Cosmic Queries – The Big Stretch

What is fire? How do gravitational waves ripple through space-time? Neil deGrasse Tyson and comedian Harrison Greenbaum answer grab bag questions about why supernovae form black holes, photons, the singularity, and more!

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

• 0:01Neil deGrasse Tyson?

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

• 0:14Neil deGrasse Tyson?

  This is StarTalk. Neil deGrasse Tyson here, your personal astrophysicist. We're doing cosmic queries today. Grab bag. Oh, yeah. And I look to my left. I don't see Chuck Nice. Chuck, what did you do?

• 0:30Harrison Greenbaum?

  We look a little different.

• 0:32Neil deGrasse Tyson?

  Harrison Greenbaum, welcome back to StarTalk.

• 0:35Harrison Greenbaum?

  Yes, it's so nice to be here. Thank you for having me.

• 0:37Neil deGrasse Tyson?

  Yeah, last time it was B.C. before COVID.

• 0:41Harrison Greenbaum?

  That's right.

• 0:41Neil deGrasse Tyson?

  Which made it appearance.

• 0:43Harrison Greenbaum?

  We had a whole pandemic in between.

• 0:44Neil deGrasse Tyson?

  A whole pandemic in between. And also you had like a Las Vegas residency in there.

• 0:49Harrison Greenbaum?

  Yeah, I went across the country and back at that time.

• 0:52Neil deGrasse Tyson?

  And back. So just congratulations on where your talents have taken you.

• 0:56Harrison Greenbaum?

  Thank you.

• 0:56Neil deGrasse Tyson?

  And now you're right here in my office at the American Museum of Natural History.

• 1:00Harrison Greenbaum?

  As much going on here as the circus, I will say.

• 1:03Neil deGrasse Tyson?

  No, well, the universe is a circus unto itself.

• 1:06Harrison Greenbaum?

  Absolutely.

• 1:06Neil deGrasse Tyson?

  And it's many more than three rings going on there. Yes. Saturn's got rings. Multiple ring circus in the cosmos. So this is a grab bag.

• 1:16Harrison Greenbaum?

  Fantastic.

• 1:16Neil deGrasse Tyson?

  You've got the questions. I haven't seen them. And because it's a grab bag, it's a grab bag without an expert that we bring in. So I'm your expert.

• 1:26Harrison Greenbaum?

  Fantastic.

• 1:27Neil deGrasse Tyson?

  I'll do my best. If I don't know an answer, I'll just say, I don't know. Okay?

• 1:31Harrison Greenbaum?

  Okay.

• 1:32Neil deGrasse Tyson?

  But you have to.

• 1:32Harrison Greenbaum?

  We have Siri.

• 1:35Harrison Greenbaum?

  We do have, we have tools at our disposal.

• 1:39Neil deGrasse Tyson?

  You've got, the ways to bail me out is what you're saying? Okay.

• 1:43Harrison Greenbaum?

  If we don't know, it might be known.

• 1:45Neil deGrasse Tyson?

  Okay. All right. So what do you have first?

• 1:48Harrison Greenbaum?

  All right. So we have Lena McGrath. She writes, hello, Neil. I am Lena from Orlando. Where do photons come from? For instance, are they already inside my birthday candles? Or are they created from the fire?

• 2:01Neil deGrasse Tyson?

  Oh, I love that.

• 2:02Harrison Greenbaum?

  Does not specify what birthday she is on.

• 2:04Neil deGrasse Tyson?

  Does not. Okay.

• 2:05Harrison Greenbaum?

  Does not.

• 2:06Neil deGrasse Tyson?

  But the fact that she still uses candles?

• 2:08Harrison Greenbaum?

  Yeah.

• 2:09Neil deGrasse Tyson?

  What age would you say you stopped using candles?

• 2:11Harrison Greenbaum?

  Once the cake is too full.

• 2:12Neil deGrasse Tyson?

  Yeah, I think I stopped at 30.

• 2:15Harrison Greenbaum?

  Oh, wow. That's longer than I lasted.

• 2:17Neil deGrasse Tyson?

  I made it, I made it high in there.

• 2:18Harrison Greenbaum?

  I think after high school, I was candle free.

• 2:22Neil deGrasse Tyson?

  So it's a great question. It's reminiscent of a famous essay from the 19th century written by Michael Faraday. And it's called, what is fire? Ooh. Because what is it? It's an emoji I use too often. Oh, okay, I've seen the emoji. Can you touch it? Can you grab it? Can you hold it? Not really. So what is it? So there's a famous essay from the, from the 19th century. So a photon is a packet of energy, a pure energy. And it moves at the speed of light. It's the only thing it knows how to do, is move at the speed of light. And so if, by the way, energy can manifest in a dozen, many different ways. Okay?

• 3:06Neil deGrasse Tyson?

  You can have potential energy. Now, why is it that you can harm yourself by jumping out of a window? Okay? There's, there's a reason for it. Okay. When you hit the ground, energy killed you. I thought it was the sidewalk.

• 3:22Neil deGrasse Tyson?

  Okay. You had energy in your body. Yeah. While you were falling. One Red Bull, right before the show. And that, oh, yes. And the energy kept accumulating as you fell faster and faster. Right. Then you hit the sidewalk. All the energy that was in you, from your motion, kinetic energy, goes back into you as mechanical energy. And the only way your body can accommodate mechanical energy is to break stuff. Because it takes energy to break your bones. Sure. Energy can manifest in different ways. And the higher you take the elevator before you jump out the window, the more energy you have to break your bones upon hitting the sidewalk.

• 4:04Neil deGrasse Tyson?

  That's why jumps from higher altitudes will do more damage than from lower altitude. But if you're watching this and thinking about it, don't do it. Do not try this at home. Don't do it. Now, above a certain height, there's an air resistance. You hit what's called a terminal velocity, where the air is absorbing away some of that energy. And I am about to terminate. Be terminated. Terminal velocity to be terminated. So there are other ways that energy can be stored, like inside of an atom. And an electron can sit in many different energy levels. The atom has energy levels within it. It's not a continuous placement of energies. If there's an electron at a higher energy level, and something happens to make it drop to a lower energy level, it just lost energy.

• 4:50Neil deGrasse Tyson?

  Where did it go? Actually, it can go in one of two places. If another atom hits it, some of the energy of that electron can go to the kinetic energy of the other atom as it careens off. Oh, this happens a lot. So it's a kinetic energy.

• 5:05Harrison Greenbaum?

  A mugging.

• 5:06Neil deGrasse Tyson?

  A flyby looting of its energy. All right. So, but occasionally it just sort of jostles it. The electron deexcites, goes to a lower energy level. Where does that energy go? Bada bing, a photon is released from the atom of exactly the same energy as the difference between the energy levels of the electron. All the energy is accounted for. And so, and the photon goes in a random direction at the speed of light. That's where photons come from. They come from ways that used to be energy in an atom or some, or the vibrations of atoms and molecules and other particles.

• 5:50Neil deGrasse Tyson?

  And in those vibrations, it can lose energy by releasing a photon. And that's, that's what's going on. And it happens in all kinds of ways. If you have an electric stove and you turn it on and eventually it glows.

• 6:04Harrison Greenbaum?

  It was like blue, orange, it was a different color.

• 6:06Neil deGrasse Tyson?

  I hope your stove doesn't glow blue.

• 6:08Harrison Greenbaum?

  You can tell by the way how much I cook by my inability to answer this question.

• 6:12Neil deGrasse Tyson?

  You have no idea what a stove is. You have no idea what, you were right astrophysically, but in a kitchen, you're completely wrong. So the hottest your stove is going to get is red hot.

• 6:23Harrison Greenbaum?

  Gotcha.

• 6:24Neil deGrasse Tyson?

  But if you could, if you had an infinite knob, it will go, it would go a white hot and eventually blue hot.

• 6:30Harrison Greenbaum?

  Doesn't mean my band name. If I ever form a band, Infinite Knob.

• 6:33Neil deGrasse Tyson?

  Oh, Infinite Knob.

• 6:34Harrison Greenbaum?

  Blue hot's better.

• 6:36Neil deGrasse Tyson?

  But one of those, pick one, I'm good with you. I'll come see you.

• 6:38Harrison Greenbaum?

  Okay, great.

• 6:39Neil deGrasse Tyson?

  So the fact that the stove is glowing red is emitting light. Red light. So you have vibrating. Particles in the heating element of the stove and those vibrations will actually release light and and that in a way is cooling the stove except you keep pumping energy into the stove.

• 6:59Harrison Greenbaum?

  Right.

• 6:59Neil deGrasse Tyson?

  But if you turn off the stove, it's still glowing red, but then it sort of fades away. Why? Because it's giving up all its energy without it being replaced. And if it's hot but not glowing red, it's still giving off photons, but not red photons. If it's hot, what do you generally, what is that? Do you remember?

• 7:18Harrison Greenbaum?

  Don't touch it.

• 7:19Neil deGrasse Tyson?

  No, still don't touch it.

• 7:21Harrison Greenbaum?

  Yeah.

• 7:21Neil deGrasse Tyson?

  Until it's cool. So it would actually, if you put on infrared goggles, it would be glowing in the infrared. That's still a form of light, you know, infrared photons. So all these ways will generate photons and stars are doing it every moment of their lives and photons are crisscrossing through the universe and it'll continue that way until the last star dies.

• 7:44Harrison Greenbaum?

  So what does that have to do with birthday candles?

• 7:47Neil deGrasse Tyson?

  Oh, very good. Thank you for bringing it back on point.

• 7:52Harrison Greenbaum?

  I feel like Lena is at home right now. She's celebrating her birthday. The candles already melted down. It's ruined the cake.

• 7:57Neil deGrasse Tyson?

  It's like, Neil, where's the answer? So you have to give energy to the candle from somewhere else, a lighter or a match, right? There's no free lunch here, right? The energy's got to come. So what that will do.

• 8:11Harrison Greenbaum?

  Free cake.

• 8:12Neil deGrasse Tyson?

  Okay, free cake. You will light the, the.

• 8:15Harrison Greenbaum?

  The wick.

• 8:16Neil deGrasse Tyson?

  You will light the wick of the candle, which is typically coated in wax because the candles are made of wax. So you ignite the wick that will use molten wax as a fuel source. There you have it. Now, why doesn't the whole candle burn up in one instant? Because the, the wick is drawing the molten wax in and if you have too much of the wax.

• 8:46Neil deGrasse Tyson?

  It'll put out the flame. You need just the right amount to feed it and keep it going. And candles are beautiful this way. Okay? If the candle gets sort of, you know, if you, if you, have you tried this? Who has candles anymore? But you have like a three inch candle, let's say, and it's got liquid there. If you sort of tip liquid towards the wick, you can extinguish the wick.

• 9:07Harrison Greenbaum?

  Right.

• 9:08Neil deGrasse Tyson?

  You say, well, why is that if it's using the wick to light? Have you ever questioned this?

• 9:12Harrison Greenbaum?

  I have a couple of scented candles. Uh, most of them smell like my apartment burning down when I fall asleep.

• 9:17Neil deGrasse Tyson?

  Why does the liquid wax put out the wick? When the wick needs the liquid wax to burn.

• 9:21Harrison Greenbaum?

  Right.

• 9:21Neil deGrasse Tyson?

  Because it's too much at a given time. It's too much. So the wick draws it at just the right amount. Then it could burn the little bitty drops that come in at the rate that you need. So the energy, the starter energy comes from the match or from a lighter. And you hit the wick. Now the wick simply burns the wax. And wax is one of the great things that kept us lit for centuries. Wax candles that, you know, 17th, 18th centuries. Uh, we didn't have light bulbs. So candles was a thing. Wax candles. So wax is a, is a fuel source.

• 10:02Neil deGrasse Tyson?

  By the way, if you get wax hot enough where it goes molten and you just keep heating it, it can burn without a wick.

• 10:10Harrison Greenbaum?

  What?

• 10:12Neil deGrasse Tyson?

  So this happened to me at home. I ignited the entire surface of the, of the liquid wax in the pot.

• 10:19Harrison Greenbaum?

  I thought you told the police it was an accident.

• 10:24Neil deGrasse Tyson?

  No, I used to make candles. Okay?

• 10:26Harrison Greenbaum?

  I'm just trying to picture this birthday party.

• 10:27Neil deGrasse Tyson?

  No, no, no, I used to make candles. So you melt the candles and you can dip. What happens? You dip a wick in. So it gets wet with, with, um, wet wax. You put it in the air, air, room temperature air will cool the wax. And then it's a skinny candle. You dip it again and it keeps building layers and layers until there's the thickness you want. Okay. That's one way to make it. That's as you make a dip candle. Normally just pour it into a, into a mold. Okay. So I melted this pot. I had all these candle shards, right? And you put them all in there. You pull out the dead wicks. And now I have, I have, I have liquid candle wax. And I left them on the stove too long.

• 11:10Neil deGrasse Tyson?

  It ignited. You can't put water on it.

• 11:14Harrison Greenbaum?

  Oh, no.

• 11:16Neil deGrasse Tyson?

  It is hotter than boiling water. So if you put water in there, the water will be heated, start to boil, and then it'll boil fragments of flaming wax out of the, out of the, so there's only one way to put out that fire.

• 11:34Harrison Greenbaum?

  Throw it out the window.

• 11:38Harrison Greenbaum?

  Hope it's potential energy.

• 11:40Neil deGrasse Tyson?

  Yeah. Now you're gonna give it extra potential energy. So, or kinetic energy. So, no, you gotta take a lid and cover it and that'll smother it.

• 11:47Harrison Greenbaum?

  That's a less exciting answer.

• 11:48Neil deGrasse Tyson?

  It's totally less exciting, but I knew enough.

• 11:50Harrison Greenbaum?

  Suffocate it.

• 11:51Neil deGrasse Tyson?

  I knew enough about, yeah, you're suffocating it. I knew enough about thermodynamics that that's how you do that. So, the candle doesn't all burn at once because it can only burn a little bit at a time and it burns its way down. And there you have it.

• 12:02Harrison Greenbaum?

  Nice. Well, happy birthday, Lena.

• 12:04Neil deGrasse Tyson?

  Yeah, however old you are.

• 12:19Speaker 02

  Hi, I'm Ernie Carducci from Columbus, Ohio. I'm here with my son Ernie because we listen to StarTalk every night and support StarTalk on Patreon.

• 12:29Neil deGrasse Tyson?

  This is StarTalk with Neil deGrasse Tyson.

• 12:43Neil deGrasse Tyson?

  Oh, by the way, these are all our Patreon supporters. These are, they pay.

• 12:47Harrison Greenbaum?

  Amazing.

• 12:47Neil deGrasse Tyson?

  So you get to ask questions as a Patreon supporter at our entry level amount, which is like $5 a month. So go for it.

• 12:55Harrison Greenbaum?

  All right. So we have Alan Rayer. He wrote, hello, everyone. Waving emoji, cowboy emoji. It's Alan from Lithuania. A lot of cowboys there. Always wondered about gravitational waves. Please explain how and what did they actually detect in 2015?

• 13:10Neil deGrasse Tyson?

  Oh, very nice. Yeah. So that's the first detection of gravitational waves was then?

• 13:15Harrison Greenbaum?

  Nice.

• 13:16Neil deGrasse Tyson?

  Interestingly.

• 13:18Neil deGrasse Tyson?

  It was the centennial, the near centennial, I think the prediction came out in 1916, but basically the centennial of Einstein's prediction that such a thing even exists. So it took a century to verify that what he predicted was correct. So just to put that in context. All right. So the way this works is, according to Einstein's general theory of relativity, you're here and we say you have a gravitational force. I don't know if you knew that, but you do, right? I like it. And the more mass you have, the more is your gravitational force. I've had an increasing amount of gravitational force over the last few years. Is that right? Okay. So it'll go up according to your mass.

• 14:03Neil deGrasse Tyson?

  And we can measure that, more importantly. If you move through space and time, then your gravitational field needs to respond to that in some way. Because it used to be over here and now you're over there. Newton described gravity as just a force at a distance. Okay? Action at a distance. But he was still mystified. How could it gap the vacuum of space? What's going on? How do we know each other? How do we know about what? Why do we know? Why? He knew his equations worked, so he went with it, but... That's some confidence. It's still... He's like, "I know these are right. I can't prove it, but I am 100% sure." I can't demonstrate it.

• 14:48Neil deGrasse Tyson?

  What's going on in the mystery of the vacuum of space? But it's working, so... Exhibit A. Trust me. Trust me. So it's working. And Einstein said, "Gravity is not so much action at a distance. Gravity is a disturbance in the fabric of space and time."

• 15:11Neil deGrasse Tyson?

  So disturbance is too violent. It is a shape of the fabric of space and time made by the existence of matter and energy wherever you might find it. Let's take a black hole, for example. A black hole is such a distortion of space and time that light cannot even escape. That's why we call it black. And you can't come out, it's a whole black hole. Best named thing there ever was, ever. So if you're just somebody wandering by a black hole, you'll feel your trajectory altered by it. Newton would say that's action at a distance. Einstein would say that is the shape of curved spacetime.

• 15:56Neil deGrasse Tyson?

  And you're just following where space and time wants to bring you. It's like in NASCAR, are they actually turning left? No, because the track is banked. The bank turns them forth, turns the car.

• 16:11Harrison Greenbaum?

  I feel like the drivers would have, would be very upset by this. Like, what are we, what are we training for?

• 16:16Neil deGrasse Tyson?

  Yeah, so their steering is primarily maneuvering in the traffic rather than making a left turn as they go around the track. So the track is shaping their path in the same way space and time will shape the path of anything moving, but light is the best tracer of this. What happens when two black holes collide? OMG. Black holes collide, they are already a disturbance in the spacetime continuum. Now they come together, it is such a disturbance that they will create a ripple in the fabric of space and time emanating at the speed of light.

• 16:58Neil deGrasse Tyson?

  A ripple, because as they come closer and closer, they, they spiral and faster and faster, and then they come together and right at that instant, poof, there's a ripple. The first of these that was discovered had been traveling for 3 billion years. How do you detect it? We need special equipment. We call it LIGO, Laser Interferometer Gravitational Wave Observatory, sensibly abbreviated, LIGO. So they have two, I forgot how long they were, kilometer long tunnels. Evacuated, no air. They have lasers that simultaneously go up the tunnel and back

• 17:39Neil deGrasse Tyson?

  from a mirror that's at the other end. These two laser beams know about each other. They are coherent. They march to the beat of the same drummer when emitted. If on the up and back trip, something happened to the fabric of spacetime, then one of those paths will be slightly different from the other, slightly longer or slightly shorter. And then the waves will no longer match up. And you can conclude that something happened here that didn't happen there. They're at right angles to each other. So this wave, this gravitational wave, as it washes over the observatory, depending on which angle was oriented relative

• 18:23Neil deGrasse Tyson?

  to the wave, they will stretch or expand by different amounts from each other. And they measure this. They measured it. They knew what two colliding black holes should look like in the experiment, matched up. The announcement gets made, Nobel Prize is awarded. Now, just for context.

• 18:42Harrison Greenbaum?

  You said with a ton of voice that they were, it was later discovered that it was wrong.

• 18:46Neil deGrasse Tyson?

  No, no, no. I have a follow on to that.

• 18:49Harrison Greenbaum?

  2017, they took it back. Turns out one of them just jostled the machine a little bit.

• 18:54Neil deGrasse Tyson?

  No, they only discovered it in 2015. Nobel Prize is later.

• 18:57Harrison Greenbaum?

  Gotcha.

• 18:57Neil deGrasse Tyson?

  Okay, all right. So, many people don't know that Einstein wrote down the first equations that enabled the laser to be invented later on. This is crumbs on his plate.

• 19:08Harrison Greenbaum?

  Right.

• 19:09Neil deGrasse Tyson?

  Okay. When you're that brilliant, crumbs do great things because you're focusing on the main events, like the theory of relativity and other things.

• 19:18Harrison Greenbaum?

  The back page of his notebook just said tunnel laser.

• 19:20Neil deGrasse Tyson?

  So Einstein invents a new theory of the universe, the general theory of relativity, that predicts the existence of gravitational waves. Shortly after that, he writes down the equation that permits the invention of the laser.

• 19:38Neil deGrasse Tyson?

  Decades later, people invent the laser. Decades after that, they use the laser to measure and discover the existence of gravitational waves.

• 19:48Harrison Greenbaum?

  And entertain cats.

• 19:50Neil deGrasse Tyson?

  Yes. Einstein's a badass.

• 19:54Harrison Greenbaum?

  Hundred percent.

• 19:55Neil deGrasse Tyson?

  People getting Nobel prizes off of crumbs that fell off his plate. He should have had eight Nobel prizes.

• 20:00Harrison Greenbaum?

  Right. Did he get one?

• 20:02Neil deGrasse Tyson?

  Yeah, he got one.

• 20:02Harrison Greenbaum?

  All right. Okay. Okay. Good.

• 20:03Neil deGrasse Tyson?

  He got one. But for other stuff, I mean, not for his greatest work. For really important work, but not his greatest work. He demonstrated that atoms actually exist. That's pretty good.

• 20:13Harrison Greenbaum?

  That's the other, I would say.

• 20:17Neil deGrasse Tyson?

  And he demonstrated that light comes in discreet packets called photons.

• 20:24Harrison Greenbaum?

  Which we just talked about.

• 20:25Neil deGrasse Tyson?

  We just talked about. So that's good.

• 20:28Harrison Greenbaum?

  That's pretty good.

• 20:30Neil deGrasse Tyson?

  In a lifetime, you did good. But you did that and then just kept going.

• 20:33Harrison Greenbaum?

  Yeah, but at the same time, I was learning magic and you were nearly burning your house down. The biggest wax candle.

• 20:40Neil deGrasse Tyson?

  That's the backstory. And the lead scientist on this was Kip Thorne.

• 20:45Harrison Greenbaum?

  Yeah.

• 20:46Neil deGrasse Tyson?

  Kip Thorne. People who read movie credits will recognize Kip Thorne as one of the co-executive producers of the film Interstellar.

• 20:54Harrison Greenbaum?

  Nice.

• 20:54Neil deGrasse Tyson?

  That's how you knew if there's going to be any black holes in it, they're going to get it right.

• 20:59Harrison Greenbaum?

  Yes.

• 20:59Neil deGrasse Tyson?

  Okay. You don't have to double check that one. He's got it. Yeah.

• 21:03Harrison Greenbaum?

  I love that.

• 21:03Neil deGrasse Tyson?

  All right. Give me some more.

• 21:04Harrison Greenbaum?

  All right. Well, you were talking about the fabric of space. So it makes sense to bring this question up because Matt D. wrote, greetings, Dr. Tyson. I'm Matt from Oklahoma and have a question about the fabric of space. In all caps, what is it? You tear it like cloth fiber and sew it back together? Take it easy, Matt.

• 21:20Neil deGrasse Tyson?

  Okay. All right. So he has issues with the word fabric.

• 21:25Harrison Greenbaum?

  Maybe. It sounds like he thinks it is a fabric.

• 21:28Neil deGrasse Tyson?

  Well, it does stretch. Like our style, right? So the universe stretches, but we don't know how much longer it will continue to stretch.

• 21:38Harrison Greenbaum?

  Oh, it's like my pants eventually it snaps. Been there, done that.

• 21:43Neil deGrasse Tyson?

  I think we did a whole episode or a whole section of an episode on the future of the universe. One of the possible futures is it will expand so rapidly that the fabric of the universe cannot keep up with it and it will rip. And it's called the big rip. And I'm terrified, I'm terrified by this because I, I finally grew accustomed to the stretching of space and time, whatever even that means, right? Now you're gonna tell me it's stretching and it's gonna rip? Oh my gosh, so. Do you know where it's gonna rip? Are we near the rip site? Do we need to move a little? Put some, some pre-stitches in it to keep it going? No, it was, it would rip at its very core.

• 22:28Neil deGrasse Tyson?

  All places within the fabric would just disassemble. Rip and fabric go together as two words, but before we use the word rip and the fabric, we spoke of space as a rubber sheet that stretches and maybe it can stretch forever. Like, we don't know. We just don't know. So now the specifics of the question was what? It just said, what is it? What is the fabric? All we can say is space behaves as though it is a stretchy substance. Pick any word you want to give it. Right. Maybe we should have called the Lycra of the universe. The Neoprene. The Neoprene, right.

• 23:13Neil deGrasse Tyson?

  I, I don't know, call, call it anything, but we try to find an analogy that can make it more understandable to you, to anyone, to ourselves. So fabric of the universe, it seems to fit the bill very well, right on up to the rip. Right. So, so that's why, and, and. And that's when everything in the universe disassembles, including us? Oh, you're, aren't you, you're made of things in the universe, so yeah. I was trying to be optimistic. Yeah, all the, the electrons, protons, and neutrons, they're not all gonna break apart, but you'll be intact, okay? Exactly. That'll be. Do I feel it? Yeah, I'm, I'm terrified by it. If it happens at all, it'll happen in 22 billion years.

• 23:58Neil deGrasse Tyson?

  Oh, so we're, okay, we're okay. No, I got it on my, on my calendar. So fabric is, is metaphor, but it's a very apt metaphor for what the universe is, because the universe can curve, incur back on itself, it can stretch. If you're not happy with fabric, come up with another term, but I think we're good.

• 24:18Harrison Greenbaum?

  That's pretty good.

• 24:18Neil deGrasse Tyson?

  All right.

• 24:19Harrison Greenbaum?

  All right. This question comes from Geezer Windbag. "Greetings, Dr. Tyson. I'm curious why we say the universe exploded in the Big Bang. It seems to me more likely that the singularity expanded and fragmented, and the universe we see is still all within the singularity. An observer outside the original singularity would still see a singularity, though from our perspective, the universe is incredibly huge. Thoughts?"

• 24:42Neil deGrasse Tyson?

  Okay, so a couple of things. The, if you don't like the word explosion, I'm okay with that, because the singularity that birthed the universe was the rapid stretching of spacetime.

• 24:53Harrison Greenbaum?

  There we go.

• 24:55Neil deGrasse Tyson?

  See what I did there? So the rapid stretching, you can say, was there an explosion? You know what an explosion is? It is a rapidly moving shockwave within a medium. That's what blows out windows and blows down doors. It's a shockwave moving through the air. Well, the Big Bang is not a thing moving through something else. It is the expansion of space and time. So it's more accurate to say it's the big stretch rather than the Big Bang. The Big Bang was used pejoratively by, now going back 70 years, by an opponent of the Big Bang who couldn't imagine the universe would begin this way. He wanted

• 25:38Neil deGrasse Tyson?

  the universe to be in a steady state at all times, and he's, so he used the term Big Bang as an insult to the ideas that people were having.

• 25:48Harrison Greenbaum?

  He came in and said, you know what? This theory is a big stretch. I'm like, you have no idea how right you are. You have, that's exactly right.

• 25:54Neil deGrasse Tyson?

  This is a stretch. That's it. So, yeah, it's metaphor, but we're good with it.

• 25:59Harrison Greenbaum?

  All right, cool. Well, thank you, Geezer Windbag.

• 26:01Neil deGrasse Tyson?

  No, no, but he asked something else about it.

• 26:02Harrison Greenbaum?

  Well, he said, is it more likely that the singularity expanded and fragmented, and the universe we see is still all within the singularity?

• 26:09Neil deGrasse Tyson?

  We are no longer the singularity, so anyone observing us will not say they look like a singularity. The interesting question is, if you look at the math of our universe out to the horizon...

• 26:23Neil deGrasse Tyson?

  The density of matter within it, the size of the horizon, if you run the math, we have all the same properties of an authentic black hole. And black holes have singularities in their center. So are we some mondo black hole? Is there a point where the similarities end? We don't know.

• 26:43Harrison Greenbaum?

  We could all be in a black hole?

• 26:44Neil deGrasse Tyson?

  Yes, yes, yes. I have a book on my shelf that describes the new spacetime that opens up after you fall into a black hole. Time changes for you, takes more slowly relative to everybody outside the black hole. So as you fall in, you will see the entire future history of the universe unfold before your very eyes and a new spacetime continuum open up.

• 27:09Harrison Greenbaum?

  That sounds awesome. Mine is the being ripped apart.

• 27:14Neil deGrasse Tyson?

  Mine is the being ripped apart part. Yeah. So if the black hole is big enough, the tidal forces won't rip you apart. You can survive the fall.

• 27:22Harrison Greenbaum?

  Oh, that's cool.

• 27:23Neil deGrasse Tyson?

  Yeah, yeah, yeah, it's good.

• 27:24Harrison Greenbaum?

  It kind of feels like a way to go.

• 27:25Neil deGrasse Tyson?

  Like if I totally want to go that way. You know, rather get hit by a bus or laid up in the hospital. Launch me into a black hole. I'll give all my reports until I can't. Yeah.

• 27:37Harrison Greenbaum?

  All right, so we have Eliyzer Vega. Hello, Dr. Tyson, this is Eliyzer from Puerto Rico.

• 27:42Neil deGrasse Tyson?

  Puerto Rico.

• 27:43Harrison Greenbaum?

  I love that place.

• 27:43Neil deGrasse Tyson?

  Is that your best way you could pronounce it?

• 27:45Harrison Greenbaum?

  Puerto Rico.

• 27:46Neil deGrasse Tyson?

  All right. Give you a B plus.

• 27:48Harrison Greenbaum?

  All right.

• 27:49Neil deGrasse Tyson?

  Puerto Rico.

• 27:50Harrison Greenbaum?

  I have a last gap to fill with gravity. If gravity is the effect of the mass bending space, then why, when a star goes supernova, space still bent for a black hole to form instead of immediately unbending? It is as matter is blown apart. Or better said, what makes space remember what was there before? So when it blows and matter is dispersed, space won't recover back, but stay bent as a black hole. Did you get all of that?

• 28:13Neil deGrasse Tyson?

  Wow. Stars above a certain mass, when they die, will go as supernova and they'll leave behind a neutron star. Stars of even higher mass, we're not entirely certain of the boundary of this, but stars of a higher mass can go supernova and make a black hole. Stars of even higher mass, the supernova never gets out. Black hole all the way. So only in that last case is all the mass of the entire system part of the black hole. And the spacetime curvature at the end was the same as it was in the beginning. Whereas the one where some gets blown out and others become a black hole? Yeah, that black hole does not have the full gravity that the whole system had before

• 28:57Neil deGrasse Tyson?

  because half of it got blown away. It's that simple. So he's right to think about this, but the answer is not that deep.

• 29:04Harrison Greenbaum?

  That's pretty good.

• 29:05Neil deGrasse Tyson?

  Okay.

• 29:06Harrison Greenbaum?

  Matthew Jury wrote, hello, everyone. How can a gravitational singularity exist if infinite curvature means infinite time?

• 29:14Neil deGrasse Tyson?

  We do not have a good way to talk about the singularity.

• 29:18Harrison Greenbaum?

  Would you say the jury is out?

• 29:21Neil deGrasse Tyson?

  What I would say is that's why we have string theorists. To bridge the gap between quantum physics and general relativity. One, the theory of the small, the other, the theory of the large. But at the beginning of the universe, the large was small. Whole universes were operating in the quantum realm. And...

• 29:39Harrison Greenbaum?

  I've seen Ant-Man, I get it.

• 29:40Neil deGrasse Tyson?

  Yeah, yeah, there you go. Okay. So if that's the case, what's happening at the singularity? Because you don't get singularities in quantum physics, you get it in general relativity. So that's where it's been said, the singularity is where God divides by zero. Have you divided by zero lately?

• 30:00Harrison Greenbaum?

  Error.

• 30:00Neil deGrasse Tyson?

  Yes, yes.

• 30:01Harrison Greenbaum?

  Yes.

• 30:02Neil deGrasse Tyson?

  Error.

• 30:03Harrison Greenbaum?

  I do a magic trick where I have people put stuff into a calculator. And if they divide by zero, there's no magic trick because there's just an error. So I very much, it's very silent for me.

• 30:13Neil deGrasse Tyson?

  Wow, okay.

• 30:14Harrison Greenbaum?

  To avoid the divide by zero.

• 30:16Neil deGrasse Tyson?

  If you divide by zero, it's an error, it's undefined. We don't know what to do there. Yet we know these two theories work in their own realm. Their own regimes, the small and the large. You bring them together, the shotgun wedding, that won't necessarily work as you had planned. So we got top people working on it. But no, we can't tell you what's happening inside the singularity.

• 30:36Harrison Greenbaum?

  All right.

• 30:36Neil deGrasse Tyson?

  Remains a mystery, yes.

• 30:57Harrison Greenbaum?

  Yogesh Jogh wrote, hello to my personal astrophysicist. If someone keeps traveling back and forth at Planck length distance, does it mean that it's traveling eternally?

• 31:09Harrison Greenbaum?

  He did put a parenthetical, it says, "An idea slash attempt to say that the particles don't come in and out of existence, they're just traveling eternally at Planck length distances, and four forces hits them at the right time to let them exist in this universe."

• 31:24Neil deGrasse Tyson?

  Yeah, I, that, I don't know what he's talking about. I can tell you this, a Planck length is the smallest unit of length that we can measure. It's very, very small. It almost doesn't make sense.

• 31:37Harrison Greenbaum?

  It's not the size, it's what you do with it.

• 31:42Neil deGrasse Tyson?

  It turns out in quantum physics, everything is in motion. Everything vibrates at all times.

• 31:50Harrison Greenbaum?

  Exhausting.

• 31:51Neil deGrasse Tyson?

  To say you have something moving back and forth across a Planck length, all matter is doing that at all times. Because everything is always in motion. Always. So to say, let's do it at a Planck length, Planck length and its time at infinity, I don't know how the connecting Planck length and infinity time in that question. But everything is always in motion at all times. And it has nothing to do with measuring time at infinity.

• 32:23Harrison Greenbaum?

  Gotcha.

• 32:23Neil deGrasse Tyson?

  All right.

• 32:24Harrison Greenbaum?

  Especially in this city, huh? New York City? All right, I'm fired. Okay.

• 32:31Harrison Greenbaum?

  This is from Vinay Kashiap. He says, hello.

• 32:35Neil deGrasse Tyson?

  What was his first name?

• 32:36Harrison Greenbaum?

  Vinay?

• 32:37Neil deGrasse Tyson?

  Vinay, okay.

• 32:37Harrison Greenbaum?

  Vinay? It's how I would say Vinnie if I was being fancy.

• 32:40Neil deGrasse Tyson?

  Okay, okay, Vinay.

• 32:41Harrison Greenbaum?

  Vinay. He's, hello, this is Vinay from India. I was just wondering why black holes can't just be dark matter. There seems to be a lot of them, they are massive and seem to have more gravity. Most importantly, we can't see them.

• 32:54Neil deGrasse Tyson?

  Let's list the dark matter candidates. Would there be dark clouds? Could there be? Vagabond planets that are not illuminated by a host star that got ejected into the galaxy? Could it be black holes? It turns out, the physics of the early universe limits how much ordinary matter there can be. Black holes count as ordinary matter, because you make them from ordinary matter. It limits it. If there's a delicate set of knobs that we're turning in the early universe to understand what the universe was and what it became. And so, these knobs are fascinating, because some combinations of knobs don't work at

• 33:39Neil deGrasse Tyson?

  all. You don't get a universe, or you get a universe that's very different from what we have. So, the problem with dark matter is, it doesn't interact with ordinary matter in any way, other than by gravity. And so, if you look at what it does in the universe, during the early universe, it can't be regular matter, otherwise we'd have a universe completely different from what we have. And black holes are made of ordinary matter. It has to be something completely exotic, beyond the measurements we've made of electrons,

• 34:19Neil deGrasse Tyson?

  protons, neutrons, atoms, molecules, solids, biology, chemistry, physics, psychology, everything that we know and love, falls outside of what dark matter can be. So, let's say we have very good theoretical evidence, theoretical support for why dark matter can't be black holes.

• 34:37Harrison Greenbaum?

  We have Mike Mohammed Kakeh, I see it's pronounced as a birdwood. Greetings, Dr. Tyson. Mike Kakeh, from Berlin, Germany. While it's well-known that most of Earth's energy originates from the Sun, I'm curious about the source of tidal energy. Can it be traced back to the Sun? Or does it stem from a different origin? Is it possible that tidal energy has multiple sources?

• 34:58Neil deGrasse Tyson?

  I love that, because when we talk about green energy, we're talking about renewable energy. And if you could turn plants into gasoline, which we do with ethanol... Um, which is the one from corn?

• 35:11Harrison Greenbaum?

  My wife is from Nebraska, so she's gonna be very disappointed if I don't know the corned thing.

• 35:15Neil deGrasse Tyson?

  Kick your ass. Yeah, I think ethanol, we get that from corn.

• 35:18Harrison Greenbaum?

  Yes.

• 35:18Neil deGrasse Tyson?

  And corn is a renewable resource. All right, it's not fossil fuels where you take it out, you can't wait for new fossils to form. All right, that's not how that works. So that's why one is renewable and one isn't. By the way, do you know the original energy source of fossil fuels? The sun.

• 35:34Harrison Greenbaum?

  Oh, there you go.

• 35:35Neil deGrasse Tyson?

  Oh, you're gonna say dinosaurs? No, it's mostly plant life at the time, but where does plant get its energy?

• 35:41Harrison Greenbaum?

  From the sun.

• 35:42Neil deGrasse Tyson?

  The sun.

• 35:42Harrison Greenbaum?

  But it's incident.

• 35:43Neil deGrasse Tyson?

  So all fossil fuels is energy from sunlight. It's just not renewable because it's a one-time use. So all plants get their energy, all surface plants get their energy from the sun. You eat plants, you get energy from that. If you eat meat, you eat some animal that ate an animal or ate plants. And so that the tracking is back to the sun. Now, here's something deep. What generally do fish eat?

• 36:15Harrison Greenbaum?

  I was gonna say fish food. That was what came to my first.

• 36:19Neil deGrasse Tyson?

  Fish food, of course.

• 36:21Harrison Greenbaum?

  They eat, well, do they eat stuff in the ocean, algae and stuff?

• 36:25Neil deGrasse Tyson?

  Eat other fish.

• 36:26Harrison Greenbaum?

  Yeah, but then who eat?

• 36:28Neil deGrasse Tyson?

  Well, I'm getting there. Good one. Good one. This is, this is where I'm headed. Okay?

• 36:32Harrison Greenbaum?

  This is turtles all the way down.

• 36:33Neil deGrasse Tyson?

  That's all right now, but, but it can't go all the way down. This is why you can't, there's no such thing as a stable cannibal society. It's not stable.

• 36:46Harrison Greenbaum?

  Amongst other reasons.

• 36:48Neil deGrasse Tyson?

  I'm sorry. I'm not ranking the reasons. I'm just offering reasons. Because you can't just keep eating each other.

• 36:58Harrison Greenbaum?

  Right.

• 36:59Neil deGrasse Tyson?

  Because you will run out of people.

• 37:02Harrison Greenbaum?

  Sure.

• 37:03Neil deGrasse Tyson?

  But you can say, well, why don't we reproduce faster than we eat? That's not possible because if you're a fully nourished human being, you have to eat at least a whole other human being.

• 37:17Harrison Greenbaum?

  Right.

• 37:18Neil deGrasse Tyson?

  Because you are a human being, right? You have to eat at least that. And if you just run the numbers, you can, you can never have a stable thing. We're only eating other things that are being born within it. At some point, you need a source from the outside.

• 37:34Neil deGrasse Tyson?

  So the big fish eats the littler fish, eats the littler fish, eats the littler fish. This goes all the way down until you get to plankton. So the fish start eating all the way down.

• 37:44Harrison Greenbaum?

  Right.

• 37:44Neil deGrasse Tyson?

  And then you get to some point where if that's all that was happening, the ocean would just eat itself and there'd be no living things, no fishes left in the ocean. Something has to come in from the outside. Somebody's got to deliver the groceries.

• 37:58Harrison Greenbaum?

  SpongeBob.

• 38:02Harrison Greenbaum?

  He has a pineapple under the sea.

• 38:03Neil deGrasse Tyson?

  You got it, you got it. Um, his pineapple is actually in the sea.

• 38:08Harrison Greenbaum?

  Yeah, that's true.

• 38:11Harrison Greenbaum?

  We need to correct that.

• 38:12Neil deGrasse Tyson?

  Okay, I'm just saying, I don't mean to get all technical on SpongeBob, but you finally reach the level of plankton.

• 38:19Harrison Greenbaum?

  SpongeBob.

• 38:21Harrison Greenbaum?

  Nailed it.

• 38:22Neil deGrasse Tyson?

  And there are two categories of plankton, okay? One of them eats other life forms in the ocean. The other for nourishment. The other gets its energy from the sun. And they all live right at the surface where they can get sunlight. That is the base of the food chain of the ocean. The phytoplankton. If you kill them off, you will systematically render extinct every other fish in the ocean that eats other fish. Now, there might be some fish that eat like the kelp and seaweed and things. There might be some thing because, but where does kelp get its energy from? The sun.

• 39:03Harrison Greenbaum?

  Right.

• 39:04Neil deGrasse Tyson?

  Okay, so the sun is the ultimate source of all energy in the, in the typical fishes that we think of in the ocean. However, the ocean in certain parts is open to what's below it. What's below the ocean, well, you get through the crust and below the crust is, is the, is the mantle. And in the mantle is magma.

• 39:25Harrison Greenbaum?

  Beneath that Godzilla, according to the films.

• 39:27Neil deGrasse Tyson?

  Oh, is that right? Okay, I did not know that.

• 39:29Harrison Greenbaum?

  The hollow earth.

• 39:31Neil deGrasse Tyson?

  Yes.

• 39:33Neil deGrasse Tyson?

  Thank you for enriching this scientific discussion. So I keep thinking this should be magma PI. That would be a fun.

• 39:44Harrison Greenbaum?

  A really cool mustache. That is past the point of boiling.

• 39:48Neil deGrasse Tyson?

  So below the crust, we get the mantle and within the mantle is magma. Okay. Molten rock. Earth has retained still a considerable amount of heat from when it formed. And that heat wants to get out and it gets out through volcanoes, uh, crevasses in the, in the bottom of the ocean, the mid ocean ridge are just such a place. One of these ridges goes through Iceland, the country. Iceland is growing because the continental plates are separating magma gurgles up, hardens and is more Iceland.

• 40:24Harrison Greenbaum?

  That's a very good plan for the future.

• 40:26Neil deGrasse Tyson?

  We have discovered life forms that thrive on geochemical energy.

• 40:35Neil deGrasse Tyson?

  Enabled by these hot vents at the bottom of the ocean.

• 40:40Neil deGrasse Tyson?

  In apocalyptic earth, even if the sun burns out, if the sun, if someone plucked the sun out of the solar system and we fly off at a tangent into interstellar space, we will all die rapidly. But the life forms at the bottom of the ocean that are warm from the magma oozing up through the vents, they'll be just fine. They will survive the death of earth surface. So that's another source of energy. By the way, geothermal energy, because Iceland is sitting on a, on a, at the separation of two continental plates, they're almost entirely geothermally driven. Their carbon footprint is miniscule. They have so much energy, they send water under their streets.

• 41:28Neil deGrasse Tyson?

  So that it never gets icy in the winter. We don't need snowplows, just heat the streets.

• 41:35Harrison Greenbaum?

  Right.

• 41:35Neil deGrasse Tyson?

  So, so that's another source of, it's renewable in the sense that it's like a near infinite supply of earth energy available to us. All right. Yes, it would one day run out, but not really because we had something to do with it. All right. It's the volcanoes got, have you seen earth?

• 41:56Harrison Greenbaum?

  Yeah.

• 41:56Neil deGrasse Tyson?

  Get angry? All right. It's got a lot to kill us in the future. So that's another source of energy. So these are different ways. So another way is hydroelectric. Okay. So that's to be dams. You have water up here and that there is a certain height that it can fall, gaining kinetic energy.

• 42:16Harrison Greenbaum?

  Sure.

• 42:17Neil deGrasse Tyson?

  And it comes through a turbine that then drives a generator that makes electricity. So what's that based on? How did the water get up to the top of the dam? The sun evaporated it from the ocean, brought it up to a cloud. The cloud moved over the land, rained on the land. It brought the water up to the, up to the upper levels. That's solar power. Hydroelectric is solar power. How about wind? Why does air move horizontally on the earth? You know what Ogden Nash said? He said, "Wind is caused by trees waving their branches." And I thought that was good. Like, how would you know it wasn't that?

• 43:01Harrison Greenbaum?

  I feel like we do know that. I feel like we're about to lead into the fact that that can't be.

• 43:08Neil deGrasse Tyson?

  Yeah. It was just a, it's a clever, kind of fun, stupid observation.

• 43:12Harrison Greenbaum?

  The only thing I know about Nash is he had a great equilibrium.

• 43:15Neil deGrasse Tyson?

  Oh, that's the mathematician.

• 43:16Harrison Greenbaum?

  Different Nash.

• 43:17Neil deGrasse Tyson?

  That's a totally different Nash.

• 43:19Harrison Greenbaum?

  And then the founder of Nashville.

• 43:20Neil deGrasse Tyson?

  Oh, I don't know who that would be.

• 43:22Harrison Greenbaum?

  I assume he's a Nash.

• 43:24Neil deGrasse Tyson?

  So wind comes from the unequal heating of earth's surface that creates air that rises, air that falls, and that also creates pressure differences that'll move air horizontally as well as up and down. So wind energy is solar energy. Set up a solar panel. What do we call that energy? Solar. Solar. That's taking out the middleman and now you have solar power is solar energy. So all of these are solar power that is in principle renewable until the sun runs out of energy. All right. How about tides? Tides slosh back and forth. Love it. Well, we associate, commonly associate tides with the moon. Sure. So the moon tides have nothing to do with the sun.

• 44:08Neil deGrasse Tyson?

  So if you have a tidal thing that drifts with it and generates energy, it's also renewable because you're always going to have tides, but it's not traceable to the sun. However, one third of the tides you measure comes from the sun. How's it doing that? Well, the full name is loony solar tides. Loony moon, solar sun, loony solar tides. The tides we all experience are loony solar tides. And the moon is like two thirds of it and the sun is one third at all times, at all times. If you're using tides, some of that is the sun. Most of it is the moon. And so there you have it. That's the difference from all of this. But if you pull fossils out of the ground, you're not renewing that.

• 44:53Neil deGrasse Tyson?

  And when you run out of fossils, you're done. Oh, by the way, there's thermonuclear fusion. We haven't harnessed it yet. We know how to create it. They're called bombs, but when you harness it. That's a lot of energy. That's a lot of energy. You can create a power plant and that's fusing hydrogen together to make helium. The sun does that every day. So we just be mimicking the sun on earth. It's the nuclear fission that has dirty byproducts. And that's what the original atom bombs were made of, fission bombs. But nuclear fusion, that's the holy grail. But here's, I saw a bumper sticker once that said, no nukes. It was a very green, sort of progressive, left-leaning bumper sticker, no nukes.

• 45:37Neil deGrasse Tyson?

  But the O in the no was a sun.

• 45:41Harrison Greenbaum?

  Which is the ultimate nuclear weapon.

• 45:43Neil deGrasse Tyson?

  The ultimate nuclear furnace is the sun. Okay, if you had no nukes, you wouldn't be here. All right, well, you know what they mean, of course. They don't want like nuclear energy. They want solar energy, but solar energy is nuclear. I think at the time I saw this bumper sticker was still in the Cold War. So maybe they were talking about the nuclear arsenals.

• 46:02Harrison Greenbaum?

  Sure, sure.

• 46:03Neil deGrasse Tyson?

  But the fact that they had a sun there, it still tells me that they were thinking of generating power.

• 46:09Harrison Greenbaum?

  Sure.

• 46:10Neil deGrasse Tyson?

  Yeah, use solar power rather than nuclear power. But one other quick source of energy, because the big problem with solar energy is how do you store it? If you want to use it at night, how do you use solar energy? Now, you can't. Okay, tides still move in and out at night. That works. Hydroelectric, you can use that at night. That all still works, but how do you use solar panels? So there's talk now of using solar panels to lift heavy weights up a hillside to turn photons into potential energy that then becomes kinetic later. So that's your storage battery becomes solar power lifting all these weights up into the air. So it's a successful way to store the solar energy that you had earlier and then you

• 46:56Neil deGrasse Tyson?

  could draw from it at any time of day or night.

• 46:59Harrison Greenbaum?

  That's amazing.

• 47:00Neil deGrasse Tyson?

  It's very clever. Yeah.

• 47:01Harrison Greenbaum?

  There's a lot of balls at the top of hills and like, don't touch them. This is powering the whole city.

• 47:08Neil deGrasse Tyson?

  Yeah. So anyhow, there you have it. That's everything that was not even asked in that question answered about where energy comes from.

• 47:17Harrison Greenbaum?

  And I like dirty byproducts. I'm gonna make that my next comedy album. It's gonna be called Dirty Byproducts.

• 47:21Neil deGrasse Tyson?

  Dirty Byproducts.

• 47:22Harrison Greenbaum?

  All right, we have one more question.

• 47:23Neil deGrasse Tyson?

  We've got time for one more. Go give it to me.

• 47:25Harrison Greenbaum?

  Uh, it's, it's from Cicero Artifon. Hey, smart people.

• 47:30Neil deGrasse Tyson?

  You gotta admit, that's a cool name.

• 47:30Harrison Greenbaum?

  It's a really cool name. It's like a sci fi hero name.

• 47:32Neil deGrasse Tyson?

  I want that name, Cicero Artifon.

• 47:34Harrison Greenbaum?

  Yeah, he's the hero of like a Blade Runner kind of trilogy, Cicero Artifon. Or he's like the president in The Hunger Games.

• 47:40Neil deGrasse Tyson?

  You need an evil variant of this.

• 47:41Harrison Greenbaum?

  Yeah, exactly. He can go either way. So hopefully, hopefully this Cicero is leaning towards good.

• 47:46Neil deGrasse Tyson?

  Yeah.

• 47:46Harrison Greenbaum?

  But he said, hey, smart people, Cicero from Toronto, Canada. He's from Canada, so probably good people.

• 47:51Neil deGrasse Tyson?

  Mm hmm.

• 47:52Harrison Greenbaum?

  Uh, Neil mentioned once that the element osmium 76 is heavier than gold 79. How can that be possible? Don't the elements have an increase of mass the lower they are on the table?

• 48:02Neil deGrasse Tyson?

  Uh, he's slightly misremembering what I said.

• 48:04Harrison Greenbaum?

  Oh, no.

• 48:05Neil deGrasse Tyson?

  That's okay. So as you go up the periodic table, the elements become more and more massive.

• 48:11Harrison Greenbaum?

  Right.

• 48:11Neil deGrasse Tyson?

  More and more massive. No doubt about it. You're packing more protons into the nucleus. He mentioned how many protons were in osmium. I forgot. He said 76. I'll believe him. Gold was 79, was it? Okay.

• 48:23Harrison Greenbaum?

  That's what he said, yeah.

• 48:23Neil deGrasse Tyson?

  Okay, uranium is 92. These are bigger, heavier atoms all the way. That's not what distinguishes osmium. If you create a lump of these materials,

• 48:36Neil deGrasse Tyson?

  a lump of osmium, a lump of gold, a lump of them, how close together will the atoms pack in this lump that you have created? That's the question. It turns out, given the properties of atoms and the periodic table and the quantum physics of nuclei and energy levels in atoms, you can pack osmium atoms closer together than all the other kinds of atoms, thereby making the densest element, not the heaviest element, the densest element. Because now they're packed in close together. So osmium would make the world's best paperweight.

• 49:18Harrison Greenbaum?

  I mean, it could make a wedding ring. How come we don't use it in place of any of these precious metals?

• 49:23Neil deGrasse Tyson?

  Why would you, why'd you want it to be heavier? But we like gold.

• 49:27Harrison Greenbaum?

  This way you remember that you're married. I'd be like, oh my God, I can never forget. I can barely lift my hand.

• 49:33Neil deGrasse Tyson?

  That's a ball and chain analogy. Here's an osmium ball you're gonna carry around. So, so that's, that's the only difference. And just to quantify that, how dense these things are, a cubic foot of gold, oh my gosh. It's like, you know, it's, it, gold has two and a half times the density of iron. That's gold. And osmium tops that. And osmium, I think, may be used in the tips of some fountain pens. Because it has to be very hard, because you're pressing on it, there's a lot of pressure there. So it has its utilities.

• 50:12Harrison Greenbaum?

  Sure.

• 50:12Neil deGrasse Tyson?

  But paperweights are not among them.

• 50:16Neil deGrasse Tyson?

  So that's why we're talking about the density of an aggregate of those atoms, not the weight of an atom itself.

• 50:22Harrison Greenbaum?

  Nice. Well, thank you.

• 50:23Neil deGrasse Tyson?

  All right. I think that's all the time we have.

• 50:25Harrison Greenbaum?

  Amazing.

• 50:26Neil deGrasse Tyson?

  Well, it's great to have you back.

• 50:27Harrison Greenbaum?

  Thank you. It's been so great to be here.

• 50:28Neil deGrasse Tyson?

  It's very good.

• 50:29Harrison Greenbaum?

  I appreciate it.

• 50:29Neil deGrasse Tyson?

  Yeah, yeah. And you're, so how do we find you in the city?

• 50:33Harrison Greenbaum?

  They can find me on social media at HarrisonComedy on Instagram.

• 50:36Neil deGrasse Tyson?

  HarrisonComedy?

• 50:37Harrison Greenbaum?

  HarrisonComedy and HarrisonGreenbaum.com is my website.

• 50:41Neil deGrasse Tyson?

  Okay, excellent. And you perform?

• 50:43Harrison Greenbaum?

  I perform every night. I'm all over. I have my Off Broadway Comedy and Magic Show on Saturdays at Asylum NYC.

• 50:48Neil deGrasse Tyson?

  When you're on Broadway.

• 50:51Neil deGrasse Tyson?

  No, no, it's great.

• 50:52Harrison Greenbaum?

  Well, if enough people buy tickets, maybe.

• 50:54Neil deGrasse Tyson?

  So it's a gig? No, it's great because you do magic and comedy. And we love you here. We'll try to get you back.

• 51:00Harrison Greenbaum?

  I would love that. Thanks so much.

• 51:01Neil deGrasse Tyson?

  All right. This has been StarTalk, Cosmic Queries Grab Bag Edition with Harrison Greenbaum.

• 51:07Harrison Greenbaum?

  That's me.

• 51:07Neil deGrasse Tyson?

  All right. We'll see you next time. As always, keep looking up.