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Speaker 1: So right now, the solar system looks like this perfectly

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ticking clock.

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Speaker 2: Yeah, it really like you.

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Speaker 1: Walk outside on a clear night, you look up and

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everything just seems completely fixed. It seems permanent, right, balanced,

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exactly perfectly balanced. But hidden in the really complex math

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of gravity is this one percent chance that mercury will

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just go completely rogue, which is terrifying, right, it could

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cross the orbit of Venus and literally smash the inner

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planets into dust. Yeah, and I mean this could happen

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long before our sun even begins to die.

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Speaker 2: Yeah, that's the crazy part.

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Speaker 1: So that clockwork predictability that you see when you look

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up it is, well, it's a temporary statistical illusion. Welcome

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to thrilling Threads.

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Speaker 2: It's great to be here for this one today.

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Speaker 1: Our mission is to just completely unpack the chronological, scientifically

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inevitable unraveling of our solar system and actually the entire universe.

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Speaker 2: And we are not just talking about, you know what happens.

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We're going to look under the hood at exactly why

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it happens. Because if there's a central theme to this

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entire journey we're taking you on today, a single unifying

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force driving every single stage of this cosmic unraveling. It

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is gravity, always, gravity always. Gravity is the ultimate engine

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of both creation and destruction every phase of our universe's life,

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from the ignition of the very first stars to like

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the chaotic planetary billiards we'll talk about, all the way

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down to the final black holes. Well, it's essentially a

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story of gravity relentlessly trying to.

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Speaker 1: Crush matter, and the universe just slowly running out of

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ways to push back against it.

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Speaker 2: Exactly. It's a losing battle.

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Speaker 1: I love that framing, like gravity is this relentless, unavoidable crush,

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and we are diving deep into the actual physics of

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this today, drawing on literally centuries of astrophysical data.

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Speaker 2: It's really fascinating sources.

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Speaker 1: Yeah, spanning from the seventeen hundreds all the way to

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recent supercomputer simulations. But we want to be really clear

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right off the bat, yes, absolutely understanding this timeline. It

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doesn't make our current lives meaningless, right, I think it

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does the opposite, oh for sure.

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Speaker 2: Like actually seeing the violent, chaotic mechanisms that dictate the

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future makes the fact that you and I are here

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right now having this conversation. It feels like a mathematical miracle.

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Speaker 1: It really is a miracle, a statistical anomaly totally.

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Speaker 2: So to understand how it all comes apart, I mean

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we have to start at the center of our.

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Speaker 1: Local neighborhood, the engine itself.

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Speaker 2: The engine of our solar system, the Sun.

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Speaker 1: Exactly, because the solar system doesn't die from an outside invasion.

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Speaker 2: No alien lasers, right.

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Speaker 1: No rogue black holes sweeping through at least not at first.

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It dies from internal organ failure.

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Speaker 2: Internal organ failure. Wow.

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Speaker 1: Yeah. And to understand why the Sun will eventually destroy

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the very planets it currently sustains, we have to look

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at how it sustains them in the first place.

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Speaker 2: Okay, let's unpack that.

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Speaker 1: You mentioned gravity trying to crush everything. Right now, the

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Sun is it's so incredibly massive that its own gravity

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is trying to collapse it into a tiny, hyperdense sphere.

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But it doesn't collapse, no, because it's fighting back. And

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this takes us back to Arthur Eddington's proposals. This was

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in nineteen twenty, right about nuclear fusion.

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Speaker 2: Yes, Eddington was a pioneer there.

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Speaker 1: The Sun is essentially just a gigantic, continuous nuclear explosion.

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I mean, it's taking hydrogen atoms smashing them together in

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the core at what fifteen million degrees.

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Speaker 2: About fifteen million degrees celsius, yes.

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Speaker 1: And fusing them into helium.

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Speaker 2: And that fifteen million degrees is the critical number because

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you know, atoms don't want.

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Speaker 1: To touch, right, electrostatic repulsion exactly.

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Speaker 2: That temperature is required to overcome the electrostatic repulsion of

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the hydrogen nuclei. They repel each other violently.

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Speaker 1: But the heat and pressure force them together anyway.

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Speaker 2: Right, And when they finally fuse, they release an incredible

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amount of energy in the form of photons light, light

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and heat. But those photons, they don't just straight out

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into space.

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Speaker 1: This is the part that blew my mind when I

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was reading this source material.

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Speaker 2: It's so counterintuitive. The core of the Sun is so

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unimaginably dense that a single photon of light created in

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that fusion reaction. It undergoes what physicists call a random walk.

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Speaker 1: A random walk because it keeps crashing into things constantly.

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Speaker 2: It bounces off atoms, gets absorbed, gets re emitted, ping

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ponging constantly, just zigzagging in this incredibly dense plasma trap

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for a very long time. Yes, it can take upwards

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of one hundred thousand years for that single photon to

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finally push its way from the core to the surface

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of the Sun.

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Speaker 1: Wait wait, so okay, think about this. The sunlight hitting

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your face right now, if you're standing outside listening to this,

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that light was actually generated in the core of the

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Sun one hundred thousand years ago. That's right, like during

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the place to see an epoch. While early humans were

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I don't know, discovering fire, the Sun was making the

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light that's hitting us today. That is absolutely statd.

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Speaker 2: It really messes with your sense of time. And all

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of those ancient photons pushing their way out, they create

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what we call radiation pressure, the outward push. Yes, this

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outward pressure perfectly balances the inward crush of gravity. Physicists

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call this hydrostatic equilibrium.

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Speaker 1: Hydrostatic equilibrium.

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Speaker 2: It's a beautiful, delicate standoff, just gravity pushing in, light

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pushing out. But here is the problem.

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Speaker 1: The gas tank is in bottomless exactly.

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Speaker 2: The ammunition for that outward push is finite. The Sun

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has a limited supply of hydrogen in its core, and

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it is already about four point six billion years into

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that supply, so it's middle aged very much. So it

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has roughly five billion years of hydrogen fuel remaining.

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Speaker 1: Which sounds like a really long time to us. But

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what fascinates me is the mechanism of what happens when

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the tank actually runs dry. It's not what you'd expect,

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not at all because intuitively, you know, if a fire

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runs out of fuel, gets smaller, it fades away into embers.

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But the Sun does the exact opposite. It becomes a

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red giant. It swells up massively to swallow the inner planets.

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So why does running out of fuel make the star

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get physically bigger?

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Speaker 2: That is the brilliant, sort of cruel counterintuition of stellar mechanics.

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When the core runs out of hydrogen.

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Speaker 1: Fusion stops, the engine cuts out, yes.

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Speaker 2: And suddenly that outward radiation pressure, all those photons fighting

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their way out that we just talked about, that pressure

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drops significantly.

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Speaker 1: And gravity doesn't take a break.

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Speaker 2: Never without that outward pressure, gravity instantly starts winning the

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tug of war. The core begins to collapse inward.

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Speaker 1: So the core does actually shrink at first.

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Speaker 2: The core shrinks, yes, it compresses, but remember your basic thermodynamics.

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When you compress a gas, what happens?

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Speaker 1: It heats up exactly.

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Speaker 2: As the dead helium ash core is crushed by gravity,

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its temperature skyrockets. Now surrounding this dead, shrinking core is

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a shell of hydrogen gas.

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Speaker 1: Gas that previously wasn't quite hot enough to fuse.

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Speaker 2: Right, right, It was just sitting there.

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Speaker 1: Yeah.

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Speaker 2: But as the collapsing core superheats from the compression, it

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acts like an incredibly powerful stove burner, oh wow, and

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it ignites that surrounding shell of hydrogen.

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Speaker 1: So the fusion moves from the center to like a

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ring around the center. They call it shell burning.

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Speaker 2: Precisely shell burning. And this new phase is far more

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vigorous and completely uncontrolled compared to the stable core fusion

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we have today.

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Speaker 1: BIG's a hotter, much hotter.

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Speaker 2: The energy output spikes massively. This new intense outward pressure

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from the shell overwhelms gravity in the outer layers of.

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Speaker 1: The star, so the outside gets pushed away, right.

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Speaker 2: It pushes the Sun's outer plasma envelope incredibly far out

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into space.

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Speaker 1: It's like it's like a pressure cooker where the internal

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thermostat completely breaks.

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Speaker 2: That's a great analogy, Like instead.

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Speaker 1: Of safely releasing steam, the pressure just builds exponentially in

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the outer layers until the whole apparatus balloons outwards. Yes,

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it inflates, and as it balloons, the surface actually cools

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down a bit, right, which is why it shifts on

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the light spectrum and turns red. A red giant exactly.

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Speaker 2: The surface is cooler, but the total heat output is monstrous.

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Speaker 1: And the physical physical size of it is terrifying. The

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outer atmosphere of the Sun will expand so far that

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it will physically engulf the orbit of mercury swallowed whole.

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Then we'll reach out and just completely swallow venus.

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Speaker 2: The sheer inevitability of it is what astrophysicists find so profound.

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There is no stopping that core collapse, and therefore no

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stopping the expansion. It's built into the physics.

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Speaker 1: Now, I've read conflicting models about Earth, specifically, like some

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say the Sun's physical plasma will actually reach Earth's orbit

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and swallow us too.

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Speaker 2: Yes, that's one model.

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Speaker 1: And then some say the Sun loses enough mass during

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this phase that Earth's orbit gets pushed back just enough

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to avoid physical contact.

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Speaker 2: Also a valid mathematical possibility, But.

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Speaker 1: Honestly, looking at the physics we're talking about, that debate

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feels entirely academic, Like it doesn't matter if we get

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physically touched by the plasma, does it.

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Speaker 2: It is entirely academic, because long before the physical boundary

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of the Sun reaches our orbital distance, its luminosity, its

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actual heat output will have increased by a factor.

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Speaker 1: Of thousands, thousands of times brighter.

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Speaker 2: Yes, you are no longer dealing with a warm, stable

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star ninety three million miles away. You are dealing with

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an angry wall of plasma taking up half the daytime sky.

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Speaker 1: The heat alone is just a total reset button. I mean,

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we are talking about the oceans boiling away into.

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Speaker 2: Space, completely evaporating, the.

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Speaker 1: Atmosphere being violently stripped off by these massive stellar winds.

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The very crust of the Earth, like the tectonic plates,

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the mountains, every single rock, yeah, every fossil, every single

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trace of human history, just melting into an ocean of

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glowing liquid rock. Like everything is sterilized.

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Speaker 2: The concept of survival in any localized sense is completely

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eradicated by the thermodynamics involved here.

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Speaker 1: No underground bunker is going to save you, not a chance.

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Speaker 2: You aren't just dealing with a severe climate shift. You

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are dealing with the physical state of the entire planet's

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surface transitioning from solid.

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Speaker 1: To liquid, which is horrifying. Yeah, but as terrifying as

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that red giant phase is for us on Earth, what

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is happening deep inside the core of the Sun at

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that exact moment is even more violent. Oh.

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Speaker 2: Absolutely, the surface is just a symptom, right.

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Speaker 1: The Sun doesn't just sit as a red giant forever.

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It's actually building toward a massive internal detonation, the helium flash.

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This is one of the most extreme events in stellar evolution,

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and again, gravity is the main culprire here.

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Speaker 2: Okay, take us into the core.

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Speaker 1: Remember that dead core of helium ash we talked about,

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the one that shranks. It's a stove burner, right, Well,

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it is continually being crushed by the immense weight of

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the expanding star above it. It gets denser and denser

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and hotter and hotter.

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Speaker 2: Because gravity won't quit exactly, but it doesn't behave like

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normal gas anymore.

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Speaker 1: Under that kind of pressure.

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Speaker 2: It enters this bizarre state governed by quantum mechanics, which

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we call electron degeneracy.

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Speaker 1: Okay, let's unpack electron degeneracy because this is where the

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physics gets ritibly weird.

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Speaker 2: Very weird.

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Speaker 1: Normally, if you heat up a gas, it expands, which

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cools it down. It's like a natural safety valve built

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into the.

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Speaker 2: Universe and negative feedback loop.

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Speaker 1: Yes, but in this core, the atoms are packed so

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tightly together that the poly exclusion principle kicks in.

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Speaker 2: Yes, exactly, the poly exclusion principle. It's a quantum rule

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stating that two identical fermions like electrons, for example, they

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cannot occupy the exact same quantum state simultaneously.

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Speaker 1: It can't sit in the same seat in the theater.

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Speaker 2: Good way to put it. Gravity has crushed this helium

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core so densely that all the available lower energy sets

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so to speak. For the electrons are completely filled, so

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they're jammed in. They are locked in place. The pressure

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holding the core up against gravity is no longer thermal

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pressure from heat. It is entirely quantum mechanical pressure.

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Speaker 1: And why is that dangerous for the star? Why does

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that cause an explosion?

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Speaker 2: Because it breaks that safety valve you mentioned ooh. In

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a normal gas, if the temperature goes up, the gas

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expands and cool down. But in degenerate matter, the pressure

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is completely disconnected from the temperature, so it can get

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hotter without expanding exactly, So as gravity continues to crush

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the core, the temperature rises towards a staggering one hundred million.

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Speaker 1: Degrees one hundred million, and at one.

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Speaker 2: Hundred million degrees, the helium finally ignites. It starts fusing

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into carbon.

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Speaker 1: But because it's degenerate matter, the core can't expand to

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cool itself down exactly.

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Speaker 2: The helium ignites, releasing massive amounts of heat. That heat

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makes the fusion reaction happen even faster, which releases even

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more heat, which makes the reaction even faster.

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Speaker 1: It's a runaway loop.

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Speaker 2: It is a runaway thermonuclear detonation.

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Speaker 1: Yeah.

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Speaker 2: Martin Schwartz's calculations back in nineteen fifty two really illuminated

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how violent this is.

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Speaker 1: Yeah, the numbers from Schwartz are insane.

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Speaker 2: In a matter of minutes, literally minutes, the entire core

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of the Sun undergoes this helium flash.

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Speaker 1: Min it's the whole star.

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Speaker 2: Yes, for that brief window, the core generates more power

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than the combined output of every single star in the

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entire Milky Way galaxy.

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Speaker 1: That is just unfathomable to me. A galactic level explosion

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contained entirely within the core of our Sun.

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Speaker 2: And it's buried so deep inside the star that it

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doesn't blow the Sun apart entirely, but it violently restructures

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the inside.

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Speaker 1: The Sun survives, it barely.

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Speaker 2: It survives, but it enters what astrophysicists call the horizontal

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branch phase.

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Speaker 1: And what strikes me here is that this is the

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moment the Sun fundamentally transitions, like it goes from being

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the stable anchor for five billion years into a wildly

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erratic dyeing machine. It's running on fumes, right. It starts

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burning through successive heavier fuels than these desperate violence spasms.

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Speaker 2: It's the cruel irony of stellar evolution. A dying star

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does not fade gently into the night because healum fusion

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is highly inefficient compared to hydrogen. This phase only lasts

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about one hundred million.

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Speaker 1: Years, which is a blink of an eye for a star, a.

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Speaker 2: Fraction of its life. The Sun is essentially consuming itself

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from the inside out in a series of shorter and

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increasingly violent reactions.

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Speaker 1: So any of the outer planets Jupiter, Saturn, Uranus, Neptune

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that managed to survive the initial red giant expansion they

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are now orbiting a star that is essentially having a

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sustained internal seizure.

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Speaker 2: Its mass is shifting, its energy output is erratic.

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Speaker 1: Which perfectly sets up the next mechanism of destruction we

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need to talk about. Because as the central anchor of

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our solar system starts acting erratically, the gravitational bonds holding

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the planets in their lanes, they begin to fray.

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Speaker 2: And this brings us to one of the most unnerving

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realizations in modern astrophysics. I think, Yeah, the seeds of

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our solar system's destruction are not just in the Sun dying.

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They are actually already planted in the gravitational relationships between

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the planets themselves.

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Speaker 1: Right now, Okay, this is where I want to push

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back on the timeline a bit. Yeah, because Jacques Lascar's

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two thousand and nine study at the Paris Observatory is

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widely cited here. Yes, a landmark study. He ran thousands

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of simulations on supercomputers basically trying to solve the n

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body problem for the Solar system, right.

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Speaker 2: Tracking the g gravitational influence of everything on everything else.

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Speaker 1: And he found a roughly one percent probability that Mercury's

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orbit completely destabilizes within the next five billion years, triggering

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a massive chaotic cascade.

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Speaker 2: Yes, the planetary billiards.

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Speaker 1: Well, wait, we know from chaos theory that the n

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body problem is inherently unpredictable over long time scales.

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Speaker 2: It's highly sensitive to initial conditions.

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Speaker 1: Right, A butterfly flapping its wings alters the gravitational math

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millions of years down the line. So how can LASCAR

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definitively claim a one percent chance of total chaos five

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billion years from now when we can't perfectly predict planetary

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positions even a few million years out.

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Speaker 2: It's a really good point.

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Speaker 1: Aren't these models fundamentally limited by that chaos?

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Speaker 2: That is exactly the right question to ask, and it

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actually highlights the genius of lascar's approach to this problem.

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You are absolutely correct that we cannot predict the exact

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position of mercury five.

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Speaker 1: Billion years from now. It's physically impossible.

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Speaker 2: Yes, the chaos makes specific positional prediction impossible. But Lescar

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wasn't looking for exact positions. He was modeling the statistical

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envelope of orbital evolution. The envelope, okay, by running thousands

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of slightly varied initial conditions. He wasn't predicting, you know,

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where mercury would be on a specific Tuesday, five billion

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years from now. He was calculating the boundary conditions of

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its orbit over time. And what he found was that

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the chaotic variations aren't just random, harmless noise.

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Speaker 1: It compound.

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Speaker 2: They compound in a very specific, dangerous way due to

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a mechanism called secular resonance.

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Speaker 1: Secular resonance, I love that term. This is the mechanism

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that basically turns a tiny little wobble into a full

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on planetary collision. How does that actually work? In physical terms?

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Speaker 2: Think of it like pushing a child on a swing. Okay,

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if you push at random times, sometimes when the swing

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is coming out you sometimes when it's moving away, the

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swing doesn't go very high. The energy cancels.

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Speaker 1: Out right, you just mess up their momentum.

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Speaker 2: But if you push at the eggs exact same point

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in the arc every single time, if you match the

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resonant frequency of the swing, you are pumping energy into the.

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Speaker 1: System and the child goes higher and higher.

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Speaker 2: Exactly.

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Speaker 1: Yeah.

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Speaker 2: In our solar system, Jupiter is the one doing the pushing.

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Speaker 1: Because Jupiter is just so massive it dominates the gravitational landscape. Right.

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Speaker 2: It's the bully of the Solar System. And while Jupiter

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and Mercury are incredibly far apart, they're orbital perihelions. The

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points where they are closest to the Sun gradually rotate

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around the Sun. Over millions of years.

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Speaker 1: The whole oval shape of the orbit slowly.

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Speaker 2: Spins, yes a psidal procession. Laskar showed that there is

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a chance these rotations will synchronize. Oh wow, Jupiter's massive

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gravity will start delivering a tiny, consistent gravitational tug to

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Mercury at the exact same relative point in its orbit

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millions of times over.

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Speaker 1: So Jupiter is perfectly timing its pushes on the swing exactly,

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and instead of making Mercury go higher, it stretches Mercury's orbit.

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It changes it from a relative circular path into an

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extreme oval. It increases its orbital eccentricity.

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Speaker 2: Jupiter is literally pumping angular momentum into Mercury's orbit. Year

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after year, eon after eon, Mercury's path gets more and more.

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Speaker 1: Elliptical, it gets stretched thinner and thinner.

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Speaker 2: And here is where the one percent probability becomes a

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terrifying reality. In a cosmic time frame. One percent isn't.

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Speaker 1: A long shot, it's an inevitability.

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Speaker 2: It's a guarantee waiting to happen. Time is the ultimate multiplier.

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If Mercury's orbit stretches far enough, its path crosses the orbit.

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Speaker 1: Of Venus, and once that happens, I mean the entire

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Inner Solar System turns into a chaotic game of planetary billiards.

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Speaker 2: All bets are off.

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Speaker 1: It's no longer just a slow, gentle gravitational tug its

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massive planetary bodies having near misses, and near misses in

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space are catastrophic because they warp orbits instantly.

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Speaker 2: They trade huge amounts of momentum.

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Speaker 1: The simulation show Mercury just being flung straight into the

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Sun or even ejected from the Solar System in times

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kicked out into the void. Yeah, and even worse, the

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gravitational shockwaves of Mercury running wild through the Inner System

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could destabilize Earth. The model show Venus in Earth could

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physically collide.

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Speaker 2: The profound takeaway here, I think is that no external

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force is required. You don't need a giant rogue asteroid

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to hit us. You don't need some sci fi alien

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death ray. The exact mathematical equations that keep our planets

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in this beautiful stable dance. Today, they contain the strict,

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unavoidable conditions of their own collapse.

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Speaker 1: It's baked into the math.

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Speaker 2: The Solar system is inherently self destructive over deep time.

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Speaker 1: I always pictured it like a spinning top on a table.

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Like if you watch it for a few seconds, it

404
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looks perfectly still, solid and completely stable, get straight up.

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But that stability is entirely dependent on its momentum. The

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second it loses just a fraction of a percent of

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that momentum, it begins.

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Speaker 2: To wabble, And once the wobble starts.

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Speaker 1: It violently crashes almost immediately. We are just living in

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the brief window where the top looks perfectly still.

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Speaker 2: That is a brilliant analogy. The wobble is coming. And

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remember this gravitational destabilization of the planets is happening at

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the exact same time the Sun is entering its most

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violent erratic phase.

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Speaker 1: Right. The timing is awful.

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Speaker 2: The asymptotic giant branch or AGB phase.

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Speaker 1: Right, So we have planets potentially playing demolition derby with

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each other, and meanwhile, the central star, the Sun is

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throwing the ultimate.

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Speaker 2: Tantrum a total meltdown.

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Speaker 1: Well. Dan Patchiski theorized this back in nineteen sixty six.

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During this AGB phase, the Sun doesn't just quietly burn

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one fuel. It has these alternating shells of hydrogen and

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helium that ignite and extinguish around the core like a

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sputtering engine. And it's not a smooth transition. These are

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massive thermal pulses.

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Speaker 2: The physical mechanics of a thermal pulse are staggering to

428
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think about. A shell of helium ignites, generating intense heat,

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which forces the outer layers of the Sun to expand massively.

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It balloons up again, but as it expands, it cools down.

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The heat reaction gets choked out and gravity pulls everything rapidly.

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Speaker 1: Back inwards, so it shrinks back down.

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Speaker 2: Then the hydrogen shell ignites again, building up more helium ash,

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until the whole cycle repeats.

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Speaker 1: Yeah, every one.

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Speaker 2: Hundred thousand years or so, the Sun swells up and contracts.

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Speaker 1: Violently expanding and shrinking.

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Speaker 2: And this lasts for roughly a million years.

439
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Speaker 1: Think about the gravitational whiplash that causes for everything orbiting it.

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We just talked about how a tiny consistent tug from

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Jupiter can completely ruin Mercury's orbit a tiny tug. Yes, Now,

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imagine the central anchor of the entire Solar system radically

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changing its physical size and its gravitational influence every one

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hundred thousand years. The entire system is effectively being shaken

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like a snow globe.

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Speaker 2: It is catastrophic, especially for the outer Solar system. Consider

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the Kuiper belt.

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Speaker 1: It comments out past Neptune right.

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Speaker 2: Billions of icy comets and dwarf planets out there. They're

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only loosely bound by the Sun's gravity to begin with,

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to just barely hang it on. So when the Sun

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pulses and its mass distribution shifts like that, those delicate

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gravitational tethers snap, they just break. The Kuiper bell is

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completely destabilized. Trillions of icy bodies are thrown out of

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their orbits. The Solar system becomes this chaotic shooting gallery

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with comets raining inward.

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Speaker 1: It's apocalyptic. But the Sun isn't just pulsing, It's actively disintegrating, yes,

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shedding its layers. And this leads us to one of

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the most paradoxical phenomena in astrophysics. I think in seventeen

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sixty four, Charles Messier cataloged this glowing shell of gas.

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Speaker 2: In space a beautiful discovery.

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Speaker 1: He didn't realize it at the time, but he was

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looking at a planetary nebula, which is the exact fate

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awaiting our own Sun.

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Speaker 2: During these violent agb thermal pulses, the outward pressure is

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so intense, and the outer layers of the Sun are

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pushed so far away from the core that gravity simply

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cannot hold onto them anymore.

469
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Speaker 1: It just lets go.

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Speaker 2: The Sun begins to shed its mass. It expels these

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massive waves of plasma out into space via stellar winds,

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and these winds are traveling at ten tens of kilometers

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per second. Over this entire phase, the Sun will lose

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up to fifty percent of its total mass.

475
00:23:06,640 --> 00:23:09,359
Speaker 1: Half of the Sun's mass is blown away into the void,

476
00:23:09,680 --> 00:23:11,640
like blowing the dandelion seeds into the wind.

477
00:23:11,759 --> 00:23:14,799
Speaker 2: Yes, and as those outer layers are completely stripped away,

478
00:23:14,880 --> 00:23:19,079
the unimaginably hot exposed core of the dying stars finally

479
00:23:19,160 --> 00:23:22,519
revealed the naked core. This core is emitting massive amounts

480
00:23:22,559 --> 00:23:27,200
of intense ultraviolet radiation, and that UV radiation hits the

481
00:23:27,240 --> 00:23:31,759
expanding shells of expelled gas, ionizing the atoms and causing

482
00:23:31,759 --> 00:23:33,119
them to glow brilliantly in.

483
00:23:33,079 --> 00:23:35,920
Speaker 1: All those vibrant reds, blues, and greens. Exactly. This is

484
00:23:35,920 --> 00:23:38,759
the paradox I'm talking about. Because we've all seen these

485
00:23:38,799 --> 00:23:42,680
images from the Hubble or James Webb telescopes. Oh, they're iconic,

486
00:23:42,799 --> 00:23:45,720
the Cat's eye nebula, the ring nebula. They are literally

487
00:23:45,720 --> 00:23:49,160
the most breathtaking, beautiful, colorful images of space we have.

488
00:23:49,200 --> 00:23:51,799
People have them on dorm room posters. They're gorgeous, but

489
00:23:51,839 --> 00:23:55,400
when you actually understand the physics, it is incredibly macabre.

490
00:23:56,039 --> 00:23:59,680
You are looking at a planetary graveyard, a crime scene. Yeah,

491
00:24:00,160 --> 00:24:03,160
the beautiful glowing gas is the evaporated atmosphere of a

492
00:24:03,240 --> 00:24:07,359
dying star, and buried inside that light is a chaotic

493
00:24:07,440 --> 00:24:11,319
maelstrom of destroyed planets. It's true like alien astronomers in

494
00:24:11,359 --> 00:24:13,200
a distanced oar system might look at our Sun in

495
00:24:13,240 --> 00:24:17,079
five billion years see a gorgeous, glowing ring of color

496
00:24:17,160 --> 00:24:20,519
through their telescopes and have no idea. They are looking

497
00:24:20,519 --> 00:24:23,240
at the absolute erasure of Earth and everything we ever were.

498
00:24:23,599 --> 00:24:26,680
Speaker 2: It perfectly encapsulates the indifference of the universe, doesn't it.

499
00:24:26,839 --> 00:24:29,880
Cosmic destruction is often esthetically.

500
00:24:29,440 --> 00:24:32,200
Speaker 1: Magnificent, beautiful, but deadly, But the.

501
00:24:32,079 --> 00:24:35,759
Speaker 2: Physical consequences for our Solar System during this mass shedding

502
00:24:35,799 --> 00:24:39,880
phase are permanent, because as the Sun loses half its mass,

503
00:24:40,359 --> 00:24:44,000
its gravitational grip on the remaining planets completely weakened.

504
00:24:44,079 --> 00:24:47,599
Speaker 1: This is the great dispersal, like an aging king losing

505
00:24:47,640 --> 00:24:50,720
his empire. If you weaken the gravity holding the planets

506
00:24:50,720 --> 00:24:54,039
in their orbits have to expand they just drift outward.

507
00:24:54,279 --> 00:24:57,400
Jupiter might drift from its current five astronomical units out

508
00:24:57,400 --> 00:25:00,559
to ten. Neptune might be pushed so so far out

509
00:25:00,559 --> 00:25:02,880
that the Sun's weakened gravity can't hold it at all,

510
00:25:02,960 --> 00:25:05,279
and it just slips its leash entirely. It becomes a

511
00:25:05,359 --> 00:25:09,640
rogue planet, just drifting alone in interstellar space. The Solar

512
00:25:09,640 --> 00:25:13,160
System is a structured, cohesive unit is just completely disassembled.

513
00:25:13,359 --> 00:25:16,160
Speaker 2: The ties that mine the system together are entirely suvered.

514
00:25:16,200 --> 00:25:19,039
And what is left behind, You know, once that beautiful

515
00:25:19,119 --> 00:25:22,680
glowing nebula of gas finally expands and dissipates into the

516
00:25:22,720 --> 00:25:25,799
interstellar medium, what sits at the center of the graveyard

517
00:25:25,960 --> 00:25:26,920
the ultimate corpse.

518
00:25:27,680 --> 00:25:31,119
Speaker 1: A white dwarf astronomer Walter Adams confirmed their existence in

519
00:25:31,200 --> 00:25:35,359
nineteen fourteen. By looking at the companion, start serious, and

520
00:25:35,400 --> 00:25:38,680
the physical reality of a white dwarf just completely breaks

521
00:25:38,720 --> 00:25:39,079
the brain.

522
00:25:39,279 --> 00:25:40,559
Speaker 2: It's hard to visualize.

523
00:25:40,680 --> 00:25:43,160
Speaker 1: After the Sun sheds its utter layers, all that remains

524
00:25:43,200 --> 00:25:46,119
is that dead carbon oxygen core we talked about earlier.

525
00:25:46,440 --> 00:25:49,000
It contains roughly half the mass of our original Sun,

526
00:25:49,640 --> 00:25:52,599
but it has been crushed by gravity into a sphere

527
00:25:52,680 --> 00:25:53,599
the size of the Earth.

528
00:25:53,799 --> 00:25:57,160
Speaker 2: Think about that density for a second. You're taking fifty

529
00:25:57,160 --> 00:26:00,000
percent of the Sun's mass, hundreds of thousands of times

530
00:26:00,279 --> 00:26:02,440
the mass of the Earth and packing it into a

531
00:26:02,519 --> 00:26:04,160
volume no larger than our planet.

532
00:26:04,200 --> 00:26:04,799
Speaker 1: It's insane.

533
00:26:05,079 --> 00:26:08,440
Speaker 2: A single teaspoon of white dwarf material would weigh several

534
00:26:08,440 --> 00:26:11,160
tons on Earth a teaspoon. And again, it is held

535
00:26:11,240 --> 00:26:13,880
up entirely by electron degeneracy pressure.

536
00:26:13,960 --> 00:26:15,559
Speaker 1: The quantum seeds are full, exactly.

537
00:26:15,720 --> 00:26:18,519
Speaker 2: Yeah, the quander resistance of electrons is the literal only

538
00:26:18,599 --> 00:26:21,279
thing preventing it from collapsing entirely into a black hole.

539
00:26:21,400 --> 00:26:25,000
Speaker 1: And it is searingly hot, like one hundred thousand degrees

540
00:26:25,039 --> 00:26:27,880
celsius on the surface. Yeah. But here's the key, the

541
00:26:27,920 --> 00:26:31,039
really sad part. There is no fusion.

542
00:26:31,279 --> 00:26:32,160
Speaker 2: The engine is dead.

543
00:26:32,240 --> 00:26:34,200
Speaker 1: It is no longer creating any new energy.

544
00:26:34,400 --> 00:26:38,559
Speaker 2: It is simply a massively hot rock radiating its residual

545
00:26:38,599 --> 00:26:42,000
thermal energy into the absolute zero vacuum of space.

546
00:26:42,359 --> 00:26:46,079
Speaker 1: It's exactly like pulling a glowing red hot coal out

547
00:26:46,079 --> 00:26:48,640
of a campfire. Yeah, it's incredibly hot to the touch,

548
00:26:48,880 --> 00:26:52,039
and it glows brightly, but there is no chemical reaction

549
00:26:52,200 --> 00:26:54,720
happening inside it anymore. Right, it's just cooling. It is

550
00:26:54,799 --> 00:26:57,480
just slowly, inevitably giving up its heat to the cold

551
00:26:57,480 --> 00:27:01,039
air of the forest. Except for this white dwarf, the

552
00:27:01,079 --> 00:27:04,319
forest is the entire universe, and the cooling process takes

553
00:27:04,319 --> 00:27:07,000
a timescale that makes the age of the universe look

554
00:27:07,039 --> 00:27:07,880
like a rounding error.

555
00:27:08,079 --> 00:27:10,640
Speaker 2: This is where we have to fundamentally adjust how we

556
00:27:10,720 --> 00:27:15,160
perceive time. A white dwarf cools solely through thermal radiation.

557
00:27:15,160 --> 00:27:16,960
Speaker 1: Just bleeding heat into the dark. Right.

558
00:27:17,240 --> 00:27:19,079
Speaker 2: It has a massive amount of stored heat and a

559
00:27:19,119 --> 00:27:21,839
relatively very small surface area to radiate it from, so

560
00:27:21,880 --> 00:27:26,400
it cools imperceptibly slowly. It transitions from white to yellow

561
00:27:26,440 --> 00:27:28,680
to red over trillions of years.

562
00:27:28,440 --> 00:27:31,640
Speaker 1: And eventually it goes completely dark. It becomes a black dwarf, Yes,

563
00:27:31,720 --> 00:27:34,599
a frozen lightless cinder at the exact temperature of the

564
00:27:34,640 --> 00:27:37,839
cosmic background radiation. But here is the detail from our

565
00:27:37,880 --> 00:27:40,079
sources that literally made me stop reading.

566
00:27:40,359 --> 00:27:41,480
Speaker 2: Oh, I know which one you mean.

567
00:27:41,920 --> 00:27:43,720
Speaker 1: We talk about black drfs as the final state of

568
00:27:43,759 --> 00:27:46,559
a star, but the time required for white dwarf to

569
00:27:46,559 --> 00:27:49,240
cool down into a black dwarf is estimated to be

570
00:27:49,319 --> 00:27:50,839
roughly a quadrillion years.

571
00:27:51,000 --> 00:27:54,759
Speaker 2: A quadrillion ten to the fifteenth power.

572
00:27:54,880 --> 00:27:58,559
Speaker 1: That's a one followed by fifteen zeros. The universe itself

573
00:27:58,599 --> 00:28:02,079
is only thirteen point eight billion years old. The universe

574
00:28:02,119 --> 00:28:05,039
is practically a newborn baby compared to the time it

575
00:28:05,079 --> 00:28:08,160
takes to make a black dwarf. It's barely started. So currently,

576
00:28:08,279 --> 00:28:11,839
right now, in the entire infinite expanse of the cosmos,

577
00:28:12,079 --> 00:28:15,640
not a single black dwarf exists. Reality has been around

578
00:28:15,640 --> 00:28:16,920
long enough to make even one.

579
00:28:17,160 --> 00:28:20,039
Speaker 2: It is a profound realization. Everything we observe in the

580
00:28:20,079 --> 00:28:23,319
night sky right now, every galaxy, every quasar, every supernova,

581
00:28:23,480 --> 00:28:27,480
it all represents the chaotic, fiery infancy of the universe.

582
00:28:27,559 --> 00:28:31,079
Just the opening credits, the vast overwhelming majority of the

583
00:28:31,160 --> 00:28:34,079
universe's lifespan will actually be spent in the dark populated

584
00:28:34,119 --> 00:28:36,160
exclusively by these invisible black dwarfs.

585
00:28:36,200 --> 00:28:38,400
Speaker 1: Now, I have to ask the skeptics question here go

586
00:28:38,519 --> 00:28:40,559
for it. If the universe isn't even old enough for

587
00:28:40,640 --> 00:28:44,240
a single black dwarf to exist, how can physicists speak

588
00:28:44,279 --> 00:28:48,240
with such absolute certainty about a timeline a kadrillion years away?

589
00:28:48,359 --> 00:28:48,920
Speaker 2: That's fair?

590
00:28:49,039 --> 00:28:52,079
Speaker 1: Are we not assuming that our current understanding of thermodynamics

591
00:28:52,119 --> 00:28:56,200
will just hold up indefinitely? Like what about quantum fluctuations

592
00:28:56,279 --> 00:28:59,799
or proton decay generating residual heat? How are we so?

593
00:29:00,759 --> 00:29:04,519
Speaker 2: You are referencing the very deepest edges of theoretical physics. There,

594
00:29:05,200 --> 00:29:08,119
it is true that on a timescale of a quadrillion years,

595
00:29:08,359 --> 00:29:14,119
extremely rare quantum events become statistically probable. However, the macro

596
00:29:14,240 --> 00:29:17,279
cooling of a macroscopic object like a white dwarf is

597
00:29:17,319 --> 00:29:19,519
governed by the rigid, unbreakable laws.

598
00:29:19,279 --> 00:29:20,680
Speaker 1: Of thermodynamics entropy.

599
00:29:20,920 --> 00:29:26,079
Speaker 2: Yes, while quantum fluctuations might provide incredibly tiny, localized spikes

600
00:29:26,119 --> 00:29:30,880
of energy, they cannot overcome the macroscale thermodynamic imperative of entropy.

601
00:29:31,279 --> 00:29:33,240
Heat flows from warmer to colder period.

602
00:29:33,359 --> 00:29:34,400
Speaker 1: The house always wins.

603
00:29:34,440 --> 00:29:37,200
Speaker 2: The house always wins. The white dwarf must cool the

604
00:29:37,200 --> 00:29:40,519
physics of radiation in a vacuum is ironclad, irrespective of

605
00:29:40,519 --> 00:29:43,880
whether the universe is fourteen billion or a quadrillion years old.

606
00:29:43,880 --> 00:29:47,079
Speaker 1: It's unavoidable. And while that central ember is spending a

607
00:29:47,160 --> 00:29:51,559
quadrillion years just cooling off, the extreme outer edges of

608
00:29:51,599 --> 00:29:55,720
our Solar system are meeting their own silent, invisible end.

609
00:29:55,920 --> 00:29:59,039
Yes the final dispersal. In nineteen fifty yan or It

610
00:29:59,200 --> 00:30:01,839
mapped out the map mathematics of the Oort Cloud, this

611
00:30:02,039 --> 00:30:06,240
massive spherical shell of trillions of icy comets enveloping the

612
00:30:06,279 --> 00:30:07,279
whole Solar System.

613
00:30:07,359 --> 00:30:10,960
Speaker 2: These objects are incredibly distant. We're talking distances up to

614
00:30:11,000 --> 00:30:13,599
one hundred thousand times the distance between the.

615
00:30:13,559 --> 00:30:15,359
Speaker 1: Earth and the Sun, way way out there.

616
00:30:15,440 --> 00:30:18,880
Speaker 2: At that range, the Sun's gravity is incredibly weak. It

617
00:30:18,960 --> 00:30:21,799
is barely a whisper holding these comets in orbit.

618
00:30:22,000 --> 00:30:24,200
Speaker 1: And since the Sun lost half its mass during the

619
00:30:24,200 --> 00:30:29,079
planetary nebula phase, that whisper fades completely. Gravitational tether is

620
00:30:29,160 --> 00:30:32,960
just broken. It snaps those trillions of comets, these priskine

621
00:30:32,960 --> 00:30:35,400
frozen time capsules from the very formation of the Solar

622
00:30:35,400 --> 00:30:38,559
System four point six billion years ago. They simply let go.

623
00:30:38,720 --> 00:30:41,440
They untethered, They aren't thrown violently. Like the inner planets,

624
00:30:41,440 --> 00:30:44,000
they just drift away to the interstellar foid in total silence,

625
00:30:44,519 --> 00:30:47,440
over billions of years. Passing stars and galactic tides will

626
00:30:47,480 --> 00:30:49,920
just sweep them up. The outer boundary of our home

627
00:30:50,000 --> 00:30:50,759
is just erased.

628
00:30:51,039 --> 00:30:55,039
Speaker 2: It is a quiet dissolution, a slow fade out. But

629
00:30:55,160 --> 00:30:58,160
while our immediate neighborhood is freezing and drifting apart the

630
00:30:58,200 --> 00:31:02,119
macro environment, the galaxy itself is preparing a much much

631
00:31:02,160 --> 00:31:05,160
more violent fate for whatever remains of our dead system.

632
00:31:05,440 --> 00:31:07,119
Speaker 1: This is the part of the timeline I like to

633
00:31:07,119 --> 00:31:09,720
call double Jeopardy, good name for it, because we've been

634
00:31:09,759 --> 00:31:13,359
completely focused on our son's internal mechanisms. But if we

635
00:31:13,480 --> 00:31:16,119
zoom out to the galactic scale, we are on a

636
00:31:16,119 --> 00:31:20,960
collision course, a literal physical collision course, with the Andromeda galaxy.

637
00:31:21,160 --> 00:31:24,640
Speaker 2: In twenty twelve, incredibly precise measurements from the Hubble Space

638
00:31:24,720 --> 00:31:28,599
telescope confirmed the exact vector and velocity of Andromeda.

639
00:31:28,640 --> 00:31:29,640
Speaker 1: It's head and right for us.

640
00:31:29,759 --> 00:31:33,000
Speaker 2: It is a massive spiral galaxy, larger than our Milky Way,

641
00:31:33,319 --> 00:31:35,599
and it is hurtling toward us at roughly one hundred

642
00:31:35,640 --> 00:31:36,880
and ten kilometers per.

643
00:31:36,759 --> 00:31:39,480
Speaker 1: Second, and the timing is practically a cosmic joke. The

644
00:31:39,480 --> 00:31:42,119
collision is slated to begin in approximately four point five

645
00:31:42,160 --> 00:31:43,759
to five billion years.

646
00:31:43,680 --> 00:31:45,200
Speaker 2: Which perfectly coincides.

647
00:31:45,559 --> 00:31:48,759
Speaker 1: It perfectly coincides with our son running out of hydrogen

648
00:31:48,799 --> 00:31:52,160
and expanding into a red giant. So while our sun

649
00:31:52,279 --> 00:31:55,599
is violently bowling the oceans and swallowing venus, the entire

650
00:31:55,680 --> 00:31:58,200
night sky above that dying sun is going to be

651
00:31:58,279 --> 00:32:01,960
filled with the approaching spiral arms arms of an alien galaxy.

652
00:32:02,039 --> 00:32:05,720
Speaker 2: It is two completely separate catastrophes unfolding at the exact

653
00:32:05,720 --> 00:32:06,319
same time.

654
00:32:06,559 --> 00:32:10,519
Speaker 1: The visual of that sky would be terrifyingly majestic, which

655
00:32:10,599 --> 00:32:13,440
is this massive, glowing spiral taking up the whole field

656
00:32:13,480 --> 00:32:15,359
of view. But let's look at the physics of a

657
00:32:15,359 --> 00:32:18,000
galactic merger, because it's highly counterintuitive, right it.

658
00:32:17,960 --> 00:32:22,000
Speaker 2: Is when two galaxies collide, the stars themselves almost never

659
00:32:22,079 --> 00:32:23,079
actually hit each other.

660
00:32:23,200 --> 00:32:25,680
Speaker 1: Wait really, with billions of stars, yes.

661
00:32:26,000 --> 00:32:29,559
Speaker 2: The space between stars is so unfathomably vast that the

662
00:32:29,599 --> 00:32:32,400
two galaxies essentially pass through one another like ghosts.

663
00:32:32,559 --> 00:32:36,039
Speaker 1: Right, It's not a demolition derby of stars physically smashing

664
00:32:36,039 --> 00:32:38,240
together like cars. It's a gravitational war.

665
00:32:38,480 --> 00:32:42,440
Speaker 2: Exactly, the sheer mass of these two galaxies interacting creates

666
00:32:42,599 --> 00:32:45,759
monstrous tidal forces. It is a process that takes one

667
00:32:45,759 --> 00:32:47,720
to two billion years to fully.

668
00:32:47,400 --> 00:32:49,519
Speaker 1: Settle a billion year car crash.

669
00:32:49,880 --> 00:32:52,799
Speaker 2: As the galaxies pass through each other, swing back around,

670
00:32:52,880 --> 00:32:56,599
and merge into a single elliptical galaxy, what astronomers playfully

671
00:32:56,640 --> 00:33:01,799
call milk comeda. Milk comeda, the gravitational feels are wildly chaotic.

672
00:33:01,920 --> 00:33:04,559
Stars are violently ripped from their ancestral orbits.

673
00:33:04,559 --> 00:33:07,039
Speaker 1: And where does our dying solar system, or what's left

674
00:33:07,079 --> 00:33:09,359
of it, end up in this new Milkomata galaxy.

675
00:33:09,440 --> 00:33:12,200
Speaker 2: The simulations show it is largely a roll of the dice.

676
00:33:12,680 --> 00:33:15,279
We could be caught in a massive tidal tale and

677
00:33:15,440 --> 00:33:18,480
flung out into the extreme outer edges of the new.

678
00:33:18,359 --> 00:33:20,400
Speaker 1: Galaxy, cast out into the dark.

679
00:33:20,319 --> 00:33:22,440
Speaker 2: Cast into the lonely intergalactic halo.

680
00:33:22,599 --> 00:33:22,920
Speaker 1: Yes.

681
00:33:23,359 --> 00:33:27,599
Speaker 2: Or conversely, we could lose orbital angular momentum and be

682
00:33:27,759 --> 00:33:31,000
dragged deep into the chaotic, dense new core of the

683
00:33:31,079 --> 00:33:32,000
merged galaxy.

684
00:33:32,119 --> 00:33:34,119
Speaker 1: And if we get dragged into the core, we meet

685
00:33:34,160 --> 00:33:38,359
the final boss of gravitational destruction, Sagittarius.

686
00:33:37,680 --> 00:33:39,200
Speaker 2: A the Monster in the middle.

687
00:33:39,480 --> 00:33:43,319
Speaker 1: In nineteen seventy four, Bruce Bailick and Robert Brown detected

688
00:33:43,319 --> 00:33:46,119
a powerful radio source at the center of the Milky Way,

689
00:33:46,359 --> 00:33:49,039
which we now know is a supermassive black hole. It

690
00:33:49,039 --> 00:33:51,359
contains the mass of roughly four million.

691
00:33:51,079 --> 00:33:55,680
Speaker 2: Suns, and Andromeda has an even larger supermassive black hole

692
00:33:55,720 --> 00:33:59,640
at its center. During the merger, these two supermassive black

693
00:33:59,680 --> 00:34:03,400
holes will eventually spiral in toward each other and merge.

694
00:34:03,039 --> 00:34:06,359
Speaker 1: Sending massive gravitational waves rippling through space.

695
00:34:06,119 --> 00:34:11,119
Speaker 2: Time exactly, the new combined supermassive black hole will completely

696
00:34:11,199 --> 00:34:13,079
dominate the center of Milcomato.

697
00:34:13,719 --> 00:34:17,119
Speaker 1: Currently, we orbit the galactic center at a very safe

698
00:34:17,119 --> 00:34:20,320
distance of about twenty six thousand light years, but orbits

699
00:34:20,360 --> 00:34:23,360
are not eternal. This is another mechanism we need to unpack.

700
00:34:24,239 --> 00:34:27,719
Orbit'll decay, yes nothing orbits forever over tens of billions

701
00:34:27,719 --> 00:34:31,639
of years, moving through the interstellar medium, interacting gravitationally with

702
00:34:31,679 --> 00:34:35,559
passing stars and emitting tiny amounts of energies gravitational ways,

703
00:34:35,920 --> 00:34:38,960
our orbit around the galactic center will inevitably shrink. We

704
00:34:39,000 --> 00:34:39,960
will spiral inward.

705
00:34:40,159 --> 00:34:43,920
Speaker 2: It is a slow, agonizing drag, and as are dead

706
00:34:44,079 --> 00:34:46,559
frozen black dwarf of a sun is pulled closer and

707
00:34:46,599 --> 00:34:50,199
closer to the central supermassive black hole, the environment turns

708
00:34:50,239 --> 00:34:51,119
fiercely hostile.

709
00:34:51,199 --> 00:34:51,960
Speaker 1: It gets crowded.

710
00:34:52,159 --> 00:34:54,960
Speaker 2: The stellar density near the core is immense. Stars are

711
00:34:54,960 --> 00:34:57,679
whipping around the black hole at velocities exceeding ten thousand

712
00:34:57,719 --> 00:34:58,800
kilometers per second.

713
00:34:59,079 --> 00:35:01,840
Speaker 1: And if if our dead sun gets too close to

714
00:35:01,880 --> 00:35:04,800
the black hole, it doesn't just quietly fall in, does it.

715
00:35:04,800 --> 00:35:08,880
It gets shredded by the tidal forces. The mechanism here

716
00:35:08,960 --> 00:35:10,239
is called spaghettification.

717
00:35:10,480 --> 00:35:11,599
Speaker 2: I know it sounds like a good joke.

718
00:35:11,920 --> 00:35:15,719
Speaker 1: It sounds hilarious that the physics are completely brutal.

719
00:35:15,880 --> 00:35:19,119
Speaker 2: The gravitational ingradient of a supermassive black hole is so

720
00:35:19,280 --> 00:35:23,079
steep that the force of gravity changes drastically over very

721
00:35:23,119 --> 00:35:23,960
short distances.

722
00:35:24,360 --> 00:35:26,039
Speaker 1: What does that mean for an object falling in?

723
00:35:26,719 --> 00:35:29,840
Speaker 2: If our dead sun approaches the black hole, the gravitational

724
00:35:29,880 --> 00:35:32,000
pole on the side of the Sun facing the black

725
00:35:32,039 --> 00:35:35,280
hole is vastly measurably stronger than the pole on the

726
00:35:35,280 --> 00:35:35,880
far side.

727
00:35:35,920 --> 00:35:37,880
Speaker 1: So the front of the star is being yanked way

728
00:35:37,920 --> 00:35:40,320
harder than the back of the star. It physically stretches

729
00:35:40,360 --> 00:35:41,599
the object, yes, and.

730
00:35:41,559 --> 00:35:44,920
Speaker 2: It compresses it from the sides simultaneously. The tidal forces

731
00:35:45,000 --> 00:35:49,440
simply overwhelm the sheer structural integrity of the carbon oxygen dwarf.

732
00:35:49,440 --> 00:35:50,559
Speaker 1: He just rips it apart.

733
00:35:50,719 --> 00:35:54,519
Speaker 2: The dead star and any frozen planetary remnants still clinging

734
00:35:54,519 --> 00:35:57,119
to it are literally ripped apart into a stream of

735
00:35:57,159 --> 00:35:58,440
superheated plasma.

736
00:35:58,679 --> 00:36:02,599
Speaker 1: They are stretched into an infinitesimally thin river of atoms,

737
00:36:02,880 --> 00:36:06,360
spiraling down the accretion disk and eventually crossing the event horizon.

738
00:36:06,760 --> 00:36:11,039
Gone forever to go back to our central thesis, Gravity

739
00:36:11,360 --> 00:36:14,960
always wins. It crushes the Sun, It destabilizes the planets,

740
00:36:15,000 --> 00:36:18,440
It merges the galaxies, and eventually the supermassive black hole

741
00:36:18,440 --> 00:36:21,320
at the center acts as the ultimate cosmic vacuum cleaner.

742
00:36:21,360 --> 00:36:25,480
Speaker 2: Gravity is relentless. It's the ultimate eraser. But what if

743
00:36:25,519 --> 00:36:26,360
we consider an.

744
00:36:26,360 --> 00:36:28,239
Speaker 1: Escapee ooh, an escapey okay.

745
00:36:28,320 --> 00:36:31,159
Speaker 2: Let's imagine a scenario where the chaotic merger of the

746
00:36:31,199 --> 00:36:34,760
galaxies flung our dead Sun entirely out of the galaxy

747
00:36:35,159 --> 00:36:37,400
into the deep intergalactic void.

748
00:36:37,199 --> 00:36:39,159
Speaker 1: So we missed the black hole, entirely.

749
00:36:39,000 --> 00:36:41,559
Speaker 2: Safe from the black hole, safe from collisions.

750
00:36:41,199 --> 00:36:45,159
Speaker 1: Safe isolated, and just floating in the dark forever. Except well,

751
00:36:45,360 --> 00:36:47,719
forever is where physics draws a hard line.

752
00:36:47,760 --> 00:36:49,239
Speaker 2: It certainly does, because even.

753
00:36:49,079 --> 00:36:52,280
Speaker 1: If a single atom of Earth manages to survive the

754
00:36:52,320 --> 00:36:56,079
Sun's death, survive the planetary billiard, survive the galactic collision,

755
00:36:56,400 --> 00:37:00,119
and completely escape the black hole it still face. This

756
00:37:00,159 --> 00:37:04,280
is the ultimate inescapable law of reality, the end of everything.

757
00:37:04,599 --> 00:37:07,920
Speaker 2: We are talking about the concept of universal heat death,

758
00:37:08,400 --> 00:37:11,320
and this brings us to the physicist William Thompson Lord

759
00:37:11,400 --> 00:37:14,679
Kelvin back in eighteen fifty one, the thermodynamics guy. He

760
00:37:14,760 --> 00:37:18,280
formulated this based on the second law of thermodynamics, which

761
00:37:18,280 --> 00:37:20,679
states that in any closed system, and the universe is

762
00:37:20,719 --> 00:37:24,360
the ultimate closed system, entropy always increases.

763
00:37:24,159 --> 00:37:27,679
Speaker 1: Entropy basically being the measure of disorder, or more accurately,

764
00:37:28,079 --> 00:37:30,000
the dispersal of energy exactly.

765
00:37:30,159 --> 00:37:33,840
Speaker 2: Energy inevitably moves from concentrated usable forms like the hot

766
00:37:33,880 --> 00:37:38,280
core of a star, into diffuse, unusable forms like ambient

767
00:37:38,320 --> 00:37:40,159
heat radiating into empty space.

768
00:37:40,440 --> 00:37:41,760
Speaker 1: Hot objects cool down.

769
00:37:41,880 --> 00:37:45,559
Speaker 2: Highly structured things like galaxies or planets or biological life

770
00:37:45,639 --> 00:37:49,199
eventually decay into disorder, and this process is a one

771
00:37:49,199 --> 00:37:51,719
way street. You cannot unburn a log of wood.

772
00:37:51,840 --> 00:37:54,239
Speaker 1: Once the heat is gone, it's gone. So let's map

773
00:37:54,280 --> 00:37:57,199
out this final timeline. Because the numbers here completely break

774
00:37:57,320 --> 00:37:59,159
the human ability to comprehend scale.

775
00:37:59,320 --> 00:38:00,559
Speaker 2: They are absurd numbers.

776
00:38:00,679 --> 00:38:03,119
Speaker 1: We are long past the era of black dwarfs. We

777
00:38:03,159 --> 00:38:05,559
are looking at ten to the fourteenth power years into

778
00:38:05,559 --> 00:38:06,039
the future.

779
00:38:06,159 --> 00:38:09,440
Speaker 2: At that point, the degenerate era begins. Star formation has

780
00:38:09,440 --> 00:38:10,360
completely ceased.

781
00:38:10,800 --> 00:38:12,239
Speaker 1: No new stars are being born.

782
00:38:12,480 --> 00:38:16,000
Speaker 2: The universe has expanded so much, and the remaining hydrogen

783
00:38:16,039 --> 00:38:19,400
gas is spread so incredibly thin that gravity can no

784
00:38:19,480 --> 00:38:23,280
longer pull it together to ignite new stars. The last

785
00:38:23,599 --> 00:38:27,639
slow burning red dwarf stars flicker out, the lights go out.

786
00:38:27,719 --> 00:38:31,760
The universe goes completely dark. It is populated exclusively by

787
00:38:31,840 --> 00:38:36,039
stellar corpses, white dwarfs, neutron stars, and black holes.

788
00:38:36,440 --> 00:38:39,239
Speaker 1: Just a cemetery of dead stars drifting further and further

789
00:38:39,280 --> 00:38:42,559
apart as the universe continues to expand. But even those

790
00:38:42,559 --> 00:38:45,719
corpses aren't internal. No, they aren't. Let's fast forward to

791
00:38:45,719 --> 00:38:48,920
ten to the fortieth power years. This introduces a theoretical

792
00:38:48,960 --> 00:38:52,760
physics concept that sounds like pure science fiction, proton decay.

793
00:38:52,960 --> 00:38:56,000
Speaker 2: This is a cornerstone of many grand, unified theories in physics.

794
00:38:56,400 --> 00:38:59,840
These theories suggest that protons the fundamental building blocks of

795
00:39:00,000 --> 00:39:02,599
atomic nuclei, the things that make up everything from a

796
00:39:02,679 --> 00:39:05,039
rock to a human being to a dead star. They

797
00:39:05,079 --> 00:39:08,639
are not perfectly stable. They don't last forever over unimaginably

798
00:39:08,679 --> 00:39:09,559
long time scales.

799
00:39:09,599 --> 00:39:13,760
Speaker 1: They decay so buryonic matter, the physical stuff of the universe,

800
00:39:14,159 --> 00:39:17,760
literally dissolves. Every single atom that makes up the frozen

801
00:39:17,760 --> 00:39:21,239
black bwarf of our sun. Any surviving rogue planets, any

802
00:39:21,239 --> 00:39:23,440
distant asteroids, they simply disintegrate.

803
00:39:23,639 --> 00:39:24,480
Speaker 2: They fade away.

804
00:39:24,679 --> 00:39:28,840
Speaker 1: They evaporate, particle by particle into subatomic leptons and photons,

805
00:39:29,000 --> 00:39:31,320
which then just disperse into the expanding void.

806
00:39:31,519 --> 00:39:35,559
Speaker 2: All solid matter ceases to exist. The only structured objects

807
00:39:35,639 --> 00:39:38,320
left in the entire universe at this point are black holes,

808
00:39:39,039 --> 00:39:42,840
the absolute titans of gravity, holding immense amounts of mass

809
00:39:42,920 --> 00:39:44,559
locked inside their event horizons.

810
00:39:44,960 --> 00:39:47,800
Speaker 1: But even the black holes can't defeat thermodynamics, can they.

811
00:39:48,320 --> 00:39:51,320
In nineteen seventy four, Stephen Hawking blew the world of

812
00:39:51,320 --> 00:39:54,159
physics wide open by proving that black holes are not

813
00:39:54,360 --> 00:39:55,880
completely black. They leak.

814
00:39:56,119 --> 00:39:59,639
Speaker 2: Hawking radiation is a brilliant synthesis of quantum mechanics and

815
00:39:59,679 --> 00:40:04,079
graph In the vacuum of space, quantum fields are constantly fluctuating,

816
00:40:04,119 --> 00:40:07,840
bubbling with energy pairs of virtual particles, a particle and

817
00:40:07,880 --> 00:40:12,400
an antiparticle are constantly popping into existence, colliding and annihilating

818
00:40:12,400 --> 00:40:14,800
each other in a fraction of a second. But Hawking

819
00:40:14,880 --> 00:40:17,519
realized that if this particle pair forms exactly on the

820
00:40:17,519 --> 00:40:20,800
boundary of a black hole's event horizon, the intense gravity

821
00:40:20,840 --> 00:40:24,119
can pull one particle in while the other escapes into space.

822
00:40:24,280 --> 00:40:28,639
Speaker 1: Yet the escaping particle effectively steals a minuscule, almost unmeasurable

823
00:40:28,639 --> 00:40:30,199
fraction of the black hole's mass.

824
00:40:30,280 --> 00:40:34,039
Speaker 2: Yes, the black hole is slowly evaporating. It is an

825
00:40:34,199 --> 00:40:39,320
agonizingly slow process. The largest supermassive black holes won't fully

826
00:40:39,360 --> 00:40:43,400
evaporate until approximately ten to the hundredth power years.

827
00:40:43,119 --> 00:40:45,880
Speaker 1: From now ten to the hundredth power a google of years.

828
00:40:46,400 --> 00:40:48,199
It's a number so large that if you wrote a

829
00:40:48,280 --> 00:40:50,760
zero on every single atom in the observable universe, you

830
00:40:50,760 --> 00:40:52,400
would run out of atoms before you could write the

831
00:40:52,440 --> 00:40:52,840
number out.

832
00:40:52,880 --> 00:40:54,639
Speaker 2: It's beyond human comprehension.

833
00:40:54,719 --> 00:40:57,559
Speaker 1: Though. When that final supermassive black hole evaporates in a

834
00:40:57,719 --> 00:41:02,239
tiny flash of radiation, that is it the universe reaches

835
00:41:02,280 --> 00:41:06,159
its absolute final state maximum entropeak heat death. I try

836
00:41:06,199 --> 00:41:08,960
to visualize this with an analogy. Imagine a cup of

837
00:41:08,960 --> 00:41:12,599
hot coffee sitting on a desk in a perfectly sealed,

838
00:41:12,639 --> 00:41:16,760
perfectly insulated room. Okay, I'm picturing it. At first, you

839
00:41:16,800 --> 00:41:20,199
have a system with highly concentrated energy. The coffee is hot,

840
00:41:20,280 --> 00:41:22,559
the air in the room is cool. There is an

841
00:41:22,679 --> 00:41:27,320
energy gradient. You could theoretically use that temperature difference to

842
00:41:27,360 --> 00:41:29,239
do work like running a tiny stir.

843
00:41:29,119 --> 00:41:31,280
Speaker 2: Engine, right because heat wants to flow.

844
00:41:31,719 --> 00:41:34,960
Speaker 1: But over time, the heat from the coffee inevitably radiates

845
00:41:34,960 --> 00:41:37,679
into the cooler air. The coffee cools down, the air

846
00:41:37,719 --> 00:41:40,960
warms up just a tiny bit. Eventually the coffee in

847
00:41:41,000 --> 00:41:45,559
the room reached the exact same lukewarm temperature thermodynamic equilibrium,

848
00:41:45,599 --> 00:41:48,679
everything is the same temperature. Once that happens, nothing else

849
00:41:48,679 --> 00:41:51,880
can ever happen. The coffee will never spontaneously heat back up.

850
00:41:52,199 --> 00:41:54,800
The energy is evenly distributed, and the system is dead.

851
00:41:55,320 --> 00:41:57,719
Scale that room up to infinity, and that is the

852
00:41:57,719 --> 00:41:59,079
heat death of the universe.

853
00:41:59,440 --> 00:42:04,800
Speaker 2: It is a profound chilling concept, a completely featureless void

854
00:42:04,920 --> 00:42:08,679
of near zero energy. The photons and electrons left over

855
00:42:08,800 --> 00:42:12,320
from evaporated black holes and decayed protons are spread so

856
00:42:12,559 --> 00:42:15,320
infinitely far apart by the expansion of the universe that

857
00:42:15,360 --> 00:42:17,280
they will never ever interact.

858
00:42:16,880 --> 00:42:18,639
Speaker 1: Again, they'll never even builp into each other.

859
00:42:18,800 --> 00:42:21,239
Speaker 2: There is no structure, there is no energy gradient, There

860
00:42:21,280 --> 00:42:25,039
is no possibility for work, for heat, or for life.

861
00:42:25,119 --> 00:42:28,840
Speaker 1: The very concept of a system is fundamentally dead. Every

862
00:42:28,880 --> 00:42:31,400
atom that ever formed a star, a planet, or a

863
00:42:31,440 --> 00:42:35,199
human brain is dispersed into a uniformity so complete that

864
00:42:35,360 --> 00:42:38,199
no single region of the infinite void differs from any

865
00:42:38,199 --> 00:42:38,760
other region.

866
00:42:38,920 --> 00:42:42,280
Speaker 2: And that leads to a really wild philosophical realization about

867
00:42:42,280 --> 00:42:45,079
the nature of time itself. In physics, we measure the

868
00:42:45,079 --> 00:42:47,880
passage of time by the progression of entropy, by observing

869
00:42:48,000 --> 00:42:50,920
change that's happening. A glass shatters, a star burns, a

870
00:42:51,000 --> 00:42:52,280
clocktis right.

871
00:42:52,400 --> 00:42:55,840
Speaker 1: Time requires a sequence of events, a before and an after.

872
00:42:56,400 --> 00:43:00,400
But if the universe reaches maximum entropy, if absolutely nothing

873
00:43:00,440 --> 00:43:04,119
can change, if no energy gradient exists to allow even

874
00:43:04,159 --> 00:43:08,079
a single quantum event to occur. Ever, again, does time

875
00:43:08,159 --> 00:43:12,880
itself stop having any meaning? Can time functionally exist without change?

876
00:43:12,880 --> 00:43:16,639
Speaker 2: Mathematically, the dimension of time might still exist, But practically

877
00:43:16,679 --> 00:43:21,280
and physically, the arrow of time completely vanishes without change,

878
00:43:21,280 --> 00:43:23,920
without any measurable difference between the state of the universe

879
00:43:24,000 --> 00:43:25,800
right now and the state of the universe a trillion

880
00:43:25,880 --> 00:43:29,280
years from now time ceases to have any functional reality.

881
00:43:29,400 --> 00:43:30,239
Speaker 1: It's just frozen.

882
00:43:30,440 --> 00:43:34,719
Speaker 2: The universe simply is endlessly, unchangingly static. It is a

883
00:43:34,800 --> 00:43:36,599
permanent silent equilibrium.

884
00:43:36,639 --> 00:43:38,119
Speaker 1: Okay, let's take a deep breath.

885
00:43:38,239 --> 00:43:39,559
Speaker 2: Yeah, that was a heavy journey.

886
00:43:39,639 --> 00:43:42,320
Speaker 1: We have just traveled from right here, right now, all

887
00:43:42,320 --> 00:43:45,199
the way to the literal end of time. Let's concisely

888
00:43:45,239 --> 00:43:47,840
recap the mechanics of this journey we just took. We

889
00:43:47,920 --> 00:43:51,079
started with the Sun's core collapsing, triggering the violent shell

890
00:43:51,079 --> 00:43:54,039
burning and the helium flash ballooning the Sun into a

891
00:43:54,079 --> 00:43:56,480
red giant that boils Earth's oceans dry.

892
00:43:56,599 --> 00:43:57,920
Speaker 2: Then the gravity game started.

893
00:43:58,119 --> 00:44:01,920
Speaker 1: We explored how Jupiter's gravity slowly pumps Mercury's orbit through

894
00:44:01,960 --> 00:44:05,800
secular resonance, eventually turning the inner planets into chaotic, colliding

895
00:44:05,840 --> 00:44:09,440
billiard balls. We watch the dying Sun pulse and violently

896
00:44:09,480 --> 00:44:13,559
shed half its mass, creating a beautiful but deadly planetary nebula,

897
00:44:13,840 --> 00:44:16,239
while the weakened gravity lets the outer planets and the

898
00:44:16,320 --> 00:44:18,719
Orc Cloud simply drift away into the void.

899
00:44:18,960 --> 00:44:20,320
Speaker 2: And then the galaxy stepped in.

900
00:44:20,599 --> 00:44:24,039
Speaker 1: We face the terrifying galactic mechanics of the Andromeda collision

901
00:44:24,320 --> 00:44:28,119
and the immense tidal forces of Sagittarius TAZ stretching dead

902
00:44:28,159 --> 00:44:32,079
stars into atoms. And finally we track the absolute physical

903
00:44:32,119 --> 00:44:36,280
dissolution of baryonic matter, the evaporation of black holes via

904
00:44:36,320 --> 00:44:40,559
Hawking radiation, arriving at the completely featureless, unchanging void of

905
00:44:40,679 --> 00:44:41,559
maximum entropy.

906
00:44:41,719 --> 00:44:44,639
Speaker 2: It is a massive, crushing timeline. But bringing this massive

907
00:44:44,639 --> 00:44:47,920
scale back to you the listener right now, understanding the

908
00:44:48,000 --> 00:44:50,719
violent mechanics and the fleeting nature of the Solar system,

909
00:44:51,039 --> 00:44:53,199
it shouldn't be a source of existential despair.

910
00:44:53,320 --> 00:44:54,079
Speaker 1: No, not at all.

911
00:44:54,159 --> 00:44:57,239
Speaker 2: We are examining the extreme far ends of physics here,

912
00:44:58,199 --> 00:45:02,239
but the ultimate takeaway is per effective. It proves mathematically

913
00:45:02,320 --> 00:45:04,880
that this exact era we are living in, this incredibly

914
00:45:05,000 --> 00:45:09,480
narrow window of the universe's life span, where stars provide warmth,

915
00:45:09,679 --> 00:45:13,360
where complex chemistry can fold into DNA, and where conscious

916
00:45:13,400 --> 00:45:15,920
brains can actually look up and comprehend the physics of

917
00:45:15,960 --> 00:45:19,519
the cosmos. It is an unimaginably rare, precious moment.

918
00:45:19,840 --> 00:45:22,880
Speaker 1: The era of light and life is basically a microsecond

919
00:45:22,880 --> 00:45:25,559
flash in the span of an eternally dark universe, and

920
00:45:25,599 --> 00:45:28,880
that leaves me with one final lingering thought. The laws

921
00:45:28,880 --> 00:45:32,639
of thermodynamics guarantee that eventually we reach maximum entropy and

922
00:45:32,760 --> 00:45:35,239
nothing will ever happen again. It's a guarantee, But doesn't

923
00:45:35,239 --> 00:45:37,440
that make the fact that anything happen at all, The

924
00:45:37,480 --> 00:45:40,119
fact that gravity compressed a cloud of dust into a star,

925
00:45:40,519 --> 00:45:43,280
that planets formed, that life sparked, and that you are

926
00:45:43,280 --> 00:45:47,800
here right now listening to this a beautiful, mathematically profound miracle.

927
00:45:48,000 --> 00:45:50,679
Speaker 2: It is the ultimate triumph over chaos. We are the

928
00:45:50,760 --> 00:45:54,800
universe temporarily organizing itself, experiencing itself in a vibrant flash

929
00:45:54,840 --> 00:45:57,599
of order against a backdrop of eternal equilibrium.

930
00:45:57,719 --> 00:45:59,679
Speaker 1: So we want to know where you stand on this.

931
00:46:00,320 --> 00:46:04,079
Does knowing the ultimate irreversible physical fate of the universe

932
00:46:04,280 --> 00:46:08,360
make you feel incredibly insignificant in the grand chaotic machinery

933
00:46:08,360 --> 00:46:11,719
of gravity, or does it make this precise moment of

934
00:46:11,719 --> 00:46:15,719
your consciousness, this rare window of light, feel infinitely more valuable.

935
00:46:16,000 --> 00:46:17,960
What do you think about this timeline and the physics

936
00:46:18,039 --> 00:46:20,440
driving it? Leave a comment below and let us know

937
00:46:20,480 --> 00:46:21,159
your perspective.

938
00:46:21,559 --> 00:46:24,440
Speaker 2: The beauty of astrophysics is how it frames our own existence,

939
00:46:24,480 --> 00:46:28,079
and we always love reading how you process these massive concepts.

940
00:46:28,280 --> 00:46:30,400
Speaker 1: Thank you so much for joining us on this ultimate

941
00:46:30,440 --> 00:46:33,519
cosmic journey. This has been thrilling threads. Keep looking up,

942
00:46:33,599 --> 00:46:36,000
keep asking questions, and we'll see you next time.