Daniel and Kelly’s Extraordinary Universe - What's hidden inside planets?

Episode Date: January 16, 2024

Daniel talks to Prof. Sabine Stanley about what's happening inside planets, and how that helps us understand what's out there.See omnystudio.com/listener for privacy information.

This is an I-Heart podcast. December 29th, 1975, 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 or 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 and the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. It's important that we just reassure people that they're not alone and there is help out there. The Good Stuff Podcast Season 2 takes a deep look into One Tribe Foundation, a non-profit fighting suicide in the veteran community. September is National Suicide Prevention Month, so join host, Jay, Jacob and Ashley Schick as they bring you to the front lines of One Tribe's mission. One Tribe, save my life twice. Welcome to Season 2 of the Good Stuff.

Listen to the Good Stuff podcast on the Iheart Radio app, Apple Podcasts, or wherever you get your podcast. Every case that is a cold case that has DNA. Right now in a backlog will be identified in our lifetime. On the new podcast, America's Crime Lab, every case has a story to tell. And the DNA holds the truth. He never thought he was going to get caught. And I just looked at my computer screen. I was just like, ah, gotcha.

This technology is already solving so many cases. Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. When we sit out to understand the universe, we usually start by looking up. After all, that's where the best views. are of the glittery cosmos stretched across billions of miles. We wonder, are we alone? Is there anyone up there looking back at us? But what if the best way to find answers to questions about what's up there is actually to look down under our feet? Hi, I'm Daniel. I'm a particle physicist and a professor at UC Irvine, and I desperately want to know who's out there in the universe, and if they are wondering the same things we are.

And welcome to the podcast, Daniel and Jorge Explain the Universe in which we do just that, wonder about the nature of the universe and try to explain all of it to you. Regular listeners of the podcast know that I am desperate to understand the nature of the universe, how it all works, and to explain. all of that knowledge and all of that confusion to you. One of the deepest questions we wrestle with on the pod is not just about the universe, but kind of about ourselves. How weird are we? Are there more like us out there in the universe? Or are we alone? How rare and special is the Earth anyway? Are we a one of a kind out of a trillion planets? Or are we one of many rocky balls covered in curious life? We're frustratingly limited by what we can learn about distant planets, though we're doing our best, but something we can do right now is drill deeper into our own planet,

understand the forces that shaped it, and whether those are finely balanced in a rare way or naturally in harmony in a way we'll find everywhere in the universe. So today on the podcast, we'll be answering the question. What's Hidden Inside Planets? And to help me explore this fascinating topic, I'm pleased to be speaking to Professor Sabina Stanley, author of a very recent book of that same title. All right, well, then it's my great pleasure to introduce the podcast, Professor Sabina Stanley.

She's the Bloomberg Distinguished Professor of Planetary Physics at Johns Hopkins University, where she focuses on magnetic fields and other geophysical elements as a means of studying the interiors of planets, moons, and asteroids. She's an Alfred P. Sloan Research Fellow and has also received the William Gilbert Award of the American Geophysical Union. Sabina, welcome to the podcast and thank you for coming to talk to us. Thanks so much for having me. So one thing we always wonder about as we look out into the night sky is all the other planets that are out there. Of course, we can't study many of them up close. And so often on this podcast, we've tried to dig in into what's under our feet,

the mysteries that are right here in our Earth. And so I really enjoyed your recent book, What's Hidden Inside Planets. And I'd love to talk to you about what's in our planet. Could you start us off by taking us sort of on a brief tour of like, what is under our feet, layer by layer all the way down to the core? Yeah, absolutely, great question.

So I think it's interesting to note that when you start on the surface, as you go deeper and deeper, stuff gets kind of weirder and weirder and much more different than what we're used to on the surface. So we start on the crust, this is where we live, this is where all the stuff happens that we're used to. Crust can vary in thickness by about five kilometers depth to almost 100 kilometers depth, but under that you get to the mantle. That's also still mostly rocky, the type of rocks that are rich in magnesium and silicate,

but still what we would recognize as rocks. So about half the radius of the earth are those rocks. It goes down about 2,000 miles deep. So what distinguishes then between the crust and the mantle is that like how squeeze they are and how much they flow, or is it a different kind of rock? Great question. Yeah, it's a little bit different kind of rock. So essentially, the crust layer of the earth, I sometimes refer to it as like the scum of the earth. So it's kind of like, you know, like when you're making a soup and you're boiling your broth and you've got all that

light floaty stuff that comes to the top. So the stuff that's the most buoyant when you have certain heat thermal reactions and chemical reactions happening with rocks near the surface, all of that percolates up to the top and that ends up becoming the crust. And then sort of the stuff, underneath might be less scummy, less, you know, it's been less reworked and it's sort of more kind of pristine rock. I see we're going to get started very quickly with the food analogies. Yeah, I'm sorry, it's just going to be how it goes. There's going to be food involved in almost every analogy I make here. Are you a big fan of soup or are you a cook at home? So I'm a terrible cook, but I grew up in a restaurant family. So I've been around sort of good food my

whole life. All right. Well, then let's do our best to at least use tasty food analogies. I don't wanting to think that the earth is like a disgusting bowl of soup. Maybe it's like, you know, bubbling hot cocoa and this is that delicious film that forms on top. I love that so much. You don't even know. So that's amazing. All right. So the crust is the sort of coolest part that floats to the top. And underneath that, it's still rock, but it's able to flow. How do we visualize that? I mean, it's not like liquid lava that's flowing on the surface. This is still like solid rock, but it's flowing. How does solid rock flow is something I've always tried to visualize and failed? Yeah. So the answer to that question is very slowly, right? So, yes, it's solid, but it's still deformable,

right? And I think we have experience with different types of solids in our everyday life, and that some are more deformable than other, right? Like, you might have clay. Clay is solid, but you can still deform it, whereas a metal also is kind of deformable, but then you have some rocks that are really, like a diamond, really hard to deform. But the rocks in the mantle, they are solid, but they can be deformed. And if they can be deformed, then they start being influenced by the forces like gravity such that you can get them to flow. I see. All right.

So we have the crust and we have the mantle, both of which are still really rock. Take us down below that. Right. So then you get down about halfway through the earth and you suddenly hit a very big boundary, complete change of environment. Now you're at the iron core. So the inner half of the planet about, it's mostly made of iron. There's a little bit of nickel mixed in there.

And about 10% of some sort of lighter elements that, We have a whole sort of platter of possibilities for, but we don't actually know what they are. And that makes up the core. The core has two parts to it. The outer port is liquid. It can flow very easily, much faster time scales than the mantle. And it's really important for us because that's where our magnetic field is generated in that liquid iron core. Then below that, the innermost 1300 kilometers of our planet is a solid iron core.

And so what distinguishes then the mantle, which can flow but is a solid, not a liquid, from the outer core, which can flow but is a liquid and not a solid? Like, is there really a distinction here? Are we just putting labels on things? When we study fluid dynamics, we talk a lot about there being a spectrum of fluids, right? Nothing's ever purely a solid or purely a fluid. It's all about the time scales. So the mantle, for example, if you want to talk about how materials flow in the mantle,

a parcel at the bottom of the mantle could take hundreds of millions of years to make it to the top of the mantle, whereas a parcel at the bottom of the core could take, a couple of years to get the top of the core. So it's a very different time skill of the flow. You could actually see changes in material in the core flowing. But there's also like a boundary. It's not like there's a smooth, very gradual transition. There's like a line you can say, this is the core and this is the mantle. Yeah, and that happens because mantle rocks and iron in the core have very different densities. And at one time in the past, in our planet, it was mostly molten and so the heaviest stuff when you when you have a bunch of stuff mixed together the

heaviest stuff's going to sink to the bottom and so that's what happened in earth the all the iron most of the iron sunk to the center of the earth and made up the core like the big chunks in a stew or something exactly yes i like it so the reason that there's a boundary there and like a transition and rather than just like a smooth gradation for more liquid to less liquid that reflects like the phase transitions and materials is that right the way that like ice turns solid at some moment and doesn't just, like, gradually become more and more solid. I would say that's more representative of what kind of happens at the inner core, outer core boundary, so where the iron becomes solid.

But above that, it's more kind of like a maybe you go with an oil and water type thing. You've got two materials with very different density and very different properties, so it's really hard to mix them. Wonderful. And tell us about how we know about this. I was reading in your book this really exciting description of the mantle race, basically like a parallel to the space race, but into the earth.

Tell us about our humanity's efforts to literally tunnel to the center of the earth. Yeah. So if you imagine you want to figure out what's inside the earth, right? Your first instinct might be, hey, why don't we dig down as far as we can and actually sample it, right?

And it's a great instinct. Unfortunately, it's incredibly challenging to do. And that's because pressure increases so fast as you go deeper inside the planet and so do temperatures. So as you can imagine, humans don't like really high pressures and temperatures.

Neither does equipment. and the farthest we've been able to dig with a sort of a really concerted effort to do so, right? Like this was something on the scale of moonshot to the moon in the late 60s. This is something very similar to that and you could get only down to about eight miles in depth. And the radius of the earth,

you're talking about 4,000 miles. So tiny, tiny scrape of the surface by going down that deep. Equipment does not like high pressures and temperatures. But how do you even get eight miles deep? I mean, I do remember digging in my backyard with a shovel wondering how far I could get and it was not very far.

How do you get eight miles down? This is like high-tech technology kind of stuff. It's at the limits of what we can do for drilling that we do now to drill for resources, et cetera. So it's a lot of fancy equipment and challenges that are overmet that way. So we can't dig and we can't drill. But that's okay because there are other ways we can figure out what's going on deeper inside the earth.

Yeah, so tell us about some of those ways. You were talking in the book about diamonds, how we can use diamonds to give us little snapshots of what's inside the planet. Yeah. So, you know, it would be great if we could dig down. But would it also be great if the stuff down there came to us. And that's really what happens with diamonds. Diamonds are produced deeper inside the earth.

And then they come up to the surface, usually in volcanic vent, things known as Kimberlite pipes. And those diamonds, you know, jewelers love diamonds when they're as pure as possible. Geologists love diamonds when they're as impure as possible. So sometimes diamonds, when they form, they can enclose, a little capsule of some of the material where they formed inside them, right? So you might get a little bit of garnet in the diamond or a little bit of something that was created deeper in the earth. And when it brings it up because diamond's so strong, it actually keeps the

material in its like pristine form. So you really have this like sample from the interior of the earth come to the surface for us to investigate. So that's a great way. And we've used that, for example, to figure out that there is actually water deeper inside the earth because we've found water inside diamond inclusions. It's fascinating to me, though, that this thing that you make in a high-pressure environment, when you bring it up to low pressure, it doesn't explode. Is that just because of the incredible structure of diamond? Yeah.

When they say diamonds are forever, that's technically not true, right? They just have a really, really long lifetime before they revert back to their carbon phase. So, yeah, it's just a great property of diamond. So is it sort of like, you know, you put a pan of brownies in the oven, and it changes into something else, and when you take it out, cool it down, it doesn't revert back into batter. That's an excellent way of thinking about it. Okay. And so then what have we learned from these diamond samples?

Like what's inside these diamonds that we didn't realize other than water? Yeah, I think water is the big thing. Sometimes it's a lot about sort of the smaller amounts of elements that we don't know about, right? How much of a particular kind of is silicon down there, is sulfur down there, these kinds of questions. And those all just help us understand what the building blocks of Earth were when Earth formed. and what the geochemistry, the kind of chemical reactions that can occur as material descends into the earth, that's really where we get that information. But even with diamonds, right, we're talking about the outermost layers of the mantle, right?

Diamonds, we don't get diamonds, say, from the core mantle boundary or anywhere deeper than that. So we can't use the diamonds to learn about the deeper parts. Is that because diamonds aren't made deeper or because diamonds from that far down just don't make it up to the surface? Mostly the latter, I think also, like if you get carbon down there, yeah, it doesn't necessarily. necessarily join into making diamond at that depth. All right. So there aren't like huge diamonds buried deep in the earth that we are unable to access.

Not on Earth, no. Not on Earth. Well, that was my whole motivation for digging so deeply when I was a kid, fantasizing about revealing some, you know, boulder-sized diamond. All right, so diamonds give us one sample. What else can we do? What about gravity? What about just studying, like, the variation in Earth's gravity as we, you know,

orbit the planet or look around it? What does that tell us about what's inside the Earth? like to think about it is, you know, if you want to figure out what's going on inside the Earth, try and make an analogy to a human body, right? If you have an ache and you go to your doctor and you're like, this hurts, hopefully they're not, their first kind of instinct is not to drill a hole in you to figure that out, right? There are ways that they can use different fields and different scans to figure out what's wrong with your insides. And we can do the same thing for the inside of the earth. So we can scan gravity, as you mentioned. That's one. Magnetic fields is another one.

And we can also determine properties of waves that travel through the Earth from earthquakes through seismology. So we can use all these scanning techniques to figure out what's going on deeper inside the earth. So what do you mean by using gravity? Is it just like measuring the variations of gravity so that we understand how the Earth is not a perfect sphere or how the Earth is not homogenous in density? What is it we're learning? Yeah, great question. So, yeah, it really is the fact that both isn't a perfect sphere and has some in homogeneous material below it, right? So if you were walking around with a gravimiter that could measure gravity and it was really, really good.

And you walked around, you would get slightly different values everywhere you walk. And that would be determined by the mass directly under your feet. And so we can use that information. We have spacecraft that orbit the Earth that measure Earth's gravity field to really high precision. And we can use that to figure out what is the distribution of density inside the Earth. And that kind of allows us to kind of image what's going on. Where is the denser stuff in the Earth? Where is the lighter stuff?

And we can actually see things like convection cells in the mantle and plumes of magma coming up for volcanoes, things like this. But gravity is such a weak force. How do you identify these variations in density with such an incredibly weak force? They must be pretty big effects. They aren't. They are very, very tiny effect. We're just really good at measuring them. So a gravimiter, you mentioned, this might seem like a weird object or listeners.

But I guess like my bathroom scale is a gravimiter. If I walked around the earth with my bathroom scale, I would make. measure different weights before and after lunch, of course, but also if I didn't eat anything or I used a reference mass, then I guess I would measure different accelerations due to gravity. Yeah, absolutely. And if you were someone on the surface taking gravity measurements, that's exactly the kind of instrument you would use. Interestingly, once we get into orbiting around a planet like Earth, to take measurements, we use a completely different technique. We basically use the fact that if we have a spacecraft in orbit around the Earth, we know it's in orbit around

the Earth, and its orbital speed and altitude is completely determined by the mass of the planet. So we can use things like two spacecraft, just slightly at different locations from each other, kind of moving around, and we can use the distance between the two spacecraft as like a proxy for how much G is right where they are, how much the gravity is right where they are. So that's actually how it's done in practice with spacecraft? Wow, that's incredible. And how sensitive are they? I mean, like one part in a thousand, one part in a million? Yeah, one part in a million. That's where we're getting to. Wow. So they can really tell if I've eaten lunch, some spacecraft up there can tell that the mass of the Earth has changed. One thing they're actually used for, so the gray satellites,

which orbited Earth for about 10 years, one of their main applications was to follow water flow on the surface. So you could see, for example, when water was filling reservoirs, underground reservoirs in certain parts of the country or different countries, if you wanted to see, are we going to have a drought? Are we in a rainstorm season? What's the water situation going on here? So we can even use gravity to attract climate change. Wow, that sounds like modern day divining rods, but you're actually using science to find the water underground. That's incredible. All right, so gravity is one way to do it. You also mentioned seismic probes. These are like waves inside the earth. How do we use that to see what's going on? So every time there's an earthquake, it's like sort of something

kind of punched the inside of the earth at some point, and it causes the earth to ring. It causes waves to travel through the interior of the earth. And on the surface of the earth, if we put out a bunch of instruments that can kind of measure the shaking, so seismographs, then we can figure out a few things about the earthquake waves. We can figure out when they arrive at different locations around the planet and how big the waves are, the amplitude of the waves. And the speed, the timing of when the waves arrive, is completely directly related to the material properties that the waves traveled through. So, for example, we can figure out the density of material that a wave traveled, say, from, let's say, an earthquake happens in California, and the wave

travels up to Seattle in Washington, you can use that to figure out kind of what's the material just under the surface there. Whereas if you try to go across the globe to another part on the other side, the waves might travel through the entire planet. And we could actually sample the material in the core, for example. So you can use all those different measurements. The more locations you have on the Earth for these seismic measurements to be made, the more you can kind of discern what is the lateral structure of the interior of the Earth. And we're really talking about sound waves, right? These are pressure waves in the rock. And so we can think about how denser materials have sound travel faster and less dense materials, sound travels lower. So you're

measuring the density of the material by measuring the speed of sound. But again, these are rocks that are like pushing on each other, right? Like sound waves through rock is a very weird thing to think about. Yeah, absolutely. So there are the sound waves. The other type of wave that goes through are these shear waves. So those are kind of more like waves you'd experience in a fluid, let's say, or not in a fluid, sorry, waves that you would experience if you try to kind of bend peanut butter or something like that, right? So there's multiple kinds of waves and some of them are very diagnostic of what's going on in certain types of materials. Well, I never thought we'd be talking about peanut butter waves, but here we are. So when did we get this picture? Like, what is the first

technique that really gave us a view of the inside of the earth? Was it the seismographs or is it something else? That's a good question. It's not like there was a sudden moment where suddenly we had this picture of the earth. I think we developed our understanding to higher and higher precision as time went on, right? I think early studies of gravity, going back to Newton, let's say, was able to tell us this is the mass of the earth. And then you could take, for example, samples of crustal rocks and figure out what their density was and infer, hey, there must be a lot more mass deeper in the center. So that was kind of first order information you might get. So through both seismology, so early 1900s was when we were doing some really great seismology figuring out things like, oh, look,

we have a core, right? That was where the core was first discovered, the inner core was discovered in the early 1900s. The first sort of real profile of density through the Earth happened, I think it was in the 70s with what was called the preliminary reference Earth model, which really used a whole bunch of seismic data to really kind of do an inverse problem and figure out, here's what the seismic wave speed and the density has to be at every depth in sort of like a 1D Earth. So that was a big step forward there, too. But at the same time, gravity was being used. And so we were getting pictures from different types of information. But it's really only a few hundred years that we've had any sort of reasonable idea of what's under our feet. And it sounds

like only the last few decades, maybe 50 years, that we've had any sort of detailed picture of what's actually inside our own planet. It's incredible how long we can remain ignorant about really basic science about our own lives. Yeah. When I talk to people, I kind of, I tell them geophysics is really modern physics, because all of the stuff we're doing now is all stuff that's happened sort of in the last 60, 70 years. So I like to think of it as a modern physics approach. Right. And now we've extended this frontier to other planets. We've talked in the podcast before about the Insight Mission, and I think you worked on that, measuring Marsquakes to see what's inside Mars. Did the same principles apply there? Yes, absolutely. So the amazing thing with the

insight mission is brought a seismometer, and that seismometer had to be placed onto the the surface of Mars so that it could measure the ground shaking, essentially, and it worked, like it was just amazing that it worked. But it was a very interesting experience because for most of the mission, and especially in the beginning, all the Marsquakes we were seeing were quite weak. We were looking for the big one, right? We were looking for the big Mars quake because the bigger the quake, the more waves will travel through the deeper parts of Mars. And so we really wanted to study, or I really wanted to study the core. And for that, we needed some big Marsquakes and they really didn't happen for the first few years. And then right near when the

mission was about to end, we suddenly had a few. So that was really amazing to get that data at the end. So Mars kind of kept us hoping for a while and then finally delivered. And before you landed on Mars with this seismometer, did you have much reason to expect that there were Marsquakes? Or it could be that Mars was totally silent? I mean, it could have been, we didn't have any direct evidence for Marsquakes, but my geologist friends who are used to looking at, say, tectonic features on the surface, looking at things like, where are the cracks in the surface, where are the mountains, they would have told me to expect Marsquakes because they see movements. Geologically, they see movements on the surface.

But also, luckily, we kind of have our own source of Marsquakes in a way. When meteors hit planets, they crash into them, they're kind of like a hammer that's smashing into a bell, right? And so a lot of the Marsquakes we measured were actually caused by meteors that hit Mars, as opposed to just tectonic activity happening in the interior. Well, it's terrifying to me or feel a little conflicted. the geologists are rooting for quakes and rooting for, like, big impacts because they're like, ooh, yay, data.

Yes, exactly. I will, I mean, as a funny story on the mission, we did at one point. So the Insight mission was on the surface when the Perseverance rover was planning to land. And we did kind of do a calculation where if the landing didn't go so well, would we be able to detect the wave from that? Luckily, that didn't happen. We had a very nice landing. Yeah, congratulations on your landing.

Too bad we didn't get some cool data, though, from your explosion of your huge project. Oh, my gosh. All right, this is really fun, and I want to hear a lot more about what's going on inside our planet. But first, let's take a quick break. December 29, 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 is 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.

Well, 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 Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast.

Hey, sis, what if I could promise you you never had to listen to a condescending finance, bro? Tell you how to manage your money again. Welcome to Brown ambition. This is the hard part when you pay down those credit cards. If you haven't gotten to the bottom of why you were racking up credit or turning to credit cards, you may just recreate. the same problem a year from now when you do feel like you are bleeding from these high interest rates i would start shopping for a debt consolidation loan starting with your local credit union shopping around online looking for some online lenders because they tend to have fewer fees and be

more affordable listen i am not here to judge it is so expensive in these streets i 100% can see how in just a few months you can have this much credit card debt and it weighs on you it's really easy to just like stick your head in the sand it's nice and dark in the same sand. Even if it's scary, it's not going to go away just because you're avoiding it. And in fact, it may get even worse. For more judgment-free money advice, listen to Brown Ambition on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. A foot washed up a shoe with some bones in it. They had no idea who it was. Most everything was burned up pretty good from the fire that not a whole lot was salvageable. These are the coldest of cold cases, but everything is about to change.

Every case that is a cold case that has DNA right now in a backlog will be identified in our lifetime. A small lab in Texas is cracking the code on DNA. Using new scientific tools, they're finding clues in evidence so tiny you might just miss it. He never thought he was going to get caught, and I just looked at my computer screen. I was just like, ah, gotcha. On America's Crime Lab, we'll learn about victims and survivors, and you'll meet the team behind the scenes at Othrum. the Houston Lab that takes on the most hopeless cases to finally solve the unsolvable.

Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Okay, we're back. We're talking to Professor Sabina Stanley, author of the book, What's Hidden Inside Planets, about what's Inside Our

planet. You mentioned earlier that it was amazing that Insight worked. Is that just because it's hard to land stuff on Mars and operate a robot on another planet? Or was there something particularly challenging about a seismometer on another planet? Yeah, Insight had a lot of firsts, I would say, right? It wasn't the first lander. We've had other landers on the surface, but this was the first time we were going to take equipment that was stored on top of the lander and actually physically move it to put it on the surface. So there were lots of ways that could have gone wrong, right? This lander had this arm-type device that had to pick up the seismometer on the lander and move it onto the surface. So that required tons of work to get that to just work properly.

Then it had to put a windshield on top of the seismometer to make sure that we didn't measure a bunch of wind, basically, because wind also shakes seismometers. Then the seismometer wasn't the only instrument on insight. There was also a thermal probe, what we called the mole, which was supposed to dig down about 10 meters and take temperature measurements at depth, which would have told us about the heat flow coming out of Mars. Again, this was going to be the first time anything like this was tried, and unfortunately we couldn't get the mold to dig deeper than about tens of centimeters. The properties of the soil, soils kind of a word we use, but the properties of the sand on

Mars were not as we expected, and just the device couldn't actually use friction to dig down deeper and deeper. So that was a struggle. And we actually, the insight engineering team that worked on this and the scientists that worked on this, you know, I wasn't part of this. It was just amazing the things that they tried. And in the end, we actually did get some good science out of it. We measured more sort of the thermal properties of the upper part of the crust as opposed to deeper down. But it was just amazing to see how much they tried to work on doing this first digging on here. You know, we talk about digging on the earth is hard. Now imagine digging on another planet without humans. And it's even harder. Wonderful. And then what are the plans for the future? Is NASA planning to dig into the surfaces of any other objects in the solar system or put seismometers on any other surfaces?

So I think seismometers is definitely something that's going to go. So there is a big push right now to send spacecraft back to the moon so that we can better understand our closest celestial body, let's say. And so there is a mission that will involve putting a seismometer, putting more seismometers on the moon. We already have some seismometers on the moon that were turned off a while ago. for budgetary reasons, right? So it'll be great to get seismology again on the moon. But for me, the most exciting is that an upcoming mission that's planned to go to Titan, which is a moon of Saturn, is actually going to have a seismometer on it as well. So it'll be interesting to see what we can learn about the interior of Titan. And what do we know right now about the interior of Titan? And how could we know anything about it just from like looking at a few photons that

happened to reflect off of it? So Titan is one of my favorite places. So it's really exciting to think about what they're going to see. So Titan's a unique place. First of all, it's the only other planetary body in the solar system that has a nitrogen-based atmosphere that's thick, like the Earth's. So Earth's atmosphere is mostly nitrogen. And the surface pressure on Titan is about one and a half bars,

so one and a half Earth atmospheres. But the cool thing about Titan is that it's a small planet, and so it has very little mass, and so its gravity is really low. So if you were to go to Titan and put some cardboard on your arms and flat them, you would be able to fly on Titan because you have ideal buoyance. situation there. You've got thick atmosphere, low gravity. So it's really easy to fly there. So in contrast, like they had the helicopter on Mars, that was a real challenge because the atmosphere was thin and a helicopter needs atmosphere. Exactly. Exactly. So the Dragonfly mission,

which is going to tighten, should get there in the mid-2030s, it is going to involve a dual quadcopter. So this thing has basically eight rotors. And this, to me, because I'm Canadian, it looks like a skidoo or a snowmobile because it has these sled tracks underneath it. But it's basically going to fly around, land somewhere, do a bunch of science, then take off again, look for a new location, scout somewhat, then fly to a new location, land again. And so it's going to be able to do local science, right, at an individual location for a bunch of locations over the surface. And that's really the challenge in planetary science is this kind of combination of get lots of data from lots of different places, really locally, really close to the surface.

So that's going to be a very exciting mission. We'd have to ask you about that. Is that going to be self-directed? Is it going to decide on its own where to go? Or is it going to wait for signals for minutes and minutes from Earth? Full disclosure here. I have no involvement in the Dragonfly mission. I'm just a super fan.

But my understanding is what it's going to do is when it kind of goes up to the one time, when it flies up one time, it's going to survey, it's going to look around. Then it'll come back down, recharge its batteries. And during that time, when the data gets back to Earth, people are going to look around and say, let's go here, right? That place over there looks kind of interesting. So it'll be a combination. Some of the in-time flight stuff is going to have to be done by the spacecraft by itself.

But when it comes to making decisions about where to go next in terms of big steps, that's going to be done by the people back here on Earth. I really liked your comment about needing to sample several places. It seems obvious that if you only land on Earth in one place, you might conclude, oh, this whole place is granite or, oh, look, it's all beautiful marble or something. Obviously, you need to look around to get a better sample. And so when we only land on one place on the moon, like the Apollo astronauts, you know, only looked or near where they landed, we may have gotten a biased sample of what's going on up there.

So that's really cool that they're going to explore it. So other than landing on the surface, in your book you were talking about seeing what's inside a planet by basically how it wobbles. Can you walk us through the physics of that, the moment of inertia and how it gives us a picture of what's inside? Yeah, absolutely. So all of the planets spin to some amount, right? That's why we have a day on the Earth. And when it spins, a planet doesn't just stay a perfect sphere. It kind of gets fatter at the equator than it does at the poles.

Now, it turns out that how fat it gets at the equator versus the poles is directly related to what the material properties of the object are. So, for example, if you had a perfect water planet, right, imagine the small planet made a water and you spun it. There's a specific, like, ellipsoidal shape you would get for a liquid planet. Whereas if you had a dense core inside the planet with a solid layer and then a water ocean on the outside, you're going to get a different amount of flattening or a different amount of kind of bulging at the equator from that. So we can actually use the amount of bulging of these planets when they're spinning to get information about what's inside.

So for example, you spin a basketball, it stays a sphere. But if you spin a blob of pizza dough, it becomes a disc, right? And so it tells you pizza dough softer than basketballs, I guess. we already knew that, but you're saying we can apply the same thing to planets. By the deformation of the sphere, we can tell basically how rigid it is. Yes, absolutely. And also where the dense, how dense it is essentially in different parts. So for example, Saturn, right? Saturn is the bulgiest of all the planets in our solar systems. Even if you look at through a telescope, it doesn't look like a sphere. It actually looks like more of an oblate spheroids. So it's really interesting

to look at Saturn through a telescope. You mean Saturn looks like squished like somebody sat on it? Yes, Saturn looks like someone sat on it. in the best possible way. I mean, Saturn's beautiful. Yes. Yes, absolutely. But because of that, we know that Saturn isn't just a ball of hydrogen and helium. We know that there have to be some rocks inside, kind of condensed at the center, and then the gas sphere is kind of more on the outside of it. So we've actually been able to figure that out from the size of its equatorial bulge. So that's the first way we can use rotation. There are other ways. So for example, as planets orbit and rotate, they can actually, as they're rotating, they don't always point their North Pole

to exactly the same location so they can actually process. So their rotational axis can move around in a circle about their orbit axis. And if you've ever played with like a top, like a toy top and you've spun it and you've seen it make this little wobbly circular pattern, planets do the same thing. So planetary rotation axes wobble. They process and they also do this thing called mutating where they kind of dip down a little bit. And the period of those procession motions and so kind of how cyclical they are really tells us about the interior properties as well. But why does it happen in the first place? I mean, does an angular momentum tell us that it should we spin along the same axis?

Is this the effect of like other things pulling on it? Yes, exactly. So if Earth were alone, if it was just the earth and nothing else was around, we would not have any procession or mutation. But we've got the sun, we've got the moon nearby, and both of those things cause processional motions and wobbling mutational motions that affect our orbit and our day. So Jupiter and the other things are pulling on the Earth

and changing the direction of its spin axis, basically, like where the North Pole is pointing in the galaxy. And you're saying that tells us something about what's inside the Earth. People, I think, are used to thinking about the gravitational model of like, well, you can treat the whole planet as a point mass at its center of mass. I mean, you can't learn anything else about it. So how is it possible to know something

about the distribution of mass inside the planet from how its spin wobbles? So the wobbling and the spin can tell you things, for example, like if you have a liquid layer inside the planet. So I don't know if you've ever played this game, but if you take a beach ball and you put like a little pocket of water in it and you try to throw it to someone, it moves completely differently than if you don't. Or even easier, take an egg, take a raw egg and take a cooked egg, both still in their shells, and put them on your counter and spin them. And you will see that they spin very differently because one of them has liquids inside of it and the other one is fully solid. So we can use the way that the spin axis wobbles to figure out, are there liquid layers in this planet? Is it fully solid?

That sort of thing. I see. Is this planet more like a soft or hard-boiled egg? That's incredible. And can you also measure the moment of inertia of the planet and tell like where the mass is distributed? Like you can tell the difference between like all the mass being at the core versus all the mass being at the surface. Yeah. So it's a bit complicated in the math, but it turns out that the procession rate, so how well,

fast the axis of the rotation processes about the orbit normal. I'll give you an example. So on the Earth, right now our North Pole points to the North Star. It was named that way for a very specific reason. But it's moving around. And it takes about 26,000 years for that pole to get back to the North Star, right? So the period of our orbit is 26,000 years. And that period can be used to actually determine the moment of inertia of the Earth through some fancy math formula. is. And so if we can measure the procession rate or the period for other planetary bodies, we can also figure out their moment of inertia. Wow, 26,000 years. How long have we been making these measurements? Couldn't have been more than a thousand years at maximum? Yeah, yeah. It's

definitely less than that. But you know, you can trace out a little arc of a circle, then you can pretty much draw out the rest of the circle. Yeah, I guess we have a model and we can fit to that little arc. That's amazing, incredible. We can learn so much about what's inside these objects without even ever going inside. All right, I can't wait to talk about this some more, but first we have to take another 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. 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.

he 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. Hola, it's Honey German, and my podcast, Grasas Come Again, is back. This season, we're going even deeper into the world of music and entertainment, with raw and honest conversations with some of your favorite Latin artists and celebrities. You didn't have to audition? No, I didn't audition. I haven't audition in, like, over 25 years. Oh, wow.

That's a real G-talk right there. Oh, yeah. We've got some of the biggest actors, musicians, content. content creators and culture shifters sharing their real stories of failure and success. You were destined to be a start. We talk all about what's viral and trending with a little bit of chisement, a lot of laughs,

and those amazing vivas you've come to expect. And of course, we'll explore deeper topics dealing with identity, struggles, and all the issues affecting our Latin community. You feel like you get a little whitewash because you have to do the code switching? I won't say whitewash because at the end of the day, on me, but the whole

pretending and cold, you know, it takes a toll on you. Listen to the new season of Grasasas Come Again as part of My Cultura Podcast Network on the IHartRadio app, Apple Podcasts, or wherever you get your podcast. A foot washed up a shoe with some bones in it. They had no idea who it was. Most everything was

burned up pretty good from the fire that not a whole lot was salvageable. These are the coldest of cold cases, but everything is about to change. Every case that is a cold case that has DNA right now in a backlog will be identified in our lifetime. A small lab in Texas is cracking the code on DNA. Using new scientific tools, they're finding clues in evidence so tiny you might just miss it.

He never thought he was going to get caught, and I just looked at my computer screen. I was just like, ah, gotcha. On America's Crime Lab, we'll learn about victims and survivors, and you'll meet the team behind the scenes at Authrum, the Houston lab that takes on the most hopeless cases to finally solve the unsolvable. Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Okay, we're back and we're talking to Professor Sabina Stanley, author of the new book, What's Hidden Inside Planets, about what's inside the Earth, and other planets.

Now I wanna talk about sort of how the inside affects the outside because obviously if you're just curious about how the solar system is formed, you wanna know like what's inside the Earth. But even if you're not, like it has an effect on living on the surface, right? Tell us about like how the magnetic field of these things is generated

and how it relates to bubbling soup. Yeah, so magnetic fields are my favorite topic, not gonna lie. So here's this amazing thing, right? We're on the surface of the earth and one of the reasons it's such a nice place live at the moment is because we have this beautiful magnetic field that completely envelops the Earth. And that magnetic field, what it does for us is it shields the surface from high energy particles that come from the solar wind, which come from the sun, and from cosmic rays that come

from deep space. And those very high energy particles, if we didn't have our magnetic field, they would kind of blast the surface of the Earth, and they would do some terrible things. First of all, they would cause high radiation environments, so we'd likely have higher rates of cancer, for example. but also they cause lots of electrical disturbances. And if you think about our power grid, our power grid does not like there to be large fluctuations in electromagnetic fields. That's another thing that is not so good.

It also tends to these solar winds that bombard planets, they can actually erode the atmosphere of a planet. So they can basically, you know, it's like pointing a hair dryer at the Earth. You're going to be able to blow off all the gas from it. So there are all these things that the magnetic field actually shields us from. But this magnetic field that surrounds us is actually created deep inside the earth in the iron core.

So iron is a great electrical conductor. When you have a great electrical conductor, if you can get it moving around in the right way, then you can actually generate magnetic fields. And the best kind of analogy I can think of for this is if anyone has a home generator or if they have a bike light that they can pedal to get going, you're basically converting the kinetic energy of that motion into electromagnetic energy. So you either, you know, your pedaling causes your bike light, causes currents to flow, that causes your bike light to shine, right? Or it's similar in your generator.

So in the core of the earth, convection, which occurs because the center is hotter than the outer parts of the core. So you kind of have bubbling up like you would if you put a pot of soup on the stove, right? You get the bottom of the pot is hot, the top of the pot is cold, so you get these overturning motions in the soup. Same thing happens in the core. and so that overturning motions, they create magnetic fields, and you get what's called a dynamo. So the dynamo in the center of the earth generates this magnetic field that protects us on the surface. Amazing.

And so you're saying that it's the convection cells that generate the magnetic field, not, for example, the spinning of the planet. Right. So there's a somewhat common misunderstanding out there that the reason that Earth has a magnetic field, for example, is due to its spinning. And this has been used sometimes, for example, to explain why. Venus, which is spinning very slowly, doesn't have a magnetic field. And it turns out that you don't need spinning at all to generate a magnetic field. So magnetic fields can be generated through dynamo

processes without spinning. Now spinning sometimes helps in organizing motions and stuff like that, but it's not actually a requirement. So it's the convective motions, not the spinning. Right. And so in your analogy, you're talking about like peddling your bicycle to generate electricity. And we haven't seen any magnetic monopoles in our universe. So we know that to generate magnetic fields, you have to take a charge and put it in motion, which is how electrical generators work. But what is the charge here? Like we have flows of iron. Iron is obviously metallic and it conducts, but don't you need some ion in motion in order to get a current going? What generates the actual current? If you just have neutral iron, how does that generate a magnetic

field? Yeah, it's actually an induction process. So what it is is you've got a good electrical conductor. And imagine you have a magnetic field and it's frozen into a good electrical conductor. So magnetic fields tend to stick inside good conductors. They don't like to change. But imagine then that you start moving that conductor around relative to itself. So you shear it, you pull it apart a little bit. That magnetic field has to go with it. So you stretch and twist the magnetic fields through the motion itself to create new magnetic fields. Wow, fascinating. And the Earth's magnetic field, though it's pretty reliable, is not actually constant. Isn't it gradually changing? Yes, absolutely. So we have records from the rocks in our crust.

they can be magnetized at the time that they form. And those records tell us that Earth's magnetic field has changed over time. We at least have data that shows it's been around for about 3 billion years, if not longer. But it hasn't always been the same. So there are times in the past where the field has gotten weaker. There are times in the past where the field has flipped polarities. So the north magnetic pole became the south magnetic pole and vice versa. And even today on like weekly time scales, we can measure the small changes in the Earth magnetic field.

that are happening from a variety of things. Some things are external, but sometimes we can also see on a yearly scale, we can see the changes due to different flows happening in the core of the earth. Can we use these changes in the magnetic field to sort of image those flows the same way we can see changes in the gravitational field to give us a picture of what's inside the earth? Yeah, it gets a little more challenging, the deeper you go. And with magnetic fields, what we can see, for example, is because we know it's a good electrical conductor, if we see a magnetic field pattern drifting in one direction, so for

example, there's this kind of famous thing we talk about in geomagnetism called the westward drift. So if you follow certain features of the magnetic field, you see they all kind of drift westward. And we interpret that to being there's flow generally in the westward direction. There's like a jet stream in the core of the earth that's flowing westward that's taking the magnetic field with us. Wow. And so how well do we understand this process? Are there still open questions about like why it's flipping and why it's changing? Or is it something that we understand pretty well. So many open questions. So the amazing thing about this process, so fluid dynamics, if you've had any experience with climate modeling or trying to study flows

that happen in pipes and so forth, fluids are really complicated. They can display turbulence, for example, or laminar flows depending on what types of, you know, what the situation is like. Now, if you add to that, add to fluid dynamics magnetic fields and all the things that happen with magnetic fields, you almost get an added complication. And so when we try to think about, well, how do we study the dynamo process, right? We can't really wait thousands of years to watch the real system over time. We want to study it faster. So you can either do experiments, or you can try to write a computer model that can mimic what's going on in a core when it's generating a magnetic field. Experiments are really hard. Turns out that dynamos, they like three things.

They like really good electrical conductors. They like really fast motion. and they're like really large-length scales. And then you start saying, okay, I'm going to build my giant sphere of a really good electrical conductor and then spin it really fast, and you end up with a huge challenging problem. The biggest dynamo experiment out there is the three-meter dynamosphere in Maryland,

and it has yet to generate an active dynamo. So that's a challenging problem. We use computer simulations to study dynamos inside planets. The problem there is that planets, the motions, the scales, and the motions are so tiny and so fast that there isn't enough computer power on the planet to run a simulation accurately. So we have to make a lot of assumptions and simplifying type conditions. So we aren't able to fully study the system the way we want to. We have to be very

nuanced in how we study it. Well, do we understand why the Earth's flipping of the magnetic field seems so irregular compared to, for example, the sun, which has this rock solid solar cycle of 11 years? Yeah, we don't fully understand why at all. We can't even kind of predict what we would expect for other planets as well. We have what I would call a hand wavy understanding in that we would describe the core fluid as being a very nonlinear system that can have different attractors or different stable systems. And sometimes it's in one stable position, sometimes it's another. And so if you have something near a stable position, imagine you have a ball sitting and you have like a nice valley and two hills on the side and you stick the ball on one of the tops of the

hills, right? It'll pretty much stay there. But maybe if you shake it a little bit too much, a bit too many perturbations, it'll sink down and go to the other stable position. So we think that some perturbations in the fluid can sometimes cause the field to flip, but we don't have a good way to, for example, predict when the next flip is going to happen. What's the key factor that causes such a flip, for example? And these are all areas of current research. Wow. And then as we discover planets in other solar systems, how do we begin to do geology of those planets?

And first, I guess, this is a trivial question is, would you call it geology? Geology is to study the Earth. So is this like exoplanetology? What do you call it? This is a great question. I think the norm has been to refer to geology as looking at rocks and it doesn't matter where those rocks are. So rocks, there are Mars geologists. So I'll just put that out there instead of Marsologists or whatever you would call them instead. Yeah, with exoplanets, the challenge there is the type of information you can get can be quite limited compared to what we can get when we're in our own solar system or here on the Earth. But even with the standard techniques that can discover exoplanets, right?

If you think about the methods involving radial velocity detection, so where you measure fluctuations in the star's light curve caused by the motion of a planet around it, you get information about the period of the orbit, and that can also give you measurements about the mass of the planet. Then if you use transit where a planet passes in front of or behind a star, you can get information about the size of the planet. So as soon as you have the size and the mass,

you already have kind of an average density, a bulk density of the planet. So we have sense of whether, when we discover these exoplanets, is it a gas giant? Is it an Earth-like planet? Is it an ice world like Uranus and Neptune? So we can do some very broad geology, let's say, from that type of information. But what I'm most excited about is the possibilities that are going to come forward with JWST. because this new telescope is going to be able to measure the atmospheres of exoplanets and tell us what they're made of, that's going to be crucial information

to figure out what's actually going on deeper inside the planet, right? Our atmosphere on Earth is the way it is because of interactions with the interior of the Earth. And so we're going to be able to use information about the atmospheres of these exoplanets to also tell us something about the interior. What do you mean by that? I know our atmosphere is different because we have a magnetic field and because of the surface gravity, what else does our atmosphere tell us about what's inside the Earth?

Right. So if there was an alien flying by our solar system and all it could measure is kind of the spectrum of our atmosphere, it would be able to tell that there was life here, most likely, right? We've done things to our environment to make it very obvious that there is industrial action happening on the surface, right? But also, for example, a lot of the processes that regulate some of the key species in our atmospheres, like carbon dioxide,

On Earth, there's the carbon cycle. The carbon cycle not only involves the atmosphere, it involves the ocean, the surface, and the deep interior. So carbon gets recycled inside the earth. And so we can actually learn about how exchanges of materials happen with the interior and the atmosphere by looking at how much carbon there is around, for example, right? And so the same is true for other element cycles. And so the same could be true for exoplanet.

We had Professor Shields on the podcast recently, and she does. exoplanet climate simulations. We're basically building models of these planets and then trying to make them consistent with what we might understand from JWST. It sounds like you're talking about doing something similar, but you're building models of the internals of these planets to explain then the climate and the atmosphere, which then tells us about the light we're seeing from these planets. So it seems like quite a few steps there from the photons we're getting in JWST to our model of what's happening inside those planets. Incredible that we could learn anything. Yes, absolutely agreed. And what about future mission?

I know there are space telescopes that are going to be looking specifically for planets. Are those going to have the capacity to tell us more about these planets? Or do we need to wait until we can send landers to listen for exoplanet quakes? What I'm most excited about for future exoplanet data has to do with magnetic fields again, right? So if we think Earth having a magnetic field is so important for shielding life on the surface, then it might be nice if we knew that exoplanets had magnetic fields. It may be it's something we should add to the conditions for a habitable planet out there. And there have been some signs, some evidence that we might actually be able to measure magnetic fields of exoplanets.

So there's hope that with even more measurements and so forth, we might actually be able to tell in the future if an exoplanet has a magnetic field today. How would that be possible? Are you looking for like the northern lights equivalent on the planet, seeing the effect of the magnetic field on the atmosphere? So that's one way, kind of. So it's not the northern light itself, but actually the way we found out Jupiter, had a magnetic field. We knew that Jupiter had a magnetic field in the 1960s, even though we'd never been there, because electrons that spiral along the magnetic field lines of Jupiter get really close to the poles into the atmosphere there, right? And that causes Aurora and Jupiter as well.

But it also causes a type of radio emissions to come off of Jupiter. And those radio emissions get beamed out into space, and we could actually measure them here on the surface of the Earth. So we knew about Jupiter's magnetic field in the 1960s before we'd ever gone there because we receive these radio emissions. Same is true for any other planet. Now it turns out that the intensity of those radio emissions is really important. So you need really strong magnetic fields in order to be able to measure them on the surface of the Earth. We have this horrible atmosphere on Earth and it blocks a lot of radio emissions, which is very frustrating, although kind of good for breathing. So I guess you know, you take what you can. Pros and cons. But hey, let's say we put a radio telescope on the

far side of the moon. That would be great for helping to detect radio emissions from exoplanet. So there's that method, but they're also what I would call sneakier methods, right? For example, if you look at the transit spectrum, so if you look at a planet that's going in front of a sun or a star, and you see kind of how wide the planet is, people can already kind of tell if a planet has an atmosphere by the fact that it could have different thicknesses or different radius in different wavelengths. And that, you know, sometimes the atmosphere will let light through, whether the planet itself won't, right? And so that's how we can tell whether something has an atmosphere as what particular wavelengths of light

get through at different distances. The same can be true about a magnetic field. Sometimes a magnetic field can cause certain light spectra, light frequencies to not get through. So we might be actually able to measure a magnetosphere surrounding a planet by looking at transit spectra. You can also maybe see if a planet has like a tail, right?

And so sometimes if atmosphere is being blown off a planet, you might be able to see that in a transit spectrum or through other types of light detection. So there might be some sneaky ways to look for magnetic fields of exoplanes as well. Wonderful. Well, I expect that the next generation of scientists will be even more creative about coming up with ways to extract amazing information from these tiny little blips in our telescopes. Yes, hopefully so. Wonderful.

Well, thank you very much for coming on the podcast and telling us so much about the mysteries that are under our feet and the mysteries that are out there in the universe. Thanks so much. This was fun. All right. That was my chat with Professor Sabina Stanley. Again, she's the author of the book, What's Hidden Inside Plants? which you can get now at all reputable booksellers. Thanks very much for listening. Tune in next time. Thanks for listening.

And remember that Daniel and Jorge Explain the Universe is a production of IHeart Radio. For more podcasts from IHeart Radio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. Ah, come on, why is this taking so long? This thing is ancient. Still using yesterday's tech, upgrade to the ThinkPad X1 Carbon,

ultra-light, ultra-powerful, and built for serious productivity. With Intel core ultra-processors, blazing speed, and AI-powered performance, it keeps up with your business, not the other way around. Whoa, this thing moves. Stop hitting snooze on new tech. Win the tech search at Lenovo.com. Lenovo, Lenovo. Unlock AI experiences with the ThinkPad X1 Carpent,

powered by Intel Core Ultra processors so you can work, create, and boost productivity all on one device. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys, then, every day. 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. Now, hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. This is an IHeart podcast. Thank you.