Cosmic Queries – Out There

Neil deGrasse Tyson, co-host Harrison Greenbaum, and astrophysicist Janna Levin answer questions on the far away and the far out, including Andromeda's impending collision with the Milky Way, white holes, a holographic universe, and more. Prepare to get trippy!

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

• 0:00Neil deGrasse Tyson?

  Hello, StarTalkians. Every now and then, we reach into our archives to select some of our favorite shows of the past. Right now, I offer you my conversation with Janna Levin. She's a cosmologist, as well as a friend and colleague. And she will update us on all the latest thinking regarding black holes, as well as whether the entire universe is a hologram. Check it out.

• 0:34Neil deGrasse Tyson?

  This is StarTalk. I'm your host, Neil deGrasse Tyson, your personal astrophysicist. And today's episode is Cosmic Queries, the out-there edition. We're talking about not just astrophysics, but the extremes of astrophysics in space, time, and dimensions. While I have some expertise in that topic, I don't have all the expertise necessary to pull this off. So we called in my friend and colleague, Janna Levin. Jana!

• 1:04Janna Levin?

  Neil, hey!

• 1:05Neil deGrasse Tyson?

  Okay, thank you for coming.

• 1:07Janna Levin?

  I love being here.

• 1:08Neil deGrasse Tyson?

  Not your first rodeo?

• 1:09Janna Levin?

  Yeah, not my first rodeo, but I haven't been in your office in a long time.

• 1:12Neil deGrasse Tyson?

  Okay, well, it's gotten messier, just so you know.

• 1:16Janna Levin?

  In kind of a good way, almost like, I don't know, curatorial way.

• 1:20Neil deGrasse Tyson?

  Curatorial way. And helping me bring some levity to this topic is the one and only Harrison Greenbaum. Harrison?

• 1:26Harrison Greenbaum?

  How you doing?

• 1:27Neil deGrasse Tyson?

  Welcome!

• 1:28Harrison Greenbaum?

  I do think we need to get Marie Kondo up in here.

• 1:30Neil deGrasse Tyson?

  Oh, really?

• 1:31Harrison Greenbaum?

  You have to see which things spark joy.

• 1:33Neil deGrasse Tyson?

  It all sparks joy.

• 1:35Harrison Greenbaum?

  There's a conflagration of joy.

• 1:37Neil deGrasse Tyson?

  Get the hell out of my office.

• 1:38Janna Levin?

  Exactly. We'll barricade it, we'll barricade it.

• 1:43Neil deGrasse Tyson?

  So you're a comedian and a magician?

• 1:46Harrison Greenbaum?

  Yes, absolutely.

• 1:47Neil deGrasse Tyson?

  That's crazy.

• 1:48Harrison Greenbaum?

  Oh, yeah.

• 1:48Neil deGrasse Tyson?

  Dude, stay here, I don't want you to disappear.

• 1:49Harrison Greenbaum?

  Classic double threat.

• 1:51Neil deGrasse Tyson?

  Don't make my guest disappear today, right?

• 1:53Harrison Greenbaum?

  Absolutely. I use my powers for good, I'm a good witch.

• 1:57Neil deGrasse Tyson?

  And so we'll find you at harrisongreenbaum.com.

• 2:00Harrison Greenbaum?

  Yeah.

• 2:00Neil deGrasse Tyson?

  With your tour schedule and everything.

• 2:01Harrison Greenbaum?

  And also, maybe Comedy Central will book me if thisismewebsite.com, which I did register.

• 2:06Neil deGrasse Tyson?

  Oh, really?

• 2:09Janna Levin?

  We all froze for a second.

• 2:11Harrison Greenbaum?

  It's a very long domain. For some reason it was available.

• 2:13Janna Levin?

  There was a real beat there.

• 2:15Neil deGrasse Tyson?

  So, Jenna, you're an expert on the large-scale universe, on black holes.

• 2:20Janna Levin?

  Favorite.

• 2:21Neil deGrasse Tyson?

  Your recent book was The Black Hole Blues?

• 2:23Janna Levin?

  Yeah.

• 2:24Neil deGrasse Tyson?

  Yeah.

• 2:24Janna Levin?

  You know, you've said it better than anyone ever. I once got you to say the whole title, which you might not remember, was Black Hole Blues and Other Songs From Outer Space. And you did your best DJ voice nail. I can't, I don't know if I have it recorded.

• 2:35Neil deGrasse Tyson?

  Really?

• 2:36Janna Levin?

  Yeah.

• 2:36Neil deGrasse Tyson?

  Let me try it again. The Black Hole Blues and Other Songs From Outer Space.

• 2:44Neil deGrasse Tyson?

  Does that work for you?

• 2:45Janna Levin?

  It's really working for me.

• 2:46Neil deGrasse Tyson?

  Put that on your ringtone.

• 2:48Janna Levin?

  Exactly.

• 2:49Neil deGrasse Tyson?

  I'm a big fan of the blues in general, so I was enchanted by the title. So Harrison, if you remember, this is also not your first rodeo, but

• 2:56Harrison Greenbaum?

  Yeah.

• 2:56Neil deGrasse Tyson?

  you're not a regular on the show. For Cosmic Queries, we solicit questions from our fanbase through all the social media channels and then some. And you, the co-host, are the only one who's seen these questions.

• 3:08Harrison Greenbaum?

  That's right.

• 3:09Neil deGrasse Tyson?

  I haven't seen them, Jenna hasn't seen them, and you're just gonna read them. And Jenna and I will try to answer them. And if we can't answer, we'll just say, I'll say, "I don't know." She's not gonna say, "I don't know."

• 3:18Janna Levin?

  Oh, yeah, I might just make some stuff up.

• 3:22Janna Levin?

  Who's gonna call me out on it?

• 3:24Neil deGrasse Tyson?

  Maybe I'll call you out on it.

• 3:25Janna Levin?

  By then, I'll be home.

• 3:28Neil deGrasse Tyson?

  So Harrison, so what do you have for us?

• 3:29Harrison Greenbaum?

  Since you haven't seen these, I could just be making these up.

• 3:31Janna Levin?

  That's true.

• 3:32Neil deGrasse Tyson?

  That would be hard, though, I think. Yeah, yeah, all right.

• 3:34Harrison Greenbaum?

  All right, so we'll start with a-

• 3:35Neil deGrasse Tyson?

  We've got good people who listen to our stuff, so-

• 3:37Harrison Greenbaum?

  The first question says, "How do you make Harrison a regular?" That came from my mom. Definitely on the sheet. No, so here's a Patreon question.

• 3:46Neil deGrasse Tyson?

  Patreon?

• 3:46Harrison Greenbaum?

  Yes.

• 3:47Neil deGrasse Tyson?

  Oh, so you, out of all those questions, you went and found the Patreon question and put it first?

• 3:50Harrison Greenbaum?

  Absolutely, every time.

• 3:51Neil deGrasse Tyson?

  That is kissing ass. You realize this?

• 3:53Harrison Greenbaum?

  Gotta do it.

• 3:55Harrison Greenbaum?

  Zachary Spradlin from Patreon, and thank you for supporting. The question is, "Given your vast knowledge of physics," I'm sure they're talking to me. "What are your thoughts on a holographic universe? Would 100% empirical evidence of a holographic universe change how you behave on a day-to-day basis? Imagine if we could access the universal holographic database."

• 4:15Janna Levin?

  Whoa.

• 4:17Neil deGrasse Tyson?

  That's a good one.

• 4:18Janna Levin?

  It's like a three parter.

• 4:20Neil deGrasse Tyson?

  I've tried to fully understand the holographic universe and I only kind of skim the surface of it. So if you have a deeper.

• 4:26Janna Levin?

  It's pretty spectacular.

• 4:27Neil deGrasse Tyson?

  If you have a deeper sense of this, I would totally want to know.

• 4:29Janna Levin?

  Yeah, it's not something I specifically have worked on, but I pay very close attention to it in the hopes that one day I'll have a good enough idea to actually jump in the fray.

• 4:37Neil deGrasse Tyson?

  Okay, just to be clear, so when you do your work, you're a theorist.

• 4:39Janna Levin?

  Yeah.

• 4:40Neil deGrasse Tyson?

  And you're.

• 4:40Janna Levin?

  Very pen and paper.

• 4:41Neil deGrasse Tyson?

  Yeah.

• 4:42Janna Levin?

  Old fashioned.

• 4:42Neil deGrasse Tyson?

  Old fashioned.

• 4:43Janna Levin?

  Totally old fashioned, pen and paper.

• 4:44Neil deGrasse Tyson?

  So you're really cheap.

• 4:46Janna Levin?

  Yes.

• 4:46Neil deGrasse Tyson?

  You're a non-expensive scientist.

• 4:48Janna Levin?

  If you want to give me a grant, I can do my research.

• 4:52Neil deGrasse Tyson?

  Couple thousand dollars.

• 4:53Janna Levin?

  Seriously lowest level in terms of equipment and supplies. I think somebody will buy you a MacBook. Somebody'll buy you.

• 4:59Neil deGrasse Tyson?

  At least an iPad.

• 5:00Janna Levin?

  Yeah. And that's only to check my social media. A very large iPhone, we can get this done.

• 5:05Neil deGrasse Tyson?

  We got, you and I got this, we got this. So, so just so people know.

• 5:09Janna Levin?

  Yeah.

• 5:10Neil deGrasse Tyson?

  You're a professor of astrophysics at Barnard College in Columbia University.

• 5:13Janna Levin?

  Yeah.

• 5:13Neil deGrasse Tyson?

  Which is right up the street here, which is great. Okay, so, so go on, so.

• 5:16Janna Levin?

  So, um.

• 5:17Neil deGrasse Tyson?

  The holographic universe.

• 5:18Janna Levin?

  So hologram, the whole idea of a hologram is that you really have two dimensional information, but it creates the illusion of being three dimensional. That's just what a hologram means.

• 5:26Neil deGrasse Tyson?

  Yeah, because when you look at it, like.

• 5:28Janna Levin?

  Yeah.

• 5:28Neil deGrasse Tyson?

  Your, your, your credit card might have a holographic bird on it or something.

• 5:31Janna Levin?

  Right, but it's a two dimensional object.

• 5:33Neil deGrasse Tyson?

  Of course it's two dimensional because it's flat.

• 5:34Janna Levin?

  It's flat, but it looks like a full three voluined thing. Okay, so the reason why they, these physicists coined it holographic is precisely because they're imagining that all of the information that is required to understand the universe can be encoded on just a surface as opposed to in the full space. So for a black hole, this arose because if you look, a black hole doesn't physically have anything at its surface, but we imagine the event horizon as a surface, the, the region beyond which no information can escape. And the idea was that everything about the black hole, that all the information the black hole could possibly contain is equivalent to the amount of information that can be packed on the surface and nothing more.

• 6:18Janna Levin?

  And you cannot, and, and they've proven this over many years, back, back since Hawking, you cannot have more information than the information you can pack on the surface. And the reason why this.

• 6:28Neil deGrasse Tyson?

  You're saying more information can't get into the black hole than can be stored on the surface of the event horizon?

• 6:34Janna Levin?

  Yes, that, that you can prove that the information content of the black hole scales like the surface area of the black hole, the event horizon, and not like the volume. And so, the idea would be, well, we could maybe make an object.

• 6:46Neil deGrasse Tyson?

  He's shaking his head, yeah.

• 6:47Janna Levin?

  I saw that.

• 6:48Neil deGrasse Tyson?

  I did that calculation.

• 6:49Harrison Greenbaum?

  I like, I used to have those hologram stickers of like cats.

• 6:52Janna Levin?

  Yeah.

• 6:52Harrison Greenbaum?

  Does that get me anywhere close to understanding?

• 6:55Janna Levin?

  So, you know, it's one thing to kind of think about that, but then it took really years before people like Leonard Susskind started saying, oh, wait.

• 7:02Neil deGrasse Tyson?

  It's a physicist at Stanford.

• 7:03Janna Levin?

  He's a physicist at Stanford and just an incredibly creative thinker. And he-

• 7:07Neil deGrasse Tyson?

  Leonard Susskind.

• 7:08Janna Levin?

  Yeah. And great New Yorker from the Bronx was a plumber's son.

• 7:12Neil deGrasse Tyson?

  Bronx in the house.

• 7:12Janna Levin?

  Yeah.

• 7:13Harrison Greenbaum?

  The BX.

• 7:14Neil deGrasse Tyson?

  Bronx in the hologram.

• 7:15Janna Levin?

  He's got that tough guy accent still. So, um, so he really started to think about this, like, let's say I tried to have information that actually scaled like the volume, like, so that'd be a lot more information than you would think you could pack on the surface. And you can prove that, well, then you just make a black hole. And we know about black holes fundamentally, that you cannot have more information in the black hole than you can put on the surface.

• 7:36Neil deGrasse Tyson?

  But what does it mean to put information on a surface that does not exist?

• 7:39Janna Levin?

  That's very subtle. So it really, it's really the idea, I would, there's two ways to say it. One is to just say, oh, the information content of the black hole has been proven to scale like the area. And then the string theorist started to think, well, maybe that physically means it's like there on the horizon, that as-

• 7:55Neil deGrasse Tyson?

  The event horizon.

• 7:56Janna Levin?

  The event horizon, that as something falls into the black hole, um, it might appear to the poor astronaut that thinks they're falling into the black hole, uh, that they have crossed the event horizon and met their fate in the interior. But to us on the outside, it may appear, and this is a string theory suggestion, that it's actually physically smeared on the outside in the quantum string, um, states that are permitted on the outside and that it never gets inside.

• 8:20Neil deGrasse Tyson?

  So what about the fact that if I watch someone fall into a black hole, I see their time slow down?

• 8:25Janna Levin?

  Yes.

• 8:25Neil deGrasse Tyson?

  And as it, and at the event horizon, it has stopped.

• 8:28Janna Levin?

  Exactly.

• 8:29Neil deGrasse Tyson?

  So can we say that all this stops at the black hole as far as I can see?

• 8:32Janna Levin?

  I mean, it certainly is driven by some of those early, um, confusion about that. So it does seem, for as far as we're concerned, it never crosses.

• 8:41Neil deGrasse Tyson?

  Right.

• 8:42Janna Levin?

  Um, but to the astronaut themselves, they-

• 8:45Neil deGrasse Tyson?

  They just fall straight in.

• 8:46Janna Levin?

  They say, all right, true. So it's literally suggesting, like, quantum complementarity created this whole, there are two things that seem incompatible that can exist at the same time. It's literally suggesting that the astronaut both falls in and does not.

• 8:59Neil deGrasse Tyson?

  And it's smeared on the surface.

• 9:00Janna Levin?

  And smeared on the surface, but there's no single person in the universe who would be able to experience both things. So no single person has a contradiction.

• 9:10Janna Levin?

  Ooh, I see it's a-

• 9:11Harrison Greenbaum?

  When you talk about encoding information on the surface, you mean like the way like there's a California tattoo on Adam Levine? Where we know he's from California?

• 9:18Janna Levin?

  He's only tattoos on the surface.

• 9:20Neil deGrasse Tyson?

  That's all he is.

• 9:21Janna Levin?

  It looks like, it looks like a three dimensional body.

• 9:24Harrison Greenbaum?

  Yeah.

• 9:25Janna Levin?

  But it's really just skin tattoos.

• 9:29Neil deGrasse Tyson?

  So tell me something, if I think people freeze at the surface.

• 9:32Janna Levin?

  Yeah.

• 9:33Neil deGrasse Tyson?

  Then they're not living out their lives. We're living out our lives. How could we be in, every hologram I've seen, it's a, it's a frozen image. It's not, or it repeats in some trivial way.

• 9:44Janna Levin?

  So that's what we would see them freeze, you know?

• 9:46Neil deGrasse Tyson?

  But I'm not frozen, so how can I be a hologram?

• 9:49Janna Levin?

  So, oh, I see what you're saying, so, so it would be-

• 9:53Neil deGrasse Tyson?

  Wait, wait, I don't think I'm frozen.

• 9:56Janna Levin?

  So, um-

• 9:57Harrison Greenbaum?

  It's like the end of the Mary Tyler Moore opening credits where she like freezes.

• 10:00Neil deGrasse Tyson?

  Oh, she freezes there when she flips up her hat.

• 10:02Harrison Greenbaum?

  Is that what we're talking about?

• 10:03Neil deGrasse Tyson?

  How old are you?

• 10:05Harrison Greenbaum?

  I have no age.

• 10:07Neil deGrasse Tyson?

  We're just a fan of Mary Tyler Moore.

• 10:08Janna Levin?

  How do you get access-

• 10:09Harrison Greenbaum?

  We're at the edge of a black hole, so my life has just stopped.

• 10:11Neil deGrasse Tyson?

  1872, that show's been off the air, just want you to know.

• 10:14Janna Levin?

  So I would say the idea that holograms are frozen is just a technology problem. You certainly could make a hologram that was updating the information on the surface and therefore moving in time. So it doesn't have to be frozen to be a hologram, but it does have to be two dimensional and nonetheless appear three dimensional.

• 10:31Neil deGrasse Tyson?

  Why can't we be a three dimensional hologram of a four dimensional space? That's good, right?

• 10:37Janna Levin?

  Well, that's not, that's not bad, not bad, man.

• 10:39Neil deGrasse Tyson?

  The hologram is one dimension less.

• 10:40Janna Levin?

  Yes, it could be the case and there's definitely-

• 10:42Neil deGrasse Tyson?

  And aren't we four dimensions?

• 10:44Janna Levin?

  There, well-

• 10:44Neil deGrasse Tyson?

  Three space and one time?

• 10:45Janna Levin?

  Yeah, so there-

• 10:47Neil deGrasse Tyson?

  Don't go back on us on that one.

• 10:48Janna Levin?

  I'm not going back on you on that one, but there is some confusion about that time dimension, but there, but-

• 10:53Neil deGrasse Tyson?

  Whether it behaves as a space dimension.

• 10:54Janna Levin?

  It clearly does to some extent.

• 10:56Neil deGrasse Tyson?

  Whether it's a full blooded space dimension.

• 10:58Janna Levin?

  But to some extent it doesn't, because I can turn left and right, but I can't go for, in space.

• 11:02Neil deGrasse Tyson?

  Yeah.

• 11:03Harrison Greenbaum?

  I don't think my car has that sensor.

• 11:05Janna Levin?

  But I can't go forward and backward in time, right? So I can't, I can't do both directions in time.

• 11:09Neil deGrasse Tyson?

  You have mobility in space coordinates and not in time.

• 11:12Janna Levin?

  And I can see things in both directions. I can see something to the right and I can see something to the left. I can see something in the past where the light travels across the universe and gets to me, but I cannot see something from the future.

• 11:23Neil deGrasse Tyson?

  So we are prisoners of the present, forever trapped between a past we cannot access and a future we cannot see.

• 11:34Janna Levin?

  You're such a-

• 11:35Harrison Greenbaum?

  I think that's the new opening to the Twilight.

• 11:38Janna Levin?

  Cue the music.

• 11:41Neil deGrasse Tyson?

  Okay, so that's cool. So, so if we, so let's get back to the question.

• 11:45Harrison Greenbaum?

  Yeah.

• 11:45Neil deGrasse Tyson?

  If we know.

• 11:46Janna Levin?

  Just one question could keep us busy the whole time.

• 11:48Neil deGrasse Tyson?

  A hundred percent.

• 11:51Neil deGrasse Tyson?

  If we are a hundred percent sure that we are hologram, should we behave any differently?

• 11:55Janna Levin?

  Uh, that's.

• 11:56Neil deGrasse Tyson?

  And, and who are we a hologram to?

• 11:58Janna Levin?

  Yeah, so this is.

• 11:58Neil deGrasse Tyson?

  On whose black hole's surface are we?

• 12:01Janna Levin?

  Right, so then, well, so people have a harder time understanding holography in the cosmological context, moving away from the black hole. But the idea is the black hole is the terrain on which we learn fundamental thinking, so we should use the lessons that we can only learn there, the evidence that only exists there, to understand the whole universe.

• 12:18Neil deGrasse Tyson?

  As a cue?

• 12:18Janna Levin?

  Yeah.

• 12:19Neil deGrasse Tyson?

  As a, as proxy?

• 12:20Janna Levin?

  Right, so then we turn out, we say, "Ah, the universe is expanding so rapidly, we have a cosmic horizon."

• 12:24Neil deGrasse Tyson?

  We do.

• 12:24Janna Levin?

  We do. There is a region beyond which we cannot see as long as the universe expands at this pace, and the light can never get to us, race though it might, because the expansion of the universe will, will exceed it.

• 12:35Neil deGrasse Tyson?

  So we are analogous cosmologically to a black hole, and we are inside its event horizon?

• 12:39Janna Levin?

  Yeah, it's like an inverted one, and we're inside the event horizon, and there's stuff beyond it that we'll never know about us, and we'll never know about them. And so can we make a holography of that? And then, yes, can I make a holography of just you and I? But you see, we have so much less information than the maximum we could pack on us, that that's why we haven't tested whether or not we're holographic animals. So, a hol- you know, holography requires a more sophisticated thing than just like printing words in a book, which is not holographic, but it's way less than the maximum amount of information than you can pack. And the hologram is an example of packing a lot more, right? So if you made a human being that was packing the maximum amount of information that they possibly could, they would be turned into a black hole.

• 13:22Harrison Greenbaum?

  Or they'd have a really full backpack.

• 13:24Janna Levin?

  Yeah. So holography doesn't say you can't have things with less information that are just not, you know, as extraordinary. It just says that's, you know, that's the maximum that we can have. And so it's all an illusion. We really are two-dimensional.

• 13:36Neil deGrasse Tyson?

  You're flipping me out a little bit here. So just, let me just say, and I'm, and I'm an astrophysicist, right?

• 13:40Janna Levin?

  Yeah, right.

• 13:42Neil deGrasse Tyson?

  So, why did you all of a sudden, without anybody's permission in this conversation? Equate matter with information. Because when I think of matter, concentration of matter, as a star guy, I studied stars.

• 13:57Janna Levin?

  Yeah.

• 13:57Neil deGrasse Tyson?

  You pack in the matter.

• 13:59Janna Levin?

  Right.

• 13:59Neil deGrasse Tyson?

  And you get a black hole.

• 14:00Janna Levin?

  Right.

• 14:00Neil deGrasse Tyson?

  Now you're saying you're gonna pack information. And you're gonna get an information black hole. Is that the same thing?

• 14:05Janna Levin?

  I think that the shift that I'm feeling and that I'm learning from other people as well is that matter is just information. So what does it mean to say an electron is matter? What we mean is it has a certain charge. It has a certain spin. It has a certain number of quantum properties. And those quantum properties quantify as information.

• 14:24Neil deGrasse Tyson?

  And it completely defines what the thing is.

• 14:26Janna Levin?

  And there's no such thing as an electron that's a little bit heavier or a little bit lighter, spins a little faster, a little slower, has a little more charge or a little less charge. There's no such thing.

• 14:33Neil deGrasse Tyson?

  Every electron is identical to every other electron.

• 14:36Janna Levin?

  There's literally no history to it.

• 14:37Neil deGrasse Tyson?

  It's like all the Gargantuanians.

• 14:40Neil deGrasse Tyson?

  Which one is that one? The only thing that I need to know is its position in space.

• 14:44Janna Levin?

  Right, exactly. So the idea there is the electron is simply the collection of information about it. And that is its identity. And so then we start to think, well, what else does it mean to be physically real is just that list of quantum properties?

• 15:00Neil deGrasse Tyson?

  Wow.

• 15:01Janna Levin?

  So I think that the shift is to say, look, it's just math and information. And we gotta stop thinking so concrete, you know, feeling. Like, we know that this is an illusion. I can't put my hand through your leg, even though we both know it's mostly empty space on both parts.

• 15:14Neil deGrasse Tyson?

  We are mostly empty frickin' space.

• 15:16Janna Levin?

  Yeah, voids, two voids.

• 15:18Neil deGrasse Tyson?

  That's the secret to one of my tricks. It is. I won't tell you which one. Because you're also a magician, right? So, so there's a... It's all quantum. There's a famous comment, I'm gonna paraphrase it, and it might be apocryphal, but it's great anyway. Rutherford, was it Rutherford? Who discovered that the atom was empty? I think it was Rutherford.

• 15:34Janna Levin?

  Yeah, I mean, it was he did the nuclear stuff.

• 15:36Neil deGrasse Tyson?

  Yeah, yeah, okay. So what you do is you get a really thin gold foil, like aluminum foil, this is gold foil. Hammer it really thin. That's what I assume Trump grabs all his sandwiches.

• 15:46Janna Levin?

  I was gonna say, ah, this is a good one.

• 15:48Neil deGrasse Tyson?

  Very Trump, gilded, everything. So then you hang it there and you fire particles at it. And you ask... How often does a particle hit a gold atom? And how often does it pass through? Could you make it really, really thin? And it turns out, most particles pass right through the foil.

• 16:05Janna Levin?

  No damage done.

• 16:06Neil deGrasse Tyson?

  No damage done, not deflected, nothing. And he concluded that most of atoms are completely empty space. And he's rumored the next morning, after having contemplated this, that he was afraid to step onto the floor, getting out of his bed.

• 16:22Janna Levin?

  Ever feel the falling?

• 16:23Neil deGrasse Tyson?

  Fear he might fall through the floor. Because he alone, on Earth, knew how empty matter actually is.

• 16:32Harrison Greenbaum?

  I figured that out by looking at Republican heads.

• 16:35Harrison Greenbaum?

  Very empty.

• 16:36Janna Levin?

  Reading their tweets?

• 16:38Neil deGrasse Tyson?

  So is it fair then to say that... So in astrophysics, there's something called a degenerate state, which is not a statement about its moral fiber.

• 16:46Harrison Greenbaum?

  I would say most comedians are in a degenerate state.

• 16:48Neil deGrasse Tyson?

  Degenerate state has to do with whether two atoms or particles can occupy the same state at the same time, the same configuration. And electrons, two identical electrons cannot be in the same place at the same time. They have to be separated. And so there's a pressure because they will not... There's a limit to how close you can get them. And now, based on how you describe it, I'm thinking,

• 17:14Neil deGrasse Tyson?

  if you do that, you're putting too much information in one place.

• 17:16Janna Levin?

  Ooh, that's an interesting idea. Look at you, Neil. So the polyexclusion principle being caused by...

• 17:22Neil deGrasse Tyson?

  An information.

• 17:23Janna Levin?

  An information limit.

• 17:24Neil deGrasse Tyson?

  Want to write a paper on that?

• 17:25Janna Levin?

  That's do it. Oh my God. I'm gonna be up all night now.

• 17:28Neil deGrasse Tyson?

  Let's do that.

• 17:30Janna Levin?

  I love it.

• 17:30Neil deGrasse Tyson?

  All of the degenerate states. It's an information problem.

• 17:32Janna Levin?

  I think that's a lovely idea. We'll talk about that later.

• 17:35Neil deGrasse Tyson?

  We gotta take a break?

• 17:35Harrison Greenbaum?

  Do I get co-credit? Am I gonna be in a paper?

• 17:40Neil deGrasse Tyson?

  Yeah, and the credits, Harrison made us laugh during this.

• 17:43Harrison Greenbaum?

  Moral support. I was the cheerleader.

• 17:45Neil deGrasse Tyson?

  So when we come back, more Cosmic Queries, Out There edition.

• 18:02Speaker 03

  Unlocking the secrets of your world and everything orbiting around it. This is StarTalk.

• 18:18Neil deGrasse Tyson?

  We're back. StarTalk, Cosmic Queries, the out there edition. All parts of the universe that are far away and freaky. And we've got some good expertise for that in Janna Levin, Jenna. Good to have you, of course, Harrison. So this is the second segment, you're reading questions. The first segment, we got through only one question.

• 18:36Harrison Greenbaum?

  Yeah, but it was a doozy.

• 18:37Neil deGrasse Tyson?

  It was a doozy, all about holograms. So what else you have for us?

• 18:41Harrison Greenbaum?

  This is from Facebook, from Nate Gidioso, Gaudioso. And he said, "Could the entire known universe be the result of a white hole?"

• 18:50Neil deGrasse Tyson?

  Ooh.

• 18:50Janna Levin?

  You want to try it?

• 18:52Neil deGrasse Tyson?

  Ooh. Well, let me, let me put white holes on the map and then you take it from there.

• 18:56Harrison Greenbaum?

  Yeah.

• 18:57Neil deGrasse Tyson?

  So back in the 1970s, when the mathematics of black holes was being explored and formulated. It might have been late 1960s, but it was not deep back in the, in the century. It was like that late, if you will. People noticed that the equations that give you a black hole have a legitimate opposite solution to them. So let me test, Harrison, let me test your, your ninth grade math knowledge. You ready?

• 19:24Harrison Greenbaum?

  Okay.

• 19:24Neil deGrasse Tyson?

  Okay, what's the square root of nine?

• 19:26Harrison Greenbaum?

  Three.

• 19:27Neil deGrasse Tyson?

  Okay, so what's three times three?

• 19:29Harrison Greenbaum?

  Nine.

• 19:30Neil deGrasse Tyson?

  Okay.

• 19:33Neil deGrasse Tyson?

  What's negative three times negative three?

• 19:35Harrison Greenbaum?

  Also nine.

• 19:36Neil deGrasse Tyson?

  So nine has two solutions, doesn't it?

• 19:38Harrison Greenbaum?

  Right.

• 19:39Neil deGrasse Tyson?

  Square root of nine is negative three.

• 19:41Harrison Greenbaum?

  Plus or minus, yeah.

• 19:41Neil deGrasse Tyson?

  Yeah, and positive three. That's, well, you only gave me one solution.

• 19:44Harrison Greenbaum?

  Right.

• 19:45Neil deGrasse Tyson?

  The solution you preferred.

• 19:46Harrison Greenbaum?

  Yeah.

• 19:47Neil deGrasse Tyson?

  Right, but there's the, there's the dark side, the negative side. So some questions in science, the mathematics of them reveal that there are two answers that are completely authentic and legitimate. And when people were studying black holes and the mathematics of black holes, a second, in Einstein's equations, a second solution emerged. That was everything a black hole is, except the opposite of that. So things only ever came out of this space. And so it would be white if you were to look for it in the universe. So they said, let's look for these things. And people thought maybe quasars, which are very bright distant objects in the universe. Maybe those are the white hole versions of black holes. And then they said, we have a white hole and a black hole. Maybe they're connected.

• 20:31Neil deGrasse Tyson?

  And this was the introduction of a wormhole. Wormhole would connect a white hole to a black hole. Everything goes in a black hole, comes out the other side. So we looked for the properties of a white hole. Quasars did not satisfy those properties and we kind of gave up on them. So no one's looking for white holes anymore. So that's the farthest I can take it.

• 20:48Janna Levin?

  Wait, so it is a really intuitive idea that...

• 20:51Neil deGrasse Tyson?

  I got anything wrong? I think I got...

• 20:53Janna Levin?

  No, yeah, that sounds great. It's very natural to imagine. So let's say everything falls into a black hole and you think, it goes where? And that's the whole crisis about the black hole is not the event horizon and all that.

• 21:06Neil deGrasse Tyson?

  What's the thing? The whole crisis?

• 21:09Neil deGrasse Tyson?

  I didn't know.

• 21:10Janna Levin?

  I dropped the W.

• 21:11Neil deGrasse Tyson?

  The whole crisis.

• 21:12Janna Levin?

  The word must have gotten stuck in my head. So the idea would be that you can sew on a white hole onto the interior of a black hole. And it kind of makes sense because these singularities that people run amok on the streets because they don't, they don't want them to exist in nature and they probably don't exist in nature. And the singularities are so problematic that wouldn't it be better, instead of having this infinite energy, infinite curvature of space?

• 21:36Neil deGrasse Tyson?

  Infinite density.

• 21:36Janna Levin?

  Infinite density, literally a hole in space. Like the matter gets there in finite time and then what? You don't know what happens to it. It's literally like a cut in space. It's something where physics breaks down fundamentally. So people had the idea, well, let's get rid of the singularity and sew the black hole onto the Big Bang, which is also a singularity. And so you get rid of both and you repair it.

• 21:55Neil deGrasse Tyson?

  So you're saying at the center of the black hole, it birthed another universe?

• 21:58Janna Levin?

  Yes, so that is...

• 22:00Neil deGrasse Tyson?

  So casually she just said that.

• 22:03Neil deGrasse Tyson?

  I'm talking about invent a whole frickin' universe. Yeah, yeah, of course, you get a black hole.

• 22:07Janna Levin?

  Yeah, whatever.

• 22:08Harrison Greenbaum?

  I'm still stuck on the plus and minus, negative, the three.

• 22:11Janna Levin?

  What I, what I love the most about that is it means that the black hole, small as it might be on the outside. So let's say our, our sun became a black hole by, by some intervention, because it would naturally collapse to a black hole. It's not big enough, but if it were, it would be only about six kilometers across. You have very small object on the outside, but on the inside, it could be as big as a whole universe. So it's like Doctor Who's tar.

• 22:30Harrison Greenbaum?

  I was about to say, I was so excited, I was like, that really sounds like a tar.

• 22:34Neil deGrasse Tyson?

  Yeah, that's, that's, it's hit the geek buttons right there.

• 22:36Janna Levin?

  It's bigger on the inside than the outside suggests. And one way it could be big is it could be a whole big bang, it could be a whole universe. Now, the reason that's sort of fallen out of favor is because there are reasons to suggest that if that were true, that the universe would become very unstable to these things. Because if there's just some random probability for a black hole spontaneously creating a universe in its interior, it would be, even though seemingly unlikely, it would just be such a, what sort I'm looking for? Such a enormous proliferation of them that it would actually make the world unstable. And, and so it's sort of, it's sort of fallen out of favor. No, it depends on who you ask.

• 23:16Neil deGrasse Tyson?

  There's enough instability in the world.

• 23:18Harrison Greenbaum?

  I'm already in this for my new screenplay called The White Hole.

• 23:21Janna Levin?

  So, so, so some old fashioned relativists who only think about space and time still like the idea.

• 23:26Neil deGrasse Tyson?

  An expert on Einstein's relativity.

• 23:28Janna Levin?

  Yes, and, and studies primarily spacetime. And those who study things like string theory and particle physics are less, are more skeptical about the idea because their work seems to suggest this instability. So sometimes the camps are split on this still.

• 23:42Janna Levin?

  It can.

• 23:43Harrison Greenbaum?

  It could be a very tense dinner party.

• 23:46Janna Levin?

  Yeah.

• 23:47Neil deGrasse Tyson?

  So what you're saying is wherever there's a black hole, there's another universe.

• 23:50Janna Levin?

  If, if that's the case, yes.

• 23:51Neil deGrasse Tyson?

  This would be like a Swiss cheese in the higher dimensional.

• 23:55Janna Levin?

  That's right, but that universe, okay, so space and time switch places interior to the black hole. So while you're imagining a universe which is spatial, the black hole would be in its past and therefore inaccessible. So it, it would look like the big bang was solely in the past. It wouldn't be a place you could go to in the new universe. It would be a time in your history.

• 24:18Neil deGrasse Tyson?

  We gotta take a break.

• 24:19Harrison Greenbaum?

  And they're just now getting rid of CBD products in New York. Oh, man, my timing is terrible.

• 24:26Neil deGrasse Tyson?

  No, just if I repeat what I think I heard you just say. If you fall into a black hole, the universe you came from, you will see the entire future history of the universe unfold in front of you in an instant.

• 24:38Janna Levin?

  Yes. So the black hole's bright on the inside?

• 24:40Neil deGrasse Tyson?

  Bright, brighter, and bigger and brighter on the inside. Yeah, there you go.

• 24:44Janna Levin?

  Yeah.

• 24:45Neil deGrasse Tyson?

  All right, give me another question.

• 24:46Harrison Greenbaum?

  That's good. I just don't want to let any of the alt-right know about this white hole because they'll be like, "See, I told you, there's another one." All right. What's your, this is from a Patreon candidate, Frank, contributor, Frank Kane, which I think, is he related to Bob Kane? That's the guy who made Batman. What's, probably not, but Batman shout out. What's your take?

• 25:04Neil deGrasse Tyson?

  Probably not.

• 25:06Harrison Greenbaum?

  What is your take on negative mass? I've read that if it exists, we can hold open wormholes, travel backward through time, make a warp drive, and all sorts of crazy stuff. If the math said this is possible, do you think that means it really is possible?

• 25:18Neil deGrasse Tyson?

  Ooh. So start there first. If you have a mathematical understanding of a theory that is working, does everything that comes out of the math have to be true?

• 25:27Janna Levin?

  I mean, we don't obviously know the answer to that question, but it does seem like nature always finds a way. I mean, we've been sitting here talking about black holes.

• 25:38Janna Levin?

  So, black holes were originally just a thought experiment on paper, and Einstein thought nature would protect us from their formation. He didn't actually think they were really, he thought the math was accurate and beautiful and interesting and important, but not that it could possibly form.

• 25:52Neil deGrasse Tyson?

  He could have predicted black holes and just, the idea was so preposterous.

• 25:56Janna Levin?

  He literally put it, he literally said, "Oh, there's much more important things to think about right now." And the fact that nature figured out a way to make them by killing off a few stars is just kind of amazing, and it seems to happen over and over again, these seemingly implausible concepts. Um, end up being challenged by our limited, uh, you know, our limited intuition is challenged by, by nature actually doing it.

• 26:16Neil deGrasse Tyson?

  So the point is, the universe is big enough with enough things happening that even a completely rare thing is gonna happen.

• 26:22Janna Levin?

  Yeah.

• 26:23Neil deGrasse Tyson?

  Or unlikely thing.

• 26:24Janna Levin?

  Now, I'm gonna contradict myself and say now if I'm playing devil's advocate, I would say, um, you know, the square root of two, you asked about the square root of nine, the square root of two, I would say doesn't exist in physical reality as far as we know. It's only in our minds that it exists.

• 26:36Neil deGrasse Tyson?

  Right.

• 26:37Janna Levin?

  I can't make anything that has length square root of two, because it will eventually end at some finite digit, which is an approximation of square root of two, but it's not square root of two.

• 26:47Neil deGrasse Tyson?

  The, the, the decimals go on forever, like pi.

• 26:49Janna Levin?

  Yes, yes, irrational numbers, the decimals go on forever, but it, any length of anything or any measurement of any kind will only be a rational number and an approximate to an irrational maybe, so we can't measure pi ever, and we can't measure anything with, with square root of two length.

• 27:05Neil deGrasse Tyson?

  She's bumming me out.

• 27:06Janna Levin?

  And so, so then you can say.

• 27:07Neil deGrasse Tyson?

  Did you wanna, did you wanna measure pi? I wanna pi with diameter pi, so it just goes on forever. You'd always be baking it.

• 27:13Janna Levin?

  So you can say, well, that maybe I just gave you an example that proves that not every mathematical concept can be realized in physical reality.

• 27:21Neil deGrasse Tyson?

  Okay, but I'll give you a pass on that one.

• 27:23Janna Levin?

  Okay.

• 27:24Neil deGrasse Tyson?

  What do you call, in golf, what's it called, uh, give you a... Oh god, you're asking me sports question. I remember in high school, I went to the coach. A mulligan, give you a mulligan. A mulligan, there you go. There's your mulligan. So, so, alright, so now, tell, tell us about negative mass.

• 27:38Janna Levin?

  So negative mass is problematic.

• 27:39Neil deGrasse Tyson?

  Does it exist in anybody's formula?

• 27:41Janna Levin?

  Not that we know of. Um, we have seen negative energies in very subtle contexts where you have, um, two plates that are very close to each other, where you can create a negative energy in the quantum states between the plates.

• 27:53Neil deGrasse Tyson?

  So these are, this is when... I've dated some girls with negative energy.

• 27:56Janna Levin?

  Yeah.

• 27:57Neil deGrasse Tyson?

  So you're talking about like a capacitor plate, like metal plate?

• 28:00Janna Levin?

  Yeah.

• 28:01Neil deGrasse Tyson?

  You get really, really close.

• 28:02Janna Levin?

  Yeah.

• 28:03Neil deGrasse Tyson?

  So they're closer to each other than the... Wavelength of the particles in the matter that comprise them.

• 28:08Janna Levin?

  Yeah, in some sense, it's like saying if I can't have a water wave between two walls whose wavelength is longer

• 28:15Neil deGrasse Tyson?

  Than the width of the walls.

• 28:16Janna Levin?

  Than the width between the walls, exactly. I mean, not a standing wave. And so the idea is that it prunes some energy, meaning that in some sense, there's less states on the inside because of this than there are on the outside, where you have a whole continuum of possibilities.

• 28:29Neil deGrasse Tyson?

  So that's negative energy.

• 28:30Janna Levin?

  It can create, under certain circumstances, a negative energy, and then you will see a pressure on the plates. The plates will either push apart or move together.

• 28:37Neil deGrasse Tyson?

  If matter and energy are equivalent,

• 28:38Janna Levin?

  Yeah.

• 28:38Neil deGrasse Tyson?

  E equals mc squared.

• 28:39Janna Levin?

  Yeah.

• 28:40Neil deGrasse Tyson?

  If you're gonna give me negative energy,

• 28:42Janna Levin?

  Yeah.

• 28:42Neil deGrasse Tyson?

  why can't you hand me negative mass?

• 28:43Janna Levin?

  Yeah, I mean, it

• 28:44Neil deGrasse Tyson?

  There.

• 28:46Janna Levin?

  Well, here's, okay, so here's the problem with the negative mass is that it seems highly unstable. So if I literally had a particle, who's like the electron, whose fundamental mass was literally negative, and whose E equals mc squared energy was literally negative in that sense, then it would be possible to make tons of these and balance it with the generation of positive energy, respect conservation of energy, right? So then I could get an infinite energy resource by making negative energy particles, because that would have to, by energy conservation, lead to the creation of a positive energy somewhere. So runaway, our argument would be

• 29:27Neil deGrasse Tyson?

  And then when you bring them together, they annihilate, and then you have

• 29:29Janna Levin?

  Well, I don't know, maybe they're not antiparticles, maybe they don't annihilate, they just might have negative mass. So in other words, I could have zero energy in my laboratory, and I could have the best energy company conceivable.

• 29:39Neil deGrasse Tyson?

  Starting with zero energy.

• 29:39Janna Levin?

  Zero energy, it costs me nothing to make negative energy particles, because I just have to create, whether I like it or not, positive energy in response, meaning I can generate incredible positive energy at essentially no cost. And that is just not, it would be so unstable.

• 29:56Neil deGrasse Tyson?

  It's not stable in the universe.

• 29:57Janna Levin?

  It sounds good at first, like we power New York City at no cost. We get rid of fracking and coal and getting all of these fossil fuels, but we also destroy the universe in a completely unstable event where the negative energy runs out of control, creating infinite positive energy, and the whole thing blows up.

• 30:14Neil deGrasse Tyson?

  Harrison, I think it was It sounds like the plot of a supervillain. I think I've seen this in a Spider-Man film.

• 30:19Janna Levin?

  You were going to when this episode airs, I'm sure.

• 30:22Neil deGrasse Tyson?

  I think it was Kurt Vonnegut in one of his books, I don't remember which book, who said, "The last sentence ever spoken."

• 30:31Neil deGrasse Tyson?

  In the universe was by a scientist.

• 30:34Janna Levin?

  Was this in?

• 30:35Neil deGrasse Tyson?

  Who says to the other scientist, "Let's try it this other way."

• 30:41Janna Levin?

  Right.

• 30:42Neil deGrasse Tyson?

  This is the scenario you just described.

• 30:44Janna Levin?

  Yeah, exactly.

• 30:45Neil deGrasse Tyson?

  The whole universe goes unstable and disappears.

• 30:46Janna Levin?

  So some people say, "Look, I have an observation that proves that there's not negative mass particles, and that's the fact that the universe appears to be stable."

• 30:53Neil deGrasse Tyson?

  And we're here.

• 30:54Janna Levin?

  For eight, you know, for 14 billion years.

• 30:56Neil deGrasse Tyson?

  Wow.

• 30:57Harrison Greenbaum?

  Pretty good.

• 30:57Neil deGrasse Tyson?

  All right, give me another one.

• 30:58Harrison Greenbaum?

  All right, uh, we got Mike Berry.

• 31:00Neil deGrasse Tyson?

  This stuff is out there square.

• 31:02Janna Levin?

  I'm loving it. This is right up my alley.

• 31:03Neil deGrasse Tyson?

  Man.

• 31:04Janna Levin?

  I was worried you were gonna ask me about stuff that happened more recently than like half a billion years ago.

• 31:08Neil deGrasse Tyson?

  Oh, yeah, no, no, no.

• 31:09Janna Levin?

  In which case I'd be lost.

• 31:09Neil deGrasse Tyson?

  I'd take care of that one. I'm good with that. All right.

• 31:11Harrison Greenbaum?

  We got Mike Berry on Facebook, and he said, "I've never heard this explained. If the observable universe is roughly 15 billion years old, as we just said, and a star like ours lasts 12 billion, how can our sun be a third-generation star?"

• 31:24Neil deGrasse Tyson?

  Oh.

• 31:25Janna Levin?

  So I would say 14 billion is a little bit closer, a little bit less than 14 billion.

• 31:28Neil deGrasse Tyson?

  Yeah, so no.

• 31:29Janna Levin?

  But what's a billion among friends?

• 31:30Neil deGrasse Tyson?

  Between friends, between astronomers, if it's.

• 31:32Janna Levin?

  Yeah, among astronomers.

• 31:33Neil deGrasse Tyson?

  Yeah, we're, we're, we're around a third-generation star. So the life expectancy is not relevant to what generation you are. So there, because the generation that we speak of is, we think of the stars that create the elements that are then scattered back into the universe and give another generation this enrichment. Those stars live 100,000 million years.

• 31:57Janna Levin?

  Much shorter lived.

• 31:58Neil deGrasse Tyson?

  Much shorter lived.

• 31:58Janna Levin?

  They didn't have the heavy elements, precisely because they were first generation.

• 32:01Neil deGrasse Tyson?

  So you get the, the high-mass stars don't live very long.

• 32:05Janna Levin?

  They're made out of just nitrogen.

• 32:06Neil deGrasse Tyson?

  And fortunately, they blow up. If they didn't blow up, they'd keep their heavy elements, and the carbon, nitrogen, oxygen, silicon that's in our bodies would be forever locked in stars, and the universe would have never had life, would have, would not have even had planets. Because these high-mass stars make these elements and explode, scattering their enrichment across the galaxy, it enables the next generation of stars to have slightly more of this. The next generation of stars to have even more, so that you'd expect the frequency of planets and other interesting chemistry to take place with all the elements on the periodic table. The later your generation is, the more... Chemical latitude you have.

• 32:43Harrison Greenbaum?

  This is also the story of the Greenbaum family.

• 32:45Neil deGrasse Tyson?

  Oh, is that right?

• 32:46Harrison Greenbaum?

  A previous generation, living shortly, exploding.

• 32:48Neil deGrasse Tyson?

  Oh, I see. And you are particularly enriched.

• 32:51Harrison Greenbaum?

  Exactly, with a lot of chemical latitude.

• 32:53Neil deGrasse Tyson?

  We got time for one more before we take a break.

• 32:55Harrison Greenbaum?

  Sure, we got Jezebel Lorelei from Facebook, and she writes, what's the small-

• 33:00Neil deGrasse Tyson?

  That's a real name, Jezebel Lorelei. Whoa, that's a movie name right there.

• 33:04Harrison Greenbaum?

  Yeah. What's the smallest a black hole can be? And is there a name for the atom that is one neutron less than that atomic weight?

• 33:13Janna Levin?

  It's definitely less than a neutron's weight. What, so, no, wait, actually, it's not.

• 33:15Neil deGrasse Tyson?

  Are those, are those two different questions?

• 33:17Harrison Greenbaum?

  No, there's a comma in it.

• 33:18Neil deGrasse Tyson?

  There's a comma?

• 33:19Harrison Greenbaum?

  Those have been jammed together.

• 33:21Janna Levin?

  Don't you know the trick of answering the question you can and want to?

• 33:23Neil deGrasse Tyson?

  Yeah, yeah, okay.

• 33:24Janna Levin?

  Regardless of which one you can ask.

• 33:25Neil deGrasse Tyson?

  She can answer the one she knows she can answer. Okay, go.

• 33:27Janna Levin?

  So, um, I-

• 33:29Neil deGrasse Tyson?

  Just the smallest black hole.

• 33:30Janna Levin?

  I can't remember the actual number. So, we do know, it is conceivable, that a microscopic black hole could be made under very extraordinary conditions. Now, we say that the limit of the mass of it is related to the strength of gravity, and that gives us a scale of how, how heavy it could be. And it's heavy compared to things like electrons, but it's incredibly light compared to, um-

• 33:52Neil deGrasse Tyson?

  Golf balls.

• 33:53Janna Levin?

  Anything, right, else on the, uh, exactly. So, I think it's about the weight of a little pile of sand. Imagine a modest pile of sand. That would be about the weight it could maintain and be consistent with what we think is the limit of the strength of gravity, and it would be an incredibly tiny microscopic black hole. I mean, I can't even, I'm-

• 34:16Neil deGrasse Tyson?

  Oh, that'd be really small, yeah.

• 34:17Janna Levin?

  It'd be, it would be really small.

• 34:21Neil deGrasse Tyson?

  But wait a minute.

• 34:22Janna Levin?

  I should know the number, 10 to the, what, what is it? 10 to the minus 45 seconds after the Big Bang is around the time of quantum gravity. So, if I multiplied that maybe by the speed of light, I would roughly get the size of the black hole or something like that. But anyway, you can ask me, ask me later. I'll crunch some numbers.

• 34:37Neil deGrasse Tyson?

  Okay. 10 to the minus 15 meters or something. So, but, but- Black holes evaporate, so they can become so small that they don't exist at all.

• 34:44Janna Levin?

  Well, those, oh, good point. So those black holes are incredibly unstable to evaporation. Because the, um, the idea that Hawking, uh, foisted on us-

• 34:52Neil deGrasse Tyson?

  The late Stephen Hawking.

• 34:53Janna Levin?

  The late Stephen Hawking, um, the amazing Stephen Hawking, that black holes, although they let nothing out, they somehow still evaporate, that tremendous paradox that we've been grappling with since the seventies. Um, he also realized that the temperature is colder the bigger the black hole. So they evaporate more slowly, the bigger they are. So we've never seen an astrophysical black hole evaporate, because they're way too cold for us to perceive for evaporation.

• 35:14Neil deGrasse Tyson?

  The big ones, yeah.

• 35:14Janna Levin?

  The big ones that are made by dead stars. A microscopic one made in the early universe would presumably evaporate in an instant. And it would be, it would, so people have looked for that. They've looked for little explosions, high-energy explosions in the very early universe to see if there were primordial black holes.

• 35:29Neil deGrasse Tyson?

  Gamma-ray bursts, small bursts. But yeah, we haven't found them, though.

• 35:31Janna Levin?

  Yeah.

• 35:31Neil deGrasse Tyson?

  Yeah, yeah. Oh, right. Yeah, we gotta wrap up this segment of Cosmic Queries, the Out There Edition. We'll be right back.

• 35:56Neil deGrasse Tyson?

  StarTalk, Cosmic Queries, the Out There Edition. This is the first time we've done an Out There Edition. I think we have to do this more often.

• 36:02Janna Levin?

  This is fun.

• 36:03Neil deGrasse Tyson?

  And Janet, you're like a neighbor up the street at Barnard in Columbia, so-

• 36:06Janna Levin?

  Yeah, absolutely. I just take a stroll-

• 36:09Neil deGrasse Tyson?

  Yeah, yeah, we'll have to like have a little bat signal.

• 36:11Janna Levin?

  Yeah.

• 36:12Neil deGrasse Tyson?

  Are you out there? We need you here for an out there. Ed Harrison, again, thanks for being on StarTalk.

• 36:18Janna Levin?

  My pleasure.

• 36:18Neil deGrasse Tyson?

  So you got Cosmic Queries for us?

• 36:20Janna Levin?

  Oh, yeah.

• 36:20Neil deGrasse Tyson?

  What more do you have?

• 36:21Harrison Greenbaum?

  Uh, we got-

• 36:21Neil deGrasse Tyson?

  Let's make this entire segment the lightning round.

• 36:24Janna Levin?

  Absolutely. Oh, we're gonna be faster and faster.

• 36:25Neil deGrasse Tyson?

  They used to give me a bell. I don't know what happened to my bell. But a lightning round, so this will just be more soundbite answers, just so we can get to more questions.

• 36:32Janna Levin?

  Totally.

• 36:32Harrison Greenbaum?

  Absolutely. So we have Tony underscore LE738 on Instagram says there's an opposite to a black hole that just spews out things.

• 36:39Janna Levin?

  White hole.

• 36:40Harrison Greenbaum?

  There we go, perfect.

• 36:42Neil deGrasse Tyson?

  Been there, done that.

• 36:43Harrison Greenbaum?

  I think it just spews out endless garbage. Trump, okay. Um, Ben Ratner, at BenMakesTV on Twitter, what is your favorite recipe for a good soup?

• 36:51Neil deGrasse Tyson?

  Primordial soup.

• 36:53Harrison Greenbaum?

  Nice.

• 36:54Neil deGrasse Tyson?

  Uh, yeah. Uh, for me, a good soup would be all the basic ingredients that are the foundational to biochemistry. Carbon, nitrogen, oxygen.

• 37:07Neil deGrasse Tyson?

  Carbon is the stickiest element on the entire table. It can make more kinds of molecules than any other elements combined. So, give me a soup with carbon, nitrogen, oxygen in it, and I can show you life. So, I just happen to have a can of primordial soup on my shelf. For those who don't have video, it's Wallace's condensed primordial soup.

• 37:34Janna Levin?

  Can you read the ingredients on the primordial soup?

• 37:36Neil deGrasse Tyson?

  The ingredients, I used to be able to, let's see.

• 37:38Janna Levin?

  Is this a real one?

• 37:39Neil deGrasse Tyson?

  Oh yeah, okay. Quick and easy instructions: mixed soup, one can of seawater, okay? Lightning, heat, uncovered in early years. This goes, this is like the early Earth here. For two to three millennia, save the simple molecules to form larger, more complex molecules. For a creamier soup, use one can of organisms. So, yeah, that's that, so that'd be the best kind of soup at all.

• 38:12Harrison Greenbaum?

  I prefer a split pea.

• 38:13Neil deGrasse Tyson?

  All right, keep going, Harrison.

• 38:14Harrison Greenbaum?

  All right, we got Joshua Willham from Facebook.

• 38:16Neil deGrasse Tyson?

  We're still in quick mode, lightning mode.

• 38:18Harrison Greenbaum?

  If you could subtly know the answer to any question, what question would you choose?

• 38:22Janna Levin?

  Subtly knowing the answer is so disappointing. As a scientist, the whole fun is figuring it out. I don't know if I'd subtly want to know the answer to any question other than when's my Uber coming? Or some...

• 38:33Harrison Greenbaum?

  I think you just have to look at your phone?

• 38:36Neil deGrasse Tyson?

  Yeah, that's not a mystery on that one.

• 38:37Harrison Greenbaum?

  Although they have physics that are unbelievable, where like the car just jumps through a building? And you're like, that was, that was some physical possibility.

• 38:45Neil deGrasse Tyson?

  Or just does it flip around and, you know?

• 38:46Harrison Greenbaum?

  Did Uber discover a black hole in the city? I don't know how it jumped a...

• 38:49Neil deGrasse Tyson?

  Wormhole, a wormhole through the building. So, for me, the answer I want is to the question we don't know yet to ask. Because the day we learn what that question is... I no longer care. I will wait, await the day where the next question comes that I didn't know to ask. And this is strongly resonant with Jana's answer. Where the quest to the answer, science is not so much about answers, but the search for answers. And that's where you learn, you stumble on things, you discover the structures of things you didn't even know that was a question you needed to ask. So, yeah, I'm all, I'm all into the search. So these are-

• 39:31Janna Levin?

  I'd like to have the answer, just not suddenly.

• 39:34Neil deGrasse Tyson?

  Oh, not-

• 39:34Janna Levin?

  I don't want it to be never either. Never is frustrating.

• 39:37Neil deGrasse Tyson?

  Very good. That's very healthy posture. Otherwise, there's a psychological problem you have.

• 39:41Janna Levin?

  Yeah, exactly.

• 39:42Harrison Greenbaum?

  I like your escape room, so within 60 minutes, that's generally when I get the answers. All right, we got Scott York at Instagram. Could dark matter or dark energy be any indication of alien technology that is beyond human comprehension?

• 39:53Neil deGrasse Tyson?

  Ooh. Go. Don't look at me.

• 39:57Janna Levin?

  This feels more like an, yeah.

• 39:58Neil deGrasse Tyson?

  Okay, here's what I was, I'll give my answer, and then why don't we hear your answer, okay? Just because there's something in the universe we don't understand? Doesn't mean it's aliens. It doesn't mean it's magic.

• 40:10Janna Levin?

  Otherwise, my VCR was made by aliens.

• 40:13Harrison Greenbaum?

  You still have a VCR?

• 40:14Janna Levin?

  Exactly. The fact that I have a VCR-

• 40:16Harrison Greenbaum?

  Oh my God, we really need to get you that grant. My God.

• 40:18Janna Levin?

  It would reflect alien intervention somehow.

• 40:20Neil deGrasse Tyson?

  First, you're talking about Mary Tyler Moore, and you're talking about VCRs. How the hell old are you guys?

• 40:25Harrison Greenbaum?

  I'm sorry, my beeper went off.

• 40:28Neil deGrasse Tyson?

  Beeper? So, um, so I think, wait, what was the question again?

• 40:34Janna Levin?

  Uh, could dark matter and dark energy be evidence of aliens?

• 40:37Neil deGrasse Tyson?

  It's tempting, it's always tempting to ascribe something completely extraordinary as the cause for something we don't understand. We've been doing that forever. But as a scientist, you have to resist that because the history of that exercise is one of abject failure persistently. So to say, oh, it's actually magic, or it's actually God, or it's actually an alien, and then you study it, and it's, it's reducible to known forces, or maybe you'll discover a new force, but it's still not magic, it's still not God, and it's still not aliens. So-

• 41:10Neil deGrasse Tyson?

  If I'm betting, I would say it's probably not as much as we would really love it to be.

• 41:15Janna Levin?

  Now, the place we should be looking for aliens is a place we actually know where to look, which is on exoplanets, where there really is a very serious prospect that there are aliens.

• 41:23Neil deGrasse Tyson?

  These are planets orbiting other stars.

• 41:25Janna Levin?

  Yes, exactly. Planets orbiting other stars. We think that in our Milky Way, of which there are hundreds of billions of stars, that there are probably more planets than there are stars in the Milky Way. And so that's suddenly a stunning number that we didn't realize, what, 20 years ago?

• 41:41Neil deGrasse Tyson?

  Yeah, but you're just talking about some kind of living organism.

• 41:43Janna Levin?

  Right, I was gonna say, don't be disappointed.

• 41:45Harrison Greenbaum?

  Talk to them.

• 41:46Neil deGrasse Tyson?

  Serious ray gun aliens, you know?

• 41:49Harrison Greenbaum?

  Absolutely.

• 41:50Janna Levin?

  The aliens, right.

• 41:51Harrison Greenbaum?

  Air 51.

• 41:52Janna Levin?

  I know. They're probably more like the kind of thing you wipe off your shoe, which is sad.

• 41:56Neil deGrasse Tyson?

  Exactly. Some primordial ooze that is itself a mat of life. That's so, you're so unfun with that. It's true, but unfun.

• 42:05Harrison Greenbaum?

  All right, Kay Futch from Instagram, how many black holes are there?

• 42:09Janna Levin?

  So, in our galaxy, we just said that there are a few hundred billion stars in our galaxy. About 1% of them at the end of their lives are going to be big enough to collapse all the way through to become black holes. And so, that's a lot, right?

• 42:20Neil deGrasse Tyson?

  Yeah, 1% of 100 billion is a billion black holes.

• 42:22Janna Levin?

  It's a billion black holes. And in addition to that, we know that there are tens of thousands of black holes around the supermassive black hole at the center of our galaxy. So, the center of our galaxy harbors a black hole a few million times the mass of the sun, and it has tens of thousands of black holes specially segregated around it. So, that's just our galaxy. Now, you're saying in the observable universe there are as many galaxies as there are stars in the Milky Way. You've got a lot of black holes out there.

• 42:44Neil deGrasse Tyson?

  And all evidence shows that every red-blooded galaxy, like the Milky Way, has got a supermassive black hole in its center. So...

• 42:51Janna Levin?

  So, we've got hundreds of billions of those, and hundreds of billions times a billion of the smaller ones.

• 42:58Neil deGrasse Tyson?

  Surrender now.

• 43:00Harrison Greenbaum?

  The worst Milky Way, like a Milky Way candy bar that's realistic, has a black hole in the middle of it. No, thank you. Jeek dot 2 at Instagram wrote, "Can a black hole eat another black hole? And if so, would it contribute to its growth?"

• 43:14Janna Levin?

  Absolutely.

• 43:15Harrison Greenbaum?

  Like a Pac-Man theory of black holes.

• 43:16Janna Levin?

  Absolutely. One of the most...

• 43:17Neil deGrasse Tyson?

  Pac-Man? Wait, you referenced this so...

• 43:20Janna Levin?

  Pac-Man!

• 43:21Neil deGrasse Tyson?

  Classic. Oh, I love it. But I have to make fun of it, because we got...

• 43:24Janna Levin?

  Can we come to your house and see what you've got the setup there? This is a lot.

• 43:28Harrison Greenbaum?

  I've done a couple of 80s escape rooms recently, so it's on my mind.

• 43:30Janna Levin?

  Do you have a cellphone?

• 43:34Harrison Greenbaum?

  It's very large.

• 43:34Janna Levin?

  Wait, why was it... Oh yeah, black holes eating other black holes. That is, one of the most exciting things that's happened this century is the direct recording of the sound of spacetime ringing due to the collision of two black holes, which, if you wanted to call it them eating each other, you could. They merged and they created a bigger black hole. So each one was about 30 times the mass of the sun. And so we know that there's a black hole out there in that rough direction, as far as we could ascertain, that is 60 times the mass of the sun. And yes, they get bigger. They get bigger by almost as much as you would think. The energy that they lost in terms of like, literally, E equals mc squared energy, that wasn't the sum of the parts, came out in this ringing of spacetime. And it was recorded by LIGO, this fantastic instrument. It happened in, must have been 2015.

• 44:19Neil deGrasse Tyson?

  It's a new window to the universe that's measuring the ripples in the fabric of space, rather than the ripples in the energy of light.

• 44:25Janna Levin?

  And this is what Black Hole Blues was all about. I was writing it while they were on this campaign.

• 44:28Neil deGrasse Tyson?

  Your book.

• 44:29Janna Levin?

  Yeah, and they hadn't succeeded while I was writing it. And I was really writing it, precisely ties in with what we were talking about earlier, about the pursuit. And, you know, it was 50 long years that they strove to build this instrument and make this detection.

• 44:40Neil deGrasse Tyson?

  So, wait a minute. The title of your book is Black Hole Blues. Is that because you didn't think they would find it?

• 44:44Janna Levin?

  Yeah.

• 44:45Neil deGrasse Tyson?

  And then they found it, and now your book has the wrong title.

• 44:47Janna Levin?

  Yeah, so amazingly, Ray Wise, who won the Nobel Prize alongside Kip Thorne and Barry Barish for that discovery, said to me about a month before the detection occurred, "If we don't detect black holes, this thing is a failure." And so I got the title really thinking about Ray saying that. That he's now in his 80s, he started this as a young man, and it was the Black Hole Blues. But they told me, well before the book, you know, came out, they told me about the detection. So I didn't want to rewrite it because I think it is all about the pursuit, but I do have a lovely close where they make the discovery.

• 45:18Neil deGrasse Tyson?

  Okay, I didn't get to that close yet in your book. Now I'm gonna go ahead to find it. Right, right. All right, give me more.

• 45:24Harrison Greenbaum?

  All right, we got Michelle Akempora from Facebook. If everything is supposed to be expanding away from each other, how come our galaxy is on a collision course with Andromeda?

• 45:32Neil deGrasse Tyson?

  Okay, I got this. I got this.

• 45:35Janna Levin?

  I'm gonna have to throw down afterwards.

• 45:36Neil deGrasse Tyson?

  I got this. So the expansion of the universe is, think of it as a stretchy fabric that if, and it doesn't matter where you are, you'll think you're at the center of that stretching, and you'll see objects moving away from you in every direction. Objects that are near you will not be moving away as fast as objects that are farther away. Because every, let's say for every meter it stretches 10 centimeters, okay? Well, that means at 2 meters it stretches 20 centimeters. At 3 meters it's 30 centimeters. That's how stretching works in the fabric. So, all galaxies have speeds relative to each other.

• 46:15Neil deGrasse Tyson?

  If you have a nearby galaxy, it's going faster than the stretching speed of the universe in this space, in the space near me. So, my gravity overcomes anything the universe is doing for things nearby. So, nearby galaxies are going on like the universe is not expanding, they don't really care. Their gravity is strong enough to create motions that overcome the expansion of the universe itself. But we're not going to collide with a distant galaxy because the stretching of the universe is taking us away faster than that can ever happen.

• 46:50Janna Levin?

  I just wanted to make reference to, I think it's Annie Hall, the line where, um...

• 46:55Neil deGrasse Tyson?

  Oh, okay, go on.

• 46:56Janna Levin?

  The character, um, won't do his homework because he's...

• 46:59Neil deGrasse Tyson?

  The kid, the kid.

• 47:00Janna Levin?

  Because the universe is expanding.

• 47:01Neil deGrasse Tyson?

  Yes.

• 47:02Janna Levin?

  And he's, and his mother says, "You live in Brooklyn, Brooklyn is not expanding." And it's true, Brooklyn is not expanding for precisely the reasons Neil just gave. That, that the Earth is bound together more strongly than the expansion can tear it apart.

• 47:14Neil deGrasse Tyson?

  In this, in this section, yeah, this expanding universe is not going to break apart the Earth.

• 47:19Harrison Greenbaum?

  Yeah. And now a bunch of developers have brought Brooklyn and it is expanding at an incredible pace. Alright, so we got, uh...

• 47:24Neil deGrasse Tyson?

  It's gotta be fast.

• 47:25Harrison Greenbaum?

  Kyle Toth from Venice, Florida. Uh, what lies beyond the observable universe? Do we have an estimated size of the entire universe?

• 47:33Neil deGrasse Tyson?

  Ooh.

• 47:34Janna Levin?

  I love this.

• 47:34Neil deGrasse Tyson?

  Dana, take it. And by the way, we were still kind of in speed mode.

• 47:37Janna Levin?

  Yeah.

• 47:38Neil deGrasse Tyson?

  But we're going to end with your answer to this question.

• 47:40Janna Levin?

  Okay, lovely.

• 47:41Neil deGrasse Tyson?

  No pressure.

• 47:42Janna Levin?

  That's a lot of pressure, a lot of pressure. Um, it is conceivable, uh, that the universe is actually finite. And the same sense that the earth is finite. If I leave New York City and I walk in a straight line as possible, and I go for as long as I possibly can, I come back to New York City again. It is conceivable-

• 47:57Neil deGrasse Tyson?

  Without ever falling off an edge.

• 47:58Janna Levin?

  Without ever turning left or right, falling off an edge, going forward and backward.

• 48:01Neil deGrasse Tyson?

  So you can walk forward forever?

• 48:03Janna Levin?

  Forward forever.

• 48:04Neil deGrasse Tyson?

  In a finite space.

• 48:05Janna Levin?

  And just keep coming back around and around and around again. Now, if the whole universe is like this, I literally would leave the Milky Way in a spacecraft. I would travel in a straight line, watch the galaxy recede behind me, not turn left, not turn right, never stop forward, not fall off the edge of the universe, but see the Milky Way approach in front of me again.

• 48:22Harrison Greenbaum?

  Wow. How many, how many-

• 48:24Neil deGrasse Tyson?

  We need a mic drop on that. Right, right, here, drop.

• 48:27Harrison Greenbaum?

  There you go.

• 48:29Janna Levin?

  Could you hear it?

• 48:29Neil deGrasse Tyson?

  That was an audio mic drop, right there.

• 48:31Harrison Greenbaum?

  How many seasons of this podcast would you have to listen to before you saw the Milky Way again?

• 48:35Janna Levin?

  That's right. We would look back, and because light has a finite travel time, we would hear podcasts from our past. Like, you could look back and see yourself as a child if you waited long enough for the light to come back around again.

• 48:49Neil deGrasse Tyson?

  From the other direction.

• 48:50Janna Levin?

  From the other direction.

• 48:51Neil deGrasse Tyson?

  Yeah.

• 48:51Janna Levin?

  And, um, and so we could actually resolve serious quandaries by being like, "Well, if we wait a billion years, we can actually watch it again."

• 48:59Neil deGrasse Tyson?

  Just to get the argument straight about who said what-

• 49:01Janna Levin?

  Exactly.

• 49:02Neil deGrasse Tyson?

  Over dinner.

• 49:04Janna Levin?

  Who broke the plate, right?

• 49:06Harrison Greenbaum?

  There's this sad old astronaut alone, like, "I told you, Jamis." This was all worth it.

• 49:12Neil deGrasse Tyson?

  So, so, okay, so that's a finite universe, but just as equally, the universe could be infinite. And we're just our own observable pocket within some infinite universe.

• 49:22Janna Levin?

  Right. It is also possible, and that the universe is infinite, and beyond the observable universe is this infinite stretches space. But, you know, Einstein said only two things are infinite, the universe and human stupidity. And then he said, "I'm not so sure about the universe."

• 49:39Neil deGrasse Tyson?

  That sounds like we should end on that. No, doesn't it?

• 49:40Harrison Greenbaum?

  Einstein mic drop.

• 49:43Neil deGrasse Tyson?

  Janet, it's great, and I've been loving your book-

• 49:45Janna Levin?

  Thanks, it was fun.

• 49:46Neil deGrasse Tyson?

  The Black Hole Blues.

• 49:47Janna Levin?

  Thank you.

• 49:49Neil deGrasse Tyson?

  Harrison, thanks for coming back on StarTalk.

• 49:50Harrison Greenbaum?

  My pleasure.

• 49:51Neil deGrasse Tyson?

  And HarrisonGreenBound.com. We'll look for your, for your stand-up gigs, and you're also a magician.

• 49:57Harrison Greenbaum?

  Absolutely.

• 49:57Neil deGrasse Tyson?

  And I've been your host, Neil deGrasse Tyson. This has been StarTalk. And as always, I bid you to keep looking up.