When will the Sun explode?

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Speaker 1: All the stars in the universe are constantly exploding nuclear bombs. Um, that's a little frightening. We'll go out there and warm your toes on the you know, the thermonuclear fire of a huge bomb that's constantly exploding. That sounds it's like a contain and continual explosion. Yeah, you want to see a nuclear bomb go off, Go outside and look at the sun. I mean, not directly yourself. You just made this advice. The advice. Yeah, we'll ask them to edit it up. Hello, I'm Jorge and I'm Daniel, and this is our show. Daniel and Jorge explained the universe. Explain the entire universe, especially all the stars inside of it. Now, I noticed, Jorge, every time you introduce your our show, you're about to say R and Daniel explaining the universe, and then you have to correct yourself and you're like, no, actually, we're still bitter about that. You know. My real job, you know, is as a particle of assist and I have five thousand collaborators. And when we write a paper, we put everybody's name on the paper. And the policy has put everybody's name alphabetical by last name, regardless of who contributed more or less or whatever. Somebody decided they didn't want to have the argument, let's just make it alphabetical. And what that means that there's some grad student who's first author on like every paper. Wow, it's like him or her, and it's sort of makes some famous and also sort of infamous because people grumble about it. No pressure, no pressure. That's right in the Glaring Spotlight. But you know, today's episode actually relates to that, to Glaring Spotlights, because today we're talking about something very close to home. We're talking about how long the sun is going to live? How long do we have before it burns out or explodes or snuffs out? How many more projects can Daniel and Jorge or Jorge and Daniel do arguing about order until life on Earth is extinguished because the star is gone. Do you have time to clean out your garage or do that thing you've always wanted to do? Right? That's that sequel to We Have No Idea, our book now available from Penguin Random Pass. That's right. So if you're currently procrastinating doing something you should do, then you're actually gonna learn something today about how much time you have left to procrastinate right, so, um, yeah, let's let's jump in for we as usual, asked people on the street how long they thought that the sun would keep burning until the question is, how long do you think the sun will keep burning? Play along at home, think of your answer, and then listen to these random on the street interviews. How long do you think our son is going to continue to burn for? How long? I think a few billion years? I don't know. Millions, No, not millions, sorry, probably a long time. I hope a long time. Like, doesn't this affect your plans? Come on, you should know this al right? Well, I guess the first thing is that nobody seemed really concerned. That's right, nobody's rushing home to finish up something before the sun snuffs out or explodes that like what, the sun is gonna stop burning? At some point? Everyone seemed to know about the idea that the sun won't shine forever. Oh that's a good point. I never even considered that that I would be the one informing people by asking the question that the sun was not gonna last forever? Oh my god, what what are you saying? I know everybody seems to know that already, but maybe nobody seemed concerned because everybody's answers were very far off in the future. Nobody said, I don't know ten years years. Everybody's like random big number. Everybody feels like it's just so of far off in the future, it doesn't matter. Well, let's maybe take a step back, like how do stars even inform? Right? Like I imagine out in space there's stuff like dust and little bits of rock, and at some point the gravity pulls them together, like there's some nearby each other until they clumped together, and first it's a giant rock, and then it's an even bigger rock, and then it just gets more massive, and at some point what happens. Yeah, but it's not mostly rock. Stars are mostly made out of gas, mostly out of hydrogen. So in the Big Bang, most of the stuff that was formed after the Big Bang was hydrogen, a little bit helium and a few heavier elements, but mostly you just have huge clouds of gas formed in the early universe, and then gravity takes over and gravity slowly pulls those things together, as you said, and accumulates these gas clouds, and then those gas clouds get pulled together by gravity and they get squeezed together more and more until it gets denser and denser, and eventually it gets squeezed together by gravity enough that it starts to burn. And by burn, I mean fuse. You have like nuclear bombs going off because of the pressure inside these big clumps of hydrogen. Right, what do you mean they get dense and like just more and more hydrogen atoms just kind of bunch up because they're all attracted to each other by gravity. Yeah, it's kind of like a runaway process. I mean, if you had a perfectly smooth universe filled with hydrogen atoms, then no one would want to go anywhere because you'd be tugged in every direction at the same strength. Everybody would be attracted to everybody else equally. Yeah, that sounds like a good party, right, universe party, we're all attracted to each other. Yeah, party, that's right. Hey, you know the analogy works because we're gonna talk about fusion and fusion and things are going to get hot. You don't want your relationship to go supernova later on. In relationship advice from an astrophysicist, Yeah, yeah, today we're just knocking out that. To that advice, children go out and look at the sun. People have explosive relationships. This is our last episode, by the way, guys, right, so um, But there were little areas in the universe early on they were a little denser than others, and that's just because of quantum fluctuations. And then those areas were heavier because there's a little bit more stuff, you're more heavier, you have more gravitational pull than anywhere else. So then you start to attract more stuff, and the heavier you get, the denser region becomes, the more gravity it has, the stronger its ability to pull more stuff in. And then it gets heavier and heavier, and it's a runaway process where pretty soon it's accumulating stuff faster and faster. So you can imagine like at some point a giant ball of really compressed gas, right, Like maybe at the edges it's not as compressed, but in the middle, it's just everything is trying to push it together, right, But it doesn't immediately fuse because hydrogen atoms are also repelling each other at the same time, right, Like they're attracted by gravity, but they're repelling each other by other forces. That's right. Fusion is not easy to pull off. I mean, we're trying to do it in experiments all the time here on Earth. Like it's like trying to squeeze too many together they are on the same polarity, right, yeah, or trying to make two kids share one ice cream or something. Not a good idea. But so it's the repelling there have been attracted by gravity, repelling by electromagenic forces. But at some point, if you get them close enough, then another fource kicks in, right, and that's what kind of fuses them together. Is that true? Yeah? And that's when you access the strong nuclear force, and that fuses them together, and the strong nuclear force very strong then therefore its name. And when you do that, you release a huge amount of energy. And so that's what all of the energy is coming from, is just these hydrogen atoms fusing together. That's right. Almost all the light from all the stars in the universe is from hydrogen fusing together and creating all that energy and shooting it out into space. But is it like a kind of like a chain reaction, like you know, like a nuclear bomb, like one explosion causes the next explosion. Is that what's happening inside a star or is it just just the pressure just kind of makes like popcorn just makes all these kernels pop pop up. So on Earth, it's a chain reaction you're thinking of like fission. Fission is the opposite process, and you break in nucleus up and it sprays out and stuff. I'm here. You just have a huge blob of hydrogen in the core and it's being squeezed by the outside and everything around it, and it gets really hot. And you know that's true of every object, like even the Earth. What's at the center of the Earth. It's not cold at the center of the Earth. It's hot, and it's hot for lots of reasons, but one major reason is that it's being squeezed by gravity. All that rock on the center of the Earth is being squeezed by all the rock on the outside, and it gets turned into lava. Right. Why is lava hot Because it's been squeezed by gravity. Gravity is pretty powerful if you give it enough time and stuff. So are cloud of hydrogen. It just kind of suddenly ignites or is it kind of like burns begins to burn slowly, like as the star go like or is it is it kind of a long process? No? I think it ignites pretty quickly once it gets going um and it and what happens depends on how big it is. Um So, if you have a huge blob of gas, right and it forms an enormous ball of of of hydrogen, then it can burn really brightly and not for very long. If it's smaller, then it doesn't get to be big enough to burn like you know, like the Earth or Jupiter or something. Jupiter is like a star that never got started because it just wasn't big enough for the core to start burning. Oh, you need more stuff to m basically weigh down and squeeze the middle. That's right. Yeah, the core of Jupiter is not being squeezed enough. I mean, it's massive gravitational pressure. You would not like it it. Do not recommend it as a destination for your occasion, but against yeah, that's right. There are some common sense warnings on this show. But it's not hot enough to start nuclear fusion. Okay, so then things say squeeze and you got a sun. Suddenly you have this big ball of gas that's burning in the middle. That's right, it's burning through nuclear fusion. It's turning hydrogen into helium. Okay, cool, And I want to talk a little bit more about that. But first a quick break. Yeah, that's how stars are born, um, not just in Hollywood and they and then it just keeps burning for a long time, right, until all the hydrogen turns into helium. Yeah, that's exactly right. You have fuel and you burn that fuel, and when you're done burning that fuel, you're done. But the interesting thing is that the output of fusion is helium. Right. But and so what happens is that you accumulate helium at the core of these stars and then if it keeps going, if it gets big enough, then you can start to fuse helium. Oh and then that's um, it's like it it goes into secondary fuel burning mode. Yeah, exactly, burning helium because you confuse helium into the element with number four, which I embarrassingly can't even remember, is that lithium. Okay, so we're talking about the what happens to the star, and that's at some point it makes it turns all the hydrogen into helium and eventually into iron. And that's kind of when that's what kind of when a supernova happens, right, Yeah, Well, it doesn't necessarily happen. Have to be a supernova depends on the mass of the star and so let's talk just to be specific about a star like ours, you know, the sun, and any any object that's like about up to eight times the mass of the Sun is going to have an experience like our sun. And so what happens. It starts to burn hydrogen, like we said, and then the hydrogen gets and the core gets burned up and you get helium, and then you start to burn the hydrogen on the shell, and then the star starts to grow. It gets bigger, like physically larger in space. And the reason is that you're now burning the hydrogen on the outside and that the burning there is pushing stuff out. It's like the radiation pressure is making it grow. So the sun will keep burning and then it will expand and it will cool, so it'll start to get larger and it will turn into a red giant. So giant meaning gets bigger and red because it changes color because the color is related to the temperature, right, like, the cooler it is the right like it's kind of counterintuitive. The colder it is the star is the redder it is. But then the hotter it is, the bluer it looks, right, Yeah, And that's related to the wave length of those lights of that light. Yeah. Yeah, Like if you could found you press fast forward on life on Earth, you would see the Sun is this yellow dot. But eventually you'll see it grow and grow redder and then grow and eventually will take over our entire sky. And at some point we'll just snuff us out. That's right. Eventually we will be in the sun. Earth. Earth will just get like eaten up by the Sun. Yeah, exactly. But that's bill again, billions of years in the future. It's like three billion years in the future. Three billion years. Yeah, and so before but before we even get snuffed up, you know, it'll get pretty hot and we wouldn't want to be around anyway. So first the oceans boil and then we get snuffed up. Yeah, and then that's that's like the last phase before the Sun dies. And then it's mostly used of its fuel, and you know, it's like a fire. You use of the fuel and then the fire goes out. So everything turned to iron. Maybe it's not every star that can make iron, depends on the size of it. Mostly iron is made in much bigger stars. So our star is not big enough to make iron, so will probably make helium and a little bit of lithium and a few other things. Oh, I see. So some stars are bigger, so they have more pressure so they can cook iron, but but ours cannot exactly. Ours is not by far one of the biggest stars in the universe. It's relatively modest. Yeah, And and then when it burns off all the hydrogen sort of on the outside, then it'll go out, and what we'll left be left with is something they call a white dwarf, which is basically just meaning a big cool blob, something that's not burning anymore of what um. It's just sort of the leftover stuff. You know, you have enough elements there to sit there there. It's hot and so it's sort of glowing, but it's not actually burning anymore. And you'll have some helium and maybe some lithium and just be like a dense blob, but it won't be bright the same way, and it will cool and eventually become a black dwarf, which means basically a big lump of rock, like just a giant meter right, yeah, though mostly made of like frozen helium. Frozen helium for real. Yeah, because mostly what mostly what the Sun is is burning hydrogen into helium. And again some of that helium will get burned into heavier stuff, but most of it won't, I think. And so this is going to be like a giant ice ball the size of what. Oh, you'll be small, you'll be smaller than the current Sun. It's just the core, Yeah, just the core is left over because all the other stuff is blown out when it turned into a red giant. But yeah, some significant fraction of the mass of the Sun is going to end up left over as a white dwarf and then a black dwarf. Yeah, exactly. And you know that has a future. It could be that that um then gets clustered together later on and becomes part of a new star. You know a lot of the stuff that's in um in our star and in the Earth used to be inside of a star. And so you know, everything that we're that we're made out of is a remnant from a star that died. So if it wasn't for stars and these fusion furnaces making the heavier elements, then there wouldn't be anything else to make stuff out of. It would all just be hyde in the helium. And so it's gravity squeezing this stuff together over billions of years that makes the heavier elements, and mostly in the bigger stars that you get up to like iron. You know, the bigger stars can do more exciting stuff. Like our son is not going to go supernova, is just not big enough. But a bigger star could have enough mass that it collapses and it pushes it together and it can create a supernova and then two weird things, either a black hole or a neutron star, which I think is one of the weirdest things in the universe. So it's more of an implosion than an explosion. Actually, yeah, yeah, yeah, it's pretty crazy stuff. So you're saying that's when that's when the heavier elements can eat, right, yeah, in some of these supernovas, because you have heavy stuff flying around um and and it collides and it forms even heavier stuff. Yeah. And then but the heaviest stuff, like we were saying earlier, gold and all that stuff gets formed when the when two of those remnants collide, like say you have one really massive star lives its whole life, has a great time, blows up, turns into a neutron star, and another one does the same thing, and then the two neutron stars are orbiting each other and eventually, because they're so massive, they pull each other together and they collapse and they collide into each other, and it's in that collision that you can form the really heaviest stuff. So all the super heavy metals in the universe are made when neutron stars die, and that's why they're so rarities that you need these crazy events just to make gold and titanium and all these elements. Right, yeah, that's right. But it's crazy that we have that stuff on Earth yet, right, I know, we have it here on Earth, and it's like the leftovers these incredible cosmic events that happened billions of years ago and then got sprayed out into the universe and with enough time for them to like have a whole new life. You know. I love that everything in the universe is getting recycled, right, Like our solar system didn't even start forming until you know, five billion years ago, which is nine billion years into the party. Right, Yeah, let's talk about that, But first let's take a quick break. Right now, is when the sun is like looking over the hot sexy sun in the next solar system and looking corvette, right, yeah, it's wondering, like do I look like a big fat red giant. Tell me I still look small like a nice little yellow dwarf. Yeah, exactly. And one thing that I think is really interesting is that the smallerest star is the longer it lives. The bigger star is the shorter it lives. And the first stars in the universe were massive, they were incredible, and so they didn't live for very long. Like those first stars we talked about, none of those are around anymore. None of the stars that are in the universe now our first generation stars. They're all second, third, fourth generation, that kind of stuff. All the stars were seeing the night sky in like the pictures of galaxy. They're all Um. None of those are among the first stars that were formed about a hundred million years that's the big Bang. Yeah, it's only recently people scientists even saw the light from those first stars. It's really hard to see. Um. You have to use the infrared because the universe was so dense back then. But yeah, our star is made out of leftover bits from other stars earlier that burned and exploded and wow and recombined. Right, And eventually you're saying, our big ice ball of the Sun is going to recombine with something else maybe and for but you can't do this forever, you know, Like there's a limited amount of hydrogen and you need hydrogen to to have these reactions to start. Eventually things get yeah, things get denser and denser, and you're run out of fuel. So like think about the Milky Way galaxy. It's got enormous blobs of of hydrogen gas. Still it's still making stars, but eventually it's going to run out, and then it's gonna stop making stars. And those stars are going to burn for a while, but they're not going to burn forever. So eventually everything's going to be like iron and heavier metals. Yeah, yeah, and then things will get dark. Things are going to get rocky. Things are rocky, that's right. But some of these stars, some of these stars are gonna burn a long time. Like there are stars that have lifetimes of trillions of years, but that's not up us. So in five billion years, we've got to figure something out. Yeah, we have. We have to figure out how to find get to another star. And we got less than you know, three ish billion years to figure that out. Oh man, so we have to jump to another star that that is burning and or um just learn to live in the dark kind of right, Well, you know, fusion is not impossible. You know, we can copy the energy source of the stars, um if if we we don't necessarily necessarily need a star, right, we could power ourselves through our own controlled fusion if we if we could figure that out. But do we have enough hydrogen or water to last as that long? Yeah? I mean the Sun is massively inefficient, right, Like most of the energy the Sun gets thrown off into space and then and not even used. So we wouldn't need anything nearly as big as the Sun to power human civilization. So we could just go out there grab some of that hydrogen floating around, or go to Jupiter maybe grab all that hydrogen, create our little mini sun here. Yeah. Or you know, if you're living out in space, you don't have to worry about pollution, like, so you can just do fission, which is much easier, and there's plenty of that stuff floating around, and you know, you get radioactive waste, you're just jettison. You're already in space, so who cares? Right, Interesting because you used to think the ocean was too big and you could just polluted forever without consequences. We know that's not true, but it is true of the universe that you're never going to fill the universe with garbage. Yeah, you think in a billion years people gonna say, I can't believe they filled space with junk. Man, you're responsible. You're gonna be like, don't throw don't throw plastic bags out into space because the space dolphins are gonna it kills all those cute space and space dolphins choking on your cosmic ways. Why is that funny, worry? I don't think that's funny at all, and I think you're a jerk for laughing. Cool. Well, that's that's kind of interesting, that the idea that maybe we will never leave our solar system and we will just figure out how to make our own little minisans to keep us warm. Yeah. Absolutely, I think I think we could do that. Until then, I guess, um, we're sunscreen that's right, And don't worry too much about the sun burning out. We have bigger problems to figure out than whether the sun is going to explode. You've got lots of time to work on that problem. Do you have a question you wish we would cover, Send it to us. We'd love to hear from you. You can find us on Facebook, Twitter, and Instagram at Daniel and Jorge One Word, or email us to feedback at Daniel and Jorge dot com