Moonmoons, Gravitons, and More!

What if the solar system had two suns? Neil deGrasse Tyson and Chuck Nice give a sneak peek into our patron-only Q&As with questions about the three body problem, galaxy formation, the alpha centauri system, and more.

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

• 0:02Neil deGrasse Tyson?

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

• 0:16Neil deGrasse Tyson?

  Hi, I'm Neil deGrasse Tyson, your personal astrophysicist and of course, host of StarTalk. For this episode, we're doing something we've never done before and might not ever do it again. First, you might not know that we have a Patreon page where you can support what we do. And when you become a Patreon member, basically become a patron of StarTalk, you give us the latitude to experiment in many different ways of bringing science down to earth. Well, in this new tiering system, the entry level is $5 a month. For $5, what you do is you get to ask exclusive questions about the universe.

• 1:01Neil deGrasse Tyson?

  And these are exclusive sessions only for Patreon members. It's cosmic queries just for you. And what we're gonna do this time is give you a taste of what that has been. At just at that entry level, there are other perks at other higher levels. You can check it out, okay? But for this episode, what we've done is getting the best of the Patreon cosmic queries. And we put them together and I'm there fielding those questions with my comedic co-host Chuck Nice. He reads me the questions. I've never seen the questions before he reads them. And we just have a fun time riffing. And anyone can listen to this episode.

• 1:44Neil deGrasse Tyson?

  Previously, it was only available behind the paywall, basically. And so now you'll get a taste of what will still live behind the paywall. And these are exclusive questions and answers for Patreon members. At that base level of $5 a month. So let us begin. Here I am with Chuck Nice with the greatest hits of Patreon cosmic queries. Check it out.

• 2:15Chuck Nice?

  All right, here we go. This is Bruno Faria, who says, hello, Dr. Neal and Chuck. I'm Bruno from Brazil. My question is, the space is in constant growth. Does that matter? Like planets and for us, like the space between our molecules? Or the space between atoms?

• 2:43Neil deGrasse Tyson?

  Ooh, he's getting, ooh, ooh, ooh, ooh. Bruno, thanks for that question. So first of all, right now, the expansion of space is not strong enough on the scales of solar systems and planets and moons for that stretching to manifest, okay? To reveal itself. So, but as this continues, what will happen is the stretching power of the expanding universe will begin to manifest on solar system scales and planets will get separated from their host stars and fly off into oblivion. Then eventually, so it will begin to overcome the gravity that's going on in tight quarters.

• 3:26Neil deGrasse Tyson?

  Then it'll begin to overcome the electromagnetic forces and it'll start separating atoms in the molecules that they were once made of. Then that'll continue and then start interfering with the strong nuclear force and then start separating atoms. And as that continues, in 10 to the 20, no, in 20 billion years, if the stretching goes unchecked, it will reach a point where it will want to stretch the very fabric of what comprises the spacetime continuum.

• 4:02Chuck Nice?

  Oh, shoot.

• 4:02Neil deGrasse Tyson?

  The pixels, the 3D pixels that construct the universe in which we live, it'll come a point where those pixels cannot even hold together and it wants to stretch those, but you can't stretch it anymore than you can stretch a fabric beyond a particular point. And that, what happens at that point, Chuck?

• 4:22Chuck Nice?

  The Big Rip, baby!

• 4:23Neil deGrasse Tyson?

  It's the Big Rip. It's the Big Rip. So Bruno, you just described the Big Rip. You just laid the seeds of the Big Rip as this stretching force, this, this, it's basically dark energy, which continues to overcome these other forces that are trying to make life possible. And yeah, if that goes unchecked, that's, that's the end, period. And I lose sleep over what that even looks like, what that would be like.

• 4:50Chuck Nice?

  Yeah. Well, by the way, that was a painterly and eloquent description, and I love the 3D pixels of the universe. That is brilliant.

• 5:02Neil deGrasse Tyson?

  I don't know what else to call them, but that's what they are. And it's called a Planck length. It's called, named after Max Planck.

• 5:07Chuck Nice?

  Well, that's, that's, yeah, I've, I've, now, Planck length I've heard, but 3D pixels of the universe? That's, that's beautiful. I love that.

• 5:16Neil deGrasse Tyson?

  All right.

• 5:17Chuck Nice?

  All right. Here we go. Let's go. Matthew Power. Oh, he's like a secret agent. Dear Neil and Chuck, what's up? Why does our solar system and many galaxies seem to be disk-like and not atom-like with orbiting objects going around in all manner of ways? Oh, wow, look at that.

• 5:45Neil deGrasse Tyson?

  A person been thinking about this situation.

• 5:47Chuck Nice?

  Yeah, because, yeah, because it's like, a atom has like a round nucleus, so there's...

• 5:51Neil deGrasse Tyson?

  Well, our traditional representation of an atom is got, you know, the orbits in every angle. So let me use that as his iconographic reference.

• 5:59Chuck Nice?

  Yes.

• 6:00Neil deGrasse Tyson?

  To the atom. So, a couple, at first, it's a brilliant question. It perplexed people for centuries. And the first indication that maybe we were on to something was in the mid 1700s, like the literal, exact mid 1700s, 1750. Two people independently, Laplace, a mathematician, and the philosopher, what's the dude's name? It'll come to me in a minute. They both came up with what today we call the nebular hypothesis. Okay? Kant, Immanuel Kant.

• 6:32Chuck Nice?

  Oh, existentialist.

• 6:34Neil deGrasse Tyson?

  Yeah, exactly, exactly. So, so he did this on the side, and Laplace sort of figured this out because he knew some physics. But what they were imagining was that if you had a gas cloud... Because there's gas all over the galaxy. And if that's what you make stuff out of, right? How might that happen? So if a gas is kind of rarefied and thin, so you gotta sort of collapse it so that it can become solid stuff, okay? So as the gas cloud begins to collapse, what they knew was that however slowly it's rotating as a large gas cloud, as it gets smaller, it will rotate faster. That's it.

• 7:17Neil deGrasse Tyson?

  Just like the ice skater who brings in the arms. Right. They begin to rotate faster, okay? Well, as you rotate faster, there's this centrifugal force that prevents things from continuing to collapse in that disk direction. Because that's where the centrifugal forces are preventing it. But if you come in from the top and bottom, there's no centrifugal force preventing you. So you collapse like a pancake, keeping the flat shape. And this would be a very natural thing to happen in the universe. And sure enough, that's how you get flat galaxies. And our galaxy is flat. Other spiral galaxies are flat, and they're really flat.

• 8:01Neil deGrasse Tyson?

  And you say, how flat are they? How flat are they? Thank you for asking that. So are they as flat as a pancake? No, they're flatter. Flat as a crepe? They're like a crepe, or tortilla, yes. You want to be French or you want to be Mexican? Yeah, so our Milky Way is about 100 times as wide across as it is thick. And that's way thinner than a pancake. Yeah, that's paper. That's practically paper, right? So you get these shapes when that happens. So it happens to the galaxy. It happens to the solar system within the galaxy, right? So this is a very natural phenomenon. Now, let's say you don't participate in that collapse.

• 8:46Neil deGrasse Tyson?

  You're so far away, you don't care what anybody close up is doing. Well, you still might form things, but you're not going to be in a disk. Oh, my gosh, let's look far out in our galaxy. There's what we call the Oort Cloud of Comets. It's not a literal cloud of diffuse matter. It's just comets filling a space that completely surrounds the sun. And so we call that a cloud rather than a belt. Because belts are flat, like the asteroid belt.

• 9:14Chuck Nice?

  Right.

• 9:14Neil deGrasse Tyson?

  Kuiper belt.

• 9:15Chuck Nice?

  Right.

• 9:16Neil deGrasse Tyson?

  These are belts that are flat and they go around the sun in the plane of the solar system. You go far enough out, so those comets come in from every which way around the solar system. So they do represent a spherical distribution of icy bodies. Comets, they come from the orange clouds. They're very long periods, like hundreds, tens and hundreds of thousands of years. Because it's very far out for them to make their complete loop. And so, so it's a great question.

• 9:44Chuck Nice?

  It is a great question.

• 9:45Neil deGrasse Tyson?

  We think we got that one solved. And by the way, all discs are made that way. So the, what are called accretion discs, the discs that form around black holes.

• 9:52Chuck Nice?

  Black holes.

• 9:53Neil deGrasse Tyson?

  Yeah, it's a general phenomenon in the galaxy.

• 9:55Chuck Nice?

  So let me ask you this.

• 9:56Neil deGrasse Tyson?

  Oh, by the way, and people in their middle age who gain weight around their belt.

• 10:00Chuck Nice?

  Uh huh.

• 10:00Neil deGrasse Tyson?

  In my field, we would joke and say, you have an accretion disk.

• 10:05Chuck Nice?

  Well, that sounds a lot better than a beer belly.

• 10:08Neil deGrasse Tyson?

  Beer belly, beer belly, pot belly, yeah.

• 10:09Chuck Nice?

  Right.

• 10:10Neil deGrasse Tyson?

  I have an accretion disk.

• 10:10Chuck Nice?

  I have an accretion disk, yes. No, you're fat.

• 10:13Neil deGrasse Tyson?

  Uh, right.

• 10:14Chuck Nice?

  So the spinning can happen in any direction first to create the flat because...

• 10:20Neil deGrasse Tyson?

  There's going to be one, that's a great question. There's going to be one orientation that dominates.

• 10:23Chuck Nice?

  That's what I'm saying, yes.

• 10:25Neil deGrasse Tyson?

  Because, because the cloud cannot spin in all directions at once.

• 10:28Chuck Nice?

  Right.

• 10:28Neil deGrasse Tyson?

  Because it would, it would collide with itself, like two marshmallows, hot marshmallows hitting. They collide and attach. And so that stuff settles out and it finds the dominant axis around which to rotate.

• 10:39Chuck Nice?

  So is that why you can look out and see galaxies in different positions?

• 10:46Neil deGrasse Tyson?

  Yeah, so that, so the spiral galaxies can be face on, edge on.

• 10:49Chuck Nice?

  Right.

• 10:50Neil deGrasse Tyson?

  And you get to see all of, no, no, they'll, they'll form wherever their gas cloud, their native gas cloud, whatever that orientation was. But now, here's something. Suppose you formed stuff. Suppose you formed your stars before the gas collapsed to the middle.

• 11:07Neil deGrasse Tyson?

  Wait a minute then, you're not gonna get a disk.

• 11:09Chuck Nice?

  Right.

• 11:11Neil deGrasse Tyson?

  Because they'll orbit around the center, but they're not gonna collapse and stick to itself. So we, such a galaxy does exist, they're called elliptical galaxies. These are fully sort of puffed up, three dimensional spherical elliptical shapes. And they have very low gas. There was no gas making that disk happen. So we know-

• 11:30Chuck Nice?

  They must be lovely at a party.

• 11:33Neil deGrasse Tyson?

  Gas free. So, so we know that the planets of the solar system all formed after the gas of the solar system had collapsed.

• 11:42Chuck Nice?

  Wow.

• 11:43Neil deGrasse Tyson?

  The Kuiper, the, the, the Oort cloud of comets, those formed after. Okay, and they did not form out of, uh, they did not require the collapsing gas cloud to form. And so they're still in their, in their atomic orbits around the sun. So it's a great question.

• 12:01Chuck Nice?

  Here we go. Andrea or Andrea Sparini says this, hello Neil and Chuck, if I were an astronaut floating in intergalactic space, and I could remove all matter from the visible universe, where would I be? And what would my eyes be able to see if the boundaries of the universe would wrap around my body? Thanks for coming to me on my long walks with your podcast, my long walks to the edge of the universe.

• 12:32Neil deGrasse Tyson?

  Yeah, don't walk too far.

• 12:33Chuck Nice?

  Yeah, don't walk too far, girl. All up. Talking about where would you be with no matter at all?

• 12:39Neil deGrasse Tyson?

  So generally where you are only has meaning in reference to something else. Right? So there's an interesting philosophical dilemma, right? So if I, we are a certain number of degrees west of the Greenwich prime meridian, and we're a certain number of degrees north of the equator, all right? So we're basically like 74 degrees west, 41 degrees north. That, so that's where we are on Earth's surface relative to a coordinates that have been pre-established. Okay, but then where are those coordinates?

• 13:23Neil deGrasse Tyson?

  All right, so the prime meridian is like zero. And so where are those in relationship to anything else? We can say that they're 74 degrees east of us, but that would make us the preeminent prime, you know, estabisher of the coordinate system, but we know we're not. So at some point, you have to arbitrarily declare the coordinate system and then reference everything else to it. And everyone then has to agree that you've done that. Otherwise, people don't know where they are relative to each other. All right? You know where you are relative to some grid that you set up in your backyard, and somebody else set up some other grid, and you will never communicate accurately with each other or productively.

• 14:07Neil deGrasse Tyson?

  So everybody's got to agree. So the prime meridian was established by international agreement. Okay? To go, by the way, it almost went through Paris, the Paris Observatory. France was bucking for the prime meridian back when it was up for grabs, and England won out. It's rumored that France conceded the prime meridian in exchange for everybody adopting the metric system. So, because they came up with the metric system.

• 14:39Chuck Nice?

  Not a bad, not a bad trade.

• 14:41Neil deGrasse Tyson?

  Yeah, the quid pro quo of historical science and metrics. But anyhow, so if you are, if you are between galaxies, and galaxies are the things that dot the observable universe, and then you start removing the galaxies, yet you have no coordinate system. But what you will know, because we kind of know this, is that you are still nonetheless in the center of your own horizon. But you can't see the edge of your horizon because there's nothing to allow you to measure it. So, and by the way, we think of horizons as two dimensions, like out at sea, but in space, your horizon is all around you in every direction. So it's a spherical horizon. And by the way, it's confusing.

• 15:24Chuck Nice?

  That's gotta be disorienting. Now, you want to talk about your wife getting mad because you don't ask for directions.

• 15:28Neil deGrasse Tyson?

  Now you can get lost in all three dimensions.

• 15:31Chuck Nice?

  Right, now you're lost in all three dimensions at once.

• 15:34Neil deGrasse Tyson?

  Am I up, down, left, right, north, south, before, backward? So, so yeah.

• 15:42Chuck Nice?

  Well, that's not making an Alpha Saturni.

• 15:46Neil deGrasse Tyson?

  So yeah, so there's no, if there's no coordinate system established, it doesn't make sense to say where you are, other than to say you're at the center of your own horizon, which isn't very helpful. But then again, do you really need to know where you are if there's no place to go?

• 16:02Chuck Nice?

  Oh, snap. Look at that. That has been my, that has been my life for an entire year now.

• 16:10Neil deGrasse Tyson?

  No place to go.

• 16:12Chuck Nice?

  I've spent my whole life for a year now.

• 16:14Neil deGrasse Tyson?

  I don't care where my current coordinates are because I have no coordinates I need to visit.

• 16:19Chuck Nice?

  That's it.

• 16:20Neil deGrasse Tyson?

  That's a profound.

• 16:21Chuck Nice?

  I'm not going anywhere. That's the problem.

• 16:24Neil deGrasse Tyson?

  But even if you were, you're not hit, even if you picked a direction, you're not headed anywhere.

• 16:29Chuck Nice?

  That's right. Right. Yeah.

• 16:31Neil deGrasse Tyson?

  Because there's no place waiting for you. It's all been removed from the universe by Andrea.

• 16:37Chuck Nice?

  Yeah, Andrea, I gotta tell you, this got really sad very quickly.

• 16:41Neil deGrasse Tyson?

  Got sad fast.

• 16:42Chuck Nice?

  This got sad fast.

• 16:46Neil deGrasse Tyson?

  By the way, but it is true, if you're navigating within the galaxy, you're not going to be using GPS on Earth. So we're thinking in the future, as we move throughout the Milky Way, we would set up a grid system targeting pulsars that are scattered because they're very fast rotating and they send radio pulses in for having rotated in their configuration. And that gives you a place to look and you can get a timing system based on that and a system of locations within the galaxy, much like GPS on Earth. So pulsar GPS is going to be the future of space travel.

• 17:21Chuck Nice?

  Wow.

• 17:24Neil deGrasse Tyson?

  We're going to take a quick break, but when we return, we will continue to dig in deep to our Patreon exclusive question and answer archive. With Chuck Nice. We'll be back in a moment.

• 17:48Speaker 02

  Hi, I'm Chris Cohen from Hallworth, New Jersey, and I support StarTalk on Patreon. Please enjoy this episode of StarTalk Radio with your and my favorite personal astrophysicist, Neil deGrasse Tyson.

• 18:10Neil deGrasse Tyson?

  Welcome back to StarTalk. This episode is a collection of cosmic queries asked by our Patreon patrons. We reached back into the archives of our monthly Patreon-only episodes to find some of our favorite moments of questions and answers to share with you. So let's find out what Chuck asks me next, fed to us by our Patreon members.

• 18:39Chuck Nice?

  Well, let's start at the top here. This is Denny. Denny is saying greetings from Germany.

• 18:47Chuck Nice?

  It says, "I wonder why so many people believe the aliens will fly in a disk-shaped ship? Is there any physical advantage in building aircrafts in that shape?"

• 19:00Neil deGrasse Tyson?

  No. Next question.

• 19:04Neil deGrasse Tyson?

  It's like, no. No. Yeah, we've got this trope in our head, right? And once the seed gets planted, it's kind of hard to shake it. And so I remember, do you remember the show Lost in Space?

• 19:21Chuck Nice?

  Of course.

• 19:21Neil deGrasse Tyson?

  Okay, I think we talked about this once, where, you know, these spacecraft only sort of levitate when they rotate, right?

• 19:29Chuck Nice?

  Right.

• 19:30Neil deGrasse Tyson?

  Like, they're rotating discs.

• 19:31Chuck Nice?

  Right.

• 19:32Neil deGrasse Tyson?

  But there they are, on the ship, looking out a window at the same destination even though the whole thing is rotating. That very much disturbed me.

• 19:47Chuck Nice?

  So.

• 19:48Neil deGrasse Tyson?

  Why isn't everything just whizzing by left and right? And so, yeah, it just doesn't, there's, I mean, yes, a disk has nice aerodynamics. Okay, but most of a journey through space has no air. So it doesn't have to be aerodynamic at all, really. So there's a lot of, there's a lot of problems with that shape.

• 20:10Chuck Nice?

  It's why my favorite, my favorite spaceship in all of sci fi is the Borg ship from Star Trek, which is a giant cube. The least aerodynamic thing ever.

• 20:25Neil deGrasse Tyson?

  There it is. There, they said, you know, we got this. We don't need, we don't need to be sleek. We don't need to be, but in that same vein, the Enterprise didn't have to be that aerodynamic looking, right? Because it was never in the atmosphere. It was always out, out in the, out in the empty space. Yeah, so that's a great question. And I've, in my whole life, I have not found any legitimate aerodynamic reason or any other reason to design a ship that way. By the way, there's a little bit of physics that people don't, you know, if you're just making up stories, you typically miss it.

• 21:03Neil deGrasse Tyson?

  If you are in open space and you set something rotating in one direction, something has to go rotating in the exact opposite way to counterbalance that. So in other words, if it starts not rotating and then begins to rotate, something inside of it has to rotate the opposite way to cancel out what's called the angular momentum. If you have a flying saucer that's just there floating, it has zero rotational angular momentum. Okay, I was just redundant there. Zero angular momentum. Okay, zero.

• 21:43Neil deGrasse Tyson?

  So if any part of it starts rotating in one direction, some part of it has to rotate the opposite way to cancel out the angular momentum.

• 21:56Neil deGrasse Tyson?

  Because you can't just set yourself into rotational motion. Unless you have rocket, little rocket vectors.

• 22:02Chuck Nice?

  Right, right.

• 22:03Neil deGrasse Tyson?

  Yeah, and then you're spewing out gases in one direction, and that maintains the momentum. So to see these, all these sci-fi things, they just rotate. No, it's violating deep laws of physics. Laws of physics that no alien is going to circumvent.

• 22:19Chuck Nice?

  And the funny thing is, you see them rotating, and like you say, there's, if there's zero reason for it.

• 22:29Chuck Nice?

  There's absolutely no reason for it.

• 22:31Neil deGrasse Tyson?

  Imagine a 747, say, okay, we'll start rotating now.

• 22:35Chuck Nice?

  Right.

• 22:35Neil deGrasse Tyson?

  For what?

• 22:36Chuck Nice?

  For what? It's like, you don't fly and barrel roll your way over to Europe.

• 22:41Neil deGrasse Tyson?

  Exactly.

• 22:42Chuck Nice?

  You know, there's no reason to barrel roll the plane the entire way you're going to Europe. It's stupid.

• 22:48Neil deGrasse Tyson?

  Exactly, exactly.

• 22:49Chuck Nice?

  Wow.

• 22:50Neil deGrasse Tyson?

  Anyhow.

• 22:51Chuck Nice?

  All right, that was cool, man.

• 22:53Neil deGrasse Tyson?

  Yeah, great question.

• 22:57Chuck Nice?

  Watch this. This is Elaine in the Stars, says, hey, Dr. Tyson, Lord Nice, can a moon have a moon?

• 23:08Chuck Nice?

  Ooh, I like, I just love the whole, you know, positioning of that. Can a moon have a moon?

• 23:16Neil deGrasse Tyson?

  Yes.

• 23:18Chuck Nice?

  You sound very skeptical when you say that.

• 23:22Neil deGrasse Tyson?

  Yes?

• 23:24Chuck Nice?

  Your yes is very suspect, Neil.

• 23:27Neil deGrasse Tyson?

  You got, it's gotta be very zonal, okay? So the first moon has to be far enough away from the main planet so that the moon around the moon, when it orbits around, is not badly affected when it's on the near side compared to the far side.

• 23:44Chuck Nice?

  Right.

• 23:45Neil deGrasse Tyson?

  Okay? You gotta make sure your orbits can stabilize out. Because orbital allegiance can get very complicated. If you have three objects, okay? It's called the three-body problem. And it's very, it's basically chaotic, the three-body problem, except in very restricted cases. So, in other words, the sun, earth, and moon is a three-body problem. But we're so far the hell away from the sun that our moon can hang out here without thinking, oh my gosh, now I have to go hang out and orbit the sun, right? It doesn't have orbital allegiance problems. If Earth were orbiting much closer to the sun.

• 24:24Chuck Nice?

  Right.

• 24:25Neil deGrasse Tyson?

  Then the moon, as it comes around the backside or the front side, will say, hey, the sun is tugging me more than you are, Earth.

• 24:32Chuck Nice?

  That's right.

• 24:33Neil deGrasse Tyson?

  I'm gonna go that way. And then it destabilizes everything. So the consequences of destabilized orbits is you'll fall into the sun, or you'll fall into the main planet, or you'll get ejected forever. We think the solar system started with at least 30 planets when it originally formed. And it was just a jockeying for stable orbits. And not everybody wins that contest.

• 24:57Chuck Nice?

  Hmm, so there you go.

• 24:58Neil deGrasse Tyson?

  Most lose. Yeah.

• 25:00Chuck Nice?

  There you go. What you won't do for your moon, some other planet's gravity will.

• 25:04Neil deGrasse Tyson?

  It's gonna take it, take it off.

• 25:06Chuck Nice?

  Just better remember that.

• 25:09Chuck Nice?

  Girl, you gonna let him treat you like that, girl? You gonna let him treat you like that?

• 25:15Neil deGrasse Tyson?

  Wait, come back. No, I'm switching. I'm switching my allegiance.

• 25:23Neil deGrasse Tyson?

  So, yeah, so moons can have moons. And in the same way, if you think of Earth as a moon to the sun, we have a moon. You can think about it that way.

• 25:31Chuck Nice?

  So it's really a three-body problem. There you go.

• 25:33Neil deGrasse Tyson?

  Yeah, and orbits tend to be highly unstable. So, and by the way, you can invert that and say, uh, you can have double star systems, such as what was portrayed in the first of the Star Wars movies, which is of course Star Wars, Episode IV, okay?

• 25:53Neil deGrasse Tyson?

  And he walks out, he's on the sand planet or whatever, and he sees a double sunset. All right? That's, that's the only accurate science in the entire Star Wars series.

• 26:07Neil deGrasse Tyson?

  Soundtrack by Chuck Nice.

• 26:10Chuck Nice?

  I feel, I felt like you needed a little, a little Star Wars music bed for that. Every, that's an iconic scene, by the way.

• 26:19Neil deGrasse Tyson?

  You know, a long time ago, in a galaxy far, far away. So in other words, those two stars are orbiting close to each other.

• 26:29Chuck Nice?

  Right.

• 26:29Neil deGrasse Tyson?

  And the planet is orbiting much farther away.

• 26:33Chuck Nice?

  Right.

• 26:33Neil deGrasse Tyson?

  So that's the inversion of this problem. You can have two main bodies.

• 26:36Chuck Nice?

  Right.

• 26:37Neil deGrasse Tyson?

  But they have to be far away and close to each other. So that as you orbit them, you don't know that one is closer to you than the other because they're sort of, it's a smoothed out sort of gravity field. But the moment those two stars are far apart, or you orbit close to them, forget it. You're in an unstable situation. There you go.

• 26:55Chuck Nice?

  Awesome.

• 26:59Chuck Nice?

  There we go. Let's go to TJ Monroe. TJ says this, Dr. Tyson, now this is TJ speaking here.

• 27:07Neil deGrasse Tyson?

  Okay.

• 27:08Chuck Nice?

  I ain't got nothing to do with this.

• 27:09Neil deGrasse Tyson?

  You're pre-disassociating yourself.

• 27:12Chuck Nice?

  I am pre-disassociating, okay?

• 27:14Neil deGrasse Tyson?

  All right.

• 27:15Chuck Nice?

  Dr. Tyson, the is a graviton.

• 27:22Chuck Nice?

  There you go. Thanks TJ.

• 27:25Neil deGrasse Tyson?

  Okay. Graviton is a proposed quantum particle of gravity. They've yet to be detected. So it's, is, is it, a graviton is to gravity, gravitational waves, what a photon is to light waves?

• 27:43Chuck Nice?

  Wow.

• 27:44Neil deGrasse Tyson?

  All right. So we, we think of light as waves and it moves through space.

• 27:47Chuck Nice?

  Right.

• 27:48Neil deGrasse Tyson?

  And that's fine. Okay. And you can measure them as waves depending on your apparatus. We can also measure it as photons.

• 27:54Chuck Nice?

  Right.

• 27:55Neil deGrasse Tyson?

  Provided you have the right apparatus. And when you do, you have concluded and demonstrated that light behaves both as a particle, as a wave and as a particle, both of them. Okay? We have already measured gravitational waves. From colliding black holes, the LIGO Observatory, Laser Interferometer Gravitational Observatory, that measured waves. So do we have an apparatus yet that can measure the quantum particle that gravity represents? And we don't. But we're not given reason to think it wouldn't exist. So it's out there, it's dangling above our heads. Maybe it doesn't exist. And if it doesn't, that would be interesting, too. So the graviton is the force propagator of gravity,

• 28:39Neil deGrasse Tyson?

  in the way that the photon is the force propagator of electromagnetic energy, in the way that the gluon is the force propagator of the strong force. And in the way the intermediate vector boson is the force propagator of the weak force. So all four forces have an on. Photon, boson...

• 29:03Chuck Nice?

  Gluon.

• 29:04Neil deGrasse Tyson?

  Gluon and a graviton. There it is.

• 29:08Chuck Nice?

  There you go.

• 29:09Neil deGrasse Tyson?

  Simple.

• 29:10Chuck Nice?

  There you go, there you have it. So add that to your stick-on.

• 29:17Chuck Nice?

  Hopefully that clears some things up for you.

• 29:23Chuck Nice?

  Here we go. This is Kevin the Semmelier, who is also a friend. If you weren't the director of the Hayden...

• 29:30Neil deGrasse Tyson?

  Kevin, recommend a wine next time. We told you this.

• 29:33Chuck Nice?

  That's right, Kevin. You didn't do it.

• 29:35Neil deGrasse Tyson?

  And call yourself a Semmelier. If you don't recommend a wine, you know, I don't know. We have to part ways, okay?

• 29:40Chuck Nice?

  Okay, there you go, Kevin. The gauntlet has been thrown down. You must recommend a wine next time.

• 29:45Neil deGrasse Tyson?

  All right, next time.

• 29:46Chuck Nice?

  Kevin says this. If you weren't the director of the Hayden Planetarium, what do you think you would be doing?

• 29:52Neil deGrasse Tyson?

  Oh.

• 29:52Chuck Nice?

  Oh. And this is a question to a man who knew, when he was like nine years old, that he was going to be an astrophysicist. So that's a damn good question.

• 30:02Neil deGrasse Tyson?

  Okay, so I have a cop-out answer. And that is, if I didn't spend so much time thinking about how other people learn, and how they think, and what brings joy to them about the universe, I would just be an astrophysicist unheard of in a lab somewhere. And you would never know my name, because no one would come to me for soundbites.

• 30:18Chuck Nice?

  No, you don't get to do that.

• 30:20Neil deGrasse Tyson?

  No, yeah, that's...

• 30:21Chuck Nice?

  No!

• 30:22Neil deGrasse Tyson?

  Let me...

• 30:23Chuck Nice?

  No!

• 30:23Neil deGrasse Tyson?

  Okay, fine.

• 30:24Chuck Nice?

  You can't be an astrophysicist still.

• 30:27Neil deGrasse Tyson?

  Okay, you gotta pick something else. Okay, he said director of the planetarium. This is true. What else would I be? And I said I'd be a, I'd be hidden in a lab somewhere. But you'd still be an astrophysicist, which means you're... Yes, I would. That's not what he asked. Yeah, I know he didn't ask that, but... Fine, fine, fine. Go ahead. Okay, you know what I'd do? What? But this has to be another universe. It wouldn't happen in this universe. Okay. I'd be, I'd be a songwriter for Broadway musicals. Ooh, now there we go. Okay. Because I love putting word to page and putting a rhyme that's simple. And two people fall in love. And they're so, they're so overrun by that emotion that they have to stop and sing a song about it. Oh, my God, I can see it now. "The Night Sky" by Neil deGrasse Tyson.

• 31:12Neil deGrasse Tyson?

  "Don't you love the night sky?"

• 31:16Neil deGrasse Tyson?

  The reason why I'd have to be in another universe is because I don't know how to sing and I don't know how to write music. Okay. So that's a whole other universe, a parallel verse. That's cool. That I'd have to do that in. But thanks for that question, Mr. Solman.

• 31:32Neil deGrasse Tyson?

  We're gonna take another quick break, but when we return, more Patreon-only Cosmic Queries that have never before been posted beyond the exclusive Patreon page.

• 31:59Neil deGrasse Tyson?

  Welcome back to the special edition of Cosmic Queries. And before we bring you to the third and final segment, let me just remind you that these Cosmic Queries were mined from years of Patreon-exclusive content. And we are bringing that across the divide so you can get a taste of what an entry-level Patreon membership will bring you at $5 a month. So, picking up on the greatest hits of Cosmic Queries, here's Chuck and me doing our best to answer some of the coolest, craziest, wacky questions on the internet.

• 32:41Chuck Nice?

  Eric Vargas says this. "Hey Chuck, hey Neil, just observing the stars in our galaxy, we know that most solar systems are binary. Could it have been possible in the early formation of our solar system that we used to have two suns? And that our sun kicked out another star from our system? Like an evil twin? Or a wife kicking out a husband after an argument?"

• 33:02Neil deGrasse Tyson?

  That is not in the... That is not in the main question. That is not...

• 33:06Chuck Nice?

  How did you know that?

• 33:10Chuck Nice?

  How the hell did you know that? Did I put that in there? That's amazing.

• 33:13Neil deGrasse Tyson?

  So Chuck, go back out to the front lawn and bring your clothes back in. And your stereo system.

• 33:20Neil deGrasse Tyson?

  I don't need to know all your business.

• 33:22Chuck Nice?

  And also, could life have evolved on Earth if we did have two suns? Okay, so there you go.

• 33:27Neil deGrasse Tyson?

  So let me sharpen what they said. Most stars in the night sky, when you take a telescope to them, will reveal more than one star in mutual orbit.

• 33:36Chuck Nice?

  Right.

• 33:37Neil deGrasse Tyson?

  So more than half the stars are double multiple star systems.

• 33:40Chuck Nice?

  Sweet!

• 33:41Neil deGrasse Tyson?

  Turns out planetary orbits are not particularly stable under those conditions. And because their gravitational allegiance gets challenged every time. Are you too close to one or too far from the other?

• 33:53Chuck Nice?

  Come on over here! No, come on over here!

• 33:55Neil deGrasse Tyson?

  Exactly.

• 33:55Chuck Nice?

  Come on over here! No, come on over here!

• 33:57Neil deGrasse Tyson?

  Exactly. And so you can get chaotic orbits and even unstable orbits and they'll fly away. So we expect the most stable systems of planets to be happily orbiting single stars. But it is possible to have two stars orbiting so close together. And you, the planet, orbiting far enough away that there's a smeared common gravity between the two and you don't feel this competing allegiance. Okay, so you can construct a star system where that's the case. And that's what was in Star Wars, Episode IV. The Great Hope or the Hope Diamond? What's the name of that? The New Hope.

• 34:38Chuck Nice?

  The New Hope.

• 34:39Neil deGrasse Tyson?

  The New Hope. A New Hope. Episode IV, where Luke is out, he's in the sand planet, wherever, and there's a double sunset there.

• 34:46Chuck Nice?

  Yes.

• 34:47Neil deGrasse Tyson?

  I want you to notice that those stars are not far apart from each other. They're near each other on the sky. So that planet he was on can sustain a stable orbit around it. And you can evolve life and have everything that you would want and need. And that is the only correct science in all... Star Wars movies combined.

• 35:06Chuck Nice?

  Damn, damn, oh.

• 35:08Neil deGrasse Tyson?

  Just saying.

• 35:09Chuck Nice?

  Oh, that hurt.

• 35:10Neil deGrasse Tyson?

  Not even the bar scene, come on.

• 35:16Neil deGrasse Tyson?

  Okay, the bar scene, but other than that.

• 35:18Chuck Nice?

  Okay, okay, okay, okay.

• 35:21Neil deGrasse Tyson?

  So, there's nothing wrong with having two stars as long as you're not gravitationally disturbed by it. Um, not a problem at all.

• 35:27Chuck Nice?

  Sweet.

• 35:28Neil deGrasse Tyson?

  And, yeah, it'd be fun, you have double sunsets, and you have two shadows. But often the other sun is filling in the shadow that would be made by one of the suns. So you're not gonna have two distinct shadows, um, uh, coming out from you, the way you do on Broadway, when you have two collimated beams of light. You can get two distinct shadows there, um, because the light is only going in one direction, and you have a dark place and a light place around it. And in, uh, if it's two suns, it's showing light everywhere. So you're not gonna get beautiful double shadows, but you get double sunsets, those will be, those are twice as romantic.

• 36:01Chuck Nice?

  Sweet.

• 36:05Neil deGrasse Tyson?

  Okay, bring it on.

• 36:05Chuck Nice?

  Okay, this is Gabriella Dijkhofz. I, I think they're making this crap up now. D I J K H O F F Z. Hey Gabriella, here's the deal, um.

• 36:17Neil deGrasse Tyson?

  No, no, call her Gabby, call her Gab, just shorten the whole damn thing.

• 36:20Chuck Nice?

  Oh, by the way, I can't believe you said that, cuz I just looked as she ends it. Thanks, Gabby.

• 36:27Chuck Nice?

  Alright, she goes, hey Neil, Chuck, Happy New Year. What do we know about any plans for an Alpha Centauri-related expedition? Manned or unmanned? Thanks.

• 36:36Neil deGrasse Tyson?

  So, just to remind people, Alpha Centauri is the closest star system to the sun. Four light years away, alright? Four, so that's, that's in our backyard, cosmically speaking.

• 36:48Chuck Nice?

  So your answer is none?

• 36:50Neil deGrasse Tyson?

  No way, wait, so four light years, at the fastest we have ever sent a spaceship? Would take anywhere between fifteen and thirty thousand years to get there.

• 37:01Chuck Nice?

  Okay.

• 37:02Neil deGrasse Tyson?

  To get to the closest star system. And Alpha Centauri is visible primarily from the southern hemisphere. You can catch it if you go as far south as like Florida. If I remember its location, but everybody in the southern hemisphere can see it. It's a relatively bright star. It's bright because it's nearby more than because it's intrinsically bright. And notice I call it a star system. It was named Alpha Centauri because it's the brightest star in the constellation Centaurus. Okay? And so for many, not all, many constellations, we see the stars and you just, in the old days. Today, we would do it differently, but Alpha, Beta, Gamma, Delta, Epsilon, this sort of thing.

• 37:44Neil deGrasse Tyson?

  That's why Star Trek has, you know, Alpha Ceti V or something or whatever. There would be, Alpha Ceti would be the brightest star in the constellation Cetus. And V would be the fifth planet in that star system. So these are coding. So Star Trek was like first out of the box to try to create a lexicon for planets and planet types. But anyhow, so Alpha Centauri, we know is a star system. Okay? And so there's, it's a multiple star system. And the nearest star in that star system is called Proxima Centauri.

• 38:17Chuck Nice?

  Mm hmm.

• 38:18Neil deGrasse Tyson?

  I wonder why? Okay. Is it proximal to us? Is it, right, right, okay? So that star was recently discovered to have an exoplanet. And that's Proxima B. Okay? A would be the main star. We letter them by all the objects in the system. And A is the star, B is the planet. So Proxima B is an exoplanet. It's Earth-sized, sort of, you know? So, so it, we, fortuitously, the nearest star system, the nearest star of the nearest star system has a planet that's Earth-like. So yeah, that'd be the first one we'd visit if we were to go anywhere.

• 39:02Neil deGrasse Tyson?

  And can you, we have to kind of live forever for that to happen? And you have to convince someone, would you like to spend 70,000 years or 30,000 years of living forever on a ship headed towards a planet we don't know anything about? All right? And, and why would, what, and you, or have, make it a generational ship? And you have babies and then 12 generations, uh, what, uh, a thousand generations later, they'll get there and they'll wonder why the hell they got sent in the first place?

• 39:31Chuck Nice?

  Or just, or just invent light travel, light speed travel.

• 39:35Neil deGrasse Tyson?

  Oh, light speed travel.

• 39:35Chuck Nice?

  And it'll take four, four years.

• 39:36Neil deGrasse Tyson?

  And it'll take four years, correct. Or, or invent warp speed travel and then you get there faster than light. Or.

• 39:44Chuck Nice?

  15 minutes.

• 39:44Neil deGrasse Tyson?

  Or, or invent wormholes and you just step through a portal and you come out on the other side seconds later. So, so yeah, so there's no plans because we don't know how to do anything faster than chemical rockets at the moment. There is this, something called Project Starshot, which are these micro satellites. They're the size of a postage stamp and you can cram all kinds of electronics on something that's small these days, like, like, um, radio transmissions and, and gyroscopic stabilizers and, and power sources, because you can have a little solar panel thing that, all right? So there's a plan to have a boatload of these, launch them into space, have them open up

• 40:28Neil deGrasse Tyson?

  a solar sail, a light sail. All right? Now this is a little, it's like a sail and then have a set of lasers from Earth beamed to these sails and accelerate them towards Alpha Centauri. If you do the calculation right and the sails are large enough and the power of the lasers big enough, the lasers will impart an impulse into these craft. It will accelerate them to 20% the speed of light. Of course, the farther away they get, the weaker is the light signal. So this is all factored in. They'll get there 20% the speed of light, which means they'll get there in 20 years. Right? If you're 1/5 the speed of light and you're four light years away, do the math. It's 20 years. All right.

• 41:11Neil deGrasse Tyson?

  So and then they would beam signals back to us at the speed of light. That takes four years, so we could actually have an entire mission that unfolds over a 24-year period. And but the problem is, you know, you can do that because they're very light. You know, light as in they don't have much mass, whereas, you know, why can't we do that to people? Because you

• 41:34Neil deGrasse Tyson?

  people weigh too much.

• 41:35Chuck Nice?

  We just no, we just sent a bunch of jockeys.

• 41:38Neil deGrasse Tyson?

  Jockeys.

• 41:39Chuck Nice?

  Yeah, we just sent jockeys.

• 41:41Neil deGrasse Tyson?

  Yeah, I think that'd be even lighter, Chuck, than jockeys. Yeah, yeah. I imagine jockeys are strapped to solar sails and then

• 41:52Neil deGrasse Tyson?

  I think the jockey union would object, I think, but all right. You know, also our tiny people out there are coxswain for rowing. The cocks I used to row.

• 42:02Chuck Nice?

  Because they don't take up weight in the boat.

• 42:03Neil deGrasse Tyson?

  Yeah, I was a heavyweight boat, so it was called a heavyweight boat because I was 40 pounds lighter to row in it than than I am in this moment. But we were all the biggest guys, you know. I was 6'2", 196 pounds, and I was one of the littlest guys on the boat. I rode stroke, which is the person who sits right in front of the coxswain, who can't see any other rowers. So if I can't see any other rowers, you have to do what I do.

• 42:32Chuck Nice?

  That's all they can look at.

• 42:33Neil deGrasse Tyson?

  That's all they can look at. Right. So and the coxswain is, you know, someone who's usually barely five feet tall.

• 42:42Chuck Nice?

  6'2", 6'195, and you're the smallest guy on the boat. What was this, like a Viking row ship? Was there a guy, was the coxswain a guy with a drum just like boom?

• 42:55Neil deGrasse Tyson?

  We had it. We had a Norwegian guy in the middle of the boat. The middle four seats is called the engine room, four out of the eight seats. And he was 6'5".

• 43:08Neil deGrasse Tyson?

  Uh, probably two twenty-five, two thirty.

• 43:11Chuck Nice?

  It's crazy.

• 43:12Neil deGrasse Tyson?

  I can, I'll find a picture and I'll show you me standing next to it. Uh, and another, and we'll find another excuse to, to show that. Maybe when we do the physics of rowing, I'll pull out one of my rowing pictures.

• 43:22Chuck Nice?

  Cool.

• 43:22Neil deGrasse Tyson?

  On the medal stand, got a gold medal in that race. Um, anyhow, that was just one question.

• 43:27Chuck Nice?

  I know.

• 43:28Neil deGrasse Tyson?

  Why did I go on the wrong like that?

• 43:29Chuck Nice?

  Well, here's, here's one, here's one that's a little more personal that you'll

• 43:32Neil deGrasse Tyson?

  Mm-hmm.

• 43:33Chuck Nice?

  help someone with. And this is the artist formerly known as James Smith. Um, hey Neil, and I guess Chuck.

• 43:42Neil deGrasse Tyson?

  Uh. Well, he doesn't always know that you're gonna be the guy.

• 43:46Chuck Nice?

  That's true.

• 43:47Neil deGrasse Tyson?

  Okay.

• 43:47Chuck Nice?

  And so he goes, I'm thirty-seven from Indianapolis and I have been wanting to return to school. I really love math and science. Is it too late for me to get into astrophysics or astronomy? Or have the sands of time just run out on my cosmic scholarly journey?

• 44:01Neil deGrasse Tyson?

  Oh.

• 44:02Chuck Nice?

  Thank you so much for all you guys do. Love, James.

• 44:04Neil deGrasse Tyson?

  Okay. What do you think? We're gonna have to end with this question. It's a great question. So here you go. What I have come to learn, James, is that as human life expectancy increases, the cutoff times also go up with it. If there's a cutoff time, time for anything. So there was a day when, you know, you, you know, why was the retirement age put at sixty-five? Cause that's when most people died. Go look at the

• 44:32Chuck Nice?

  Actuarial genius!

• 44:34Neil deGrasse Tyson?

  Okay. Let's, let's go, go look at the actuarial tables from the nineteen thirties. Whenever they put in a sixty-five year retirement age, we were dying between sixty-five and seventy.

• 44:45Chuck Nice?

  It's great.

• 44:46Neil deGrasse Tyson?

  There's no one to collect on these shows. Right. So, so that, that's how that played out. All right? And now people are not even retired, they're not leaving the job until they're seventy-five. Look at old movies. How old was the person they considered old sitting in the corner? That person was in their sixties at, um, and at most seventy. All right? I've watched old Twilight Zone episodes, black and white from the fifties and sixties. And the old person, the really old person in the nursing home is seventy-two. So, all I'm saying is, if fifty years ago you used to be given up for dead at seventy-two, and now you can go to eighty-five, um, if you're thirty-seven, you've got at least another forty years. That takes you to seventy-seven. Forty years!

• 45:29Neil deGrasse Tyson?

  Forty years. Look what people do between high school and graduate school to get advanced degrees. They do that and then they're on the market by the time they're 30. You've got plenty of years to do this. Just do it. Don't let anybody stop you. And we'll welcome you on the other side.

• 45:46Chuck Nice?

  Wow.

• 45:47Neil deGrasse Tyson?

  Chuck, we've got to call it quits there.

• 45:48Chuck Nice?

  All right. So much fun.

• 45:50Neil deGrasse Tyson?

  All right. Thanks Chuck. This is StarTalk, Cosmic Aquarius Patreon edition. Neil deGrasse Tyson, keep ripping up.