Cosmic Queries: Lunar Geology

Why does the Moon have more craters than the Earth? What’s the Moon’s true color? Is the dark side of the Moon real? Could we terraform the Moon? Neil deGrasse Tyson, Chuck Nice, and planetary scientist Raquel Nuno answer fan questions on lunar geology.

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

• 0:01Neil deGrasse Tyson?

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

• 0:14Neil deGrasse Tyson?

  This is StarTalk Cosmic Queries Edition. Co-host Chuck Nice, Chuck. Hey Neil, what's happening? Feeling good today? Absolutely, man. So today's Cosmic Queries are, they're all based on the moon. Really? And I know a little bit about the moon, you know, a little bit. You're being modest, bro. No, no, no, I know it as an astrophysical object. Okay. I don't, I don't know. Wait a minute. What, what more is there? It's an astrophysical object. No, no, no, no. That is what you do! I, yes, however, it's also a geological object. Ah-huh! So people who think about rocks and minerals and, and... Silicates and... ...rock and all, and cratering. Yeah.

• 0:59Neil deGrasse Tyson?

  There are people who have that expertise and that's who we have on this show right now. Oh! Raquel Nunez, Raquel, welcome to StarTalk Cosmic Queries.

• 1:08Speaker 01

  Hello, it's such an honor to be here, thank you for having me.

• 1:11Neil deGrasse Tyson?

  Excellent, excellent, and so you are a doctoral candidate at UCLA and, uh, University of California, Los Angeles. Yeah. That's what that stands for, and... How much does your mother pay somebody that gets you in there?

• 1:29Neil deGrasse Tyson?

  What, what is your mom, what sport does your mom lie about this? UCLA was on the list. My daughter Raquel, she's an archer!

• 1:43Neil deGrasse Tyson?

  So, okay, well, I guess we'll find out, Chuck, how good an expertise she actually has. So you're, you're in the Department of Earth and Planetary Sciences?

• 1:52Speaker 01

  Mm-hmm.

• 1:53Neil deGrasse Tyson?

  Excellent, and you're a doctoral candidate, so we expect your PhD in, within a couple of years, perhaps?

• 2:00Speaker 01

  Hopefully within the next year, my, my advisor told me he wants me out by June, so...

• 2:05Neil deGrasse Tyson?

  Oh yeah, well that works.

• 2:08Neil deGrasse Tyson?

  Yeah, yeah.

• 2:08Speaker 01

  I keep having babies during grad school, so it's delayed the process a little bit, but I think he's like, "You're ready." Just, just.

• 2:15Neil deGrasse Tyson?

  Well, if you have babies during graduate school and you successfully graduate graduate school.

• 2:19Chuck Nice?

  That's it.

• 2:20Neil deGrasse Tyson?

  And you got that done.

• 2:21Chuck Nice?

  Right.

• 2:21Neil deGrasse Tyson?

  And now you.

• 2:22Chuck Nice?

  By the way, you get something called "degree plus."

• 2:27Neil deGrasse Tyson?

  That's right. It's gotta be some.

• 2:29Chuck Nice?

  Yeah, you get extra. You get a P- you get a PhD plus.

• 2:35Neil deGrasse Tyson?

  There's Disney plus.

• 2:36Chuck Nice?

  Yes, right, exactly.

• 2:39Neil deGrasse Tyson?

  Well, congratulations on pulling all that off. And, but just in particular, you know, to the astrophysicist and to the biologist, the moon is just kind of a dead place. And it's, and it's, you know, it's just, there's no color. It's, and, and yet, this is the subject of your PhD thesis. So what's up with that? What do you see that we don't see?

• 3:02Speaker 01

  So it is my goal to change your mind with this.

• 3:04Neil deGrasse Tyson?

  Yeah, thank you.

• 3:05Speaker 01

  Cosmic query episode.

• 3:07Chuck Nice?

  Nice.

• 3:09Speaker 01

  So it actually turns out that we don't know very much about the moon. We know something, but we still don't know how it formed. We think we know, but it's not a solved case. And so what's really interesting to me is I've always looked at the moon, you know, we see it. And when we go at night, we see the moon and it's beautiful. So it's always been a thing for me to appreciate. And I think that's what's so appealing for me, the moon, is that I've seen it ever since I was a child and just wonder like, "What is it? Is there, are there beings on there?" But of course, there's not. There's, there's no life on the moon. But it's, it's something that has been with the earth since the, almost since the beginning of the earth.

• 3:54Speaker 01

  So everything that the earth has experienced, essentially the moon has witnessed. And I like to think of the moon as a witness plate to what has happened here on earth.

• 4:04Neil deGrasse Tyson?

  Chuck, Chuck, can I, can I get a witness?

• 4:06Chuck Nice?

  Yes, right. Hello, I'm the moon. I like to watch.

• 4:15Neil deGrasse Tyson?

  So, so Raquel, you make a fascinating sort of point of scientific romance where you have an object of interest that you study, and when you go home, there it is in the sky.

• 4:26Chuck Nice?

  Oh, yeah.

• 4:27Neil deGrasse Tyson?

  Just, and it's there to remind you to come back the next day, I guess. Because so much of science involves things you can't see, it's too far away, you need a big telescope, and you have it right there as this daily poke.

• 4:42Chuck Nice?

  And it's the only place where we've actually been.

• 4:45Neil deGrasse Tyson?

  Yeah.

• 4:46Chuck Nice?

  You know, so...

• 4:47Neil deGrasse Tyson?

  But even so, we hardly know hardly anything. We, we, we've landed in six spots on the, imagine landing in six spots on Earth and saying, "Yeah, I got Earth, we got Earth all sewn up."

• 4:58Chuck Nice?

  Yeah, but I'm just saying, like, it's, it's, it's kind of cool that we can go there. Like, I'm surprised that we haven't gone back more and more to find out more.

• 5:07Neil deGrasse Tyson?

  The thing that we can go there is that we once went there. We don't know how to go there today. We got nothing that'll get us there.

• 5:13Chuck Nice?

  So, are you serious?

• 5:15Neil deGrasse Tyson?

  Yes, dude.

• 5:17Chuck Nice?

  Come on. We can't, we can't go to the moon today.

• 5:21Speaker 01

  No.

• 5:22Neil deGrasse Tyson?

  That's why, for most of the last 40 years, the comment, "We can go to the moon, but we can, we can put a man on the moon, we can't," and the answer is, "We actually can't any longer put a man on the moon."

• 5:31Chuck Nice?

  Damn.

• 5:32Neil deGrasse Tyson?

  Yeah.

• 5:33Chuck Nice?

  Okay, this, this show has depressed the hell out of me.

• 5:36Neil deGrasse Tyson?

  Okay, well, Raquel is here to sort of, to brighten our day.

• 5:41Chuck Nice?

  Right, exactly.

• 5:42Neil deGrasse Tyson?

  Figure out what's going on.

• 5:43Chuck Nice?

  Well, the first...

• 5:44Neil deGrasse Tyson?

  You've got the questions. Raquel, we solicit questions from our fanbase.

• 5:46Chuck Nice?

  Yep.

• 5:47Neil deGrasse Tyson?

  On our social media platforms. Chuck has them. I haven't seen them.

• 5:50Chuck Nice?

  Nope.

• 5:51Neil deGrasse Tyson?

  So what do you have, Chuck?

• 5:52Chuck Nice?

  So let's get to it. Let's start off with Patreon, and we always start with a Patreon patron, because they give us money.

• 5:58Neil deGrasse Tyson?

  They pay.

• 5:59Chuck Nice?

  That's right.

• 6:00Neil deGrasse Tyson?

  Pushes them to the front of the line.

• 6:01Chuck Nice?

  There you go. Thanks, guys, because that's the American way. There you go. Um, this is Trace, Tracy Scrubett, and she says, "What is the most surprising thing we've discovered from studying the moon rocks and samples that we brought back from the moon? Also, have there been any unmanned missions to collect more samples?"

• 6:28Speaker 01

  I will answer that second question because it'll be quick. Yes, there have been uncrewed samples collected from the moon by USSR. They brought back, I think it was about a pound of rocks and dust from the moon.

• 6:43Neil deGrasse Tyson?

  A pound moon weight or a pound earth weight?

• 6:49Chuck Nice?

  I see what you did there.

• 6:50Neil deGrasse Tyson?

  You see what I see?

• 6:51Chuck Nice?

  I see what you did there.

• 6:54Speaker 01

  Whereas the Apollo missions brought back, I think it was around 900 pounds of rock. So the Soviet Union brought back a very small amount. But if you actually, if you go online and try to buy moon dust, so you can't buy and you can't sell Apollo moon rocks and dust, it's illegal. But you can buy the Soviet collected moon dust and rocks on the web somewhere.

• 7:21Chuck Nice?

  Of course you can.

• 7:22Neil deGrasse Tyson?

  Russian moon dust.

• 7:23Chuck Nice?

  You know, if you have enough money, you can also buy a nuclear warhead from Russia.

• 7:32Neil deGrasse Tyson?

  Okay, if that's interesting, so it's had a sample return mission. I didn't know that.

• 7:35Speaker 01

  Yeah. Now for the first question, what was it? It was what was the most surprising and interesting?

• 7:40Chuck Nice?

  Right, from studying moon rocks and samples, what did we learn that was absolutely shocking?

• 7:45Speaker 01

  So we had no idea how the moon formed at the time. There's a famous scientist, Yuri, who, his idea and a lot of people believe that.

• 7:56Neil deGrasse Tyson?

  I bet he was a Russian scientist.

• 8:00Neil deGrasse Tyson?

  See, see how smart I am? Figured that out. Let me, let me just think. He's a Russian son. Yuri, yes, okay. So what did Yuri say?

• 8:07Speaker 01

  But he believed that the moon was a very ancient, like it was made up of primordial dust and rock from the beginning of the solar system. So he thought that just these rocks had kind of stuck together and ended up here on the moon. So that nothing had ever happened to the moon. It just a bunch of pile of rock from beginning of the solar system stuck together. And this was actually kind of good because people wanted to go to the moon to collect a sample of what the solar system started out to be.

• 8:42Neil deGrasse Tyson?

  And why can't we do that on Earth? Because presumably we formed at the same time.

• 8:45Speaker 01

  We did, but what has happened is we have melted. We have been completely reprocessed. Our surface of the Earth has been completely reprocessed. So that's why when we collect certain types of meteorites, they're called chondrites, we're very excited because that is made up of the primordial dust and particles from the beginning of the solar system. So we can learn about what it looked like when this all started out.

• 9:13Neil deGrasse Tyson?

  Because Earth is geologically active.

• 9:15Speaker 01

  That's right.

• 9:16Neil deGrasse Tyson?

  It contaminates the purity of what you see.

• 9:18Speaker 01

  You change it. It becomes different minerals. It becomes, yeah, completely different. And so we thought that the moon was just this gigantic piece of primordial dust and rock. And when the Apollo astronauts went there to collect their rocks, it turned out that the moon has had an incredible geologic history. It has melted. The moon was at some point completely melted. It was covered in magma, magma ocean, that's what we call it. And differentiated, and it ended up differentiated. So the heavy stuff sunk to the bottom, forming an iron core. And then the light material, the light minerals and rocks floated to the surface, and that's what you see.

• 10:03Neil deGrasse Tyson?

  What's the difference between magma and lava?

• 10:04Speaker 01

  Okay, so magma is lava that hasn't erupted out of its source.

• 10:12Neil deGrasse Tyson?

  So you have a different word for where you find the stuff?

• 10:15Speaker 01

  Right, so if it comes out of the surface and becomes lava, if it's still trapped underneath and melted, then it's magma. That's what we call it.

• 10:25Chuck Nice?

  So whatever geological thing it is, once it gives birth, now it gives birth to lava.

• 10:32Speaker 01

  Yes, so it goes from being a fetus to a baby.

• 10:35Chuck Nice?

  The fetus is magma.

• 10:36Speaker 01

  That's right.

• 10:37Neil deGrasse Tyson?

  Okay, got it.

• 10:38Speaker 01

  That's right. Um.

• 10:40Neil deGrasse Tyson?

  Keeping with the maternity theme of the show.

• 10:43Speaker 01

  I just had a baby a month and a half ago, so I got a baby.

• 10:46Neil deGrasse Tyson?

  Right, how many kids you have? How many kids?

• 10:48Speaker 01

  Three, that was my third.

• 10:50Chuck Nice?

  Ah, three little lavas, that's so lovely.

• 10:54Neil deGrasse Tyson?

  And they're spilling all over the house.

• 10:55Speaker 01

  Everywhere, everywhere.

• 10:59Speaker 01

  Everywhere.

• 11:00Chuck Nice?

  Nice.

• 11:01Speaker 01

  Yeah, so we learned that the moon has had an incredible geologic history. It had been processed, it had been melted and minerals, different types of minerals formed. And it made us think about, okay, so it didn't form the way we thought it did. So how did it form?

• 11:22Neil deGrasse Tyson?

  Okay, so that's so, so, so your biggest surprise was not a question that it answered. It was a question that it left you not knowing the answer to.

• 11:34Speaker 01

  That's right, and I think that's the most exciting thing.

• 11:36Neil deGrasse Tyson?

  Yes, okay.

• 11:37Speaker 01

  When you have more questions, when things don't lead to the answer, you have more, more things to explore.

• 11:42Neil deGrasse Tyson?

  All right, so what other questions you got, Chuck?

• 11:45Chuck Nice?

  Uh, here's Robert Weaver, also from Patreon. And Robert says, "My daughters Lila and Peyton would like to know how come the moon has so many craters and the Earth doesn't have any?" Um, and I'm gonna say, Robert, you tell Lila and Peyton to go look it up. We're not here to do their homework.

• 12:10Neil deGrasse Tyson?

  Go Google it, next question.

• 12:11Chuck Nice?

  That's a question, all right.

• 12:13Speaker 01

  I love that question. So actually, the Earth does have craters. So we have about, I think it's about 150 recognized craters on the surface of the Earth. But because, like I said, the Earth is very geologically active. We have plate tectonics that's causing the plates to subduct underneath each other. You essentially erase the history of what has happened in the past on Earth. And the other thing we have, we have an atmosphere. So certain rocks, if they're small enough, they just burn up in the atmosphere. They never enter, uh, they never hit the ground. Whereas on the moon, anything that hits it, if it's a large enough size, it's gonna create a crater.

• 12:54Speaker 01

  Uh, and then we also have wind which erodes any evidence of past craters. We have water that also erases evidence. And even life, little critters making their homes underground collapse.

• 13:06Speaker 01

  Crater features here on Earth, so that's why we don't see them. We've had them and we have them. Um, there's actually a beautiful crater in Arizona called Meteor Crater that formed about fifty thousand years ago and it it's one of the best. I think it might be one of the best preserved crater on Earth. And you can really, you can see it and it's cool. Yeah.

• 13:24Neil deGrasse Tyson?

  You preserve not because there was a preservation society, but because it was in the desert, right?

• 13:29Speaker 01

  That's right.

• 13:29Neil deGrasse Tyson?

  There's not much more rain.

• 13:31Speaker 01

  Exactly.

• 13:32Neil deGrasse Tyson?

  And it's a geologically dead area, right?

• 13:35Speaker 01

  Exactly.

• 13:35Neil deGrasse Tyson?

  Yeah, okay.

• 13:36Chuck Nice?

  Oh, that's super cool. So, so the Earth is basically a contaminated crime scene. You can never, you never know what's going on.

• 13:45Speaker 01

  It's constantly being bleached, being cleaned over.

• 13:51Chuck Nice?

  Okay, you just made me, you just made me nervous, Raquel. I'm sorry. I'm serious. I'm like, wait a minute. You know, you know a lot about cleaning up a crime scene.

• 14:02Speaker 01

  I used to be in the military and I was.

• 14:04Neil deGrasse Tyson?

  She went straight to that.

• 14:05Speaker 01

  I went, I worked in a medical laboratory, so I'm like, I, I know about cleaning, cleaning things.

• 14:10Chuck Nice?

  Okay, all right.

• 14:11Neil deGrasse Tyson?

  Cleaning the evidence, yes.

• 14:14Chuck Nice?

  That's very cool.

• 14:15Neil deGrasse Tyson?

  But what you're meaning to, just to summarize, I think, is if we didn't have these cleansing, these evidence removing processes, we would look just like the moon.

• 14:26Speaker 01

  That's right, just like it. Everything that, this is what I meant by the moon being a witness blade is everything that is.

• 14:33Neil deGrasse Tyson?

  Cause we're in the same part of the solar system together.

• 14:34Speaker 01

  Exactly, exactly, exactly, yeah.

• 14:37Neil deGrasse Tyson?

  All right. All right, Chuck, give me some more.

• 14:40Chuck Nice?

  All right, um, let's see here. This is, hmm, hmm, uh, Canadian. Nope, Canadian, very funny, the way they spelled it. This is Canadian from Patreon. Hello, Neil.

• 14:56Neil deGrasse Tyson?

  Chuck, stop blaming how people spell things on the fact that you can't pronounce their names.

• 15:00Chuck Nice?

  What else am I gonna blame it on?

• 15:05Neil deGrasse Tyson?

  Oh, this person is messing with me.

• 15:09Chuck Nice?

  Please, as much as I butcher names, I'm telling you, I gotta find a way to, you know.

• 15:16Chuck Nice?

  I gotta have some excuse. Alright, hello Neo, Chuck, and Raquel. If future moon missions end up drilling into the surface and extracting a core sample like we do on Earth, what do you think we might find? How far down do you believe the rock layer extends before we start hitting cheese? Okay.

• 15:40Neil deGrasse Tyson?

  Or oil, yeah.

• 15:41Chuck Nice?

  Right, exactly.

• 15:43Neil deGrasse Tyson?

  They both have value.

• 15:43Chuck Nice?

  Yes, right, right, right, right.

• 15:46Speaker 01

  Oh, man, as much as I love cheese and wish I could eat some moon cheese, I think we'd have to go pretty far down to not find it.

• 15:57Chuck Nice?

  Nice job. I like the misdirection. I like the misdirection. Yeah, what makes you think the surface isn't cheese?

• 16:05Speaker 01

  But it turns out there are layers.

• 16:07Chuck Nice?

  Yeah, I was gonna say, what will we find if we actually pull the core out?

• 16:11Speaker 01

  Yeah, well, it depends on how far you go, but the moon is a differentiated body. So like I said before, it's melted and it's been separated. The heavy stuff sank to the bottom and the light stuff's at the top. So what you have, you have a core in the center, you have your mantle, and then you have your crust, like here on Earth.

• 16:30Neil deGrasse Tyson?

  But just to be clear, when people, you know, we think of rocks as heavy things because they go to the bottom of a pool. But when you think of rocks, you think of light things. Because metal things are heavier than rocks are.

• 16:43Speaker 01

  That's right.

• 16:44Neil deGrasse Tyson?

  Or denser, right, right.

• 16:46Speaker 01

  They're more dense, so they...

• 16:47Neil deGrasse Tyson?

  Yeah, you say, oh, the light things float to the top. They're rocks. What the boulders? What the hell are you talking about?

• 16:52Speaker 01

  Yeah, right. Yeah, no, that's, I have a very different perspective of...

• 16:56Neil deGrasse Tyson?

  Because you're a geologist. You're from another species of person. Okay.

• 17:00Speaker 01

  But on top of the crust, we have what's called the regolith. So because the moon has been bombarded by, you know, billions of years of rocks hitting its surface, it's broken up the rocks that were there before. And so there's this powder of dust on the surface that I think it's between five and 10 meters on top.

• 17:21Neil deGrasse Tyson?

  So it's not a matter of breaking apart the rocks, it's like completely pulverized?

• 17:27Speaker 01

  Pulverizing them, yes.

• 17:28Neil deGrasse Tyson?

  Yes, yes, turns it into powder.

• 17:30Speaker 01

  That's right.

• 17:31Neil deGrasse Tyson?

  Is this the same stuff they tried to get, they couldn't get off the spacesuits?

• 17:34Speaker 01

  That's right, so it ends up being very sharp because there's no water or anything to round out the corners. The, these fragments are so sharp that when they stick to you, it's like impossible to get them off. And we, we actually, we have samples in our lab, there's people in our lab that study optical properties of the regolith. And the samples that we got were removed from the astronauts' spacesuits. So they brushed, they were trying to save everything they can because it's such precious material.

• 18:04Neil deGrasse Tyson?

  It cost a hundred zillion dollars to get to the moon. You don't want to leave anything in the trash can.

• 18:08Speaker 01

  So when they brought, you know, the astronauts came back, they got their suits and brushed off their dust and we actually used that for scientific research. And you can find little fibers in there, it's funny.

• 18:20Neil deGrasse Tyson?

  And it's not mixed with their dandruff, right? Oh man, that'd be so cool. That'd be an interesting thing. It's like, oh, you don't use head and shoulders? We're gonna take a quick break. When we come back, more StarTalk Cosmic Queries with Raquel Nuno when we return.

• 18:53Neil deGrasse Tyson?

  We're back, StarTalk Cosmic Queries. This episode on the moon. The moon is a geological object, not just a pretty thing in the nighttime sky. Chuck? But we don't mind that, we don't mind that it's a pretty thing in the nighttime sky. That's right, that works, that works. And we have Raquel Nuno, who's a doctoral candidate at UCLA, studying the moon, coming to it as a geologist. And that's a whole other species of scientist, far as I'm concerned, because you all see the world very differently from the astrophysicist. You know, you look at the moon, you see rocks on the moon. I look at the moon, I just see a beautiful orb in the sky. That's all, that's where it ends for me. And then I go to Mars to look for life, see? So Chuck, you got more questions? Sure, sure thing. This is from Kevin.

• 19:42Chuck Nice?

  Kalakikamaka.

• 19:44Neil deGrasse Tyson?

  You just made that up.

• 19:46Chuck Nice?

  Nailed it!

• 19:49Chuck Nice?

  I don't know what it is, man. He said, I mean, it says, it says Kevin Kalakikamaka, I think. But, uh, and, and if it is Kal- uh, Kevin Kalakikamaka, then I say, uh, aloha. Um, uh, he says, um, uh, what is it when the moon hits your eye like a big pizza pie? No, I'm joking. He does not say that. He did not say that. Okay. Here's what he says. Can the, can the moon have a moon? And can that moon have a moon as well? I think this is a question more for Neil, but maybe you know too, Raquel. Do, are there any?

• 20:33Chuck Nice?

  Cause this is really kind of a really interesting question. Are there any instances that we find in the cosmos where a moon also has its own satellite?

• 20:44Speaker 01

  So we, I don't think we've found one yet, at least definitely not in our solar system. But it is theoretically possible to have a moon of a moon. And there's a, a paper that came out, I think they called it a submoon or moon moon. Depends on, I think there was a thing on Twitter where people on Twitter were like, no, we want moon moon. Because it hasn't been named officially yet.

• 21:05Chuck Nice?

  Right.

• 21:06Speaker 01

  Uh, so, um, but yeah, so theoretically you can have a moon of a moon. But I think what the problem is, is that, um, you have to have the right conditions. Because if, for example, I think if it's, the moon is too close to the parent body, like the planet, you can just disableize its orbit and it will either spiral out of, of orbit or into the planet. So, um, Neil, do, do you have any more insights about that?

• 21:31Neil deGrasse Tyson?

  Yeah, yeah, I agree entirely. Yeah, it's a matter of, uh, I mean, just, just think it through. So let's say our moon had a moon, right? And so it's going around our moon. Think as it comes to this side. Earth's gravity on it will be stronger, much stronger than it is on the other side. So here's this satellite that's getting tugged asymmetrically as it's trying to orbit the moon. And this creates a conditions for very unstable orbits. When you have an unstable orbit, your future is doomed. Either, as Raquel said, to fall into the earth or to spiral off.

• 22:04Chuck Nice?

  Spiral off, right.

• 22:05Neil deGrasse Tyson?

  So you need, in order to have one of these three body systems, what you would need is a very big separation between the planet and the moon, so that an object can go around that moon and not have the difference in gravity be so great. That's what the moon and earth is relative to the sun.

• 22:25Chuck Nice?

  Right.

• 22:26Neil deGrasse Tyson?

  Okay, if earth is a moon of the sun, then the moon is a moon moon of the sun. Okay, but that's okay, because we're really far away from the sun. So you can do the math on the fabric of the stable orbits, and you can see where you can put objects where they can stay, and where you can put objects where they're unstable, so.

• 22:47Chuck Nice?

  See, and now I am really, not that I could do the math, because I couldn't, but now I'm just thinking, how cool would it be to create a solar system mathematically, where you could actually have a planet, a planet, the moon, its moon, and they all are in orbit, so that the gravity pulls just at the right time to keep everything in balance, like those plate spinners on the, you know, like.

• 23:21Neil deGrasse Tyson?

  Raquel, Chuck has always wanted to be god. You see, that's what he's trying to do. Yeah, these are ambitions that he's had.

• 23:28Chuck Nice?

  Okay, alright.

• 23:30Neil deGrasse Tyson?

  He's got a long way to go, I think.

• 23:32Speaker 01

  He's on the right path, though. I like these ideas.

• 23:34Neil deGrasse Tyson?

  But it is fun, Chuck, there are these orbit programs.

• 23:37Chuck Nice?

  Yeah.

• 23:38Neil deGrasse Tyson?

  Where you try to create a solar system, and you might be surprised how hard it is.

• 23:43Chuck Nice?

  Yeah.

• 23:43Neil deGrasse Tyson?

  Because you, "I want to put a planet here at this speed." Nope, that's going to fall into the sun. So there's only a speed that works at a distance in whatever is the shape of the orbits that it has. So, in fact, a solar system, correct me if I'm wrong, Raquel. Recent models suggest that we might have started out with as many as 30 planets.

• 24:01Speaker 01

  Right.

• 24:01Neil deGrasse Tyson?

  In the formation scenario, most of which have spiraled off into interstellar space. Is that about the right number, 30? Is that a fair number to use?

• 24:09Speaker 01

  That rings right and it seems reasonable, but yes, that was

• 24:12Neil deGrasse Tyson?

  Yeah, I think that the takeaway is there's more planets that we don't have than we currently have.

• 24:17Speaker 01

  Right.

• 24:17Neil deGrasse Tyson?

  That have been ejected out.

• 24:19Speaker 01

  Ejected out, yeah.

• 24:20Chuck Nice?

  Wow, okay, alright, that is super cool. Okay, here we go. Um, Morgan Tanji, also from Patreon. If there's no weather or atmosphere on the moon,

• 24:34Chuck Nice?

  where does the ice come from?

• 24:38Neil deGrasse Tyson?

  Ooh, because we learned about ice, there's ice on the moon.

• 24:41Chuck Nice?

  Uh huh, uh huh, uh huh.

• 24:46Neil deGrasse Tyson?

  So you just thought you knew everything, but you don't. There's ice, so there.

• 24:50Speaker 01

  There's still so much to learn.

• 24:53Neil deGrasse Tyson?

  We think there are thunderstorms on the far side, you just can't see them.

• 24:57Chuck Nice?

  That'd be so cool.

• 24:59Neil deGrasse Tyson?

  That would be cool, would be cool. So what's up with the water on the moon?

• 25:02Speaker 01

  Yeah, so there's different sources of water on the moon. They can come from comets and meteorites that bring water to the surface of the moon.

• 25:15Speaker 01

  You also have, what I think is really cool, is the sun. So the sun is spewing this massive amount of charged particles called the solar wind. And protons from the solar wind hit the surface of the moon, so hit oxygen that's on the rocks. Hit the rocks and bond with oxygen, forming water, like hydrated minerals.

• 25:38Neil deGrasse Tyson?

  Wait, the proton is the nucleus of a hydrogen atom?

• 25:41Speaker 01

  Yes, that's right.

• 25:42Neil deGrasse Tyson?

  So hydrogen.

• 25:43Speaker 01

  Hydrogen.

• 25:44Neil deGrasse Tyson?

  Yes.

• 25:44Speaker 01

  Combining with the oxygen in the rocks, forming hydrated minerals, forming water at the surface of the moon. And there's actually

• 25:54Chuck Nice?

  So wait a minute, is this like water out of thin space?

• 25:57Speaker 01

  Right, yes.

• 25:58Chuck Nice?

  What?

• 26:00Neil deGrasse Tyson?

  The water just got conjured out of particles.

• 26:04Chuck Nice?

  Right? It's like, wow, you're just looking for the moon to have a wand, just like, it's priyama, right? Water, that's crazy.

• 26:12Speaker 01

  Yeah, and there's actually one other place that we get water from, and that's actually from the interior of the moon. And we didn't know this until recently. They did, there's these They call them glass beads. They're just volcanic glasses that from the samples collected from the Apollo, by the Apollo astronauts. And when you slice them open and look inside, you actually find trapped water molecules inside those glass beads. So that tells you that there is water, at least in the past, when the moon was geologically active, there was water trapped within the mantle.

• 26:48Neil deGrasse Tyson?

  Okay, but it gets very hot during the day. Why doesn't all that just evaporate?

• 26:52Speaker 01

  Oh, that's a good question. So...

• 26:54Neil deGrasse Tyson?

  See Chuck, I asked a good question.

• 26:55Chuck Nice?

  You did. You know what?

• 26:57Neil deGrasse Tyson?

  I got that compliment.

• 26:58Chuck Nice?

  I didn't want to break up the flow, but I was about to say, it better be a good question. Like, could you imagine if Neil asked a question and you were like, what a crap-ass question that was? Oh my god!

• 27:11Speaker 01

  I'm glad I didn't do that.

• 27:12Chuck Nice?

  Wait, did Neil deGrasse Tyson just ask me that?

• 27:14Neil deGrasse Tyson?

  The dumbass.

• 27:18Chuck Nice?

  What? Alright.

• 27:23Speaker 01

  Yes, so, that question. So, what ends up happening is there's these places at the poles, these craters at the poles of the moon, so at the top and at the bottom, that haven't seen sunlight. They're so deep, and because of the way that the moon rotates, they haven't seen sunlight for billions of years. So, it's very cold. It actually turns out to be one of the coldest places in the solar system, actually even colder than the surface of Pluto. And so if water ends up there, it gets trapped, essentially forever, for billions, millions of years. And that's where the ice is. That's where we think that the ice is, is trapped inside these, we call them permanently shattered regions, because they're so cold, essentially

• 28:08Speaker 01

  nothing can escape it.

• 28:10Neil deGrasse Tyson?

  Raquel, you can say it. The water is where the sun don't shine.

• 28:13Speaker 01

  That's exactly right.

• 28:16Neil deGrasse Tyson?

  There's an expression for that, I think. So, I guess if you're on the poles, the sun never gets very high in the sky.

• 28:22Speaker 01

  That's right.

• 28:23Neil deGrasse Tyson?

  And so you can have a crater lip... That permanently shadows because the shadows are very long by the low sun.

• 28:29Speaker 01

  That's right.

• 28:30Neil deGrasse Tyson?

  And that those pockets are where you're talking about.

• 28:31Speaker 01

  That's right.

• 28:32Neil deGrasse Tyson?

  So if we're going to have colonies on the moon and want to use in situ resources, we got to have some access to these to these craters at the poles.

• 28:39Speaker 01

  That's right.

• 28:40Neil deGrasse Tyson?

  In order to get the water.

• 28:40Speaker 01

  And that's a lot of a lot of mission concept designs have been to go to these crater rims. So you can you still have access to sunlight to power your equipment. And also now you have these permanently shadow regions where you can go and collect the ice that we think is there.

• 28:57Neil deGrasse Tyson?

  OK, the moon is sounding a little more interesting.

• 28:59Chuck Nice?

  Yeah, I gotta tell you. So now let's I just have a question. So when you the water that we're talking about that in the form of ice, whether it's deposited there or it it it just forms. Is it is it is it potable? Is I mean, is it like is it like is it just water? Can we drink it or is it, you know, something else?

• 29:23Speaker 01

  It was so it is water, but it's probably mixed in with the that regolith that moon.

• 29:28Chuck Nice?

  So it's got all that mineral and all the other crap is in there too.

• 29:32Speaker 01

  You might need to bring some some filters with you if you're going to drink.

• 29:36Neil deGrasse Tyson?

  You need some machine to to scoop up the regolith and have some, you know, a spigot at the end, but something's going to have to process it.

• 29:42Speaker 01

  That's right.

• 29:43Neil deGrasse Tyson?

  Because because a lot of these is it true? A lot of these are just sort of isolated or just a few water molecules?

• 29:50Speaker 01

  Yeah, at the surface, yes, yes. It's it's pretty much just like a coating on these minerals that you have some coating of of water. So you need to go to these permanently shadow regions where we think there's large amounts of of water ice, but we don't know how much. And and that's actually a really exciting field of research is is sending more spacecraft or people try to figure out what what is happening in these regions.

• 30:16Neil deGrasse Tyson?

  So if I went back to the moon, I'd want to go to near one of those coal traps. I would. And start digging around. Yeah. I'd bring my ice skates, too, maybe. That's right. Play some moon hockey. Moon hockey, whoa.

• 30:27Chuck Nice?

  I like it. I like it.

• 30:29Neil deGrasse Tyson?

  All right, Chuck, what else you got?

• 30:30Chuck Nice?

  All right, this is Evan Wells from Patreon who says this. "Dr. Tyson and Dr. Soon-to-be Nuno. I've been waiting for this topic for a very long time, as I'm a big fan of the moon, as well as planetary geology. Do you two personally believe in Theia? Is that correct? Am I saying it right? Thia? Theia? T-H-E-I-A? The most logical theory of the moon's origin. Are there any other examples that you can recall of the moons that are exceptionally close to their planet, such as our moon? Looking at different other moons in the solar system. Thanks and so much respect from the Space Coast."

• 31:15Neil deGrasse Tyson?

  Oh, down in Florida.

• 31:16Chuck Nice?

  Yes.

• 31:17Neil deGrasse Tyson?

  Very excellent. That's a really great question, which we don't have time to answer.

• 31:21Chuck Nice?

  Oh, no.

• 31:21Neil deGrasse Tyson?

  And come back from this break.

• 31:23Chuck Nice?

  Okay.

• 31:23Neil deGrasse Tyson?

  See what I did there? I teased it. That's what the pros do, that.

• 31:28Neil deGrasse Tyson?

  We're gonna be right back. StarTalk Cosmic Priors, the moon.

• 31:41Chuck Nice?

  Hey, we'd like to give a Patreon shout-out to the following Patreon patrons, David Frederick and Jennifer Eichen. Guys, thank you so much for all that you do to make StarTalk a success. And if you would like your very own Patreon shout-out, go to patreon.com/startalkradio and support us.

• 32:09Neil deGrasse Tyson?

  We're back with Chuck Nice, my co-host Chuck.

• 32:11Chuck Nice?

  Yes, yes.

• 32:13Neil deGrasse Tyson?

  And our special guest today, Raquel Nuno. And Nuno, I feel, I have Hispanic background and so to say Nuno feels wrong.

• 32:22Chuck Nice?

  I know. I hear you struggling with it too. It's so funny.

• 32:25Neil deGrasse Tyson?

  That's the Nuno. So you have a Portuguese roots.

• 32:29Speaker 01

  I do, yeah. That's born, raised. My whole family's been there for...

• 32:32Neil deGrasse Tyson?

  So they don't have an "ñ" in Portugal?

• 32:35Speaker 01

  No, we don't. So if you want to make that sound, it would be an "N" and then an "H" afterwards. That's how we make the "ñ" sound.

• 32:41Neil deGrasse Tyson?

  "ñ".

• 32:43Speaker 01

  Yeah, but my name is just Nuno, just an "N".

• 32:46Neil deGrasse Tyson?

  Okay. All right, where we left off Chuck, there was a question about Thea.

• 32:50Chuck Nice?

  Yeah.

• 32:51Neil deGrasse Tyson?

  Is that correct?

• 32:51Chuck Nice?

  So Evan Wells wants to know this. Do you two personally believe in Thea? And the other thing is, are there moons in the solar system that are like our moon? So the whole idea of Thea, can you let me in on that please?

• 33:08Speaker 01

  Sure. So the idea was that a Mars-sized object, which we're calling Thea, impacted an early Earth. And it was such a massive impact that sprayed all this material out into space and that it condensed out and formed our moon. So that's the idea. So Mars-sized object called Thea hit the Earth and formed the moon.

• 33:34Neil deGrasse Tyson?

  Just to be clear, Thea is gone.

• 33:36Speaker 01

  Yes.

• 33:37Neil deGrasse Tyson?

  Yes, and so some became Earth and the rest became the moon and some scattered wherever else.

• 33:43Speaker 01

  That's right, that's right.

• 33:44Chuck Nice?

  So now, wait a minute. For this to happen, that thing would have to be super, super hot. Like, you know what I mean?

• 33:52Neil deGrasse Tyson?

  So Chuck, you'll get hot just from the collision?

• 33:53Speaker 01

  Yeah, it gets hot.

• 33:54Chuck Nice?

  Oh, so the collision that's does the...

• 33:56Neil deGrasse Tyson?

  Oh yeah, you get that for free.

• 33:58Chuck Nice?

  Oh, that's super cool.

• 34:00Neil deGrasse Tyson?

  You don't have to order that.

• 34:01Chuck Nice?

  Okay, great. Oh, okay, okay.

• 34:04Speaker 01

  And that's actually, that's what would cause all that impact. So then when the moon formed and all these pieces came together, it heated up the surface of the moon and that's how we got that magma ocean. It completely melted. So you, yeah, you get energy just from things, you get heat from things hitting each other.

• 34:23Neil deGrasse Tyson?

  Wow! Alright. So what's the status of that hypothesis? Is it embraced?

• 34:27Speaker 01

  So, yeah, I mean, it's the best we got.

• 34:29Neil deGrasse Tyson?

  I read it, I read it, it was like, yeah, I'll go with that. It's fun to talk about. And on multiple occasions, people said, "If I could go anywhere in the universe, where would I go?" And I said, "Does that include time?" And they said, "Sure." I said, "I want to go back and watch Thea hit the Earth."

• 34:44Speaker 01

  That'd be amazing.

• 34:44Neil deGrasse Tyson?

  And see the moon get formed, yeah. That's cool, man. So you're saying it's got good support by your people?

• 34:50Speaker 01

  It definitely has good support. So we know that early in the solar system, giant impacts like this were very common. So it makes sense that this would have happened to us. And they would produce moons and disks. And there's other pieces of evidence in geological records. So the moon actually lacks iron in bulk. So what we think happened is when Thea hit the Earth, the its core, the core of Thea, kind of sank into our Earth. And what you ended up having is the mantle stuff, so the stuff without the iron, to form the moon. So then there's the evidence for against it is

• 35:32Speaker 01

  the fact that the moon rocks are so similar to the ones here on Earth. You would expect that you would see some evidence of Thea somewhere. And we don't. So we do not have any evidence of Thea material here on Earth or on the moon. So we need an explanation as to why that is and how that happens.

• 35:55Neil deGrasse Tyson?

  So if you found an asteroid stream around the Sun, and you looked at its ingredients, and they matched some combination of Earth and the moon, that could be the remains of Thea.

• 36:07Speaker 01

  That's right.

• 36:09Neil deGrasse Tyson?

  Orbiting, still orbiting the Sun.

• 36:10Speaker 01

  That is right. But how do you form two objects that are essentially identical? So that would mean that the moon, that Thea and the Earth were very similar to begin with.

• 36:23Neil deGrasse Tyson?

  To begin with, okay.

• 36:24Speaker 01

  And we have a very hard time with models making that happen. It's very hard. Because when we look at other objects, other planets, asteroids, everything is really different. You can find the fingerprint for each of these bodies and...

• 36:41Speaker 01

  We really can't with the Earth and the Moon.

• 36:44Neil deGrasse Tyson?

  So, what other moon in the solar system comes closest to matching our own?

• 36:48Speaker 01

  Well, I guess it depends on what you're trying, what do you mean by closest? So, if you're talking about size, so the Moon is very big compared to the Earth. Because when you look at other moons in the solar system, the planets are huge compared to the size of their moons.

• 37:04Neil deGrasse Tyson?

  But it's not only big compared to Earth, it's big compared to anything.

• 37:08Speaker 01

  Anything, that's right.

• 37:09Neil deGrasse Tyson?

  All the other, if you line up all the moons, our Moon is like in the top side of that.

• 37:13Speaker 01

  It's huge, absolutely, yeah, it's very, it's weird.

• 37:16Chuck Nice?

  Way to go, Earth, yeah.

• 37:18Neil deGrasse Tyson?

  Weirdly huge.

• 37:19Speaker 01

  But Pluto, I know it's not a planet, has a moon that...

• 37:24Neil deGrasse Tyson?

  Hold me back!

• 37:28Speaker 01

  But it has a moon that is very large compared to Pluto itself. So in that sense, it is similar to our system, our Earth-Moon system is similar to the Pluto-Sharon system because of the size, the size ratios between the planet and the Moon, yeah.

• 37:46Chuck Nice?

  Alright.

• 37:47Neil deGrasse Tyson?

  Alright Chuck, keep going.

• 37:49Chuck Nice?

  Here we go, this is Will from Twitter, he says, "Do you think there is bacteria still alive in the Apollo missions, oh god, leavings, I will say, the bags that they had to leave? If there is none that have survived, what would that mean for future deep space travel?"

• 38:15Speaker 01

  So I'm guessing, oh, I think I know, okay, I think I know the question, okay?

• 38:19Chuck Nice?

  Yes, yes, yes.

• 38:21Speaker 01

  So, they did do that.

• 38:24Neil deGrasse Tyson?

  You mean these poop bags?

• 38:26Chuck Nice?

  Yes, the poop bags.

• 38:27Speaker 01

  Yes.

• 38:28Chuck Nice?

  See, because you can say that, Neil, when I say poop bags, people go Chuck.

• 38:34Neil deGrasse Tyson?

  Okay, so here we go. I'll restate it. These poop bags.

• 38:42Neil deGrasse Tyson?

  Describe for me the bacterial composition of these poop bags.

• 38:46Chuck Nice?

  Thank you, Neil.

• 38:47Speaker 01

  So the question was, do I think there's any bacteria still alive?

• 38:51Chuck Nice?

  Yeah, would there be any bacteria still?

• 38:54Neil deGrasse Tyson?

  But wait, just to be clear, they left it on the surface of the moon?

• 38:57Speaker 01

  They did.

• 38:58Neil deGrasse Tyson?

  Wait, you have to carry your poop out of our national parks or something?

• 39:04Neil deGrasse Tyson?

  There's some places that are so preserved, you can't, you can barely pee on a tree and scraping it off and taking it out of the park with you, and we can leave poop on the moon?

• 39:13Speaker 01

  I know.

• 39:13Chuck Nice?

  Yeah, these astronauts are like the neighbors that I have, because I live next door to a doggone dog park, okay? They're worse than my neighbors!

• 39:23Neil deGrasse Tyson?

  Rekha, I didn't know that.

• 39:24Speaker 01

  Yeah, yeah, yeah, so if you had a choice, would you want to bring poop back to Earth or rocks back to the Earth?

• 39:31Neil deGrasse Tyson?

  That is true, it's a trade-off, isn't it?

• 39:32Speaker 01

  So, you want to bring...

• 39:34Neil deGrasse Tyson?

  I'm bringing the rocks.

• 39:35Speaker 01

  You're bringing the rocks, so weight is a very important thing when it comes to space travel and space exploration, so you're gonna try to maximize the quality of the weight that you're actually transporting.

• 39:49Speaker 01

  I don't think that there's bacteria alive, so I know that the poop bags had dermalidol in them to actually kill bacteria, so the bags themselves, I think they had to tear these pouches and pour it into the, and mix the stuff with...

• 40:08Neil deGrasse Tyson?

  TMI, TMI.

• 40:12Speaker 01

  And there's, but there's other reasons why I don't think it's alive, nothing's alive in there. Irradiation is a really big challenge in space, so it's probably been completely irradiated throughout all these years.

• 40:25Neil deGrasse Tyson?

  So this is irradiation because it has no atmosphere to protect it?

• 40:28Speaker 01

  That's right.

• 40:28Neil deGrasse Tyson?

  Anything coming hits the surface?

• 40:30Speaker 01

  Yeah, and also the heat, so the surface of the moon can get as hot as, I think, 260 degrees Fahrenheit, so you essentially have probably cooked everything that was in the bag.

• 40:41Neil deGrasse Tyson?

  Baked poop.

• 40:44Chuck Nice?

  You know, I'm getting the-

• 40:45Neil deGrasse Tyson?

  A specialty in some parts.

• 40:47Chuck Nice?

  Getting the feeling that after this conversation, there'll be several young people who are like, "Yeah, I don't think I'm gonna be an astronaut."

• 40:55Speaker 01

  Oh, that's sad. No, no, no, we need astronauts.

• 40:58Chuck Nice?

  Yeah. All right. Um, let's see here. This is Whoopsie Doodle.

• 41:06Neil deGrasse Tyson?

  You could pronounce that one, Chuck.

• 41:07Chuck Nice?

  Yes, you're damn right. Finally, somebody likes me. Whoopsie Doodle says, "Dr. Tyson and Raquel, and hi Chuck. My question is, can you explain what is the dark side of the moon?"

• 41:26Speaker 01

  So, there is no dark side of the moon.

• 41:29Neil deGrasse Tyson?

  There, next question.

• 41:33Neil deGrasse Tyson?

  Raquel said it, we're done.

• 41:36Chuck Nice?

  That was easy.

• 41:36Speaker 01

  But a lot of people don't know that. A lot. So, we don't have a dark side. It's only a side that we never see, because the moon is tidally locked to the earth. So, but it's not dark. It gets sunlight.

• 41:50Neil deGrasse Tyson?

  And so Gary Larson did it right, with the name of his column was "The Far Side."

• 41:54Speaker 01

  That's right.

• 41:55Neil deGrasse Tyson?

  And Pink Floyd got it wrong, where the name of their album was "The Dark Side."

• 41:59Speaker 01

  That's right.

• 41:59Chuck Nice?

  Got you.

• 42:00Neil deGrasse Tyson?

  This is a measure of science literacy.

• 42:02Speaker 01

  Yeah, we call it the far side. That's what we called it, what a lot of people know as the dark side.

• 42:08Chuck Nice?

  Yeah, it's dark to us.

• 42:15Chuck Nice?

  All right. So, Manuel Delgado, and it's actually Delghetto. Wow, Delaghetto, there it is. Manuel Delaghetto from Instagram says, "In the film Time Traveler, the moon breaks apart due to mining."

• 42:36Chuck Nice?

  What would happen to the Earth if the moon broke apart? By the way, that's, that's, I think, the Umbrella Academy. That's, that's the destruction of the Earth, too. The piece of the moon breaks off and destroys the Earth. But what, what would we be?

• 42:53Neil deGrasse Tyson?

  It's also true in the movie Melancholia. The, the moon approaches Earth and then they collide. And everyone dies.

• 43:01Speaker 01

  My, my favorite book called Seven Eves, that happens in the first page as well.

• 43:06Chuck Nice?

  In the first page?

• 43:07Speaker 01

  The first page.

• 43:08Chuck Nice?

  That's what I was gonna say.

• 43:09Speaker 01

  The moon breaks up.

• 43:11Chuck Nice?

  And it picks up from there.

• 43:15Neil deGrasse Tyson?

  And they live happily ever after.

• 43:16Chuck Nice?

  Exactly. Alright, so but what would we, what are we without the moon?

• 43:21Speaker 01

  It would be a very bad time on Earth if, if the moon broke up. So the energy between the pieces breaking up and hitting each other would destabilize their orbits and they would end up crashing into the Earth. And that would be bad, very, very bad, as we know happened to the dinosaurs.

• 43:42Neil deGrasse Tyson?

  With much smaller pieces than what would be coming from Earth.

• 43:45Speaker 01

  Yeah, so it would, the Earth, we wouldn't survive. Life might not even survive if that were to happen.

• 43:53Speaker 01

  But if you don't even take that into account, so let's, we don't worry about pieces falling into, into Earth. The, the moon provides the Earth with a very stable orbit. So we don't tilt, the Earth doesn't tilt very much because it has the, the moon there to stabilize its orbit. So that's why we have very mild seasons. So if we didn't have the moon there, our seasons would, we would have years, thousands of years of ice ages and then, and life would not survive. The same thing actually happens on, on, in Mars because Mars has small moons. They don't stabilize their orbits. So Mars is always tilting over periods of millions of years. And yeah, so bad, bad thing.

• 44:34Speaker 01

  But, but, but to be clear, this would not happen if you're just with normal mining techniques. You don't have enough energy to actually break up the moon. So we don't have to worry about that.

• 44:43Neil deGrasse Tyson?

  Unless they find Roker for cheese and they pull it all out. That's half the mass of the moon. That'll totally, that'll totally mess up the moon. We, we confessed earlier in the show, you have to dig very deep to not find cheese. I think you said that in the beginning of this program, didn't you?

• 44:59Speaker 01

  What do you think Neil, if the moon broke apart? Like, that's terrible, right? For the Earth?

• 45:05Neil deGrasse Tyson?

  Yeah, but I think that our axis would go unstable on a period of time longer than civilization. I mean, tens of thousands of years, not just a few thousand. So, I think astronomers would love it, because the moon completely messes up our night sky. We can't see anything when the full moon is out. So I would love it for the time until we all died. It would be great.

• 45:25Chuck Nice?

  That's so funny. Alright, that's funny. Yeah, well...

• 45:31Neil deGrasse Tyson?

  Chuck, what do you have next?

• 45:32Chuck Nice?

  This is Deci, uh, Deci from Twitter says, "What color is the moon really? Is it, is it all really gray? Are there features in different colors? And, and why? Why?" Okay, so, and then he says, "Chuck, you get 10 cosmic points if you say my name correctly." Well, guess what? Keep your points. Because you know damn well, uh, let's see, uh... Dicheme? Okay, that's all I can say, maybe. That, that might be your name. Okay? Okay.

• 46:14Neil deGrasse Tyson?

  So what do you have, Raquel?

• 46:16Speaker 01

  Well, what's really interesting is that, how many people think that the moon is white? Or this very light gray color? You know, when I do outreach events, people, and I bring moon dust with me, people are like, "Whoa, it's so dark, I thought it was white." Uh, and it's not, it's actually a very dark thing in the sky. When you look up at the night sky, you see these different regions. So you have the dark and the light regions. And in the dark regions, those are ancient volcanic plains. So those rocks are like black lava rocks that you see in Hawaii or in Iceland. They're, they're almost as dark as a newly paved road. So it's, it's very, very dark. Those rocks are very dark. Um, and then the lighter region of the moon, um, those are the highlands.

• 47:01Speaker 01

  So those are made up of certain minerals that are lighter, but it's still a, a dark gray color.

• 47:08Neil deGrasse Tyson?

  So the fact that the moon is so bright just means the sun is really bright on them.

• 47:11Speaker 01

  That's right. That's the only reason. And the other reason is a relative thing. When it's in our night sky, we look at it compared to a dark background. So it looks even brighter to us.

• 47:22Chuck Nice?

  So what's around it is darker and that makes it look brighter?

• 47:27Speaker 01

  Yes.

• 47:28Chuck Nice?

  That is so cool. So now I'm gonna use the saying, "Black as the moon."

• 47:33Neil deGrasse Tyson?

  Black as the moon.

• 47:35Chuck Nice?

  Black as the moon!

• 47:37Neil deGrasse Tyson?

  Alright.

• 47:38Chuck Nice?

  I like it. Okay. Alright, here we go.

• 47:44Chuck Nice?

  This is Pratik Kotari. Pratik wants to know this. What would it take to make the moon habitable? Is it possible for a colony in the near future?

• 48:01Speaker 01

  Yes, you can have colonies on the surface, but you have to mitigate all kinds of issues like the heat and the radiation. But there's actually lava tubes on the moon that you can go underground with colonies, which is really exciting. But you cannot terraform, so you cannot change the moon to give it an atmosphere, to have running water, because there's just not enough gravity to hold an atmosphere on the moon.

• 48:32Neil deGrasse Tyson?

  Yeah, I don't think people think actively about that. You know, we take it for granted that there's air here available for us to breathe without thinking that the gravity of Earth is keeping the atmosphere on its surface.

• 48:43Speaker 01

  That's right.

• 48:44Neil deGrasse Tyson?

  And so on the moon, the molecules will just escape?

• 48:46Speaker 01

  Absolutely. So you can have maybe a very short time where you might have an atmosphere, but the solar wind will just blow it out of the way. Just blow it out and the gravity won't hold it in place.

• 48:58Neil deGrasse Tyson?

  So what you're saying, apart from the dozen things that will kill you, you can easily just have a colony on the moon?

• 49:03Chuck Nice?

  Yeah.

• 49:04Neil deGrasse Tyson?

  Not a problem.

• 49:07Neil deGrasse Tyson?

  Ignoring those other complications, fine. Right. All right. We gotta call it quits there. And Raquel, thank you for being on the show.

• 49:16Speaker 01

  Thank you for having me. I love talking about the moon, so.

• 49:18Neil deGrasse Tyson?

  Oh, yes, I guess so. That's why we picked you out of the... That's why we did this. So Chuck, always good to have you. Always a pleasure. Tweeting at ChuckNiceComic. Thank you, sir. And Raquel, you do public stuff. Do you have active social media?

• 49:33Speaker 01

  I mostly use Instagram to do my science outreach.

• 49:35Neil deGrasse Tyson?

  And your handle is?

• 49:36Speaker 01

  It's the Space Geologist.

• 49:38Neil deGrasse Tyson?

  But, you know, come on.

• 49:41Speaker 01

  Very on the nose.

• 49:45Neil deGrasse Tyson?

  All right. Great to have you. Good luck.

• 49:48Speaker 01

  Thanks.

• 49:49Neil deGrasse Tyson?

  This has been StarTalk Cosmic Queries, the moon edition. I'm Neil deGrasse Tyson, your personal astrophysicist, as always, bidding you to keep looking up.