Listener Questions 7

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Speaker 1: Hey, Daniel, have we gotten any exciting messages in our podcast mailbox recently? Oh? Yeah, I gotta say it's kind of refreshing because now the questions in the inbox are mostly back to asking science questions. Back to asking science questions. What do you mean have they not always been about science? Well, you know, until a couple of weeks ago, most of the questions we're asking something else. Here's an example. Hi, Daniel Horror. Hey, this is Oliver and I am a very important question about the universe. Where is Horgey? Thanks? I love your show. Oh that's so cute. Thanks. Thanks for the concern, Oliver. But do you prefer science questions? Daniel? Science questions have answers, you know, science questions or something. I'm supposed to be an expert about. Where Jorge is nobody knows. Hi. I'm or Hamm, a cartoonists and the creator of peach d Comics. Hi. I'm Daniel Whitson. I'm a particle physicist and an avid answer of listener questions. Welcome to our podcast, Daniel and Jorge Explain the Universe, a production of I Heart Radio. Yeah, this is our podcast where we talk about the great Big Unknown questions of the universe, what's going on out there? And often we deal with the questions at the forefront of science. What are scientists thinking, what are they trying to figure out? Zooming? You are all around the universe to take you to the forefront of science and explain it to you. But sometimes we also like to answer questions not just in the minds of scientists, but in the minds of everybody out there. Sometimes I bet some of the great questions and science come from just regular people wondering about this kind of stuff. Hey, socientists are regular people? Are you suggesting we're not? What what you think? I put on that lab code and all of a sudden I become somebody else. Yeah, you become irregular. I'm going to take that in the best way possible. But I think you're right. I agree with you. I think that a lot of the questions that are at the forefront of science, the questions that are burning, that are deep, that are fascinating, our questions that everybody has because everybody wants to know the answer to questions about the universe. People wonder how do things work, and how do they start? And could we blow up planets? And you know, these are basic questions everybody wants to know the answer to. Yes, So to the on the episode. This will be I think maybe episode seven in our series of answering listener questions. So today we have some really interesting questions here about what happens when black holes are born and whether or not we can build something out of a nineteen six movie. That's right, and we love answering listener questions. If you have a question about the universe you'd like us to answer, please send it to us at questions at Daniel and Jorge dot com. We right back to every email, hopefully with an insiphle answer, and sometimes we even feature those questions here on the podcast. Yeah, we answered everything except where I am that one? Oh No, I right back, and I just say, I don't know. I just work with this guy like three different projects. How would I know? Yeah, that's basically it. Yeah, So today on the podcast we'll be answering listener questions, and we have what happens at the moment a black hole is made? Can we build a death star? Those are the burning questions in our listeners minds, and I just want to encourage you one more time to send us to your questions. Sometimes I know the answer run off the bat, but sometimes I have to go do a little bit of research. Talk to an expert on black holes, talk to an expert about death stars, and that's a lot of fun. So please continue to send in your questions, not just because it sends me down rabbit holes where I get to learn about crazy stuff, but also because if you have a question about the universe, probably somebody else does too. Wait, Dinel, I have two questions just from what you just said. First of all, you're you're not an expert at at everything in the universe. I'm an expert at putting on a lab coat and sounding like an expert who gave you a microphone? What? And the second question is that there's actually an expert on death stars out there in your department or in some university. Yes, absolutely, they are experts. In astro industry. You know you're gonna build something really big. You're not going to assemble it on the surface of the Earth. You're gonna have to build it in space. And surprisingly people have thought about that astro engineering. Yeah, astro engineering. Can you study that in college? Can I study that in college? Not today, not tomorrow, but coming soon to a rebel planet near you. Maybe we should take a page from our president and just call it a space engineer Space force engineering US spence much time wondering if you could build a death star. You never thought to ask if you should. Yeah, but we love getting questions from listeners, and so today the first question we have is from Glenn, who is from Cape Town, South Africa. And Glenn has a pretty interesting question which I don't think we've ever covered here, right, No, we certainly have not. We've talked a lot about black holes, but we've never really asked or answered this specific question. Yeah, so, and um, it's a pretty cool question. And so here is Glenn from Cape Town, South Africa. Hi, Daniel and Joge. This is Glenn Edwards and I'm from Cape Town, South Africa. I'm pretty interested in all things space related and I've been really enjoying your podcasts. I've heard a lot of different discussions about black holes, so I have a very basic understanding about the factors that lead up to its formation. One thing, however, that I've never heard about, is the actual mechanics of the moment of black hole begins when extremely dense cosmic object collapses into a black hole. Is this an instantaneous event or something that happens over cosmic time frames? If you are observing this object at the moment of collapse, would it suddenly go out like a light? Have any black hole formation has ever been observed? Would anything within the Schwartz Child radius suddenly disappear? That's a lot to unpeck, but I'm looking forward to hearing your entertaining answers. All Right, Basically, I think the question is what does the baby black hole look like? For or maybe it's more like a bird's in the best question about black hole? Yeah, I think he wants to see the black hole pop out. He's curious about that transition from not black hole to black hole? What does that look like? How does it happen? This kind of stuff, Yeah, because you know, we have sort of pictures now of what a black hole, an adult black hole looks like, but we don't know kind of like the process of making a black hole. Yeah, really a fascinating question. How does that happen, How fast does it happen? What would it look like if you were there watching? This really goes to the heart of what it's like to be a black hole and how the black hole has made So I thought this was a really fascinating question and actually went down and spent like an hour of talking to an expert in my department, Aaron Barth, who's an expert in black holes supermassive and not supermassive about exactly what this would look like. Super fun. Thank you Glenn for this excellent question. That's the question, And it's like, if you were out in space watching the birth of a black hole, what would you see? Would you would you even survive the experience? I guess this is my main question. Do we want to see a black hole get born? Well, maybe if you were watching it from the viewing portal of a death star and had like, you know, a lot of protection, then you could survive at force field a force field. But I think the first thing to understand is sort of the time scale of the process, Like how rapidly does a black hole get formed? Like how quickly do you go from star to black hole? Is it like geological cosmological time scales of hundreds of millions of years or does it happen really fast? I think that was the first question that popped into my head when I read this. My question is, um, what reminds me what a black hole is? Or like, what's a technical definition so that we know at what point it is a black hole? Right? Good point? So a black hole is any location in the universe where gravity is so strong that nothing can escape its gravitational field, and an area of volume of space or like a point, or it's a it's a volume of space, it's like a sphere, and we don't know what's inside the sphere. We don't know how the matter is distributed. A lot of people have their an image in their mind of a point like a singularity, a super dense point inside the black hole that has so much mass that the gravity around it is really strong. And that's the picture you have from general relativity. And we know the general relativity is a great theory. The university describes a lot of things correctly. We don't know that it's correctly describing what's happening inside a black hole, but it's it's a good starting point. And and the structure there is you have a dense dot and the singularity huge amount of mass, and then at some radius, some distance from the black hole or closer, the gravity is too strong for anything to escape, and that's what we sort of called the surface the black hole. It's a three D hole, right, like a it's like a sphere, but it's a whole. Yeah, in space. I think if it's sort of like a like a trap in space, like once you get in there, you can't get out. That space is sort of one directional, Like you get in there and all you can do is move closer to the center of the black hole. You can't ever move further from the center. Um in some sense, like you just call it a trap trap hole. I think that was vetoed is not safe to work um. And one useful thing to remember is that it's not like gravity is pulling on photons and slowing them down, but eventually they will escape. They cannot escape, and not just because gravity is so strong, but because gravity is actually bent the space. You know, there's there's no path outside the black hole. Like every direction you move you're inside the black hole takes you closer because space is bent in a really weird way inside the black hole. So it's not like it it grabs things and holds them with some force. It's like it's like it's really kind of like a pocket in space. It's like a hole in space itself. Like you once you go in there, you're trapped in It's in your own little space, that's right. And it's not like quicksand right where it's just like slows you down. It's hard to climb out, but if you try really really hard or whatever, um there's just no way to do it. And so it's like a trap. It's like a hole in space. And and the point I wanted to make earlier was that we know this surface exists, We know the black holes are real, and that there's this event horizon the surface beyond which if you pass you can never escape. We don't know what's going on inside there, because we don't really know if general relativity is correct at these really really strong gravitational fields, and quantum mechanics says it's probably wrong, but we've never looked inside a black hole, so we can't quite tell. But it is um, like you said, it does have sort of a surface reboundary, and so it's a it's a thing, And so I guess the question is like, how does that thing get formed? Does it started really small and then grow or does it immediately pop into existence? You just go online to Amazon and you enter black hole and you press by now and boom, there's your black hole. There's a buy now button for the universe only for Prime Now I get black hole Prime delivery. Um, it's it's quantum Amazon. I was actually thinking about that because the gravitational information travels at a finite speed. Right. If you create a black hole as a singularity, then the space around it doesn't know about the black hole instantly, so it takes like a moment for the black hole the sphere to sort of be created and to travel out to the eventual event horizon. There's like a huge gravitational wave that would be created if you were able to Amazon prime singularity into existence. Yeah, the question is if you instantly pop a singularity out into space, Um, what happens? Right, Like you're saying, it may not. It might propagate out slowly, or it might um who knows, right, because it's bending space at the same time. So it's it's kind of weird, right. Yeah. If you were a photon and you're flying in some direction and somebody creates a black hole right behind you, in theory, you could survive even if you're right next to that singular already because you could like travel faster than the gravitational waves that are propagatting out from the singularity to sort of inform the rest of the universe that singularity have been created. Because remember, gravitational information is not instantaneous. The Sun disappeared, for example, the Earth would keep moving in its orbit for eight minutes until it got updated. Right, It's like that scene in every other action movie where there's an explosion or a tidal wave or something and the heroes are in their plane or a car just barely outrunning the shock wave. No no, no, no, exactly they die from the burning building. But that's not the way black holes are actually made in our universe. It's just sort of like the extreme example, black holes come from huge masses that already exist. Okay, so let's step through that how exactly black holes are made and what maybe actually happens when they get made. But first let's take a quick break. Okay, Daniel, So how do I make a black hole? What's the what's the recipe here? It's a huge blob of stuff and that's about it. Get a huge blob tablespoons of the zillion tablespoons of anything and then mix. That's the recipe. You don't even have to mix. You just wait, you know, preheat the oven to two point seven three degrees kelvin. That's a temperature of the universe. And then just wait hundreds of millions of years. Well, you kind of have to um make a dough in no way, right, You have to get it on the in a certain amount of space. Like, you don't just need a lot of stuff. You need a lot of stuff in a small amount of space. Yeah, And that's what gravity will do for you. Given enough time, gravity will pull together a huge blob of gas and squeeze it and eventually squeeze it so much that becomes a star if it's big enough, and that star will burn. And the reason it doesn't just immediately compress it into a black hole is because of the burning. The burning creates a lot of energy. It's like radiation that's pushing out, so keeps it from collapsing anymore. Like you might wonder why doesn't every blob of gas just immediately turn into a black hole, It's because there's some force outwards and that comes from this fusion. It's burning, and so it's kind of diffusing the stuff out, making it fluffy, not concentrated exactly. It's a constantly exploding fusion bomb, so it's throwing everything out really hard. At the same time gravity is pulling in, so it's a delicate balance. A star, it's this exploding bomb that's trapped by its own gravitational power, and that goes on for hundreds of millions of years, depending precisely on the size of the star, etcetera, while it burns all that fuel. Okay, so then how does a black hole get formed or how do what are the different wayte black holes come to exist in our universe? Well, the thing that's preventing a star from being a black hole immediately is this burning and so essentially you have to wait for the fire to go out. After hundreds of millions of years, it's turned that hydrogen into helium and then into lithium and into heavier stuff, and that stuff can burn also, but eventually it turns into something that can't burn, which is iron, and so it runs out of fuel. Most black holes come from stars? Is that is that the path through a black hole? Or can a black hole form any other way that's not through a star? We're not exactly sure, like the supermassive black holes that at the center of galaxies, we still don't know what seated them, Like if you try to model them just from coming from one star and then gobbling up other ones, there's not enough time for them to get that big, and so there's lots of different categories of black holes. But we think that's sort of your vanilla black hole that comes from a star happens in this way, but we don't know if that's the dominant fraction of black holes. Also, some black holes might have been made at the Big Bang. They're called primordial black holes, and those could still be flying around they were made in the Big Bang. Yeah, these are the o G black holes. So as the as the universe was expanding rapidly, like, that's how you got black holes. Yeah, Well, there was crazy energy density back then in the very first moment of the universe, and you quantum fluctuations and made some spots more dense and some spots less dense, and then all that stuff turned into all that energy turned into some kind of matter. Some it became very on it and became dark matter. Some fraction that we think might have turned into primordial black holes, which is just a cool word. Primordial black holes. Yeah, it's like a black hole emerging from the swamp. That's what I have this image in my head, swamp of what the swamp of the early universe, you know, pretty big bang. Yeah. So you say, most black holes we don't know how they're made, the big ones and the ones that were at the beginning of the universe. But a lot of the black holes we know about and see do come from a process that we know about, which is from collapsing stars. So it burns through all this fuel that's keeping it from collapsing, and it gets heavier and heavier and denser and denser, and then once it gets enough iron in the core, it can't support itself anymore. Gravity basically wins, and it starts crushing the star down even more and more dense, and then there's I then that's when it's super novas, right, Like, there's an event the black hole, and you know, like every good movie, the sort of drama accelerates. The first stage is really long and boring set up, like hundreds of millions of years of burning hydrogen, and then it burns helium and that's less time, and then it burns lithium or whatever, and that's less time in the last stage where it's like trying to burn iron, that last for about one hour and then it collapses and it's like that happens in seconds or less than a second, and the edge of the star collapses at something like a quarter of the speed of light. So the whole thing happens like really quickly. You go from star that's sputtering to collapsing, and then the whole star just kind of falls into itself. Yeah, and there's a lot of really interesting physics there, like it's collapsing so rapidly that you get shock waves, and those shock waves we think can create gamma ray bursts when like layers of the star bump into other layers of the star that aren't quite collapsing as quickly. We talked on this podcast once about these gamma ray bursts, hugely intense bursts of light that lasts like three or thirty seconds that come from places we don't understand. It might be the themes are happening sort of at these moments just before the supernova, at the creation of the black hole, but we're not sure. And it collapses from gravity right like there's no longer a fire kind of keeping everything out, and so everything just finally says, all right, we'll come together as gravity tells us precisely, and gravity just gets stronger and stronger a right. Gravity is just sort of like winds, you know, it's like interest in your bank account. The closer stuff it gets together, the more gravity pulls. The more gravity pulls, the closer it gets together, and then it accelerates, and so it gets really really strong. And then at some moment the gravity is strong enough that you get an event horizon that's formed. Oh, I say, it's pulling stuff in so quickly that you do get the conditions for a black hole. We talked before about like neutron stars. And sometimes a supernova doesn't result in a black hole, right, Sometimes it does, that's right. Sometimes it can come down to another dense state that's stable, like a neutron star. Everything has been squeezed so much that all the protons have absorbed electrons and turned into neutrons, and they've created this state that they can hold themselves together and resist gravity, like one last more gasp before it turns into a black hole. But sometimes it go straight to a black hole, right, And the difference is that just at the rate of how fast it collapsed or what. Most of the difference is the initial amount of stuff. If you have a big enough blob, then I think you get to skip the neutron star step and just go straight to a black hole. The whole thing happens more quickly the more mass you have. And really it's about density. I think you said once in the podcast, which is cool, that anything can become a black hole if you make it dense enough. And so we're not changing the mass of this initial blob of gas, We're just squeezing it down. At some point you make it dense enough, then you have more mass and less space than the gravity becomes strong enough to give you an event horizon. Right like you, You can be become a black hole. I can become a black hole. Everyone can be black if we're all o g black holes. I'm not primordial, man, I've been around to the Big Bang and you feel old. But gez, just because you get reading glasses, it doesn't make your primordial. No, that just makes me hyper my myopic. Um. And then it gets sort of back to this moment we were talking about before, when we like Amazon Prime to singularity into existence, because at some moment there's no event horizon, right, it's just a hot, dense star. And then at some moment there is because there's enough stuff there. It's a supernova. And I hit the pause button and I'm stepping through it super high speed frame by super high speed frame, and I'm seeing it collapse, collapse, collapse, and at some point I have enough stuff within a certain volume to qualify as a black hole precisely. And I think the first moment the event horizon is essentially minuscule is because the densest point is going to be the very center of this star, and that's the first place it's going to cross that density threshold. And then as it gets gobble stuff up, that event horizon is going to grow. And it's not going to grow at the speed of light because that would that would require all the mass to move into the center instantaneously. But it's going to gobble more stuff and then grow quickly out to its eventual size. Interesting, and when you know that first, sure that the center gets danses first, like you know, because you could imagine just the whole thing collapsing from the edges and at some point you just have enough stuff to just have a giant black hole without its starting in the middle. And the other idea is that it could all transition at the same moment, is what you're saying, Yeah, like it. Yeah. I don't think we know the gory details of this collapse well enough to say how rapidly the center versus the edge turns into a black hole. But I think it's if it's gonna be anything, it's going to be the center first, because that's definitely what the strongest gravity is. It might be that the whole thing happens very quickly. I'm not sure exactly about the relative rate of the edge to the center, but it's definitely gonna be the center first. Okay, So the ideas that maybe probably what's happening is that there's a mini black hole that's born at the middle of this collapsing star, and as more stuff comes into it, it grows. Yeah, and so and remember the threshold we're just we're talking about the definition of the black hole is that where that event horizon is. And that's not a physical thing. It's not like you can touch it. It's just a place inside of which there's too much gravity to escape and outside of which there isn't And so it's just like a mathematical definition. If you're actually on the border between give and horizon or not, you wouldn't like your life doesn't change that much. You go in from one side of and I mean, like, I mean your toast. You're probably not in a good place. But it's not like suddenly, um, the skies turn you know, some weird color. You feel different. It's like, no, you are a speghettified piece of toast. But yeah, there's nothing physically different there other than the strength of gravity is now above some threshold rather than below. So I don't think qualitatively it feels very different, except that now everywhere you look in the universe is towards the center of the black hole. I see, you would see like space around you warping, warping, warping, and then suddenly, whoop, it all occurs in on itself. Yeah, precisely. And then every direction you look would be in towards the inside of the black hole. So everything that's outside the black hole would be shrinking down eventually to a dot and then disappear, And then everywhere you look would be inside the black hole. There's no direction you can go that's outside the black hole, and then you're trapped forever and you are trapped or maybe you're on the other side of something who knows, right, Yeah, so let's talk about that. What it looks like from the other side. I think that's pretty cool, like from inside or outside, from outside, because I think his question was like, what does it look like to see a black hole get made? Does it go out like a light? Okay, so I'm I'm in my Death Star hanging out with Darth and watching the point that thing by the way, maybe we create, maybe we collapse the star. Maybe maybe Darth Vader wanted that's start taking out. Do you think he could reach out with a force and squeeze a star the way he can squeeze somebody's neck? Depend somebody medichlorians there are probably I don't know, somebody needs to do a blood test. Yeah. So you're you're on the deck of your Death Star, hanging out with your buddy Dark. Yeah, you primed the force fields and you see this star suddenly collapse boom um. So we see the star shrink really fast and then there's an explosion, right, because all that stuff when it collapses, it like creates stock waves, right like yeah, because not all the stuff falls in, right, some of it gets thrown out, and you get this gamma ray burst, and you get neutrinos, and you get a huge flash of light. But then the star is gone. Right when the flash of light is past you and all that, you know, the hoopla and the drama of the universe has passed you, then the star is just no longer they're burning, right. Instead, all that light that was being produced by the star is no longer being produced because it's no more fusion happening. Well, will you skip the step of the black hole? So we see the star collapsing, boom, a lot of energy and light and strong waves spread out. And as that's happening, there's a little black hole in the middle growing, right, And so you're gonna be seeing less and less light from the star because more of it's going to be a black hole. And you know, practically you probably can't see this thing happening anyway, because you're inundated by the supernova outburst stuff, the gamma ray burst and all that other stuff is going to totally blind you. But if you could somehow see through that and watch what was happening in the core. Then you're right. You'd see sort of the center of the star be hollowed out and turned into a black hole. And so the Star Wars is beginning dimmer and dimmer. If you were wearing like Gamma ray bands, could you just come up with that, that is awesome as a special Gamma ray bands that blocked thegether. You would see the star in the middle like you would see this little black dot just grow into a black circle. Right, Well, you wouldn't see the dot to be at the center of the star, so you'd be looking at the surface of the star, which would be you know, collapsing and doing its thing and maybe still burning in emitting light, but be eaten up from the inside probably, And so you'd be seeing the star get dimmer and dimmer because it's no longer supported by fusion in the inside. Oh man, you're saying a black hole eats the star from the inside. Yeah, it's like one of those tarantula wasps. Oh man, Now I think we need to switch to different sci fi movie. Now we're in like an alien that's right. And and so the star basically just goes out right all that stuff that was burning that was producing light stops and is now just sort of inside the black hole, no longer producing the light. And so it doesn't go out like a light. It's not like it just instantly switches off. It used to get eaten from the inside. Wow. And and at some point you'll see the black hole um burst out of the star almost or like just kind of grow out of it, and that's all you see. Yeah, so I think you would see a black circle appure sort of suddenly because the entire last surface of the star would get gobbled up by it. But remember then, the black hole is not like surrounded by empty space. It can't eat everything that's around it. It's always going to be surrounded by some amount of stuff that won't fall in because it's rotating too fast to fall in. Oh, I see, it's like a mess. It's like a it's it's like the center of a tornado. Yeah, precisely, just the way our solar system has a huge blob near the center of the Sun, but not everything fell in, right, The Earth doesn't fall into the center of the Sun even though there's a huge amount of gravity because the Earth is rotating in the same way. The stuff around the black hole keeps spinning and eventually falls in um, but some of it stays there for a long long time, which is why when you look at that picture of the black hole you see a glowing ring, which is the stuff at the edge of the black hole that has not fallen in. It's still spinning around it hundreds of millions of years later, right yeah, and think about what just happened that like a huge star just collapse, and so there's probably it's probably like a super chaotic environment, you know, there's like stuff that just like swirling around from that crash, right yeah, And so probably you're mostly going to be seeing the accretion disk and the stuff swirling around it for a long time because it's a nasty environment. The gravity there, even though it's not black hole levels, it's still really really strong, and that squeezes all that gas and stresses it and then it radiates. So some of the brightest things in the universe are gas that are right outside the edge of a black hole that we call those quasars when they are at the center of a galaxy, and they're extraordinarily bright in X ray and invisible light. But I guess the main thing is that it would be pretty instantaneous, almost right, like maybe you couldn't even see it with the naked eye, which is collapse. Boom, Suddenly there's a black hole in the middle with all this swirling uh you know, gas burning gas and crazy energies swirling around it. Right, it would be sort of like boom, right, precisely, precisely. The actual transition from star to black hole happens very quickly, probably less than a second, but then it takes a while for the sort of clean up the scene of the accident so you can actually see the black hole with your cosmic ray cosmic gamma ray bands on. You have to wait for the dust to settle a little bit, and then you see the black hole precisely, and then you and Darth Vader cut the umbilical cord and your proud parents of a new black hole. That's right. Then you got to give it a name, and then you argue about that, and he probably wins. He's like an a kid. No, no, we already used that one. I am the feeling Darth Vader wins every marital argument, all right, So that answers Glenn's questions. What happens at the moment a black hole is made a lot of stuff and a lot of very quickly. It seems to be the answer. It's a huge, cosmic, beautiful mess. All right. So that answers that question, and we'll get now into Josh's question about building a death star. But first let's take a quick break, all right. So Josh from Fargo, North Dakota has a question about building a death star, and I have to say I kind of wonder why he's asking this question. So here's Josh with his question. Hi, Daniel Horror. Hey, this is Joshua Higginson from Fargo, and today my question stion is, oh, could we build a death star? I've been thinking about that question lately. I mean, are there even enough resources on the planet to construct such a massive advice? What kind of power would the death laser require? And couldn't really make a planet explode? O? Man, I love how he has music. He had music to this question. Yeah, Josh, it's pretty awesome. I don't think Josh deserves having you impugne his intentions. I think we should. I don't know Josh, but he sounds awesome and I think we should assume that his curiosity comes from the same place that all the questions come from, which is just a desire to know. I don't think Josh is out there wanting to build a death star so he can blow up innocent planets, right Josh. Um, that depends on what his last name is. Maybe Josh Skywalker. And we should be worried a little bit. What do you think about, you know, whether the Constitution text people's rights to build their own death star? Is that a well regulated militia, the right to bear giant satellite? Um stays faring death rays? Hey, how else are you going to protect against the tyrannical government? Right? Good guys with death stars? That's the answer. What would have happened if the Rebel Alliance had their own death star? Yeah? Some people had the death star in their pockets. Um. So, yes, that's an interesting question. And we're going to assume he's just curious, he doesn't actually want to build one for some reason. Um. I guess it's a pretty interesting question. I guess it's like, is it even physically possible to build one and maybe even have a one exist? I guess is the question? Right? Yeah? And it's a great question, and it comes in a long tradition of wonderful inspiration for new technology from science fiction. You know, our science fiction authors are always imagining what the future will be like, how humans will live, and what kind of new gizmos they might invent. And then scientists do this, they say that does seem cool? Could I make that? And so this is a wonderful, long tradition of following up on the ideas of science fiction authors. And for those of you who have not seen Star Wars, which I don't know if it's possible, but in case, I've met a lot of people who haven't seen Star Wars. To be honest, I'm pretty sure the ven diagram of people who listen to this podcast and people have seen Star Wars of overlap well for the occasional outlier. The Death Star in Star Wars was a giant it's it's a giant sphere man made not a moon, right, not a moon, but about the size of a moon. It was actually like a giant space station, right, who's made entirely out of metal that you can see, And it had a giant death rate. It certainly did capable of destroying planets. And so I guess the question is could you even build such a thing? Wouldn't would it be hard to make? Could you know? Would it collapse on its own? How? How could you build it? How would you flight around? Wouldn't it just get sucked into the orbit of other things? And so that's the that's what will that's what will be hopefully answering to me. And it's question. Apparently a lot of people have Apparently a lot of people ask Obama to build one. Yeah, you can write these petitions to the White House there on the website, and any petition that got more than twenty five thousand people to sign on, the White House had to officially respond to the petition. And so in two thousand and twelve thousand people asked President Obama to build a death star, not like hey, could you, but like, we want you to do this. This should be a policy priority. The people's the people's on the internets want I don't know how many of those were actually Russian bots. Do you think the Russians want Obama to build a death star? I don't think so. Well, we have a space force, so you know, we're not that far from a death star. And so, of course the Obama White House did respond as required by law, and they rejected this petition for I think a pretty good Yeah, that's pretty awesome. They said that such a death star would have a fundamental design flaw because it can be destroyed by a single small spacecraft by one farmer from the desert. Send it back to the drawing board. Give me an impregnable death start that one they would build, right, although if you think about it, they did. They did it twice right in Star Wars. It's like the first one got destroyed by a single spacecraft, they build another one. They didn't change the design. It was still vulnerable to a single spacecraft. That's the problem with big government. You know, not very agile, not very agile, but you know, say you wanted to build this thing. And in the movies, you notice they don't build it on on a planet, right, they build it in space itself. They had these awesome scenes. You can see the construction part way through in one of the movies. Well, I think there's several questions here, is like, how would you build it is even physically possible for it to exist? And also that laser can we build a laser like that? And also can we wear cool helmets? Like these guys, where activate the license laser? I think that's the only part that you can do actually to cut the whole question short is where those cool helmets? But it's a it's pretty awesome question. I think can you build something that big? And there's a lot of limitations there. One is just like can you find enough stuff? You know, you want to build something the size of the moon. The Moon is big, you know, the Moon is like twenty five times all the mass of all the asteroids and the asteroid belt. It's enormous times wow. But it's solid. The Moon is solid. But the Death Star, you know, had hallways and trash compactor rooms and hangars, so it's not uh, it's it's not a solid piece of steel. Right. Do you still need a lot? You still need a lot and you know, but we do have the resources. We have planets, We have small moons. So you can imagine you could take some of the stuff from the asteroid belt, and you could take some small moons from some of the planets, and there are the raw materials. They're like the asteroid belt in those moons have a lot of metal. Oh I see, So it's technically possible to build a structure structure like that. Well, I'd say that these sources are out there, like they just don't exist on Earth. Earth steel output every year is pretty small, Like you need about eight hundred and thirty thousand years of humanity's current output is steel to have enough to build a death star. So that's going to take a long time. So you need to find it something, need to source it somewhere else. You need to go to the asteroid steel steel yards, okay, and that's where you could possibly build it. So you can't build it from materials here on Earth. But if you find those materials that in asteroids, you could technically build one. Yeah, I think it'd be easier to get all that metal out of asteroids rather than digging it out of the Earth's crust. And somebody did a calculation like how much would that steel cost? And they came up with a ridiculous number, which is eight hundred and fifty quadrillion dollars worth of steel. That doesn't sound too bad. Isn't that about the the size of the U S deficit at this point? Or that doesn't sound too bad to you? Hey, aorry, can I borrow a hundred fifty thousand quadrillion dollars please, it's just you know, for quarters, I'll take either one, honestly, no, But of course that number is ridiculous because you had that much steal, then it would change the price and you know, dot dot dot economics. But the point is, it's an enormous amount of resources. We don't have that here in the surface of the Earth. You probably have to take a part of Moon or all of the asteroids or both just even get enough resources to build it. But technically it is possible. Well, there's there's a structural question also, you know that's like can you get enough steel? But you put enough steel together and it has a lot of gravitational attraction, you know, it weighs a lot. Yeah, I was just pulling itself, Like, think about what prevents you from building a steel tower that's like twenty miles high. Well, the top of the tower is pressing on the bottom of the tower, and the tower twenty miles high, and the the twenty miles of steel pressing on the bottom, so the bottom is going to get crushed. So if you're gonna make a moon sized object, then it's going to start to get its own gravity and it's gonna put some stress on it. Oh man, let's not get into gravity and star Wars, because I feel like we had We can have a whole episode here about where do these spaceships get gravity? And star Wars? Alright, So, assuming we have perfect control of gravity, we can manipulate however we like. Then let's ask a really detailed question about construction of a death star. Yeah, assuming gravity, uh doesn't exist, but producing in our universe right now, if you build a giant structure of steel, it would probably collapse. It's just so heavy on itself, right, it gets pretty thin. Yeah, but I think it probably possible. Remember, gravity even on the Moon is not that strong compared to gravity on the surface of the Earth. So if you're out there in space, there'd be some gravity just from its own attraction. But I don't think it'd be a limiting factor. Oh, I see, you could maybe like m oh, I see, like a steel tower on Earth would collapse because it's on Earth, but a steel tower out in space wouldn't feel the same gravity to collapse. Yeah, you need need to make this a start and be really enormous before the gravitational forces would play a significant role and have to have, you know, mass more than the moon in order to have significant gravity. Well, that's why you would really lean on your astro engineers precisely, precisely, and maybe they come up with a better material. You know, maybe steel is not the material of choice for building your you know, intergalactic death bomb. Maybe you wanted out of a different material, Yeah, aluminum or something else. I'm not sure. All right, Well then, um, it seems like it's plausible. There are resources out there and and there might be a good way to engineer the structure like that. But then I guess the question is can can I make that laser the cool green laser that can destroy a planet? And that's what it's really about, isn't that Everybody just wants to build a really big gun. Well, do you think, Josh this is the part Josh was interested in, or was he interested in the astro engineering part of it? I don't know. I wonder if Josh has a laser in his garage and these building and he's wondering, like how big could I make this thing? He's like, I can't get it big enough. I'll ask Daniel Horror. Maybe they can chime in, Maybe they can help me destroy the universe instead of explained it. Um. Well, currently we have some pretty powerful lasers, but they're not anything close to what you would need in order to destroy a planet. Like currently, our lasers can just barely deflect a missile, you know, or shoot down an incoming missile, and there are people working on lasers that might be able to deflect an asteroid. But the most powerful laser we have right now is like two petal wats. Sounds like a lot, but you know, like a light bulb is sixty watts. A petal wat sounds like a lot of zeros. Petat is a lot of zeros, but it takes even more zeros to blow up a planet. Somebody again, did this calculation. Somebody in astro engineering program, I guess, and they calculated that you would need a million billion of two of the two most powerful lasers on Earth in order to sort of damage a planet enough to break it up. Somebody actually calculated this, Like, here's a formula for destroying a planet. This is something in people's minds. You know, you see something on TV, your scientists, you think, could we actually do that? And then you get out a piece of paper and a pencil and you try to figure it out, and you're like, I have tenure, I can do it. I can spend my day doing this. There's probably a journal of death Star engineering that you could publish these papers, and there you go. Aster the Journal of astro Genocide is a phrase I've never heard before and instantly hate astrogenocide. But do you so you need a million billion of the most powerful lasers currently on Earth to make it? But maybe that sounds not implausible. I mean, if we're going to build a death Star and spend eight hundred and fifty quadrillion dollars, why not build a million billion powerful lasers? Yeah? I mean if you have infinite resources and time and money, if you become emperor or the Earth and this is what you wanted to devote all of humanities resources too, it's not totally implausible. But there is one thing about the laser in movie that I think we could never accomplish. Did the green color or oh, we could do whatever color you like? But you know how when they pull the lever, they have this really cool effect where the lasers come out from the edge of the circle, meet in the middle, glow for a minute, and then zap off. Right, that's impossible. Lasers don't do that. They don't like meet and converge and then zoom off. They just sort of shooting a straight line. So it's not as cool looking from the in a cinematic point of view. But you need a single Lasers just sort of shot out of the edge of a muzzle. They don't like come together and converge that way and then change direction in mid space. Oh, I see, it's like, yeah, it was that in the movie. They it's like four or five individual beams that come together and then shoot out to the to the planet to destroy it. That's the part that's unnatural or physically impossible. That's right. But hey, if you want to build your own iron Moon and just shoot out a normal, boring laser to Detroit planets, then I think that is possible. Okay, that gets your ruble. I guess that's in the ridiculous, huge waste of money but potentially possible category. Well, here's a question for you, Daniel, how do you know that the Death Star used lasers? You're right, it could have been you know, projections of the force or some other sort of like weird plasma thing. I'm not sure they technically call it a laser, right or anything. It's just a weapon, that's true. Um, what do they call it? They call it the energy beam. Now we need another excuse to go back and watch that movie. I'm sure we can just post a question online and a few people who have maybe seen the movie a few times, some astro engineering experts. So well, I guess I'm just saying, we don't know they're lasers. Maybe it's something else that could potentially, um have that cool effect. That's true. And if you're gonna be in another science fiction universe where the laws of physics are different and weird magical ancient religions are real, then hey, maybe you can do anything you like. Well, it seems like the answer for Josh here is that it is. Yes, we could maybe build a death star. It would just take a lot of resources and a little bit of money. Yeah, So don't stop working on that project in your garage, Josh, it will work out or no, please please do stop if you're trying to build a laser that destroys the earth. Please. I'm assuming Josh is going to be a good guy with a death star. Oh, I see he's pointing at Outwards and all the bad guys with death stars. All right, So those were two great questions. Thank you to Josh and to Glenn for submitting their questions to us via Twitter and email, and those of you listening, if you have a question that you would like to answer to, Daniel will read your email and your messages and we might even answer it on the podcast. And you don't even need to shoot us with your death star or give us any baby black holes. But thank you everybody for continuing to send in your questions. They're wonderful, they're stimulating, there a lot of fun, and we love an ring them here on the podcast. Yeah, keep asking questions. See you next time. Thanks for tuning in. Before 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 on 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. For more podcast from my Heart Radio, visit the i heart Radio app Apple Podcasts or wherever you listen to your favorite shows.