What would happen if the sun became a black hole?

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Speaker 1: Horror. Can I ask you a hypothetical question? I'm not a big fan of speculation. Well, my question is, what if you liked hypothetical questions? Isn't that a hypothetical question in itself? That's right, exactly, it's a hypo hypothetical question. In that case, I guess I would be very happy right now if I like hypothetical questions. In that universe in which you do like hypothetical questions, I've got one for you, all right, I am hypothetically excited. So do you worry about dramatic ways that the world might hypothetically end? I think I worry about any kind of way that the world might end, both the dramatic and the documentary. You mean in the actually hurtling down the road from to us from the future sort of imminent disasters that we're ignoring mostly because the are inconvenient. Well, what do you mean by dramatic? Like A like a like if the world turned into a giant banana or something that would be dramatic. But I hadn't mind things like, you know, getting zapped by an alien ray, or maybe the whole planet falling into a wormhole, or maybe getting smashed into some rogue asteroid or comment. Oh man, well, I wasn't worried before, but I am now. Well, be sure these are just hypothetical questions, and so all your worries are also hypothetical. I am hypothetically terrified. Well, let me hypothetically reassure you you probably should worry about all that stuff. Hi. I'm Daniel. I'm a particle physicist. And I'm Jorge. I'm a physical cartoonist and the creator of PhD Comms. And this is our podcast, Daniel and Jorge Explain the Universe, a production of My Heart Radio which we try to take you on a trip out into the universe to explore all of the amazing and incredible and potentially universe and earth ending things that can happen. That's right. We explore the real, we explore the conceptual, We explore the hypothetical, the universe in which Daniel starts the podcast instead of Joge. I wonder if people are a little bit freaked up by that. Listeners, you are in that universe. This is this is a hypothetical podcast right now. Now, we love to talk about things that happened in the universe, Things we understand, things we don't understand, but we've noticed in our emails that we've been getting a lot of hypothetical questions like what would happen if? And so today on the podcast, we'll be talking about one very dramatic question that people have been writing in about today's topic is what would happen if the Sun became a black hole? We need some dramatic music there. Not a white hole, not a rose hole, not something else entirely, but the sun became a black hole. And I think this is a fascinating question because I think people are intrigued by the concept of black holes, but they also find them mysterious and dangerous, you know, And so they're dangerous. I think the blackness of it, and you know, the mystery of it makes it a little scary. Yeah, And the the idea that, you know, we're comfortable here on Earth, but we live in a tiny little shell of gas on the crust, you know, on this cool crust floating above Magna, in a crazy, dramatic, powerful universe that could snuff us out in a moment without even noticing or caring. And so I think maybe this question reflects people's like feeling that our life on this planet is precarious, right, that there's things out there that are incredibly powerful and dangerous and uh, you know, and they wonder like could these things happen to us? Are most of the questions we get hypothetically about, uh, the end of the world and things like this. No, No, most of them are, hey, can you explain this? Or you said this on the podcast and I didn't understand, um, And I'm happy to answer those questions. But sometimes they are a bit more dramatic, and hey, maybe these are just questions from script writers working out their ideas, you know, um, and it's so awesome send us your ideas. We love to dig into them. But this one is not a crazy question, right, because I think maybe a lot of people know about black holes, and maybe a lot of people have heard that black holes come from stars, right from suns, that's right, Yeah, I mean the end a black hole is just a really a dense clump of mass, dense enough so that even light cannot escape. And you know, stars are also dense clumps of mass, and you're right, end point of a life of some stars is a black hole. And so I wouldn't say it's not a crazy question, but it's it's not a super crazy question. Yeah, absolutely, there's some some reason to that. We'll dig into that. But before before we do, I thought, let's see if this is something people wonder about. If this people worry about, what do people think would happen if the sun became a black hole? And so I walked around on the streets and these questions. I did not ask of people that you see Irvine, because I was out of town for the summer. But it's a rather international crowd. Folks in Heathrow Airport, folks on the streets, important Portugal folks anywhere. I found them speaking English, and we're willing to answer questions. Are you serious? Really? Yes, absolutely you were. This is our our international plot. That's right. I'm probably breaking all sorts of international laws about recording people. But you know, for you listen release for you'll hear a variety of accents and a variety of ideas. Awesome, So think about it for a second. Well, what do you think would happen if the sun, if our sun, our lovely, bright, beautiful sun, became a black hole? What do you think would happen? Here's what be had to say. Well, I guess we would suck in. We would be sucked in if you used it will be really dark outside. Then after that we can improve where lights some sense, we can't solve the problem. Solve that problem, however, Chetska is going to be the bigger problem. The Earth will whenish in the black hall. But this is not an option, I think, because no, I have no idea. A lot would happen, although we probably wouldn't know about it for eight minutes. We're far too close to be in a stable or with a black hole. Even if this of one solar mass, we would disappear into the into the Sun. That would be very difficult for farmers. I think the Sun would go through various phases before that, of its its core helium expanding or something changing gravitational forces. So I think by the time the Sun became a black hole, we would be either well fried or well suffocated or something. All right, not a lot of sunny answers or optimistic. A lot of a lot of bad things happened here, and people nobody thought it would be good news. Right, Nobody said yes, that sounds awesome. Finally my plan has come to fruition. No no evil villains out there, planning to make this happen. Um. There's sort of two categories of answers. I thought, like one is people thought, well, that's just the end, because there's a black hole nearby. We're getting sucked in, right an The other one because that's what black holes do. They suck. That's what they do. Black holes suck. Um. And the other category is, you know, well, if the black the sun becomes a black hole, then it's no longer a sun, and we sort of rely on the sun being a sun providing light and heat, and so that would also kind of suck in a different way. I like the person who said it would be bad news for farmers exactly, like like just farmers. Everyone else would be cool with it, but farmers they won't get that, you know, farmers tank. Yeah. Well, you know that answer came from a guy who runs a farm in Portugal, and so maybe that was on the forefront of his mind. Is that possible? Could our son become a black hole? And you know, there we can give a pretty definitive answer, right there is almost no universe in which our son becomes a black hole. And that might be surprised or farmers everywhere or relie you can hear Jorge stopping to pack his emergency go bag. No, it's not something that power down. Hey, I didn't get an invite to your emergency spaceship. Why is that you powered the thing up? You're packing it, and you had your own I thought, oh, man, awkward, I thought you had. You should have talked about this. It's kind of embarrassing. Some stars become a black hole, and the basic idea is gotta have enough mass, right, you don't have enough mass to create enough gravity to pull the thing together to make a black hole, then you just get sort of a dense blob of stuff. Anything above like six or eight, maybe ten masses of our sun solar masses can become a black hole. Um, stars that are smaller than that don't have enough gravity to squeeze things together to become a black hole. That doesn't sound like a very safe margin of error, you know what I mean? Like, if our son was just you know, a couple of times bigger, it would totally pretty possible. I don't know, the Sun is pretty big, dude, So we're talking about a huge amount of stuff you need to add, Like ten solar masses is not just like the change in your pockets. Right, it's a huge amount of stuff, I guess. I mean, how confident are you on that map? You know, is it like it would never be able to turn into a black hole, or is it like not likely to get turned into a black or he starts to power up his spaceship again, I can hear it. Know, we're fairly certain that the Sun is not going to become a black hole. But that doesn't mean that, like it's all cool, right the Sun. We did talked about this on a whole other podcast. The Sun is going to end its life when it's done with its fusion cycle. And when that and before that happens, it's going to expand and get huge, and the radius of the Sun will be larger than the orbit of the Earth, meaning that the Earth will be inside the Sun. Right, And so even though the Sun is not going to end its life as a black hole, that doesn't mean that when the Sun ends its life, will all still be happily here on Earth, farming in Portugal. We won't even need to see this black yeah, exactly if it, if it could turn into a black hole, we wouldn't even survive see it. Yes, So it doesn't actually even really matter if the Sun becomes a black hole or a white dwarf, which is much more likely, because we will be toast either way, unless, of course, we all cram onto Jorge Special Spaceship and we can just watch the party from the safety of Pluto. How big is this big ship anywhere? Now you went ahead and told everyone, Daniel, thanks a lot. You know, only our listeners, which of course are the most intelligent, best looking, privileged people on Earth. That's right. If you had to self select, you have to select the population of people to say, from humanity obviously, now boarding Zone A for Jorge Spaceship, our premium listeners, Daniel, Jorge explain the universe. Oh sorry, you haven't listened to all of our podcast episodes. Oh but you know, some people might be wondering about about what I said there because another podcast we said that you could take anything and make it a black hole, right, like and take a baseball and you make it small enough, you can make it a black hole. And that's true, right. All you need is a certain density of stuff. Um, but for stars you do need a certain density. But to get to that density you need a minimum mass because there's there are things that are preventing stars from just falling in. Right. The reason everything like your pillow and your hamster doesn't don't become black holes is because there are other forces preventing them from becoming super dense. And so for stars to have enough gravity to overcome the barriers to that density, they have to have a certain mass. I think what you're saying is that technically the Sun could become a black hole, right, Like, if the hand of God reached out and grabbed the Sun and squished it, it could become a black hole. But naturally, left to its own devices, our sun can't won't ever turn into black That's right. Exactly, if the hand we got reached out and squeezed all the mass in the Sun down to a ball about three kilometers wide or smaller, then it would be dense enough to be a black hole. But there's physics that prevent that from happening, right, Squeezing that stuff down would take a force that gravity can't do, and so gravity not being the hand of God, can't turn this mass into a black hole. But wait, into a ball three kilometers white, But then how big would the hole be? Would the whole bet three kilometers why you mean like I mean, like theon the event horizon life. If you've got all the mass of the Sun into a sphere three kilometers wide or less than the black hole, the event horizon would be three kilometers, right, And again, we don't know what's going on inside the event horizon of a black hole. We don't know if all that stuff is squeezed in at a little point at the center of singularity or sort of quantum fuzzed out, or if it's you know, distributing its some sort of weird pattern. We don't know, and actually doesn't even really matter um from a gravitational point of view, And that's the point we're gonna talk about later. If you're on the outside of a sphere, then the only thing that matters to affect how much gravity there is is just how much stuff there is in the inside of that sphere. Like you're standing on the surface of the Earth, the force of gravity from the Earth depends only on your distance from the center of the Earth and how much mass there is in the Earth. If you rearrange stuff inside the Earth, it doesn't change how much you weigh and change the force of gravity, right, which which is cool to think that if you go down to your basement, you literally weigh a little bit less, right, a little bit more, sorry, a little bit more. You get an airplane, you weigh less because you're further from the center of the Earth, and so you have a smaller force. But if if you go down into your basement, then there's less earth down. No, you're right, yeah, you're right. Yeah. If you drill into the earth, right, yeah, then there is less earth inside that sphere whose radius is your distance from the center of the Earth. Yes, you're absolutely right. So as you drill into the earth, your weight drops because eventually goes down to zero as you get to the center of the Earth if you're exactly the center of the Earth, and the gravity from all the bits cancels and you feel no force of gravity. So if you're trying to lose weight, just go down to your basement and yourself or or get an airplane. Interestingly, the force of gravity. Force of gravity is strongest on the surface, right, because as you leave the surface, you increase the radius from the center. The mass need is the same, but the radius increases, and if you drill down as the earth, the mass decreases faster than the radius squared term. So the surface of the Earth is where you are the heaviest. Well, um, we were talking about black holes though, that's right, um, But the point is if you took all the mass of the Sun and you squeezed it into a ball three kilometers of radius or less, it would be a black hole. But physics can't accomplish that. So right, so you know, hey, if aliens came by and they did something weird to the Sun, they could turn the Sun into a black hole. So let's explore that scenario where the hand of God or aliens turned the Sun into a black hole. What would happen. Let's get into that. So, assuming that it does happen, let's find out what it means for us. But first let's take a quick break. All right, So the hand of God Daniel came down and or went up and squished the Sun down into a black hole and uh, or Aliens went out there and use some special machine to turn our son into a black hole. What does that mean for us? Yeah? What does that mean for us? And I think a lot of people think, well, black holes suck stuff in, and so if there's a black hole that nearby, it would just suck us in, right, and that would be the end. And a lot of people we interviewed said that, But remember that gravity is not all powerful. Right. There is already a very strong gravitational force towards the center of our Solar system from the mass of the Sun. But the Earth is not getting sucked into the Sun right now? Right? Why not? Because the Earth is in orbit. It has too much velocity. Right. You can think of an orbit. It's sort of like constantly falling towards the center and missing because you have too much forward velocity. And that's what the Earth is doing that falling. Would you miss so you come back around and you miss again, and you come back around and you miss again. That's when being an orbit really mean. Yeah, sort of like forever falling down the stairs. Right. And if the Sun became a black hole, it wouldn't change the mass of the Sun, right, We're talking about just squeezing the Sun down to a smaller radius that becomes a black hole. It doesn't change the mass. And the gravitational forces we were saying a minute ago depends just on two things. The total mass inside that sphere, right, the sphere that's the radius um that's your radius from the center of the mass um. That's you mean, like all the maths, it's closer to you to the center of the Sun or the black yes, exactly um. And so if you're just squeezing the Sun smaller, that doesn't change that number. So it depends on that that the mass, and it depends on your distance from the center of the mass, right, and that number is not going to change either. So you could take the Sun and squeeze into a black hole, it wouldn't change the Earth's orbital dynamics at all. Just because it's a black hole doesn't mean it magically has a greater gravitational poll. It's the same gravitational force. Nothing magic happens when it becomes a black hole, that's right. The only thing that changes is the gravitational effect um on things that are super close to the black hole. Before the Sun became a black hole. In this hypothetical example, the closest you could get to it is the surface of the Sun. That's where the strongest gravitational force was. Right Now, because you've squeezed the Sun down, you can get closer, and so there is a stronger gravitational force, right because you can get closer to this, to this mass than just the surface of the Sun, than the radius to the Sun, because now you shrunk the radius down. So there is a region, a new region where the gravitational force is stronger than anything used to be. But the Earth is not in that region, and the gravitational force at the rateus the Earth doesn't change at all. So the Earth would just orbit this black hole the way the Earth orbited the Sun. I think it might make we help people to think about, like maybe not like a dramatic collapse into a black hole, but just like imagine the Sun you know, shrinks a little bit, you know, like gets a little bit more dance or compact, or if it like fluffs up a little bit and gets a little bit bigger and fluffier, it's still the same amount of mass. And so our orbit wouldn't be effective if the Sun got a little bit fluffier or a little bit denser. Right, that's exactly right. So if the Sun shrank by one percent, right, and the mass did the same, it wouldn't change our orbit. And so if it shrank by or yeah, we still be going around the exact same orbit. Yeah, exactly, And and things do orbit black holes, right, The most direct way that we've seen black holes is from stuff orbiting them. There's a black hole in the center of our galaxy, and we see stars moving around it, and we can calculate the mass that black hole based on the orbit of the stars. We see gas orbiting black holes and being squeezed in the sage by the title forces and emitting crazy radiation, and so we see stuff orbiting black holes. Stuff does orbit. It's not like everything near a black hole just automatically get sucked in, right, And so the same thing would happen here. Well, I guess the part that is tripping me up is that, you know, I can imagine the Sun collapsing ten percent and still the Earth goes around on the same orbit. But you know, at some point the Sun, you know, something sort of magical happens, right, like suddenly becomes a black hole and you have an event horizon and you see the black dot. And so you're telling me that really, nothing sort of magical happens, right, like nothing from our point of view, nothing changes, Like the fact that it suddenly became a black hole doesn't suddenly make it like a bigger sucker. That's right. It doesn't make it bigger sucker stuff at our radius, right, so you know, one a U nine million miles from the Earth, the force of gravity doesn't change. Also, at where the surface of the Sun used to be, the force of gravity hasn't changed, because again you're at the same distance, right, and the same amount of stuff. But now I say you were like at half the radius of the old sun. Right, this is a place you can see that's now empty space that used to be the center of the Sun. So you couldn't get there. But now there's a spot there where there's incredibly strong gravity. You can get closer and closer to the surface. Remember, as we said before, the strongest gravity of any object is at its surface, and now that surface is much much closer to the center of all the mass, and so on the surface the gravity is much much stronger. So it is sort of magical in that way. So it's it's sort of like you open up new real estate in our solar system, but you you sort of don't want to be in the real estate because the gravitational forces are going to be crazy. Exactly. You've opened up new, crazy, intense real estate, but it's on a crazy hill, and you don't want to buy there exactly, um, because you're just gonna roll right down into the ocean. Um. And and so you know, people might feel like, oh, well, how can it not change anything to create a black hole? It does change something, right, It just doesn't change anything outside the radius of the old Sun because they're the gravity is the same. It wouldn't affect our orbit, right, Like the Earth would still take a year to go around it, and we would probably still spin one once a day. Um, but it would probably have other pretty bad effects, right, yeah, absolutely, all right, let's get into that. But first let's take another quick break. All right. I know, so if the Sun became a black hole suddenly, we wouldn't affect our orbit, right, We would still go around in once a year, and we would still spin around one a day, but it would have other kind of bad effects, right, that's right. If you have solar panels on your roof and you're using them to power your tesla, for example, then you're gonna need to figure something else out because if the Sun becomes a black hole, it's no longer fusing and no longer giving off light, and that light is the source of all energy and you know, animation of life on Earth. And so yeah, again pretty dark eight minutes later, and uh, sort of never lighten up again. It would be basically nighttime forever. Wait, so that a black hole is totally cold, right, It's not emitting any radiation or light. It might be emitting some very very low level of radiation called Hawking radiation, but that's never been experimentally confirmed. And even if it is, it's a tiny amount of radiation. And I mean the amount of radiation the Sun currently gives out is incredible. I mean it's almost a hundred million miles away, and yet it can burn you, right, can fry your eyeballs if you stare at it for a few seconds. So the amount of radiation coming off that thing is huge. Now you suddenly just delete all that radiation, right, and so the Solar system becomes a very dark place very quickly. Wait what happens to all that radiation? It just stays inside of the black hole. Now, well, the radiation comes from fusion, right, Like, where does that radiation come from? The Sun is a huge ball of plasma. It's fusing and releasing energy, right, and a black hole is not doing that. A black hole. Usually a black hole's form when a star can no longer do fusion, right, because the fusion is preventing a star from collapsing. Gravity is pulling the star in trying to squeeze it down, and a fusion is this explosion. It's constantly happens blowing the star up to keep it from getting squeezed down. And so if the aliens come and they squeeze the Sun into a tiny little black hole, then you know, who knows what's going on inside there, but nothing is coming out? Yeah? Wow, So it would be super weird, right because like if it happened right now, we wouldn't feel the difference right away, you know, like we would still be able to walk around. The Earth would still be spinning, we'd still be going in an orbit, but it just be like complete night all the time exactly. I mean we'd have great we do with great astronomy for a while, right until we ran in a power and food exactly. Yeah, no light, no heat right, Um, that would be pretty bad. And we rely on the Sun for a lot of stuff. You know. It fascinating to me though I didn't realize until recently that life on Earth didn't start in a way that was taking advantage of the sun. Right. Photosynthesis took a while to develop, like you know, hundreds of millions of years, so very very early life on Earth didn't rely directly on the Sun the way all life on Earth are almost all life and Earth currently does it relied on like geo thermal energy, right, energy from the heat of the Earth. Yeah, exactly. So there might be other sources of energy you could tap into. You have to drill down into the earth and and find some warmth there, um, but it would be pretty dismal. Your teslas certainly wouldn't be running very long. You could get energy maybe from the center of the Earth, right and power up lamps to grow your vegetables. Would that be possible. That would be possible, Yeah, but not for feeding billions of people. I mean, we have a huge fusion reactor out there in the center of the solar system just just pumping out energy, and we're just psiphing off a tiny little fraction of it to grow all of our plants to feed all of our people, um. And so we lose that. We do not have something that we can just like slot into place. We don't have a backup star, you know, a backup source of energy that can replace the Sun. Not yet. In fact, we're getting more and more reliant on solar energy because because we treat it as a renewable source of energy. And so I read recently that like now in the US at least or in Texas even um wind and solar power are providing war energy than coal. Right, coal is stored energy. We're digging up from the earth. Well, which is good news, right, it is good news. Of course, the hand of God comes down and smells out the sun, which the people in Texas um. You know, I don't know where I'm going. I don't know either, but I don't know where this podcast is going because it sounds like we're sort of promoting coal as backup for alien invasion or something. I'm not sure. Yeah, yeah, Just to be clear, we don't expect the hand of God or aliens to turn our son into a platform anytime. So it's all those solar panels that is probably the best thing for us right now. Yes, exactly. We are just exploring crazy hypotheticals in today's podcast. We are not giving you survivalist advice. We're going to be on the cover of Coal magazine, scientists come out in favor of coal. There we go, you're the one percent, Daniel Um. And you know, there's other interesting things like you get no more light from the sun, you get no more heat from the sun. You also there'll be no more solar radiation, which means like no solar wind. And the solar wind is these charge particles that come off of the Sun. You know, also a product of fusion that give you things like you know, the Northern lights, and so not only would we have night all the time, but we wouldn't even have you know, cool fancy glowing lights in the North and South Pole. Although I feel like that would be the least of our worries, you know, if the sun went out. If the sun went out, yeah, but you know, um, I figure at least you'd be able to have great night camping. But you know, all right, well it sounds like it wouldn't if the Sun turned into a black hole. You know, it wouldn't be a total collapse of humanity right away, right, Things would sort of still keep going. But eventually, Um, having no sun would be bad news for other reasons other than physics. That's right. If the sun went black hole. You wouldn't die in the way you might have expected, but you almost certainly will. I don't that's something that's right. But we don't expect the Sun to become a black hole. And though we do expect the Sun to expend its fuel and end its life as a cozy white dwarf, that also won't happen for billions of years. And so none of this is a reason to forget the very real ways in which we, we humans, might extinguish ourselves or destroy our planet by worrying about crazy, hypothetical astronomical problems that are very unlikely to bother us. But I think it's it's sort of tells you a little bit about how physics works, you know. It's sort of interesting to think that even if something like this happened, a lot of physics would just still keep going. Yeah, physics never quits, right and just keeps chugging along. All right. Well, we hope you enjoyed that discussion didn't get to alarm, and please remember to still get those solar panels um and that wind energy. Please, that's right. And if you are the aliens listening to this podcast, please don't turn the sun into a black hole. We need it all right, Well, thanks for listening. We go to joined that. And if you have questions about weird things that might be out there in the universe, weird things that might happen to our planet, please send us an email to Questions at Daniel and Jorge dot com. We love your questions, crazy or not, hypothetical or conceptual. See you next time. If you still have a question after listening to all these explanations, please drop us a line. We'd love to hear from you. You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge That's one word, or email us at Feedback at Daniel and Jorge dot com. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of I Heart Radio or more podcast from my Heart Radio. Visit the I heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows. M