All language subtitles for A.Travelers.Guide.to.the Planets.S01E05.Neptune.&.Uranus.2010.1080p.BluRay.DD5.1.x264-c0kE_track3_[eng]

MAN: T minus 40 seconds.
Everything looks good for launch.

NARRATOR: Got time
for a 24-year vacation?

Then consider a journey

to the most distant planets
of our Solar System.

WOMAN: The rest of the solar system
beyond the asteroid belt

is really where it's at.

NARRATOR: They are two
giant worlds of icy gas.

And one of them has a funny name.

WOMAN: I pronounce
the planet's name YOOR-a-nus.

NARRATOR: From orbit,
Uranus appears sedate and calm.

But why is the planet on its side?

And Neptune--the second blue planet,
and the last world in our solar system.

So far from the sun, you wouldn't expect
much to be happening here.

But something is driving its wild winds,
the fastest in the solar system.

And what became
of its Great Dark Spot?

WOMAN: So this planet
just changes its spots.

Leopards don't,
but Neptune does.

NARRATOR: Uranus and Neptune:
the ice giants.

Strap yourselves in
for an incredible voyage

to the most remote and
intriguing planets of all.

There has never been
a better time

to boldly go where no human
has gone before,

to follow in the footsteps
of our robot pioneers

and visit the planets
of the solar system.

MAN: T minus two minutes and counting.

MAN: Go at throttle up.

NEIL ARMSTRONG:
That's one small step for man...

MAN: Oh, man, that's incredible!

NARRATOR: Ever wanted to be
an astronaut?

Imagine heading into the ice zone,

the frigid, dark realm
beyond the orbit of Saturn.

To travel here means undertaking
a voyage of epic proportions.

Think of this as your personal travel guide
to the outer solar system.

First stop, Uranus.

At first glance, the seventh
planet from the sun

appears as an unmeasurable ball
of green-blue fog.

But slip below Uranus' icy veil

and you encounter a world
seemingly without end...

because this is a planet
made almost entirely of gas:

hydrogen, helium
and a splash of methane

that gives the planet its color.

TORRENCE JOHNSON: It's actually
very difficult to describe to people

what it feels like in the interior
of these gas giant planets

because it's so far
from our terrestrial experience.

NARRATOR: The third largest planet
has at least 13 rings.

But unlike the broad bands of Saturn,
these are thin and dark.

No one's quite sure
how they formed,

but they could be
the result of collisions

between its small army
of at least 27 moons.

But Uranus' most striking feature
is its lopsided tilt.

It's the only planet in the solar system
to orbit on its side,

resembling a giant bull's-eye.

How did it end up this way?

The answer may surprise you.

HEIDI HAMMEL: I'm fascinated
by Neptune and Uranus

because we know so little
about these planets.

We've only ever had
one spacecraft visit them,

and it was a very brief flyby.

NARRATOR: Astronomer Heidi Hammel
is driving to the ice giants--

well, about as close as you can get
to them on planet Earth.

HAMMEL: The most exciting thing
about Uranus

is that it's completely tilted
over on its side.

Its atmosphere changes radically,
depending on the season.

And it has a really interesting
thin ring system.

So that's the cloud, and these,
of course, are the rings.

It's a nice image of Uranus.

NARRATOR: Although separated
by 1.6 billion miles,

one of the world's highest telescopes
is watching the planet spring into life.

HAMMEL: Uranus has been going through
a very special season that we call equinox.

The north polar part
that's coming into sunlight

for the first time in two decades

is turning on with all kinds
of dynamic cloud activity,

none of which was expected
or predicted.

So it's very exciting to get this data

and basically be rewriting textbooks
about the Uranus system right now.

We're very happy astronomers.

NARRATOR: For the first time,

this far-flung outpost
is being seen in a new light.

And when it comes to image,
it's not a moment too soon.

That's because, for most of us,
Uranus is the butt of a big cosmic joke.

ANDY INGERSOLL:
| pronounce it YOOR-a-nus.

| think people are embarrassed
by Your-ANUS.

CAROLYN PORCO: YOOR-a-nus.

Yeah.

HAMMEL: | pronounce
the planet's name YOOR-a-nus,

which is very likely closer
to the original pronunciation

of the name of the god
after whom it was named.

NARRATOR: If you think "Uranus"
is a funny name for a planet,

then you may prefer
its first name--

"George."

Discovered by William Herschel in 1781,

he christens his new find "Georgium Sidus"
after the King of England, George Ill.

But the custom of naming planets
from ancient mythology prevails,

and Planet George is no more.

And it's very likely that Uranus
would have remained

nothing more than a green-blue blotch
at the end of a telescope

if it wasn't for a really bright
rocket scientist...

and a little bit of luck.

GARY FLANDRO: A lot of people
were saying back in the ‘60s

that it would be impossible for us

ever to explore those distant planets--
too far away.

NARRATOR: As an intern at
the Jet Propulsion Laboratory in California,

Gary Flandro is given the task

to investigate a journey
to the outer planets.

FLANDRO: So | started drawing
pictures of the solar system.

And in that process | noticed
that all of the outer planets

turned out to be about the same alignment
relative to the Earth in the late '70s.

So | saw that | could
almost draw a ruler

between Jupiter, Saturn,
Uranus, Neptune.

Pluto was not cooperating,
but that seemed not to be a worry.

NARRATOR: This mathematical sleuth work reveals a
rare window

where the planets are
perfectly aligned for a visit.

EDWARD STONE: There's an opportunity
every 176 years

for a single spacecraft to fly
by all four giant planets.

That was 1977, and so we created
the Voyager mission to start on that journey.

FILM NARRATOR: A complex package
of experiments called Voyager

is designed to take the first thorough
close-up look at the giant outer planets.

NARRATOR: In an extraordinary feat
of engineering,

teams build two spacecraft
in just 12 years

and pushed the existing global network
of ground stations to new heights.

JOHNSON: The outer solar system
is called "outer" for a reason.

It's a long way away.

PORCO: The rest of the solar system
beyond the asteroid belt

is really where it's at.

And so that's what Voyager did.

Voyager showed us
what was out there.

NARRATOR: On board,
there's even a gold record

containing a greeting from Earth,

should the spacecraft encounter
any friendly aliens.

CHILD: Hello from the children
of planet Earth.

WOMAN: Bonjour, tout le monde.

WOMAN: Kon'nichiwa.
O genki desu ka?

MAN: Hola y saludos a todos.

STONE: We knew the Voyagers were going
to be the first to reach interstellar space,

so we felt that this was
sort of an announcement from Earth

that we were now able to send a message
away from our solar system

into orbit around the center
of our own galaxy.

NARRATOR: Launched
a few weeks apart in 1977,

the twin Voyager spacecraft
embark on their epic journeys,

known as "The Grand Tour."

PORCO: It was a first, it was historic.

Just being part of the whole mission,
being part of this tremendous enterprise,

the first time in human history
we are seeing these bodies up close

was a thrill.

NARRATOR: What would it be like
to follow in the footsteps of Voyager,

to experience one of the greatest journeys
in space exploration?

63 times larger than the Earth,

here you'd be lucky
to celebrate a single birthday.

The planet takes 84 years
to make its way around the Sun.

Uranus and sister Neptune
are known as the "ice giants"

because of their frigid
outer atmospheres,

super-cooled to minus 355 degrees
Fahrenheit.

But the biggest, most obvious feature
about Uranus is its crazy tilt.

However, it wasn't always this way.

JOHNSON: The traditional explanation
was that while Uranus was forming

it may have been hit by a larger chunk
of accreting material than normal

and actually knocked it over
on its side.

The problem is, when you do
the maths on this, it doesn't work.

It's very, very difficult
to get a large enough body

traveling fast enough to be very credible
at knocking Uranus over on its side.

NARRATOR: Rather than being pounded,

it's now thought that Uranus
may have been swept off its feet

by the gravitational tugs
of its giant neighbors.

JOHNSON: Uranus' tilt actually results
from rather complicated interactions

with Saturn, Neptune and Jupiter, even.

All of these planets do have
gravitational effects on one another,

and the effects are more subtle
than we used to think.

And it's dynamics,

not a big smack in the face
from a large impacting planetesimal.

When Voyager journeys
to the outer solar system in the 1970s,

it beams back astounding images of Jupiter,
Saturn and many of their moons.

STONE: The wonderful thing
about the Voyager mission,

we saw so many things
for the first time,

and they were all so different,
so diverse and distinctive.

JOHNSON: Being there
when the images are coming in

makes you feel like you're on the bridge
of the Starship Enterprise.

Because you really feel like you're there,
those are just your sensor screens,

and you're getting reports back

from these alien worlds
that you're taking a look at.

WOMAN: Who could ever have
enough pictures of Saturn's rings?

NARRATOR: So what do Voyager's cameras reveal of
Uranus, the lopsided planet?

JOHNSON: Well, Uranus was
a real enigma for us.

So we didn't know what to expect.

NARRATOR: In 1986, after a decade
of traveling through space,

there are great expectations
for the seventh planet from the sun.

BONNIE BURATITI: From the Earth
it looked kind of bland.

And quite frankly, from Voyager
it looked kind of bland, too.

HAMMEL: The images of Uranus
were a little bit disappointing.

STONE: It's a very bland planet
with very few clouds.

FLANDRO: Not much going on
at Uranus.

NARRATOR: These are the first images
of Uranus, taken from Voyager 2.

The planet appears as still as a pond
with no cloud detail at all.

And it's silent.

JACK CONNERNEY: We did not hear a whisper
from Uranus before the Uranus encounter.

NARRATOR: Unlike Jupiter,

whose magnetic field roars
across the radio waves,

at first Uranus
doesn't make a peep.

CONNERNEY: Part of that was
because the radio source

was on the other side of the planet
where the strong magnetic fields are.

And they were beamed
away from the spacecraft.

NARRATOR: Voyager discovers that
Uranus’ magnetic field is wildly off kilter.

Planetary magnetic fields require
the movement of charged particles.

On Earth, this occurs
in our molten iron core.

So what's driving
Uranus' magnetic field?

There's more going on here
than meets the eye.

Just what lies below
Uranus' veil of clouds?

To find out means clearing
your calendar for the next 24 years

and surviving a flight from hell.

You've escaped the clutch
of Earth's gravity,

the first step on your voyage
to the outer solar system!

Now, the seatbelt sign is off,
but your problems are just beginning.

Zero gravity may look fun,
but when it comes to human biology,

we're simply not designed to be
in the weightlessness of space.

VOLKER DAMANN: If there is no gravity,

then there is no need for the heart muscle
to pump the blood upwards,

so the heart muscle doesn't need
to work as hard, so it's de-conditioning.

The same happens
with all the muscles.

If you are not working and exercising
and working against the drag of gravity,

you're de-conditioning.

NARRATOR: From this control room
in Germany,

a medical team scrutinizes the health
of the European astronauts

aboard the International Space Station.

DAMANN: The astronauts work out
roughly two hours per day.

It's a mandatory physical exercise
that we prescribe.

Some people like more to ride the bicycles,
others like to use the treadmill.

NARRATOR: Zero gravity for 24 years?

That two-hour daily workout
will soon get pretty tedious.

The fact is, no one
really knows what effect

two dozen years of weightlessness
will have on the human body.

No one has ever been
in space that long.

KEVIN FONG: Human missions to
the outer planets are going to take years,

maybe more than a decade.

And none of these places
support life on their own.

You're going to take everything
that you need with you.

You're going to need to take your food,
your water, your light, your heat,

your power, your atmosphere,
and that's a tricky thing to do.

NARRATOR: And the one item you'll need
more than anything is water.

KAREN PICKERING: If you were just
to put everything you need in a box

and take it to space
with you for a year,

about 90% of the mass
you need is water.

NARRATOR: To solve the problem, NASA
has been working on its recycling systems.

But it may not suit everyone's taste.

PICKERING: We take waste water streams
from a variety of sources.

We take hygiene water
from your showers,

washing your hands,
brushing your teeth, urine, of course.

And then we can choose
several different processes

to bring that waste water clean enough
that we can drink it again.

The clean water tastes just like water
you'd buy in the grocery store,

though it's distilled, so it doesn't
taste as good as the water from your tap

because there's no minerals in it.

But it doesn't taste like waste water,
like you know where it came from.

NARRATOR: So with your thirst quenched, you're on
your way.

Sit back and relax
for the next ten years.

From orbit, Uranus gives little away.

But plunge below
its placid-looking clouds

and you encounter a world
that's anything but.

HAMMEL: So let's imagine | was riding
an atmospheric probe

that's being sent down
into the planet Uranus.

NARRATOR: Open your
spacecraft window here,

and you'll quickly feel where
the ice giants get their name.

In the upper atmosphere, frozen crystals
of methane mix with hydrogen and helium.

HAMMEL: We might pass
some of these towering anvil clouds

that we know are there.

And as we looked at those
we would look for the lightning,

we would listen for the thunder
that would accompany them.

NARRATOR: Freefalling here is like
descending into a giant green gelato.

But the deeper you go,
the thicker and hotter the atmosphere.

Temperatures heat up
to thousands of degrees,

heat left over from
when the planet formed.

STONE: Eventually
the pressure just builds,

and the gas becomes basically
a fluid or a liquid.

And there's no real transition,

it's just a continuous increase
in pressure and density.

NARRATOR: Keep descending
and you'll soon start to boil

in a seemingly bottomless sea,

more than 2,000 times deeper
than the Pacific Ocean.

Somewhere down here, a little more
than halfway to the planet's center,

Uranus' lopsided magnetic field
flutters into life.

CONNERNEY: If you could see
down to the surface of the dynamo core,

where the field is generated,

what you might see
is parcels of fluid moving about.

And they're generally so conductive

that those parcels of fluid
would drag field lines with them.

NARRATOR: Why Uranus' magnetic field
is generated here,

and not in the core,
no one really knows.

No person or robot
has ever been down here.

HAMMEL: If we could get even further
we might get to a core, but we're not sure.

Isn't that interesting?
We aren't sure if Uranus has a core.

NARRATOR: Down here,
one thing is certain:

with a planet-load of water and gas
on your back,

and in temperatures of
more than 4,200 degrees Fahrenheit,

no life, or robot, will last long.

JOHNSON: There would be no chance
of surviving under those conditions.

A probe going into the atmosphere
would eventually actually evaporate

and become part of the atmosphere
that it was studying.

NARRATOR: Not enthused
about the prospect

of being crushed and boiled alive
by a giant ball of gas?

Don't worry, there's still
plenty more to see and do.

Cruise above the skies of Uranus,
and take your pick of 27 moons,

most named after characters
from Shakespeare.

HAMMEL: If | were to take a tourist trip
to the Uranus system,

| would go to Miranda.

NARRATOR: Only 290 miles across,

moon Miranda is about as wide
as the state of New York.

But the geography here
is stranger than anything on Earth.

JOHNSON: It's an interesting
sort of jigsaw puzzle moon.

It looks like it's been
put together by a potter

with not paying too much attention
to his materials.

It's got chunks of this
and chunks of that,

that sort of look like
they are slapped together.

And frankly we still don't
really understand Miranda too well.

NARRATOR: When Voyager
first spots Miranda,

no one is sure what to make of it.

ROBERT PAPPALARDO: When the images
came back of Miranda,

the first ideas were that Miranda
was somehow shattered by a huge impact,

broke up and came back together.

NARRATOR: But now scientists
think that the moon

may be caught in the middle
of a cosmic makeover.

PAPPALARDO: In the early stages
of a satellite's history,

the satellite is differentiating.

The rocky bits are falling
to the center,

and the icy bits are lower density
and moving outward.

And so maybe that's what we're seeing--

Miranda sort of frozen in,
in a state of differentiation.

NARRATOR: The result:
a part-finished lunar construction zone,

with some pretty impressive
sites to visit.

JOHNSON: Miranda's got
some spectacular ice cliffs on it

that you could sit on the top of
and look down for five or six kilometers.

NARRATOR: Think the Grand Canyon
is impressive?

On Miranda, these cliffs
are at least three times higher.

PAPPALARDO: If you were
to jump from it,

because of the very, very low
gravity of Miranda,

it would take minutes to slowly fall
down to the surface.

JOHNSON: With this nice blue fuzzy ball
of Uranus in the background,

it might be pretty scenic.

NARRATOR: And while you're here,

it's hard to ignore Uranus'
other tourist attraction,

its collection of 13 razor-thin rings.

HAMMEL: Uranus' main rings
are very tightly confined

with a lot of space in between them,
sort of like a series of hula hoops,

increasingly large hula hoops
moving away from Uranus.

NARRATOR: How these rings form,
no one's completely sure,

but they could be the result
of a cosmic demolition derby.

BURATTI: The five major satellites
of Uranus

are in pretty regular orbits,
and they are stable.

But some of the other objects,
especially the outer satellites of Uranus,

scientists have been working
on computer models

that show they do frequently collide.

And if they get too close to Uranus,
they could break apart.

And of course Uranus does have
a very complex family of rings

that we believe is
broken-up satellites.

NARRATOR: For the planet that's
always been the butt of everyone's joke,

perhaps it's only fair
that it has the last laugh.

That's because Uranus' best view
is its rear end.

LINDA SPILKER: As we were flying
out from Uranus,

we were looking back
and looking at the rings

at what we call "high phase angle."

It's equivalent of if you have
a dusty windshield

and you drive into the afternoon sun,
the dusty particles light up.

So, too, in the Uranus system.

| remember sitting there
as that picture came down,

you know, line by line
and played out,

and just the joy that, "Oh, my goodness,
we didn't know

there was something quite so
spectacular to see there at Uranus."

NARRATOR: Take a good last look,

as there's nothing more to see
for three more years...

until you arrive at Neptune.

Make sure you have plenty
to keep you busy;

being cooped up in a tin can
is sure to play tricks on your mind.

FONG: Out in space, separated
by such great distances,

you need to start thinking
about the psychology

of the space environment.

You're going to be
in a close, confined environment

with almost no privacy.

Death is always going to be
just a hull's thickness away,

and you have to start thinking about
how you can stop your crew's going crazy.

ASTRONAUT: Wooh!

[applause]

NARRATOR: The possibility
of going crazy

is something these space travelers
know all about.

MAN: Congratulations
to the explorers,

to the mission organizers
and to the scientists.

NARRATOR: The heroic welcome

is to celebrate their return
from a 105-day space mission.

Only thing is, they haven't
traveled an inch.

SIMONETTA DI PIPPO:
The Mars 500 program

is a simulation project
of a mission to Mars.

What we would like to do
is to simulate the time delay,

the confinement, the psychological
and physiological aspects.

NARRATOR: Sealed away
in this Moscow warehouse,

the crew lived every day

as if they were on
a long-haul space flight for real.

Watching closely, a team
of psychologists and doctors

who monitored every aspect
of their mental health.

OLIVER KNICKEL: It was
not always easy to stay

in such a confined area
for such a long time.

So you always felt kind of limited,

since the space is just limited.

You didn't have the sunlight,

you didn't have the nature.

So this had quite
an impact on the crew.

NARRATOR: The psychological effects
from this mission of the mind

are still being analyzed.

No one seemed to go crazy
on this mission.

But on a voyage to the ice giants,
if the isolation doesn't make you insane,

the menu might.

KNICKEL: In order to keep us healthy,

and we hardly had any
fresh fruits or vegetables,

we ate this baby food here.

Which might not be the usual food
you have in your usual life,

but at least it's kept us healthy,

and | didn't even think
it tasted too bad.

NARRATOR: 105 days eating baby food
is certainly an achievement.

But who is going to do that
for 24 years?

Moving out from Uranus
is its ice sister, Neptune,

another mysterious ball
of frigid gas.

PORCO: Unlike Uranus, Neptune
was immediately beautiful.

Especially when we started
to produce color pictures,

because it had this
blue-green atmosphere

and these white clouds floating
in the atmosphere.

So you couldn't help,

at least | couldn't help
but be reminded of the Earth.

NARRATOR: At 30 times the distance
of the Earth to the sun,

the star appears not much more
than a glimmering point of light.

Out here, the days pass quickly,
each 16 Earth hours long.

But you'll need a thick calendar,

with around 90,000 days
to a Neptunian year.

That's 165 Earth years
to orbit the sun.

Like its neighbor, Neptune is
a giant ball of hydrogen and helium,

its color courtesy
of a bit of methane.

But it's so blue here that some
other chemical mixture is at work.

HAMMEL: In fact, there's something
in the clouds of Neptune

that is causing its vivid blue color,

and we don't know what that is yet.

It's one of the mysteries
that we're trying to solve

by studying Neptune with our telescopes
on the ground and in space.

NARRATOR: And that's not
the only mystery:

Something is driving
Neptune's wild winds,

the fastest in the solar system.

And why do Neptune's spots vanish
almost as quickly as they appear?

JOHNSON: As we were
approaching Neptune,

and it was getting larger and larger
in the TV screens

in the Voyager project area,

the thing that really got us
going very rapidly,

we noticed that Neptune had
something that Uranus didn't,

which was a big spot
in its atmosphere.

INGERSOLL: Voyager saw
several spots,

the biggest one we imaginatively
called "The Great Dark Spot."

JOHNSON: It kind of was like watching
a blob of ink in swirling water.

NARRATOR: About the size of Earth,

the Great Dark Spot is actually
a massive hole,

a window to the darker clouds below.

HAMMEL: So a swirling storm that
cleared out a hole in the clouds,

allowing us to see
down to deeper layers.

It didn't give the appearance
of being stable.

It sort of gave the appearance
that at any moment it could fall apart.

And so we weren't all that surprised
when within five years it had disappeared.

NARRATOR: In 1994, when NASA
turned Hubble, its orbiting telescope,

towards Neptune,
its Great Dark Spot had vanished.

HAMMEL: So this planet
just changes its spots.

Leopards don't, but Neptune does.

It dramatically changes its spots
on timescales of just five years.

That was a surprise
that Neptune changes so quickly.

It's a different kind of planet.

NARRATOR: Since then other spots
have come and gone.

No one is sure why,

but it could have to do
with Neptune's wild equatorial winds.

Take a leap into
Neptune's atmosphere,

and you'll be surfing the fastest skies
in the solar system.

This wind tunnel in Los Angeles

is barely a ripple of air
compared to Neptune's winds.

Because on the last planet
in the solar system,

winds roar around the equator
at nearly twice the speed of sound.

INGERSOLL: What drives the weather?
There's two things.

One is the sun,
just kind of like the Earth,

although the sun
is pretty weak at Neptune.

And then Neptune
has some leftover heat.

And the heat comes out
as warm gas.

When the planets formed,
all this material came crashing together.

And that crashing together
generated heat.

And some of that heat is still there
buried down inside Neptune.

And when the heat
inside Neptune comes out,

you get updrafts,

and that drives the jet streams

and the whole thing
is a big weather machine.

NARRATOR: With no bulky land masses
to stop them,

Neptune's jet streams
keep going and going.

PORCO: It could be that the winds
on Neptune just grew over time.

They kind of developed over time
to be very rapid,

even though the energy that
started them off was very feeble.

NARRATOR: But what's underneath
the sheath of Neptune's ferocious winds?

Does the planet that takes its name
from the god of the ocean

live up to its reputation?

Can you really set sail
on a Neptunian sea?

HAMMEL: Just about everything
about Neptune and its system

relates to water in some way.

NARRATOR: One thing
most experts agree on

is that Neptune has
plenty of water.

However, exactly what form it takes
is less certain.

But it's something almost everyone
has an opinion on.

INGERSOLL: There's a lot of water
on Neptune,

but it's down deep,

and it's probably too hot
to be a liquid right now.

NARRATOR: Down here it's like
soaking in a planet-sized steam room.

Gas is squeezed into a liquid.

JOHNSON: Not an ocean,
but sort of a strange mixture

of atmosphere heavily laden
with denser and denser liquid materials

as the pressure got higher.

HAMMEL: If there were
an ocean on Neptune,

it would be very deep
inside the planet.

It would not be on the outer part
of the planet

where we could put a spacecraft
or a boat like this.

NARRATOR: On Earth, the combination
of heat and water

is essential for life to exist.

So what are the chances
of meeting any locals here?

FRAN BAGENAL: You've got some warmth,
you've got hydrocarbons,

you've got water.

You could well have
developed some life form.

Somehow | suspect it's not going to be
particularly sophisticated.

But who knows?

Maybe there are big stingrays
swimming around deep in the ocean.

NARRATOR: Not a fan of the deep?

Don't worry.

Like its icy neighbor,

there's plenty more to see and do
without getting your spacesuit wet!

PORCO: Those of us
who are interested in rings

got teased mercilessly as we were
on approach to Neptune

because it wasn't clear
Neptune had rings per se.

They were just impartial arcs
is what the mindset was,

that was our idea.

And then finally when we got there
we did find Neptune had diffuse rings,

complete rings, but also these
rather opaque ring arcs.

NARRATOR: Neptune's rings may not be
the prettiest in the Solar System,

but they're still worth
a snapshot or two.

HAMMEL: Neptune's rings
are clumpy.

There are sections that are very bright
and sections that are very thin.

SPILKER: These particles
are very dark.

There might be water ice
mixed with some organics,

or maybe just organic material.

They only reflect a few percent
of the sunlight that they receive,

so very, very dark.

Very different from Saturn's
bright, icy rings.

NARRATOR: It's thought
these gangly ring arcs

are kept in check by the gravity
of tiny satellites,

known as "shepherd moons."

PORCO: This was something
in fact | was personally involved in,

in trying to understand
how the arcs were there.

And we found that they were
being anchored by one of the moons,

the moons that in fact Voyager
had found in the ring region.

SPILKER: As a ring scientist
I'd be very interested

in collecting some
souvenir ring particles.

And so | would probably try and get
a space-worthy jet ski equivalent

and then go to explore
the rings of Neptune.

NARRATOR: Neptune's ring arcs are
one of a kind in the solar system.

But the real showstopper here
is Neptune's moon, Triton.

Suspended animation has long been
a favorite topic of science fiction.

Like the clients of this
cryogenic facility in Arizona,

the space traveler of the future
could well become a time traveler.

MARK VOLKER: The purpose is to hold them
in a state of suspended animation

until such time
as they can be reanimated.

NARRATOR: Inside these canisters
are the frozen remains of 88 people,

all hoping for a second shot at life.

The problem with cryogenic suspension
is that it's not very user-friendly.

You have to die first.

But for the space traveler of the future,
that could all change.

VOLKER: So you could put them
in a state of suspended animation,

put them on a spaceship,

and months or years later
wake them up at the destination

so they wouldn't have to be
alive and conscious

and eating and doing all the other things
that you have to do when you're alive.

NARRATOR: Already scientists are working
on ways to slow down metabolism.

CHENG CHI LEE: It's about two hours
after we have injected the AMP,

and the mice now are
in a deep hypothermic state.

NARRATOR: The mice,
who don't normally hibernate,

are injected with a nucleotide
that inhibits thermoregulation.

A state of hypothermia is then induced
by lowering their core temperatures.

After around two hours,
the rodents stir.

LEE: So what happens now
is the mice is now in an arousal state.

NARRATOR: They're a little sleepy at first,
but completely unharmed.

LEE: | hope that within ten years

we can run some of this in a human trial,
somewhere down the road.

NARRATOR: Could this really be
the future of space travel?

If we're to undertake the incredible
journeys to planets like Neptune,

suspended animation may be
the only practical solution.

But will a trip out here
really be worth the time and fuss?

Well, some planetary scientists think
it could be, if only to visit Triton.

PORCO: Well, | remember
the night we flew over Triton.

We stayed up all night

because | think the flyby
happened early in the morning.

And it was just so unusual.

PAPPALARDO: Oh, boy, Triton
is an extremely complex moon

that we understand only in part.

NARRATOR: The largest
of Neptune's 13 known moons,

Triton covered in a thin layer of ice...

its surface rippled and textured
with features seen nowhere else.

PAPPALARDO: Triton has pits
on part its surface

that's called the cantaloupe terrain

because looks a lot
like the surface of a cantaloupe.

BURATTI: The other interesting thing
about Triton is that it has a violent past.

It was almost certainly
captured by Neptune.

The reason we're certain
that it was captured

is that it is rotating,

it is going around Neptune
in the opposite direction.

NARRATOR: And hiding
in these fuzzy pixels

is Triton's biggest
party trick of all.

Voyagers' camera captures geysers
that shoot high into the air.

PORCO: It was found that there were jets coming
off the polar cap of Triton.

And these things were going
some 15 kilometers,

or 10 miles, into the air

and then taking a 90-degree turn
as they hit a prevailing jet

in this very, very thin atmosphere.

PAPPALARDO: We're not sure
if these plumes are powered

from the internal heat engine of Triton,

or are they actually powered
by the very weak and far away sun,

which might be causing
some local evaporation

to make these plumes.

NARRATOR: These are Triton's
ice volcanoes

that purge an inky cocktail
onto the gleaming surface.

HAMMEL: When we see black stuff
in the outer solar system,

we think organic material.

Organic does not mean
life or plants,

organic in our talk means carbon, carbon-bearing.

BURATTI: This is, these are
the building blocks of life.

So we think that that dark material
may be pre-biotic chemistry going on.

Not life itself,
but the precursor to life.

PORCO: So here we find,
even our last port of call,

Triton, you know,
cold, cold, cold body.

And yet there is
this activity going on.

NARRATOR: So you've finally made it
to the outer solar system,

following the epic journey
of Voyager 2.

After 12 years of traveling,
what do you do on a short stop

before turning around
and heading back home?

BURATTI: Well, if | were going
to the outer solar system, going to Uranus,

| think first of all I'd want to orbit
Uranus a couple of times

just to take in those rings.

Because | think that rings

are one of the most beautiful sights
in the solar system.

JOHNSON: I'd go picnicking on Triton,

and I'd make sure that | took
some really warm clothes with me

and some binoculars

because sitting on Triton

and looking at this beautiful
blue Neptune hanging up there

would be quite a trip, actually.

WOMAN: And then I'm sure | would sit
waiting for Old Faithful to go off,

however long that was going to take!

HAMMEL: By looking at the other planets
in our solar system,

we can learn
about planetary systems.

And | think that Uranus and Neptune
have stories to tell us

if we can only hear their stories.

NARRATOR: They are the ice giants
of the solar system:

two fathomless worlds, impossibly remote
and unimaginably hostile.

Uranus: the planet with the funny name,
but with hidden beauty.

And Neptune, a seemingly watery world
with a spouting moon.

It's unlikely humans will venture
out here anytime soon.

Until we do, who knows what other secrets await
discovery in the ice?

That's the beauty of traveling
the solar system;

it's full of surprises.