All language subtitles for How.The.Universe.Works.S08E01.When.NASA.Met.Jupiter.1080p.AMZN.WEB-DL.DDP2.0.H.264-alfaHD_track4_[eng]

NASA's revolutionary Juno probe

is on a daring voyage to Jupiter.

Its goal, to reveal 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.

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 don't 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
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 towards Jupiter,

gravitational spikes tug at the
craft.

It 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's 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 centre 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 centre 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 are describing 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

twenty 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 centimetre-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 absorbed 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 the 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 starts sucking in all
nearby hydrogen gas...

building the iconic 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 launches

a billion-dollar mission
to uncover them.

MAN: Three, two, one, ignition.

And lift-off 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 per 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.

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...

it's 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?

(LAUGHING)

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 per hour.

(CHEERING)

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 critical 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.

To reveal the true scale of Jupiter's
magnetosphere,

planetary scientist Jani Radebaugh
hits the beach.

I've made a little solar system.

So we'll start here at the sun.

We come out here to the Earth.

And now we're going to skip a few
and go out to Jupiter.

And Jupiter is five times as far
away from the sun as the Earth.

Now, we'll go out to Saturn.

Saturn here is ten times as far away
from the sun as the Earth.

And we want to look at the size of
Jupiter's magnetic field.

So we want to draw out the magnetic
field of Jupiter.

It arches around like this...

away from the sun because
the solar wind is impacting
the magnetic field,

dragging it downwind.

So here it comes downwind.

On both sides.

All the way out to the orbit of
Saturn.

Jupiter's magnetosphere stretches

over 600 million miles beyond the
planet.

When you think about structures in
our solar system,

of course,
you think of the giant sun,

you think of massive planets like
Jupiter...

But what if the largest things in
the solar system are things we
really can't see.

And in fact the magnetic field of
Jupiter

and all of the particles trapped
in it

are one of the largest things the
solar system has to offer.

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.

As Jupiter is bombarded by the solar
wind,

high-energy particles from the sun

are funnelled 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.

Close to the planet, radiation levels
are up to 30 times greater

than 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 too.

The charged particles threaten to
destroy

electronic and navigational systems,

but Juno has armoured 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, like an
armoured tank going into war.

Lightweight titanium is tough.

Juno's half 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.
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.

Planetary scientist Dan Durda
demonstrates.

We can use a pretty simple, even
elementary school level experiment

of the structure of the Earth's
magnetic field

by shaking some iron filings

across the surface

of very simple bar magnet
with a north and south pole.

Earth's magnetic field forms a
perfect bubble around our planet,

protecting us from solar radiation
and cosmic rays.

If I can get these little iron
fillings to come out here...

And already I can see,

the sort of classic outlines

of the north and south magnetic
field lines that are coming out
of our planet.

The Earth's magnetic field is pretty
well behaved in this way. It's what
we call a dipolar field.

It has a very distinct north and
south magnetic pole.

Lucky for us, Earth's magnetic field
is pretty stable.

But new results from Juno suggests
that Jupiter may not be so fortunate.

Jupiter's magnetic field is much
more complex than this.

Jupiter is not going to play by
those rules.

Its magnetic fields are going to do
whatever it wants.

And the generation of that magnetic
field

is so complex
and so twisted and and so wild

that the magnetic field is gonna
have very strange shapes

that we're just now beginning to
understand.

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

shows a north and south pole

and a bizarre magnetic disturbance at
Jupiter's 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 of Jupiter,

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 answer mysteries about 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 mammoth 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

to 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 cos getting
close to the sun, it's warmer.

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

But the Earth breaks the mould.

Our planet has far more life-giving
water than theories predict.

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

you'd think normally should be
probably pretty dry

cos 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 evaporated 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
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 have been moved around by
Jupiter's mighty gravity.

So if Juno can trace Jupiter's
history,

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.

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 so it's loaded
with instruments and detectors

to look down on Jupiter and try to
figure out everything going on.

Juno doesn't have to risk it's life
to hunt for water.

The craft pierced through Jupiter's
thick clouds

using a microwave radiometer

- to detect H2
- O 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 scientists
a clue

to understanding 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 towards
the outer solar system,

it slings ice ridged asteroids
and comets

in towards the sun and towards Earth.

Jupiter would literally,
in some sense,

have snow ploughed 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 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.

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, 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,

most iconic features of the
atmosphere is the 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.

Earth's most powerful Category Five
hurricanes

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
monster storm.

It spots temperature changes 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

Weather satellites circling the Earth
show the greatest

cyclones of our planet
can reach heights

of around ten miles.

But Jupiter's Great Red Spot is 20
times taller.

I think that really brings into
perspective

the massive scale of this planet.

The dizzying depths of the storm is
made possible

by Jupiter's vast hidden atmosphere.

A seemingly endless spinning mass

made up of hydrogen and helium.

Jupiter doesn't have a solid surface
like the Earth does.

And so right away, if you were to
dive into Jupiter's clouds

things are gonna be really
different. This atmosphere's
tremendously thick.

As you're going in
the pressure is going up.

As soon as you start plunging down
into that atmosphere

there's more and more.
There's not just a 100 miles of air,

there's a 1,000 miles of air,
10,000 miles of air above you.

And not only would your ears pop
deep in the Jovian atmosphere,

your entire body would pop

and, in fact,
all of your molecules would pop.

Juno's vast turbulent atmosphere

hosts the deepest storm
mankind has ever seen.

And Juno's discoveries

gets scientists wondering...

Could the Great Red Spot

be behind another of Jupiter's
mysteries,

the planet's surprisingly warm
atmosphere?

Jupiter lurks 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 four percent 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 can
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 thunder storms on Jupiter are
gonna be generating booming thunder

just the same way they do here on
the Earth.

Thunder clouds and 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.
When you squeeze something together,

they are lot closer together and
they're gonna get pretty hot.

These sound waves shoot up 500 miles
above the storm

where they break,
converting sound energy into heat.

The sound waves,
they crash together

creating tremendous amount
of energy, heating the gases
around them.

The 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, 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 it 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 the Earth.

In 2017,

Juno's images showed the
Great Red Spot

has lost one-third of its width.

But that's not all.

Despite the storm's shrinking size,

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
is 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 to 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 take the top of
the storm off and drag it apart.

So we'll be watching it 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 the iconic storm to shreds.

The most famous storm of our solar
system may soon disappear.

But Juno reveals other storms

hidden in the strangest of places.

NASA's Juno probe has voyaged

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, 2016,

Juno's flight plan takes the
spacecraft into unknown territory

to reveal Jupiter's mysterious Polar
regions for the first time.

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 puzzle scientists.

The electric colour 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 per 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.

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.

It 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, 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.

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

Question is, what's driving
Jupiter's storms?

Jupiter is five times further from
the sun than the Earth

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

And 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 thermo emissions

suggest it could be Jupiter itself.

You 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 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

leave its core seething hot,

a heat that remains to this day,

buried under thousands of miles of
insulating gas.

As the heat slowly leaks outwards,

Jupiter's fast rotating atmosphere

gets churned up into vicious cyclones
and thunderstorms.

That's what's really driving most of
the weather.

It's not the sun,
it's Jupiter itself.

And as Juno soars above the planet,

it reveals another weather mystery.

The craft detects bursts of
radio waves,

spiking up to four times a second,

a tell-tale sign of ferocious
lightning strikes.

Clouds are moving around
in the atmosphere, 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 that there's more
to these thunderclouds

than just flashes of light,

giant icy hail stones of water
and ammonia,

that chemical which gives Jupiter's
clouds their orange colour.

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.

But on Jupiter, there is no ground.

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.

So hail's often many layers
being built.

These icy 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 Jupiter's hidden
secrets.

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's 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
we find here on Earth.

In fact, the aurora rings at 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 powerful
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 fired of
Jupiter.

Io's volcanoes

fire out jets of charged particles

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

It's funnelling 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,

don't necessarily have volcanoes.

These icy moons twist up Jupiter's
magnetic field.

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
energise

the greatest northern lights 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,

"That's beautiful. Wouldn't it be
great to see in person?"

The answer is, "No. No, it wouldn't.
Because they would 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.

The lifetime of the Juno mission is

very limited by the extreme
conditions it has to survive in.

We think that in the future
all of the instruments

will be so radiated
they won't really work any more.

When Juno's titanium armour fails,

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

So the team plans to go out
with a bang,

thrusting Juno into Jupiter's
atmosphere

where the craft will be torn apart.

Eventually it will be drawn down
into Jupiter's depths

and become a part of the planet
itself.

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're 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 the potential formation of life
itself here on Earth...

It's mind-blowing.

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