Episode Transcript
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Speaker 1 (00:08):
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
(00:31):
ideas about that. 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 or Hamming, cartoonists and the creator
(01:01):
of PhD comics. Hi, I'm Daniel. I'm a particle of physicist,
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 potentially infinite number of fluctuating particles
(01:24):
popping in and out of the vacuum. We're mathematically infinite.
The vacuum of space always full of surprises. I feel
like Yeah, like you never know what it's gonna 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 I Heart Radio, in
which we examine the infinite with a cold eye. We
(01:46):
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.
(02:09):
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? Doesn't make sense? Is it possible for
humans to make sense of it? Yeah? Because it is
(02:30):
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 were 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.
(02:51):
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,
(03:13):
for example. So it's a pretty weird thing. Yeah, And
not only could the universe be infinite, you 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,
(03:33):
it might tell you something very strange. So to be
on the podcast will 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
(03:54):
papers about the fabric of reality and just get us
that air charger. All right, I'm to 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 the air, the iMac vacuum
you go. But I think this touches on something which
is really at the heart of what we're doing with
(04:16):
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 the 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
(04:38):
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
(04:58):
have zero energy in them. And so according to quantum 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
(05:18):
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 this a really
interesting experiment that studies something called the Cassimir effect, which
might be sensitive to whether these particles really are out there.
And this experiment tells us something amazing. Yeah, the Cassimir
effect is a really interesting well just the name, and
(05:39):
I have to say, at first, I thought it was
sort of a reference to the reins of Castimir, and
I thought, oh, that's not going to end well for
this podcast. Are We're gonna end up at the red
wedding at the end of this, I hope not be
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 for dicted a long time
(06:00):
ago and recently observed. Yeah, it's an idea that's been
around for a long time, like over a 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.
(06:23):
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'll be,
were wondering how many people had even heard of this
experiment or effect, and so Daniel went out there into
the wild to the internet to ask people what is
the Casimir effect? So thanks to everybody who participated with
(06:44):
so much evident joy and enthusiasm. If you would like
to speculate baselessly and without reference materials on future questions
for the podcast, please write to us two questions at
Daniel and Jorge dot com. So before you listen to
these answers, think about it for a second. If so,
gonna ask you, what is the Casimir effect? Not the
range of Casimir? What would you say? Here's what people
(07:06):
had to say. It makes me think of something to
do with sons. So maybe sun flairs 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
(07:27):
an effect that perhaps had not been noticed before. To
see the customer effect, you put two metallic plates close together.
Then they move even closer together because the number of
particle anti particle or virtual particle antiparticle pairs outside the
place as greater than those between the plates. So the
(07:51):
particles outside exert a non zero net force on the plates,
and they moved closer together. Most 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 Kastimir. Maybe are fantasy fan and
physics loving audience doesn't overlap. But there were some pretty
(08:11):
good guesses here. I like the it was named after
a guy named Casimir. 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 Cassimir and his PR team
definitely needs some like social media tips well step us
(08:34):
through this, Daniel. First of all, Yeah, what is this
idea that space is filled with energy? It's a really
sort of bonkers 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
(08:56):
person that thinks, well, space is nothing right, spaces, emptiness, spaces,
the gap between stuff, then remember that modern physics is
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 gonna
put that aside today and we're gonna look at the
quantum physics view of space. The quantum physics view of
(09:18):
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.
(09:41):
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. Yeah, exactly. And I think
(10:01):
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,
(10:23):
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 that would be the quantum field, and the electron
is like a little bump in the blanket that you know,
kind of moves around. That sounds pretty cozy. Your theory
(10:44):
of the universe doesn't sound like cold and empty. It
sounds like snuggly and a cold, rainy day. It's called
a cozy effect exactly, 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
(11:04):
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
(11:25):
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
(11:46):
for every possible particle. So every point in space has
an electron field, and muan field, a cork 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 particles
don't interact with each other, and so these fields don't
interact with each other, but sometimes they do. For example,
(12:08):
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 to sown a little bit with other blankets. Yeah, exactly.
If you make a wiggle in one, it will spread
that energy out into others, and some of them slash
(12:28):
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 is 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
(12:50):
a whole different podcast. For today, the thing we need
to think about is what it means when these fields
are emptiest m 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 it's space the
empty warehouse and then you put fields in it. Or
do you think of it that you can't have space
(13:11):
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
(13:31):
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 context,
that would be quantum gravity. So quantum mechanics views space
is sort of like flat and absolute, and then you
(13:53):
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
(14:16):
quantum mechanics, that meant zero. Like if you had an
electromagnetic field classically, like a 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. 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
(14:38):
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
(15:00):
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. Doesn't mean that there are like little
(15:22):
virtual particles actually there with real energy. Is it a
weird mathematical artifact that we're just not understanding as it
acclude into something else, like what does this actually mean?
Is the heart of the question. I guess what what
do you mean it can't have zero energy? Like it
it's not likely or it's just like theoretically possible, it
would break some kind of math equation, And what does
it mean? Like, how do you know it can't have
(15:43):
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 in electron and can
do I don't know exactly which one it's going to
do when I can tell you the probabilities of various ones,
(16:04):
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. I mean you solve the
quantum mechanics of a system in 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
(16:28):
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. All right, we're asking the question, Daniel,
(17:02):
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 wiggle
in and struggle in and can never really be pinned down.
(17:22):
And so if you take a quantum field, it makes
some sense for it to always have some uncertainty. And
if you had it have exactly zero energy, then you'd
know exactly the value of 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
(17:44):
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're telling
me to the idea that the electron can't fall into
(18:04):
the nucleus for example, like it it can't just collapse
into 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
(18:24):
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
the proton into a neutron. But for a normal hydrogen atom,
the electrons 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
(18:45):
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? So the amazing thing is just take
one field. For example, take the photon field, the electromagnetic field.
(19:07):
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 planks constant times of frequency over two h
omega over two. That's the amount of energy for electromagnetic
(19:30):
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
(19:51):
amount of energy in every piece of space. I see
you tell me, like, any little piece of space has
a minimum amount of 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.
So if you add it all up, you're saying that
(20:12):
a 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 some 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
(20:34):
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
(20:55):
go down 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,
(21:15):
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 that is deepest level, then you can't
just ignore it. You gotta dig into it. You gotta
ask yourself, is there a way we could detect this
if it were real? Could we do an experiment to
figure out if those infinite number of photons are actually there?
(21:40):
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,
(22:01):
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.
(22:22):
So the probability for it to have at least that
energy is because that's the minimum energy. 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. Right. So that's what this Casimir
(22:45):
effect is. It's an experiment that tests 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 build with infinite energy. That can't be true,
(23:06):
and so Cassimir thought, well, let's try to figure it out.
Could I conduct an experiment? Could I devise a way
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 Cassimir
effect weight. So it is a real person. Cassimir is
a real person. It should have sounded like a Greek
(23:26):
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. Yeah, they're
all uh, magical beings. Alright. So Cassimir proposed the Casimir effect,
And how do I build one of these things? It's
(23:47):
really hard to build, which is why it was predicted
in 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
(24:10):
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
(24:31):
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,
(24:53):
then what you'll do is you'll enhance a specific set
of frequencies, you know, key to this really small distance,
and you'll suppress every anything else. I see. It's like
a resonant cavity. Right, like if there was 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
(25:16):
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 h and mego
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 and you get different solutions, and this
actually suppresses a lot of those modes. So they can't
(25:39):
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 the mirrors
than between the mirrors, creates effectively a pressure pushing these
mirrors together. I see, you created like a little spot
in space that only like one kind of frequency, and
(26:01):
push this 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
(26:24):
could see them getting pulled together. 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
(26:46):
is the way to do it. Right, figure out some
way to keep the invisible water out of some portion
of lake, and measure is their force now on my chamber.
And so that's the idea behind the castome 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. All right, So you build
(27:06):
these two mirrors, you put them in front of each other,
and then you would 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 it's hard. Then you have to isolate it
to make sure there are no like residual electrostatic charges,
(27:27):
because the force of those charges would overwhelm the force
of the castomere effect or gravity or anything else. Right,
So you have to do a lot of really just
careful experimental work. So people try for a long time
to build this and 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 already talking about, like Pico Newton's. Yeah,
(27:51):
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 castomer for so it pulled together like tend the
minus seven Newton's 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
(28:13):
it sounds dual for you. This does, man, 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 this especially hard it's keeping those two plates parallel.
Because as soon as they're not parallel anymore, it's not
a great resident cavity. And so people actually tried there
(28:33):
for a while and didn't work. And then there was
an innovation. Some guy at Los Almos, Steve Lamereaux, came
up with this idea. He said, let's not try it
with two plates. That's use one plate and a sphere.
And it turns out that a plate and a sphere
also has a Casimer effect. The calculation is a little
bit different, but it still is dependent on the sort
of the gap between the sphere and the plate. But
(28:54):
a sphere and then 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 can build a sphere out of something and then
you hold it close to a mirror again or these
mirrors to these are mirrors, so you have like a
(29:14):
mirrored sphere, it's a nano sphere, 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,
a 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 he could see very small
(29:35):
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.
(29:56):
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,
(30:19):
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,
(30:41):
so this has actually been done and they have measured
this effect. This has been done, and in seven they
measured the Casimir effect. It is real. Well, 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 he did it.
And this guy measured this thing, and he's gone on
(31:02):
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. All right, So that means
a Cassimer effect is real. You can measure it, which
would imply that space is filled with infinite energy. But
(31:23):
there is a hitch that makes absolutely no sense that. Alright,
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. Alright,
(31:51):
we're talking about the Casimer 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. They're
just boiling their bubbling there. But there's another big theory
(32:11):
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 nonsensical,
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
(32:33):
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. There's 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
(32:55):
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 look for it because now 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
(33:17):
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.
(33:38):
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
(33:59):
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 distored space, or you know,
pull other masses and other energies, then that means that
(34:22):
if there's infinite energy everywhere, it should just be I'll
be pulling, you know, squeezing space everywhere an infinite amount. Yeah, exactly.
There's a problem with having infinite energy into 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
(34:45):
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 Customer effect came out, sat down to
do this calculation and say, is it possible. Is there
a way to like actually solve general relativity and have
an infinite amount of energy? You know, maybe everything is
just like tightly balanced. But he did the calculation and
he found that if this were true, if there was
(35:06):
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 universe is black hole,
And then like a plausible thing, there are some theories that,
you know, perhaps our universe is a connection to other
(35:26):
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
(35:46):
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
(36:07):
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
(36:29):
curves space, including mass. There's this thing called the stress
energy tensor which tells space how to curve, and it's
so it's 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 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 equal
(36:51):
balance all through space. There is a difference. It's not
just relative energy. The absolute energy is actually important for
general relativity. Alright. So it seems that we have a
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
(37:13):
the universe says that's not possible. So, like, who do
you believe what you can see with your eyes or
what your 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. You know, they don't agree
(37:34):
about what does the 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
(37:55):
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 of theory
(38:16):
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 gonna build that theory, you have to somehow
explain the Casimer effect. You can't just subtract the way
that infinity and also you have to subtract away that
infinity so that you don't curve space too much. I see. So,
(38:37):
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,
(38:58):
they predict the effect at a level that you see it,
So that's pretty convincing. Now, there are some other attempts
to explain these Cassimir 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
(39:22):
to the way we think about the Vanderwall's force might
account for the Cassimir effect. It's like an attempt to
describe it using other physics that doesn't break general relativity
so far. 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.
(39:42):
That 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. I like,
what we measure may not be in effect of quantum physics,
but just something else. Yeah, it could be something else exactly,
(40:03):
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
(40:24):
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 holes
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 there is to
(40:44):
the Cassimere 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,
is 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
(41:08):
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 there
is du calculations that get different numbers. So it's a
really sort of technically very difficult area to make progress in,
(41:30):
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
(41:51):
Thrones folks and made it the reins of Casimir instead.
That would have been a great cross marketing opportunity. Yes,
you can picture it. Its wedding and relativity us in
thinking that, you know, it's a happy event and then
quantum mechanics pulls a knife. No, I was thinking that
the Jester could do some trick with a Cassimir effect
and too thin plates or something, you know, after dinner entertainment.
(42:12):
But yeah, you know, go down that road if through
its being slitcheder what 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,
(42:33):
I hear the reigns of customer playing. I feel like
I think we are near the end the 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.
You could also, since it's real, help us build super
tiny electronics with actual moving little parts at the nanoscale.
(42:54):
Some people suggested that we might be able to use
the Casimir effect and in a repulsive way to keep
worm holes 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 hole and less deadly. All right, well, once
(43:17):
again we learned that there's more to the universe, and
we realized that there might be energy kind of in
the error 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 go to zero just yet.
We haven't perfected vacuum charging. Yeah, just wave it around
(43:39):
in the air and see if that works. Do your
own customer 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 explained.
The Universe is a production of Heart Radio. For more
(44:01):
podcasts for my Heart Radio and visit the I Heart Radio,
Apple Apple Podcasts, or wherever you listen to your favorite shows.