All language subtitles for HTUW S05x05 Stars That Kill

SUB BY : DENI AUROR@
https://aurorarental.blogspot.com/

When the sun goes down,

the monsters come out to play.

Some of those stars you see are actual psychos,

and they'll kill you.

In the last decade,

astronomers have uncovered a sinister side to our universe,

killer stars

with the power to destroy on a cosmic scale.

We hear about death stars in movies,

but they actually exist in real life.

Solar systems torn to shreds,

living worlds vaporized in an instant.

Somewhere in the universe, dozens of worlds

just like ours are being annihilated

by killer stars.

Scared of the dark?

You should be.

Captions paid for by discovery communications

June 2015.

A small robotic telescope scans the night sky

over Chile, south America.

The all sky automated survey for supernovas,

or asas-sn for short,

is programmed to spot the bright flashes of light

that Mark the death of giant stars.

That night, the telescope found a faint glow in the sky

that nobody had seen before.

At first, astronomers think it's a nearby supernova.

But when they analyze the light,

they discover something extraordinary.

The exploding star was unimaginably far away,

nearly four billion light years.

To be visible from that mind-bending distance,

the flash of light had to be a record-breaker,

the brightest supernova in recorded history.

It radiated more energy than the sun

will radiate in its entire 10 billion-year lifetime.

But it did that in a month.

This is at the absolute edge.

This is the brightest we think a supernova can possibly be.

Astronomers name the record-breaking

blast of light asassn-15lh, an appropriate name,

because this superluminous supernova

was a mass-murderer.

This supernova isn't just going to destroy life

on the planets that orbit that star.

It's going to destroy life on millions of planets.

That's millions of apocalypse events.

The destructive power of 15lh

had little to do with explosive force.

This deadly assassin's weapon was light.

To understand how brightness

can cause devastation on a galactic scale,

planetary scientist Nina lanza

is supersizing a familiar backyard experiment.

All the light entering this giant lens

has been concentrated to a point right there,

which is maybe, you know,

half an inch to an inch in diameter.

And look, we're already ...

we're already catching wood on fire,

so that's amazing. That was only a few seconds.

Light is made up of tiny packets

of energy called photons,

and the more concentrated these photons are,

the greater their destructive effect.

So right here, we have more photons.

You can call this brighter.

It's much brighter in that little spot

than it is outside of the lens.

So brightness is catching this wood on fire.

Nina's backyard death ray

is thousands of times brighter than the sun,

but the superluminous supernova 15lh?

That shone hundreds of billions times brighter,

an onslaught of photons so concentrated,

it would have vaporized the surfaces

of nearby planets

and stripped away the atmospheres

of more distant worlds,

a real-life mass-murdering planet-killer.

And who knows?

Maybe some of the millions of worlds destroyed by 15lh

could have had civilizations just like ours.

For a normal supernova,

the kill radius is about 30 light years.

We think the intense uv radiation

from a supernova will destroy the ozone on earth

if the supernova happens within 30 light years.

A superluminous supernova like 2015lh

is so much more luminous than a normal supernova

that the kill radius is much larger.

Maybe 500 light years

or even out to about 1,000 light years.

Imagine a volume of space

stretching 1,000 light years in all directions.

It holds hundreds of millions of stars

and perhaps billions of living worlds.

Just one superluminous supernova in the center of this space

is all it would take to wipe this vast region

completely clean of life.

It's violent enough when a single star blows up

and destroys its solar system,

but these actually might be the true mass-murderers

of the universe.

So how do you turn a giant star

into a mass-killer like 15lh?

Astronomers have observed

only a few dozen superluminous supernovas,

but they think the secret to their formation is spin.

Superluminous supernovas start life

as oversized bright-burning stars

known as blue supergiants.

These blue supergiants live fast and die young,

burning through their fuel supply

in just 10 million years.

As they die, their cores collapse to form

a super-dense object called a neutron star,

and if this neutron star is spinning fast enough,

it can develop intense magnetic fields,

transforming into something new

and altogether more extreme ... a magnetar.

All neutron stars have very, very intense magnetic fields,

but sometimes a true monster is created.

There really is a limit to how powerful a magnetic field can be

before it starts to rip apart space and time itself,

and right on the edge of that is a magnetar.

Magnetars are like neutron stars on steroids.

Their intense magnetic fields reach out

into the expanding outer gas layers of the dying star,

raising temperatures

and releasing an intense burst of light.

But to get the kind of brightness produced by 15lh,

you need a very special type of magnetar,

the most powerful, fastest-spinning magnetar

we have ever seen.

It pushes the magnetar model to the absolute limits,

because you need the magnetar to be rotating with about

a 1-millisecond spin period.

That means the neutron star has to be spinning

1,000 times per second,

and then over the course of the month

of this explosion, you need to ...

you need to take all of that rotational energy

that's inside the neutron star and blast it outwards

into the surrounding star to make the light show

that we see billions of light years away.

15lh was the brightest supernova

scientists have ever seen,

and almost like a perfect storm.

It could be the brightest supernova we'll ever see.

There's a theoretical upper limit

to how much energy a supernova can generate,

and this thing was right at the edge of it.

Fortunately, superluminous supernovas

are also super rare,

so we're unlikely to have one explode

in our neighborhood any time soon.

But the galaxy is a big place,

and there are plenty more killers out there.

And as powerful as light can be,

the power of dark can be just as deadly.

Supernovae may have many ways to kill you.

A superluminous supernova might kill you in a death by fire.

But an unnova,

death by ice.

Some of the brightest lights in the universe

are created by young blue stars

as they die in bright explosions.

Superluminous supernovas are the ultimate example,

but other types of stars can go supernova, too.

Yellow stars like the sun swell up as they age,

transforming into oversized monsters known as red giants.

The biggest of these bloated stars

are called red supergiants, and astronomers often see them

explode in bright, violent supernovas.

The bigger the red giant, the bigger the bang.

But there's a problem.

Nobody has ever witnessed the flash of

the very biggest red supergiants in our galaxy.

These most massive of bloated old stars

have to be dying.

But if not in a flash of light, then how?

Now scientists have come up with an extraordinary theory.

Instead of exploding in a bright supernova,

the biggest of the red supergiants

are simply blinking out of existence.

Scientists dub these weird disappearing deaths "unnovas,"

and new evidence suggests these unnovas

could be cold-blooded planet-killers.

You're looking up into the sky,

the sun is shining,

and all of a sudden, it just turns out.

That's what an unnova would look like.

Kipping: It would be the biggest catastrophe

in the history of the planet.

Life as we know it would not be able to survive.

Scientists believe the key to the biggest

red supergiants disappearing is a super-efficient

transformation from a giant, burning ball of gas

to a tiny, dense black hole.

Everything has to be perfectly tuned to get an unnova.

The star can't be rotating very quickly

and the outer layers can't expand much.

When all the conditions are right,

it just collapses into a black hole.

They basically just, whoomp, become a black hole.

It's not unusual for red supergiant stars

to form black holes when they die,

but most do it after they've released

the violent flash of light we see as a supernova.

But the biggest supergiants have so much mass

and so much gravity in their cores

that when they collapse,

not a single photon of light escapes

from the newly formed black hole.

To an observer, the star simply disappears.

The death of a star without the flash.

An unnova.

Bullock: It's almost like the star has fallen in

and has forgotten to come out.

But more realistically, what's going on

is when it falls in, it just can't come out.

It's created so much gravity around itself

that even an explosion doesn't allow it to escape.

It doesn't get to explode.

It just falls right into a black hole.

So what makes unnovas planet-killers?

The biggest red supergiants age relatively quickly,

dying after just 10 million years.

But astronomer David kipping believes that just might be

enough time for these giant stars

to create potentially habitable worlds.

Planets can form pretty quickly. They can form in ...

within a million years around these stars.

So there should be time

for these massive stars to form planets.

And in fact, when we look at the remnants of massive stars,

we indeed find rocky planets around them,

so as far as we can tell,

these stars really should have worlds orbiting them.

Imagine a lone, rocky world

warmed by the far-distant light of a red supergiant star.

Simple life clings to shallow rock pools

on the young planet's surface, but their warm,

comfortable existence is doomed.

High in the sky, the far-distant supergiant sun

is burning through the last of its hydrogen fuel.

The force of gravity pushing in

overcomes the force of fusion pushing out,

and 20,000 trillion trillion tons of hot,

burning hydrogen gas collapses down

into a single point in space.

A black hole.

Surprisingly, the black hole that makes the unnova so dark

doesn't put the planet in immediate danger.

This is one of the biggest misconceptions of movies,

is that suddenly, when the star becomes

a black hole, then the planet is going to be sucked into it.

The gravity of the black hole

is exactly the same as the gravity of the star,

as long as it hasn't lost any mass.

From a distance, if you're orbiting this star,

it's the same as orbiting the black hole.

Nothing would change.

As the supergiant star collapses,

the view from the far-distant planet

would be surreal.

What you're going to see is, there's your star in the sky,

and then a minute later, it's gone.

You will actually see it collapse,

forming a black hole, and the whole thing

just falls into it and that's that.

What would happen next would be a long, slow, cold death.

You're basically turning off your star.

A fleeting moment, but the beginning of a winter

that would never end.

If you suddenly turned off the light from the sun,

life wouldn't actually be immediately extinguished.

It would just be like the night.

We would be a little bit cooler than normal.

But eventually, over time, over weeks, over months,

over years, the planet would begin to freeze over.

After 100 years, a global ice age

engulfs the planet.

First the land, then the oceans.

The oceans would freeze over into a thick crust.

Maybe a little bit of liquid water

would still be there at the bottom of the ocean,

warmed by volcanic vents.

Eventually what you're left with are things

that don't depend on sunlight to live.

Maybe there are tube worms living in vents, cracks,

hydrothermal vents in the bottoms

of the oceans and that sort of thing.

But even those can't possibly live forever.

The internal heat of the planet

continues to radiate out into space.

The surface temperature drops below

minus 350 degrees fahrenheit,

and the atmosphere collapses onto the surface as snow.

The core of the planet

can no longer support active geology.

All life is gone.

The planet is dead.

So these habitable worlds will eventually end up

being just these spheres of ice.

Whether killed by the light of a supernova

or by the darkness of an unnova,

planets are in the firing line from killer stars.

But research recently released suggests that stars, too,

can fall victim to murder, and some of these killings

are straight out of a horror movie.

How can an old star that's on the way to die

get more mass so it can become young again?

Well, it can do exactly what a vampire does.

It can suck life from something else.

2012.

The hubble space telescope makes a gruesome discovery.

It finds killer stars

sucking the life from their neighbors.

These vampire killers are found lurking inside

tightly packed groups of stars known as clusters.

Stars are born in giant clouds of dust and gas,

and these clouds have enough material

to make dozens or even hundreds of stars.

We call these family of stars star clusters,

and we think they're all roughly the same age.

Young clusters shine like jewels,

with an array of bright colors ...

blues, yellows, and reds.

But this starry rainbow changes over time.

The blue stars disappear first.

These are the biggest stars in the cluster,

burning brightly and dying young after millions of years.

Next to go are the yellow stars.

These medium-sized stars age over billions of years,

gradually turning red like ripening fruit.

After 10 billion years,

the entire cluster matures to a deep red.

This gradual shift in color is useful to astronomers

because it allows them to judge just how old a cluster is.

When you look at a population of stars in one place,

if you see a lot of blue stars, you can be pretty confident

that that must have young stars.

They couldn't have been born too long ago

because blue stars are massive

and massive stars go through their fuel quickly

and live very short lives.

But in the 1950s, astronomers spotted

something seriously weird in an ancient cluster.

Tucked amongst the old red stars,

they found a handful of brightly shining young blue stars.

New stars don't usually form inside mature clusters,

so how did they get there?

The only explanation?

Somehow, the old stars were getting younger.

Astronomers dub these age-defying stars

blue stragglers.

In some clusters, we see these blue stars

that appear younger than they should.

In some ways, they're kind of straggling behind

the natural aging of the cluster.

Something must be actively rejuvenating a star,

but what could do that?

If you imagine these blue straggler stars

were people in a crowd,

these stars would look like they had been given a facelift.

They're masquerading as younger stars when really

they're just as old as everybody else in the room.

Astrophysicist Natalie gosnell

believed the blue stars were being rejuvenated

by a fresh supply of hydrogen fuel,

but where was it coming from?

In 2015, Natalie took a closer look

at the hubble images of the blue straggler cluster.

She discovered that most of the young-looking stars

were in binary partnerships with the corpses of dead stars

that appeared to have had their gas sucked away from them.

Gosnell: So in movies,

vampires are perpetually youthful

because they are sucking blood from humans,

and so in this case, we have stars that are

sucking gas and material from other stars,

keeping them looking young.

Gas is the fuel that allows all stars to burn,

and with new gas, a star is revitalized.

But for a star to turn into a gas-sucking vampire,

scientists believe it needs to start its life

in a close-orbiting binary pair.

If you have two stars in orbit about each other,

which is a very common thing in the universe,

then they're not going to be the same mass in most cases.

The one that's more massive will evolve more quickly,

and as it ages and evolves, it will swell up,

and it will get so large that its outer surface

can come in contact with

the gravitational region of influence

of its partner star.

The smaller star becomes a vampire.

It sucks the bloated outer layer of gas

from its bigger partner.

And as the vampire feasts, it burns hotter and hotter,

turning a brilliant, youthful blue.

The vampire's victim is sucked dry,

reduced to a lifeless stellar core

known by astronomers as a white dwarf.

But, like any good horror movie,

this murderous tale has a twist ...

exploding zombies.

There's all sorts of stories about zombies.

What if the dead could actually come back

and take revenge on the people who killed them?

Well, something similar really does happen with stars.

As the blue straggler ages, it swells so much,

the dead white dwarf starts to steal

some of its gas back from the vampire.

The dead star rises again to become an exploding zombie.

As that material piles up, it gets hotter and hotter,

and you're basically piling up tremendous amounts of hydrogen.

And if it gets hot enough and the pressure gets enough,

basically you have created a hydrogen bomb

the size of a planet.

That star explodes.

These stars can get revenge.

Once the zombie explodes,

it takes out the vampire that sucked its life away.

For decades, astronomers have been puzzled

by the number of tiny, dead white dwarf stars

they see exploding in the night sky.

But here finally could be an explanation ...

our galaxy is filled with vampires

and exploding zombies.

What does that say about the rest of our galaxy?

A huge chunk of the stars in our galaxy

are sort of stealing life

from their friends to stay forever young.

The birth and death of vampires

could be the reason we see blue stragglers today.

But amazingly, it could also explain

why we're here, too.

There's no way in this universe

to get life without death.

You can't possibly have materials

to build planets or people

or anything around us without supernovae.

So these vampires and these zombies,

well, actually, they're our parents.

You and I, we could be the result

of these vampire stars transferring gas back and forth

in these binary systems, leading to stellar explosions

that blew out the building blocks of life

into the universe.

Our home star, the sun, is not in a binary pair.

But if you think that makes us safe

from cosmic vampires, think again.

New observations suggest some vampires can fly.

And a close pass by our solar system

is all it takes to finish off the earth

for good.

The universe seems to run like clockwork.

Moons orbit planets.

Planets orbit stars.

And the stars themselves revolve around

the center of our galaxy.

Everything seems to be in the right place,

ordered and stable.

But some killer stars don't follow the rules.

Every once in a while, you find something

careening across the sky in exactly the wrong direction.

How did that rogue star get there?

In the last decade, scientists have spotted

hundreds of lone stars

hurtling through our galaxy like ballistic missiles.

Scientists named these rogues runaway stars

because they can travel at incredible speeds.

We're talking about stars that are going

a thousand times faster than a rocket.

Hypervelocity anything is dangerous.

A hypervelocity star is incredibly dangerous.

A ball of hot gas a million miles across

careening through our cosmic backyard.

Runaway stars don't even need to score a direct hit

to inflict damage.

Even grazing the outer limits of our solar system

could be enough to destroy the earth.

You don't want any star getting too close to us

under any circumstances, because that could disrupt

the orbits of the planets.

A star passing by wouldn't even have to get

all that close to us to wreak a huge amount of havoc.

We have the giant oort cloud of comets that extends as much

as two light years away from the sun.

If a star passes anywhere close to there,

we could be rained on by destructive comets.

All of the planets in that solar system

would either be disrupted

or fired into the ... into the star,

and I would expect no solar system

to remain afterwards.

Astronomers traced the paths of these runaway stars

and found that many came from the galactic center.

In the middle of our galaxy,

we see stars that are trapped in orbit

around the central black hole.

They're actually kind of buzzing around

like a hive of angry bees.

Well, these stars interact gravitationally with each other,

and sometimes they can fling each other

clear across the galaxy.

Most runaway stars are harmless to us.

They shoot straight out into space

from the galactic center.

But from time to time,

we find runaway stars a little closer to home.

In 2016, astronomers turn their attention

to a rogue star just 3,000 light years away from the earth.

The star's trajectory and its composition

didn't seem to make any sense.

There's a star, sdss j1128, and it's weird.

It's weird because, first of all,

it is moving extremely rapidly through the galaxy,

way faster than it could possibly be moving

if it's just simply in orbit.

Something gave it a huge kick.

But it's got something else unusual about it as well.

It's a star much like the sun,

but it seems to have a lot of carbon in it,

and that's unusual.

Sun-like stars only produce carbon

at the end of their life cycle,

once they've swollen up to form red giants.

But here was a star that was burning through its hydrogen

in the regular part of its lifetime

covered with carbon.

What happened there?

Scientists now believe the carbon-rich runaway star

must have once been a vampire locked in a very close,

very fast binary partnership

with a much larger supergiant star.

The vampire sucked carbon-rich gas

from its bloated giant partner,

but the red supergiant was a reluctant victim

and exploded in a vast supernova.

The force of the blast should have taken the vampire out,

but its orbital speed was so great,

this carbon-stained star was flung away into space.

These two stars are going around each other quite rapidly.

When one of them blows up, it loses most of its mass.

It loses a lot of its gravity.

It doesn't have enough gravity

to hold on to the lower-mass star.

So they're spinning around, this one blows up,

and suddenly, this one finds itself

slingshot out into the galaxy, and that explains everything.

It got the carbon from the high-mass star.

The high-mass star blew up and flung that lower-mass star out

at very high velocity.

So what are the chances of our planet

getting fried by a flying vampire star?

In the vastness of the galaxy,

our solar system presents a mercifully tiny target.

It is so rare for any two stars

to get close enough together for this to happen,

even over the billions of years that a star can live,

that it's almost never going to happen

in the lifetime of any given star.

Flying vampires may be unlikely to destroy the earth,

but there's another type of killer star out there

that offers a clear and present danger,

and we know it could hit us because it's done it before.

March 2008.

Stargazers watched open-mouthed as a faint light in the sky

blinked into life and less than a minute later faded away.

A rare treat for the stargazers, but a stark reminder

that our planet is in the firing line

from the most powerful type of killer star in the universe,

a cosmic superweapon known as a gamma ray burst.

Bullock: Gamma ray bursts.

These cosmic ray guns are the most powerful,

the most deadly weapon

that the universe has come up with.

The jets of the gamma ray burst

actually don't last very long.

They go off in really just a couple of minutes.

But in that time, the energy released

is equivalent to a hundred trillion nuclear weapons

going off every second for a hundred billion years.

Gamma ray bursts are super-concentrated beams

of high-energy light, and they pack enough punch

to reduce nearby planets to vapor.

They're a kind of supernova,

but it's more like a super supernova,

the idea being that instead of blowing up a star

and letting the debris expand in every direction,

what if somehow,

instead of blowing up in every direction,

it blew up in one direction,

that it was somehow focusing all of that material

and it was being shot out like a beam

from the explosion center.

Bullock: The key insight here

is that we're not talking about something

that's exploding like a sphere

and spreading its energy out in all directions.

A gamma ray burst is beamed, so it's taking all of its energy

but pointing it right at us

and firing it directly towards us.

That's why it's so powerful.

The 2008 gamma ray burst landed a direct hit on the earth,

but it had come from so far away,

this superweapon appeared to have lost its punch.

Astronomers quickly calculated where the beam had come from,

and they pinpointed a location on the far side of the universe.

Incredibly, this cosmic sniper's bullet

had been traveling through space for seven billion years,

far longer than the age of our solar system.

We're talking about something that was so energetic that

had you been looking at it with your naked eye,

you could see it, even though it was more than

seven billion light years away.

Can you imagine something that energetic,

something that violent appearing as a gentle little star

going on and off in the sky?

Think about that for a second.

You've got this thing that's so bright

that you could see it by naked eye,

even though it's halfway across the observable universe.

In 2008, we got lucky.

If the same gamma ray burst had gone off

within a few thousand light years,

the earth's atmosphere would have been turned to plasma.

But we're safe now, right?

These things are happening somewhere in the universe

every day, okay? Every day.

I am not misspeaking here.

Not every year, not every century,

not every millennium.

Every day, somewhere in the universe,

in the hundreds of billions of galaxies

making up our cosmos, there is a supermassive star

that is creating these jets and frying everything

within a few hundred light years of itself.

So where do these planet-melting jets come from,

and how worried should we be?

Thompson: So what you do is you take a massive star

that's rapidly rotating.

A massive star that's rapidly rotating burns through

all of its nuclear fuel and eventually produces

an iron core at its center.

That iron core becomes unstable

and collapses to a neutron star.

If that neutron star is rapidly rotating ...

that means if it's spinning about 1,000 times a second ...

it will have a huge store of rotational energy.

This energy is concentrated as the star shrinks,

constrained by the neutron star's powerful magnetic fields.

Eventually, with nowhere else to go,

the pent-up energy bursts from the poles

of the neutron star.

Thompson: It can make a jet,

almost like squeezing a tube of toothpaste.

The jet can go punching through the star in each direction.

It essentially sets off a magnetized bomb

that then produces these jets

that just go ripping through the star in one direction

and out each pole, the north and the south pole.

And the amount of energy that is packed into these beams

make them death rays.

These are the single most energetic events

going on in the modern universe.

So what's the likelihood of a direct hit on earth?

The simple answer? We just don't know.

The problem with gamma ray bursts

is that they're so dangerous from so far away.

There actually may be stars out there

about to go gamma ray burst

that are pointed towards us we don't even know about.

We've made a survey of the sky,

we've identified which stars we think are dangerous,

and we don't appear to be looking right down

the gun barrel, so maybe for now, we're safe.

We don't have to stay up late at night worrying about

being killed by gamma ray bursts,

but the universe is big and old,

and that means weird things happen all the time.

Our solar system could well be taken out

by a gamma ray burst in the future.

But it's a big universe, we're a small target,

and that stacks the odds in our favor.

In the meantime, astronomers have caught

another killer in the act, and they think that

this sinister star type will almost certainly be

the same killer that finally destroys the earth.

We now know that our universe

is filled with killer stars

and that right now, some planet somewhere

is about to be toast.

But until very recently, the evidence we had

for this mass planetary slaughter was indirect.

We've seen that there are a lot of death stars out

there that are frying planets all the time.

Now, we've never seen any of these planets

actually get destroyed by these stars,

except once, and it turns out that was a planet

that may have once been much like earth

and it was orbiting a star that was once much like the sun.

2015.

Astronomer David kipping is poring over data from kepler,

a space telescope designed to spot alien planets

as they pass in front of their host stars.

A white dwarf star

with a very unusual signature catches his eye.

Instead of being dimmed by a neat, round planet,

the tiny star appeared to be surrounded

by vast chunks of disintegrating rock and dust.

What we're seeing from this white dwarf

are multiple dips in its brightness,

sometimes as much as 40 percent of the light being blocked,

and they're all on slightly different periods,

but all roughly about five hours,

which means we have something orbiting very close in,

but it's in clumps.

What could these clumps be?

They were too tightly packed for a swarm of asteroids

and too close to their host star to be icy comets.

The best explanation we had

was that this wasn't just one planet

going around this white dwarf star.

They were very small planetesimals

that were probably the product of a disintegrating planet.

The white dwarf star had been caught in the act

of murdering its own planet.

So a planet which is so close to that white dwarf star

that the tidal forces,

the gravity of that white dwarf, has ripped apart the planet,

and now we're seeing the fragments

fall into the surface of the white dwarf.

It was a beautiful discovery.

I mean, we had suspected this was happening,

but to actually see the direct evidence with ...

with almost your own eyes,

you know, seeing this light curve,

seeing a planet disintegrating right before you,

was confirmation of something

we had suspected for a long time.

We've only seen one star killing one planet,

but scientists suspect this same act of murder

could be happening all over the cosmos.

If white dwarfs can destroy planets,

then that means that 90 percent of stars

are actually capable of destroying planets,

so there's ultimately no safe haven for planets.

It's also a chilling look into the future.

In a few billion years' time, our sun will begin

its transformation into a white dwarf.

At first, it'll swell up,

engulfing the inner rocky planets,

Mercury and Venus.

Now, that means that the planets

will be orbiting around inside the sun.

Usually we orbit through empty space.

There's nothing really to change the way

we move around the star.

But inside the sun is a lot of gas.

We'll be dragging against that.

And that will take energy away from the planets

and they will spiral in, closer and closer to the star.

Our bloated star blows off its outer layers completely,

leaving behind a tiny, dense white dwarf

and revealing the scorched earth,

now on an ever-decreasing death spiral into the sun.

If you're getting closer and closer to the white dwarf,

you're doomed, because eventually,

your rocky planet will be ripped apart.

The intense gravity of our white dwarf sun

pulls on the charred remains of the inner planets,

and piece by piece, they break apart.

So if the planets do survive being in the sun's envelope

and they're now orbiting close to the surface

of this white dwarf star, first, Mercury is going to go.

It's going to be ripped apart.

Then Venus is going to be ripped apart.

And finally, the earth will cease to exist.

So maybe in a few billion years,

an alien civilization will be looking at the sun,

and the sun is no longer this big, luminous star.

It is now a dead white dwarf.

And they will notice a planet

about the same size of the earth going around it,

but that planet, just like the case with the kepler data,

will be disintegrating in front of their eyes

and they will wonder about whether in the past,

there had been a civilization or life

on this earth-sized planet.

The star that brings us light and warmth today

may one day rip our planet to shreds.

Our own sun will become a killer star.

But in time, the atoms that make up

our planet and everything around us

will be returned to the cosmos

as our dead star gradually fades away,

and perhaps new stars will be born from those pieces

and the cycle of life and death in the universe can begin again.

It's sad to think that a star might destroy planets,

because after all, stars are life-giving.

Our sun gives us life and we're here because of it.

But eventually, our sun is going to kill us, too.

Stars giveth and taketh away.

Killer stars may sound like something evil,

but there's no life without death.

You have to turn the cycle of the universe.

It really is the way the universe works.