Cosmic Queries – Negative Gravity

What happens to gravity when matter converts to energy? Neil deGrasse Tyson and co-host Paul Mecurio dive into fan questions about the speed of light, time machine mistakes, and what Neil would do if he were an alien.

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

• 0:00Neil deGrasse Tyson?

  Paul, people loving them some relativity.

• 0:02Paul Mecurio?

  Oh.

• 0:02Neil deGrasse Tyson?

  Man.

• 0:03Paul Mecurio?

  We got general, we got special.

• 0:05Neil deGrasse Tyson?

  Man, with time dilation and space and curvature, it never stops.

• 0:09Paul Mecurio?

  You know, I was feeling a little time dilation, like a little shfilkus, but I'm feeling all right now.

• 0:14Neil deGrasse Tyson?

  All that and more coming up on StarTalk.

• 0:19Neil deGrasse Tyson?

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

• 0:28Neil deGrasse Tyson?

  StarTalk begins right now.

• 0:32Neil deGrasse Tyson?

  This is StarTalk. Neil deGrasse Tyson here, your personal astrophysicist. We're gonna do cosmic queries today, because today I have Paul Mecurio. Paul.

• 0:43Paul Mecurio?

  What's up, my friend?

• 0:44Neil deGrasse Tyson?

  Welcome back to StarTalk.

• 0:45Paul Mecurio?

  Great to see you.

• 0:46Neil deGrasse Tyson?

  What'd you do with Chuck? What'd you do?

• 0:48Paul Mecurio?

  You know, he's in a bag somewhere.

• 0:52Paul Mecurio?

  Last time I checked, he was breathing.

• 0:53Neil deGrasse Tyson?

  He was still breathing.

• 0:56Neil deGrasse Tyson?

  So how you been, man?

• 0:57Paul Mecurio?

  I'm good.

• 0:57Neil deGrasse Tyson?

  I miss you. I miss you still doing the Late Show.

• 1:00Paul Mecurio?

  Doing the Late Show with Stephen Colbert, just another appearance on that. I've been touring with my Broadway show Permission to Speak, directed by Frank Oz.

• 1:07Neil deGrasse Tyson?

  Frank Oz, he's the voice of Yoda.

• 1:09Paul Mecurio?

  He's Yoda. He's a mensch, as they say. He's a great, he's just a brilliant artist.

• 1:12Neil deGrasse Tyson?

  We love him.

• 1:13Paul Mecurio?

  Yeah. And.

• 1:13Neil deGrasse Tyson?

  He's been on our show. You can find him in our archives.

• 1:15Paul Mecurio?

  He's amazing, and he's just.

• 1:18Neil deGrasse Tyson?

  And you'll see all, how the breadth and depth of all that he is.

• 1:21Paul Mecurio?

  Oh, the Muppet creator with Jim Henson of the Muppet. He created Miss Piggy and Fozzie Bear, directed everybody from Marlon Brando to Robert De Niro to me. I don't know what that's about. He's really a step down.

• 1:33Neil deGrasse Tyson?

  There it is.

• 1:34Paul Mecurio?

  I think he's living in his car by the river.

• 1:36Neil deGrasse Tyson?

  We love, so this is a grab bag.

• 1:38Paul Mecurio?

  This is a grab bag. We love these.

• 1:40Neil deGrasse Tyson?

  I haven't seen them before.

• 1:41Paul Mecurio?

  Nope.

• 1:41Neil deGrasse Tyson?

  If I don't know the answer, I'll just say, I don't know.

• 1:43Paul Mecurio?

  Yeah, you know, you always know the answers.

• 1:45Neil deGrasse Tyson?

  No.

• 1:45Paul Mecurio?

  Okay, here we go. Eric Krajcudoty, Dr. Tyson and Duke Mecurio. Wow, never been called a duke before.

• 1:53Neil deGrasse Tyson?

  Oh, cuz, oh, cuz Chuck is called Lord.

• 1:57Paul Mecurio?

  Oh.

• 1:57Neil deGrasse Tyson?

  Lord Nice.

• 1:58Paul Mecurio?

  Oh, okay.

• 1:59Neil deGrasse Tyson?

  Okay, whatever, he's got a title.

• 2:00Paul Mecurio?

  I'm a duke now. There we go. Oh, I hope that matters at home with my wife.

• 2:04Neil deGrasse Tyson?

  But are you Duke of Earl?

• 2:08Neil deGrasse Tyson?

  What do you?

• 2:09Paul Mecurio?

  Do, do, do, do.

• 2:10Neil deGrasse Tyson?

  Duke of Earl.

• 2:11Paul Mecurio?

  Alright.

• 2:11Neil deGrasse Tyson?

  They got lower. Do, do.

• 2:13Paul Mecurio?

  Yo, you can do that. I can do do, do, do.

• 2:16Neil deGrasse Tyson?

  Duke of Earl.

• 2:17Paul Mecurio?

  We're gonna just do this for thirty minutes.

• 2:19Neil deGrasse Tyson?

  Duke of Earl. Then you gotta come in high. Give me some falsetto.

• 2:22Paul Mecurio?

  Duke, duke, duke of Earl.

• 2:27Neil deGrasse Tyson?

  We'll find out what you're duke of. We'll come up with something.

• 2:29Paul Mecurio?

  Alright, okay. Greetings from Mangahela, Pennsylvania regarding the idea of time travel in star position. Hypothetically, if I were to create a time machine, attempt to go back to Mangahela two thousand years ago, would I not end up in empty space because the entire solar system would not have arrived in that location had I departed, that I had departed from?

• 2:51Neil deGrasse Tyson?

  Every time machine is also a space machine. They're spacetime machine. They don't say it, but they have to be.

• 2:58Paul Mecurio?

  Why is that relevant? Why does that matter?

• 2:59Neil deGrasse Tyson?

  They have to be. Now, they got around that in Back to the Future because when Marty is trying to escape from the Libyan terrorists and he jumps in the DeLorean and he's quickly typing the date, he types nineteen fifty-five, but it's the same day of the year as he leaves. So he goes back to nineteen fifty-five, Earth is in the same part of its orbit.

• 3:25Paul Mecurio?

  On that day.

• 3:26Neil deGrasse Tyson?

  Around the sun.

• 3:27Paul Mecurio?

  Because of the date, the date, the actual date.

• 3:29Neil deGrasse Tyson?

  The date was the same. So, so they skirted.

• 3:33Paul Mecurio?

  But that can't be true because over the years.

• 3:34Neil deGrasse Tyson?

  Hang on, hang on. So that, they dodged that bullet a little bit, okay? Had it been six months earlier or later, he'd just be plopped in the vacuum of space. He'd be dead, okay? So the reason why they dodged that bullet is because the entire solar system is also orbiting the center of the galaxy.

• 3:50Paul Mecurio?

  It happened to pick the exact date. That was the key there.

• 3:53Neil deGrasse Tyson?

  Well, only for the moving coordinate system that is the solar system.

• 3:57Paul Mecurio?

  Okay.

• 3:57Neil deGrasse Tyson?

  But because the whole solar system is moving, he goes back thirty years, he's leaving our solar system today, and if he only moved in time.

• 4:09Neil deGrasse Tyson?

  He would be where our solar system is today thirty years ago.

• 4:14Paul Mecurio?

  But he also.

• 4:15Neil deGrasse Tyson?

  He would have been well ahead of where the solar system would have gotten. The solar system would need another thirty years to catch up.

• 4:20Paul Mecurio?

  But he also moved in space is your point, not just in time.

• 4:23Neil deGrasse Tyson?

  Which is why he landed in exactly the same spot on earth. So, so it's implicit in the storytelling. So, you're absolutely right. Nothing, you can't do that in any way that makes sense.

• 4:34Paul Mecurio?

  But wait, if our solar system formed about four point six billion years ago, isn't the premise, part of his question has a false premise, which is I would not end up in this because the entire solar system would not have arrived in the location. Solar system is there in that location.

• 4:48Neil deGrasse Tyson?

  No, no, no, no. We're in a rotating galaxy. The Milky Way is rotating. And so, that is, all the stars in the Milky Way are rotating around our central black hole in the center. So, if you go back in time, if you go back in time, you are no longer where you left in space. And you'll be dropped in the middle of nowhere. So, you, you, you always have to land in a spacetime coordinate in the future. We sort of do that, but without the relativity part. If you're gonna visit Mars, you don't aim for where Mars is. You aim for where Mars will be when you get there. Then you intersect Mars.

• 5:29Paul Mecurio?

  So, if you're going back two thousand years, it will be an empty, well, there's gonna be a Home Depot, cuz they existed in a Subway sandwich shop. They, they've been around and.

• 5:38Neil deGrasse Tyson?

  In the mall, yeah.

• 5:39Paul Mecurio?

  Well, I mean, you know, their franchise and methodologies is brilliant and they've never gotten enough credit.

• 5:44Neil deGrasse Tyson?

  What, what, what you need is, you have to know where was the solar system and the earth two thousand years ago? And not only move back in time, but move back to that location.

• 5:54Paul Mecurio?

  But you cannot say that the Mangahela would not be the Mangahela two thousand years ago. Why wouldn't it be? Why would not it be exactly what it is today?

• 6:03Neil deGrasse Tyson?

  The Mangahela sounds like native, a native tribe.

• 6:06Paul Mecurio?

  It is.

• 6:06Neil deGrasse Tyson?

  That's who would be there. Two thousand years ago.

• 6:09Paul Mecurio?

  But he's asking if I create a time machine, if I have to go back to Mangahela, would I not end up in an empty space?

• 6:14Neil deGrasse Tyson?

  Yes, he would, unless he moved in time. That's what I've been spending the last ten minutes describing.

• 6:18Paul Mecurio?

  I understand that. So, your answer, you answered his question is yes.

• 6:22Neil deGrasse Tyson?

  Yes, unless he also moves back into, in space.

• 6:24Paul Mecurio?

  Base as well.

• 6:24Neil deGrasse Tyson?

  Correct.

• 6:25Paul Mecurio?

  Got it, okay.

• 6:26Neil deGrasse Tyson?

  And, yes, so every time machine is also a space machine. Otherwise, it would be quite lethal. Most of the time.

• 6:35Paul Mecurio?

  What would happen?

• 6:36Neil deGrasse Tyson?

  No, you get dropped in the middle of space. Because everything's moving. You gotta move with the action.

• 6:42Paul Mecurio?

  Okay, Margot Lane.

• 6:44Neil deGrasse Tyson?

  Mm-hmm.

• 6:44Paul Mecurio?

  If you were a life form on a pristine planet watching exploratory humans arrive for the first time. Okay, so you're observing humans arriving for the first time.

• 6:52Neil deGrasse Tyson?

  Yes.

• 6:52Paul Mecurio?

  What is the first question you'd ask them? Assuming you could understand each other, and I have the answer to this. My question would be, really, you needed Skechers shoes where you don't have to bend over to put them on? That's where you were as a species?

• 7:04Neil deGrasse Tyson?

  That meant you saw our TV commercials.

• 7:05Paul Mecurio?

  That, forget about that. That's where we are as a species. A lot of questions. The Kardashians. What? Why? Really?

• 7:12Neil deGrasse Tyson?

  What's up with that?

• 7:13Paul Mecurio?

  How do people who make Vaseline make any money? Think about it. I've had the same tub of Vaseline. My Vaseline was handed down to me by my grandfather in a will. I don't think you understand these conceptual, okay, here we go.

• 7:27Neil deGrasse Tyson?

  So, I think people used to use Vaseline before lotion was big.

• 7:31Paul Mecurio?

  I used it to grease the brakes on my car and I still have a giant vat of it.

• 7:35Neil deGrasse Tyson?

  Big tubs of Vaseline are not as, you know.

• 7:39Paul Mecurio?

  You could go through thirty thousand bags of garbage, you're not gonna find one empty container of Vaseline. Alright, so if you're a life form on a pristine planet watching exploratory humans arrive, what is the first question you would ask exploratory humans?

• 7:51Neil deGrasse Tyson?

  Okay. So first, let me say that you should look online. Maybe Pluto TV or one of these things that has old TV in it.

• 7:59Paul Mecurio?

  Mm-hmm. MeTV?

• 8:01Neil deGrasse Tyson?

  MeTV, yeah, but, and there's several others as well. Go to an old episode of The Twilight Zone called The Invaders. That's all I will say.

• 8:12Paul Mecurio?

  Well, I watch a lot of Twilight Zone. I'm trying to remember which one that is.

• 8:14Neil deGrasse Tyson?

  So, in that episode, Agnes Morehead is this lone ranch woman on a little house in the prairie. And the whole, it's a one-woman show. She's the only character in it. And you just have to watch that. It's called The Invaders.

• 8:30Paul Mecurio?

  Oh, I do remember this now.

• 8:32Neil deGrasse Tyson?

  It's called The Invaders. Don't say anything about it. Point is, if I'm the other life form and I see humans, my first question would be, just given what I know about humans, have you come to colonize this planet?

• 8:48Neil deGrasse Tyson?

  Because if that's your goal, that's not happening, okay? We will not let that happen, okay? Because we've seen what happens when you colonize stuff before.

• 8:56Paul Mecurio?

  Yeah.

• 8:57Neil deGrasse Tyson?

  Okay?

• 8:57Paul Mecurio?

  Yeah.

• 8:58Neil deGrasse Tyson?

  Uh, so, that's the first point. Second, I, that's interesting because that, that implies that the humans have more technology than the alien.

• 9:08Paul Mecurio?

  No, it doesn't.

• 9:08Neil deGrasse Tyson?

  Yeah, because otherwise the aliens would have visited us first.

• 9:11Paul Mecurio?

  No, that's, you're just jumping to conclusions.

• 9:13Neil deGrasse Tyson?

  No.

• 9:14Paul Mecurio?

  You're missing it. The question you gotta ask is, really, you conveyed happiness by a little yellow circle with a smiley face called an emoji? Like, there are so many bigger questions that you could ask these people.

• 9:25Neil deGrasse Tyson?

  Yeah, that's true.

• 9:26Paul Mecurio?

  No, the colonization is a good point, because nothing good ever has really happened from that. It's good and it's bad.

• 9:30Neil deGrasse Tyson?

  How about this? I would say, how did you survive yourselves?

• 9:36Paul Mecurio?

  Wouldn't?

• 9:36Neil deGrasse Tyson?

  Enough

• 9:38Paul Mecurio?

  Right.

• 9:38Neil deGrasse Tyson?

  to then come visit another planet?

• 9:41Paul Mecurio?

  Maybe what you would do is you would be hiding behind something and you'd say, how do you feel about brothers? You know, you gotta ask the black question, because, you know, because if they're not with the thing. No, maybe you just say, what part of the, are you from?

• 9:56Neil deGrasse Tyson?

  Oh, I see. Yeah, what part of the, the demographic?

• 9:58Paul Mecurio?

  Well, if you see them goose stepping down toward you, you probably know if you're a Jew or a black person, eh, you may wanna let them just pass.

• 10:06Neil deGrasse Tyson?

  Or gypsies, or Catholics.

• 10:08Paul Mecurio?

  Gypsies, or Catholics, or pretty much anybody.

• 10:10Neil deGrasse Tyson?

  Yeah, yeah, anyone non-Aryan.

• 10:12Paul Mecurio?

  Wouldn't you ask them how you got there, though? Seriously, what was your technology that got you to us?

• 10:16Neil deGrasse Tyson?

  I would assume they would see them land in something.

• 10:18Paul Mecurio?

  No, no, but, but you'd wanna learn from them.

• 10:20Neil deGrasse Tyson?

  As a scientist, I would compare notes.

• 10:22Paul Mecurio?

  Yeah.

• 10:23Neil deGrasse Tyson?

  And I would do things, there's certain things that should be common between us, even if we don't otherwise speak the same language.

• 10:31Paul Mecurio?

  You call Tang, like that kinda thing?

• 10:34Neil deGrasse Tyson?

  So, but how would I know that, though? That's what I'm saying. I don't know the Tang, or the Kardashians, or a slip-on skitters. I don't, I don't, unless he shows up drinking Tang.

• 10:43Paul Mecurio?

  Do you have to ruin every joke and party with your stupid logic?

• 10:46Neil deGrasse Tyson?

  With a Kardashian underarm and slip-on skitter. Then I could ask, what's up with that?

• 10:51Paul Mecurio?

  Why can't you presume that this, this life form is smarter and has the ability to see what we've been doing?

• 10:56Neil deGrasse Tyson?

  Here's what I would say. I wanna know, I wanna compare science notes, because science transcends time and space in ways culture does not.

• 11:07Paul Mecurio?

  But it doesn't transcend Instagram. If you got a big following, that's all that matters.

• 11:13Neil deGrasse Tyson?

  So, if I verify that they can see in the same wavelengths of light that I can see, they could have completely different senses.

• 11:21Paul Mecurio?

  Well, I was gonna think, say medically, you'd probably wanna check each other out too, right?

• 11:25Neil deGrasse Tyson?

  Not first, no.

• 11:26Paul Mecurio?

  No, I don't mean that.

• 11:27Neil deGrasse Tyson?

  Start poking their bodies first.

• 11:29Paul Mecurio?

  No, I didn't mean it in that way. No, I'm not talking about like anal probes or anything. I'm just saying, you thought of that.

• 11:35Neil deGrasse Tyson?

  Don't give the alien a bad name now.

• 11:37Paul Mecurio?

  No, I'm saying, no, why wouldn't, if you wanna check out their mind and compare notes in terms of science, wouldn't you physi, I would physically wanna understand their bodies versus, vis a vis my vessel. Their vessel, no, seriously.

• 11:50Neil deGrasse Tyson?

  If I'm a biologist, yes, but I'm a physicist, so no. I'd compare, I'd pull out a periodic table of the elements. Because that organization is universal. Anyone who knows the elements well enough, as well as we do, would organize them that way.

• 12:05Paul Mecurio?

  Okay, but what if somebody that landed was like a right, a creative writing major and didn't care about science?

• 12:10Neil deGrasse Tyson?

  If they were the first emissary to another planet, I'm pretty sure they would've given them some science.

• 12:14Paul Mecurio?

  Yeah, you're just a science snob. Only we're the ones that everybody cares about.

• 12:29Speaker 02

  I'm Jasmine Wilson, and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 12:43Paul Mecurio?

  Hello Neil and Paul, this is Julian Wright, Atlanta native, writing from downtown Manhattan. My question relates to stars and black holes. I understand that our sun belongs to the third generation of stars since the big bang. Each star will eventually die out in an explosion, some of which form black holes, ending in eternal singularity of their mass. Is it possible that in the distant future, there will be more black holes than stars, since their lifespan is so much longer than that of a star? Could the passage of time create a population of black holes that outlive and nearly replace stars?

• 13:18Neil deGrasse Tyson?

  Yes. Next question. So it turns out, according to Stephen Hawking, black holes actually evaporate, but very, very, very slowly.

• 13:27Paul Mecurio?

  So it's not burnout, it's evaporate, it's a different.

• 13:29Neil deGrasse Tyson?

  Yeah, they wouldn't burn out, very, very, very slowly. So there's a point where all the stars burn out, and they had, they leave their corpses. Some of those corpses are black holes. And there will come a time when the black hole, black holes outnumber the living stars. They will never outnumber the corpses.

• 13:46Paul Mecurio?

  But isn't the black hole then like, it's like the Alice in the Brady Bunch with a giant vacuum cleaner? It's like sucking up all of the stars, whether they evaporate or not?

• 13:57Neil deGrasse Tyson?

  I don't, Alice in the Brady Bunch?

• 14:00Paul Mecurio?

  Yeah, the housekeeper.

• 14:01Neil deGrasse Tyson?

  Is that what she did?

• 14:02Paul Mecurio?

  She was, she would vacuum.

• 14:04Neil deGrasse Tyson?

  The black holes?

• 14:06Paul Mecurio?

  Yeah.

• 14:06Neil deGrasse Tyson?

  I'm sorry, I can't connect. I'm sorry. But do you see, where was Alice in the grid of nine squares?

• 14:13Paul Mecurio?

  She was in the center.

• 14:14Neil deGrasse Tyson?

  She was in the center, and if you notice, her image kept repeating back and forth.

• 14:18Paul Mecurio?

  Because they didn't have the technology.

• 14:19Neil deGrasse Tyson?

  It was a pretty short loop.

• 14:20Paul Mecurio?

  Right.

• 14:21Neil deGrasse Tyson?

  And I got annoyed by it.

• 14:22Paul Mecurio?

  It's the same thing in the Mad Mad Mad Mad world.

• 14:25Neil deGrasse Tyson?

  Yeah.

• 14:25Paul Mecurio?

  Um, I just saw it last night.

• 14:27Neil deGrasse Tyson?

  Really?

• 14:27Paul Mecurio?

  No, I'm serious.

• 14:28Neil deGrasse Tyson?

  Okay, I know every frame of that movie.

• 14:30Paul Mecurio?

  Okay, so there's the shot when, at the end, Spencer Tracy is hanging on to the edge of, uh, he slides down a cable and goes through a window, and is sitting there, and a Great Dane is licking his face.

• 14:43Neil deGrasse Tyson?

  Yes, and that to repeat it.

• 14:44Paul Mecurio?

  And it's repeated, and it was annoying me as well.

• 14:49Paul Mecurio?

  I don't know how he got off on that, but it's like, and, and he's doing this with his eyes move the same way. Um, but is it possible there are already more black holes than this, than stars in our universe?

• 14:59Neil deGrasse Tyson?

  No, because we know who the progenitor is of a black hole. And it's a star that's made one out of 10,000 stars. Or one in a million star, it's, it's the most massive of stars is a black hole. And in any volume of gas that creates stars, it creates a lot of low-mass stars and fewer middle-mass stars and very few high-mass stars.

• 15:25Paul Mecurio?

  So is this like a cosmic game of hide and seek?

• 15:27Neil deGrasse Tyson?

  Well, it's called the initial mass function specifically. And the initial mass function favors low-mass stars and high-mass stars are just rare. Rare. And I don't know the latest iteration on the initial mass function, but it's at least as rare as one in a thousand stars.

• 15:45Paul Mecurio?

  That what?

• 15:46Neil deGrasse Tyson?

  Are massive enough to make a black hole at the end of its life. So, all I'm saying is, we have stars today that are born out of these pockets of gas that are still alive and thriving, and we've only had one or two black holes. So, no. Black holes do not outnumber stars. By the way, they will outnumber stars in a trillion years, a few trillion years, when the lowest-mass stars burn out their fuel.

• 16:11Paul Mecurio?

  That sounds like stars need like a support group for black holes in the way they get dealt with.

• 16:15Neil deGrasse Tyson?

  No, they'll be fine. Black holes need no support.

• 16:18Paul Mecurio?

  The more black holes that develop, we're all in jeopardy, no?

• 16:22Neil deGrasse Tyson?

  I just avoid them, that's all.

• 16:23Paul Mecurio?

  Well, but what you do emotionally in your relationships to other people is not what's relevant here.

• 16:28Neil deGrasse Tyson?

  Yeah, we just need a map of where all the black holes are and then step around them.

• 16:35Neil deGrasse Tyson?

  Especially in your time machine. You don't want your time machine to land in a black hole because you didn't type in the right spacetime coordinate.

• 16:41Paul Mecurio?

  All right, let's move on. I think we answered that thoroughly. Cesar Fredic from Bogota, Colombia.

• 16:48Neil deGrasse Tyson?

  Love it.

• 16:48Paul Mecurio?

  Uh, "Speed of light C shapes our reality and its fundamental properties. However, it is intriguing to consider that regardless of the unit used, C could potentially be half double or any other value. Could you suggest factors, other than the possibility of it being an imposed constraint within a simulation, that might determine the seemingly arbitrary value of this universal constant as we understand it?"

• 17:15Neil deGrasse Tyson?

  Wow. Here's a couple of speed of light facts.

• 17:19Paul Mecurio?

  Two-hundred-and-ninety-nine million, seven-hundred-and-ninety-two, four-hundred-and-forty meters per second.

• 17:23Neil deGrasse Tyson?

  Yes. Yes.

• 17:25Paul Mecurio?

  And do you know where the C comes from? The Latin word "speed"?

• 17:29Neil deGrasse Tyson?

  C stands for... Constant.

• 17:32Paul Mecurio?

  Yeah, but they think that there's a speculation from a 1922 historian and scientist that it's celitrius, the Latin for speed.

• 17:42Neil deGrasse Tyson?

  That's the first I've heard of that.

• 17:44Paul Mecurio?

  Well, that's why I'm here to open your horizon.

• 17:46Neil deGrasse Tyson?

  That's the first I've heard of that.

• 17:48Paul Mecurio?

  It's true.

• 17:49Neil deGrasse Tyson?

  First I've heard of that.

• 17:51Paul Mecurio?

  That doesn't mean it's not.

• 17:52Neil deGrasse Tyson?

  It's the most fundamental constant in the universe.

• 17:54Paul Mecurio?

  Right.

• 17:55Neil deGrasse Tyson?

  And the word constant begins with a C.

• 17:57Paul Mecurio?

  I understand that, but there's another.

• 17:59Neil deGrasse Tyson?

  So if I'm wrong, I'd be intrigued to learn that that's what was really going on.

• 18:04Paul Mecurio?

  Okay.

• 18:04Neil deGrasse Tyson?

  It's not just an after the fact suggestion.

• 18:07Paul Mecurio?

  Okay.

• 18:07Neil deGrasse Tyson?

  So, the units are arbitrary, completely arbitrary. You said you're, how tall are you, five nine?

• 18:15Paul Mecurio?

  Mm-hmm.

• 18:16Neil deGrasse Tyson?

  If I measured your height in units of five nine-ness, then how tall are you?

• 18:22Paul Mecurio?

  Those unit, those number of units of five nine.

• 18:25Neil deGrasse Tyson?

  If I have a new unit that's five feet nine inches.

• 18:28Paul Mecurio?

  And I'm one unit.

• 18:28Neil deGrasse Tyson?

  You're one.

• 18:31Paul Mecurio?

  Okay, so your point being.

• 18:32Neil deGrasse Tyson?

  That doesn't make you shorter or taller or anything.

• 18:33Paul Mecurio?

  But your point.

• 18:34Neil deGrasse Tyson?

  I'm saying that the units are arbitrary, but the speed that we're measuring is not. That is real and it's fundamental.

• 18:41Paul Mecurio?

  So the units don't matter.

• 18:42Neil deGrasse Tyson?

  And so precisely do we understand the speed of light. It's been measured so precisely that it defines the length of the meter. That's how well we know the speed of light. So if we get another point of precision in the measurement of the speed of light, it affects the definition of the length of the meter.

• 19:08Paul Mecurio?

  So you can vary that.

• 19:10Neil deGrasse Tyson?

  Well, only in the points where it's still uncertain, that's correct. But it's the most amazing fundamental thing there is.

• 19:17Paul Mecurio?

  So there is no inherent, there cannot be any inherent uncertainty around the speed of light, is what you're saying?

• 19:23Neil deGrasse Tyson?

  Whatever uncertainty there is, it's smaller than our capacity to measure it.

• 19:28Paul Mecurio?

  Then how do you know that there is uncertainty if you can't measure it?

• 19:30Neil deGrasse Tyson?

  There is always uncertainty in every measurement.

• 19:34Paul Mecurio?

  How do we know that?

• 19:35Neil deGrasse Tyson?

  Always.

• 19:36Paul Mecurio?

  How do we know that?

• 19:37Neil deGrasse Tyson?

  So, how tall are you, again?

• 19:39Paul Mecurio?

  Five nine.

• 19:40Neil deGrasse Tyson?

  Are you five nine and a quarter? Are you five eight and three quarters? Are you five eight and seven eighths? Are you five nine and one eighth? Are you five nine and one sixteenth? How come you gave it to me in units of inches? You've approximated, haven't you? Well, it depends on what socks I'm wearing. You have approximated it. So, now I measure you at five nine, let's say you're exactly five nine, five feet nine inches. What does that even mean? The thickness of the line, that's the nine inches above the five feet. Where are you within the thickness of that line? Are you five eight and ninety-nine one hundredth of an inch? Are you five nine and one one thousandth of an inch? So you're saying exactitude is impossible? Correct. Always, everywhere.

• 20:24Neil deGrasse Tyson?

  You can never measure something exactly. Is that it because of the space-time continuum? No, it's, it's, what's called measurement errors. But they're not errors, they're just measurement uncertainties. So, if you were once five eight, and then you're later on five ten. There was a point in your life where you were exactly five nine. But you could have never measured it to be so. Right. All you could do is measure it and bracket it according to the uncertainties of your measuring device. Right now, I'm exactly five nine, I felt it. With a little vibration. Little vibration. So, measurements are never exact. And they never can be. And they never will be. That's correct. You can only know them with greater precision. And you're how tall?

• 21:09Neil deGrasse Tyson?

  At my tallest, six two. But you're shrinking. Yeah, I'm probably shrinking. Is that your spine collapsing? The, the discs between your spinal column. Fluid. Yeah, but you can go into space and grow an inch or so. But your space suit that you walk in, in the spacewalk, is made taller than the one you took off in. Why are we growing? Because gravity, the atoms. Gravity's no longer squashing you. So the atoms are getting stretched. Yeah, the molecules, it stretches out, right. So, I'm probably six one and three quarters now, I guess. You are, as they say in science, a tall drink of water. All right, here we go. Doesn't that mean you have great affection for me?

• 21:47Paul Mecurio?

  Knows no bounds. It's boundless. Alright, Stefan Summers. Uh, this is Stefan from Heston, Kansas. I was making my way through your old-

• 21:57Neil deGrasse Tyson?

  These are some small towns, I love it.

• 21:58Paul Mecurio?

  Yeah. Making my way through your old queries and found one where you talked about how if we could pass through wormholes, then gravity would as well, but my understanding is that gravity is the warping of space, and since a wormhole is making a hole through the dimension of space, would it be warped on the other side? Furthermore, if a wormhole is a literal hole through a dimension, would we be able to pass through it or even perceive it as beings who live within our three-dimensional space?

• 22:32Neil deGrasse Tyson?

  Wow.

• 22:32Paul Mecurio?

  You want me to-

• 22:33Neil deGrasse Tyson?

  That sounds like he wants to write another, the sequel to-

• 22:35Paul Mecurio?

  I was gonna say, do you want me to repeat anything?

• 22:36Neil deGrasse Tyson?

  No, no, no, no, no. He wants to write the sequel to Interstellar. That's what he's trying to do there.

• 22:41Paul Mecurio?

  Yes, exactly.

• 22:42Neil deGrasse Tyson?

  So, a wormhole uses, if we were to make one, uses negative gravity. So we know how to make a wormhole, we just don't have the stuff, the substance, to make it happen. Gravity collapses spacetime on itself. Negative gravity, if we could, negative matter, would pry open spacetime.

• 23:03Paul Mecurio?

  And creates a shortcut through-

• 23:05Neil deGrasse Tyson?

  So if we did that, we in principle should be able to position it in such a way that pops a hole through the fabric of space and time. You step through and you're instantly on the other side. Which, by the way, would have rendered transporters completely obsolete in Star Trek. Think about it. Just step through a wormhole to get down to the planet.

• 23:23Paul Mecurio?

  Yeah, but there's no guarantee you're gonna get through without getting lost. It's like Google Maps and you take a right and suddenly you're in a cornfield.

• 23:29Neil deGrasse Tyson?

  I'll take that chance.

• 23:30Paul Mecurio?

  Cause you don't pay attention to Google Maps.

• 23:31Neil deGrasse Tyson?

  I'll take that chance over dematerializing my body into energy and re-materializing it back into matter on the other side.

• 23:40Paul Mecurio?

  Why do you think that that's not possible? Because you're like-

• 23:43Neil deGrasse Tyson?

  I'm-

• 23:43Paul Mecurio?

  Your nose ends up on your butt cheek?

• 23:45Neil deGrasse Tyson?

  I know, anything. Anything. My thoughts, my memories, stored in the synapses of my brain? I don't know what's gonna do that.

• 23:53Paul Mecurio?

  Maybe you could help. Let's say you've misplaced your keys all the time. Suddenly think that we arranged. You know where your keys are at all the time.

• 24:01Neil deGrasse Tyson?

  That's a possibility. But the brain is so complex, I'm guessing that if you dematerialize it and re-materialize it, chances are you'll mess it up rather than improve it.

• 24:10Paul Mecurio?

  Okay, but if we're 3D and a wormhole is in another dimension, how do we even know it's there? It's like trying to change a flat not knowing where the car is.

• 24:17Neil deGrasse Tyson?

  We see the part of the wormhole that intersects our dimensionality.

• 24:22Paul Mecurio?

  But it's only part of the wormhole.

• 24:24Neil deGrasse Tyson?

  Well. So, here's an example I gave in another show. If we live in a flat sheet of paper, and then we're just standing around and we see a dot just appear out of nowhere. That dot becomes a small circle, and then a big circle, just watching this. And then it shrinks back again, becomes a dot and then disappears. That'd be freaky.

• 24:47Paul Mecurio?

  No, that's called a Vegas act. It's a magician, he works at the lounge.

• 24:51Neil deGrasse Tyson?

  It's completely freaky.

• 24:52Paul Mecurio?

  Bellagio.

• 24:53Neil deGrasse Tyson?

  What you just witnessed was a three-dimensional sphere passing through the two dimensions of your world. And you described it as a point, and then circles that grew, until the circle was as wide as the diameter of this sphere. And then it went back and then disappeared as it passed through to the other side. So, higher-dimensional things passing through our dimensionality will manifest in some way or another.

• 25:22Paul Mecurio?

  So in answering this question then, the answer is, if a wormhole's a literal hole through a dimension, will we be able to pass through it or even perceive it as being, as beings who live within our three dimensions?

• 25:33Neil deGrasse Tyson?

  Yeah.

• 25:34Paul Mecurio?

  You can perceive it.

• 25:35Neil deGrasse Tyson?

  You would see the part of the wormhole that intersected our dimensionality.

• 25:37Paul Mecurio?

  But nothing more than that.

• 25:38Neil deGrasse Tyson?

  You won't appreciate all of what else is going on there. The fact that it moves into a fourth dimension, you're not gonna catch that.

• 25:44Paul Mecurio?

  But if you're passing through a wormhole, you're gonna instantly get to the other side.

• 25:50Neil deGrasse Tyson?

  Instantly. Instantly. So, would movies like showing that you're going through this tunnel? You know, it's like in the water park? No, it's correctly done in Rick and Morty.

• 26:04Paul Mecurio?

  Which is exactly why I watch Rick and Morty. For my science knowledge.

• 26:07Neil deGrasse Tyson?

  And this dude, what's his name, Doctor Strange.

• 26:11Neil deGrasse Tyson?

  You know who I'm talking about?

• 26:12Paul Mecurio?

  I would, if I had a superpower, I just would wanna be able to do that. It's a very sophisticated understatement. It's not this, it's not trying too hard, it's like, eh.

• 26:21Neil deGrasse Tyson?

  Yeah, I mean, I prefer the Rick and Morty wormholes, cuz Rick uses real science.

• 26:27Paul Mecurio?

  And what is it about that wormhole in Rick and Morty that's accurate to you?

• 26:31Neil deGrasse Tyson?

  No, he just uses real science, whereas Doctor Strange uses magic.

• 26:37Paul Mecurio?

  If you can't perceive a wormhole, aren't we in a way like walking through life like this tourists that are lost in New York City, just looking up, taking pictures at everything?

• 26:44Neil deGrasse Tyson?

  Yes.

• 26:45Paul Mecurio?

  And isn't there a way that science can sort of make us not feel that way?

• 26:52Neil deGrasse Tyson?

  Deal with it. You can't become a scientist unless you are comfortable being steeped in ignorance.

• 26:57Paul Mecurio?

  Okay, so we have this constant debate. This is where you just like try to get off on being lazy and not trying to get stuff right?

• 27:03Neil deGrasse Tyson?

  No, I wanna get stuff right.

• 27:04Paul Mecurio?

  Whoa, whoa, it's better to not know anything. Alright, let's go have a bottle of wine.

• 27:07Neil deGrasse Tyson?

  No, it's learn to love the questions themselves.

• 27:11Paul Mecurio?

  Oh my god. I went through law school, I don't need this ad to answer a friggin' question, will ya? You know, talking to you about science, like looking at a Picasso and then you're like, whoa, why is his nose on his calf? I don't know. And then some historian, artist or he has a theory, and they're completely full of you-know-what. Okay, you know what, you're fired from science.

• 27:31Neil deGrasse Tyson?

  I don't think he ever put his nose on his calf.

• 27:33Paul Mecurio?

  Yes, he did. Alright, here we go. Oh, this is Captain Carl with two K's, everybody. Ahoy, Captain Carl from St. Thomas, US Virgin Islands. I've often wondered, as a photographer and as physics enthusiast, is our colorful world a result of our white star? White being made up of all colors. What if our planet, or any planet, was orbiting a blue or red star? Would our world be different shades of red or blue? By the way, I just wanna thank you, Neil, and shout out to your comedic sidekicks. So would our worlds be different shades of red or blue if we were orbiting a blue or red star?

• 28:07Neil deGrasse Tyson?

  With our current eyes, yes. But if we evolved there, there's no reason why our evolutionary path wouldn't have take, divided up the blue light into different subcategories.

• 28:19Paul Mecurio?

  Yeah, but if you have pure red, then entire Earth's gonna feel like a brothel.

• 28:22Neil deGrasse Tyson?

  Yeah, however-

• 28:23Paul Mecurio?

  Don't pretend you don't know what that is.

• 28:25Neil deGrasse Tyson?

  The width of our sensitivity to light is much greater than any single band of light.

• 28:30Paul Mecurio?

  Say that again, you lost me.

• 28:32Neil deGrasse Tyson?

  Alright, so you have Roy G. Biv.

• 28:36Neil deGrasse Tyson?

  Do you know Roy G. Biv? You don't know Roy? Red, orange, yellow, green, blue, indigo, violet. Roy G. Biv.

• 28:42Paul Mecurio?

  Okay.

• 28:43Neil deGrasse Tyson?

  You never knew?

• 28:43Paul Mecurio?

  No, I never, no.

• 28:44Neil deGrasse Tyson?

  You gotta learn something every day.

• 28:45Paul Mecurio?

  Yeah, that's why I'm here.

• 28:46Neil deGrasse Tyson?

  Okay. Okay, Roy G. Biv. We see all those colors. Now, when we make color photos by Hubble or the James Webb Telescope, in the infrared part of the spectrum, you can't see colors in the infrared part of the spectrum. So you know what we do? We take RGB, slap it onto different wavelengths in the infrared part of the spectrum, and create a color photograph out of it. That's what you would see if our sight was shifted to the infrared part of the spectrum. It's what the world would look like.

• 29:20Paul Mecurio?

  So the infrared part of the spectrum, is it neutral in color?

• 29:24Neil deGrasse Tyson?

  You can't detect it at all. But, if we evolved to see it, there's no reason to think our brain wouldn't assign colors to it. That's what's going on here. We're assigning colors. In fact, Richard Dawkins, the evolutionary biologist, thinks that bats, actually, when they echolocate, they see in color. Because their mammal brain has that capacity. So why not use it?

• 29:49Paul Mecurio?

  So-

• 29:49Neil deGrasse Tyson?

  So when you're using echolocation, tag it with a color.

• 29:53Paul Mecurio?

  So if we orbited, if we orbited a blue star, we'd still have, would we still have clear skies? In other words,

• 29:59Neil deGrasse Tyson?

  If we, if our eyes evolved in this star, and then transport us to a blue star, right? Then, we would not see colors in the blue, because we can only see colors in the visible part of the spectrum. There'd be blue and ultraviolet, ultraviolet. We only see colors in the visible part of the spectrum. However, you can fake it, authentically fake it.

• 30:25Paul Mecurio?

  That's called the perfect Instagram filter.

• 30:27Neil deGrasse Tyson?

  Right? So going in that direction, we have violet, take three bands in violet light. They're adjacent to one another. Then, once you do that, you assign RGB, bring them back together, and you can reconstruct what you would see if our sensitivity were shifted to the violet and ultraviolet part of the spectrum, to the blue part of the spectrum. So, we should think of it as shifted color, is what it is.

• 30:54Paul Mecurio?

  But we're only limited in how much we can, our abilities to shift.

• 30:57Neil deGrasse Tyson?

  We're very limited.

• 30:59Paul Mecurio?

  Well, you are, I'm not.

• 31:02Neil deGrasse Tyson?

  So, we see red through violet, that's it.

• 31:06Paul Mecurio?

  And that's.

• 31:06Neil deGrasse Tyson?

  If I want to see color anywhere else, you take out the RGB, slap it down on three different bands, and out comes a color picture of X-rays, of infrared, of ultraviolet, of gamma rays, all the above.

• 31:21Paul Mecurio?

  And so, a red planet, a blue planet, a red star, a blue star, is there any star with a color that you have the ability to see without sort of slapping our, that, doing that technique?

• 31:35Neil deGrasse Tyson?

  RBG?

• 31:36Paul Mecurio?

  Yeah, RBG.

• 31:37Neil deGrasse Tyson?

  Roy, say it, Roy G. Bib.

• 31:40Paul Mecurio?

  Roy G. Bib.

• 31:40Neil deGrasse Tyson?

  So, no, just the way we evolved, we can't, we can't see into it. So, by the way, this band of visible light is very narrow compared with ultraviolet or infrared, very narrow. So, we're practically blind no matter what. And insects see into the deep ultraviolet, insects, and they're perfectly happy.

• 32:02Paul Mecurio?

  When I stare into a very bright light and then I can't see for a second, what's happening?

• 32:05Neil deGrasse Tyson?

  That's a different thing. You, you, you overstimulate the retinal cells.

• 32:10Paul Mecurio?

  Which is.

• 32:10Neil deGrasse Tyson?

  They have to recover.

• 32:11Paul Mecurio?

  Yeah, which takes several seconds.

• 32:13Neil deGrasse Tyson?

  Yeah, yeah.

• 32:14Paul Mecurio?

  Yeah. Which is always fun, by the way, after you've been drinking.

• 32:17Neil deGrasse Tyson?

  Eh.

• 32:18Paul Mecurio?

  Uh, all right, another question. Hello, I'm John Mahui, uh, Mahoy, Mahoy, there you go, uh, and from Parkland, Florida. I know that the cosmic microwave background is like a snapshot of the early universe, and its temperature has been dropping ever since. So, I'm wondering, could this temperature be used as a kind of universal clock? If we could measure it super accurately, would that tell us exactly how old the universe is right now? Would that age be the same no matter what, where you are in the universe?

• 32:49Neil deGrasse Tyson?

  Yes. Because every part of the universe was in the same place at the same time, 13.8 billion years ago.

• 32:59Neil deGrasse Tyson?

  So, the oldest things in the universe, in every direction you look, are exactly the same age, traceable to that period of time. So, yeah, everything. Now, at this moment, we see in the past, so we can ask, what is that thing doing now? Well, it's even farther away from us. It's, and we can think of the diameter of the universe, as how big the universe is today, even though you can't see that, and that diameter is coming in at ninety-six, something like that, billion miles, full diameter. So if you could see those galaxies out of horizon today, that's what they look like. But that would need an infinite speed of light.

• 33:40Paul Mecurio?

  And that's-

• 33:41Neil deGrasse Tyson?

  I'm not, we're not giving you that.

• 33:42Paul Mecurio?

  Why? Not possible.

• 33:44Neil deGrasse Tyson?

  Not giving it to you. Observational limits on the universe.

• 33:50Paul Mecurio?

  And temperatures, the only way to measure this, is to have a universal clock, is-

• 33:55Neil deGrasse Tyson?

  Temperature also works. Yeah, so, as the universe grows, the temperature cools. So it's a, it's a one-to-one correspondence. So you can just backstrapulate to the early universe-

• 34:06Paul Mecurio?

  So there's a murder scene, and they do a forensic-

• 34:09Neil deGrasse Tyson?

  Why are you so morbid?

• 34:10Paul Mecurio?

  Well, because that's how my brain thinks. Uh, and they, and they, and so they can figure out, based on the temperature of the body, when the body died.

• 34:18Neil deGrasse Tyson?

  Yes.

• 34:19Paul Mecurio?

  So that's what's happening there.

• 34:20Neil deGrasse Tyson?

  I hadn't thought about it that way, but that's, that works.

• 34:22Paul Mecurio?

  Yeah, you got the crusty old cop, and then you got the-

• 34:25Neil deGrasse Tyson?

  That's right.

• 34:26Paul Mecurio?

  You got the sexy sidekick.

• 34:27Neil deGrasse Tyson?

  That's right.

• 34:27Paul Mecurio?

  Male or female?

• 34:28Neil deGrasse Tyson?

  I hadn't thought about that.

• 34:29Paul Mecurio?

  Well, that's why I'm here.

• 34:30Neil deGrasse Tyson?

  What's the next question?

• 34:32Paul Mecurio?

  Okay. This is, uh, Joe Liparrela, Liparrela, from, uh, Pennsylvania. Relativity tells us that as an object approaches the speed of light, or is in a deep gravitational well, time slows to a stop relative to other observers. My question is, what is on the other side of that extreme? If an object is motionless, and if there is zero gravitational effect on it, how would time work for that object?

• 34:57Neil deGrasse Tyson?

  If there's zero gravity, then time goes fast for it.

• 35:04Paul Mecurio?

  Well, an object is motionless, and if there's zero gravitational effect on it-

• 35:08Neil deGrasse Tyson?

  Right, so-

• 35:09Paul Mecurio?

  How would time work?

• 35:10Neil deGrasse Tyson?

  When you are in the presence of gravity, you age slower.

• 35:12Paul Mecurio?

  So this is like the ultimate anti-aging hack?

• 35:17Paul Mecurio?

  This is, we should bottle this. We should be on QVC right now, not on this dog and pony show you call StarTalk. We could be making some big bucks.

• 35:26Neil deGrasse Tyson?

  Start our own, our own QVC channel.

• 35:28Paul Mecurio?

  Yeah, Dr. Tyson's QVC hack.

• 35:31Neil deGrasse Tyson?

  So what are they asking them?

• 35:33Paul Mecurio?

  They're asking, my question is, what is on the other side of that extreme? In other words, relativity tells us that as an object approaches the speed of light, or is in a deep gravitational well, time slows to a stop.

• 35:46Neil deGrasse Tyson?

  Okay, so now what? So, some years ago, people realized you couldn't accelerate past the speed of light. But does that preclude a particle existing faster than light? If you can't accelerate past it, can you exist on the other side? And, serious thought was given to that. To the point where there's some movies based on it. And we, there was a hypothetical particle that has these properties. It's called a tachyon. Tachios from the Greek meaning fast. Tachios. Tachions. And tachions would live backwards in time.

• 36:21Paul Mecurio?

  How is that possible?

• 36:22Neil deGrasse Tyson?

  Because, if time slows down as you reach the speed of light, on the other side of speed of light, if you continue the equations, jumping that gap, time would go backwards for it.

• 36:34Paul Mecurio?

  For it, for?

• 36:36Neil deGrasse Tyson?

  Yes, yeah, for it.

• 36:38Paul Mecurio?

  Do we know they exist?

• 36:39Neil deGrasse Tyson?

  No, we never, never found them.

• 36:41Paul Mecurio?

  So then how could you have a theory about something that you?

• 36:43Neil deGrasse Tyson?

  Because it's allowed to exist by Einstein's equations. If something is allowed, that's good enough reason to go out and look for it. If other parts-

• 36:51Paul Mecurio?

  But at one point, do you stop looking in all seriousness and go, this doesn't, if you can't find it?

• 36:56Neil deGrasse Tyson?

  Welcome to the frontier of science.

• 36:58Paul Mecurio?

  No, it's like, I can't find my phone in my house, I'm not gonna keep looking, go, I know it's there.

• 37:01Neil deGrasse Tyson?

  We don't know. That's right. It's a mystery. But if you give up and someone else finds it a month later-

• 37:07Paul Mecurio?

  So when time meets an object with no gravity and no movement, it's like my lazy, good-for-nothing 15-year-old son who won't mow the lawn, right? He just lays, just sits there. So the answer to the question is, yes. On some, is it, or is it that clear?

• 37:23Neil deGrasse Tyson?

  The answer is, weren't there two parts to that?

• 37:26Paul Mecurio?

  Yeah, there's the, an object approaches the speed of light, or is in a deep gravitational well, time slows to a stop.

• 37:32Neil deGrasse Tyson?

  Yes, in a deep gravitational well, yes, time slows.

• 37:34Paul Mecurio?

  Okay. And what is on the other side of that extreme?

• 37:37Neil deGrasse Tyson?

  And that would be tachyons.

• 37:39Paul Mecurio?

  Tachyons, which we know there, but we haven't found them. Okay.

• 37:42Neil deGrasse Tyson?

  Correct.

• 37:42Paul Mecurio?

  Got it.

• 37:43Neil deGrasse Tyson?

  The tachyons work in the equations.

• 37:45Paul Mecurio?

  So as a result?

• 37:47Neil deGrasse Tyson?

  And so we're saying, well, right all these other ways, maybe this prediction of the equation should work as well.

• 37:51Paul Mecurio?

  Got it.

• 37:52Neil deGrasse Tyson?

  So if you are motionless in space, as far as you're concerned, you'll still have your own timeline, and all that matters is what other people will say of you as they fly by you. So everyone will have a different time reference for you. All you care about is your own clock, and your own wristwatch, and your own clock on the wall. And that's all you care about. Now, that's if you're not moving. But if there's no gravity, then time speeds up for you.

• 38:21Paul Mecurio?

  So if an object is motionless, and there's zero gravitational effect, how would time work for that object? This is where we're talking, so this is where we were joking about anti-aging hack, right? So in other words, there'd be no aging, because time, there's, right? There's zero gravitational effect.

• 38:40Neil deGrasse Tyson?

  Yeah, but you and everyone else around you, in your same reference frame, will age at exactly the same rate. It could be one second for every 10 seconds outside of your club.

• 38:51Paul Mecurio?

  Right.

• 38:51Neil deGrasse Tyson?

  Right? But it won't matter to any of you. You can't hack that system and say, "I want to go back to when I was younger."

• 38:58Paul Mecurio?

  Okay, but if you're so smart, tell me who in that group is going to get plastic surgery first to avoid the aging process?

• 39:04Neil deGrasse Tyson?

  Yeah, plus if you're in space with zero G, some surgeries aren't necessary.

• 39:11Paul Mecurio?

  No, well, you're right, because you got nothing pulling on you.

• 39:15Neil deGrasse Tyson?

  Nothing pulling on you. Stuff floats.

• 39:17Paul Mecurio?

  That's what we should invent. We should invent people, zero G facial surgery.

• 39:42Paul Mecurio?

  I like this question. It's very simple, straightforward, but interesting. Dennis Alberti, please explain buoyancy.

• 39:49Neil deGrasse Tyson?

  Buoyancy? I love it. Alright, so, it's all about density. In the end of the day, it's about density.

• 39:57Paul Mecurio?

  And gravity, you know?

• 39:58Neil deGrasse Tyson?

  So, if you are, and gravity, yes. If you are less dense than the medium you're immersed in, you will float to the top. It's that simple. It's not more complicated than that.

• 40:08Paul Mecurio?

  Define density.

• 40:10Neil deGrasse Tyson?

  It's how much matter you can cram into a certain volume. So, the big advance, it's amazing this didn't happen until the 19th century, was there was some early variants in the 18th century, but it really took off in the 19th century. The fact that you could float metal. If you make a boat out of metal, then it's almost impervious to war.

• 40:34Paul Mecurio?

  Not icebergs.

• 40:37Paul Mecurio?

  And a billion-dollar gross at the movies.

• 40:40Neil deGrasse Tyson?

  It's exactly what Titanic did. It was probably up to 2 or 3 billion now.

• 40:45Paul Mecurio?

  Look, to summarize it, a submarine is a boat in denial.

• 40:48Neil deGrasse Tyson?

  Well, so here's what happens. So...

• 40:50Paul Mecurio?

  You should react to that. That was a good line.

• 40:54Neil deGrasse Tyson?

  So...

• 40:54Paul Mecurio?

  A submarine is a boat in denial.

• 40:57Neil deGrasse Tyson?

  So, if you have a hull that's made of metal, any bits of that metal would just sink to the bottom. However, if it's in the hull shape, it's pressing down on the water. The water is rising up, and you've created an environment that, on average, is less dense than water, and so therefore it floats.

• 41:15Paul Mecurio?

  Because of the V shape?

• 41:16Neil deGrasse Tyson?

  Because most of the volume is air. So, you get to add the air plus the metal as part of the contents that's within the volume. And when you do that, you systematically reduce the density of the material. If you go back 1,000 years ago, people made boats out of wood. Sensibly, because wood floats. So you would make anything out of wood, it would float. That made complete sense, but you're susceptible to attack.

• 41:45Paul Mecurio?

  But if I took a metal plank, a four by twelve piece of metal, flat, and threw it in the water, would that sink?

• 41:55Neil deGrasse Tyson?

  Yes.

• 41:57Paul Mecurio?

  Because you don't have that V shape, you don't have the relation to air.

• 42:01Neil deGrasse Tyson?

  Correct, because it's all about volume. It's all about volume. So if you carve it into a volume, then it's the mass of the shell divided by the full volume of the whole thing. And that gets very low to be lower than water. It'll just float.

• 42:16Paul Mecurio?

  It's the same principle why an iceberg can float, because you've

• 42:19Neil deGrasse Tyson?

  Icebergs are just simply less dense than water.

• 42:22Paul Mecurio?

  Right.

• 42:22Neil deGrasse Tyson?

  Simply less dense.

• 42:24Paul Mecurio?

  So you don't need that V shape for that to

• 42:27Neil deGrasse Tyson?

  For an iceberg, no.

• 42:28Paul Mecurio?

  No.

• 42:28Neil deGrasse Tyson?

  No. I mean, you don't ever need a V shape, except that, I mean, like Styrofoam will make a boat, but it doesn't need a V shape.

• 42:36Paul Mecurio?

  Right.

• 42:37Neil deGrasse Tyson?

  V shapes are important if you know the material you're working with is heavier than than the stuff itself.

• 42:42Paul Mecurio?

  Right, because you're, you want to displace.

• 42:45Neil deGrasse Tyson?

  Correct.

• 42:45Paul Mecurio?

  Right, it's all about displacement.

• 42:47Neil deGrasse Tyson?

  Correct.

• 42:48Paul Mecurio?

  So the bottom line is, um, icebergs float. You got a V shaped hull, steel, float.

• 42:54Neil deGrasse Tyson?

  Yes.

• 42:55Paul Mecurio?

  Styrofoam cooler, best scenario. You can sit on it and tap in and get a couple of beers at the same time.

• 43:01Neil deGrasse Tyson?

  At the same time.

• 43:02Paul Mecurio?

  Okay, that's why I'm here.

• 43:03Neil deGrasse Tyson?

  Paul, I've got time for one more.

• 43:04Paul Mecurio?

  One more, got it. Okay, this is a, this is actually a very interesting one. Terry Burke from St. Louis. My question is simple. In nuclear fission and fusion, a small amount of matter is lost and converted to a large amount of energy. Is the gravity associated with the lost mass also lost?

• 43:22Neil deGrasse Tyson?

  No, because, great question, by the way. Gravity emanates not only from mass, but also from energy. Because mass and energy are the same thing. Different sides of the same coin. So, you're not just losing mass and not energy. You're losing some combination of the two and they go hand in hand.

• 43:39Paul Mecurio?

  So the answer is no, is the gravity associated with the lost?

• 43:43Neil deGrasse Tyson?

  No.

• 43:44Paul Mecurio?

  And that can never vary? I mean thi- this is, this is a con- this is a constant, this can never, this... The idea that that gravity associated with the lost mass is also lost?

• 43:54Neil deGrasse Tyson?

  Oh, matter and energy are one and the same thing.

• 43:57Paul Mecurio?

  Mm-hmm.

• 43:57Neil deGrasse Tyson?

  So they each distort the fabric of space and time. And that's all you need to know about it.

• 44:03Paul Mecurio?

  Okay.

• 44:03Neil deGrasse Tyson?

  Mm-hmm. We will commonly think of matter discarding space, but if there's energy there, it will distort space as well. And equals mc squared reminds us that they're two sides of the same coin.

• 44:14Paul Mecurio?

  The, the more the amount of energy is created is, is the same amount of gravity lost? In other words, like, the mass lost is, gravity associated with the lost mass is also lost. Do you lose more gravity the more energy that's created?

• 44:27Neil deGrasse Tyson?

  If it leaves the system, yes, you're losing, you're losing gravity anytime any matter or energy leaves the system.

• 44:32Paul Mecurio?

  No, I know, but doesn't it sort of all change over time? You know, depending on the amount of energy that's created? The more energy that's created, the more gravity is lost? No?

• 44:43Neil deGrasse Tyson?

  Yes. But, the, it's a lot of energy and a very small amount of mass, so I wouldn't lose sleep over it.

• 44:50Paul Mecurio?

  Well, listen, it's up to me what I lose sleep over. Just because you walk through life not caring about science the way I do, I can't...

• 44:57Neil deGrasse Tyson?

  It is weird, though, that humans, for one-third of a rotation of the Earth, are semi-comatose.

• 45:06Neil deGrasse Tyson?

  One last question, I'll do it.

• 45:07Paul Mecurio?

  One last one? Quick one? Okay, okay, uh, Mc- Markler.

• 45:11Neil deGrasse Tyson?

  I used to have a bell here.

• 45:13Paul Mecurio?

  A Mark from Portland, Oregon. Is our solar system comprised of remnants from a single supernova or a collection of many? If many, I'm curious how, are, or any galaxy diffuses multiple supernovas together?

• 45:27Neil deGrasse Tyson?

  Okay, so first, a supernova is a huge explosion and its guts are just scattered everywhere. Just start with that. Then... The galaxy rotates, as we say, differentially. So the inner parts complete a circle faster than the outer parts. This shears the gas clouds that have all been contaminated by the detritus of a supernova explosion. And you get a few rotations of the galaxy, this stuff becomes very well mixed. And the next generation of stars is gonna have all the ingredients from that last round of supernova explosions.

• 46:05Paul Mecurio?

  It was like fertile ground for the next round.

• 46:07Neil deGrasse Tyson?

  Yeah.

• 46:08Paul Mecurio?

  Got it.

• 46:09Neil deGrasse Tyson?

  All the way through.

• 46:10Paul Mecurio?

  Alright, I think that's all our time.

• 46:12Neil deGrasse Tyson?

  These are good questions, wow.

• 46:12Paul Mecurio?

  Yeah.

• 46:13Neil deGrasse Tyson?

  Alright, we're done here. Yet another installment of Cosmic Queries with Paul Mecurio. Paul, we'll find you your show on the road?

• 46:21Paul Mecurio?

  Yeah, paulmccurio.com.

• 46:22Neil deGrasse Tyson?

  Did someone say, "Take that show on the road"? And then that's what you did?

• 46:25Paul Mecurio?

  I did it in New York, and then the authorities called and said, "Take it on the road." And Inside Out with Paul Mecurio, my podcast.

• 46:33Neil deGrasse Tyson?

  Isn't there a movie called Inside Out?

• 46:35Paul Mecurio?

  There is, but thanks for bringing that up. This is how you help me get people coming. Oh yeah, you just copied something, so don't go see it. Yeah, Inside Out with Paul Mecurio.

• 46:44Neil deGrasse Tyson?

  So it has good interactions with the audience. You're very good on your feet in that way.

• 46:47Paul Mecurio?

  Yeah, my show Permission to Speak is about sort of engaging the audience in their stories. It was born out of crowd work with an audience.

• 46:53Neil deGrasse Tyson?

  Yeah, good, love crowd audiences.

• 46:56Paul Mecurio?

  But it's, but people have fascinating...

• 46:57Neil deGrasse Tyson?

  And your podcast?

• 46:58Paul Mecurio?

  Inside Out with Paul Mecurio.

• 47:00Neil deGrasse Tyson?

  Which I've been on.

• 47:00Paul Mecurio?

  Yes, you've been on, and Paul McCartney, and Stephen Colbert, and a lot of fun people, so.

• 47:05Neil deGrasse Tyson?

  Well, I wasn't enough to...

• 47:07Paul Mecurio?

  You were. The only reason Paul McCartney did it is because he found out you did it.

• 47:12Neil deGrasse Tyson?

  Oh, see, that's what I expect.

• 47:16Paul Mecurio?

  And he knows a lot more about the theory of relativity than you do. Weird, I don't know, because I just thought he played music. No, yeah, so hopefully people can check all that stuff out. PaulMcCurio.com.

• 47:26Neil deGrasse Tyson?

  You got it. Alright, this has been StarTalk Cosmic Queries, Grab Bag Edition. Neil deGrasse Tyson here, thanking Paul Mecurio. As always, I bid you to keep looking up.