Original subtitles

- [Voiceover] The fastest spacecraft ever

to leave the Earth.

A nine-year marathon crossing three billion miles

to see a mysterious world lurking in deep space.

- Is it alive, or is it completely frozen?

- [Voiceover] They have only one shot to get it right.

- So there'll be a little bit of tension in the air.

- [Voiceover] Through unknown peril.

- If New Horizons were to hit something as small

as a grain of rice, it would be game over.

- [Voiceover] History will be made.

And we are there.

- We've hit the motherlode of fascinating objects

in this particular mission.

- [Voiceover] Our destination is Pluto

and the Kuiper Belt beyond.

This Atlas V rocket is about to launch

a very special mission.

- [Voiceover] Three, two, one.

We have ignition and liftoff!

(rockets faintly blaring)

- [Voiceover] This is the New Horizons Spacecraft.

It's on a voyage to the last unexplored planet

in our Solar System:

Pluto.

But nearly two-thirds of its journey

is in a state of suspended animation.

All instruments not essential to navigation

and flight control are turned off.

This preserves the battery and reduces wear on equipment.

New Horizons has had 18 naps since its launch;

each ranging from 36 to 202 days long.

That's roughly two in-flight naps per year.

During each nap, the spacecraft sends a beacon tone

once a week to let its friends back on Earth

know that all's well.

But this is the last nap New Horizons will take

before it makes history.

- We really have never been to a planet like Pluto before.

It is the farthest foot fall that any humans

have ever made on another shore

to go and explore a small planet

three billion miles from Earth.

- It's an incredibly pristine body

in the sense that it's experienced relatively little

evolution over the four and a half billion years

that the Solar System has been in existence.

- [Voiceover] It is a geologic time capsule.

- Pluto happens to be a linchpin for understanding

the formation of our Solar System.

And some of the most important questions

that we can ask as 21st-Century planetary astronomers

have to do with how the Pluto System formed.

- [Voiceover] A clue might be found in Pluto's

oversized moon, Charon,

about the size of the state of Texas,

and roughly 10% the mass of Pluto itself.

Its sheer size suggests something about

the formation of Pluto, something terrifying and violent.

- The best models we have so far indicate that Charon

was formed in a titanic collision between Pluto

and another formerly-existent planet

that smashed into it billions of years ago

and spalled material into orbit

that coalesced to form Charon

and probably the other satellites as well.

- [Voiceover] Pluto marks the inner boundary

of a vast realm at the edge of our Solar System,

populated by chunks of ice and rock.

Some are as large as Pluto itself.

- So it's most probable that these icy planets,

like Pluto, are actually objects that formed

in the outer Solar System in great numbers;

most of which are gone today for one reason or another.

And the ones that we see are the relics

of what was formerly a much larger population.

- [Voiceover] New Horizons is mankind's first reconnaissance

of this outer region of our Solar System.

Pluto is the probe's first destination.

We are roughly four and a half months away.

- When we pass through the Pluto System

we're gonna be going very deep.

We're gonna get in closer than any of the satellites' orbit.

In fact, we're gonna pass about halfway

between where Charon orbits the innermost moon

and where Pluto is.

So we're gonna be way down among 'em

and taking great data the whole way.

- [Voiceover] New Horizons has a long to-do list,

but its goals are simple:

reveal the geology and landforms of Pluto and Charon,

map the surface composition,

and analyze the atmosphere and determine its escape rate.

- What kinds of geological features are on the surface?

Is it alive in terms of eruptions or tectonism,

or volcanism, or who knows what?

Or is it completely shut-down and frozen?

- [Voiceover] Ever since its discovery,

Pluto has been a place of mystery.

In 1929, a Kansas farm boy with a talent

for building homemade telescopes

starts a new job at the Lowell Observatory

near Flagstaff, Arizona.

That farm boy is Clyde Tombaugh,

and his task is to help locate a hypothetical planet

thought to exist beyond the orbit of Neptune.

He uses a machine called a blink comparator.

This lets a person compare images taken

on two different evenings.

Any object that has changed its location won't be a star,

it will be a planet.

In 1930, Tombaugh discovers Planet X.

And at the suggestion of an 11-year-old English girl,

Venetia Phair Burney,

Planet X is given a new name

in honor of the Roman god of the underworld, Pluto.

For the next 75 years,

Pluto is classified as the ninth planet.

Finally, in 2006, the New Horizons Mission is launched.

But a strange controversy begins

just six months after launch.

For many, it challenges our notion

of just what a planet actually is.

- Then this gets into the whole debate

of whether Pluto was a planet or not.

Pluto has been labeled a dwarf planet.

- [Voiceover] In 2006, Pluto is recategorized;

in the eyes of some, demoted.

A controversy is born.

- People ask me all the time about this controversy.

And the first thing that I tell them is,

is that it was really started by people

who are non-experts in the field.

- [Voiceover] Most people think astronomers

and planetary scientists are in the same line of work.

That's only true in the same sense

that a dentist and a brain surgeon are both doctors.

- Really, most astronomers don't know very much

about planets; they're not experts in it;

they don't go to the technical meetings.

And so the controversy was started by non-experts

in the field who happen to get the microphone.

- I think an object should be classified as a planet

based upon its intrinsic properties, not where it is.

Pluto was demoted from planethood because of where it is.

Its orbit intersects the orbit of Neptune.

And according to the IU definition,

a planet has to have swept out its orbit of debris.

And since it hasn't removed Neptune from its orbit,

it's not a planet.

But by that definition, if you took the Earth

and substituted the Earth for Pluto,

the Earth would not be a planet.

So that's telling you there's something wrong

with that definition.

- [Voiceover] What fuels the controversy even further

is the growing number of planet-sized bodies beyond Pluto;

at least one is bigger than Pluto.

Is it a planet too?

- We thought there were only nine;

but the final answer is probably closer to 900.

- [Voiceover] 900 planets in our Solar System.

But the debate about Pluto's status is a double-edged sword.

- In some respects, it's very helpful because

it attracts people's interest to astronomy

and to planetary science by wondering for themselves:

"Is Pluto a planet?" by their own criteria.

But the other side of that sword is it is very unfortunate

what happened in Prague in 2006

in that meeting of the astronomers

because they took a vote.

- The recommendation is that we consider Pluto

to be in a special class.

- [Voiceover] More than 2500 astronomers attend that

fateful meeting of the International Astronomical Union.

Yet, by the time the vote was taken, most had already left.

Less than 17% of the attendees were on hand to vote.

The problem is that the voting

should never have occurred in the first place.

- Those who are in favor of Resolution 6A,

which introduces this new category

of trans-neptunian objects with Pluto as a prototype.

- [Man] Votes don't work very well in science.

Because for many people, I think you convince them

that science is arbitrary.

- [Man] Those abstaining.

- [Man] That things like, let's say, evolution

or global climate change are arbitrary

and are decided by voting instead of by data.

- 237 in favor;

157 opposed.

- They should never have done it.

I think it sets science back.

It may have been the worst pedagogical moment

for science in recent memory and in past decades.

- [Voiceover] It's hard to imagine that the exploration

of a planet at the far end of our Solar System

can create such turmoil here on Earth.

New Horizons is already on its final approach.

A lot has changed since that fiery liftoff nine years ago.

Then, there is the discovery of Pluto's moonlets

and the realization that Pluto may be surrounded

by uncharted shoals.

In fact, Pluto is now dead ahead.

For the first time in history, Pluto is no longer a dot.

April ninth, onboard cameras captured

the first color image ever made

of the Pluto System by a spacecraft on approach.

Even at this distance, distinct differences can be seen.

Images taken by Lorri early to mid-April

from within 70 million miles

already reveal broad surface markings.

Lorri uses less power than a string of Christmas lights,

yet captures images in black and white.

Ralph is a color-imaging camera

that is able to capture images in light levels

a thousand times lower than on Earth,

allowing it to map the night side of Pluto.

Ralph can also see in the infrared,

the same as night-vision goggles.

This allows it to see heat sources.

And as a spectroscope, Ralph can discover

what the surface is made of.

But two more instruments will let us sniff around

and even get a taste.

PEPSSI will serve as our extended nose, sniffing the air.

SWAP looks at the way solar rays interact

with the atmosphere.

- About 10 weeks before we get to Pluto,

we can beat Hubble resolution,

and all the way in do better and better;

which helps us turn this encounter

from a simple weekend at Pluto

into a long study of the Pluto System.

- [Voiceover] Before New Horizons,

our best views came from Hubble images,

processed by Mark Buie.

As the spacecraft crosses nearly a million miles a day,

it gets closer, so the pictures of Pluto get clearer.

What's revealed are different light and dark regions

caused by variations in the planet's albedo.

- Albedo just means that's how reflective the surface is.

And there's some interesting patterns you see on here.

We see this big dark region here,

which we've known about for a long time.

- [Voiceover] These are regions where the ground

is covered with some carbon-rich material

that reflects very little light.

- We've got this region here, which turns out to be

the brightest region on the planet.

And we also know that's where the concentration

of carbon monoxide ice on the surface of Pluto is.

Because Pluto's brightness varies as it rotates,

we know that there's bright and dark patches on the surface.

- [Voiceover] Buie guided mission planners toward

a trajectory that coincides with the large bright patch.

This series of three images was made

by the Lorrie Telescope.

Every day, the images get a little sharper.

In the coming weeks, Lorrie's images

are going to improve dramatically.

History is being made.

New Horizons is 60 million kilometers from target

and closing.

All systems are working.

Sending a probe on a decade-long flight

some three billion miles away

is a crowning achievement of the Space Age.

- It began in the 1950s and through the advance

of technology we've been able to open up

the Solar System for the first time.

And as Carl Sagan said, "It's only true for one

"or two generations that you can be the first",

the first to Mars, the first to Venus,

the first to explore all these places

that had just been points of light in the sky,

and they become real worlds.

- [Voiceover] But no new planet has been visited

since Voyager 2 passed Neptune.

And yet, one world remains tucked away

in the pages of history.

As New Horizons closes in, a new discovery is made;

a discovery that points to sudden danger.

- When we discovered Pluto's small moons,

we realized that, just like every other object

in the Solar System, they would get struck

by still smaller debris as Pluto draws the system

through the Kuiper Belt.

And that the process of crater formation

on those small moons was a little different

than in some other situations where

we've gone exploring before.

Because the moons are so small,

they have almost no gravity.

And so, when you make a crater,

all the stuff that comes out of the hole

can't fall back on the moon;

it's moving too fast for the moon's gravity to retain it.

So that debris actually gets into orbit around Pluto,

where it's too small to see,

but where it poses a hazard to New Horizons,

or potential hazard at least.

Because the spacecraft is moving so fast,

to be hit by rock, or even a pebble,

or even something the size of a grain of long rice

could be very damaging.

So that was our concern.

- Here's this grain of rice.

This is actually bigger than you need

in order to wipe out the spacecraft.

Fact, if I baby...

OK, I just broke off most of it.

Can you still see that tiny little piece there?

This is still bigger than what it would take

to destroy the spacecraft.

OK.

That's a tiny little thing!

This is something that was gonna break a wire,

or break a lens, or wipe out the computer chip,

the CPU, something like that.

It's gonna be enough to end the mission.

- [Voiceover] A hazard team is formed.

Its goal is to search for any rubble in the flight path.

The danger lies in the unseen;

whether it's the size of a car, or even a grain of sand.

New Horizons is speeding in

at over 1.2 million kilometers per day.

Strike something at this speed, and it's game over.

One consequence could be that a damaged spacecraft

would keep collecting data, but is now unable

to relay it back to Earth;

or the spacecraft loses all of its power, and goes cold.

Despite the risk, the prospects for a safe passage

through the Pluto System look good.

- So the odds are very much in our favor.

And I don't wanna give you the impression

that we're sending it willy-nilly onto the beaches

of Normandy where the kill rates are very high.

There's almost no chance that it could be hurt,

but there's a small chance

because we are flying into the unknown.

- [Voiceover] Are there regions where the risks

of collision are greater than others

in and around the Pluto System?

- Charon is basically just this big vacuum cleaner

that's sucking up all this dust around its orbit.

That is probably one of the most dangerous

places you can go 'cause you get have dust

all over out there.

- [Voiceover] Because of Charon, the safest trajectory

is right through the heart of the Pluto System.

But the team remains vigilant.

- If we find something that screams out: "Danger, danger!",

then we can do what's called this antenna-to-ram maneuver

where we rotate the spacecraft to put the antenna

pointed in the direction of motion

for extra protection just to get it through that bad time.

Nobody wants to do that because

it does compromise the science we do.

But if that means the difference between

losing the mission and getting something,

that way we've got that in our back pocket.

- [Voiceover] For many, the next few days will be tense.

And then, it happened.

Contact with New Horizons is lost.

Mission controllers at the Applied Physics Lab

scramble to diagnose the problem.

Could New Horizons have struck something in space?

- [Voiceover] I think I was in the control center

between six and seven minutes after

I got the call in my office.

I'd be kidding ya if I didn't say that until

we reestablished contact, practically anything

could have been the problem.

- [Voiceover] Some 90 minutes pass.

Finally, a telemetry signal is detected;

but it is not from the main computer.

The team is uploading fly-by instructions

at the same time that the main computer is compressing data.

The primary computer overloads and shuts down.

The backup computer is running all systems,

and directs the spacecraft into safe mode.

The bad news is that some data is lost.

- [Voiceover] We lost 16 Lorrie imager observations,

four Ralph color observations.

About 30 observations all together over this period of time.

We can say that there's zero impact

to the highest-priority science.

- [Voiceover] It takes two days to bring

the main computer back online.

And now the team is back in action.

- New Horizons is doing great; it's right on course.

And all the scientific instruments are performing

completely as expected and we're getting great data.

- [Voiceover] After a journey of nine and a half years,

five days until flyby,

New Horizons is arriving at its destination.

- In fact, we're getting a lot of science now,

and we're discovering things every few hours.

The primary period, the really intensive exploration

is a nine-day flight plan that began

on July the seventh and ends on the 15th.

Throughout that period, the spacecraft is running

as hard a race as it possibly can to get

through all those observations.

- Status of the spacecraft right now is great.

It's operating and doing exactly what we want it to do.

- [Voiceover] A set of preprogrammed commands

will tell the spacecraft which instruments to use

and what maneuvers to make during the closest approach.

And the latest pictures are dazzling.

- Today, for the first time, I'm now looking

at this thing and it's not sorta like

a better version of my map,

but now a picture of a world.

To me, in my head, that transition just happened today.

Wow!

What's going on there?

Finally we're getting to rule out

certain ideas and theories.

It's not some big monstrous planetwide crater

like Sink of the Embryum Basin on the Moon.

That's not what's going on on Pluto;

but what is, I don't know, but it's an incredible ride

just watching this stuff come in day by day.

- [Voiceover] Another surprise is Charon's polar cap.

- We're seeing a feature on Charon already

which is a dark north-polar region.

There were no hints of this in the data

that I've taken over the past decades.

- Charon has a dark pole that was completely unexpected

and which we don't understand.

But in the coming days we're gonna be able to collect

compositional information about it

that may shed some clues on what it is.

But the details of things like whether

there's cantaloupe terrain on Pluto,

we'll only know after tomorrow's flyby.

So let me describe the encounter,

what's gonna be happening tomorrow, on the 14th.

Later this evening, we're gonna receive the last signals

from the spacecraft; and that's part of the flight plan.

Because after that point we are so close to Pluto

that we don't wanna spend any time

turning the antenna back to the Earth

to communicate with the Earth because whenever

the antenna's pointed at the Earth, the cameras

and spectrometers can't be pointed at Pluto and its moons.

So for the next roughly 24 hours,

the spacecraft will be completely on its own

and very busy because it's gonna conduct

hundreds of scientific observations

spread among the six targets in the System:

the planet and the five moons.

- [Voiceover] Now on final approach to Pluto,

the probe becomes autonomous,

continuously monitoring all of its navigation

and science subsystems, its temperature, and its voltages,

compressing and archiving data and tracking the planet.

Back on Earth, a huge crowd gathers at Mission Control,

anxiously awaiting the moment of closest approach,

when the spacecraft, after a journey of three billion miles,

will be only 7700 miles above Pluto's surface.

- [Crowd] Two, one!

- [Man] New Horizons and Pluto 2015!

(cheering)

- [Voiceover] New Horizons sweeps past the planet.

But it still has work to do.

- And then it will start to recede from Pluto

on the far side and continue to make scientific observations

throughout the day, throughout the evening.

It'll only take one break

to communicate back to the Earth for about 20 minutes

with, not data, but engineering telemetry to tell us

it made it, it's healthy, give us temperatures,

voltages, computer readings, things like that,

so that we know that we can feel relaxed about it.

That's gonna happen on the spacecraft at about

4:30 in the afternoon Eastern Time,

but the signal, traveling at the speed of light,

will take four and a half hours and it will reach

the ground around nine o'clock Eastern Time.

- I will breathe much easier tonight at 9:02 PM

because we've spent so much time studying the hazards,

and knowing that the spacecraft is sending us a signal

that says it's OK, that just means OK the fun begins now,

we don't have to worry about hazards anymore.

But we'll know that at nine o'clock.

It will be a great moment.

- Now, during that time when it's not talking to us,

we believe that the chance of the spacecraft

striking anything is very low, around one in 5,000,

maybe one in 10,000.

So we think it's very safe.

But, you know, that's our baby,

and during that time, you wouldn't be human

if you weren't a little bit interested

in that nine-o'clock transmission

to see that everything's gonna be alright.

So there'll be a little bit of tension in the air.

That's only normal.

- And on this mission you learned patience is a virtue.

- Especially on this one, right after nine and a half years.

What's a few more minutes to wait for something else

to happen? - [Man] Right, what's a couple

of minutes? (laughs)

- OK, I think we can go to Mission Operations right now.

So let's take a look inside.

- [Man] We're on the Deep Space Network.

- In lock on symbols.

- [Man] 'Cause that's the first step in getting data.

- OK, copy that.

We are in lock with telemetry with the spacecraft.

(cheering and clapping)

Go ahead, CNDH.

- [Man] CNDH reports nominal status.

Our SSR pointers are where we expect them to be;

which means we have recorded the expected amount of data.

- Copy that!

Looks like we have a good data record.

(applause)

We have a healthy spacecraft.

We've recorded data of the Pluto System.

And we're outbound for Pluto.

(applause)

- Yes!

- [Voiceover] The spacecraft is in working order.

The New Horizons team has gone where

no other human being has gone before.

- [Man] Thank you. - [Woman] Thank you.

- I would like to congratulate

the New Horizons Team of NASA on their pioneering

decade-long mission to explore the Pluto System

in the Kuiper Belt.

Billions of miles from Earth,

this little robotic spacecraft will show us

the first blips of mysterious Pluto

at the very edge of our Solar System.

- [Voiceover] Finally, the pictures begin to come in.

We now see the planet in exquisite detail.

Pluto becomes a known world.

- OK, so I'm not a geologist, but I am a rock climber

and I really like rocks.

And I ski, and I really like skiing.

So we're looking at this surface,

and I look at the snow, and I'm looking for rocks.

But actually, you look at those pictures,

and they are just mindboggling.

They're totally cool.

I mean we were all jumping up and down,

looking at them, wondering what's going on,

and asking the geologists: "What's happening here?

"What's happening there?", and it looked remarkably

like Mars; much better than Mars of course.

It's infinitely better than Mars.

(laughing)

It's kind of reddish; it's got impact craters;

it's got cracks.

- So first of all, we got high-resolution pictures of Pluto

that were just showed off here today,

the highest resolutions ever.

- [Voiceover] What about Buie's maps?

Did they guide New Horizons cameras

to the best regions for scientific work?

Buie's map predicted the heart-shaped region

now unofficially called Tombaugh Regio.

- It is no accident that we are looking

at that part of Pluto.

All of the ground-based data that we've taken up to now

and all of the Hubble data says, told us,

if you only can see one part of Pluto very very accurately,

which part would you wanna see?

And that's what we picked,

is this region centered right on Tombaugh Regio.

- [Voiceover] High-resolution images taken

by the Lorrie Camera reveal new landmarks.

Here, along the edge of the Sputnik Planum,

the autumn wind stirs a new chill

across this vast frozen plain.

Mysterious polygonal mounds rule the landscape,

until they reach the ramparts of ancient low-lying hills.

It is a region now known as Sputnik Planum.

Glaciers of nitrogen ice and slush

ooze along the walls of a timeworn crater

and spill into the Planum;

a process researchers are only just learning.

Along the equator lies a sudden

and inexplicable mountain range,

Norgay Montes,

a towering mountain of water ice some 11,000 feet tall,

dark and brooding over its icy domain.

The escarpments knife through the thin air,

defying all attempts at erosion.

- I think that's a case where

our own intuition about geologic processes is failing us.

This is so different that we need to learn about

a whole new style of planetary landscape management,

if you will, that other processes are working

in different ways, and we have to look

at all the clues that we're getting from the data.

We've only been looking at these pictures

for a few short hours, and we got a lot of surprises

that we're gonna have to work through.

- All I can say is it's wildly beautiful.

The thing that I keep coming back to is that

Pluto could have been boring.

At least from my standpoint, there are certain objects

in the Solar System that are just sort of

balls covered with craters, and Pluto is nothing like that,

and Charon is nothing like that.

We've hit the motherlode of fascinating objects

in this particular mission.

- [Voiceover] Pluto's moons surprise everyone.

- We have big news

from the first resolved image of Hydra,

Pluto's outermost moon, through the discovery

that Charon has been active.

- [Audience Member] Ooh!

(laughing)

- Thank you. Go ahead!

(applause)

- [Voiceover] The first set of images released

include this view of Pluto's outermost moon, Hydra.

The shape of Hydra is not clear.

Its bright white tonality is a mystery.

Things in space get dark with age;

and yet Hydra is very bright;

which forces many to speculate

Hydra is made of water ice.

Many predicted Charon would be a crater-covered world,

a fossil relic left over from the formation

of the Solar System.

- And what we're finding is that it's still a fossil relic

but it's been painted over every week

for the last four billion years.

Maybe not every week, but every few thousand years

we've got a new layer on top of it.

And so what we're learning is a whole lot

of very interesting geology.

We're gonna have to dig through that geology

not quite literally but using our data

to understand the composition

and the core properties and so on.

It is still a fossil relic and we will still learn

those properties of Pluto and Charon,

but it's gonna take a lot more work

than we had maybe anticipated.

- [Voiceover] Of particular interest is the black splotch

on Charon's north pole.

- The dark patch on the north pole of Charon

is definitely, it's a nice little Christmas present,

if you will, nice little surprise.

Nobody predicted that.

And we've already got a pretty nice explanation

that's been talked about.

It turns out that on the seasonal timescale,

one pole of Charon most of the time

is in intense long-term darkness.

And that dark pole cools down

to extremely cold temperatures.

- [Voiceover] The dark hues are a thin reside

of methane and ethane that survive the extreme cold.

There is an enormous chasm on the side of Charon,

and a sunken mountain nearly three kilometers high.

How did this happen?

It turns out that both Pluto and Charon

are not as dense and compacted as one might expect.

The material in the bowl surrounding the mountain

could have sagged from the weight of it.

- The surface of Pluto is very very complicated.

What we see from remote observations

is methane is the strongest signature

and nitrogen is the most by amount,

even though its signature is very weak,

and then we also see carbon monoxide.

- [Voiceover] Here we see a map generated from

the spectroscopic readings of LEISA.

Purple shows the distribution of methane across the surface.

The smooth Sputnik Planum appears to have

some of the highest concentrations of methane.

- We know from the bulk composition of Pluto,

from its density, that Pluto's got to have

a lot of water ice.

But spectroscopically we can't see that.

So that tells us perhaps from remote observations

that the water is completely hidden from view.

And that's certainly a big possibility.

- [Voiceover] 24 hours after passing through

the Pluto-Charon System, New Horizons is nearly

a million miles behind the planet.

The probe spins around, and captures

one of the most spectacular images of the mission:

the backlit atmosphere of Pluto.

- Then you've got Pluto with its extended atmosphere,

and it's losing stuff off the top

of the atmosphere all the time.

And there's some great models showing

just how much gas there would be in and around Charon.

- [Voiceover] Pluto has one of the most unusual atmospheres

in our Solar System.

It's a lot bigger than the rest of the planet,

and it's leaking into space.

As the spacecraft passes to the night side of Pluto,

Alice looks back into the sunlight

streaming through Pluto's atmosphere.

- Alice, which is an ultraviolet spectrometer,

has the capability of looking back through

Pluto's atmosphere as the spacecraft goes behind,

and look at ultraviolet light that's coming from the Sun

and being attenuated by the various gas species

in the atmosphere; and so that'll be a great way

of getting at the chemical compositions in the atmosphere.

- [Voiceover] Some speculate that the air was once

more dense than it is today.

- We know that Pluto's atmosphere has changed

dramatically in the last 30 years.

We've been measuring its atmospheric pressure from Earth

by watching stars go behind Pluto.

And the way that their light winks out

tells us the atmospheric pressure.

And it's doubled.

In fact, it's more than doubled from the '80s to today.

And that means that more material is in the atmosphere.

And it's either been injected,

for example from volcanoes or geysers,

or it's due to snows that have been vaporized

and become part of the atmosphere.

We don't know which; and it could be

a combination of both, in fact.

And when we get the data sets for composition,

and temperature, and topography, and geology,

we'll be able to put that whole story together

from those clues.

- [Voiceover] And yet, even as the planet slips

into the wake of history, data streams back to Earth.

- The data that's gonna come in from New Horizons

clearly is a lot about geology, but we'll get maps,

we'll be able to see where the light and dark patterns are,

and I'll be able to compare that to the maps

that I've done over the years.

But first I'm gonna savor the up-close pictures.

- [Voiceover] By week four after the flyby,

new images are downloaded.

Earth gets a second detailed look

at the strange geology of Pluto.

Here, we see new detail in the border realm

of the Sputnik Planum.

Strange blocks of water ice dominate

the center of this image.

The smallest objects are half a kilometer across.

Are these dunes of granulized nitrogen,

shifting in the winds of a cold Plutonian surraco?

Or are they frozen in place, like the sand dunes of Mars?

Here, we fly down to the surface of Pluto,

along the outer wall of a large crater.

The darker ground on the left is the oldest surface.

The older the ground, the more heavily cratered.

The yellow crater floor is not

as old as the darker surroundings.

The white ground is fresh nitrogen snow.

The moon, Charon, dominates the sky.

But does it really snow on Pluto?

Maybe not.

- We've even seen, even at the very low resolution

of our Earth-based and Hubble studies,

evidence over the last couple of decades

that Pluto's surface appearance is changing.

And so we're pretty sure it's due to

what we call volatile migration, or volatile transport,

which means snow is moving.

It's a fancy way of saying snow is moving.

The computer models show that

that's what should be happening.

The data, although sketchy from the Earth,

tells us that that's happening.

And now we're gonna go zooming right up on top of it

where we can really get the details.

- [Voiceover] How did the mountains form?

This image is some 75 miles across.

And we can see details down to 270 meters.

Lone mountains draped in streamers of red bunting

form an unexpected archipelago in a sea of frozen nitrogen.

The patterns resemble wind-whipped dunes.

- So here we have these great pictures

that were just released today

that show these topographic features,

these mountains that are huge by any measure.

And you can't make that out of nitrogen

or methane or carbon monoxide.

The only building block that you have in Pluto

that you can make these with is rock and ice.

The rock, we think, is sequestered way deep

in the core of Pluto,

much like the Earth has got this iron core.

But Pluto we think has a mantle

that's made out of water ice.

- [Voiceover] Because water ice is less dense

than nitrogen ice, we see here chunky hills of water ice

pulled outward by invisible slow-moving currents

in frozen seas of nitrogen, like icebergs.

The force driving this convection is unknown.

New data from LEISA shows exposed water ice

to be considerably more widespread across Pluto's surface

than was previously known.

This suggests that Pluto's icy bedrock is hidden

beneath a thick blanket of other ices,

such as methane, nitrogen, and carbon monoxide.

- That's a real mystery.

And I think that points to the fact

that we don't understand these ice worlds.

- [Voiceover] But nothing is quite as startling

as the colors seen in this composite portrait.

Blue, red, and infrared images recorded by Ralph

resolve details as small as eight tenths of a mile.

Image processing is used to coax more terrain

from the region unofficially called Tartarus Dorsa,

hidden in the twilight.

We behold something totally new.

Nothing like it exists anywhere else in our Solar System.

A phalanx of strange ridges bristling

along the edge of night.

This region more resembles the scales of a dragon

or the bark of a tree than landforms.

Are the ridges the result of tectonic forces

generated by internal heat?

Or are they the work of sublimation

due to the light of a very remote Sun?

- We're gonna have to go back and understand why that is

that these rocky and icy worlds

stay wet longer than we ever imagined.

It's hidden deep beneath, but there's definitely

something strange going on there.

- [Voiceover] Are these wadis are record

of ancient flash floods?

Could these crater floors be covered by a fresh snow?

An early sign of the onset of a dark Plutonian winter.

- Pluto is far more active and diverse

than even my imagination said it was gonna be.

That's OK, 'cause every time we've gone to a new place,

we always find our imaginations are never up to the task.

- [Voiceover] Some seven weeks after the Pluto encounter,

New Horizons will begin to relay tens of gigabits

of stored data back to Earth.

As the distance continues to grow,

the downlink will diminish,

with speeds falling from 2,000 bits per second

to about 700 bits per second.

- And even though we're using the very largest

antennas on the ground that we have, the 70-meter,

it will take 16 months for us to get

that data back to Earth.

- [Voiceover] By 2017, New Horizons will be deep

in a realm of far-flung chunks of ice.

But what is this new region?

Science now divides our Solar System into three zones.

The innermost planets, Mercury, Venus, Earth, and Mars,

are small, rocky, and close to the Sun.

This is the first zone.

The second zone is the domain of gas giants,

Jupiter and Saturn, Uranus and Neptune.

Tiny Pluto marks the outer edge.

Yet, astronomer Gerard Kuiper predicts the existence

of a belt of icy bodies that lie beyond Neptune,

girdling the entire Solar System,

a vast flattened plain of icy bodies

now called the Kuiper Belt.

New Horizons is now making its way toward its next target:

the Kuiper Belt object designated as PT-1,

a potato-shaped chunk 45 kilometers across,

likely similar to the Plutonian moons Hydra or Styx.

The rendezvous with PT-1 is set for January 2019.

By then, New Horizons will be another

billion miles from Pluto.

- Another thing that we don't know about

is a small end of the size population in the Kuiper Belt.

And broken up little bits of Kuiper Belt objects

are what come in to make comets,

which are tiny tiny little fragments of Kuiper Belt objects

a kilometer across instead of the 100 kilometer across.

- [Voiceover] Understanding the formation and evolution

of our Solar System has come a long way

since the discovery of the Kuiper Belt.

- We know there was a period of time in the first

billion years that this was a dangerous place to be,

anywhere in the Solar System.

One epoch in the past of our Solar System,

the giant planets were all moving around.

They were actually plowing into the original Kuiper Belt.

We're only seeing the remnants of the Kuiper Belt right now.

And Jupiter, Saturn, Uranus, and Neptune

probably plowed into that

and just scattered them all over the place.

- [Voiceover] These scattered bodies caused numerous

collisions; most small; some large.

And in the case of Pluto and one other planet

in our Solar System, there was a collision big enough

to smash the entire world.

That other planet is Earth.

And from the scattered debris, our moon was formed.

Astronomers call this period The Late Heavy Bombardment.

The abundant craters across the face of the moon

are a testament to the violence of this epoch.

- [Man] We think that these large-scale collisions

between planets early in the Formation Era of Solar Systems

are common; and in computer models,

we see that happens a lot.

- [Man] Here we've got clues out in the Kuiper Belt

that indicate that's what happened.

- And the fact that we have more than one example

in our own Solar System is evidence that adds to

what the computer models are telling us to say

those models are probably right,

it probably actually does happen a lot.

So systems like Pluto-Charon

or like the Earth-Moon may be common throughout the Galaxy.

That's one of the exciting things about going

to Pluto's System is that we're looking at something that,

although it's far from our Earth

and far from our common experience,

may actually be important in planetary science

in other solar systems as well.

- [Voiceover] With so much success exploring Pluto

and the Kuiper Belt, New Horizons is giving us

an account of our own origins.

And just what kind of gumption does it take

to send a probe to Pluto, the Kuiper Belt,

and new mysteries beyond?

- It's the curiosity in me.

It's uncovering the mysteries, things that we don't know.

It's that continuing revelation.

- Each time you see a planet for the first time ever,

it's really amazing.

There's just so many surprises

and you learn so much more because it was

a distant point of light and now suddenly it's a world

that you have maps of and you can count the craters

and you can see what's going on on the surface.

- [Voiceover] Only one nation has, in the past 50 years,

opened the entire Solar System,

and is now probing the Kuiper Belt.

- In that 50 years the United States swept across

the entirety of our Solar System

and was first to every planet in the Solar System.

And as a result of that, we not only make huge discoveries

about nature and about the formation of our place

in the universe, our home Solar System,

but we also made a great impression, I think,

across the world for what our society and our country does.

- [Voiceover] Yet, for all the skeptics and cynics,

New Horizons is the reply.

- People often ask if we're as good as we used to be,

if we're on our game,

if America is the same America

that did things like Apollo,

that New Horizons is an example, I think,

of what we do best: making history,

developing new knowledge, and doing it for all mankind.

- [Voiceover] Each week, new knowledge will be gained,

until all of the data is finished downloading in early 2017.

Some six months since the encounter,

the latest pictures reveal a world alive

with bizarre forms of geology not known on Earth.

Here, scientists think is one of the largest

cryovolcanoes in our Solar System.

The Ralph Camera reveals mysterious red splotches

around the volcano.

The region must be geologically active,

because only one lone impact crater can be seen,

their origin and nature unknown.

The New Horizons project is a juggernaut of determination,

patience, and planning;

a fusion of engineering and science;

and it is the ultimate expression of our curiosity,

reaching into the high plains of the Kuiper Belt

and into deep space beyond.