Original subtitles

NARRATOR: Got time for a 24-year vacation?

Then consider a journey to the most distant planets

of our Solar System.

CAROLYN PORCO: 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.

HEIDI HAMMEL: 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?

HEIDI HAMMEL: 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.

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're 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 bullseye.

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.

HEIDI 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.

HEIDI 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 text books 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: I pronounce it 'YOOR-a-nus'.

I think people are embarrassed about 'Your-ANUS'.

CAROLYN PORCO: 'YOOR-a-nus'. Yeah.

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

which is very likely closer to the original pronunciation of

the name of the god after who 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 the Third.

But the custom of naming planets from ancient mythology prevails,

and 'Planet George' is no more.

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 'sixties

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.

GARY FLANDRO: So I started drawing pictures of

the Solar System.

And in that process I notice that all of the outer planets

turned out to be about the same alignment relative to the Earth

in the late 'seventies.

So I saw that I 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.

ED 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.

VOYAGER FILM NARRATION: A complex package of experiments

called Voyager is designed to take the first thorough close-up

look of 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.

TORRENCE JOHNSON: The outer Solar System is called 'outer'

for a reason. It's a long way away.

CAROLYN 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: Onboard, there's even a gold record containing a

greeting from Earth, should the spacecraft encounter

any friendly aliens.

VOYAGER RECORDING: Hello from the children of Planet Earth.

ED STONE: We knew the Voyagers were going to be the first to

reach interstellar space.

So we thought 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 centre 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'.

CAROLYN 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?

Planning a vacation to Uranus?

Time to study up on what you're about to get into.

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 a minus 355 degrees Fahrenheit.

But the biggest, most obvious feature about Uranus

is its crazy tilt.

However, it wasn't always this way.

TORRENCE 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.

TORRENCE JOHNSON: Uranus' tilt actually results from some

rather complicated interactions with Saturn and Neptune

and Jupiter even.

All of these planets do have gravitational affects on one

another and the affects 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.

ED STONE: Well that's 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.

TORRENCE JOHNSON: Being there when the images are coming in

makes you feel like you are on the bridge of

the Starship Enterprise.

Because you really feel like you're there,

those are just your sensor screens and you are getting

reports back from these alien worlds that you are

taking a look at.

CANDY HANSEN: Who could ever have enough pictures

of Saturn's rings?

NARRATOR: So what do Voyager's cameras reveal of Uranus,

the lopsided planet?

TORRENCE 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 BURATTI: From the Earth it looked kind of bland.

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

HEIDI HAMMEL: The images of Uranus were

a little bit disappointing.

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

GARY FLANDRO: Not much going on at Uranus.

NARRATOR: These are the very 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.

JACK 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 get de-conditioning.

NARRATOR: From this control room in Germany,

a medical team scrutinizes the health of the European

astronauts onboard the International Space Station.

VOLKER DAMANN: The astronauts workout 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's ever been in space that long.

KEVIN FONG: Human missions to the outer planets are going to

take years, even more than decades.

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 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 percent 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.

KAREN PICKERING: We take waste water strains from a

variety of sources.

We take hygiene water from your showers, washing your hands,

brushing you 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 but it's distilled so it doesn't taste as good as your

water from the tap because there is 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.

So you've survived the decade-long journey to Uranus.

Hopefully, you haven't put on too many pounds from the

10,000-plus inflight meals. Time to start exploring.

From orbit, Uranus gives little away.

But plunge below its placid-looking clouds and you

encounter a world that's anything but.

HEIDI HAMMEL: So let's imagine I 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.

HEIDI 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 leftover from when the planet formed.

ED 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.

JACK 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.

HEIDI HAMMEL TO CAM: 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

4200 degrees Fahrenheit no life, or robot, will last long.

TORRENCE JOHNSON: There would be no chance of surviving

under those conditions.

A probe going into the atmosphere would eventually

evaporate and would 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.

HEIDI HAMMEL: If I were to take a tourist trip to the Uranus

system, I 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.

TORRENCE JOHNSON: And it is an interesting sort of jigsaw

puzzle moon.

It looks like it has been put together by a potter without

paying too much attention to his materials.

It has 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.

BOB 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.

BOB 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 a state of differentiation.

NARRATOR: The result: a part-finished lunar construction

zone, with some pretty impressive sites to visit.

TORRENCE 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.

BOB 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.

TORRENCE 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.

HEIDI 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.

BONNIE 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 very complex family of rings

that we believe are these 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 we call 'high phase

angles', equivalent if you have a dusty windshield and you drive

into the afternoon Sun, the dusty particles light up.

So too in the Uranus system.

I remember sitting there as that picture came down,

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.

KEVIN 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 an enclosed,

confined environment with almost no privacy.

Death is always going to be just a half-thickness away and you

have to start thinking about how to stop your crews going crazy.

ASTRONAUT: Oooh!

NARRATOR: The possibility of going crazy is something these

space travelers know all about.

ESA OFFICIAL: Congratulations to the explorers,

to the mission organisers and 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.

NARRATOR: 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.

OLIVER 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 I didn't even think it tasted too bad.

NARRATOR: 105 days eating baby food

is certainly an achievement.

But who's going to do that for 24 years?

Moving out from Uranus is its ice sister, Neptune,

another mysterious ball of frigid gas.

And out here, there's proof the Solar System still has a few

incredible tricks up its sleeve.

On the approach to Neptune, be prepared for a surprise.

Because at the end of the Solar System is a reminder of home: a

second blue planet.

CAROLYN 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 I 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.

HEIDI 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?

TORRENCE JOHNSON: As we were approaching Neptune,

and it was getting larger and larger on the TV screens in the

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.

ANDY INGERSOLL: Voyager saw several spots,

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

TORRENCE 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.

HEIDI 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.

HEIDI 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's 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.

ANDY INGERSOLL: What drives the weather?

There's two things.

One is the Sun, 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.

ANDY INGERSOLL: 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.

CAROLYN 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?

HEIDI HAMMEL: Just about everything about Neptune and its

system relates to water in some way.

NARRATOR: One thing most experts agree upon 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.

ANDY INGERSOLL: There's a lot of water on Neptune but it's down

deep and it is probably too hot to be a liquid right now.

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

room, where gas is squeezed into a liquid.

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

an atmosphere heavily laden with denser and denser liquid

materials as the pressure got higher.

HEIDI 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

essentials 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 I 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!

CAROLYN PORCO: Those of us who are interested in rings got

teased mercilessly as we were on approach to Neptune because it

wasn't clear if Neptune had rings per se.

They were just impartial arcs is what the mindset was,

that was our idea.

And finally when we got there we did find Neptune had defuse

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.

HEIDI HAMMEL: Neptune's rings are clumpy.

There are sections that are very bright and sections

that are very thin.

LINDA SPILKER: These particles are very dark.

There might be water ice mixed with some organics,

or 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'.

CAROLYN PORCO: This was something in fact I 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.

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

in collecting some souvenir ring particles.

And so I would 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 show-stopper here is Neptune's moon, Triton.

Just getting to Neptune means putting your life on hold for

24 years. That's a lot of inflight movies.

But what if you could literally put your life on ice?

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 that

they can be reanimated.

NARRATOR: Inside these canisters are the frozen remains of 88

people, all hoping at for a second shot of 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.

MARK 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, 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.

CHENG CHI 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.

CHENG CHI LEE: I 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.

CAROLYN PORCO: Well I remember the night we flew over Triton.

We stayed up all night because I think the flyby happened early

in the morning. And it was just so unusual.

BOB 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.

BOB PAPPALARDO: Triton has pits on part its surface that's

called 'The Cantaloupe Terrain', because looks a lot like the

surface of a cantaloupe.

BONNIE BURATTI: The other interesting thing about Triton

is that it has a violent past.

It was almost certainly captured by Neptune.

And the reason we are certain that it was captured is that it

was 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.

CAROLYN 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.

BOB 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.

HEIDI 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'.

BONNIE 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.

CAROLYN 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?

BONNIE BURATTI: Well if I were going to the outer Solar System,

going to Uranus, I think first of all I think I'd want to orbit

Uranus a couple of times just to take in those rings.

Because I think that rings are one of the most beautiful sights

in the Solar System.

TORRENCE JOHNSON: I would go picnicking on Triton and I'd

make sure that I 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.

CANDY HANSEN: And then I'm sure I would sit waiting for Old

Faithful to go off, however long that was going to take!

HEIDI HAMMEL: By looking at the outer planets in our Solar

System we can learn about planetary systems.

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

if we can only hear their stories.

NARRATOR: They're 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.

AtZLIT 2010.