This video was made by stitching together thousands of snapshots,
taken in the neighborhood of Saturn, by one remarkable spacecraft:
It’s 22 feet long,
and swaddled in a shiny thermal blanket
to keep its insides cozy in the temperature extremes of space.
It was named after 17th century astronomer
Back in his day, Saturn was the most distant planet humans knew about,
and peering through his telescope across a billion miles of space,
Giovanni could just barely make out a tiny gap in the rings.
Cassini the spacecraft was designed
to travel that billion miles and take a much closer look.
In 1997 NASA and the European Space Agency
shot it out into the solar system.
It swung past Venus twice, picking up speed,
then back by Earth and on past Jupiter.
Until finally, in 2004, it reached orbit
around Saturn and started taking lots of pictures.
Pictures of some of the strangest sights in the solar system.
On Saturn's north pole,
there's an ever present hexagonal storm
that’s larger than the planet Earth.
The vortex at its center could swallow up the Midwest.
As the seasons have changed on Saturn,
the hexagon’s color has shifted from blue to gold.
Titan is Saturn’s largest moon.
It’s covered by a thick atmosphere of nitrogen,
but Cassini was able to peer through that yellow haze with infrared sensors and radar.
There were dunes, clouds, rivers.
Here, the sun glints off the surface of something —
it’s an enormous lake.
But that’s not water.
It's liquid hydrocarbons — ethane and methane.
To get some close-ups of Titan’s surface,
Cassini dropped down a little robot.
Enceladus is a little frozen moon.
The sections of its icy surface are always shifting around, and scientists say there’s
probably an ocean of liquid water hiding beneath them.
That’s exciting because where there's water, there could be life.
Along these grooves are huge geysers.
They’re called “cryovolcanoes" because they shoot icy water and hydrogen into space.
That spray creates this faint outer ring around Saturn.
Saturn’s central rings are mostly made of ice and dust.
They’re nearly a billion feet across from edge to edge, but in most places they’re
only about 100 feet thick.
When the sun lines up perfectly with the rings' plane, you can see vertical structures cast
long, jagged shadows.
The gravity of passing moons makes the rings ripple,
and in at least one place, it looks
like dust particles in the ring are clumping together to form a new moon.
Our old friend Giovanni Cassini used to wonder about the two tones of the moon Iapetus.
Cassini the spacecraft discovered that the shiny side is glazed with ice, while the dark
side is covered in dust — picked up like bugs on a windshield as Iapetus
wheels around Saturn.
That dark dust absorbs heat and keeps new ice from forming.
And there’s another weird thing about this moon.
You can see this huge mountain range near the equator.
Its peaks are taller than Everest.
Scientists think Iapetus once had its own little ring system that one day collapsed
inward and fused with the moon’s surface.
In 13 years and 293 orbits around Saturn, Cassini has snapped 400,000 photos,
compiled 600 gigabytes of data and discovered at least seven new moons.
The mission was supposed to end in 2008 -- but Cassini just kept on trucking.
Now, it’s finally starting to run out of fuel.
Scientists are worried that when it loses power, it could crash into a pristine moon, contaminating
a place where we might someday search for life.
So they’ve decided to smash Cassini into Saturn.
Cassini’s silicon and aluminum body will disintegrate in a fireball, and finally Cassini’s
fuel — its plutonium heart — will melt away.
Cassini will be gone, but we’ll still have all the postcards it sent back home.