Daniel and Kelly’s Extraordinary Universe - What's the biggest star in the Universe?

Episode Date: February 4, 2021

Daniel and Jorge talk about mind-blowingly huge balls of burning gas. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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Listen to the Good Stuff podcast on the iHeartRadio app, Apple Podcasts, or wherever you get your podcast. Can you? Do you have an infinite number of neurons? No, but it feels like I've eaten an infinite number of cookies during this pandemic. It does feel like it's dragging on until infinity. But, you know, even if you ate 100 cookies a day, that's not even a million cookies a year. Although, that's a good goal to have. You're right. And honestly, it's hard to visualize a number bigger than like 100 or 1,000.

Anything else in my head, frankly, it's just like a lot. A bunch. A zillion. So then how do you think about how big things are out in space? Like Jupiter or the sun or the galaxy? Like, how do you conceive or think about the mass of such huge objects? I just use the unit of cookies. Jupiter is a whole lot of cookies.

It's a pandemic worth full of cookies. It's the biggest cookie jar in the universe. That's my goal in this pandemic to eat one Jupiter's worth of cookies. Then you look like Jupiter. I think we just wrote Jupiter's formation story for the comic book series. Hi, I'm Jorge. I'm a cartoonist and the creator of PhD comics. Hi, I'm Daniel. I'm a particle physicist, but I have strong opinions about cookies. Do you really? Like a positive or negative? Like, you're never ambivalent about cookies?

I'm never ambivalent about cookies. A very specific taste for what makes a good cookie. Really? According to you? Or do you think you have some sort of universal standard of cookie goodness. I would not want to be the cookie spokesperson for humanity, but I have strong reactions to cookies, yes. Really? What do you think about chips of hoy cookies? Those are not cookies, my God.

Those are cardboard simulcrums of cookies. Oh, man. Well, welcome to our podcast. Daniel and Jorge explain the universe of cookies. No, just a regular universe, the other universe. A production of I-Hard Radio. In which we take our cookie-fueled brains on a tour of everything in the universe, how it works, how big it is, how small it is.

Nothing on this podcast is too vast, too incredibly huge for us to try to wrap our minds around, nor is it too small for us to try to penetrate with our intellect and get a grasp of what's going on down at the tiniest level. Yeah, because it's pretty hard sometimes to hold the whole universe in your head. I mean, you have to hold not just the tiny microscopic particles that everything is made out of, but you also have to hold the ginormous structure. that are out there in space, those huge suns and stars and galaxies and solar systems and clusters of galaxies, it's a big universe. It is a big universe. And often we just rely on math

as like a mental scaffolding to take us where our minds have a hard time going. We talk about these numbers. But it's good to understand that these things are real. When we talk about these objects that are out there, they're real, they're out there. There's actually enormous vast burning plasma balls in the sky. This is not a joke. This is not just notation. It's reality. Yeah, there are giant cookies as well, the size of Jupiter.

You know, I always say we shouldn't be surprised by anything we discover in the universe. But if Hubble turns of enormous planet-sized cookies, I would be surprised. And delighted. Depends on what's in the cookie, man. And hungry. If they're Jupiter-sized chips-a-hoes, I'm out. Well, on today's podcast, we'll be tackling another one of our extreme universe series. in which we talk about the biggest things in the universe,

the hottest, the coldest, the emptiest spaces in the universe. We like to talk about extreme things. Yeah, because the extremes tell us what the limits are. That's what reveals what the rules are. When you push the universe to the edges of what it can do, you understand why it can do something and why it can't. So the extreme universe series is not just fun because it blows your mind, but also it teaches us something about the way the universe works.

Yeah, it's extremely educational. as well. So on today's podcast, we'll be tackling one of these extreme things in the universe and we're doing something a little different today. That's right. Today we have a guest who will be asking the question of the episode for us. Yeah, he's kind of a bit of a celebrity online, right? Yeah, absolutely. He's definitely the youngest host of a science podcast that I'm aware of. Yeah. So here is our special guest to introduce the question. Hello, it's my pleasure to welcome to the program today's special guest question asker, tie, Poole. Ty, say hello to everyone. Hi, I'm really excited to be here. I'm a little bit nervous,

but mostly excited. Well, welcome to the program. Why don't you tell us a little bit about yourself and your podcast? Well, I'm 14, just started high school. I'm here in Toronto, and I host a CBC podcast called Ty Asks Why, the journey of a kid just asking questions, because, you know, my curiosity got the better of me. You asked so many questions. You asked so many questions that they decided you should host a podcast about it. Yeah, pretty much. And what kind of topics does your podcast ask about or answer? Well, we have a wide range of stuff. You know, it can get kind of silly, stuff like, why do we dance or how do songs get stuck in your head? But we also deal with deeper ones, like what is love and what is death? And then, of course, we get to some really

crazy ones like the end of the universe and a pretty topical one about viruses. Awesome. Well, it sounds like a lot of fun. Here on the program, we are definitely big fans of curiosity for folks 99 or even down to 9 years old. And I've listened to a bunch of episodes of your podcast. It's a lot of fun. So congrats. Thanks. I'm really honored. I recently listened to your episode about John von Neumann. And I think it's really cool because he's a really cool guy. He just is in the background of a lot of science things, but he did a lot. Yeah, he definitely was a curious person. All right. So then let's dig into today's episode. we have you on to be our guest question asker. So why don't you introduce for our listeners what today's episode is about? Well, I got another question and I decided to be a good idea to ask you guys. So the question for this episode is, what is the biggest star in the universe? Awesome.

I love that question. But tell me first, what tickles you about that question? What makes you curious about the size of stars? Well, it's just kind of thinking about the sun and it's a strange thing to think about. It seems like really big and scale of our planets and stuff. But I kind of learned and realized that our sun's not very big in comparison to other stars. So it kind of just got me thinking like, how big could we really go? You know, can we get something that's like twice the size of our stun?

Is that the biggest? Or like a million times we go like really, really big. Awesome. Well, I love your expectation that the universe will surprise you, will shock you. Because I think there's a lot of examples in history where we learned something about the universe. and we are totally surprised at the size of things about the scale of the crazy stuff that's going on out there in the universe.

Yeah, I kind of just was in the mood to get my mind blown, you know? I'm excited to hear the number. It's going to be crazy. It's going to be like a billion or something. All right, well, thanks very much. We'll hope to blow your mind. All right.

That was Ty Pool host of Ty Ask Why. And like him, I think we're all ready to get our mind blown. That's right. It's a lot of pressure, though. So, right, he's really expecting a big number. Yeah, yeah. Because, you know, I bet there are huge stars out there in the universe.

There are huge stars out there in the universe. And Ty was reaching for what he thought was like a vast number, a star, a million times bigger than our son. But actually, we're going to deliver something much, much bigger than that. Bigger than a million times the size of our sun. That's right. Wow. We're going to make our sun look like a tiny dust speck. A shiny, tiny dust speck.

All right, well, as usual, you also went out there into the wilds of the internet to ask regular listeners what they thought of this question. That's right. So thank you to everybody who stretched their minds and tried to imagine an enormous star out there in the universe. And if you would like to respond to tough questions from a physicist without any reference materials, please write to me to Questions at Danielanhorpe.com. So think about it for a second. If someone asked you, what you thought was the biggest star in the universe? What would you say? Here's what people had to say. I think that a big factor for determining how big a star can get, I think it's gravity.

Well, one thing for sure is they always discovered something that is bigger than they thought it would be. I know that stars can get much more massive than our own sun. I do not know how big a star can get, but I know that at a certain point, when it passes a certain threshold, it will collapse. on itself and form a black hole. All right. Well, the answer seem to be all over the place. Big answers and small answers. Yeah, exactly. Definitely people are

prepared to have their minds blown and to be surprised. I think one thing we've learned in our exploration of the universe is that what we expect is very rarely what's actually out there. Yeah. Well, I think maybe to start us off, maybe we should settle this

technical question, which is I think is important. What do we mean by biggest star. Do we mean biggest in volume, like the one that occupies the most space or the densest or most massive star? What are we talking about here? Most paparazzi following them around taking pictures, maybe. Yeah, most Instagram followers. Biggest box office. That's right. That's what it takes to be massive on social media. No, it's a fair question. You can make an argument in either direction. Mass is really important in determining the life cycle of a star and what it means, but volume is also a big deal.

Really, in the end, maybe what we're talking about is like the physical size of these things. Yeah, because when you see it, when you're in front of it, that is what you would think about when you think about the word big. Like, oh, wow, that's big.

But if it was small and dense, you'd be impressed, but you wouldn't say, wow, that's big. Yeah, well, it's a big deal, right? It makes a big dent in the structure of the universe. It's like a large gravitational well. I mean, black holes are not a tiny thing to be ignored.

And I think initially I would have voted for the math. mass of the star because that really does tell you about the nature of the star and also like its fate. The entire fate of the star is determined by how much stuff it has. If it has a certain amount of stuff, it's going to end up as a white dwarf. If it has more, it's going to become a neutron star or eventually a black hole. All of that is determined by the mass of the stars. They're really important way to categorize stars. And I guess it doesn't change because the volume of a star changes, right? Like stars go through a life cycle and they grow and they shrink and they end up small at the end, right?

It's a varying quantity. But the mass doesn't really change, does it? It doesn't change that much. I mean, the end cycle of a star, it does blow off some of its outer layer. So, for example, our sun is going to end up as a white dwarf and it won't have all the mass that it had in its early part of its life because it's going to blow out a huge amount of that into like a planetary nebula. So it does sort of change. But, you know, you might say that by the time our sun becomes a white dwarf, it's no longer.

longer a star, right? Because it has no more fusion going on inside of it. To see this celebrity now. Exactly. Can't even get into the hottest restaurants in L.A. anymore. It's in dancing with the stars. Exactly. But volume, you're right, it's variable. Star can grow a lot during its life cycle.

So if we just look out into space and compare two stars, we might be comparing two stars that eventually would have the same size if you sort of lined them up. But one of them is like a grandpa star that's really big at the end of its life. The other one is like a baby star that's more condensed. Okay. So then we're really talking about the mass of the star then. Like what's the most massive star? Yeah, I don't know. I'm honestly on the fence about it because the mass of the star is also important for other reasons. Like it tells you about the history of the universe. You know, the very early universe, stars were much bigger and hotter and burned faster because

there weren't these pockets of metal to collapse smaller stars. And later on, the stars that were formed are smaller and last longer. So that's really important. On the other hand, when I think about what is the biggest star in the universe, I definitely am thinking about volume. I want my mind blown by the sheer amount of space that this thing takes up. Right. It's a tough call, so why don't we do both? All right, we're going to hand out two awards, right? We're just going to, like, dilute the value of our prizes by giving out two of them.

Make two categories, you know, like the Peace Nobel Prize and the actual Nobel Prizes. You mean the one in chemistry, right? That's exactly what I was thinking, yeah. All right. So let's talk about Mo's massive star and also most, I don't know, voluminous star. Biggest, man. It's just biggest. Oh, I see. The most volume is just the biggest. All right. So let's jump into it, I guess. What do we talk about when we talk about mass? Yeah, well, we had a fun podcast a week or so ago about how massive stars can get, how big they can get, how small they can get. And we also talked recently about like, where's the threshold between a planet and a star?

And really the definition of something that's a star is something that can fuse hydrogen. And in order for that to happen, you just have to have enough mass. Just like a minimum mass threshold. You don't have enough stuff, enough like hydrogen gathered together and then compressed down, then you can't get fusion going. And the minimum threshold there is something like about 100 times the mass of Jupiter. Does it have to be hydrogen though, right? Some stars confuse other elements.

Yeah, the heavier stuff like helium or carbon. carbon or neon or oxygen, that takes even more mass in order to get that started. But you're right, there is like a special category of star called a brown dwarf that doesn't fuse hydrogen itself. It fuses an isotope of hydrogen called deuterium. So if you have like 50 Jupiter masses or actually anything between about like 15 to 80, you can get a form of fusion going. It's called Deuterium fusion. It's not like as bright and as hot as normal hydrogen fusion. And so there's, I think, a disagreement about whether or not you would call this a star. It doesn't have regular hydrogen fusion. So it's called a brown dwarf, also sometimes called a failed star. Oh. And so the smallest thing

you would really call a star is about 100 times the mass of Jupiter, and it can really fuse hydrogen. And you call these red dwarfs. It's actually the most common kind of star in the universe. These red dwarfs, they're everywhere. Meaning like if you take 100 Jupiters and you put them on the same place, they will become a star? Yes. If you took 100 Jupiters and put them all in the same place, they would collapse and they would start fusion. The interesting thing is that they actually wouldn't be much bigger than Jupiter because there'd be so much gravity that would pull it together. So a red dwarf is not actually bigger than Jupiter. It's just much more dense. It has 100 times the mass. And that's enough to get hydrogen fusion going. And what would they look like

if you saw them? Like would they look as bright as our son? No, they're not nearly as bright. Because there's a very strong relationship between the mass of a star and its brightness. And as the mass goes up, the brightness increases by the power of four. So a star that has like a tenth, the mass of the sun has much, much less brightness. It's like one ten thousandth of the brightness of the sun. And in fact, the closest red dwarf Earth is called Bernard Star is too dimmed to see by eye, even though it's pretty close. All right. So you take 100 Jupiter's, you put it in together, you start fusing in the middle. And is it basically like a more like a simmering ball of fire? Or is it only happening in the core, for example?

No, it's definitely a ball of fire. Like, if you were near, you would get fried. It's still very hot. It's just not nearly as bright as a larger star. Mm. All right. So that's the minimum star. That's the minimum star.

And the amazing thing about the minimum star is that remember that big stars burn hotter and so they burn faster. These small stars are just sitting there like glowing embers and they're going to last a long, long time. Like these red dwarfs, they could last for 10 trillion years. 10 trillion years and would never run out of 50. fuel or anything? Yeah, because they're just very slowly burning their fuel. They're much cooler than our sun, which is why they're much less bright. And so they're sort of like conserving our fuel. The biggest, brightest stars will only last like a few million years. The smaller stars that are not as big and not as hot, they can go on for trillions of years, much, much longer than the

age of our universe so far. They're like those TV actors that get work forever on TV, but they're not as, they don't shine as brightly on the big screen. That's right. Christopher. walk in, for example. No, Michael Cain, that guy's still working. All right, well, so that's the minimum star. And so let's crank up the mass dial and get into more massive stars. And then we'll get to the actual biggest stars. But first, let's take a quick break.

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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. Listen to no such thing on the Iheart radio app, Apple Podcasts, or wherever you get your podcasts. I had this, like, overwhelming sensation that I had to call it right then. And I just hit call, said, you know, hey, I'm Jacob Schick. I'm the CEO of One Tribe Foundation. and I just wanted to call on and let her know

there's a lot of people battling some of the very same things you're battling and there is help out there. The Good Stuff podcast, season two, takes a deep look into One Tribe Foundation, a non-profit fighting suicide in the veteran community. September is National Suicide Prevention Month,

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right leg and the traumatic brain injury because i landed on my head welcome to season two of the good stuff listen to the good stuff podcast on the iheart radio app apple podcast 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 heart 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. All right, Daniel, we're on the hunt for the most massive stars in the universe and also the biggest stars in the universe.

Yeah. Physical stars, like the shiny kind that's out in space. Astrophysical stars. Unless you're suggesting that Hollywood celebrities are non-physical, that they're like supernatural. They are very ethereal. They transcend physicality. That's right. So the next thing up after red dwarfs are stars like our sun, which you call a yellow dwarf.

and our sun like it's not nearly the biggest or most massive star in the universe but it's huge you know compared to the size of the earth which already is like staggeringly large the sun is enormous it's like 300,000 times the mass of the earth and you could fit more than a million earths inside of it and that one is also fusion right definitely this fusion happening at the core of the sun yeah and it's sort of just right for us though right like if it was brighter maybe it we wouldn't be a lot or dimmer. Yeah, exactly. If it was a lot brighter,

then the surface of the Earth would be a lot toastyer, and maybe Mars would be a better neighborhood to live in. So it's like 300 times brighter than those red dwarfs that are nearby. But it's only going to last about 10 billion years. So we're halfway through the life of the sun. Oh, wow. So it's about 300 times bigger than the red dwarf, but it'll last much, much less.

Yeah, so it's only about 10 times the mass, but it's going to last a lot less time because if you crank up the temperature, fusion really takes off and starts burning a lot faster. It's very non-linear. You double the mass, you get much hotter temperatures

and you burn through that mass much faster. So here in our solar system, that means we're sort of in the low end of the massive sun scale, right? Our sun is relatively small compared to what's out there. Yes, absolutely. Our sun is not impressive

compared to the most massive stars that are out there. It's not in the population of the smallest stars, the red dwarfs that are very, very common, but it's not an impressive star at all. We still like it, though. It's still our favorite star. It's perfect for us. All right, so let's crack up the mass even more. What happens if you get into thousands of

times the mass of our sun? Well, you can't actually. It turns out that the biggest stars that are out there are only like 100, 150, up to maybe about 200 times the mass of the sun. I see, because what happens after that? What happens after that is that the sun gets really big and really hot, and it starts to burn really strongly at its core, and that fusion generates a lot of radiation, so it blows out the outer layers of the star. So there's sort of an upper limit to how much mass you can cram into a star and have it still be stable. Remember, a star is sort of a balance between gravity that's trying to compact it and fusion that's pushing out, the glowing, the hot energy that's keeping it from compacting. I see. So if you gather more than 200 times the mass of our sun together in like a giant hydrogen cloud,

it wouldn't all crunch together in the middle because by the time it starts to crunch, the middle starts exploding and then that blows everything away. Yeah. And first of all, if you had such a huge cloud, it probably wouldn't collapse into just one star. It's more likely for it to collapse into several smaller stars. But if you somehow arranged like a bunch of really big stars to combine themselves together into something which was two or three hundred times the mass of the sun, it would blow itself apart because the fusion at its core would be so powerful.

All right. Well, let's take the next step then. What's next step after our star? After our star, this serious, which is actually the brightest star in the night sky, and it has two times the mass of our sun. So it's like two scoops of sun. And it's much bigger actually than our sun. It's like eight times the volume.

And even though it's only twice the mass, it's like 25 times brighter than our sun. Hmm. That's a general thing, or is it just this one star? No, in general, as you crank up the mass, the brightness goes up much, much faster. This is the mass luminosity relationship. We talked about another podcast episode. That's what we use, actually, to measure the mass of stars. We look at their brightness. Because as we said before, as you add mass, the temperature increases and then increases really

dramatically, which tips off nuclear fusion, which makes things even brighter. Yeah, in fact, the brightest star in our night sky is one of these two sun stars. Yeah, exactly. That's serious. Are you serious? Surely, you're joking. Stop calling me, surely. All right, so a star that's two times the mass of our sun would only live two and a half billion years. Yeah. Wow. It's burned through his fuel. Wow. All right, what's the next step?

Next step up is Beta Centauri. This thing is 12 times the mass of the sun, and it's about a thousand times as big. So you could take our sun and fit it into this star a thousand times. It's hard to hold that. idea in your mind. Wow. It's only like 10 times more massive, but it creates such a crazy condition of explosions that that sun basically fluffs up, right? Yeah. It's like a big fire. Exactly. It's a huge fire. And that's why it's 20,000 times brighter than our sun. 20,000 times. Wow. That's like taking 20,000 suns and shining it on us. Imagine having 20,000 suns in the sky. Like, that's a hot day. Yeah. Do we need 20,000 SPF? At least. And this is a super awesome star because it's only going to live for 20 million years.

These things, they are fiery, they're impressive, but they do not stick around. What happens after 20 million years? After 20 million years, it goes into its super giant phase. It actually gets much, much bigger. And then eventually it collapses and it's going to form either a neutron star or a black hole, depending exactly on how much mass it has. Wow. 20 million years is not a lot of time, astronomically speaking, right? You wouldn't have enough time to develop life or really, you know, get all your grocery shopping done. No, you wouldn't.

And the other interesting thing is that this is part of a star system that has three stars. You've heard of a binary star system. We have two stars orbiting each other. This one's part of a triple system. So there are two other stars there that are much smaller that will last longer. And you might develop life around one of those, but only if it can survive the cataclysmic end of Beta Centauri. How common are these types of stars? Are we getting into more rare kinds of stars?

These are definitely much more rare. As the mass goes up, the frequency that you'll find these stars drops, not just because it's harder to get a large blob of mass. It's just less likely for it to happen, but also because they don't last very long. Like these red dwarfs, they're going to be around basically forever, right? Trillions of years. The yellow dwarfs were talking about billions of years,

about the lifetime of the universe. Here we're just talking about millions of years, which astronomically speaking is like a blink. So these things, when they do happen, they don't stick around very long, and that, of course, contributes to their rareness. All right, let's get into the king of all or queen of all massive stars. There is one that you can crown as the most massive star. There is, though there is some disagreement.

You know, it's hard to measure these things, as we talked about, especially on the very upper edge. And so different astronomers might say that different stars are the most massive. But there's a couple that are like right at the edge. And the one I think that's super cool is this one called R136A1. This one's 215 times the mass of the sun. 215 serving scoops all put together into one star. Wow.

And I imagine that's really bright. Yeah. This thing is as bright as 9 million suns. Wow. 9 million suns shining all at once. Yeah. And it's so close to this limit of how big a star can be that it's just not going to last very long. It's radiating out so much energy that the fusion.

happening at its core is pushing out the edges of the star. It's losing mass constantly. It's an explosion. It's falling apart. Because at some point it like pushes things out so far that they just escape the gravity. Yeah, exactly. The fusion pressure at the surface is greater than the gravitational hold. So things are getting pushed away from the star. Like you imagine these really, really massive objects in space are going to suck you in, right? This is a star that pushes you away. The solar wind from this star is so strong that it's actually pushing its own skin off. Wow, that's disgusting. But also pretty impressive. Don't be judgmental, man. That's just the way the stars are. And when you say pushing you, you really mean more like prying you, right?

Like if you were there being pushed by the star, it's not like it's pushing you. It's like it's throwing fire at you. Well, both. Like it's a lot of energy for you to absorb. But remember, the solar wind has momentum. That's how we talk about like solar sails, right? They can really capture the momentum of the solar wind. And that's why these things are expanding. That's why they're literally blowing up because the solar wind is literally pushing, not just frying and cooking. There's a lot of momentum that's being imparted, anything that comes close to this thing and actually the outer layers. So it's tearing itself apart. Right. I guess what I mean is it wouldn't feel good to be pushed by that much radiation. No, it would not feel good. I don't recommend

going like solar surfing or anything. Solar sailing. Solar sailing. Solar sailing, yeah. The incredible thing is that this is just one part of an enormous cluster. Like this is maybe the most mass. massive star in the universe, 9 million times brighter than the sun. But actually only recently we figured out that it's one star because it's part of this big blob of stars that together, this huge cluster is called R136, is 10,000 times brighter than just this star. Oh, wow. This most massive star is really like a minor player in an orchestra of stars. Yeah, it's the biggest one.

It's just a huge collection of stars. And this is like the big grandpappy. But together, all those stars outshine this one by 10,000. So it's a crazy object out there. Wow. Is that about as massive as stars can get? What if I have a star that massive and I pump more hydrogen into it? What would happen?

It would blow itself up. As you get it more massive, it's going to increase the temperature. And that's going to increase the rate of fusion, which is going to increase the radiation pressure. And so it's going to tear itself apart. It's going to blow up. It's going to blow up, yeah. somebody actually wrote to me and asked me, like, if you wanted to blow up a star,

what would be your go-to strategy? And, you know, as usual, I thought, is this a supervillain making a plan asking me for physics consulting? But the answer I gave him, I thought was pretty impractical, which was like, just add a lot of mass to the star, that'll blow it up. So if he's somehow capable of injecting 500 times more mass into our sun, for example, that would spell its doom.

Right. Well, I mean, obviously it's a lot, but it doesn't sound like a lot. Yeah. You don't need millions of suns to blow it up. You can just gather a few hundred. Yeah, and it's fascinating. That's why these extremes are really interesting.

It tells you that you can't have an arbitrarily sized star, right? You can't just have an enormous galaxy-sized star. That's why galaxies are filled with stars instead of us having galaxy-sized stars because there's an upper limit. Because stars are not just like blobs of gas floating out in space. There's this push and pull. Gravity is squeezing them down. Fusion is pushing them out. And there's only certain regimes in which those two things are close.

enough to being balanced that the thing can exist for very long at all. Right. But I guess also that's only in the star category. You can have objects that are more massive than two or 300 masses of the sun, right? Yeah, for example, a black hole, right? We have black holes that are billion times the mass of the sun. And we talked about what's the biggest planet you can have to. Yeah, exactly.

Though that's definitional, right? As far as we know, though, there's no physical upper limit on the mass of a black hole. The only limit there is how do you get so much stuff near a black hole so that he can eat it? How does it actually fall in within the lifetime of the universe? Which is why we think the biggest black holes out there are like 5, 10, maybe 15 billion times the mass of the sun. We don't see in the outlet there are a trillion times the mass of the sun. Though theoretically, there's nothing preventing that from happening. But here, even theoretically, you can't build a star that has 500 times the mass of the sun

and expect it to last more than a few hundred thousand years. Right. What if I take like a heavier element? Can I take 500 times the mass of the sun in helium and put that together? Would that give me a star? No, because that would also trigger fusion and that fusion would be even hotter and more energetic. And so you would also dispel the death of the star. But the elements would be heavier. Wouldn't there be more gravitational pressure? Yeah, and more gravitational pressure is exactly what's driving the fusion, right? More gravitational pressure means higher temperatures, which means faster fusion. which means more fusion radiation, which means the death of your star. All right. So there's a limit to stardom.

There is a limit to stardom, exactly. About Tom Cruise, you can't get any bigger than that. Tom Hanks, Tom Cruise, Nicole Kidman, that's it. You collapse into an egotistical black hole after that. A black hole of paparazzi's and tabloids. Exactly. All right. Well, that's the most massive stars.

Now let's get to the question of what's the biggest star? Like if you're standing in front of it, what would be the biggest star that you can see or be in the presence of. So let's get into that. 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, You're like, okay, pull this, and pull 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 IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. 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 12. 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. I had this overwhelming sensation that I had to call it right then. And I just hit call, said, you know, hey, I'm Jacob Schick. I'm the CEO of One Tribe Foundation. And I just wanted to call on and let her know there's a lot of people battling some of the very same things you're battling. And there is help out there. The Good Stuff Podcast, Season 2, takes a deep look into One Tribe Foundation, a nonprofit

fighting suicide in the veteran community. September is National Suicide Prevention Month, so join host Jacob and Ashley Schick as they bring you to the front lines of One Tribe's mission. I was married to a combat army veteran, and he actually took his own mark to suicide. One Tribe saved my life twice. There's a lot of love that flows through this place,

and it's sincere. Now it's a personal mission. Don't have to go to any more funerals, you know. I got blown up on a React mission. I ended up having amputation below the knee of my right leg and a traumatic brain injury because I landed on my... head. Welcome to season two of the Good Stuff. Listen to the Good Stuff podcast on the Iheart radio app, Apple Podcasts, or wherever you get your podcast. All right, we're talking about

the biggest star in the universe, not just here on Earth as a movie star, but in the astronomical sense, what's the largest, right? That's what we're talking about now. Largest. star that you can have. Like, if you were standing in front of it, what's the biggest thing that you could be looking at? What takes up the most space in our universe? I like to imagine, you know, taking a spaceship and going up to the surface of the sun, it would seem like it filled up your whole horizon, right? It would be so vast. It's like an ocean of burning plasma. And then it's awesome to think about like that being dwarfed by something even larger. Right, right. All right. So then let's talk about volume. Like what determines the volume of a star? This is a little bit tricky,

right? Like how you measure the volume of the star and how you even define it is a little bit tricky. Don't suns have a surface that you can measure off of? Like our sun has a surface, right? Pictures of it look like it has an edge. Yeah, but it's sort of like the earth. Like where it is at the atmosphere end? It's not a hard cutoff. It's sort of like drifts off gradually. So you can say, obviously, we have a surface on the earth, but the sun doesn't have a rigid surface the same way the Earth does. It sort of has a gradual drop off in density. Then you get to the outer layers. And so it's hard to know. exactly where to define the size of the star. Right, right.

It's a little fuzzy, but still I feel like, you know, if you look at a picture of the sun that they've taken, it does seem to have like a surface of molten something or a surface of fire after which it's not as defined or you see the blackness of space behind it. And you can also think about like what is the part of the star that's actually glowing, that's giving off light. Maybe you could define the edge of it that way.

And that's actually useful because that's connected to how we know the size of these stars. Like we're going to talk about some really big stars that are super far away. And you might wonder like, well, how do we know this thing is so big? And we can't measure it exactly. Only for like really close up stars can we actually resolve the left side of it and the right side of it and make a measurement directly of how big it is. It only works for stars that are very, very close to us where we can use like parallax. Beyond that, we have to have models that say, oh, if the star is this temperature and has this brightness, then that tells us it must have a certain surface area in order to emit.

that much light, and from that we can deduce the volume of the star. You have to basically sort of guess based on your knowledge of how Sons work. Yeah, we have a model. It was not exactly a guess. It's called nuclear physics, but we have a model for what's going on inside the star that connects the brightness of the star with the mass of the star and the temperature of the star. And from all that, we can estimate what the radius of the star must be. I feel like I just insulted you, Danny. Not just me. It's okay. It's just a whole field of physics. You mean a hypothesis without proof is not a guess?

It's not without proof. We've developed these models and we test them. We look out in the universe and we see, do the stars behave the way we expect? And we can only test them in some cases for closer up stars and the rest of it is extrapolation. But it's not just like, I don't know, let's pick a number. So there are stars that we can measure the size of from here?

Yeah, there's stars that are close enough that we can use parallax to directly measure their size, but not very many. Hmm. All right. Well, the other tricky thing is that the size of a star changes over its life. You know, it grows and then it shrinks. Yeah, exactly. The star, for most of its life is about the same size. It burns happily. It's in that happy place where fusion and gravity are like in balance with each other. But eventually, fusion makes really heavy metals, which collect at the core of the star and increased the gravity. And then eventually the fusion starts happening sort of more on the outer edges of. the star. You only have hydrogen near the outer edges of the star now. And so that's where most of the hydrogen fusion is happening. And that creates more pressure to blow out the star. It makes it get

much, much bigger. Our sun, for example, is going to get to 200 times its current volume when it goes into its red super giant phase. Hmm. Right. It gets so hot that it burns brighter and bigger. Basically, the flame gets bigger. Yeah, exactly. And so it gets really big and fluffy. And like where the Earth is right now is probably going to be pretty close to the radius of the sun when it gets near the end of its life cycle. That's in about five billion years. So you still got time to do a lot of stuff. But that's going to happen to our star and to almost every star out there. All right. So I guess maybe we're really talking about what's the peak volume of stars, right? Like at their biggest, what's the biggest they can get? Exactly. Or like when we look out there currently

in the universe, what are the biggest stars that are around right now? Some of the most of the Most of the ones that are really big are going to be the ones that are about to die because they're in this last stage where they're blowing themselves up before they collapse. All right. Well, let's go down the list. What are some of the ones that are huge? You know, just to get a sense of scale, there's a star, for example, called Gaycrucks, which is like the nearest giant star to the sun.

And it's got only one and a half times the mass of the sun, but the radius of this thing is 120 times the radius of the sun, which makes it. much, much bigger. Oh. And is it a star 1.5 times the mass of Arsson? It's a pretty similar kind of star then. It's a pretty similar kind of star, exactly. And it's in the Southern Cross, actually.

So it's sort of famous. But, you know, it's much bigger. It's only got like another 50% of the mass, but the volume is like 10,000 times bigger. Yeah, that's huge. But is it just because it's in a different stage than our sun? Because Arsson is going to get that big, right? Our stage is also going to get that big.

So, yeah, this one is like all the ones on our biggest stars list is near the end of its life. Oh, I see. These are like peak, peak size. Yeah, exactly. This is when their stars are really reaching like the peak of their career, you know, when they're the biggest they're ever going to be. Right. And so the one we can see right now is this one called Gay Krocks, which is 100 times the size of our son. That's huge.

Yeah, it's radius is about 100 times, right? Yeah. Which means the volume is 100 cubed. Right, right. So it's huge. If our son was sitting next to it, it would look like 1%. That's big. Yeah, exactly.

The ratio between the Earth and our sun is about the same as our sun and this star. So this thing is just enormous. Wow. All right. And so you can see that in the night sky. If you go out at night and look up, you can see this. Yeah, exactly. If you're in the southern hemisphere and you can see the Southern Cross, then yes, you can

see this enormous star. All right. Well, what's the next one on the list? Next one on the list is the pistol star. This one is 25 times the mass. really substantially bigger, but it's got 300 times the radius, right? And remember the volume goes up by radius cubed. So you double the radius, you're going up in volume by a factor eight. And so this one's like three times the radius of Gacrux, which means it's like almost

30 times the volume of that previous star. Wow. At that size, would that fit, for example, in our solar system? Or would it take up the whole solar system? That would not fit in our solar system very comfortably, right? It would go out past the radius of the Earth. I think Jupiter and Saturn would still survive, but it would not be good for us. Like, you would not want to put this star in our solar system. Too big. It's too big. And you can't even see this star by eye. It's super big. It's super bright, but it's actually close to the center of the galaxy where there's a lot of gas and dust going on. So you can't actually see it with the naked eye. It's hidden. Yeah, it's hidden from us by all this interstellar dust.

And what's it called a blue hyper-giant? What does that mean? Well, blue just tells you the kind of light that it's emitting, and a hyper-giant is just the stage of life that it's in. All these stars, when they're done with the main sequence, and they're about to blow themselves out. They become giants or super-gions or hyper-gions depending on, you know, the radius. All right. Well, what else do we know is out there? What's the next biggest star? The next one is Roe Cassiopeia. It's a yellow hyper-giant. This one is 500 times the radius of the sun. Wow. So this is kind of what would happen to our star, but like a little bigger star, eventually it would grow to this big. This one has 40 times the mass of our sun. Our star is never going to get this big. And because it's so massive, it also makes it more rare.

Like we don't know very many of these yellow hyper giant stars in the whole galaxy. There's only like 15 of them that have ever been seen. Wow. And this one is definitely bigger than our solar system. This one would definitely like eat Earth and Mars, but actually wouldn't even get out to do. Jupiter. Jupiter is much further out than all of the other planets because the asteroid belt in between. But still, that's huge, right? It's huge. I mean, it's like 500 times the radius of our sun. Yeah. I mean, if you look at the solar system, for example, zoomed out so you can see all the planets, even the huge sun looks really, really small. Now, replace that with an enormous star that's like the size of the radius of Mars. The whole solar system would look totally different.

Right, right. And from here on Earth, if our sun was 500 times bigger, you know, we would see it take up the entire sky and then eventually eat us up. Yeah, that would be really crazy. Imagine living on a planet where the sun took up the entire sky. Toasty. All right. Now, what's the next biggest story that we can see? Next is one that's pretty famous. It's actually Beetlejuice. Beetlejuice is about a thousand times the radius of the sun. Like, it just totally dwarfs our entire solar system. This one would even eat up Jupiter if you put it in the center of the solar system. Interesting.

And so again, it's a star that's kind of at its peak. It's like it's burning really brightly right now. Yeah, and actually this one's quite interesting recently because it's been dimming. Like remember, Beetlejuice got dimmed all of a sudden in a way nobody understood. And people thought, is it going to go supernova? Is it about to blow? Then people thought maybe it's just a big blob of dust that passed in front of Beetlejuice. And other people thought maybe it's an alien superstructure.

We really didn't understand it. Maybe this is like a variable star that's like compressing and then glowing, compressing and glowing. We didn't really understand it. But this is definitely a much bigger star than our sun. Wow. A thousand times the size of our sun. That would be huge, yeah, if you're sitting in front of it. Yeah.

And so a thousand times the radius of the sun, right, means a thousand cubed of the volume. And so that's a billion times the volume of the sun. I remember Ty was like, I wonder if there are stars out there that are like a million times the volume of the sun. We're like, here's one that fits a billion suns inside of it. Yeah, that's, that's wild. Well, I hope we blew your mind, Ty. All right. So then let's maybe skip a little bit ahead to what is the biggest star that we know about,

like in terms of size that you can see in the night sky. What is the biggest one that you can see? The biggest one out there right now, the current champion, is one called Stevenson 218. This one has more than 2,000 times the radius of our sun. Wow, 2,000 times. bigger, which means it's like, you know, a bazillion times more volume. Yeah, exactly. It's like more than 16 billion suns could fit inside this thing.

If you drop the sun into this thing, you wouldn't even notice it. Wow. And how much brighter is it? It's a half million times brighter. So you put half a million suns together and you get the brightness of this thing. 500,000 suns in one place. That's crazy. In one place. Yeah. It's just, it's taking up so much space. It's incredible. Like, if you try to fly around this thing in a spaceship, it would take you like nine hours at light speed just to do one orbit around this star. Wow, that's crazy. It takes hours for the light just to leave this star.

Exactly. If you're a photon generated at the heart of this thing, you're not getting out there for a while. Wow. All right. So that is the biggest star that we can see. It's thousands of times bigger than our sun, bazillion times. Bazillion is that the technical term? bigger in volume than our star, and it's half a million times brighter.

It's really impressive. It definitely deserves some kind of prize. And you can see it in the night sky? It's out there in the night sky. It's near this cluster called Stevenson 2, which is why it's called Stevenson 218. And you can't see it by eye. It's actually discovered in around 1990 by astronomers using infrared telescopes. Wow, that's wild. That's huge. So you can't see it because it's so far away? Yeah, this thing is like 20,000.

light years from Earth. So remember that the brightness of a star falls with like the distance squared. And so if you're twice as far away, it's a core of the brightness. And so this one, we're 20,000 light years away, which is why it's apparently so dimmed to the naked eye. But I guess if you have a telescope, you can see it and you can sort of model its size. You can model its size by understanding its luminosity and its temperature. And then we can do these calculations, but we definitely can't measure it directly. And that's a shame because, man, I would love to see this thing close up, like, what does the surface of this thing look like? Yeah, what would it look like? Is it a different color or is it just a big bright yellow ball? Well, it's a red super giant, so probably

would be mostly red. But yeah, you know, if you look at pictures of the sun close up, you notice that there are a lot of like hot spots and cold spots. There's like a lot of stuff going on. So I think you'd see the same thing, but we've never seen one of these things super close up. It would be an awesome opportunity to learn more about how a star gets really big and what it looks like at the end of its life cycle if we could, but you know, it's so far away. Right. And what kind of star is this? Is it like our star, but you pump more hydrogen into it? Or is it something fundamentally different? No, it's just like a bigger serving of hydrogen. It's just got a lot more mass than our star. Like we don't have a precise number for how much mass it has. It's not always easy to measure for

these really, really big, very bright stars. But it just started out with a bigger helping. And that's why it ended up a much bigger star. And then you wait sort of for the end of its life cycle. It's like a really massive star also at the peak of its size. Wow. It's hot stuff. It's hot stuff, exactly. All right, so we covered the most voluminous star and also the most

massive star. So the most massive star is R136A1, which is 200 times the mass of our sun and the most voluminous, the biggest star is about 2,000 times the size of our sun. Yeah, 2,000 times the radius and then billions of times the volume.

All right. And that basically makes me feel small, Daniel. That's the goal of the podcast, exactly, to think about the size of the stuff that's out there in the universe. And remember that we're pretty tiny compared to the enormous, powerful forces creating these objects out there. Yeah, because they make our star look tiny, and we're super tiny compared to our sun. Yeah, we're even super tiny compared to our Earth, which is super tiny compared to our sun, which turns out to be a pipsqueak in the universe. Well, it's pretty amazing to sort of think about it because the recipe for all these things. stars is the same, you know, it's just add hydrogen. But, you know, you get all this huge variation in like what's happening and the processes and the volume and the mass. It's a pretty complex

and impressive universe. Yeah, I do like the idea of a star having a recipe, which is one ingredient and one step, right? But no more, right? Like, if you get it off by a little bit, it becomes a totally different star. That's true. If you get it off by a factor of 500, then you no longer get a star. But that's also true of cookies. You know, you put in 500 times too much sugar. They're not really cookies anymore. Right. Or 500 times more chocolate chips. You just get a chocolate chip. Exactly. That's just a recipe for a chocolate chip. It sounds like a star of a recipe. I have strong opinions, but I would taste it. You would just taste chocolate. It's like, oh, yeah, that's an interesting recipe. A chunk of chocolate with little tiny cookies embedded in it.

A cookie chip, yeah. All right. Well, we hope you enjoyed that and made you think about the bright and the amazing things that are shining out there in the night sky. And remember that however big you think things are, they're actually much more vast than you could ever possibly imagine. All right. We hope you enjoyed that. Thanks for joining us. See you 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. 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. From tips for healthy living to the latest medical breakthroughs, WebMD's Health Discovered podcast keeps you up to date on today's most important health issues through in-depth conversations with experts from the healthcare community, WebMD reveals how today's health news will impact your life tomorrow. It's not that people don't know that exercise is healthy. It's just that people don't know why it's healthy. And we're struggling to try to help people help themselves and each other. Listen to WebMD Health Discovered on the IHeart Radio app 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 two, takes a deep look into One Tribe Foundation, a nonprofit fighting suicide in the veteran community. September is National Suicide Prevention Month, so join host 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

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