The Science of Interstellar with Christopher Nolan

Unravel the mysteries of Interstellar when Neil deGrasse Tyson interviews filmmaker and auteur Christopher Nolan. In-studio, Eugene Mirman and cosmologist Dr. Janna Levin help keep the conversation down-to-earth.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:18Neil deGrasse Tyson?

  I'm your host, Neil deGrasse Tyson. I'm an astrophysicist at the American Museum of Natural History's Hayden Planetarium. And I've got with me my co-host Eugene Mirman. Eugene, thanks for being here.

• 0:29Eugene Mirman?

  Hello, it's great to be here.

• 0:31Neil deGrasse Tyson?

  Give me some love for Eugene. I'm your host, Neil deGrasse Tyson. I'm an astrophysicist at the American Museum of Natural History's Hayden Planetarium. And I've got with me my co-host Eugene Mirman. Eugene, thanks for being here.

• 0:45Eugene Mirman?

  Hello, it's great to be here.

• 0:46Neil deGrasse Tyson?

  Give me some love for Eugene. Yeah. Eugene, professional comedian. And your voice on Bob's Burgers.

• 0:53Eugene Mirman?

  Yeah.

• 0:53Neil deGrasse Tyson?

  Yeah, yeah, you get around.

• 0:55Eugene Mirman?

  I do, I do. I do at least two things. Maybe more.

• 1:00Neil deGrasse Tyson?

  So, so, thanks for doing this. We're like on TV now.

• 1:03Eugene Mirman?

  I know.

• 1:03Neil deGrasse Tyson?

  It's good.

• 1:04Eugene Mirman?

  Very exciting.

• 1:04Neil deGrasse Tyson?

  He fixed up. Normally, we do this on the radio and he's unshaven, he's a little sloppy. I've never seen the guy this neat.

• 1:09Eugene Mirman?

  Yeah, I have a claw for a hand, but look. It's science.

• 1:14Neil deGrasse Tyson?

  Today, you know what our topic is? Science fiction. Science fiction movies. Have you got any favorite movies?

• 1:19Eugene Mirman?

  I do have, I love, well, one, I love science fiction. But I'd say a lot of superhero movies, Star Trek.

• 1:26Neil deGrasse Tyson?

  Oh, superhero. You want to be a superhero.

• 1:28Eugene Mirman?

  Well, I don't know that I want, I don't want, I don't want the responsibility.

• 1:32Neil deGrasse Tyson?

  Oh, okay. It is a big responsibility to be a superhero.

• 1:36Eugene Mirman?

  If you believe even ha, even if they have to do basically like a quarter of the stuff they have to do in the movies, it's exhausting.

• 1:41Neil deGrasse Tyson?

  Exactly. You said Star Trek, too?

• 1:42Eugene Mirman?

  Star Trek. Yeah, I love, I love time travel.

• 1:46Neil deGrasse Tyson?

  Because there are ways to do time travel that are like astrophysically legitimate.

• 1:50Eugene Mirman?

  Yes.

• 1:50Neil deGrasse Tyson?

  Yeah, yeah.

• 1:51Eugene Mirman?

  And while... Those are my favorites. Sometimes I'll watch a time travel thing and be like, pretty realistic.

• 1:56Neil deGrasse Tyson?

  Tonight, we're featuring... My interview with Christopher Nolan. Mm-hmm. Christopher Nolan. He came through town. Yeah. And I snared him, put him in my office. Uh-huh. And I milked him for forty minutes of... Well, you're not gonna see all forty minutes here. Did you ever have him take it like a top and spin it? To find out which reality we're in. Yeah, you watched all his movies, right? I have seen a bunch of his movies. It was inception. Right, right. To know whether you're... Were you dreaming or in the fifth world? I don't know. Yeah. So, of course, we talked about how he thinks about time and space. Mm-hmm. And that would have been enough just to talk about inception, but... Uh-huh. His most recent movie is... Interstellar? Interstellar. Yeah. Where it's more not only time and space, it's especially relativity. Now, I know some relativity. Yeah.

• 2:41Neil deGrasse Tyson?

  Okay, but I don't know it... How much in comparison? No, no. You know, I do some relativity. Yeah. I can do that. However, I don't count myself as an expert in relativity. I got... I have to reach out into the ether to find such people. And we did just that with my special guest, Janna Levin. Janet, welcome to StarTalk.

• 3:03Janna Levin?

  Thank you. So glad to be here.

• 3:07Neil deGrasse Tyson?

  Janna Levin is professor of physics and astronomy at Barnard College. And Janet, you're like all grown up because when I first met you, you were an undergraduate at Columbia.

• 3:18Janna Levin?

  I was just telling somebody. I didn't think you remembered that.

• 3:20Neil deGrasse Tyson?

  Oh, yeah. Oh, my. She was like, she was just this little girl. She was so cute.

• 3:24Janna Levin?

  It's true.

• 3:24Neil deGrasse Tyson?

  What you maturing in? Oh, she's maturing in there.

• 3:27Janna Levin?

  I was so little.

• 3:27Neil deGrasse Tyson?

  You're a professor, wrote books, and expert on relativity and cosmology. So you would rank...

• 3:33Janna Levin?

  I looked up to you, Neil.

• 3:34Neil deGrasse Tyson?

  Oh, thank...

• 3:35Janna Levin?

  You were writing your PhD thesis at the time. I remember.

• 3:38Neil deGrasse Tyson?

  Notice that was in past tense. I looked up to you back then. Okay.

• 3:42Janna Levin?

  I still do. I still do.

• 3:43Neil deGrasse Tyson?

  So you're a full-fledged cosmologist, and people like pay you to do this.

• 3:47Janna Levin?

  Yeah, yeah. I get paid to do relativity.

• 3:49Neil deGrasse Tyson?

  To do relativity. You think about black holes and the birth of the universe?

• 3:52Janna Levin?

  Yep.

• 3:52Neil deGrasse Tyson?

  And so you were like the right person to think about and talk about...

• 3:56Janna Levin?

  Well, we'll see how it goes.

• 3:57Neil deGrasse Tyson?

  Yeah. We'll see. Okay. Janet, you have stars on your...

• 4:01Janna Levin?

  I do. You know, I knew you were gonna wear a thematic tie. I just knew you were. So I thought I would match the sort of...

• 4:06Neil deGrasse Tyson?

  This is a black hole. I know no one...

• 4:08Janna Levin?

  Verse.

• 4:11Neil deGrasse Tyson?

  And it is spherical.

• 4:14Neil deGrasse Tyson?

  With the horizon, with a...

• 4:17Neil deGrasse Tyson?

  I didn't know where our conversation would go tonight, but I have every possible cosmic object of this tie, including a wormhole and black holes and galaxies. And this is the best way to wear it if you're eating like lasagna, because if something just falls on it, it's just another nebula, you know, you would never know, know from it. What we want to really talk about is the science of the film Interstellar. You've seen Interstellar.

• 4:39Janna Levin?

  I did.

• 4:40Neil deGrasse Tyson?

  Good, good.

• 4:41Janna Levin?

  Absolutely.

• 4:42Neil deGrasse Tyson?

  And it's a, it's quite an orgy of relativity.

• 4:46Eugene Mirman?

  Yeah, would you say when, when Matthew McConaughey cries, would you be like, is that physically, that's realistic?

• 4:52Janna Levin?

  Is that physically plausible?

• 4:53Eugene Mirman?

  Within the realm of physics, is that?

• 4:54Janna Levin?

  Yeah, that was the part that I was not examining scientifically.

• 4:57Neil deGrasse Tyson?

  So what I did was when I, when I started talking to Christopher Nolan, he's not himself a scientist, he's a movie director and producer, but I always liked knowing if there's some influence, some teacher, somebody who sensitized you to this whole world of science. Let's find out.

• 5:14Speaker 03

  I think a lot of my interest in physics is from when I was about 10, and I was really watching the original Cosmos.

• 5:21Neil deGrasse Tyson?

  Oh.

• 5:22Speaker 03

  That was huge impact on me.

• 5:23Neil deGrasse Tyson?

  Oh, you're so young, oh my gosh!

• 5:24Speaker 03

  I'm so young, exactly. Well, it was post-Star Wars, you know, that late 70s, and the shuttle was about to go up for the first time.

• 5:31Neil deGrasse Tyson?

  So it was in the air?

• 5:32Speaker 03

  It was absolutely everywhere.

• 5:34Neil deGrasse Tyson?

  Yeah, the original Cosmos was 1980 with Carl Sagan.

• 5:36Speaker 03

  And I remember watching that avidly.

• 5:39Neil deGrasse Tyson?

  So you were feeling it?

• 5:40Speaker 03

  Oh, yeah, feeling it in a big way. And I think, I mean, it's a testament to the kinds of things that you're doing and so many people are doing educationally, but I think really, that 10, 11-year-old, you know, you get really fascinated by it. What I found in school was, I reached a point where the mathematics became a burden, and I wasn't as interested in mathematics as I was in, you know, English and writing and that, and that kind of thing. And so, it's where physics starts to depend more on the math. I sort of lost it at that point.

• 6:07Neil deGrasse Tyson?

  That's a fair point. I mean, there's a lot of good physics where you can follow just because it's really cool to think about.

• 6:13Speaker 03

  Exactly.

• 6:14Neil deGrasse Tyson?

  Right, and after that, you're kind of done, right? Go on with the rest of your life. But at least it was in there, percolating.

• 6:18Speaker 03

  Yeah, very much. I remember all those great experiments on Newton's laws, you do with the little, rolling little lead balls down there, and slides and things.

• 6:25Neil deGrasse Tyson?

  Back when they made things out of lead.

• 6:27Speaker 03

  Exactly.

• 6:28Neil deGrasse Tyson?

  Before we knew that it would make us stupid and kill us all.

• 6:34Neil deGrasse Tyson?

  Christopher Nolan, so he had, you know, he studied English literature in college. And so, one of my big things is to get more artists interested in science. So that they can fold the science into their art and take us to new places.

• 6:50Janna Levin?

  Yeah, absolutely.

• 6:50Neil deGrasse Tyson?

  And you, like, wrote a novel.

• 6:53Janna Levin?

  Oh, yeah.

• 6:53Neil deGrasse Tyson?

  That that's, that you're not, you're a professor, a cosmologist, not to be confused with cosmetologist, right, just to be clear. All right, but you wrote a novel, but that's, that's some artistic expression.

• 7:05Janna Levin?

  I mean, I think that this idea that we have to choose at some stage in our lives is kind of silly, you know, we, we go through this process where suddenly we have to decide we're going to be one thing or the other, when actually, most of us are really a combination of those things, right?

• 7:18Eugene Mirman?

  Christopher Nolan is right, it's the equations that really make science so dreary.

• 7:22Janna Levin?

  Oh, no, the math is so beautiful, I do understand.

• 7:25Eugene Mirman?

  Nolan's saying it's not beautiful, it's just as dreary.

• 7:27Janna Levin?

  Oh, no, it's, it's, it's such a way in, and it's such an exciting part of it. I love doing the mathematics, and I think that is exactly the fork in the road. You get to that fork in the road where you're mesmerized by the universe, you discover the math, you either hate it or you love it.

• 7:39Neil deGrasse Tyson?

  You get to the fork in the road and you pick it up.

• 7:41Janna Levin?

  And you pick up the fork?

• 7:42Neil deGrasse Tyson?

  Pick up the fork.

• 7:45Neil deGrasse Tyson?

  Yogi Berra.

• 7:46Janna Levin?

  Sounds very meta.

• 7:47Neil deGrasse Tyson?

  Yeah. So, but, so the mathematics for you, apparently not for Eugene, is...

• 7:54Eugene Mirman?

  Let's just say not for artists.

• 7:56Neil deGrasse Tyson?

  No, no, no, no, but it can be. Right, one doesn't need to be completely mathematically fluent to nonetheless bask in the majesty of the cosmos.

• 8:03Eugene Mirman?

  I mean, I love logarithms, I'm not an idiot.

• 8:08Neil deGrasse Tyson?

  You love logarithms to the base e.

• 8:10Eugene Mirman?

  I love them to base 4, base 7, and 12. Boom, I might be saying a thing that's right.

• 8:19Neil deGrasse Tyson?

  So, but what the equations do, if you want to take that one step deeper, it's like, you part the, you part the curtains, this veil of the beauty of the universe, and there is the machinery operating, there is the language.

• 8:30Eugene Mirman?

  Yeah, no, I get, we wouldn't have, like, stoves and electricity and fridges and stuff and cars, I'm very happy with science.

• 8:36Janna Levin?

  But the math is actually, the math is actually a pleasure to do the math. And at some level, you know, there's this confidence because one thing follows the other. You say following the chalk and then you have this confidence when you're at the end of the line.

• 8:48Neil deGrasse Tyson?

  Following the what?

• 8:48Janna Levin?

  The chalk. You know, you're at the chalkboard and you follow the chalk.

• 8:51Neil deGrasse Tyson?

  What's a chalkboard?

• 8:53Janna Levin?

  I still have one.

• 8:54Neil deGrasse Tyson?

  You still have a chalk, actually I have one too.

• 8:55Janna Levin?

  I saved one from a demolition.

• 8:57Neil deGrasse Tyson?

  Yeah, yeah, they're historical relics. You know, with Christopher Nolan, he opened a new portal to movie making and storytelling. That scientists are people too.

• 9:07Janna Levin?

  Scientists are people too.

• 9:08Neil deGrasse Tyson?

  I think about any sci fi movie from the 50s. Who is the scientist? Is the crazy person behind in the lab coat, wiry hair? You don't care if they're in love, you don't care if they have kids.

• 9:20Eugene Mirman?

  It's only in the 70s when scientists started to have feelings.

• 9:24Neil deGrasse Tyson?

  And almost always the scientist is like co-opted by a bad person. Or the scientists themselves are evil and want to take over the world or destroy the world. And scientists save the day. Not politicians, it's not leaders, it's not, it's just people who, who get the job done and who know their math and physics. And so that, that was, and of course, you know, in, in, in the, in the plot line, they, they visit an exoplanet. And we recently had the announcement of a whole boatload of exoplanets discovered by the Kepler telescope. By the way, that was not an accidental discovery of the telescope. It was conceived, designed and built to discover earth-like planets around sun-like stars.

• 10:07Neil deGrasse Tyson?

  So the fact that this catalog exists with such richness of what could be twins to earth is not itself a surprise. But the fact that so many planets do exist, I'm ready. Give me the list, you know, and the day we can travel through space, we know the order of planets that we might.

• 10:25Eugene Mirman?

  Do we have an order now of planets we'd go to?

• 10:27Neil deGrasse Tyson?

  Well, there are planets, that's a great question. So there are planets that you can say, well, okay, it's about earth-sized, so put a check in that box. Is there an atmosphere? We don't fully know that just yet, but if it does, that would be a good thing. Does, can you breathe the atmosphere? Is the planet the right distance from its host star? So Janet, do you have a way to get to one?

• 10:46Janna Levin?

  No, we really don't have a very good theoretical way. I mean, we, we know that even if you travel at the speed of light, the nearest exoplanets are a certain number of light years away. So even traveling at the speed of light.

• 10:58Eugene Mirman?

  But light years like 10,000 or like seven?

• 11:00Janna Levin?

  Well, I think, no, actually, I think, I think really quite close to us, maybe within a few hundred light years, we should be having the healthy number of exoplanets.

• 11:08Neil deGrasse Tyson?

  Yeah, so if you draw a sort of a couple hundred year radius.

• 11:12Janna Levin?

  Sphere around us.

• 11:13Eugene Mirman?

  So it'd still be like 100 years.

• 11:14Janna Levin?

  Well, only if you're going actually at the speed of light. And by comparison, Voyager, which is, you know, gone the furthest of any human made objects, just breaking out of the Earth's solar influence, it'll be 10,000 years before it comes across another star system. Because we're not going anywhere near the speed of light.

• 11:30Neil deGrasse Tyson?

  Right. In fact, when Voyager did its tour of the major planets, it, we discovered that the moons of those planets were more interesting than the planets themselves. The moon Io and Europa and, and all of these moons, they have volcanoes and some of them have atmospheres and lakes of methane. And so you're right, we're no longer restricted to planets. Excellent. So, so the, the net that we cast in the search for life as we know it has gotten larger.

• 11:58Janna Levin?

  Yeah, they should have just gone to Jupiter's moons. It would have been a shorter trip.

• 12:01Neil deGrasse Tyson?

  Jupiter's moons.

• 12:02Janna Levin?

  All the way.

• 12:03Neil deGrasse Tyson?

  Right, right. Jupiter's got it all. If you gotta live anywhere, holding aside the radiation fields that would cook your gonads, it's otherwise a really good place to start civilization. Jupiter has a very strong magnetic field and it traps dangerous particles and it's.

• 12:19Eugene Mirman?

  That's why the movie, you didn't, we didn't go to Jupiter.

• 12:21Neil deGrasse Tyson?

  Well, actually, I don't know if you remember from your chemistry class. Uh, in, in your chemistry class, remember that mysterious chart of boxes in the front of the room? Yeah, the periodic table of elements. So in there, did you remember that hydrogen appeared on the left and on the right? Did anybody remember that? It's in two places and the left hand side are like, are, are metals and the right hand side are non-metals. Hydrogen, depending on the conditions under which you find it, can behave as, as though it's a metal. As well as a gas. And hydrogen behaves as a metal in the core of the planet Jupiter. Where it's under so much pressure that the configuration of the atoms is such that it can move electrons around

• 13:06Neil deGrasse Tyson?

  just the way a metal does, and it can conduct electricity. And if you can conduct electricity, you can create a dynamo. If you create a dynamo, you can create an awesome magnetic field.

• 13:17Eugene Mirman?

  What's a dynamo?

• 13:19Neil deGrasse Tyson?

  A dynamo, do you want to take this?

• 13:21Janna Levin?

  No, no, please, I'm digging your explanation.

• 13:24Neil deGrasse Tyson?

  So if you can, if you, in a rotating system, you can send up, you can create electrical currents inside wherever you conduct electricity. And wherever you have moving charges, you can create an electric field. And with the electric field, you have an attendant magnetic field. And so you can drive magnetic forces with this. But if they didn't have anything magnetic inside, you wouldn't have a, you wouldn't have poles, you wouldn't have a magnetic field.

• 13:50Janna Levin?

  The Earth has a weak dynamo.

• 13:51Neil deGrasse Tyson?

  One of the bits of strong evidence, we had something metallic in the center, was that we, Earth has a magnetic field, we have an iron core. Yeah, exactly.

• 13:57Janna Levin?

  But it's a weak one, so there are things like...

• 13:59Neil deGrasse Tyson?

  It's weak.

• 14:00Janna Levin?

  There are things like neutron stars, which have magnetic fields a trillion times the magnetic field of the Earth.

• 14:04Neil deGrasse Tyson?

  A trillion times.

• 14:05Janna Levin?

  A trillion or more, or a thousand trillion times the magnetic field of the Earth.

• 14:09Neil deGrasse Tyson?

  Yanking nails out of your shoes and things.

• 14:12Janna Levin?

  Yeah, you don't want to go near them, but they can make you...

• 14:14Eugene Mirman?

  You don't want to go near, what kind of a star again?

• 14:17Janna Levin?

  It's a magnet, it's a, a neutron star is a dead star, a collapse star.

• 14:21Eugene Mirman?

  Because it'd be too magnetic, that would be the main risk?

• 14:23Janna Levin?

  Many, many other reasons.

• 14:24Eugene Mirman?

  And then it would be burning right away.

• 14:26Janna Levin?

  Yeah, and yeah, you'd basically be liquefied on the surface because of gravity.

• 14:30Neil deGrasse Tyson?

  Yeah, yeah, so ignoring the fact that the gravity is so strong, it would liquefy you.

• 14:35Eugene Mirman?

  Right.

• 14:36Neil deGrasse Tyson?

  It's a really bad magnetic field, too.

• 14:39Eugene Mirman?

  And it's hot, it's very hot?

• 14:40Neil deGrasse Tyson?

  Yeah, uh, yeah, it depends on how old it is.

• 14:43Janna Levin?

  They're not hot like stars.

• 14:44Eugene Mirman?

  But they're hotter than a microwave.

• 14:46Janna Levin?

  Well, uh, I, yeah, that's a weird comparison, I suppose it has to be.

• 14:50Neil deGrasse Tyson?

  Wait, wait, wait, you mean, microwave ovens never get hot. It's only the food. Okay, you're right. What kind of oven do you have? The worst examples. Yes, it was. Convection oven?

• 15:02Janna Levin?

  No, but what they do beautifully is they act like a lighthouse because of that big magnetic field, so that you can see these neutron stars at great distances.

• 15:09Neil deGrasse Tyson?

  As they rotate.

• 15:10Janna Levin?

  It's literally a lighthouse, it's like a beacon, and they're these incredible

• 15:13Neil deGrasse Tyson?

  But in space, a lighthouse in space.

• 15:14Janna Levin?

  In space, in our galaxy, we see them.

• 15:16Neil deGrasse Tyson?

  In fact, they're key neutron stars in the galaxy where you can uniquely triangulate on the solar system from where those spinning neutron stars are. We call them pulsars. When StarTalk returns, we'll learn about matter and energy, which relativity says distorts the fabric of space and time. It's a fundamental element in the film Interstellar. Not only in where they go in the universe, but where he goes with his plotlines. When we come back to StarTalk.

• 15:53Neil deGrasse Tyson?

  We're back, StarTalk.

• 15:56Neil deGrasse Tyson?

  Right here in the Rose Center for Earth and Space, the Hall of the Universe. So many names for one giant room.

• 16:04Neil deGrasse Tyson?

  Well, if it's the center of the universe, you need, you gotta reference it somehow. I'm just saying. I've got Eugene Mirman, my co-host, Professor Janna Levin. Welcome to StarTalk. So good to be here. You are a cosmologist. I am. This is your expertise. It is. For today's show, we're talking about relativity, the universe, cosmology, everything that you are an expert in. On a daily basis. I just dabble in relativity. It is what you do. It is. It is. Well, we're featuring my interview with Chris Nolan. And of course, we talked about just his, how he thinks about time and space. And I just wanted to know from him what's going on in his head that leads him to creating

• 16:47Neil deGrasse Tyson?

  such twisted realities. Let's find out.

• 16:52Speaker 03

  I'm interested in, I call it sort of geometry or topology, you know, it's those kind of things. Not the mathematics of it, that's lost on me, but just the idea of, well filmmaking itself, it's this weird combination of two dimensional images representing three dimensions and then you add time and editing and camera blocking and structure, the way all the things work. They just get you thinking about dimensions, really. Really, it's about, I suppose, shapes and patterns and things. And that's where, you know, the architecture of movies and movie craft is interestingly structured. And so as I started to make films, I got more and more interested in kind of addressing that in the narrative itself. And it just pushes you to think.

• 17:34Neil deGrasse Tyson?

  If you put it in a narrative, it means it's a deeper part of the story. Rather than just some flashy razzamatazz.

• 17:40Speaker 03

  Yeah, and you start to think about what it means to you, you know, like why something, why you want to displace a chronology, why you want to tell a story with a beginning, a middle and an end, but not in that order, you know, that kind of thing. And it got me thinking about how we tell stories in real life. We don't get it beginning, middle and end. You know, we read a newspaper, it gives us the headline version, you know, man bites dog. Then it starts to fill in all the details. And then you get another version of the story the next day and you get more details and everything again. And I thought, you know, why make films that just give you the beginning, the middle and end in a linear form when that's not really the way we experience life in a funny sort of way.

• 18:13Neil deGrasse Tyson?

  And it's way more intriguing that way.

• 18:16Speaker 03

  I think so.

• 18:17Neil deGrasse Tyson?

  Now I have to think more deeply, I have to pay closer attention. Yeah, so he's messing with time. Jana, what is time?

• 18:25Janna Levin?

  Simple.

• 18:26Neil deGrasse Tyson?

  One sentence or less.

• 18:28Janna Levin?

  Yeah, it is actually one of the most elusive aspects of physics. There's this idea.

• 18:33Neil deGrasse Tyson?

  Or life.

• 18:34Janna Levin?

  Or of life, right, psychologically. But even physically, we know that there is this sort of clock, the clock never stops, we never turn around and go back, we can never accidentally go the wrong direction in time, it's always pushing us forward. And yet we sort of imagine it almost spatially, we almost imagine it like a dimension. But I can't look forward in that dimension the way I can look left and I can't turn around and look back in that dimension the way I can look right, right? And so that aspect of why time is different from a dimension remains sort of persistently confusing.

• 19:03Neil deGrasse Tyson?

  So then, now we start twisting time. And no one thought to do that until Einstein, I guess. Is that a fair? A fair characterization.

• 19:11Janna Levin?

  I mean, people may have imagined it culturally, but it wasn't actually on the table as a viable possibility until Einstein, and it is a viable possibility. We know that my clock can run differently from your clock, and that there can be a difference between not only our psychological perception of time, but our biological perception of time.

• 19:28Neil deGrasse Tyson?

  But, but, but our clocks are not going to run differently if we're in the same place at the same time.

• 19:32Janna Levin?

  No, they're not.

• 19:33Neil deGrasse Tyson?

  No, no.

• 19:34Eugene Mirman?

  But if you're in two different places.

• 19:35Neil deGrasse Tyson?

  Then you have to ask what's different about those two places.

• 19:37Janna Levin?

  If I'm higher up in a building, if I'm in the space station, if I'm near a black hole, my clock will run differently than yours. The further away I am from the earth, the, um, you know, the faster my clock will appear to run relative to yours.

• 19:51Eugene Mirman?

  So if I go to a black hole and have a sandwich and then come right back, how long will it have seemed?

• 19:55Janna Levin?

  Civilization has come and gone.

• 19:56Eugene Mirman?

  It'll all be gone.

• 19:58Neil deGrasse Tyson?

  So if you fold relativity into a storytelling narrative, now time can be legitimately altered and warped.

• 20:09Janna Levin?

  Sure.

• 20:09Neil deGrasse Tyson?

  For the purposes of, of your plotlines.

• 20:12Eugene Mirman?

  So is Interstellar realistic, but Star Trek IV: The Voyage Home a little unrealistic?

• 20:16Janna Levin?

  Well, I honestly don't remember The Voyage Home, but I can tell you.

• 20:19Neil deGrasse Tyson?

  How could you not remember The Voyage Home?

• 20:20Eugene Mirman?

  It's like, shout it out to the sun!

• 20:22Neil deGrasse Tyson?

  And they saved the whales, right?

• 20:25Eugene Mirman?

  And humanity.

• 20:26Janna Levin?

  It might be the one I never saw. I think I didn't like that they came back to the present. It was like, it wasn't the most exciting one in the canon, you know?

• 20:33Neil deGrasse Tyson?

  Yeah, yeah, they did come back to the present.

• 20:34Janna Levin?

  They came back to the present. I wanted them to be in the future. But the, the thing about going near a black hole, yes, you can absolutely go incredibly close to a black hole. I think I once asked how close they had to be in Interstellar. It was something like a millionth the size of the event horizon of the shadow. Like, you had to be just really on top of it.

• 20:51Neil deGrasse Tyson?

  What you're saying is, in the film,

• 20:53Janna Levin?

  Yeah.

• 20:53Neil deGrasse Tyson?

  they go near a black hole.

• 20:54Janna Levin?

  Yeah.

• 20:55Neil deGrasse Tyson?

  Close enough to a black hole that the strength of gravity is so high.

• 20:58Janna Levin?

  Yes.

• 20:59Neil deGrasse Tyson?

  That time goes so slowly.

• 21:02Janna Levin?

  Yes.

• 21:02Neil deGrasse Tyson?

  That, what is it, one hour at this black hole planet?

• 21:06Janna Levin?

  I thought it was like 23 years, something like that, yeah.

• 21:08Eugene Mirman?

  It would be, that is the act of math of it.

• 21:10Janna Levin?

  Yeah, you can calculate how close you'd have to get for that to happen. Now, the thing is, is that their experience of time is completely normal.

• 21:17Neil deGrasse Tyson?

  Any time difference you want to write a story around, you can calculate how, what's the strength of gravity that will give you that time difference. Yeah, so there you go.

• 21:27Janna Levin?

  Right, so their experience of time is completely normal. They have this very rushed hours to try to get back out away from the black hole. And many years have passed relative to the Earth.

• 21:37Neil deGrasse Tyson?

  In fact, in the film, Anne Hathaway's character said the most perceptive thing about it. That when there's this difference in your rate of your clock ticking, time itself becomes a commodity.

• 21:50Janna Levin?

  Uh huh, yeah. Yeah, exactly, and it's like a natural resource.

• 21:54Neil deGrasse Tyson?

  A natural resource. You go down to the black hole, your time is ticking so slowly, you're at risk of when you come back, that your kids are now dying in their deathbed.

• 22:03Janna Levin?

  The things you care about that are motivating you to go near the black hole in the first place, because I don't know why you would really want to do that.

• 22:11Janna Levin?

  Right, all of that is gone. And that is actually a really powerful moment in the film. But what might not be as realistic is the question of whether or not they would have enough fuel to execute these things. This becomes very expensive to escape from a black hole.

• 22:25Eugene Mirman?

  Is that realistic?

• 22:27Janna Levin?

  Ask Neil.

• 22:29Eugene Mirman?

  Neil, can you live behind a bookcase if you're an astronaut? Never mind.

• 22:35Neil deGrasse Tyson?

  So, but it's one thing to have time tick at different rates. It's another thing to be able to visit your past. Or to see your timeline writ large in front of you. That's taken yet an extra step here.

• 22:48Janna Levin?

  It is an extra step. A lot of people think that somehow the physical laws will protect us from that, that there will be some barrier to being able to do that.

• 22:57Neil deGrasse Tyson?

  In other words, you're saying some people think there's a yet to be discovered physical law that will declare...

• 23:04Janna Levin?

  Right.

• 23:04Neil deGrasse Tyson?

  In our revelation of this law.

• 23:06Janna Levin?

  Yeah.

• 23:07Neil deGrasse Tyson?

  That thou shalt not go back in time and prevent your parents from meeting. If your parents don't meet, then you're not born. Then you can't have gone back in time to have prevented them from meeting.

• 23:16Janna Levin?

  So it's actually technically possible in the context of relativity to do this. Like, there are mathematical proofs that if Einstein's theory of relativity is the whole story, then there are certain situations in which you can absolutely go back in time. And this is really problematic, but you're presuming that you have the will to go and stop your parents from meeting. And maybe you can't do things like have will and volition that's inconsistent with the laws of physics.

• 23:41Neil deGrasse Tyson?

  Or it may be.

• 23:41Janna Levin?

  Maybe you can't do that.

• 23:42Neil deGrasse Tyson?

  It may be that you don't purposely stop them from meeting. You do something else that changes all the history of the future of the world. You're literally describing Back to the Future. But I understand, we can pretend you're not. But given that, you can get very interesting plotlines such as what was in The Terminator, Terminator 1, 2, and 3, and all of these, these time travel movies. Well, coming up, we'll learn about one of the most twisted plotlines imaginable. Traveling through a wormhole on StarTalk.

• 24:26Neil deGrasse Tyson?

  We're back. StarTalk. In the heart of New York City, the American Museum of Natural History, I'm your host, Neil deGrasse Tyson, of course. Jana, Professor Jana.

• 24:37Janna Levin?

  I'm so glad to be here.

• 24:38Neil deGrasse Tyson?

  Yeah, thanks. We're talking about Interstellar. Yeah. The film. And one of the most important plot elements, scientific elements, storytelling elements, is the existence of and their journey through a wormhole. And in fact, we've got an image of a wormhole. Let's check it out. Oh, yeah.

• 25:02Neil deGrasse Tyson?

  The wormhole is a portal through space and time. Where, in this particular case, we're actually seeing what's on the other side of the wormhole come through us, through the hole, through the channel optically. And that hole leads to another place. So, we both know, one of the advisors, one of the science advisors, the lead science advisor of the film Interstellar, Kip Thorne.

• 25:25Janna Levin?

  Kip Thorne, the wonderful, amazing, fascinating Kip Thorne.

• 25:28Neil deGrasse Tyson?

  Yeah, he's brilliant.

• 25:29Janna Levin?

  He'll take your word for it. I like this Kip person already.

• 25:34Neil deGrasse Tyson?

  No, you should have said, "Wait, I found an error in one of his papers." That was your cue for that.

• 25:39Janna Levin?

  I'll find it, I'll look through his footnotes, that's where they hide the money.

• 25:42Neil deGrasse Tyson?

  So, Kip Thorne, he's an expert on relativity. I have a book in my office, co-authored by him. The title of the book is "Gravitation," and it's like a zillion pages thick. And I, we always joked, it's the only subject you ever learned about just by carrying the textbook around. So let's find out what Christopher Nolan had to say about working with Kip Thorne on Interstellar.

• 26:07Speaker 03

  Like, Kip, we were talking about the wormhole, because it was always in the script.

• 26:12Neil deGrasse Tyson?

  Because he's a wormhole guy.

• 26:13Speaker 03

  He's a wormhole guy, and I was sitting there talking to him about it.

• 26:15Neil deGrasse Tyson?

  He put the wormhole in contact, okay?

• 26:17Speaker 03

  Yeah, yeah, and, you know, he is Mr. Wormhole.

• 26:20Neil deGrasse Tyson?

  Yeah, yeah.

• 26:20Speaker 03

  Kip Wormhole Thorne.

• 26:21Neil deGrasse Tyson?

  Yes, on his business card.

• 26:22Speaker 03

  Exactly.

• 26:23Neil deGrasse Tyson?

  Wormhole, talk to me.

• 26:24Speaker 03

  I said to him, we were talking about the hole, and much like McConaughey's character, because I put this into the dialogue of the film, at one point I said, "Well, wait a second, you're saying it's not a hole, it's a sphere." And he's like, "Of course it's a sphere, you know, it's a hole in three dimensions." I'm like, "No, there's no of course about that for the rest of us."

• 26:42Neil deGrasse Tyson?

  Oh, hence you explicated it.

• 26:43Speaker 03

  Hence, no, because I was like, if we can make somebody understand, somebody who understands the way I suddenly did in that moment of, "You can have a hole in three dimensions?"

• 26:51Neil deGrasse Tyson?

  Yes.

• 26:52Speaker 03

  That's a terrifying concept, and really cool.

• 26:54Neil deGrasse Tyson?

  The fact that you can approach it from any direction and disappear inside of it.

• 26:56Speaker 03

  Yeah, really cool.

• 26:58Neil deGrasse Tyson?

  Because a hole in the pavement, you know, a manhole cover, that's a hole you fall through.

• 27:02Speaker 03

  Yeah.

• 27:03Neil deGrasse Tyson?

  But that's a hole in a surface, which is a circle.

• 27:05Speaker 03

  Well...

• 27:06Neil deGrasse Tyson?

  A hole in three dimensions is a sphere. And so that was brilliantly done, and gave you a feeling that it's a hole that you can enter from any direction.

• 27:14Speaker 03

  A lot of what I dealt with, with Kip, and, you know, when you get into the fine detail, where you really try and dig down into this, there's a point where, you know, Kip will sort of go... Well, that's kind of how we let you guys think of it. You know, and he's the last guy, he's never exclusionary about his science or whatever, but there's just a point where he's sort of like, "Look, you know, you have to trust me on this." It's like, we give you a sort of simple model of it and try and, you know, make it accessible in that way, and then if you dig too deep in that, you have to go to the next level. The next level is exponentially more complicated.

• 27:47Neil deGrasse Tyson?

  Right, right, yeah, you don't want to have to go there.

• 27:49Speaker 03

  No, you don't want to have to go there.

• 27:50Neil deGrasse Tyson?

  Right.

• 27:51Speaker 03

  Because algebra will be involved.

• 27:52Neil deGrasse Tyson?

  So, Jan, a madam cosmologist.

• 27:56Janna Levin?

  Yes. I love what they did here was to make the portal three-dimensional. But because we're in a three-dimensional space-time, you need a three-dimensional portal to move from all these three dimensions to a different location. We like to imagine, from three dimensions, things that are lesser dimensions. It's a lot easier to visualize.

• 28:13Eugene Mirman?

  We all love imagining six dimensions.

• 28:15Janna Levin?

  It's really hard.

• 28:16Eugene Mirman?

  Let's give it a try, let's all try it right now.

• 28:18Neil deGrasse Tyson?

  Okay, everybody try it right now.

• 28:19Janna Levin?

  This is gonna take a while.

• 28:22Eugene Mirman?

  Not bad.

• 28:23Janna Levin?

  I think, I'm not sure if I'm remembering this correctly, but I think in the movie, they make reference to actually higher-dimensional spaces. That in the movie, it's not just a whole three-dimensional universe, that there is something that they're calling a bulk, which is a higher-dimensional universe in which these three dimensions are embedded.

• 28:37Neil deGrasse Tyson?

  So, the notion that you can fall into something from any direction, that alone boggles the mind. It's a three-dimensional hole. And that hole leads to another place.

• 28:51Janna Levin?

  Yeah, it can be a lot bigger on the inside than it is on the outside.

• 28:54Neil deGrasse Tyson?

  We've heard that before. She's showing her Doctor Who street cred. The TARDIS is bigger on the inside than on the outside.

• 29:03Eugene Mirman?

  Is the TARDIS realistic when you describe it as realistic?

• 29:05Janna Levin?

  Very realistic.

• 29:06Eugene Mirman?

  Excellent.

• 29:07Neil deGrasse Tyson?

  Well, for being a fourth-dimensional fictional story, it's really realistic.

• 29:10Eugene Mirman?

  Yeah. Once you add that context, everything becomes quite reasonable.

• 29:16Neil deGrasse Tyson?

  So what are wormholes good for? You have one?

• 29:18Janna Levin?

  Yeah, you know, wormholes, although they're probably theoretically possible, are physically, as far as we know, still impossible. Meaning to keep the throat open of the wormhole, you need forms of matter and energy that we've never seen before. We don't know anything that could actually keep the throat open of the wormhole. So it'll kind of keep closing up.

• 29:36Neil deGrasse Tyson?

  So it's unstable?

• 29:38Janna Levin?

  It's very unstable.

• 29:39Eugene Mirman?

  Meaning if we made a wormhole, we couldn't keep it open, but we also can't make wormholes?

• 29:43Janna Levin?

  Yeah, so if a wormhole if a wormhole was formed by some unstable process, it would quickly close.

• 29:51Eugene Mirman?

  When you say it would close quickly, how long? Like, meaning how long would it take? Seconds or?

• 29:55Janna Levin?

  Like microseconds.

• 29:56Eugene Mirman?

  Microsecond.

• 29:57Janna Levin?

  So I think the question isn't can we make them? But the question is, is there any form of energy in the universe that's capable of keeping a wormhole sort of afloat? And we don't know the answer to that question. We didn't predict dark energy. There are forms of energy that are surprising to us.

• 30:13Neil deGrasse Tyson?

  So we have to be of a civilization that has power over spacetime and energy and matter? That we are not quite yet. And perhaps in that future civilization, we can manipulate the fabric of space and time and make wormholes.

• 30:27Eugene Mirman?

  So what came first? The thing you've said first or wormhole?

• 30:30Janna Levin?

  The sci-fi. I think we'd be better off manipulating space and time by, for instance, doing something like warp drive. So you could do something like warp drive by contracting spacetime between two points, bringing them closer together, jumping across. You don't have to travel, you know, 400 light years.

• 30:44Neil deGrasse Tyson?

  That's not a wormhole?

• 30:45Janna Levin?

  That's not a wormhole. And then pushing it back out again. And then you push it back out again. No big deal. It's not a big deal.

• 30:51Neil deGrasse Tyson?

  No, I want to fight about this.

• 30:54Neil deGrasse Tyson?

  No, no, you're going to warp space and then go from one part of space to the other.

• 30:57Janna Levin?

  And then you jump across and then you push it back out.

• 30:58Neil deGrasse Tyson?

  How are you jumping across? How are you?

• 31:00Eugene Mirman?

  It was a space pogo.

• 31:04Janna Levin?

  Well, you could just step right across if you can pull them closer together.

• 31:07Neil deGrasse Tyson?

  Okay, you have to step out of your dimension and back in.

• 31:09Janna Levin?

  Well, you could do all of this even in three dimensions, just pull two spacetime points closer. Now, again, it has the same problem, which is that I don't know forms of matter or energy that would do it. But that's warp drive in principle.

• 31:19Neil deGrasse Tyson?

  We got to talk.

• 31:22Janna Levin?

  Then you just push it back out again where it was before.

• 31:24Eugene Mirman?

  So you would just need to, it would just be like a mirror? You'd just walk through something like a mirror? Or I'm just making names?

• 31:29Janna Levin?

  You're totally making that up.

• 31:31Eugene Mirman?

  I'm not making that up. I just mean, you'd walk through what just seems like a black hole.

• 31:34Neil deGrasse Tyson?

  When StarTalk comes back.

• 31:35Eugene Mirman?

  I want to go through a wormhole!

• 31:37Neil deGrasse Tyson?

  We'll find out more about how Einstein's relativity can stretch the imagination.

• 31:47Neil deGrasse Tyson?

  So we're back. Dark talk. All the universe. Jana, before the break, you said you can warp space and hop from one part of it to another with a pogo stick.

• 31:57Eugene Mirman?

  Or on a bicycle.

• 31:59Janna Levin?

  Yeah, the pogo stick.

• 32:00Neil deGrasse Tyson?

  I don't know how you do that without a wormhole.

• 32:02Janna Levin?

  Well, there is a sense in which we can get space to expand in particular ways.

• 32:07Neil deGrasse Tyson?

  Or contract.

• 32:08Janna Levin?

  Or contract.

• 32:09Neil deGrasse Tyson?

  Yes.

• 32:10Janna Levin?

  And so if you imagine that there's something called dark energy, which you know very well, which causes the universe to expand at a very accelerated rate.

• 32:14Neil deGrasse Tyson?

  Yes.

• 32:14Janna Levin?

  That's one way to push it back out again. If you could come up with a form of energy that did the opposite, that pulled it together, much like dark energy does, right?

• 32:23Neil deGrasse Tyson?

  Oh, okay.

• 32:24Janna Levin?

  But in the opposite direction, causing the collapse of space in one direction.

• 32:26Eugene Mirman?

  Neil, what you're saying is true. Trust me on the science, Neil.

• 32:31Janna Levin?

  So the reason why this is imperative is that you can travel across a very short distance going less than the speed of light, and that's very important, and then the spacetime is able to expand faster than the speed of light.

• 32:40Neil deGrasse Tyson?

  Now I understand. So you're saying, if you can physically stretch, and you had power to do so.

• 32:47Janna Levin?

  To just manipulate a coordinate.

• 32:49Neil deGrasse Tyson?

  Contract, I'd bring California to across the street.

• 32:53Janna Levin?

  You'd walk across the street.

• 32:54Neil deGrasse Tyson?

  I'd walk across the street.

• 32:55Janna Levin?

  And then you'd push it back away again.

• 32:56Neil deGrasse Tyson?

  California back to where it was, and I'm there to...

• 32:57Eugene Mirman?

  And that wouldn't blow everything up, I guess?

• 33:00Janna Levin?

  I'm sure it would have all kinds of unforeseen consequences.

• 33:04Eugene Mirman?

  But you would be in what used to be California.

• 33:07Neil deGrasse Tyson?

  No, but if it's the fabric of space and time, you're not actually squeezing matter to do that.

• 33:13Janna Levin?

  You don't have to squeeze matter. The trick is that there is no...

• 33:15Neil deGrasse Tyson?

  It was a trick.

• 33:16Janna Levin?

  There's no information traveling faster than the speed of light, even though the spacetime is expanding faster than the speed of light. So it's all consistent with the limits of relativity.

• 33:24Neil deGrasse Tyson?

  Okay, when you got this, call me up. We'll figure that one out. So there's relative space, but there's also relativity of time, of course. Let's zoom in on my conversation with Christopher Nolan about the relativity of time.

• 33:38Speaker 03

  You look at relativity itself, insofar as I can understand it, you know, insofar as I'm trying, you know, explaining to the audience what they need to know.

• 33:46Neil deGrasse Tyson?

  It's all mind-blowing.

• 33:46Speaker 03

  It's mind-blowing, the idea that time can run differently for you depending on how fast you're moving or where you are in the universe, that's incredible.

• 33:54Neil deGrasse Tyson?

  Yeah, and I think you took it to an extreme point, which no one had done before. I don't think I'm giving too much of the film away when I say where you visit a planet that's in a very deep gravitational well, we say, and the closer you are to a strong source of gravity, the slower your time ticks relative to people you left at home. And so if you're going to commit to a visit of a planet where time is ticking more slowly, then you've got to be prepared for the consequences of that. How much more slowly is it ticking? And what are the age of your kids relative to you when you go back and find?

• 34:29Speaker 03

  Well, before I go down there, Brad, Anne Hathaway's character has a line, you know, she says, "We've got to view time as a resource, like oxygen."

• 34:38Neil deGrasse Tyson?

  As a commodity.

• 34:38Speaker 03

  Food. Exactly, and I just, I thought it was just a cool idea.

• 34:42Neil deGrasse Tyson?

  That was a great line. So here we have a time moving at different rates for different people, and Jenna, could you just give the lowdown on when your time moves more slowly?

• 34:55Janna Levin?

  So the simplest circumstance that Einstein first thought of was when you're in relative motion. So you're two astronauts flying past each other in totally empty space, and you're in relative motion. One astronaut says, "I'm not moving, you're the one that's moving," and you're moving near the speed of light. They will see that person's clock run very slowly. That person will appear to move slow and talk slow.

• 35:14Neil deGrasse Tyson?

  Everything's slow.

• 35:15Janna Levin?

  But that astronaut will accuse the other of the same thing.

• 35:17Neil deGrasse Tyson?

  Right, so there's the relativity of the passage of time.

• 35:20Janna Levin?

  That's right. Their experience with their own time is normal.

• 35:23Neil deGrasse Tyson?

  And then there's also gravity that does this as well.

• 35:25Janna Levin?

  So gravity does this as well, and you can think of it as a rotation in spacetime. You know, you can rotate left into right, and it turns out you can rotate space into time and time into space. And one way to do that is to have relative motion, and one way to do that is to go near a very heavy object like a black hole.

• 35:41Eugene Mirman?

  So being a black hole, like if you were near Jupiter, it wouldn't be...

• 35:45Janna Levin?

  Technically, you're probably slowing time for me a little.

• 35:47Eugene Mirman?

  Alright.

• 35:48Janna Levin?

  So, it's anything.

• 35:49Neil deGrasse Tyson?

  What he just said is that you have enough gravity.

• 35:51Eugene Mirman?

  Yeah, yeah. That's, that's all I want. Is to walk around New York City slowing down everyone's time by just walking right behind them. Like a normal person.

• 36:00Neil deGrasse Tyson?

  So whether or not you can measure it, you can calculate what effect Eugene's gravitational field is having on the passage of time on your clocks.

• 36:07Janna Levin?

  Yes, and we do notice this with clocks near the Earth versus clocks in the space station.

• 36:10Eugene Mirman?

  What's the biggest thing that's near the Earth that would have this effect in a way that you'd really notice? Like, is it Jupiter, or would it have to be the Sun? Or is there...

• 36:18Janna Levin?

  That's an interesting question. I mean, I've never thought about whether they could do it for the Moon. I mean, maybe. It depends on how precise your clock is, really. That's really the question.

• 36:26Neil deGrasse Tyson?

  You know what they do it for? GPS satellites are farther away from Earth than you are.

• 36:31Eugene Mirman?

  Agreed.

• 36:32Neil deGrasse Tyson?

  And, agree, okay. And so, they, in fact, experience a faster passage of time than we do. But they're sending time signals to your smartphones. And that time signal they send you is correct. How do you get the correct time if they have the wrong time? Because we knew in advance what the effects of relativity would be on the GPS satellite system. And we pre-correct the time that they send down to us, so that when it gets to here on Earth, you have the correct time. And that is general relativity manifest in our, in, in, in our civilization today.

• 37:11Neil deGrasse Tyson?

  When we come back, everything you ever wanted to know about black holes on StarTalk. We're back at StarTalk at the Rose Center for Earth and Space. We do the universe here, in case you didn't know. We're talking today about relativity, about black holes, wormholes. We have a cosmologist, Janna Levin. Uh, Jenna, we, I want to learn more about black holes. Everybody loves some black holes.

• 37:44Janna Levin?

  Oh, yeah.

• 37:44Neil deGrasse Tyson?

  And, we, we have an image. We have an image, an artist's representation of a black hole. Let's check it out, right here. So, I particularly like this because it has sort of what we say in astrophysics is an accretion disk, there's a disk of material that might be feeding the appetite of the black hole as it descends. Also, the black hole is a three-dimensional hole, just the way a wormhole is three-dimensional, and there's clearly sort of a radiation field just on the outskirts of the event horizon. And tell everybody what an event horizon is. I love that term, it's so poetic.

• 38:19Janna Levin?

  It is, it's so beautiful. So, the black hole...

• 38:21Neil deGrasse Tyson?

  It's beautiful to say.

• 38:23Janna Levin?

  It is.

• 38:23Neil deGrasse Tyson?

  Not beautiful to go through.

• 38:24Janna Levin?

  It would be unpleasant. So, the black hole creates a region around it that, where the gravitational field is so strong that essentially not even light can escape. You know, we know we have to launch a rocket off the surface of the earth at a certain speed to get it to escape the earth, and the speed at which you would have to travel to escape from the event horizon is the speed of light. I mean, we will never know anything about what's inside a black hole. That's what the event horizon says. It says, "No information can ever come out." So, we gather from the mathematics suggests that there's something called a singularity at the center, a place where spacetime curvature is so strong that you would just be crushed to death just by gravitational forces. And then, I don't

• 39:08Janna Levin?

  know, blotted out of existence, we don't really know what happens there. A lot of people think that's not the whole story.

• 39:12Eugene Mirman?

  What if you put a black hole in a black hole?

• 39:14Janna Levin?

  Yeah.

• 39:15Eugene Mirman?

  What would happen?

• 39:16Neil deGrasse Tyson?

  There are two that are in a death spiral right now, discovered in the center of a galaxy.

• 39:20Janna Levin?

  They just make a bigger black hole.

• 39:21Eugene Mirman?

  Really?

• 39:22Janna Levin?

  You can't think of a black hole as a thing, it's really...

• 39:23Eugene Mirman?

  It's like a dude?

• 39:24Janna Levin?

  It's like a place.

• 39:25Eugene Mirman?

  A place. It's like Miami. That's a fair...

• 39:29Neil deGrasse Tyson?

  Yeah, so one black hole can eat the other, right? Just a black hole twice as big.

• 39:32Eugene Mirman?

  And then it just becomes a bigger black hole.

• 39:34Neil deGrasse Tyson?

  A bigger black hole. So, in order to tell this extraordinary story about this planet near, orbiting very close to a black hole, they had to sort of loosen up some science shackles in the storytelling. And let's return to my office where I talked with Christopher Nolan.

• 39:50Neil deGrasse Tyson?

  One of my favorite lines from Mark Twain is, "First get your facts straight, then distort them at your leisure."

• 39:58Speaker 03

  Not exactly. I was exactly the process. It's like, "Let's figure out what the reality is," and then I would explain to Kip, "Okay, but for the narrative, I've got to jump over this bit, or ignore this bit, or whatever," and we would have a back and forth about what was allowable and what wasn't. But generally, I found working with Kip, he wasn't sitting there sort of going, "Well, here are the rules of the thing." He was sitting there going, "Well, these are the possibilities. This is what real-world physicists are offering."

• 40:24Neil deGrasse Tyson?

  Which any good science advice should be to an artist, right? Just here's a context, see what you can do with it.

• 40:30Speaker 03

  And what the real world comes up with is so much more mind-blowing.

• 40:35Janna Levin?

  When black holes were first discovered mathematically, nobody thought they were real. Nobody thought there'd be any way nature could make such a thing, right?

• 40:42Eugene Mirman?

  Why hasn't everything been destroyed by a black hole?

• 40:46Neil deGrasse Tyson?

  Eaten by a black hole.

• 40:47Eugene Mirman?

  Yeah, why doesn't everything...

• 40:48Neil deGrasse Tyson?

  Yeah.

• 40:49Janna Levin?

  Yeah, that's a...

• 40:49Eugene Mirman?

  Or are we in one now?

• 40:50Neil deGrasse Tyson?

  Yeah.

• 40:51Janna Levin?

  That is a false reputation. So if you were to replace the sun with a black hole, right now...

• 40:55Eugene Mirman?

  We would be fine.

• 40:57Janna Levin?

  We would be fine.

• 40:58Neil deGrasse Tyson?

  The ER agent for black hole, that's not their actual reputation here.

• 41:02Janna Levin?

  They never did that.

• 41:03Eugene Mirman?

  If you replaced the sun with a black hole, we would be, I mean, aside from having no sunlight...

• 41:07Janna Levin?

  It would be cold and dark.

• 41:08Eugene Mirman?

  Yeah, yeah. But we wouldn't be sucked in and destroyed.

• 41:10Janna Levin?

  We would not be sucked in any...

• 41:12Eugene Mirman?

  Oh, that is such a relief.

• 41:13Janna Levin?

  We would be on exactly the same... We are falling into the sun. The sun is sucking us up, just incredibly slowly.

• 41:18Eugene Mirman?

  Oh, well, tell it, thank you.

• 41:20Janna Levin?

  Like, the sun will blow up long before that happens.

• 41:22Eugene Mirman?

  Oh, okay.

• 41:23Janna Levin?

  We'll collide with Andromeda long before that happens.

• 41:25Eugene Mirman?

  Oh, that's nice. So this is a lot of good stuff.

• 41:27Neil deGrasse Tyson?

  We'll actually kill ourselves long before that happens. Put your priorities in order.

• 41:32Eugene Mirman?

  Our civilization, but maybe, you know, cats might survive.

• 41:37Neil deGrasse Tyson?

  My favorite thing about black holes is what it does to your body when you fall in. As you get drawn into a black hole, feet-first, it begins to stretch you apart, because your feet... Are drawn to the black hole faster than the top of your head is. And then you get taller and taller until you snap into two pieces. When the forces of gravity become greater than the molecular forces that hold your flesh together. And then those two pieces themselves experience this. It's called the tidal force of gravity and they snap and they become one, two, four, eight, 16. Then your stream of particles descending down to the abyss. And meanwhile, you're the, the fabric of space and time funnels gets narrow. So that you are not only stretched head to toe, you are extruded through the fabric of space and time.

• 42:22Neil deGrasse Tyson?

  Like toothpaste through a tube. So, you know, I actually composed a poem about falling into a black hole. May I share it with you?

• 42:31Speaker 04

  Yeah.

• 42:32Neil deGrasse Tyson?

  I shouldn't call it, it's not, it's a rhyme. Poets compose poems. Regular people rhyme stuff, okay? So, so here it is, here it is. In a feet first dive to this cosmic abyss. You will not survive because you will not miss. The tidal forces of gravity will create quite a calamity when you're stretched head to toe. Are you sure you want to go? Your body's atoms, you'll see them will enter one by one. The singularity will eat them and you won't be having fun.

• 43:17Neil deGrasse Tyson?

  So that is one way to die by falling into a black hole. When StarTalk returns, we'll find out why Bill Nye, the Science Guy is pretty sure that saving the world interstellar style is not in our future. On StarTalk.

• 43:44Speaker 04

  This is StarTalk.

• 43:52Neil deGrasse Tyson?

  StarTalk is back. We're talking about the movie Interstellar, featuring my interview with Christopher Nolan in my office at the Hayden Planetarium. And in that film, there's a blight on Earth. We're all gonna die. We need to find another planet. We find another planet, travel through a wormhole to get there. My good friend Bill Nye assesses this scenario in his Bill Nye rant.

• 44:22Speaker 05

  Space exploration brings out the best in us. You don't believe me? How often have you heard somebody say, "If they can put a man on the moon, why can't they blank?" And that blank can be filled up with anything, like cellphone calls that don't get dropped, or better instant mashed potatoes. It all comes from the technology of space. So a movie that's about space has got a lot of potential. But this idea that you can just ruin the place you live and go live somewhere else is unique to our time. I don't think you're gonna really be able to do that when it comes to the Earth. This is where we make our stand. The Earth's only this big, we're all stuck here. What about Mars? No, it hasn't rained on Mars in 3 billion years. And as soon as that spacecraft door opens, you'll notice you can't breathe. See you down the track.

• 45:09Neil deGrasse Tyson?

  Bill Nye, a man on the move.

• 45:15Neil deGrasse Tyson?

  Yeah, he brings up a very important point. No matter how bad Earth was, is there another place that's better? Even after we mess it up as badly as we did? And in Interstellar, they go to a planet that didn't look like the next planet I wanted to go to after Earth. And I also think the people want to terraform planets. After we mess up Earth, let's terraform Mars. What's terraforming? You turn it into Earth-like.

• 45:42Eugene Mirman?

  Why don't we just terraform Earth?

• 45:43Neil deGrasse Tyson?

  Exactly, exactly. If you have the power to turn another planet into an Earth, you have the power to turn Earth back into Earth.

• 45:53Eugene Mirman?

  Yeah.

• 45:54Neil deGrasse Tyson?

  That's how I see it.

• 45:56Eugene Mirman?

  I agree.

• 45:56Neil deGrasse Tyson?

  It's gotta be easier than terraforming a planet and shipping a billion people there. But in any case, the movie Interstellar, as well as some other films of recent years, Gravity among them, it got people talking about the universe, about space travel again, about science, about the value of science literacy in leading characters that maybe you want to be when you grow up. So I chatted with Chris Nolan in my office. I asked him, what effect does he think his movie has on the dreams of a nation and the world?

• 46:34Speaker 03

  I would love for kids today, you know, to, you know, see Interstellar and get inspired about some of them. I mean, it's what you guys have been doing with Cosmos and whatever. I mean, it's like, if you can show people visually, that's why you needed such a lavish visual treatment. It's like, it's about how exciting it is. It's not about numbers on the page, it's about flight of imaginations, about Einstein sitting there imagining sets of twins, one on a train going the speed of light, you know, one at the station. All that stuff. It's so visual and enormous. So anything you can do, you know, either on television or in a movie or whatever, to try and get that scale and excitement across.

• 47:12Neil deGrasse Tyson?

  Another thing, I, in fact, I've I've been telling this to, because people come to me now to comment on newly released science fiction films. I think it's because I had some tweets for the movie Gravity.

• 47:24Speaker 03

  I heard, yeah.

• 47:25Neil deGrasse Tyson?

  Went a little viral, which was not my intent. I was just putting it out there and I I bump into them on the morning news and on the evening news and on, and everyone's had astrophysicist Neil Tyson says, and it's like, my gosh, but that meant that there was an appetite.

• 47:39Speaker 03

  Yeah.

• 47:39Neil deGrasse Tyson?

  But why would anyone care unless the science in a film is now part of the dialogue? Oh my gosh.

• 47:50Neil deGrasse Tyson?

  Science in the Dialogue.

• 47:51Eugene Mirman?

  Yeah. In your defense, gravity got the gravity wrong.

• 47:57Neil deGrasse Tyson?

  Listen, Jana, Professor Levin, thanks for coming. Anytime. And Eugene, it's always great having you on StarTalk. Thank you. You've been watching StarTalk from the Hall of the University, the American Museum of Natural History in New York City. I'm Neil deGrasse Tyson, your personal astrophysicist. And as always, I bid you to keep looking up!