All language subtitles for How.the.Universe.Works.S02E04.480p.HDTV.x264-mSD.HI

Narrator:
Our Universe is violent, deadly.

Cosmic bombs are everywhere.

Dr. Krauss: And the most crazy,
intense, violent explosions

you can imagine
are happening out there.

Narrator: The Sun spits flares
millions of miles high.

Magnetic monsters
rip worlds apart.

Galactic flamethrowers

fire gamma rays
halfway across the Universe.

It's like a cosmic blowtorch.

The energy of these things
is unimaginable.

Narrator: Mega-flares
light up the Universe.

They illuminate hidden secrets.

They're also a threat.

If you're in the line of sight,
watch out.

Narrator:
Our planet is under attack

from colossal, cosmic
firestorms.

Do these deadly mega-flares
threaten life on Earth?

♪ How the Universe Works 2x04 ♪
Megaflares
Original Air Date on August 1, 2012

== sync, corrected by elderman ==

An ordinary star field,

but home to one of
the most extraordinary stars

in our galaxy.

8.7 light-years from Earth,
this is UV Ceti.

This mysterious object

can grow five times brighter
in less than a minute.

Any planet circling this star
would be blasted by the heat,

quickly melting
its frozen surface.

Then, just seconds later,
the sun dims.

The planet retreats
into icy darkness.

But UV Ceti is about to go
way further.

The star begins to brighten,
but this time, it doesn't stop.

A runaway inferno,
in just 20 seconds,

it gets 75 times brighter
than normal.

UV Ceti has unleashed
a mega-flare...

...an immense explosion
of energy on the star's surface.

If our Sun fired off
a mega-flare like this...

...we'd be toast.

If you were standing
on the surface of the Earth

and the Sun were to get
75 times brighter,

even for only a minute or two,

it would really probably be
the last thing you'd ever see.

The temperature on the Earth
would rise up.

We'd have huge fires. It would
just basically cook everything.

Narrator: Earth is a long way
from UV Ceti.

We're safe
from that particular star.

But the more stars we study...

...the more flares we find.

They fire in all directions...

...sometimes, directly at us.

The closer a star is to Earth,
the greater the danger.

And one star is way closer
than all the others.

Our Sun looks stable and calm.

But behind the glare...

...the Sun is a monster.

Solar observatories
capture the violence.

Flares erupt
across its surface...

...gigantic explosions
on an unimaginable scale.

Dr. Batalha: One flare,
one of the most energetic flares

on the surface of the Sun
would be equivalent

to over 200 million
hydrogen atomic bombs.

It's enough energy

to power the entire human race's
energy consumption

for something like
2 million years.

Narrator:
Each flare is as bright

as 400 billion trillion
light bulbs.

But the visible light

is just a fraction
of the energy it emits.

Radio waves...

Infrared heat...

Ultraviolet light...

even X-rays...

...unleashed in every flare
at incredible intensities.

These are the biggest explosions
in the solar system...

...yet the force behind them
is simple...

...magnetism.

The Sun has an immense
magnetic field.

The energy stored in this field
powers solar flares.

Vast loops of magnetic force
push toward the surface.

Huge magnetic arches
rise out into space.

When two field lines cross,

it triggers a magnetic
short circuit.

This is a solar flare.

All the energy
trapped in the magnetic field

blasts out
at 100 million degrees.

It can hurl hot gas

a billion miles
out into space...

...an eruption 10 million times
more powerful than a volcano.

Magnetism -- the same force
that powers a simple compass

fuels the biggest explosions
in the solar system.

Yet by cosmic standards,
our Sun is puny.

As we look out into space,
we see even more active stars,

even more intense magnetism,

and then things
really start to get wild.

Dr. Krauss:
There are stars and objects

in our galaxy
and in other galaxies

that produce flares
of great intensity --

so great, they would literally
destroy all life on Earth

if they were nearby.

Narrator:
Outside our solar system,

titanic explosions
rock the cosmos

on a scale
we can barely imagine.

Far beyond the sun, we enter
the realm of mega-flares.

Narrator:
Our Sun is violent.

Flares explode with the force
of billions of atomic bombs.

But travel out into the cosmos,

and the explosions get bigger.

Other stars have flares so huge,
they're planet killers.

EV Lacertae
is 16.5 light-years from Earth.

Every day,
flares erupt on its surface.

But one mega-flare
smashed every record.

The star blasted out
10,000 times more X-rays

than the sun's
most powerful flare.

The ultraviolet light
was so intense,

the star turned blue.

This stellar firestorm
100 trillion miles away

was visible from Earth
with the naked eye.

[ Rumbling ]

If our sun flared like this,
we'd be incinerated.

But EV Lacertae is
a very different kind of star.

Compared to our sun, it is tiny.

This is a red dwarf.

Red dwarfs are stars that have
much less mass than the Sun.

They could be a tenth to about
four-tenths the mass of the Sun.

They're smaller. They're cooler.
These are dinky stars.

Dr. Krauss: They burn so slowly
that, unlike our Sun,

which will last
10 billion years,

some of them
will last 10 trillion years.

Narrator:
They're also relatively cold.

Their surface is just
5,000 degrees Fahrenheit --

half the temperature
of our Sun --

and 10,000 times dimmer.

Yet somehow, they're capable
of staggering violence.

That's because red dwarfs
are immensely magnetic.

The fields which form
inside them are enormous,

much more powerful
than our suns.

Dr. Krauss: That means
the magnetic-field energy

that can be released
when those fields get twisted up

is incredibly intense.

And even though these objects
are very dim in visible light,

they can produce flares

that are thousands of times
more energetic

than those released by the Sun.

You wouldn't want to be near
one of those when it went off.

Narrator:
All red dwarfs flare violently,

but EV Lacertae's flares
are off the chart.

That's because it's young --
just 300 million years old...

...15 times younger
than our Sun.

Dr. Plait: In one way, stars
are a little bit like people.

They're hotheads
when they're younger.

When stars are first born,
they're spinning very rapidly,

and that actually helps generate
magnetic fields, as well.

Narrator: The result --

a star 100 times more magnetic
than the Sun.

When its giant loops cross,
the mega-flare is colossal...

...a torrent of radiation
lasting 8 hours.

Big flares on our Sun

have the energy
of billions of atomic bombs.

EV Lacertae's monster flare
was 10,000 times more powerful.

Incredibly,
even these massive flares

are just a flicker
on the cosmic scale.

There are eruptions
millions of times brighter...

...explosions that can light up
a whole galaxy...

From a tiny star
with unimaginable power.

Narrator: This is the Australia
telescope compact array --

a network of five radio dishes

constantly listening
to the cosmos.

In 2004, they were struck
by a massive blast of energy...

...evidence of a mega-flare.

But this was bigger than any
we had witnessed before...

...the largest burst of power
ever recorded from our galaxy.

The object behind it
is truly bizarre --

a kind of star
we didn't even know existed

until a mega-flare gave it away.

I've studied black holes.
I've studied stars that explode.

I've talked about rogue planets
wandering the galaxy.

For my money, the scariest
single object in the galaxy

is a magnetar.

Narrator: Magnetars
are the most magnetic objects

in the Universe.

And this one beats them all.

Its magnetic field

is 1,000 trillion times stronger
than our sun's.

If it came near
our solar system,

the effects
would be devastating.

The first thing you would notice
is its magnetism

would wipe every credit card
in your pocket.

As you start to get closer,

anything metal on you
would be ripped away --

your earrings, your jewelry.

Once you got within a few
million miles of the magnetar,

its magnetism
would be so intense,

it would actually disrupt
the electrical signals

in your nerves, and your heart
would stop beating.

Get even closer, and the
magnetism would be so intense,

it would rip apart every atom
in your body.

Narrator: Amazingly,
this vast magnetic field

comes from an object
no bigger than an asteroid.

Our Sun is close
to a million miles across.

The magnetar, just 10.

But it's unimaginably dense.

It weighs more than the Sun.
This is incredible.

Take the Sun and squeeze it down

not just to the size
of the Earth,

but down to the size
of Manhattan.

Narrator: The entire mass
of a gigantic star

packed into a space
the size of a city.

Dr. Krauss: You could almost
walk around the star in a day,

except you couldn't,
because the gravitational field

is so intense,

the density of material
on these stars is so great,

that a teaspoonful of material

weighs several thousand
billion tons.

You would be crushed
beyond recognition in a moment.

Narrator: Dense and compacted,
the iron-rich crust

is under incredible
magnetic pressure.

Something has to give.

Fissures rip across the surface.

The crust splits open --

a starquake.

It's like an earthquake
on Earth,

except the crust literally moves
a half an inch.

It's just a little, tiny shift,

but that is a huge amount
of energy

because of this intense gravity.

It's like
a magnitude-30 earthquake.

Narrator: A flare erupts
from the fracture.

A trillion-ton cloud
of ultra-dense matter

blasts into space.

It lasts
just a tenth of a second.

But it unleashes more energy

than the Sun emits
over 250,000 years.

Dr. Krauss: The energy emitted
when one of these flares

from a magnetar is released --

in some cases,
more than a billion times

the energy emitted by the Sun.

Narrator:
Mega-flares are time machines.

They show us events
from long ago.

This magnetar is 50,000
light-years from Earth.

The flare we observed in 2004

actually happened
50,000 years ago.

It took that long for the light

to travel
halfway across the galaxy

and slam into our atmosphere.

If a similar mega-flare
exploded near Earth...

...we wouldn't
even see it coming.

Dr. Plait:
We would have no warning

if a magnetar were to have
another flare like this.

The event is so sudden
on the surface

and it creates so much energy,

it blasts out
at the speed of light,

and nothing can travel faster
than light.

So, basically, this just
happens, and that's it.

Narrator: Any life within
10 light-years of the blast

would be vaporized.

Thankfully,
even the closest magnetar

is too distant to threaten us.

We can't see them,

even with
the strongest telescope.

We've only detected these stars
in the flash of a mega-flare.

Yet these explosions are dwarfed

by an even more powerful
monster.

Second only to the Big Bang
in scale,

this is the ultimate mega-flare.

Narrator:
7.5 billion years ago,

many galaxies away...

...a supergiant star
is in trouble.

Its nuclear core
has run out of energy.

It's about to implode.

For a few seconds,
the colossal blast shines

a million times brighter
than our entire galaxy.

This is the most extreme
explosion in the Universe...

...a gamma-ray burster.

Gamma-ray bursters
are so powerful

that they can be seen
across the entire universe,

second only to creation itself.

Narrator: Two intense jets
of energy shoot out.

These two beams of gamma rays
are the ultimate mega-flare.

Dr. Plait: The energy of these
things is just unimaginable.

It's the entire power

that the Sun puts out over its
entire 10-billion-year lifetime,

focused into
just these two things

that last for maybe
a few seconds.

It's like a cosmic blowtorch
of gamma rays and matter

that march across the Universe.

Dr. Thaller: The most
high-energy, intense light

is gamma rays.

Gamma rays
are naturally produced

by things that are billions
of degrees hot.

There will never be
a hotter type of flare.

This is where it stops.
Gamma rays is it.

Narrator:
7.5 billion years

after the explosion
actually happened,

we see it in our skies...

March 2008.

A flare from halfway across
the entire Universe

shines even more brightly
than the closest star.

Something blew up
7 billion light-years away

that you could see with your
unaided eye on a dark night.

That should tell you something.

Narrator: It is the biggest
flare ever witnessed.

But it is also a sign...

of the birth
of the most destructive entity

in the Universe.

A black hole has formed

in the core
of the collapsing star.

It consumes the star
from the inside out.

When the star finally explodes
in a catastrophic supernova,

all that remains
is a newborn black hole.

Usually when we look
in outer space,

we see old black holes --

black holes that have been
around for millions of years.

But to see a baby black hole
being born --

that is an incredible event,

and that's what we think
is a gamma-ray burster.

Narrator: Amazingly, these
gigantic explosions are common.

We see more than 350 a year.

Kaku:
We see them every day.

Our satellites
detect them every few hours

in all directions
outside the Milky Way galaxy.

Narrator:
Gamma-ray mega-flares reveal

one of the Universe's
most awesome secrets --

a new black hole is born
every single day.

Most of these explosions
happened a long time ago,

far away from Earth.

But if one went off
inside our galaxy...

...it could be catastrophic.

If you were to put
a gamma-ray burst

100 light-years
from the Earth...

...it would be like igniting
a one-megaton nuclear bomb

over every square mile
of the surface

of the Earth facing that event.

You would be blowing up millions
and millions of nuclear weapons

over the planet.

It would be the end of all life
on Earth as we know it forever.

Narrator: Gamma-ray bursts

are the most powerful
mega-flares in existence,

but not the most dangerous
for us.

The greatest threat to Earth
sits terrifyingly close,

right at the heart
of our own solar system.

Narrator: We were once
blissfully ignorant,

safe in our solar system.

Now we know Earth sits
in a cosmic firing range.

Monster mega-flares
are everywhere we look.

But the deadliest cosmic weapon
of all

is right on our doorstep...

...our Sun.

We're lulled into thinking
that the Sun is static,

it's benevolent,
and is our friend.

Wrong.

The Sun is dynamic.

In some sense, it's alive.

It creates magnetism on a scale

that we can only begin
to comprehend.

Narrator: And its most powerful
weapon is this --

a coronal mass ejection, or CME.

A colossal solar explosion
rips a chunk of the star away

and torpedoes it out into space.

Coronal mass ejections
are related to flares,

but they're even larger.

You can sort of think of it

as a solar flare
being like a tornado --

very powerful, very intense,
very short-lived.

And a coronal mass ejection
is like a hurricane --

much more energy, much bigger,
and can last for days and days.

Narrator: CMEs start
with a magnetic short circuit.

Magnetic arcs emerge
from the surface...

...glowing with
trapped solar matter.

The loops cross, triggering
a firestorm of energy.

The Sun erupts.

Solar matter explodes from
the surface out into space...

...a monstrous cloud

of super-hot gas
and electric particles.

Dr. Krauss: When one of these
huge prominences is shot out,

an energy equivalent
of about 10%

of the entire luminosity
of the Sun for a second

is released towards the Earth.

Over 10 billion tons of material
is shot out

at a speed
of over a million miles an hour.

Dr. Plait: The power
of a coronal mass ejection

is sort of mind-numbing.

It takes our probes years to get
from the Earth to the Sun.

A coronal mass ejection

can cross that distance
in a couple of days,

sometimes in only a couple of
hours or even faster than that.

So these are tremendously
powerful events.

Narrator:
Powerful, but also deadly.

Because sometimes,
the Sun shoots a CME

straight toward the Earth.

The crackling, charged cloud

plays havoc
with our electronics.

It melts power grids,
blows fuses,

and disrupts communications.

But that's nothing
compared to the damage

that a really big CME could do.

Kaku: They can wipe out
satellites, GPS, the Internet.

All sorts of havoc
can take place

when this huge Tsunami
hits the Earth.

Narrator:
The damage to satellites alone

would total $100 billion.

Kaku: Think of a blackout
that hits not just one city,

but hundreds of cities
around the planet Earth.

Property damage
would be about $2 trillion.

We're talking about perhaps

a collapse
of modern-day civilization.

We can be thrown back perhaps
50, 100 years into the past

into a world
without electricity.

Narrator:
Big solar storms are rare.

On average,
a massive CME strikes Earth

every 500 years.

But it's happened before...

And it will happen again.

In 2003,
we had one of the largest

coronal mass ejections
ever recorded,

but fortunately,
it missed the Earth.

One of these days,
it's gonna hit the Earth.

One of these days,
one of these rifle bullets

will be aimed
right at the Earth,

and at that point, watch out.

Narrator:
Our planet is under attack...

...not just from mega-flares
in deep space...

...but from our own star.

The Sun fires billions of tons

of hot gas
and electric particles

into space every day...

...deadly solar weapons...

...sometimes pointing
straight at us.

What I find amazing is the fact

that the Earth is in the middle
of a shooting gallery.

Narrator: But we have survived
this onslaught.

We are protected.

The earth has a magnetic field.

It's incredibly weak,
but enough to keep us safe.

Kaku:
Think of an ordinary magnet

that you use
on your refrigerator.

That has more magnetism
than the Earth's magnetic field.

Narrator:
Without our magnetic shield,

every CME would strip away
Earth's atmosphere,

and we'd be fried
by solar radiation.

How do we know?

Because it happened
to one of our neighbors.

Kaku: Look at Mars.

Mars is an example
of what happens

to a planet
without a magnetic field.

Mars is a frozen desert

with an atmosphere

only 1% the atmospheric density
of the Earth.

It's because
it lacks a magnetic field.

Dr. Krauss: Over billions
of years, these particles

have actually stripped away
Mars' air,

and that's why it has
a very thin atmosphere now.

Here on Earth, we have a
magnetic field, and we have air.

This is not a coincidence.

So we can breathe
because of our magnetic field.

Narrator:
From Earth's surface,

safe beneath
our magnetic umbrella,

we see the power
of our violent Sun

in the northern
and southern lights.

Trillions upon trillions
of electric particles

strike the earth every second.

The magnetic shield funnels them
to the poles.

They energize gas molecules
in our atmosphere,

making them glow --

a chemical light show.

Oxygen shines green.

Nitrogen, blue or red.

The aurorae are evidence of a
battle between magnetic fields.

The Sun's field creates CMEs.

Earth's field shields us
from them.

Magnetism is nature's
most mysterious force.

Only now are we beginning
to understand

how it shapes the cosmos.

Mega-flares
make magnetism visible.

They shine a light

on the incredible power
of magnetic fields...

...fields that play
a fundamental role

in the Universe.

They impose order on chaos.

They weave their way

through the spiral shapes
of galaxies...

...fields hundreds of thousands
of light-years across,

yet 100,000 times weaker
than Earth's.

Smaller magnetic fields exist
inside galaxies.

They organize matter
into clouds of molecules --

spectacular nebulae.

These stellar nurseries
are where new stars are born.

Now we've discovered
magnetic fields

even permeate empty space...

...fields created
in the Big Bang

with just one quadrillionth
the strength of Earth's.

This is a magnetic universe.

Dr. Krauss:
What's amazing is this thing

that's invisible --
magnetic fields --

play such an important role
in every aspect of the Universe,

protecting us from the radiation
from the Sun

to explosions and red dwarfs,
to magnetars,

and to the most energetic,
violent processes

in the entire Universe --
gamma-ray bursts.

Magnetism plays a role
on every scale of the Universe,

changing the dynamics of objects

and making the universe
a violent and interesting place.

Narrator:
Mega-flares light up the cosmos.

They show us things
we can't otherwise see

from the other side
of the Universe...

...or from billions of years
in the past.

A black hole is born.

A star dies.

Distant events
and hidden mysteries.

In a flash,
flares reveal them...

...illuminating the awesome
secrets of the Universe.

== sync, corrected by elderman ==