Latest / The Quark Side - Quantum Physics Podcast / Is Time Emergent? Information, Entropy, and Reality

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Is Time Emergent? Information, Entropy, and Reality · The Quark Side - Quantum Physics Podcast

0:01
Speaker 1: Welcome to the quark Side. Quantum Physics podcast, an exploration
0:05
Speaker 1: of the fundamental structure of reality, where quantum laws govern matter, energy,
0:11
Speaker 1: and information. Here, uncertainty is a feature, not a flaw,
0:16
Speaker 1: and understanding begins at the smallest scales.
0:27
Speaker 2: I want you to just stop for a second, whatever
0:29
Speaker 2: you're doing, put down the phone, just listen. If it's
0:33
Speaker 2: quiet enough, maybe you can hear a clock or I
0:37
Speaker 2: don't know the hum of your computer. But even if
0:40
Speaker 2: it's dead silent, you feel it, don't you.
0:42
Speaker 3: Oh? Absolutely, that constant forward motion.
0:45
Speaker 2: Yeah, that relentless push. A second passes, then another. You
0:50
Speaker 2: can remember the coffee you had this morning, right, the taste,
0:52
Speaker 2: the warmth, but you can't remember the dinner you're going
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Speaker 2: to have tonight.
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Speaker 3: It's maybe the most fundamental part of being human. We're born,
1:01
Speaker 3: we age, it's one way street. It feels absolutely it
1:03
Speaker 3: feels like the bedrock of reality. Like if you took
1:06
Speaker 3: everything else so at, all the matter, all the energy, gravity, everything,
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Speaker 3: you still feel like time would be there, just ticking away.
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Speaker 2: In the dark, waiting for something to happen. Yeah.
1:15
Speaker 3: But yeah, and this is the idea that has been
1:17
Speaker 3: just completely messing with my head. For the past few days.
1:21
Speaker 3: What if that feeling is an illusion?
1:24
Speaker 2: Illusion is a strong word, maybe a secondary effect, a
1:28
Speaker 2: byproduct of something much much deeper. We've been going through
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Speaker 2: some really fascinating, really dense material about what some are
1:36
Speaker 2: calling a quiet revolution in physics, and the headline claim
1:41
Speaker 2: is just staggering. Time is not fundamental, right.
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Speaker 3: It's not the foundation. The proposal is that time is
1:48
Speaker 3: actually emerging from something.
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Speaker 2: Else entirely, and that something else is information.
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Speaker 3: Something we usually think of as abstract, you know, bits
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Speaker 3: and bites, but physicists are starting to treat it as
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Speaker 3: a real physical thing.
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Speaker 2: The argument, if we hading it right, is that the
2:02
Speaker 2: universe is basically a giant recording device.
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Speaker 3: In a manner of speaking, yes, and what we call
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Speaker 3: time is just the act of that device recording, writing
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Speaker 3: things into its own memory.
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Speaker 2: Okay, we've got to unpack this very carefully, because time
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Speaker 2: is memory. Sounds it sounds like.
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Speaker 3: Poetry, it does, but the physics behind it is pretty serious.
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Speaker 2: I want to start with the problem itself because I
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Speaker 2: think most of us, myself included, kind of assume science
2:28
Speaker 2: has time figured out. We've got atomic clocks, GPS, we're
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Speaker 2: pretty good at knowing what time it is.
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Speaker 3: We know how to measure it. That's a very different
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Speaker 3: thing from knowing what it is. And honestly, for over
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Speaker 3: a century, physics has been well embarrassed.
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Speaker 2: By n Rist. That's not a word I associate with physics.
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Speaker 3: It's the only word that really fits. Because you see,
2:48
Speaker 3: we have two grand theories of the universe, two main
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Speaker 3: rule books. On one side, you've got Aubert Einstein general relativity.
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Speaker 2: The big stuff, planets, stars, galaxy, these gravity, the cosmic
3:01
Speaker 2: scale exactly.
3:03
Speaker 3: And in Einstein's world, time is not some universal clock
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Speaker 3: taking the same for everyone. It's dynamic.
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Speaker 2: It's a lack of into space right space.
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Speaker 3: Time fabric, and it stretches and it squeezes. If you
3:15
Speaker 3: fly really fast in a spaceship, your clock takes slower
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Speaker 3: than mine back here on Earth. If you hang out
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Speaker 3: near a black hole, your.
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Speaker 2: Clock slows to a crawl. The twin paradox precisely.
3:24
Speaker 3: So time is relative. It's a coordinate like left, right,
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Speaker 3: er up down, but it's a bendi one. It's part
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Speaker 3: of the geometry of the universe.
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Speaker 2: Okay, so that's Rule book one. Time is a flexible
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Speaker 2: personal dimension. What about Rule book two?
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Speaker 3: Rule Book two is quantum mechanics, the laws for the
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Speaker 3: very very small atoms, electrons, photons, all the tiny particles
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Speaker 3: that make up you and me and everything else.
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Speaker 2: And what does it say about time?
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Speaker 3: It says the exact opposite. In standard quantum mechanics, time
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Speaker 3: is rigid. It's absolute. How so, it's what physicists call
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Speaker 3: an external parameter. Think of it like a metronome sitting
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Speaker 3: outside the experiment, ticks away TikTok at a steady universal pace.
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Speaker 2: And it doesn't care what the particles are doing.
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Speaker 3: Not at all. It's a rigid background stage. The particles
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Speaker 3: can dance and interact and do all their quantum weirdness,
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Speaker 3: but the stage itself, the clock, is completely unaffected. It's
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Speaker 3: just there.
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Speaker 2: So Einstein says time is a participant in the dance.
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Speaker 2: Quantum mechanics says it's the unchanging stage. The dance happens on.
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Speaker 3: You've nailed it. That is the fundamental conflict, and it works.
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Speaker 3: You know, it's fine as long as you keep them separate.
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Speaker 3: You use Einstein for the cosmos, you use quantum mechanics
4:31
Speaker 3: for your phone's processor.
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Speaker 2: But the universe doesn't keep them separate. The Big Bang
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Speaker 2: was both incredibly massive and incredibly small.
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Speaker 3: Exactly. The ultimate goal of physics, the holy grail, is
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Speaker 3: to unite them a single theory that explains everything quantum gravity.
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Speaker 2: And I'm guessing that when you try to write the
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Speaker 2: equations for that time becomes the big problem.
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Speaker 3: It becomes the problem when you try to merge the
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Speaker 3: math of these two frameworks the equations, well, they break,
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Speaker 3: and they break in a very specific and terrifying way.
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Speaker 2: This is where that Wheeler DeWitt equation comes in, right.
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Speaker 2: The source material really focused on this.
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Speaker 3: It's the classic example. Back in the nineteen sixties, John
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Speaker 3: Wheeler and Bryce DeWitt tried to write a single equation
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Speaker 3: that describes the quantum state of the entire universe. They
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Speaker 3: took Einstein's ideas about geometry and smashed them together with
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Speaker 3: the rules of quantum mechanics. And what happened when they
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Speaker 3: work through the math. When they simplified the equation the
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Speaker 3: variable for time, the letter t yeah, it vanished.
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Speaker 2: It is weird. It completely canceled out. The final equation
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Speaker 2: basically says that the rate of change of the universe
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Speaker 2: is zero.
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Speaker 3: Wait wait, an equation to describe all of reality and
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Speaker 3: the result is nothing ever happens. That's it. It describes
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Speaker 3: a static, frozen universe, a block. It contains every possible
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Speaker 3: arrangement of everything all at once, but there's no flow
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Speaker 3: from one moment to the next.
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Speaker 2: That's what they call the problem of time.
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Speaker 3: That is the crisis. Our best attempt at a fundamental
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Speaker 3: equation says change is an illusion. But we look around
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Speaker 3: and my coffee is getting cold. Things are obviously changing.
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Speaker 2: So the math is just wrong that right, I mean,
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Speaker 2: how can you trust an equation that says I'm not
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Speaker 2: getting older?
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Speaker 3: And that is the terrifying part. We don't think the
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Speaker 3: math is wrong individually. General relativity and quantum mechanics are
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Speaker 3: the most precisely tested theories in the history of science.
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Speaker 3: They work perfectly. It's only when they're combined that time
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Speaker 3: goes away.
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Speaker 2: So either our perception of time is a profound illusion, or.
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Speaker 3: We are missing something fundamental about how time is generated.
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Speaker 2: Which brings us to the let's call it the classic explanation.
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Speaker 2: But what I learned in school, the bandage that physics
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Speaker 2: has used for a century to explain the.
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Speaker 3: Flow of time, entropy, the arrow of time.
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Speaker 2: Right, the second law of thermodynamics can you just refresh
6:47
Speaker 2: us on that the shattered glass idea.
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Speaker 3: Of course, the second law says that in an isolated system,
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Speaker 3: disorder or entropy tends to increase.
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Speaker 2: Over time, things get messier.
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Speaker 3: Things get messier. If you drop a pristine ordered coffee mug,
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Speaker 3: it shatters into a disordered pile of one hundred pieces.
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Speaker 3: You will never ever see those hundred pieces spontaneously leap
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Speaker 3: off the floor and reassemble themselves back into a perfect mug, because.
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Speaker 2: There's only one way to be a perfect mug, but
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Speaker 2: a billion ways to be a pile of broken shards.
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Speaker 3: Precisely, the universe moves from unlikely ordered states to much
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Speaker 3: more probable disordered states, and we just label that direction
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Speaker 3: of increasing messinesses forward in time.
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Speaker 2: This has always felt pretty intuitive to me. My desk
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Speaker 2: gets cluttered, not cleaner. So if entropy explains the era
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Speaker 2: of time, why are we even having this conversation? Why
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Speaker 2: is this new information idea even necessary?
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Speaker 3: Because entropy is more of a description of what happens,
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Speaker 3: not a fundamental explanation for why time exists. And the
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Speaker 3: source material points out two massive holes in the argument.
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Speaker 2: Okay, what was the first one?
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Speaker 3: The first is that the fundamental laws of physics themselves
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Speaker 3: don't have a preferred direction in time. They are as
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Speaker 3: we say, time symmetric.
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Speaker 2: Meaning they work just as well forwards as they do backwards.
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Speaker 3: Exactly, if you watch a video of two billiard balls colliding,
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Speaker 3: you can't tell if I'm playing it forwards or in reverse.
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Speaker 3: The physics is identical Schrodinger's equation Newton's laws. They don't
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Speaker 3: care about past or future.
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Speaker 2: So if the basic rules for the atoms don't have
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Speaker 2: an arrow of time, how can the mug made of
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Speaker 2: those atoms have one.
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Speaker 3: You can't build a one way street out of two
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Speaker 3: way birds. It feels like you're smuggling the conclusion in somewhere.
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Speaker 2: Okay, that's a big hole. What's the second one?
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Speaker 3: The second one is even bigger. It's called the past hypothesis.
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Speaker 3: For the whole entropy argument to work, for the universe
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Speaker 3: to be getting messier now, it must have started in
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Speaker 3: a state of absurdly, unbelievably low entropy.
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Speaker 2: The Big Bang had to be perfectly neat and tidy.
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Speaker 3: Incredibly tidy, and statistically that's just bizarre. It's like walking
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Speaker 3: down the beach and finding a billion grains of sand
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Speaker 3: all lined up in a perfect row. You wouldn't think
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Speaker 3: it just happened by chance.
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Speaker 2: You'd assume someone or something set it.
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Speaker 3: Up that way, right, But the entropy theory just says, well,
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Speaker 3: it started out tidy. It doesn't explain why it relies
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Speaker 3: on this one in a trillion initial condition as a given.
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Speaker 3: It feels like a cheat.
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Speaker 2: So to sum up the problem, our deepest math says
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Speaker 2: time doesn't exist, and our best explanation for it relies
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Speaker 2: on a cosmic coincidence that we can't explain.
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Speaker 3: We need something deeper, and that's where this quiet revolution begins,
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Speaker 3: the shift away from just thinking about matter and energy
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Speaker 3: and towards thinking about information.
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Speaker 2: This is where things really took a turn for me
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Speaker 2: in the reading. We need to be very clear about
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Speaker 2: what we mean by information, because normally I think of
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Speaker 2: it as data, the words on a page. It's abstract,
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Speaker 2: it feels abstract.
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Speaker 3: But the sources we're looking at treat information as a
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Speaker 3: physical quantity, as real as.
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Speaker 2: A rock or a beam of light, as real as mass, not.
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Speaker 3: Just as real in some sense equivalent to mass and energy.
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Speaker 2: Hey, you got to explain that I can put a
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Speaker 2: rock on a scale I can't weigh an idea.
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Speaker 3: Well, this goes back to the nineteen sixties to a
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Speaker 3: physicist at IBM named Ralph Landauer. He established a fundamental
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Speaker 3: rule called Landauer's principle, and it's what connects the abstract
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Speaker 3: world of bits and bytes to the physical world of thermodynamics.
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Speaker 2: Is this related to that old thought experiment, Maxwell's Demon?
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Speaker 3: It's the solution to Maxwell's demon.
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Speaker 2: Yes.
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Speaker 3: The demon was this imaginary creature that could sort hot
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Speaker 3: and cold molecules, seemingly, violating the second law of thermodynamics
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Speaker 3: by creating order from chaos.
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Speaker 2: Right, it could make one side of a box hot
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Speaker 2: and the other cold for free, seemingly.
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Speaker 3: But Landauer realized the demon has to know which molecules
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Speaker 3: are which it has to measure them. It has to
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Speaker 3: store that information, even for a moment, and then to
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Speaker 3: keep sorting, it has to forget the previous measurement to
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Speaker 3: make room for the next one.
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Speaker 2: So forgetting costs something.
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Speaker 3: Erasing information has a physical cost. That was Landauer's great insight.
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Speaker 3: He proved that to irreversibly erase one bit of information
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Speaker 3: to resettle one to a zero, you must dissipate a
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Speaker 3: tiny but non zero amount of heat into the environment.
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Speaker 2: So deleting a file on my computer actually generated the
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Speaker 2: tiny puff of.
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Speaker 3: Heat, a truly infinitesimal amount. But yes, deletion is heat,
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Speaker 3: and heat is a form of energy. We know from
11:08
Speaker 3: Einstein's famous equation E equals mc squared that energy and
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Speaker 3: mass are two sides of the same coin.
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Speaker 2: So information is tied to energy, which is tied to mass.
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Speaker 3: It's physically tethered to the world. It's not a ghost
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Speaker 3: in the machine. In a very real sense, it is
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Speaker 3: part of the machine.
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Speaker 2: Let me see if I've got this. If I have
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Speaker 2: two identical hard drives and I fill one up with
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Speaker 2: a complex movie and leave the other one blank, does
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Speaker 2: the full one technically weigh more.
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Speaker 3: In principle, yes, the difference would be smaller than the
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Speaker 3: way of a single atom, But it is not zero.
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Speaker 3: A drive full of complex high entropy data contains more
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Speaker 3: energy than a formatted drive of all zeros.
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Speaker 2: Okay, that grounds it for me. It's real, and this
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Speaker 2: reality of information is where the new theory of time
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Speaker 2: comes from.
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Speaker 3: It's the key because once you accept that information is physical,
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Speaker 3: you collide head on with the biggest puzzle in modern physics,
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Speaker 3: the black hole. Information paradox.
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Speaker 2: It always comes back to black holes, doesn't it.
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Speaker 3: They're the ultimate laboratory there where gravity and quantum mechanics
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Speaker 3: are both pushed to their absolute limits.
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Speaker 2: So Stephen Honking he figured out that black holes aren't
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Speaker 2: actually black.
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Speaker 3: They leak, they radiate, they glow with what we now
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Speaker 3: call Hawking radiation, and over immense time scales, they can
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Speaker 3: completely evaporate and disappear.
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Speaker 2: And this created a problem.
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Speaker 3: A universe sized problem. Imagine you take a library of books,
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Speaker 3: all that information, all those stories, and you dump it
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Speaker 3: into a black hole. That information is now inside, but then,
12:37
Speaker 3: over trillions of years, the black hole evaporates into nothing
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Speaker 3: but random thermal radiation.
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Speaker 2: Where did the information in the books go?
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Speaker 3: Exactly? If the black hole is gone and all that's
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Speaker 3: left is random heat, the information seems to have been
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Speaker 3: deleted from the universe, and that's not allowed. It's a
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Speaker 3: cardinal sin. In quantum mechanics, there's a strict law called unitarity,
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Speaker 3: which says that information can never ever be truly destroyed.
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Speaker 3: You can scramble it, you can hide it, but you
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Speaker 3: should always, in principle, be able to piece it back together.
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Speaker 3: A black hole that deletes information breaks quantum mechanics.
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Speaker 2: So who won hawking or quantum mechanics.
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Speaker 3: In the end, almost everyone agrees that quantum mechanics has
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Speaker 3: to win. The information must be preserved, It has to
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Speaker 3: somehow be encoded in the radiation that leaks out.
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Speaker 2: And this whole fight forced physicists to take information seriously.
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Speaker 3: It forced them to see information not as something that
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Speaker 3: describes reality, but as a fundamental ingredient of reality, maybe
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Speaker 3: even more fundamental than space and time themselves.
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Speaker 2: Okay, so let's make the pivot. If information is the
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Speaker 2: real bedrock, how do you build what we feel as
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Speaker 2: time on top of that foundation.
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Speaker 3: This is the heart of the new model. The idea
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Speaker 3: is to stop thinking of space time as a smooth, empty.
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Speaker 2: Stage, an empty container. Right.
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Speaker 3: Instead, you have to start thinking of it as a
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Speaker 3: storage medium, a physical substrate like a cosmic card drivegy.
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Speaker 3: The source material uses the idea of a space time
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Speaker 3: lattice or spacetime cells. Imagine space isn't continuous. Imagine it's
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Speaker 3: made of tiny, fundamental, discrete units pixels of reality.
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Speaker 2: Okay, I'm with you.
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Speaker 3: And these cells aren't just empty placeholders. They have a job.
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Speaker 3: Their job is to record record what interactions every time
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Speaker 3: two particles collide, every time a photon of light brounces
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Speaker 3: off an electron, that's an event. The theory proposes that
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Speaker 3: these events leave a physical mark, a trace, an imprint
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Speaker 3: on the structure of the space time cells themselves.
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Speaker 2: So the fabric of the universe is keeping a log book.
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Speaker 3: It is the logbook. This is the crucial shift. The
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Speaker 3: universe doesn't exist in time. It generates time by writing
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Speaker 3: its own history into its own structure.
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Speaker 2: I love that image, but what does it mean mechanically?
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Speaker 2: How does writing a logbook create this feeling of a
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Speaker 2: second passing and then another.
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Speaker 3: It comes down to irreversibility. Think about the difference between
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Speaker 3: the past and the future. In this moment. The past
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Speaker 3: is what has already been written down. The future is
15:03
Speaker 3: the blank part.
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Speaker 2: Of the page.
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Speaker 3: Now, the key assumption is that you can't erase the ink.
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Speaker 3: Once an interaction happens, the information about it, the entanglement,
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Speaker 3: the correlations, leaks out and gets imprinted on the environment.
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Speaker 3: On this space time lattice.
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Speaker 2: You can't put the genie back in the bottle.
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Speaker 3: You can't globally unwrite an event, and because of that,
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Speaker 3: the record can only grow.
15:23
Speaker 2: The file size only gets bigger.
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Speaker 3: Precisely, the arrow of time in this view isn't about
15:29
Speaker 3: entropy or things getting messy. It's about the amount of
15:33
Speaker 3: information in the universe increasing. We experience time moving forward
15:39
Speaker 3: for one simple reason. There's more information in the universe
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Speaker 3: now than there was a nanosecond ago.
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Speaker 2: So the present moment is just the leading edge of
15:48
Speaker 2: the recording head laying down a new track.
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Speaker 3: That's a perfect way to put it. And this completely
15:53
Speaker 3: reframes our place in the cosmos. We aren't just passengers
15:56
Speaker 3: on a river of time that was already flowing.
15:58
Speaker 2: We're making the river.
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Speaker 3: Flow our existence. Every single interaction between particles is what
16:03
Speaker 3: carves the channel. We are actively constructing space time by
16:07
Speaker 3: living in it.
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Speaker 2: You just said something that I want to pause on
16:11
Speaker 2: constructing space time. Does this recording process actually change the
16:15
Speaker 2: physical geometry of space?
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Speaker 3: According to the theory, Yes, And this is where it
16:19
Speaker 3: gets really exciting because it might just solve one of
16:21
Speaker 3: the biggest mysteries in astronomy dark matter. Dark matter.
16:24
Speaker 2: Okay, let's set the scene for this because it's a
16:25
Speaker 2: huge claim. The standard story of dark matter is that
16:29
Speaker 2: our galaxies are spinning too fast.
16:31
Speaker 3: Right, It's a simple observation. You look at a spiral galaxy,
16:35
Speaker 3: you measure the speed of the stars. You expect the
16:38
Speaker 3: stars on the outer edge to be moving much slower
16:40
Speaker 3: than the ones near the center, because gravity gets weaker
16:43
Speaker 3: with distance, just.
16:44
Speaker 2: Like in our solar system, Pluto moves way slower than Mercury.
16:48
Speaker 3: But that is not what we see when we look
16:51
Speaker 3: at galaxies. The rotation curve is flat. The stars on
16:55
Speaker 3: the very edge are whipping around almost as fast as
16:58
Speaker 3: the stars in.
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Speaker 2: The middle, going so fast they should just fly off
17:01
Speaker 2: into space.
17:02
Speaker 3: They should be flung out. The gravity from all the
17:05
Speaker 3: stars in gas we can see isn't nearly strong enough
17:07
Speaker 3: to hold them in orbit. So for decades astronomers have
17:10
Speaker 3: assumed there must be some extra invisible stuff providing the
17:14
Speaker 3: extra gravitational glue.
17:15
Speaker 2: An invisible halo of dark matter.
17:17
Speaker 3: A mysterious particle that doesn't interact with light, that we
17:20
Speaker 3: can't see, but that has a lot of gravity. And
17:23
Speaker 3: we've spent half a century and billions or dollars building
17:26
Speaker 3: incredibly sensitive detectors deep underground trying to catch one of.
17:30
Speaker 2: These particles, and the result has been nothing.
17:33
Speaker 3: A complete blank, not a single confirmed detection.
17:37
Speaker 2: So how does this time is memory idea solve the
17:41
Speaker 2: problem without inventing a new particle.
17:43
Speaker 3: It offers a truly radical alternative. It says you don't
17:46
Speaker 3: need invisible matter. The extra gravity isn't coming from stuff,
17:50
Speaker 3: It's coming from the space time fabric itself.
17:53
Speaker 2: Wow.
17:53
Speaker 3: Remember Landauer's principle, information has an energy equivalent, and energy
17:58
Speaker 3: curves space time. That's just general relativity. Okay, So if
18:02
Speaker 3: space time is recording the history of interactions, then a
18:06
Speaker 3: region of space that has a lot of history, like
18:08
Speaker 3: a galaxy which has been around for billions of years,
18:12
Speaker 3: with stars forming and exploding and gas clouds colliding, is
18:15
Speaker 3: saturated with these records. It's heavy with information.
18:19
Speaker 2: The memory of the galaxy gives it extra mass.
18:21
Speaker 3: It creates an effective gravitational pull. The space time in
18:25
Speaker 3: and around a galaxy is different from the space time
18:27
Speaker 3: and the empty void between galaxies. It's been altered by
18:30
Speaker 3: its own past.
18:32
Speaker 2: So the stars on the edge are orbiting so fast
18:35
Speaker 2: not because of an invisible cloud of particles, but because
18:37
Speaker 2: they're moving through a space time that is dense with
18:40
Speaker 2: the memory of everything that happened before.
18:42
Speaker 3: That's the proposal. It's not ghost matter holding the galaxy together.
18:46
Speaker 3: It's the galaxy's own history that.
18:48
Speaker 2: Is profoundly elegant. It ties the quantum world of information
18:52
Speaker 2: directly to the cosmic scale of galaxies.
18:55
Speaker 3: It suggests that the arrow of time and the mystery
18:58
Speaker 3: of dark matter might not be too so problems. They
19:01
Speaker 3: could be two symptoms of the exact same underlying process,
19:05
Speaker 3: the universe accumulating a record of its own existence.
19:08
Speaker 2: I have to be the skeptic here, though it's a
19:10
Speaker 2: beautiful story. It ties up loose ends. But is it
19:13
Speaker 2: science or is it just a nice philosophy? Can you
19:16
Speaker 2: test it?
19:17
Speaker 3: That's the most important question, and the answer is yes.
19:19
Speaker 3: Unlike a lot of other ideas in quantum gravity, this
19:22
Speaker 3: one makes concrete, falsifiable predictions.
19:25
Speaker 2: Okay, how do you test if the universe is a
19:27
Speaker 2: hard drive?
19:28
Speaker 3: One place to look is again black holes in the
19:31
Speaker 3: standard picture. The Hawking radiation they emit is purely thermal.
19:35
Speaker 3: It's random. It's basically just heat, like the glow from
19:37
Speaker 3: a hot piece of coal, just noise exactly. But if
19:41
Speaker 3: this information theory is correct, and the information of things
19:43
Speaker 3: that fell in must be preserved, then that radiation can't
19:46
Speaker 3: be perfectly random.
19:47
Speaker 2: There has to be a signal hidden in the noise.
19:50
Speaker 3: There should be subtle correlations, patterns, a kind of structure
19:54
Speaker 3: hidden in the radiation that encodes the history of the
19:56
Speaker 3: black hole.
19:57
Speaker 2: Can we see that?
19:58
Speaker 3: Not yet. We need telescopes with far greater sensitivity than
20:02
Speaker 3: anything we have today. But it's a clear prediction. The
20:06
Speaker 3: theory says hawking radiation has structure. The old theory says
20:09
Speaker 3: it doesn't. One day we'll be able to look and
20:12
Speaker 3: see who's right.
20:12
Speaker 2: So that's a test for the future. Is there anything
20:15
Speaker 2: we can do now?
20:16
Speaker 3: There is.
20:17
Speaker 2: We can test it in the lab, on a tabletop.
20:20
Speaker 3: On a microchip using quantum computers.
20:22
Speaker 2: Ah.
20:23
Speaker 3: Of course, researchers can use quibits, the quantum equivalent of
20:26
Speaker 3: computer bits, to build tiny simulated universes. They can program
20:31
Speaker 3: a handful of these quibits to interact according to quantum rules.
20:35
Speaker 2: They create spacetime cells on a chip.
20:38
Speaker 3: Essentially, yes, and they can set up these systems to
20:41
Speaker 3: be perfectly reversible. In theory, you should be able to
20:44
Speaker 3: run the whole process backwards without any issue. There should
20:47
Speaker 3: be no inherent earrow of time.
20:49
Speaker 2: But what do they find.
20:50
Speaker 3: They find that as soon as the quibits interact the
20:52
Speaker 3: information about that interaction starts to spread out through the system,
20:56
Speaker 3: and this process of information spreading out of become correlated
21:00
Speaker 3: with the wider environment, creates an effective arrow of time.
21:05
Speaker 2: Even though the underlying laws are reversible.
21:08
Speaker 3: Yes, they can literally watch informational time emerge from the
21:12
Speaker 3: system's own processing. It shows on a small scale that
21:16
Speaker 3: you don't need a master clock to have time. You
21:19
Speaker 3: just need a system that records and spreads information.
21:23
Speaker 2: That is that's incredible. It's like building a little toy
21:25
Speaker 2: universe that learns to have it passed in a future
21:28
Speaker 2: all by itself.
21:28
Speaker 3: It's powerful evidence for the core mechanism of the theory.
21:32
Speaker 2: This whole thing is such a monumental shift in perspective.
21:35
Speaker 2: We tend to think of the laws of physics as
21:37
Speaker 2: being imposed on the universe from the outside, you know,
21:40
Speaker 2: like a cosmic rule book that was written before the
21:42
Speaker 2: game started.
21:43
Speaker 3: The platonic view of laws.
21:44
Speaker 2: Yes, but this theory suggests the rules, or at least
21:47
Speaker 2: some of them, like time and gravity, are actually emerging
21:50
Speaker 2: from the game as it's being played.
21:52
Speaker 3: That's a great way to describe it. It's the difference
21:55
Speaker 3: between a scripted play and an improv show. In the
21:58
Speaker 3: old block universe view, this script is already written, past, present, future,
22:02
Speaker 3: all there. We just read our lines.
22:04
Speaker 2: In this view, there is no script.
22:06
Speaker 3: There is no script. We are writing it line by
22:09
Speaker 3: line with every interaction, and once a line is spoken,
22:12
Speaker 3: it's part of the permanent record.
22:14
Speaker 2: It's canon, which leads me to something that's been bothering me.
22:17
Speaker 2: If the universe remembers everything, if every single thing that
22:21
Speaker 2: happens is etched into the geometry of space, does anything
22:25
Speaker 2: ever truly get lost?
22:27
Speaker 3: That's the deepest philosophical implication of this entire framework. In
22:31
Speaker 3: a universe where time is the accumulation of information, the
22:34
Speaker 3: concept of gone doesn't really mean anything.
22:37
Speaker 2: We think of the past as being gone. It's over.
22:39
Speaker 2: It exists in my memory, sure, but it's not physically
22:42
Speaker 2: here anymore.
22:42
Speaker 3: But if this theory is correct, that's wrong. The past
22:46
Speaker 3: is physically present. It's encoded in the current structure of
22:49
Speaker 3: the universe. The configuration of everything right now is the
22:52
Speaker 3: complete record of its history.
22:54
Speaker 2: So our lives aren't just a fleeting sequence of events.
22:59
Speaker 2: There are permanent con contribution to the structure of reality.
23:02
Speaker 3: You're not just passing through the universe, you are actively
23:05
Speaker 3: building it. Every choice you make, every word you say,
23:08
Speaker 3: every breath you take is adding a new, permanent piece
23:12
Speaker 3: of information to the cosmos. You are quite literally making
23:16
Speaker 3: the universe heavier with meaning.
23:18
Speaker 2: Let me bring it back to the beginning for a moment,
23:20
Speaker 2: the frozen universe from the Wheeler to Wit equation. Does
23:24
Speaker 2: this new theory solve that? Does it explain why we
23:27
Speaker 2: perceive flow if the fundamental equation is static?
23:30
Speaker 3: It does? It reconciles the two views from a god's
23:32
Speaker 3: eye perspective. Outside of everything, the universe might well be
23:35
Speaker 3: a single, static, four dimensional block of information, timeless.
23:40
Speaker 2: The frozen block still exists.
23:41
Speaker 3: But inside that block, for any observer living within it,
23:44
Speaker 3: the information is not distributed evenly. There's a gradient. The
23:48
Speaker 3: structure itself contains a sequence. It flows from states of
23:51
Speaker 3: less information the beginning to states of more information.
23:54
Speaker 2: So the block is static, but the pattern written on
23:57
Speaker 2: the block creates the appearance of a movie playing exactly.
24:01
Speaker 3: Time is the gradient of information, just like a hill
24:03
Speaker 3: is a gradient of elevation. The flow of time is
24:07
Speaker 3: just us experiencing that change from less complexity to more complexity.
24:11
Speaker 2: It really is a thermodynamics of time.
24:13
Speaker 3: Then that's the term for it in the same way
24:15
Speaker 3: that temperature isn't a fundamental property of a single atom,
24:19
Speaker 3: it's an average property of many atoms. Time isn't a
24:22
Speaker 3: fundamental property of the universe at the smallest scale. It's
24:26
Speaker 3: an emergent statistical property of information.
24:29
Speaker 2: So if I could zoom in all the way down
24:30
Speaker 2: to those space time cells, I wouldn't see a tiny
24:33
Speaker 2: clock ticking.
24:34
Speaker 3: No, you would just see a network of connections, a
24:36
Speaker 3: web of information. Time is the shadow cast by the
24:39
Speaker 3: processing happening on that web.
24:41
Speaker 2: What does this due to ideas like time travel? Because
24:44
Speaker 2: if time is just another dimension, sci Fi loves to
24:47
Speaker 2: talk about flying backwards along.
24:48
Speaker 3: It, Well, what makes time travel to the past profoundly difficult,
24:51
Speaker 3: if not logically impossible?
24:53
Speaker 2: So no going back to fix mystrakes.
24:55
Speaker 3: Think about it. If time is just a road, maybe
24:58
Speaker 3: you can turn your car around. But if time is
25:00
Speaker 3: the irreversible accumulation of a cosmic record, you can't go back.
25:04
Speaker 3: Why not to go back to yesterday? You would have
25:07
Speaker 3: to find a way to erase today's information from every
25:11
Speaker 3: single particle in the universe that it has touched. You'd
25:14
Speaker 3: have to undo every single quantum record that has been made.
25:18
Speaker 2: You would be fighting against the fundamental tendency of the
25:21
Speaker 2: universe to record things.
25:23
Speaker 3: You'd be fighting unitarity. You'd be fighting the second law
25:26
Speaker 3: of thermodynamics. On a cosmic scale. The past is locked
25:29
Speaker 3: because it's already been written. The future is open because
25:32
Speaker 3: the page is still blank.
25:34
Speaker 2: That at least feels right. It secures the past. You
25:36
Speaker 2: can't go back and create a paradox by killing your
25:40
Speaker 2: own grandfather.
25:41
Speaker 3: Because the information that your grandfather lived is already a
25:45
Speaker 3: structural component of the universe you inhabit. It's part of
25:48
Speaker 3: the geometry you're standing on.
25:50
Speaker 2: So we lose the DeLorean, but we get a universe
25:54
Speaker 2: that remembers us and an explanation for dark matter without
25:57
Speaker 2: needing magic particles.
25:59
Speaker 3: I call that a pretty good train. It's a much
26:00
Speaker 3: more elegant picture of the cosmos.
26:02
Speaker 2: Let's try to sum this all up. It's been a
26:04
Speaker 2: lot to process.
26:05
Speaker 3: It has okay, the big picture one. Our two best
26:09
Speaker 3: theories of physics, relativity and quantum mechanics, clash over the
26:13
Speaker 3: nature of time, leading to the problem of time where
26:16
Speaker 3: it vanishes from the math two.
26:18
Speaker 2: The old solution entropy explains the era of time as
26:22
Speaker 2: increasing disorder, but it has to assume the universe started
26:25
Speaker 2: in a bizarrely tidy state for no reason.
26:27
Speaker 3: Three, the new solution proposes that information is physical and
26:31
Speaker 3: that space time itself is a memory system that records
26:34
Speaker 3: every interaction that ever happens.
26:36
Speaker 2: Four, Time is the process of that record growing. The
26:39
Speaker 2: flow we feel is just the universe's memory getting larger
26:42
Speaker 2: and more complex.
26:43
Speaker 3: And five, this process of information accumulation actually has a
26:47
Speaker 3: gravitational effect, which might explain the mystery of dark matter
26:50
Speaker 3: without needing any new particles.
26:51
Speaker 2: And the big takeaway for us living.
26:53
Speaker 3: In it, we need to move from thinking about the
26:55
Speaker 3: universe as a passive stage for events to seeing it
26:58
Speaker 3: as an active system that is constant learning and remembering.
27:01
Speaker 3: It's a participant in its own story.
27:04
Speaker 2: You know, when we started, we talked about that gut
27:06
Speaker 2: feeling of time, and usually when physics comes along and
27:10
Speaker 2: explain something, it could feel like it's taking the magic away.
27:13
Speaker 2: You know, a rainbow is just light refraction. Love is
27:16
Speaker 2: just chemicals.
27:17
Speaker 3: It often feels reductive.
27:18
Speaker 2: Yes, but this, yes, this doesn't feel reductive to me.
27:21
Speaker 2: Time is memory. It feels significant. It feels like it
27:26
Speaker 2: gives a cosmic weight to our experience. It validates that
27:30
Speaker 2: feeling that the past isn't just gone, that it matters.
27:33
Speaker 3: It's built into the very foundation of the present. I agree,
27:36
Speaker 3: it gives a literal weight to history.
27:38
Speaker 2: So before we wrap up, I want to leave you
27:40
Speaker 2: with one last question to think about.
27:41
Speaker 3: Let's hear it.
27:42
Speaker 2: Okay, So the universe is a recording device. It's a
27:46
Speaker 2: library at everything that has ever happened written into the
27:49
Speaker 2: geometry of space. My question is who's reading it? That
27:53
Speaker 2: is the question? Isn't it is the writing of the
27:55
Speaker 2: book the whole point? Or is there a reader? And
27:59
Speaker 2: if the rec can never be fully raced, if every
28:02
Speaker 2: moment is permanently stored, does that mean, in a very
28:05
Speaker 2: real physical sense, that nothing ever truly ends, that were
28:10
Speaker 2: all just permanent features like mountains rivers on the landscape
28:13
Speaker 2: of space time.
28:14
Speaker 3: If the theory holds, the answer would have to be yes.
28:18
Speaker 3: Your existence is a permanent scar on the geometry of reality.
28:22
Speaker 2: Wow, I think I'm going to walk a little more
28:24
Speaker 2: deliberately today. I'm literally carving my path into the universe.
28:27
Speaker 3: Make it a good one.