Cosmic Queries: Science in Movies and TV

Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. Now. Welcome to StarTalk Radio. I'm your host, Neil deGrasse Tyson, your personal astrophysicist. In studio with me, Eugene Mirman. Eugene, love having you, man. I love being here. Oh my gosh, you comedian Eugene Mirman. He's here to make fun of all my answers as to what's gonna happen. Yeah, and to learn, like you, the listener. This is Cosmic Queries edition of StarTalk. This is where we collect all the questions that we accumulate from our website, startalkradio.net or on Facebook, Twitter, Star Talk Radio is our handle there, and we get enough on one theme or another, we put them together. So today is science in movies and other forms of entertainment. Yes. And some people have like genuine questions about it, others wanna know if anything I can pick apart, but I haven't seen the questions yet. No, and I'm gonna, Louis, start in. Let's just start right in, go for it. It's about the movie Contact from Danny Davis. Movie Contact, the story written by Carl Sagan. Yeah, yes. My question comes from the movie Contact, one of my favorites. The problem I'm trying to figure out is the ending when Jodie Foster's character travels in the spaceship and has her experience, but for Earth viewers, the ship instantly falls through like nothing happened, and then it is later revealed that her camera recorded 18 hours of static. Now, from what I understand about relativity, it should have been opposite. On Earth, 18 hours would have passed, but her camera would have recorded seconds of static. Please help me put my mind at rest on this query once and for all. Did the movie get that part wrong or am I missing something? This person knows just enough relativity to just get angry about it. Yeah, so just to remind people in the film, Jodie Foster's character visits aliens in another part of the galaxy and does so in an odd sort of rotating spaceship that never leaves Earth. And they see her take just seconds, and in that time, in those few seconds, she goes on this journey. And I think the point here is that the fabric of space and time is such that you can warp either space or time or both. And so you can basically travel through a wormhole, get to some destination instantly, all right? And if you travel fast, the question, oh, who is it, who is it that asked that? Danny. Danny. He's from where? I don't know, but his name is definitely Danny. He didn't include it. So normally, if you're the one that goes away, you live for a shorter amount of time than Earth that you've left behind. So Danny is perfectly correct about that. But these are aliens who gave us instructions how to build a spaceship to do exactly what just happened. So I'm not worried about that relative time dilation. So Danny's right that it would logically work that way unless aliens gave him a plan that he stuck to that worked differently. Exactly, which is what happened in the film. You could also imagine that she was not the one who left, that it was Earth that left that location and then returned. And then Earth is the one that lives for only the few moments and he's the one that lives longer. You can imagine aliens controlling space and time in such a way that that's what happened. So in the movie, they could have moved the whole planet with or without. That would be hard. It would be hard. No one's saying it's easy. Neil, I am not saying that this is easy. I'm saying that it's within possibility of science fiction. What I mean is that it would be hard not only to physically move the planet, but Earth has to be the one that accelerates away and then slows down, stops and comes back. We would all feel that. You would feel that. Yes. If we went through a wormhole, we would feel it. No, if we slow down, if we sped up and slowed down and stopped, we would just fall over and roll off the planet because we're not attached to the Earth. So. Not even a little. No, not at all. Not even with, not even gravity. So we would all fly away. If you could stop the Earth. If you just stop the Earth from its movement in space or adjusted it in some way, Earth would stop, but we were moving with the Earth in orbit around the sun. So we would just fly very quickly. As you would fly through a dashboard in a car that hits a brick wall and you're not wearing a seatbelt. I really can't believe that people who do jump from outer space or bungee jump or any of that haven't tried to stop Earth to just go flying. That would be a fun experiment. Let's try it. Yeah, so I'm not worried about that, but strictly speaking, if she was the one that went away, Danny's correct. All right. All right, Danny, good job. Congrats. What else you got? You just got your PhD. Okay, this is from Brendan. It's about time dilation effects of wormholes. In the episode Rimmer World of the comedy Red Dwarf. Yeah, sorry, I missed that episode, but go on. Well, it's season six, episode five, he writes. Thanks, Brendan, you just wasted our lives. One of the characters goes through a wormhole in an escape pod that is accelerating away from the other character's ship into a wormhole to a planet that he would land on. They mentioned time dilation effects of wormholes, and the first one through the wormhole had to wait 557 years before the rest of them caught up to rescue him. Would that, how true would phenomena be, how true would phenomena be if the wormhole travel was real? Is that real? Yeah, so a wormhole allows you to go to another part of the galaxy quickly, much faster than a beam of light would take you there. By the way, if you can travel through wormholes, it allows backwards through time travel. That's how you would do it. So just an FYI on that, if you can travel, you're effectively traveling faster than light, and that allows certain trajectories through the fabric of space and time. Are you saying Sliders is pretty real? If they can manage the wormhole part. So the point there is the wormholes, if you're accelerating through the wormhole and you're moving fast, you would not age very much at all, and you come out the other side. Everyone else is aging a long time. But if someone else comes to a wormhole right after you, no, you don't wait 500 years for them, no. No, they'd just be right there too. Yeah, yeah, just come. You're both using the same thing, so it'd be about a minute. Whatever, whatever. And the wormhole could be arbitrarily short time for you, depending on how warped the space is or how tight the hole is between one section of the galaxy and the next. Wait, in fact, this thing that he's describing, he should have just said in the first reboot of Star Trek, there was a wormhole. You don't need to go into season six, episode five of Red Dwarf. This is literally the plot of the first Star Trek. To have a conversation about wormholes, you don't need to be that specific in your science fiction referencing. And you can pick a much broader, I mean, anyway, so same thing about the Star Trek. You wouldn't. Yeah, so the point is if you're all going in together or immediately after one another, yeah, you're good to go. 15 minutes apart, 15 minutes. Don't worry about it. Nice, all right. On Facebook, Robert Millard, this is his thing. I promise I had this thought before I saw Men in Black. We believe you, Robert. You liar. Yeah, okay. It seems that matter is basically mass and energy swirling around each other. The same could be said for solar systems. Is it possible our solar system is an atom or the Milky Way is a molecule? That was a deep thought 110 years ago. People, as we started probing the structure of the atom, we looked at it and said, oh, there's a nucleus, there's electrons, and they're orbiting around. Maybe that's just a mini. But there are no cats and there's no cows and farms and buildings. When we come back, I will give the answer to why atoms are not solar systems. You're listening to StarTalk Radio, Cosmic Queries edition. We're back on StarTalk Radio. I'm Neil deGrasse Tyson. I'm an astrophysicist, and my day job is as director of the Hayden Planetarium at the American Museum of Natural History in New York. Check us out. Eugene, do you have a day job? I mean, I think as much as you, I guess you have a thing that you would call your day job, but it probably blends into some of your nighttime work. And the thing you call a day job, your voice on Bob's. Yeah, Bob's Burgers, I guess, would be. Love to know that, excellent. So we're in the Cosmic Queries edition. Yeah, so someone had asked- Science and movies, right. And so where do we leave off? Basically, they were like, is our solar system an atom or is the Milky Way a molecule? Yeah, and these are great questions, deep questions that were asked about 120 years ago. He's about 120 years late in asking this. Right around when Heshish first reached Boston. It's interesting you have the date for that. So here's the problem, the problem. When we discovered atoms and that there's a nucleus and electrons, we say, hey, that looks like a solar system. I wonder if inside an atom, there's yet another atom and another atom. This is an episode of Mork and Mindy, but yeah. It turns out that the laws of physics that describe what goes on in a solar system are different from the laws of physics that describe what goes on in an atom. And so the conduct of matter and energy is completely different in these two regimes. Really? And because of it, as you mentioned before the break, no, within atoms, you don't have cats, you know? You don't have. Yeah, bulletin boards. This stuff that does not happen inside of atoms that happens macroscopically. So the microscopic world and macroscopic, so the macroscopic. Different physically. The macroscopic world responds to what we call classical physics, right? And the microscopic world responds to quantum physics. Quantum physics actually applies to the whole universe, but on large enough scale, it looks like classical physics and equations are easier. So we just use those modes to describe it. So no, it's not just the Russian egg, the Russian dolls. The nesting dolls, matryoshki. Oh, that's how you say that? Matryoshki, yeah. Matryoshki. Very good. You and I should go to Moscow now. Matryoshki dolls. So no, it's just not that, but it would have been a really cool philosophical revelation. So there's no life inside of an atom or molecule. None that we know of or that we would have ever defined as such, that's correct. That's correct. Okay, okay, next question. All right, what else you got? Oh, I have a lot. Okay, Brian has a question. And he's from where? Brian Hodgson. No one here is telling us where they're from. I think they're afraid we're going to find them and help them learn. If you were an astronaut tumbling through space, like in the movie Gravity, could you change your rotation or trajectory, say through twisting your body? Thank you, love the show, Brian. No, unless you're in contact with some other thing or unless you lose mass. If you do not lose mass or come in contact with anything else, you will tumble in that same way, at that same speed, forever. But you actually will lose mass in the sense that you'll grow hungry and die. It depends. Well, okay. That's a really slow, as people who have tried to lose weight will attest, that is a slow way to lose, there are much faster ways to lose mass. Yeah, but if you're tumbling through space and you don't have access to any restaurants or anything. No, what you can do is, if you open up certain hatches of your spacesuit, you could like pee in one direction or another. This will send your mass out another direction, opposite presumably the way you're tumbling and you don't want to go. That will slow you down. Oh, I do like the idea of someone spinning and peeing and then just, they would just, they'd spin in, in the other direction. They'd still spin. So you'd have to know some angular momentum physics before you went about to say. Started peeing or spitting or pooping or any. Do you think that's the end of gravity is just someone peeing themselves back to earth? I'm just saying, oh, by the way, you can't be inside the suit. It has to actually leave your body. Oh, of course, of course. Into space, right? If you do this, you can then control to some level your wayward trajectory. This is no different. When you die, like say you open the suit, your skin wouldn't be able to contact, but you would. Oh, it's just a vacuum. I mean, yeah, it's not, it won't be comfortable, but you can do it temporarily in order to adjust your, oh yeah. For how long? A couple of few minutes. Oh really? That sounds great. Now I have a new goal, tumble through space for a few minutes, no suit. So the point is that when you lose, if you look at spacecraft, when they make adjustments, if they're in free open space, they're little sort of what they call these nozzles, these rocket nozzles that are strategically positioned around the body of the ship to make it rotate one direction or another, to change the attitude, the angle, or to slow down or to speed up. It is losing mass by the act of burning fuel that sends gases out in one direction or another. Yeah, so anything that comes up, a burp, any other flatulent activity, okay? Yes, that all the things that are funny to children become the way you survive tumbling through space is what you're saying. Every bodily function that you're not supposed to discuss during the day in school, you need to survive to fly back to the earth. Yes. Sounds like a plan. All right, here we go. This is a question from Robbie. Oh, and he's at the University of Michigan. He didn't mind telling us where he was. Excellent. And here's his question. So he could be a student or a professor, we'll find out. It's true. Well, depending on how good his question is, we'll know. Or an administrator. He used a lot of exclamation points, he's probably a student. Oh, the OMGs and exclamation points, right, okay. Yeah. While at home, I was watching Futurama and during the episode, the characters land on an alien world that had three suns. It left me wondering what would happen if there was a second or third star in our solar system, either in orbit around our sun or fighting with it to become the center of the solar system. Thank you and thanks for the show. Ooh, so here's the problem. If you start throwing extra suns in the middle of your star system, depends on how far away your planetary orbit is. If you're not far enough away from all of them, let's say it's a triple star system. Do one up on what they showed in Star Wars. So let's have a triple star system. If you're not really far away from all three. What's considered really far, like Jupiter? Much farther than any one of them are from each other. Okay, so it's a relative statement. So you wanna be far enough away so that all three stars feel like one source of gravity, to you. I see. If you're too close and one is over to the left and one is over to the right, your gravitational allegiance becomes constantly compromised. Who am I orbiting today? Oh, it's this star, not that one. And you'll become really close to one star and far from another. Your climate would be all to hell because you wouldn't sustain a stable temperature environment. And you can do models on a computer to show what happens to these orbits and most of them are unstable. Right. A star will either fall, a planet will either fall into a star or be ejected from the star system altogether. But it would be fine if you simply were so far away that they felt like one. They felt like one and they did it right in Star Wars where they had the double sunset, if you remember that scene. Those were far enough away from the planet, but the planet is really only seeing one sort of collective gravitational. And so that's the problem that you have here. But otherwise it'd be really cool, it'd also be cool if the stars were different colors. And then you'd have a. Yeah, as one star set, the color of your sky would change. What are some of the options? You can have red stars, white stars, blue stars. You don't have green stars though. Why not? You want me to get into, I can't get into that now. Oh wow, okay. Finally stumped with green stars. Ah, it's exhausting, there's no green in space. No, there's green in space, there's just no green stars. There's plenty of green. No, now you have to tell me why there's no green stars. Finally I went to a real piece of science and you're like, no. Okay, fine, there's actually green emissions from gas clouds in space and we looked at it and we looked at its spectra, we didn't know what it was and we as my historical brethren in the field that I study and in fact it was named of nebulae and it was called nebulium, this green light in space. Nebulium, that was a placeholder until we actually figured out what it was. We figured out it's actually oxygen behaving in ways that we've never been able to reproduce in the laboratory. Under the rarefied vacuum of space, oxygen behaves badly or good, depending on how you wanna look at it. It's a green cloud that's coming for us. So it emits a beautiful green light and if you're angstrom fluent, it's 5007 angstroms on the scale. So you can have green light coming from gas clouds but stars, because they're giving off a whole spectrum of light, green is this narrow part in the middle of the spectrum and when you puddle together all the light, but you can lean towards the red side of the red. Because it's not a primary color. Because red, orange, yellow, green, blue, violet, that whole spectrum, it either leans to the blue side, it leans to the red or it gives about the same of each and that'll give you a blue star, red star or white star. You're not gonna get a green star. That's why. All right, here I'll ask one more question. Oh, you've got about a minute left? Yeah, go for it. A minute left in this segment, but go. Yeah, yeah, this is from Harrison Bizzle Fizzle. It is. Dear Neil deGrasse Tyson and funny person, how can one fly a kite? I watched Mary Poppins recently and it got me thinking, if one had a long enough string, how high could a kite possibly go if the kite and string were made of a sturdy enough material? Could it go up through the atmosphere, up where the air is clear? Anyway, it goes on. Oh, let's go fly a kite. I love that question, especially since I also love that song. I love corny Broadway songs. So what you need is enough updraft to keep the kite afloat against the weight of the string that's pulling down the kite, right? We gotta say, don't forget that. And let me pick up on this answer when we come back to StarTalk Cosmic Queries Edition, Science in the Movies. Thanks We're back, Star Talk Radio, Neil Tyson here. So kites, how high can a kite go? Again, thanks for doing this. Great question we left before the break about how high up can a kite go. A thought brought on by watching Mary Poppins. And by the way, at the end of Mary Poppins, where they're all flying kites, all kite string angles are the same, as they're all standing there. I just want to make note of that. That would be true if all the kites are high, flying at about the same height. And then the wind is the same for everybody, and so they did that accurately. So I want to commend the Mary Poppins creators of the movie. For accurately presenting the kites. Oh, good. So how high up can it go? So you have to watch out, because the higher the kite goes, holding wind currents aside for the moment, the higher the kite goes, the more string is dangling beneath it. You reach a point where the weight of the string rivals the weight of the kite. Not only the weight of the kite, but even the updraft buoyancy of the kite. And when that happens, the string becomes a burden to the kite, and the kite will not continue to ascend. That's a problem. So, but your kite could be one mile long. Yeah, if you had a really huge kite? Yeah. Oh, yeah. A super kite. Oh my gosh, you take it up to the stratosphere. Oh my gosh. Yeah, okay, so say you have a one mile long. Yeah, the problem is in the stratosphere, wind speeds are about several hundred miles an hour. Sounds good. Sounds like a super fun kite ride. So basically, if you had a mile long kite, tied it to your foot, got it up there, you would just fly. So it would be fun, but temporary. The stratosphere is a little higher than a mile up, but yeah. No, I mean the, sorry, the kite itself though, the one square mile would be the size of the physical kite. Yeah, yeah, yeah, so, and you can put that up really high. Okay, good, I now have a new summer project. And by the way, it's a good way to think about physics problems is compare one thing going on to the other and you don't even have to get a number, you don't have to be numerical about it. How high can the kite go? As high as the weight of the kite versus the weight of the string. You just think about it in those terms. So traditional kites wouldn't be enough, but a super kite that you and I made. In fact, if you tried with your kite, you will see there's a point where the string starts getting saggy compared with the ability of the kite to keep it buoyant. And the kite just gets farther away from you rather than higher up. I feel like you would win a kite contest. Like if there was one and someone had to build one, I would definitely put you on my team. All right, here's a question. I was gonna skip it because it's long, but because it's Buck Rogers and that's something I love. I'm just going to ask it. Watching an episode of Buck Rogers from, oh, this is Ray, by the way, Ray Bamer. All right, watching an episode of Buck Rogers from 1979, Tweaky is missing. The subplot was transferring 10 million tons of frozen oxygen from space to the North Pole where it would melt and replenish the oxygen depleted atmosphere of the planet. The quote, space burg has to hit a window in our atmosphere exactly or be ignited by friction and scorch a third to a half of the planet. My question is one, would an, I know, would an injection of frozen oxygen or anything from space help Earth and B, could a space burg of oxygen scorch the Earth? Okay, so a couple of things. First, a burg, actually German for mountain, so it would just be a oxygen burg. Yeah. But space burg would be a mountain of space, if you want to totally analyze this. I will let whoever wrote Buck Rogers know that they have made some terrible word mistakes. No, iceberg is a properly named object. Yeah, yeah. It's a mountain, it's an ice mountain. So here's the thing. Earth has no shortage of oxygen at the moment. We just have too much carbon dioxide. We don't have a shortage of oxygen. If you wanted to just simply add oxygen to the atmosphere, what will happen is fires that are ignited will not burn out as easily as they might today because oxygen feeds fires. So let's say we have twice as much oxygen as we do today and a lightning strikes a leaf. And ordinarily, the leaf would just sort of ignite but then fizzle away, not with more oxygen in the atmosphere. It would totally come to flames. It would catch to another leaf and you would burn forest like it was nobody's business. So a space burg made of oxygen is what you would describe as a very bad idea. That would be a bad idea unless we're actually for some reason losing our oxygen and you have to replenish it. Right, and what we're gaining is carbon dioxide. We're not losing oxygen. It's two different things. Correct, now we have plenty of water. We don't need to bring oxygen from space. Water is what, chemically? Hydrogen and oxygen. H2O. Yeah, yeah. So you just, you break the hydrogen away from the oxygen and you got free oxygen. You don't have to go to space for it. Yeah, so maybe the Buck Rogers writers didn't know this. Yeah. Plus oxygen itself is not flammable. It only allows other things to burn. Right. So when they say don't smoke in your oxygen tanks, you're not gonna burn the oxygen tank. The oxygen tank is gonna burn you. Right. Okay, you light a cigarette, the cigarette burns instantly and then the flame, the spark hits your finger, then it burns your skin and then it burns your clothes, okay. Yeah, it would explode. Yeah, and this is how we lost three astronauts in Apollo 1. Oh really? It was a pure oxygen atmosphere inside their capsule on the launch pad, on a practice launch pad as they were testing communications and other things and a spark inside the spacecraft triggered and everything burned inside the spacecraft. Okay, but they didn't like light a cigarette. They were in foolish. No, no, they were not smoking astronauts. Yeah, yeah, well you said that's what happened and then you were, and then, but now I realize it's a spark. No, it's good. All right, what else you got? Here's a question from Alex Robinson about the Death Star. In the movie Star Wars, thanks for clarifying, we see the Death Star blow up the planet Alderaan. Setting aside the question of how a thing would be possible, what would happen to our solar system if the Empire blew up, say, Mars? Yeah, that's a great question. So it's really simple. First, how would you wanna go about blowing up a planet? What you can do is look at what's holding the planet together. There's all the gravity and there's all the tensile strength of all the solid matter that is the planet. And when we come back, I'll tell you how to blow up that planet. StarTalk Radio Cosmic Queries Edition. We'll be right back. Thank StarTalk Radio, Eugene Mirman with Mean Studio Live in New York. Eugene. Hello. Yeah, you're reading me questions. I've never seen any of these questions before, and we left off. Somebody wants to blow up Mars. Yeah, yeah, someone's basically like, if the death structure blew up Mars, what's a good way to blow up Mars? Yeah, yeah. How do you do that? What would it do to our solar system? Coley, okay, so here's how to blow something up. You ask yourself how much energy is keeping it together. Then you put more than that amount of energy into the object. It will explode. So more than the gravitational. Yeah, so you find out, you can calculate that. That's physics 102, not physics 101, 102. Is how to blow up Mars. That's a pretty, that's quite an accelerated scientist class. So you calculate what's called the binding energy of the planet, all right? And it's a gravitational binding. It's gravity keeps it together. You wanna overcome the gravity that's holding it together. Calculate that. How much energy is it? Now you have a device that can pump that energy into your planet and have that planet absorb the energy rather than have the energy come out the other side. It will completely destroy the planet to smithereens entirely. So that's how one would go about it. If you did it to Mars, we'd lose our Curiosity Rover that's discovering science there now. But it wouldn't affect us that much. I would affect our Rover. No, no, of course we would. Not tax money, excuse me. I mean our physical wellbeing, not our mental, emotional, knowledge wellbeing. We will continue to orbit the sun and Mars will have essentially no effect on us. Will parts of it land here and people will then gain powers? There will be Mars debris scattered all over the solar system. Mars debris will land everywhere. Yes, eventually it'll land everywhere. And would it radiate kids and make them powerful? No, cause Mars is not radioactive. Oh well, at least we get some of it. Okay, here's another question from Saar. Planetary death in the movies. Can I back up for a minute? Yeah. When you make a snowball, how much effort did it take to make a snowball? Well, not much, right? Not much. Not much at all. And then you throw it at the wall, it explodes on the wall. You don't think of it as an explosion. I do. But it doesn't bounce off the wall. It completely shatters on the wall. That's an example of the energy of motion of the ball, of the snowball being greater than the energy that's holding it together in the first place. Yes. And so you explode a snowball by throwing it into a wall. I would love to throw Mars into a wall and watch it just go everywhere and not irradiate anyone. There you go. Okay, planetary death in movies. Which is the most scientifically accurate death destruction of a planet you've seen on the big screen? How many? Okay, so two things. The Death Star planet, if it can pump the right amount of energy into a planet, it will blow up a planet just the way it's shown. Yeah. Okay, with all debris scattered. That was pretty accurate. That was accurate. That's probably the most scientifically accurate part of Star Wars. That was accurate. That and Yoda. Now in the red matter droplet in Star Trek, the JJ. Abrams Star Trek, that one holding aside. The unlikeliness of red matter. If you turn a planet into a black hole, it would become a black hole just the way they, essentially the way they showed it. So that's sort of accurate. It's implosed into itself. Assuming that red matter creates tiny black holes, that is a great plan. Exactly. But would you need to drill it into the center if you just put it at the edge? Don't get me started. Oh, sorry. Oh boy, okay. Once the red matter is into the surface at all, it won't know that it's at the center. How is it gonna know it's at the center of the planet? It has no idea. Well, yeah, no, they don't make it seem like this is the red matter's plan. They definitely make it seem like a Romulan idea, but Romulans, what do they know, right? Exactly. And then the other deaths of planets, Superman, I guess the new Superman, it implodes, and then the old one, it exploded. No, no, yeah, well, it's destroyed from within. Yeah, yeah, that's more realistic. They overmind the planet. So here are people who have superpowers and super everything, and they don't know that they're overminding their own planet. I don't know, can you think of any analogies? And they can send the baby Superman Moses style on a basket, a spaceship. So anyhow, yeah, that could happen if you. Are you telling me that Superman is unrealistic? You can destabilize a planet if you make Swiss cheese out of its innards. That's clear, but I like the Star Wars destruction. Just a good old fashioned planetary explosion. Put some energy into it, blow it up. All right, here's a question. Crowdsourcing science from Ryan LeBee. With the popularity of crowdsourcing, Kickstarter, Indiegogo, why haven't scientists taken to the internet in the same way? Why can't we get a mission, say to Mars, by crowdsourcing true science geeks who would love to support in a big way? If Veronica Mars can do it, so can the real Mars. Yeah, I think the problem is, well, there are two things. There's using the internet and having people participate in data reduction. That's just sort of another efficient way. And then getting people to sort of contribute to make a mission happen. Space is expensive. Far more expensive than your laboratory science experiment. That's all, it's a matter of scale. It's billions of dollars. Billions and billions of dollars. Not three million. Right, so if you want to create the budget to do real space things, it's not millions, it's billions. And it's a whole other scale. That's why. Gotta take a break. When we come back, more of StarTalk's Cosmic Queries edition. We're back on StarTalk Radio Cosmic Queries Edition. This, the last segment, we traditionally have our lightning round, because I take so much damn time answering all the other questions. The other questions are so involved in telling you the episode and what made them think of it. So, lightning round, I'm gonna pretend I'm in sound bite mode and we'll test our bell. There we go. Eugene, you're here for me. Yes, I am. Let's do it. Let's do it. Eric, he's got a question. Could an alien species consist of only thought or energy? Nothing we would recognize as body or mass? I don't see why not, except, oh, by the way, mass is energy, energy is mass. So I can imagine an alien species that is energy. I can imagine it. Make a pound of energy. I can allow my brain to accept the possibility of it. I don't know how to portray it. I don't know. But since matter and energy are equivalent, I think we're good here. Okay. The problem is energy. It's hard to create form out of energy. When energy becomes matter, you can make molecules and things and objects and brains and this sort of thing. Without it, it's amorphous and it might be harder to make amorphous life than material life. Next. Could you eat it though? Could you eat a being made of energy? Okay, acceleration. Actually, since the only point of humans eating is to give ourselves energy and nourishment, if there is an alien that is made of energy, you wouldn't have to eat it, you just have to absorb it. Okay, great. I'm on it. Acceleration of expansion of space to see, that's the, okay, Justin, his is his question. Is the expansion of space accelerating? If so, will that acceleration reach the speed of light? If so, what happens when it reaches the speed of light? It's accelerating and over time, it will one day exceed the speed of light, which it can do because it's expanding space, not objects moving through space. This is allowed by Einstein's General Theory of Relativity, published in 1916 by Albert Einstein. And in so doing, as the universe expands faster than the speed of light, the objects that it puts beyond that horizon will forever then be visible from your view. So the very distant future, all galaxies will accelerate beyond your visible horizon and the nighttime sky beyond our galaxy will go dark. And our entire known universe will just be the stars in our nighttime sky. Sounds fine. It's still pretty far. And all that we know of and what we call cosmology will no longer exist because there'll be no information about the rest of the universe other than the stars that are sitting in front of our nose. Oh. Next. Okay, Justin wants to know, lunar terraforming. If we terraform the moon, would nights be darker due to the lost surface reflectivity? Oh, almost anything you do to the moon will make it reflect more. The moon is one of the worst reflectings. Even adding skyscrapers? The moon reflects like a sidewall tire. The moon is like, I forgot then, it's like 5%, low, single digit, reflective. What if we covered it in mirrors? Would that be helpful? What would happen to the earth? So for example, earth, which has oceans and land and clouds, earth is like 10 times more reflective than the moon is. And so the moon is a bad, it's like dark. It's just so much light pouring. It's like as reflective as a pancake. Yeah, well no, it's as reflective as the surface of an iron skillet. Oh. So anything you put there is gonna make it more reflective if you want to terraform it. I can't even believe we can see it because of how non-reflective iron skillets are. Well, it's most because how bright the sun is. Sun is very, very bright. Exactly, so when you do this, if you want to terraform it, you will make the full moon brighter at night. Oh, really? All right, if the universe is expanding, can we use the direction of expansion to determine the center of the universe, AKA where the Big Bang occurred? It is expanding in every direction, therefore there is no center. And the best analogy I can think of is if you inflate a balloon, everybody on the surface of that balloon is expanding. But you can say, where's the center of the surface of that balloon? Where's the center of Earth's surface? If it's a balloon shaped like a rabbit, now you're assuming it's harder. Yeah, so there's certain geometries where there is no center, even though it can be expanding and the universe is one such shape. Great. What is the minimum size for something to be labeled a planet and why is it that Kepler 37b, which is only a fraction larger than Pluto, has been labeled as an exoplanet while Pluto was demoted to a dwarf planet? Yeah, so a couple of things. In the 2006 definition of a planet has to be large enough for its gravity to make it a sphere. Pluto checks out on that. Kepler checks out on that. Fine. But it also has to be significant enough with its gravitational attraction to have cleaned out its environment in which it orbits. And Pluto has done no such thing. It orbits in the Kuiper belt of other icy bodies in the outer solar system. Pluto, dwarf planet, Kepler planet, real planet, there you go. So just get over that. So Kepler is not covered in ice? In an icy belt? You could be covered in ice, but we don't- Of surrounding you. Yes, exactly. Next. Okay, quick. If a quasar of- Lightning round, go. Stars in its distance. If a quasar or a star is billions of light years away, how do we calculate that distance if light takes billions of years to reach us? Ooh, because the universe is older than that and we've waited around for it to get here and it finally got here and the light that reaches us is light that left that quasar back at the beginning of the universe. So, the stuff that sent us light that hasn't gotten here yet, we don't see those objects. But we will. We will eventually, as the universe gets older, those objects, we will see them being born. They will rise up out of the firmament of the cosmos and their light will show up to us and we'll say, there is an object being born now that the universe and our cosmic horizon has enveloped their existence. And the universe is old enough for its light to reach us. We gotta go. Thanks, Eugene, for being part of Cosmic Queries. You've been listening to StarTalk Radio. I'm your host, Neil deGrasse Tyson. Thanks always to Eugene Mirman, who does such a great job with me. As always, I bid you to keep looking up.