Speaker 1: So right now, the solar system looks like this perfectly
ticking clock.
Speaker 2: Yeah, it really like you.
Speaker 1: Walk outside on a clear night, you look up and
everything just seems completely fixed. It seems permanent, right, balanced,
exactly perfectly balanced. But hidden in the really complex math
of gravity is this one percent chance that mercury will
just go completely rogue, which is terrifying, right, it could
cross the orbit of Venus and literally smash the inner
planets into dust. Yeah, and I mean this could happen
long before our sun even begins to die.
Speaker 2: Yeah, that's the crazy part.
Speaker 1: So that clockwork predictability that you see when you look
up it is, well, it's a temporary statistical illusion. Welcome
to thrilling Threads.
Speaker 2: It's great to be here for this one today.
Speaker 1: Our mission is to just completely unpack the chronological, scientifically
inevitable unraveling of our solar system and actually the entire universe.
Speaker 2: And we are not just talking about, you know what happens.
We're going to look under the hood at exactly why
it happens. Because if there's a central theme to this
entire journey we're taking you on today, a single unifying
force driving every single stage of this cosmic unraveling. It
is gravity, always, gravity always. Gravity is the ultimate engine
of both creation and destruction every phase of our universe's life,
from the ignition of the very first stars to like
the chaotic planetary billiards we'll talk about, all the way
down to the final black holes. Well, it's essentially a
story of gravity relentlessly trying to.
Speaker 1: Crush matter, and the universe just slowly running out of
ways to push back against it.
Speaker 2: Exactly. It's a losing battle.
Speaker 1: I love that framing, like gravity is this relentless, unavoidable crush,
and we are diving deep into the actual physics of
this today, drawing on literally centuries of astrophysical data.
Speaker 2: It's really fascinating sources.
Speaker 1: Yeah, spanning from the seventeen hundreds all the way to
recent supercomputer simulations. But we want to be really clear
right off the bat, yes, absolutely understanding this timeline. It
doesn't make our current lives meaningless, right, I think it
does the opposite, oh for sure.
Speaker 2: Like actually seeing the violent, chaotic mechanisms that dictate the
future makes the fact that you and I are here
right now having this conversation. It feels like a mathematical miracle.
Speaker 1: It really is a miracle, a statistical anomaly totally.
Speaker 2: So to understand how it all comes apart, I mean
we have to start at the center of our.
Speaker 1: Local neighborhood, the engine itself.
Speaker 2: The engine of our solar system, the Sun.
Speaker 1: Exactly, because the solar system doesn't die from an outside invasion.
Speaker 2: No alien lasers, right.
Speaker 1: No rogue black holes sweeping through at least not at first.
It dies from internal organ failure.
Speaker 2: Internal organ failure. Wow.
Speaker 1: Yeah. And to understand why the Sun will eventually destroy
the very planets it currently sustains, we have to look
at how it sustains them in the first place.
Speaker 2: Okay, let's unpack that.
Speaker 1: You mentioned gravity trying to crush everything. Right now, the
Sun is it's so incredibly massive that its own gravity
is trying to collapse it into a tiny, hyperdense sphere.
But it doesn't collapse, no, because it's fighting back. And
this takes us back to Arthur Eddington's proposals. This was
in nineteen twenty, right about nuclear fusion.
Speaker 2: Yes, Eddington was a pioneer there.
Speaker 1: The Sun is essentially just a gigantic, continuous nuclear explosion.
I mean, it's taking hydrogen atoms smashing them together in
the core at what fifteen million degrees.
Speaker 2: About fifteen million degrees celsius, yes.
Speaker 1: And fusing them into helium.
Speaker 2: And that fifteen million degrees is the critical number because
you know, atoms don't want.
Speaker 1: To touch, right, electrostatic repulsion exactly.
Speaker 2: That temperature is required to overcome the electrostatic repulsion of
the hydrogen nuclei. They repel each other violently.
Speaker 1: But the heat and pressure force them together anyway.
Speaker 2: Right, And when they finally fuse, they release an incredible
amount of energy in the form of photons light, light
and heat. But those photons, they don't just straight out
into space.
Speaker 1: This is the part that blew my mind when I
was reading this source material.
Speaker 2: It's so counterintuitive. The core of the Sun is so
unimaginably dense that a single photon of light created in
that fusion reaction. It undergoes what physicists call a random walk.
Speaker 1: A random walk because it keeps crashing into things constantly.
Speaker 2: It bounces off atoms, gets absorbed, gets re emitted, ping
ponging constantly, just zigzagging in this incredibly dense plasma trap
for a very long time. Yes, it can take upwards
of one hundred thousand years for that single photon to
finally push its way from the core to the surface
of the Sun.
Speaker 1: Wait wait, so okay, think about this. The sunlight hitting
your face right now, if you're standing outside listening to this,
that light was actually generated in the core of the
Sun one hundred thousand years ago. That's right, like during
the place to see an epoch. While early humans were
I don't know, discovering fire, the Sun was making the
light that's hitting us today. That is absolutely statd.
Speaker 2: It really messes with your sense of time. And all
of those ancient photons pushing their way out, they create
what we call radiation pressure, the outward push. Yes, this
outward pressure perfectly balances the inward crush of gravity. Physicists
call this hydrostatic equilibrium.
Speaker 1: Hydrostatic equilibrium.
Speaker 2: It's a beautiful, delicate standoff, just gravity pushing in, light
pushing out. But here is the problem.
Speaker 1: The gas tank is in bottomless exactly.
Speaker 2: The ammunition for that outward push is finite. The Sun
has a limited supply of hydrogen in its core, and
it is already about four point six billion years into
that supply, so it's middle aged very much. So it
has roughly five billion years of hydrogen fuel remaining.
Speaker 1: Which sounds like a really long time to us. But
what fascinates me is the mechanism of what happens when
the tank actually runs dry. It's not what you'd expect,
not at all because intuitively, you know, if a fire
runs out of fuel, gets smaller, it fades away into embers.
But the Sun does the exact opposite. It becomes a
red giant. It swells up massively to swallow the inner planets.
So why does running out of fuel make the star
get physically bigger?
Speaker 2: That is the brilliant, sort of cruel counterintuition of stellar mechanics.
When the core runs out of hydrogen.
Speaker 1: Fusion stops, the engine cuts out, yes.
Speaker 2: And suddenly that outward radiation pressure, all those photons fighting
their way out that we just talked about, that pressure
drops significantly.
Speaker 1: And gravity doesn't take a break.
Speaker 2: Never without that outward pressure, gravity instantly starts winning the
tug of war. The core begins to collapse inward.
Speaker 1: So the core does actually shrink at first.
Speaker 2: The core shrinks, yes, it compresses, but remember your basic thermodynamics.
When you compress a gas, what happens?
Speaker 1: It heats up exactly.
Speaker 2: As the dead helium ash core is crushed by gravity,
its temperature skyrockets. Now surrounding this dead, shrinking core is
a shell of hydrogen gas.
Speaker 1: Gas that previously wasn't quite hot enough to fuse.
Speaker 2: Right, right, It was just sitting there.
Speaker 1: Yeah.
Speaker 2: But as the collapsing core superheats from the compression, it
acts like an incredibly powerful stove burner, oh wow, and
it ignites that surrounding shell of hydrogen.
Speaker 1: So the fusion moves from the center to like a
ring around the center. They call it shell burning.
Speaker 2: Precisely shell burning. And this new phase is far more
vigorous and completely uncontrolled compared to the stable core fusion
we have today.
Speaker 1: BIG's a hotter, much hotter.
Speaker 2: The energy output spikes massively. This new intense outward pressure
from the shell overwhelms gravity in the outer layers of.
Speaker 1: The star, so the outside gets pushed away, right.
Speaker 2: It pushes the Sun's outer plasma envelope incredibly far out
into space.
Speaker 1: It's like it's like a pressure cooker where the internal
thermostat completely breaks.
Speaker 2: That's a great analogy, Like instead.
Speaker 1: Of safely releasing steam, the pressure just builds exponentially in
the outer layers until the whole apparatus balloons outwards. Yes,
it inflates, and as it balloons, the surface actually cools
down a bit, right, which is why it shifts on
the light spectrum and turns red. A red giant exactly.
Speaker 2: The surface is cooler, but the total heat output is monstrous.
Speaker 1: And the physical physical size of it is terrifying. The
outer atmosphere of the Sun will expand so far that
it will physically engulf the orbit of mercury swallowed whole.
Then we'll reach out and just completely swallow venus.
Speaker 2: The sheer inevitability of it is what astrophysicists find so profound.
There is no stopping that core collapse, and therefore no
stopping the expansion. It's built into the physics.
Speaker 1: Now, I've read conflicting models about Earth, specifically, like some
say the Sun's physical plasma will actually reach Earth's orbit
and swallow us too.
Speaker 2: Yes, that's one model.
Speaker 1: And then some say the Sun loses enough mass during
this phase that Earth's orbit gets pushed back just enough
to avoid physical contact.
Speaker 2: Also a valid mathematical possibility, But.
Speaker 1: Honestly, looking at the physics we're talking about, that debate
feels entirely academic, Like it doesn't matter if we get
physically touched by the plasma, does it.
Speaker 2: It is entirely academic, because long before the physical boundary
of the Sun reaches our orbital distance, its luminosity, its
actual heat output will have increased by a factor.
Speaker 1: Of thousands, thousands of times brighter.
Speaker 2: Yes, you are no longer dealing with a warm, stable
star ninety three million miles away. You are dealing with
an angry wall of plasma taking up half the daytime sky.
Speaker 1: The heat alone is just a total reset button. I mean,
we are talking about the oceans boiling away into.
Speaker 2: Space, completely evaporating, the.
Speaker 1: Atmosphere being violently stripped off by these massive stellar winds.
The very crust of the Earth, like the tectonic plates,
the mountains, every single rock, yeah, every fossil, every single
trace of human history, just melting into an ocean of
glowing liquid rock. Like everything is sterilized.
Speaker 2: The concept of survival in any localized sense is completely
eradicated by the thermodynamics involved here.
Speaker 1: No underground bunker is going to save you, not a chance.
Speaker 2: You aren't just dealing with a severe climate shift. You
are dealing with the physical state of the entire planet's
surface transitioning from solid.
Speaker 1: To liquid, which is horrifying. Yeah, but as terrifying as
that red giant phase is for us on Earth, what
is happening deep inside the core of the Sun at
that exact moment is even more violent. Oh.
Speaker 2: Absolutely, the surface is just a symptom, right.
Speaker 1: The Sun doesn't just sit as a red giant forever.
It's actually building toward a massive internal detonation, the helium flash.
This is one of the most extreme events in stellar evolution,
and again, gravity is the main culprire here.
Speaker 2: Okay, take us into the core.
Speaker 1: Remember that dead core of helium ash we talked about,
the one that shranks. It's a stove burner, right, Well,
it is continually being crushed by the immense weight of
the expanding star above it. It gets denser and denser
and hotter and hotter.
Speaker 2: Because gravity won't quit exactly, but it doesn't behave like
normal gas anymore.
Speaker 1: Under that kind of pressure.
Speaker 2: It enters this bizarre state governed by quantum mechanics, which
we call electron degeneracy.
Speaker 1: Okay, let's unpack electron degeneracy because this is where the
physics gets ritibly weird.
Speaker 2: Very weird.
Speaker 1: Normally, if you heat up a gas, it expands, which
cools it down. It's like a natural safety valve built
into the.
Speaker 2: Universe and negative feedback loop.
Speaker 1: Yes, but in this core, the atoms are packed so
tightly together that the poly exclusion principle kicks in.
Speaker 2: Yes, exactly, the poly exclusion principle. It's a quantum rule
stating that two identical fermions like electrons, for example, they
cannot occupy the exact same quantum state simultaneously.
Speaker 1: It can't sit in the same seat in the theater.
Speaker 2: Good way to put it. Gravity has crushed this helium
core so densely that all the available lower energy sets
so to speak. For the electrons are completely filled, so
they're jammed in. They are locked in place. The pressure
holding the core up against gravity is no longer thermal
pressure from heat. It is entirely quantum mechanical pressure.
Speaker 1: And why is that dangerous for the star? Why does
that cause an explosion?
Speaker 2: Because it breaks that safety valve you mentioned ooh. In
a normal gas, if the temperature goes up, the gas
expands and cool down. But in degenerate matter, the pressure
is completely disconnected from the temperature, so it can get
hotter without expanding exactly, So as gravity continues to crush
the core, the temperature rises towards a staggering one hundred million.
Speaker 1: Degrees one hundred million, and at one.
Speaker 2: Hundred million degrees, the helium finally ignites. It starts fusing
into carbon.
Speaker 1: But because it's degenerate matter, the core can't expand to
cool itself down exactly.
Speaker 2: The helium ignites, releasing massive amounts of heat. That heat
makes the fusion reaction happen even faster, which releases even
more heat, which makes the reaction even faster.
Speaker 1: It's a runaway loop.
Speaker 2: It is a runaway thermonuclear detonation.
Speaker 1: Yeah.
Speaker 2: Martin Schwartz's calculations back in nineteen fifty two really illuminated
how violent this is.
Speaker 1: Yeah, the numbers from Schwartz are insane.
Speaker 2: In a matter of minutes, literally minutes, the entire core
of the Sun undergoes this helium flash.
Speaker 1: Min it's the whole star.
Speaker 2: Yes, for that brief window, the core generates more power
than the combined output of every single star in the
entire Milky Way galaxy.
Speaker 1: That is just unfathomable to me. A galactic level explosion
contained entirely within the core of our Sun.
Speaker 2: And it's buried so deep inside the star that it
doesn't blow the Sun apart entirely, but it violently restructures
the inside.
Speaker 1: The Sun survives, it barely.
Speaker 2: It survives, but it enters what astrophysicists call the horizontal
branch phase.
Speaker 1: And what strikes me here is that this is the
moment the Sun fundamentally transitions, like it goes from being
the stable anchor for five billion years into a wildly
erratic dyeing machine. It's running on fumes, right. It starts
burning through successive heavier fuels than these desperate violence spasms.
Speaker 2: It's the cruel irony of stellar evolution. A dying star
does not fade gently into the night because healum fusion
is highly inefficient compared to hydrogen. This phase only lasts
about one hundred million.
Speaker 1: Years, which is a blink of an eye for a star, a.
Speaker 2: Fraction of its life. The Sun is essentially consuming itself
from the inside out in a series of shorter and
increasingly violent reactions.
Speaker 1: So any of the outer planets Jupiter, Saturn, Uranus, Neptune
that managed to survive the initial red giant expansion they
are now orbiting a star that is essentially having a
sustained internal seizure.
Speaker 2: Its mass is shifting, its energy output is erratic.
Speaker 1: Which perfectly sets up the next mechanism of destruction we
need to talk about. Because as the central anchor of
our solar system starts acting erratically, the gravitational bonds holding
the planets in their lanes, they begin to fray.
Speaker 2: And this brings us to one of the most unnerving
realizations in modern astrophysics. I think, Yeah, the seeds of
our solar system's destruction are not just in the Sun dying.
They are actually already planted in the gravitational relationships between
the planets themselves.
Speaker 1: Right now, Okay, this is where I want to push
back on the timeline a bit. Yeah, because Jacques Lascar's
two thousand and nine study at the Paris Observatory is
widely cited here. Yes, a landmark study. He ran thousands
of simulations on supercomputers basically trying to solve the n
body problem for the Solar system, right.
Speaker 2: Tracking the g gravitational influence of everything on everything else.
Speaker 1: And he found a roughly one percent probability that Mercury's
orbit completely destabilizes within the next five billion years, triggering
a massive chaotic cascade.
Speaker 2: Yes, the planetary billiards.
Speaker 1: Well, wait, we know from chaos theory that the n
body problem is inherently unpredictable over long time scales.
Speaker 2: It's highly sensitive to initial conditions.
Speaker 1: Right, A butterfly flapping its wings alters the gravitational math
millions of years down the line. So how can LASCAR
definitively claim a one percent chance of total chaos five
billion years from now when we can't perfectly predict planetary
positions even a few million years out.
Speaker 2: It's a really good point.
Speaker 1: Aren't these models fundamentally limited by that chaos?
Speaker 2: That is exactly the right question to ask, and it
actually highlights the genius of lascar's approach to this problem.
You are absolutely correct that we cannot predict the exact
position of mercury five.
Speaker 1: Billion years from now. It's physically impossible.
Speaker 2: Yes, the chaos makes specific positional prediction impossible. But Lescar
wasn't looking for exact positions. He was modeling the statistical
envelope of orbital evolution. The envelope, okay, by running thousands
of slightly varied initial conditions. He wasn't predicting, you know,
where mercury would be on a specific Tuesday, five billion
years from now. He was calculating the boundary conditions of
its orbit over time. And what he found was that
the chaotic variations aren't just random, harmless noise.
Speaker 1: It compound.
Speaker 2: They compound in a very specific, dangerous way due to
a mechanism called secular resonance.
Speaker 1: Secular resonance, I love that term. This is the mechanism
that basically turns a tiny little wobble into a full
on planetary collision. How does that actually work? In physical terms?
Speaker 2: Think of it like pushing a child on a swing. Okay,
if you push at random times, sometimes when the swing
is coming out you sometimes when it's moving away, the
swing doesn't go very high. The energy cancels.
Speaker 1: Out right, you just mess up their momentum.
Speaker 2: But if you push at the eggs exact same point
in the arc every single time, if you match the
resonant frequency of the swing, you are pumping energy into the.
Speaker 1: System and the child goes higher and higher.
Speaker 2: Exactly.
Speaker 1: Yeah.
Speaker 2: In our solar system, Jupiter is the one doing the pushing.
Speaker 1: Because Jupiter is just so massive it dominates the gravitational landscape. Right.
Speaker 2: It's the bully of the Solar System. And while Jupiter
and Mercury are incredibly far apart, they're orbital perihelions. The
points where they are closest to the Sun gradually rotate
around the Sun. Over millions of years.
Speaker 1: The whole oval shape of the orbit slowly.
Speaker 2: Spins, yes a psidal procession. Laskar showed that there is
a chance these rotations will synchronize. Oh wow, Jupiter's massive
gravity will start delivering a tiny, consistent gravitational tug to
Mercury at the exact same relative point in its orbit
millions of times over.
Speaker 1: So Jupiter is perfectly timing its pushes on the swing exactly,
and instead of making Mercury go higher, it stretches Mercury's orbit.
It changes it from a relative circular path into an
extreme oval. It increases its orbital eccentricity.
Speaker 2: Jupiter is literally pumping angular momentum into Mercury's orbit. Year
after year, eon after eon, Mercury's path gets more and more.
Speaker 1: Elliptical, it gets stretched thinner and thinner.
Speaker 2: And here is where the one percent probability becomes a
terrifying reality. In a cosmic time frame. One percent isn't.
Speaker 1: A long shot, it's an inevitability.
Speaker 2: It's a guarantee waiting to happen. Time is the ultimate multiplier.
If Mercury's orbit stretches far enough, its path crosses the orbit.
Speaker 1: Of Venus, and once that happens, I mean the entire
Inner Solar System turns into a chaotic game of planetary billiards.
Speaker 2: All bets are off.
Speaker 1: It's no longer just a slow, gentle gravitational tug its
massive planetary bodies having near misses, and near misses in
space are catastrophic because they warp orbits instantly.
Speaker 2: They trade huge amounts of momentum.
Speaker 1: The simulation show Mercury just being flung straight into the
Sun or even ejected from the Solar System in times
kicked out into the void. Yeah, and even worse, the
gravitational shockwaves of Mercury running wild through the Inner System
could destabilize Earth. The model show Venus in Earth could
physically collide.
Speaker 2: The profound takeaway here, I think is that no external
force is required. You don't need a giant rogue asteroid
to hit us. You don't need some sci fi alien
death ray. The exact mathematical equations that keep our planets
in this beautiful stable dance. Today, they contain the strict,
unavoidable conditions of their own collapse.
Speaker 1: It's baked into the math.
Speaker 2: The Solar system is inherently self destructive over deep time.
Speaker 1: I always pictured it like a spinning top on a table.
Like if you watch it for a few seconds, it
looks perfectly still, solid and completely stable, get straight up.
But that stability is entirely dependent on its momentum. The
second it loses just a fraction of a percent of
that momentum, it begins.
Speaker 2: To wabble, And once the wobble starts.
Speaker 1: It violently crashes almost immediately. We are just living in
the brief window where the top looks perfectly still.
Speaker 2: That is a brilliant analogy. The wobble is coming. And
remember this gravitational destabilization of the planets is happening at
the exact same time the Sun is entering its most
violent erratic phase.
Speaker 1: Right. The timing is awful.
Speaker 2: The asymptotic giant branch or AGB phase.
Speaker 1: Right, So we have planets potentially playing demolition derby with
each other, and meanwhile, the central star, the Sun is
throwing the ultimate.
Speaker 2: Tantrum a total meltdown.
Speaker 1: Well. Dan Patchiski theorized this back in nineteen sixty six.
During this AGB phase, the Sun doesn't just quietly burn
one fuel. It has these alternating shells of hydrogen and
helium that ignite and extinguish around the core like a
sputtering engine. And it's not a smooth transition. These are
massive thermal pulses.
Speaker 2: The physical mechanics of a thermal pulse are staggering to
think about. A shell of helium ignites, generating intense heat,
which forces the outer layers of the Sun to expand massively.
It balloons up again, but as it expands, it cools down.
The heat reaction gets choked out and gravity pulls everything rapidly.
Speaker 1: Back inwards, so it shrinks back down.
Speaker 2: Then the hydrogen shell ignites again, building up more helium ash,
until the whole cycle repeats.
Speaker 1: Yeah, every one.
Speaker 2: Hundred thousand years or so, the Sun swells up and contracts.
Speaker 1: Violently expanding and shrinking.
Speaker 2: And this lasts for roughly a million years.
Speaker 1: Think about the gravitational whiplash that causes for everything orbiting it.
We just talked about how a tiny consistent tug from
Jupiter can completely ruin Mercury's orbit a tiny tug. Yes, Now,
imagine the central anchor of the entire Solar system radically
changing its physical size and its gravitational influence every one
hundred thousand years. The entire system is effectively being shaken
like a snow globe.
Speaker 2: It is catastrophic, especially for the outer Solar system. Consider
the Kuiper belt.
Speaker 1: It comments out past Neptune right.
Speaker 2: Billions of icy comets and dwarf planets out there. They're
only loosely bound by the Sun's gravity to begin with,
to just barely hang it on. So when the Sun
pulses and its mass distribution shifts like that, those delicate
gravitational tethers snap, they just break. The Kuiper bell is
completely destabilized. Trillions of icy bodies are thrown out of
their orbits. The Solar system becomes this chaotic shooting gallery
with comets raining inward.
Speaker 1: It's apocalyptic. But the Sun isn't just pulsing, It's actively disintegrating, yes,
shedding its layers. And this leads us to one of
the most paradoxical phenomena in astrophysics. I think in seventeen
sixty four, Charles Messier cataloged this glowing shell of gas.
Speaker 2: In space a beautiful discovery.
Speaker 1: He didn't realize it at the time, but he was
looking at a planetary nebula, which is the exact fate
awaiting our own Sun.
Speaker 2: During these violent agb thermal pulses, the outward pressure is
so intense, and the outer layers of the Sun are
pushed so far away from the core that gravity simply
cannot hold onto them anymore.
Speaker 1: It just lets go.
Speaker 2: The Sun begins to shed its mass. It expels these
massive waves of plasma out into space via stellar winds,
and these winds are traveling at ten tens of kilometers
per second. Over this entire phase, the Sun will lose
up to fifty percent of its total mass.
Speaker 1: Half of the Sun's mass is blown away into the void,
like blowing the dandelion seeds into the wind.
Speaker 2: Yes, and as those outer layers are completely stripped away,
the unimaginably hot exposed core of the dying stars finally
revealed the naked core. This core is emitting massive amounts
of intense ultraviolet radiation, and that UV radiation hits the
expanding shells of expelled gas, ionizing the atoms and causing
them to glow brilliantly in.
Speaker 1: All those vibrant reds, blues, and greens. Exactly. This is
the paradox I'm talking about. Because we've all seen these
images from the Hubble or James Webb telescopes. Oh, they're iconic,
the Cat's eye nebula, the ring nebula. They are literally
the most breathtaking, beautiful, colorful images of space we have.
People have them on dorm room posters. They're gorgeous, but
when you actually understand the physics, it is incredibly macabre.
You are looking at a planetary graveyard, a crime scene. Yeah,
the beautiful glowing gas is the evaporated atmosphere of a
dying star, and buried inside that light is a chaotic
maelstrom of destroyed planets. It's true like alien astronomers in
a distanced oar system might look at our Sun in
five billion years see a gorgeous, glowing ring of color
through their telescopes and have no idea. They are looking
at the absolute erasure of Earth and everything we ever were.
Speaker 2: It perfectly encapsulates the indifference of the universe, doesn't it.
Cosmic destruction is often esthetically.
Speaker 1: Magnificent, beautiful, but deadly, But the.
Speaker 2: Physical consequences for our Solar System during this mass shedding
phase are permanent, because as the Sun loses half its mass,
its gravitational grip on the remaining planets completely weakened.
Speaker 1: This is the great dispersal, like an aging king losing
his empire. If you weaken the gravity holding the planets
in their orbits have to expand they just drift outward.
Jupiter might drift from its current five astronomical units out
to ten. Neptune might be pushed so so far out
that the Sun's weakened gravity can't hold it at all,
and it just slips its leash entirely. It becomes a
rogue planet, just drifting alone in interstellar space. The Solar
System is a structured, cohesive unit is just completely disassembled.
Speaker 2: The ties that mine the system together are entirely suvered.
And what is left behind, You know, once that beautiful
glowing nebula of gas finally expands and dissipates into the
interstellar medium, what sits at the center of the graveyard
the ultimate corpse.
Speaker 1: A white dwarf astronomer Walter Adams confirmed their existence in
nineteen fourteen. By looking at the companion, start serious, and
the physical reality of a white dwarf just completely breaks
the brain.
Speaker 2: It's hard to visualize.
Speaker 1: After the Sun sheds its utter layers, all that remains
is that dead carbon oxygen core we talked about earlier.
It contains roughly half the mass of our original Sun,
but it has been crushed by gravity into a sphere
the size of the Earth.
Speaker 2: Think about that density for a second. You're taking fifty
percent of the Sun's mass, hundreds of thousands of times
the mass of the Earth and packing it into a
volume no larger than our planet.
Speaker 1: It's insane.
Speaker 2: A single teaspoon of white dwarf material would weigh several
tons on Earth a teaspoon. And again, it is held
up entirely by electron degeneracy pressure.
Speaker 1: The quantum seeds are full, exactly.
Speaker 2: Yeah, the quander resistance of electrons is the literal only
thing preventing it from collapsing entirely into a black hole.
Speaker 1: And it is searingly hot, like one hundred thousand degrees
celsius on the surface. Yeah. But here's the key, the
really sad part. There is no fusion.
Speaker 2: The engine is dead.
Speaker 1: It is no longer creating any new energy.
Speaker 2: It is simply a massively hot rock radiating its residual
thermal energy into the absolute zero vacuum of space.
Speaker 1: It's exactly like pulling a glowing red hot coal out
of a campfire. Yeah, it's incredibly hot to the touch,
and it glows brightly, but there is no chemical reaction
happening inside it anymore. Right, it's just cooling. It is
just slowly, inevitably giving up its heat to the cold
air of the forest. Except for this white dwarf, the
forest is the entire universe, and the cooling process takes
a timescale that makes the age of the universe look
like a rounding error.
Speaker 2: This is where we have to fundamentally adjust how we
perceive time. A white dwarf cools solely through thermal radiation.
Speaker 1: Just bleeding heat into the dark. Right.
Speaker 2: It has a massive amount of stored heat and a
relatively very small surface area to radiate it from, so
it cools imperceptibly slowly. It transitions from white to yellow
to red over trillions of years.
Speaker 1: And eventually it goes completely dark. It becomes a black dwarf, Yes,
a frozen lightless cinder at the exact temperature of the
cosmic background radiation. But here is the detail from our
sources that literally made me stop reading.
Speaker 2: Oh, I know which one you mean.
Speaker 1: We talk about black drfs as the final state of
a star, but the time required for white dwarf to
cool down into a black dwarf is estimated to be
roughly a quadrillion years.
Speaker 2: A quadrillion ten to the fifteenth power.
Speaker 1: That's a one followed by fifteen zeros. The universe itself
is only thirteen point eight billion years old. The universe
is practically a newborn baby compared to the time it
takes to make a black dwarf. It's barely started. So currently,
right now, in the entire infinite expanse of the cosmos,
not a single black dwarf exists. Reality has been around
long enough to make even one.
Speaker 2: It is a profound realization. Everything we observe in the
night sky right now, every galaxy, every quasar, every supernova,
it all represents the chaotic, fiery infancy of the universe.
Just the opening credits, the vast overwhelming majority of the
universe's lifespan will actually be spent in the dark populated
exclusively by these invisible black dwarfs.
Speaker 1: Now, I have to ask the skeptics question here go
for it. If the universe isn't even old enough for
a single black dwarf to exist, how can physicists speak
with such absolute certainty about a timeline a kadrillion years away?
Speaker 2: That's fair?
Speaker 1: Are we not assuming that our current understanding of thermodynamics
will just hold up indefinitely? Like what about quantum fluctuations
or proton decay generating residual heat? How are we so?
Speaker 2: You are referencing the very deepest edges of theoretical physics. There,
it is true that on a timescale of a quadrillion years,
extremely rare quantum events become statistically probable. However, the macro
cooling of a macroscopic object like a white dwarf is
governed by the rigid, unbreakable laws.
Speaker 1: Of thermodynamics entropy.
Speaker 2: Yes, while quantum fluctuations might provide incredibly tiny, localized spikes
of energy, they cannot overcome the macroscale thermodynamic imperative of entropy.
Heat flows from warmer to colder period.
Speaker 1: The house always wins.
Speaker 2: The house always wins. The white dwarf must cool the
physics of radiation in a vacuum is ironclad, irrespective of
whether the universe is fourteen billion or a quadrillion years old.
Speaker 1: It's unavoidable. And while that central ember is spending a
quadrillion years just cooling off, the extreme outer edges of
our Solar system are meeting their own silent, invisible end.
Yes the final dispersal. In nineteen fifty yan or It
mapped out the map mathematics of the Oort Cloud, this
massive spherical shell of trillions of icy comets enveloping the
whole Solar System.
Speaker 2: These objects are incredibly distant. We're talking distances up to
one hundred thousand times the distance between the.
Speaker 1: Earth and the Sun, way way out there.
Speaker 2: At that range, the Sun's gravity is incredibly weak. It
is barely a whisper holding these comets in orbit.
Speaker 1: And since the Sun lost half its mass during the
planetary nebula phase, that whisper fades completely. Gravitational tether is
just broken. It snaps those trillions of comets, these priskine
frozen time capsules from the very formation of the Solar
System four point six billion years ago. They simply let go.
They untethered, They aren't thrown violently. Like the inner planets,
they just drift away to the interstellar foid in total silence,
over billions of years. Passing stars and galactic tides will
just sweep them up. The outer boundary of our home
is just erased.
Speaker 2: It is a quiet dissolution, a slow fade out. But
while our immediate neighborhood is freezing and drifting apart the
macro environment, the galaxy itself is preparing a much much
more violent fate for whatever remains of our dead system.
Speaker 1: This is the part of the timeline I like to
call double Jeopardy, good name for it, because we've been
completely focused on our son's internal mechanisms. But if we
zoom out to the galactic scale, we are on a
collision course, a literal physical collision course, with the Andromeda galaxy.
Speaker 2: In twenty twelve, incredibly precise measurements from the Hubble Space
telescope confirmed the exact vector and velocity of Andromeda.
Speaker 1: It's head and right for us.
Speaker 2: It is a massive spiral galaxy, larger than our Milky Way,
and it is hurtling toward us at roughly one hundred
and ten kilometers per.
Speaker 1: Second, and the timing is practically a cosmic joke. The
collision is slated to begin in approximately four point five
to five billion years.
Speaker 2: Which perfectly coincides.
Speaker 1: It perfectly coincides with our son running out of hydrogen
and expanding into a red giant. So while our sun
is violently bowling the oceans and swallowing venus, the entire
night sky above that dying sun is going to be
filled with the approaching spiral arms arms of an alien galaxy.
Speaker 2: It is two completely separate catastrophes unfolding at the exact
same time.
Speaker 1: The visual of that sky would be terrifyingly majestic, which
is this massive, glowing spiral taking up the whole field
of view. But let's look at the physics of a
galactic merger, because it's highly counterintuitive, right it.
Speaker 2: Is when two galaxies collide, the stars themselves almost never
actually hit each other.
Speaker 1: Wait really, with billions of stars, yes.
Speaker 2: The space between stars is so unfathomably vast that the
two galaxies essentially pass through one another like ghosts.
Speaker 1: Right, It's not a demolition derby of stars physically smashing
together like cars. It's a gravitational war.
Speaker 2: Exactly, the sheer mass of these two galaxies interacting creates
monstrous tidal forces. It is a process that takes one
to two billion years to fully.
Speaker 1: Settle a billion year car crash.
Speaker 2: As the galaxies pass through each other, swing back around,
and merge into a single elliptical galaxy, what astronomers playfully
call milk comeda. Milk comeda, the gravitational feels are wildly chaotic.
Stars are violently ripped from their ancestral orbits.
Speaker 1: And where does our dying solar system, or what's left
of it, end up in this new Milkomata galaxy.
Speaker 2: The simulations show it is largely a roll of the dice.
We could be caught in a massive tidal tale and
flung out into the extreme outer edges of the new.
Speaker 1: Galaxy, cast out into the dark.
Speaker 2: Cast into the lonely intergalactic halo.
Speaker 1: Yes.
Speaker 2: Or conversely, we could lose orbital angular momentum and be
dragged deep into the chaotic, dense new core of the
merged galaxy.
Speaker 1: And if we get dragged into the core, we meet
the final boss of gravitational destruction, Sagittarius.
Speaker 2: A the Monster in the middle.
Speaker 1: In nineteen seventy four, Bruce Bailick and Robert Brown detected
a powerful radio source at the center of the Milky Way,
which we now know is a supermassive black hole. It
contains the mass of roughly four million.
Speaker 2: Suns, and Andromeda has an even larger supermassive black hole
at its center. During the merger, these two supermassive black
holes will eventually spiral in toward each other and merge.
Speaker 1: Sending massive gravitational waves rippling through space.
Speaker 2: Time exactly, the new combined supermassive black hole will completely
dominate the center of Milcomato.
Speaker 1: Currently, we orbit the galactic center at a very safe
distance of about twenty six thousand light years, but orbits
are not eternal. This is another mechanism we need to unpack.
Orbit'll decay, yes nothing orbits forever over tens of billions
of years, moving through the interstellar medium, interacting gravitationally with
passing stars and emitting tiny amounts of energies gravitational ways,
our orbit around the galactic center will inevitably shrink. We
will spiral inward.
Speaker 2: It is a slow, agonizing drag, and as are dead
frozen black dwarf of a sun is pulled closer and
closer to the central supermassive black hole, the environment turns
fiercely hostile.
Speaker 1: It gets crowded.
Speaker 2: The stellar density near the core is immense. Stars are
whipping around the black hole at velocities exceeding ten thousand
kilometers per second.
Speaker 1: And if if our dead sun gets too close to
the black hole, it doesn't just quietly fall in, does it.
It gets shredded by the tidal forces. The mechanism here
is called spaghettification.
Speaker 2: I know it sounds like a good joke.
Speaker 1: It sounds hilarious that the physics are completely brutal.
Speaker 2: The gravitational ingradient of a supermassive black hole is so
steep that the force of gravity changes drastically over very
short distances.
Speaker 1: What does that mean for an object falling in?
Speaker 2: If our dead sun approaches the black hole, the gravitational
pole on the side of the Sun facing the black
hole is vastly measurably stronger than the pole on the
far side.
Speaker 1: So the front of the star is being yanked way
harder than the back of the star. It physically stretches
the object, yes, and.
Speaker 2: It compresses it from the sides simultaneously. The tidal forces
simply overwhelm the sheer structural integrity of the carbon oxygen dwarf.
Speaker 1: He just rips it apart.
Speaker 2: The dead star and any frozen planetary remnants still clinging
to it are literally ripped apart into a stream of
superheated plasma.
Speaker 1: They are stretched into an infinitesimally thin river of atoms,
spiraling down the accretion disk and eventually crossing the event horizon.
Gone forever to go back to our central thesis, Gravity
always wins. It crushes the Sun, It destabilizes the planets,
It merges the galaxies, and eventually the supermassive black hole
at the center acts as the ultimate cosmic vacuum cleaner.
Speaker 2: Gravity is relentless. It's the ultimate eraser. But what if
we consider an.
Speaker 1: Escapee ooh, an escapey okay.
Speaker 2: Let's imagine a scenario where the chaotic merger of the
galaxies flung our dead Sun entirely out of the galaxy
into the deep intergalactic void.
Speaker 1: So we missed the black hole, entirely.
Speaker 2: Safe from the black hole, safe from collisions.
Speaker 1: Safe isolated, and just floating in the dark forever. Except well,
forever is where physics draws a hard line.
Speaker 2: It certainly does, because even.
Speaker 1: If a single atom of Earth manages to survive the
Sun's death, survive the planetary billiard, survive the galactic collision,
and completely escape the black hole it still face. This
is the ultimate inescapable law of reality, the end of everything.
Speaker 2: We are talking about the concept of universal heat death,
and this brings us to the physicist William Thompson Lord
Kelvin back in eighteen fifty one, the thermodynamics guy. He
formulated this based on the second law of thermodynamics, which
states that in any closed system, and the universe is
the ultimate closed system, entropy always increases.
Speaker 1: Entropy basically being the measure of disorder, or more accurately,
the dispersal of energy exactly.
Speaker 2: Energy inevitably moves from concentrated usable forms like the hot
core of a star, into diffuse, unusable forms like ambient
heat radiating into empty space.
Speaker 1: Hot objects cool down.
Speaker 2: Highly structured things like galaxies or planets or biological life
eventually decay into disorder, and this process is a one
way street. You cannot unburn a log of wood.
Speaker 1: Once the heat is gone, it's gone. So let's map
out this final timeline. Because the numbers here completely break
the human ability to comprehend scale.
Speaker 2: They are absurd numbers.
Speaker 1: We are long past the era of black dwarfs. We
are looking at ten to the fourteenth power years into
the future.
Speaker 2: At that point, the degenerate era begins. Star formation has
completely ceased.
Speaker 1: No new stars are being born.
Speaker 2: The universe has expanded so much, and the remaining hydrogen
gas is spread so incredibly thin that gravity can no
longer pull it together to ignite new stars. The last
slow burning red dwarf stars flicker out, the lights go out.
The universe goes completely dark. It is populated exclusively by
stellar corpses, white dwarfs, neutron stars, and black holes.
Speaker 1: Just a cemetery of dead stars drifting further and further
apart as the universe continues to expand. But even those
corpses aren't internal. No, they aren't. Let's fast forward to
ten to the fortieth power years. This introduces a theoretical
physics concept that sounds like pure science fiction, proton decay.
Speaker 2: This is a cornerstone of many grand, unified theories in physics.
These theories suggest that protons the fundamental building blocks of
atomic nuclei, the things that make up everything from a
rock to a human being to a dead star. They
are not perfectly stable. They don't last forever over unimaginably
long time scales.
Speaker 1: They decay so buryonic matter, the physical stuff of the universe,
literally dissolves. Every single atom that makes up the frozen
black bwarf of our sun. Any surviving rogue planets, any
distant asteroids, they simply disintegrate.
Speaker 2: They fade away.
Speaker 1: They evaporate, particle by particle into subatomic leptons and photons,
which then just disperse into the expanding void.
Speaker 2: All solid matter ceases to exist. The only structured objects
left in the entire universe at this point are black holes,
the absolute titans of gravity, holding immense amounts of mass
locked inside their event horizons.
Speaker 1: But even the black holes can't defeat thermodynamics, can they.
In nineteen seventy four, Stephen Hawking blew the world of
physics wide open by proving that black holes are not
completely black. They leak.
Speaker 2: Hawking radiation is a brilliant synthesis of quantum mechanics and
graph In the vacuum of space, quantum fields are constantly fluctuating,
bubbling with energy pairs of virtual particles, a particle and
an antiparticle are constantly popping into existence, colliding and annihilating
each other in a fraction of a second. But Hawking
realized that if this particle pair forms exactly on the
boundary of a black hole's event horizon, the intense gravity
can pull one particle in while the other escapes into space.
Speaker 1: Yet the escaping particle effectively steals a minuscule, almost unmeasurable
fraction of the black hole's mass.
Speaker 2: Yes, the black hole is slowly evaporating. It is an
agonizingly slow process. The largest supermassive black holes won't fully
evaporate until approximately ten to the hundredth power years.
Speaker 1: From now ten to the hundredth power a google of years.
It's a number so large that if you wrote a
zero on every single atom in the observable universe, you
would run out of atoms before you could write the
number out.
Speaker 2: It's beyond human comprehension.
Speaker 1: Though. When that final supermassive black hole evaporates in a
tiny flash of radiation, that is it the universe reaches
its absolute final state maximum entropeak heat death. I try
to visualize this with an analogy. Imagine a cup of
hot coffee sitting on a desk in a perfectly sealed,
perfectly insulated room. Okay, I'm picturing it. At first, you
have a system with highly concentrated energy. The coffee is hot,
the air in the room is cool. There is an
energy gradient. You could theoretically use that temperature difference to
do work like running a tiny stir.
Speaker 2: Engine, right because heat wants to flow.
Speaker 1: But over time, the heat from the coffee inevitably radiates
into the cooler air. The coffee cools down, the air
warms up just a tiny bit. Eventually the coffee in
the room reached the exact same lukewarm temperature thermodynamic equilibrium,
everything is the same temperature. Once that happens, nothing else
can ever happen. The coffee will never spontaneously heat back up.
The energy is evenly distributed, and the system is dead.
Scale that room up to infinity, and that is the
heat death of the universe.
Speaker 2: It is a profound chilling concept, a completely featureless void
of near zero energy. The photons and electrons left over
from evaporated black holes and decayed protons are spread so
infinitely far apart by the expansion of the universe that
they will never ever interact.
Speaker 1: Again, they'll never even builp into each other.
Speaker 2: There is no structure, there is no energy gradient, There
is no possibility for work, for heat, or for life.
Speaker 1: The very concept of a system is fundamentally dead. Every
atom that ever formed a star, a planet, or a
human brain is dispersed into a uniformity so complete that
no single region of the infinite void differs from any
other region.
Speaker 2: And that leads to a really wild philosophical realization about
the nature of time itself. In physics, we measure the
passage of time by the progression of entropy, by observing
change that's happening. A glass shatters, a star burns, a
clocktis right.
Speaker 1: Time requires a sequence of events, a before and an after.
But if the universe reaches maximum entropy, if absolutely nothing
can change, if no energy gradient exists to allow even
a single quantum event to occur. Ever, again, does time
itself stop having any meaning? Can time functionally exist without change?
Speaker 2: Mathematically, the dimension of time might still exist, But practically
and physically, the arrow of time completely vanishes without change,
without any measurable difference between the state of the universe
right now and the state of the universe a trillion
years from now time ceases to have any functional reality.
Speaker 1: It's just frozen.
Speaker 2: The universe simply is endlessly, unchangingly static. It is a
permanent silent equilibrium.
Speaker 1: Okay, let's take a deep breath.
Speaker 2: Yeah, that was a heavy journey.
Speaker 1: We have just traveled from right here, right now, all
the way to the literal end of time. Let's concisely
recap the mechanics of this journey we just took. We
started with the Sun's core collapsing, triggering the violent shell
burning and the helium flash ballooning the Sun into a
red giant that boils Earth's oceans dry.
Speaker 2: Then the gravity game started.
Speaker 1: We explored how Jupiter's gravity slowly pumps Mercury's orbit through
secular resonance, eventually turning the inner planets into chaotic, colliding
billiard balls. We watch the dying Sun pulse and violently
shed half its mass, creating a beautiful but deadly planetary nebula,
while the weakened gravity lets the outer planets and the
Orc Cloud simply drift away into the void.
Speaker 2: And then the galaxy stepped in.
Speaker 1: We face the terrifying galactic mechanics of the Andromeda collision
and the immense tidal forces of Sagittarius TAZ stretching dead
stars into atoms. And finally we track the absolute physical
dissolution of baryonic matter, the evaporation of black holes via
Hawking radiation, arriving at the completely featureless, unchanging void of
maximum entropy.
Speaker 2: It is a massive, crushing timeline. But bringing this massive
scale back to you the listener right now, understanding the
violent mechanics and the fleeting nature of the Solar system,
it shouldn't be a source of existential despair.
Speaker 1: No, not at all.
Speaker 2: We are examining the extreme far ends of physics here,
but the ultimate takeaway is per effective. It proves mathematically
that this exact era we are living in, this incredibly
narrow window of the universe's life span, where stars provide warmth,
where complex chemistry can fold into DNA, and where conscious
brains can actually look up and comprehend the physics of
the cosmos. It is an unimaginably rare, precious moment.
Speaker 1: The era of light and life is basically a microsecond
flash in the span of an eternally dark universe, and
that leaves me with one final lingering thought. The laws
of thermodynamics guarantee that eventually we reach maximum entropy and
nothing will ever happen again. It's a guarantee, But doesn't
that make the fact that anything happen at all, The
fact that gravity compressed a cloud of dust into a star,
that planets formed, that life sparked, and that you are
here right now listening to this a beautiful, mathematically profound miracle.
Speaker 2: It is the ultimate triumph over chaos. We are the
universe temporarily organizing itself, experiencing itself in a vibrant flash
of order against a backdrop of eternal equilibrium.
Speaker 1: So we want to know where you stand on this.
Does knowing the ultimate irreversible physical fate of the universe
make you feel incredibly insignificant in the grand chaotic machinery
of gravity, or does it make this precise moment of
your consciousness, this rare window of light, feel infinitely more valuable.
What do you think about this timeline and the physics
driving it? Leave a comment below and let us know
your perspective.
Speaker 2: The beauty of astrophysics is how it frames our own existence,
and we always love reading how you process these massive concepts.
Speaker 1: Thank you so much for joining us on this ultimate
cosmic journey. This has been thrilling threads. Keep looking up,
keep asking questions, and we'll see you next time.