Did NASA accidentally invent a warp drive?

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Speaker 1: Hey, Daniel, what's your first reaction when you see a dramatic science headline? M M, I guess it's a superposition of excitement and skepticism. The quantum reaction. What do you mean by skepticism is part of you assume the study is not real? No, it's more skepticism because I think the news coverage might not be fair. Wait what he's saying? The news media is biased. I get this constant stream of articles sent to me by listeners who asked me like, is this for real? Can I believe this headline? But somehow I believe you. Well, I think we've earned more trust than some of those websites called like coffee or die dot com or link zilla dot org. I've never been to those sites, but thanks for the reference. I'm always looking for ways that Icetein was wrong. I hear there are ten reasons you won't believe the seventh one. Hi am more handy cartoonists and the creator of PhD comments. Hi, I'm Daniel. I'm a particle physicist and a professor at UC Irvine, and I'm dying to find out why Einstein was wrong. You're dying to find out you would give up your life find out why Einstein was wrong. I guess it's more figuratively dying to find out. But I do get a lot of emails from people who say they have figured out how Einstein was wrong, and every time inside me there's this little flash of hope. Maybe this is the person who has figured it out. Yeah, you never know, right, I mean, Einstein was just some dude working in a pen office, and he figured out that everybody else was wrong. Einstein was a very smart dude. But yes, you're right, he was just a human being with a human brain thinking about the way the world works and coming up with a more beautiful and more compact and more effective description of reality. But we're also pretty sure his ideas weren't the final ideas. So you think he is wrong. I'm very sure that Einstein is wrong. I just don't know who's right. So what do you do with those emails? Do you a fact check them? Do you go through them? Yeah? Absolutely, I read them. I scan through them. I give them some feedback on the science. Do you encourage them to submit it to a journal or at least a coffee or died dot com. Most of them aren't really in journal ready format yet, so I give them some tips about how they might get there. I see you give them a tech or word processing tips. Welcome to our podcast Daniel and Jorge Explain the Universe, a production of I Heart Radio in which we try to figure out how Einstein was wrong and also how he was right. Our goal is to explore how the universe works, to wonder about all of its crazy mysteries, those fundamental questions about the very nature of reality, what rules all those particles are following. We want to weave them all together into a deep and beautiful understanding of this cosmos, and we want to explain all of it to you. That's right. It is a vast universe full of mysteries, and our understanding of these mysteries is constantly changing. Science is not a constant thing, and science is not done, still working hard to figure out how things actually work, because the way we think it might be working doesn't always pin up. That's right, and it also doesn't make progress in a steady fashion. It's not like every day we get five more units of science. There are moments in the history of science when somebody has a flash of insight, when years of struggle finally coalesced into some progress and we make a great leap forward in our understanding. And you never know what day is going to be one of those days. Yeah, everybody tunes into the science news of the day to see if a great new discovery has been made, or if scientists figure out how to do some amazing thing, or if it's just linzila dot org spamming us again, giving us clickbait. But there are always interesting news headlines, sometimes on the on the regular news, and sometimes they spill over onto the mainstream media, right, Yeah, And sometimes they seem like click bait, but they are real. You know, scientists measure gravitational waves, ripples in the fabric of reality. That sounds like it was made up by a copy editor working in a basement somewhere, but that was real. Yeah. Science does make a lot of progress, and people are excited when something really big happens. But sometimes those headlines are a little bit overblown. That's right. You can't believe everything you read in all of the popular media about scientific progress. Sometimes they're just trying to get you excited and make you click on their link. We had a whole episode about how to critically read popular science articles, the upshot of which was develop a few sources of information that you really trust and check those Wait, wait, are you trying to tell people that you're the only person they can trust? Is that what it is? Isn't that how how cults work? I do think we are a pretty reliable and even handed source of information about science progress. But there are other places you you can get your science news. I like the coverage in the New York Times and in the l A Times, and also in Quantum Magazine, often very insightful and always very well informed, but also false and non informed at the same time. Because it is a quantum magazine, they try to deliver one quantum of understanding at a time. But there's a lot of information and news out there, and it's kind of like you say, it's hard to figure out what is real and what is not, or maybe what is real but exaggerated. I think that's maybe a lot of what happens in these news headlines, right, there's like some neggat of truth, but they sort of emphasized the extreme interpretation of these things. Yeah, often they have removed the coffee AATs and the qualifiers, and so you know, somebody does like a simulation of a black hole universe on their computer one afternoon and writes a paper about it, and then the news headline is like graduate student plunges entire universe into a black hole or something similar. Well, that's probably only exciting for that gratitude. Well, you have a whole ted talk once. I think about the scientific news cycle and how this happens, how real scientific research gets sort of filtered and amplified. Yeah, and then how it all comes back to your grandma and how she ends up wearing tinfoil hat. So we do think it's very important that everybody out there have a sense for what's real and what's exaggerated. So when a bunch of listeners all send me the same article, I think maybe it's sound to do an episode about one particular piece of research. Yeah, and then months later the episode comes out. Sometimes we rush it right. Sometimes we if it's a hot topic, we'll ask my hard to put it out quickly. That's right. We do sometimes try to be responsive to the real world. And so recently there's been a pretty incredible sounding headline that a lot of people wrote to you about. Right. I guess people look to you to know if something is overblown or real, because I'm certainly not getting those emails. How do you know? Are you reading your emails these days? But every morning in my inbox I certainly get a pile of email from listeners who say I saw this headline? Is this real? Or could you do an episode explaining this to me? Because I still don't understand it. Yeah. Pretty recently there's been a pretty exciting sounding headline about warp drives and NASA. To the question we'll be technic today is did NASA just accidentally build a warp drive? Nathaniel? Which part is maybe not real? The accidental part? Did they build one on purpose? Actually, let's see the parts about this headline. They're not real, are the NASA part, the accidental part, and the warp drive part? So they did build something? Did build something? No, they didn't even actually build. So let's see which works are left here? Um might have did something? Might have happened. So I'm looking at a web page from Coffee or Die dot com and the headline is DARBA and NASA scientists accidentally create warp bubble for interstellar travel. There's no might or maybe, Well, we'll dig into this headline, but first, we were wondering how many people out there had her about this or think it's real. So thank very much to everybody who volunteers to answer these questions for this section of the podcast. We really appreciate you speculating about things you haven't had a chance to prepare for, and hope everybody else out there enjoys them. If you would like to participate for future episodes, please don't be right to me. Two questions at Daniel and Jorge dot com. So think about it for a second. Do you think Naha just accidentally or on purpose build a warp drive? Here's what people had to say. I'm pretty sure they did not discover a warp drive, only because that would be pretty big news, and as far as I know, I've heard nothing about it, so I'm gonna say no, No, they definitely did not accidentally discover a warp drive. I would love that to be true, but I'm pretty sure that's not the case. Since you're asking, I think the answer is yes, but I haven't heard about it. I don't think that's I can do mistakes like this, at least not now, probably in the future. But I don't think this accident just happened. I don't know, but I kind of hope so, because I think that would be amazing to be able to travel really far, really fast. All Right, a lot of excitement and either way, people are like, I don't know, but that sounds awesome. Yeah, just like me. Everybody wants this to be true. And I think that's one of the reasons that these articles are successful is that it touches the excitement inside people. People are hopeful for this kind of leap forward in technology. Yeah, I mean, I guess at least the people who read Science News probably also are fans of Star Trek, and so that that's where kind of maybe the idea of warp drives first god spread into the popular culture, and so people are excited for this to happen because a lot of exciting things happen in Star Trek. You think people are more excited about warp drives or like the holidack. Well, the holiday already exists, Daniel. You have a holidack. It's called the metaverse. Well, that's right, and we recently took a trip to the metaverse, so we should know all about it. Yeah, it's nice and cozy there, But war drivece would be pretty amazing, right, because they would let us travel to other stars and their planets and maybe other galaxies. It would be really incredible because one of the disappointing things about the universe is that it's so big that everything is so far away. We're limited to travel slower than the speed of light, which seems really fast, but even in comparison to the vast distances between stars or between galaxies, it's not really fast enough to get us interesting places in the reasonable amounts of time. So a warp drive would be a wonderful way to like zip around the galaxy or the universe and just learn so much about what's going on out there. That would be super cool. Although Daniel, I feel like you shouldn't be disappointed at the universe for for being so big. That feels a little mean, you know, like maybe it's our fault for not being fast enough or big enough. Yeah, maybe disappointed is too judgmental. I'm just frustrated. I feel like there's information out there. You know, there are either aliens living on other planets and crawling around of those services or not, and the facts are out there. They either are or they aren't, and we could know it if we could just like get there and see these things. But everything is so rustratingly distant. It's like somebody has answers to the deepest questions about the universe, but they're keeping them in a locked box and you can't see them. Yeah, unless you go to coffee or die dot com. They seemply have the key. It would be pretty cool, and it is pretty prevalent in science fiction movies warp drives because I guess it solves pretty much any plot that the problem that you might have in setting up a space story, right, because without a warp drive, you pretty much can't have any space stories because it would just take too long to get between planets or between parts of the galaxy. What's an interesting question with a few nuances. I mean, in one hand, you can't realistically have like a galactic empire. You can't make decisions for a set of stars that are many, many light years apart, because when you make a decision, it takes like years and years even for that information to propagate across the galaxy. Or how can you like move your army from one star to another, or gather resources in one place and move them somewhere else. It really effectively limits you to operating in a single soul or system. Yeah, Like even just to send an email to the other side of the galaxy would take a hundred thousand years, right, that's right, So you can't really coordinate across different parts of the galaxy due to the speed limit of the speed of light. But you know, if you're patient, you could send out explorational teams which could discover those other star systems, so you could realistically still have like first contact stories, but you can't zip back and forth between stars that are really far apart. I wonder if it just maybe our point of view about time, Like if we live to be a million years old, you know, maybe a hundred thousand years old to send an email wouldn't be that bad. Yeah, that's a really good way of thinking about it. The speed of light really is a relationship between time and distance, And so if time isn't much of an issue for you because you're gonna live to be a million years old, then the universe is a lot more local than if you live very short lives like we do. Well, regardless of how old you live, having a war drive would be pretty handy for exploring the universe. For sending emails to the other side of the galaxy. And this headline that people are sending and you seems to say that NASA may have accidentally build a warp drive. I wonder wh where the accidentally comes from. Are we going to cover that. We are going to cover that. Absolutely yes. So it's a pretty tantalizing headline. And so let's dig into this idea first of all, and let's start with the basics. Daniel, what is the technical definition of a warp drive? So a warp drive sounds like science fiction because we hear about it in science fiction, and usually you hear scientists saying that it's impossible that you can't go faster than the speed of light. And so a warp drive just sounds like, you say, a science fiction plot saver a way to just like dot dot dot your way to distant stars without worrying about the limitations of the speed of light. But in the last few decades, there has been a lot of progress in imagining how we might build a warp drive using actual science, using real technology. It's not like we have plans for a warp drive right now, but we have sort of a direction that theoretical physics points as towards that suggests it might be possible. What are you saying that NASA has accident proven that warp drives are possible. I'm saying that we're like step one out of three million towards building a warp drive. Are you saying that NASA has taken the first steps towards building a war drive? There are some theoretical physicists that have laid the foundation, yes, which may eventually lead to actual warp drives being constructed. What are you saying that that's I will eventually build a war drive. I think you've had too much coffee or die this morning. No, I'm just kidding. Let's maybe be super clear about this, right, this is an idea where you have something aboard your spaceship, right, and this device that you have on your spaceship somehow, let's you cut through space, right, or go faster than the speed of light. That's the idea of warp drives, right, Because it's maybe different than like the warmhole gate that some science fitch and stories used to go between spots in the galaxy. Yes, so you do have to follow the rules of relativity. And the cool thing about the warp drive is that it does follow the rules of relativity. We're used to relativity telling us that you can't move through space faster than light, and that doesn't change. We can't avoid that. But relativity also tells us that space isn't just flat, that it can do weird things, that the relative distances between points in space can change. When we talk about space curving or bending, that's really what we mean. We're changing the relative distances between points. Remember that space isn't like relative to some external rulers, So when we talk about the distances between things, these are really just intrinsic bending of space. You often see this rubber sheet analogy where somebody puts like a bowling ball on a rubber sheet and it bends the rubber sheet. That's helpful for thinking about bending, but it's also quite misleading because in that example, the rubber sheet is bending in relation to some third external dimension. Here, were really just talking about changing the relative distances between points in space, and that's something that we know can happen. That's something that we have observed. We see it happen in gravitational waves, which are ripples in space. We see it happen in gravitational waves, which are ripples in space. We see it happening in the expansion of the universe, which is increasing the relative distance between it's in space. So there was a guy named al qb Air a few decades ago who came up with a sort of arrangement of space that would allow you to move like a chunk of space relative to other bits of space to sort of like create a warp bubble which would itself move relative to space. So you could sit inside that warp bubble and it would transport you to your destination. Yeah, there's this idea. I guess that space is not like empty and immovable and fixed and super stiff or or rigid, but space is kind of squishy, right, like for example, black hole sort of squishes the space around self, bending space and maybe creating some weird kind of shortcuts through space. Yeah. Einstein's big idea was that the whole concept of gravity is not a force the way Newton imagined it. It was just that things move in response to the shape of space. That space has a shape, it's not just flat. And so because we can't see that shape directly, like you can't look at space and say, oh, I see that it's curved, but we can see how space changes the motion of things that go through it. We discover that gravity is just like an apparent force. It looks like there's a force on stuff, but it's really just stuff moving through curved space. And you can do much more than just curve so that the Earth goes in a circle around the Sun, for example. It can ripple like gravitational waves, and it can expand like dark energy, and it maybe even more amazing things like warp drives and wormholes. Yeah, you're saying that scientists in recent years have taken these ideas about relativity and figure out maybe a way that you can make a warp drive using relativity. And it's specifically something called a war bubble that might let us use it to actually get to other places in the galaxy or even the whole universe. And so let's get into the details of this warp bubble. But first let's take a quick break or I we're talking about the headline NASA accidentally build a warp drive part of Yes, you know you are giving too much credit to this headline. It's not asking the question did NASA, It says NASA scientists accidentally create war bubble for interstellar travel. What did they say might have or did they actually did it? It says they created it. That's what the headline says. Well, we are digging into this headline to see if it's true or not. And we've talked a little bit about what a war drive would look like and what it would be, and it sounds like so far scientists have only come up with one possibility for making a warp drive, and that is to make a war bubble. And it's based on a special concept you were talking about. Yes, So a few decades ago, there was a gravitational theorist, Miguel al Kubier, who said, what if you could bend space in a very particular way, And so he took a spaceship and he bent space around that spaceship so that the space around the ship itself was flat, but then there was a bubble around the ship that moved that flat space through space is itself. So it's like you take a chunk of space and you sort of slide it through other space and so that you can just sort of sit inside that bubble and then you get to your destination and inside the bubble, you don't feel like crazy acceleration or anything. It just feels like you're sort of floating there. So his question was, like, what shape of space do we need in order to accomplish that? And the cool thing was that he figured one out. He figured out a way to be consistent with Einstein's equations and also compress space in front of this bubble and expands space behind the bubble, so the bubble effectively moves relative to the rest of space. Yeah, I know we've covered this in our book, maybe both books. We can. We ask questions about the universe and we have no idea and this, I have to say, this always kind of puzzled me a little bit. So maybe let's step people through it. So the day is that you're on your spaceship during space and you flip the switch or you pull the lever forward on your warp drive device, and what it's doing, you're saying, is that it compresses this space in front of you and it expands the space behind you, and somehow that moves you through space faster than the speed of light. Remember when we say compressed or expand we're not like making space more dense or anything. What we're doing is changing the relative distances between points. That's what general relativity in Einstein's equations do. They start from a certain distribution of matter and energy, and they say, if you have a blob of stuff here and a blob of stuff there, how will space curve? What are the relative distances between any two points? So that's called the metric. The solution to Einstein's equations is the metric, which is just another word for like how to space curve, or another way to think about like the relative distances between two points. So Alcubier's warp bubble says, is there a way to shrink distances in front of this warp bubble and expand distances behind it? Okay, so let's say I'm in my spaceship, I'm orbiting the Earth, and let's say you just want to take a short hop over to Jupiter. So I engage my warp drive, I pushed the lever forward, I put on my seat belt, and suddenly the space in front of me between me and Jupiter, instead of being millions of miles, suddenly it's three miles. Is that what you're saying, Like, somehow I am affecting the space between me and Jupiter, so that what used to be billions of miles is now just a few miles. Is that the idea? That's the idea, and that only works for me or for anyone like caught in the middle or anyone who hops in behind me. Do you know what I mean? Am I just affecting the space relative to me as an observer? Or am I actually affecting the space between here and Jupiter? So it works for anybody within the war bubble. It creates this sphere around the spaceship, and that sphere then gets slid along through space, so it sort of gets moved, so it gets rearranged. Its relationship to the rest of space changes, right, It's now closer to Jupiter and further from Earth, and so anything inside that war bubble has the same experience. Does that mean that the bubble needs to encompass Jupiter? Or am I just compressing the distance between here and the edge of the bubble? Inside the bubble, everybody hangs out and SIPs their coffee. The bubble's edge is where space is being compressed, So between the bubble and Jupiter space is being compressed, that distance is being shortened, and between the other edge of the bubble which is sort of behind you, that space is being expanded. What if there's something right in front of me outside of the bubble, but between me and Jupiter, Like let's say there's a satellite there or an old Grammar crossing this interstellar street, Like, what happens to that person in between? Did they get squished or do they not even see this, this bending of space that's happening to me or to my bubble? Yeah, this would be bad news for space Gramma for sure. I mean this is very destructive changing of the shape of space. Basically, anywhere between your warp bubble and Jupiter and the same thing between you and behind what get squished? It would get squished absolutely. Oh so between so I mean a bubble, let's say invent bubble is the spaceship. So anything inside the specip is normal, anything outside gets bent around, and so the space between the spaceship and Jupiter gets compressed. And but then wouldn't that affect the other planets as well? You're saying anything caught in the middle will get squished, But would it affect like the orbits of planets and everything else in the near vicinity of your ship? It certainly does affect things. So things in your path definitely do get affected, So you know warnings to all the space. Grandma's out there taking a walk, and anything very close by is going to get affected. But the shape of the work bubble is quite tight, so it doesn't like affect the gravity of things very far away. Well, let's get into what would happen to Grandma she gets like squished flat or or what or would she even noticed because you know, she's spaces just changing her runner and so her molecules also change space. Grandma would be very unlikely to survive this encounter because the space she's in its metric would be changing, and so that's likely to tear her apart. Changes in the shape of space can have an effect on the objects in that space. That's how, for example, we discover gravitational waves. We see that space is shaking a little bit, changes the relative distance, for example, between mirrors that are hanging underground miles apart, and so you probably don't want that to happen to your space. It's happening all the time right now. Space is expanding out from under us because of dark energy, but it's very very gentle, and our molecules are powerful enough to hold ourselves together. If that was much more rapid, then you would get torn apart. And so that's what's going to be happening behind the work bubble, and the opposite is what's happening in front of the warp bubble. So yes, that will be quite destructive. I guess that's why you need crosswalks even in space. So then the space in front of me between here and Jupiter suddenly goes from a few million miles to two miles. And then you're saying the space behind me. You know, I was an orbit around Earth, but now suddenly the space behind me, me and Earth goes from a few miles to a few million miles. Is that the idea? Exactly? And that's basically travel, right. You've gone from far away from Jupiter too close to Jupiter. Yeah, But then I guess what's the next step. Do I then move the few miles and suddenly I'm in Jupiter? Or do I just turn it off and suddenly I'm there? Yeah, you just turn it off. I mean your goal was to get close to Jupiter, right, So you've rearranged space and now you're close to Jupiter, right, you're two miles from Jupiter and two million miles from Earth instead of the opposite. It is weird because I compressed space in front of me, but don't I need to expand it again. Remember that compressing space is changing the relative distance, right, So that is already accomplishing your goal. Right. Your goal is I want to be close to Jupiter and far from Earth. And so that's what the war bubble has done for you. It's rearrange space so that now you are close to Jupiter and far from Earth. It feels kind of like magic, like you just said, like, hey, I want to be there, so you're there. It's not exactly magic, but it's also not exactly science yet. I Mean, what al Kubire did was just say, is there a way to arrange space in a manner that still is a solution to Einstein's equations? Like do Einstein's equations prohibit this from happening? And the answer is no. What he didn't do is figure out how to make it happen. Like Einstein's equations go in one direction, they say, if you have this arrangement of mass and stuff in universe, what is the shape of space around it? Cool? And then how does things move in that space? What they don't do is tell you, if you want a certain shape of space, how do you build it? And so Alcubier just said, well, is it possible to have this shape of space? And Einstein's equations say yes, that would satisfy the equations, But it doesn't tell you how to arrange stuff in the universe to make space do that. That might be impossible, And in Alcubier's paper he discovers that the only way he could come up with to make this happen was to have some weird kind of matter that has negative mass or negative energy density, which as far as we know, doesn't exist in the universe. I see you're saying, Einstein's equations what we know to be true. We know it works, but it doesn't tell us that we can't do magic. Basic like, it tells you that it's possible to be here close to Earth, and it's also possible to be there close to Jupiter. Uh. And so technically you might be able to figure out a way to make those two things sequential in time very quickly. Yeah, And it's a little bit more than that, right. He did show that it doesn't violate Einstein's equations, which means space says, sure, I can do that if you assemble mass and energy in the right configuration to make me do that. I won't tell you how to arrange it, right, I won't tell you what the recipe is. But in principle, let's not off the table. So that's like a big hole in the argument. We don't know how to build this thing, but the universe's list of rules don't explicitly prohibit it. But what does the recipe? What does it actually say? You're saying it needs like negative energy or negative mass, And then what do I do that? Do I just put it in front of me? Do I need to lay it out between here and Jupiter? Do I need to you know, spit it out in front of me? You know? And like what does it say about how to use this or how you would need to use this negative energy? So since the original paper, there's been a proliferation of really cool ideas about how to do this and how to do it more efficiently. So far, every solution, every paper I've read, requires using some kind of negative energy density matter behind you in order to expand space, and some sort of positive energy. The entity matter of like normal matter like me and you in front of you to compress space. So basically you have to build a track of matter in front of you that compresses the space, and then you have to have negative matter behind you to expand the space. So I do, I do have to lay out the whole track, the whole highway for the world drive to work. And you need to have positive energy mass in front of you and negative energy mass behind you. All right. We talked about this once on an episode about whether you could use a warp drive to escape a black hole. Basically, you have to build the track out of the black hole first in order for this to work. All right, So then I have to build a track. I guess I would have to build it. But to build the track, I have to get the Jupiter first. Yeah, exactly, Like you know, to lay out a highway between here and Jupiter, I have to go from your Jupiter exactly, huge caveat there. Right, you have to build this track somehow. I mean it's possible that somebody else could come up with another way to make space do this that doesn't require you to visit that place in advance and sort of be able to track along the way. Remember that Einstein's equations just say space can do that if you can figure out how, And now people are trying to be creative about figuring out how to do that, and so that's one obstacles, like laying this track in front of you. The bigger obstacle is that we've never seen anything with negative energy density before. We don't even know if that's possible to do in the universe. It sounds like it's more of a like a warp train than a warp drive, right, Like you kind of have to lay out the tracks or are you gonna be like those cartoons where you're like going and laying the tracks down at the same time. Leave it to the engineers to figure out some way to make this very effective. The physicists are just like, well, space says we can do this if somehow we can arrange a strange matter in the right configuration. Right. But as as the engineer, I would be mad if you told me like, hey, I can out with a way to make a warp drive, but it's actually a warp train, you know, and then then we brought all the wrong tools to make it. You'd be disappointed in a warp train. I'd still be pretty excited about warp train. I mean, you're right, it's not a warp drive but a warp train. It's still pretty awesome. Yeah, No, I think both. It would be exciting. But you know, if I'm gonna pay for a ticket, I want to know what I'm getting, or if it's going to be a train ride or it's gonna I'm gonna see some fancy star show. All right, So then it seems like it's it is possible, at least from a theoretical perspective, to make a warp something warp driver or train or I don't know, tram. Perhaps how about a warp zip line that would be pretty cool. Oh, there you go. So it seems possible. But the question is how you would make it. And there's this idea of a Casimir effect that might be able to do it, and that's kind of where where this headline all originated. Right, So what exactly did this study that the headline is based on do. This study is trying to make progress on the stickiest part of the warp drive or warp train project, which is negative energy density. Right. By energy density would just mean like how much stuff is there in a certain part of space. Matter has energy to it, right equals mc squared, and so if there's a lab of stuff in space, that's positive energy density. So the warp drives needs something with negative energy density in order to expand the space behind you. And so this project was trying to figure out like, well, is it possible to build things with negative energy density? And here's the accidental part. They weren't actually trying to crack this problem of the warp drive. They were just studying the Cassimir effect, which is a well known and actual thing which we have proven is real. And they were looking at the energy density of the Cassimir effect and they noticed something interesting to them, at least which they connected with warp drives. I see. So this is now jumping off from this idea of a warp train that you can compress space and expanded behind you. But to expand the space behind you you need negative energy. And so these folks were studying negative energy and you're saying they found something, but they did find something interesting, that's true. I mean, I've read their paper. What they were doing is studying the Cassimir effect, which is a really interesting and super awesome quantum effect that appeared between two play that are very very close together. So imagine two like two sheets of metal and bring them like ten nanometers apart. What you discover if you do that is that there's a force between them. Even if they have like no electric charge on them and we're ignoring gravity, you can measure this force which appears between the plates because of this strange quantum effect called the Cassimir effect. Okay, so what is this. What's happening in the Casimir effect is that we're actually interacting with and probing the vacuum energy of space. Remember we've talked about how space is not just empty, it is filled with quantum fields. Like there's a photon in space that's a wiggle in the electromagnetic field. There's an electron in space that's a wiggle in the electron field. But even if you don't have a photon, and even if you don't have an electron, space still has these fields in them, these possibilities for particles to pass through them. And because their quantum fields, they can never actually go all the way down to zero energy. There's always a little bit of fuzz, a little bit of energy. So we call that the vacuum energy, the lowest possible energy in the quantum field, which is not zero, And so people wonder like, is that real, is it really happening or is it just like part of our mathematics. Well, the cool thing about the Casimir effect is that when you bring these two plates really close together, it cancels out some parts of those wiggles between these two sheets. Only certain kinds of wiggles can survive, so it suppresses some kinds of wiggles and allows others. And so because it's suppressing some kinds of wiggles, it like lowers the energy between these two sheets, which creates an energy differential, which is what creates a force. So it squeezes these two plates a little bit closer together because that's a lower energy state. So the Casimir effect is like deleting some vibrational modes of the quantum vacuum between these two plates in a way that ends up pushing them together a little bit. Right. It's sort of like you create a space that is so small that most particles can even fit in them, and so the universe can't create those particles in that space, and so therefore it like it creates almost like a void in space, right where like nothing can happen there, So there's sort of like an emptiness and the rest of the universe is biased towards having a little bit of energy. Then that vacuum somehow creates like a it sucks stuff in. Basically, it's really fascinating because it lowers the energy of space there below the vacuum energy. Right, typically we think the vacuum energy is the lowest, but if you create this special configuration, you can bring the energy of space below the vacuum energy, as you say, prevents those fields from existing in certain modes, and so it lowers the overall energy. You can either think about this in terms of fields, if you like thinking about space is filled with fields, or you can think about in terms of virtual particles, which is really equivalent, if you like thinking about space is filled with all these virtual particles constantly popping in and out of existence. Between these two plates, some kinds of virtual particles are not allowed, and so the energy density is lower between the plates. I see, so you're saying you're not creating a spot of negative energy, You're just creating a spot of lower energy. Then, like the normal amount of energy that the universe has sort of like sound, right, Like you can't have negative sound, but you can make a room that's lower sound than like the average din of the your space of your talent. Yeah, that's exactly right, and some really important nuances there. As you say, it's not really negative. Energy is just lower than the vacuum. Now, if you define the vacuum to be zero, then it's negative energy density, I suppose. But that's a little bit arbitrary, just sort of like where you set your zero. Really it's lower energy than the rest of space around it. It's as an interesting puzzle there because all the physical phenomena we observe this actual force from the Casimir effect. This just relates to the energy difference, like the fact that there's lower energy between the plates is what gets the force. But if you try to do the calculations and ask like, well how much energy is there in the vacuum, you actually run into weird infinities like try to calculate you say, well, there's an infinite number of different possible modes in space, and so in principle there should be infinite energy there, which gets really eared and still nobody understands. So we see the Cassomir effect. We know there's a lower energy density between the plates even in the Casimir effect. We don't really understand what the absolute energy is even in like normal empty space. We just know that it's lower between the plates and the Cassimir effect. All right, So we have this Casimir effect that might be able to give us negative energy, which might let us make a warp should you train? That's how I think scientists you call. So let's get into whether or not someone has actually made this Casimir effect work and whether it can be applied to a warp drive. But first, let's take another quick break. All right, we are warping our way to examining news headlines, and particularly a very specific headline recently that's that NASA might have accidentally built the warp drive. And the study that created this headline was actually looking at the Asimir effect, which is a way to maybe create zero energy or negative energy in the universe. Now, Daniel, this is a kind of a theoretical effect, right, something scientists think it might might happen if you run this experiment. Has anyone actually done this and measured this negative energy? People have actually measured the Cassimir effect, So Casimir predicted it in like by doing a bunch of calculations, and it's a very very small effect, so it took a long time and some real virtuoso experiments. But in n Stephen Lamereaux at Yale actually did this. He was able to measure the force between two objects that really really close together and found the forest was very close to what Casimir predicted, and that's been verified since then. Yeah, there have been other experiments that verified, and they've done it with various different configurations. It's really hard to actually do it with like two sheets that are like an animeters apart, so instead they use like one sheet and a sphere for example. Experimentally, it's just sort of easier to manipulate and at separations of like ten nanometers, which is like a hundred times the size of an atom, the Cassimir effect produces a force about equivalent to like an atmosphere of pressure. So you're saying we can create spots of negative or zero energy in the universe, and does that mean then that the space in that spot gets expanded like in an award drive like it would do an a warp drive. So we can create spots which have lower energy density than normal empty space, right, and it does cause the Casimir effect, and we've measured that and that's real. We don't know if that actually means their negative energy density, right. We don't know how to set the zero to try to calculate the energy of all the space. You get infinities which don't make sense, So we don't know how to do those calculations. So an open question about the Cassimir effect is what it means for gravity. Remember that gravity is a classical theory. Einstein's theory of gravity doesn't even know how to deal with particles, not to mention like an infinite number of virtual particles. We don't actually know how to calculate the impact of this kind of arrangement on gravitational fields and on the shape of space. We don't know the answer to your question of does this expand the space between those two sheets? But I guess in theory it is right because energy, in general it compresses space. So you have something where a spot where you have less energy than technically that space would not compressed as much, which would be the same as expanding space. It depends on whether the general relativistic concept of energy density is the same as the quantum mechanical one. Remember the quantum mechanical one. Here, we don't know if this is negative or positive energy density, and we don't know how to do those calculations because we don't have a theory of quantum gravity. People have tried to do those calculations and they get crazy predictions like oh, there's infinite energy here, so you get singularities everywhere in the universe, and so it's just sort of an open problem in theoretical physics, sort of gravitational implications of the vacuum energy. So you can create a spot of almost zero or negative energy, but you don't know if it's expanding or compressing space, but it is that if it is, and you could use it to maybe make a warp drive maybe, because we don't really even know if it counts as negative energy density and a gravitational sense. Again, it's just relatively lower energy than the rest of the vacuum. And so in this paper, what they were doing was thinking about the energy density from the Cassimir effect, and they were doing a bunch of simulations. So in this paper they didn't build anything right, They didn't like create a lab and build something. They were just doing calculations on the computer, thinking about what is the energy density between objects that are really close together, thinking about the Cassimir effects. That they were doing a bunch of calculations. So then what did they find in their simulations and why do people use that to make the headline that NASA created a warp drive. So they were doing a bunch of calculations and they saw a plot and I had these funny shapes in it. And one person who's working on the project is also really interested in warp drives and remembers seeing a similar shape in a paper about warp drives, and we said, oh, this figure here, this shape of the energy density looks kind of like the shape you would need for a warp drive. Well, maybe step us through with more detail here. What is there's a plot of just a plot of the energy density between two surfaces, Like in the Casimer effect, you bring two surfaces very close together and you get lower energy density between the surfaces than around it. Again, that doesn't necessarily mean actually negative energy density from a gr perspective, but had like an interesting shape and it had sort of the same shape as a figure from a warp drive paper. That said, here's the negative energy density profile. You would need to expand the space behind the warp bubble. So it just sort of like, oh, we have a crescent in this plot. We have a crescent in that plot. Maybe they're the same thing, but they're not at all, right, It's just sort of vaguely similar. And this is just a qualitative comparison of two things that might not even be related. It's just like saying, oh, the Casimir effect creates this crescent shape negative energy density. I also have a cookie of that shape, So maybe the Casimere effect makes cookies. Well, who doesn't want to warp cookie? But what's a little I feel like maybe it's a little bit more than that, right, because you know what they saw in this simulation. It seems like it is that if you bring these two plates together and measure the Cassomer effect, you get a dip in the energy between the two plates. Right, That's probably what they saw, like a dip in the energy. And if you plot the energy between the two plates, you'll see a dip. And he's saying, well, to make a warp train, you need to also kind of create this dip in energy behind you. You certainly do, but we don't know again if the Casomer affects relative decrease in energy density would actually create the kind of expansion of space we need for the work bubble, and the work bubble needs to sort of general relativistic negative energy density, which requires like particles of negative mass, for example, whereas the Casimir effect creates a relative shift in the quantum vacuum and we don't know the impact of that Gravitationally, all this paper is doing is saying, oh, look, I made a shape of relative decrease of energy density that's similar to the actual negative energy density in a warp bubble metric. Right, So then I guess what would be the idea is that you somehow create a whole bunch of these plates really close together behind you, and somehow that decreases the density behind you and somehow that compressive space. Is that kind of where they were going with this. That's sort of where they were going with this. But you know there's a lot of leaps there, right. First of all, Number one, this is just a simulation. Haven't built anything, haven't demonstrated that their calculations are correct. But you said that Cassimer effect has been proven experimentally. Yeah, the Casomer effect has been proven experimentally, but that doesn't mean that everybody who's doing Casimir effect calculations is correct. And this particular team has a bit of a spotty history in publishing papers. This is the same team that was working on the e M Drive, an attempt to build a rocket that violates Newton's third law, you know, propellant less rocket. So you know, you've got to take everything they do with a bit of a grain of salt. And they also haven't shown a really crucial step, which is that the Casimir relative decrease in energy density actually does provide the negative energy density you need for general relativity to create this wark bubble. They just have not shown that at all. So I passed this paper to an expert in a friend of the podcast and Baroxter Scheney, who's a professor of cosmology and gravitational physics, and his review was, this paper is a pure nonsense. How this paper passed pure review is completely beyond me harsh, I mean, let's not mince words. It's a pure nonsense. That was his evaluation. He was not very impressed with this paper. Well, from a theoretical point of view. Yes, I feel like from what I'm understanding here from you today is that, Yeah, they skipped over the fact that we don't have confirmation that lower energy leads to a expansion of space. But everything seems to kind of point to that, right, that's kind of how the universe works. More energy you have, more space gets compressed, I suppose. But we don't know how to do the calculations to predict the impact on the curvature of space of lower quantum feel the energy. Remember again that g R is a classical theory can't handle quantum particles, not to mention infinite towers of virtual particles. People have tried to do those calculations and gotten crazy bonkers results, which suggests that what we need is a new theory of quantum gravity that might let us do this and it might work. Right. It might be that the Casimir effect does decrease the local energy density in such a way that a theory of quantum gravity would predict the expansion of space in just the right way to give you a warp bubble. But this paper doesn't show that, right, It doesn't show that. But you know, they're just presenting the results of their simulation and saying there's maybe a link to war drive. Maybe the real problem was that it got picked up by the media and then the headline got over blown because if you read the title of the paper, it's not like, hey, we made a warp drive, it's how would here because you sent to me worldline numerics applied to custom Casimir geometry generates unanticipated intersection with al Kabir warp metric. Yes, absolutely, the title their paper is much better than the title of a Coffee or Die article that says that they accidentally create warp bubble for interstellar travel. I completely agree. And they have the word numerics here, so they are saying that it is a simulation. Now, that's right. A lot of the misunderstanding lies in the coverage of this paper. This paper definitely doesn't show that NASA accidentally created a warp bubble. It just shows that the Casimir effect in certain configurations can generate decreases in local energy density to have a similar shape qualitatively to what you would need for a warp bubble. And again it's just qualitative. They didn't even like analyze quantitatively to say like, is this actually the shape they need? It just sort of like looks the same on the page. Right, So then you might say that NASA might have accidentally built the war drive. Well, also, these guys aren't at NASA. Like nobody here works at NASA. I mean most people who work in NASA to work at NASA, right, They're not like working for NASA. This is not a NASA funded study. This was a study funded by DARPA, however, So that's where the headline made. The mistake should have been the government might have accidentally built a warp drive. Some people in a garage that previously have made outrageous claims did a calculation that looks to them on the screen similar to something they remember being relevant to warp bubbles. Now you're being ours there. I thought anyone could come up with a great idea. Absolutely anybody can, are you say, anybody? If I work at my garage, I can't come up with a good idea. But though these people are at a university, right, some of these folks are. Some of them are in the engineering department at Texas and m which is near NASA. Kind of right, If any two places in Texas are adjacent to each other, then sure, maybe because they have a warp drive ensuring that distance between spots in Texas. Maybe they can't. And absolutely, you're right. Anybody could come up with a great idea and it might be that in somebody's garage one day a warp drive is built. All right, Well, it sounds like the very date here is that the science as it is is not super exaggerated, right, because they are doing simulations and they are just saying there is a qualitative connection there. But sounds like maybe the headline that picked it up did overblow the implications of it or the probability that it might be translated into an actual warp drive. Yeah. I think that's a generous reading of it. Yeah, we already know your harsh reading of it and your friends. Well, let's hope that somebody builds a warp train one day, and you know, we have like a new character on Thomas the train, we have like the warp engine. I think the conclusion here is that maybe these websites that picked it up warp reality a little bit. Yeah, and not accidentally, I imagine. So be careful where you get your science news, but feel free to send us any headline you see that it makes you wonder or it gets you excited, We're happy to digest it for you and give you a sense for whether or not it's the next big breakthrough. That's right, and we need tips on how to use word to make their paper or a tax. You can also email Daniel that's right. Send us your questions about warp drives, about space physics, and about a tech two questions at Daniel and Jorhea dot com. Have you enjoyed that? Thanks for joining us, see you next time. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of I Heart Radio. 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