All language subtitles for How the Universe Works s08e06 When NASA Met Jupiter.eng

NASA's revolutionary Juno probe

is on a daring voyage
to Jupiter.

Its goal... to reveal
the the deepest mysteries

of our solar system.

Everything we see
in the solar system today

is affected by Jupiter
somehow in the past or now,

all the asteroids,
all the planets,

the moons,
the comets, everything.

So in many ways, Juno is
actually giving us a view

into the history
of our planetary system,

even the history of Earth.

Juno's mission is risky.

Jupiter could eat
the spacecraft like that.

But by diving perilously close

to this monstrous world,

Juno could change everything
we know about our solar system.

If you want to know
what's happening,

you got to get up
close and personal.

captions paid for by
discovery communications

Independence day, 2016...

Juno arrives at Jupiter

and gets to work.

The probe angles its
high-resolution camera

towards this stormy world.

Juno's snaps do not disappoint.

The images returned from Juno
are just beautiful.

Suddenly you have this
magnificent mosaic

of this planet.

As a human being, I'm like,
"oh, my gosh, look at this.

This is amazing. This is
coming back from Jupiter."

These are the closest-ever views

of Jupiter,
a world 500 million miles away.

But we didn't send Juno
just to take pictures.

One of its main goals is to peer
deep into Jupiter's dark heart.

One of the big questions
we have about Jupiter is,

does it have a core?

And you'd think, well,
of course it has a core

like every planet has a core.

The Earth has a core.
Everything does.

Well, it turns out,
Jupiter might not.

Knowing what lies at
a planet's core

allows scientists to wind back
the clock billions of years

to the formation of the planets.

If Juno can reveal what lies
deep within Jupiter,

it could change
our understanding

of how the gas giant formed.

If Juno finds a solid core,
it could mean

Jupiter first formed
as a rocky planet like earth

then kept growing,

but if Juno finds no core,

it could mean that
Jupiter skipped the rocky stage

and formed straight
from a cloud of gas.

Answering this question
could shine a light

on other mysteries, too.

If we can figure out
how Jupiter formed,

we can figure out the rest of
the story of the solar system.

So how do you probe down
into the interior of a planet

when all you can really see
are the very tops of the clouds?

Well, incredibly,
you can use gravity.

As Juno orbits Jupiter,

it can sense in its orbit

tiny little variations

in the gravitational pull
of Jupiter.

As Juno speeds around Jupiter,

gravitational spikes
tug on the craft.

Turns out, some parts of Jupiter
are denser than others.

If Jupiter were some solid ball,
then as Juno passes by it,

as it passes very close
above its cloud tops,

the orbit, the trajectory
would be very smooth,

but in fact,
if Jupiter has layers,

or places where
there is more mass

and places where there's less,
then it's gonna pull on Juno

a little bit differently.

Passing over areas
of concentrated mass

gives Juno a speed boost.

So what they do is,
the engineers back on earth

can basically just say,

"how fast is it moving
right now?

How about now?
How about now?"

And you build up a map of
where the mass is in Jupiter

underneath the spacecraft
as it passes around.

Juno's instruments
begin to map out

the heart of gas giant,

revealing the mysterious core
for the first time.

What Juno found was
this amorphous mass,

a fuzzy thing
in the center of Jupiter.

It's not as solid as we expected

if it were just
a metal and rock core,

but there is something there.

In the center of the planet,

Juno detects hydrogen
and rocky material

dissolved and blended together.

It's a type of planetary core
we've never seen before.

Astronomers
describe it as fuzzy.

We thought we were gonna find
an avocado.

Instead, we found
a bowl of chili.

It's a hydrogen fluid
chili con carne.

So none of our models
of the interior of Jupiter

turned out to be correct.

That means we have to go back
to the drawing board.

One theory is that Jupiter

didn't form from rocks or gas

but from tiny pebbles
less than an inch wide strewn

across the early solar system
4.6 billion years ago.

These pebbles came together.

They accreted to form
a massive object

that was the sort of seed,
the core of Jupiter.

The swarm of pebbles

clumped together
to form one giant core

20 times the mass of Earth,

but these pebbles can't sustain
this growing planet for long.

Eventually,
we need to make a jump

from those centimeter-size
particles

up to really large things, like
100-kilometer planetesimals,

to really kick-start growth
of a planet.

As Jupiter grows,
its appetite becomes insatiable.

The cores of other
would-be planets are drawn in

by its immense pull
and absorb on impact,

causing Jupiter's core
to transform.

Huge chunks of incoming rock
are mixed up with gas

and the pebbles
that originally built the core.

We think that core material that
might've been there is actually

dissolved and mixed in
with the rest of the planet.

This mix of rock,
gas, and pebbles

leaves the core
in a strange state

somewhere
between solid and liquid

or, in other words, fuzzy.

Once Jupiter's core reaches
a critical mass,

its gravity pulls
in all nearby hydrogen gas,

building the Jovian atmosphere

and leaving the fuzzy core

trapped beneath thousands
of miles of thick clouds.

And that is what formed Jupiter
as we know and love it today.

Juno's discovery of
Jupiter's fuzzy core

could rewrite the book on

Jupiter's early years, but Juno
is just getting started.

We haven't even scratched
the surface

of the number
of mysteries there are.

There's more to
Jupiter than meets the eye

as Juno's instruments
begin to reveal a darker side

to this giant world.

Jupiter's environment
is one of the most vicious

in the solar system,
and that's because

of its incredibly
strong magnetic field.

And Juno is caught
right in the middle of it.

The gas giant Jupiter

holds clues to the mysteries
of our solar system,

and in 2011,

NASA launched a billion-dollar
mission to uncover them.

Three, two, one, ignition.

And liftoff of the Atlas V

with Juno on a trek to Jupiter.

To reach its target,

Juno embarks
on a five-year journey.

Sending any spacecraft
to another planet

is gonna be tough,
but sending one to Jupiter

is really
pushing things pretty hard.

Juno weaves through
the solar system

with extreme precision.

The craft battles violent
temperature changes

and navigates carefully
through the asteroid belt.

If there's a fleck of dust
in your path

and that thing slams
into your spacecraft,

it could do significant damage.

1.7 billion miles
into its mission,

Juno finally nears its target,

but the probe is hurtling
towards Jupiter

at 165,000 miles an hour.

Juno is moving really fast.

It's one of
the fastest spacecraft ever.

You need to go fast enough
to get there, but then you need

to be slow enough to be captured
by the gravity of the planet.

You need to get it just right.

Entering orbit around

Jupiter is the trickiest part
of the mission.

Get it wrong and Juno could slam
into the planet

or drift out into deep space.

To successfully get Juno
to enter a stable orbit around

Jupiter
as almost the same as, say,

shooting a basketball
from London

and having it on the land on
the front of the rim in New York

and just sitting there balanced.

I could do it, but can NASA
do it with Juno?

NASA has a neat game plan.

Juno performs a backflip
in space

and fires its thruster
towards Jupiter.

Everything is going smoothly.

We're continuing to burn
and change our velocity.

The rocket burns for
35 nail-biting minutes,

reducing the craft's speed
by 1,200 miles an hour.

Finally, the probe
achieves orbit around Jupiter.

Right on July 4th
during the fireworks

we just got into orbit.

In many ways,
we're firing a rocket motor.

I mean, it is fireworks.

Safe in orbit,

Juno turns
its instruments to the planet

for a crucial part
of the mission...

investigating Jupiter's
magnetic field.

Deep below the stormy surface,
liquid metallic hydrogen

flows endlessly
around the planet,

producing a huge magnetic field.

This magnetosphere
stretches over 600 million miles

beyond the planet,
reaching all the way to Saturn.

If your eyes could actually see
Jupiter's magnetosphere

and you tried to look at it
while standing on earth,

it would look about as big
in the sky as the moon.

And within this magnetic field,

Juno faces an invisible threat.

Jupiter has an enormous
magnetic field.

It is so enormous
in terms of space,

but also in terms of power.

High-energy particles
from the Sun

are funneled into
deadly radiation belts

guided by the giant
planet's magnetic field.

The magnetic field traps charged
particles coming from the Sun

and circulates them
around that system

and just bombards
anything in the vicinity,

including our fragile
little spacecraft.

Closer to the planet,

radiation levels are up to
30 times greater

than they were inside
the reactor core room

during the Chernobyl disaster.

This is radiation.

This is bad news.

These particles,
they would hit you.

They would rupture your DNA,
rupture your cell structures,

and you would die.

This blistering
radiation is bad news

for the spacecraft as well.

The charged particles threaten
to destroy electronic

and navigational systems,
but Juno has armored up.

It's not some delicate,
beautiful, gossamer thing

that you are sending
to orbit Jupiter.

It's more like a tank.

You have to protect this thing
or else

it's not going to last
very long at all.

We've got a couple hundred
pounds of titanium

on the spacecraft
just trying to shield us

from what Jupiter
might throw at us,

so it is in a sense we're like
an armored tank going into war.

Lightweight titanium is tough.

Juno's 1/2-inch-thick
shielding blocks 99%

of Jupiter's vicious radiation.

But even at this reduced rate,

Juno can't survive
the bombardment for long,

so the craft sets itself
on a unique orbit

around the gas giant.

It actually has a very
long orbit

where it spends
most of its time far away,

and then every once
in a while dives in and goes,

"oh, hot, hot, hot, hot.
I zoomed in too much,"

and then goes safely away
to communicate and process

and then back in again.

Juno takes a mighty gamble

diving deep
into these radiation belts

to achieve
one of its key objectives...

mapping Jupiter's
giant magnetic field,

and as Juno swoops
around the planet,

it reveals something scientists
have never seen before.

When you look at the Earth,

we have a fairly
simple magnetic field.

It's like a giant bar magnet
with a north

and south magnetic pole.

Well, Jupiter has that as well.

This is called a dipolar field.

It's got two poles,
but it also has a third pole.

Juno's magnetic field maps

show a north and south pole

and a bizarre magnetic
disturbance at the equator.

And it's like Jupiter
just sprouted a third arm,

and that's kind of mysterious.

On magnetic field maps,

north poles show up red
and south poles blue,

so scientists are calling
this second south pole

the great blue spot.

Everyone knows about
the Great Red Spot,

but Jupiter now has
a great blue spot as well.

This magnetic
disturbance reflects

Jupiter's stormy interior.

You have these fast-moving winds
blowing on the magnetic field,

and they're actually
shearing it apart

and moving the field around.

It's not necessarily a storm,

although it could be.

It maybe is better to think
of it as a magnetic storm.

Turbulence inside
Jupiter could be

twisting up the magnetic field
to drive the great blue spot

and the deadly radiation belts
that Juno must navigate through.

Unlike earth, Jupiter
is not really a solid mass

for the most part,
so all of its clouds and gases

are moving
at slightly different rates,

and that actually makes
the magnetic field

that's generated very variable
and highly changing.

For us to have a variable
magnetic field

like Jupiter does,

the entire earth
would have to be molten.

We really don't want
that to happen.

With each orbit,
Juno unravels more mysteries

of this giant planet,
but Jupiter's deepest secret

could shine a light
on our own origins.

If we want to understand
the Earth

and our place
in the solar system,

Juno has found that a lot
of those mysteries

are locked up there in Jupiter.

The Juno spacecraft

is uncovering
the secrets of Jupiter

from its swirling cloud tops
to its dark heart,

but Juno's discoveries
go beyond the gas giant itself.

They could also solve mysteries
surrounding our own planet.

Jupiter is the key

to the formation
of the solar system,

which means it's the key
to understanding

how the Earth formed.

Juno is actually giving us
a view

into the history
of our planetary system,

even the history of earth.

4.6 billion years ago,

a cloud of hydrogen gas
and cosmic dust collapses,

sparking nuclear fusion.

From the resulting chaos,

one star, four rocky worlds,

and four gassy giants are born

and form our solar system.

There's these distinct zones
of the solar system...

rocky and metallic
in the inner part,

gaseous and water-rich
in the outer part,

and even without thinking
about that too hard,

it kind of makes sense
because in close to the Sun,

it's warmer.

Out farther away from the Sun,
it's cooler.

But the Earth breaks the mold.

Our planet has far more water
than theories predict.

The Earth formed in a part
of the solar system that,

well, you'd think normally
should be probably pretty dry

because it was pretty
close to the Sun.

Our planet is just
150 million miles from the Sun,

putting us inside what
scientists call the snow line.

Inside this line,
the Sun is powerful enough

to evaporate water
during a planet's formation.

Inside the snow line,
the temperatures are high,

and there's a lot of energy
from the Sun nearby.

Too close to the Sun,

those gaseous and ice-rich
materials just can't exist.

They're evaporate away
by the heat of the Sun.

Our watery world
should be a dry rock in space.

Understanding how water got
to the Earth is so important

because it wouldn't be there
in the very, very beginning.

But Jupiter could hold
the answer to this mystery.

To solve the riddle
of earth's water,

Juno aims to discover
where our Jupiter was born.

Understanding how and where

and when Jupiter formed
is critical

because it has really dominated

the entire evolution
of the solar system.

It's the biggest planet by far.

It's the biggest thing out there
that's moving everything around.

Any water in the early
solar system

could've been moved around
by Jupiter's mighty gravity,

so if Juno can trace the history
of this giant planet,

that could explain why we find
H2O where it's least expected.

We know that planets can move
closer to the Sun

and farther out
while they're forming

and even after they form,

so how do we figure out
where Jupiter formed?

The key is how much water is

locked up inside Jupiter.

If we can understand how Jupiter
built a relationship with water,

we can understand
how water got distributed

all throughout the solar system,
including here on earth.

If Juno can measure
the water content of Jupiter,

it will solve
a 20-year-old mystery.

December 1995...

NASA's Galileo probe
begins a fatal dive

into Jupiter's atmosphere.

When it did, it was able to
measure the atmosphere around it

and detect water,
and the thing is... it didn't.

It didn't find any,
and that's weird.

Everything was bone-dry,
so why in the world

did Jupiter's atmosphere
look dry?

If the results from
the Galileo probe are correct,

then 4.6 billion years ago,

Jupiter formed
closer to the Sun,

but that's not the whole story.

20 years later, NASA sends
Juno to get a second opinion.

Juno is an orbiter, and so it
is loaded with instruments

and detectors
to look down on Jupiter

and try to figure out
everything that's going on.

Juno doesn't have to risk

its life to hunt for water.

The craft peers through
Jupiter's thick clouds

using a microwave radiometer to
detect H2O from a safe distance.

Using these microwaves,

Juno builds up a global map
of Jupiter's water.

What Juno has found is, yeah,

there's plenty of water
in Jupiter,

it's just that Galileo
happened to hit a dry spot,

but in fact, if it had
come in almost anywhere else,

it would've seen
plenty of water.

Juno's findings may give a clue

to where Jupiter
originally formed.

It seems apparent now that
Jupiter

didn't form
in its present location.

The leading theory is that

Jupiter formed
just beyond the snow line,

the boundary between
the dry inner solar system

and the wet outer solar system.

But we find Jupiter is twice
as far away from the Sun

as where that original
snow line would've been,

so this is telling us
something interesting.

Jupiter may have wandered from

its original position,

causing unimaginable chaos.

As Jupiter moved around,
things got hit

and knocked out
of the solar system.

It essentially scatters
everything in its path.

It's the biggest player.
It's the biggest planet.

Everything moves for it.

As Jupiter bulldozes
toward the outer solar system,

it slings ice-rich asteroids

and comets in towards the Sun
and towards the Earth.

Jupiter would literally
in some sense

have snowplowed
into the inner solar system

a whole wave
of water-rich planetesimals

that would've delivered
much of our Earth's oceans.

Juno has helped answer
why our Earth is habitable

despite being so close
to the Sun.

So it was worth going all
that distance,

sending Juno all the way out
there to get that closer look.

Juno continues to explore

Jupiter's mysteries
and its famous features.

There is nothing more iconic
about Jupiter

than the Great Red Spot.

And Juno reveals
that this 300-year-old cyclone

may soon vanish.

Our solar system plays host

to some epic natural wonders...

the ice geysers of Enceladus,

the giant rings of Saturn,

the martian mega volcano
Olympus Mons,

but in July of 2017,

NASA's Juno probe skims
the surface of Jupiter

and photographs the most famous
natural wonder...

a fierce, hurricane-like storm

that's been raging
for hundreds of years.

When you think of Jupiter,

one of the most
visually stunning

and most iconic features
of the atmosphere

is that Great Red Spot.

There is nothing like
Jupiter's red spot

in our entire solar system.

As Juno soars
over the Great Red Spot,

it looks down onto a storm
over 10,000 miles across.

This is the most extreme storm.

The winds are
blowing continuously

at 400 miles an hour.

On earth, the most
powerful category 5 hurricanes

can unleash
almost total destruction,

but these are less
than half as powerful

as the storm on Jupiter.

The Great Red Spot is
the greatest hurricane

that you've ever imagined.

But that's not all.

Juno's microwave radiometer
allows scientists to see through

Jupiter's cloud layers
for the first time.

Juno has instrumentation
that's able to look underneath,

so one of the things
we did was we looked

at how deep are the roots.

Juno peers down into the eye

of this monstrous storm.

It spots temperature changes
far below the surface

that follow the storm's
iconic shape,

tracing the roots
of the Great Red Spot

deep into the Jovian atmosphere.

They found out that
it goes down over

200 miles
deep into the atmosphere.

There's nothing
like that on Earth.

The greatest cyclones
of our own planet

can reach heights
of around 10 miles,

but Jupiter's Great Red Spot
is over 20 times taller.

I think that really brings
into perspective

the massive scale
of this planet.

Jupiter's vast,
turbulent atmosphere

hosts the deepest storm
mankind has ever seen,

and Juno's discoveries
get scientists wondering.

Could the Great Red Spot
help explain

another of Jupiter's mysteries,

the planet's surprisingly
warm atmosphere?

Jupiter looks out
in our outer solar system

where everything is very cold.

The Sun is very dim
when you get that far away.

Jupiter is five times farther
from the Sun than we are,

so it's only getting 4%

of the amount of energy
from the Sun that we do.

But there's something heating up

the atmosphere of Jupiter.

There are parts of it
that are many times warmer

than we could explain
with sunlight.

The question is, of course,
where is that energy

coming from?

Juno swoops in for
another pass on Jupiter,

turning its
high-resolution cameras

on the raging storm below.

The storm unleashes
vicious turbulence

into the surrounding atmosphere,

giving scientists the clue
they need

to explain
the planet's high temperature.

The Great Red Spot
is a giant hurricane

that's powered by heat deep
in the core of Jupiter,

but it has such violent
and chaotic motion,

it's mixing up
the atmosphere around it.

The thunderstorms on Jupiter
are gonna be generating

booming thunder
just the same way

that they do here on the Earth.

Thunderclouds send sound waves

rippling through the storm.

A sound wave is a wave
of pressure,

of compression
where air molecules

or water molecules
get compacted.

They get squeezed together,

and when you squeeze
something together,

they're a lot closer together

and they're gonna
get pretty hot.

These sounds waves shoot up

500 miles above the storm

where they break, converting
sound energy into heat.

These sound waves,
they crash together,

creating a tremendous
amount of energy

and heating the gases
around them.

Jupiter's great
red spot has helped heat

the Jovian atmosphere
for hundreds of years,

but new images suggest that
this may be about to change.

Jupiter's red spot is so big,

I mean, it's bigger than earth
by a long shot.

It seems like it would be
an incredibly stable thing.

It's just there and it's always
been there and always will be.

Recently,
we've seen it changing.

When NASA's Voyager
space probe visited

Jupiter in 1979,

it observed a storm
twice the diameter of Earth.

In 2017, Juno's images
show the Great Red Spot

has lost a third of its width,
but that's not all.

Despite the storm shrinking,
it's actually getting taller.

The Great Red Spot is being
stretched and forced

into Jupiter's upper atmosphere.

The storms in
the Great Red Spot,

it's kind of like the clay
on a potter's wheel,

where as you bring your hands
closer together

to draw the clay in,
the closer your hands are,

the taller the pottery becomes,
and similarly, for the storm,

as it becomes
smaller at the base,

it raises taller toward
the upper atmosphere.

It's getting taller,
and we see storms

do the same thing on earth,
and when it does that,

the wind shear will actually
take the top of the storm off

and drag it apart,
and so we'll be watching it

very intently
over the next few years

to see if that's what happens on
Jupiter as well.

It may be only a matter of time

before Jupiter's
high-altitude winds

tear this iconic storm
to shreds.

The most famous storm
of the solar system

may soon disappear,

but Juno reveals other storms

hidden in the strangest
of places.

The storm in the Great Red Spot
is one,

but not the only, giant storm
that's happening on Jupiter.

NASA's Juno probe
has traveled billions of miles

across the solar system

to reveal the mysteries
of gas giant Jupiter,

but there's one part of Jupiter

that has remained hidden
until now.

Before Juno, our view of Jupiter
was very limited.

We'd never actually flown
over the poles.

It's something that's very hard
to do on Jupiter.

We don't have other missions
that have done this.

In August of 2016,
Juno's flight plan takes

the spacecraft
into unknown territory to reveal

Jupiter's mysterious polar
regions for the first time.

Well, and the first time
we looked at the pole,

it didn't look anything
like the Jupiter we knew.

We never would've guessed
that was Jupiter

if somebody had
shown that to us.

Juno's camera reveals
a strange blue expanse

that puzzles scientists.

The electronic color

could be due to chemical changes
in the clouds

brought on by a lack
of sunlight,

but what Juno spots
inside the blue clouds

is even stranger...

giant central cyclones spin
around each pole at 200 miles

an hour, with these cyclones

surrounded by eight
stormy vortices in the north

and five in the south.

There are these weird cyclones,
gigantic swirls,

vortices of gas swirling around
Jupiter's poles,

and they're
clearly forming patterns.

It's hard to get
a sense of scale here.

Now the north polar
central cyclone,

that one right at the pole,
that's 2,500 miles across.

That is almost as big as
the continental United States.

What is going on there?

This is nothing like
what we see on earth.

On earth, our weather
is driven by heat from the Sun

that hits our planet
at the equator

and flows across the surface.

Powerful cyclones form
over tropical waters

and move around the planet,

but the polar regions receive
less energy from the Sun,

so cyclones
can't form at the poles.

We see that if you're at
the equator,

it's warmer and it's stormier.

If you're at the poles,

where the Sun is slightly harder
to see, that activity goes away.

But the weather on Jupiter

couldn't be more different.

We see lightning
and convective thunderstorms

at the poles of Jupiter
but not at the equator,

and that's sort of the opposite
of what we see on the Earth.

The question is,
what's driving Jupiter's storms?

Jupiter is five times further

away from the Sun than the Earth

and receives only a fraction
of the Sun's energy.

Unlike earth,
Jupiter's polar regions

seem to be where the action is.

Something is driving
the planet's weird weather,

and Juno's scans of the giant
planet's thermal emissions

suggests it could be
Jupiter itself.

We can actually see
the internal heat of Jupiter

coming right up through,

and so Jupiter
will look very bright in areas

where we can see that heat.

Juno detects searing heat

beneath Jupiter's cloud bands.

Jupiter has so much material,
so much mass,

so much gravity that
the interior is incredibly dense

and very, very hot.

At the core, it's probably at
many thousands of degrees hotter

than the surface of the Sun.

This fiery inferno
buried in Jupiter's dark heart

is a relic from its birth
billions of years ago.

The violent collisions
that formed the planet

left its core seething hot,

a heat that remains to this day,

buried under thousands of miles
of insulating gas.

As the heat slowly leaks
outward,

Jupiter's fast-rotating
atmosphere

creates vicious cyclones
and thunderstorms.

And that's what's really
driving most of the weather.

It's not the Sun.
It's Jupiter itself.

And as Juno soars
over the planet,

it reveals
another weather mystery.

The craft detects bursts
of radio waves

spiking up
to four times a second...

the telltale sign
of ferocious lightning strikes.

Clouds are moving around
in the atmosphere

and building up electric charge

and causing bolts
of lightning to form,

and we've actually seen this
with the Juno spacecraft.

These are mega storms
orders of magnitude bigger

than here on Earth.

And Juno finds there's
more to these thunderclouds

than just flashes of light...

giant icy hailstones of water
and ammonia,

the chemical
which gives Jupiter's clouds

their orange color.

High up in Jupiter's atmosphere,

the ammonia is mixing
with the water,

and it becomes a liquid ball

that starts to collect ice
around it,

and it will fall like hail does
deep into Jupiter's atmosphere.

On earth, hail falls
to the ground and melts,

but on Jupiter,
there is no ground.

And it gets lifted
in the atmosphere

because of an updraft
and then more ice,

and it builds bigger,
and then it falls down,

and then it gets
carried back up,

and so hail is often
many layers being built.

These ice balls grow
layer by layer as they soar up

and down the atmosphere.

If they formed in storms
here on earth,

they'd cause
some serious damage.

So if you were buzzing around
Jupiter

and you were near
where these storms were,

you might get hit by hail
coming up or going down.

This is one of the most violent,
energetic atmospheres

in the entire solar system.

Juno is revealing the secrets

that Jupiter has hidden
for decades,

including the mystery
of Jupiter's northern lights.

When Juno studied the lights

coming from the aurora
on Jupiter,

it found that something
really weird is going on.

On earth, dazzling
auroras light up the skies

as charged particles
from the Sun

interact with atoms high
in the atmosphere.

Deep in the outer solar system,
Jupiter is too far from the Sun

for strong auroras
to form in this way,

but high above
the giant planet's poles,

Juno spots a seemingly
impossible light show.

The auroras of Jupiter
are tremendously larger

than the ones
that we find here on Earth.

In fact, the auroral rings
near the poles

are bigger
than our planet itself.

Jupiter's auroras emit

primarily ultraviolet
and X-ray light,

so you can't see it
with the naked human eye,

but if you could see them
and you were at Jupiter,

that would be
an amazing light show

because those auroras
are strong.

These glowing displays are

evidence of charged particles

slamming into
Jupiter's atmosphere.

But if they're not coming
from the Sun,

where are they coming from?

Hunting for an answer,
Juno snaps an image

of Jupiter's southern lights

with its ultraviolet
imaging spectrometer.

Inside the aurora,
it glimpses something strange.

When Juno studied the lights

coming from the aurora
on Jupiter,

it found that they were
even stronger than expected,

and in fact, when you look at

Jupiter's poles in wavelengths
that our eyes can't see,

for example, ultraviolet,
you see a hot spot.

This hot spot marks the point

where huge concentrations
of charged particles

strike Jupiter's atmosphere.

Tracing their trajectory
reveals the culprit

of Jupiter's dazzling
light shows...

the volcanoes
of Jupiter's moons.

Jupiter's moon, Io has hundreds
of active volcanoes

spewing out materials
way out into space,

and many of those get trapped by
the magnetic field of Jupiter.

Io's volcanoes fire
out jets of charged particles,

which are swept by the giant
planet's magnetic field.

It's funneling those
particles down

and slamming into specific spots
in Jupiter's atmosphere.

But Io isn't
the only moon responsible

for Jupiter's polar light show.

If we go further out,
Europa, Ganymede,

Callisto, those are more icy.

They don't necessarily
have volcanoes.

These icy moons twist up

Jupiter's magnetic field
in their own way.

Some of these moons have
magnetic fields that interact

with Jupiter's magnetic field,

and that actually intensifies
the aurora display on Jupiter.

Jupiter's moons work together

to energize the greatest auroras
in the solar system,

but in these beautiful displays

is a stark reminder
of the danger Juno faces.

When you look at these pictures
of the aurora on Jupiter,

and you think,
oh, that's beautiful.

Wouldn't it be great
to see that in person?

The answer is no,
no, it wouldn't

because they will kill you.

What's causing these displays
are subatomic particles

accelerated to tremendously
high speeds

by the magnetic fields involved.

The radiation around
Jupiter is lethal

and not just for humans.

The lifetime of the Juno
mission is very limited

by the extreme conditions
it has to survive in.

We think that in the future,

a lot of the instruments
will be so irradiated,

they won't really work anymore.

When Juno's titanium
armor finally fails,

Jupiter's deadly radiation will
damage the craft beyond repair,

so the team plan to go out
with a bang,

thrusting Juno into
Jupiter's atmosphere,

where the craft
will be torn to pieces.

Eventually, it'll be drawn down
into Jupiter's depths

and become a part
of the planet itself.

But before then,

Juno has many
more mysteries to unlock.

We'll answer some questions,
and we'll raise some more.

That's what I expect

and we'll get some
fantastic images.

Every single thing has turned
out to be a surprise.

There are so many things that
Juno has opened our eyes to that

I can't imagine
having not sent it.

So we're in for at least a year

more of the most profound
surprises about Jupiter.

What we're learning,
what we're unlocking,

not just about Jupiter,

but the formation
of the solar system

and potential formation
of life itself

here on earth,

it's mind-blowing.

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