Volcanoes on the Moon
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Hey there, Lulu here. We are coming up on the new year. And, you know, we're in our last days of 2024. And this is a time when many people are looking back.

They're making lists of the best books or the best songs or the best movies. Well, I want to consider the best celestial events of 2024. And it is just no question, no contest. The thing that takes the cake was the total solar eclipse.

Back in April, of course, the moon went in front of the sun at just the perfect distance that made it so that a swath of North America was showered in sudden darkness. I skipped work that day. It was a Monday. My wife skipped work, too. We got our kids out of school. We bought a bunch of chips and drove five hours to Indiana so that we could be in the path of totality again.

And in those moments where the moon finally closed over the sun, the temperature suddenly dropped, the birds got all quiet, a guy next to us started playing the pan flute. It was so eerie and so neat. And so today...

What I want to do is play you a show that the Radiolab team made in honor of the eclipse that's all about the moon. The moon, the thing allowing for that eerie darkness. It turns out that shiny, glowy, nice white thing in the sky that you can find at night, well, you might not really know it as well as you think you do.

But hopefully that'll change after you listen to this episode. So here we go. I'm going to play you the episode. Sit back, relax. It kicks off with Radiolab's Molly Webster telling me and Latif Nasser why she was so excited about the eclipse.

So you may have heard we had a big solar eclipse, which I was unabashedly pumped about. I've never I don't I don't get into eclipses so much, but this was my year. And for anyone who is coming into the office every day with the glasses on. So basically an eclipse is like the moon gets between the earth and the sun and

And so then it like blocks the light of the sun and the shadow of the moon is cast upon the earth.

And the shadow is actually about 115 miles wide. And so as the Earth rotates, this shadow of the moon sweeps across the Earth, passing over mountains and forests and cities and towns and maybe your house. Fully, fully blocking. Yeah, so fully, fully blocking. That's why this one was such a big deal. It was a total solar eclipse.

Okay. And so when we were thinking about this eclipse, I was like, okay, how would there be an interesting way for our show to cover this? And I started to notice this funny thing, which is that everything I was coming across was...

all about the sun. Understanding the sun is important for understanding our place in the universe. What happens to the sun, what we can learn about the sun, but also, if it wasn't about the sun, it was something about Earth and Earthlings, about what we'll feel or what it'll be like, about the atmosphere, about shadows, the light, the wind. And I was like,

wait, what about the moon? Like the only reason any of this is happening is because of the moon. And yet we're treating it like it's like the, you know, silly best friend who only has a couple of scenes. Treating it like the photo bomber in the way of the thing. Yeah. And I'm like, you're, this, the only reason this is happening is because the moon's causing it and no one's really talking about it. And I feel like that's sort of the case with the moon. Like it doesn't really get talked about that much.

It sort of gets short shrift. What are you talking about? People talk about the moon all the time. There was just like, wasn't there a whole thing about something that landed on the moon and fell over and everyone was like rooting for this thing on the moon? And I mean, just in general, NASA's going back to the moon. We already went to the moon. We haven't gone to the sun. Yeah, fair point about the sun. We haven't gone there. But I would just say like, I feel like you...

see the moon, so you think you know about the moon. But I don't know. What do you know? Tell me, what do you know about the moon? Craters. It has craters. Craters. It's some rock, I think, that is in orbit with us. It's circling us. Yeah, that's right. Does it...

Also spin, probably. Yeah. Yeah. Yeah. Okay. Sure. Okay, so just to sum up, your deep knowledge of the moon is that it's a round rock that orbits the Earth. A round rock, maybe. That may or may not spin.

Yeah. And has craters. You forgot about the craters. And it has craters. Right, right, right. I think you've just underscored my point. That I think we think, we feel like we know a lot about the moon because we spend a lot of time looking at it. But I would say that one, like that's kind of the collection of facts most people know about the moon. And that we've been there. That we've been there before. Yeah, exactly. So that's the other thing is that we often think of the moon in relation to us. Right.

And I just felt like when I realized this, I thought, oh, the moon is our closest neighbor. And it feels a little weird how little we know about it. It feels a little rude. And so I just started to wonder, can I know this cosmic neighbor more than it may or may not be round and rocky? Can I get to really know it? And so...

That led me to this idea that what we should do today is a moon show. Oh, nice. So, like, you want a profile of the moon. I absolutely want to profile the moon. And that is what we're going to do. We're going to do, like, a birth, a middle age, a death. Oh, I don't want it to die. Well, just stay tuned, Lulu. Stay tuned. Okay. So, the first part of our moon profile is...

comes from managing editor Pat Walters. Yeah, so I got curious about where the story starts. Okay. Like, where did the moon come from? I mean, I guess I've always thought it sort of just was something in space whizzing by and Earth's orbit caught it at some point. Maybe? I think I always thought that it was just like it's always been around, like the way it came from wherever the Earth came from, and they've always just been here together. Yeah, yeah. Good guesses. Not...

Correct. But those are both ideas that people have had for a long time. Yes. So there was sort of a number of different suggestions. This is according to Simon Locke. He's a research fellow at the University of Bristol in England. And I studied the formation and the evolution of planets. And the moon. And he says, for most of modern history...

People thought what you thought. Another idea was that the moon could have actually been sort of thrown out from the Earth itself. Like as the Earth was spinning, a chunk of it flew off and became the moon. An idea called fission. This was apparently a Darwin idea. Not the Charles Darwin, but his son, I believe. George. Yeah. He actually thought the Pacific Ocean was the hole left behind by...

by the moon when it flew off into space. Weird. Totally, yeah. And also wrong. What all scientists probably agree on is... Simon says what most likely happened was a bit more explosive. Yeah. The moon formed as a result of a giant impact.

Like a giant, like of what? Like a giant impact? What does that even mean here? Well, I should say there are a couple different versions of this theory, but the one Simon told me is wild. And it starts about 4.4 billion years ago.

Okay, so let's begin at the beginning. Okay, so just to set the scene. The overall picture is this. We're on Earth, and Earth is only about 100 million years old. So it's quite early in the whole history of Earth. It's really sort of still in the overture of Earth.

But even in these early days, it looked kind of like Earth does now. Just imagine a slightly smaller Earth. It probably had oceans and an atmosphere. This is Sarah Stewart. Professor at the University of California at Davis. And she and Simon explained to me that if you were standing on this baby Earth all those billions of years ago, gazing up into the night sky, it would have been full of stars just like it is now. The stars would look different.

because they won't yet have reached their current configuration, but it would be a starry sky. If you were staring up at it, at some point, a new little glimmer would have appeared in the sky. Next night, that dot would have gotten bigger. The night after that, a little bit bigger still.

And by the time it got big enough for you to tell what it was, which is a planet that's rushing towards Earth at 20,000 miles an hour, it would have consumed the entire sky and then smashed into the baby Earth. Dramatic. Yeah. The energy of the collision dumped into the Earth was the power of the sun.

And as a result... You vaporize, vaporize, so turn to gas, the rock of Earth. And, of course, the planet that hit it. And what's left is this sort of huge, swirling ball of gas. A big, spinning cloud. But made out of vaporized rock.

And Simon says this cloud is extremely wide. Ten times the size of the present day Earth. Incredibly hot. 2,000 Kelvin or so. And spinning super fast. The central part is rotating with a sort of three hour day. But it doesn't stay that way for very long. It's cooling really rapidly.

causing the vapor to condense into droplets of magma. Clouds are forming that are magma clouds. Sarah Stewart again. The magma droplets fall. As rain, basically. And the magma rain would have been torrential. Pretty quickly, the magma rain starts clumping together with bigger lumps of molten rock. And at some point, several of these lumps clump together and start pulling nearby stuff towards it and using that to grow in mass. And this lump of magma, this

will eventually become the moon. And the rest of this rocky gas cloud, that will become the earth. - Yeah, the moon is forming within this huge extended earth. - But this gas cloud version of earth- - It's contracting. - It's getting smaller as it cools and more and more of the gas turns into liquid magma until eventually, Simon says,

There's this sort of wonderful dramatic moment where the moon, which has been forming inside the gas cloud of Earth, would emerge from the Earth as sort of this newly born satellite and begin orbiting the Earth. And that, according to Simon and Sarah's theory, is how we got our moon. What? So it literally popped out of us? Yeah. Yeah.

And how long did this whole process take? The moon probably takes about, you know, on the order of 10 to a few tens of years to form. Ten years? Yeah, it's fast. What?!

That took less than one of us. Less than me or you. Less than our life. Yeah, and what I think is so amazing about this moment is that it didn't only give birth to the moon. This event is really significant, not only because it formed the moon, but it also actually formed the Earth, if you think about it. Like, before that giant impact, there was a version of the Earth, but it was different.

It was smaller. It was made of different stuff. It wasn't like tilted off at a slight angle away from the sun in the way that it is now. Like if the giant impact hadn't happened, it's not just that we wouldn't have a moon, but Earth wouldn't really be Earth in the way we know it. This moment when the moon became the moon is also how Earth became Earth itself.

Cool. Yeah, amazing. And not only were they born in the same moment, but they're also sort of twins. Like, when you look at a moon rock, which I actually got to do recently at a museum in Maine, it looks surprisingly familiar. In some ways, it's like...

not that dissimilar from rocks that I've held before. It just looked like a chunky gray and black rock. But obviously it's from the moon, which is insane to think about. But yeah, it is just a rock. And it turns out it's not just that moon rocks look like earth rocks, but if you were to break them open and examine their geochemistry, you would find that

Earth rocks and moon rocks are almost identical. Wait, can I just understand? Because, okay, so if you tell me they're the same. Yeah. I would just like, oh, of course, like everything in the universe or everything in the solar system was made at the same time. Like, of course, this thing is going to have the same as that thing. Like, is Mars the same? No, this looks quite different. I've got to hold a piece of Mars at that museum too. What?

Yeah, it's awesome. I believe this is a piece of Mars. And looks totally different than a moon rock or an Earth rock. Looks more metallic. Kind of red with green streaks through it. And according to Simon, is also geochemically very different. Because all of the things that were happening in the galaxy as the solar system was forming produce different amounts of different elements in different parts of the solar system. Yeah, exactly. So Mars looks different than Venus or Mercury, but Earth and the moon

and the moon look the same. And nothing else in the solar system looks quite the same. Why, if the moon and the earth are made of the same stuff and both were sort of born out of this one explosive moment, why didn't the moon just become a little earth?

Yeah, just because it's so much smaller. So it is only about 1% the mass of the Earth. But what that means is that the moon can't really hold on to an atmosphere.

If you open a bottle of air on the moon, very quickly that will get driven off into space. So it's not big enough, meaning it doesn't have enough gravity to hold that stuff down. Yeah. This is why when you see the astronauts bouncing across the surface of the moon, they can do that just because the gravity is so much lower.

And so the force that's holding on to our atmosphere just doesn't work as well when the gravity's that much lower. Okay. And without the atmosphere, none of the rest of it can happen. Oh, that...

kind of shocking and it makes you because it's like the whole you know so often we talk about like it's like oh the Goldilocks zone and it's like we're in the right spot like like distance from the sun and everything yeah exactly like it's like oh this is perfect for being habitable but then you look at the moon you're like oh if it makes life and

and Earth seem pretty special and rare and unique again, in a way. Yeah. Like, if that giant impact that gave birth to the Earth and the Moon had gone down a little bit differently, and some chunk of Earth had gotten blasted off into space and we had ended up smaller, we might not have been able to develop oceans and birds and...

Dogs. Babies. Music. We might have just ended up like a slightly bigger version of our cold, dry, airless twin, the moon. Managing Editor, Pat Walters.

All right, Molly, where are we? Where are we going from here? That felt kind of like a punctuation point. Yeah. Poor, dusty, dead moon. Honestly, by Pat's description, it sounds kind of dead to me, too. But I want to liven it up. I want to take you up there and liven it up. But there's nothing alive. What are you going to do? It's true. There are no palm trees or anything up there. But there is. It turns out there's just

so much stuff happening there. I am sort of a pressure cooker of facts and I just have to tell them to somebody. We will continue to moon you after this short break. Yeah.

Brains On is an award-winning science podcast for curious kids and adults. Each week, a different kid co-host joins me to find answers to fascinating questions like, what was the first life on Earth? Do dogs know they're dogs? And why can't we remember when we were babies? Plus, we have mystery sounds for you to guess, songs for you to dance to, and lots of facts, all checked by experts. You can listen to Brains On wherever you listen to podcasts.

We're back with reporter Molly Webster. So you are my captive audience. Are you ready? Let's do it.

So the moon does look a lot more like Earth than I would have expected. Huh. There are the craters that Lettif remembered. Right. Plus it has a bunch of mountain ranges. Okay. A point that's higher than Everest. Scientists have found moon caves. Ooh. And they've also found volcanoes that are billions and billions of years old. With lava? With lava. Whoa. It's very, very dry, old lava.

Okay. But really, the first thing I learned about the moon that really arrested me and made me want to know so much more about it is that the moon is covered in soil that kind of looks like sand. People will call it moon dust, but it's incredibly sharp. Like a little grain of it? Yeah, a tiny, tiny grain of it is like razor sharp. And it is that way because...

There's no wind on the moon or flowing water. There's nothing to erode and give you that soft, fine surface. So let's say you're on the moon, you take off your boots, and you try to do the beach, push your toes in the sand thing. Just the instant you put your foot down, did it get all cut up? Likely, yeah. And then probably before that happened, depending on where you were, it would either burn up or freeze. Yeah.

What? Because the temperature on the moon is super extreme. It's like one scientist said to me, it's either kill you hot or kill you cold. And that's because on the moon, if you're in the sun, it can be something like 250 degrees Fahrenheit. Wow. But if you're out of the sun, it can be negative 250 degrees Fahrenheit. Whoa.

It's like 500 degrees different. Yeah, it's a 500 degree difference. And the other thing is that on the moon, there is no sunrise or sunset.

What do you mean? You just turn from day to night or night to day. It just goes from light to dark or dark to light. Just like boom. What? And so it's kind of like just pulling up a blind and it's like, boom, there's the sun. Huh. Whoa. Okay. So, okay. So, so far we have, so there's the dirt, there is the temperature extremes, there is the lack of dawn and dusk.

And so what those temperature shifts do on the moon is they actually cause the moon to shake. Really? Yeah. There are moonquakes. What? So many kinds for actually so many different reasons. The ones I think are sort of super interesting are the ones that are caused by the tides.

With our tides? With our tides. Oh. And basically how that works is the moon causes the tides on the earth, which means the moon's gravity pushes and pulls the water in the oceans on the earth. Right. Which then changes the gravity of the earth, which actually fiddles with the moon itself again. It's like a feedback loop. Huh. What? And moonquakes are happening quite often. So just know when you look up there...

It's trembling. Stage fright. Oh, that's lovely. Yeah. I know. And I guess when you're, like when we're looking at the moon, the whole thing is kind of grayscale, right? Are there colors on the moon? Everything is pretty gray.

One thing I did hear was that when things land on the moon, like an asteroid or a meteor, there's like a whiteness to it. It's really bright. It's almost like newborn material that has hit from far away in the solar system. And then over time, as it starts getting pummeled by galaxies,

You know, the solar wind from the sun and different types of like charged radiative particles from space that those cause that whiteness to kind of like heat and condense and heat and condense. And then it becomes dark. And so the moon seems like it's a place of light and shadow. Yeah.

I feel like having this conversation with you, I think you were very successful in your premise. But more than that, like it's like it's this most of our images are either the ones we can see with the naked eye where it's this like comforting twinkle. It's the source of light in darkness. And it's so twinkly and forgiving and welcoming. And and then it's like, no, take off your shoes. Welcome to this place. The dust is daggers. You're going to you're going to bleed. Yeah.

If you scrunch into the dust. Temperature extremes. I mean, it is probably both twinkly and dagger dust and then also cold and alive and probably a thousand other things because we still don't know it that well. Like in all of time, we've only spent three and a half days up there.

It hasn't. We haven't actually spent that much time on the surface of the moon. Oh, really? Yeah. Three days in like a handful of hours. We've only...

That feels, I mean, quite literally like we've only scratched the surface. Exactly. We really don't know this friend of ours that well, actually. And like one of the things that came out of these conversations with scientists is just how many questions they still have about the moon and like how much we have yet to discover about it. And it's just like, you know, they would just rattle them off. Like, what is the history of impact events on the moon? Or what is the moon like below the surface? Or

Or why don't we ever see moonquakes on the far side of the moon? What is the little bit of lunar atmosphere that is up there made of? And how can the moon help us understand other planets? Like the list goes on and on. Like someone sent me a 120-page NASA book that was a lot about the questions on the moon. So it just feels like what we've done here is like, this is what we know about the moon day to day right now. Yeah. But...

that could just get blown up again as we learn more. But still, I just, I don't know. It's like instead of going to bed thinking about the little boys fishing off the moon, which is a nice image, I'm going to think about the long ago volcanoes exploding on it. Young lunar craters. That's what you're going to go to bed thinking about. I am. For real. It's beautiful. It's beautiful. Yeah.

That'll do it for today. I truly do think about the volcanoes on the moon now when I'm trying to fall asleep. I picture the different colors their lava may have been because apparently the lava was composed of different minerals. I picture them purple, yellow, and green. I'm not sure if that's accurate, but it's what I like to think about. If you want to send us a picture...

Of that, volcanoes on the moon or anything else that this show inspired you to think about, you can send it to terrestrials at wnyc.org. T-E-R-R-E-S-T-R-I-A-L-S-A-T-W-N-Y-C-D-O-T-O-R-G. Anyway, I hope all of you have a happy new year. And I'm going to just drop the hint that we have a special treat coming for you on New Year's Day. A little gift.

a little offering from the Terrestrials team. We hope you'll check it out. That'll drop early in the morning on New Year's Day. Until then, thank all of you for listening. Catch you once we've completed another lap around the sun.

This episode was reported by Molly Webster, Pat Walters, Becca Bresler, Alan Gofinski, Maria Paz Gutierrez, Sara Khari, Simon Adler, and Alex Neeson. Produced by Matt Kielty, Becca Bresler, Pat Walters, Maria Paz Gutierrez, Alan Gofinski, and Simon Adler. It was edited by Becca Bresler and Pat Walters, fact checkers Diane Kelly and Natalie A. Middleton, original music and sound design by Matt Kielty, Becca Bresler, Jeremy Bloom, Maria Paz Gutierrez, and Simon Adler. Mixing help?

from Arianne Wack. Special thanks to Rebecca Boyle, whose new book is Our Moon, How the Earth's Celestial Companion Transformed the Planet, Guided Evolution, and Made Us Who We Are. Also to Renee Weber, Paul M. Sutter, Matt Sigler, Sarah Noble, Chucky P., Sarah Stewart, and Patrick Leverone and Daryl Pitts at the Maine Gem and Mineral Museum in Bethel, Maine.

Radiolab is supported by the Simons Foundation, whose In the Path of Totality initiative celebrates the April 8th total solar eclipse. More at inthepathoftotality.org. Thank you for listening. Until next time.

Hi, I'm Emma, and I live in Portland, Maine. Here are the staff credits. Radiolab was created by Jad Abumrad and is edited by Soren Wheeler. Lulu Miller and Latif Nasser are our co-hosts. Dylan Keefe is our director of sound design. Our staff includes Simon Adler, Jeremy Bloom, Becca Bressler, W. Harry Fortuna, David Gable, Maria Paz Gutierrez, Sindhu Jnanasambandam, Matt Kielty,

Our fact checkers are Diane Kelly, Emily Krieger, and Natalie Middleton.

Hi, this is Tamara from Pasadena, California. Leadership support for Radiolab science programming is provided by the Gordon and Betty Moore Foundation, Science Sandbox, a Simons Foundation initiative, and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.