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<v Speaker 1>Welcome to the quart Side Quantum Physics Podcast, an exploration

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<v Speaker 1>of the fundamental structure of reality, where quantum laws govern matter, energy,

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<v Speaker 1>and information. Here, uncertainty is a feature, not a flaw,

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<v Speaker 1>and understanding begins at the smallest scales.

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<v Speaker 2>Imagine you have a highly secure, completely indestructible cosmic vault.

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<v Speaker 3>Like a safe of just absolute perfection.

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<v Speaker 2>Yeah, exactly, a safe so perfect that the laws of

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<v Speaker 2>physics themselves basically guarantee nothing can ever break into it. Yeah,

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<v Speaker 2>and nothing placed inside can ever be retrieved.

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<v Speaker 3>Right, It's a one way trip, exactly.

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<v Speaker 2>Now, Suppose you take the world's most detailed encyclopedia, like

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<v Speaker 2>a massive compilation of every historical event, every scientific discovery,

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<v Speaker 2>every nuance of human thought, and you lock it inside

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<v Speaker 2>this vault.

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<v Speaker 3>It's locked away for good, right.

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<v Speaker 2>And for decades the absolute greatest minds in physics promised

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<v Speaker 2>us that the book was safe, hidden, sure, completely inaccessible

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<v Speaker 2>to us, obviously, but fundamentally preserved in the fabric of.

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<v Speaker 3>Reality, which is comforting. You know, the idea that the

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<v Speaker 3>universe keeps its receipts.

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<v Speaker 2>Yeah, But today we're going to look at the terrifying

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<v Speaker 2>mathematical proof the vault doesn't just permanently lock it Actually

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<v Speaker 2>it slowly and agonizingly dissolves into just random futureless scatting,

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<v Speaker 2>which is a huge problem, a massive problem, because in

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<v Speaker 2>that process it completely erases that book from the history

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<v Speaker 2>of the universe.

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<v Speaker 3>It's a scenario that genuinely kept physicists awake at night

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<v Speaker 3>for the better part of forty years.

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<v Speaker 2>Wow, really forty years.

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<v Speaker 3>Oh absolutely, because if that encyclopedia is truly e raised,

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<v Speaker 3>I mean, if the data of the universe can actually

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<v Speaker 3>be permanently deleted, then the absolute bedrock of modern science

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<v Speaker 3>just crumbles.

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<v Speaker 2>It breaks everything we.

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<v Speaker 3>Know it does. We are talking about the ultimate clash

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<v Speaker 3>of physics titans here, the most profound fault line in

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<v Speaker 3>our entire understanding of reality.

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<v Speaker 2>So, for you listening, we're dealing with two undisputed heavyweights

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<v Speaker 2>in physics here, and they are both up until this point,

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<v Speaker 2>completely undefeated in their own arenas. On one side, we

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<v Speaker 2>have general relativity.

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<v Speaker 3>Umber Einstein's absolute masterpiece, right.

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<v Speaker 2>The framework that dictates gravity, planetary orbits, colliding galaxies, all

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<v Speaker 2>the massive large skull structure of the cosmos. General relativity

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<v Speaker 2>treats space and time as this single woven fabric a.

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<v Speaker 3>Smooth, continuous geometric manifold.

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<v Speaker 2>Yeah, exactly, bends and warps under the weight of stus

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<v Speaker 2>and planets. It is a world of smooth curves, highly

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<v Speaker 2>predictable paths, and just absolute.

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<v Speaker 3>Determinism and then ruling. The completely opposite end of the

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<v Speaker 3>cosmic scale is quantum mechanics.

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<v Speaker 2>The realm of the tiny right.

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<v Speaker 3>The framework of atoms, subatomic particles, the microscopic world. And

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<v Speaker 3>unlike the smooth, predictable curves of relativity, quantum mechanics is well,

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<v Speaker 3>it's fundamentally discrete, and it's inherently probabilistic.

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<v Speaker 2>It's messy, very messy.

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<v Speaker 3>It operates on wave functions, jittery, uncertainty, discrete packets of

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<v Speaker 3>energy called quanta, and most importantly for what we're talking

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<v Speaker 3>about today, it operates on information.

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<v Speaker 2>And the thing is, both of these theories are phenomenally successful, right.

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<v Speaker 3>Oh, they are the most rigorously tested mathematical frameworks in

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<v Speaker 3>human history hands down.

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<v Speaker 2>Like we literally use general relativity to synchronize the GPS

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<v Speaker 2>satellites orbiting the Earth. We have to adjust for the

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<v Speaker 2>fact that time moves slightly faster out there than it

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<v Speaker 2>does down here on the surface.

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<v Speaker 3>Yeah, without relativity, Google maps would be useless in a

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<v Speaker 3>day exactly.

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<v Speaker 2>And we use quantum mechanics to design microchips, lasers, MRI machines.

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<v Speaker 2>As long as they stay in their respective lanes, everything

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<v Speaker 2>works beautifully.

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<v Speaker 3>The trouble begins when you find a phenomenon in the

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<v Speaker 3>universe that refuses to respect those boundaries.

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<v Speaker 2>Right, something that is simultaneously incredibly massive, so it requires

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<v Speaker 2>general relativity and incredibly tiny, which requires quantum mechanics.

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<v Speaker 3>And when you force these two frameworks to sit at

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<v Speaker 3>the exact same table, they don't just politely disagree with

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<v Speaker 3>each other.

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<v Speaker 2>No, they start throwing punches, they.

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<v Speaker 3>Produce catastrophic mathematical infinities. They just fundamentally contradict each other.

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<v Speaker 2>And the ultimate battleground where this entire contradiction plays out

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<v Speaker 2>is inside a black hole. Because when a star collapses

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<v Speaker 2>into a singularity, you have the mass of multiple suns

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<v Speaker 2>crushed down into this microscopic, quantum sized speck.

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<v Speaker 3>So you need both rule books.

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<v Speaker 2>You need both, but when you try to apply them

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<v Speaker 2>simultaneously to figure out what happens to the information that

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<v Speaker 2>falls inside, they make completely completely incompatible claims.

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<v Speaker 3>One says the data is hidden forever. The other says,

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<v Speaker 3>the data is deleted entirely, which.

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<v Speaker 2>Birth the black hole information paradox.

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<v Speaker 3>And if we cannot reconcile this contradiction, it basically means

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<v Speaker 3>our fundamental grasp of physical reality is deeply, deeply flawed.

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<v Speaker 2>Okay, let's unpack this because we need to lay down

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<v Speaker 2>the basic of what a black hole actually is before

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<v Speaker 2>we get into the mind bending qu some stuff.

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<v Speaker 3>That's a good idea. To really grasp the horror of

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<v Speaker 3>the paradox, we have to start with the classical picture.

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<v Speaker 3>We need to clearly define the trap before we spring it.

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<v Speaker 2>So, under the classical rules of Einstein's general relativity, a

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<v Speaker 2>black hole is born from this catastrophic stellar death. You

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<v Speaker 2>have a massive star exponentially larger than our own sun,

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<v Speaker 2>right and for millions of years, this star maintains this

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<v Speaker 2>very delicate, very violent equilibrium.

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<v Speaker 3>It's basically a constant tug of war. The sheer, unfathomable

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<v Speaker 3>mass of the star creates a gravitational field that is

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<v Speaker 3>perpetually trying to crush the star inward. It wants to collapse,

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<v Speaker 3>It always wants to collapse. But at the exact same time,

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<v Speaker 3>the core of the star is this raging nuclear furnace

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<v Speaker 3>doing nuclear fusion exactly, the process of smashing lighter elements

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<v Speaker 3>together to forge heavier ones, And that fusion releases a

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<v Speaker 3>colossal amount of energy that pushes outwards.

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<v Speaker 2>So gravity pulls in, fusion pushes out, and the star.

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<v Speaker 3>Holds its shape until the fuel finally runs out.

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<v Speaker 2>Right.

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<v Speaker 3>When the star exhausts its nuclear material, that fusion engine

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<v Speaker 3>just sputters and dies. The outward pressure vanishes in an instant.

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<v Speaker 2>And gravity just wins.

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<v Speaker 3>Gravity, which never sleeps and never weakens, suddenly has literally

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<v Speaker 3>zero opposition. The entire mass of the star goes into

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<v Speaker 3>a catastrophic free fall, collapsing inward on itself.

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<v Speaker 2>And if the star exceeds a specific mass threshold I

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<v Speaker 2>think it's called the Tolman Oppenheimer Volkov limit.

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<v Speaker 3>Yeah, the TV limit. If it's heavier than that, there

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<v Speaker 3>is no physical force known to science that can halt

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<v Speaker 3>the collapse.

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<v Speaker 2>Wow.

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<v Speaker 3>Not even the repulsion of atoms, not the repulsion of electrons,

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<v Speaker 3>not the strong nuclear force between neutrons. Nothing. The matter

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<v Speaker 3>is crushed into a point of such extreme density that

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<v Speaker 3>the local fabric of space time is warped to an

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<v Speaker 3>infinite degree.

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<v Speaker 2>It basically creates a well in space time so deep,

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<v Speaker 2>so precipitous that a region of the universe becomes completely

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<v Speaker 2>causally disconnected from the rest of the cosmos.

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<v Speaker 3>Causally disconnected.

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<v Speaker 2>That's the key, meaning the chain of cause and effect

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<v Speaker 2>is just cleanly severed. Nothing that occurs inside that region

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<v Speaker 2>can ever have an effect on anything outside of.

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<v Speaker 3>It, right, And the boundary of that causally disconnected region

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<v Speaker 3>is what we call the event horizon. But it is

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<v Speaker 3>so vital to understand that the event horizon is not

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<v Speaker 3>a physical object.

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<v Speaker 2>It's not a wall.

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<v Speaker 3>No, it's not a membrane or a surface you could

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<v Speaker 3>actually touch. It is strictly a mathematical.

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<v Speaker 2>Threshold, the ultimate point of no return.

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<v Speaker 3>Exactly mathematically, it is the exact spherical boundary where the

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<v Speaker 3>escape velocity required to overcome the black hole's gravitational pull

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<v Speaker 3>equals the speed of light.

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<v Speaker 2>And since the speed of light is the absolute cosmic

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<v Speaker 2>speed limit, anything that slips past this boundary would literally

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<v Speaker 2>need to travel faster than light to get back.

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<v Speaker 3>Out, which is impossible under relativity.

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<v Speaker 2>So if a photon of light was traveling straight outward,

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<v Speaker 2>directly away from the singularity, moving at one hundred and

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<v Speaker 2>eighty six thousand miles per second. Because the space itself

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<v Speaker 2>is flowing inward faster than the speed of light, that

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<v Speaker 2>photon is actually dragged backward into this center.

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<v Speaker 3>It's like swimming against a river that's moving faster than

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<v Speaker 3>you can possibly swim. Once you cross the event horizon,

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<v Speaker 3>all paths through spacetime lead inevitably to the singularity. The

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<v Speaker 3>future only points inward.

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<v Speaker 2>Which means anything that falls in is completely excised from

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<v Speaker 2>the observable universe. And this classical understanding led the physicist

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<v Speaker 2>John Wheeler to coin a very famous phrase. Right He said,

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<v Speaker 2>black holes.

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<v Speaker 3>Have no hair, the no hair theorem.

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<v Speaker 2>I really want to spend a minute on this because

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<v Speaker 2>hair is such a bizarre metaphor for physicists to use.

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<v Speaker 2>What are we actually talking about when we say a

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<v Speaker 2>black hole is bald?

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<v Speaker 3>Well? In physics jargon, hair just refers to any complex details,

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<v Speaker 3>specific traits, or distinguishing information about the matter that originally

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<v Speaker 3>formed the object.

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<v Speaker 2>So a normal star has hair, A star.

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<v Speaker 3>Has a ton of hair. It has a specific chemical composition,

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<v Speaker 3>a complex magnetic field, topography, temperature variations, convection currents, sunspots.

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<v Speaker 3>It is incredibly complex.

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<v Speaker 2>The Wheeler and his colleagues proved mathematically that once a

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<v Speaker 2>star collapses into a black hole and the space time

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<v Speaker 2>kind of settles down, almost all of that complexity just

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<v Speaker 2>vanishes from the observable universe.

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<v Speaker 3>Every bit of it. The entire black hole can be

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<v Speaker 3>completely exhaustively described by just three macroscopic numbers, just three mass,

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<v Speaker 3>electric charge, and angular momentum, which is just the rate

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<v Speaker 3>of its spin. That is the entire identity of a

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<v Speaker 3>black hole. Three numbers.

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<v Speaker 2>Okay, to make this incredibly concrete for the listener, let's

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<v Speaker 2>go back to the encyclopedia we threw into the vault.

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<v Speaker 2>But let's add something completely different to the mix.

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<v Speaker 3>Okay, let's here it.

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<v Speaker 2>Let's say you throw a massive encyclopedia detailing all of

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<v Speaker 2>human history into the black hole, and then, just for

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<v Speaker 2>the sake of comparison, you throw a standard for slice

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<v Speaker 2>Kischen toaster into the exact same black hole.

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<v Speaker 3>Two systems with vastly, vastly different microscopic states.

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<v Speaker 2>Right, The encyclopedia has a specific arrangement of ink molecules

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<v Speaker 2>forming words pages made of cellulose. The toaster is composed

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<v Speaker 2>of alloys plastic heating coils they have totally distinct chemical bonds.

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<v Speaker 3>But according to the no hair theorem, the moment they

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<v Speaker 3>cross the event horizon, the universe outside is completely wiped

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<v Speaker 3>of that distinguishing data.

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<v Speaker 2>The black hole does not retain the toasterness of the

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<v Speaker 2>toaster or the linguistic data of the encyclopedia.

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<v Speaker 3>Not at all. The black hole just increments its mass slightly.

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<v Speaker 3>Maybe the angular momentum shifts a tiny fraction of a degree,

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<v Speaker 3>depending on the angle the objects fell in at.

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<v Speaker 2>But if I am standing outside looking at the black hole,

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<v Speaker 2>I cannot run any test, measure any feel, or perform

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<v Speaker 2>any observation that will tell me whether the black hole

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<v Speaker 2>just consumed an encyclopedia or a kitchen appliance.

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<v Speaker 3>You'd have absolutely no idea. All the microscopic complexity, the

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<v Speaker 3>exact arrangement of atoms that define the object is swallowed,

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<v Speaker 3>leaving no signature on the gravitational field outside. The black

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<v Speaker 3>hole acts as the ultimate cosmic shredder of identity.

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<v Speaker 2>Now here's where it gets crucial for the paradox. Why

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<v Speaker 2>were physicists in the nineteen six these and seventies perfectly

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<v Speaker 2>content with this? Why wasn't the no hair theorem considered

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<v Speaker 2>an immediate crisis for the laws of physics.

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<v Speaker 3>Because classical relativity offers a very comforting out a loophole. Exactly,

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<v Speaker 3>the information wasn't viewed as destroyed. It was simply inaccessible.

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<v Speaker 3>The assumption was that the toasterness and the words in

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<v Speaker 3>the encyclopedia still exist in some form, crushed down into

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<v Speaker 3>the singularity or floating around in the interior space.

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<v Speaker 2>It's exactly like the locked vault analogy. You can't read

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<v Speaker 2>the book through the fixed steel walls, but you have

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<v Speaker 2>the comforting mathematical certainty that the book remains physically present inside.

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<v Speaker 3>Right, the accounting of the universe is still balanced. The

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<v Speaker 3>data is hidden, sure, but the universe hasn't suffered amnesia.

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<v Speaker 3>The rules of determinism still hold because the past state

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<v Speaker 3>of the universe is safely stored behind the event horizon.

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<v Speaker 2>And that was the consensus. Black holes were the universe's

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<v Speaker 2>ultimate safety deposit boxes.

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<v Speaker 3>But that elegant, comforting picture relied entirely on classical physics.

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<v Speaker 3>It treated space time as this smooth, empty void, and

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<v Speaker 3>as physics progressed, it became completely undeniable that this was

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<v Speaker 3>an incomplete description of.

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<v Speaker 2>Reality, because it completely ignored the quantum realm. Yes, and

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<v Speaker 2>when physicists finally started applying the rules of quantum mechanics

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<v Speaker 2>to the extremely warped space time surrounding the event horizon,

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<v Speaker 2>the narrative just violently shifted. The vault wasn't static anymore.

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<v Speaker 3>This is the quantum wrench in the machinery. In nineteen

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<v Speaker 3>seventy four, Stephen Hawking applied a framework called quantum field

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<v Speaker 3>theory in curved space time to the edge of the

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<v Speaker 3>black hole, and the math yielded a monumental, deeply counterintuitive.

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<v Speaker 2>Discovery that black holes are not entirely bladed.

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<v Speaker 3>Exactly, they glow. They emit a very very faint radiation

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<v Speaker 3>Hawking radiation.

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<v Speaker 2>Now, to understand how a trap from which not even

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<v Speaker 2>light can escape manages to somehow radiate particles, we have

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<v Speaker 2>to dramatically alter our view of what empty space actually is.

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<v Speaker 3>Right, because classical relativity treats a vacuum as a pure void,

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<v Speaker 3>just an empty stage with no actors on it.

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<v Speaker 2>Qantum field theory tells us that a true pure void

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<v Speaker 2>does not exist anywhere the entire universe is permeated by

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<v Speaker 2>these quantum fields, like an electromagnetic field, an electron field,

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<v Speaker 2>a quark field.

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<v Speaker 3>And these fields are never perfectly still. Due to the

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<v Speaker 3>Heisenberd uncertainty principle. You can never have a field with

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<v Speaker 3>exactly zero energy for a precise amount of time.

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<v Speaker 2>The universe inherently jitters.

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<v Speaker 3>It does. Empty space is basically boiling. It is a

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<v Speaker 3>frothing sea of quantum fluctuations. Energy is constantly transforming into

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<v Speaker 3>pairs of particles. A particle and its corresponding antiparticle.

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<v Speaker 2>They just spontaneously pop into existence.

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<v Speaker 3>Yet they just pop in borrowing a tiny fraction of

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<v Speaker 3>energy from the vacuus.

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<v Speaker 2>It's like nature's accounting system constantly taking out micro loans

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<v Speaker 2>of energy.

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<v Speaker 3>That's a great way to put it, a microlan that

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<v Speaker 3>must be paidback almost instantly. The particle and antiparticle exists

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<v Speaker 3>for a fleeting, unimaginably brief fraction of a second before

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<v Speaker 3>they collide, annihilate each other, and return the energy to

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<v Speaker 3>the vacuum. And this happens everywhere, everywhere, constantly, in the

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<v Speaker 3>room you were sitting in right now, in the deepest

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<v Speaker 3>voids between distant galaxies.

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<v Speaker 2>But it's a closed loop. It happens so fast that

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<v Speaker 2>on a macroscopic scale, we just perceive the space is empty.

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<v Speaker 3>Usually yes, But Hacking asked a really brilliant theoretical question.

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<v Speaker 3>What happens if this spontaneous particle anti particle pair creation

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<v Speaker 3>occurs right on the absolute razor's edge of a black

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<v Speaker 3>hole's event horizon.

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<v Speaker 2>Right on that boundary where space time is flowing inward

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<v Speaker 2>at the speed of light.

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<v Speaker 3>Exactly under these extreme conditions, the massive gravitational tidle forces

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<v Speaker 3>of the black hole can actually interact with this microscopic

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<v Speaker 3>quantum event. Imagine the pair pops into existence.

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<v Speaker 2>Okay, I'm picturing it, but before they.

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<v Speaker 3>Have the chance to magnetically attract and annihilate each other,

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<v Speaker 3>the tidle forces just rip them apart. One particle happens

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<v Speaker 3>to form just inside the mathematical boundary of the event horizon,

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<v Speaker 3>the other forms just outside.

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<v Speaker 2>Oh wow, So the particle inside is doomed. It is

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<v Speaker 2>instantly swept inward towards the singularity.

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<v Speaker 3>But the particle on the outside finds itself free of

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<v Speaker 3>its partner. It has positive energy, and if the trajectory

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<v Speaker 3>is just right, it has just enough velocity to escape

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<v Speaker 3>the black hole's gravitational pull and fly out into deep space.

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<v Speaker 2>So to a distant observer looking at the black hole,

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<v Speaker 2>it appears as though the black hole just emitted a particle.

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<v Speaker 2>It is radiating.

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<v Speaker 3>It is radiating.

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<v Speaker 2>But wait a minute. We established that the universe demands

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<v Speaker 2>its accounting books balance perfectly. Energy must be conserved. You

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<v Speaker 2>can't just spawn a real particle that flies off into

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<v Speaker 2>space and completely ignore the micro loan of energy that

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<v Speaker 2>created it.

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<v Speaker 3>No, you absolutely cannot. The universe does not tolerate unpaid

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<v Speaker 3>energy debts. The escaping particle carries positive energy away with it. Therefore,

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<v Speaker 3>to ensure the total energy of the system remains perfectly balanced,

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<v Speaker 3>the math dictates that the particle which fell into the

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<v Speaker 3>black hole must carry negative energy.

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<v Speaker 2>Negative energy, which means when it falls into the math

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<v Speaker 2>of the black hole, it doesn't add to it, it

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<v Speaker 2>actually subtracts from it.

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<v Speaker 3>Yes, the black hole absorbs a negative energy particle, meaning

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<v Speaker 3>the black hole's overall mass decreases by a microscopic fraction.

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<v Speaker 2>The black hole is evaporating.

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<v Speaker 3>Very very slowly. I mean for a supermassive black hole.

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<v Speaker 3>The temperature of this radiation is infinitesimally small, far colder

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<v Speaker 3>than the ambient temperature of the cosmic microwave background.

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<v Speaker 2>So right now, large black holes are actually absorbing more

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<v Speaker 2>background heat than they emit exactly.

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<v Speaker 3>But eventually, trillions of years from now, when the universe

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<v Speaker 3>expands and cools to near absolute zero, the black holes

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<v Speaker 3>will become the hottest things around.

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<v Speaker 2>And then the tide turns.

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<v Speaker 3>They will begin to steadily lose mass, and as they shrink,

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<v Speaker 3>the tidal forces at the horizon grow more intense. The

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<v Speaker 3>temperature goes up, the radiation accelerates, until eventually the black

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<v Speaker 3>hole evaporates entirely in a final brilliant flash of high energy.

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<v Speaker 2>Particles hoof gone. The vault completely does into thin air completely,

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00:17:01.519 --> 00:17:03.840
<v Speaker 2>and this brings us right to the precipice of the crisis,

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00:17:04.160 --> 00:17:06.559
<v Speaker 2>because if the vault vanishes, we are forced to ask

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<v Speaker 2>a very uncomfortable question, what happened to our encyclopedia? We

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00:17:10.680 --> 00:17:12.759
<v Speaker 2>threw the book in, the black hole swallowed it. The

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00:17:12.759 --> 00:17:15.960
<v Speaker 2>black hole radiated particles for a trillion years, and then

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<v Speaker 2>the black hole ceased to exist.

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<v Speaker 3>Where did the data go?

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<v Speaker 2>Well? The natural assumption would be that as the black

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<v Speaker 2>hole evaperates, it slowly spits the data back out into

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<v Speaker 2>the universe, encoded in the Hawking radiation.

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<v Speaker 3>That makes intuitive sense. The vault dissolves, but the contents

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<v Speaker 3>spill out into the yard.

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<v Speaker 2>But Hawking's calculations revealed a fatal flaw in that assumption.

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<v Speaker 3>Didn't they They did. When he ran the math to

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00:17:39.119 --> 00:17:42.920
<v Speaker 3>determine the exact properties of the staping radiation, he discovered

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<v Speaker 3>that the radiation is perfectly thermal.

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<v Speaker 2>Perfectly thermal, meaning it's essentially just random heat.

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<v Speaker 3>It is entirely featureless. The spectrum of the radiation depends

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00:17:53.000 --> 00:17:56.759
<v Speaker 3>solely on the black hole's mass, charge, and spin. It

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<v Speaker 3>carries absolutely zero microscopic information about the specific matter that

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<v Speaker 3>fell in wait.

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<v Speaker 2>Really, so the radiation emitted by a black hole that

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<v Speaker 2>formed from a collapse star is mathematically indistinguishable from the

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<v Speaker 2>radiation emitted by a black hole that formed from a

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<v Speaker 2>collapsing sphere of pure encyclopedias indistinguishable.

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<v Speaker 3>Every photon, every particle of Hawking radiation that escapes is

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<v Speaker 3>essentially randomized. It has absolutely no memory of the material

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<v Speaker 3>that originally collapsed.

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00:18:23.440 --> 00:18:26.559
<v Speaker 2>So if you were to collect every single particle of

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<v Speaker 2>Hawking radiation emitted over the entire trillion year lifespan of

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<v Speaker 2>the black hole, you would just have a massive chaotic

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00:18:33.519 --> 00:18:35.160
<v Speaker 2>cloud of thermal noise.

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00:18:35.680 --> 00:18:38.839
<v Speaker 3>You could never put the encyclopedia back together. The information

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<v Speaker 3>isn't just hidden inside the event horizon anymore, because the

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00:18:42.079 --> 00:18:46.799
<v Speaker 3>event horizon is gone. The information is truly fundamentally deleted

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<v Speaker 3>from the universe.

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<v Speaker 2>And that conclusion sent a massive shockwave through the foundations

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<v Speaker 2>of physics because the permanent deletion of information is a direct,

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<v Speaker 2>undeniable violation of the most sapred rule. In quantum mechanics,

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<v Speaker 2>principle of unitarity unitarity.

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<v Speaker 3>Yes, we need to define this carefully because it is

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<v Speaker 3>the absolute lynchpin of the entire paradise.

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<v Speaker 2>Right, why does quantum mechanics care so deeply about preserving information?

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00:19:11.000 --> 00:19:14.160
<v Speaker 3>Well. In quantum mechanics, unitarity dictates that the evolution of

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<v Speaker 3>any closed physical system is governed by a unitary operator. Mathematically,

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<v Speaker 3>a unitary operator is a transformation that preserves the total

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<v Speaker 3>probability of all possible outcomes at exactly one hundred percent.

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<v Speaker 2>Okay, but conceptually a guarantee something much more profound, right, yeah,

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<v Speaker 2>absolute reversibility exactly.

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<v Speaker 3>Unitarity implies that every unique quantum state in the past

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<v Speaker 3>evolves into a unique, distinct quantum state in the future.

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00:19:39.400 --> 00:19:42.440
<v Speaker 3>And critically, every quantum state in the present can be

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<v Speaker 3>traced backward to one and only one specific state in

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<v Speaker 3>the past.

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<v Speaker 2>So the flow of time in a quantum system is

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<v Speaker 2>a two way street. Information must be strictly preserved, no

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<v Speaker 2>matter how scrambled things appear.

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00:19:54.799 --> 00:19:58.200
<v Speaker 3>Yes, let's use a classical analogy that mimics this quantum rule.

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00:19:58.279 --> 00:20:01.079
<v Speaker 3>Let's look at a process that seems to destroy information

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00:20:01.279 --> 00:20:02.400
<v Speaker 3>but actually doesn't.

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<v Speaker 2>Okay, let's say I take our encyclopedia and instead of

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<v Speaker 2>throwing it into a black hole, I throw it into

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00:20:07.279 --> 00:20:08.480
<v Speaker 2>a roaring fire, a.

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00:20:08.480 --> 00:20:11.119
<v Speaker 3>Highly destructive process from a human perspective.

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00:20:11.240 --> 00:20:13.920
<v Speaker 2>Right, I watch the pages burn. The book turns into

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00:20:13.960 --> 00:20:16.359
<v Speaker 2>a pile of ash, a bloom of smoke, and a

400
00:20:16.359 --> 00:20:18.880
<v Speaker 2>burst of heat. To my human eyes, the words are gone.

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00:20:19.279 --> 00:20:23.160
<v Speaker 2>The linguistic information of the encyclopedia seems utterly destroyed.

402
00:20:22.759 --> 00:20:26.000
<v Speaker 3>But to a physicist it is merely scrambled. It has

403
00:20:26.079 --> 00:20:29.240
<v Speaker 3>undergone a vast increase in entropy, but it has not

404
00:20:29.440 --> 00:20:30.640
<v Speaker 3>violated unitarity.

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00:20:30.960 --> 00:20:36.319
<v Speaker 2>Because if you possessed a theoretical magical supercomputer, one capable

406
00:20:36.319 --> 00:20:40.559
<v Speaker 2>of tracking the exact quantum state, trajectory and momentum of

407
00:20:40.720 --> 00:20:44.640
<v Speaker 2>every single photon of light emitted by the fire, every

408
00:20:44.720 --> 00:20:48.039
<v Speaker 2>single microscopic molecule of smoke wafting into the.

409
00:20:48.000 --> 00:20:51.240
<v Speaker 3>Atmosphere, every subtle change in the kinetic energy of the

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00:20:51.279 --> 00:20:52.640
<v Speaker 3>surrounding air molecules.

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00:20:52.720 --> 00:20:56.240
<v Speaker 2>Right, I could theoretically feed all that data into the supercomputer,

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00:20:56.599 --> 00:21:00.000
<v Speaker 2>apply the laws of physics, and run the simulation in reverse.

413
00:21:00.039 --> 00:21:03.200
<v Speaker 3>And the math would perfectly reassemble the encyclopedia. The smoke

414
00:21:03.240 --> 00:21:05.880
<v Speaker 3>would draw back together, the heat would converge, the ash

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00:21:05.880 --> 00:21:09.279
<v Speaker 3>would form pages, and the ink would resolve into specific words.

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00:21:09.599 --> 00:21:11.920
<v Speaker 2>The information about what was written on page forty two

417
00:21:12.119 --> 00:21:15.720
<v Speaker 2>was never actually annihilated, It was just redistributed exactly.

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00:21:15.880 --> 00:21:20.279
<v Speaker 3>It was converted into incredibly complex microscopic correlations between the smoke,

419
00:21:20.559 --> 00:21:24.039
<v Speaker 3>the ash, and the heat. The universe still possesses the data.

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00:21:24.559 --> 00:21:28.079
<v Speaker 2>Unitarity guarantees that nature never loses track of the details,

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00:21:28.319 --> 00:21:30.920
<v Speaker 2>even in utter chaos. The bookkeeping is immaculate.

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00:21:31.160 --> 00:21:34.079
<v Speaker 3>But Hawking's math claimed that a black hole doesn't act

423
00:21:34.160 --> 00:21:37.200
<v Speaker 3>like a fire. Hawking claimed a black hole acts as

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00:21:37.200 --> 00:21:41.559
<v Speaker 3>an absolute eraser. It takes the encyclopedia, burns it, and

425
00:21:41.599 --> 00:21:44.519
<v Speaker 3>then permanently deletes the smoke, the ash, and the heat

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00:21:44.559 --> 00:21:45.799
<v Speaker 3>from reality entirely.

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00:21:46.400 --> 00:21:50.119
<v Speaker 2>If the black hole evaporates completely and leaves behind only generic,

428
00:21:50.400 --> 00:21:56.559
<v Speaker 2>perfectly random thermal radiation. The information is irretrievably lost. It

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00:21:56.640 --> 00:21:58.960
<v Speaker 2>literally cannot be traced backward.

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00:21:58.799 --> 00:22:02.799
<v Speaker 3>And the implications of that are catastrophic. If unitarity falls,

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00:22:03.200 --> 00:22:04.519
<v Speaker 3>quantum mechanics falls with it.

432
00:22:05.039 --> 00:22:08.599
<v Speaker 2>If information can truly be destroyed, the fundamental laws of

433
00:22:08.640 --> 00:22:11.440
<v Speaker 2>physics lose their predictive and retrodictive power.

434
00:22:12.079 --> 00:22:14.400
<v Speaker 3>If we connect this to the bigger picture, it breaks

435
00:22:14.440 --> 00:22:18.359
<v Speaker 3>causality Because of two entirely different pasts, like a black

436
00:22:18.400 --> 00:22:21.440
<v Speaker 3>hole made of encyclopedias and a black hole made of toasters,

437
00:22:21.720 --> 00:22:24.599
<v Speaker 3>both evolve into the exact same future state of featureless

438
00:22:24.599 --> 00:22:26.720
<v Speaker 3>thermal radiation. Causality breaks.

439
00:22:26.839 --> 00:22:30.200
<v Speaker 2>You lose determinism entirely. If you observe the final thermal

440
00:22:30.200 --> 00:22:32.799
<v Speaker 2>cloud and you try to run the laws of physics backward,

441
00:22:33.000 --> 00:22:34.359
<v Speaker 2>the math crashes.

442
00:22:34.039 --> 00:22:36.480
<v Speaker 3>The equations wouldn't know which pass to return to.

443
00:22:36.799 --> 00:22:40.160
<v Speaker 2>The universe would have essentially randomly deleted a section of

444
00:22:40.200 --> 00:22:43.799
<v Speaker 2>its own causal history. You would have to accept that

445
00:22:43.799 --> 00:22:49.240
<v Speaker 2>physical reality is inherently lossy, constantly degrading its own fundamental resolution.

446
00:22:49.599 --> 00:22:52.480
<v Speaker 3>It's like watching a high definition movie, but every time

447
00:22:52.480 --> 00:22:56.920
<v Speaker 3>there's a scene change the video compression permanently blurs the background,

448
00:22:57.240 --> 00:23:00.640
<v Speaker 3>until eventually the entire film is just a gray square.

449
00:23:00.759 --> 00:23:02.160
<v Speaker 2>No wonder physicists panicked.

450
00:23:02.319 --> 00:23:05.799
<v Speaker 3>Oh, the panic was entirely justified. For decades, the physics

451
00:23:05.839 --> 00:23:09.880
<v Speaker 3>community was completely fractured over this. Some prominent physicists, including

452
00:23:09.960 --> 00:23:12.960
<v Speaker 3>Hawking himself, for a long time accepted the math at

453
00:23:12.960 --> 00:23:13.720
<v Speaker 3>face value.

454
00:23:13.759 --> 00:23:17.079
<v Speaker 2>They thought, well, if general relativity and quantum mechanics conflict,

455
00:23:17.440 --> 00:23:19.240
<v Speaker 2>it must be quantum mechanics.

456
00:23:18.759 --> 00:23:21.079
<v Speaker 3>That is wrong exactly. They believed we simply had to

457
00:23:21.079 --> 00:23:23.400
<v Speaker 3>bite the bullet and accept information loss.

458
00:23:23.599 --> 00:23:27.519
<v Speaker 2>But others realized that conceding unitarity was basically equivalent to

459
00:23:28.000 --> 00:23:32.519
<v Speaker 2>surrendering the entire foundation of modern physics. Physicists like Leonard

460
00:23:32.519 --> 00:23:37.359
<v Speaker 2>Suskan and Gerard Hooft vehemently rejected the idea. They literally

461
00:23:37.400 --> 00:23:40.200
<v Speaker 2>declared theoretical war on information loss.

462
00:23:40.240 --> 00:23:42.599
<v Speaker 3>To save physics, they had to prove that the Hawking

463
00:23:42.680 --> 00:23:46.279
<v Speaker 3>radiation wasn't actually perfectly thermal. They had to find a

464
00:23:46.279 --> 00:23:49.720
<v Speaker 3>way for the information to be encoded in the escaping particles,

465
00:23:49.880 --> 00:23:50.240
<v Speaker 3>and to.

466
00:23:50.200 --> 00:23:52.599
<v Speaker 2>Do that they had to look deeply into the concept

467
00:23:52.680 --> 00:23:55.759
<v Speaker 2>of entropy. Entropy, yes, usually when we talk about entropy,

468
00:23:55.839 --> 00:23:59.000
<v Speaker 2>we were talking about thermodynamics, You know the tendency of

469
00:23:59.079 --> 00:24:02.599
<v Speaker 2>systems to move from order to disorder and egg breaking,

470
00:24:02.680 --> 00:24:06.359
<v Speaker 2>ice melting. How does this connect to information in black holes?

471
00:24:06.960 --> 00:24:10.839
<v Speaker 3>Well, in physics and particularly in information theory, which is

472
00:24:10.880 --> 00:24:14.240
<v Speaker 3>a framework developed by Claud Shannon, entropy is actually a

473
00:24:14.319 --> 00:24:17.400
<v Speaker 3>direct mathematical measure of hidden information.

474
00:24:17.079 --> 00:24:18.920
<v Speaker 2>Hidden information. Can we break that down of it?

475
00:24:18.920 --> 00:24:22.160
<v Speaker 3>Sure? Think about it as a measure of microscopic ambiguity.

476
00:24:22.400 --> 00:24:26.000
<v Speaker 3>How many microscopic ways can you arrange the internal components

477
00:24:26.039 --> 00:24:29.960
<v Speaker 3>of a system without changing its outward macroscopic appearance?

478
00:24:30.079 --> 00:24:32.680
<v Speaker 2>Oh okay, So a highly ordered system, like a perfectly

479
00:24:32.759 --> 00:24:37.279
<v Speaker 2>arranged new deck of cards, has very low entropy. There's

480
00:24:37.319 --> 00:24:40.039
<v Speaker 2>only one specific sequence that looks like a perfectly ordered deck.

481
00:24:40.359 --> 00:24:43.920
<v Speaker 2>If you swap two cards, the macroscopic state obviously changes precisely.

482
00:24:44.640 --> 00:24:47.920
<v Speaker 3>But a highly disordered system like a deck of cards

483
00:24:48.000 --> 00:24:51.720
<v Speaker 3>just scattered all over the floor, has extremely high entropy.

484
00:24:52.440 --> 00:24:55.440
<v Speaker 3>There are millions of different microscopic ways the cards could

485
00:24:55.480 --> 00:24:59.319
<v Speaker 3>be scattered that all look identically messy from a macroscopic viewpoint.

486
00:24:59.319 --> 00:25:03.200
<v Speaker 2>So high entropy means a massive amount of hidden microscopic

487
00:25:03.240 --> 00:25:06.400
<v Speaker 2>information is required to specify exactly which messi state you.

488
00:25:06.359 --> 00:25:09.920
<v Speaker 3>Were looking at exactly so entropy equals data capacity, and

489
00:25:10.000 --> 00:25:13.119
<v Speaker 3>in the nineteen seventies Jacob Beckenstein realized that black holes

490
00:25:13.200 --> 00:25:15.480
<v Speaker 3>must possess an enormous amount of entropy.

491
00:25:15.640 --> 00:25:17.960
<v Speaker 2>He was driven by a simple thought experiment, wasn't he

492
00:25:17.960 --> 00:25:18.359
<v Speaker 2>he was?

493
00:25:19.079 --> 00:25:21.920
<v Speaker 3>The second law of thermodynamics states that the total entropy

494
00:25:22.000 --> 00:25:26.279
<v Speaker 3>of an isolated system must always increase. Things always get messier, right,

495
00:25:26.480 --> 00:25:30.640
<v Speaker 3>So Bekenstein asked, what happens if I take a highly entropic,

496
00:25:30.880 --> 00:25:33.559
<v Speaker 3>messy object like a box of hot gas, and drop

497
00:25:33.599 --> 00:25:34.519
<v Speaker 3>it into a black hole?

498
00:25:34.640 --> 00:25:37.400
<v Speaker 2>The gas crosses the event horizon and vanishes from the

499
00:25:37.480 --> 00:25:39.039
<v Speaker 2>observable universe, which means.

500
00:25:38.880 --> 00:25:41.480
<v Speaker 3>The total entropy of the observable universe just went down.

501
00:25:41.519 --> 00:25:42.880
<v Speaker 3>The universe got cleaner.

502
00:25:42.720 --> 00:25:45.720
<v Speaker 2>And that is a flagrant violation of the second law

503
00:25:45.759 --> 00:25:46.759
<v Speaker 2>of thermodynamics.

504
00:25:47.000 --> 00:25:49.720
<v Speaker 3>Unless the black hole itself has an internal entropy that

505
00:25:49.759 --> 00:25:53.079
<v Speaker 3>absorbs the messiness of the gas, the black hole must

506
00:25:53.160 --> 00:25:55.079
<v Speaker 3>have a hidden information capacity.

507
00:25:55.160 --> 00:25:59.599
<v Speaker 2>It has to so Beiegenstein, along with Hawking, developed a

508
00:25:59.599 --> 00:26:03.880
<v Speaker 2>formula to calculate this, the Beckenstein Hawking entropy formula, and

509
00:26:04.000 --> 00:26:06.640
<v Speaker 2>what they discovered about a black hole's data capacity is

510
00:26:07.079 --> 00:26:10.160
<v Speaker 2>arguably one of the strangest most profound facts in all

511
00:26:10.160 --> 00:26:10.720
<v Speaker 2>of physics.

512
00:26:10.799 --> 00:26:13.160
<v Speaker 3>It really is. They found that a black hole's entropy

513
00:26:13.240 --> 00:26:15.000
<v Speaker 3>is proportional to its surface.

514
00:26:14.680 --> 00:26:17.960
<v Speaker 2>Area the area of the event horizon, not its volume,

515
00:26:18.119 --> 00:26:21.000
<v Speaker 2>right not. We need to pause here and emphasize how

516
00:26:21.039 --> 00:26:26.079
<v Speaker 2>deeply unnatural this is. Every single physical object we interact

517
00:26:26.119 --> 00:26:30.000
<v Speaker 2>with scales its data capacity with volume. If I want

518
00:26:30.000 --> 00:26:32.119
<v Speaker 2>to store more files, I buy a bigger hard drive

519
00:26:32.519 --> 00:26:35.079
<v Speaker 2>with a larger physical volume of magnetic platters.

520
00:26:35.119 --> 00:26:36.960
<v Speaker 3>If you want to store more books, you build a

521
00:26:37.000 --> 00:26:40.160
<v Speaker 3>library with more cubic feet of space. The capacity of

522
00:26:40.200 --> 00:26:42.960
<v Speaker 3>a three D object is determined by its three D volume,

523
00:26:43.039 --> 00:26:43.440
<v Speaker 3>but for a.

524
00:26:43.400 --> 00:26:46.400
<v Speaker 2>Black hole, the volume is completely irrelevant. The amount of

525
00:26:46.440 --> 00:26:49.480
<v Speaker 2>microscopic information that can conceal is strictly dictated by the

526
00:26:49.799 --> 00:26:51.920
<v Speaker 2>two D surface area of the event horizon.

527
00:26:52.160 --> 00:26:56.039
<v Speaker 3>Bekenstein realized that you could mathematically tile the event horizon

528
00:26:56.160 --> 00:27:01.480
<v Speaker 3>with these tiny squares, each measuring one plankank across.

529
00:27:00.920 --> 00:27:03.440
<v Speaker 2>The smallest meaningful unit of length in the universe.

530
00:27:03.559 --> 00:27:06.960
<v Speaker 3>Yes, and each tiny plank sized square on the surface

531
00:27:07.119 --> 00:27:09.200
<v Speaker 3>holds exactly one bit of information.

532
00:27:09.599 --> 00:27:12.319
<v Speaker 2>It is honestly like discovering that the amount of water

533
00:27:12.400 --> 00:27:14.759
<v Speaker 2>a bucket can hold doesn't depend on how deep the

534
00:27:14.759 --> 00:27:17.200
<v Speaker 2>bucket is yeah, but strictly on the surface area of

535
00:27:17.200 --> 00:27:17.599
<v Speaker 2>the lid.

536
00:27:18.039 --> 00:27:21.279
<v Speaker 3>It is a profound break from our classical understanding of space.

537
00:27:21.839 --> 00:27:24.960
<v Speaker 3>But let's return to the evaporation problem because this area

538
00:27:25.039 --> 00:27:27.240
<v Speaker 3>law creates a severe mechanical tension.

539
00:27:27.440 --> 00:27:31.000
<v Speaker 2>Right as the black hole emits Hawking radiation, it loses mass.

540
00:27:31.559 --> 00:27:34.640
<v Speaker 2>As it loses mass, its gravitational pull weakens, and the

541
00:27:34.680 --> 00:27:36.319
<v Speaker 2>spherical event horizon shrinks.

542
00:27:36.400 --> 00:27:37.759
<v Speaker 3>The surface area gets smaller.

543
00:27:38.000 --> 00:27:40.759
<v Speaker 2>And if the surface area dictates the maximum data capacity,

544
00:27:41.160 --> 00:27:44.000
<v Speaker 2>a shrinking black hole is continually losing its ability to

545
00:27:44.079 --> 00:27:45.799
<v Speaker 2>hide information exactly.

546
00:27:46.200 --> 00:27:48.880
<v Speaker 3>The total entropy of the black hole is dropping, but

547
00:27:48.960 --> 00:27:52.920
<v Speaker 3>the second law thermodynamics still demands that overall entropy must increase,

548
00:27:53.160 --> 00:27:53.440
<v Speaker 3>so the.

549
00:27:53.400 --> 00:27:56.319
<v Speaker 2>Missing entropyed the hidden data must be carried away by

550
00:27:56.319 --> 00:27:59.039
<v Speaker 2>the Hawking radiation flowing out into deep space.

551
00:27:59.279 --> 00:28:03.160
<v Speaker 3>But Hawking's maths said the radiation is purely thermal. Thermal

552
00:28:03.240 --> 00:28:07.440
<v Speaker 3>radiation has high generic entropy, meaning it's highly disordered, but

553
00:28:07.519 --> 00:28:11.640
<v Speaker 3>it doesn't carry this specific structured information of the encycled tedia.

554
00:28:11.799 --> 00:28:14.799
<v Speaker 2>You've hit the exact mechanical tension of the paradox. The

555
00:28:14.839 --> 00:28:18.599
<v Speaker 2>black hole's capacity to store data is shrinking. The radiation

556
00:28:18.680 --> 00:28:21.680
<v Speaker 2>is carrying away generic messiness, but it isn't carrying away

557
00:28:21.720 --> 00:28:22.559
<v Speaker 2>the structured data.

558
00:28:22.759 --> 00:28:26.200
<v Speaker 3>That data simply has nowhere to exist. It mathematically vanishes.

559
00:28:26.400 --> 00:28:29.279
<v Speaker 2>It feels like an air tight proof of destruction. But

560
00:28:29.319 --> 00:28:32.319
<v Speaker 2>then a physicist named Don Page steps in and kind

561
00:28:32.319 --> 00:28:33.200
<v Speaker 2>of flips the script.

562
00:28:33.480 --> 00:28:36.440
<v Speaker 3>Page's intervention in nineteen ninety three was just a masterclass

563
00:28:36.440 --> 00:28:39.599
<v Speaker 3>in reverse engineering. He didn't try to find the specific

564
00:28:39.759 --> 00:28:44.319
<v Speaker 3>flaw in Hawkings's highly complex calculations. He took a macroscopic view.

565
00:28:44.799 --> 00:28:48.640
<v Speaker 2>He asked, if we assume quantum mechanics is flawless, if

566
00:28:48.680 --> 00:28:52.920
<v Speaker 2>we assume unitarity holds and information is conserved, what must

567
00:28:52.960 --> 00:28:55.000
<v Speaker 2>the radiation look like over the life span of the

568
00:28:55.000 --> 00:28:55.519
<v Speaker 2>black hole.

569
00:28:55.839 --> 00:28:58.839
<v Speaker 3>He basically assumed the universe was rational and asked what

570
00:28:58.920 --> 00:29:01.079
<v Speaker 3>the graph of the data extraction would look.

571
00:29:01.000 --> 00:29:05.640
<v Speaker 2>Like, right, and he focused on something called entanglement entropy.

572
00:29:05.680 --> 00:29:09.200
<v Speaker 2>This measures how entangled the escaping radiation is with the

573
00:29:09.240 --> 00:29:10.640
<v Speaker 2>interior of the black hole.

574
00:29:10.720 --> 00:29:11.559
<v Speaker 3>And what did he find.

575
00:29:12.079 --> 00:29:15.119
<v Speaker 2>Page proof that in the early stages of evaporation, the

576
00:29:15.200 --> 00:29:18.720
<v Speaker 2>radiation behaves exactly as Hawking predicted. It comes out looking

577
00:29:18.759 --> 00:29:23.000
<v Speaker 2>completely random. The entanglement entropy climbs steadily upward.

578
00:29:23.240 --> 00:29:26.279
<v Speaker 3>It looks like pure noise, but page proof. There is

579
00:29:26.319 --> 00:29:27.480
<v Speaker 3>a tipping point, right.

580
00:29:27.440 --> 00:29:31.319
<v Speaker 2>Yes, Because the radiation is quantum mechanically entangled with the

581
00:29:31.319 --> 00:29:34.200
<v Speaker 2>remaining states inside the black hole. There is a hard

582
00:29:34.240 --> 00:29:38.119
<v Speaker 2>mathematical limit. When the black hole is evaporated to approximately

583
00:29:38.160 --> 00:29:41.240
<v Speaker 2>half of its original mass, you hit a critical moment

584
00:29:41.319 --> 00:29:42.960
<v Speaker 2>known as the page time.

585
00:29:43.559 --> 00:29:45.839
<v Speaker 3>What exactly happens at the page time At.

586
00:29:45.720 --> 00:29:49.119
<v Speaker 2>This halfway point, the shrinking black hole simply doesn't possess

587
00:29:49.200 --> 00:29:52.880
<v Speaker 2>enough remaining surface area to remain entangled with the massive,

588
00:29:53.000 --> 00:29:57.240
<v Speaker 2>growing cloud of radiation outside. The internal data capacity is

589
00:29:57.279 --> 00:30:00.680
<v Speaker 2>tapped out, so it's full. It's totally full. Therefore, forced

590
00:30:00.759 --> 00:30:05.200
<v Speaker 2>by the absolute mathematical requirement of unitarity, the specific information

591
00:30:05.319 --> 00:30:08.200
<v Speaker 2>must start leaking out into the radiation, so the graph peaks.

592
00:30:08.279 --> 00:30:10.920
<v Speaker 3>The graph peaks at the page time, and then the

593
00:30:11.079 --> 00:30:15.799
<v Speaker 3>entanglement entropy drastically drops it curves downward. Every new particle

594
00:30:15.799 --> 00:30:19.480
<v Speaker 3>emitted after the page time carries highly specific information that

595
00:30:19.599 --> 00:30:21.839
<v Speaker 3>is deeply correlated with the early radiation.

596
00:30:22.119 --> 00:30:25.599
<v Speaker 2>By the time the black hole evaporates completely, the entanglement

597
00:30:25.799 --> 00:30:29.680
<v Speaker 2>entropy hits zero. All the information has been transferred to

598
00:30:29.759 --> 00:30:30.759
<v Speaker 2>the radiation cloud.

599
00:30:31.000 --> 00:30:35.279
<v Speaker 3>This is the famous page curve, an inverted V shape

600
00:30:35.720 --> 00:30:36.880
<v Speaker 3>up peak down.

601
00:30:37.279 --> 00:30:39.839
<v Speaker 2>Here's where it gets really interesting. I want to use

602
00:30:39.880 --> 00:30:42.759
<v Speaker 2>a visual analogy to make this mechanism intuitive for you listening.

603
00:30:43.519 --> 00:30:46.759
<v Speaker 2>Imagine the black hole is spitting out pieces of a

604
00:30:46.839 --> 00:30:51.000
<v Speaker 2>massive billion piece jigsaw puzzle, a quantum puzzle. Right for

605
00:30:51.079 --> 00:30:52.839
<v Speaker 2>the first half of the black hole's life, you are

606
00:30:52.839 --> 00:30:55.759
<v Speaker 2>standing out in space catching these puzzle pieces, but you

607
00:30:55.799 --> 00:30:57.960
<v Speaker 2>only have a fraction of the puzzle. You look at

608
00:30:57.960 --> 00:31:00.160
<v Speaker 2>the pieces. One is a bit of blue sky, one

609
00:31:00.200 --> 00:31:02.519
<v Speaker 2>is a patch of green grass. None of them connect.

610
00:31:02.640 --> 00:31:05.720
<v Speaker 3>It just looks like a chaotic, meaningless pile of cardboard.

611
00:31:05.480 --> 00:31:09.559
<v Speaker 2>Exactly the messiness the entropy is rising. This perfectly matches

612
00:31:09.559 --> 00:31:12.880
<v Speaker 2>Hawkings observation that the early radiation looks like generic noise.

613
00:31:13.039 --> 00:31:15.839
<v Speaker 3>But then you hit the halfway mark the page time,

614
00:31:16.039 --> 00:31:17.440
<v Speaker 3>you've collected half the pieces.

615
00:31:18.119 --> 00:31:22.000
<v Speaker 2>Now something profound shifts because you possess half the system.

616
00:31:22.319 --> 00:31:25.319
<v Speaker 2>The statistical probability of a new piece connecting to an

617
00:31:25.319 --> 00:31:27.759
<v Speaker 2>old piece just skyrocket.

618
00:31:27.799 --> 00:31:28.680
<v Speaker 3>It has to connect.

619
00:31:28.799 --> 00:31:31.000
<v Speaker 2>Right, the black hole spits out a new piece and

620
00:31:31.039 --> 00:31:33.519
<v Speaker 2>it perfectly bridges the blue sky and the green grass.

621
00:31:33.960 --> 00:31:39.240
<v Speaker 2>Suddenly correlations emerge. The chaotic pile starts rapidly forming a clear,

622
00:31:39.599 --> 00:31:40.480
<v Speaker 2>defined picture.

623
00:31:40.680 --> 00:31:43.960
<v Speaker 3>The messiness decreases, the entropy goes down, and when.

624
00:31:43.799 --> 00:31:46.279
<v Speaker 2>The final piece is emitted and the black hole vanishes,

625
00:31:46.720 --> 00:31:49.200
<v Speaker 2>you don't have a pile of random cardboard. You have

626
00:31:49.240 --> 00:31:51.839
<v Speaker 2>a perfectly assembled picture of the encyclopedia.

627
00:31:51.960 --> 00:31:54.799
<v Speaker 3>It is a phenomenal way to visualize the transfer of

628
00:31:54.880 --> 00:31:59.440
<v Speaker 3>quantum entanglement. The page curve provided a mathematical lifeline. It

629
00:31:59.480 --> 00:32:02.799
<v Speaker 3>showed the phi x community exactly what a unitary evaporation

630
00:32:02.920 --> 00:32:04.400
<v Speaker 3>process actually looks like.

631
00:32:04.720 --> 00:32:06.799
<v Speaker 2>But it was a bit of a hollow victory, wasn't it?

632
00:32:06.880 --> 00:32:10.079
<v Speaker 2>Because Page proved what the graph should look like to

633
00:32:10.160 --> 00:32:13.119
<v Speaker 2>save physics, but he didn't explain the mechanism.

634
00:32:13.279 --> 00:32:15.880
<v Speaker 3>He didn't point to Hawkings math and say, ah, here

635
00:32:15.960 --> 00:32:19.000
<v Speaker 3>is the faulty equation that allows the puzzle pieces to connect.

636
00:32:19.240 --> 00:32:22.960
<v Speaker 2>He provided the destination, but not the vehicle. He proved

637
00:32:22.960 --> 00:32:26.359
<v Speaker 2>that if information is conserved, the page curve is the result.

638
00:32:26.880 --> 00:32:30.279
<v Speaker 2>But the physics community was left staring at a massive gap.

639
00:32:31.359 --> 00:32:33.640
<v Speaker 2>How does the black hole actually manage to encode the

640
00:32:33.720 --> 00:32:35.839
<v Speaker 2>data into the radiation.

641
00:32:35.759 --> 00:32:39.839
<v Speaker 3>Which triggers a decade's long theoretical arms race. Physicists knew

642
00:32:39.880 --> 00:32:44.119
<v Speaker 3>that Hawking's semi classical approximation, where he treated gravity as

643
00:32:44.160 --> 00:32:48.599
<v Speaker 3>a smooth classical background while treating the particles as quantum fields,

644
00:32:48.960 --> 00:32:51.880
<v Speaker 3>must have missed a deeply subtle mechanism.

645
00:32:51.559 --> 00:32:54.240
<v Speaker 2>Which leads us to the first major conceptual lead in

646
00:32:54.319 --> 00:32:58.079
<v Speaker 2>solving the paradox, subtle encoding and the holographic principle.

647
00:32:58.400 --> 00:33:01.200
<v Speaker 3>Let's look at the subtle encoding first. The idea was

648
00:33:01.240 --> 00:33:03.559
<v Speaker 3>that Hawking's math was just slightly too blunt.

649
00:33:03.720 --> 00:33:06.640
<v Speaker 2>The radiation isn't perfectly thermal, It's almost thermal, but not

650
00:33:06.759 --> 00:33:07.440
<v Speaker 2>quite right.

651
00:33:07.519 --> 00:33:10.839
<v Speaker 3>The proposition was that the information is encoded in hypercomplex

652
00:33:11.039 --> 00:33:12.559
<v Speaker 3>non local correlations.

653
00:33:12.839 --> 00:33:15.960
<v Speaker 2>Non local correlations, meaning, yeah, the data isn't stamped onto

654
00:33:16.000 --> 00:33:17.799
<v Speaker 2>a single outgoing photop exactly.

655
00:33:17.839 --> 00:33:20.799
<v Speaker 3>The information is smeared out. It's distributed in the quantum

656
00:33:20.799 --> 00:33:23.920
<v Speaker 3>relationships between a particle emitted today and a particle emitted

657
00:33:24.160 --> 00:33:25.200
<v Speaker 3>a billion years ago.

658
00:33:25.400 --> 00:33:28.319
<v Speaker 2>So if you capture a single particle of Hawking radiation,

659
00:33:28.720 --> 00:33:31.319
<v Speaker 2>it is completely indistinguishable from random heat.

660
00:33:31.519 --> 00:33:35.119
<v Speaker 3>But if you analyze the entire massive cloud of radiation

661
00:33:35.279 --> 00:33:40.559
<v Speaker 3>in its totality, evaluating the quantum entanglement spanning across billions

662
00:33:40.559 --> 00:33:43.799
<v Speaker 3>of light years, the whole contains the data.

663
00:33:43.880 --> 00:33:46.799
<v Speaker 2>It's like a cryptographic key where the data is fractured

664
00:33:46.839 --> 00:33:49.759
<v Speaker 2>across a billion distinct hard drives. If you only look

665
00:33:49.799 --> 00:33:53.200
<v Speaker 2>at one drive, it's just binary gibberish. You need all

666
00:33:53.240 --> 00:33:54.519
<v Speaker 2>of them to resolve the file.

667
00:33:54.640 --> 00:33:58.960
<v Speaker 3>And physicists argued that Hawking's semi classical calculation missed these

668
00:33:58.960 --> 00:34:02.480
<v Speaker 3>subtle correlations because it didn't incorporate the microscopic details of

669
00:34:02.519 --> 00:34:05.519
<v Speaker 3>quantum gravity. It's moved over the fine details.

670
00:34:05.680 --> 00:34:09.360
<v Speaker 2>But asserting that subtle correlations exist is very different from

671
00:34:09.360 --> 00:34:13.639
<v Speaker 2>proving it mathematically. To actually prove it, physicists needed a

672
00:34:13.679 --> 00:34:15.639
<v Speaker 2>completely new theoretical lens.

673
00:34:15.679 --> 00:34:17.800
<v Speaker 3>If we connect this to the bigger picture, this birth

674
00:34:17.920 --> 00:34:21.559
<v Speaker 3>the holographic principle. This was a radical reimagining of reality,

675
00:34:21.639 --> 00:34:23.559
<v Speaker 3>champion by Gerard Hooft and Leonard Suskin.

676
00:34:23.760 --> 00:34:26.360
<v Speaker 2>When most people hear the word hologram, they think of

677
00:34:26.400 --> 00:34:30.320
<v Speaker 2>a science fiction projection Princess Leah and Star Wars, or

678
00:34:30.480 --> 00:34:33.639
<v Speaker 2>the shiny emblem on a credit card, a three dimensional

679
00:34:33.719 --> 00:34:36.400
<v Speaker 2>image generated from a two dimensional surface.

680
00:34:36.360 --> 00:34:39.920
<v Speaker 3>And that is actually the perfect conceptual starting point. In

681
00:34:39.960 --> 00:34:43.559
<v Speaker 3>the nineteen nineties, Suskind and Uft looked back at Beekenstein's

682
00:34:43.679 --> 00:34:47.360
<v Speaker 3>entropy formula the discovery that a black hole's maximum information

683
00:34:47.559 --> 00:34:51.239
<v Speaker 3>capacity scales with its two D surface area, not its

684
00:34:51.280 --> 00:34:52.519
<v Speaker 3>three D volume.

685
00:34:52.199 --> 00:34:54.039
<v Speaker 2>The bucket lid, not the bucket depth.

686
00:34:54.559 --> 00:34:57.679
<v Speaker 3>They asked a staggering question. What if this isn't just

687
00:34:57.719 --> 00:35:00.039
<v Speaker 3>a quirky rule for black holes. What if this, this

688
00:35:00.159 --> 00:35:03.599
<v Speaker 3>area law is a fundamental property of the entire.

689
00:35:03.400 --> 00:35:04.960
<v Speaker 2>Universe, the entire universe.

690
00:35:05.079 --> 00:35:08.760
<v Speaker 3>Yes, what if all the physical events, particles, and gravitational

691
00:35:08.800 --> 00:35:12.239
<v Speaker 3>forces occurring in any three dimensional volume of space can

692
00:35:12.280 --> 00:35:15.760
<v Speaker 3>be perfectly exhaustively encoded as quantum data on a two

693
00:35:15.800 --> 00:35:17.719
<v Speaker 3>dimensional boundary surrounding that space.

694
00:35:18.000 --> 00:35:21.760
<v Speaker 2>It's an incredibly disorienting concept. It suggests that the three

695
00:35:21.840 --> 00:35:24.440
<v Speaker 2>D reality we experience, you, me, the room we are

696
00:35:24.440 --> 00:35:26.440
<v Speaker 2>sitting in is fundamentally a projection.

697
00:35:26.800 --> 00:35:30.400
<v Speaker 3>The true data of our reality is smeared across a distant,

698
00:35:30.559 --> 00:35:33.880
<v Speaker 3>lower dimensional boundary, much like a two D piece of

699
00:35:33.960 --> 00:35:37.920
<v Speaker 3>holographic film contains the intricate interference patterns of light that

700
00:35:38.000 --> 00:35:39.280
<v Speaker 3>project a three D image.

701
00:35:39.559 --> 00:35:43.280
<v Speaker 2>It challenges our most basic intuition about where things are located,

702
00:35:43.800 --> 00:35:47.679
<v Speaker 2>but it remained a largely philosophical idea until nineteen ninety seven,

703
00:35:47.960 --> 00:35:51.880
<v Speaker 2>when a brilliant physicist named Juan Maldasena gave the holographic

704
00:35:51.920 --> 00:35:56.360
<v Speaker 2>principle a rigorous, mathematically exact framework. It is known as

705
00:35:56.400 --> 00:36:01.159
<v Speaker 2>the ad SCFT correspondence ad SCFI. Okay, we need to

706
00:36:01.199 --> 00:36:04.039
<v Speaker 2>spend some time demystifying this acronym because it is arguably

707
00:36:04.280 --> 00:36:06.800
<v Speaker 2>one of the most important theoretical discoveries in the last

708
00:36:06.840 --> 00:36:07.840
<v Speaker 2>fifty years of physics.

709
00:36:07.880 --> 00:36:10.840
<v Speaker 3>We can break it down logically. ADS stands for anti

710
00:36:10.880 --> 00:36:15.039
<v Speaker 3>desitter space, CFT stands for conformal field theory. Let's imagine

711
00:36:15.039 --> 00:36:17.480
<v Speaker 3>a highly specialized theoretical universe.

712
00:36:17.599 --> 00:36:18.960
<v Speaker 2>Okay, I'm picturing a universe.

713
00:36:19.000 --> 00:36:21.679
<v Speaker 3>The interior volume of this universe, the three D bulk space,

714
00:36:21.800 --> 00:36:24.519
<v Speaker 3>is an anti desitter space. This means it has a

715
00:36:24.519 --> 00:36:27.840
<v Speaker 3>negative curvature. It acts somewhat like a mathematical box. Light

716
00:36:27.880 --> 00:36:29.440
<v Speaker 3>can travel from the center to the edge of the

717
00:36:29.519 --> 00:36:31.800
<v Speaker 3>universe and bounce back in a finite amount of time.

718
00:36:31.880 --> 00:36:33.719
<v Speaker 2>So it is a self contained three D universe with

719
00:36:33.760 --> 00:36:34.840
<v Speaker 2>an absolute.

720
00:36:34.440 --> 00:36:38.239
<v Speaker 3>Edge exactly within this three D interior. The laws of

721
00:36:38.239 --> 00:36:41.960
<v Speaker 3>physics include gravity. We have string theory operating in here.

722
00:36:42.480 --> 00:36:45.760
<v Speaker 3>Stars can collapse, planets can orbit, and black holes can form.

723
00:36:46.239 --> 00:36:48.320
<v Speaker 3>This is the ADS side of the duality.

724
00:36:48.440 --> 00:36:50.079
<v Speaker 2>A three D universe with gravity.

725
00:36:50.159 --> 00:36:53.159
<v Speaker 3>Now look at the absolute boundary of this universe, the

726
00:36:53.159 --> 00:36:56.079
<v Speaker 3>two D surface wrapping around the outside. On this surface,

727
00:36:56.159 --> 00:36:59.639
<v Speaker 3>a completely different set of physical laws governs reality. This

728
00:36:59.679 --> 00:37:02.800
<v Speaker 3>bound is governed by a conformal field.

729
00:37:02.519 --> 00:37:04.480
<v Speaker 2>Theory, a quantum field theory.

730
00:37:04.599 --> 00:37:08.719
<v Speaker 3>Yes, But critically, there is absolutely no gravity on this

731
00:37:08.760 --> 00:37:11.679
<v Speaker 3>two D boundary. It is a flat space governed purely

732
00:37:11.719 --> 00:37:14.840
<v Speaker 3>by quantum mechanics, with particles interacting through quantum fields.

733
00:37:14.920 --> 00:37:17.159
<v Speaker 2>So we have a three D interior featuring gravity and

734
00:37:17.239 --> 00:37:20.280
<v Speaker 2>black holes surrounded by a flat two D boundary featuring

735
00:37:20.320 --> 00:37:24.000
<v Speaker 2>only quantum mechanics and zero gravity. They sound like completely alien,

736
00:37:24.119 --> 00:37:25.679
<v Speaker 2>irreconcilable realities.

737
00:37:25.760 --> 00:37:29.719
<v Speaker 3>They do, But Maldacina achieves something breathtaking. He constructed a

738
00:37:29.719 --> 00:37:33.280
<v Speaker 3>mathematical dictionary that proves these two realities are exactly equivalent.

739
00:37:33.599 --> 00:37:37.280
<v Speaker 3>They are dual mathematical descriptions of the exact same physics.

740
00:37:36.920 --> 00:37:39.760
<v Speaker 2>Meaning every single event that happens in the three D

741
00:37:39.880 --> 00:37:45.239
<v Speaker 2>gravity universe has a mathematically identical corresponding event happening on

742
00:37:45.239 --> 00:37:46.559
<v Speaker 2>the two D quantum boundary.

743
00:37:46.599 --> 00:37:50.079
<v Speaker 3>Precisely, if two particles collide in the three D interior,

744
00:37:50.199 --> 00:37:53.239
<v Speaker 3>you can use Maldaicine's dictionary to translate that event out

745
00:37:53.239 --> 00:37:56.119
<v Speaker 3>to the boundary, and it perfectly corresponds to an interaction

746
00:37:56.519 --> 00:37:57.920
<v Speaker 3>in the quantum field theory.

747
00:37:58.280 --> 00:38:01.880
<v Speaker 2>It is a perfect lossless translation from a theory of

748
00:38:01.880 --> 00:38:05.280
<v Speaker 2>gravity to a theory of pure quantum mechanics. It is okay,

749
00:38:05.280 --> 00:38:08.119
<v Speaker 2>that is a beautiful mathematical construct. Yeah, but how does

750
00:38:08.159 --> 00:38:13.639
<v Speaker 2>this abstract geometry actually solve the black hole information paradox?

751
00:38:13.760 --> 00:38:17.079
<v Speaker 3>Because it constructs an iron clad logical trap. Let's form

752
00:38:17.119 --> 00:38:19.760
<v Speaker 3>a black hole inside the three D anti desitter space.

753
00:38:20.079 --> 00:38:22.679
<v Speaker 3>The star collapses, the black hole forms, and it begins

754
00:38:22.760 --> 00:38:25.800
<v Speaker 3>to emit Hawking radiation. We want to know does this

755
00:38:25.840 --> 00:38:27.760
<v Speaker 3>black hole destroy information?

756
00:38:28.000 --> 00:38:30.039
<v Speaker 2>We want to know if unitarity is violated in the

757
00:38:30.039 --> 00:38:30.760
<v Speaker 2>three D bulk.

758
00:38:30.960 --> 00:38:33.559
<v Speaker 3>Right, instead of trying to calculate the messy gravity math

759
00:38:33.639 --> 00:38:36.679
<v Speaker 3>in the interior, we use the dictionary. We project the

760
00:38:36.840 --> 00:38:39.880
<v Speaker 3>entire evaporation process out onto the two D boundary. We

761
00:38:39.920 --> 00:38:42.840
<v Speaker 3>watch how the corresponding boundary theory handles the evaporation.

762
00:38:43.239 --> 00:38:46.360
<v Speaker 2>But the boundary theory is a conformal field theory. It

763
00:38:46.440 --> 00:38:49.480
<v Speaker 2>is purely quantum mechanics, no gravity at all.

764
00:38:49.599 --> 00:38:53.239
<v Speaker 3>And what do we know about pure quantum mechanical systems?

765
00:38:53.679 --> 00:38:57.519
<v Speaker 2>They are governed by unitary operators. Information is strictly conserved.

766
00:38:57.960 --> 00:39:01.679
<v Speaker 2>It is mathematically impossible for a pure quantum field theory

767
00:39:02.000 --> 00:39:04.519
<v Speaker 2>to permanently delete data exactly.

768
00:39:04.920 --> 00:39:10.159
<v Speaker 3>The two D boundary theory is manifestly unarguably unitary. The

769
00:39:10.239 --> 00:39:12.920
<v Speaker 3>data on the boundary cannot be lost, it can only

770
00:39:12.960 --> 00:39:16.000
<v Speaker 3>be scrambled. And because Maldosina proved that the three D

771
00:39:16.119 --> 00:39:19.760
<v Speaker 3>interior is mathematically identical to the two D boundary, if.

772
00:39:19.599 --> 00:39:23.320
<v Speaker 2>The boundary preserves the data, the interior must preserve the data.

773
00:39:23.440 --> 00:39:26.400
<v Speaker 3>Yes, the formation and evaporation of the black hole in

774
00:39:26.440 --> 00:39:29.400
<v Speaker 3>the three D space must be a unitary process. The

775
00:39:29.440 --> 00:39:32.960
<v Speaker 3>information is not destroyed. Hawkings's claim of permanent dilution is

776
00:39:33.000 --> 00:39:35.679
<v Speaker 3>mathematically cornered and proven false by translation.

777
00:39:35.880 --> 00:39:39.960
<v Speaker 2>That is an astonishing intellectual maneuver. By projecting the gravitational

778
00:39:40.000 --> 00:39:42.760
<v Speaker 2>problem into a lower dimension that doesn't have gravity, you

779
00:39:42.960 --> 00:39:46.480
<v Speaker 2>literally guarantee that the information survives. The data is safe.

780
00:39:46.599 --> 00:39:49.199
<v Speaker 3>It was a massive psychological relief for the physics community.

781
00:39:49.239 --> 00:39:51.280
<v Speaker 3>It confirmed that quantum mechanics holds firm.

782
00:39:51.519 --> 00:39:55.159
<v Speaker 2>But wait, does it actually explain the mechanics of the escape.

783
00:39:55.360 --> 00:39:58.880
<v Speaker 2>The attic c oft translation proves that the information gets out.

784
00:39:59.159 --> 00:40:01.000
<v Speaker 2>But if I'm an ass or not inside the three

785
00:40:01.079 --> 00:40:03.920
<v Speaker 2>D space falling toward a black hole. I don't care

786
00:40:04.000 --> 00:40:06.119
<v Speaker 2>about a two D mathematical boundary at the edge of

787
00:40:06.199 --> 00:40:08.599
<v Speaker 2>the universe. I want to know how the data physically

788
00:40:08.639 --> 00:40:11.800
<v Speaker 2>traverses the event horizon in my local reality.

789
00:40:12.360 --> 00:40:16.280
<v Speaker 3>And that was the lingering frustration. Holography provided a broad,

790
00:40:16.480 --> 00:40:19.760
<v Speaker 3>indirect proof, but it lacked the nuts and bolts. It

791
00:40:19.800 --> 00:40:23.079
<v Speaker 3>didn't point to the specific local mechanism generating the page

792
00:40:23.079 --> 00:40:26.639
<v Speaker 3>curve during the evaporation process. Physicists wanted to see the

793
00:40:26.679 --> 00:40:27.800
<v Speaker 3>actual gears.

794
00:40:27.480 --> 00:40:30.039
<v Speaker 2>Turning, which ushers in the most recent and arguably most

795
00:40:30.119 --> 00:40:34.000
<v Speaker 2>promising breakthroughs in the field, a conceptual framework that finally

796
00:40:34.000 --> 00:40:37.880
<v Speaker 2>targets the local mechanism, the discovery of quantum extremal surfaces

797
00:40:38.079 --> 00:40:39.000
<v Speaker 2>and the island rule.

798
00:40:39.360 --> 00:40:41.639
<v Speaker 3>This is where the math gets incredibly complex, but the

799
00:40:41.760 --> 00:40:45.840
<v Speaker 3>underlying geometry is fascinating. For years, physicists struggled to calculate

800
00:40:45.880 --> 00:40:49.280
<v Speaker 3>the entanglement entropy of a Hawking radiation directly right, But

801
00:40:49.320 --> 00:40:52.199
<v Speaker 3>in twenty nineteen, several groups of physicists achieved a major

802
00:40:52.239 --> 00:40:56.639
<v Speaker 3>breakthrough using mathematical tools designed to measure entanglement through geometry.

803
00:40:56.880 --> 00:40:59.960
<v Speaker 2>Tools like the REU Takinagi formula, which links the entire

804
00:41:00.000 --> 00:41:02.880
<v Speaker 2>hangglement entropy of the boundary to the area of specific

805
00:41:02.960 --> 00:41:05.119
<v Speaker 2>minimal surfaces deep within the bulk space.

806
00:41:05.519 --> 00:41:09.719
<v Speaker 3>Yes, they applied these geometric tools to the evaporating black hole,

807
00:41:10.239 --> 00:41:13.039
<v Speaker 3>and for the first time, without relying entirely on the

808
00:41:13.079 --> 00:41:16.360
<v Speaker 3>holographic boundary, they were able to calculate the entropy of

809
00:41:16.360 --> 00:41:18.519
<v Speaker 3>the radiation from first principles.

810
00:41:18.559 --> 00:41:20.239
<v Speaker 2>And what did the calculation yield?

811
00:41:20.519 --> 00:41:23.559
<v Speaker 3>The math naturally produce the exact shape of the page curve.

812
00:41:23.800 --> 00:41:27.679
<v Speaker 2>Wow. It showed the entropy rising, hitting a peak at

813
00:41:27.719 --> 00:41:29.880
<v Speaker 2>the page time, and curving back down to zero.

814
00:41:30.000 --> 00:41:33.000
<v Speaker 3>It was a monumental achievement. The calculation proved that late

815
00:41:33.039 --> 00:41:36.400
<v Speaker 3>stage Hawking radiation is in fact highly entangled with the

816
00:41:36.400 --> 00:41:40.679
<v Speaker 3>early radiation. Gradually purifying the quantum state and reconstructing the data,

817
00:41:41.159 --> 00:41:43.840
<v Speaker 3>they found the mechanical vehicle don Page had demanded in

818
00:41:43.920 --> 00:41:45.039
<v Speaker 3>nineteen ninety three.

819
00:41:45.280 --> 00:41:48.480
<v Speaker 2>But physics rarely hands out free lunches. I'm guessing the

820
00:41:48.480 --> 00:41:51.800
<v Speaker 2>mathematical vehicle they found came with some deeply weird baggage.

821
00:41:52.000 --> 00:41:55.800
<v Speaker 3>Profoundly weird baggage, because to get the formulas to spit

822
00:41:55.840 --> 00:41:58.920
<v Speaker 3>out the page curve, the math required them to include

823
00:41:59.000 --> 00:42:03.880
<v Speaker 3>a new, una expected geometric contribution. They found that calculating

824
00:42:03.880 --> 00:42:07.719
<v Speaker 3>the entropy of the external radiation required including a quantum

825
00:42:07.760 --> 00:42:10.400
<v Speaker 3>extremal surface that emerges inside the black hole.

826
00:42:10.840 --> 00:42:13.480
<v Speaker 2>Let's clearly define what this means. What is this surface

827
00:42:13.519 --> 00:42:14.719
<v Speaker 2>and what is the island.

828
00:42:15.320 --> 00:42:18.039
<v Speaker 3>Think of the island as a distinct physical region of

829
00:42:18.079 --> 00:42:21.360
<v Speaker 3>space time located entirely inside the event horizon of the

830
00:42:21.400 --> 00:42:24.639
<v Speaker 3>black hole. It is deep inside the inescapable vault.

831
00:42:24.760 --> 00:42:26.760
<v Speaker 2>Okay, the island is inside.

832
00:42:26.400 --> 00:42:30.639
<v Speaker 3>But the mechanics of entanglement dictate something completely counterintuitive. As

833
00:42:30.679 --> 00:42:34.199
<v Speaker 3>the black hole evaporates and emits radiation, the entanglement between

834
00:42:34.199 --> 00:42:37.159
<v Speaker 3>the radiation and the interior grows. Okay, when you reach

835
00:42:37.199 --> 00:42:39.599
<v Speaker 3>the page, the halfway point of phase transition occurs in

836
00:42:39.639 --> 00:42:43.079
<v Speaker 3>the math. The calculations reveal that to fully accurately describe

837
00:42:43.079 --> 00:42:45.760
<v Speaker 3>the quantum state of the Hawking radiation floating out in

838
00:42:45.800 --> 00:42:49.000
<v Speaker 3>deep space, you must mathematically include the island.

839
00:42:49.320 --> 00:42:51.519
<v Speaker 2>Let me push back on this because it challenges basic

840
00:42:51.559 --> 00:42:55.679
<v Speaker 2>spacial logic. How can a physical region of space buried

841
00:42:55.719 --> 00:42:59.239
<v Speaker 2>behind a boundary from which light cannot escape be mathematically

842
00:42:59.280 --> 00:43:02.199
<v Speaker 2>treated as a component of the radiation cloud. Millions of

843
00:43:02.280 --> 00:43:02.960
<v Speaker 2>light years away.

844
00:43:03.039 --> 00:43:07.760
<v Speaker 3>It forces us to entirely rethink locality. Our classical intuition

845
00:43:07.880 --> 00:43:11.679
<v Speaker 3>treats space as a rigid container. Object as inside the box,

846
00:43:11.719 --> 00:43:14.639
<v Speaker 3>object B is outside the box, and they are separated

847
00:43:14.679 --> 00:43:15.800
<v Speaker 3>by a physical distance.

848
00:43:16.320 --> 00:43:18.440
<v Speaker 2>Right, If I am holding a piece of radiation out

849
00:43:18.440 --> 00:43:21.079
<v Speaker 2>in space, I am holding it here, not there.

850
00:43:21.239 --> 00:43:26.840
<v Speaker 3>But quantum entanglement ignores spatial separation entirely. Entanglement weaves distinct

851
00:43:26.880 --> 00:43:30.880
<v Speaker 3>regions of reality together. The island formula mathematically proves that

852
00:43:30.920 --> 00:43:34.800
<v Speaker 3>the exterior radiation is so massively comprehensively entangled with the

853
00:43:34.840 --> 00:43:37.360
<v Speaker 3>interior region of the black hole that they cease to

854
00:43:37.400 --> 00:43:41.800
<v Speaker 3>be distinct systems. They basically fuse into a single quantum entity.

855
00:43:42.039 --> 00:43:44.519
<v Speaker 2>So if I am sitting in a observatory far away

856
00:43:45.000 --> 00:43:48.440
<v Speaker 2>scooping up Hawking radiation in a magnetic trap, I don't

857
00:43:48.440 --> 00:43:51.679
<v Speaker 2>just possess photons in a strict quantum information sense. The

858
00:43:51.880 --> 00:43:55.000
<v Speaker 2>entanglement is so dense that my trap literally contains the

859
00:43:55.039 --> 00:43:56.679
<v Speaker 2>interior of the black hole. Yes.

860
00:43:57.519 --> 00:44:01.599
<v Speaker 3>This is known as entanglement wedge reconstruction. It implies that

861
00:44:01.639 --> 00:44:05.480
<v Speaker 3>if you possessed a miraculously advanced quantum computer, you could

862
00:44:05.519 --> 00:44:08.679
<v Speaker 3>run operations on the radiation you collected in deep space,

863
00:44:09.239 --> 00:44:12.159
<v Speaker 3>and you would instantaneously manipulate the physical state of the

864
00:44:12.159 --> 00:44:14.039
<v Speaker 3>island deep inside the black hole.

865
00:44:14.360 --> 00:44:17.440
<v Speaker 2>The inside of the black hole is no longer truly inside.

866
00:44:18.039 --> 00:44:22.119
<v Speaker 2>The spatial boundary has been rendered totally irrelevant by quantum entanglement.

867
00:44:22.400 --> 00:44:26.320
<v Speaker 3>The event horizon remains an absolute barrier for classical objects,

868
00:44:26.679 --> 00:44:30.480
<v Speaker 3>but it is highly poorous to quantum information. The paradox

869
00:44:30.519 --> 00:44:33.800
<v Speaker 3>is resolved because the information never truly falls permanently behind

870
00:44:33.880 --> 00:44:35.320
<v Speaker 3>an impenetrable wall.

871
00:44:35.320 --> 00:44:38.960
<v Speaker 2>Because through massive entanglement, the interior literally becomes part of

872
00:44:39.000 --> 00:44:42.800
<v Speaker 2>the exterior. The data escapes because the definitions of inside

873
00:44:42.840 --> 00:44:46.920
<v Speaker 2>outside overlap exactly. It is a stunning, elegant mathematical maneuver.

874
00:44:46.960 --> 00:44:49.800
<v Speaker 2>It saves quantum mechanics, and it saves the encyclopedia. But

875
00:44:49.880 --> 00:44:53.159
<v Speaker 2>I have to imagine that redefining spirtial locality so aggressively

876
00:44:53.519 --> 00:44:56.000
<v Speaker 2>makes a lot of physicists deeply uncomfortable.

877
00:44:56.159 --> 00:44:59.559
<v Speaker 3>It really does. While the island calculation is widely celebrated

878
00:44:59.559 --> 00:45:03.280
<v Speaker 3>for success ustfully reproducing the page curve, the physical interpretation

879
00:45:03.440 --> 00:45:05.519
<v Speaker 3>of what the island actually means for the fabric of

880
00:45:05.599 --> 00:45:07.920
<v Speaker 3>space is fiercely debated.

881
00:45:07.599 --> 00:45:10.719
<v Speaker 2>Which leads us to the radical alternatives, because if you

882
00:45:10.760 --> 00:45:13.280
<v Speaker 2>refuse to accept that the inside of a black hole

883
00:45:13.320 --> 00:45:16.440
<v Speaker 2>magically overlaps with deep space, you have to look for

884
00:45:16.480 --> 00:45:20.119
<v Speaker 2>other ways to preserve unitarity, and some of those alternatives

885
00:45:20.199 --> 00:45:22.800
<v Speaker 2>demand a very heavy toll from our classical intuition.

886
00:45:23.039 --> 00:45:25.800
<v Speaker 3>This raises an important question, and it brings us to

887
00:45:25.880 --> 00:45:29.199
<v Speaker 3>a massively controversial paper published in twenty twelve by four

888
00:45:29.199 --> 00:45:34.079
<v Speaker 3>physicists Almhari, Marlv Polchinski, and Sully. It is known as

889
00:45:34.119 --> 00:45:37.400
<v Speaker 3>the Amps paradox or the firewall hypothesis.

890
00:45:37.400 --> 00:45:40.360
<v Speaker 2>The firewall this is where physics gets downright violent. What

891
00:45:40.440 --> 00:45:41.960
<v Speaker 2>were Amps trying to selve?

892
00:45:42.320 --> 00:45:44.719
<v Speaker 3>They were trying to construct a model that achieved three

893
00:45:44.760 --> 00:45:49.760
<v Speaker 3>specific things simultaneously. First, unitarity must be preserved. The encyclopedia

894
00:45:49.840 --> 00:45:53.039
<v Speaker 3>must get out. Second, standard quantum field theory must function

895
00:45:53.119 --> 00:45:57.119
<v Speaker 3>normally outside the event horizon. Third, they wanted to preserve

896
00:45:57.199 --> 00:46:03.360
<v Speaker 3>Einstein's equivalence principle salute cornerstone of general relativity, which states

897
00:46:03.360 --> 00:46:06.880
<v Speaker 3>that an observer and freefall shouldn't feel anything unusual happening

898
00:46:06.920 --> 00:46:10.079
<v Speaker 3>in their local environment even as they cross an event horizon.

899
00:46:10.440 --> 00:46:14.239
<v Speaker 3>The horizon should be smooth, empty space, no drama.

900
00:46:14.400 --> 00:46:17.880
<v Speaker 2>They wanted a perfect universe where quantum mechanics and relativity

901
00:46:17.960 --> 00:46:20.199
<v Speaker 2>both emerge totally unscathed.

902
00:46:20.519 --> 00:46:23.920
<v Speaker 3>But when they rigorously analyze the quantum entanglement required to

903
00:46:23.960 --> 00:46:28.480
<v Speaker 3>make the information escape, they hit an insurmountable mathematical roadblock,

904
00:46:28.800 --> 00:46:31.599
<v Speaker 3>a concept known as the monogamy of entanglement.

905
00:46:31.679 --> 00:46:35.159
<v Speaker 2>Monogamy of entanglement, This means a quantum particle can only

906
00:46:35.199 --> 00:46:38.639
<v Speaker 2>be fully maximally entangled with one other system at a time.

907
00:46:38.719 --> 00:46:41.800
<v Speaker 3>Precisely, you cannot be maximally entangled with system A and

908
00:46:41.880 --> 00:46:46.119
<v Speaker 3>simultaneously maximally entangled with System B. Now apply this rule

909
00:46:46.159 --> 00:46:50.039
<v Speaker 3>to a newly created particle of Hawking radiation just outside

910
00:46:50.079 --> 00:46:50.920
<v Speaker 3>the event horizon.

911
00:46:51.079 --> 00:46:54.320
<v Speaker 2>Okay, let's track the required entanglements for the information to

912
00:46:54.440 --> 00:46:57.480
<v Speaker 2>escape and produce the page curve. This new particle must

913
00:46:57.480 --> 00:47:00.280
<v Speaker 2>be deeply entangled with all the old Hawking radiation that

914
00:47:00.280 --> 00:47:02.880
<v Speaker 2>has already escaped into space. It has to connect to

915
00:47:02.920 --> 00:47:03.360
<v Speaker 2>the puzzle.

916
00:47:03.719 --> 00:47:07.119
<v Speaker 3>Yes, the new particle must be married to the early

917
00:47:07.199 --> 00:47:11.239
<v Speaker 3>radiation cloud to ensure unitarity. But remember the physical mechanism

918
00:47:11.239 --> 00:47:15.039
<v Speaker 3>of Hawking radiation we discussed earlier. The particle was created

919
00:47:15.039 --> 00:47:17.760
<v Speaker 3>from a virtual vacuum pair that was torn apart by

920
00:47:17.840 --> 00:47:20.920
<v Speaker 3>tidal forces right, and to satisfy the local rules of

921
00:47:20.960 --> 00:47:21.920
<v Speaker 3>quantum field theory.

922
00:47:21.960 --> 00:47:25.679
<v Speaker 2>In a smooth vacuum, the particle on the outside must

923
00:47:25.679 --> 00:47:29.440
<v Speaker 2>be heavily entangled with its partner particle that fell inside

924
00:47:29.440 --> 00:47:30.119
<v Speaker 2>the black hole.

925
00:47:30.360 --> 00:47:33.199
<v Speaker 3>So the escaping particle must be married to the old

926
00:47:33.280 --> 00:47:36.679
<v Speaker 3>radiation far away and married to the partner particle falling inward.

927
00:47:37.119 --> 00:47:40.079
<v Speaker 2>But the monogamy of entanglement extressly forbids that. It's a

928
00:47:40.079 --> 00:47:44.559
<v Speaker 2>fundamental contradiction. The math demands a single particle be maximally

929
00:47:44.719 --> 00:47:47.320
<v Speaker 2>entangled with two completely independent systems.

930
00:47:47.440 --> 00:47:51.199
<v Speaker 3>It is a logical impossibility. A MPs realized that their

931
00:47:51.239 --> 00:47:55.039
<v Speaker 3>three required pillars, unitarity, normal quantum field theory, and a

932
00:47:55.079 --> 00:47:58.559
<v Speaker 3>smooth event horizon were mutually incompatible. You can only pick two.

933
00:47:59.079 --> 00:48:01.800
<v Speaker 3>One pillar has to be destroyed to resolve the paradox.

934
00:48:02.119 --> 00:48:04.920
<v Speaker 2>If they want to save quantum mechanics, they have to

935
00:48:04.960 --> 00:48:08.360
<v Speaker 2>physically sever one of those entanglements. They can't sever the

936
00:48:08.440 --> 00:48:11.599
<v Speaker 2>link to the early radiation because that would destroy the

937
00:48:11.679 --> 00:48:14.320
<v Speaker 2>data and violate unitarity, so they have to sever the

938
00:48:14.360 --> 00:48:16.159
<v Speaker 2>link across the event horizon.

939
00:48:16.320 --> 00:48:19.400
<v Speaker 3>They have to physically break the quantum bond between the

940
00:48:19.519 --> 00:48:23.480
<v Speaker 3>escaping particle and the infalling partner, but breaking a quantum

941
00:48:23.599 --> 00:48:27.159
<v Speaker 3>entanglement bond releases a tremendous amount of energy.

942
00:48:26.920 --> 00:48:30.199
<v Speaker 2>And this is happening continuously across the entire spherical boundary

943
00:48:30.239 --> 00:48:33.519
<v Speaker 2>of the black hole for billions of years, which.

944
00:48:33.320 --> 00:48:36.800
<v Speaker 3>Means an unfathomable amount of energy is released exactly at

945
00:48:36.840 --> 00:48:40.320
<v Speaker 3>the event horizon. Polchinski and his colleagues concluded that this

946
00:48:40.440 --> 00:48:44.800
<v Speaker 3>severed entanglement creates a literal wall of high energy quanta,

947
00:48:45.360 --> 00:48:46.280
<v Speaker 3>a firewall.

948
00:48:46.440 --> 00:48:50.400
<v Speaker 2>So the event horizon isn't an invisible, smooth mathematical line anymore.

949
00:48:51.159 --> 00:48:55.280
<v Speaker 2>It is a blazing, infinitely hot surface of incinerating energy.

950
00:48:55.400 --> 00:48:58.000
<v Speaker 3>Yes, and the cost of this hypothesis is that it

951
00:48:58.039 --> 00:49:01.239
<v Speaker 3>completely obliterates Einstein's equivalents principle.

952
00:49:01.000 --> 00:49:03.159
<v Speaker 2>Because if an astronaut falls toward a black hole with

953
00:49:03.239 --> 00:49:07.199
<v Speaker 2>a firewall, they don't experience a smooth drama free crossing

954
00:49:07.960 --> 00:49:11.199
<v Speaker 2>the exact microsecond they touch the event horizon. They hit

955
00:49:11.239 --> 00:49:15.079
<v Speaker 2>a solid wall of blazing radiation and are instantly incinerated

956
00:49:15.119 --> 00:49:16.760
<v Speaker 2>into their constituent quantum bits.

957
00:49:17.199 --> 00:49:20.320
<v Speaker 3>You preserve the data, you save quantum mechanics, but you

958
00:49:20.360 --> 00:49:25.239
<v Speaker 3>sacrifice general relativity right at the boundary. The smooth geometry

959
00:49:25.239 --> 00:49:26.920
<v Speaker 3>of space time is ripped apart.

960
00:49:27.320 --> 00:49:31.199
<v Speaker 2>It is a conceptually violent solution. Polchinski himself didn't necessarily

961
00:49:31.239 --> 00:49:33.920
<v Speaker 2>want it to be true, but he argued that mathematically

962
00:49:33.960 --> 00:49:37.159
<v Speaker 2>it was the most conservative logical outcome. If you prioritize

963
00:49:37.199 --> 00:49:38.079
<v Speaker 2>quantum mechanics.

964
00:49:38.199 --> 00:49:41.480
<v Speaker 3>It forces a brutal choice. But the sheer ugliness of

965
00:49:41.519 --> 00:49:45.840
<v Speaker 3>a massive, unexplained firewall hovering in space pushed other physicists

966
00:49:45.840 --> 00:49:48.960
<v Speaker 3>to search for an even deeper, more fundamental truth. If

967
00:49:48.960 --> 00:49:51.880
<v Speaker 3>we despise firewalls and we struggle with the non locality

968
00:49:51.920 --> 00:49:54.599
<v Speaker 3>of islands, perhaps we are looking at the problem through

969
00:49:54.599 --> 00:49:55.960
<v Speaker 3>the wrong lens entirely.

970
00:49:56.280 --> 00:49:58.440
<v Speaker 2>Perhaps the very language we are using to describe the

971
00:49:58.440 --> 00:50:02.599
<v Speaker 2>paradox as flawed. This brings us to the deepest conceptual frontier,

972
00:50:02.960 --> 00:50:04.000
<v Speaker 2>emergent space time.

973
00:50:04.239 --> 00:50:07.840
<v Speaker 3>We have spent this entire discussion relying on classical concepts.

974
00:50:08.119 --> 00:50:11.039
<v Speaker 3>We talk about the encyclopedia falling inside the black hole

975
00:50:11.079 --> 00:50:14.159
<v Speaker 3>and the radiation escaping to the outside. We rely heavily

976
00:50:14.199 --> 00:50:18.039
<v Speaker 3>on the concepts of distance, location, and geometry.

977
00:50:17.760 --> 00:50:22.000
<v Speaker 2>Because space and time are the absolute bedrock of reality.

978
00:50:22.639 --> 00:50:25.320
<v Speaker 2>They are the stage on which all physics takes place.

979
00:50:25.719 --> 00:50:28.440
<v Speaker 3>But what if space time is not the fundamental stage.

980
00:50:28.840 --> 00:50:32.559
<v Speaker 3>What if space and time are illusions. Let's consider a

981
00:50:32.599 --> 00:50:37.119
<v Speaker 3>macroscopic property like temperature. Temperature is not a fundamental property

982
00:50:37.119 --> 00:50:39.800
<v Speaker 3>of the universe. A single atom doesn't have a.

983
00:50:39.719 --> 00:50:43.199
<v Speaker 2>Temperature, right, Temperature is just a macroscopic illusion created by

984
00:50:43.199 --> 00:50:46.719
<v Speaker 2>the microscopic kinetic motion of billions of atoms jiggling against

985
00:50:46.760 --> 00:50:49.400
<v Speaker 2>each other. It emerges from the aggregate behavior.

986
00:50:49.559 --> 00:50:52.280
<v Speaker 3>What a space time itself emerges in exactly the same way.

987
00:50:52.599 --> 00:50:55.559
<v Speaker 3>What if distance and geometry are not fundamental but are

988
00:50:55.599 --> 00:51:00.159
<v Speaker 3>macroscopic manifestations of a deeper underlying quantum network, and the

989
00:51:00.199 --> 00:51:02.960
<v Speaker 3>threads connecting that network are quantum entanglement.

990
00:51:03.480 --> 00:51:07.519
<v Speaker 2>So space doesn't dictate entanglement. Entanglement creates space exactly.

991
00:51:07.880 --> 00:51:11.239
<v Speaker 3>This line of thinking led to a profound theoretical proposal

992
00:51:11.400 --> 00:51:13.960
<v Speaker 3>by Susskine and Maldasina known as er.

993
00:51:14.320 --> 00:51:17.559
<v Speaker 2>EPR okay Let's unpack er EPR.

994
00:51:17.760 --> 00:51:21.880
<v Speaker 3>In nineteen thirty five, Albert Einstein co authored two groundbreaking papers.

995
00:51:22.400 --> 00:51:25.800
<v Speaker 3>One paper, written with Nathan Rosen, described the mathematics of

996
00:51:25.840 --> 00:51:29.519
<v Speaker 3>wormholes tunnels connecting distant regions of space time. These are

997
00:51:29.559 --> 00:51:32.079
<v Speaker 3>known as Einstein rosenbridges.

998
00:51:31.719 --> 00:51:34.039
<v Speaker 2>Or er A geometric connection.

999
00:51:33.719 --> 00:51:37.079
<v Speaker 3>Through space The second paper, written with Podolski and Rosen,

1000
00:51:37.440 --> 00:51:42.000
<v Speaker 3>described the strange phenomenon of quantum entanglement, which Einstein famously

1001
00:51:42.079 --> 00:51:45.480
<v Speaker 3>mock as spooky action at a distance. This is the

1002
00:51:45.559 --> 00:51:47.119
<v Speaker 3>EPR paradix.

1003
00:51:46.639 --> 00:51:48.840
<v Speaker 2>Say quantum connection regardless of space.

1004
00:51:49.039 --> 00:51:52.800
<v Speaker 3>For eighty years, physics viewed these as two entirely separate phenomena,

1005
00:51:52.920 --> 00:51:55.920
<v Speaker 3>but er EPR posits that they are the exact same thing.

1006
00:51:56.440 --> 00:52:01.559
<v Speaker 3>Entangled particles are physically connected by microscopic quantum scale wormholes.

1007
00:52:01.079 --> 00:52:04.360
<v Speaker 2>So entanglement isn't just a spooky mathematical correlation, it is

1008
00:52:04.480 --> 00:52:05.960
<v Speaker 2>actual physical geometry.

1009
00:52:06.079 --> 00:52:09.559
<v Speaker 3>Yes, if two particles are highly entangled, the geometric distance

1010
00:52:09.599 --> 00:52:12.199
<v Speaker 3>between them is functionally short, regardless of where they appear

1011
00:52:12.239 --> 00:52:15.039
<v Speaker 3>to be in the classical universe. Space is literally woven

1012
00:52:15.079 --> 00:52:15.880
<v Speaker 3>out of entanglement.

1013
00:52:16.159 --> 00:52:18.960
<v Speaker 2>If we apply this to the black hole information paradox,

1014
00:52:19.039 --> 00:52:20.239
<v Speaker 2>it changes everything. YEA.

1015
00:52:20.480 --> 00:52:23.280
<v Speaker 3>If space is just a projection of a vast network

1016
00:52:23.320 --> 00:52:27.400
<v Speaker 3>of quantum entanglement, then the entire paradox is fundamentally a

1017
00:52:27.480 --> 00:52:31.440
<v Speaker 3>linguistic error. We panic because we think the information is

1018
00:52:31.519 --> 00:52:34.599
<v Speaker 3>trapped inside a distant spatial location.

1019
00:52:35.159 --> 00:52:37.880
<v Speaker 2>But if space isn't real at the lowest level, there

1020
00:52:37.960 --> 00:52:39.840
<v Speaker 2>is no inside precisely.

1021
00:52:40.400 --> 00:52:44.119
<v Speaker 3>The information isn't localized in a geometric vault. The data

1022
00:52:44.239 --> 00:52:48.599
<v Speaker 3>is simply re routing its connections through the underlying quantum network. Wow,

1023
00:52:48.920 --> 00:52:52.079
<v Speaker 3>the island extending out into deep space isn't a magical

1024
00:52:52.079 --> 00:52:54.880
<v Speaker 3>teleportation trick. It's a reflection of the fact that the

1025
00:52:54.920 --> 00:52:57.400
<v Speaker 3>interior of the black hole and the exterior radiation are

1026
00:52:57.480 --> 00:53:00.519
<v Speaker 3>highly entangled, and therefore, at the fundamental level they are

1027
00:53:00.559 --> 00:53:01.800
<v Speaker 3>geometrically adjacent.

1028
00:53:02.159 --> 00:53:06.480
<v Speaker 2>The paradox dissolves because the stage itself dissolves. The information

1029
00:53:06.599 --> 00:53:08.440
<v Speaker 2>was never lost, because it was never placed in a

1030
00:53:08.440 --> 00:53:11.800
<v Speaker 2>physical box. It remains an active node in the informational

1031
00:53:11.840 --> 00:53:12.679
<v Speaker 2>web of the universe.

1032
00:53:13.079 --> 00:53:16.480
<v Speaker 3>It is the ultimate paradigm shift. Resolving the black hole

1033
00:53:16.519 --> 00:53:20.119
<v Speaker 3>information paradox isn't just about saving an encyclopedia. It is

1034
00:53:20.199 --> 00:53:22.960
<v Speaker 3>forcing us to construct a full theory of quantum gravity,

1035
00:53:23.440 --> 00:53:27.280
<v Speaker 3>a theory where gravity, geometry, and space itself are merely

1036
00:53:27.320 --> 00:53:30.159
<v Speaker 3>the shadow cast by the interactions of quantum data.

1037
00:53:30.599 --> 00:53:33.480
<v Speaker 2>We started by looking at a dead star collapsing, but

1038
00:53:33.559 --> 00:53:36.079
<v Speaker 2>this paradox has dragged us to the absolute limits of

1039
00:53:36.159 --> 00:53:40.159
<v Speaker 2>human understanding. It proves that our current lenses general relativity

1040
00:53:40.159 --> 00:53:45.280
<v Speaker 2>and quantum mechanics are insufficient when you superimpose them, reality breaks.

1041
00:53:45.719 --> 00:53:49.679
<v Speaker 3>We need a new unified framework. Whether that framework involves

1042
00:53:49.679 --> 00:53:53.920
<v Speaker 3>holographic boundaries encoding our reality, bizarre quantum islands overlapping with

1043
00:53:53.960 --> 00:53:57.840
<v Speaker 3>deep space, or the profound realization that space time is

1044
00:53:57.840 --> 00:54:01.920
<v Speaker 3>an illusion woven from entangled data. Bit the conclusion is inescapable.

1045
00:54:02.360 --> 00:54:05.280
<v Speaker 3>The universe is fundamentally an informational system.

1046
00:54:05.599 --> 00:54:07.920
<v Speaker 2>We need to understand how the cosmos handles its most

1047
00:54:07.920 --> 00:54:10.760
<v Speaker 2>fundamental currency, and that leads to a concluding thought I

1048
00:54:10.800 --> 00:54:13.199
<v Speaker 2>want to leave you with. We've spent this time discussing

1049
00:54:13.239 --> 00:54:17.639
<v Speaker 2>reality as a projection and information as an immortal, indestructible asset.

1050
00:54:18.159 --> 00:54:20.639
<v Speaker 2>Let's take the concept of emergent space time to its

1051
00:54:20.679 --> 00:54:21.559
<v Speaker 2>logical extreme.

1052
00:54:21.800 --> 00:54:23.599
<v Speaker 3>It is a perspective altering idea.

1053
00:54:24.000 --> 00:54:28.519
<v Speaker 2>If space time and gravity are merely emergent properties generated

1054
00:54:28.559 --> 00:54:32.239
<v Speaker 2>by a deeper network of quantum entanglement, then information is

1055
00:54:32.239 --> 00:54:34.639
<v Speaker 2>not just something that exists within the universe. It isn't

1056
00:54:34.679 --> 00:54:38.760
<v Speaker 2>a book sitting on a geometric shelf. Information is the universe.

1057
00:54:39.079 --> 00:54:42.079
<v Speaker 2>The cosmos is constructed of pure data, and if that

1058
00:54:42.159 --> 00:54:45.760
<v Speaker 2>is true, then black holes which crunch that data down

1059
00:54:45.800 --> 00:54:49.599
<v Speaker 2>to its absolute extreme mathematical limits, are not the universe's

1060
00:54:49.599 --> 00:54:51.199
<v Speaker 2>garbage disposals.

1061
00:54:50.679 --> 00:54:51.119
<v Speaker 1>Not at all.

1062
00:54:51.199 --> 00:54:54.000
<v Speaker 2>Perhaps they aren't destroying reality at all. If the area

1063
00:54:54.039 --> 00:54:58.079
<v Speaker 2>of an event horizon defines the maximum storage capacity of nature,

1064
00:54:58.400 --> 00:55:01.559
<v Speaker 2>perhaps black holes are the hyper dense quantum hard drives

1065
00:55:01.599 --> 00:55:04.840
<v Speaker 2>of the cosmos, structures designed to compress and store the

1066
00:55:04.920 --> 00:55:08.039
<v Speaker 2>data of reality until a completely new understanding of physics

1067
00:55:08.079 --> 00:55:10.719
<v Speaker 2>can be booted up from them. It forces you to wonder,

1068
00:55:11.159 --> 00:55:15.039
<v Speaker 2>if the universe is ultimately a vast computational system flawlessly

1069
00:55:15.039 --> 00:55:18.719
<v Speaker 2>executing unitary operations, What exactly is the computation doing. What

1070
00:55:18.800 --> 00:55:20.719
<v Speaker 2>is the universe trying to calculate.

1071
00:55:20.239 --> 00:55:23.599
<v Speaker 3>A question that redefines the purpose of physical existence entirely?

1072
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<v Speaker 2>Something to ponder the next time you step outside, look

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<v Speaker 2>up at the seemingly simple, smooth fabric of the night sky,

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<v Speaker 2>and wonder what the true nature of the vault really

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<v Speaker 2>is