StarTalk Radio - Cosmic Queries – Theoretical Physics

Episode Date: May 11, 2020

Neil deGrasse Tyson, comic co-host Chuck Nice, and astrophysicist Janna Levin, PhD, answer fan-submitted Cosmic Queries on theoretical physics: black holes, quantum entanglement, energy, dark matter and a lot more! NOTE: StarTalk+ Patrons and All-Access subscribers can watch or listen to this entire episode commercial-free. Thanks to our Patrons Marcus Guerra, Mahmoud Hayat, Tabitha Bradley, John Ward, Cade Carter, Alan Torres, Nícolas Iensen, and James Bales for supporting us this week! Image Credit: ESA/Hubble & NASA, P. Erwin et al. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk. I'm Neil deGrasse Tyson, your personal astrophysicist. And today is a Cosmic Queries edition. Theoretical physics. Chuck, always good to have you. Hey, always good to be here, Neil. I mean, theoretically. This is StarTalk in the Coronaverse. Yeah. You're sitting there in, I guess, in your Jersey home. Is that right? That is correct, sir. I am the Sarah Palin of New Jersey.

I can see New York from my house. And I'm in an undisclosed location somewhere. Some government underground bunker. So theoretical physics, I know probably 10% of what I should to cover this myself. So we got to bring in the big brains for this. That takes us to our close friend of StarTalk, physicist, cosmologist,

Jana Levin. Jana. Hey, man. Welcome back. Good to see you through the ether. Through the ether. Yeah. So get your title straight again. Professor of physics and astronomy at Barnard College. Why, does that mean you get double income for that? Oh yeah, oh yeah. Oh no, that's a good, but I should bring that to the provost, right? Yeah.

No, I mean, we, you know, we're pretty fluid in our subject matter. Okay. We can move around. What it meant was that perhaps the subject should have never been divided in the first place. Well, that's a good point for sure. But that's in fact an interesting point

that even as you well know, Neil, the word scientist is fairly modern. Yeah. Like even the idea of separating science from other forms of thinking about the world or meditating on the world is fairly recent. Yeah, I think that we all used to just be called natural philosophers. Absolutely, yeah. Very cool.

Actually, I'm going to go with scientists is better. Yeah, you like it better? I'm just saying natural philosopher sounds like a BS artist if you talk. Yeah, I mean, I'm just saying. So what do you do for a living? Oh, I'm a natural philosopher. Oh, a BS-er. Oh, no, you're unemployed.

Right. There you go. Unemployed. Well, Check, you got the questions. I do indeed, as usual. Actually, I'm going to lead off with a question. Janet, we did a special Patreon Q&A a few days ago, and I don't know if it's posted yet.

But I answered a question, and when I finished giving the answer, I was disappointed in my answer. Okay. And I just thought maybe you could come give me backup on this. All right. All right? So the question was, as we know, if you fall in towards a black hole, if you observe that phenomenon, it will slow down. And it, in fact,

will appear to stop just outside the event horizon. And so, whereas if you are that, thank you, Chuck. Chuck, yeah. Chuck's moving real slow right now. So if, and so, whereas if you are the person falling, it just happens in real time to you. You don't think about it at all. Yeah. All right.

If we, the observers of things falling into a black hole, see everything freeze at the event horizon, how into a black hole, see everything freeze at the event horizon, how does the black hole ever gain mass as far as our measuring devices would ever reveal? It's actually a little

bit of a subtle question, but for a while, it's so subtle that for a while people used to call them frozen stars because they thought that they just sort of froze and never actually became black holes. But the argument is actually that if I'm falling into a black hole, I have a little bit of mass relative to the mass of the black hole. And so I have my own gravitational field. gravitational field. And as I get epsilon, very, very close to the event horizon, the black hole, I actually deform the event horizon so that it bubbles around me. And I actually fall in, in a finite time, even to somebody far away. Even to somebody far away, they would have to say,

so if I threw in something big, like a star or another black hole, you will see the event horizons absolutely bubble, deform, enveloping each other in a finite time because of the curved space-time of the other object, deforming the event horizon, and it will all happen before your eyes. Wow. So what you're saying is you have your own, not your own event horizon, but you have your own deformation in the fabric of space-time. Yep. And that will deform the event horizon for a second

until it absorbs me. And then, you know, black holes are perfect. They will shed any of those imperfections very, very quickly. But for a second, it will deform, you'll get absorbed, and then it'll usually send out some gravitational waves and ring down. Wow. Okay.

It's like hitting a tennis ball with an invisible racket. I like it. Yeah. So that's why, like, when we heard the two black holes collide, and it happened, and it was over, and one black hole formed, it didn't take an infinite amount of time. And that's because both black holes were. And it happened and it was over. And one black hole formed. It didn't take an infinite amount of time. And that's because both black holes were so big that their own gravitational disturbance of space-time

was so strong that it actually happens to us. We really see it. So they don't freeze into their own event horizons. Right. That's really weird. Yeah. So the objects are both so big and you can actually see in the simulations of

the event horizon that it looks like a big barbell. You know, it really deforms. Dumbbell. Yeah, dumbbell, dumbbell. He's never been to the gym. I'm not much of a weightlifter. I don't know. Yeah. And so it happens don't know. Yeah.

And so it happens fast, actually, even to us from far away. Well, thank you for clarifying that because I did not make that part of this evident in my answer. And Chuck, maybe we can put some indicator back to this posting from the Patreon Q&A that we did just recently. Yeah, yeah. Man, that is really cool stuff, though. All right, let's go to Patreon. Speaking of Patreon, we always start with a Patreon patron because Patreon people support us financially.

Thank you, guys. And this is Cody Klebowski, who says, If time is relative to a person's experience of it, is there a universal base time or is time

only relative? Is there a Greenwich Mean Time for the universe? Yeah, yeah. we're standard time. What have you done with it? Well, actually, when we say things like the universe is 13.8 billion years old, we are referencing a particular cosmic time that on average is about the same for every galaxy. time, that on average is about the same for every galaxy. So if you are not moving relative to the expansion of the universe, the time you will measure is this cosmic time we talk about. So it's not 13.8 billion years just for us on Earth and a completely different age for somebody else

in a different galaxy. As long as the galaxy is relatively slow moving compared to the expansion of the universe, it's just kind of going along with things for the ride, then this is your equivalent kind of mean time. It's a cosmic time that we can all agree on. Wow. What you're saying is because galaxies have motion among other galaxies. Yeah. So that has nothing to do with the expanding universe. Yeah. So this motion, you can, if they go really fast or slow,

there'd be a time shift, a relative time shift. But that's a detail relative to the... It's a tiny, small, small correction, basically. And if you were traveling relative to the expansion of the universe, you're the speed of light for the entire history of the universe, you would certainly disagree about the age of the universe. You would not be saying it's roughly 14 billion years old. But no galaxy is doing that. No galaxy is doing that. And in fact, even if they were going fast at once,

there's a lot of that cosmic expansion slows them down. They tend to slow, you know, so all the galaxies tend to kind of get very slow moving relative to the expansion of the universe. So what about the fact that as I see farther away, the speed of the galaxy receding from me is getting greater and greater? Yeah, it's a great question. So there's some distance at which it might be receding at the speed of light. Yeah. For me, I should see no time pass for that object. Is that not correct? No. So actually what's happening is the object itself is not moving in some sense relative to the expansion of the universe at all, it's the space that's stretching between us. And so the space is stretching between us faster than the speed of light. But in most circumstances, a light beam can just still make its way over to us eventually, if you wait long enough.

And so if the universe is slowing down, every galaxy will eventually be visible to us as we wait long enough. But if the universe is actually accelerating, which is what it seems to be doing right now, there will be a distance beyond which the light will not be able to outrace the expansion of the universe. And we will never see those galaxies.

And it will be like having an event horizon like you do for a black hole. It will be a cosmic event horizon where we are never to see or know or be able to communicate with what goes on beyond that distance. Because it is receding faster than the light can overcome the stretching of the space. That's right. So the light is racing and racing and racing, but the space is stretching faster and it's never going to overcome. Okay. So the one where it is just exactly at the expansion rate for the light to exactly compensate for the stretching of the universe, if we see that light, that's going to be frozen, isn't it? Oh, so yes. In the same way that there's, so if it's accelerating and there's and that happens and there is something, it's an horizon indeed there is a last signal we will get so if something is

just on this side of that event horizon we'll see it in the infinite future and if something's just on the other side the light will just seem to hover there will never seem to get to us okay but it will but will will we see it reckon time differently from how we reckon time? Well, it depends on what you mean by it there. The galaxy itself could be measuring the same cosmic time. That's what I was wondering. But light, you know, almost registers no passage of time. Yeah, no passage of time, right.

But the galaxy itself, as long as it was just being dragged along with the expansion, should agree with us that the universe is about 14 billion years old. That's the answer. So there you go. That's it. There it is. Good light don't crack. That's all there is. You are such a nut, Chuck.

Oh, did you notice I'm wearing my, I meant to show you this earlier. It's my space shuttle Bolo. Oh, very nice. I always have to wear something themed for you, Neil. Thank you. Thank you.

I feel bad because I got, I don't, I feel bad. It's quarantine. There's only so much we can do. Chuck, you got another question? All right. Let's go back to Patreon. And let's go to Peter Jacobs. Peter Jacobs says...

You didn't pick him just because you can pronounce his name. Yes, I did. You know, because the other person's name was Flavie Flop. All right. Peter Jacobs wants to know this. It was Flavie Flav. All right. Peter Jacobs wants to know this.

Peter Jacobs says, is energy a thing or is it just a relationship between things? And he's coming to us from Queensland, Australia. Good day, mate. Good day, mate. Good day. And actually, we have to take a break right now. And we'll come back to that because that's an excellent question. I think it has a deeper, broader significance.

Does the measurement of anything, does it only have meaning with regard to something else? Can it have absolute meaning without regard to whoever is looking at it or measuring it? So when we come back, we will pick up Cosmic Queries Theoretical Physics Edition with our friend and my colleague, Jenna Levin. we're back cosmic queries theoretical physics division but i need help and we got help We didn't have to reach too far. Jan 11. Jan, always good to have you. Always good to be here. Here. Got the question. Here, yeah.

Here. Here. Exactly. We're all here. And, yeah. So, Peter Jacobs, before the break, asked, is energy a thing, or is it just a relationship between things i love that where does that come from where's that going i don't know i thought i thought you

were gonna have a a prompt but i'll do a quick one and then i'd love to hear your opinion but okay to some you know i think it's both. So for instance, if I'm sitting still in space, but I'm moving in time, I still have some energy. That's what Einstein taught us. I have a kinetic energy in time in some sense because of my motion in time. And that's my E equals MC squared energy. And that's my basic,

you can actually unambiguously break my atoms apart and get that energy out and blow things up and have real impact. Without reference to anything else. Without reference to anything else. But if we're astronauts floating in space and I think I'm just moving in time with my kinetic energy equals mc squared

in time but you go whizzing past me you think I'm moving past you and so now you think I have a relative kinetic energy that I don't think I have that's of my motion in space so it's kind of both wow both okay so in other words okay the way it wouldn't be both is if the question were asked whether mass energy was something relative to something else because i can measure you to have a different amount of kinetic energy in time versus right man i can say i have no kinetic energy in space and you can say i have a lot of kinetic energy in space because you just saw me fly by. And we're both, because I was flying by you, but how would I know?

Right. So, but if I add up your time energy and your spatial energy, that should be a constant no matter what. So that's an interesting question. What's actually constant is a combination of my energy and my spatial momentum my kinetic energy yes that come a combination of the squares weirdly

of my energy and my in time and my kinetic energy um that that will be the same even though we'll disagree about what's what we have a way to calculate what would be the same, even though we'll disagree about what's what. We have a way to calculate what would be the same for every observer onto you. That's right. And so it's interesting. So let's say you tell me that you're looking three feet to your left.

I might disagree that it's to your left. I might say it's to my left or I'm sorry, my right, but we're going to agree on the overall combination. And so it's similar with like time energy and physical spatial kinetic energy. We're going to disagree on which piece, if it's how it's distributed, but we're going to agree on a combination.

Excellent. That is really good. By the way, I forgot all about that formula. We have the squares of the energies. I remember that now. I just like- Yeah, E squared minus P squared. Yeah, exactly.

From my relative- E squared minus P squared. Yeah. All right. So. I felt left out a little bit on that. I'm like, hmm. I feel like we can keep going, but we'd regret the rabbit hole we'd fall down.

And that is a rabbit hole, man, for real. But that's a very cool question. Thank you, Peter. Let's go to Facebook and Steve Cotton. Steve says, will quantum entanglement allow for FTL or instant communication to exist between worlds with light years of distance between them. This is clearly a Star Trek fan who knows about subspace, which is how they get around talking to people in almost real time, even though they're in different galaxies.

They have this thing called subspace. And what's it mean? Nothing. It means... Wait, wait, wait. Chuck, just to be clear, you're laughing at it, but at least they thought about that problem

and came up with a sci-fi solution to it. Okay, all right. Okay, I'm going to give you that. Don't make me continue slapping you. Listen, you know what? I got to give it to you. That is actually, that is a seriously salient consideration. I got to give it

to you. You're right. All right. So anyway, go ahead. So Jana, let me read. I missed the question. Quantum entanglement allow for FTL or instant communication to exist between worlds with light years

or distances between them. So Jana, let me just ask you something. I want to prep this and ask you, do you even need quantum entanglement if you have wormholes? No, you don't need quantum entanglement if you have wormholes. And in a wormhole, you can actually put material things through the wormhole. And I just open a portal and it's right there in the back door. Yeah.

And Neil, as I know you've made the point before, it's not that it's faster than light travel. You've just found a shortcut. It's like somebody going between New York and New Jersey by going all the way around the globe, right? And thinking it's really far away. And you tell them, actually, you can just go this way. The shorter way. The Lincoln Tunnel.

So the wormhole gives you a shorter way. The wormhole is the Lincoln Tunnel. Okay. Yeah. So the wormhole makes a veritable shortcut where you travel slower than the speed of light. And you just have a shorter distance to go. Right. And you're slower than the speed of light while you're in the wormhole.

Totally. Yeah. The distance, right. Yeah. And the other thing that I know we've talked about before is this warp drive idea, which is that space can expand faster than the speed of light and contract faster than the speed of light without violating special relativity or any of those laws.

So you can also bring something closer, take a short step across the pond, and then push it further away again by just expanding the space. This would be awesome control over the space-time continuum to accomplish this. Yeah. Awesome control. Okay. So what's more likely to happen? That we perfect quantum entanglement faster than light communication?

Or that we open up wormholes throughout the galaxy? Quantum entanglement is actually happening. Like we do it in the lab. I mean, we don't do it in the scale that the question was asked from one galaxy to another because we also can't get our own selves to another galaxy. But we can definitely do this experiment where we throw things faster than,

we throw information faster than the speed of light um that's amazing i mean but i mean it is amazing i mean i even think it's amazing like i know the theory and then you find out somebody's done it in the lab and you're like i mean because the implications there are kind of like if you look at all of our telecommunications today, it started with one quick, one sentence, you know, Watson, come here. So think about, and the dude was literally in the next room. And they thought that was like, oh my God, that's amazing. He just called me in the, I mean, he could have actually went like this Watson and Watson okay and it would have been more effective so honestly that's what you're saying is just mind-blowing but Chuck don't you think we're

so unappreciative of how amazing this is right now like I don't even know where to look I got so many squares to look at on my screen I don't even know where to look. I got so many squares to look at on my screen. I don't even know. Like, I'm looking all over the place, but we're taking so for granted that this, we're doing this, this is amazing. This is phenomenal. We're just used to it. Wow.

Yeah. So now a quick question, Janet, is what's the difference, functional difference, between a collapsed wave function in the quantum entanglement and that information is shared instantly, not just faster than the speed of light, instantly. Yeah.

What's in between that and... Oh, but see, here's... Oh, sorry, I don't mean to interrupt you. But instantly according to whom? So there are some very tricky things about... Because simultaneity is relative. All right. Okay.

That's it. Show's over. Show's over. I got to go. I'm sorry. I can't. Dropping my headphones doesn't seem like quite as dramatic. Wow.

And I am not dropping this microphone. Do not drop them. Okay. Okay. Sorry, Neil. Okay. Go ahead. What you were saying. Yeah. So it's instantaneous according to the person who does the observation. Tunneling. A particle is over here and there's a barrier of any kind and there's a chance it'll just show up on the other side of that barrier. Yeah. But when it does so, that happens instantly. Yeah. It does so instantly, but you can kind of calculate the natural timescale for it to happen. Gotcha. Okay.

But it doesn't mean it doesn't happen instantly. But it does mean like, oh, do I have to wait for a Googleplex of years for this to happen? Or is it likely to happen in a year or in a second? And you can do experiments where it's more likely to happen in a short period of time. So if you do a whole bunch of them, if you put a whole bunch of particles in a box in your laboratory, you'll see a whole bunch tunnel through on the other side at about a second. And so you're right, it's still instantaneous, but it's just what's the likelihood of it happening in a certain period of time. Now, I got to throw this in here, just I'm being Professor Neil in this moment, but we knew for the longest time that if there were ever

going to undergo nuclear fusion anywhere in the universe, that the centers of stars would be the place that that would have to happen. Yeah. So what people did was calculate the temperature in the centers of stars. And we were getting millions of degrees. Okay?

Just do the thermodynamics of that. Yeah. You run the quantum calculation, sorry, you run the calculation of, is that a high enough temperature for protons to overcome their natural repulsion? You have two positive charges. They don't want to get close to each other. But to fuse them, you've got to bring them together to turn them into another element. So can you overcome it?

They did the math, and they could not overcome the repulsion. So they said the centers of stars can't be the place where this happens because we did the math and they could not overcome the repulsion. So they said the centers of stars can't be the place where this happens because we did the math and we know thermodynamics. And then quantum physics gets discovered. And then we learn about tunneling. And then we learned that at the temperatures in the centers of the stars, the proton can disappear from here and show up right next to the other proton bypassing the electrical barrier. And when it bypasses the barrier, it fuses. You turn hydrogen into helium.

And it was the tunneling that even enabled anybody to accept that stars could be the source of helium. I just had to throw it. That is amazing. Yes. The temperature is not high enough. I can't believe believe why have you never told me this story before well it's not really a story but still by the way that is just so the the original calculations led them to believe that this is not the place that it could actually happen. But, but in all fairness,

Arthur Eddington, I think it was him. It was one of the great towering theoretical physicists at the turn of the century, a hundred years ago, someone came up to him and said, do you see it's impossible. You can't overcome this electrical repulsion. And he said,

I don't care. If there's any place in the universe where this is going to happen at all, it's going to be in the center of the star. We're going to find out one day. Yeah, I mean, you can kind of, you know when you get in a zone and your numbers are off by not enough

for you to abandon the idea. They're off by enough for you to know you haven't understood everything, but not enough for you to abandon the idea. Right, so you stick with it. Wow, that is super. Chuck, it wasn't to no basis. That's super fascinating, though. I mean, that's, God, that's so cool.

All right, here we go. Fred P. Vanessa. Whatever. Fred P. Vanessa. Whatever. Fred. Never apply to work at the United Nations. I know. I will start many global incidents. Like, what you calling me?

Anyway. Chuck was doing a translation. You got to let him him cut him some slack uh he says um what is space made of wow because you know we hear about the fabric of space what is that fabric oh okay chuck we don't have time to answer that until the next break okay you like that so love that question and i know janna loves it too look at that smile there's a lot that's going to come out of this one totally uh we're going to take a quick break No. Love that question. And I know Jana loves it too. Look at that smile. There's a lot that's going to come out of this one. We're going to take a quick break from Star Talk Cosmic Queries, Theoretical Physics Edition.

We'll be right back. Hey, we'd like to give a Patreon shout out to the following Patreon patrons, Marcus Guerra and Mahmoud Hyatt. Guys, thanks so much for the gravity assist. Without you, we could not do this. And for anyone else who would like their very own Patreon shout out, please go to Patreon.com slash StarTalk Radio and support us. We're back for the third and final segment of Stark Talk Cosmic Queries Theoretical Physics Edition. I love it. We should do this more often Chuck. Man, it's really good, really good. Of course I need help for that. Jan 11, Jana. So Chuck, we left off. So Fred Pivonessa, right? Nope. Yeah.

Nope. Yep. Nope. It's... Pio Vizzana. Pio Vizzana. That's what it is. Okay. Pio Vizzana. Okay.

Sorry, Fred. Wait, wait. Pio Vizzana, but his first name is Fred? It's probably Federico or Frederico. And it just went with Fred. He's making it easier for Chuck. Right on. Anyway, Fred wants to know this.

What is space made of? So everybody talks about the fabric of space. What's that fabric? Let me lead into you here, Janice. So we like to think of, just naively, that naively that okay there's earth and then there's air and then where there's no air there's empty space so we so we have a word for what we think contains nothing so i can't holding aside stray atmospheric particles that might be floating up there that's not what we were talking about here. No. Emptiness. Between the particles. So give me the most empty space you can. Yeah. Talk

about it. Wow. Well, I'm going to give an answer that I don't 100% understand or believe. Okay. understand or believe. Okay. But let's say all the time. So right now he neither understands nor believes all the time. That's it. That's where I'm a Viking. I think that this is, I would say this, I think this is how we can understand it now. Okay. And that our understanding will change. Good. So right now, I know that my room is full of electric and magnetic fields. And I cannot see them, but they make a fabric of the electromagnetic fields in the universe. They're just there. I know they're there because I'm looking at you right now on an electronic instrument, and this is just a reality that the fields are here.

Even though I can't, my eyes aren't good detectors of them, my fingers aren't good detectors of them, and I don't notice them. Wait, just to be clear, the fact that light can move through empty space, from wherever it started to its destination, your retina, from wherever it started to its destination, your retina, being space is permeated by electromagnetic energy. Yeah, and we can see that version of electromagnetic energy, the one that oscillates at just the right frequency that my eyes evolve to be able to detect, but I can't see the ones that my phone's detecting.

Like when my phone goes off, I don't see like flashes. Versus microwave light. Yeah, or even not light at all, like steady electric fields. But yes, most of them are usually light signals. But right now there's probably just a steady electric field in this room that permeates a whole space. It's just from God knows what. And I can't see it, feel it, touch it because it doesn't resonate with my particles very well. So I can say that there are fields

that permeate the universe and they make a fabric of that field, of the electromagnetic field. I would say in analogy, there is a gravitational field. And the gravitational field is analogous to a curved spacetime. It describes the curved spacetime.

The gravitational field defines the shape of spacetime. And my eyes are not good detectors of it, and my hands don't touch it, but I fall along it. If I were to jump off my chair, I would fall along this gravitational field. And so that is the fabric of space in some sense. All right, but Jana, I think that's a cop-out answer because...

Pistey cuffs. Oh, sure, you're far away. Say that to me in person. No, I totally followed the answer, but let me take you a step forward. I want to push you. Yep. You were describing what happens to be in the empty space of the universe in which we live.

Can you imagine empty space through which there is no electromagnetic field and where there is no curvature from matter. I cannot imagine space as separated from a gravitational field, including a flat, empty gravitational field. But when we learn general relativity, one of the ways you start there is imagine a flat space with no matter. Yep. I would still call that a gravitational field. I would just call it a flat, straight, very boring gravitational field.

A gravitational field with no sources of gravity in it. Yeah. I feel like you. So let me put it this way. It doesn't mean it doesn't have space in it. So let me put it this way. You're trying to give the existence of space. You're trying to credit the existence of space.

I would say that's... Something that happens to be in it. No, no, I would say it this way. I would say there are gravitational fields even with zero sources. So I would say it this way. I would say there are gravitational fields, even with zero sources. So I would put it that way. So I would say I take Einstein's equations, which as you said, says put in a source, a sun, a black hole, a moon, whatever. And you will find the curvature in the shape of space-time, also known as a gravitational field. field. I can take Einstein's equations and put in zero sources and find as a solution a gravitational field that is just extremely plain where things travel on straight lines. Okay. Wow. So in other words, it's the ground state or the lowest energy state of the field and that there is no state of the field where space doesn't exist. It just is the ground state. It is the ground state. I know. Wait, so what about a universe

that pops out in the multiverse that has no matter and no energy in it? Well, are you asking what it would be? Yeah. Well, this is, you know, it would be in principle, if there are no observers, it becomes one of those questions of there's no one to measure time. There's no passage of time. There's no experience of space. It's got to have something in it to even ask the questions. Okay. So, all right. But a universe that pops out of existence with nothing in it could just be a plain old flat space with nothing in it. I mean, I don't know, but you're really, you're talking about something where there's no meaning to the passage of time.

Okay. So how about, now let's get quantum on this. Yeah. I've read about, and I just, as you said earlier, I accept it because people I trust have thought about this and are far better experts at quantum physics than I am. They describe space as a seething soup of virtual particles popping in and out of existence. Yeah. Virtual matter-antimatter particle pairs.

Yeah. But what is a virtual particle? So this goes back to the Heisenberg uncertainty principle, which really initiates the whole quantum revolution. And the uncertainty principle... Heisenberg, not from Breaking Bad, just to be clear. Oh, no, but do you think they were fans of physics? But Heisenberg, German physicist who realized that there is a level of uncertainty to how much we can

know, but the real impact of what Heisenberg said is he said, in some sense, I can never know a particle is precisely there, so I can never know a particle's not there. So if I have empty space, the uncertainty principle ensures that I cannot declare it to have nothing in it, because I can never say with certainty a particle isn't there. In the same way that I can't say for certainty a particle is there. And so virtual particles are in some sense a manifestation of this fundamental uncertainty. You cannot have an absolute vacuum empty state. It cannot be. Uncertainty doesn't allow it. It says that there is always some possibility. How do you measure it? Oh, you know what? We've never measured a vacuum fluctuation. And this is a really interesting,

really interesting point, which is something I didn't appreciate until fairly recently. But we do see effects, like there's something called the Casimir effect. So the Casimir effect, where we put two metal plates together, and it's a way of limiting the number of vacuum states that can exist because of these boundaries. It's sort of like excluding all, not every possibility is allowed, and it creates a difference in the vacuum fluctuations on one side of the plates than on the other side of the plates, and that creates a pressure differential, and you can actually measure it. So I've forgotten about that Casimir effect. So as I understand it, you need very flat plates, very parallel,

and they have to be separated from each other on the level of the wavelength of the virtual particles themselves. Right. It's a very subtle, small detail, very fascinating experiment. And when you do that, they want to actually pull together with a force, a new force that just shows up because of this. And it's like saying the quantum pressure of the fluctuations on one side exceeds the quantum pressure of the fluctuations on the other side, because you've made it impossible for some states to exist between these boundaries, basically. And but but it's not exactly a direct measurement. You don't measure a virtual particle. And so in some subtle sense, it's a beautiful indirect measurement. But we can't be like, oh, I just saw a particle pop into existence and disappear again.

So basically what you're saying for Fred is that there can never be nothing. There can never be nothing. There can never be nothing. That's basically what it comes down to. Yeah. So not even nothing has nothing. Nothing, right.

Nothing is something. Which is one of the arguments. By the way, I keep trying to tell my wife that. It's one of the arguments for dark energy, is that what dark energy is. And it's connected to the two questions. That what dark energy is. But that mysterious pressure in the vacuum of space. It's the mysterious pressure in the vacuum of space from quantum behaviors.

And it's because even in an empty, flat space, the universe that you asked about, Neil, there is a gravitational field. And the gravitational field has an energy associated with it. And it's the energy associated with the quantum fluctuations. Wow. Okay. God. Damn. I. Okay. God. Damn. I'm exhausted.

We got to do more theoretical physics. I love this. I love theoretical physics. It's amazing. This is crazy stuff. Yeah. This is crazy. I got to tell you the truth.

I am so sorry that I spent so much of my young life doing drugs. I could have been doing this. This is just as good. I could have been easily. I was hanging out with the wrong. Here I am hanging out with the stupid people who want to smoke weed and drink. I should have been hanging out with the doggone physicist. I know, man.

I'm telling you. That's how we roll. Yeah. Always great to have you on. Always fun to be on, guys. We need more installments of theoretical physics. Yeah. Happy to. Anytime. And everyone hang in there. It's good to see you all. Thank you. In the coroniverse, Chuck.

In the coroniverse. Stay safe. A pleasure. Stay safe, guys. All right. Good. I'm Neil A pleasure. Stay safe, guys. All right. Good. I'm Neil deGrasse Tyson, your personal astrophysicist, signing off from Cosmic Queries Theoretical Physics Edition. As always, keep looking up.