Cosmic Queries – Quantumly Stupid

What would a four-dimensional being see if it looked at us? In this episode, Neil deGrasse Tyson and Chuck Nice answer fan questions covering higher-dimensional surgery, space elevators, alien intelligence, and colliding galaxies. Could spacetime itself be a cosmic crystal?

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

• 0:00Neil deGrasse Tyson?

  Chuck, every time we do a Grab Bag Cosmic Queries, the level of the question is getting higher and higher.

• 0:06Chuck Nice?

  I know, I might have to go back to school.

• 0:11Neil deGrasse Tyson?

  I have to bring in some big guns next time.

• 0:14Chuck Nice?

  Yeah.

• 0:14Neil deGrasse Tyson?

  Man, I'm loving it, though.

• 0:16Chuck Nice?

  Yeah, it's good stuff.

• 0:17Neil deGrasse Tyson?

  Yeah, yeah, all right. Coming up next.

• 0:22Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide.

• 0:31Neil deGrasse Tyson?

  StarTalk begins right now.

• 0:36Neil deGrasse Tyson?

  This is StarTalk Cosmic Queries. I got with me Chuck Nice.

• 0:41Chuck Nice?

  Hey, what's happening, Neil?

• 0:43Neil deGrasse Tyson?

  All right, there's a Grab Bag.

• 0:44Chuck Nice?

  Yes, it is.

• 0:45Neil deGrasse Tyson?

  What's the verdict on how long it takes me to answer a question?

• 0:49Chuck Nice?

  Believe it or not, because they put out this to the audience, they like the longer answers.

• 0:54Neil deGrasse Tyson?

  The producers?

• 0:55Chuck Nice?

  Well, the producers want us to go, want us to go as quickly as possible because they want to get more answers in.

• 1:01Neil deGrasse Tyson?

  Yeah.

• 1:01Chuck Nice?

  That was the, but they asked the people and the people liked the long answers.

• 1:05Neil deGrasse Tyson?

  And people spoke.

• 1:06Chuck Nice?

  Yes, the people have spoken.

• 1:07Neil deGrasse Tyson?

  Have risen up.

• 1:08Chuck Nice?

  That's right.

• 1:09Neil deGrasse Tyson?

  All right. I won't do it on purpose. It's just, it's, it's, it's organic when it happens.

• 1:14Chuck Nice?

  It's the passion, the passion of the universe flowing through me. This is Alex Kay, who says, hello, Dr. Tyson Lord Nice. Alex from Bucharest, Romania here.

• 1:24Neil deGrasse Tyson?

  Bucharest.

• 1:24Chuck Nice?

  Bucharest. What keeps me up at night is Flatlanders and 4D space. I often hear.

• 1:31Neil deGrasse Tyson?

  Ah, I love, that's, says some geeky stuff right there. That's, that, we get, give him a geek award for that.

• 1:39Chuck Nice?

  He says, I often hear that dark matter or dark energy could be the 4D leaking into our 3D space. But living in 3D space, can we ever actually observe a truly 2D space? And if not, wouldn't that mean 4D beings couldn't interfere with our world either? Just as we don't notice any real 2D beings?

• 2:06Neil deGrasse Tyson?

  I see where he's coming from. Yeah. I think. What he's saying is, if there were 2D creatures in our world, how would we ever know? Right. All right. So, holding aside the fact that if you're 2D, you have no thickness. Right. If you have zero thickness, how does any light or matter even interact with you? Because light and matter. Reflect. Yeah, okay. But so, let's just ignore that very real complication, but let's ignore it for the moment. Okay. Okay? There was a cartoon, back when the internet was a fun place to just explore humor and cat videos. Oh, yeah. There was a. Those were the days.

• 2:47Neil deGrasse Tyson?

  There were two illustrated creatures, and one of them was 2D. I forgot their names. It's like, "Hey Joey, I just became 2D." And he's looking at him. He looks a little flat, but, but he wasn't sure. And all he did was turn sideways and he disappears. Disappears. Disappears. He turned sideways towards your sight line. Right. And then they laughed, and they were just having a good time. Those were the days on the internet. Man. Yeah. Man. Now it's nothing but Nazis.

• 3:21Neil deGrasse Tyson?

  It's Nazi-yacy. Okay.

• 3:28Neil deGrasse Tyson?

  So, it implies that even if you're invisible edge on, that the light is somehow still reflecting off of you face on. Right. Okay? So, a 2D world in front of us would be completely visible. You would see light reflecting off of their substance. Right. Their 2D substance, whatever that is. Right. Only when they go sideways do they disappear. Okay. From your view. Right. Because they have no thickness. So, we three-dimensional creatures.

• 3:59Neil deGrasse Tyson?

  What would, would four dimensional, spatial dimensional creatures be able to see us? It means there must be some orientation we can take where we disappear to them.

• 4:10Chuck Nice?

  Right.

• 4:10Neil deGrasse Tyson?

  Just following this, this sequence. I don't, I can't picture what that would be.

• 4:16Chuck Nice?

  Yeah, well, yeah, you know, I, I can't either because I'm 3D.

• 4:23Chuck Nice?

  I'm looking around, everything's 3D. You know, what do I look like to a 4D guy? I don't know, you know?

• 4:31Neil deGrasse Tyson?

  I don't know how a 3D person would hide from a 4D person, which way to orient ourselves. The way a 2D person can do that to us. I don't know how you do that. I have to think about it some more. What I do know is, and we've said this before, if you're looking at a 2D creature, you can see inside their organs, their inner organs. 2D people can't see because they have skin, this line, which is their 2D skin. They can't see through the line, but we can see directly into their bodies.

• 5:00Chuck Nice?

  So I, I look really ugly to a 4D person?

• 5:03Neil deGrasse Tyson?

  4D person, they see, they'll see all your guts.

• 5:04Chuck Nice?

  They just see guts and yeah.

• 5:07Neil deGrasse Tyson?

  And I think the first thing we do when we have four dimensional beings is to make the medical doctors and have them perform surgery.

• 5:15Chuck Nice?

  Right. It's a game of operation for them. Nothing to it. Take out wrenched ankle. Good to go.

• 5:24Neil deGrasse Tyson?

  Forgot about that game, operation. I wonder how many people can be doctors out of that.

• 5:30Chuck Nice?

  You know, that's a problem, if they did, they probably pretty bad doctors. I'm just saying, like if the game operation was your inspiration, you know, they're standing over the operating table with a pair of tweezers. I don't know what to do.

• 5:50Neil deGrasse Tyson?

  Or they're trying to settle malpractice suits.

• 5:53Chuck Nice?

  Right.

• 5:53Neil deGrasse Tyson?

  So that's what I know. And for me, that's the most intriguing thing.

• 5:57Chuck Nice?

  Yeah.

• 5:57Neil deGrasse Tyson?

  That you can see inside of somebody who's otherwise completely enclosed in skin.

• 6:03Neil deGrasse Tyson?

  In the same way, the 2D person is completely enclosed by a line.

• 6:07Chuck Nice?

  Right, and you can see what's inside that line.

• 6:09Neil deGrasse Tyson?

  Inside that line, so that's the best I can give them on that question.

• 6:13Chuck Nice?

  Yeah, well, that's cool.

• 6:14Neil deGrasse Tyson?

  Otherwise, yeah, I don't know where to take it.

• 6:16Chuck Nice?

  Yeah. All right, well, this is Jeff Drumsites. And Jeff Drumsites says, greetings, Dr. Tyson, Lord Nice. I recently began watching Apple TV's version of Ismael Asimov's Foundation. It is awesome.

• 6:32Neil deGrasse Tyson?

  Oh, yes, yes. That's the one where they have the hereditary rulers who are clones of each other. That's the limit of heredity.

• 6:42Chuck Nice?

  That's it.

• 6:42Neil deGrasse Tyson?

  That's it, you know.

• 6:43Chuck Nice?

  All the lineage is just a cloned line that you have. Dawn, Day, and Dusk.

• 6:49Neil deGrasse Tyson?

  Hmm.

• 6:50Chuck Nice?

  So there's.

• 6:51Neil deGrasse Tyson?

  And Day is the ruler.

• 6:51Chuck Nice?

  Day is the ruler. Dusk is the wisdom.

• 6:54Neil deGrasse Tyson?

  Wisdom, and Dawn is learning.

• 6:56Chuck Nice?

  And Dawn is learning. And they are in that constant cyclical state of replacing one another. And at a certain time, they have to be destroyed and move on. It's pretty wild. But anyway, he says this, when I was a child in the 50s, my dad's Popular Science magazine depicted the idea of a space elevator, which they have in Foundation. Trantor is the planet on which the rulers live. And the way you get to Trantor is from a space elevator. So, anyway, my question is, oh, he says, is the Trantor Star Bridge or any type of space elevator technically conceivable?

• 7:37Chuck Nice?

  Jeff Sites in Gallatin, Tennessee.

• 7:42Neil deGrasse Tyson?

  Okay.

• 7:42Chuck Nice?

  Or Gallatin, Tennessee.

• 7:44Neil deGrasse Tyson?

  The answer is yes.

• 7:45Chuck Nice?

  Yes.

• 7:45Neil deGrasse Tyson?

  Yes.

• 7:46Chuck Nice?

  Yes.

• 7:46Neil deGrasse Tyson?

  So some things to take note of.

• 7:49Chuck Nice?

  Okay.

• 7:49Neil deGrasse Tyson?

  The motivation for a space elevator is you can get to an orbit without ever firing a rocket.

• 7:55Chuck Nice?

  Yeah, there you go.

• 7:57Neil deGrasse Tyson?

  You just, all right.

• 7:58Chuck Nice?

  Just get on the elevator.

• 7:59Neil deGrasse Tyson?

  Get on the elevator.

• 8:01Chuck Nice?

  Third floor women's lingerie, and where are you going, sir? Oh, okay.

• 8:06Neil deGrasse Tyson?

  And, is that still a joke? Lingerie, that was the big. I got it from Bugs Bunny. Well, okay. The real question is, what is an entire floor doing of just lingerie? Yeah, exactly. That's, nobody's asking that question. Right. So, I have a friend who composes space music, and she created an album called Space Elevator Music. That's funny. Right. Right? On Earth, a space elevator would take you to the geosynchronous orbit. Because that's the only orbit that hovers, appears to hover over Earth. Right. Its corresponding spot on Earth. Any orbit that's closer, it will speed up ahead of the orbit of the Earth. Right. Okay?

• 8:51Neil deGrasse Tyson?

  So, to have an elevator go from a position on Earth's surface to a position in orbit, it has to go to geosynchronous. And on Earth, that's 23,000 miles. So you'd be sitting in an elevator, going 23,000 miles. Wow. If your elevator were going 1,000 miles an hour, how long would it take you to get? 23,000 hours? No, no. I mean, 1,000 miles an hour, 23 hours, that's a full day. It's still a full day. It took you one day to get, and we, we already get to space quicker than that. I know, that's right. Okay, so, the idea was, getting to space must be so hard with all these rocket engines and things, that we need another way. And, but, access to space now is routine, and the price continues to drop.

• 9:36Neil deGrasse Tyson?

  Especially because of innovations in SpaceX. Elon Musk, and it was a big mission statement of his with regard to SpaceX. You hardly hear talk of a space elevator. Elevator anymore. Right. It was a solution to a non-problem. And, you know what fuel we're using? Hydrogen and oxygen. Right. There's some solid rocket boosters, but the main tank is hydrogen, twice as big as the oxygen tank. You, it is liquefied. You put them together, they will combine in H2 and O. Okay. So the exhaust is what? Drinkable.

• 10:16Neil deGrasse Tyson?

  Yeah, the oxygen's just water, but it's highly exothermic. So, Space Odyssey is a cool technological achievement, but I don't see it-

• 10:24Chuck Nice?

  Highly impractical.

• 10:25Neil deGrasse Tyson?

  I don't see it happening.

• 10:27Chuck Nice?

  Alright, well, there you go. That's, uh, but also though, that series is, it starts off boring as hell, but then it really gets great, so.

• 10:52Speaker 02

  Hello, I'm Thinky Baroque Allen, and I support StarTalk on Patreon. This is StarTalk with Nailed Grass Tyson.

• 11:11Chuck Nice?

  Alright, this is Raphael who says, "Hello Raphael Vigod, Vigod, in Toronto, Ontario. If a super intelligent extraterrestrial offered to grant you the answer to one specific question, what would you ask?" Now, don't think too long because you have to give your immediate response. And we're only here for a few more minutes before their next interstellar train leaves.

• 11:42Neil deGrasse Tyson?

  Okay. There's a question I have every night.

• 11:45Chuck Nice?

  Alright.

• 11:46Neil deGrasse Tyson?

  Is the human brain sufficiently smart to figure out the entire universe?

• 11:52Chuck Nice?

  Wow.

• 11:54Neil deGrasse Tyson?

  That's a question I want to answer, because if it's not, then I'll buffer my expectations.

• 11:59Chuck Nice?

  Right.

• 11:59Neil deGrasse Tyson?

  But if it is, then onward we march.

• 12:03Chuck Nice?

  We can go from there.

• 12:03Neil deGrasse Tyson?

  Right.

• 12:04Chuck Nice?

  The whole, the universe is your oyster-

• 12:07Neil deGrasse Tyson?

  Right.

• 12:07Chuck Nice?

  -at that point. That's a really interesting question, because basically, are we too stupid?

• 12:14Neil deGrasse Tyson?

  Yeah, that's, I ask that every night.

• 12:15Chuck Nice?

  Like, we might just be, like, the whole quantum thing, and we're like, "Quantum, quantum, quantum." Like, maybe we're just dumb.

• 12:23Neil deGrasse Tyson?

  And it wouldn't be mysterious if we weren't so dumb.

• 12:26Chuck Nice?

  Right.

• 12:27Neil deGrasse Tyson?

  But yeah, it's obvious.

• 12:28Chuck Nice?

  Yeah.

• 12:28Neil deGrasse Tyson?

  For these reasons.

• 12:29Chuck Nice?

  Wow.

• 12:30Neil deGrasse Tyson?

  We can't even understand the reasons. So, yeah. So, I want to know. Inquiring minds want to know.

• 12:36Chuck Nice?

  It's a good question. I mean, I like it. Me? Uh, I would like to know, are there cheaper eggs, uh, somewhere in the universe than, uh, where I buy mine right now? Because they are hugely expensive.

• 12:51Neil deGrasse Tyson?

  I...

• 12:54Neil deGrasse Tyson?

  That's, that's really? That's your question?

• 12:59Neil deGrasse Tyson?

  My son, you can ask any question in the universe.

• 13:02Chuck Nice?

  Right.

• 13:05Neil deGrasse Tyson?

  I need some cheaper eggs.

• 13:06Chuck Nice?

  Yeah, no. Uh, what would I ask if I really wanted to know anything? Um, mine would be, what happened before the Big Bang?

• 13:16Neil deGrasse Tyson?

  Really?

• 13:17Chuck Nice?

  Yeah.

• 13:17Neil deGrasse Tyson?

  Okay.

• 13:18Chuck Nice?

  Like, and I don't mean what happened, I mean like, because we know what happened before the Big Bang. Who, you know, the Big Bang happened. So, what, what caused it to happen? What was there before? Give me, give me the lay of land before the Big Bang. You know? That'd be kind of cool to know.

• 13:35Neil deGrasse Tyson?

  Uh-huh. It's an origins problem.

• 13:36Chuck Nice?

  An origins.

• 13:37Neil deGrasse Tyson?

  Yeah, and origins questions are always the most challenging in science. Because you don't have other examples to compare it with. And until you do, you're kind of making stuff up.

• 13:46Chuck Nice?

  Exactly.

• 13:46Neil deGrasse Tyson?

  Right. I mean, was the origin of the Earth? No one knew until we saw planetary systems getting formed.

• 13:51Chuck Nice?

  Right.

• 13:51Neil deGrasse Tyson?

  Then we'd say, oh, it takes this long, that timeframe, this distance from the host star. You can formulate questions that have value.

• 14:00Chuck Nice?

  Yeah. But it'd be kind of cool if the aliens were, or the terrestrials were just, extraterrestrials were just like, yeah, you know, yeah, this, your, your universe is just one of 15 million that we've been to thus far. You know? And before you're, this is what happened. Two other universes got together after a night of drinking and bang, your, your universe was born! So, anyway.

• 14:25Neil deGrasse Tyson?

  Can't believe you included alcohol reference to that.

• 14:29Chuck Nice?

  This is Marcus, uh, Munslinger. And Marcus Munslinger says, hello from Germany! Or should I say, no, I'm not going to do it. I'm not going to do it. Uh, did you ever think? Uh, in my, in my accent pronounced sink about the alien in alien not needing any digestive organs since its blood is acid. So all human flesh it eats is directly dissolved into molecules. So the alien doesn't need to produce poop since it can use 100% of its food. Or did you ever see the alien take a poop?

• 15:16Chuck Nice?

  Love yourself.

• 15:17Neil deGrasse Tyson?

  Who knows about digestive tracts? I mean, we, we played with Superman's digestive tract and he was an alien.

• 15:24Chuck Nice?

  Yes.

• 15:24Neil deGrasse Tyson?

  Right.

• 15:25Chuck Nice?

  That's right.

• 15:25Neil deGrasse Tyson?

  We solved that one, I think.

• 15:26Chuck Nice?

  Yes, we did.

• 15:30Neil deGrasse Tyson?

  He has a super digestive tract.

• 15:31Chuck Nice?

  He has a super digestive tract.

• 15:32Neil deGrasse Tyson?

  That means.

• 15:33Chuck Nice?

  And everything about it is super.

• 15:34Neil deGrasse Tyson?

  Including the gaseous effluences.

• 15:36Chuck Nice?

  That's right.

• 15:37Neil deGrasse Tyson?

  Right. A plant-based alien, however, wouldn't have any such waste products where its waste product would be oxygen. That's pretty good.

• 15:45Chuck Nice?

  Right.

• 15:46Neil deGrasse Tyson?

  Right.

• 15:46Chuck Nice?

  Right.

• 15:46Neil deGrasse Tyson?

  Right, right. So I don't, you know, I'm cool with it.

• 15:51Chuck Nice?

  Yeah, yeah, it doesn't make a difference.

• 15:53Neil deGrasse Tyson?

  Right, right.

• 15:54Chuck Nice?

  A poopless alien is totally fine.

• 15:56Neil deGrasse Tyson?

  That's right.

• 15:57Chuck Nice?

  You know, I mean, there's nothing wrong with a poopless alien.

• 16:02Neil deGrasse Tyson?

  But then they have to rewrite that, that book, that kid's book.

• 16:04Chuck Nice?

  Which one?

• 16:05Neil deGrasse Tyson?

  Everybody poops.

• 16:06Chuck Nice?

  Everybody poops.

• 16:07Neil deGrasse Tyson?

  That was originally in Italian. Did you know that?

• 16:09Chuck Nice?

  I did not.

• 16:09Neil deGrasse Tyson?

  Yeah, yeah.

• 16:13Chuck Nice?

  That's funny.

• 16:15Neil deGrasse Tyson?

  Speaking of Italian, this is an old, this is an old bad dad joke.

• 16:17Chuck Nice?

  Go ahead.

• 16:18Neil deGrasse Tyson?

  What Italians call suppositories?

• 16:21Chuck Nice?

  No, I don't know.

• 16:23Neil deGrasse Tyson?

  Interuendo.

• 16:24Chuck Nice?

  Oh, no. No, please. No.

• 16:31Neil deGrasse Tyson?

  You know that's good.

• 16:32Chuck Nice?

  Oh, no.

• 16:32Neil deGrasse Tyson?

  You know it's good.

• 16:34Chuck Nice?

  Oh, man.

• 16:40Chuck Nice?

  All right, here we go. This is Matthew Landruth who says, greetings, StarTalk. My name is Matt, a globe trekking teacher who has lived and taught around the world.

• 16:51Neil deGrasse Tyson?

  Teacher in the house.

• 16:52Chuck Nice?

  There you go. Through these experiences, I have seen how much learning depends on human connection. Dr. Tyson is a fellow teacher and science communicator. You know how ideas ignite in others. Science fiction imagines AI tutors or digital replicas guiding future generations. If an AI could replicate a teacher's knowledge, style, and personality, would that truly be teaching? Or is the human connection scientifically essential for learning?

• 17:22Neil deGrasse Tyson?

  I love that. So, a couple of things. If you are teaching today with methods, tools, and tactics, and then I clone that, I'm not given any reason to think that your clone would not be as effective as you are in those situations.

• 17:38Chuck Nice?

  Right.

• 17:39Neil deGrasse Tyson?

  However,

• 17:41Neil deGrasse Tyson?

  you have a life experience, a training, where if someone whose profile doesn't fit that of other students, you will readjust and repackage what you know works so that you have a new pathway to reach the intellectual curiosity of that student. I don't know that AI can do that just now.

• 18:05Chuck Nice?

  Right.

• 18:06Neil deGrasse Tyson?

  AI can, you know, ape your style. It can, you know, dig up some content.

• 18:15Chuck Nice?

  But it can't intuit something different that might be happening in a student and then make an adjustment.

• 18:21Neil deGrasse Tyson?

  And make an adjustment, especially if students change, or they mature, or they regress.

• 18:26Chuck Nice?

  Right.

• 18:27Neil deGrasse Tyson?

  Right. So, I think that frontier, at least from my foreseeable future, that is the future that I can foresee, is, remains in the realm of the inventive creative teacher.

• 18:40Chuck Nice?

  Interesting.

• 18:41Neil deGrasse Tyson?

  Yeah.

• 18:42Chuck Nice?

  Yeah, very cool, very cool. The human condition is still a very important part of teaching.

• 18:48Neil deGrasse Tyson?

  No, no, it's the ever-changing human condition.

• 18:50Chuck Nice?

  Or the ever-changing, yes.

• 18:51Neil deGrasse Tyson?

  Yeah, because otherwise I can memorize everything in that moment.

• 18:54Chuck Nice?

  Right.

• 18:55Neil deGrasse Tyson?

  And then that's watching it go forward in time and be nimble enough to navigate that. That's the real test.

• 19:01Chuck Nice?

  There you go. All right, this is DJ Sype. He says, "This is DJ from Maine. I've been curious about the properties of spacetime and gravity. We know that gravity is the result of objects with mass bending spacetime. To me, this implies that spacetime is naturally flat, but doesn't explain why. Is there some force or property of spacetime that acts to restore its natural flat state once an object and its gravitational field move away? Perhaps some form of gravitational entropy?"

• 19:44Neil deGrasse Tyson?

  Ooh, I like that idea.

• 19:46Chuck Nice?

  The idea of gravitational entropy.

• 19:48Neil deGrasse Tyson?

  Oh, yeah, yeah.

• 19:49Chuck Nice?

  So he's looking at this whole rubber sheet type.

• 19:52Neil deGrasse Tyson?

  Yeah, yeah, so, I mean, all we can say is, by the way, it's not just matter that will bend space, it's energy as well, because matter and energy are equivalent.

• 19:58Chuck Nice?

  That's right.

• 19:59Neil deGrasse Tyson?

  Through equals mc squared.

• 20:00Chuck Nice?

  Nice.

• 20:01Neil deGrasse Tyson?

  So just be more complete, addressing it that way. So, since the curvature of space and time is the manifestation of matter and energy, if you remove the matter and energy, there's no reason for the spacetime to be curved at all. I'm given no reason to think that space would have any shape other than flat after you remove the items that would curve it.

• 20:28Chuck Nice?

  Right.

• 20:29Neil deGrasse Tyson?

  Keep in mind, however, the expanding or contracting universe itself has a shape unrelated to the gravity of objects it contains.

• 20:38Chuck Nice?

  Right.

• 20:39Neil deGrasse Tyson?

  And this is why we talked about, is an open universe, a closed universe, or a flat universe? And those are large-scale properties that are not related to just one galaxy or another.

• 20:50Chuck Nice?

  There you go.

• 20:51Neil deGrasse Tyson?

  Mm-hmm.

• 20:51Chuck Nice?

  Very cool, man.

• 20:52Neil deGrasse Tyson?

  That's a great question, DJ.

• 20:54Chuck Nice?

  I know. These people are thinking, I love it. This is Keith Johnson, uh, from NorCal. And Keith says, uh, can we think of a universal now based on the point of view of an observer? In other words, my now, can we analyze a particular star in the night sky and determine its probable lifespan? And then say that this particular star does not, in all probability, exist anymore in my now. Its ghost is seen as a shadow of light arriving billions of light years after its demise.

• 21:36Neil deGrasse Tyson?

  So what's the question in there?

• 21:38Chuck Nice?

  So I guess he's saying, is that the case? Like when we look up, are we seeing stuff that's not there?

• 21:42Neil deGrasse Tyson?

  We see things not as they are, but as they once were.

• 21:45Chuck Nice?

  Hmm.

• 21:46Neil deGrasse Tyson?

  We're not worried if they're no longer there because that's not a real thing we can interact with. We're interacting with a light that is currently reaching us. And when that light was emitted, it was alive, whatever it was.

• 21:59Chuck Nice?

  Right.

• 22:00Neil deGrasse Tyson?

  So...

• 22:01Chuck Nice?

  So we're looking back in time, but we're looking at that time.

• 22:03Neil deGrasse Tyson?

  At that time.

• 22:04Chuck Nice?

  So it doesn't make a difference?

• 22:05Neil deGrasse Tyson?

  No.

• 22:05Chuck Nice?

  Because we're looking at that time.

• 22:06Neil deGrasse Tyson?

  Correct, correct. It doesn't make a difference.

• 22:08Chuck Nice?

  Right.

• 22:09Neil deGrasse Tyson?

  So might as well speak of it in the present.

• 22:12Chuck Nice?

  Right.

• 22:13Neil deGrasse Tyson?

  The star exploded last night. No, it was 1,700 years ago. But what do you gain by that, right? Other than like a nerdy kid saying, you got it wrong. It's not really in the now. So the fun part would be find a galaxy 33 light years away. Uh, sorry. Find a galaxy 33 million light years away.

• 22:32Chuck Nice?

  Okay.

• 22:35Neil deGrasse Tyson?

  And then if they all held up mirrors and you looked at those mirrors, you would see the dinosaurs going extinct.

• 22:44Chuck Nice?

  Oh wow.

• 22:47Neil deGrasse Tyson?

  Because it's thirty-three light years, years there.

• 22:49Chuck Nice?

  And thirty-three light years back.

• 22:51Neil deGrasse Tyson?

  Sixty-six years.

• 22:52Chuck Nice?

  So.

• 22:53Neil deGrasse Tyson?

  Into the past.

• 22:54Chuck Nice?

  Look at that.

• 22:54Neil deGrasse Tyson?

  Yeah, yeah. So, um, yeah, it's fun to think that way.

• 22:59Chuck Nice?

  Right.

• 23:00Neil deGrasse Tyson?

  You know, our speeds are not high enough to generate significant relativistic, um, phenomena.

• 23:08Chuck Nice?

  Got you.

• 23:08Neil deGrasse Tyson?

  Yeah.

• 23:09Chuck Nice?

  All right. Well, there you have it. Still a fun question, though. Thanks. Thanks for the fun question, buddy. All right. Um, that was Keith and this is Anthony Calomani. Calomani.

• 23:21Neil deGrasse Tyson?

  Tony Calomani.

• 23:22Chuck Nice?

  Tony Calomani.

• 23:24Neil deGrasse Tyson?

  Everyone's Italian voice does not come from Brooklyn, okay?

• 23:26Chuck Nice?

  Ah, and they do in my world.

• 23:32Chuck Nice?

  All right. This is, uh, uh, this is Anthony and he says, greetings from Seattle. Dr. Tyson, Lord Nice. My eleven-year-old son and I were discussing the pitfalls of fictional time travel within the space-time continuing.

• 23:46Neil deGrasse Tyson?

  Okay.

• 23:46Chuck Nice?

  Understanding that you have pointed out on many occasions that one would have to calculate not only the space-time location on the target on Earth as it rotates on its axis revolves around the sun and the trajectory of our solar system moving through space, but also as our galaxy moves through the universe. Well, he covered it all. Look at you, man.

• 24:06Neil deGrasse Tyson?

  Well.

• 24:07Chuck Nice?

  This was way to go. Our question is, would one have to know the center or origin point of the universe to guarantee an accurate space-time coordinate? Or would relative distances be enough, even if the universe is, even if the universe isn't expanding in uniform fashion? So he's taking into account the expansion of the universe in the time travel equation as well.

• 24:33Neil deGrasse Tyson?

  Yeah, but I don't, I'm trying to figure out what he's getting at. So.

• 24:37Chuck Nice?

  So he's saying, I'm gonna go and come back. That's what he left out. So I gotta go back and then I gotta come back to my time. So.

• 24:47Neil deGrasse Tyson?

  Is he going into the past?

• 24:48Chuck Nice?

  Into the past. So my coordinate, okay, what am I gonna need? Can I, can I accurately predict with not only rotation of the earth, but the solar system and the galaxy moving and also the expansion of the universe? Can I accurately predict the point where I gotta go back and be back in time? I traveled at the speed of light and faster than the speed of light, went back in time. And then come back to that same point where I left. Can I do that?

• 25:20Neil deGrasse Tyson?

  Rich Gott, I think, would say you can.

• 25:22Chuck Nice?

  Okay.

• 25:23Neil deGrasse Tyson?

  Using sort of mathematical trajectories in the vicinity of black holes. I have to trust him on that because I can't duplicate those calculations.

• 25:31Chuck Nice?

  Okay.

• 25:32Neil deGrasse Tyson?

  He's, he's studied this stuff, like professionally.

• 25:35Chuck Nice?

  Okay.

• 25:36Neil deGrasse Tyson?

  So in fact, he wrote a book, Time Travel in Einstein's Universe.

• 25:39Chuck Nice?

  All right.

• 25:40Neil deGrasse Tyson?

  So in principle, yes, but is there a no disruption conjecture? Where you're not allowed to prevent your parents from meeting, thereby preventing you from being born, thereby preventing you from coming back to try to rectify things? So.

• 26:00Chuck Nice?

  Hey Marvin.

• 26:05Chuck Nice?

  I think I got that sound you were looking for Marvin. No, it's me, your cousin.

• 26:13Neil deGrasse Tyson?

  So Marvin?

• 26:14Chuck Nice?

  No, that's right. He was calling Chuck Berry. He's Marvin.

• 26:17Neil deGrasse Tyson?

  He's Marvin.

• 26:17Chuck Nice?

  It's me, your cousin Marvin.

• 26:19Neil deGrasse Tyson?

  Chuck, it's me, your cousin Chuck. Yeah, yeah, yeah, Chuck Berry, Marvin Berry.

• 26:23Chuck Nice?

  Marvin Berry.

• 26:24Neil deGrasse Tyson?

  Yeah, from Back to the Future.

• 26:26Chuck Nice?

  Right.

• 26:26Neil deGrasse Tyson?

  Living under a rock. Uh, so. And by the way, I think we talked about this on another episode about gin particles.

• 26:36Chuck Nice?

  Yes, we did, which I love.

• 26:38Neil deGrasse Tyson?

  So that's a gin song.

• 26:39Chuck Nice?

  No, we did a, um, we didn't explain it.

• 26:41Neil deGrasse Tyson?

  Explain it. So that'd be a gin song.

• 26:43Chuck Nice?

  Gin song. That would be a gin song.

• 26:44Neil deGrasse Tyson?

  A gin song.

• 26:45Chuck Nice?

  Because it didn't exist until Marvin Berry put the phone out and let Chuck Berry hear Johnny B. Good.

• 26:55Neil deGrasse Tyson?

  The song that he wrote.

• 26:57Chuck Nice?

  He wrote.

• 26:58Neil deGrasse Tyson?

  He wrote, and then.

• 27:01Neil deGrasse Tyson?

  Marty picks it up later.

• 27:02Chuck Nice?

  Right.

• 27:03Neil deGrasse Tyson?

  Right.

• 27:03Chuck Nice?

  So Marty gets it in the future, but Chuck gets it in the past.

• 27:08Neil deGrasse Tyson?

  Right. And so that song was never actually written.

• 27:13Chuck Nice?

  Never actually written.

• 27:14Neil deGrasse Tyson?

  Right. It just lives in a time loop.

• 27:16Chuck Nice?

  Yeah. I love that whole gin particle thing, man. That's gin, the gin stuff.

• 27:21Neil deGrasse Tyson?

  It's a gin song.

• 27:22Chuck Nice?

  Yeah.

• 27:22Neil deGrasse Tyson?

  So.

• 27:23Chuck Nice?

  What was the other movie we did that?

• 27:25Neil deGrasse Tyson?

  Oh, it was Somewhere in Time.

• 27:26Chuck Nice?

  A woman with a.

• 27:27Neil deGrasse Tyson?

  Yeah.

• 27:28Chuck Nice?

  With a piece of jewelry or something.

• 27:29Neil deGrasse Tyson?

  Somewhere in Time.

• 27:30Chuck Nice?

  Somewhere in Time, that's the name of it?

• 27:31Neil deGrasse Tyson?

  Yeah.

• 27:31Chuck Nice?

  Okay, cool.

• 27:32Neil deGrasse Tyson?

  It's a, it's a, it's a romantic story.

• 27:35Chuck Nice?

  Oh, that's why I don't like it. Okay. So anyway.

• 27:38Neil deGrasse Tyson?

  I was gonna say rom-com, but it's not a com.

• 27:39Chuck Nice?

  Oh, okay.

• 27:40Neil deGrasse Tyson?

  It's just a rom.

• 27:40Chuck Nice?

  Just a rom.

• 27:44Neil deGrasse Tyson?

  But it had, it had Christopher Reeve in it.

• 27:46Chuck Nice?

  Oh, okay.

• 27:46Neil deGrasse Tyson?

  Superman.

• 27:47Chuck Nice?

  All right.

• 27:48Neil deGrasse Tyson?

  After Superman, after he did it.

• 27:49Chuck Nice?

  All right, wow.

• 27:50Neil deGrasse Tyson?

  But he's a handsome guy, you know?

• 27:52Chuck Nice?

  Yeah, I mean, listen, they can't all be winners.

• 27:56Chuck Nice?

  He did Superman.

• 28:02Chuck Nice?

  So anyway, Rich Gott says that this can happen.

• 28:05Neil deGrasse Tyson?

  Yeah, yeah. So I don't, I can't follow his math.

• 28:09Chuck Nice?

  Okay.

• 28:09Neil deGrasse Tyson?

  Uh, but, I mean, I follow it, but I couldn't derive it. Right. I mean, he's, he's in it.

• 28:14Chuck Nice?

  You gotta repeat, right.

• 28:15Neil deGrasse Tyson?

  Yeah, he does it. He does it.

• 28:16Chuck Nice?

  He does it.

• 28:17Neil deGrasse Tyson?

  He figures it out. So I just recommend that book of his.

• 28:19Chuck Nice?

  Okay.

• 28:20Neil deGrasse Tyson?

  Time Traveler and Einstein's Universe.

• 28:21Chuck Nice?

  Yeah.

• 28:22Neil deGrasse Tyson?

  Mm-hmm.

• 28:22Chuck Nice?

  Very cool. Great question, and I just like the fact that you're talking to your 11-year-old about the universe and time travel and such specificity, which is fantastic. All right, this is Todd Chambers, who says, hello, Dr. Tyson, the Todd Chambers here from Yuba City, California.

• 28:41Neil deGrasse Tyson?

  What kind of city?

• 28:42Chuck Nice?

  Yuba.

• 28:43Neil deGrasse Tyson?

  Yuba.

• 28:44Chuck Nice?

  It's right next to Yaba Daba Doo-Ba.

• 28:47Neil deGrasse Tyson?

  Oh, what's that 1210 from Yuba? Or Yuma? What's that, the train?

• 28:50Chuck Nice?

  Uh, I don't know.

• 28:51Neil deGrasse Tyson?

  No, Yuma.

• 28:52Chuck Nice?

  Yuma.

• 28:53Neil deGrasse Tyson?

  Yuma, not Yuba.

• 28:55Chuck Nice?

  Three ten to you, Ma.

• 28:55Neil deGrasse Tyson?

  Three ten to yabba dabba doo, okay, go on.

• 28:58Chuck Nice?

  So, he says, "I'm a retired naval officer and earth science teacher."

• 29:03Neil deGrasse Tyson?

  Nice. That's a nice combo, right there.

• 29:06Chuck Nice?

  That's a great combo, yeah. He says, "Does light ever do any work?" Well, it does light work, no. Uh, he says...

• 29:17Chuck Nice?

  I'm sorry, I couldn't resist. I had to do it. He says, "Does light ever do any work?"

• 29:23Neil deGrasse Tyson?

  But it does do windows.

• 29:24Chuck Nice?

  Right. And, "What would that look like to an observer of the night sky?"

• 29:33Neil deGrasse Tyson?

  Right. So, there's something called a solar sail.

• 29:36Chuck Nice?

  Yes!

• 29:37Neil deGrasse Tyson?

  Where, you have a big, sort of Mylar, low mass, high reflective... Mylar's like what they wrap around the...

• 29:45Chuck Nice?

  The balloons.

• 29:45Neil deGrasse Tyson?

  Balloons, Mylar balloons, yeah. And I think Mylar might be what they wrap around the, um...

• 29:52Chuck Nice?

  The marathon runners.

• 29:53Neil deGrasse Tyson?

  Marathon runners. It might be some Mylar variant.

• 29:56Chuck Nice?

  Yeah.

• 29:57Neil deGrasse Tyson?

  Flexible, shiny, highly reflective, so it keeps your radiant heat in.

• 30:02Chuck Nice?

  Right.

• 30:03Neil deGrasse Tyson?

  So it can be warm without it being a blanket.

• 30:05Chuck Nice?

  Like, yeah, right.

• 30:06Neil deGrasse Tyson?

  Right? Because that's all a good blanket does, is prevent your heat from getting out.

• 30:09Chuck Nice?

  Yeah.

• 30:09Neil deGrasse Tyson?

  We did a whole explainer on that.

• 30:11Chuck Nice?

  Blankets!

• 30:12Neil deGrasse Tyson?

  On blankets, a hundred years ago.

• 30:13Chuck Nice?

  Blanket, I love you blanket.

• 30:15Neil deGrasse Tyson?

  Right. Many people think if you put a blanket on something, you'll make it warm.

• 30:18Chuck Nice?

  Right.

• 30:19Neil deGrasse Tyson?

  But no, this has actually been built by funds of membership of the Planetary Society.

• 30:25Chuck Nice?

  That's right.

• 30:25Neil deGrasse Tyson?

  A good friend of, uh, StarTalk is Bill Nye, who is the CEO of the Planetary Society. They funded, built, and launched a solar sail. And, the way it worked is, because it was a test, it was a test, um, prototype. So, it's orbiting the Earth, and if you want to see if light can do work, you open up the solar sail, angle it in ways to your advantage, and see if sunlight can press on that solar sail and increase your orbit around the Earth.

• 30:59Neil deGrasse Tyson?

  And it did. Oh. So the light is doing work. Light is doing work. Yes. Wow. Okay, and. Reflection as propulsion. Yes. That's amazing. Yes. That's amazing. Yes. Reflection as propulsion. Yes. That's awesome. And there's a, and there's something called the Breakthrough Initiative. Which is a chunk of money, some billionaires participated in this. Where it gives awards for new, new inventions that we think we need. But it just takes some innovative people to do it. Someone wanted, when are we gonna have a tricorder? Right. Just a portable thing. And then you have all the.

• 31:45Neil deGrasse Tyson?

  Okay, that's a useful thing, why not? So cool. All right, so.

• 31:50Neil deGrasse Tyson?

  So one of them is a, it's called these nano sails. These, these, these nano probes. So nano means a billionth of, so people abuse the word. Right. They just use it for anything small. Well, that's because Apple came out with the nano and that was the end of it. That was the end, yeah. Yeah, that was it. They have these nano sails, so they're like, they fit in your palm. They're like the size of a postage stamp. Attached to it is a huge Mylar sail, okay? They get deployed in a rocket launch. Then you have ground-based gigawatt lasers. Oh, that is amazing.

• 32:34Neil deGrasse Tyson?

  Beaming these things in the direction you want them to go. And that propels them forward. Correct. And, and the goal is to send these to Alpha Centauri. And you can accelerate it up to like 20% the speed of light. Yes, because like there's nothing to impede it because you're in the vacuum of space. So the laser is pushing one of the holes. And the sail is huge and the laser is powerful. That's awesome. Right, and so, and you can pack a lot on a postage stamp chip. Right. Okay, like, you know, temperature and, and, and radiation field and, and magnetic field. They can, and so that's the goal. And so let's see how good you are at math.

• 33:15Chuck Nice?

  I'm not. Let's not.

• 33:19Neil deGrasse Tyson?

  If it goes, if it reaches 20% the speed of light. And Alpha Centauri is four light years away.

• 33:26Chuck Nice?

  Okay.

• 33:26Neil deGrasse Tyson?

  How long does it take to get there?

• 33:28Chuck Nice?

  It'll take 20, wait, it's four light years away and it's at 20%. So one light year would be one year. So that's four times that, right? Now five times that.

• 33:46Neil deGrasse Tyson?

  Is that your final answer?

• 33:47Chuck Nice?

  Right. So it's 20, 20 years, right?

• 33:49Neil deGrasse Tyson?

  Okay, now I'm okay.

• 33:52Neil deGrasse Tyson?

  Yes, 20 years, yes.

• 33:53Chuck Nice?

  Now you know how this craziness works. That's how I do math.

• 33:56Neil deGrasse Tyson?

  We just exposed the wiring of your brain in that moment.

• 34:00Chuck Nice?

  I'm sorry.

• 34:02Chuck Nice?

  You see how freaking nuts it is up in there, but I come out to the right stuff. But anyway, 20 years.

• 34:08Neil deGrasse Tyson?

  Yeah, if you go one fifth the speed of light.

• 34:09Chuck Nice?

  Right.

• 34:10Neil deGrasse Tyson?

  And you're four light years, it'll be five times four is 20. So 20 years, that's within people's lifetime who are funding the thing. And so that was the goal.

• 34:18Chuck Nice?

  That's.

• 34:19Neil deGrasse Tyson?

  However, it gets there, now it's to send a signal back.

• 34:22Chuck Nice?

  Oh, well, that's crazy.

• 34:23Neil deGrasse Tyson?

  That's at the speed of light.

• 34:24Chuck Nice?

  Right.

• 34:24Neil deGrasse Tyson?

  So when do you know what it found there? After how much time?

• 34:28Chuck Nice?

  24 years.

• 34:30Neil deGrasse Tyson?

  Chuck!

• 34:31Chuck Nice?

  Yeah.

• 34:32Neil deGrasse Tyson?

  Wouldn't give you an honorary degree. Just being on the show.

• 34:36Chuck Nice?

  Yeah, I was gonna say, yes. Well, you can, you got like 30 of them up there.

• 34:41Neil deGrasse Tyson?

  No, 27.

• 34:42Chuck Nice?

  Okay, you mobiles count.

• 34:51Chuck Nice?

  All right.

• 34:52Neil deGrasse Tyson?

  Super cool, man.

• 35:16Chuck Nice?

  This is Dusty Rock Creations.

• 35:21Chuck Nice?

  And Dusty Rock Creations says hello from Quebec, Canada.

• 35:24Neil deGrasse Tyson?

  Quebec.

• 35:24Chuck Nice?

  Quebec. And he says, this is Jean-François Roch, who says, "Hear from Dusty Rock Creations."

• 35:32Neil deGrasse Tyson?

  Oh, you think?

• 35:32Chuck Nice?

  He's dropping names. He says, "Mr. Tyson Lord Nice, let's dive into some fascinating questions, if you do say so yourself."

• 35:42Neil deGrasse Tyson?

  It will be the judge of that.

• 35:43Chuck Nice?

  It will be the judge of that.

• 35:46Chuck Nice?

  He says, "Supermassive black holes at the heart of galaxies hold the key to understanding how galaxies come into being."

• 35:52Neil deGrasse Tyson?

  Maybe, yes.

• 35:53Chuck Nice?

  Maybe.

• 35:54Neil deGrasse Tyson?

  Let me tell you why it's a maybe.

• 35:56Chuck Nice?

  Okay.

• 35:56Neil deGrasse Tyson?

  Because the supermassive black hole has like, the big ones, like a billion solar masses. Give them 10 billion, but billions. We can Carl Saganify it.

• 36:08Chuck Nice?

  Billion.

• 36:09Neil deGrasse Tyson?

  Billion.

• 36:10Chuck Nice?

  Right.

• 36:11Neil deGrasse Tyson?

  So, the mass of a galaxy, however, is hundreds of billions times the mass of the sun. So, maybe the black hole nucleated some things to begin with, but the mass of the galaxy swamps the mass of the black hole. So, there's a limit to how much you're gonna credit the black hole for the whole damn, the kit and the caboodle.

• 36:36Chuck Nice?

  Gotcha.

• 36:37Neil deGrasse Tyson?

  So, continue.

• 36:38Chuck Nice?

  That's a very good point. He says, "Is it fair to say that entire galaxies will inevitably end up being swallowed by their own black holes and disappear forever?"

• 36:53Neil deGrasse Tyson?

  No.

• 36:54Chuck Nice?

  No. Yep, there you go.

• 36:57Chuck Nice?

  Thank you for being my everyday source of wonder.

• 37:00Neil deGrasse Tyson?

  Oh, thank you. I love that.

• 37:02Chuck Nice?

  Did you get my name right? I don't know.

• 37:07Neil deGrasse Tyson?

  Okay, what's the, what's the name?

• 37:08Chuck Nice?

  I don't know if I got anybody's name. I said his name was Jean Francois Rock.

• 37:14Neil deGrasse Tyson?

  R O Q U E?

• 37:16Chuck Nice?

  R O C K.

• 37:17Neil deGrasse Tyson?

  Oh, Rock?

• 37:18Chuck Nice?

  Yeah.

• 37:18Neil deGrasse Tyson?

  Rock.

• 37:18Chuck Nice?

  But Jean, G E A N dash F R A N C I O S.

• 37:24Neil deGrasse Tyson?

  Francois.

• 37:25Chuck Nice?

  Francois, right? Rock, so maybe I got it right.

• 37:28Neil deGrasse Tyson?

  Broch, I bet it is.

• 37:30Chuck Nice?

  Exactly.

• 37:30Neil deGrasse Tyson?

  Okay, you did pretty good. I'll give you a B plus on that.

• 37:32Chuck Nice?

  Yeah, I mean, I did the best I could, but no. Listen, truth is, if I mispronounce your name, I did you a favor, okay? Cause now you got an alias, okay? You got a StarTalk alias.

• 37:43Neil deGrasse Tyson?

  So, here's the thing.

• 37:46Neil deGrasse Tyson?

  A black hole is really tiny relative to the gal- They're big, they're like the size, the billion solar mass black holes are like multiples of the size of the solar system. But that's still tiny in the middle of the galaxy, okay?

• 37:59Chuck Nice?

  Right.

• 38:00Neil deGrasse Tyson?

  If it's gonna eat the galaxy, the, the matter that's orbiting it has to stop orbiting and fall straight in.

• 38:10Chuck Nice?

  Right.

• 38:10Neil deGrasse Tyson?

  And that's just not gonna happen.

• 38:11Chuck Nice?

  No, it's not.

• 38:12Neil deGrasse Tyson?

  Okay?

• 38:13Chuck Nice?

  Right.

• 38:14Neil deGrasse Tyson?

  Maybe stuff nearby, here's what'll happen, a star will come nearby and it'll, tidal forces will stretch it out and you'll get this wispy stream of gas spiraling in down to the black hole. Then it can make an accretion disk, that's what we call them. This is where, that's the holding place. This is, it's taxiing, ready to go into the black hole.

• 38:39Chuck Nice?

  Mm-hmm.

• 38:40Neil deGrasse Tyson?

  As it's falling towards the black hole,

• 38:43Chuck Nice?

  Mm-hmm.

• 38:43Neil deGrasse Tyson?

  It's slowing down from the friction of all the other material there and that energy has to go somewhere and it goes to heating the accretion disk.

• 38:51Chuck Nice?

  Okay.

• 38:51Neil deGrasse Tyson?

  So hot. Millions of degrees that it radiates ultraviolet and X-ray light. So the X-ray telescopes were the first telescopes to discover black holes. Because we did the math of what that should look like.

• 39:04Chuck Nice?

  Right.

• 39:04Neil deGrasse Tyson?

  Point is, you only get these accretion discs from things that are very close.

• 39:07Chuck Nice?

  Right.

• 39:08Neil deGrasse Tyson?

  That can be, that, that trip on the, on the matter, that'll slow them down. Anybody else doesn't even care that there's a black hole.

• 39:15Chuck Nice?

  Right.

• 39:16Neil deGrasse Tyson?

  There.

• 39:16Chuck Nice?

  Right. Yeah, it's like when you explained that even if our sun became a black hole.

• 39:22Neil deGrasse Tyson?

  Correct.

• 39:23Chuck Nice?

  We would still just be orbiting a black hole now that is our sun.

• 39:27Neil deGrasse Tyson?

  It doesn't have extra gravity.

• 39:28Chuck Nice?

  It doesn't have, right.

• 39:29Neil deGrasse Tyson?

  Correct.

• 39:29Chuck Nice?

  Because the gravity is due to the mass and the mass does not change.

• 39:33Neil deGrasse Tyson?

  Yeah, if you turn our, it, it, it wouldn't happen naturally, but if you

• 39:36Chuck Nice?

  Right.

• 39:37Neil deGrasse Tyson?

  magic hands to do it.

• 39:38Chuck Nice?

  Right.

• 39:38Neil deGrasse Tyson?

  Uh, yeah, it would just be a black hole and if it's the same mass, we're just still orbiting around.

• 39:43Chuck Nice?

  Orbiting around that.

• 39:43Neil deGrasse Tyson?

  Mm-hmm.

• 39:44Chuck Nice?

  So now.

• 39:44Neil deGrasse Tyson?

  We freeze to death.

• 39:45Chuck Nice?

  I got, yeah, we'll freeze to death. Um, but Jean Francois actually has made me have a question.

• 39:53Neil deGrasse Tyson?

  Francois.

• 39:54Chuck Nice?

  So when two galaxies collide.

• 39:58Neil deGrasse Tyson?

  Mm-hmm.

• 39:59Chuck Nice?

  Do the black holes then actually fall into one to another and become one giant black hole around that galaxy?

• 40:08Neil deGrasse Tyson?

  They will very likely eventually find each other.

• 40:11Chuck Nice?

  Ah.

• 40:12Neil deGrasse Tyson?

  Okay, they will probably, you look at the dynamics of colliding galaxies. Galaxies are mostly empty, by the way.

• 40:19Chuck Nice?

  Right.

• 40:20Neil deGrasse Tyson?

  I had in one of my Merlin, one of the questions in the Merlin book where what are the chances of two stars colliding? Just in the galaxy?

• 40:27Chuck Nice?

  Mm-hmm.

• 40:28Neil deGrasse Tyson?

  And I said, if there were four bumblebees in the continental United States, the chances are greater that two of them would accidentally bump into each other than two stars collide in our galaxy.

• 40:43Chuck Nice?

  Damn.

• 40:45Neil deGrasse Tyson?

  Did my brother do two bumblebees that hit each other, they had like, you know.

• 40:49Chuck Nice?

  Oh, your little bumblebee hickies.

• 40:51Neil deGrasse Tyson?

  But no, just, you know, bumblebees stunned.

• 40:53Chuck Nice?

  Right.

• 40:54Neil deGrasse Tyson?

  Clouds over their heads. So it's empty. So when the star, when the galaxies collide, they will pass through one another.

• 41:01Chuck Nice?

  Right.

• 41:02Neil deGrasse Tyson?

  It'll be this cosmic ballet, choreographed by the forces of gravity. And it'll pulse like that as they pass through each other, come back, collide again. And they keep doing this until it settles down. Because there's energy dissipated each time that happens. And the settling down puts the heavy stuff in the middle, the heavy, slow-moving stuff in the middle, and the faster, lighter stuff in the outer region. That's when the system is settling.

• 41:31Chuck Nice?

  Right.

• 41:32Neil deGrasse Tyson?

  And the black holes, they're the heavy thing in the middle.

• 41:34Chuck Nice?

  Of course.

• 41:35Neil deGrasse Tyson?

  So they'll find each other in the middle, they'll, they'll merge, and you'll get a black hole twice the size you had before.

• 41:41Chuck Nice?

  Wow.

• 41:42Neil deGrasse Tyson?

  Yeah. We got time for one more question.

• 41:43Chuck Nice?

  Oh.

• 41:44Neil deGrasse Tyson?

  This is a very grab bag. I love it.

• 41:46Chuck Nice?

  This was a great one. Yeah. This is Patrick. He says, Dr. Tyson, Lord Nice, just another science nerd here from Texas.

• 41:52Neil deGrasse Tyson?

  Love him.

• 41:53Chuck Nice?

  What if spacetime itself is a super solid lattice? Where defects create natural time loops that erase paradoxes? And the so-called mystery echoes LIGO is hearing are actually the fingerprints of that lattice, meaning we've already stumbled onto evidence of a new state of reality and missed it because we were looking through the wrong lens.

• 42:16Neil deGrasse Tyson?

  Ooh.

• 42:18Chuck Nice?

  Wow, Patrick.

• 42:20Neil deGrasse Tyson?

  I like that. What I like about it is he's thinking of space, the fabric of spacetime, as a medium.

• 42:29Chuck Nice?

  You're right.

• 42:30Neil deGrasse Tyson?

  Okay?

• 42:31Chuck Nice?

  Mm-hmm.

• 42:31Neil deGrasse Tyson?

  And if you think of it as a medium, we sort of already do, but we think of it as sort of fabric rather. Lattice is a stronger entity than just fabric.

• 42:41Chuck Nice?

  Right.

• 42:42Neil deGrasse Tyson?

  Right? If it's a lattice, then you can think about like crystal lattices.

• 42:46Chuck Nice?

  Right.

• 42:47Neil deGrasse Tyson?

  In crystal lattices, things happen within them, you know? You can have like, light behaves in certain ways in one direction versus another. Sound goes in different ways because the lattice forces energy to pass through it differently depending on the direction that the energy goes through it. And so we would have to propose a series of experiments to check.

• 43:11Neil deGrasse Tyson?

  Whether phenomenon that unfolds within the lattice is different when viewed at different angles. That would be, I think, based on my understanding of the geology of a lattice, you know, the rock, rock science. Right. Of lattice, of what a crystal would be. So, I think he's saying, without saying it, that maybe the entire fabric of the universe is a crystal. Hmm. I think he's saying that without saying it. Wow. And, we invented in our lifetime, liquid crystal. That's right. That's what your, the wristwatches used to have. I mean, not your computer, your, yeah, all your screens. Yeah, liquid crystals. TVs.

• 43:55Neil deGrasse Tyson?

  So, this, hmm, yeah, I don't have a good answer to that, other than that's intriguing. Yeah. Yeah. The universe is a television. There you go. Back in the day, nobody had, no, the, the, L, LEDs. LEDs now, yeah. Light emitting diodes, which are better. Liquid crystal displays, right, right. No more LCD TVs. Right. Yeah, so anyhow, I like it. It's a great, it's a great thought. Very creative. Very creative. Maybe you can develop it further. Yeah, I doubt that. Why, why? I'm just, I'm just hatin'. If you came up with that question. Yeah, no, of course, no, no, I think it's brilliant what he's came up with. Then we're gonna find out he's a ten-year-old kid. Now, that would be impressive. Yeah. Nah, it's very cool, man. All right.

• 44:40Neil deGrasse Tyson?

  So we gotta end it there. Oh, man, that was a good one. These people, you people, you're amazing. Chuck, always good to have you, man. Always a pleasure. Another installment of StarTalk Cosmic Queries, Grab Bag Edition. Neil deGrasse Tyson wishing you to keep looking up.