Daniel and Kelly’s Extraordinary Universe - Things that glow in the dark

Episode Date: December 2, 2021

Daniel and Jorge talk about the biology, chemistry and physics of glowing. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

This is an IHeart podcast. Why are TSA rules so confusing? You got a hood of you. I'll take it off. I'm Manny. I'm Noah. This is Devin. And we're best friends and journalists with a new podcast called No Such Thing, where we get to the bottom of questions like that.

Why are you screaming? I can't expect what to do. Now, if the rule was the same, go off on me. I deserve it. You know, lock him up. Listen to No Such Thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. No such thing.

I'm Dr. Joy Hardin-Bradford, host of the Therapy for Black Girls podcast. I know how overwhelming it can feel if flying makes you anxious. In session 418 of the Therapy for Black Girls podcast, Dr. Angela Neal-Barnett and I discuss flight anxiety. What is not a norm is to allow it to prevent you from doing the things that you want to do. The things that you were meant to do. to listen to therapy for black girls on the iHeart radio app apple podcasts or wherever you get your podcast i'm dr scott barry coughman host of the psychology podcast here's a clip from an upcoming

conversation about how to be a better you when you think about emotion regulation you're not going to choose an adaptive strategy which is more effortful to use unless you think there's a good outcome avoidance is easier ignoring is easier denials easier complex problem solving takes effort Listen to the psychology podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Do we really need another podcast with a condescending finance brof trying to tell us how to spend our own money? No, thank you. Instead, check out Brown Ambition. Each week, I, your host, Mandy Money, gives you real talk, real advice with a heavy dose of I feel uses.

Like on Fridays when I take your questions for the BAQA. Whether you're trying to invest for your future, navigate a toxic workplace, I got you. Listen to Brown Ambition on the IHeart Radio app, Apple Podcast, or wherever you get your podcast. Hey, Daniel, I heard you grew up in Los Alamos, New Mexico, home of the Manhattan Project. Oh, yeah, that's true.

But before you ask, our high school mascot was not the atomic bombs. It wasn't an atami or hydrogen. That would be in bad. No, but we did bomb at all of our home football games. Oh, that's a radioactive topic. But I do have a question for you. All right, shoot. Do people in Los Alamos glow in the dark, you know, because of all that radiation?

No, though that would be useful at night. But I do have an extra eyeball that I try to keep closed in the public. Does I give you extra death perception or let you keep an eye on your kids more easily? It lets me see the world in 3D. Cool, but I guess that makes getting glasses kind of a pain. Kind of a pain. Hi, I'm Orham, a cartoonist and the creator of PhD comic. Hi, I'm Daniel.

I'm a particle physicist, and I don't really glow in the dark. Really? What spectrum, though? Don't you glow in the dark in certain spectrums of light? No, I absolutely do. I should have said, I'm a particle physicist, and I do actually glow in the dark just the way I do and you do and everybody does. We all glow in the infrared. Yes, if we all had, I guess, special night goggles, we would all see each other glow at night.

Yeah, or if we had evolved eyeballs that could see in the infrared. Oh, that would be cool. Yeah, we would be able to tell when people are sick and everything, right, kind of, when they have a fever. That's right. We could spot the virus with our naked eyes. Are you saying everybody has an aura about them, kind of, in some frequencies of light? The physics of oras, exactly. Welcome to our podcast, Daniel and Jorge,

Explain the Universe, a production of iHeard Radio. In which we like to talk about the physics of the crazy, the insane, the quantum mechanical, the black holes, the neutron stars, the centers of galaxies, but we also like to talk about the physics of the every day. Doing physics about the universe means understanding everything we see around us, understanding the microscopic mechanisms that determine everything that happens inside our bodies and outside our bodies.

Yeah, because physics is all, around us. It's not just out there in space and the farthest reaches of the cosmos and black holes and stars and planets. It's also right here all around us and the things that you touch every day and the things that you play with and activate every day. And like you said, in our own bodies as well. Yeah, I think it's sort of amazing and beautiful how physics lets us like peel back a layer of reality and see the tiny little microscopic things that are causing that behavior. You know, the reasons that metals are shiny or that liquids flow or that. gases burn, all of its physics at the lowest level. The rules that govern those tiny little particles eventually bubble up and determine basically everything about the universe. And it's cool to go in both directions to see something you don't understand and take it apart into its microscopic little components and to go the other direction and to understand from the bottom up how the rules of the universe determine our experience.

Did you say physics is at the lowest levels or at the glowest levels? Was that a little unintentional slip there? That's right. Halloween is coming, and so I have glow in the dark things in my mind. Do your kids have those like glow in the dark stars up in their ceilings? They do, but they're getting fainter and fainter every year, maybe because of dark energy. Oh, interesting. I don't think that's a thing, is it? Oh, I see. Are you saying that the room is getting bigger and bigger? And so therefore, the stars are getting fainter and fainter?

No, the universe is getting darker and darker because galaxies are accelerating away from us, faster and faster every year. And so our actual night sky is getting darker and darker. And my kids, Cheap-o, glow-in-the-dark stars are also fading, but for a different reason. So they are accidentally scientifically accurate. Well, that is something that is in our everyday lives, especially around this time of Halloween, glow-in-the-dark things. Things that glow in the dark, that people make little like ghosts and decorations that glow in the

dark. That's right. And if you have physics on the brain, then you look at that and you wonder, how does that happen? And I get a lot of questions from listeners who want to understand the very basics of how light works, how photons bounce off of things and sometimes reflect and sometimes absorb and how you get mirrors and why things look like different colors. And this is a very basic question I remember wondering about as a kid, you know, like how light travels and why things are various colors and how that all works.

Yeah, I do remember in the mid-80s like getting my first glow-in-the-dark thing. I think it was a frisbee maybe or something in a T-shirt. And I just remember thinking like, wow, that's amazing. That's like magic. How does that work? That's right. And the answer is always physics. Well, I have to say when I grew up, I stopped wondering about it because I just look at that and think, oh, that's just chemistry. Just chemistry, right? All you chemists out there, you just got like totally dissed. I'm baiting you to this.

No, it's the wonderful world of chemistry. The magnificent questions answered by chemistry. No, chemistry is too complicated for me. I can't think about all those particles at the same time. I see. You like to drill down to the individual particles. I have utmost respect for chemists and biologists who can think about such complex systems. I like to take things apart and think about a single particle interacting with one other particle. Well, that is a pretty interesting question. How to glow in the dark things glow? And I wish we could we could go back in time and tell my 80s kid self about it. So to the end of the podcast, we'll be talking about.

Why do things glow in the dark? And I guess you mean like certain things? Why do all things glow in the dark? Or why do it like glow in the dark things glow in the dark? Yeah, well, some things glow in the visible. Other things glow in the invisible. And it turns out almost everything in the universe glows in some way or another. And there's a lot of really subtle physics going on about how things absorb light.

When they decide to give it off, what's going on in between. and whether or not we could use that to understand things like black holes. Interesting. I guess all things glow in the dark or at least all things that have a temperature other than zero Kelvin, right? Technically, they glow in the dark.

Almost all things that have a temperature glow in the dark. Almost all things. Interesting. But I guess what we mean today is how do things that glow in the visible light spectrum, those things that glow without any electricity or any kind of a battery source, how do those glow in the dark? Exactly.

What is the physics of that? So as usual, we were wondering how many people out there had thought about this question looking at their star stickies in their ceiling or at Halloween decorations and wondered what makes something glow in the dark. So Daniel went out there into the wilds of the internet to ask people this question. So thanks everybody who volunteered. And if you would like to participate and hear your voice on the podcast and you think you have some good answers, please write to us two questions at danielandhorpe.com. Everybody is very welcome. So think about it for a second. And did you owe a glowworm when you were a kid and ever wonder how it works?

Here's what people had to say. I'm inclined to say temperature is what makes things glow in the dark, but in case of bioluminescence in like fireflies or something, it's probably something else. It might be something involving some biological compound combined with electricity. I'm not sure how that works really. but I'd say temperature is the usual suspect. The first thing that comes to mind is bioluminescence. I'm sorry if I'm saying that wrong. I don't know how to pronounce that in English correctly.

But it's like some fish in the deep water they create kind of their own light. We also see that sometimes with algae in the ocean, but I don't know how that works. I'm guessing it's a mixture of chemicals. I've never thought about that. I know that there are certain chemical processes that can excite electrons in the correct way, and there's also bioluminescence that some organisms have. I think to glow in the dark, you have to be able to generate your own form of energy

and emit that in some way, but I'm not sure of any other specifics. Interesting. A lot of answers here that point to biology. They skip right over chemistry and went to bioluminescence. Man, that's a double insult there. No, it's all part of the same wonderful spectrum of science. But it does make you realize that there are lots of ways that things glow in the dark. You know, there are like algae that glow in the ocean and there are fish.

And then there's also, you know, those watches that have like glow in the dark hands. And I remember as a kid thinking that those were amazing and wondering why they faded as the night went on. It was sort of like they captured some sense. sunlight and then we're like slowly releasing it later like how do you capture photons it's like always imagined like are there photons running around in circles inside those little watch hands and there's also those glow sticks right i mean i don't go to a lot of raves but i've heard that they use glow sticks a lot in those and they're used a lot in like you know Halloween too right yeah absolutely we always deck our kids out with glowing stuff so they don't get run over so there's

lots of ways that you can emit light you know i think we should distinguish between things that like just reflect light and things that actually give off their own light. Right, because I guess you know, like the moon doesn't emit light by itself. We only see it at night because it's reflecting light from the sun. That's right. Most of the light that you see is actually reflected, right? All the light from the sun, when you look at the ground, you're looking at reflected light from the sun. The ground is not like glowing in the visible light. If you turned off the sun, the ground would be dark, right? And the same thing with the moon. The moon has a dark side and a light side. And you You only see the light side because you are seeing light reflected off the moon from the sun.

In the visible light spectrum again, right? In the visible light spectrum, yeah. So, you know, moonlight is actually just sunlight, right? That's been reflected off of the moon, which makes me wonder about all those creatures that, you know, like only can live in the moonlight or whatever, like vampires. Wait, what? There are creatures who can only live in the moonlight? On the moon or here on Earth?

No, mythological creatures. Don't vampires turn to stone in sunlight or something? Oh boy. You're really confusing me here today with chemistry and biology and mythical creatures and visible light. We're doing the physics of vampires today, folks. Daniel takes apart the science of vampires. I mean, you know, the sun itself is actually glowing. It's actually emitting light, but the earth and the moon and all the planets. Like when you look at Jupiter, right, that is reflected light from the sun. Those photons have all shot out from the sun, hit Jupiter, and then come back to your eyeball. Right, yeah. That's pretty cool. to think about, but then do the photons become Jupiter photons, you know? Like, technically, right,

it's not the same photons that came from the sun. Like Jupiter absorbed those photons from the sun, did something that we might talk about later, and then emitted its own photons. Yeah, it's complicated, actually. What happens when a photon hits a surface, it can either get absorbed and then later re-emitted, but that you would really call emission or can actually get reflected, right? And quantum mechanically, to understand what happens during a reflection, is a whole other rabbit hole, which would take a whole other podcast, which we're planning to do in a few weeks, actually. But so those photons are sort of really just still like stellar photons that have been reflected off of Jupiter. If something absorbs the photons and then like

gets hotter and emits it, that's really a different kind of process. They are pretty stellar photons. They're fantastic. But you know, light you see from stars, that's actually emitted from that star. Those stars are glowing. And so when we say something, it's glowing, it really means it's emitting its own photons. It's not just like reflecting somebody else's photons. But today we're sort of talking about things here on Earth that sort of glow in the visible light spectrums sort of on their own without any kind of battery or any light reflecting on them. And so we're going to start with things in chemistry and biology because we love chemistry and biology. We do love chemistry and biology and

chemists, right? They're wonderful people. It's funny how we have to say that in a physics podcast. That's right. I'm not over we're compensating at all. I know. They're lovely people. But yes, there are things in biology that glow in the dark, like algae, right? And some fungi? Mm-hmm.

Absolutely. And so this is what we call bioluminescence. And this is essentially just like some critter that has energy stored inside of it and then releasing that energy in terms of a photon. All right. Photons are just like little units of energy. And when a chemical reaction happens and energy is released, it can be released in lots of ways.

it can, like, heat up, you know, other molecules or you can actually also just emit a photon. And so that's what's happening in most cases inside these bioluminescent properties. And they have a chemical reaction, actually, it's happening. So it's biochemistry. And usually it's like oxygen reacting with this thing called luciferin. It's an enzyme. And there's luciferin and luciferase. And these things interact with oxygen and then release a photon and form some new chemical compounds.

What? Like Lucifer? Like the fallen angel? Or like lucid, like light? I think there's a connection there. Yeah, I think they have the same root. Oh, right. Interesting. So like all bioluminescence is evil is what you're saying. It is a boss of Lucifer or at least this enzyme called Luciferese. This is a surprisingly Halloween themed episode, isn't it? Oh, my goodness. Are you in costume right now? I'm dressed up as a physicist today. Oh, good. Let me get sandals, shorts.

shirt or is a t-shirt optional? No comment. But, you know, this happens in lots of different kinds of creatures. You have, like, bacteria that can do it. You have bugs that can do it, like fireflies. You have fungi that can do it. A deep sea squids can do it. You've probably seen pictures of those fish that have, like, a little lantern that they

have in front of themselves to attract critters to eat. Yeah. Are you saying that those all work with the same mechanism, the same enzyme, or like a similar enzyme? They're all very similar. There's like 40 different ways that this. This has evolved independently, and they all use some variety of a luciferin or a luciferase, though it varies pretty widely between the species.

Wow, that's pretty cool. And I think the point is that they're expending energy, right? They're like using oxygen and they're probably using some kind of sugar, right, to sort of make this chemical reaction work. Yeah, usually it starts out with, you know, your typical energy-carrying molecule ATP in the body, and then it just converts that energy into something else, which becomes a photon. And I guess a big question is kind of why they do those. things, I guess just to sort of see things in the dark or be able to communicate in the dark? It's something that the biologists speculate a lot. In some cases, they do it to communicate like

toxicity, the way like a plant might be brightly colored or an insect might be brightly colored to say like, hey, watch out. Stay away from me. In other cases, they use it to attract prey. Like the lantern fish, you know, uses it to draw things to it because some microbes are attracted to light. And so there's lots of different reasons. You know, some of them they use it to communicate like fireflies or, you know, mating dances. So there's a really wide variety of uses across the various creatures that do bioluminesse. Interesting. And you're saying they all evolved this independently. Like they all came up with the same solution, but they hadn't talked to each other about it. Yeah, they don't have a single common evolutionary history, which means that it's something that's not that hard

to evolve or something that's pretty useful. And it's something I think biologists have sort of learned to hack too, right? Like they can now like tweak the DNA of something or bacteria or something and make it glow right yeah exactly it's not that complicated a process so they can sort of engineer it into something which means in the future you know maybe you'll like be able to biohack your body into glowing in the dark if you'd want that or your kid so you can keep track of him on Halloween night that would be pretty useful just like give him a quick drink they glow in the dark probably there'll be an app on your phone you can like turn your kid various colors you're like where is my kid where is he on the playground or something yeah and you can change their color on the

app too. That would be pretty handy. I know. Then hackers take over and everybody's kid is just like blinking constantly. That'd be crazy. This seems like a bad idea. Or you get a rave and everyone's like has these fun patterns in their skin? But there are actual technological applications. It turns out that miners knew that some fish had a very faint glow in them. And even after the fish were dead, this process continued in their skins. And so miners used to take dried fish skins down into the mines with them as a sort of very, very faint lamp. And your eyeballs are so powerful that even a very small source of light in the deep, deep dark is enough to sort of show you how to get around.

And an advantage, of course, in the deep caves, not to have like an open flame, something that's consuming oxygen and making smoke. Oh, interesting. Yeah. Although I imagine, you know, taking dead fish into a very close and cramped quarter, probably it becomes a bad idea in a short while. There's always tradeoffs. All right. So that's bioluminescence, how living creatures make light in the dark. But there's also sort of the chemistry of it, right? Like we can have glow sticks and we can have those sticky things that glow in the dark and glow in the dark skulls. And at Halloween, how do those work?

There's a lot of ways that you can have chemoluminescence. Essentially, you just need any sort of reaction that releases energy. And sometimes it releases energy in terms of light and not just heat. And so these are pretty simple reactions. What's happening inside those things is you have like a little glass vial that's separating two different chemicals that when they come together, they react and they give off some of their energy. Typically, it's like hydrogen peroxide and then some sort of activator chemical. And so you know how you have to like bend those things and snap them. it's so that the two things then mix and form that chemical reaction.

Interesting. And so what's happening? Like the molecules of one chemical are reacting with the other molecules. And then somehow that process is they rearranged themselves, somehow releases a photon. The end product requires less energy to build than the actual ingredients. And so you've left over energy. It's like these two things have like fallen in together into like a little potential well. So there's leftover energy, which is emitted in terms of a photon.

And so that's chemo and. bioluminescence. That's pretty cool. All right, so let's get into the things that glow in the dark in other ways using physics. But first, let's take a quick break. Imagine that you're on an airplane and all of a sudden you hear this. Attention passengers. The pilot is having an emergency and we need someone, anyone to land this plane. Think you could do it? It turns out that nearly 50% of men think that they could land the plane with the help of air traffic control. And they're saying like, okay, pull this, until this. Pull that. Turn this. It's just...

I can do my eyes close. I'm Manny. I'm Noah. This is Devin. And on our new show, no such thing. We get to the bottom of questions like these. Join us as we talk to the leading expert on overconfidence. Those who lack expertise lack the expertise they need to recognize that they lack expertise. And then, as we try the whole thing out for real. Wait, what? Oh, that's the run right.

I'm looking at this thing. See? Listen to no such thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hola, it's Honey German, and my podcast, Grasias 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 auditioned in, like, over 25 years. Oh, wow. That's some real G-talk right there.

Oh, yeah. We've got some of the biggest actors, musicians, 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 vivras 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, you know, I'm me. Yeah. But the whole pretending and code, you know, it takes a toll on you. Listen to the new season of Grasas Has Come Again as part of my Cultura podcast network on the Iheart radio app, Apple Podcast, or wherever you get your podcast. Your entire identity has been fabricated. Your beloved brother goes missing without a trace.

You discover the depths of your mother's illness, the way it has echoed and reverberated throughout your life impacting your very legacy. Hi, I'm Danny Shapiro, and these are just a few of the profound and powerful stories I'll be mining on our 12th season of Family Secrets. With over 37 million downloads, we continue to be moved and inspired by our guests and their courageously told stories. I can't wait to share 10 powerful new episodes with you, stories of Tangled Up by entities, concealed truths, and the way in which family secrets almost always need to be told. I hope you'll join me and my extraordinary guests for this new season of Family Secrets. Listen to Family Secrets, Season 12 on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

Our IHeart Radio Music Festival, presented by Capital One, is coming back to Las Vegas. Vegas. September 19th and 20th. On your feet. Streaming live only on Hulu. Brian Adams, Ed Sheeran, Fade, Chlorilla, Jelly Roll, Chon Fogarty, Lil Wayne, LL Cool J, Mariah, Maroon 5, Sammy Hagar, Tate McCray, The Offspring, Tim McGraw. Tickets are on sale now at AXS.com. Get your tickets today, AXS.com. We're talking about things that glow in the dark in a fun, fun way, right? Not in a scary way.

That's right. In a sort of joyful you're going to eat chocolate at the end of this night Halloween sort of way. Yeah, probably too much. So we talked about animals and bacteria and fungi that glow in the dark and how to do that with chemicals. But then there's also things that seem to glow in the dark without any kind of reactive reaction or any kind of consumption of sugars or energy, which are, you know, glow in the dark stickers and glow in the dark.

dark decals and t-shirts and things like that? How did those work? Those are more physicsy, right? Yeah, these are more physicsy. And these are really cool because they really are like little batteries. They're like storing the energy from the sun and then slowly emitting it, slowly releasing it. So it really is sort of cool. Like you know how you can charge these up, right? You put it in sunlight and then you rush into the closet and it seems to glow really brightly and then it fades very gradually. But it takes a long time. And so I think of it like delayed reflection rather than just immediately reflecting all the light from the sun, it like it gathers it, it holds it,

and it sort of meters it out for you. The same way, you know, on Halloween, you get a huge bucket of candy, but your mom only lets you have one or two pieces every day. We had two very different moms, I guess. My mom was not that concerned about my candy consumption. Oh, yeah? Or did she just eat it all herself?

We just had no rules, I think. At least I don't remember having any rules. And is that the way you're raising your kids? Eat as much candy as you like whenever you like? No, of course you turn into the, the worst version of yourself as a parent. Now, we meet her out throughout the year. All right.

Well, there you go. That's a good model for the phosphorescence process, which is happening in glow-in-the-dark toys. So what's happening here is that the photon is hitting the object and it's in some low-energy state and absorbs that photon, right? It doesn't just reflect it. It absorbs it, which means that like some electron in that material now has more energy than it did before.

And that's not that unusual. But what happens here is that the electron doesn't just immediately then release that energy instead it gets trapped it's sort of like you've pushed the electron up a hill and then before it can roll back down it gets caught on some ledge or something and it has to hang out there for a while and it's very hard for it to get off that ledge and so you have this like pile of electrons stuck up on that ledge storing that energy and occasionally one will drop down and give off a photon interesting and now is it like one photon per atom or like one electron per atom or can like an atom store multiple photons.

You can't really think about it in terms of atoms because these are objects, so it's really like a lattice, and the electrons are not really like held onto an individual atom. So these electrons are like flowing around this crystal, this lattice of whatever material it is that you're thinking about. And you know, when we think about crystal, you think of like a really hard, firm object, but really any solid you can think about in terms of a crystal or a lattice. It's like a mesh of atoms that are all woven together, and the electrons jump happily around.

And so what happens here is like an individual electron gets energy and then it's like flowing freely, but it can get stuck. Like there's a defect in the lattice or, you know, where the bonds are not perfect or there's like some doping material, some other kind of thing which sort of breaks the lattice. Electrons can get stuck in those little holes. And then they have to wait for like a little bit of heat or something else to sort of knock them out of that hole and down to a lower energy so they can give off that light. And that's why the light is emitted over time. Interesting. But then what happens to the photons? Do they like disappear? They get transformed into a different kind of energy? What happens to the actual photon? So the initial photon, it goes into the energy of the electron, right? And then the electron has more energy. It's like whizzing around inside the lattice. When we say it's trapped, we don't mean it's like physically stuck in a particular physical state. We mean that it's like stuck in a higher energy state. It like can't release its energy. It's stuck in a state where it's very difficult to transition back. down to the lower state. You know, you can think about these quantum states as sort of like

a ladder, but really it's not always easy to go up or down. The connections between these two ladders always require some kind of interaction, you know, some sort of forces involved in going from one part of the ladder to the other part of the ladder. And sometimes those things are difficult to happen. And so you can get stuck in an upper state and very slowly the electrons can leak down to the lower state. So that's what's happening here is that the process that takes the electron that lets it release its energy down to the lower state is rare. It's not like it could happen all the time. And so a lot of the electrons are just like, you know, whizzing around really excited,

like kids that have had too much candy and they can't let that energy go. I see. It's like it captures electrons easily, but it sort of doles them out more rarely. And so that's why you can sort of store light in a way. Like you charge it into the sunlight and then you take it into a dark room and it slowly gives us those photons it absorbed. Yeah. Like imagine a huge.

bowl with a tiny little hole at the bottom and you fill it with ping pong balls, you're not going to get all the ping pong balls out at once. They're all going to dribble out one at a time because the size of the hole is small. And so that's essentially what's happening. And so that's how most glow-in-the-dark toys and stickers work. They all use the same material or are there different materials that do this? There are lots of different materials that can do this. But the process in general is called phosphorescence. It's called fluorescence if you just absorb and immediately re-emmit. And it's called phosphorescence if you absorb and you hang on to it for a little while and then you emit.

And so it's phosphorescence that makes like the hands on your watch glow or your little plastic toy glow or whatever it is. Anything that needs to be charged by sunlight is phosphorescence. Interesting. Is it related to phosphor? Yeah. Well, confusingly, something which is a phosphor is anything which is either fluorescent or phosphorescent.

So that's a confusing set of names there. But the phosphorus is anything essentially that just glows. And I guess can it trap energy in other ways or only three? sunlight? Like can I stick it in the microwave and then it'll glow or rub it really hard or put it over a flame and it'll glow? Do you know what I mean? Like can it or is it only able to store energy from sunlight? That's the most efficient way for it to happen because what you want is for the electrons to get their energy. You don't want to like break up the lattice itself. If you put this thing in the microwave, you're going to melt it. You're going to change the chemical

composition. It's no longer going to be that lattice that can hold that energy in this particular state and emit it over time. So you could destroy it by heating it up. Yes, you're you will be giving energy to those electrons, but the whole process relies on the electrons moving through this lattice. And if you destroy that lattice, then you've messed it up. I see. So don't stick your glow in the darks in the microwave is the main takeaway here today. That's right. Physics tells you don't microwave random stuff. All right. So those are phosphorescent glow in the dark toys, but there are other ways in which physics can make you glow in the dark, right? And some of them are kind of intense. That's right. If you have like an old-fashioned glow-in-the-dark watch, it might have hands

that glow in the dark all the time without needing to be charged by sunlight. And that's a particular and kind of scary process because that's actually radioactive decay. We know that some things, some elements are not stable, like uranium, for example. Uranium hangs out, but it doesn't hang out for the whole life of the universe. Eventually, it falls apart. And it falls apart and gives off some energy. And in some cases, when these things decay, they emit very high energy photons, like cobalt 60 or nickel 60. These are unstable isotopes. And when they decay, they give off gamma rays. Whoa. And they used to put

this in like regular watches for people. Yeah, regular watches for people. And so, you know, they wouldn't put like cobalt or nickel, but they would use things like radium, which is pretty prevalent. And a little bit of radium would give off essentially radiation. And, you know, gamma rays you can't see with your eyes. These are photons, but they're very, very high energy, which means they're small wavelengths, so you can't see them. So they would mix this with something. else which can absorb gamma rays and then emits at a different frequency. So it's called wavelength shifting. It absorbs photon of one frequency and then it gives off photons of a lower frequency, which you can see. It's like little physics batteries, right? You know, you have

energy stored in this radium and it's slowly leaking out and it gets transformed into visible light that your eyeballs can see. Whoa, but aren't these watches dangerous? Like doesn't the radio activity give you some sort of mutation in your genes and stuff like that? Yeah, absolutely. And that's why they're not doing it so much anymore. You know, these things have been phased out. But radium used to be treated a lot more casually. You know, the experiments that Marie Curie did decades and decades ago. And she worked in her lab for a long time. And now her lab is so radioactive that you can't even go inside it. So we're taking radiation much more seriously than people used to. And so yeah, now we don't just like casually paint things with radioactive paint because

it's basically cancer paint. Well, or cancer at least in other ways. There are still pretty dangerous chemicals in some paints. But I guess the question is, like, is all radiation dangerous? Like, if it's just radiating photons, that's probably okay, right? It's like when they radiate other heavier particles that that's the problem. That's the part that gives you cancer, right? Well, it depends on whether or not it has enough energy to penetrate your skin. Are various kinds of radiation?

You can radiate electrons or you can radiate like a helium nucleus or you can radiate a photon. You might think, how dangerous could a photon be? But if a photon is a gamma ray, which means it has a lot of energy, then you can really penetrate your body, just like x-rays. X-rays are also photons, but we're very careful with x-rays because we know that they cause mutations and too many x-rays will give you cancer. And so you wouldn't want like something on your wrist, which emits x-rays all the time. Gamma rays are in the same category. They're ionizing radiation that can penetrate your body and they can do damage. Right, or like UV rays, right, from the sun.

That's why you need sunblock. Yeah, UV are a little. little bit lower energy than gamma rays, but still dangerous. All right. So that's another way to have something glow in the dark is make it radioactive and have that radioactivity kind of work it so that it somehow emits visible light photons. Yeah. And there's lots of different ways you can take advantage of radioactivity.

Remember that some of our awesome like robotic explorers around the solar system take advantage of the same property. They have a chunk of radioactive material, which is slowly decaying and giving off energy in terms of photons or other radiation, which is then captured and turned in electricity and powers those rovers and those satellites. So it's also kind of awesome. It's just not something you should have close to people. Right.

And those that don't glow in the dark, right? Like they're encased in all this sort of material inside of the battery. That's right. I don't think that those things glow in the dark. That would be pretty cool, though, a glow-in-the-dark Mars rover. I think it has a flashlight on it. So it can't technically glow in the dark. All right.

Well, what's another way in which physics can make things glow in the dark? As we were saying earlier, almost everything in the universe does already actually actually glow. It just might not be hot enough to glow in the visible light spectrum. This is something in physics we call black body radiation. By black body, we just mean something that doesn't reflect any light, which absorbs all of the energy of the light that hits it and then emits light based on its temperature. And you're saying everything in the universe does this, right? Everything in the universe does this exactly. And it depends on your temperature. The hotter you are, the higher the frequency of the photons you emit. The colder you are, the lower the frequency of the photons you emit. And that's

why, for example, the earth glows, but it doesn't glow in the visible spectrum like the sun does. The sun, very, very hot, like 5,500 C on its surface, and it glows in the visible light. The earth also glows, but only in the infrareds. You need, like, special cameras to see the earth's glow. And I glow. Like, that's why you can see me in night vision. I look different from things around me because I'm hotter and the spectrum that I emit has a higher frequency than like the table next to me or the ground beneath me. Interesting. Like so like to an alien who could see in the infrared, Earth would look like a star kind of,

then one, but it would still glow in the sky. Exactly. And that's why we build the James Webb Space Telescope, which is going to launch very soon and can see in the infrared because we want to see those planets. We don't just want to study things in the universe that glow in the visible. We want to see things that glow in infrared. red. So that's an awesome telescope that's kept very, very, very cold. So it can be sensitive to these very low energy photons coming from, for example, exoplanets. So we can see how hot those

aliens are, whether they're hot or not. That's right. And you know, you know this already because you know that things glow different colors as they get hotter. Like you have a chunk of metal, it can get red hot and then it can get white hot. So we have a very intuitive sense for how things glow differently as they get hot. And it just turns out that that continues. You know, If something gets super-duper hot, it starts to glow in the UV or starts to give off x-rays. You know, why does the gas around a black hole give off x-rays? Because it's super-duper crazy hot. Well, I guess the question is, what's that mechanism?

Like, why is temperature related to the frequency of the light that's emitted by something? Or I guess even a step further back is like, why do things that are hot glow at all? Yeah, it's a great question. It's just basically entropy. You have a bunch of energy in a small space and you have stuff nearby that doesn't have as much energy, then that energy is going to transfer. And one way for that to happen is for things to emit photons. So basically everything that has charged particles inside of it, electrons or atoms or whatever,

is constantly just giving off photons. And so if you have something nearby that isn't as hot, then it's going to be accepting those photons. So basically, you know, electrons as they move around are constantly just radiating away photons. Mm. Just because they're decaying? Like decay?

Is it sort of like a decaying process? like the electrons just suddenly like, hey, I give up. I'm done with this universe. I'll just chill out and emit a photon. Sort of. It's sort of like, you know, like a bath. You know, electrons aren't just like flying around holding onto their energy. They're constantly like transferring it back and forth to each other

and between themselves and the atoms nearby. And if you're at an edge of an object, then some of those photons instead of getting like absorbed by another atom or absorbed by another electron, just fly out into the universe. With the electron or the photon? The photon. It's sort of like if you're, you know, if there's a party, everybody's talking to each other, everybody's sort of in the middle of this soup of conversation. If you're in the outside of the party, you're going to hear some of that conversation because some of those voices are pointed in your direction accidentally.

It's not going to be as intense as if you're actually inside of it, but always leaks out energy, always spreads out through the universe. And this is just, you know, another way for that to happen. Yeah, I guess if you're at like at the edge of that party, not that many people are talking to you. So you might be like, yeah, I'll just go home and watch some Netflix. And so you leave the party. And so, like, eventually the whole party sort of evaporates, right? That's the idea. Everybody just goes home and eats their Halloween candy in silence eventually.

Yeah. So that's kind of what's happening in your body right now, which is, like, you know, some of the atoms and electrons at the surface, they're just like, you know, spontaneously giving off photons. Yeah, it's a spontaneous process of just like the radiative distribution of entropy. Why does hotter body correspond to a higher frequency of the light that you emit? Because higher frequency is higher energy. So as the body gets hotter, right, there's more energy stored inside of it than it's possible for it to emit photons at higher energy. So it's actually a whole spectrum. It's not like there's a single wavelength emitted by a certain object based on a temperature.

It's a whole spectrum. Something that's really hot emits at low frequencies and at high frequencies. Something that's cold only emits at the lower frequencies because it doesn't have enough photons inside of it to emit the higher frequencies. Interesting. So this is where it gets a little bit confusing too because sometimes what people call a star is really, just like a hard body in space. Yeah, exactly. The future of our star is to become something called a white dwarf. When all the fusion has finished and it's blown out a huge amount of its mass into space, the core of it will collapse into a very heavy blob of stuff that's not capable of fusing

anymore. But it'll still be super duper hot. And this is what we call a white dwarf. And, you know, we call it a star or some people call it a stellar remnant. It's going to be really hot. And it's called a white dwarf because it's going to glow white hot. You know, I think it's going to be tens of thousands of degrees. And so it's going to be glowing into the universe and looking like a star, but no fusion is happening inside of it. It's just because it's hot, right? It's just glowing because it's hot the same way that like, you know, metal that you've taken

out of a forge glows because it's hot or a light bulb glows because it's hot. Right. And but technically, there is some sort of reaction going on, right? Things are breaking down. And so that's why it's emitting light. Well, it's just sort of this spontaneous. redistribution of energy, you know, anything that's hot is going to glow and give off its energy and cool down, essentially. And the future of these white dwarfs is not that they're going to

chemically change, right? They have a lump of iron. It's going to stay iron. But they will cool down and in trillions of years eventually become black dwarves. Wow. So ironically, it'll still have the same meaning. It'll literally become a black body eventually. All right. Well, let's take it up a notch, Daniel, and let's talk about bigger and crazier things in the universe that glow in the dark, like black holes and dark matter. But first, let's take another quick break. Imagine that you're on an airplane and all of a sudden you hear this.

Attention passengers. The pilot is having an emergency and we need someone, anyone, to land this plane. Think you could do it? It turns out that nearly 50% of men think that they could land the plane with the help of air traffic control. And they're saying like, okay, pull this until this.

that turn this. It's just... I can do it my eyes close. I'm Mani. I'm Noah. This is Devin. And on our new show, No Such Thing, we get to the bottom of questions like these. Join us as we talk to the leading expert on overconfidence. Those who lack expertise lack the expertise they need to recognize that they lack expertise. And then as we try the whole thing out for real. Wait, what? Oh, that's the run right. I'm looking at this thing. See? Listen to No Such Thing on the Hi Heart Radio app, Apple Podcasts, or wherever you get your podcasts. 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 when it weighs on you. It's really easy to just like stick your head in the sand. It's nice and dark in the 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.

Your entire identity has been fabricated. Your beloved brother goes missing without a trace. You discover the depths of your mother's illness, the way it has echoed and reverberated throughout your life, impacting your very legacy. Hi, I'm Danny Shapiro. And these are just a few of the profound and powerful stories. I'll be mining on our 12th season of Family Secrets. With over 37 million downloads, we continue

to be moved and inspired by our guests and their courageously told stories. I can't wait to share 10 powerful new episodes with you, stories of tangled up identities, concealed truths, and the way in which family secrets almost always need to be told. I hope you'll join me and my extraordinary guests for this new season of Family Secrets. Listen to Family Secrets Season 12 on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. 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. and 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. All right, we're talking about things that glow in the dark. And ironically, in this universe, things that have the name Black and Dark, also glow in the dark. That's right. It's weird to think of a black body is something that glows in the dark.

Like the sun is an almost perfect black body, right? It's just another example of physics using words that we find familiar in ways that make no sense. What do you mean? The sun is a black body? The sun is a black body. What they mean by that is that the sun absorbs almost any light that hits it. It doesn't reflect any light. Black body just means no reflection.

You can absorb light and you can emit light because you're hot, but there's no reflection. So when you say we model this as a black body, we just mean that there's no reflection. And the sun absorbs almost any light that hits it. The sun is not a good mirror. Yeah, I guess any light that hits it just goes into that crazy plasma that is inside of it, right? Yeah, and heats it up and then it will emit again, but it's not a reflection. All right. Well, I think you were telling me earlier that black holes also glow in the dark.

Black holes do glow, which is super awesome. And people might be familiar with this because the whole idea of hawking radiation. But I think it's interesting to understand the origin of this idea. Like how did Hawking come up with the concept that black holes might give off radiation? And it came from thinking about the temperature of things and how things glow, this connection between how things that have temperature seem to glow. So he and his student who's named Beckinstein were thinking about this. Like what is the thermodynamics of black holes?

And so Hawking's contributions to physics and the black holes is much more than just like realizing that there might be some radiation leaking at the side is from thinking about black holes in terms of thermodynamic quantities like what is its temperature and what is its entropy. And very quickly they realize that black holes have to have some entropy because entropy is conserved. Entropy always increases in the universe. And when something falls into a black hole, you can't just like delete its entropy, which means the black holes have to hold some entropy. And if they have entropy, then they have to have temperature. You're using entropy. sort of as a standing for like heat and energy.

Well, they're definitely connected, right? Remember, entropy is like a measure of the disorder of a system, sort of. It's like the number of ways you can rearrange the microscopic state of an object to be consistent with its macroscopic state. And so something that has a lot of temperature is going to have a lot of entropy because there's a lot of different ways you can rearrange it. And so if you have something and it falls into a black hole, it carries with it some entropy. It's sort of like thinking about information, right? You know, where's the information for something that falls into a black hole? It goes into the black hole.

So black holes have to have information. And the folks that work on the black hole information paradox, this question about what happens to information that falls inside the black hole, they tend to think about it in terms of entropy also. Basically, Hawking said that, you know, black holes are not just like a spot of nothing. They have something to them. They have something to them. They have some entropy.

They have to have some temperature. And if they have some temperature, they have to glow because everything in the universe that interacts electromagnetically, right? Everything in the universe that has some energy localized into it tends to give off some of that, tends to radiate that away, just like a white dwarf or just like the sun or just like that piece of metal you stuck in a forge or just like the earth, everything should glow. And so to sort of make sense of this mathematically invented this whole field of black hole thermodynamics and out of it came this concept of hawking radiation that even black holes give off radiation because they have a non-zero temperature.

Right. But I guess the problem is that, you know, black holes are supposed to be things out of which nothing can come out. So even if it has, you know, information or entropy or energy inside of it, how does that energy get out if nothing can come out of a black hole? Right. And classically, according to general relativity, which is a classical theory, meaning that it ignores quantum mechanics, you're right. And classical black holes do not emit anything. They're just one-way doors of information and objects. And so the way we usually talk about black holes on this podcast is in the realm of general relativity because it's the only idea we have to describe black holes. But we know that general relativity isn't right because general relativity is not

consistent with quantum mechanics, which we're pretty sure is the law of the universe. And so what Hawking tried to do was like take first steps towards a theory of quantum gravity, a quantum mechanically consistent description of black holes. He wasn't able to do that. We don't have a theory of quantum gravity. What he did was sort of take general relativity and try to tweak it a little bit to make it a little bit quantum mechanical. It's like semi-classical now.

And so he's got sort of like a patched up version of a theory of black holes that's not 100% like general relativity, but also not fully consistent with quantum mechanics. He still has holes in this theory, that's what you're saying, about black holes. Yeah. And that's why, for example, we don't have a good. microscopic understanding of Hawking radiation. People talk about, you know, virtual particles being produced at the edge of a black hole. And there's some hand wavy stories, which we've given sometimes on this podcast. But the truth is none of those are correct. They're sort of like hand wavy stories that

give you a sense for what might be happening. But we don't have a good microscopic understanding of what's going on because we don't understand the gravity of quantum particles. So Hawking has sort of like a statistical argument for why black holes should emit radiation, which comes from them having temperature and therefore needing to radiate, but he doesn't have like a good quantum description of what's actually happening to these particles near the edge of the black hole. We don't have that because we don't have a theory of quantum gravity. He has sort of like a band-aid on top of general relativity that lets him do a few calculations, but later people are going to realize that it's like an approximation of the true theory. So he predicts that black holes will glow in the

dark, but we don't know how they would glow in the dark, but have we actually seen a black hole glow in the dark or is this all still a prediction? We have not. Nobody's ever observed hawking radiation. Remember, it would be really, really faint. Hawking radiation happens more dramatically for smaller black holes. So for large black holes, like the few that we have seen, it would be really, really faint. And large black holes tend to be surrounded by other things that glow very brightly, like accretion disks of very, very hot gas. So it would be very difficult to observe hawking radiation. The best way to do it would be to create a tiny black hole, like a really small one that we could study here in the laboratory before

it gobbled up the earth because it would evaporate rather quickly and it would give off a lot of hawking radiation. So no, we have never seen hawking radiation. So it's still just a theory. But it's very convincing and it lets people do lots of other calculations about black holes. And so there's a whole theory built on top of it. All right. So that's one way in which black holes can technically glow in the dark, but they also sort of glow because they have all this gas around them, right? That it meets a lot of radiation. That's right, yeah. And so that's sort of like the black hole system. The black hole itself, of course, doesn't glow, but the stuff around it that's getting like squeezed by all the energy from the black hole does glow. All right. And so the other big universe thing that glows is dark matter. Dark matter itself also glows, you're saying. We don't know if dark matter glows. It's really a fascinating question because we say that everything in the universe that has a temperature glows, right? But the caveat there is that it has to have some sort of electromagnetic interaction. Like, why do things glow? As we were saying before,

it's because the electrons inside them are whizzing around and giving off photons. But if you're made of things that don't interact with photons like dark matter, then you can't give off photons. So it might be that dark matter has a temperature. Like we know it has a temperature. It moves. It has a speed. But it might be that it doesn't glow.

It could be the only thing in the universe that has a temperature but doesn't glow. Interesting, right? Because it doesn't know how to talk to the electromagnetic radiation. It doesn't interact with it or. know how to talk in that language or give it off. And so it has all this energy. And so how can it be glowing in a sort of energy sense? It depends on how dark matter interacts. We know that dark matter feels gravity. It can talk to things via gravity. It might be that it has some other force. Like there's some weird new dark electromagnetic force we never heard before. And maybe it can glow using dark photons,

right? But that's all speculation. So put that aside for now. We do know that it feels gravity. And so it might be that dark matter can glow gravitationally, right? For example, black holes that interact with each other and combine, they give off gravitational radiation. That's gravitational waves. And so dark matter might be able to give off like very faint gravitational waves as it's just sort of sitting around, sloshing around the universe. That's sort of like a faint glow, not in photons, but in terms of other kinds of radiation.

Right. Interesting because I think we can detect gravitational waves, but only from like these. these incredible events like two black holes colliding because that's how faint gravitational waves are. Are you saying that dark matter might be giving off also gravitational waves, but they would be so small and indetectable that we would maybe never see them? You and I are giving off gravitational waves. Anybody in the universe that has mass and accelerates gives off gravitational waves. But as you say, because gravity is so weak that's undetectable, you have to be an incredible mass undergoing incredible acceleration to feel those gravitational

waves. Wait, you and I are glowing in the gravitational field. Yeah, absolutely. But only if we move, though, if we stay still, we don't. Or do we? Or are you saying our atoms are emitting gravitational waves? All of those, yeah. If we accelerate in any way, then we are giving off gravitational waves. So as we move around the sun, that's circular motion, that's acceleration. As the sun moves around the center of the galaxy, it's glowing gravitationally. But these things are very faint. And even the atoms in our body, which do that, which accelerate in any way, they give off gravitational radiation. We have a podcast episode you might remember about the cosmic gravitational background.

It's like the sum of all these little gravitational waves that you can't really discern because they're all so dim. They just add up to like a general hum. But I guess what you're saying is like, you know, the fact that we have a temperature means that our molecules are vibrating. In that vibration, they are emitting gravitational waves. Yes, absolutely they are. Very, very faint, probably never detectable, but technically yes. Whoa, that's pretty cool. So we're all hot and glowing in some sense.

Exactly. And so even dark matter, which we can see with photons, might be glowing gravitationally. And this also gets into quantum mechanics, right? There's something called the ultraviolet catastrophe. Yes, the ultraviolet catastrophe was one of the first clues that told us about quantum mechanics. And when people first calculated how black bodies might radiate, like at what frequency should an object radiate given its temperature, they did some basic calculations using. using electromagnetism and they got these crazy predictions. They predicted, for example, that an object at a thousand degrees Kelvin should emit an

infinite amount of energy because there's an infinite number of ways for a photon to glow. There's an infinite number of like different wavelengths a photon could have they thought. And so they got all these crazy numbers which obviously didn't agree with their experiments. You know, you put something in the toaster, it doesn't like explode with infinite energy, right? The sun is not exploding with infinite energy. Well, it depends on what you put into the toast or oven. Put in too much Halloween candy and pop rocks, it might explode with energy. Yeah, some Mentos and Coke, who knows?

But this was known as the ultraviolet catastrophe like 120 years ago because people didn't understand why this wasn't happening. The calculations suggested it should. Obviously, it wasn't. And it wasn't until a young physicist named Max Plunk realized that if you made this weird assumption that photons couldn't have just any arbitrary energy, but that they came in steps that they were like, quantized units of energy, then that killed the problem because it meant that there weren't an

infinite number of modes for photons to have. They're just a finite ladder. And the way the math worked out, that meant that it solved the problem. And it predicted perfectly the experiments. And so Plank was like, oh, well, maybe things are quantized. Interesting. So actually, quantum mechanics sort of limits how things glow in the dark. Like things would glow in the dark more if it wasn't for quantum mechanics. Yes, exactly. Quantum mechanics limits how things glow. And things glowing in the dark was one of our very first clues that the universe is quantum mechanical. And it was Einstein actually who recognized this. Plunk just said, like, I don't know what this means, but if you make this assumption,

the math all works out. And Einstein was thinking, hmm, and he read about the photoelectric effect, check out a whole podcast about the discovery of the photon. It was Einstein who put it all together and said, oh, maybe photons travel in chunks that they are quantized in units. I guess this ties it all back. Things glow in the dark. At the end of it, the day, it is a very fundamental and quantum.

mechanical process. Yeah, and asking questions about why things glow and why they don't glow and why they don't explode when you put them in a toaster can sometimes reveal crazy secrets about the nature of the universe, like quantum mechanics. And so asking questions about like dark matter glowing and black holes glowing might help us in our struggles to understand the big questions of today's physics. What's the universe made out of and what is the quantum mechanical description of space and time? Yeah, and it sort of I guess reminds you a little bit that the universe is kind of speaking to us all the time, even in the dark, you know, even in the dark, you know, animals and bacteria and creatures glow and you can mix chemicals

to glow as well. And things out there in space are glowing all the time. And even yourself within you are glowing. That's right. And all those stars out there in the universe that are sending you photons, they're telling you about themselves. They're telling you stories about what they are burning and what they are made out of. The university is like screaming information at us. And to me, the frustrating thing is that most of the time, we aren't listening. Yeah, except they're saying, eat more candy. Eat more candy. So maybe it's good that we don't listen to them all the time. I think you should give your kids an extra piece of candy for this podcast.

Oh, yeah. I'm sure they sneak some anyways. All right. Well, we hope you enjoyed that. And maybe this Halloween or in general look at things in the dark a little bit differently because everything is glowing in the dark. And trying to tell you answers to the secrets of the universe. Thanks for joining us. See you next time. 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.

Why are TSA rules so confusing? You got a hoot of you? I'm gonna take it all! I'm Manny. I'm Noah. This is Devin. And we're best friends and journalists with a new podcast called No Such Thing, where we get to the bottom of questions like that. Why are you screaming at me? I can't expect what to do. Now, if the rule was the same, go off on me. I deserve it. You know, lock him up.

Listen to No Such Thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. No such thing. I'm Dr. Joy Hardin-Bradford, host of the Therapy for Black Girls podcast. I know how overwhelming it can feel if flying makes you anxious. In session 418 of the Therapy for Black Girls podcast, Dr. Angela Nealbornette and I discuss flight anxiety. What is not a norm is to allow it to prevent you from doing the things that you want to do, the things that you were meant to do.

Listen to therapy for Black girls on. on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Your entire identity has been fabricated. Your beloved brother goes missing without a trace. You discover the depths of your mother's illness. I'm Danny Shapiro. And these are just a few of the powerful stories

I'll be mining on our upcoming 12th season of Family Secrets. We continue to be moved and inspired by our guests and their courageously told stories. Listen to Family Secrets Season 12, on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. This is an IHeart podcast.