Speaker 1: Welcome to the quark Side. Quantum Physics podcast, an exploration
Speaker 1: of the fundamental structure of reality, where quantum laws govern matter, energy,
Speaker 1: and information. Here, uncertainty is a feature, not a flaw,
Speaker 1: and understanding begins at the smallest scales.
Speaker 2: I want you to try something with me. It's a
Speaker 2: mental exercise I do sometimes when I can't sleep.
Speaker 3: Oh boy, okay, I'm listening.
Speaker 2: Imagine you are standing in the middle of the Great
Speaker 2: Basin desert, just you, the silence, and the ground beneath
Speaker 2: your feet. It's midnight, no moon. You look up.
Speaker 3: I know this view. It's one of the most humbling
Speaker 3: views on.
Speaker 2: Earth, it really is. You see the Milky Way arching
Speaker 2: over you. You know that dense river of stars. You
Speaker 2: see Jupiter, maybe Mars, but mostly, if you're being honest
Speaker 2: about what your eyes are actually registering, you see black darkness. Yeah,
Speaker 2: sheer darkness, right, vast crushing darkness. And our brain has
Speaker 2: a very specific default setting for interpreting that darkness. We
Speaker 2: look at the space between the stars and we think
Speaker 2: that is empty.
Speaker 3: It's the ultimate intuitive assumption. I mean, it makes perfect sense.
Speaker 3: If I take a box and I pump out all
Speaker 3: the air, sweep of the dust block the light and
Speaker 3: I don't know shield it from magnetic fields. I have
Speaker 3: an empty box. I have nothing.
Speaker 2: And for most of human history that was it. That
Speaker 2: was the assumption. The void is just well, it's the
Speaker 2: absence of stuff. But today we're going to take a
Speaker 2: sledgehammer to that intuition, because it turns out that empty
Speaker 2: box doesn't exist.
Speaker 3: It really really doesn't.
Speaker 2: We're going to explore the quantum vacuum, and the headline,
Speaker 2: which sounds completely contradictory, is that nothing is actually something.
Speaker 2: In fact, empty space might be the most active, chaotic,
Speaker 2: and energetic thing in the entire universe.
Speaker 3: It's a foundation of reality. That's not an exaggeration. It's
Speaker 3: not just a backdrop the action. It's a seating ocean
Speaker 3: of activity that shapes atoms, that evaporates black holes, and
Speaker 3: might even be responsible for the Big Bang itself.
Speaker 2: So if you could actually see what's happening in those
Speaker 2: dark patches of the night sky, you wouldn't see emptiness
Speaker 2: at all.
Speaker 3: No, you'd see a riot.
Speaker 2: All right in the void. I love that image. But
Speaker 2: before we get to the kaas, we have to, you know,
Speaker 2: respect the history here, because for a long time, the
Speaker 2: smartest people on Earth. We're talking Newton, gal Leo. They
Speaker 2: were firmly on team empty.
Speaker 3: Oh. Absolutely, And it makes sense, doesn't it. This is
Speaker 3: what we call the classical view. Think about Isaac Newton.
Speaker 3: For him, space was a stage, a stage, a passive,
Speaker 3: wooden stage. The actors were the planets, the stars, you know,
Speaker 3: the apples falling from trees. They moved around on the stage.
Speaker 3: They bumped into each other, gravity pulled them this way
Speaker 3: and that. But the stage itself, it did nothing. It
Speaker 3: was just the container, an inert, passive background.
Speaker 2: So it was just there. If you kicked all the
Speaker 2: actors off the stage, if you somehow removed all the
Speaker 2: matter and energy from the universe, the stage would just
Speaker 2: sit there, existing but completely dead.
Speaker 3: Exactly in classical physics, and this includes Maxwell's incredible work
Speaker 3: on electromagnetism later on, the definition of empty was basically
Speaker 3: a mathematical zero.
Speaker 2: No particles, no particles, tell us no radiation, well us
Speaker 2: no radiation.
Speaker 3: And that equals a zero field value. That equals truly
Speaker 3: fundamentally empty.
Speaker 2: And to be fair, this view worked. It worked beautifully
Speaker 2: for centuries.
Speaker 3: It did. It predicted planetary orbits with stunning accuracy. It
Speaker 3: let us build bridges, design machines. There was absolutely no
Speaker 3: reason to doubt.
Speaker 2: It until the twentieth century showed up and decided to
Speaker 2: ruin everyone's simple, organized life or make it infinitely more fascinating,
Speaker 2: depending on how much you like linear algebra. I guess,
Speaker 2: so the quantum revolution happens. What was the specific thing,
Speaker 2: the smoking gun that killed the idea of the empty container?
Speaker 3: It wasn't one single discovery, but it all hinges on
Speaker 3: one fundamental rule, a pillar of the whole theory. Yeah,
Speaker 3: the Heisenberg uncertainty principle.
Speaker 2: Okay, I know this one, or I think I do.
Speaker 2: This is you can't know where a particle is and
Speaker 2: how fast it's going at the same time.
Speaker 3: Rule. Right, that's the version most people learn in school,
Speaker 3: and it's absolutely correct position and momentum. But the uncertainty
Speaker 3: principle is actually a much deeper, much broader statement about
Speaker 3: the nature of reality itself.
Speaker 2: So it's not just about position and speed, not at all.
Speaker 3: It applies to other pairs of properties too, You can
Speaker 3: think of them as complementary variables. And the one that
Speaker 3: completely breaks the concept of nothing is the relationship between
Speaker 3: energy and time.
Speaker 2: Energy and time, So you can't know the energy and
Speaker 2: the time simultaneously. That sounds a little more abstract.
Speaker 3: It is, but think of it like photography. You know,
Speaker 3: if you're trying to take a picture of a fast
Speaker 3: moving car, you need a really really fast shutter speed
Speaker 3: to freeze the action right.
Speaker 2: If the shutter is open too long, the car is
Speaker 2: just a blur. If it's open for a millisecond, the
Speaker 2: image is crisp, exactly.
Speaker 3: But there's a trade off, isn't there. To get that
Speaker 3: crisp frozen moment that is a super precise measurement of time,
Speaker 3: you have to let in very little light. You lose
Speaker 3: information about the scene, about the energy of the photons
Speaker 3: because your window is so short.
Speaker 2: Okay, I'm following.
Speaker 3: The uncertainty principle is like the ultimate unbreakable shutter speed
Speaker 3: limit for the universe.
Speaker 2: So how does that apply to energy.
Speaker 3: Well, the formula states that the uncertainty and energy we
Speaker 3: call it delta e multiplied by the uncertainty in time
Speaker 3: delta T must be greater than or equal to a
Speaker 3: specific tiny number half of planks.
Speaker 2: Constant, which is a famously tiny number.
Speaker 3: It is incredibly tiny, But the crucial part is that
Speaker 3: it is not zero, and that distinction, that tiny non
Speaker 3: zero value changes everything.
Speaker 2: Okay, so what does that tell us?
Speaker 3: It tells us that nature forbids you from knowing the
Speaker 3: exact energy state of a system if you look at
Speaker 3: it for a brief enough window of time.
Speaker 2: So if I try to take an incredibly fast snapshot
Speaker 2: of empty space, the image.
Speaker 3: Of the energy becomes blurry. It has to. The uncertainty
Speaker 3: in the energy explodes to compensate for the certainty in
Speaker 3: the time. It means that on very very short time scales,
Speaker 3: the energy of any specific point in space must fluctuate.
Speaker 2: Hang on, must fluctuate. You don't mean it can fluctuate?
Speaker 3: No, I mean must. It's a requirement. Nature literally does
Speaker 3: not have a zero setting that it can hold for
Speaker 3: a fixed short period of time. A precise energy of
Speaker 3: zero for a precise time interval violates the uncertainty principle.
Speaker 2: So empty space isn't sitting at zero energy. It can't.
Speaker 3: It can't. It's jittering, it's vibrating around zero, frothing, seething,
Speaker 3: pick your verb.
Speaker 2: And this isn't a measurement problem, right, It's not that
Speaker 2: our tools are bad and we just can't detect the stillness.
Speaker 3: No, absolutely not. This is one of the hardest things
Speaker 3: to grasp about quantum mechanics. The fuzziness is a fundamental
Speaker 3: property of reality itself. The universe is inherently uncertain at
Speaker 3: this level.
Speaker 2: So even if you clear out all the matter, all
Speaker 2: the radiation, there's still something there.
Speaker 3: The quantum fields are still there, the electromagnetic field, the
Speaker 3: Higgs field, all of them. You can't comgri to the fields.
Speaker 3: They are the fabric of space, and because of this uncertainty,
Speaker 3: those fields are constantly vibrating.
Speaker 2: Okay, so we have energy fluctuating in empty space.
Speaker 3: It's buzzing.
Speaker 2: But Einstein taught us something pretty important about energy, right,
Speaker 2: the famous one e mc two two, the.
Speaker 3: Most famous equation in history. Energy equals mass times the
Speaker 3: speed of light squared.
Speaker 2: Which means energy and mass are two sides of the
Speaker 2: same coin. They are, for all intents and purposes, interchangeable.
Speaker 3: Precisely, And this is where the pop up universe comes
Speaker 3: into play. If you have energy fluctuations in the vacuum,
Speaker 3: and energy can become.
Speaker 2: Mass, then the vacuum isn't just fluctuating with abstract energy.
Speaker 2: It's fluctuating with mass with particles. This is the part
Speaker 2: that always sounds like science fiction to me. I mean,
Speaker 2: it just sounds impossible. You're talking about virtual particles.
Speaker 3: Yes, virtual particles, ephemeral, fleeting, but very real.
Speaker 2: So let's be very very specific here. I'm looking at
Speaker 2: that empty box we talked about, the one we pumped
Speaker 2: all the air out of. What is actually happened inside it?
Speaker 2: Right now?
Speaker 3: Okay, picture a particle and its antiparticle. The classic example
Speaker 3: is an electron and a positron, which is an anti electron. Okay,
Speaker 3: out of absolutely nowhere. The vacuum spontaneously borrows a tiny
Speaker 3: bit of energy from itself to create this pair. They
Speaker 3: pop into existence out of nowhere.
Speaker 2: There's no source.
Speaker 3: The source is the uncertainty of the quantum field itself.
Speaker 3: It's a loan from the universe's energy bank. So they appear,
Speaker 3: they exist for an incredibly brief moment, and then snap,
Speaker 3: they find each other. They could pull back together.
Speaker 2: And annihilate, and they give the energy back.
Speaker 3: They return the energy they borrowed back to the vacuum.
Speaker 2: The books are balanced, so it's like a bank loan,
Speaker 2: a cosmic.
Speaker 3: Overdraft, a very very high frequency, high risk bank.
Speaker 2: Loan, yes, and the uncertainty principle is the bank manager
Speaker 2: setting the terms of that loan.
Speaker 3: That is a perfect analogy. The rule is the more
Speaker 3: energy you borrow, which means the heavier the particles you create,
Speaker 3: the faster you have to pay it back.
Speaker 2: So you can make a big heavy particle.
Speaker 3: Can borrow enough energy to make say a top quark
Speaker 3: in an anti top quark, which are incredibly massive, but
Speaker 3: you might only have a trillionth of a trillionth of
Speaker 3: a second to exist before you have to annihilate and
Speaker 3: pay the debt.
Speaker 2: That seems incredibly convenient. I have to be honest, Hey,
Speaker 2: these particles exist, but they disappear so fast you can't
Speaker 2: possibly see them. It feels like a mathematical trick, like
Speaker 2: some physicists had a bookkeeping error in their equations and
Speaker 2: just gave it a cool name to cover their tracks.
Speaker 3: Well those were yeah, virtual particles. Don't worry about them exactly,
Speaker 3: and that is the healthy skepticism everyone should have. It
Speaker 3: sounds like a cheat code for physics, a fudge factor.
Speaker 3: But here's the thing. They are absolutely real. They are
Speaker 3: not just math. We have physical, experimental proof that they
Speaker 3: are there and that they have consequences.
Speaker 2: Way, give me the smoking gun, because if they disappear
Speaker 2: in ten twenty one seconds or less, how in the
Speaker 2: world are we seeing them.
Speaker 3: We don't see them directly, You're right about that. We
Speaker 3: see their footprints. We see the effects they have on
Speaker 3: the real particles we can see. And the clearest footprint
Speaker 3: of all is found in the simplest atom. There is
Speaker 3: the hydrogen atom.
Speaker 2: The classic one proton, one electron orbiting it right now.
Speaker 3: Think about that electron orbiting the nucleus. In the old
Speaker 3: classical view, that electron is just a simple negative point charge.
Speaker 3: It's a lonely dot moving through a true void.
Speaker 2: Sure simple.
Speaker 3: But in the quantum world, that electron is moving through
Speaker 3: this mosh pit of virtual particles we just described the
Speaker 3: seeding foam.
Speaker 2: The vacuum is buzzing all around.
Speaker 3: It exactly now. The electron is negatively charged. The vacuum, meanwhile,
Speaker 3: is constantly popping with these virtual electron positron pairs. The
Speaker 3: positive virtual positrons in that foam get attracted to our real.
Speaker 2: Electron opposites at fract and.
Speaker 3: The negative virtual electrons get repelled. They're pushed away.
Speaker 2: So the vacuum is reacting to the guest in the room.
Speaker 3: It creates a crowd around it. It forms a polarized
Speaker 3: cloud of virtual particles that swarms around the real electron,
Speaker 3: and this cloud actually shields the electrons charge, It screens it.
Speaker 2: Wait. Wait, so the charge of an electron that we
Speaker 2: measure isn't its real fundamental charge.
Speaker 3: Correct. When we measure the charge of an electron from
Speaker 3: a distance, what we are actually seeing isn't the bear electron.
Speaker 3: We are seeing the electron plus this fuzzy polarized cloud
Speaker 3: of virtual particles that is dampening its effect.
Speaker 2: So the naked electron is actually stronger, much stronger.
Speaker 3: But we can never see it naked. We always see
Speaker 3: it clothed in the vacuum.
Speaker 2: That is wild. It's like a celebrity trying to walk
Speaker 2: through a crowd of paparazzi. You can't see the person clearly.
Speaker 2: You just see this chaotic entourage moving with them.
Speaker 3: That's a perfect analogy, and we can measure this encourage effect.
Speaker 3: It subtly changes the energy levels of the electron in
Speaker 3: the hydrogen atom. It's an effect called lambshift.
Speaker 2: And we can measure that shift.
Speaker 3: We can or we can look at something called the
Speaker 3: magnetic moment of the electron, basically a measure of how
Speaker 3: magnetic it is.
Speaker 2: And how precise is this This is where the proof
Speaker 2: comes in.
Speaker 3: This is it. When we calculate what the magnetic strength
Speaker 3: of an electron should be using just simple quantum mechanics,
Speaker 3: you know, without the virtual particles, we get a number,
Speaker 3: a very precise number, okay, But when we go into
Speaker 3: the lab and we measure it, the experimental value is
Speaker 3: slightly different. It's a tiny bit stronger, and.
Speaker 2: The difference matches the effects of the cloud to.
Speaker 3: An astonishing, almost unbelievable degree. When we use the full
Speaker 3: theory of quantum electrodynamics QED to calculate the influence of
Speaker 3: that virtual cloud, the theoretical prediction matches the experimental measurement to.
Speaker 2: Parts per billion parts per billion.
Speaker 3: It is often cited as the most precise and successful
Speaker 3: prediction in the entire history of science.
Speaker 2: Wow. So, if virtual particles were just a math trick,
Speaker 2: that calculation would be completely wrong.
Speaker 3: It would be completely off. It wouldn't even be close. Yeah,
Speaker 3: the fact that it matches so perfectly tells us that
Speaker 3: the vacuum is alive, that cloud is real. You me
Speaker 3: the chair you're sitting on. Every single electron in our
Speaker 3: bodies is walking around with its own little ghost entourage
Speaker 3: from the vacuum.
Speaker 2: Okay, I'm sold on the app But that's all microscopic,
Speaker 2: it's tiny. Is there any way to see the force
Speaker 2: of nothing on a scale we can actually, you know, visualize.
Speaker 2: Can nothing actually push a physical object?
Speaker 3: It can? And this brings us to one of my
Speaker 3: absolute favorite phenomena in all of physics, the Casimir effect.
Speaker 2: This was discovered theoretically back in nineteen forty eight by
Speaker 2: Hendrick Casimir ra Yes, and.
Speaker 3: At the time people thought it was just a bit
Speaker 3: of a mathematical curiosity. The setup itself is deceptively simple.
Speaker 3: Imagine you take two metal plates, perfectly flat, perfectly reflective,
Speaker 3: and completely uncharged.
Speaker 2: So no electricity, no magnetism, none at all.
Speaker 3: You put them in a perfect vacuum, and you place
Speaker 3: them incredibly close together. We're talking micrometers apart.
Speaker 2: Okay, so two neutral plates floating in the dark. Logic
Speaker 2: says they should just sit there, they have no reason
Speaker 2: to move, nothing should happen.
Speaker 3: Classical logic says nothing should happen. But Casimir did the math.
Speaker 3: He included the quantum vacuum, and he calculated that they
Speaker 3: would actually be pushed together and invisible force would slam
Speaker 3: them shut.
Speaker 2: Why if they aren't magnetic, what's pushing them? Where does
Speaker 2: the force come from.
Speaker 3: It's the vacuum itself. Yeah, the pressure of the void.
Speaker 3: To understand why, we have to stop thinking of these
Speaker 3: virtual particles as little balls for a second and start
Speaker 3: thinking of them as waves. Quantum mechanics says, every particle
Speaker 3: is also a wave, right.
Speaker 2: The old wave particle duality. I'm with you.
Speaker 3: So in the open space outside the plates, virtual waves
Speaker 3: of any size, any wavelength can exist. You can have big, long,
Speaker 3: rolling waves, tiny short, choppy waves. Everything fits. The ocean's
Speaker 3: wide open.
Speaker 2: Right, unlimited possibilities.
Speaker 3: But between the plates it's a tight squeeze. You've created
Speaker 3: a boundary. It's like a guitar string. You can only
Speaker 3: place certain notes, certain wavelengths that fit perfectly between the
Speaker 3: two ends.
Speaker 2: Ah, I see, you can't fit a wave that's bigger
Speaker 2: than the gap between the plates exactly.
Speaker 3: You have physically excluded all the big long wavelength of
Speaker 3: virtual particles from the space between the plates. You filtered
Speaker 3: the mouth.
Speaker 2: So now you have an imbalance huge imbalance.
Speaker 3: You have a full vacuum pushing on the place from
Speaker 3: the outside. All the possible waves are banging against them,
Speaker 3: and you have a restricted vacuum pushing from the inside
Speaker 3: only the small waves that can fit.
Speaker 2: So there's more pressure from the outside.
Speaker 3: It's a radiation pressure difference exerted by nothing. There is
Speaker 3: literally more stuff popping in and out of existence and
Speaker 3: banging against the plates from the outside than from the inside.
Speaker 3: So the net effect is a force pushing the plates together.
Speaker 2: That is actually somewhat terrifying. That empty space exerts real
Speaker 2: physical pressure. If you can exclude enough of it, it
Speaker 2: will crush you.
Speaker 3: And we've measured it. Took a long time. The force
Speaker 3: is incredibly tiny and hard to detect, but in the
Speaker 3: nineteen nineties it was confirmed definitively. It's a real force.
Speaker 3: And you know from modern engineers this isn't just a
Speaker 3: fun theory. Oh how so think about nanotechnology or memes,
Speaker 3: microelectro mechanical systems. These are tiny little machines, gears and
Speaker 3: switches the size of dust.
Speaker 2: Motes like the accelerometer in my phone that detects when
Speaker 2: I turn.
Speaker 3: It exactly that when you build machines that small, the
Speaker 3: parts are incredibly close together, and for years engineers found
Speaker 3: that sometimes these tiny parts would just stick. They would
Speaker 3: clamp together for no apparent reason and get stuck. They
Speaker 3: called it stiction stiiction, and a big component of that
Speaker 3: stiction is the Casimir force. The vacuum is literally trying
Speaker 3: to weld your machine together, So you have to design
Speaker 3: your phone to actively fight against the pressure of the void.
Speaker 2: So nothing is now an engineering constraint on our technology.
Speaker 3: It absolutely is.
Speaker 2: Okay, so we've established the vacuum is energetic, it's buzzing,
Speaker 2: it's real. It pushes plates around. But this leads to
Speaker 2: a massive, massive problem, doesn't it. I've heard this referred
Speaker 2: to as the vacuum catastrophe.
Speaker 3: Oh yes, the cosmological constant problem. This is where this beautiful,
Speaker 3: elegant theory crashes headfirst into reality and explodes in a
Speaker 3: ball of fire.
Speaker 2: Let's get into this. We know there's energy in the vacuum.
Speaker 2: You called it zero point energy, right.
Speaker 3: Zero point just means the lowest possible energy state, As
Speaker 3: we said, thanks to Heisenberg, it's not zero. Now, if
Speaker 3: take queum field theory seriously, you should be able to
Speaker 3: calculate how much energy is in say a coffee cup's
Speaker 3: worth of empty space.
Speaker 2: You just sum up all those fluctuations.
Speaker 3: You add up all the virtual particles, all the waves,
Speaker 3: all the jitters from all the different fields. And when
Speaker 3: physicists do this, they get a number, a truly mind
Speaker 3: bogglingly astronomically huge number.
Speaker 2: How huge are we talking, Well, let's put.
Speaker 3: It in context. Einstein told us energy has mass, and
Speaker 3: gravity pulls on mass. So if the vacuum is full
Speaker 3: of this enormous amount of energy, it should have an
Speaker 3: enormous gravitational pull, right, it should weigh something a lot,
Speaker 3: an incredible amount. If the vacuum really contained the amount
Speaker 3: of energy, the theory predicts, space itself would have so
Speaker 3: much mass energy that it would have instantly crushed the
Speaker 3: entire universe into a black hole fractions of a second
Speaker 3: after the Big Bang.
Speaker 2: Okay, well, looking around, I can confirm that did not happen.
Speaker 2: I'm not currently spaghettified. The universe is still here.
Speaker 3: And not only is it here, it's expanding. In fact,
Speaker 3: observations of distant supernovae tell us it's accelerating. The expansion
Speaker 3: is speeding up.
Speaker 2: And that's driven by dark energy, which is, for.
Speaker 3: All intents and purposes, the measured weight of the vacuum.
Speaker 3: It's the observed energy density of space that is pushing
Speaker 3: the universe apart.
Speaker 2: So we have the theoretical weight what the math says
Speaker 2: the vacuum should weigh, and we have the measured weight
Speaker 2: what the telescope say it actually weighs. What's the difference.
Speaker 3: The discrepancy between the theoretical prediction and the observed value
Speaker 3: is about one hundred and twenty orders of magnitude.
Speaker 2: I'm sorry, did you say one hundred and twenty as
Speaker 2: in a one with one hundred and twenty zeros after it?
Speaker 3: I did a one followed by one hundred and twenty zeros.
Speaker 2: That is, I don't even have an analogy for that.
Speaker 2: If I was an architect and I calculated the load
Speaker 2: bearing capacity of a bridge and I was wrong by
Speaker 2: one hundred and twenty orders of magnitude, I wouldn't just
Speaker 2: be fired. I'd be arrested. The bridge wouldn't just collapse,
Speaker 2: it would turn into a singularity and devour the planet.
Speaker 3: You're not wrong. It is spectacularly epically bad. It is
Speaker 3: often called the worst theoretical prediction in the history of physics.
Speaker 2: So why do we still trust this theory If the
Speaker 2: prediction is that catastrophic, why haven't we thrown the whole
Speaker 2: equation in the trash.
Speaker 3: That is the million dollar question or trillion dollar question.
Speaker 3: Because the theory works perfectly everywhere else. That's what drives
Speaker 3: physicists crazy. It gives us the Lamb shift to parts
Speaker 3: per billion, it predicts the Casimir effect. It's the foundation
Speaker 3: of the standard model of particle physics. It works for lasers,
Speaker 3: for semiconductors, but when you apply it to the universe
Speaker 3: as a whole, it breaks completely.
Speaker 2: So the vacuum works perfectly in the lab, but fails
Speaker 2: spectacularly in the cosmos exactly.
Speaker 3: Some physicists think there's a cancelation mechanism we haven't found,
Speaker 3: some deep undiscovered symmetry that cancels out most of that
Speaker 3: enormous energy, leaving just the tiny, tiny residual bit we
Speaker 3: see as dark energy. Others think our understanding of gravity
Speaker 3: at quantum scales is just fundamentally wrong, But for now
Speaker 3: it remains one of the biggest, most embarrassing unsolved mysteries
Speaker 3: in all of science.
Speaker 2: It's fascinating that the thing holding the secrets to the
Speaker 2: entire universe is the empty space right in front of
Speaker 2: our faces.
Speaker 3: And it gets even more dramatic, even more strange, when
Speaker 3: you take this buzzing vacuum and you put it next
Speaker 3: to the most extreme object in the universe, a black hole.
Speaker 2: Ah. Okay Stephen Hawking territory.
Speaker 3: Yes. In the nineteen seventies, Hawking used this very concept
Speaker 3: of the quantum vacuum to turn our entire understanding of
Speaker 3: black holes completely upside down.
Speaker 2: Before this, black holes were just cosmic vacuum cleaners, right,
Speaker 2: they are the ultimate eaters. Nothing escapes.
Speaker 3: Correct. The event horizon was a point of no return,
Speaker 3: a one way door into oblivion. But Hawking asked the
Speaker 3: simple question, what happens to the vacuum fluctuations right at
Speaker 3: the edge, right at the doorframe of the.
Speaker 2: Black hole, the cliff's edge?
Speaker 3: Precisely? Imagine one of our virtual particle pairs, an electron
Speaker 3: and a positron, popping into existence exactly at the vent horizons.
Speaker 2: Okay, Usually they just snap back together and vanish in
Speaker 2: a flash.
Speaker 3: Usually, but what if in that tiny sliver of time
Speaker 3: they exist, one of them falls into the hole and
Speaker 3: the other one stays just outside.
Speaker 2: They get separated, the cosmic divorce of the sension.
Speaker 3: Wait, the ultimate separation. Yeah, the one inside is captured,
Speaker 3: it's gone forever. The one outside is now alone. It
Speaker 3: has no partner to annihilate.
Speaker 2: With, so it can't vanish. It's been orphaned.
Speaker 3: It can't vanish. To conserve all the laws of physics,
Speaker 3: like momentum and energy, it has to become real. It
Speaker 3: gets promoted from virtual to reel and it zips away
Speaker 3: from the black hole out into space.
Speaker 2: So to an observer far far away, it looks like
Speaker 2: the black hole just spit out a particle.
Speaker 3: Exactly. It looks like the black hole's glowing. It's emitting radiation.
Speaker 3: This is Hawking radiation.
Speaker 2: Well, wait a minute. Energy isn't free. We established that.
Speaker 2: You said, the virtual pair borrows energy from the vacuum.
Speaker 2: If they don't annihilate, the debt isn't paid back to
Speaker 2: the vacuum. So who pays the bill for this newly
Speaker 2: real particle?
Speaker 3: The black hole pays. This is the absolute genius of
Speaker 3: Hawking's insight. The particle that fell in because of the weird,
Speaker 3: intense warping of space time at the horizon. It effectively
Speaker 3: has negative energy relative to the outside universe.
Speaker 2: Negative energy. So the black hole eats a negative calorie.
Speaker 3: That's a great way to put it. It eats a
Speaker 3: negative calorie. By swallowing that one particle with negative energy,
Speaker 3: the black hole's total mass energy decreases.
Speaker 2: So the black hole is paying the energy cost for
Speaker 2: the particle that escaped and became real.
Speaker 3: Yes, and that means the black hole is shrinking, slowly,
Speaker 3: incredibly slowly evaporating.
Speaker 2: That is profound. We used to think black holes were
Speaker 2: these immortal monsters that would just sit there until the
Speaker 2: heat death of the universe. But because of the quiet,
Speaker 2: constant buzzing of the vacuum, they are mortal. They dissolve.
Speaker 3: It takes an unfathomably long time for a big one,
Speaker 3: the google plex years. But yes, they dissolve back into
Speaker 3: the vacuum from whence they came.
Speaker 2: It's ironic, isn't it. The vacuum is the only thing
Speaker 2: that lasts.
Speaker 3: Well, lasts is a strong word.
Speaker 2: Oh no, don't tell me. The vacuum can die too.
Speaker 3: It's not that it dies, it's that it might change
Speaker 3: its mind.
Speaker 2: I do not like the sound of that change its mind.
Speaker 3: You see, We've been assuming that the vacuum state we
Speaker 3: live in, this specific buzz of empty space is the
Speaker 3: bottom floor, the absolute lowest possible energy state, the ground state,
Speaker 3: and it might not be. We aren't sure. This brings
Speaker 3: us to the deeply unsettling concept of vacuum decay.
Speaker 2: This is the cosmic horror part of our exploration today.
Speaker 3: A little bit. Yes, think of a ball sitting in
Speaker 3: a deep valley. It's stable, it's not going anywhere, it
Speaker 3: stays at the bottom. We call that a true vacuum.
Speaker 3: It's as low as.
Speaker 2: It can go right, stable, safe, But what if.
Speaker 3: Our universe isn't in the lowest valley. What if we
Speaker 3: are in a little dip, a small hollow up on
Speaker 3: the side of a much larger mountain. We feel stable,
Speaker 3: the ball isn't rolling, but there is a much deeper valley,
Speaker 3: a lower energy state further down. We call our current
Speaker 3: state a false vacuum.
Speaker 2: So we are just living on a ledge, thinking it's
Speaker 2: the ground floor.
Speaker 3: We might be on a ledge. In classical physics, the
Speaker 3: ball stays put unless you push it. But in quantum
Speaker 3: physics there is a spooky phenomenon called tunneling. The ball
Speaker 3: can without any external push spontaneously tunnel through the ridge
Speaker 3: and drop into the lower valley.
Speaker 2: And in this analogy, the ball is the energy state
Speaker 2: of the entire universe.
Speaker 3: The state of the fundamental fields that make up reality. Specifically,
Speaker 3: the Higgs field is the one we worry about. If
Speaker 3: our vacuum is only the tastable, it could, in theory,
Speaker 3: spontaneously transition to that lower, truer energy state.
Speaker 2: And what happens if that transition trigger somewhere?
Speaker 3: It would start at a single point anywhere, maybe in
Speaker 3: a physics lab, maybe in a galaxy a billion light
Speaker 3: years away. A tiny bubble of tree vacuum would form.
Speaker 3: And because it's a lower energy state it is energetically favorable.
Speaker 3: It would expand.
Speaker 2: How fast would it expand at the speed of light?
Speaker 2: And what's inside the bubble?
Speaker 3: The laws of physics as we know them would be rewritten.
Speaker 3: The fundamental constants of nature, the massive particles like the electron,
Speaker 3: the strength of forces. Everything would change instantly and violently.
Speaker 3: The chemistry that holds your body together would stop working.
Speaker 3: Adams might not even be able to form in that
Speaker 3: new vacuum.
Speaker 2: So it's not an explosion that destroys things it's a
Speaker 2: reformatting of the universe's hard drive.
Speaker 3: That's a perfect description. Matter as we know, it would
Speaker 3: simply cease to be possible inside the expanding bubble.
Speaker 2: And because it moves at the speed of light, we
Speaker 2: would have no warning, we wouldn't see it coming none whatsoever.
Speaker 3: We'd be having this conversation and then simply not be Okay.
Speaker 2: That is genuinely terrifying. How likely is this? Should I
Speaker 2: cancel my dinner plans for tonight?
Speaker 3: No, no, keep your dinner plans. The universe has lasted
Speaker 3: thirteen point eight billion years without this happening, so the
Speaker 3: probability is likely incredibly, incredibly vanishingly low. But there's always
Speaker 3: a butt.
Speaker 2: But the math allows for it. It depends very heavily
Speaker 2: on the precise mass of the Higgs boson and in
Speaker 2: another particle, the top quark. Our current measurements from particle
Speaker 2: colliders put us right on the edge. We seem to
Speaker 2: be in the metastable zone. So technically we are living
Speaker 2: on the edge of a cosmic cliff.
Speaker 3: Great, well, while we are still here in this cozy,
Speaker 3: false vacuum, let's maybe pivot to something a little less apocalyptic. Yeah,
Speaker 3: because as abstract and cosmic as all this sounds, the
Speaker 3: quantum vacuum actually impacts the technology we use every single day.
Speaker 2: Right, absolutely, It's not just for black holes and the
Speaker 2: hypothetical end of the world. It's in your pocket right now.
Speaker 3: You're talking about semiconductor right. The entire electronics industry, every
Speaker 3: computer chip, every smartphone relies on understanding how electrons move
Speaker 3: through materials like silicon. But an electron moving through a
Speaker 3: silicon chip isn't moving through empty space. It's moving through
Speaker 3: a crystal.
Speaker 2: Lattice, a solid block of atoms arranged in a grit, and.
Speaker 3: That lattice that environment modifies the vacuum. When a photon
Speaker 3: of light hits a semiconductor, it can excite an electron,
Speaker 3: leaving a sort of hole behind where it used to be.
Speaker 3: This electron hole pair is itself an excitation that interacts
Speaker 3: with the vacuum fluctuations of.
Speaker 2: The material, the vacuum inside the rock.
Speaker 3: Basically, yes, the optical properties of semiconductors, how they absorb
Speaker 3: into mid light, and how lasers work are all deeply
Speaker 3: influenced by these vacuum interactions. If engineers didn't account for
Speaker 3: quantum field theory, our modern lasers and high speed computer
Speaker 3: chips just wouldn't work the way they do.
Speaker 2: And what about superconductors, those amazing materials that carry electricity
Speaker 2: with zero resistance, zero energy loss.
Speaker 3: That's another even deeper vacuum phenomena. In a superconductor below
Speaker 3: a certain temperature, electrons overcome their natural repulsion and pair
Speaker 3: up into what are called Cooper pairs.
Speaker 2: Which is weird because electrons usually hate each other like
Speaker 2: charges repel.
Speaker 3: Exactly, so how do they suddenly decide to pair up.
Speaker 3: They do it because the vacuum state inside the material
Speaker 3: has fundamentally restructured itself. The crystal lattice deforms in a
Speaker 3: way that creates a sort of attractive force mediated by
Speaker 3: the background vibrations.
Speaker 2: So the background hum of the material actually coaxes them together.
Speaker 3: The underlying symmetry the vacuum breaks, allowing these pairs to
Speaker 3: exist and flow without resistance. So when you get an MRI,
Speaker 3: or you hear about maglev trains or quantum computers, you
Speaker 3: are using technology that relies on a manipulated, restructured vacuum state.
Speaker 3: We are already engineering the void.
Speaker 2: There's also this really weird concept called the Unru effect.
Speaker 2: This one really messes with my head because it implies
Speaker 2: that nothing depends on how fast you're driving.
Speaker 3: It's a beautiful mind bending connection between relativity and quantum mechanics.
Speaker 3: We usually think of emptiness as being absolute. If I
Speaker 3: see a vacuum, you see a vacuum. It should be objective, right.
Speaker 2: Zero particles should be zero particles for everybody.
Speaker 3: But the unrue effect says that if I am floating
Speaker 3: still in space, I see a cold, empty vacuum. But
Speaker 3: if you zoom past me, accelerating at a massive rate,
Speaker 3: you won't see a vacuum. You will see a bath
Speaker 3: of hot particles. You will feel warmth, you will radiation.
Speaker 2: Wait, so I see particles where you see nothing just
Speaker 2: because they hit the gas pedal. Yes, where do the
Speaker 2: particles come from? They can't just appear.
Speaker 3: They come from the vacuum fluctuations. Your intense acceleration pumps
Speaker 3: energy into the system. From your perspective, it's like creating
Speaker 3: a sonic boom. But for the vacuum. You are ripping
Speaker 3: through the virtual particle foam so violently that your detector
Speaker 3: perceives those fluctuations as a real thermal radiation.
Speaker 2: So temperature is relative. The very definition of empty is relative.
Speaker 3: The vacuum of one observer is not the vacuum of another.
Speaker 3: That's the takeaway. If you could build a spaceship that
Speaker 3: accelerated hard enough, you could roast a chicken in what
Speaker 3: another observer would swear is cold empty space, just from
Speaker 3: the friction of the vacuum itself.
Speaker 2: That really challenges the idea of objective reality. The question
Speaker 2: is their particle There has an answer that is, we'll
Speaker 2: check your speedometer first.
Speaker 3: Physics is full of these strange relative truths.
Speaker 2: Let's talk about the strong force for a second. We
Speaker 2: talked about electrons and quantum electrodynamics QED. We said, the
Speaker 2: vacuum screens the charge. It surrounds the electron and makes
Speaker 2: it seem weaker from.
Speaker 3: A distance, right, the entourage effect.
Speaker 2: But I've read that for the forces inside the nucleus,
Speaker 2: for quarks and the strong force, the vacuum does the
Speaker 2: exact opposite it does.
Speaker 3: It's one of the strangest things. This is the realm
Speaker 3: of quantum chromodynamics of QCD, and in QCD, the vacuum
Speaker 3: creates a phenomenon called anti screening or asymptotic freedom.
Speaker 2: Anti screening, so the vacuum doesn't hide the charge, it
Speaker 2: amplifies it.
Speaker 3: It effectively does Yes, the virtual particles in the QCD
Speaker 3: vacuum aren't just quark antiquark pairs. They are also gluons,
Speaker 3: the particles that carry the strong force, and gluons, unlike photons,
Speaker 3: can stick to each other, they carry their own charge.
Speaker 2: They're sticky.
Speaker 3: They're very sticky without getting bogged down. In the deep mathematics,
Speaker 3: the net effect of this gluon filled vacuum is that
Speaker 3: it acts like a tightening rubber band.
Speaker 2: A rubber band.
Speaker 3: How so QEED with electrons, the closer you get, the
Speaker 3: more you pierce that screening cloud, and the stronger the
Speaker 3: effective charge becomes. In QCD with quarks, the closer you get,
Speaker 3: the weaker the interaction seems so.
Speaker 2: When two quarks are right on top of each other
Speaker 2: inside a proton, the.
Speaker 3: Rubber band is slack. They float around almost freely. This
Speaker 3: is asymptotic freedom. It won the Nobel Prize for gross
Speaker 3: will check and Pulitzer because it was so counterintuitive.
Speaker 2: But if you try to pull them apart.
Speaker 3: The vacuum fights you. As you pull two quarks apart,
Speaker 3: the rubber band of the vacuum stretches and the energy
Speaker 3: in the field between them grows. The force gets stronger
Speaker 3: and stronger the farther.
Speaker 2: You pull, so it effectively locks them in it's quark confinement.
Speaker 3: It imprisons them forever. You can never ever pull a
Speaker 3: single quark free from a proton, because to do so,
Speaker 3: you'd have to put an infinite amount of energy into
Speaker 3: the vacuum. Before you could do that, the rubber band snaps,
Speaker 3: but it doesn't release the quark. The energy you put
Speaker 3: into stretching it becomes so great that it's cheaper for
Speaker 3: the vacuum to just create a new pair of quarks
Speaker 3: out of thin air.
Speaker 2: So you start with one quark you pull, and you
Speaker 2: end up with two. You can never isolate one. The
Speaker 2: vacuum is the prison guard of matter.
Speaker 3: It is the glue that binds the nucleus together. Without
Speaker 3: this specific, weird anti screening behavior of the vacuum, protons
Speaker 3: and neutrons wouldn't hold together. Atoms wouldn't exist, we wouldn't exist.
Speaker 2: So we've covered how the vacuum works now. It's screens electrons,
Speaker 2: it brind's quarks, It pushes plates around and makes black
Speaker 2: holes evaporate. But what about the beginning, the ultimate origin story,
Speaker 2: the Big Bank. There's a theory that says the entire
Speaker 2: universe itself is just a vacuum fluctuation that got well,
Speaker 2: a little out of hand.
Speaker 3: That's essentially the core idea behind inflationary cosmology.
Speaker 2: Can you explain that? How do you get everything from nothing?
Speaker 3: In the very first fraction of a second, we think
Speaker 3: the universe underwent a period of hyper accelerated expansion called inflation.
Speaker 3: But what drove it? The theory says it was driven
Speaker 3: by the energy of a quantum field, the inflint and field.
Speaker 3: It was a very high energy vacuum state.
Speaker 2: Okay, a supercharged verse of the vacuum we have today.
Speaker 3: Exactly Now, remember those tiny quantum jitters we talked about
Speaker 3: at the very start, the unavoidable fuzziness from the uncertainty principle.
Speaker 2: The microscopic fluctuations.
Speaker 3: During inflation, the fabric of space itself expanded so incredibly fast,
Speaker 3: faster than the speed of light, that those tiny microscopic
Speaker 3: subatomic jitters got stretched. They were physically stretched from a
Speaker 3: size smaller than a proton to the size of a galaxy.
Speaker 2: Whoa so a quantum blip a momentary energy fluctuation became
Speaker 2: a galaxy.
Speaker 3: It became the seed of a galaxy. Those fluctuations stretched
Speaker 3: across the cosmos created tiny differences in density across the
Speaker 3: early universe. Some spots were a little denser, some a
Speaker 3: little emptier, all because of a quantum roll.
Speaker 2: Of the dice, and gravity took over from there.
Speaker 3: Exactly over millions of years, the slightly denser spots pulled
Speaker 3: in more matter, eventually collapsing to form the first stars, galaxies,
Speaker 3: and the great cosmic web. The slightly emptier spots became
Speaker 3: the great voids between the galaxy clusters.
Speaker 2: So if I look at a map of the large
Speaker 2: scale structure of the universe, that web of galaxies, what
Speaker 2: I'm really looking at is a blown up, fossilized picture
Speaker 2: of the quantum vacuum from thirteen point eight billion years ago.
Speaker 3: You are and we have incredible proof of this. We
Speaker 3: can look at the cosmic microwave background radiation, the baby
Speaker 3: picture of the universe. It shows tiny temperature fluctuations. The
Speaker 3: specific pattern of those hot and cold spots on the
Speaker 3: sky matches the mathematical predictions of quantum vacuum fluctuations perfectly.
Speaker 2: That is, man that is heavy. We are literally made
Speaker 2: of frozen quantum noise.
Speaker 3: We are If the early vacuum had been truly still
Speaker 3: truly empty in the classical sense, the universe would be
Speaker 3: a smooth, featureless, boring soup of particles, no stars, no planets,
Speaker 3: no us. The fundamental instability of nothing is the only
Speaker 3: reason that something exists at all.
Speaker 2: There's also something called the Shwinger effect, right, which is
Speaker 2: about like ripping matter directly out of the void here
Speaker 2: and now.
Speaker 3: Yes, this connects back to that idea of creating something
Speaker 3: from nothing. The physicist Swinger predicted that if you could
Speaker 3: create an electric field that is strong enough, and I
Speaker 3: mean truly ridiculously massive, like ten eighteen volts per meter.
Speaker 2: Which is a lot, a lot.
Speaker 3: More than we can currently make. But if you could,
Speaker 3: the field would be so strong it would literally pull
Speaker 3: on the virtual electron positron pairs in the vacuum, rip
Speaker 3: them apart before they can annihilate, and make them real.
Speaker 2: Just by applying a strong enough field to empty space.
Speaker 3: Yes, you provide enough energy to the vacuum with your
Speaker 3: field to pay the mass debt, and pop, real matter
Speaker 3: appears where there was none before. We haven't fully achieved
Speaker 3: this in a lab yet, but some of the world's
Speaker 3: most high powered lasers are getting very, very close to
Speaker 3: that limit.
Speaker 2: It's the ultimate alchemy, making matter from empty space.
Speaker 3: It reinforces the modern idea that matter isn't really a
Speaker 3: separate thing in the vacuum. Matter is just an excitation
Speaker 3: of the vacuum. It's a persistent wave on that quantum motion.
Speaker 3: You can't have the waves without the water.
Speaker 2: This whole conversation, it really shifts the philosophical ground, doesn't it.
Speaker 3: It absolutely does.
Speaker 2: We usually think of creation as needing a builder, an
Speaker 2: external agent, someone to arrange the bricks and mortar. But
Speaker 2: this suggests that the bricks just appear spontaneously because the
Speaker 2: empty space refuses to be quiet.
Speaker 3: Exactly. Nothing is unstable in modern physics. You don't necessarily
Speaker 3: need a miracle to get a universe. You just need
Speaker 3: a quantum vacuum. In time, the void is naturally fundamentally creative.
Speaker 2: It's beautiful in a way. The universe breathes, and.
Speaker 3: There's one final frontier, a real bleeding edge idea. We
Speaker 3: should touch on the idea that space and time themselves
Speaker 3: might not be fundamental.
Speaker 2: What could be more fundamental than space and time the vacuum.
Speaker 3: Some modern theories, ideas from string theory and quantum gravity,
Speaker 3: suggest that space time is emergent, that the connections, the
Speaker 3: quantum entanglement between different regions of the quantum vacuum are
Speaker 3: what actually stitch the fabric of space together.
Speaker 2: So if you could somehow turn off the entanglement between
Speaker 2: the fluctuations, space.
Speaker 3: Would fall apart. The very concept of distance might lose
Speaker 3: its meaning.
Speaker 2: That is a lot to process it is.
Speaker 3: We are still learning. We still have the vacuum catastrophe
Speaker 3: to solve, We have the connection between the vacuum and
Speaker 3: gravity to figure out. Yeah, but one thing is absolutely settled.
Speaker 3: The box is not empty.
Speaker 2: The box is alive.
Speaker 3: The void is alive.
Speaker 2: So the next time you look up at that night
Speaker 2: sky and you see that profound darkness between the stars,
Speaker 2: don't think of it as nothing. Think of it as
Speaker 2: a seething, boiling ocean of potential, buzzing with invisible energy,
Speaker 2: creating and destroying particles every billionth of a second, holding
Speaker 2: the core of your atoms together and pushing the galaxies apart.
Speaker 3: It's the fullest, busiest place in the universe.
Speaker 2: And here's the thought to leave you with If space
Speaker 2: time itself truly does emerge from the web of entanglement
Speaker 2: of the vacuum, as these new theories suggest, are space
Speaker 2: and time dissilusions? Are they just a useful story our
Speaker 2: minds tell, a story created by the incessant crackling buzz
Speaker 2: of the void. Are we just surfing on the noise?
Speaker 3: That is the question that keeps physicists up at night.
Speaker 2: Thanks for this fascinating journey, pleasure as always,