Daniel and Kelly’s Extraordinary Universe - How do planets get rings?

Episode Date: November 3, 2022

Daniel and Katie talk about planetary rings and what they tell us about the history of the solar system.See omnystudio.com/listener for privacy information.

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Hey, Katie, help me out with some research for an upcoming episode. All right, as long as you don't put me in that collider of yours. Not this time, but, you know, in general, no promises. So just make sure you always read the waiver very carefully. All right. I'll wear a helmet. So what are we researching? Well, I'm trying to understand rings.

All right. And how can I help? Well, you got engaged and married recently, didn't you? Yeah, during the pandemic. I had a Zoom wedding. It was really fun. And did you get a real ring or a digital zoom ring? I got a real ring, not just an NFT pointing to a ring.

Yes, I have a real ring. And tell us a little bit about it. Is it made out of icy particles or mostly dust and rocks? It was actually grown in a lab, lab grown diamonds, which is pretty neat to me. Well, I wonder if podcaster and planetary rings have anything in common. Yeah, I wonder the same thing. You know, actually, my husband later told me that he had the choice to get like a ring made out of a meteorite. So sometimes they do converge.

Wow, that'd be awesome, a little bit of space on your finger. Well, we will have to invite Saturn on the podcast to ask how it got its rings and when its fiancé proposed to it. Saturn's got the best bling in the solar system. Hi, I'm Daniel. I'm a physicist at UC Irvine, and I do research at the large Hadron Collider. I am Katie Golden. I host Creature Feature, a biology podcast. So I'm not exactly a physicist, but I have used a who. a hoop before so I feel fairly confident I can talk about Saturn's rings today. Oh, I think that makes you an engineer, doesn't it? That's right. Just get me some tape and a few paper clips and boom,

I'm an engineer. Well, I actually don't wear a whole lot of rings. I just have this one wedding ring, which my wife and I picked up two days before our wedding on the streets of Berkeley for about five bucks. And I think at the time we were like, oh, this will work temporarily. And here we are, 20 years later, I'm still wearing the same silver ring. Oh, that's so sweet. I love that story. Yeah, it's a nice memory. It helps me understand where I came from. And, you know, in the same way, we can look up at the night sky and study the planets and use their rings to try to get an idea of like where they came from. What is the history of this planet? How did it get that ring? Who gave it to it?

And, you know, what is that wedding going to look like? So you're saying because my ring was made in a lab that I too was made in a lab. Maybe your love was grown in a lab, you know, which doesn't make it any less authentic. I'm a big fan of labs and research. It's very romantic. Test tube romance. And welcome to the podcast, Daniel and Jorge, explain the universe in which we try to grow your understanding of the nature of this universe that we find ourselves in. We cast our minds out into the deepest, dark,

of space and try to ring out understanding of everything that's out there in the universe and we zoom on into the tiniest little things between our toes and under our fingernails because we want to understand the fundamental nature of the universe the nature of space and time itself and matter and energy and all those tiny little bits which in their towing and froing come together to make the universe that we know and love my friend and co-host Jorge can't be with us today he is on vacation, but we are very pleased to have the be ringed, be jeweled, be blinged, Katie, to join us today. Well, thank you for ringing me up for this episode. Yes, I'm very excited. I love science, but that doesn't mean I can't appreciate some good old-fashioned cosmic jewelry.

Well, one thing I love about jewelry is that it really does tell a story. You know, you talk to somebody and you see them with earrings or with a necklace, you know that that has a history. You know, Maybe somebody bought for them, or they got it for some big event, or maybe they inherited it from their family. And it tells like an even deeper story about where they came from and their family history. So it's like everybody who's wearing jewelry is walking around telling little stories about themselves. Yeah, I love that. Or it bears an ancient curse. Are we going to take a deep, dark turn on this podcast?

I don't know. Is Saturn cursed? Is that what we're going to discover? Maybe aliens visited the solar system and had. of war with the octopi living under the oceans of insolatus and the rings are just the leftover remnants of that interstellar conflict. That's very spooky and I would love that story for a ring that I had that it was made by some kind of intergalactic war. I think it is one of the things about the solar system that really adds a bit of magic to it, adds a bit of artistry

to it because of course I think all the planets are lovely but they're all orbs. You know, they're There are all these roughly, of course, not exact, precise spheres, but, you know, roughly spherical. But then you have these rings. And it always, when I see Saturn, that gives me a feeling of awe about the mystery and artistry of space that I don't necessarily get with other planets. Absolutely, because it's so easy to grab onto, you know, it's so visible out there. And it must have been an amazing moment in 1610 when Galileo looked through his telescope. and saw the rings of Saturn. I mean, how shocking to discover that planets can have these incredible disks.

You know, these things are like 10 times the size of Saturn. We'll talk later about how Saturn might have rings that go out like 200 times the size of its radius. It's an incredible thing. Like, I have this little tiny ring on my finger. Imagine if I was wearing a ring that was like 200 times the size of me. You know, some might say that's a little overstated. It would be a statement piece for sure.

You know, I was actually just in the Gellon. Galileo Museum in Florence. And when you think of Galileo with his telescope, he's often depicted with this small, you know, telescope he can hold in his hands. But you look at the actual telescopes he used to observe Saturn. And they were huge. Yeah, he wasn't the inventor of the telescope, but he was the first one to really perfect it and then to turn it up on the skies.

And so he got like the biggest first scoop of all of these discoveries. You know, he saw the moons of Jupiter. He saw the rings of Saturn. He saw mountains on the moon. what a moment to really look out into the universe. And I think that one of the most interesting things for me about it is that they do reveal the history of the solar system. You know, we look out onto the night sky and we want to understand not just what's out

there, but why it's out there and why it looks the way that it does. And so anything that's weird or strange or unusual that's not just like a ball floating in the sky, lets us ask the question, how did that get there? How long can that live? What does that tell us about the history of the solar system? Have those rings just been there for the last million years? Have they been there since the beginning of the solar system? Why does Saturn have rings and not other planets?

Or do they, right? There's just so many immediate questions that you can ask when you see these rings. And then those questions open the door to try to understand the formation of the solar system. The other aspect, which is super fascinating for me, is just thinking about what physics can do. You know, you throw a whole bunch of stuff out into space and it forms stars and it forms planets, but not just that, right? It can also do these other incredible things. And it's all these fascinating little wrinkles, these little bits of bling that really show us

what gravity is capable of and the interplay between gravity and all the other forces. So as we'll see on today's episode, these rings will teach us a lot about the nature of the solar system and the universe that we live in. And so on today's episode, we'll be tackling exactly that question. How do plant? get rings. Okay, I'm going to stop you right there because I think I have the answer. It is

aliens, giant aliens doing ring toss with our planets. Or maybe it's hula hoops from a leftover enormous alien birthday party. We're basically their garbage bin. But it's an interesting question, not just why are there rings, but how do planets get rings? Where do they come from? Why do some planets have rings and others don't? Why do some planets have more moons and fewer rings? What is the connection between rings and moons? Can moons have rings? Can rings exist on planets in other solar systems? Is our solar system weird for having this incredible planet with these huge rings?

Or are we weird for not having rings around every single planet? These are the kinds of questions we can now ask about our solar system because we have looked out through our telescopes into even other solar systems around other stars to try to get an answer to the question of is our solar system strange? Or is our solar system totally vanilla and typical? I find that an interesting way to describe. If our solar system is similar to other solar systems, we're just boring and vanilla. Well, it's a deep question, right?

Like, are we typical? Are we boring? If alien scientists are studying the whole galaxy, would they find us an interesting case study? Or would they be like, oh, yeah, another one just like all the other 65 million systems that I've already studied, right? We'd like to think that we are special in some sense. We'd like to imagine that we are at the center of the universe. We are unusual. We are sparkling.

We are exceptional. On the other hand, I'd like to believe that we are vanilla, that we are boring. Because that means it's probably more of us, right? That means it's probably life everywhere. One of my favorite things about this kind of question, is our solar system typical or not? Is that the answer is fascinating either way. Either we're incredibly unusual and then we get to ask why or we're not, in which case we got lots of neighbors. Yeah.

So you would favor us being basic. solar system with our ugg boots and our Saturn's rings, that is kind of an interesting personality, quick personality test. Like, would you prefer our solar system to be unique and special and us to be the only planet with life? Or would you prefer us to be run of the mill? Lots of solar systems like ours out there and not feel so alone. I agree with you. I hope we're basic so that we've got some friends out there. Exactly. We can't answer that question. directly today because our telescopes are not powerful enough to look through the atmospheres of exoplanets, but we can look in our own backyard and try to understand how our solar system formed

and if there's anything in it that we cannot explain. And it's an incredible piece of science to look around you and understand how it came together, to build a model for the processes that could have formed such incredible structures and to think about how long they might have taken. You know, we've done something similar here on Earth by looking under our feet and asking questions like, do we understand how the Earth formed and how the mountains have formed and all the ridges that we see and the layers of rock? And those things are clues, the clues that led us to understand something really shocking, that the Earth is billions of years old, not thousands of years old, right? We have the evidence all around us to reveal the story of the

formation of the solar system, but not just here on Earth, out there in space. And one of the funest bits is to look at the rings around those planets. So that's what we're focused. on today and I was curious whether people understood rings whether rings were still a big source of mystery or people thought they pretty much understood where they came from so I went out there to our cadre of internet volunteers who answer my random questions without a chance to prepare which gives us a sense for what people know what they think about and what they want to hear about if you'd like to participate for future episodes please don't be shy just write to me to questions

at danielanhorhe.com before you hear these answers think to yourself do you have good idea of where rings come from on planets. Here's what our listeners had to say. And I'm pretty sure that I learned about this, that it's asteroids colliding near the planet itself and the remnants of those asteroids going into orbit and creating a sort of disc. I think the two classical ways are by planets capturing space debris that's just floating through the solar system or by recapturing. debris caused by an impact. But I've also heard of a moon orbiting Saturn, I believe, that has

a geyser. And when the geyser spits out water, it forms into ice crystals. And then that joins the rings of Saturn. So maybe that's another option. Well, the rings are kind of like small satellites, I would say, like small moons. Like we have the moon small, really tiny moons that get around the planet. Each planet has its own way of doing the rings. Well, I wanted to say that planets can get rings if they collide with big rocky bodies, but I don't know how that would work with gas giants

and how they got their rings. So I'm going to guess that it's just stuff that is left over from when the planet was formed. And it was just stuff that was so far away when it was being formed that it didn't become part of the planet, but it was still close enough to be influenced by the gravity of it. I'm almost certain it's got to do with the accretion process of when a planet's formed

and the attraction of stuff towards the planet. Apart from that, I'm not really sure, actually. I think planets form when like a heavy metal gets caught in orbit around a star. So I think something similar happens around the planet debris and maybe rocks or particles of ice or something gather around a planet in much the same way that planets gather around stars. Those all seem like really intelligent answers, but I still kind of like my giant alien ring toss theory. We'll put it on the list as the dark horse theory that might storm out at the end if we can't explain it with any of the other theories. So it seems like there are so many options for what these rings could be made of. How on earth are we, or I should say how in our solar system,

are we going to be able to figure out what exactly they're made of if there are so many different theories, so many different options for what they could be made of? Yeah, it's a great question. I listen to these answers and it seems to me like they form in roughly two categories. There are some folks that say that it's basically debris from other stuff that broke up. Like maybe you had comets or moons that smashed into each other and basically just made a big mess, you know. But then you have to wonder like, why don't those things gather together to make a new moon or to make a new comet or something?

And the other category is like maybe it's just left over from when the planet was formed. The same stuff that formed the planet, but some of it didn't get into the planet. So it seems like those are two different categories of ideas. And you ask a great question. How could we possibly ever figure this out? how could we know what the history is of the solar system? And the answer is that, of course, we can't just like watch a video of its formation, though we'd love to, but we can just look around us for clues. We can try to build up models for how rings might form and then compare the details of those models to what we see.

So the short answer is we need more money and more data to measure these rings, to look closely at them, to see what they are made out of, how much mass they have, what their distribution is. and the more detail we can get about what they look like and what they're made out of, the better we can compare them to predictions from our theories about how they were formed. I mean, it sounds like a worthy use of funding. However, might I suggest an NFT of a farting panda instead? I'll put that on the proposal list and see where it goes.

So when we're talking about rings, like what is it? Because, you know, my wedding ring is this solid band that sits around my finger. A hula hoop is this very thin torus that you kind of use the motion of your hips to keep moving around with its momentum. So what are the rings that are around Saturn? Are they spinning around like a hula hoop? Are they just kind of sitting on it like my wedding ring? It's a great question.

And when it comes to astronomy, you always have to start with the definition, which immediately puts you into a swamp because nothing falls nicely into. clean categories out there in space. You know, what's a planet? What's a minor planet? What's a centaur? A lot of these definitions come from history because we didn't really understand what was going on and we just sort of named things randomly and then we were sort of stuck with different

categories and so often it can be a bit of a mess. Well, we're lucky in biology because species is super simple and never has that problem. Exactly. Nature doesn't confine itself to our categories. What's out there in the universe is not things that fall into crisply defined different. from boxes. It's a whole spectrum of stuff, right? And so we just go to put these arbitrary definitions out there so that we can talk to each other about it. So one of the most common definitions of a ring is a disc or ring composed of solid materials such as dust or moonlets.

Aw, moonlets. That sounds really cute. What's a moonlit? A moonlet is like a little moon, you know, like a little moonito. Oh, little baby moon. Yeah, exactly. A little minor moon. Immediately you understand these rings are not actually a solid object. It's not like a hula hoop, right? Or the rings around Saturn are not huge circles. They're actually a bunch of tiny little particles, a bunch of chunks that are moving in the same orbit.

And so from far away, it looks like a ring. Of course, it looks like a single hula hoop, for example, or a wedding ring. But if you zoomed in closely, you see it's actually a bunch of individual pieces that are not touching each other. So cartoons have lied to me. I cannot drive a race car or a skateboard around

the rings of Saturn. That's right. You can't do Mario Kart on the rings of Saturn and you would fall right through. It's very disappointing. Cartoons play it real fast and loose with physics. I'm discovering. And so basically a ring is just like a disk of material in a single orbit moving all around. And that makes it a little bit unusual because orbits are usually for one object. You know, like the moon orbits the earth and there's nothing else in the moon's orbit. It's not like there's something else on the other side or the earth is orbiting the sun and there's nothing else. And there's nothing else in Earth's orbit, right? It clears its own path. So it's a bunch of individual things sharing a single orbit, kind of like a lazy river at a water park. Exactly. Sort of like a lazy river. And once you define

it that way, you can ask questions like, well, what counts as a ring? You know, does it have to be natural? For example, like Earth has a bunch of stuff out there in space, things we have launched out there, a bunch of satellites in the same orbit. You know, zooming all our around. Does that count as a ring? Have we built our own ring system around the earth because all the junk that we put out there in space? Nobody talks about Earth's rings, but technically, you know, it seems like that might qualify. There's no like minimum mass requirement for the rings as far as I can tell. So we're one step closer to Halo, am I right? Hi-fives, everyone who plays computer games. Another requirement for rings usually is that they are pretty flat, right? If you

have just like a swarm, a spherical swarm of objects, then your planet's just surrounded by junk. A ring is typically something which is flattened, right? It's more like a disc. And this already shows off what's going on with gravity. You know, gravity is pulled the planet together and it's spinning and it's also pulled the ring together. And the reason that rings form in disks is the same reason that the solar system is a disk, right? That most of the stuff is spinning in the same direction along the same plane. And that's because of conservation of angular momentum. that spinning keeps spinning and if gravity pulls it together it keeps spinning it's harder for gravity to pull it together towards the spin axis than along the spin axis the same way for example that like

earth resists falling into the sun because of its speed because of its angular momentum right but the earth didn't resist falling into the sun's plane so gravity is free to compress things down into a flat disc but angular momentum keeps things spinning and keep things from falling in that's what gives rings, these sort of flat structure. So that's another typical thing we expect of rings that they're not spherical distributions of stuff. They're like these flat discs. Is that sort of like if you pile a bunch of peas on a plate and then spin the plate, all the peas are going to scatter outwards and get everywhere, but in sort of a flat circle? I've never done that experiment, but yes, in my mind, that that's exactly what would happen. You don't do that. We call it

pee spinning in this household. But in our solar system, of course, is gravity and gravity would hold those peas in, right? So those peas would end up in like a circular orbit exactly instead of like a bunch of different orbits. And so that's why the planets are all roughly in the same plane because they have the same spin from the original blob of gas and dust that formed our solar system. And so that's already a clue that tells you something about the origins of these rings. Because if rings were formed with the planet, then you would expect them to have roughly the same alignment, the same spin as the planet. And if they were not, then they don't necessarily have to have that same spin. They came in from like a comet that smashed

into the planet or broke up a moon. It might give you a different kind of distribution. So already that's a clue that tells you something about where rings might have come from. Oh, that's really interesting. So when you have debris from a planet's formation, everything's spinning at the same rate sort of going with the same flow but then if you have something smash into a planet release all these all this debris and it starts orbiting the planet it doesn't need to spin at the same rate as the planet spins just like our moon our moon doesn't spin at the same rate as earth right that's right no it does not right so that would suggest that the moon was not necessarily formed when the earth was formed right exactly and we think that the moon is the

a result of a huge collision that something came and smashed into the earth and released an enormous amount of debris which then coalesced into a moon right so that after that collision earth may have had a very large cloud of debris which then probably coalesced into a ring system which then further gathered into a moon so our moon may have once been a ring so do we know with the rings of saturn if they are moving at the same rate as saturn or at a different rate? The rings of Saturn are especially complicated because there are so many rings and some of them are moving with Saturn and some of them may actually be rotating the other direction. It's really tricky and complicated and we'll dig into it in a moment when we talk about how the rings of planets are formed, the various theories and the pieces of evidence for and against. But first, let's take a quick break.

All right. I'm going to try to imagine those rings moving in different directions without getting seasick during. the break. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys.

Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion, actually impelled metal glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged,

and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of law and order criminal justice system on the iHeart radio app apple podcasts or wherever you get your

podcasts my boyfriend's professor is way too friendly and now i'm seriously suspicious oh wait a minute sam maybe her boyfriend's just looking for extra credit well dakota it's back to school week on the okay story time podcast so we'll find out soon this person writes my boyfriend has been hanging out with his young professor a lot he doesn't think it's a problem but i don't trust her now he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy?

That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him

because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Smokey the bear. Then you know why Smokey tells you when he sees you passing through.

Remember, please be careful. It's the least that you can do. It's what you desire. Don't play with matches. Don't play with fire. After 80 years of learning his wildfire prevention tips, Smokey Bear lives within a song. Learn more at Smokey Bear.com.

And remember, Only you can prevent you. Wildfires. Brought to you by the USDA Forest Service, your state forester, and the ad council. Hello, puzzlers. Let's start with a quick puzzle. The answer is Ken Jennings' appearance on The Puzzler with A.J. Jacobs. The question is, what is the most entertaining listening experience in podcast land? Jeopardy-truthers who say that you were given all the answers believe in? I guess they would be kenspiracy theory. That's right. Are there Jeopardy Truthers? Are there people who say that

it was rigged? Yeah, ever since I was first on, people are like, they gave you the answers, right? And then there's the other ones which are like. They gave you the answers, and you still blew it. Don't miss Jeopardy legend Ken Jennings on our special game show week of the Puzzler podcast. The Puzzler

is the best place to get your daily word puzzle fix. Listen on the iHeart radio app, Apple Podcast, or wherever you get your podcasts. All right, we are back. I got a little dizzy trying to think about Saturn's rings, some moving in one direction, others moving in another.

It's pretty trippy. But yeah, I still have a lot of questions about these rings. We're talking about like how maybe they're. formed, whether they're formed when the planet forms out of basically the same stuff that the planet is formed out of, or if it is made out of kind of some outside stuff, stuff that wasn't around when the planet was formed, like by a collision, like how maybe our moon was formed. Do we know, like, what stuff is inside of these rings? And how do we know what is inside a ring without actually going up there and taking a scoop of it? Yeah, that's a good question.

we can do is we can look at it through a telescope and see what kind of light it reflects. Is it opaque? Is it transparent? Is it transparent to different kinds of light? Each planet reflects sunlight, but it also emits particles. And so we can see whether the rings create shadows in some sort of the wind of Jupiter or the wind of Saturn. And we have also sent probes out there. And these probes, we'll talk about them in a minute, have made some really startling discoveries by getting very close up to these rings. But first I want to talk about sort of the general question like talked a minute ago about the earth's moon and how it used to be a ring and you know in my mind one of the first questions is like why do sometimes things form

together into a moon and sometimes they don't and they stay as rings or is there like a process there where every ring eventually turns into a moon it's really fascinating in question and it turns out to be totally dominated by the gravity of the planet and how far you are away from that planet Hmm. So Saturn's rings could conceivably have turned into moons if they had been in a different situation. Conceivably, yeah. And it actually turns out that Saturn's rings have little moonlets inside them that move around and shepherd them and keep them apart. So it's really fun. But the crucial thing that determines whether something is a moon or a ring, whether it gets torn up into little bits or whether it gets clumped together by gravity is the gravity of the host planet. You know, you have a bunch of

stuff out in the middle of space, gravity will eventually gather it together. Gravity is very, very weak. It's the weakest force we know, but it's also very patient. And eventually, it will pull things together to make a clump. So you might expect that all rings would be transient, that they would be eventually just gathered together into a moon. But that's not necessarily the case because of the gravity of the planet. This gravity does more than just pull the moon in to orbit or keep the rings in orbit.

He can also pull them apart. And this is a concept we've talked about on the podcast before. are called tidal forces. The idea is they have a very strong source of gravity like Jupiter or a black hole or the sun or even the earth and it's pulling on you, right? But the strength of its force on you depends on how close you are to that object. So if your feet are closer to the sun than your head, then the sun is pulling on your feet harder than it's pulling on your head. And effectively that means it's trying to pull your head off of your body. Well, that's lovely. Nobody ever said the was a nice guy. Oh, I know it. I know that right now in July. And that's happening right now.

If you stand on the surface of the earth, then the earth is literally trying to pull your head off of your body. Now, we've evolved with strong enough next to resist this, this, and the tidal forces here are not that strong. Yeah, take that earth. But if you're in a situation where the gravitational forces get strong very quickly, so the force on your feet is much stronger than the force on your head, you can be torn apart. And if you're near a black hole, for example, where this is very dramatic, this is what we call spaghettification. You can get pulled apart into tiny little pieces. The most delicious way to describe a horrific death.

Exactly. And we've seen this happen. When Comet Shoemaker Levy came into the solar system in the 90s, it was headed for an impact with Jupiter. But before it hit Jupiter, it made a near miss, and Jupiter pulled it apart into 26 pieces. So you had this comet coming into the solar system, which got shredded by Jupiter's gravity. Then it went around the sun and it hit Jupiter 26 different times, which is pretty awesome for everybody to look at these huge fireballs, the size of the Earth.

But for our sakes today, this is just a demonstration of tidal forces. So a planet doesn't just pull stuff in and keep it in orbit. It can also tear it apart if you are close enough. I see. So because gravity gets weaker the further away you are from something, but stronger, the closer you are to something, if part of you is far enough away that it's pretty weak and it's not pulling on you, but the other part of you is closer and it's tugging on you more strongly, that part of you is going to get kind of ripped off of the other part of you. Is that what's

happening to these poor baby little moonlets? That's what's happening to those rings. So if you're a big blob of material and you're too close to a planet, you cannot form a moon because the planet will just keep tearing you apart. If you're far enough away, then you can form a moon. So there's a limit there. It's called the Roche limit, R-O-C-H-E, after a scientist who came up with this idea. If you are closer than the Roche limit, then you cannot form a gravitationally bound object because the gravity of the planet is stronger than your inherent gravity to hold yourself

together. If you're out past it, then the tidal forces are so weak that you can clump the ring together into a moon. So past the Roche limit, you get moons closer. in then the Roche limit, you get rings. So Saturn's rings are too close to Saturn itself to form the moon, whereas our moon, which maybe started as a ring, was far enough away, that it could do its own thing without Earth overbearing and deciding its fate for it.

That's exactly right. And it depends a little bit on what you're made out of. The Roche limit itself is technically just assuming you're held together gravitationally, but things can also be held together in different ways. You know, if you have a blob of diamond, for example, as opposed to a loose bag of golf balls, then the diamond is going to be able to hold itself together closer to a planet than your bag of golf balls.

I wish my wedding ring was a bag of golf balls now. That would be fun. I hope your husband listens to this podcast to hear you complaining about his gift to you. This beautiful gift of love. I wish it was a bag of golf balls. Well, in the case of our system, for example, you know, the moon hold itself together, but if it was closer to the Earth, the Earth would shred it.

Our moon is about 385,000 kilometers away, and the Roche limit for the Earth and an object the size of the moon is about 10,000 kilometers. So the moon would have to be much, much closer to the Earth in order for the Earth to pull it apart and make it into a ring system. And so that's why the moon is a moon. In a similar way, you know, the Sun has a tidal force on the Earth. It's pulling on the part of the Earth that's closer to it, stronger than it's pulling on part of the Earth that's further from it. So the Sun is trying to rip the Earth apart. But the Earth is too far away. It's too strong. It has structural integrity that keeps the Sun from destroying us. We're about 150 million kilometers from the Sun. If we were just less than a million kilometers, then the Earth would get

pulled apart. It would get torn into a ring system around the Sun. Seems like planetary bodies are like complicated friendships. You've got to set strong boundaries or else you're going to get destroyed. Exactly. So you just, you got to know where you are. You know, you've got to have the conversation sometimes to figure this out. Listen, son, we love you. You provide us with energy that gives us food. But, you know, if we're too close to you, we all die. So you know how it is. And so this is the basic physics of it, right? You get too close. You turn into a ring. You stay far away. You can be a moon. But that doesn't answer the question of like where these things come from because there's still two basic ideas there. One is that some of the stuff is

from the original formation of the solar system. You know, you have this huge cloud of gas and dust. A lot of it formed the sun. Some of it clumps together to form planets. You can imagine that some of the stuff is close enough to the planet that it gets trapped by the planet's gravity, but not so close that it actually gets sucked in. It has like too much angular momentum to actually fall to the Earth. You know, the same way like the Earth right now has particles that are trapped by its gravity

and also particles that are not. the Earth's atmosphere is boiling away into space. So you can imagine that at the edge of the planetary formation, there might have been particles there that didn't quite get captured by the gravity, but they're too close to clump together into their own moon. So that's one theory of how these rings get formed. They're like the fastest moving bits of the planet, didn't quite get captured,

but they're not fast enough moving to be like out on a further orbit far enough away where they could make their own moon. So the other theory has to do with something, that wasn't there during the origin of the solar system coming in and creating some debris around Saturn or whatever planet decides to make a ring. Yeah, so the first theory that they are made with the planet that suggests the rings are old, right? That they're as old as the solar system, like four and a half billion years old.

The other theories you say is that rings could be fairly new. Maybe they're sort of transient. Maybe they come from a cataclysmic event. Like something comes in and smashes into a moon or break. up a moon and that moon gets shredded into pieces and maybe it'll eventually get gathered back together into a new moon, right? So these rings might be short-lived events in that scenario, like a comet or an asteroid or something else. Might have created this huge mess, but the solar system will eventually clean itself up. But if it's in that sweet spot where it's still getting

shredded by the planet's gravitational force, but it's not so close that it doesn't get sucked into the planet's going to stay a ring, right? It could, right? It depends a lot on the details. Like, you could have a moon that was past the Roche limit, but then an impact creates a huge amount of debris, some of which falls into the sort of the ring zone, some of it could fall into the planet, or some of it could stay out in the sort of moon area and form a new moon. So you're right that you could also form rings, which then can be fairly stable. If you have a collision which creates a lot of mess, and some of that mess is stable in the sort of ring zone, then you can have a long living ring. That's how I like to do.

describe myself as stable mess. So that seems really difficult to kind of parse out those theories, I guess, without taking a closer look because stuff that comes crashing into Saturn and stuff that was originally there when Saturn was formed may from a distance look pretty similar unless we keep investigating, right? Exactly. And so to understand where a specific ring comes from, We need to look at that ring in detail and we need to think about, is it made out of the same stuff as the planet or something weird and new? Does it look like it's aged a lot? And does it look like it's a fairly fresh result of a collision? Or does it look like really weathered from lots of solar system radiation and collisions?

We can also understand the distribution of the rings, like where the mass is in the ring and build models to see like, is it stable? Could it hold itself together? Could have developed into this over time? So for each ring, the crucial thing is to get as much information. as possible, and then to build these models to try to explain what we see, and that'll help us discriminate between various scenarios. And a key thing to understand is that it might not be one answer for every ring. It might be that there are some rings that are ancient and other rings that are very fresh. What is the difference between what we can tell with like a telescope

here on Earth versus something we send out to get a closer look? There's no fundamental difference, right? We can do the same things here as we can do getting close. But of course, the closer you get, the better your data. You can resolve these things better just because you're closer up. So you don't need like as big a lens. You can also bring instruments closer up, you know, things like spectrometers to measure these things. There is one thing that you can do by sending a satellite

that you can't do from Earth, which is to try to measure the mass of the rings. I will talk about it when we get into Saturn. When we sent Cassini out to Saturn and actually dove in between the rings and the planets and measure the effect of the rings gravity on Cassini itself as a way to measure the mass of the rings. And that's just not something you can do from Earth. That's something that requires perturbing it gravitationally, throwing something out there,

which is going to actually interact with the mass of the ring itself to see how much stuff there is in there. Is it dangerous for the satellite to be in the rings? Like, is it going to get hit by a bunch of little space BBs? It can be dangerous, but it dove in between in one of the gaps to avoid collisions. Yeah. And you know, these things seem smooth. They seem like, oh, it's a continuous blob. But actually, there's lots of gaps in between them. So you could fly through the rings and survive, though. You know, it would be a little bit harrowing. I see. Well, brave little satellite. But we don't have any satellites that have like a little extendable ice cream scoop that scoops up some of the stuff in the rings. So how do we know what they're made of? And do we know what they're made of? So we know a little bit about what they're made out of based on our models, you know, what's in the solar system and also based on our studies of what light reflects off of them.

That's really our best way to understand what's in them. Mostly we think that the rings are made out of ice and dust. And that's also, you know, what the planets are made out of. The planets when they were forming were made out of the basic ingredients of the solar system, which was dust and ice and gas. Now, most of the gas got slurped up by the sun or by the gas giants themselves, and so you're left over with ice and dust. Now, in the inner solar system, a lot of that ice is vaporized, but in the outer solar system, past what we call the frost line. It was cold enough for that ice to stay solid, and so it helped form some of these ice giants. And so the rings are made out of that same stuff, mostly ice and dust.

Beyond the frost line, there's a lot of ice in them. Saturn's rings, for example, are mostly icy particles. And closer in, you expect more rock and dust in rings. So when we're talking about ice, you know, I think of, I mean, especially today because it's so hot, but I think of a big chunk of ice that I would put in my drink, like in my glass. But is that what this ice is? Are they big chunks? Is it sort of like ice crystals and a bunch of them?

What form does this ice take? So when we're talking about ice, we do mean water ice. This is like H2O, but there's also other kinds of ice, you know, ammonia ice and other kinds things. So when chemists say ice, they mean a wide range of stuff, not just the stuff you put in your summer cocktails, but it does include, you know, drinkable water ice. Like if you are building a colony around Saturn and you need water, like the rings are a great source of water the humans could actually drink. And it comes in chunks. You know, some of these things are as small as a centimeter, like cute little ice cubes that would fit in your glass. And some of them are like

are as big as 10 meters. So, you know, like really pretty big. big chunks. You'd have to be a giant to enjoy that in your lemonade. So I could in theory ride that satellite hold out a glass lemonade and get some ice in there as long as I don't get pulverized by a giant ice chunk. That's great news. What's the dust made out of? So the dust is just, you know, silicates. It's like rock, the same kind of stuff that the earth is made out of. Like, it's just basically dirt, you know, huge chunks of rock and dirt. And some of these things have organic compounds in them. You know, we wonder about like the formation of, life. One of a really interesting area of research is like where do organic molecules come from

the basic building blocks of life? Are they only found on Earth or are they found all over the universe? So looking at the rings helps us understand that kind of thing. We also study asteroids and comets. And what we find is that there are organic compounds all over the solar system. These basic building blocks are not rare. They're everywhere. So you've got ice, which is, you know, the solid form of water and you've got organic compounds. Is there? a reason why we wouldn't expect there to be life on Saturn? Is it because the ice would be solid or is it because Saturn's surface is not hospitable to the formation of life? I don't know if there's life on Saturn, of course. If there is life on Saturn, it would have to

be quite different from life on Earth because the environment on Saturn is very different, right? Saturn is a gas giant and so it's very high pressure. There's a lot of radiation on Saturn. So it would have to be quite different. But one of the moons of Saturn, Insulatus, which we've talked about, has an icy shell and underneath is a liquid ocean. And that liquid ocean is partially kept liquid by those tidal forces. Saturn is squeezing that moon, which keeps it from freezing. It's imparting energy to it, sort of like by massaging it with its gravity. So in the water under the surface of Enceladus might be some life.

We just don't know. But the rings are mostly frozen. They're mostly just big chunks of ice. And, you know, there's a fascinating sort of geometrical structure here because they are very, very wide. You know, these things are like 70 to 100,000 kilometers wide. We're talking about Saturn's rings. But in terms of thickness, they're like 20 meters thick. So there are tens of thousands of kilometers wide and only tens of meters thick.

If you had a sheet of paper of this thickness, they would have to be like a kilometer wide sheet of paper to have the same proportions as Saturn's rings. That's an idea for your science project to elementary schoolers. A model of Saturn's rings. And you know, you can see Saturn's rings from Earth, which is incredible, without a really powerful telescope. But there's a lot more rings to Saturn than you can just see. There's three really bright rings, which astronomers have cleverly named A, B, and C, of course. But there are other rings that go out even further, out to the G ring and the E ring. And these go out like past three to nine times the radius.

of Saturn itself. So like the volume of Saturn is dominated by these rings. It's like the biggest thing in the Saturn system. That's really interesting. So how many rings are there total? Do you know? Well, there are rings out to G rings and E rings, right? And so there are like dozens of these rings. And it depends a little bit on how you count because each of the rings can be subdivided into like sub rings. And some of these rings that have, there are these gaps between them, which are maintained by these little shepherd moons. So you have these little little. little moonlets, which are strong enough to survive inside the Roche limit. Remember, the Roche limit, not a hard and fast rule, depending on what you're made out of.

So if you're a small enough moon and you made out of really tough stuff, then you could survive in the ring system and you sort of perturb the rings. You can keep the rings from like mixing with each other. So a lot of these gaps are because there's a moon there, a little moon lit that's keeping them apart. A little hall monitor moon. That's adorable. Exactly.

And it keeps them having this like really crisply, sharply defined. It seems like there is a bunch of mass in these rings. How do we know that like Saturn's gravity is strong enough to keep them in that sort of sweet spot of staying rings and not drifting out or forming moons? So we didn't know until pretty recently how much mass there was. You know we could see it, but we didn't really know like how much stuff is there. Is it equivalent to a moon? Is it like a thousand times a moon? Is it much less than a moon of Saturn?

And so it was when Cassini went up there and it passed between these rings that it gave us a measurement for how much mass there is. And what we discovered was that the rings had sort of surprisingly low mass. We expected them to have more mass to be like more substantial. But they're really sort of like light and fluffy. The other thing that's really interesting from Cassini is that we got these very close up pictures of what these rings were made out of. And scientists were surprised to see that the components of the rings were still sort of sharp. You know, they have like crisp edges to them. They're really quite reflective compared to what we expected if these rings were ancient.

If they'd been there for a long, long time, you would expect them to bump into each other. Things eventually get rounded. All the radiation from Saturn would have weathered them a little bit. That gives people the impression that maybe these things are quite new, right? If you add up all the mass of these rings, it's just about the mass of a typical moon of Saturn, which is very suggestive. It says maybe this was once a moon of Saturn. Maybe one of the moons of Saturn got smashed up in a collision. They bounced into each other or something came into the solar system and destroyed a moon of Saturn and created this big mess, which then fell into the Roche limit and became the rings of Saturn.

It's a theory. We just don't know, but it's one speculation. So when you're saying these are relatively new, what do you mean by that? Because I've learned that when you say new in terms of the solar system or the universe, it means very old. Exactly. It means new on a universe timescale. So we're talking like maybe in the last 100 million years, whereas the solar system is four and a half billion years old. If you're 45, for example, saying you got a ring in the last year or so makes it feel sort of new. Right. Yeah. I mean, my ring feels still pretty new, even though it's about a year old. But yeah, so that is really interesting. Do you think these rings around Saturn are permanent? Well, we don't know how long they are going to last. If they're fairly new, it suggests that they might not.

They might be like falling into Saturn. Saturn might be losing its moons as its gravity pulls these little bits into it. Or they could also be quite stable, right? Even if they are new, they could still be stable if they ended up in the right spot, if they're within the Roche limit. So in order to understand that, whether Saturn is going to keep its rings, we need to understand some of the processes going on there. Like, is Saturn gathering these things up?

Are things falling into Saturn or not? We also need to understand whether there are new sources for these rings. That same moon we talked about in Salinas also has geysers on it. So like cracks in those oceans shoot water out into space constantly. And this is new material for rings as those newly formed crystals in space get sucked in by Saturn's gravity. So there's a really far out ring called the E-ring, which probably is being constantly replenished by geysers from one of Saturn's moons.

Well, that's interesting. So you've got like a sprinkler system that is keeping these rings alive. Well, I hope Saturn has a sense of commitment. So keeps that ring for our benefit because it is so pretty to look at. But I'm also curious why Saturn is so unique in its rings in the solar system or whether it is unique. But first, I need to take a break and I'm going to do a little hula hooping so I can feel more. like I am Saturn so I can visualize what it's like to be Saturn. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage,

kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing, the TWA terminal. Apparently, the explosion actually impelled metal, glass. The injured were being loaded into ambulances. Just a chaotic, chaotic scene.

In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict, even harder to stop.

Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Oh, wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her.

Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him?

Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytie. podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Hello, Puzzlers. Let's start with a quick puzzle. The answer is Ken Jennings' appearance on The Puzzler with A.J. Jacobs. The question is, what is the most entertaining listening experience in podcast land?

Jeopardy Truthers, who say that you were given all the answers, believe in... I guess they would be Kenspiracy theorists. That's right. Are there Jeopardy Truthers? Are there people who say that it was rigged? Yeah, ever since I was first on, people are like, they gave you the answers, right? And then there's the other ones which are like, they gave you the answers and you still blew it. Don't miss Jeopardy legend Ken Jennings on our special game show week of The Puzzler podcast. The Puzzler is the best place to get your daily word puzzle fix. Listen on the iHeart radio app, Apple Podcasts.

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I'm Jessica Voss. And that's when I was like, I got to go. I don't know how, but that kicked off the pivot of how to make. make the transition. Learn how to get comfortable pivoting because your life is going to be full of them. Every episode gets real about the why behind these changes and gives you the inspiration and maybe the push to make your next pivot. Listen to these women and more on She Pivots now on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. and we're back after an exhausting five minutes of me hula hooping remind me never to do that again

but i was asking before the break is saturn unique in the solar system in terms of its rings and why is it unique because it seems like it at least has the most spectacular rings in the It definitely has the most spectacular rings and the most obvious from Earth. But it turns out it's actually not unique and that there are rings all over the solar system. And there are rings that might be right in our backyard and in our future. When you look up at Mars, which is one of our neighboring planets, you don't see rings on it, but that might be different in about 30 to 50 million years. Because Mars is in the process of pulling apart its moons and shredding them.

them. So they eventually might turn into rings. So physicists out there, I want to give you some advice. If you are in a relationship and you tell your partner, I see a ring in our future, just be forewarned that they may not know you're talking about Mars. And that you've got to wait quite a while. You know, we're talking about tens of millions of years. And Mars is a really fascinating case because it might sort of upend this clear, crisp difference between rings and moons a little bit. I read a recent paper that suggests that it might be in the middle of a ring moon cycle. Then it might be forming moons, which then get shredded into rings,

which then get formed back into moons. So it could be like sloshing back and forth between ringed and mooned and ringed and mooned. That's interesting. I do know some people like that. So how does it, if it keeps shifting back and forth, that must mean that this Roche limit is not always stable. What makes it unstable? Well, it depends, again, on how strong this thing is, the structural integrity of the object

and exactly where it is. The idea here is you have a giant impact, and this giant impact doesn't just create a big spray of debris which can form into rings and moons, but can also actually change the gravitational field of the planet itself. So, like, exactly where the Roche limit is can change. So you can have, for example, the formation of a moon, which can last for a little while, but then as the planet itself settles back down, you know, part of this debris then falls back onto the planet, it can change where the roche limit is. So the moon forms when the roche limits in one

place, but then as the stuff settles in and some of it falls onto the planet, the roche limit shifts. And so the moon can then be torn apart. Some of that stuff might fall down to the planet. Some of it might form a ring. Some of it might form like a half moon, which gets pushed out even further. So we're talking about Mars's potential future here and potential past, but you also mentioned that there are a lot of rings in the solar system currently, right? There are a lot of rings in the solar system, exactly. So Jupiter, for example, also has rings. These are interesting because they're one of the first ones discovered by a satellite. Like, it's very hard to see Jupiter's rings from Earth, even with a very, very powerful telescope.

And so these were discovered in 79 by Voyager 1. And the reason that they're hard to see is that they're very faint and it consists mostly of dust. And people think that they're probably just constantly created by micrometeorites hitting the planet's moons. Remember, Jupiter is very, very massive and is very strong gravity. So it's likely to just like suck a lot of this stuff up. But they think there's like a constant replenishment of this stuff. As things hit the moon, create this like debris, which forms sort of a temporary ring around Jupiter, which eventually falls back into Jupiter. So Jupiter's gravity is so strong that doesn't really have a chance. to accumulate a ring that lasts very long.

You mentioned that it's harder to see it because it's mainly man out of dust. What makes ice more visible? Ice is just shinier, like it's just basic chemistry. You shine a light on a piece of ice. It's going to reflect more than a rock will, right? So ice is just brighter and whiter. I guess that's why we call Diamond's Ice.

That makes sense. And Jupiter also, remember, is not just gravitationally powerful. It has very strong magnetic fields and radiation. And so the electromagnetic forces interact with these, dust particles moving around Jupiter. And it means that it's hard for these things to orbit Jupiter for more than like 100 or 1,000 years. And so for Jupiter to have a ring system at any point that lasts more than, you know, 100 or 1,000 years means it needs a constant source of replenishment. That's why this theory that micrometeorites are creating dust constantly to sort of feed Jupiter's ring

system. I see. So Jupiter's just too hungry to maintain that ring without having some of those micro-collisions spewing out more debris. Is Jupiter the only other planet that has rings? No, Neptune also has rings. These are really fascinating. There are five rings, but they're sort of the reverse of Saturn. Instead of being mostly ice, they're actually mostly dark particles, and they're confined to a few little narrow rings,

and they're really interesting because they're not the same all the way around. It's not like Saturn that has this symmetry. They have these, like, bright arcs and then these empty gaps between them. So it's really kind of weird. So these like broken rings around Saturn? Yeah, exactly. And people think that maybe there are moons there, like little shepherd moons that are interfering with these rings

and causing this structure. But we haven't been able to see them because our telescopes aren't powerful enough yet. And Uranus also has rings. These rings are really strange because they're almost totally black. They're like lumps of coal. So they think they might be like carbon

and hydrocarbon, but they're just not sure. So what we really need are like more, exploration of the outer solar system to understand these rings and the role they play in the history of these planets. I like that Uranus is going for a goth look that is bringing goth back. I don't know if it ever left. So our solar system has a good number of rings, but we talked about at the beginning, whether we are unique as a solar system, whether we can find rings outside of our solar system. Is there any evidence of rings far and wide? So scientists think that it's very plausible that other planets might have rings just because they're not that unusual in our solar system.

As you can hear, they're like basically everywhere. You know, Saturn, Jupiter, Uranus, Neptune, even Mars might eventually have rings. So we suspect that just from that data, they should be in other solar systems. But of course, we want to see it and to know. We don't want to just want to speculate about the nature of the universe. And so what we can do is look for rings around planets in much the same way that we look for the planets themselves. The way we detect planets around other stars, or one way at least, is the transit method. The planet passes in front of its star like a little mini eclipse and dims the light of that star a little bit.

That's how we know the planet is there. How could we see rings around it? Well, from the transit method, we can also get a sense of the size of the planet and its mass. So we get a sense of the size because of how much light is blocked from the star. We get a sense of its mass because we can measure its orbit. And so if the planet seems to be really, really large, there's like this extra reduction in the light of the star because it has like big fluffy things around it, that might be evidence for rings around the planet.

If it seems like bigger than we would otherwise understand it to be, if it seems like bigger than we would otherwise expect it to be from its mass and from its orbit. I see. So if the orbit doesn't match how fluffy it looks, how much light it blocks, that may be a sign of a ring. Could it be something else instead of a ring? Like we mentioned just having a bunch of junk kind of floating around the planet and not ring form? I mean, it could be like a lot of moons, I suppose.

One candidate is this planet HIP 41 378F, which looks like it has a really, really huge radius, like nine times a radius of the Earth. So either it's like a big styrofoam planet hardly filled with anything or it's a planet with an extensive ring system that's blocking all. of that light. And that's really the only thing we can really think of. There's another planet Proxima Centauri, which is a planet orbiting our immediate neighbor, Proxima Centauri. It has seven times the mass of the Earth, but it's sort of weirdly bright and reflective, which makes people think like perhaps it's surrounded by icy rings. But as you can maybe get a sense for, this is very uncertain stuff. We've only just recently been able to detect exoplanets. We're getting better and better at it. And soon we'll be doing things like studying the atmosphere of exoplanets.

This is sort of on that list of things we're just beginning to be able to do. It's kind of like physicists need to start to catch up with jewelers who can look at rings by using a magnifying glass to see things really, really tiny. But physicists have to investigate their rings by looking at things really, really far away and blowing them up as much as they can. Absolutely. And I expect that some of those solar systems may have spectacular ring systems. I suspect that when we get really nice images of them, you know, maybe from James Webb or from the next generation of space telescopes, we'll see things that blow our minds that makes scientists say, what? That's impossible. You can't have rings like that. That breaks all of our understandings. And breaking our understanding is exactly the moment to learn about the universe to say, oh, well, turns out we didn't understand this as well as we thought we did. We got to change our models. We have to add something new to it or develop some new idea for how these things can form.

That's the exciting thing. It's like opening a new book and being surprised by what you find in it. Every one of these solar systems will have surprises for us, things that we probably can't imagine today. And isn't that the dream of every planetary fashionista to wear a ring so spectacular it makes scientists scratch their heads and throw away all their textbooks? Exactly. So from rings down here on Earth, wowing all of your friends to rings around the planets themselves, telling us something about how those planets formed and something about their history and something about their future. Rings have a lot to tell us about the nature of our lives. All right, thanks very much, Katie, for joining us on today's episode about Rings.

It was a lot of fun, and we hope you all ring in a wonderful day. Thank you very much for listening and tune in next time. Bye, thanks for having me. Thanks for listening and remember that Daniel and Jorge Explain the Universe is a production of IHeartRadio. For more podcasts from IHeartRadio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, everything changed. There's been a bombing at the TWA terminal.

Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged. Terrorism. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon.

This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want her gone. Hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast. in the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

Get fired up, y'all. Season 2 of Good Game with Sarah Spain is underway. We just welcomed one of my favorite people, an incomparable soccer icon, Megan Rapino, to the show. And we had a blast. Take a listen. Sue and I were, like, riding the lime bikes the other day. And we're like, we're like, people ride bikes because it's fun. We got more incredible guests like Megan in store, plus news of the day and more.

So make sure you listen to Good Game with Sarah Spain on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Brought to you by Novartis, founding partner of IHeart Women's Sports Network. This is an IHeart podcast.