Things You Thought You Knew - A Constellation Prize

How did Uranus get its name? Neil deGrasse Tyson and comic co-host Chuck Nice explain all the things you thought you knew about the names of the planets and moons in our solar system, the formation of the moon, and the constellations.

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. This is StarTalk. Neil deGrasse Tyson here, your personal astrophysicist. And today's show is gonna be things you thought you knew. And old timers out there know there's only one person I'd do that with, and that's Chuck Nice.

• 0:31Chuck Nice?

  Yes.

• 0:32Neil deGrasse Tyson?

  Always good to have you, man.

• 0:33Chuck Nice?

  Always.

• 0:34Neil deGrasse Tyson?

  Alright, so you ready to have things you thought you knew explained?

• 0:37Chuck Nice?

  Yes, because we could do millions of these. If the criteria is, I don't know.

• 0:47Neil deGrasse Tyson?

  You've future-proofed this.

• 0:53Chuck Nice?

  That's right. There will be no shortage of topics, my friend.

• 0:59Neil deGrasse Tyson?

  Alright, let's get to this. I occasionally get questions about naming of things in my field. Alright, and let's take, for example, the names of the moon, of planets and their moons. Alright? Had you ever wondered how we get these names?

• 1:20Chuck Nice?

  Not really, but I, I mean, I figured somebody looked up and said, "I'm gonna call it that."

• 1:27Neil deGrasse Tyson?

  Somebody did.

• 1:28Chuck Nice?

  Right, because for me, it'd have been like, you know, Jupiter, and then Jupiter A, B, C, D, you know, Jupiter 1, Jupiter 2, Jupiter...

• 1:38Neil deGrasse Tyson?

  Yeah. That's because you have no imagination, right there.

• 1:41Chuck Nice?

  Well, that goes without saying.

• 1:43Neil deGrasse Tyson?

  So here we go. So the planets are named, they all have Roman Latin names, basically.

• 1:50Chuck Nice?

  Right.

• 1:51Neil deGrasse Tyson?

  Okay? And so they're named after sort of Roman gods. You have Mercury, you know, the messenger god. Mercury's the fastest moving planet. Venus is quite beautiful in the evening sky. That object got named for Venus, the goddess of love and beauty. And then also in the sky, you have Mars, which is red, the color of blood. So the warrior god got named after that planet. Or that planet got named after the warrior god. And let's keep going. You have Jupiter, Saturn...

• 2:24Neil deGrasse Tyson?

  And those are the planets known to the ancients. And then later would be discovered Neptune, Uranus and Neptune. And the thing about Uranus was, it was the first

• 2:36Chuck Nice?

  Both down under.

• 2:38Neil deGrasse Tyson?

  It was the first time anyone discovered a planet. It was William Herschel, back in the seventeen hundreds. And it was like, all the other planets were just known because they're just in the sky. There's not the person who discovered them. Anyone who looked up noticed them. So no one is on record for discovering Mercury, Venus, Mars, Jupiter or Saturn.

• 3:02Chuck Nice?

  Right.

• 3:02Neil deGrasse Tyson?

  But Uranus got discovered and it got discovered by William Herschel.

• 3:08Neil deGrasse Tyson?

  And no one had discovered and therefore no one had actually named a planet in modern times.

• 3:14Chuck Nice?

  Well, he picked a good one.

• 3:16Neil deGrasse Tyson?

  He tried to figure out what to name it. And so, so he did the right thing, okay? He named it after his principal funder. That's what scientists do.

• 3:27Chuck Nice?

  Wow.

• 3:28Neil deGrasse Tyson?

  Artists do the same thing. They draw in the, in the, in the background, the, the benefactor or whatever, you know, the sponsor of the painting. It makes the, the rich folks feel good.

• 3:39Chuck Nice?

  Right.

• 3:39Neil deGrasse Tyson?

  So, so he, he named this new star after King George.

• 3:45Chuck Nice?

  Okay, alright.

• 3:46Neil deGrasse Tyson?

  No, that's the King George, that's of the American Revolution, that same King George. Because this is the late eighteen, late seventeen hundreds. And so that's the same George that John Hancock signed his big signature, large enough for him to read.

• 4:00Chuck Nice?

  The same George in Hamilton?

• 4:02Neil deGrasse Tyson?

  That same George, that's correct. That same King George.

• 4:05Chuck Nice?

  Oh, by the way, that King George, God, could, he was a show stealer.

• 4:12Neil deGrasse Tyson?

  He was good.

• 4:14Chuck Nice?

  So I'm trying to figure out where Uranus. Comes from King George.

• 4:19Neil deGrasse Tyson?

  Oh, no, I'm getting there. Yeah, yeah, give me, give me a second. These are explainer videos. That's the whole point.

• 4:24Chuck Nice?

  There you go.

• 4:26Neil deGrasse Tyson?

  So I have books from that period. So late 1700s, early 1800s, where the, the enumeration of planets is very clear. It's, but we know Earth is a planet, right? So Mercury, Venus, Earth. That since Copernicus, we knew that Earth is a planet as an object that goes around the sun. So we have Mercury, Venus, Earth, Mars, Jupiter, Saturn.

• 4:51Chuck Nice?

  George.

• 4:52Neil deGrasse Tyson?

  And George.

• 4:53Chuck Nice?

  Of course.

• 4:56Neil deGrasse Tyson?

  And George.

• 4:57Chuck Nice?

  Yes.

• 4:57Neil deGrasse Tyson?

  I have books that list the planets in that order with those names. And this was, you look back and say, what the, but what, what? You know, and so, so.

• 5:10Chuck Nice?

  God, we should have left that. Oh, I'm telling you right now, that would be the best thing in the world. One day, we are going to get to George.

• 5:23Neil deGrasse Tyson?

  With our greatest of technologies.

• 5:24Chuck Nice?

  Technology. We shall one day set foot upon George.

• 5:34Neil deGrasse Tyson?

  So.

• 5:35Chuck Nice?

  Or we could have just, instead of Uranus, I'm sorry, Uranus, we could have went with George's ass.

• 5:48Chuck Nice?

  Planet, oh my, oh, Planet George's ass.

• 5:54Neil deGrasse Tyson?

  You're gonna say it with a British accent.

• 5:56Chuck Nice?

  Exactly. Planet George's ass. Hmm. Arse, I'm sorry. I'm terribly sorry. I say, one day we shall get to George's arse. I say.

• 6:08Neil deGrasse Tyson?

  Old chap.

• 6:09Chuck Nice?

  One day we'll get there. So looking forward to being firmly planted in George's ass.

• 6:18Neil deGrasse Tyson?

  Okay, stop, that's enough.

• 6:23Neil deGrasse Tyson?

  Oh no, oh no, oh no, no, no, no, no, okay. Okay, so, it would take a little while, but clearer heads would prevail. Alright. And how do you tell the discoverer of a planet that he has to unnamed it after his king? This is very tentative. That's sensitive. Diplomatic moments here. And so, finally, we landed on Uranus, Uranus, which, from what I have read, is similarly pronounced in, in both Greek and, and Latin, and Roman.

• 7:01Neil deGrasse Tyson?

  It, they, it's the same word, alright? So it's actually a crossover name between the, the Roman and the Greek. That's cool. Okay? So that, I'll show up later in a minute. So, so, and after that, we get to Neptune, that is a, you know, Roman god of the seas and this sort of thing. And then when Pluto was discovered, when everyone believed it was a planet, that Pluto is the god of the underworld and it's Roman. So, there you have it. Alright, so, you might say, well, what about the Greeks? In the Western traditions, they were pretty significant in what they contributed to all of this. It's not just the Romans. Romans are like Johnny come lately compared to the Greeks. And so, we said, okay, in our Western astronomical traditions, we will honor,

• 7:46Neil deGrasse Tyson?

  not only the Romans with planet names, we will honor the Greeks with moon names. Ah ha! Okay. There we go. So, all moons, essentially, alright, there's some exceptions here I can get to. All moons in the solar system are named after Greek characters.

• 8:11Neil deGrasse Tyson?

  In the life of the Greek counterpart to the Roman god after whom the planet is named.

• 8:20Chuck Nice?

  Gotcha. That's

• 8:22Neil deGrasse Tyson?

  Are you with me on that?

• 8:23Chuck Nice?

  So basically, you take the Roman, right? You find a god and then you say, okay, how's that translate into a Greek god? And now we got a name for a moon. I mean,

• 8:36Neil deGrasse Tyson?

  No.

• 8:36Chuck Nice?

  Right.

• 8:36Neil deGrasse Tyson?

  No.

• 8:37Chuck Nice?

  Go ahead.

• 8:37Neil deGrasse Tyson?

  No, no, no, no, no. You got, you got, you got

• 8:40Chuck Nice?

  Almost, okay.

• 8:41Neil deGrasse Tyson?

  So you got the Roman god. Ask, what is the Greek god counterpart to that Roman god?

• 8:48Chuck Nice?

  Okay.

• 8:48Neil deGrasse Tyson?

  Now you look at characters in the life of the Greek god.

• 8:53Chuck Nice?

  Gotcha. So you don't

• 8:55Neil deGrasse Tyson?

  And those are the names of the moons.

• 8:56Chuck Nice?

  Otherwise, you would end up with just two gods on different sides of the coin. Right. And who is the lesser?

• 9:04Neil deGrasse Tyson?

  Yeah, but one would be a planet, one would be a moon, and that wouldn't be right.

• 9:07Chuck Nice?

  Right.

• 9:07Neil deGrasse Tyson?

  Yeah, you'd be pissing off some powerful god. So let me give you a list of some of these moons. Mercury doesn't have any moons and neither does Venus. Okay? And let's skip over Earth for a moment. We'll get back to Earth. So what's next? Mars. Mars has two moons. And they're, they're pretty sorry moons. Just they're like a dozen miles across. They're not even spherical. They're, they're embarrassments, basically. Yeah, people wondering whether they were just captured asteroids.

• 9:38Chuck Nice?

  That sounds like a rock that just happened to

• 9:40Neil deGrasse Tyson?

  Yeah, it's a rock.

• 9:41Chuck Nice?

  It doesn't really sound like a moon. It sounds like a rock that got lost.

• 9:45Neil deGrasse Tyson?

  Yeah. A wayward rock. Somebody lost a rock.

• 9:52Neil deGrasse Tyson?

  So, so the Martian moons are called Phobos and Demos.

• 9:58Chuck Nice?

  Phobos and Demos.

• 10:00Neil deGrasse Tyson?

  Yes, Phobos and Demos. As I have read in the, in the, in the Greek traditions, that's the name of the, each of the two horses. That drives the chariot of Mars across the sky.

• 10:14Chuck Nice?

  Phobos and Demos, which by the way, Demos is a really cool name, so.

• 10:19Neil deGrasse Tyson?

  Demos, yeah, yeah.

• 10:20Chuck Nice?

  Waste, wasted on a rock.

• 10:23Neil deGrasse Tyson?

  It is.

• 10:24Chuck Nice?

  As cool of a name as Demos is, you wasted it on a rock.

• 10:28Neil deGrasse Tyson?

  Yeah, it looks like an Idaho potato. It's embarrassing. It's embarrassing, but it's all it's got. So in fact, uh, one of the, uh, Mars rovers, I forgot which, was in the path of a Phobos or Demo, uh, Phobos eclipse, right? And so, so it's got a picture of Phobos passing in front of the sun and it's just this outline of an Idaho potato, deep within the full disk of the sun. It's embarrassing.

• 10:54Chuck Nice?

  Yeah.

• 10:55Neil deGrasse Tyson?

  It was like, it couldn't even cover the whole sun because it's so little and it's not even round. So anyhow, let's keep going. So what comes after Mars, we get to Jupiter.

• 11:07Neil deGrasse Tyson?

  So, uh, Jupiter, it's four brightest moons were named, they're called the Galilean moons. Galileo first saw them through his telescope and then described them. But this is, uh, let me remember, we have, uh, Io, Callisto, Ganymede, and Europa. Those are the four biggest moons of Jupiter's, I lost count, is probably nearing somewhere around a hundred moons or more, because every time we get closer to it, we see other tiny little rocks. And what distinguishes a moon from just like a knot moon, you know, if it's just, if it's orbiting and it's bigger than a dust particle, is it a moon? Can you be in moon no matter how little you are? This is a debate and I'm not going to bring that up here.

• 11:49Neil deGrasse Tyson?

  But I'm just going to say, those are the four big ones and those are the ones that kind of really matter. When you, when you see Jupiter through a telescope, there they are, okay? And there's four of them and then they just, they go around Jupiter. And Galileo, when he first saw them, he said, oh, there are stars near Jupiter. And then he looked later on and he says, wait, the stars have moved, moved. He called them the Ga, the, the, the Jupiter stars, right? And because why, why would you think you're discovering a moon? This isn't, you, you're coming out of, out of nowhere and landing on this information. And so he was able to see that they moved around, they orbited Jupiter. Oh my gosh, that meant the Earth was not the center of all motion.

• 12:32Chuck Nice?

  Yeah.

• 12:32Neil deGrasse Tyson?

  This, this was devastating to people who wished it were otherwise.

• 12:36Chuck Nice?

  Jupiter's Star is sounds like a really bad basketball team.

• 12:40Neil deGrasse Tyson?

  Jupiter's Star.

• 12:41Chuck Nice?

  Really, it does.

• 12:44Neil deGrasse Tyson?

  It was, it's a bad any kind of team, right? Bad soccer team, right? So now let me take you to Uranus.

• 12:51Chuck Nice?

  Right.

• 12:52Neil deGrasse Tyson?

  Okay. There was a pact.

• 12:57Neil deGrasse Tyson?

  So as not to piss off the Brits, who are very powerful in the late 1700s. Okay. All right, there's one of the most powerful forces the world had ever seen. Particularly with their naval power. Okay. So. You're gonna piss off the Brits and King George? What are you gonna do? So here's what they did. Here's what they did. We said, okay, we will make an exception of the Greek rule. For the planet Uranus. And we will name the moons of Uranus. After fictional characters.

• 13:33Neil deGrasse Tyson?

  In the plays of Shakespeare.

• 13:35Chuck Nice?

  Oh. Okay, I have never heard this ever.

• 13:40Neil deGrasse Tyson?

  So this threw a bone back to the Brits. So that they could rest easily that their king was stripped from the name of the planet. And it had, and it became a Roman god.

• 13:54Chuck Nice?

  Uh, wait a minute, a constellation prize. Sorry.

• 13:58Neil deGrasse Tyson?

  No.

• 13:59Chuck Nice?

  Oh, God. Yeah.

• 14:02Neil deGrasse Tyson?

  Chuck, that was good. Chuck, that was good.

• 14:05Chuck Nice?

  I sailed back.

• 14:06Neil deGrasse Tyson?

  I gotta hand it. I gotta hand it to you. So. What are some names? We have Portia, P O R T I A. Remember Portia from your Shakespeare? Um, there are a lot of characters from A Midsummer's Night Dream, because that's a very, quite a fantastical. Storytelling going on there. Uh, among the moon names, we have, uh, Umbrio. Okay, Titania.

• 14:28Neil deGrasse Tyson?

  Miranda? Miranda is the lead character in The Tempest. Okay, we have Ariel, Oberon.

• 14:34Chuck Nice?

  Oberon.

• 14:34Neil deGrasse Tyson?

  All right, so Puck.

• 14:35Chuck Nice?

  Oh.

• 14:36Neil deGrasse Tyson?

  Puck, Desdemona. All, all these moons have names drawn from Shakespeare.

• 14:42Chuck Nice?

  No, that is, that is really stunning. Cause I mean, I can't believe that that's just something that everybody should know. Cause it's so like, almost, it feels so random.

• 14:57Neil deGrasse Tyson?

  Well, it's a little bit of history. And it's fun history. It's not science so much as it is just.

• 15:02Chuck Nice?

  No.

• 15:02Neil deGrasse Tyson?

  It's, it's the intersection of science taking place embedded in our culture.

• 15:07Chuck Nice?

  Yeah.

• 15:08Neil deGrasse Tyson?

  Yeah. So now you go out to the outer planets. By the way, Pluto, the first moon was discovered around Pluto. It was named Sharon, or I think in the Greek is Karen. Uh, and Karen is the ferry boat driver who carries your soul across the river Styx to Hades.

• 15:24Chuck Nice?

  Pluto, god of the underworld.

• 15:26Neil deGrasse Tyson?

  Well, yeah, it's what it's Hades. That's the, so you go to the Greek side of that. So make a, a long story short, so this is the, the, the origin stories of the names of the moons. And in the very later years, when there are many more moons discovered and you run out of incidental characters in the life of Greek and Roman gods. By the way, we had many because they led complex and interesting social lives. Right? So there's a lot of characters you could draw from. But in modern times, a more inclusive sensibility has descended upon us. And so now there are, there are, there are names of, of, of gods and other, other spiritual beings, fictional beings in, from other cultures, not just Greek and Roman.

• 16:10Neil deGrasse Tyson?

  When we fully flesh out all the names of all the moons. So that's a, that's a, that's, that's solar system moons 101.

• 16:17Chuck Nice?

  Oh man, that's, I'm telling you, that was really cool. Uh, however, from now on, I'm sorry, I, I have to call Uranus George's ass. That's.

• 16:31Chuck Nice?

  That's it.

• 16:33Neil deGrasse Tyson?

  Chuck, we gotta take a quick break, but when we come back, guess what? I have more explaining to do.

• 16:39Chuck Nice?

  Excellent.

• 16:41Neil deGrasse Tyson?

  All right, when StarTalk returns.

• 16:49Speaker 02

  I'm Joel Cherico and I make pottery. You can see my pottery on my website, cosmicmugs.com. Cosmic Mugs, art that lets you taste the universe every day. And I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 17:15Neil deGrasse Tyson?

  Chuck, we're back. We're gonna take a look at the moon. We looked at the moon a lot lately, but we're not done. I'm not finished with it. Okay, can you handle it?

• 17:29Chuck Nice?

  Oh, yes. No.

• 17:33Neil deGrasse Tyson?

  Maybe.

• 17:35Neil deGrasse Tyson?

  All right.

• 17:36Chuck Nice?

  The moon is so mysterious for so many people for so many reasons. And it's so, I mean, and it's so romantic.

• 17:44Neil deGrasse Tyson?

  Yes, it's all the above. It's spooky and romantic.

• 17:48Chuck Nice?

  Romantic, it's poetic in many respects. You know, it's in so many paintings, like, you know.

• 17:56Neil deGrasse Tyson?

  Yeah, and it's a fundamental part of the symbol for Islam. There's a crescent moon with Venus in the sky next to it. So, yeah, the moon is important.

• 18:08Chuck Nice?

  Yeah, very much.

• 18:08Neil deGrasse Tyson?

  And so a couple of things.

• 18:11Chuck Nice?

  I did not know that was Venus in that.

• 18:13Neil deGrasse Tyson?

  Well, okay, it's an evening or morning star.

• 18:16Chuck Nice?

  Which would be.

• 18:17Neil deGrasse Tyson?

  And if it's bright, it's generally gonna be Venus. But the, um, it's rare that there's another really cool star next to it. And Venus is always in the sky, either with the waning crescent or the waxing crescent. So typically that's Venus in practice.

• 18:33Chuck Nice?

  And by the way, it's really cool to see it when it's a certain time of night and it really isn't quite like all the way dark and it's so bright.

• 18:43Neil deGrasse Tyson?

  It's called twilight, Chuck. Use the word.

• 18:49Neil deGrasse Tyson?

  What do you call it when it's night but not quite dark? Did I just invent something?

• 18:57Chuck Nice?

  Oh, man. And you know, there's this stuff around us at all times that, you know, it goes in your lungs and you push it out.

• 19:07Chuck Nice?

  And that big yellow ball that gives us light, that thing?

• 19:12Neil deGrasse Tyson?

  Chuck, I'm so glad you woke up today.

• 19:16Neil deGrasse Tyson?

  Out of your forty year coma, yes.

• 19:18Chuck Nice?

  Yes, but twilight, Venus at twilight is, I mean, and you can see it with the naked eye. And it's like, it really looks like somebody turned on a light in the sky. It's really nice.

• 19:29Neil deGrasse Tyson?

  Yeah, yeah. And a little known fact, because Venus orbits the sun closer than we orbit the sun.

• 19:35Chuck Nice?

  Okay.

• 19:37Neil deGrasse Tyson?

  Venus will never stray too far away from wherever the sun is on the sky. It's not going to end up behind us with the sun in front of us. It's going to be near the sun. So that's why you'll typically notice Venus just after sunset in twilight or just before sunrise. And so in evening twilight to dusk. And then the poetic other side of that would be dawn.

• 20:06Chuck Nice?

  Cool.

• 20:08Neil deGrasse Tyson?

  Yeah. Okay. That's the crescent moon. That's cool. So more about the moon.

• 20:13Neil deGrasse Tyson?

  All evidence suggests and all theoretical understanding of the formation of the moon, helped, by the way, by rocks we brought back by the Apollo program to study and look at, we get a sense of the origin of that place.

• 20:25Chuck Nice?

  That tells us that the moon was formed. That's when America was great, remember? When we did stuff, you know, because we didn't mind our tax dollars being used to make us the greatest nation on earth. I'm just saying. Yeah, you know, but go ahead. So we brought back rocks and we were able to find out about the origin.

• 20:47Neil deGrasse Tyson?

  Analyze them and we realized that the moon doesn't have much iron in it. And an object that size should have much more iron in it than it does. So how do you make a whole object that has hardly any iron? So you make it out of a collision with Earth, but it sideswipes Earth after Earth has already sunk its iron to its core.

• 21:10Chuck Nice?

  Right. So that.

• 21:11Neil deGrasse Tyson?

  So when Earth was molten, heavy stuff falls to the middle, light stuff floats to the top. Compared to iron, rocks are light. So all the rocks floated and the iron sunk. Iron, nickel, gold, cadmium, all the the heavy elements, they're down in the core. Okay, so now Earth has pre-sifted the elements. Pre-sifted. Now you have a a Mars-sized impactor that sideswipes the Earth, scattering Earth's crust into a ring around the Earth. That Mars-sized impactor keeps going, but the debris mess that it left continues to orbit the Earth.

• 21:51Neil deGrasse Tyson?

  And the slightly larger bits of this have more gravity than the slightly smaller bits. So they'll attract more objects and they get bigger. And as they get bigger, they have even more gravity and they get even bigger and bigger. And it's a runaway exponential growth. The big get bigger and the little ones get... Eaten, thank you. So, we think over not much time, a matter of months, if not only just a few years, Earth had a ring, not much unlike Saturn, and that ring coalesced into the moon. And that moon was 20 times closer in the sky than it is today.

• 22:36Chuck Nice?

  Wow. Well, that must have looked beautiful.

• 22:39Neil deGrasse Tyson?

  Yeah, so imagine that. Just imagine that. It's 20 times wider. Imagine like moonrise.

• 22:45Chuck Nice?

  That's very Star Wars, you know, like you're standing there in the desert and you see like, you know, a giant celestial body in the sky.

• 22:56Neil deGrasse Tyson?

  And you need music to go with that, and that would just totally complete the scene. So, it turns out tidal forces are very sensitive to distance.

• 23:10Neil deGrasse Tyson?

  Very sensitive. In other words, not emotionally sensitive.

• 23:14Speaker 03

  That would be good, too.

• 23:14Neil deGrasse Tyson?

  But if you change the distance by a little bit, it'll have a big, a much bigger effect than you'd otherwise think on the strength of the tides.

• 23:22Speaker 03

  Okay, now I can't get over thinking about emotionally sensitive tidal forces. Where all of our oceans are just like, where you go? What did I do? What did I do? You said it's you, it's not me, but no, seriously.

• 23:40Neil deGrasse Tyson?

  Did I deserve this?

• 23:42Speaker 03

  You just go and throw away everything we had. As you slowly drift away. You're so distant. I don't understand. Why we don't communicate anymore? All we had to do was talk. Why are you so distant?

• 24:03Neil deGrasse Tyson?

  There's a space between us.

• 24:06Speaker 03

  I don't know how to fill this chasm between us. I can't do all the work here, okay? I'm Earth and I can't do all the work.

• 24:18Neil deGrasse Tyson?

  Chuck, how many hours of therapy have you been in with your wife?

• 24:25Speaker 03

  Oh, God. By the way, I'm the one saying that in therapy, not her.

• 24:34Neil deGrasse Tyson?

  So, so, so, so mathematically, because you can be mathematically sensitive.

• 24:39Speaker 03

  Right.

• 24:40Neil deGrasse Tyson?

  I just want to broaden your use of the term sensitivity. So, the moon, the mathematical sensitivity of tidal forces goes as the cube of the distance.

• 24:52Speaker 03

  Oh, sweet. That's a lot.

• 24:55Neil deGrasse Tyson?

  So, in other words, if it just went as the distance, okay? If it was like 20 times closer, then the tides would be like 20 times higher than they are today. But no, does it go as the distance squared? That would mean the tides would be 20 times 20 higher than, than today. What's 20 times 20?

• 25:16Speaker 03

  I don't know, 400?

• 25:22Neil deGrasse Tyson?

  Don't you pull out a calculator. You on this show, you gonna tell me what 20 times 20 is.

• 25:29Chuck Nice?

  No, I'm not doing it.

• 25:32Neil deGrasse Tyson?

  Okay, you got 400. However, tidal forces go as the cube of the distance.

• 25:43Neil deGrasse Tyson?

  So, back when the moon formed, and it's 20 times closer than it is today. So, it goes as the cube. So, the cube is, you've multiplied by itself three times. So, 20 times 20, that's 400, times another 20. So, 400 times 20, that gets you 8,000. So, the tides, the oceanic tides on Earth, raised by the moon when the moon first formed, were 8,000 times higher than they are today.

• 26:21Chuck Nice?

  Look at that. And, and, and, and, and look at that. We're trying to get back there with, with global warming. That's wonderful.

• 26:28Neil deGrasse Tyson?

  That's a different problem. Okay, so now watch what happens. Tides sloshing on and off the shores, there's friction between the solid Earth and the moving water.

• 26:41Neil deGrasse Tyson?

  And so, Earth's rotation back then was actually faster than it is today.

• 26:47Neil deGrasse Tyson?

  Depending on how far back you, you go, you get like an 18, 20 hour day for Earth, not 24 hours. Okay? So, we have a big moon, higher tides, faster rotating Earth. But the tides are so ferocious, Earth is slowing down because of it. And in response, the moon's orbit is increasing. It is spiraling away from the Earth.

• 27:14Neil deGrasse Tyson?

  And it has been doing that ever since.

• 27:18Neil deGrasse Tyson?

  We still have sloshing of tides on the shores. Earth's rotation rate is still slowing down. The moon is still spiraling away from the, the Earth, but much slower than it once was.

• 27:29Chuck Nice?

  Why are you killing me softly? If you're gonna leave, just leave. I don't understand it.

• 27:39Neil deGrasse Tyson?

  Oh, by the way, we had tidal influence on the moon.

• 27:44Speaker 03

  Okay.

• 27:45Neil deGrasse Tyson?

  The moon at one time rotated like anybody else in the, in the, in the solar system. You see the front side, the backside, the left side, the right side? But our tidal forces on the moon slowed its rotation down until we locked it.

• 28:02Speaker 03

  Right.

• 28:03Neil deGrasse Tyson?

  We locked the moon's rotation around the earth.

• 28:06Speaker 03

  That's why I'm leaving. Because see, you only see one side of me. I'm a complex person. But it seems like, you know, when we're together, I can only show you one face.

• 28:20Neil deGrasse Tyson?

  This sounds like a TV series.

• 28:25Speaker 03

  Well, then go then. Why don't you just go? Why must you make it so torturous?

• 28:32Neil deGrasse Tyson?

  I, I've been drifting from you for all these years.

• 28:35Speaker 03

  You didn't feel me drifting away? I mean, seriously.

• 28:40Speaker 03

  Chuck, you can't make a whole.

• 28:44Neil deGrasse Tyson?

  Psycho.

• 28:44Speaker 03

  Oh, my God.

• 28:45Neil deGrasse Tyson?

  Relationships.

• 28:46Speaker 03

  Hey, you know what this show is called? As the World Turns.

• 28:57Speaker 03

  Okay.

• 28:58Neil deGrasse Tyson?

  It would be authentically, it'd be the best name show there ever was.

• 29:02Speaker 03

  Okay. Oh, God. That may be the stupidest thing I've ever done on this show.

• 29:11Speaker 03

  Okay.

• 29:12Neil deGrasse Tyson?

  So.

• 29:14Speaker 03

  All right, all right.

• 29:15Neil deGrasse Tyson?

  So anyhow, so, so the point is, we tidally locked the moon. Cause we have stronger tides on the moon than the moon has on us. And so moon just got locked. We slow down its rotation, locked in on it, it only shows one face to us. And the other face we've never seen until we orbited it with spacecraft. The moon is trying to do the same thing to us. It wants to slow us down so much that we only show one face to the moon. And the day that happens, we will be in what's called a double tidal lock.

• 29:44Speaker 03

  Nice. Excellent. That's a nice dance. I like it.

• 29:50Neil deGrasse Tyson?

  Yeah, yeah. So that's, so that's what it looks like.

• 29:53Speaker 03

  Hey, man, that's great.

• 29:57Neil deGrasse Tyson?

  That's not moon lore, that's just sort of moon facts.

• 29:59Chuck Nice?

  Hey, listen, that is, that is awesome. I mean, the moon and the earth locked in a dance as the world turns.

• 30:07Neil deGrasse Tyson?

  So I have to repeat my one perfect sentence that I've ever written in my life? May I repeat it for you? Okay. The rotating planets orbit the sun like pirouetting dancers in a cosmic ballet choreographed by the forces of gravity.

• 30:27Chuck Nice?

  Wow. Damn. You wrote that? That's...

• 30:32Neil deGrasse Tyson?

  Yeah.

• 30:34Chuck Nice?

  Okay.

• 30:35Neil deGrasse Tyson?

  All right, Chuck, we gotta take a quick break, but when we come back, some of the explaining I'm gonna do is gonna pick up on an earlier explainer video on constellations, but I only just scratched the surface. Way more to come. Stay with us.

• 31:05Neil deGrasse Tyson?

  We're back. Chuck.

• 31:06Chuck Nice?

  Yes.

• 31:07Neil deGrasse Tyson?

  We're gonna be talking about things you thought you knew about the night sky, the constellations. We're gonna pick up where we left off, cuz I wasn't done with you. Let's see if you learned anything from the first session. How many constellations are there?

• 31:20Chuck Nice?

  Forty-eight. Did I get it? No.

• 31:27Neil deGrasse Tyson?

  Chuck, I said...

• 31:29Chuck Nice?

  What?

• 31:31Neil deGrasse Tyson?

  There are as many constellations as there are keys to a piano.

• 31:33Chuck Nice?

  Oh, that's right, eighty-eight. I got half of it, right? I got the eight.

• 31:36Neil deGrasse Tyson?

  No, Teddy, that's not how that works.

• 31:38Chuck Nice?

  I got the eight, right?

• 31:43Neil deGrasse Tyson?

  If we're going to the moon and the engineer says, "I got half of it, right?"

• 31:46Chuck Nice?

  Well, you got there. I mean, you're not coming back.

• 31:49Neil deGrasse Tyson?

  As you float out of space, missing your target.

• 31:51Chuck Nice?

  You're not coming back. I got half of it, right?

• 31:54Neil deGrasse Tyson?

  All right, so we said two cool things, I think, that southern hemisphere constellations, known to indigenous people from the southern hemisphere, would be later discovered by Europeans, and when they named it, they were already deep into the industrial revolution.

• 32:09Chuck Nice?

  And they named them after...

• 32:10Neil deGrasse Tyson?

  So they started naming them not after mythical magical creatures, but after like stuff that was enabling the emergence of a new kind of...

• 32:19Chuck Nice?

  Like sexting.

• 32:21Neil deGrasse Tyson?

  Another level of civilization. There's a sextant. By the way, before the sextant was invented, which was sixty degrees of a circle. Okay? There's six of those. Six times sixty is three hundred and sixty degrees. What preceded that was an octant.

• 32:34Chuck Nice?

  Wow.

• 32:35Neil deGrasse Tyson?

  Okay? That was an eighth of three hundred and sixty degrees. The sky has a sextant and an octant.

• 32:41Chuck Nice?

  Nice.

• 32:43Neil deGrasse Tyson?

  That feels a little excessive to me. All right? You know, be happy with one, but know you want two. Two out of the eighty-eight constellations are navigational devices that are kinda the same.

• 32:53Chuck Nice?

  You can never have two.

• 32:54Neil deGrasse Tyson?

  You know?

• 32:55Chuck Nice?

  You know?

• 32:56Neil deGrasse Tyson?

  That's true.

• 32:57Chuck Nice?

  You never can't overtool anything.

• 32:59Neil deGrasse Tyson?

  All right. So a couple of things. What's in your mind the most famous constellation in the southern hemisphere?

• 33:06Chuck Nice?

  Oh, in the southern? God. See, so what I was gonna say, but that's not southern, was Big Dipper, but everybody knows that.

• 33:13Neil deGrasse Tyson?

  Yeah, it's the north.

• 33:14Chuck Nice?

  Okay, in the southern hemisphere.

• 33:16Neil deGrasse Tyson?

  Eight thousand miles off.

• 33:17Chuck Nice?

  Um, I said it was in the north.

• 33:20Neil deGrasse Tyson?

  I, no, nine out of ten people say the southern cross.

• 33:22Chuck Nice?

  I was about to say the cross, yeah.

• 33:24Neil deGrasse Tyson?

  You would not.

• 33:25Chuck Nice?

  I really was.

• 33:25Neil deGrasse Tyson?

  There's no evidence of that.

• 33:26Chuck Nice?

  Let me tell you something. I really was about to say the cross, but I was scared to do so because one night we were sitting out and you had your, you know, top secret, uh, sky pointer.

• 33:37Neil deGrasse Tyson?

  Government issue.

• 33:38Chuck Nice?

  And you were, and you, but there's a cross in the north, too. That, and so that's why I would, I was about to say cross, but I got confused.

• 33:48Neil deGrasse Tyson?

  So there's a northern cross, which we love here in the northern hemisphere, and there's a southern cross.

• 33:52Chuck Nice?

  Cool.

• 33:53Neil deGrasse Tyson?

  But they're really different from each other.

• 33:54Chuck Nice?

  Okay.

• 33:56Neil deGrasse Tyson?

  The southern cross is embarrassing compared to the northern cross.

• 34:01Chuck Nice?

  Oh, that's terrible.

• 34:01Neil deGrasse Tyson?

  The southern cross has four stars in it.

• 34:06Chuck Nice?

  Okay.

• 34:08Neil deGrasse Tyson?

  It's in the shape of a rhombus.

• 34:10Chuck Nice?

  Oh.

• 34:11Neil deGrasse Tyson?

  There is no star.

• 34:13Chuck Nice?

  There's no cross.

• 34:13Neil deGrasse Tyson?

  At the transept.

• 34:16Neil deGrasse Tyson?

  So you could have just drawn a rhombus to remind people from eighth grade geometry. A rhombus is like, take a perfect square, sit on it,

• 34:23Chuck Nice?

  Stretch it out.

• 34:24Neil deGrasse Tyson?

  distort the sides, and then you get a rhombus, okay? So, so, so it is a stretch to call the Southern Cross a cross. It's a stretch.

• 34:35Chuck Nice?

  Wow.

• 34:36Neil deGrasse Tyson?

  Not only that, of all eighty-eight constellations, the Southern Cross is the smallest.

• 34:41Chuck Nice?

  Oh.

• 34:42Neil deGrasse Tyson?

  Your thumbnail at arm's reach would completely cover all four stars of the Southern Cross.

• 34:52Neil deGrasse Tyson?

  It is one of the biggest marketing delusions there ever was.

• 34:56Chuck Nice?

  Nice. I mean, I mean.

• 34:59Neil deGrasse Tyson?

  And isn't there Crosby, Stills, uh, song? Crosby, Nash?

• 35:03Chuck Nice?

  Crosby, Stills and Nash?

• 35:04Neil deGrasse Tyson?

  The Southern Cross.

• 35:05Chuck Nice?

  Oh, okay.

• 35:05Neil deGrasse Tyson?

  That's the only one I know.

• 35:07Chuck Nice?

  Yeah, I don't know the song at all, bud.

• 35:11Neil deGrasse Tyson?

  Well, they didn't sing that in the hood?

• 35:12Chuck Nice?

  Yeah, I was gonna say CSR, that's a, you know, it's a little Caucasian for me, I'm just saying.

• 35:19Chuck Nice?

  I mean, don't get me wrong.

• 35:20Neil deGrasse Tyson?

  So.

• 35:22Neil deGrasse Tyson?

  So this, I just wanna put, put it out there with the Southern Cross. Now, have you ever met people who have visited the Southern Hemisphere anywhere? Be it Africa?

• 35:32Chuck Nice?

  Oh, yeah, many people.

• 35:33Neil deGrasse Tyson?

  Or, or Australia? A- a- and, and they come back and what do they tell you about the sky?

• 35:39Chuck Nice?

  Uh, I, you know, I never really got into it. I normally ask them about the place they were. See, that's, that's how people.

• 35:46Neil deGrasse Tyson?

  How's the clubs?

• 35:47Chuck Nice?

  Exactly. You know, tell me about the food, what did you see? You know, only you would be like, and so the night sky. Tell me, tell me more about that night sky. But go ahead, what do they say?

• 35:58Neil deGrasse Tyson?

  What happens is, people visit the Southern Hemisphere and they come back and they say, the Southern Hemisphere, Hemisphere sky is so beautiful. It is so amazing. Oh, my gosh. And, and so there's another little delusion going on there as well.

• 36:13Chuck Nice?

  And what is that?

• 36:15Neil deGrasse Tyson?

  Okay. Um, I don't want to stop you from liking the southern hemisphere sky better than the north. I have no problems with that. But there are forces operating that contaminate your data.

• 36:29Chuck Nice?

  Okay.

• 36:29Neil deGrasse Tyson?

  Okay? Do you know how much of Earth's land is in the southern hemisphere?

• 36:34Chuck Nice?

  Um, I would say not a lot. I mean, when you look at Africa, it's like, that's most of it.

• 36:41Neil deGrasse Tyson?

  Yes, okay, about fifteen percent of Earth's landmass is south of the equator.

• 36:47Chuck Nice?

  Okay, yeah.

• 36:48Neil deGrasse Tyson?

  That's also about fifteen percent of Earth's population.

• 36:52Chuck Nice?

  Uh-huh.

• 36:53Neil deGrasse Tyson?

  Okay? So hardly anybody lives in the southern hemisphere. So there's hardly any city lights, hardly any light pollution, air pollution. All the things that subtract away from our experience embracing the sky in the north does not block your view in the south. So people think the actual sky is better because they can see it better.

• 37:21Chuck Nice?

  Wow.

• 37:23Neil deGrasse Tyson?

  So I'm telling you that the north has all the coolest constellations. All right, you know, with the Big Dipper and the, you know, and the Little Dipper and the, you know, and Cassiopeia. Some constellations straddle the north and the south. Orion is half in the north and half in the south. But when we look at him, he's right side up. If you want to see Orion in the southern hemisphere, he's upside down. That there's, there's, there's no excuse for that. So I'm just, I'm a northern chauvinist here, but I think I have good reason for it.

• 37:55Chuck Nice?

  Yeah, but the, the problem is we can't see it, so.

• 38:00Chuck Nice?

  I mean, you can be as hot as you want, you know, but if you're walking around in a burlap sack.

• 38:07Neil deGrasse Tyson?

  Nobody's gonna know.

• 38:08Chuck Nice?

  Nobody knows how hot you are.

• 38:10Neil deGrasse Tyson?

  Wow, we gotta get rid of... So, yeah, so this is an interesting fact about it. Now, here's a... So, the Northern Cross is much bigger than the Southern Cross, and there's a star in the transept for it. Okay, it's called... And that's an asterism. An asterism is a set of stars that is the more interesting subset of all the stars that comprise the constellation. So, the Northern Cross is Cygnus the Swan, the constellation, which is not only those stars in the cross, but there are other stars where you can imagine wings, and it's flying long-necked swan along the Milky Way. So, it's a beautiful thought that there's a swan doing this, but it's bluntly a cross.

• 38:55Neil deGrasse Tyson?

  Now, last thing I'll tell you. There's more, but I just want to sort of put it out there. Many of the star constellations are all Greek and some latter-day technologically-related ones, but some of the earliest navigators were the Arabs. Okay, the entire Arabian Peninsula, all those folks, there are very few clouds because it's desert, and so you saw the night sky and you want to get around. There's no monuments, there's no GPS, there are no mile markers, how are you going to get around? So, they pioneered astrolabes, which was their version of the European sextant, okay, and the octant. The astrolabe, they did it first, and it's beautiful works of art with rotating dials,

• 39:40Neil deGrasse Tyson?

  and you hold it up, and you can get the angle, and there are tables and charts. It's magnificent, all etched in brass. Beautiful. We have a collection at the American Museum of Natural History, but one of the largest collections in the world is at the Adler Planetarium and Astronomy Museum in Chicago. Nice. They have one of the largest collections of astrolabes in the world. Anyhow, point is, as an homage to the Arabic role in navigating the sky, two-thirds of all stars in the sky that have names have Arabic names. This is part of the sort of inclusiveness of my field, where if you contribute to it, we're not going to forget you. Right.

• 40:24Neil deGrasse Tyson?

  You guys remember the little people, that's cool. And by the way, in the constellation Libra, the scales... Um, the two brightest stars in that constellation are Arabic names. One of them is Zubin El Janubi, the other is Zubin Es Shemali.

• 40:39Chuck Nice?

  Okay.

• 40:41Neil deGrasse Tyson?

  Those are the two longest star names of all named stars in the sky. Just putting it out there. And what is the abbreviation for pound?

• 40:50Chuck Nice?

  LBS.

• 40:52Neil deGrasse Tyson?

  LB. You know what LB stands for?

• 40:54Chuck Nice?

  Uh, uh, no, I don't.

• 40:56Neil deGrasse Tyson?

  Libra.

• 40:57Chuck Nice?

  Oh, God. It just.

• 40:59Neil deGrasse Tyson?

  The scale.

• 41:00Chuck Nice?

  Gets worse.

• 41:00Neil deGrasse Tyson?

  Okay.

• 41:02Chuck Nice?

  First you go from pounds to LB.

• 41:06Neil deGrasse Tyson?

  Right, right. And it's, and LB is a short for Libra, the scales. The measurement of things. So, so the sky is fun. We could go on and on and on, but I had, I want to get some basics out there. I Chuck, we gotta call it quits.

• 41:20Chuck Nice?

  Okay.

• 41:21Neil deGrasse Tyson?

  Have you had enough things you thought you knew explained to you?

• 41:24Chuck Nice?

  I never get enough of explaining, okay? There's things I thought I knew and I'm like, I thought I knew, but I didn't know.

• 41:31Neil deGrasse Tyson?

  Yeah. And the stuff you didn't know that you thought you knew it.

• 41:34Chuck Nice?

  Exactly.

• 41:35Neil deGrasse Tyson?

  That counts.

• 41:36Chuck Nice?

  I didn't know. I thought I knew this and now I know that I do. And then there's some stuff that I didn't want to know at all. And I, and I still know it now.

• 41:46Neil deGrasse Tyson?

  Occasionally you have to know stuff that you didn't want to know at all. That, that happens in life.

• 41:50Chuck Nice?

  That's right.

• 41:51Neil deGrasse Tyson?

  And that'll happen here on Things You Thought You Knew. Always good to have you Chuck. This has been Star Talk, a Things You Thought You Knew edition. Neil deGrasse Tyson here.

• 42:06Neil deGrasse Tyson?

  Okay, but do you know what the name of our moon is?

• 42:09Chuck Nice?

  Oh, no, the moon. How did that happen? Everybody sees great names and we, and we have moon.

• 42:16Neil deGrasse Tyson?

  Moon. No, no, it has a name. It's called Luna.

• 42:18Chuck Nice?

  Oh, that makes sense. And, and, and, and that's funny because in certain languages, they call it Luna.

• 42:23Neil deGrasse Tyson?

  Yeah, Luna. And Earth has a name.

• 42:25Chuck Nice?

  Okay, Earth.

• 42:27Neil deGrasse Tyson?

  It's called Terra.

• 42:28Chuck Nice?

  Oh, yeah. And we're called Terrans in most sci-fi films.

• 42:33Neil deGrasse Tyson?

  Oh, do I? Yes, we're called Terrans. And the sun has a name.

• 42:37Chuck Nice?

  Okay.

• 42:37Neil deGrasse Tyson?

  It's called Sol, S O L.

• 42:39Chuck Nice?

  Nice, yeah.

• 42:40Neil deGrasse Tyson?

  So if you just Latinized everything, we have Sol, Terra, and we have Luna. You got all the planets and everybody's one happy family of cultural expression and diversity.

• 42:50Chuck Nice?

  Awesome. Well. Okay, that was great.