Daniel and Jorge Explain the UniverseDaniel and Jorge tackle the confusing conundrum of the Casimir Effect and quantum zero-point energy
Learn more about your ad-choices at https://www.iheartpodcastnetwork.com
See omnystudio.com/listener for privacy information.
If you love iPhone, you'll love Apple Card. It's the credit card designed for iPhone. It gives you unlimited daily cash back that can earn four point four zero percent annual percentage yield. When you open a high Yield savings account through Apple Card, apply for Applecard in the wallet app subject to credit approval. Savings is available to Apple Card owners subject to eligibility. Apple Card and Savings by Goldman Sachs Bank USA, Salt Lake City Branch Member FDIC terms and more at applecard dot com. When you pop a piece of cheese into your mouth, you're probably not thinking about the environmental impact. But the people in the dairy industry are. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. How is US Dairy tackling greenhouse gases? Many farms use anaerobic digesters to turn the methane from manure into renewable energy that can power farms, towns, and electric cars. Visit us Dairy dot COM's Last Sustainability to learn more.
Here's a little secret. Most smartphone deals aren't that exciting. To be honest, they're barely worth mentioning. But then there's AT and T and their best deals. Those are quite exciting.
They're the kind of deals that are really worth talking about, like their deal in the new Samsung Galaxy Z flip six. With this deal, you can trade in your eligible smartphone, any year, any condition for a new Samsung Galaxy Z flip six.
It's so good, in fact, it will have.
You shouting from the rooftops. So get yourself down a street level and learn how to snag the new Samsung Galaxy Z flip six on AT and T and maybe grab a ladder on the way home. AT and T connecting changes everything requires trade in a Galaxy s Note or Z series smartphone, Limited time offer two hundred and fifty six gigabytes for zero dollars. Additional fees, terms and restrictions apply. See att dot com, slash Samsung, or visit an AT and T store for details.
You know, Jorge, Sometimes I wish that particle physics was more useful.
More useful than creating black holes and particle colliders to threaten the Earth.
Yeah, sometimes I wish that we could unlock the power of physics to do something good for humanity.
He could work on like renewal energies and stuff like that.
Actually, I do have some crazy ideas about that.
Oh yeah, how crazy are we talking about?
Very crazy? Maybe infinitely crazy?
Well, I'm infinitely interested in infinite energy.
Fortunately we only have a finite time on today's podcast.
I am Horehemming cartoonists and the creator of PhD Hi.
I'm Daniel. I'm a particle of physicists, and I'm technically made of an infinite number of particles.
What do you mean there's an infinite amount of you? How much did you have over Thanksgiving dinner?
Is that too much Daniel for you to take?
That's an infinity too much for anyone.
No, in this sense that we're all made out of a potentially infinite number of fluctuating particles pomping in and out of the vacuum. M we're mathematically infinite.
The vacuum of space always full of surprises. I feel like, yeah, you never know what it's going to pop out or give you or hand you for Christmas.
It's infinitely surprising.
So welcome to our podcast. Daniel and Jorge Explain the Universe, a production of iHeartRadio.
In which we examine the infinite with a cold eye. We don't look away. We try to understand it. We think about the infinity of space, We think about the infinities in space. We think about everything there is out there in the universe, and we talk about it in a way that we hope makes sense to you.
That's right. We stare down the universe until it tells us what infinite secrets it has hiding inside of its very own fabric.
That's right, because there is an infinite amount of joy in revealing the truth of the universe. Science is an amazing project. We just find ourselves as conscious beings in this universe trying slowly to chip away at the truth and figure out how does it all work, What does it all mean? Does it make sense? Is it possible for humans to make sense of it?
Yeah, because it is a big universe, and it is full of strange phenomena phenomenon that feels really strange to our everyday experience, like, for example, the idea of infinite things. We're not used to infinite things on Earth. We're used to finite things, things with a limit. At least that's what our parents tell us.
That's right. I still have not yet eaten an infinite number of cookies though it's an ongoing project.
That's right. You can't say you haven't or you won't.
That's right, give me enough time, But you're right. Infinity is a hard thing to grapple with. It's both like impossible to hold in your head and also like every day it's weird to think about the universe being infinite in extent, but it's not weird to realize that there are an infinite number of numbers between zero and one, for example. So it's a pretty weird thing.
Yeah, And not only could the universe be infinite, it could have infinities inside of it.
There might be an infinity of infinities, right. It might be that everywhere around us there are infinite particles popping in and out of the vacuum. And when you dig down deeper into what that means about space, it might tell you something very strange.
So today on the podcast, we'll be asking the question, is space filled with infinite energy?
And can I use that to charge my iPhone?
That would be pretty useful, Like a phone that just charges if you just hold it up in the air, that would be useful. Daniel, stop writing papers about the fabric of reality and Jesse get us that air charger.
All right, I'm gonna move from papers to patents. That's my plan for the week.
Yeah, I mean, I know Apple has like the iPod air or iMac air. It just makes like the air.
The vacuum you go. But I think this touches on something which is really at the heart of what we're doing with the whole physics project, which is trying to make sense of the universe and then wondering is our understanding real Like we talk about space being filled with vacuum, which is filled with these quantum frothing particles, but are they really there or is that just something in our minds? Could we do experiments to figure out if they really are there or if these are just calculations we're doing in our head.
Yeah. So the idea is that there's a there's a concept right in physics that the universe is not empty, it's filled with fields like quantum fields, and these fields are not just sitting there or they're not empty of energy.
Yeah, exactly. Because these fields are quantum, they have a special property that they can never actually have zero energy in them. And so according to nantum physics, all of space should be filled with an infinite number of particles, which should correspond to a real energy, which technically means an infinite amount of energy in every piece of space.
Yeah, and like they can't just chill, Like they can't just bottom out. They always have to have like a little bit of like a buzz to them, right.
Yeah, that's kind of the idea, and that's sort of hard to grapple with. But it turns out there's a really interesting experiment that studies something called the Casimir effect, which might be sensitive to whether these particles really are out there, And this experiment tells us something amazing.
Yeah, the Casimir effect is a really interesting well just the name, and I have to say, at first, I thought it was sort of a reference to the rains of Casimir, and I thought, Oh, that's not going to end well for this podcast.
Are we gonna end up at the Red Wedding at the end of.
This I hope not. I'm gonna be good from Game of Thrones.
But not everything, it turns out is a Game of Thrones reference. This is actually a physics effect predicted a long time ago and recently observed.
Yeah, it's an idea that's been around for a long time, like over fifty years, seventy years, the Casimir effect.
Yeah, and these are beautiful ideas, the idea to test a crazy theory of physics by coming up with an experiment that could actually pin it down, that could corner nature and force it to reveal to us what's really going on out there in space.
Yeah. So this effect is a little obscure, I think, but it might sort of reveal that the universe is or is not filled with infinite energy. So, as usually, we were wondering how many people had even heard of this experiment or effect, and so Daniel went out there into the wilds of the internet to ask people what is the Casimir effect?
So thanks to everybody who participated with so much evident joy and enthusiasm. If you would like to speculate basically and without reference materials on future questions for the podcast, please write to us to questions at Daniel and Jorge dot com.
So before you listen to these answers, think about it for a second. If someone asks you what is the Casimir effect not the reigns of Casimir? What would you say? Here's what people had to say. It makes me think of something to do with suns, So maybe sun flares or something of the sort.
I have no idea what that could be.
I'm going to guess that Kasimir was a scientist and he was either casually or actively observing something and noticed an effect that perhaps had not been noticed before.
To see the Casimir effect, you put two metallic plates close together. Then they move even closer together because the number of particle antiparticle or virtual particle antiparticle pairs outside the place is greater than those between the plates. So the particles outside exert a non zero net force on the plates and they moved closer together.
Was named after a guy named Kasimir.
Well, do you think that means we have no Game of Thrones fans because nobody else thought this was the reigns of Casimir.
Maybe our fantasy fan and physics loving audience doesn't overlap.
But there were some pretty good guesses here. I like the it was named after a guy named Casimir.
Hmmm, interesting, that would be normally a good guess in physics.
Yeah, exactly.
But also a lot of people just didn't know what it is or had heard of it before. It doesn't seem to have good PR.
Yeah, exactly. I think Casimir and his PR team definitely need some like social media tips.
Well step us through this. Daniel, First of all, Yeah, what is this idea that space is filled with energy?
It's a really sort of Bonker's idea, but it's also totally realistic, which is my favorite thing about physics. And to get into this, you have to really understand how quantum physics looks at space, like what is space? And if you're the kind of person that thinks, well, space is nothing, right, spaces emptiness, space is the gap between stuff, then remember that modern physics has a different view of space. There's this sort of general relativity view of space that tells us how space can bend and twist and ripple. That's awesome, but we're going to put that aside today and we're going to look at the quantum physics view of space. The quantum physics view of space says that space is not emptiness. Space is like a parking lot. It has all these fields in it which can be filled with particles or they can be empty. So you can imagine, for example, all of the universe being filled with an electron field, and where there are electrons that just means that field has a little bit of energy in it. It's vibrating, and that corresponds to an electron. And where there aren't electrons, than those fields are empty, they're not vibrating as much.
Yeah, this idea of space is maybe a little bit closer to what most people think of space before they learn about relativity. It is sort of like a big empty warehouse, like a big empty space, but it's filled with something, right.
Yeah, exactly. And I think the mental shift you need to make to understand it from the field point of view is that you don't have, for example, an electron moving through empty space as a particle, just like floating through nothing. Instead, you can think of that electron moving through space is like a wiggle on a string. That wiggle moves along the string, but it's really the string that's doing the wiggling. So in this case, an electron moving through space is a vibration in the electron field, and that vibration is passing through the field.
I always kind of think about it as like having a giant room and then like having a giant blanket over it. That would be the quantum field, and electron is like a little bump in the blanket that you know kind of moves around.
That sounds pretty cozy. Your theory of the universe doesn't sound like cold and empty. It sounds like snugging in a cold, rainy day. It's called the cozy effect, exact, the quantum cozy effect, Yeah, exactly. And so you can imagine that blanket, you know, gets pushed up when you have a particle under it. And the cool thing about this way to think about it is that it's very easy to then have two particles, because then your quantum field in that spot is now excited a little bit more, and three particles is just another excitation in the field. So this actually technically is very powerful because it allows you to think about the creation and destruction of individual quantum particles. Whereas the earlier the old school quantum mechanics followed the path of an individual particle, and so it was very difficult to calculate like what happened when it was destroyed, or how do you follow two or three particles. So the quantum field approach is the more modern approach, partially because it's just technically easier to like actually calculate things.
Yeah, and there's not just one field. There's like a bunch of fields in the universe, right, Like it's not just one blanket covering my warehouse. It's like a whole bunch of blankets tacked together.
Yeah, every place in space has a field for every possible particle. So every point in space has an electron field, a muon field, a quark field, you know, electromagnetic fields for the photons. All of these different fields in the same place. And sometimes these fields don't interact with each other at all. Right, some of these articles don't interact with each other, and so these fields don't interact with each other, but sometimes they do. For example, the electron and the photon do interact with each other, right, Electrons give off photons, so those fields are coupled together. So it's a bunch of different fields, but some of them interact with each other. They're tied together by these forces.
Some blankets are just sewn a little bit with other blankets.
Yeah, exactly, if you make a wiggle in one, it'll spread that energy out into others, and some of them slosh back and forth. It's pretty cool. And you know, one of the projects of particle physics is to take this big stack of nineteen blankets we have and understand them all as like part of one big blanket that's just sort of like wiggling together according to one set of rules. We're trying to unify the whole system of these different fields and understand them in the context of like one field that unifies them all. But that's the subject for a whole different podcast for today. The thing we need to think about is what it means when these fields are emptiest.
Yeah. Now, I guess the question is do quantum physicists think of space is separate from these fields? Do you know what I mean? Like, is space the empty warehouse and then you put fields in it? Or do you think of it that you can't have space without quantum fields.
You can't have space without quantum fields. Yeah, exactly. These fields fill the whole universe. There's no place in space where you don't have these fields. And you could ask, like, does that mean that that's what space is? I'm not sure. I mean, quantum mechanics usually consider space to be sort of like firm and absolute. It prefers to deal with sort of flat space rather than like the curved space or weirdly connected space of general relativity. It is possible in some context to connect the two, but we've never achieved like a full connection. To understand quantum mechanics and curved space altogether in all sorts of contexts, that would be quantum gravity. So quantum mechanics view space as sort of like flat and absolute, and then you have the fields in space. But you can't have any part of space without those fields.
Right, right, But you can't have places where the field is not excited as usual, right, that's what you call it, like empty or vacuum.
Yeah, you can have a vacuum, and vacuum sort of calls to mind the idea of emptiness of nothingness, right, or maybe lowest energy state. And in classical physics, like before quantum mechanics, that meant zero. Like if you had an electromagnetic field classically, like one hundred and fifty years ago, back when Maxwell was doing this stuff, you could turn it on and you could turn it off, and when it was off it was at zero. But quantum fields can't actually do that. Quantum fields can't settle down to zero energy. Wow, that's weird.
What does that mean? Like even though nothing is there or exciting it, or you know happening there, it still has some kind of potential or some kind of like motion. What does that mean that it doesn't have zero energy?
That's really the heart of the question. What does it mean? And you said, for example, nothing is there, we don't really know if nothing is there, what it means is that quantum fields in their lowest possible state are in a state with non zero energy. This is called the zero point energy. And if you solve the math for how quantum systems work, they always have a minimum non zero energy. It's just not possible to get the quantum field down to zero energy, and so we don't know what that means. That's the heart of the question. Does it mean that there are like little virtual particles actually there with real energy? Is it a weird mathematical artifact that we're just not understanding. Is it a clue into something else? Like? What does this actually mean? Is the heart of the question.
I guess what do you mean it can't have zero energy? Like it's not likely or it's just like theoretically impossible, it would break some kind of math equation. What does it mean? Like, how do you know it can't have zero energy? Like couldn't it fluctuate and sometimes dip below zero.
So that's a great question. Remember the quantum mechanics gives us probability, so it allows fluctuations, but it allows fluctuations between physically possible solutions. Like you might solve an equation that says, here's nine different things an electron can do. I don't know exactly what when it's going to do, and I can tell you the probabilities of various ones, and it might fluctuate between them, but it has to do one of these things. Doesn't mean the rules are off and anything can happen. And when you solve the quantum mechanics of a system and empty space, these fields in empty space, you get a bunch of solutions, and those solutions are quantized, and the solutions are like one particle, two particles, three particles, four particles. But the zero particle solution doesn't have zero energy. It has a minimum amount of energy. When you solve the mathematics, you get a state with no particles but with energy.
Right, So, and somehow this kind of leads to the idea that space has infinite energy. So let's get into connecting those dots and let's talk about this interesting Casimir effect. But first, let's take a quick break.
With big wireless providers, what you see is never what you get. Somewhere between the store and your first month's bill, the price you thought you were paying magically skyrockets. With mint Mobile, you'll never have to worry about gotcha's ever again. When Mint Mobile says fifteen dollars a month for a three month plan, they really mean it. I've used mint Mobile and the call quality is always so crisp and so clear. I can recommend it to you, So say bye bye to your overpriced wireless plans, jaw dropping monthly bills and unexpected overages. You can use your own phone with any mint Mobile plan and bring your phone number along with your existing contacts. So dit your overpriced wireless with mint Mobiles deal and get three months a premium wireless service for fifteen bucks a month. To get this new customer offer and your new three month premium wireless plan for just fifteen bucks a month, go to mintmobile dot com slash universe. That's mintmobile dot com slash universe. Cut your wireless bill to fifteen bucks a month at mintmobile dot com slash universe. Forty five dollars upfront payment required equivalent to fifteen dollars per month new customers on first three month plan only speeds slower about forty gigabytes on unlimited plan. Additional taxi spees and restrictions apply. See mint mobile for details.
AI might be the most important new computer technology ever. It's storming every industry and literally billions of dollars are being invested, so buckle up. The problem is that AI needs a lot of speed and processing power, So how do you compete without cost spiraling out of control. It's time to upgrade to the next generation of the cloud. Oracle Cloud Infrastructure or OCI. OCI is a single platform for your infrastructure, database, application development, and AI needs. OCI has four to eight times the bandwidth of other clouds, offers one consistent price instead of variable regional pricing, and of course nobody does data better than Oracle. So now you can train your AI models at twice the speed and less than half the cost of other clouds. If you want to do more and spend less, like Uber eight by eight and Data Bricks Mosaic, take a free test drive of OCI at Oracle dot com slash Strategic that's Oracle dot Com slash Strategic Oracle dot com slash Strategic.
If you love iPhone, you'll love Apple Card. It's the credit card designed for iPhone. It gives you unlimited daily cash back that can earn four point four zero percent annual percentage yield. When you open a high yield savings account through Apple Card, apply for Apple Card in the wallet app, subject to credit approval. Savings is available to Apple Card owners subject to eligibility. Apple Card and Savings by Goldman Sachs Bank USA, Salt Lake City Branch, Member FDIC, terms and more at applecard dot com.
All right, we're asking the question, Daniel, does space have an infinite amount of energy? And I feel like you're telling me the answer is yes.
The math suggests the answer is yes, And if you think about the quantum mechanics of it, it sort of makes sense. Like we know that quantum mechanically things are always wiggling and struggle in and can never really be pinned down. And so if you take a quantum field, it makes some sense for it to always have some uncertainty. And if you had it has exactly zero energy, then you'd know exactly the value the quantum field. And that seems sort of unquantum, you know, just the same way, like you can't have a particle exactly zero energy. You can't have anything at absolute zero and quantum mechanics because then you would know its location and its position. So quantum mechanics says absolute zero is impossible to reach. And this is sort of the same idea that there's a minimum amount of energy that everything has to have, and so space is filled with fields, then those fields have to have some energy.
It's kind of related you were telling me to the idea that the electron can't fall into the nucleus for example, like it can't just collapse into that center.
Yeah, if you solve the quantum mechanics of the hydrogen atom, you have a proton and around it is an electron. You get a bunch of solutions, you get energy levels for the electron, and the minimum energy level is not at zero. It's not oh, the electron falls into the nucleus and is captured. Now, that can actually happen in some other weird states, for example, in the center of a neutron star, or the electron can be forced into the nucleus and then it turns proton into a neutron. But for a normal hydrogen atom, the electron's lowest energy level is not at zero, and it's for the same reason, right, it can't collapse into the nucleus because of the uncertainty principle, because of this zero point energy in its field.
Right. So space is filled with quantum fields, and quantum fields when they don't have particles are in a vacuum, and you're telling me that that vacuum has to have a little bit of energy. So then how do we connect from that to space having infinite energy?
Yeah, So the amazing thing is just take one field. For example, take the photon field, the electromagnetic field. This can have photons of all different frequency, right, frequency, and the visible spectrum frequency, and the X ray spectrum frequency, and the infrared spectrum. It can do all sorts of oscillations. Well, the calculation tells us that the minimum energy in this field is Plank's constant times of frequency over two. This h omega over two. That's the amount of energy for electromagnetic field of that frequency. So that's a certain amount of energy, But there's an infinite number of these frequencies, and so you can have h omega over two for every value of omega from zero all the way up to infinity. So you add up all these little zero point energies and you get an infinite amount of energy. Not an infinite amount of energy in the whole universe, an infinite amount of energy in every piece of space.
I see, you're telling me, like, any little piece of space has a minimum amount of photon energy at one killer herds, and it has a little bit of a photon energy at one point one killer herds, and it has a little bit of energy at one point three killer herds. And so if you add it all up, you're saying that little bit of space has an infinite amount of energy.
Yeah, because there's an infinite number of frequencies and each one has finite energy, and so an infinite sum over finite numbers is infinity. Yeah.
All right, Well this sounds almost too good to be true. I feel like there's some sort of quantum uncertainty, virtual particle kind of fakery going on here.
Well, I'll tell you what physicists usually do is they go, hmm, that's weird. Let's just subtract infinity from everything and ignore it.
We've got an infinity. Let's tamp it down.
Yeah, because for most purposes you're only really interested in relative energy. You're like, can we go up an energy level and absorb a photon? Can we go down an energy level and give off a photon. Most of physics only cares about relative energy, about gaining energy, losing energy, transferring energy. We don't usually care about the actual absolute value of the energy. So in practice we can mostly just ignore this.
We can ignore an infinite amount of energy in every little bit of space.
Yeah, And you can convince yourself like, well, maybe it's some weird quantum thing and we can mostly ignore it and not worry about it. But you know, if you're looking to do something useful with physics and you want to understand the universe at is deepest level, then you can't just ignore it. You got to dig into it. You got to ask yourself, is there a way we could tech this if it were real? Could we do an experiment to figure out if those infinite number of photons are actually there?
M I guess maybe my question is is it real or is it one of these things where there's a little bit of energy at one killer hurts here, But the probability of it is you know, one over infinity or something like that, and so it all sort of cancels out to some finite number.
You're looking to divide infinity by infinity to make it reasonable.
Yeah, it sounds better than putting my thumb over.
It's the same thing mathematically. But no, each of these frequencies should be there, like, at minimum, each of these photon frequencies should exist at h omega over two. And so that's the minimum, right.
Right, But what's the probability that they're actually like a real photon will pop out at that frequency?
The field has that energy according to quantum mechanics, it's there, that's the minimum. So the probability for it to have at least that energy is one hundred percent because that's the minimum energy. Wow, but nobody knows is that real? And we have, on one hand, a fascinating experiment that suggests it might be real, and on the other hand calculations that suggest that's totally impossible for it to be real. So it's a real deep controversy in physics right now.
All right. So that's what this Casimir effect is. It's an experiment that test this idea that this is too good to be true. Infinite energy everywhere idea.
Yeah, this was an idea that was bubbling up after quantum mechanics was invented and developed and people were grappling with the consequences of it. And people first had these kinds of questions like, hold on a second, are you suggesting the universe is built with infinite energy? That can't be true? And so Casimir thought, well, let's try to figure it out. Could I conduct an experiment? Could I devise away a physical system which would reveal if those photons were actually there? So he came up with a really clever idea for a crazy effect, which he called the Casimir effect.
Wait, so it is a real person.
Casimir is a real person.
It would have sounded like a Greek deity or something, you know, or like a Greek.
Nymph may also be but no, a real physicist. But I like that you have in your mind, you know, physicists, nymph it's basically the same category of people.
And yeah, they're all magical beings, all right. So Casimir proposed to Casimir effect, And how do I build one of these things?
It's really hard to build, which is why it was predicted in nineteen forty eight, and then not actually observed for fifty years. But the basic idea is to take two mirrors and have them really really close to each other. You know, we're talking like micron distances, and why does it need to be microns? It needs to be micron distances because what you're trying to do is build a resonant cavity that blocks out most of the photons from the vacuum. So the idea is two mirrors back to back will build something which will enhance photons that have a wavelength that fits right between those mirrors. It's just the way. It's sort of like a laser works or any other sort of resonant cavity. Photons are a wave and they like to bounce back and forth between these mirrors, and so photons that fit very nicely between these mirrors, they'll be enhanced between these mirrors. And every other kind of photon, the ones that don't fit nicely between the mirrors, so like the gap between the mirrors is like one and a half or one point seven wavelengths, they will be suppressed. So that's what a resonant cavity does. And the idea here is if those photons in the vacuum are real, then what you'll do is you'll enhance a specific set of frequencies key to this really small distance, and you'll suppress everything else. Mmm.
I see, it's like a resonant cavity, right. Like if there is sound and noise everywhere and you stuck a little like flute in the middle, it would sort of make a particular sound more prominent.
Exactly, and it will exclude the others. That's the key. He was trying to suppress some of these vacuum modes. He was trying to make a situation where those vacuum modes would disappear. Because what we talked about earlier, the minimum energy of the vacuum being ah of meg over two. That's if you have like nothing around you, that's the vacuum solution. But as soon as you put material in space, then you get different solutions. And this actually suppresses a lot of those modes. So they can't exist between these mirrors. So what you get is some energy between the mirrors, but more energy outside the mirrors. And the difference in that energy, like the fact that you have more photons and more frequencies outside of the mirrors than between the mirrors creates effectively a pressure pushing these mirrors together. Mmm.
I see you create like a little spot in space that only likes one kind of frequency, Yeah, and pushes out all the other frequencies, which then kind of creates pressure inwards like it wants to collapse.
Yeah, exactly. And so that's the idea. You could build these two mirrors, and if the vacuum was real, you're creating a situation where it would actually have a physical effect that you could measure, Like you could put two mirrors near each other, and you could actually measure the force between them. You could see them getting pulled together.
M It's almost like you have a lake and you like try to separate some water out, like carva space in the lake by separating out the water. But then now you have all this water trying to come in, which creates pressure on the walls of your little chamber.
Yeah. Only if there really is water in the lake, right, if you're trying to tell whether there's like invisible water in the lake, This is a way to do it, right, figure out some way to keep the invisible water out of some portion of the lake, and measure is their force now on my chamber. And so that's the idea behind the Castimere effect, Like block the vacuum photons from this little sliver of the universe and see if all the other photons out there try to squeeze it back in.
All right, So you build these two mirrors, you put them in front of each other, and then you what you measure the forces on them.
You measure the forces on them, and this is obviously a very difficult experiment. Like, first of all, making two mirrors that are super duper flat so you can bring them in parallel to each other with very very small distances. Even that is hard. Then you have to isolate it to make sure there are no residual electrostatic charges, because the force of those charges would overwhelm the force of the Castimere effect or gravity or anything else. Right, So you have to do a lot of really just careful experimental work. So people tried for a long time to build this and to make it work, and nobody could get it to work. Like it's just too difficult to see this force. It's expected to be very very small effect.
Yeah, Like what kind of forces are we talking about? Like Pico Newtants.
Yeah, if you had two mirrors with the area of a centimeter squared, and you brought them within a micron of each other. The prediction is that it would have an attractive Cassimere force. It'd pull together like ten to the minus seven newtants, which is about the weight of a water droplet. That's you know, like half a millimeter in diameter. So it's a very small effect.
It sounds small, but it sounds dual for you. This is doesn't men. I mean, you have measured crazy small you know, differences and gravitational waves. You've taken a picture of a black hole really far away. What makes it especially hard it's keeping those two plates parallel, because as soon as they're not parallel anymore, it's not a great resonant cavity. And so people actually tried that for a while and it didn't work. And then there's an innovation. Some guy at Los Alamos, Steve Lemereau, came up with this idea. He said, let's not try it with two plates, let's use one plate and a sphere. And it turns out that a plate and a sphere also has a Casimere effect. The calculation is a little bit different, but still is dependent on the sort of the gap between the sphere and the plate. But a sphere and a plate aren't just much easier to control. You can like bring this little sphere very very close to a very flat surface much more easily than you can keep two plates exactly parallel. I see you build a sphere out of something and then you hold it close to a mirror again or are these mirrors too?
These are mirrors. So you have like a mirrored sphere, it's a nanosphere, and you bring it really close to a surface. And this guy was able to get it within like ten nanometers. That's like, you know, one hundred times the width of a hydrogen atom, So this is pretty close. And he had this technique where he had it sort of on the end of a stick and then he's showing a laser on the back of the mirror, and then you could see very small changes in the location of the sphere based on how the laser bounced off of it. So if the sphere moves a little bit, the laser bounces off at a different angle.
Wow, sounds pretty tough, but I guess my question is how do you know it worked or didn't work? Like if I was trying to build something and measure some invisible water somewhere that I thought was everywhere. How would I know I measured it or didn't.
Measure It's a difficult experiment, and you have to do a lot of work to sort of rule out alternative explanations. Right, you have to rule out is this just an effect of gravity? And so you can calculate, like how big would the gravitational effect be? And see, well, we see something which can't be explained by gravity because the dependence on the distance is different and the overall strength of it is different. And you ensure that it's isolated from electrostatics, and you have all sorts of controls to verify that. So you rule out all other explanations, and essentially what you're seeing is a force that you don't have another explanation for. And you can do calculations that say how strong should this force be? How strong should the Casimir effect be? And when you do those calculations, you predict a force exactly of the strength that these guys measured.
Wait, so this has actually been done and they have measured this effect.
This has been done, and in nineteen ninety seven they measured the Casimir effect. It is real.
Whoa They did measure this invisible water trying to push.
In Yes, exactly, so your faith and physicists was well founded. They figured this out. Only took fifty years, but they did it. And this guy measured this thing, and he's gone on to do all sorts of elaborate extensions on it, making it smaller and closer. It's really pretty impressive. It's just like really cool experimental virtuosity. Wow.
All right, So that means a Casimir effect is real. You can measure it, which would imply that space is filled with infinite energy. But there's a hitch.
That makes absolutely no sense. That's a hitch.
All right. Let's get into whether or not that that makes sense and whether or not it is infinitely possible to have infinite energy in space. But first, let's take a quick break.
When you pop a piece of cheese into your mouth, or enjoy a rich spoonful of Greek yogurt, you're probably not thinking about the environmental impact of each and every bite, But the people in the dairy industry are US Dairy has set themselves some ambitious sustainability goals, including being greenhouse gas neutral by twenty to fifty. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. Take water, for example, most dairy farms reuse water up to four times the same water cools the milk, cleans equipment, washes the barn, and irrigates the crops. How is US Dairy tackling greenhouse gases? Many farms use anaerobic digestors that turn the methane from maneuver into renewable energy that can power farms, towns, and electric cars. So the next time you grab a slice of pizza or lick an ice cream cone, know that try farmers and processors around the country are using the latest practices and innovations to provide the nutrient dense dairy products we love with less of an impact. Visit usdairy dot com slash sustainability to learn more.
With the United Explorer card, earn fifty thousand bonus miles, then head for places unseen and destinations unknown. Wherever your journey takes you, you'll enjoy remarkable rewards, including a free checked bag and two times the miles on every United purchase. You'll also receive two times the miles on dining and at hotels, so every experience is even more rewarding. Plus, when you fly United, you can look forward to United Club Access with two United Club one time passes per year. Become a United Explorer Card member today and take off on more trips so you can take in once in a lifetime experiences everywhere you travel. Visit the Explorer Card dot com to apply today.
Cards issued by.
JP Morgan Chase Bank NA Member FDIC subject to credit approval offer subject to change.
Terms apply.
There are children, friends and families walking writing on halfs some roads every day. Remember they're real people with loved ones who need them to get home safely. Protect our cyclists and pedestrians because they're people too, Go safely. California from the California Office of Traffic Safety and Caltrans.
All right, we're talking about the Casimir effect and whether space has an infinite amount of energy, which experiments say that it should. That everywhere you look, everywhere you are, there is an infinite amount of energy right there underneath the surface there. It is boiling there and bubbling there. But there's another big theory in physics that says this is impossible.
That's right. And this is one of my favorite parts of physics. When you find something in the mathematics that's weird, that seems nonsensible, when you're like, well, that just can't be true, and then experimental physicists go out and say, actually, that's exactly what happens, and so you got to revise your sense of like what can make sense what could be true about the universe. I love when, like, the experiments tell us that the universe is just different from the way we could possibly hold in our heads. That's like an invitation to revise your whole context for how the universe works. Those are the best.
Moments when you're wrong, is what you're saying.
Yes, that's when you learn things when you're wrong. And then the experimentalists come back with this idea and other theorists, the gravitational folks, are like, hold on a second, you should have checked with us, because we could have told you before you discovered this thing that it was impossible.
You should not have a look for it, because now you've proven that our theories are wrong.
Yeah, and here's the problem. We've been talking about space from the quantum mechanical point of view, right, these fields fluctuating and how much energy they have. But as we talked about earlier, there's another view of space, and that comes from gravity and Einstein's theory of general relativity. This beautiful, elegant theory that tells us that gravity is not an attractive force between particles but instead an effect of motion through curved space. Is this beautiful theory because it tells us that space is not just a flat backdrop. There's a dance between energy and space, that the stuff in space tells space how to curve, and that curvature space tells stuff how to move. So it's this awesome, wonderful theory. But that's the key bit. The key bit is that stuff in space, energy or mass, tells space how to curve. Just like if you have a really dense collection of stuff like the Sun, it will bend the space around it, changing the path of things that move near it, such as the Earth. So a lot of energy will bend space.
Right, It's kind of like, you know, if energy is the same as mass, and mass and energy create gravity or distorted space, or you know, pull other masses and other energies, then that means that if there's infinite energy everywhere. It should just be all be pulling, you know, squeezing space everywhere an infinite amount.
Yeah, exactly. There's a problem with having infinite energy in all of space is that it should make everything be basically a singularity, right, you just have infinite curvature everywhere in space. The whole universe is basically a singularity inside a black hole. And that's not what we see, right, we don't see space being infinitely curved. It doesn't really make any sense. One guy, just after the Casimir effect came out, sat down to do this calculation and say, well, is it possible. Is there a way to like actually solve general relativity and have an infinite amount of energy? You know, maybe everything's just like tightly balanced. But he did the calculation and he found that if this were true, if there was this much energy, then the whole universe would be so curled up it would be smaller than the moon.
Well, isn't that a theory also that we are sort of living in a singularity inside of a black hole, that maybe our universe is inside some other universes black hole and then make a plausible thing.
There are some theories that you know, perhaps our universe is a connection to other universes, and that at the core of black holes there are singularities which can connect us to them, or perhaps even our entire universe is inside another universe. But you know, we don't see locally crazy infinite curvature. If that were true, if we were inside a singularity itself, not just like inside the event horizon of a huge black hole. If we were actually inside a singularity, space would have infinite curvature, and that would have real consequences for how things moved. Right, we can measure their local curvature or space because we see how things move and curve, and we do not see infinite curvature. So we're pretty confident that we're not living in a singularity.
Right. But you know, I feel like this tells you that there's infinite energy in an infinite amount of places everywhere. So wouldn't all those effects kind of cancel out, you know, like everywhere is a singularity. Wouldn't that flatten out in a way?
Yeah? And it's a little bit more complicated because the way that general relativity works is it's not just like mass curve space, and it's not exactly just that like any energy density curves space, including mass. There's this thing called the stress energy tends which tells space how to curve. And it's so sensitive not just to the amount of energy and the amount of mass, but sort of like the arrangement of it. So you can have, for example, angular momentum contributes to it, and all sorts of complicated effects, and we don't need to go through the calculation here, but it does lead to infinite curvature rather than an equal balance all through space. There is a difference. It's not just relative energy. The absolute energy is actually important for general relativity.
M all right. So it seems that we have kind of a big problem because a real experiment, like an actual thing we can measure, tells us or suggests that there is infinite energy everywhere, but our theory of the universe says that's not possible. So like, who do you believe what you can see with your eyes or what the theory tells you?
We just really don't know. This is like a big open question in physics, you know, And remember that quantum mechanics and general relativity are sort of the two pillars of physics and don't really agree on a lot of stuff I don't agree about what does a singularity look like inside a black hole? But most of the places they disagree are really hard to get to, really hard to explore, like the heart of a black hole. So this is an opportunity to help try to resolve this question. Is quantum mechanics view of the universe correct? Or is general relativity correct? It's an opportunity to resolve this question in a place where we can actually do experiments in our lab. We can see these two things conflict. Quantum mechanics says, no, the universe is filled with energy in every space, and look, I'm right, here's an experiment that proves it. General relativity says that's nuts and it can't possibly be right. Otherwise things would be crazy. And so what do we do? We try to come up with another theory, a theory that unifies these two that explains what we see and make sense of it. We don't have that theory today, but this is like a great clue that tells us if you're going to build that theory, you have to somehow explain the Cacimer effect. You can't just subtract the way of that infinity. And also you have to subtract with that infinity so that you don't curve space too much.
I see. So, like, you know, we measured this effect. It's real. It's real, but it may not mean that space is filled with infinite energy. It might be that our theory, which you know, ties that experiment to this idea of infinite energy, could be wrong.
Yeah, exactly. Now it's interesting because the predictions for the Casimir effect, when you start from that quantum theory, they predict the effect at the level that you see it. So that's pretty convincing. Now, there are some other attempts to explain these Casimir effect experiments without using quantum zero point energy. For example, people say maybe it's just a misunderstanding of the Vanderwall's force, and people have done some calculations to suggest that, you know, relativistic corrections, small corrections to the way we think about the vander Walls force might account for the Casimir effect. It's like an attempt to describe it using other physics that doesn't break general relativity.
I see.
So far are those calculations though they're cool, and they do suggest and effect is there don't agree with what we've measured so far. So they can't really explain the experiments. It doesn't really solve the problem yet. But you know, this is like active research. Is somebody out there right now like improving those calculations trying to describe what we see out there without including quantum infinite photons.
So I see, like what we measure may not be an effect of quantum physics, which is something else.
Yeah, it could be something else exactly. And that's the struggle, like do you come up with another theory to explain this real experimental effect that doesn't break general relativity or you try to figure out like, hey, maybe general relativity is wrong and you know, we need another theory that includes quantum effects and somehow doesn't bend space in the universe.
Right, Well, it seems to me like the consequences of this question are huge, right, Like this could determine whether quantum physics is right or relativity is right, And it seems really important, almost like you know how we talk about the center of black cold being really important because they would settle this question. But it doesn't seem like physics is very focused on this little effect here, you know, And I feel like there's more attention paid to black holes and then there is to the Casimir effect.
Well, black holes are sexier than like tiny microspheres next to tiny microplates, you know. But this is a really active area of research, and you're totally right, it's a huge opportunity. It's much more exciting than black holes because it's real and we can test it and we can explore it. But it's also very very difficult, sort of in the way the black holes are. Like these Casimir effect calculations, they are hard. We don't know how to do them for lots of configurations. Like it's an open question right now. If you build a mirror that was a sphere and you had photons bouncing around inside that sphere, would that have a Casimir effect, would implode the sphere or would explode the sphere like theorists do calculations and get different numbers. So it's a really sort of technically very difficult area to make progress in, both experimentally and theoretically. But I think inside physics it's widely recognized as an amazing opportunity to maybe clear up this question of quantum mechanics versus general relativity. Yeah, and their press folks should definitely get on social media.
Yeah, because you know, as we heard from our listeners, almost nobody had heard of it.
Yeah, and you know what, they should have gotten in touch with a Game of Thrones folks and made it the reins of Casimir instead. That would have been a great cross marketing opportunity.
Yes, you can picture it. It's a wedding, and relativity walks in thinking that, you know, it's a happy event, and then quantum mechanics pulls an if.
No, I was thinking that the Jester could do some trick with a Casimir effect and two thin plates or something, you know, after dinner entertainment. But yeah, you know, go down that road. If Throat's being slitcher.
Well, it is Game of Thrones. I mean, somebody has to meet their demise.
It's either going to be general relativity or quantum mechanics. Somebody will perish.
When you play the game of physics, you're either right or.
You're wrong, yeah, or you're quantum mechanicalized.
All right, Well, I hear the rains of customer playing. I feel like I think we are near the end of here, of our episode where we learned that the space might have an infinite amount of energy, and there's an experiment to prove.
It absolutely, and this Casimir effect is super fascinating. It could also, since it's real, help us build super tiny electronics with actual moving little parts at the nanoscale. Some people suggested that we might be able to use the Casimir effect and in a repulsive way, to keep wormholes open to keep them from collapsing if it's real. So not only is it a fascinating question which might reveal the ultimate nature of reality, it also could help us travel the universe.
Wow, that is definitely more interesting than black holes.
And less deadly.
All right, Well, once again we learned that there is more to the universe than we realized. That there might be energy kind of in the air, in the space between us, between our particles, and this might even be an infinite amount of energy, which means there's potential for anything in this universe.
That's right, But don't let your iPhone batteries good as zero just yet. We haven't perfected vacuum charging.
Yeah, just wave it around in the air and see if that works.
Do your own Casimir experiment at home.
All right, Well, we hope 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 iHeart Radio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. When you pop a piece of cheese into your mouth, you're probably not thinking about the environmental impact. But the people in the dairy industry are. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. House US dairy tackling greenhouse gases, Many farms use anaerobic digestors to turn the methane from manure into renewable energy that can power farms, towns, and electric cars. Visit you as dairy dot COM's Last Sustainability to learn more.
As a United Explorer Card member, you can earn fifty thousand bonus miles plus look forward to extraordinary travel rewards, including a free checked bag, two times the miles on United purchases and two times the miles on dining and at hotels. Become an Explore and seek out unforgettable places while enjoying rewards everywhere you travel. Cards issued by JP Morgan Chase Bank NA member FDIC subject to credit approval offer subject to change terms apply.
There are children, friends, and families walking, riding on paths and roads every day. Remember they're real people with loved ones who need them.
To get home safely.
Protect our cyclists and pedestrians because they're people too. Go safely, California From the California Office of Traffic Safety and Caltrans
