:49:31.020 | We metabolize

01:49:32.700 | food,

01:49:33.600 | and that has

01:49:34.500 | to do with

01:49:35.220 | getting energy,

01:49:37.140 | electrical energy

01:49:38.660 | in some sense,

01:49:39.280 | out of what we're

01:49:40.840 | eating.

01:49:41.160 | We have organisms

01:49:42.000 | on the earth

01:49:42.460 | that can eat rocks.

01:49:43.240 | It's quite amazing.

01:49:44.300 | Minerals.

01:49:45.000 | I mean,

01:49:45.280 | talk about

01:49:45.700 | extremophiles.

01:49:46.500 | They can metabolize

01:49:48.000 | things that

01:49:48.380 | were impossible

01:49:50.500 | to metabolize.

01:49:51.240 | And so,

01:49:51.660 | again,

01:49:52.500 | I think we have

01:49:54.600 | to kind of

01:49:55.000 | open our minds

01:49:56.140 | to how strange

01:49:57.300 | that could be

01:49:58.080 | and how different

01:50:00.300 | from us.

01:50:00.700 | And we are

01:50:01.140 | the only example

01:50:02.000 | even here on earth

01:50:03.360 | that does

01:50:05.200 | manipulate its

01:50:06.740 | environment

01:50:07.120 | in that extreme

01:50:08.340 | way.

01:50:08.620 | mean,

01:50:09.500 | can you think

01:50:09.860 | of life

01:50:10.400 | as,

01:50:10.780 | because you said

01:50:12.080 | electrons,

01:50:12.580 | is there some

01:50:15.140 | degree of

01:50:16.460 | information processing

01:50:17.620 | required?

01:50:18.160 | So,

01:50:18.620 | like,

01:50:18.860 | it does

01:50:20.100 | something

01:50:20.540 | interesting

01:50:21.180 | in quotes

01:50:22.400 | with information.

01:50:23.720 | I think there

01:50:24.940 | are arguments

01:50:25.600 | like that.

01:50:26.360 | How entropy

01:50:27.940 | is changing

01:50:28.500 | from the beginning

01:50:29.080 | of the universe

01:50:29.700 | to today.

01:50:31.020 | How life

01:50:32.420 | lowers entropy

01:50:34.220 | by organizing

01:50:35.420 | things,

01:50:35.980 | but it

01:50:36.420 | costs more

01:50:37.240 | as a whole

01:50:37.740 | system.

01:50:38.260 | So,

01:50:38.920 | the whole

01:50:39.220 | entropy

01:50:39.540 | of the whole

01:50:40.020 | system

01:50:40.380 | goes up.

01:50:40.960 | But,

01:50:41.320 | of course,

01:50:43.000 | I organized

01:50:44.500 | things today

01:50:45.320 | and reduced

01:50:46.060 | the entropy

01:50:46.660 | of certain

01:50:47.800 | things in order

01:50:48.380 | to get up

01:50:48.920 | and get here.

01:50:49.500 | And even

01:50:51.540 | having this

01:50:52.040 | conversation,

01:50:52.480 | organizing

01:50:53.160 | thoughts

01:50:53.860 | out of the

01:50:55.220 | cloud of

01:50:55.880 | information.

01:50:56.480 | But it

01:50:57.200 | comes at the

01:50:57.800 | cost of the

01:50:58.240 | entire system

01:50:58.940 | increasing

01:50:59.540 | entropy.

01:51:01.400 | So,

01:51:01.640 | I do think

01:51:02.120 | there's probably

01:51:02.740 | a very interesting

01:51:03.420 | way to talk

01:51:03.900 | about life

01:51:04.320 | in this

01:51:04.640 | way.

01:51:04.840 | I'm sure

01:51:05.900 | somebody has.

01:51:06.700 | Yeah,

01:51:07.220 | it creates

01:51:08.020 | local pockets

01:51:08.920 | of low

01:51:09.280 | entropy.

01:51:09.640 | And then

01:51:10.420 | the kind

01:51:11.780 | of mechanism,

01:51:12.220 | the kind

01:51:12.640 | of object,

01:51:13.100 | the kind

01:51:13.500 | of life

01:51:14.520 | form that

01:51:14.900 | could do

01:51:15.220 | that probably

01:51:15.800 | could take

01:51:16.300 | arbitrary

01:51:17.080 | forms.

01:51:18.540 | And you

01:51:19.200 | could think

01:51:19.520 | now if you

01:51:20.140 | could reduce

01:51:20.640 | it all to

01:51:21.080 | information,

01:51:21.540 | now you

01:51:21.920 | could start

01:51:22.260 | to think

01:51:22.600 | about

01:51:22.860 | physics.

01:51:23.280 | And then

01:51:24.480 | the realm

01:51:24.800 | of physics

01:51:25.260 | was the

01:51:26.240 | multiverse

01:51:26.800 | and all this

01:51:27.260 | kind of

01:51:27.500 | stuff.

01:51:27.820 | You could

01:51:29.540 | start to

01:51:30.080 | think about,

01:51:30.620 | okay,

01:51:30.920 | how do I

01:51:31.440 | detect those

01:51:33.220 | pockets of

01:51:34.040 | low

01:51:34.260 | entropy?

01:51:34.580 | Yeah.

01:51:35.660 | I mean,

01:51:36.060 | people have

01:51:36.480 | tried to

01:51:36.940 | make arguments

01:51:37.640 | like that.

01:51:38.160 | Like,

01:51:38.420 | can I look

01:51:39.260 | for entropic

01:51:41.260 | arguments that

01:51:42.500 | might suggest

01:51:44.260 | we've done

01:51:45.100 | this before?

01:51:47.640 | the Big Bang

01:51:48.580 | has happened

01:51:49.220 | before.

01:51:50.140 | So is it

01:51:51.460 | possible that

01:51:51.940 | there's some

01:51:52.360 | kind of

01:51:52.740 | physics

01:51:53.160 | explanation

01:51:53.800 | why we

01:51:54.400 | haven't

01:51:54.600 | seen the

01:51:55.000 | aliens?

01:51:55.380 | Like we

01:51:55.820 | said,

01:51:56.040 | membranes.

01:51:56.720 | I don't

01:51:57.900 | think membranes

01:51:58.440 | is going

01:51:58.740 | to explain

01:51:59.220 | why we

01:51:59.580 | don't see

01:51:59.900 | them in

01:52:00.160 | the Milky

01:52:00.440 | Way.

01:52:00.700 | I think

01:52:01.280 | that is

01:52:01.600 | just a

01:52:01.980 | problem

01:52:02.180 | we're

01:52:02.380 | stuck

01:52:02.600 | with.

01:52:02.900 | Whether

01:52:03.400 | or not

01:52:03.680 | there are

01:52:03.880 | extra

01:52:04.080 | dimensions

01:52:04.480 | or

01:52:05.240 | whether

01:52:05.520 | or not

01:52:05.840 | there's

01:52:06.080 | life

01:52:06.340 | in

01:52:06.540 | another

01:52:06.960 | membrane,

01:52:07.640 | I think

01:52:09.420 | we know

01:52:09.760 | that even

01:52:10.180 | just in

01:52:10.680 | our

01:52:11.000 | galaxy,

01:52:11.460 | which is

01:52:11.860 | a very

01:52:12.220 | small

01:52:12.500 | part of

01:52:12.840 | the

01:52:15.040 | 300

01:52:15.680 | billion

01:52:16.040 | stars,

01:52:16.360 | something

01:52:16.720 | like

01:52:17.000 | that.

01:52:17.360 | A whole

01:52:18.500 | kind of

01:52:19.180 | variety of

01:52:19.820 | possibilities

01:52:20.280 | to be

01:52:20.580 | explored

01:52:20.900 | by nature

01:52:22.220 | in the

01:52:22.980 | same way

01:52:23.260 | that we're

01:52:23.460 | describing it.

01:52:24.060 | And I

01:52:24.640 | think you're

01:52:25.000 | absolutely

01:52:25.260 | right.

01:52:25.460 | When life

01:52:26.540 | was kicked

01:52:27.000 | off,

01:52:27.420 | first

01:52:27.820 | sparked

01:52:28.320 | here on

01:52:29.340 | Earth,

01:52:29.700 | it was

01:52:30.520 | voracious.

01:52:31.080 | Now it

01:52:32.080 | took a

01:52:32.460 | really long

01:52:33.080 | time,

01:52:33.380 | though,

01:52:33.600 | to get

01:52:34.120 | to

01:52:34.360 | multicellularity.

01:52:35.400 | I think

01:52:36.000 | that's

01:52:36.400 | interesting.

01:52:36.860 | That's

01:52:37.260 | weird.

01:52:37.520 | It's

01:52:37.980 | weird.

01:52:38.300 | It took

01:52:38.920 | a really,

01:52:39.660 | really long

01:52:40.780 | time to

01:52:41.160 | become

01:52:41.400 | multicellular.

01:52:42.820 | but it

01:52:43.260 | did not

01:52:44.360 | take long

01:52:45.080 | just to

01:52:46.040 | start.

01:52:46.340 | Yeah.

01:52:47.680 | What do

01:52:48.120 | you think

01:52:48.340 | is the

01:52:48.680 | hardest

01:52:49.020 | thing

01:52:49.740 | on the

01:52:51.080 | chain

01:52:51.500 | of

01:52:51.780 | leaps

01:52:52.240 | that

01:52:52.760 | got

01:52:53.580 | to

01:52:53.780 | humans?

01:52:54.240 | I

01:52:54.800 | would

01:52:55.080 | say

01:52:55.780 | multicellularity,

01:52:57.800 | which is

01:52:58.180 | strictly an

01:52:58.880 | energy

01:52:59.400 | problem,

01:53:00.120 | I think.

01:53:01.240 | Again,

01:53:02.180 | it's just

01:53:02.560 | like,

01:53:02.780 | can

01:53:02.960 | electrons

01:53:03.600 | flow the

01:53:04.800 | right way?

01:53:05.420 | And

01:53:07.100 | is it

01:53:08.180 | energetically

01:53:08.960 | favorable

01:53:09.520 | for

01:53:11.040 | multicellularity

01:53:12.800 | to exist?

01:53:14.320 | Because if

01:53:14.660 | it's

01:53:14.860 | energetically

01:53:15.460 | expensive,

01:53:15.940 | it's not

01:53:16.360 | going to

01:53:16.780 | succeed.

01:53:17.180 | And if

01:53:18.360 | it's

01:53:18.560 | energetically

01:53:19.080 | favorable,

01:53:19.440 | it's going

01:53:19.860 | to take

01:53:20.240 | off.

01:53:20.600 | It's

01:53:21.180 | really

01:53:21.480 | just,

01:53:21.860 | and that's

01:53:22.820 | why I

01:53:23.120 | also think

01:53:23.840 | that going

01:53:24.420 | from

01:53:24.860 | inanimate

01:53:25.760 | to

01:53:26.740 | to

01:53:28.760 | animate

01:53:29.520 | is

01:53:30.560 | probably

01:53:31.220 | gray.

01:53:32.400 | Like,

01:53:33.460 | the

01:53:33.620 | transition

01:53:34.120 | is

01:53:34.420 | gray.

01:53:35.360 | At

01:53:36.060 | what

01:53:36.340 | point

01:53:36.700 | we

01:53:36.980 | call

01:53:37.280 | something

01:53:37.860 | fully

01:53:38.660 | alive?

01:53:39.300 | Famously,

01:53:40.420 | it's hard

01:53:40.940 | to make

01:53:41.580 | a nice

01:53:41.980 | list of

01:53:42.820 | bullet

01:53:43.520 | points that

01:53:44.260 | need to be

01:53:44.780 | met in

01:53:45.140 | order to

01:53:45.560 | declare

01:53:45.820 | something

01:53:46.220 | alive.

01:53:46.720 | Is a

01:53:47.880 | virus

01:53:48.240 | alive?

01:53:48.820 | I mean,

01:53:49.180 | I don't

01:53:49.480 | know,

01:53:49.680 | is a

01:53:50.200 | prion

01:53:50.640 | alive?

01:53:51.400 | they seem

01:53:52.620 | to do

01:53:52.920 | some

01:53:53.180 | things,

01:53:53.460 | but they

01:53:53.800 | kind of

01:53:54.640 | rely on

01:53:55.040 | stealing

01:53:55.340 | other

01:53:56.180 | DNA

01:53:56.560 | and

01:53:56.880 | replicating

01:53:57.440 | and

01:53:57.720 | I

01:53:58.400 | don't

01:53:58.540 | know,

01:53:58.780 | I guess

01:53:59.240 | they're

01:53:59.360 | not

01:53:59.560 | alive.

01:53:59.820 | But I

01:54:00.320 | mean,

01:54:00.440 | the point

01:54:00.820 | is that

01:54:01.240 | it really

01:54:01.640 | at the

01:54:01.900 | end of

01:54:02.080 | the day,

01:54:02.220 | I really

01:54:02.580 | think

01:54:02.900 | it's

01:54:03.100 | just,

01:54:03.460 | you asked

01:54:04.040 | if it's

01:54:04.320 | just

01:54:04.480 | physics,

01:54:04.800 | I mean,

01:54:05.140 | I think

01:54:05.500 | it's

01:54:05.740 | just

01:54:06.040 | these

01:54:06.380 | rules

01:54:07.400 | of

01:54:07.580 | energetics.

01:54:08.300 | And the

01:54:09.120 | gray area

01:54:09.700 | between

01:54:10.040 | the

01:54:10.380 | non-living

01:54:11.000 | and the

01:54:11.300 | living

01:54:11.580 | is way

01:54:13.220 | simpler

01:54:13.560 | just

01:54:13.880 | on

01:54:14.300 | Earth.

01:54:14.580 | And you

01:54:14.840 | said

01:54:14.980 | it's

01:54:15.120 | already

01:54:15.340 | complicated

01:54:15.820 | on Earth,

01:54:16.200 | but it's

01:54:16.560 | probably

01:54:16.860 | even more

01:54:17.320 | complicated

01:54:17.700 | elsewhere,

01:54:18.100 | where the

01:54:18.600 | chemistry

01:54:18.900 | could be

01:54:19.240 | anything.

01:54:19.520 | Carbon

01:54:20.220 | is really

01:54:20.780 | cool and

01:54:21.780 | really useful

01:54:22.600 | because it

01:54:23.540 | finds a lot,

01:54:24.160 | it's nice,

01:54:24.720 | it finds a lot

01:54:26.240 | of ways to

01:54:26.880 | combine with

01:54:27.460 | other things

01:54:27.900 | and that's

01:54:28.340 | complexity and

01:54:29.080 | complexity is

01:54:30.340 | the kind of

01:54:30.900 | thing you

01:54:31.240 | need for

01:54:32.160 | life.

01:54:32.420 | You can't

01:54:32.900 | have a

01:54:33.320 | very simple

01:54:33.940 | linear chain

01:54:34.640 | and expect

01:54:35.060 | to get

01:54:35.340 | life.

01:54:35.580 | But I

01:54:36.520 | don't know,

01:54:36.780 | maybe sulfur

01:54:37.300 | would do

01:54:37.660 | okay.

01:54:37.980 | Okay,

01:54:39.420 | as we get

01:54:39.980 | progressively

01:54:40.540 | towards crazier

01:54:41.560 | and crazier

01:54:42.040 | ideas.

01:54:42.460 | So we

01:54:43.300 | talked about

01:54:43.720 | these

01:54:43.920 | microscopic

01:54:44.340 | wormholes,

01:54:45.100 | which my

01:54:47.020 | mind is

01:54:47.460 | still blown

01:54:48.360 | away by

01:54:48.720 | that.

01:54:48.920 | But if

01:54:49.680 | we talk

01:54:49.940 | a little

01:54:50.700 | bit more

01:54:51.000 | seriously

01:54:51.360 | about

01:54:51.860 | wormholes

01:54:52.820 | in general,

01:54:53.620 | also called

01:54:55.160 | the Einstein

01:54:55.860 | Rosenbridges,

01:54:56.780 | to what

01:54:57.900 | degree do

01:54:58.340 | you think

01:54:58.580 | they're

01:54:58.860 | actually

01:54:59.480 | possible

01:55:00.280 | as a

01:55:01.400 | thing to

01:55:01.880 | study,

01:55:02.480 | creeping

01:55:03.620 | towards

01:55:04.240 | the

01:55:05.360 | possibility

01:55:06.080 | maybe

01:55:07.600 | centuries

01:55:08.200 | from now

01:55:09.060 | of

01:55:09.820 | engineering

01:55:10.840 | ways

01:55:11.660 | of using

01:55:12.440 | them,

01:55:12.680 | of creating

01:55:13.400 | wormholes

01:55:14.000 | and using

01:55:14.660 | them for

01:55:15.580 | transportation

01:55:16.180 | of human

01:55:16.940 | like

01:55:17.180 | organisms?

01:55:17.780 | I think

01:55:19.060 | wormholes

01:55:19.420 | are a

01:55:19.740 | perfectly

01:55:20.100 | valid

01:55:20.680 | construction

01:55:21.520 | to

01:55:21.800 | consider.

01:55:22.220 | They're

01:55:23.800 | just a

01:55:24.640 | curve in

01:55:25.020 | space-time.

01:55:25.740 | Topologically,

01:55:28.960 | which has to

01:55:29.480 | do with the

01:55:29.820 | connectedness of

01:55:30.640 | the space,

01:55:31.100 | is a little

01:55:31.500 | tricky because

01:55:32.200 | we know that

01:55:33.000 | Einstein's

01:55:34.140 | description is

01:55:34.700 | completely in

01:55:35.520 | terms of

01:55:35.960 | local curves

01:55:36.840 | and

01:55:37.200 | distortions,

01:55:38.220 | expansion,

01:55:38.700 | contraction,

01:55:39.200 | but it

01:55:40.080 | doesn't say

01:55:40.440 | anything about

01:55:40.900 | the global

01:55:41.500 | connectedness of

01:55:42.380 | the space

01:55:42.900 | because he

01:55:43.720 | knew that

01:55:44.240 | it could

01:55:44.640 | be globally

01:55:45.560 | connected on

01:55:46.620 | the largest

01:55:47.180 | scales.

01:55:47.860 | This kind of

01:55:48.960 | origami that

01:55:49.580 | we're talking

01:55:49.980 | about,

01:55:50.300 | that you

01:55:50.700 | could travel

01:55:51.220 | in a

01:55:51.500 | straight line

01:55:52.100 | through the

01:55:53.080 | universe,

01:55:53.420 | leave our

01:55:54.180 | galaxy behind,

01:55:55.000 | watch the

01:55:55.740 | Virgo cluster

01:55:56.620 | drift behind

01:55:57.780 | us and travel

01:55:58.500 | in a straight

01:55:58.840 | line as

01:55:59.140 | possible and

01:55:59.600 | find ourselves

01:56:00.120 | coming back

01:56:00.740 | again to

01:56:01.640 | the Virgo

01:56:02.040 | cluster and

01:56:02.640 | eventually the

01:56:03.560 | Milky Way and

01:56:04.120 | eventually the

01:56:04.580 | Earth,

01:56:04.800 | that we could

01:56:05.480 | find ourselves

01:56:06.040 | on a

01:56:06.400 | connected,

01:56:06.980 | compact

01:56:08.180 | space-time.

01:56:08.740 | And so

01:56:09.160 | topologically,

01:56:10.360 | there's

01:56:12.260 | something we

01:56:13.200 | know for

01:56:13.560 | sure,

01:56:13.900 | something beyond

01:56:15.460 | Einstein's theory

01:56:16.080 | that has to

01:56:16.700 | explain that

01:56:17.360 | to us.

01:56:17.800 | Now,

01:56:18.740 | wormholes are

01:56:19.480 | a little

01:56:19.680 | funky because

01:56:20.300 | they're

01:56:20.500 | topological.

01:56:21.160 | They create

01:56:22.040 | these handles

01:56:22.720 | and holes

01:56:23.300 | and these

01:56:23.660 | sneaky,

01:56:24.100 | by topological

01:56:25.220 | I mean

01:56:25.620 | these connected

01:56:26.360 | spaces.

01:56:27.400 | Yeah,

01:56:28.520 | it's like

01:56:28.900 | Swiss cheese

01:56:29.980 | or something.

01:56:30.400 | Like Swiss

01:56:30.620 | cheese,

01:56:30.900 | right.

01:56:31.420 | So I

01:56:32.560 | could have

01:56:33.060 | two flat

01:56:35.460 | sheets that

01:56:36.460 | are connected

01:56:37.160 | by a wormhole

01:56:38.040 | but then wrap

01:56:38.680 | around on the

01:56:39.300 | largest scale,

01:56:39.860 | all this

01:56:40.500 | cool stuff.

01:56:42.240 | There's

01:56:42.700 | nothing wrong

01:56:43.420 | with it

01:56:43.880 | as far as

01:56:45.220 | I can see.

01:56:45.720 | There's

01:56:45.880 | nothing

01:56:46.160 | abusive

01:56:47.220 | towards the

01:56:47.980 | laws about

01:56:48.980 | a wormhole

01:56:49.560 | but we

01:56:50.340 | can reverse

01:56:50.980 | engineer.

01:56:51.400 | We were

01:56:51.900 | saying,

01:56:52.160 | oh look,

01:56:52.580 | if I

01:56:52.900 | know how

01:56:53.620 | matter and

01:56:54.020 | energy are

01:56:54.560 | distributed,

01:56:55.040 | I can

01:56:56.000 | predict how

01:56:56.440 | space-time is

01:56:56.980 | curved.

01:56:57.240 | I can

01:56:57.620 | reverse

01:56:57.920 | engineer.

01:56:58.300 | I can

01:56:59.000 | say,

01:56:59.140 | I want

01:56:59.580 | to build

01:57:00.020 | a curved

01:57:00.780 | space-time

01:57:01.280 | like a

01:57:01.580 | wormhole.

01:57:01.980 | What

01:57:02.700 | matter and

01:57:03.120 | energy do

01:57:03.540 | I need

01:57:03.820 | to do

01:57:04.140 | that?

01:57:04.440 | It's a

01:57:05.160 | simple

01:57:05.460 | process and

01:57:06.460 | it's

01:57:06.700 | kind of

01:57:06.900 | thing Kip

01:57:07.220 | Thorne

01:57:07.580 | worked on,

01:57:09.080 | very

01:57:09.340 | imaginative,

01:57:10.180 | creative

01:57:10.540 | person.

01:57:11.060 | The problem

01:57:13.540 | was that he

01:57:14.100 | said,

01:57:14.280 | oh,

01:57:14.680 | here's the

01:57:15.860 | bummer.

01:57:16.200 | The matter

01:57:17.880 | and energy

01:57:18.400 | you need

01:57:19.060 | doesn't seem

01:57:19.980 | to be like

01:57:20.420 | anything we've

01:57:20.920 | ever seen

01:57:21.240 | before.

01:57:21.580 | It has to

01:57:22.140 | have negative

01:57:22.940 | energy.

01:57:23.540 | That's not

01:57:25.400 | great.

01:57:26.980 | There are

01:57:27.580 | some

01:57:27.820 | conjectures

01:57:28.460 | that we

01:57:28.960 | shouldn't

01:57:29.240 | allow

01:57:29.560 | things

01:57:30.060 | that

01:57:30.900 | have

01:57:31.260 | that

01:57:31.560 | kind

01:57:31.740 | of

01:57:31.820 | a

01:57:31.920 | property

01:57:32.220 | that

01:57:32.400 | have

01:57:32.560 | negative

01:57:32.920 | energies.

01:57:33.540 | Only things

01:57:34.860 | that have

01:57:35.080 | positive

01:57:35.500 | energies

01:57:35.980 | are going

01:57:37.600 | to be

01:57:37.780 | stable

01:57:38.260 | and long

01:57:39.680 | lived.

01:57:39.960 | But we

01:57:40.280 | actually know

01:57:40.820 | of quantum

01:57:41.220 | examples of

01:57:41.780 | negative

01:57:42.040 | energy.

01:57:42.420 | It's not

01:57:43.380 | that crazy.

01:57:43.940 | There's

01:57:45.040 | something called

01:57:45.400 | the Casimir

01:57:45.940 | effect.

01:57:46.360 | You have

01:57:46.760 | two metal

01:57:47.180 | plates and

01:57:47.820 | put them

01:57:48.460 | really close

01:57:48.960 | together.

01:57:49.340 | You can

01:57:49.760 | see this

01:57:50.300 | kind of

01:57:50.600 | quantum

01:57:51.240 | fluctuation

01:57:52.040 | between the

01:57:52.580 | plates.

01:57:52.860 | It's called

01:57:53.160 | a Casimir

01:57:53.660 | energy and

01:57:54.260 | that can

01:57:55.060 | have a

01:57:55.560 | negative

01:57:55.800 | energy.

01:57:56.240 | It can

01:57:56.960 | actually

01:57:57.360 | cause the

01:57:58.920 | place to

01:57:59.180 | attract or

01:57:59.560 | repel

01:57:59.880 | depending on

01:58:00.560 | how they're

01:58:01.320 | configured.

01:58:01.740 | You could

01:58:03.060 | imagine doing

01:58:04.580 | something like

01:58:05.380 | that,

01:58:05.660 | having

01:58:06.420 | wormholes

01:58:07.840 | propped

01:58:08.340 | up by

01:58:09.540 | these kinds

01:58:10.100 | of quantum

01:58:10.640 | energies.

01:58:11.240 | People have

01:58:12.720 | thought of

01:58:13.300 | imaginative

01:58:14.080 | configurations

01:58:14.820 | to try to

01:58:15.720 | keep them

01:58:16.100 | propped up.

01:58:16.620 | Are we at

01:58:18.600 | the point of

01:58:19.180 | me saying,

01:58:19.660 | this is an

01:58:20.180 | engineering

01:58:20.560 | problem?

01:58:21.020 | I'm not

01:58:21.940 | saying that

01:58:22.360 | quite yet.

01:58:22.820 | But it's

01:58:23.780 | certainly

01:58:24.020 | plausible.

01:58:24.500 | Yeah,

01:58:25.980 | so you have

01:58:26.400 | to get a

01:58:26.740 | lot of

01:58:27.020 | this kind

01:58:27.380 | of weird

01:58:27.960 | matter.

01:58:29.400 | You need

01:58:30.740 | a lot of

01:58:31.140 | this weird

01:58:31.480 | matter to

01:58:31.860 | send a

01:58:32.120 | person

01:58:32.460 | through.

01:58:32.780 | Right.

01:58:34.100 | That's going

01:58:34.860 | to be

01:58:35.040 | really

01:58:35.280 | challenging.

01:58:35.540 | So I'm

01:58:36.380 | not saying

01:58:36.840 | it's simply

01:58:37.440 | an engineering

01:58:37.940 | problem,

01:58:38.380 | but it's

01:58:39.680 | all within

01:58:40.200 | the realm

01:58:40.760 | of plausible

01:58:42.180 | physics,

01:58:42.540 | I think.

01:58:43.200 | I think

01:58:44.000 | that's super

01:58:44.740 | interesting.

01:58:45.020 | I think it's

01:58:45.540 | obviously

01:58:45.860 | intricately

01:58:46.460 | and deeply

01:58:47.140 | connected to

01:58:47.660 | black holes.

01:58:48.160 | Is it

01:58:49.640 | fair to

01:58:50.160 | think of

01:58:50.800 | wormholes

01:58:51.220 | as just

01:58:51.680 | two black

01:58:52.240 | holes that

01:58:52.580 | are connected

01:58:53.020 | somehow?

01:58:54.160 | People have

01:58:54.540 | looked at

01:58:54.940 | that.

01:58:55.220 | They tend

01:58:56.020 | to be

01:58:56.220 | non-traversible

01:58:57.100 | wormholes.

01:58:57.760 | They're not

01:58:58.420 | trying to

01:58:58.740 | prop them

01:58:59.100 | open.

01:58:59.480 | But yeah,

01:59:01.440 | I mean,

01:59:01.920 | some of

01:59:02.760 | this ER

01:59:04.580 | equals

01:59:04.880 | EPR,

01:59:05.280 | quantum

01:59:05.680 | entanglement,

01:59:06.280 | they're trying

01:59:07.740 | to connect

01:59:08.300 | black holes.

01:59:11.240 | know,

01:59:11.480 | you know,

01:59:11.520 | it's really

01:59:12.700 | cool.

01:59:13.100 | It's not

01:59:13.660 | quite,

01:59:13.900 | again,

01:59:14.140 | it's not

01:59:14.460 | quite

01:59:14.660 | following

01:59:15.140 | the

01:59:15.360 | chalk,

01:59:15.740 | and by

01:59:16.080 | that I

01:59:16.360 | mean we

01:59:16.620 | can't

01:59:16.920 | exactly

01:59:17.340 | start at

01:59:17.880 | a concrete

01:59:18.240 | place,

01:59:18.680 | calculate all

01:59:19.920 | the way to

01:59:20.480 | the end

01:59:20.820 | yet.

01:59:21.080 | So if I

01:59:22.400 | may read

01:59:23.020 | off some

01:59:23.340 | of the

01:59:23.500 | ideas that

01:59:23.900 | Kip Thorne has

01:59:24.420 | had about

01:59:24.940 | how to

01:59:25.280 | artificially

01:59:25.760 | construct

01:59:26.300 | wormholes.

01:59:27.100 | So the

01:59:27.420 | first method

01:59:27.920 | involves

01:59:28.280 | quantum

01:59:28.620 | mechanics

01:59:29.100 | and the

01:59:29.380 | concept

01:59:29.620 | of

01:59:29.820 | quantum

01:59:30.140 | foam,

01:59:30.720 | and this

01:59:31.340 | is the

01:59:31.580 | thing

01:59:31.720 | we've been

01:59:32.020 | talking

01:59:32.340 | about.

01:59:32.700 | Now,

01:59:33.300 | to create

01:59:34.040 | a wormhole,

01:59:34.640 | these tiny

01:59:35.220 | wormholes

01:59:35.680 | would need

01:59:36.180 | to be

01:59:36.560 | enlarged

01:59:37.320 | and stabilized

01:59:38.120 | to be

01:59:38.960 | useful for

01:59:39.600 | travel,

01:59:40.100 | but the

01:59:41.140 | exact method

01:59:41.880 | of doing

01:59:42.340 | this remains

01:59:42.920 | entirely

01:59:43.300 | theoretical.

01:59:43.800 | No shit,

01:59:44.460 | you think so?

01:59:45.060 | So these

01:59:46.120 | tiny wormholes

01:59:47.560 | that are

01:59:47.860 | basically

01:59:48.460 | for the

01:59:50.320 | quantum

01:59:50.580 | entanglement

01:59:51.480 | of the

01:59:51.840 | particles,

01:59:52.260 | somehow

01:59:53.060 | enlarged.

01:59:53.980 | Man,

01:59:55.860 | playing with

01:59:56.420 | the topology

01:59:57.000 | of the

01:59:57.320 | Swiss cheese

01:59:57.860 | would be

01:59:58.740 | so interesting.

01:59:59.560 | Even to

02:00:01.360 | get a hint,

02:00:02.120 | that would

02:00:03.840 | be top

02:00:04.900 | three,

02:00:05.260 | if not

02:00:05.740 | one of,

02:00:06.180 | maybe even

02:00:06.820 | number one

02:00:07.300 | question for

02:00:07.800 | me to ask,

02:00:08.400 | if I got a

02:00:09.460 | chance to

02:00:09.880 | ask an

02:00:10.760 | omniscient

02:00:11.200 | being of

02:00:12.340 | a question

02:00:13.680 | that I can

02:00:14.020 | get answered

02:00:14.500 | to,

02:00:14.840 | maybe with

02:00:16.240 | some

02:00:16.400 | visualization,

02:00:17.040 | like the

02:00:19.260 | topology of

02:00:20.340 | the universe.

02:00:20.880 | Yeah.

02:00:22.540 | But I need

02:00:24.080 | some details.

02:00:24.900 | Right.

02:00:25.720 | I'll get

02:00:26.340 | an answer

02:00:26.860 | that I

02:00:27.340 | can't

02:00:27.680 | possibly

02:00:28.080 | comprehend.

02:00:28.600 | Right.

02:00:29.580 | It's a

02:00:30.380 | hyperbolic

02:00:30.800 | manifold

02:00:31.160 | that's

02:00:31.480 | identified

02:00:31.840 | across,

02:00:32.220 | yeah,

02:00:32.600 | exactly.

02:00:33.040 | You need

02:00:34.540 | to be able

02:00:34.840 | to ask a

02:00:35.280 | follow-up

02:00:35.700 | question.

02:00:36.000 | Yeah,

02:00:37.840 | that would

02:00:38.140 | be so

02:00:38.420 | interesting.

02:00:38.760 | Anyway,

02:00:39.100 | classical

02:00:40.320 | quantum

02:00:40.680 | strategy,

02:00:41.100 | the second

02:00:41.500 | approach

02:00:41.840 | combines

02:00:42.240 | classical

02:00:42.600 | physics

02:00:42.960 | with

02:00:43.140 | quantum

02:00:43.380 | effects.

02:00:44.160 | This

02:00:44.720 | method

02:00:46.040 | would

02:00:46.260 | require

02:00:47.000 | an

02:00:47.200 | advanced

02:00:47.540 | civilization

02:00:47.860 | to

02:00:48.140 | manipulate

02:00:48.560 | quantum

02:00:48.940 | gravity

02:00:49.300 | effects in

02:00:50.140 | ways we

02:00:50.400 | don't yet

02:00:50.720 | understand.

02:00:51.100 | There's a lot

02:00:51.640 | of...

02:00:52.100 | In ways

02:00:52.440 | we don't

02:00:52.740 | understand.

02:00:53.140 | Yeah,

02:00:53.360 | there's a lot

02:00:53.920 | of...

02:00:54.160 | And then there's

02:00:54.680 | exotic matter

02:00:55.580 | requirements.

02:00:56.040 | There's a lot

02:00:56.580 | of...

02:00:56.660 | But I can tell

02:00:57.260 | you,

02:00:57.580 | I'm pretty

02:00:58.800 | sure all of

02:00:59.480 | them have in

02:01:00.060 | common the

02:01:00.560 | feature that

02:01:01.640 | they're saying,

02:01:02.440 | here's what I

02:01:03.560 | want my wormhole

02:01:04.300 | to look like

02:01:04.880 | first.

02:01:05.260 | So it's like

02:01:06.420 | saying,

02:01:06.600 | I want to

02:01:06.920 | build a

02:01:07.220 | building first.

02:01:08.040 | So they

02:01:08.420 | construct,

02:01:10.880 | there's an

02:01:11.440 | architecture of

02:01:12.360 | the space

02:01:12.680 | time that

02:01:14.200 | they're after.

02:01:15.220 | And then they

02:01:16.360 | reverse the

02:01:17.140 | Einstein equations

02:01:17.960 | to say,

02:01:18.700 | what must

02:01:19.640 | matter in

02:01:20.060 | energy?

02:01:20.440 | What are the

02:01:21.880 | conditions that

02:01:22.620 | I impose on

02:01:23.540 | matter and

02:01:23.980 | energy to

02:01:24.560 | build this

02:01:25.180 | architecture?

02:01:25.780 | Which is

02:01:26.320 | unfortunately a

02:01:27.020 | very early

02:01:27.720 | step of

02:01:28.920 | figuring out

02:01:29.700 | things.

02:01:29.740 | Right.

02:01:29.980 | But it's

02:01:30.580 | important because

02:01:31.180 | it's how they

02:01:31.700 | realized, oh,

02:01:32.440 | wow, they have

02:01:32.940 | to have these

02:01:33.260 | negative energies,

02:01:33.940 | they have to

02:01:34.420 | violate certain

02:01:35.240 | energy conditions

02:01:37.140 | that we often

02:01:37.620 | assume are

02:01:38.140 | true.

02:01:38.580 | And then you

02:01:40.100 | either say,

02:01:40.920 | oh, well,

02:01:41.380 | then all bets

02:01:42.820 | are off,

02:01:43.140 | they'll never

02:01:43.560 | exist, or you

02:01:45.560 | look a little

02:01:47.060 | harder and you

02:01:47.680 | say, well, I

02:01:48.080 | can violate that

02:01:48.860 | energy condition

02:01:49.560 | without it being

02:01:50.180 | that big a

02:01:50.840 | deal.

02:01:51.020 | And again,

02:01:53.440 | quantum mechanics

02:01:54.080 | often does

02:01:54.860 | violate those

02:01:55.600 | energy conditions.

02:01:56.340 | So do you

02:01:57.060 | think the

02:01:57.360 | studying of

02:01:57.760 | black holes and

02:01:58.860 | some of the

02:01:59.240 | topics we've

02:01:59.680 | been talking

02:02:00.020 | about will

02:02:00.540 | allow us to

02:02:01.460 | travel faster

02:02:03.260 | than the speed

02:02:03.760 | of light or

02:02:04.280 | travel close to

02:02:05.000 | the speed of

02:02:05.520 | light or do

02:02:06.140 | some kind of

02:02:06.760 | really innovative

02:02:07.480 | breakthroughs on

02:02:08.520 | the propulsion

02:02:09.180 | technology we

02:02:09.960 | use for

02:02:10.940 | traveling in

02:02:11.660 | space?

02:02:11.960 | Yeah, I mean,

02:02:12.620 | sometimes I assign

02:02:13.560 | in an advanced

02:02:14.200 | general relativity

02:02:14.960 | class the

02:02:15.940 | assignment of

02:02:16.580 | inventing a

02:02:17.380 | warp drive.

02:02:17.940 | And it's kind

02:02:19.240 | of similar.

02:02:19.680 | So the idea

02:02:20.600 | is here's a

02:02:22.380 | place you want

02:02:22.860 | to get to

02:02:23.340 | and can you

02:02:25.260 | contract the

02:02:26.180 | space-time

02:02:26.820 | between you

02:02:28.300 | with some

02:02:29.800 | kind of

02:02:31.060 | something antithetical

02:02:32.300 | to dark

02:02:32.720 | energy, the

02:02:34.120 | opposite, and

02:02:35.500 | skip across

02:02:36.360 | and then push

02:02:37.740 | it back out

02:02:38.180 | again.

02:02:38.400 | That's all,

02:02:40.240 | you can do

02:02:41.060 | that in the

02:02:41.420 | context of

02:02:42.020 | general relativity.

02:02:42.760 | Now, I can't

02:02:44.880 | find the energy

02:02:45.800 | that has these

02:02:46.660 | properties, but I

02:02:47.260 | also can't find

02:02:47.840 | dark energy.

02:02:48.400 | So we've

02:02:50.100 | already been

02:02:50.500 | confronted with

02:02:51.180 | something that we

02:02:52.940 | look at the

02:02:53.540 | space-time, the

02:02:54.640 | space-time is

02:02:55.340 | expanding ever

02:02:56.660 | faster, we say

02:02:58.240 | what could

02:02:58.600 | possibly do that?

02:02:59.920 | we don't know

02:03:00.480 | what it is, but

02:03:01.000 | I can tell you

02:03:01.600 | about its

02:03:02.000 | pressure, I can

02:03:03.180 | tell you certain

02:03:03.860 | features about

02:03:04.620 | it, and I

02:03:05.960 | just call it

02:03:06.400 | dark energy, but

02:03:07.300 | I actually have

02:03:07.740 | no idea.

02:03:08.260 | It's just, that

02:03:08.860 | name's just a

02:03:09.440 | proxy for what

02:03:10.300 | this, it should

02:03:10.760 | be called

02:03:11.080 | invisible, because

02:03:11.820 | it's not actually

02:03:12.360 | dark, it's in

02:03:13.300 | this room, it's

02:03:13.840 | not hard to see

02:03:14.960 | through, it's

02:03:15.260 | not dark, it's

02:03:15.920 | literally

02:03:16.700 | invisible.

02:03:17.180 | So maybe that

02:03:18.900 | was a misnomer,

02:03:19.500 | but the point

02:03:20.340 | being, I still

02:03:21.540 | don't fundamentally

02:03:22.080 | know what it

02:03:22.580 | is, that's not

02:03:24.100 | so terrible, that's

02:03:24.880 | the state of the

02:03:25.660 | world that we're

02:03:26.000 | actually in.

02:03:26.600 | So maybe

02:03:27.580 | warp drive is

02:03:28.180 | just kind of

02:03:28.620 | like a version

02:03:29.200 | of that, I

02:03:29.780 | don't know what

02:03:30.680 | form of matter

02:03:31.340 | can do that

02:03:31.880 | yet, but at

02:03:33.520 | least I can

02:03:34.000 | identify the

02:03:34.860 | features that

02:03:35.460 | are needed.

02:03:35.900 | So figuring out

02:03:36.960 | what dark energy

02:03:37.920 | is might land

02:03:39.380 | some clues.

02:03:40.100 | Yeah, it

02:03:41.020 | actually, it

02:03:41.540 | might.

02:03:41.780 | It is positive

02:03:44.600 | energy, and a

02:03:47.540 | negative pressure,

02:03:48.420 | which is kind of

02:03:49.220 | like a rubber

02:03:49.680 | band sort of

02:03:50.480 | quality, we think

02:03:51.260 | of pressure as

02:03:51.720 | pushing things

02:03:52.260 | outward, and dark

02:03:53.640 | energy has a

02:03:54.120 | very strange

02:03:54.760 | sort of quality

02:03:55.500 | that as

02:03:56.320 | things move

02:03:56.760 | outward, you

02:03:57.380 | feel more

02:03:58.000 | energy, as

02:03:58.900 | opposed to

02:03:59.220 | less energy.

02:03:59.760 | The energy

02:04:00.160 | doesn't get

02:04:00.540 | lower, it

02:04:01.000 | gets more.

02:04:01.540 | So it doesn't

02:04:03.820 | have the right

02:04:04.640 | features for the

02:04:05.300 | wormhole, but

02:04:05.860 | those are some

02:04:06.320 | pretty surprising

02:04:07.040 | features.

02:04:07.820 | We again can

02:04:10.100 | conjecture like,

02:04:11.900 | oh hey, you

02:04:12.580 | know, the

02:04:12.940 | quantum energy

02:04:13.580 | of the vacuum

02:04:14.160 | kind of behaves

02:04:14.860 | that way.

02:04:15.340 | That would be a

02:04:16.240 | great resolution

02:04:17.080 | to the dark

02:04:17.900 | energy problem.

02:04:18.520 | It's just the

02:04:19.080 | energy of empty

02:04:19.680 | space, and it's

02:04:20.840 | the quantum energy

02:04:21.560 | of empty space.

02:04:22.260 | That's an excellent

02:04:23.140 | answer.

02:04:23.940 | The problem

02:04:24.440 | is, by all

02:04:26.320 | our methods, and

02:04:27.660 | all the

02:04:28.140 | understanding we

02:04:28.740 | have, that

02:04:29.520 | energy is either

02:04:30.780 | really, really

02:04:31.660 | huge, huge, way

02:04:35.160 | bigger than what

02:04:36.080 | we see today, or

02:04:37.060 | it's like zero.

02:04:37.800 | So that's a

02:04:39.980 | numbers problem.

02:04:41.140 | We can't

02:04:41.980 | naturally fine

02:04:43.920 | tune the energy

02:04:45.340 | of empty space

02:04:46.080 | to give us this

02:04:46.760 | really weird value

02:04:47.860 | so that we just

02:04:48.440 | happen to be

02:04:49.020 | seeing it today.

02:04:49.760 | But, again, we

02:04:52.000 | can think of a

02:04:52.680 | kind of dark

02:04:53.220 | energy that

02:04:53.700 | exists.

02:04:54.300 | So the question

02:04:55.420 | is just, why

02:04:55.960 | is it such a

02:04:58.360 | weird value, not

02:05:01.200 | how is this

02:05:02.020 | conceivable, because

02:05:03.460 | we can't conceive

02:05:04.100 | of it.

02:05:04.380 | Yeah, but if it's

02:05:05.060 | a weird value, that

02:05:06.020 | means there is a

02:05:06.820 | phenomenon we

02:05:07.420 | don't understand.

02:05:08.140 | Yes, there's

02:05:09.100 | absolutely a

02:05:09.820 | phenomenon.

02:05:10.080 | Nobody's going

02:05:10.960 | to say they're

02:05:11.680 | happy with that.

02:05:12.260 | We're all going

02:05:13.080 | to say there's

02:05:13.480 | something we don't

02:05:13.980 | understand, which

02:05:15.080 | is why we look

02:05:15.660 | to the extra

02:05:16.140 | dimensions, because

02:05:16.900 | then you can

02:05:17.700 | say, oh, maybe

02:05:18.320 | it has to do with

02:05:18.820 | the size of the

02:05:19.500 | extra dimensions, or

02:05:20.360 | the way that they're

02:05:20.960 | wrapped up.

02:05:22.260 | And so maybe

02:05:23.540 | it's foisted on

02:05:25.040 | us because of

02:05:26.140 | the topology, the

02:05:27.820 | connectedness of the

02:05:28.980 | higher dimensional

02:05:29.860 | space.

02:05:30.260 | These are all things

02:05:31.020 | that we're

02:05:31.260 | exploring.

02:05:31.640 | Nobody's landed

02:05:32.860 | one that's so

02:05:34.100 | compelling that your

02:05:36.700 | friends like it as

02:05:37.320 | much as you do.

02:05:37.800 | What do you think

02:05:40.860 | would lead to the

02:05:41.480 | breakthroughs on dark

02:05:42.460 | matter and dark

02:05:43.060 | energy?

02:05:43.920 | I think dark

02:05:44.760 | matter might

02:05:46.700 | be less

02:05:49.520 | peculiar than

02:05:52.340 | dark energy.

02:05:52.740 | My hope is that

02:05:53.680 | they're all tied

02:05:54.120 | together.

02:05:54.580 | That would be very

02:05:56.200 | gratifying.

02:05:56.760 | These aren't just

02:05:57.920 | separate problems

02:05:58.880 | coming from different

02:06:00.040 | sectors, but that

02:06:01.380 | they're actually

02:06:02.100 | connected.

02:06:02.940 | That the reason

02:06:05.520 | the dark matter is

02:06:06.260 | where it is in

02:06:07.820 | terms of how much

02:06:08.660 | it's contributing

02:06:09.300 | everything to

02:06:10.160 | the universe is

02:06:11.620 | connected with why

02:06:13.140 | the dark energy is

02:06:14.020 | showing up right

02:06:14.560 | now.

02:06:14.760 | I would love that.

02:06:15.480 | That would be a

02:06:16.620 | solution like no

02:06:17.460 | other, right?

02:06:18.440 | And like I said,

02:06:19.440 | if it revealed

02:06:20.600 | something about dark

02:06:21.580 | dimensions, you

02:06:22.320 | know, that would be

02:06:23.940 | a happy day.

02:06:24.680 | Correct me if I'm

02:06:25.580 | wrong.

02:06:25.680 | Dark matter can be

02:06:27.080 | localized in space.

02:06:28.380 | Yeah.

02:06:28.600 | Dark matter is

02:06:29.620 | localized in space,

02:06:30.520 | so it clumps.

02:06:31.180 | I mean, it doesn't

02:06:32.120 | clump a lot, you

02:06:33.100 | know, but I mean,

02:06:34.060 | it's around the

02:06:34.700 | galaxy.

02:06:35.080 | It's in a halo

02:06:36.380 | around the galaxy.

02:06:37.180 | So people get

02:06:38.120 | increasingly more

02:06:39.040 | confident that it

02:06:39.900 | doesn't think.

02:06:40.140 | Oh, it's really

02:06:40.840 | compelling.

02:06:41.340 | Yeah.

02:06:41.940 | I mean, you see

02:06:43.320 | these images of

02:06:46.400 | galaxies that

02:06:48.180 | clusters that pass

02:06:49.540 | through each other,

02:06:50.300 | and you can see

02:06:51.660 | where the light is,

02:06:52.560 | the luminous matter

02:06:53.560 | is distributed,

02:06:54.100 | and then by looking

02:06:55.720 | at the gravitational

02:06:56.740 | lensing, which

02:06:57.820 | shows you where

02:06:59.740 | the actual mass

02:07:00.700 | is distributed,

02:07:01.400 | so that light

02:07:02.420 | bends around the

02:07:03.500 | most massive parts

02:07:04.460 | in a particular way,

02:07:05.380 | so you can

02:07:05.780 | reconstruct where

02:07:06.960 | the mass is

02:07:07.580 | gravitationally,

02:07:08.520 | quite separate from

02:07:10.360 | looking at the

02:07:11.120 | luminous matter,

02:07:11.980 | which is not dark,

02:07:13.600 | and they are

02:07:14.420 | separate, because

02:07:16.560 | the stuff as they

02:07:17.380 | pass through each

02:07:18.000 | other, the

02:07:18.680 | interacting stuff,

02:07:19.760 | the luminous stuff

02:07:20.880 | collides and gets

02:07:22.580 | stuck, and you can

02:07:23.760 | see it colliding

02:07:24.680 | and lighting up.

02:07:25.320 | The dark stuff,

02:07:26.520 | which by definition

02:07:27.780 | it's dark because

02:07:28.580 | it doesn't

02:07:29.000 | interact, passes

02:07:30.540 | right through each

02:07:32.300 | other, right?

02:07:32.840 | And this is, I

02:07:34.180 | mean, it's so

02:07:34.700 | compelling.

02:07:35.140 | And there's lots

02:07:35.820 | of other observations,

02:07:38.160 | but that one is

02:07:39.760 | just, before you

02:07:40.720 | just look at it,

02:07:41.700 | you can see that

02:07:43.560 | the mass is

02:07:44.840 | distributed differently

02:07:45.960 | than the

02:07:47.040 | interacting luminous

02:07:48.240 | matter.

02:07:48.560 | So dark energy

02:07:49.920 | is harder to get

02:07:50.860 | a hold of.

02:07:51.400 | Dark energy is

02:07:52.060 | much harder to get

02:07:52.640 | a hold of.

02:07:54.240 | but, you know,

02:07:54.920 | I mean, the

02:07:55.800 | Higgs field could

02:07:56.680 | have also explained

02:07:57.560 | dark energy.

02:07:58.420 | If you've heard

02:07:59.860 | of the God

02:08:00.900 | particle, I don't

02:08:01.680 | know if you know

02:08:02.160 | the, originally

02:08:03.720 | Leon Letterman

02:08:04.600 | co-authored a book

02:08:05.880 | and he wanted to

02:08:06.640 | call it the

02:08:07.020 | goddamn particle

02:08:07.720 | because they

02:08:08.040 | couldn't find it.

02:08:08.720 | And his publisher

02:08:10.940 | convinced him to

02:08:12.000 | call it the God

02:08:12.580 | particle.

02:08:12.980 | And he said,

02:08:15.180 | he said they

02:08:16.280 | managed to offend

02:08:17.380 | two groups,

02:08:18.180 | those that believed

02:08:19.100 | in God and those

02:08:19.760 | that didn't.

02:08:21.320 | He was very

02:08:23.860 | funny.

02:08:24.200 | He was very

02:08:25.040 | witty.

02:08:25.260 | So, you know,

02:08:26.220 | Higgs turned out

02:08:26.900 | to be...

02:08:28.100 | Higgs, great

02:08:29.020 | discovery.

02:08:29.580 | I mean,

02:08:30.100 | unbelievable.

02:08:30.780 | There it was,

02:08:32.680 | build this massive

02:08:33.920 | collider in CERN

02:08:35.740 | in Switzerland and

02:08:36.380 | there it is.

02:08:36.900 | Unbelievable.

02:08:37.820 | Kind of where you

02:08:38.700 | expect it to be.

02:08:39.460 | Now, the reason I

02:08:41.020 | say it could be

02:08:42.140 | dark energy is

02:08:43.440 | because the Higgs

02:08:45.120 | particle, like a

02:08:46.420 | particle of light,

02:08:47.140 | also has a field,

02:08:48.260 | like an

02:08:48.860 | electromagnetic field.

02:08:50.440 | So, light can

02:08:51.000 | have this field

02:08:52.020 | that's distributed

02:08:52.740 | through all space,

02:08:53.740 | electric magnetic

02:08:54.660 | field, and you

02:08:55.520 | shake it around

02:08:56.240 | and it creates

02:08:56.880 | little particles.

02:08:57.440 | So, the Higgs

02:08:58.480 | field is actually

02:09:00.180 | more important

02:09:00.800 | than the Higgs

02:09:01.300 | particle, the

02:09:02.760 | complement to the

02:09:03.460 | Higgs particle,

02:09:04.000 | because that's

02:09:04.980 | what you and I

02:09:05.800 | connect with to

02:09:07.400 | get mass in our

02:09:09.000 | atoms.

02:09:09.480 | So, the idea is

02:09:10.760 | that our atoms

02:09:12.000 | are interacting with

02:09:12.960 | this gooey field

02:09:14.460 | that's everywhere.

02:09:15.320 | And that's what's

02:09:18.020 | giving us this

02:09:18.660 | experience of

02:09:19.280 | inertial mass.

02:09:20.220 | but we don't

02:09:20.940 | actually, there's

02:09:21.760 | not a lot of

02:09:22.180 | quanta lying

02:09:22.820 | around, there's

02:09:23.300 | not a lot of

02:09:23.680 | Higgs particles

02:09:24.340 | lying around,

02:09:24.900 | because they

02:09:25.200 | decay.

02:09:25.520 | So, it's the

02:09:26.860 | field that's

02:09:27.340 | really important,

02:09:27.840 | and that field

02:09:28.760 | could act like

02:09:30.140 | a dark energy.

02:09:30.800 | It's just not

02:09:32.460 | in the right

02:09:34.180 | place, meaning

02:09:35.220 | it's not at

02:09:36.520 | the right, the

02:09:37.440 | energy's too

02:09:38.000 | high to explain

02:09:39.720 | this tiny, tiny

02:09:40.600 | value today.

02:09:41.340 | And, again, we're

02:09:42.820 | back to this

02:09:43.340 | mismatch.

02:09:43.760 | It's not that we

02:09:44.360 | can't conceive of

02:09:45.500 | forms of dark

02:09:46.340 | energy, it's that

02:09:47.780 | we can't make

02:09:48.600 | one where

02:09:49.500 | we're finding

02:09:50.500 | it.

02:09:50.760 | So, I

02:09:52.300 | wonder if you

02:09:52.640 | can comment on

02:09:53.240 | something that

02:09:53.740 | I've heard

02:09:54.800 | recently.

02:09:55.240 | There's some

02:09:56.260 | people who say,

02:09:57.080 | people outside of

02:10:00.060 | physics, say that

02:10:01.100 | dark matter and

02:10:01.880 | dark energy is just

02:10:02.640 | something physicists

02:10:03.500 | made up.

02:10:04.320 | to put a label on

02:10:06.940 | the fact that

02:10:07.440 | they don't

02:10:07.940 | understand a

02:10:10.000 | very large

02:10:10.860 | fraction of the

02:10:11.780 | universe and how

02:10:12.600 | it operates.

02:10:13.200 | Is there some

02:10:14.040 | truth to that?

02:10:14.700 | What's your

02:10:15.120 | response to that?

02:10:15.680 | There's some

02:10:16.280 | truth to it, but

02:10:17.060 | it's really missing

02:10:18.160 | a huge point, which

02:10:19.340 | is that if we did

02:10:20.180 | not understand the

02:10:21.160 | universe as

02:10:21.720 | incredibly precisely

02:10:22.700 | as we do, it's

02:10:24.000 | stunning that there's

02:10:24.960 | modern precision

02:10:26.820 | cosmology.

02:10:27.520 | It's absolutely

02:10:28.720 | incredible.

02:10:29.860 | When COBE, which is

02:10:31.900 | an experiment that

02:10:32.720 | measured the light

02:10:33.540 | left over from

02:10:34.340 | the Big Bang in

02:10:36.000 | the 80s, first

02:10:37.480 | revealed its

02:10:38.500 | observations, I

02:10:39.400 | mean, there was

02:10:40.360 | applause, you know?

02:10:41.580 | People were cheering,

02:10:43.260 | right?

02:10:43.900 | It was unbelievable.

02:10:45.420 | We had predicted

02:10:46.440 | and measured the

02:10:48.160 | light left over from

02:10:49.100 | the Big Bang.

02:10:49.640 | And because of all

02:10:52.180 | the precision that's

02:10:52.920 | happened since then,

02:10:53.880 | that's how we're

02:10:55.640 | able to confront

02:10:56.800 | that there's things

02:10:58.140 | that we don't know.

02:10:58.800 | And that's how we're

02:10:59.660 | able to confront

02:11:00.280 | like, wow, this is

02:11:01.100 | really everything,

02:11:02.900 | everybody has ever

02:11:03.880 | seen and ever

02:11:05.500 | will see as far as

02:11:06.440 | we understand, makes

02:11:07.740 | up less than 5% of

02:11:09.320 | what's out there.

02:11:09.920 | And so I would say,

02:11:12.240 | yes, we're just

02:11:13.340 | giving proxy names to

02:11:14.380 | things we don't

02:11:14.880 | understand.

02:11:15.380 | But to dismiss that

02:11:16.980 | as some kind of, oh,

02:11:18.520 | they just don't know,

02:11:19.480 | it is actually quite the

02:11:20.940 | opposite.

02:11:21.300 | It is a stunning

02:11:22.540 | achievement to be able

02:11:23.400 | to stare that down

02:11:24.460 | and to have that so

02:11:27.280 | precise and so

02:11:28.240 | compelling that we're

02:11:29.000 | able to know that

02:11:32.160 | there's dark energy

02:11:33.120 | and dark matter.

02:11:33.740 | I don't think those

02:11:34.600 | are disputed anymore.

02:11:35.660 | And they were up

02:11:37.460 | until, you know,

02:11:38.460 | recently.

02:11:39.000 | They were still

02:11:39.680 | disputed.

02:11:40.140 | I think we're still

02:11:41.340 | at such early stages

02:11:42.500 | where we're not

02:11:44.100 | really even at a

02:11:44.980 | good explanation,

02:11:45.820 | right?

02:11:46.520 | You've mentioned a

02:11:47.300 | few.

02:11:47.540 | Well, I can think of

02:11:48.920 | examples of dark

02:11:49.860 | matter that exist that

02:11:51.160 | we really know for

02:11:52.080 | sure are real

02:11:53.080 | versions of dark

02:11:53.960 | matter, like

02:11:54.340 | neutrinos.

02:11:54.880 | Right now, they're

02:11:55.780 | radiating through us.

02:11:57.000 | That's very well

02:11:59.160 | confirmed.

02:11:59.580 | And they're technically

02:12:00.880 | dark.

02:12:01.320 | They don't interact

02:12:02.640 | with light.

02:12:03.500 | And so we can't see

02:12:05.020 | them.

02:12:05.280 | Right now, they're

02:12:05.940 | raining through us.

02:12:06.620 | If we could see the

02:12:08.240 | dark matter in this

02:12:09.340 | room where we

02:12:09.860 | absolutely know is

02:12:10.940 | coming from the sun,

02:12:11.900 | it would be wild.

02:12:12.920 | It would be a

02:12:13.900 | rainstorm, you know?

02:12:15.400 | But they're just

02:12:16.360 | invisible to us.

02:12:17.260 | Mostly, they pass

02:12:18.980 | through our bodies.

02:12:19.500 | Mostly, they pass

02:12:20.500 | through the Earth.

02:12:21.660 | Occasionally, they

02:12:22.180 | get caught in some

02:12:23.040 | fancy detector

02:12:24.320 | experiment that

02:12:25.240 | somebody built

02:12:25.900 | specifically to

02:12:27.300 | catch solar

02:12:27.780 | neutrinos.

02:12:28.420 | So, dark matter

02:12:29.800 | is known to

02:12:30.800 | exist.

02:12:31.280 | It's just, again,

02:12:33.120 | there's not enough

02:12:34.600 | of it.

02:12:34.960 | It's not the right

02:12:35.660 | mass to be the

02:12:37.520 | dark matter that

02:12:38.640 | makes up this

02:12:39.380 | missing component.

02:12:40.440 | I wanted to say

02:12:41.840 | that I've been

02:12:42.520 | recently fascinated

02:12:43.380 | by the flat Earth

02:12:44.180 | people because

02:12:45.940 | there's been a

02:12:46.720 | split in the

02:12:47.700 | community.

02:12:48.100 | First of all, the

02:12:50.760 | community is

02:12:51.140 | fascinating.

02:12:51.480 | study of human

02:12:52.160 | psychology, but

02:12:52.860 | they did

02:12:55.240 | this experiment

02:12:59.120 | where, I forgot

02:13:00.120 | who funded it,

02:13:00.920 | but they sent

02:13:02.180 | physicists and

02:13:04.540 | flat Earthers

02:13:05.140 | to Antarctica.

02:13:06.820 | Really?

02:13:08.440 | And this split

02:13:09.240 | happened because

02:13:09.860 | half of them got

02:13:10.540 | converted into

02:13:11.400 | round Earthers.

02:13:12.280 | Wow.

02:13:12.920 | Well, good for

02:13:13.520 | them.

02:13:13.740 | But then the

02:13:14.660 | other half just

02:13:15.360 | went that it was

02:13:16.280 | all a sigh out.

02:13:17.500 | Really?

02:13:18.140 | That's fascinating.

02:13:19.380 | Did somebody film

02:13:20.100 | that?

02:13:20.300 | That would be a

02:13:20.660 | great documentary.

02:13:21.320 | Yeah, it did.

02:13:21.820 | I did.

02:13:22.200 | I made a whole

02:13:22.740 | thing.

02:13:22.960 | This was just

02:13:23.600 | at the end of

02:13:24.660 | last year.

02:13:25.160 | There was a big

02:13:25.760 | meeting because I

02:13:27.340 | think that's such

02:13:28.400 | a clean study of

02:13:29.900 | conspiracy theories

02:13:30.780 | because there's so

02:13:32.780 | many conspiracy

02:13:33.280 | theories that have

02:13:34.040 | some inkling of

02:13:36.100 | truth in them.

02:13:37.720 | There's some

02:13:40.640 | elements about the

02:13:42.320 | way governments

02:13:42.820 | operate or

02:13:43.740 | human psychology

02:13:44.460 | that it's too

02:13:45.600 | messy.

02:13:46.200 | Flat Earthers to

02:13:47.360 | me is just

02:13:47.760 | clean.

02:13:48.340 | It's like

02:13:49.120 | spaghetti monster

02:13:49.940 | or something.

02:13:50.280 | It's just a

02:13:51.400 | cleanly wrong

02:13:52.640 | thing.

02:13:53.040 | It's a nice

02:13:53.760 | way to discuss

02:13:54.540 | how a large

02:13:56.440 | number of

02:13:56.840 | people can

02:13:57.960 | believe a

02:13:58.580 | thing.

02:13:58.860 | Yeah, and

02:13:59.640 | why do they

02:14:00.500 | want to believe

02:14:01.060 | a thing?

02:14:01.380 | What's very

02:14:02.200 | interesting is

02:14:04.140 | trying to use

02:14:06.220 | rational arguments.

02:14:07.500 | That makes it

02:14:08.940 | even more

02:14:09.620 | confounding to

02:14:10.800 | me.

02:14:10.920 | I would

02:14:11.280 | understand more

02:14:12.840 | somebody who

02:14:14.020 | just said,

02:14:14.380 | look, I have

02:14:14.780 | faith and I

02:14:15.240 | believe these

02:14:15.660 | things and it's

02:14:16.160 | not about reason

02:14:16.920 | and it's not

02:14:17.580 | about logic.

02:14:18.620 | Okay.

02:14:19.960 | I mean, I

02:14:22.000 | don't relate to

02:14:22.440 | it, but okay.

02:14:22.920 | But to say I'm

02:14:25.300 | going to use

02:14:25.800 | reason and logic

02:14:27.060 | and to prove

02:14:29.540 | to you this

02:14:30.560 | completely

02:14:31.220 | orthogonal

02:14:32.660 | conclusion, that

02:14:33.540 | I find really

02:14:34.160 | interesting.

02:14:34.560 | So there's some

02:14:35.240 | kind of romance

02:14:36.300 | about reason and

02:14:38.220 | logic?

02:14:38.600 | Yeah, but also

02:14:40.220 | there's a

02:14:41.160 | questioning of

02:14:42.260 | institutions.

02:14:42.740 | that's really

02:14:43.320 | interesting and

02:14:44.220 | important to

02:14:44.520 | understand.

02:14:44.860 | Well, I

02:14:45.620 | mean, I

02:14:46.800 | actually appreciate

02:14:49.180 | the skeptic's

02:14:51.360 | stance.

02:14:52.580 | I don't,

02:14:53.700 | scientists also

02:14:55.060 | have to be

02:14:55.500 | skeptics.

02:14:55.920 | We have to be

02:14:56.260 | childlike,

02:14:56.800 | naive, and

02:14:57.600 | somewhat, in

02:14:58.260 | some sense,

02:14:58.820 | really open to

02:15:00.100 | anything, right?

02:15:01.300 | Otherwise, you're

02:15:01.760 | not going to be

02:15:02.260 | a flexible, you're

02:15:03.360 | not going to be

02:15:03.700 | at the forefront,

02:15:04.140 | but also to be

02:15:05.960 | skeptical.

02:15:06.320 | So I have

02:15:08.840 | respect for it.

02:15:09.440 | I guess that's

02:15:10.200 | exactly what I'm

02:15:10.780 | saying is more

02:15:11.360 | confusing, because

02:15:12.700 | to invoke

02:15:14.320 | skepticism, and

02:15:15.820 | then to want to

02:15:16.620 | use rational

02:15:17.340 | argument, what

02:15:19.280 | is the other

02:15:20.220 | component that's

02:15:21.700 | going into this?

02:15:23.460 | Because as you

02:15:24.240 | said, this is

02:15:24.740 | something that's

02:15:25.240 | easily verified.

02:15:25.840 | I mean, we have

02:15:26.540 | people in space, so

02:15:28.100 | you have to believe a

02:15:28.880 | lot more machinery

02:15:30.280 | that's a lot more

02:15:34.100 | difficult to justify,

02:15:35.380 | explain, as a wild

02:15:37.900 | conspiracy.

02:15:38.340 | so there's

02:15:38.660 | something about

02:15:38.980 | the conspiracy

02:15:39.540 | that stirs a

02:15:41.320 | positive emotion.

02:15:42.420 | I think one of the

02:15:43.880 | most incredible

02:15:44.480 | things, I have to

02:15:45.220 | talk to you about

02:15:45.800 | this, one of the

02:15:46.500 | most incredible

02:15:46.980 | things that humans

02:15:47.660 | have ever accomplished

02:15:49.040 | is LIGO.

02:15:49.720 | We have to talk

02:15:53.040 | about gravitational

02:15:53.660 | waves, and the

02:15:55.100 | very fact that we're

02:15:56.020 | able to detect

02:15:56.640 | gravitational waves

02:15:57.560 | from the early

02:15:59.440 | universe is effing

02:16:01.680 | wild.

02:16:02.180 | It's crazy.

02:16:03.000 | Yeah.

02:16:03.960 | Can you explain

02:16:04.680 | what gravitational

02:16:05.620 | waves are?

02:16:06.320 | and we should

02:16:07.180 | mention you wrote

02:16:07.760 | a book about the

02:16:08.540 | humans, about the

02:16:10.400 | whole journey of

02:16:11.620 | detecting gravitational

02:16:12.680 | waves, and LIGO,

02:16:13.520 | Black Hole Blues is

02:16:15.220 | the book, but can you

02:16:16.080 | talk about gravitational

02:16:16.800 | waves and how we're

02:16:19.220 | able to actually do

02:16:20.560 | it?

02:16:20.780 | Let's just start with

02:16:21.660 | the idea of

02:16:22.060 | gravitational waves.

02:16:22.760 | I have to move

02:16:24.780 | around a lot of

02:16:25.460 | mass to make

02:16:26.780 | anything interesting

02:16:27.880 | happening in gravity.

02:16:28.620 | I mean, if you

02:16:29.000 | think about it,

02:16:29.560 | gravity is incredibly

02:16:30.480 | weak.

02:16:30.860 | I mean, right now,

02:16:31.340 | the whole Earth is

02:16:32.340 | pulling on me, and I

02:16:33.660 | can still get out of

02:16:34.320 | this chair and walk

02:16:35.200 | around.

02:16:35.920 | That's insane, the

02:16:37.280 | whole Earth.

02:16:38.020 | You know, gravity is

02:16:39.260 | weak, right?

02:16:40.660 | So, to get something

02:16:43.180 | going on in gravity, I

02:16:44.240 | need, like, big

02:16:44.900 | objects and things like

02:16:46.640 | black holes.

02:16:47.100 | So, the idea is if

02:16:48.760 | black holes curve space

02:16:50.240 | and time around them in

02:16:51.160 | the way that we've been

02:16:51.760 | describing, things fall

02:16:53.320 | along the curves in

02:16:54.000 | space.

02:16:54.240 | If the black holes move

02:16:55.620 | around, the curves have

02:16:57.600 | to follow them, right?

02:16:59.300 | But they can't travel

02:17:00.460 | faster than the speed of

02:17:01.600 | light either.

02:17:02.180 | So, what happens is if

02:17:03.780 | black holes, let's say,

02:17:04.980 | move around, maybe I've

02:17:05.740 | got two black holes in

02:17:06.700 | orbit around each other.

02:17:07.600 | That can happen.

02:17:08.300 | It takes a while.

02:17:09.820 | A wave is created in the

02:17:11.420 | actual shape of space, and

02:17:13.200 | that wave follows the

02:17:14.900 | black holes.

02:17:15.340 | Those black holes are

02:17:16.040 | undulating.

02:17:16.420 | Eventually, those two

02:17:18.120 | black holes will merge,

02:17:19.220 | and as we were talking

02:17:21.140 | about, it doesn't take an

02:17:22.120 | infinite time, even though

02:17:23.140 | there's time dilation,

02:17:23.920 | because they're both so

02:17:25.000 | big.

02:17:25.340 | They're really deforming

02:17:26.540 | space-time a lot.

02:17:28.060 | I don't have a little

02:17:28.760 | tidy marble falling across

02:17:30.280 | an event horizon.

02:17:30.860 | I have two event

02:17:31.600 | horizons, and in the

02:17:32.780 | simulations, you can see

02:17:33.780 | it bobble, and they

02:17:35.740 | merge together, and they

02:17:37.000 | make one bigger black

02:17:37.960 | hole, and then it

02:17:38.780 | radiates in the

02:17:39.800 | gravitational waves.

02:17:40.780 | It radiates away all

02:17:42.500 | those imperfections, and it

02:17:43.780 | settles down to one

02:17:45.240 | quiescent, perfectly silent

02:17:47.580 | black hole that's

02:17:48.940 | spinning.

02:17:49.220 | Beautiful stuff.

02:17:50.500 | And it emits E equals

02:17:51.640 | mc squared energy, so

02:17:52.980 | the mass of the final

02:17:54.400 | black hole will be less

02:17:56.180 | than the sum of the two

02:17:57.720 | starter black holes, and

02:17:59.720 | that energy is radiated

02:18:01.020 | away in this ringing of

02:18:02.280 | space-time.

02:18:02.840 | It's really important to

02:18:04.700 | emphasize that it's not

02:18:06.360 | light.

02:18:06.800 | None of this has to do

02:18:08.980 | literally with light that

02:18:11.480 | we can detect with normal

02:18:12.840 | things that detect light.

02:18:14.140 | X-rays form a light, gamma

02:18:15.840 | rays are a form of light,

02:18:16.740 | infrared, optical, this

02:18:18.740 | whole electromagnetic

02:18:19.920 | spectrum.

02:18:20.480 | None of it is emitted as

02:18:21.660 | light.

02:18:21.840 | It's completely dark.

02:18:22.680 | It's only emitted in the

02:18:24.320 | rippling of the shape of

02:18:25.180 | space.

02:18:25.440 | A lot of times it's likened

02:18:27.200 | closer to sound.

02:18:28.100 | Technically, we've kind of

02:18:29.300 | argued, I mean, I haven't

02:18:30.320 | done an anatomical

02:18:31.520 | calculation, but if you're

02:18:32.960 | near enough to two

02:18:34.520 | colliding black holes, they

02:18:35.720 | actually ring space-time in

02:18:37.100 | the human auditory range.

02:18:38.320 | The frequency is actually in

02:18:40.600 | the human auditory range

02:18:41.620 | that the shape of space

02:18:43.360 | could squeeze and stretch

02:18:44.860 | your eardrum, even in

02:18:45.940 | vacuum, and you could

02:18:47.560 | hear, literally hear these

02:18:49.100 | waves ringing.

02:18:50.140 | So the idea is that they're

02:19:03.460 | closer to something that you

02:19:07.120 | would want to map as a sound

02:19:09.800 | than it's something as a

02:19:10.700 | picture.

02:19:11.040 | Sorry.

02:19:11.480 | So what do you think it

02:19:12.760 | would feel like to ride the

02:19:15.460 | gravitational waves?

02:19:16.520 | So like to be, to exist, to

02:19:18.280 | exist.

02:19:18.700 | Because you mentioned

02:19:19.640 | your eardrums.

02:19:21.160 | It would literally bob around,

02:19:22.500 | like your orbit would change,

02:19:23.840 | right?

02:19:24.720 | If you were orbiting these

02:19:26.580 | black holes, two black holes,

02:19:28.000 | you'd be on a kind of

02:19:28.700 | complicated orbit.

02:19:29.600 | Yeah.

02:19:30.200 | but your orbit would get

02:19:31.580 | tossed about.

02:19:32.500 | How would the experience be

02:19:34.260 | because you're inside

02:19:35.220 | space-time?

02:19:35.980 | Yes, I see.

02:19:37.120 | So the black hole is

02:19:39.260 | experienced within space-time

02:19:40.640 | as a squeezing and

02:19:41.540 | stretching.

02:19:41.840 | So you would feel it as a

02:19:44.500 | sort of squeezing and

02:19:45.520 | stretching, and you would

02:19:46.200 | also find your location

02:19:47.280 | change.

02:19:47.760 | Where you would fall would

02:19:50.480 | be redirected.

02:19:51.420 | So it's literally like a

02:19:53.920 | squeezing and stretching.

02:19:55.240 | that's the way to think

02:19:56.000 | about it.

02:19:56.520 | And it's very detailed,

02:19:59.380 | the sort of nature of

02:20:02.300 | this.

02:20:02.600 | But for many years, people

02:20:05.320 | thought, well, these

02:20:06.300 | gravitational waves kind of

02:20:07.280 | have to exist for these

02:20:08.260 | intuitive reasons I've

02:20:09.260 | described as space-time's

02:20:10.340 | curved.

02:20:10.620 | I move the curve, the wave

02:20:12.240 | has to propagate through

02:20:14.560 | that curved space-time.

02:20:15.740 | But people didn't know if

02:20:16.940 | they really carried energy.

02:20:18.020 | The arguments went on and

02:20:19.480 | back and forth and papers

02:20:21.820 | written in decades, right?

02:20:24.060 | But I like this sound

02:20:26.720 | more than an analogy

02:20:28.300 | because I liken the black

02:20:30.200 | holes as like mallets on

02:20:31.540 | the drum.

02:20:31.920 | The drum is space-time.

02:20:33.680 | As they move, they bang

02:20:36.020 | on the drum of space-time

02:20:37.100 | and it rings.

02:20:38.660 | Remarkably, those

02:20:40.440 | gravitational waves, things

02:20:42.020 | don't interfere with them

02:20:43.100 | very much.

02:20:43.640 | So they can travel for

02:20:45.080 | two billion years, light

02:20:46.260 | years, you know, in

02:20:47.180 | distance, two billion years

02:20:48.660 | in time, and get to us

02:20:51.300 | kind of as they were when

02:20:53.160 | they were admitted.

02:20:53.600 | quieter, more diffuse.

02:20:56.020 | Maybe they've stretched out

02:20:57.820 | a little bit from the

02:20:58.800 | expansion of the universe,

02:20:59.540 | but they're pretty

02:21:01.320 | preserved.

02:21:01.880 | And so the idea of LIGO,

02:21:03.780 | this instrument, is to

02:21:05.800 | build a gigantic musical

02:21:07.560 | instrument.

02:21:08.100 | It's kind of like building

02:21:09.440 | an electric guitar, where

02:21:11.520 | the electric guitar is

02:21:12.940 | recording the shape of the

02:21:14.780 | string, and it plays it

02:21:16.320 | back to you through an

02:21:17.180 | amplifier.

02:21:17.700 | LIGO is trying to record the

02:21:20.300 | shape of the ringing

02:21:20.940 | drum.

02:21:22.100 | and they literally

02:21:23.020 | listen to it in the

02:21:23.820 | control room.

02:21:24.280 | Just sort of hums and

02:21:25.920 | wobbles.

02:21:26.320 | And they're like trying to

02:21:28.680 | play this recording drum

02:21:29.940 | back to you, as opposed to

02:21:31.540 | taking a snapshot, it's like

02:21:32.840 | in time.

02:21:33.680 | Yeah, but to construct this

02:21:34.840 | guitar...

02:21:35.780 | It has to be very large and

02:21:39.660 | extremely precise.

02:21:41.580 | It's unbelievable.

02:21:42.460 | I can't believe they

02:21:43.320 | succeeded.

02:21:43.740 | Honestly, I can't believe they

02:21:45.500 | succeeded.

02:21:45.780 | It was so insane.

02:21:47.320 | It was such a crazy thing to

02:21:49.840 | even attempt.

02:21:50.420 | It took them 50 years.

02:21:52.340 | Really, it's people who

02:21:53.560 | started in their 30s and 40s

02:21:55.320 | who were in their 80s when

02:21:57.240 | it succeeded.

02:21:58.240 | I mean, imagine that

02:21:59.240 | tenacity, the unbelievable

02:22:01.660 | commitment.

02:22:03.060 | But the sensitivity that

02:22:04.800 | we're talking about is we

02:22:05.660 | have this musical instrument,

02:22:07.640 | the four kilometers, spanning

02:22:10.420 | four kilometers in a kind of

02:22:11.780 | L shape with these tunnels

02:22:13.600 | where there's the largest

02:22:15.520 | holes in the Earth's

02:22:16.500 | atmosphere because they

02:22:17.440 | pulled a vacuum in these

02:22:18.540 | tunnels to build this

02:22:19.840 | instrument.

02:22:20.200 | And they're measuring,

02:22:22.760 | they're trying to record the

02:22:25.160 | wobbling of space-time,

02:22:26.260 | right, as it passes, this

02:22:27.580 | sort of undulation, that

02:22:30.360 | amounts to less than

02:22:32.660 | one ten-thousandth the

02:22:34.900 | variation in a proton over

02:22:37.700 | the four kilometers.

02:22:38.860 | It's an insane, insane

02:22:42.140 | achievement.

02:22:42.740 | I love great engineering.

02:22:44.380 | I don't know how they did

02:22:45.660 | it.

02:22:45.780 | I followed them around from

02:22:47.480 | so, just for fun, I'm very

02:22:50.260 | theoretical.

02:22:50.760 | I don't build things.

02:22:52.640 | I'm always super impressed

02:22:54.560 | that people can translate

02:22:56.380 | something on the page and it

02:22:58.900 | looks like wires and I don't

02:23:00.440 | know how, I'm always surprised

02:23:02.100 | at what it looks like.

02:23:03.180 | But I walked the tunnels with

02:23:05.720 | Ray Weiss, who won the Nobel

02:23:07.140 | Prize, along with Kip Thorne and

02:23:08.780 | Barry Barish, one of the project

02:23:09.980 | managers.

02:23:10.340 | And I walked the tunnels with

02:23:11.920 | Ray.

02:23:12.020 | It was a delight.

02:23:13.080 | I mean, Ray's one of the most

02:23:14.480 | delightful people.

02:23:15.120 | Kip is one of the most

02:23:15.980 | wonderful people I've ever

02:23:17.020 | known.

02:23:19.100 | And Ray said to me, you

02:23:21.240 | know, the reason why it was

02:23:21.900 | called Black Hole Blues is

02:23:23.080 | because about a month before

02:23:25.460 | they succeeded, he said to

02:23:27.880 | me, if we don't detect black

02:23:29.060 | holes, this whole thing's a

02:23:30.040 | failure.

02:23:30.340 | And we've led this country,

02:23:33.800 | you know, down this wrong

02:23:35.520 | path.

02:23:36.080 | And he really felt like this

02:23:38.500 | tremendous responsibility for

02:23:40.820 | this project to succeed.

02:23:42.140 | And it weighed on him, you

02:23:43.740 | know.

02:23:43.920 | It was just quite tremendous

02:23:47.360 | what the integrity, right, the

02:23:50.980 | scientific integrity.

02:23:51.800 | And the first instruments he

02:23:53.480 | built, he was building outside

02:23:55.020 | of MIT and on a tabletop.

02:23:57.420 | And his colleagues said, you're

02:23:59.280 | not going to get tenure.

02:23:59.980 | You're never going to succeed.

02:24:03.040 | And they just kept going.

02:24:05.440 | People like that, so huge

02:24:07.980 | teams, huge collaborations, are

02:24:11.960 | just, it's how the world moves

02:24:14.360 | forward because...

02:24:15.660 | It's an example.

02:24:16.780 | It's, you know, there's a

02:24:18.420 | building cynicism about

02:24:19.720 | bureaucracies when a large

02:24:21.480 | number of people, especially

02:24:22.420 | connected to government, can be

02:24:24.140 | productive.

02:24:24.640 | You know, bureaucracies slow

02:24:25.900 | everything down.

02:24:26.520 | So it's nice to see an

02:24:29.420 | incredibly unlikely,

02:24:30.600 | exceptionally difficult

02:24:32.220 | engineering project like this

02:24:33.800 | succeed.

02:24:34.300 | Oh, yeah.

02:24:34.900 | So I understand why there's

02:24:36.540 | this weight on the shoulders

02:24:37.600 | and I'm grateful that there's

02:24:40.120 | great leaders that push it

02:24:43.160 | forward like that.

02:24:44.020 | Yeah.

02:24:44.400 | It really is.

02:24:45.600 | You see so many moments when

02:24:48.160 | they could have stumbled.

02:24:48.840 | Yeah.

02:24:49.660 | And they built a first

02:24:51.160 | generation machine just after

02:24:52.700 | 2000.

02:24:53.300 | And it wasn't a surprise to

02:24:55.640 | them, but it detected nothing.

02:24:56.720 | Crickets.

02:24:57.260 | Mm-hmm.

02:24:58.100 | Crickets.

02:24:58.640 | And they just, you know, they

02:25:00.460 | have the wherewithal to keep

02:25:01.660 | going.

02:25:02.000 | Second generation.

02:25:03.320 | They're about to turn the

02:25:05.380 | machine on, quote unquote.

02:25:06.780 | You know, it's a little bit of a

02:25:07.760 | simplification, but do their first

02:25:09.160 | science run.

02:25:09.760 | And they decide to postpone

02:25:12.180 | because they feel they're not

02:25:14.540 | ready yet.

02:25:15.100 | It's September 14th in 2015.

02:25:17.200 | And the experimentalists are out

02:25:20.180 | there.

02:25:20.280 | They're in the middle of the

02:25:20.940 | night.

02:25:21.120 | You know, they're working all

02:25:21.920 | night long and they're banging

02:25:23.840 | on the thing, you know,

02:25:25.180 | literally driving trucks,

02:25:26.780 | slamming the brakes on to see

02:25:28.220 | the noise that it creates.

02:25:29.480 | And so they're really messing

02:25:31.400 | with the machine, really

02:25:32.260 | interfering with it just to kind

02:25:33.540 | of calibrate how much noise can

02:25:35.200 | this thing tolerate.

02:25:35.840 | And I guess the story is,

02:25:38.120 | is they get tired.

02:25:38.720 | There's an instrument in

02:25:39.960 | Louisiana and there's one in

02:25:40.960 | Washington state and they go

02:25:42.040 | home, put their tools down,

02:25:44.280 | they go home.

02:25:45.140 | It's, they leave the instrument

02:25:47.660 | locked though, mercifully.

02:25:49.220 | And it's something like within

02:25:51.640 | the span of an hour of them

02:25:52.740 | driving back to their humble

02:25:55.140 | abodes that they have in these

02:25:56.580 | remote regions where they built

02:25:58.840 | these instruments, this

02:26:01.420 | gravitational wave washes over.

02:26:03.060 | I think it hits Louisiana

02:26:04.280 | first and travels across

02:26:06.400 | the U S brings the instrument

02:26:09.060 | in Washington state.

02:26:09.920 | It began, you know, over a

02:26:12.360 | billion and a half years ago

02:26:13.620 | before multicellular organisms

02:26:15.560 | had emerged on the earth.

02:26:16.860 | Just imagine this from like a

02:26:19.600 | distant view, this collision

02:26:21.220 | course, right?

02:26:22.260 | And, um, it's the centenary.

02:26:25.320 | It's, it's, it's the year

02:26:26.660 | Einstein published general

02:26:28.760 | relativity.

02:26:29.200 | So it was this, you know, the

02:26:31.720 | a hundred years.

02:26:33.080 | I mean, just think about where

02:26:34.800 | that, where that signal was when

02:26:36.860 | Einstein in 1915 wrote down the

02:26:41.140 | general theory of relativity.

02:26:42.280 | It was on its way here.

02:26:43.160 | It was almost here.

02:26:45.080 | Uh, what do you think is cooler?

02:26:48.460 | Uh, Einstein's general relativity

02:26:51.920 | or LIGO?

02:26:55.520 | Well, I can't disparage my

02:26:57.340 | friends, but of course, relativity

02:26:59.000 | is just so all encompassing.

02:27:00.520 | No, but so hold on a second.

02:27:02.080 | All encompassing, super powerful

02:27:04.660 | leap of a theory.

02:27:06.660 | Yeah.

02:27:07.060 | And they built it.

02:27:09.420 | They built it.

02:27:10.580 | I don't know, man.

02:27:11.260 | The greatest engineering in the,

02:27:13.560 | you know, because I don't know

02:27:15.380 | because, you know, yeah, humans

02:27:17.880 | getting together and building the

02:27:19.480 | thing, that's really ultimately

02:27:20.880 | what, uh, what impacts

02:27:24.000 | the world, right?

02:27:24.920 | Yeah.

02:27:25.760 | Uh, I mean, I, I just, as I said,

02:27:28.560 | my admiration for, for Ray and

02:27:30.600 | Kip and the entire team is, is

02:27:32.440 | enormous and, you know, just

02:27:33.960 | imagining Ray had been out there

02:27:36.280 | on site.

02:27:36.940 | He had just left to go back

02:27:38.540 | home, um, wakes up in the middle

02:27:41.000 | of the night and sees it, you

02:27:42.100 | know, can you imagine?

02:27:43.260 | And there's a signal, you know,

02:27:45.620 | there's something in the log.

02:27:47.600 | He's like, what the hell is

02:27:48.660 | that?

02:27:48.900 | So speaking of the human

02:27:51.940 | story, you, uh, also wrote the

02:27:54.120 | book, A Mad Man Dreams of

02:27:55.160 | Turing Machines.

02:27:55.780 | It connects two geniuses of the

02:27:57.820 | 20th century, Alan Turing and

02:27:59.240 | Gertle.

02:27:59.500 | What specific threads connect

02:28:02.520 | these two minds?

02:28:03.460 | Yeah.

02:28:04.500 | I was, um, I was really

02:28:07.040 | mesmerized by these two

02:28:08.380 | characters.

02:28:08.820 | They, people know of Alan

02:28:11.160 | Turing for having ideated

02:28:13.960 | about the computer, being the

02:28:17.000 | person, to really imagine

02:28:19.360 | that.

02:28:19.600 | But his work began with

02:28:21.120 | thinking about Gödel's work.

02:28:22.820 | That's where it began.

02:28:24.260 | And it began with this

02:28:26.980 | phenomenon of undecidable

02:28:28.740 | propositions or unprovable

02:28:30.980 | propositions.

02:28:31.860 | So, um, uh, there was

02:28:35.020 | something huge that happened in

02:28:36.700 | mathematics.

02:28:37.100 | People imagined that any

02:28:39.320 | problem in math could

02:28:41.700 | technically be proven to be

02:28:43.000 | true.

02:28:43.280 | doesn't mean human beings

02:28:44.260 | are going to prove every

02:28:46.080 | fact about everything in

02:28:47.660 | mathematics, but, you know,

02:28:48.480 | it should be provable, right?

02:28:49.820 | I mean, it seemed kind of,

02:28:50.640 | it's not that wild

02:28:52.100 | supposition.

02:28:53.480 | And everyone believed this.

02:28:54.820 | All the great mathematicians,

02:28:55.680 | Hilbert was a call of his to

02:28:57.960 | prove that.

02:28:58.560 | And Gödel, a very strange

02:29:01.220 | character, uh, very unusual.

02:29:04.200 | He, he was a Platonist.

02:29:06.200 | He, he literally believed that

02:29:08.560 | mathematical objects had a

02:29:10.220 | existential reality.

02:29:12.360 | He wasn't so sure about this

02:29:13.660 | reality, this reality he

02:29:15.000 | struggled with.

02:29:15.680 | He, he was distrustful, um, a

02:29:18.880 | physical reality, but he

02:29:19.860 | absolutely took very seriously

02:29:21.480 | a Platonic reality and often

02:29:23.400 | his own way of thinking.

02:29:25.300 | And he proved that there were

02:29:27.600 | facts, even among the numbers

02:29:29.140 | that could never be proven to

02:29:31.300 | be true.

02:29:31.660 | To think about that, how wild

02:29:33.980 | that is, that even a fact

02:29:36.200 | about numbers seems very

02:29:38.700 | simple, uh, could be true and

02:29:41.780 | unprovable, could never exist as

02:29:44.580 | a theorem, for instance, in

02:29:46.480 | mathematics, unreachable.

02:29:47.660 | Um, this incompleteness result

02:29:51.440 | was very disturbing.

02:29:52.780 | Essentially, it's equivalent to

02:29:54.180 | saying there's no theory of

02:29:55.420 | everything for mathematics.

02:29:56.340 | It was very disturbing to people,

02:29:58.740 | but it was very profound.

02:30:00.000 | And Alan Turing got involved in

02:30:03.600 | this because he was, you know, he

02:30:06.080 | was thinking about uncomputable

02:30:07.320 | numbers.

02:30:07.980 | So, um, and that led him, what's

02:30:12.320 | an uncomputable number?

02:30:13.400 | A number like 0.175.

02:30:15.920 | It just goes on forever with no

02:30:17.640 | pattern.

02:30:18.020 | And I can't, I can't even figure out

02:30:20.860 | how to generate it.

02:30:21.560 | There's no rule for making that

02:30:23.660 | number.

02:30:23.980 | And he was able to prove that there

02:30:25.680 | were such things as these

02:30:26.500 | uncomputable, effectively unknowable

02:30:29.040 | numbers.

02:30:29.480 | And that might not sound like a big

02:30:31.220 | deal was actually, was actually

02:30:32.720 | really quite profound.

02:30:34.180 | He was relating to Godel

02:30:36.140 | intellectually, right?

02:30:37.740 | In the space of ideas.

02:30:39.040 | But he goes a very different

02:30:40.880 | path, almost philosophically the

02:30:43.060 | opposite direction.

02:30:43.960 | He, he, he builds, he starts to,

02:30:46.340 | to think about machines.

02:30:47.700 | He starts to think about

02:30:48.780 | mechanizing thought.

02:30:49.900 | He starts to think, what is a

02:30:51.420 | proof?

02:30:51.700 | How does a mathematician reason?

02:30:54.000 | What does it mean to reason at

02:30:54.980 | all?

02:30:55.100 | What does it mean to think?

02:30:55.940 | And he begins to imagine inventing

02:30:58.200 | a machine that will execute

02:31:02.440 | certain orders, you know,

02:31:04.820 | mechanized thought in a specific

02:31:06.520 | way.

02:31:06.880 | Well, maybe I can get a machine.

02:31:08.240 | I can imagine a machine that does

02:31:09.680 | this kind of thinking.

02:31:10.820 | And that he can prove that even a

02:31:12.920 | machine could not compute these

02:31:15.480 | uncomputable numbers.

02:31:16.400 | But where he ends up is the idea of

02:31:19.040 | a universal machine that computes,

02:31:21.440 | essentially can take different

02:31:24.360 | software and execute different jobs,

02:31:27.060 | right?

02:31:27.320 | we don't have a different computer

02:31:28.580 | to connect to the internet than we

02:31:30.780 | do to write papers.

02:31:32.020 | It's one machine and one piece of

02:31:35.700 | hardware, but it can do all of these,

02:31:37.540 | this huge variety of tasks.

02:31:40.420 | And so he really does invent the

02:31:42.140 | computer, essentially.

02:31:43.520 | And famously, he uses that thinking in

02:31:48.240 | a very primitive form in the war effort

02:31:50.900 | where he's recruited to help break the

02:31:54.000 | German Enigma code, which is heavily

02:31:57.540 | encrypted and largely believed to be

02:31:59.220 | uncrackable code.

02:32:00.220 | And people believe that Turing and his

02:32:04.480 | very small group actually turned the

02:32:06.480 | tide of the war in favor of the Allies

02:32:08.400 | precisely by using a combination of this

02:32:12.380 | thinking and just sheer ingenuity and some

02:32:14.660 | luck.

02:32:16.880 | But the other profound revelation that Turing has is that,

02:32:22.140 | well, maybe we're just machines, right?

02:32:25.400 | And just biological machines.

02:32:27.980 | And this is a huge shift for him.

02:32:30.060 | It feels very different from Godel, who doesn't really believe in reality

02:32:33.440 | and thinks numbers are platonic realities.

02:32:37.660 | And Turing kind of thinking, we're kind of like, we're actually machines and we

02:32:41.580 | could be replicated.

02:32:42.260 | So, of course, Turing's influence is still widely felt.

02:32:47.760 | On many levels.

02:32:48.860 | On many levels, yeah.

02:32:50.560 | In complexity theories, in theoretical computer science and mathematics, but also

02:32:54.480 | philosophy with his famous Turing test paper.

02:32:57.360 | So, like you said, conceiving, like, what is the connection that I guess

02:33:01.900 | Gerard never really made between mathematics and humanity Turing did?

02:33:07.960 | But I think there's another connection to those two people is that they're both

02:33:11.760 | in their own way kind of tormented humans.

02:33:14.560 | Yeah, I think they were very tormented.

02:33:16.080 | What aspect of that contributed to who they are and what ideas they developed?

02:33:23.300 | I mean, I think so much.

02:33:25.720 | I don't want to promote the kind of trite trope of the mad genius, you know,

02:33:35.540 | if you're brilliant, you are insane.

02:33:37.320 | I don't think that.

02:33:38.400 | I don't think if you're insane, you're brilliant.

02:33:40.300 | But I do think if somebody who's very brilliant, who also chooses not to go for

02:33:48.320 | regular gratification in life, they don't go for money, they don't necessarily value

02:33:55.880 | creature comforts, they're not leveraging for fame.

02:34:01.420 | I mean, they're really after something different.

02:34:03.920 | I think that can lead to a kind of runaway instability, actually, sometimes.

02:34:09.000 | So they're already outside of kind of social norms.

02:34:13.380 | They're already outside of normal connections with people.

02:34:16.760 | They've already made that break.

02:34:20.280 | And I think that makes them more vulnerable.

02:34:22.180 | So Gödel did have a wife and a strong relationship, as far as I understand, and was a successful

02:34:30.940 | mathematician and ended up at the Institute for Advanced Study, where he walked with Einstein

02:34:35.300 | to the Institute every day.

02:34:38.600 | And they talked about, and he proved certain really unusual things in relativity.

02:34:41.900 | You made reference to these rotating galaxies we were talking, and actually Gödel had a model

02:34:47.560 | of a rotating universe that you could travel backwards in time.

02:34:50.760 | It was mathematically correct.

02:34:52.560 | Showed Einstein that within relativity, you could time travel.

02:34:57.960 | He was just an unbelievably influential and brilliant man, but he was probably a paranoid schizophrenic.

02:35:05.100 | He did have breaks with reality.

02:35:08.740 | He was, I think, quite distrustful and feared the government, feared his food was being poisoned,

02:35:18.480 | and ultimately, literally starved himself to death.

02:35:23.000 | And it's such an extreme outcome for such a facile mind, for such a brilliant mind.

02:35:34.740 | I think it's important not to glorify romanticized madness or suffering, but to me, you flip that

02:35:42.560 | around and just be inspired by the peculiar maladies of a human mind, how they can be leveraged

02:35:50.700 | and channeled creatively.

02:35:52.720 | Oh, yeah.

02:35:53.620 | I think a lot of us, obviously, probably every human has those peculiar qualities.

02:35:59.120 | You know, I talk to people sometimes about just my own psychology, and I'm extremely self-critical.

02:36:08.740 | I'm drawn to the beauty in people, but because I make myself vulnerable to the world, I can

02:36:14.960 | really be hurt by people.

02:36:16.360 | And that thing, okay, you can lay that out, this particular human, okay?

02:36:20.420 | And, you know, there's a bunch of people that will say, well, many of those things you don't

02:36:27.460 | want to do.

02:36:28.340 | Maybe don't be so self-critical.

02:36:30.980 | Maybe don't be so open to the world.

02:36:33.840 | Maybe have a little bit more reason about how you interact with the outside world.

02:36:38.780 | It's like, yeah, maybe.

02:36:40.500 | Or maybe be that, and be that fully, and channel that into a productive life, into we're all going

02:36:47.420 | to die in the time we have on this earth.

02:36:50.920 | Make the best of the particular weirdness that you have.

02:36:58.740 | And maybe you'll create something special in this world.

02:37:01.520 | And in the end, it might destroy you.

02:37:03.360 | And I think a lot of these stories are that.

02:37:05.260 | It's not that.

02:37:05.900 | Oh, yeah.

02:37:06.560 | It's not like saying, oh, because in order to achieve anything great, you have to suffer.

02:37:13.200 | No.

02:37:13.620 | If you're already suffering, if you're already weird, if you're already somehow don't quite

02:37:20.320 | fit in your particular environment, in your particular part of society, use that somehow.

02:37:26.240 | Use the tension of that, the friction of that, to create something.

02:37:29.200 | I mean, that's what I, you know, Nietzsche, who suffered a lot from even like stupid stuff

02:37:36.240 | like stomach issues.

02:37:37.340 | Oh, yeah.

02:37:38.340 | That can be everything.

02:37:39.220 | All kinds of, right.

02:37:39.960 | Migraines.

02:37:40.900 | Psychosomatic or psychophysical, but.

02:37:44.100 | And all of a sudden, that's the real, it's like, that can somehow be channeled into a productive

02:37:52.460 | life.

02:37:52.900 | It should be inspiring.

02:37:54.160 | A lot of us suffer in different ways.

02:37:56.180 | Yeah.

02:37:56.360 | I'm a big believer in the tragic flaw, actually.

02:37:59.220 | I think the Greeks really had that right.

02:38:01.500 | You're describing it.

02:38:03.700 | What makes us great is ultimately our downfall.

02:38:06.420 | Maybe that's just inevitable.

02:38:08.220 | The choice could be not to be great.

02:38:12.560 | And I guess that's sort of what I mean by they had already broken from a traditional path because

02:38:19.300 | they decided to pursue something so elusive and that would isolate them to some extent inevitably

02:38:28.960 | and that could fail, right?

02:38:31.900 | And whose rewards were hard to predict even.

02:38:36.060 | And I do think that that all the character traits that went into their accomplishments were the same traits that went into their demise.

02:38:47.600 | And I think you're right.

02:38:49.060 | I think you're right.

02:38:49.920 | You could say, well, you know, Lex, maybe you should not be so empathetic.

02:38:53.860 | Hold yourself, cut yourself off a little bit.

02:38:56.560 | Protect yourself.

02:38:57.180 | Right.

02:38:57.840 | But isn't that exactly what you're bringing?

02:39:00.220 | One of the elements that you're bringing that makes something extraordinary in a space that lots of people try to break through.

02:39:07.340 | Yeah.

02:39:07.700 | And we should mention that for every girl on Turing, there's millions of people who have tried and who have destroyed themselves and without reason.

02:39:18.340 | I would find it impossible to not pursue a discovery that I could imagine my way through if I can really see how to get there.

02:39:31.460 | I cannot imagine abandoning it for some other reason, fear that it would be misused, which is real fear, right?

02:39:42.860 | I mean, it's a real concern.

02:39:44.800 | I don't think in my work, since I'm doing extra dimensions in the early universe or black holes, you know, I feel pretty safe.

02:39:51.560 | But, I mean, who knows, right?

02:39:54.540 | Bohr couldn't think of a way to use quantum mechanics to kill people.

02:39:58.240 | I cannot imagine pulling back and saying, nope, I'm not going to finish this.

02:40:04.380 | You know, I'll give you a common example of an exceptionally brilliant person, Terence Tao.

02:40:08.520 | Brilliant.

02:40:09.760 | Brilliant mathematician.

02:40:10.820 | Brilliant.

02:40:11.940 | He is better than, out of all the brilliant people I've ever met in the world, he's better than anybody else at working on a hard problem and then realizing when it's, for now, a little too hard.

02:40:25.900 | Oh, that I can do.

02:40:27.160 | Stepping away.

02:40:29.060 | Yeah.

02:40:29.560 | And he's like, okay, this is now a weekend problem.

02:40:32.580 | Uh-huh.

02:40:33.440 | Because he has seen too much, for him, everybody's different, but Grigori Perlman or Andrew Wiles, who give themselves fully, completely, for many years, over to a problem.

02:40:46.780 | Yes.

02:40:47.180 | And for every Grigori Perlman.

02:40:49.040 | And they might not have cracked it.

02:40:50.140 | Yep.

02:40:50.580 | So, you choose your life story.

02:40:53.420 | I totally agree.

02:40:54.340 | Now, I'm not going to say, sometimes I take too long to come to that conclusion, but I will proudly say, as most theoretical physicists should, that I kill most of my ideas myself.

02:41:05.260 | Okay.

02:41:05.940 | So, you're able to walk away.

02:41:07.000 | And that's, I am absolutely able to say, oh, that's just not, I mean, I'm not going to deny that sometimes I maybe take a while to come to that conclusion longer than I should, but I will.

02:41:18.100 | I absolutely will.

02:41:18.880 | I will drop it.

02:41:19.480 | And that is, that is, any self-respecting physicist should be able to do that.

02:41:24.380 | The problem is with somebody like Andrew Wiles, who you were describing, who, to prove Fermat's last theorem, it took him seven years.

02:41:32.020 | Was that the number?

02:41:32.740 | Something like that.

02:41:33.580 | He went up into his mother's attic or something and did not emerge for seven years.

02:41:38.740 | Is that maybe he did.

02:41:40.360 | He was on the right track.

02:41:41.160 | He wasn't wrong.

02:41:41.900 | And, but that's so, it could have been interminable.

02:41:44.660 | He still might not have gotten there in the end.

02:41:48.060 | And, and so that's the, the really difficult space to be in, uh, where you're not wrong.

02:41:54.160 | You are onto something, but it's just asymptotically approaching that solution and you're never actually going to land it.

02:42:02.180 | Um, that happens.

02:42:04.140 | And he had a really, I, it would break me, straight up break me.

02:42:08.020 | He had, he had a proof.

02:42:09.980 | Yes.

02:42:10.580 | He announced it and they, somebody found a mistake in it.

02:42:14.080 | That would just break me.

02:42:15.540 | Yeah.

02:42:15.840 | Because you, now everybody gets excited.

02:42:18.060 | Right.

02:42:18.840 | And now you, you, you realize that it's a failure and to go back.

02:42:22.820 | I mean, it was taking a year for people to check it.

02:42:24.480 | It's not the kind of thing you'd look over in an afternoon.

02:42:26.340 | And then to, to have the will, to have the confidence and the patience to go back.

02:42:31.600 | Unbelievable story.

02:42:32.580 | And to rigorously go through, work through it.

02:42:34.100 | It's a great story.

02:42:34.780 | But then there's another great story, Grigori Perlman, who, uh, spent seven years and turned

02:42:39.600 | down the Fields Medal.

02:42:40.500 | He did it all alone.

02:42:41.780 | And then after he turned down the Fields Medal and the Millennial Prize, proving the Porncare

02:42:46.760 | conjecture, he just walked away.

02:42:49.500 | Yeah.

02:42:50.040 | Now that's a very different psychology.

02:42:52.520 | Mm-hmm.

02:42:53.040 | That's wired differently.

02:42:54.080 | Doesn't care about money.

02:42:55.300 | Doesn't care about fame.

02:42:56.320 | Doesn't care about anything else.

02:42:57.560 | Yep.

02:42:58.140 | In fact, uh, in St. Petersburg, Russia, trying to, trying to get a conversation with him.

02:43:03.820 | It turns out when you walk away and you're a recluse and you enjoy that, you also don't

02:43:09.500 | want to talk to some weird dude in a tie.

02:43:11.700 | So it turns out I'm trying, I'm trying.

02:43:16.420 | Well, if you look at someone like Turing, his, his eccentricities were, were completely

02:43:23.180 | different, right?

02:43:24.340 | It's not as though there's some mold and I, I really don't like it when it's portrayed

02:43:28.520 | that way.

02:43:28.840 | These are really individuals who, um, who were still lost in their own minds, but in very

02:43:35.760 | different ways.

02:43:36.280 | And Turing was openly gay, really, um, during this time, you know, he was working during the

02:43:43.900 | war, World War II, so we understand the era.

02:43:47.220 | And it was illegal, um, in Britain, uh, at the time.

02:43:53.120 | And he kind of refused to conceal himself.

02:43:59.840 | Um, there was a time when the kind of attitude was, well, we're just going to ignore it.

02:44:06.960 | But he had been robbed by somebody that he had picked up somewhere.

02:44:13.000 | I think it was in Manchester and it was such a small thing.

02:44:15.660 | I don't know what they took.

02:44:16.700 | It took like nothing, you know, it was nothing, but he, he couldn't tolerate, he goes to the

02:44:23.020 | police and he tells them, and then he's arrested.

02:44:27.640 | He's the criminal because it involved this homosexual act.

02:44:31.740 | Now here you have somebody who made a major contribution to the allies winning the war.

02:44:39.340 | I mean, it's just unbelievable, not to mention the genius, mathematical genius.

02:44:45.440 | I mean, he saved the lives of the people that were doing this to him.

02:44:49.520 | And they essentially chemically castrated him as, as a punishment.

02:44:55.680 | That was his sentence.

02:44:57.040 | And he became very depressed and suicidal.

02:45:01.560 | And, um, the story is he was, he was obsessed with Snow White, which was recently released.

02:45:08.120 | And he used to chant one of the, uh, little, I don't know if you would call them poem songs, uh, dip the apple in the brew.

02:45:17.240 | Let the sleeping death seep through was a chant from Snow White.

02:45:21.520 | And, um, the, the belief is, is that he dipped, uh, an apple in cyanide and bit from the poison apple.

02:45:28.640 | Now, I don't know if this is apocryphal, but people think that the apple on the Macintosh with the bite out of it is a reference to Turing.

02:45:35.620 | Now, some people deny this.

02:45:36.900 | Lies, lies, lies, lies.

02:45:37.900 | Um, but, uh, some people say he did that so his mother could believe that maybe it was an accident.

02:45:45.660 | But, yeah, quite a terrible end.

02:45:48.220 | Yeah, but two of the greatest humans ever.

02:45:52.000 | Mm-hmm.

02:45:52.580 | I think the reason why, um, I, I tie them together, not just because ultimately their work is so connected, but, but because there's this sort of impossibility of understanding them, there's this sort of impossibility of proving something about their lives.

02:46:10.420 | That even if you try to write factual biography, there's something that eludes you, and I felt like that's kind of fundamental to the mathematics, the incompleteness, the undecidable, the uncomputable.

02:46:22.500 | So, structurally, it was, it was about what we can kind of know and what we can believe to be true, but can't ever really know.

02:46:31.560 | Yeah, limitations of formal systems, limitations of.

02:46:35.000 | Exactly.

02:46:35.080 | Biography, limitations of fiction and nonfiction.

02:46:39.040 | Limitations.

02:46:39.780 | So you, I mean, there's so many layers to you, so one of which there's this romantic notion of just understanding humans, exploring humans, and there's the exploring science, there's the exploring the very rigorous, detailed physics and cosmology of things.

02:46:56.640 | So, uh, there's, uh, there's the art, the kind of artistry, so I, I, I saw that you're the chief science officer of Pioneer Works, which is mostly like an artist type of situation.

02:47:05.740 | It's a place in Brooklyn.

02:47:06.840 | Can you explain to me what that is and what role does art play in your life?

02:47:12.840 | Yeah.

02:47:13.200 | I can start with Pioneer Works.

02:47:14.940 | Pioneer Works, in some sense, it was inevitable that I would land at Pioneer Works.

02:47:19.180 | So it felt like I was marching there for many years and, and just, it, it came together again, like at this collision.

02:47:25.200 | Um, it was founded by this artist, Dustin Yellen, very utopian idea.

02:47:29.180 | He bought this building, this old iron works factory called Pioneer Iron Works in, in Brooklyn.

02:47:34.200 | It was in complete disrepair, but a beautiful old, um, building, uh, from the late 1800s.

02:47:40.440 | And he wanted to make this kind of collage.

02:47:45.000 | Dustin's definitely a collage artist, works in glass, very big pieces, very imaginative and, and, and wild and narrative and into nature and consciousness.

02:47:55.500 | And, and I think he wanted to do that with people.

02:47:57.580 | He wanted a place of a collage, a living example of artists and scientists.

02:48:05.300 | And it was founded by Dustin and, and Gabriel Florence was the founding artistic director.

02:48:10.220 | Um, it, it was started just before Hurricane Sandy.

02:48:14.240 | I don't know if people feel as strongly about Hurricane Sandy as New Yorkers do, but it was a real moment around 2012, 2013.

02:48:20.220 | Sort of paused the project and you can even see the kind of water line on the brick of where Sandy was.

02:48:26.740 | I came in and collided with these two, uh, shortly after that.

02:48:32.460 | And it really was like a collision.

02:48:33.980 | I'm science, you know, they're art.

02:48:36.720 | Gabe makes everything, builds everything with his bare hands.

02:48:40.100 | Dustin's a dreamer.

02:48:41.160 | They love science.

02:48:42.580 | They really wanted science, but science is hard to access.

02:48:45.020 | Um, I have always loved the translation of science in literature, in art.

02:48:52.720 | Uh, I love fiction writers, like really literary fiction writers who dabble thinking about science.

02:48:58.480 | And I, I, I, I very firmly believe science is part of culture.

02:49:02.200 | I just, I know it to be true.

02:49:04.200 | I don't think of myself as doing outreach or education.

02:49:07.500 | I, I don't like those labels.

02:49:09.060 | I'm, I'm doing culture.

02:49:11.640 | An artist in their, uh, studio working out problems, understanding materials, building a body of work.

02:49:21.700 | Nobody says to them when they exhibit, why are you doing outreach or, uh, or are you doing education?

02:49:26.380 | You know, it's the logical extension.

02:49:28.840 | So I feel that if you've had the privilege of knowing some of these people or seeing a little bit from the summit, if you've had a little glimpse yourself that, that you bring it back to, to, to, to the world.

02:49:43.880 | So we, boom, exploded.

02:49:45.860 | Pioneerics became science and art.

02:49:48.660 | It's not artists who all do science or scientists who do art.

02:49:52.760 | It's real hardcore scientists talking about science and a lot of live events.

02:49:57.120 | We have a magazine called Broadcast where we feature all of the disciplines rubbing together, artists working on all kinds of things.

02:50:04.660 | When I first started doing events there, my, my first guest, um, like you, I was talking to people and this was like, I know how to talk to people because I know these guys.

02:50:12.980 | And I've been on the interviewee side so much.

02:50:16.660 | I know exactly.

02:50:17.520 | It was like fully formed for me, how to do those conversations.

02:50:20.360 | Yeah.

02:50:20.760 | You're extremely good at that also.

02:50:22.460 | Yeah.

02:50:22.900 | Thank you.

02:50:23.260 | I appreciate that.

02:50:24.100 | I, I, you learn how to do it too, though.

02:50:26.340 | I mean, I don't think the first one I did, I think I've learned, right.

02:50:29.100 | It, and you acquire, you get better, which is really interesting.

02:50:32.420 | Um, and I love to study.

02:50:34.160 | I think you do too.

02:50:34.960 | I really look into the material and that, and I, I love science.

02:50:39.700 | I really do.

02:50:40.440 | I want to talk to a CRISPR biologist because I don't understand it and I want to understand it.

02:50:45.720 | And I saw there's a bunch of cool events and very, very fascinating variety of humans.

02:50:51.220 | Yes.

02:50:52.200 | We have a really fascinating variety of humans.

02:50:54.600 | That's a good way of putting it.

02:50:56.940 | Yeah.

02:50:57.100 | So it made me put in my mental map of like, it's a cool place to go and visit when in New York.

02:51:02.980 | Yes.

02:51:03.780 | You have to come see us.

02:51:04.820 | I think you would love it.

02:51:06.460 | Also, I should mention fashion.

02:51:08.180 | I've seen you do a bunch of talks and there's, there's a lot of fashion.

02:51:11.280 | Oh yeah.

02:51:11.820 | Oh my God.

02:51:12.580 | Appreciation of fashion going on.

02:51:13.940 | I am so, you're giving me an opportunity to give a shout out, um, to Andrea Lauer, who's a designer who makes these amazing jumpsuits that I often wear.

02:51:24.940 | And a lot of my events, she has a jumpsuit, um, design line called Risen Division.

02:51:30.480 | And she just makes these incredible, they're fantastic.

02:51:33.040 | We also design patches for all of our events.

02:51:36.040 | So there are these string theory patches and consciousness patches.

02:51:38.980 | We should show this as overlays.

02:51:41.000 | Right.

02:51:41.320 | Hopefully there'll be nice pictures floating about everywhere.

02:51:44.740 | So, you know, I think all of this is, is just, I just like to experiment with life.

02:51:49.100 | I think making the magazine was a big, wild experiment.

02:51:51.660 | You said with life?

02:51:52.660 | With life.

02:51:53.300 | Nice.

02:51:53.840 | Yeah.

02:51:54.280 | Um, this kind of idea that we were just describing is, I, I, I find it hard to stop the momentum.

02:52:01.020 | If I think something can, I could make something, um, I have to try to make it.

02:52:08.020 | Um, and to me, this is the closest I come to experimentation and collaboration, because even though I collaborate theoretically, I have great collaborators, Brian Green, Massimo Peratti, Dan Cabot, these are my really close collaborators.

02:52:20.600 | Um, a lot of theoretical physics is alone, and you're in your mind a lot.

02:52:26.760 | Um, this is something that really was, was, was built, this triad of Dustin, Gabe, and I, and, and all the amazing people who work there on our amazing board.

02:52:36.940 | We really are doing it together.

02:52:38.240 | You take one element out and it starts to, um, it starts to change shape.

02:52:43.340 | And that's a very interesting experience, I think.

02:52:46.040 | And making things is an interesting experience.

02:52:49.220 | Since you mentioned literature, is there, is there books that had an impact on your life, whether it's literature, uh, fiction, nonfiction?

02:52:57.320 | Mm, I love fiction, which I think people expect me to read a lot of, sort of sci-fi or nonfiction.

02:53:03.680 | I mostly read fiction.

02:53:05.420 | I had a syllabus of great fiction writers that had science in it, and, um, I love that syllabus.

02:53:13.200 | Can you ever make that public or no?

02:53:15.500 | Yeah, I suppose I could, but I can tell you some of them as they come to mind.

02:53:18.780 | Um, Katsuo Ishiguro, who won the Nobel Prize, wrote Remains of the Day, probably most famously.

02:53:24.200 | Um, his book Never Let Me Go.

02:53:26.380 | It's unbelievable.

02:53:28.540 | Totally devastating.

02:53:30.140 | Stunning.

02:53:31.420 | I see, I really love literature.

02:53:33.760 | So when, when people can do that with these very abstract themes, um, it's sort of my favorite space for, for literature.

02:53:41.800 | Martin Amis wrote a book that runs backwards, Time's Arrow.

02:53:44.160 | I love some of his other books even more, but Time's Arrow is pretty clever.

02:53:48.440 | So you like it when, uh, these non-traditional mechanisms are applied to tell a story that's fundamentally human.

02:53:56.840 | Mm-hmm.

02:53:57.500 | That there's some.

02:53:58.260 | Yes.

02:53:58.680 | Some dramatic tragic.

02:54:00.440 | Like, I really appreciate that.

02:54:03.480 | Even Orwell is amazing.

02:54:06.300 | You know, Hitchens, writing on Orwell is amazing.

02:54:08.740 | Um, there was, there were some plays on the syllabus.

02:54:13.500 | I have to think of what else was in there, but there was one book that I think was kind of surprising that I think is an absolute masterpiece, which is The Road.

02:54:20.680 | And you might say, in what sense is The Road a science?

02:54:23.160 | Well, first of all, Cormac McCarthy absolutely loves scientists and science.

02:54:27.100 | And you can feel this very subtle influence in that book is, um, it's, it's a really remarkable, uh, precise, stunning, ethereal, all of these things at once.

02:54:41.960 | And there's no who, what, where, when, or how.

02:54:45.120 | Um, you might guess it's a nuclear event that kicks off the book, or a lot of people know The Road, I think, from the movie, but really the book is magnificent.

02:54:54.940 | Um, and it's very, very abstract, but there's a sense to me in which it is, science is structuring.

02:55:01.040 | And still, fundamentally, that book is about the human story, the human connection.

02:55:05.800 | Yeah, absolutely, the boy.

02:55:06.140 | Yeah, so the science plays a role in creating the world.

02:55:10.000 | Mm-hmm.

02:55:10.460 | And within it, there's still, really, it's a, it's a, it's a different way to explore human dynamics in a way that's, maybe, lands some clarity and depth.

02:55:22.780 | That maybe a more direct telling of the story will not, yeah.

02:55:27.660 | And even surreal worlds that, I mean, to me, I don't know why, but, um, I return to Orwell's Animal Farm a lot.

02:55:35.020 | And it's these kind of like, it's another art form to be able to tell a simple story with some surreal elements.

02:55:42.760 | Mm-hmm.

02:55:43.560 | Yeah.

02:55:44.520 | Orwell, just simple language.

02:55:46.020 | Mm-hmm.

02:55:46.540 | Oh, Animal Farm's incredible.

02:55:48.180 | And in fact, some of the, uh, I've kind of played with, you know, some animals are more equal than others.

02:55:53.520 | There are, there are, in Godel Turing's work, there were some infinities that are bigger than others.

02:55:58.480 | Yeah, there's, there's certain books just kind of inject themselves into our culture in a way that just reverberates and, uh, I don't know, hasn't, creates culture.

02:56:12.400 | Not just, like, influences, it's just like, it's quite incredible how writing and literature can do that.

02:56:19.060 | Yeah.

02:56:19.380 | If you could have one definitive answer to one single question, this is the thing I mentioned to you.

02:56:24.640 | Oh, this is so hard.

02:56:25.120 | Yeah.

02:56:25.500 | Well, there's a, there's an oracle, and you get to talk to that oracle.

02:56:29.940 | You can ask multiple questions, but it has to be on that topic.

02:56:33.560 | So, just clarify, what, what mystery of, of the universe would you want that oracle to help you with?

02:56:40.280 | You know, it's funny, I should say the obvious thing, and, but I feel like, I almost feel like it would be greedy.

02:56:45.880 | I think of a complicated response to this.

02:56:49.040 | The obvious thing for me to say would be, I want to understand quantum gravity, or if gravity's emergent.

02:56:54.800 | It's not even something I work on day to day.

02:56:58.600 | You know, I, I mostly just look with interest at what others are doing, and if I think I can jump in, I would, but I'm not jumping into the fray.

02:57:05.860 | But, obviously, that's the big, that's the big one.

02:57:09.220 | And, and there is a sort of sense that with that will come the answers to all these other things.

02:57:13.860 | My complicated relationship is that, well, you know, part of the scientific disposition isn't having stuff you don't know the answer to.

02:57:22.620 | I mean, we're not going to have all the answers, I hope, because then, sort of, then what?

02:57:27.480 | Right?

02:57:28.780 | It's sort of dystopian.

02:57:29.900 | I totally agree with you.

02:57:31.140 | There's some, I like the mysteries we have.

02:57:34.000 | Yeah.

02:57:34.300 | I kind of had this assumption that there will always be mysteries, so you'll want to keep solving them.

02:57:39.900 | Right.

02:57:40.040 | They will lead to more.

02:57:41.040 | In the same way that relativity led to black holes, black holes led to the information loss paradox, or the Big Bang, or what happened before, or the multiverse.

02:57:50.500 | It's because we learned so much, we were able to escalate to the next level of abstraction.

02:57:55.160 | Yeah, by the way, we should mention that if you're talking to this oracle, and even if you ask the obvious question about quantum gravity, I almost guarantee you with 100% probability that even if all your questions are answered, it's impossible to get to the end of your questions.

02:58:12.560 | Right.

02:58:13.280 | It says, you know, the oracle will say, no, you can't unify.

02:58:18.780 | Then you say, well, what?

02:58:19.980 | Well, yeah, yeah, yeah.

02:58:20.700 | And then you say emergent, and then the oracle will say, well, everything you think is fundamental is not.

02:58:27.260 | It's emergent.

02:58:27.940 | It's like, okay, well, this is, we need to, this is more questions.

02:58:32.220 | That's right.

02:58:32.800 | I mean, it's been 100 years more since relativity, and we're still picking it apart.

02:58:37.240 | Yeah.

02:58:38.080 | No.

02:58:39.580 | And there will be, there may be new ones.

02:58:41.740 | Mm-hmm.

02:58:42.120 | You write that eventually all our history in this universe will be erased.

02:58:46.780 | Mm-hmm.

02:58:47.640 | How does that make you feel?

02:58:48.720 | Yeah, it's a tough thought.

02:58:51.760 | But again, I think there's a way in which we can come to terms with that, that that's kind of poetic.

02:58:58.220 | You know, you build something in the sand, and then you erase it.

02:59:05.540 | So I think it's just a reminder that we have to be concerned about our immediate experience too, right?

02:59:14.060 | How we are to those around us, how they are to us, what we leave behind in the near term, what we leave behind in the long term.

02:59:24.700 | Have we contributed, and did we, you know, did we contribute overall net positive?

02:59:31.660 | Eventually, I think it's kind of hard to imagine.

02:59:39.140 | But yes, all of these Nobel Prizes, all of these mathematical proofs, all of these conversations, all of these ideas, all the influence we have on each other, even the AI, eventually, will expire.

02:59:52.740 | Well, at the very least, we can focus on drawing something beautiful in the sand before it's washed away.

02:59:59.960 | Well, this was an incredible conversation.

03:00:03.040 | I'm truly grateful for the work you do.

03:00:04.880 | And me for your work.

03:00:06.480 | Thanks so much for having me.

03:00:07.680 | Thank you for talking today.

03:00:08.680 | Yeah, lots of fun.

03:00:11.120 | Thanks for listening to this conversation with Jan 11.

03:00:13.200 | To support this podcast, please check out our sponsors in the description.

03:00:17.180 | And now, let me leave you with some words from Albert Einstein on the topic of relativity.

03:00:23.380 | When you're courting a nice girl, an hour seems like a second.

03:00:29.860 | When you sit on a red-hot cinder, a second seems like an hour.

03:00:34.080 | That's relativity.

03:00:36.620 | Thank you for listening, and hope to see you next time.

03:00:41.220 | Thank you.

03:00:41.380 | Thank you.

03:00:42.000 | Thank you.

03:00:43.000 | Thank you.

03:00:44.000 | Thank you.

03:00:45.000 | Thank you.

03:00:46.000 | Thank you.

Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468

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