Original subtitles

- [Narrator] The amazing Cassini spacecraft

and its sibling lander Huygens have now concluded

their scientific studies, bringing back years of data

to be combed through by scientists,

plotting their next journey to Saturn and space.

Now it's time for other planets

and other spacecraft to shine.

Juno, piercing the cloak of Jupiter,

and her distant relative, New Horizons at the edge

of the Solar System.

(dramatic music)

(catchy piano music)

After 20 years, the Cassini project finally comes to an end

in dramatic style.

But with one door closing, another opens.

Now, the enviable task of having to unravel the data

Saturn has just laid bare begins.

And, we have literally just scratched the surface.

- I think Cassini has left us with humankind's presence

at another planet for 13 years,

seeing things that we have never imagined seeing.

And at the same time, sharing that with the entire world

and opening up vistas for the next sets of missions.

- [Narrator] One of these is facing scientists

when looking at exploring the new frontier

is leaving it in a better state than they found it.

So, eliminating the problems of space junk,

or the introduction of alien microbes is paramount

in their decision making.

- And it also helps us satisfy,

a planetary protection requirement.

We're protecting the tiny moon, Enceladus

as well as Titan.

Both of those have global oceans underneath their icy crusts

and just in case there might be life in those oceans,

we don't want Cassini to crash into one of those moons

once we're out of fuel.

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- [Narrator] While the main focus of the Cassini mission

was to delve into the mysteries of Saturn and its rings,

the moons of Saturn proved most science-worthy.

And Saturn has many moons, in fact 62 with confirmed orbits.

Several are only 50 kilometers in diameter,

the largest being Titan which is bigger than Mercury.

The Huygens module that traveled aboard Cassini

also became the first probe to land on a moon

other than our own and transmit data back to Earth.

- The temperature at the surface of Titan

is about - 180 degrees, so it's very cold.

The landscapes of Titan look a lot like those

we have on Earth.

We have rivers, lakes, seas, almost oceans of methane.

It rains, it rains methane or a mix of ethane and methane,

so there are lots of meteorological phenomena

with geophysical phenomena on Titan that makes you think

of what happens on Earth.

But the ingredients are quite different.

- [Narrator] But it is Saturn's sixth largest moon

that excited many scientists, as it is virtually covered

by clean ice, and ejected plumes of water into space.

- My favorite moon is Enceladus.

And the reason I'm partial to Enceladus is it's

the moon that my team discovered a water vapor plume at.

But not only is there liquid water underneath the surface,

but there's organic material, there's a heat source.

When people get excited about the potential for life

elsewhere in the Solar System,

there are four things that you need.

You need a heat source, you need liquid water,

you need organic material, and you need those three things

to be stable over some period of time

so that life could potentially form.

At Enceladus, we've got three, we're not sure

about the stability over time yet.

And so based on the Cassini observations we made

back in May 2005, we've had lots and lots

more flybys of Enceladus.

Now we understand it much better.

We understand what organic material is there.

One of the instruments, the neutral mass spectrometer

in a very close flyby through the plume found some ammonia

in the plume.

- First of all, we see moons.

Then, we start finding out from the gravity measurements

and the imaging that there's an ocean,

and that it's global.

And then there was some measurements

by the cosmic dust analyzer that suggested

there was hot water being circulated through the rock,

the silicon dioxide nanoparticles.

This is just the final step that shows

that there's molecular hydrogen being produced

by these same hydrothermal processes,

and that molecular hydrogen has the chemical energy

to support microbial systems in the interior ocean.

- It's really the longevity of the Cassini mission

that has allowed us to put together the pieces

of the puzzle to really understand a moon like Enceladus.

And even this late in the mission, we continue

to look at our data to better understand this ocean world.

- [Narrator] Collating data is one thing,

but interpreting and providing a vision

for future missions is another.

This is an area for which the Cassini project

came up trounced, because it not only brought together

free agencies, it provided the ground for future scientists

to develop skills that will provide the basis

for new projects.

- The number of Ph.Ds we've put through the system,

they are going to be the educators of the next generations.

We've put out 3,000-plus peer reviewed papers.

Hundreds of Ph.Ds, thousands of peer-reviewed papers,

the scientific legacy is huge.

The engineering legacy of using every ounce

of engineering capability to exploit a system,

I think is, again, will be built upon.

And I can't ignore the international cooperation.

This, we had 19 nations contributing hardware

to this mission.

We've got over 26 nations now contributing scientifically.

And despite whatever else is going on,

this really has been an amazing collaboration

across the world.

- [Narrator] The mighty Jupiter is the current target

under the microscope with the Juno mission in full swing.

The story of our Solar System is linked to Jupiter

as it is believed that it was the first planet formed.

So if we can understand how, we can begin to unravel

the origins of our Solar System,

and thus, how the Earth came about.

Juno must work in a very harsh environment

to tease out the answers from the gas giant.

- When you go to a place as hazardous as Jupiter,

we put a lot of time through the whole development process

in trying to design a spacecraft% that will operate

in the high radiation fields, magnetic environment,

spacecraft charging environment,

everything that you deal with with Jupiter.

And I have to say, the spacecraft

has been performing admirably.

- [Narrator] Jupiter's radiation belts pose

one of the biggest problems faced by Juno's scientists.

They exist within the enormous magnetic field

that surrounds Jupiter.

With its magnetosphere trapping of accelerating particles,

it produces intense belts of radiation

similar to Earth's Van Allen Belts,

but thousands of times stronger.

- Juno just flew by Jupiter for the first time

with all the science instruments on and it was spectacular.

The spacecraft performed flawlessly.

The instruments all worked exactly as planned,

and the data is amazing.

We're looking deep into Jupiter,

we're learning about the secrets that it's holding,

but we're also getting a lot of surprises about the aurora,

about the atmosphere, how it works.

I mean, it's just incredible.

- [Narrator] The flybys which followed showed

that the massive amounts of energy swirling

over Jupiter's polar regions were creating

the giant planet's powerful auroras,

but not in ways the researchers expected.

What puzzled the researchers was the fact that despite

the magnitude of these potentials at Jupiter,

they are observed only sometimes,

and are not the source of the most intense auroras

as they are on Earth.

- Juno had its camera, Juno came on.

During the flyby we got the first pictures

of Jupiter's poles, the north and south pole.

They were amazing, a lot of surprises.

It didn't look like we thought, doesn't look much

like Saturn's pole.

Jupiter's poles are covered in these cyclones,

like anticyclone storms, some of them half the size

of the Earth or bigger.

And we're puzzled as to how they could be formed

and stable in that configuration.

And the north pole doesn't look like the south pole.

And so we're questioning, the scientists are really

questioning whether this is a dynamic system,

and are we seeing just one stage,

and over the next year we're gonna watch it disappear?

Or is this a stable configuration,

and that these storms are circulating around each other?

- [Narrator] While the polar activity appears unique

to our Solar System, the engineers are looking

below its shell for answers.

- The new science results from Juno really are our

first look, close-up, at how Jupiter works.

And so for the first time, we're looking inside of Jupiter

into the interior, and what we're seeing

is that it doesn't work at all like we had predicted.

Almost every model that has the interior motion,

how the magnetic field, the gravity field,

how the deep atmosphere works, it's all different.

- [Narrator] Like most scientific undertakings,

they result in more questions being asked than answered.

- So Juno's original objectives really were

to understand how Jupiter formed.

And that would help us understand how planets

in general form, and how the whole Solar System was made.

What we're finding is that actually we didn't understand

giant planet dynamics very well,

the whole atmosphere or the interior structure.

- What we've seen so far is exciting, no question about that

but it's like a puzzle.

And we're putting the pieces of the puzzle together,

and it's exciting but we don't have the whole picture yet.

- [Narrator] And one of those puzzles

is the so-called Great Red Spot.

And while its presence in a turbulent gaseous planet

is not unusual, the scale is.

The red spot covers an area twice as large as Earth.

- [Scott] And we're gonna go right over the Great Red Spot,

and that's really gonna be the first time

that we get a close look at that and to see what it's like

underneath the top surface layer.

I mean, how deep are the roots of that.

That's a 300 year old storm.

A lot of scientists believe that the roots

must be very deep.

When we go over with our microwave radiometer,

we're gonna see, is it the same as the zones and belts,

or is it very different, and nobody really knows.

(grandiose music)

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- [Narrator] But it's not just Jupiter's poles

that hold the greatest interest for the Juno investigators.

They are also intrigued by the weather pattern

that is unique to this planet yet familiar in other ways.

Studying the atmospheric dynamics helps understand

other planets' atmospheres.

- So when we look at Jupiter, we see a lot of structure

that looks very similar to the Earth.

We can see storms, we see cyclones, we see anticyclones.

And these sort of storms and weather systems

that we see on Earth are very similar

and are happening on Jupiter.

Fluid mechanics is hopefully the same everywhere

in the universe.

But Jupiter and Earth are very different.

Jupiter's much bigger and rotates a lot faster.

They're made of different material

and Jupiter's much further away from the Sun

than the Earth is.

The quasi biennial oscillation or the QBO on Earth

is an equatorial phenomenon in the stratosphere

where the winds are changing direction

approximately every two years.

Depending on which phase the QBO is in, eastward or westward

the temperature signal corresponds to that,

so it's warmer in the eastwards phase,

and cooler in the westward phase.

It's been shown that it could actually be a barrier

to transport of aerosols across the equator.

And has been linked to the frequency in the formation

of hurricanes in the Atlantic and the Pacific Ocean.

The long term scales on Earth's climate is something

that we're very interested in and how that applies

to other planets' atmospheres is really why

we're studying Earth and Jupiter.

The quasi quadrennial oscillation in Jupiter's stratosphere

is the temperature signal that we see in the equator.

We see the temperature get warmer and cooler

approximately every four Earth years.

We used a general circulation model where we focused

on simulating the effects of small-scale waves

produced from convection in Jupiter's equatorial region

to simulate the QQL.

The waves propagate outwards from the clouds

and force the winds in the stratosphere to change direction

going from eastward to westward approximately

every four years.

Our model is able to reproduce the behavior of the QQL,

but was also able to reproduce temperatures

from the observations.

And both of those together give us a lot of confidence

that our model is very accurate in what's driving the QQL.

The outer planet serve as a laboratory

for understanding atmospheric physics

under very different conditions

that are present on the Earth.

Understanding how their atmospheres change and evolve

and their climates, can give us insight

into any planetary atmosphere.

- [Narrator] Juno has studied the planet

with a suite of tools, revealing much

that was previously hidden to the human eye.

- We have an infrared instrument on Juno called JIRAM,

and it was designed, and built, and delivered

by the Italian Space Agency.

And this instrument makes thermal maps of Jupiter,

so the images are showing you what's warm, hot, cold

on Jupiter, and one of the things you can see right away

is the center of some of these hurricane-like storms

are cooler than the surrounding area.

And sometimes you go over a warm spot.

And we went over one that was very small

but seems hotter than those surrounding area,

and that's very similar to what the Galileo probe went into

back in 1995.

- The Juno mission is unique, because it's the first time

that we've ever gone in a polar orbit,

which goes from pole to pole over the north pole

through periapsis, and under the south pole.

All the other missions we've done,

and all the observations we've made from Earth

were made from the equator.

And you don't see the poles very well

if you're sitting on the equator.

This is the first time we get the first, clear unobstructed

view of what the aurora looks like

and what the polar phenomena looks like.

And at the same time, we're flying through

the magnetosphere right above the aurora

so we can sample, in situ, the charged particles

that are precipitating down magnetic field lines,

the guys that are exciting the emissions that we see.

(dark music)

- [Narrator] Juno, like its sister Cassini,

has a used by date when the craft runs out

of maneuvering fuel.

This may occur during its 12th orbit

at the end of its prime and mission.

However, now some mean to extend the mission

if there are sufficient reserves.

In that case, the de-orbit would occur later

on the 34th orbit as part

of the planetary protection policy of NASA.

Its fact-finding mission is leading the way

for the one to come, the Europa Clipper,

a mission in the design phase to look closely at Europa,

the moon with a hidden ocean,

and the possible location for life to evolve beyond Earth.

(dramatic music)

(suspenseful music)

The blue haze of Pluto's atmosphere, possibly

a hydrocarbon smog, seen from 200,000 kilometers away

by NASA's departing New Horizons spacecraft.

A few years ago, the dwarf planet Pluto

and its five known moons were just small dots

in the outer reaches of our Solar System.

- One of the important things you should understand

about Pluto is the real scale of it compared

to the rest of the Solar System.

So we come here to the beach to really convey

that scale and distance.

So, if I draw the Sun as a 30 centimeter circle,

then we'd have to walk about 35 steps this way

in order to draw the Earth in the same type of scale.

So we're walking the equivalent of 150 million kilometers,

which we call one astronomical unit.

Normally, Pluto orbits at about 40 astronomical units

from the Sun, but it's actually quite an elliptical orbit

so it changes between about 30 and 50 astronomical units.

But, back to the Earth.

So the Sun is over there at 30 centimeters,

which means that the Earth should be about here,

about three millimeters, something like this.

If we were to draw Pluto on the same scale,

it should be 0.3 millimeters,

and it should be one kilometer down the beach,

so I'm going to draw it.

Now obviously, I can't draw something that's 0.3 millimeters

so I have to draw Pluto a bit bigger.

If this is Pluto, then its largest moon is Charon,

which is about half its size.

But Pluto has four other moons, Styx, Nyx,

Kerberos and Hydra.

So there's a lot going on around the Pluto system.

It's not just a cold, dead, icy rock.

(upbeat music)

- [Narrator] The spacecraft spent 16 months sending its data

back to Earth.

And scientists and non-scientists alike have been enthralled

by what it has revealed.

- If you go in closer to the surface,

you can see this type of really diverse terrain.

So you have a very bright region, these are flat plains,

not entirely sure how they formed yet,

but there's a couple of leading theories.

There's a huge range of mountains.

There's all kinds of different aged surfaces,

some of them have lots of craters,

some of them have very few which means they're younger.

If you look at a lot of detail at some

of the mountainous regions, you can see that

they are a few kilometers high but made of water-ice,

I mean, on Pluto it's so cold that water-ice

is the hardest thing, it's more like rock.

And so, the stuff that forms the softer material

is actually nitrogen ice.

- [Narrator] Water-ice on Earth is close to zero degrees,

but on Pluto, it's minus 230 degrees Celsius.

And as a glacier of nitrogen-ice, called Sputnik Planitia,

thought to be under a million years old.

This is young by planetary standards.

And no one knows yet how it formed or is renewed.

- One of the really fascinating things

is some of the surface coloration you can see

in these images actually shows

that there are these compounds called tholins

which are a combination of elements,

but they're related to pre-biotic molecules.

So they're kind of relevant to pre-biotic chemistry.

And I think the fact that they have been able

to form on planetary surfaces very far out

in the Solar System at very cold temperatures

really has implications for a lot of places.

I mean, if you can imagine for star systems outside our own

where the star may be dim and the planets are quite faraway,

it's interesting to know that there are molecules

that could be involved in supplying biotic material

to processes that may one day lead to life

or be involved in life or something like that.

They're actually forming way out in the Solar System

where no one really expected.

- [Narrator] Pluto is unlike anything seen before.

But the six gigabytes of New Horizons images

and scientific measurements are giving scientists

mysteries to unravel for years to come.

In the meantime, asleep for the moment,

the probe travels deeper into the unknown

soon to awaken at its next destination.

(ominous music)