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Orbiting the magnificent
ringed planet, Saturn,

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are a series of
extraordinary moons.

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The closer that we look,

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the more that we see its moons
are like worlds of their own --

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so dynamic,
so Earth-like.

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Almost a billion miles
from the Sun,

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these icy worlds could be
home for Life 2.0.

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The moons of Saturn
offer possibly the best

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chance of finding
extraterrestrial life

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in our solar system.

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With each new mission,
we get closer

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to unraveling the mysteries of
Saturn's moons.

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October 2019.

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Astronomers discover
20 new moons

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orbiting the gas giant,
Saturn.

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These tiny,
three-mile-wide objects

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bring the ringed planet's
moon count to over 80,

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the most of any planet
in our solar system.

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the most of any planet
in our solar system.

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You hate to play favorites,
but I'm gonna say it --

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Saturn is my favorite
planetary system.

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It is unbelievably beautiful,
with this incredible system of

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rings and moons,

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and there's a lot of mystery
kind of all bound up in there.

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The Voyager spacecraft
gave us our

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first close look at Saturn
and its rings.

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Two decades later,
Cassini got us even closer

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Two decades later,
Cassini got us even closer

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to many of Saturn's moons.

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There's Prometheus, Pandora,
and Atlas.

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Its largest moon, Titan,
is a moon that's shrouded

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in mystery.

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There's Mimas,
that's fairly small,

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and then Tethys and Dione
are a bit larger.

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There are a pair of moons --
Janus and Epimetheus --

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that were perhaps
one moon in the past.

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Iapetus, half of it's
bright white.

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The other half of it is
sort of as

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dark as coal,
sort of yin and yang.

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Each of
the moons of Saturn

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had remarkable
stories to tell.

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In 2005,
Cassini discovered that

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one moon's story was
particularly exciting.

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Yeah, Enceladus.

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Enceladus is one of Saturn's
wee little moons.

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It's about 300 miles across --
for scale,

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It's about 300 miles across --
for scale,

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it's roughly the size
of Colorado.

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The spacecraft's
cameras spot plumes of

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water vapor shooting
out from Enceladus

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at 800 miles an hour.

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Three times as powerful than

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all the hot springs
in Yellowstone.

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The discovery of
geysers gushing out of tiny,

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little Enceladus that should
have been cold and dead,

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little Enceladus that should
have been cold and dead,

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completely changed our view of
what that moon exactly was.

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It's alive.
That moon is alive.

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I'd like to be standing there
on the surface of Enceladus to

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see with the --
this water vapor

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and ice crystals booming
out of the surface

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at supersonic speeds.

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Cassini's sensors
probe deep beneath

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the frozen surface
of Enceladus,

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the frozen surface
of Enceladus,

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detecting hints
of a rocky core

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and something else
even more remarkable.

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Underneath that
thick layer of ice,

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there is liquid
water ocean.

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The measurements
suggest his is a huge part of

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Enceladus's interior volume,

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about six miles deep,
because it was making Enceladus

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wobble in its orbit.

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Imagine putting liquid inside
a ball and rolling it.

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You see the natural wobble of

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You see the natural wobble of

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the ball as the liquid
sloshes around.

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Giant liquid oceans
on an alien world,

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opening up exciting
new possibilities.

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Where you find water,
you could possibly find life.

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If you had asked me 20 years
ago where there might be life

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in the solar system
besides Earth,

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I think Saturn's moons would
have been the last place

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I would have picked.

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But against all odds,
it's looking like this tiny icy

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But against all odds,
it's looking like this tiny icy

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moon orbiting Saturn

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nearly a billion miles from
the Sun may be one of

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the best places
to look for life.

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July 2021.

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A new study reexamines
Cassini's plume data

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and finds huge quantities
of methane.

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This large amount can't be

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explained by just
geochemical processes.

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The methane might be from
primordial organic matter

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breaking down in
Enceladus's oceans,

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or even processes
we've never seen before.

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But it could be that

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living microorganisms helped
generate the methane,

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just like they do on Earth.

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Enceladus might actually look
a lot like early Earth in its

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Enceladus might actually look
a lot like early Earth in its

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deepest oceans,
when life was first arising,

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because we know that there are
some chemical pathways that are

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likely occurring on Enceladus
that happened on Earth.

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These chemical pathways
start with

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hot, hydrothermal vents
on Earth's

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cold sea floor, releasing
important life-giving chemicals

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into the oceans.

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Having hydrothermal vents
are a real

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boon to the evolution of life.

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These are cracks in
the Earth's crust, where

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These are cracks in
the Earth's crust, where

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hot material can then spew out
into the ocean.

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And that's the energy

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that life needs
to be able to form,

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and then water so everything
is present, and things

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are able to just grab all
these resources and energy

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and just start
to evolve.

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On Earth, hydrothermal
vents produce methane,

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but only in small amounts.

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Microbial life

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living around the vents
makes the rest.

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Maybe microorganisms
do the same

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at the bottom of Enceladus's
deep oceans.

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Hydrothermal vents on
Enceladus could offer

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the perfect location
for chemistry

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becoming biochemistry
becoming life.

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Hydrothermal vents
normally require

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heat from a hot core.

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heat from a hot core.

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So what's going on
inside Enceladus?

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This is an icy moon out there
in the cold outer solar system.

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Where is all this heat
coming from?

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Cassini spotted
Enceladus's plumes

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shooting out
from parallel cracks

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in the surface,
called tiger stripes.

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The cracks are a clue to
the origin of the geysers

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and the energy that
powers them.

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We look to the orbit of
Enceladus itself.

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It's not in a perfectly
circular orbit

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around the planet.

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It's on a slightly elliptical
orbit, and that means that

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the tidal forces acting on
the moon change over time.

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It's a little bit like
the forces on a rubber ball.

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When the moon is closer to
the planet, it's stretched out,

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and when the moon is
farther from the planet,

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and when the moon is
farther from the planet,

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it's relaxed back a little bit,
so you're gonna squeeze

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and deform and squish
the body of

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that moon over time, which is
gonna heat its interior.

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The warm, rocky core
heats up the ocean,

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which both powers the geysers
as they burst

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through the surface

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and creates conditions that
could support life.

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We see the energy source
kicking the water

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out of
the Enceladus subsurface.

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You combine that energy source

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and liquid water,
that harkens to putting

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us on the same path
that early life

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may have taken
here on the Earth.

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And if that's the case,

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there could be little beasties
swimming underneath the surface

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of one of Saturn's moons.

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Saturn's squeezing of
Enceladus may

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have transformed it into
a living world,

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but other moons
weren't as lucky.

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but other moons
weren't as lucky.

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They've been torn apart in
vicious fights

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to the death.

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There are a huge variety
of moons orbiting Saturn,

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from Titan, a moon larger
than the planet Mercury,

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to objects about the size of
a sports stadium.

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There must be
something dramatic that happened

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to create a system

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that's so complicated
and changing

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before our very eyes.

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before our very eyes.

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To understand such
a marked difference in size,

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scientists look for clues in
the moon's orbits around

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Saturn itself.

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Most of the moons of that system
orbit in the same direction.

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That's obviously not
a coincidence.

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That's motion left over
from the formation

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of our solar system.

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This suggests the moons
formed around

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the same time as Saturn did.

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4.6 billion years ago,

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4.6 billion years ago,

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the ringless gas giant
grows from gas,

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rock, and ice in
the protoplanetary disk,

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along with a family
of moons.

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This origin story works for
most of Saturn's moons,

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but not for the recently
discovered objects orbiting

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in the opposite direction of
the planet's rotation.

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If there's a moon orbiting in
the other direction,

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If there's a moon orbiting in
the other direction,

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it couldn't have formed with
the planet.

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It must have come from
somewhere else.

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Saturn captured these moons.

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But from where?

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We think there was a huge
upheaval in the solar system

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over four billion years ago,

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where the giant planets

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went from a close and compact
configuration, started

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having interactions
with each other,

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moved each other around
to end up into the orbits

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that they find today.

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that they find today.

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During that process, a lot of
smaller bodies,

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like asteroids
from the distant part

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of the solar system
got scattered

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every which direction.

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During
this ancient upheaval,

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Saturn grabs some of
the scattered objects.

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Many bodies now crowd
the region around the planet,

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and that means collisions.

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Some are destructive.

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Some are destructive.

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Others form new moons.

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In the cosmic pinball,

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some moons are thrown
out of the system,

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and others,
into Saturn.

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Only one large moon
survives the carnage.

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And all of a sudden,
most of the mass

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of all the satellites is in
that single moon, Titan.

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Titan may have formed
from the material in

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the protoplanetary disk at
the same time as Saturn,

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the protoplanetary disk at
the same time as Saturn,

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but then gorged on the debris
created in the later

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lunar collisions.

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It amassed 96 percent of
the material orbiting Saturn

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and grew so large that it
developed a dense atmosphere.

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When Voyager
photographed Titan,

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it clearly showed that Titan
had a thick atmosphere,

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which was so
incredibly exciting,

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which was so
incredibly exciting,

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but it was so dense
and impenetrable,

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that was all we could see.

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Two decades after Voyager,

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the Huygens Probe
launched from Cassini

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and plunged through the murky
depths of Titan's atmosphere.

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Our first images of what

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the Titanic landscape was like

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were utterly and truly
mind-blowing.

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were utterly and truly
mind-blowing.

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It showed there were mountains

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and there was
sort of erosion

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on those mountains
that looked like liquid

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had fallen down the mountains
and brought material with it.

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That liquid must
have come from somewhere.

252
00:14:01,367 --> 00:14:03,200
And where else than rain,

253
00:14:03,266 --> 00:14:04,467
the weather on Titan?

254
00:14:06,100 --> 00:14:08,867
We've only found
two places in the solar system

255
00:14:08,867 --> 00:14:12,000
with rivers and rain --

256
00:14:12,100 --> 00:14:15,867
Earth and Titan.

257
00:14:15,967 --> 00:14:16,919
Out of this thick gloom,

258
00:14:16,919 --> 00:14:18,200
Out of this thick gloom,

259
00:14:18,266 --> 00:14:22,367
this is the most similar place
to Earth we've ever seen.

260
00:14:22,467 --> 00:14:25,467
Similar,
but not identical.

261
00:14:27,266 --> 00:14:32,200
That rain filling lakes and
rivers on Titan isn't water.

262
00:14:33,266 --> 00:14:34,600
It's liquid methane.

263
00:14:36,066 --> 00:14:39,467
It's like if every oil well,
if every gas station on

264
00:14:39,567 --> 00:14:41,567
Earth started leaking
all over the place,

265
00:14:41,567 --> 00:14:44,200
that is what we see on
this world.

266
00:14:47,066 --> 00:14:48,867
The methane is
a liquid on Titan

267
00:14:48,967 --> 00:14:53,567
because the surface temperature
is 290 degrees below zero,

268
00:14:54,867 --> 00:14:57,266
which is a big problem
for life

269
00:14:57,367 --> 00:14:59,266
as we understand it.

270
00:15:00,767 --> 00:15:03,667
We don't know of any organism
that can really survive past

271
00:15:03,767 --> 00:15:06,166
negative 4 degrees Fahrenheit,
and that's just because

272
00:15:06,266 --> 00:15:08,800
cells will tend
to freeze there.

273
00:15:08,867 --> 00:15:10,567
The cells that we have,

274
00:15:10,567 --> 00:15:13,467
what they're made up from,
these proteins and fatty

275
00:15:13,567 --> 00:15:16,919
material, stop working,
and everything would die.

276
00:15:16,919 --> 00:15:17,800
material, stop working,
and everything would die.

277
00:15:17,867 --> 00:15:22,500
That's what happens to
Earth's water-based cells.

278
00:15:25,200 --> 00:15:30,300
But could methane-based life
survive in extreme cold?

279
00:15:33,066 --> 00:15:36,667
The ALMA telescope spotted
a clue in Titan's nitrogen-

280
00:15:36,667 --> 00:15:39,500
and-methane-rich atmosphere.

281
00:15:39,567 --> 00:15:43,367
With sunlight hitting
the atmosphere of Titan,

282
00:15:43,467 --> 00:15:46,667
things like methane and
nitrogen can get broken apart

283
00:15:46,667 --> 00:15:46,919
and reassembled,
like playing with LEGO blocks,

284
00:15:46,919 --> 00:15:50,867
and reassembled,
like playing with LEGO blocks,

285
00:15:50,967 --> 00:15:54,166
and then these molecules
recombine to

286
00:15:54,266 --> 00:15:57,166
make new ones,
like vinyl cyanide.

287
00:15:59,200 --> 00:16:01,166
Artist depiction.

288
00:16:01,266 --> 00:16:06,767
Used on Earth to make
plastics, vinyl cyanide can

289
00:16:06,867 --> 00:16:09,100
build long chains of molecules,

290
00:16:09,166 --> 00:16:12,700
the type you need to build
cell membranes.

291
00:16:18,767 --> 00:16:21,467
But unlike Earth's
water-based cells,

292
00:16:21,567 --> 00:16:24,367
the extreme cold wouldn't
destroy them.

293
00:16:26,900 --> 00:16:29,100
It could survive
at those low temperatures.

294
00:16:29,166 --> 00:16:33,166
So on Titan, it could be that
this vinyl cyanide is able

295
00:16:33,266 --> 00:16:34,700
to form the membranes

296
00:16:34,767 --> 00:16:36,500
that are required
for cells to develop,

297
00:16:36,567 --> 00:16:39,200
which are required
for life to happen.

298
00:16:43,000 --> 00:16:45,166
And good news --

299
00:16:45,266 --> 00:16:46,919
there's a lot of this stuff
on Titan right now.

300
00:16:46,919 --> 00:16:48,200
there's a lot of this stuff
on Titan right now.

301
00:16:50,867 --> 00:16:55,300
There's as much as 10 billion
tons of this vinyl cyanide

302
00:16:55,367 --> 00:16:56,767
in just one of the lakes.

303
00:16:56,867 --> 00:16:58,867
If you want to start
making creatures out of it --

304
00:16:58,867 --> 00:17:00,767
say, I don't know,
a giant squid --

305
00:17:00,767 --> 00:17:02,266
do you like giant squids?

306
00:17:02,367 --> 00:17:05,767
I hope so, because you could
make billions

307
00:17:05,767 --> 00:17:11,266
of giant squids out of
this vinyl cyanide.

308
00:17:11,266 --> 00:17:14,166
Saturn's geyser moon,
Enceladus,

309
00:17:14,166 --> 00:17:16,667
could have life as we know it.

310
00:17:16,767 --> 00:17:16,919
Titan might have
something truly alien.

311
00:17:16,919 --> 00:17:21,700
Titan might have
something truly alien.

312
00:17:21,767 --> 00:17:25,200
It is
an unrelentingly brutal,

313
00:17:25,266 --> 00:17:28,200
cold place
compared to Earth.

314
00:17:28,266 --> 00:17:31,667
But for Titanic life,
it might just be ideal.

315
00:17:33,266 --> 00:17:34,767
As we search for life
beyond Earth,

316
00:17:34,867 --> 00:17:38,266
it still comes with a bias of
life as we know it.

317
00:17:38,367 --> 00:17:40,400
And so it's great,
as we continue

318
00:17:40,467 --> 00:17:43,300
to explore and continue to
evolve our definitions,

319
00:17:43,367 --> 00:17:46,919
we can expand our view
of how to search for life.

320
00:17:46,919 --> 00:17:48,266
we can expand our view
of how to search for life.

321
00:17:48,367 --> 00:17:52,400
Maybe the Saturn system
has two living worlds.

322
00:17:54,800 --> 00:17:58,867
But for life to thrive
on Titan's surface,

323
00:17:58,867 --> 00:18:02,767
it must survive a storm of
deadly particles

324
00:18:02,767 --> 00:18:04,867
racing out of the Sun

325
00:18:04,867 --> 00:18:07,000
at over a million miles
an hour.

326
00:18:22,600 --> 00:18:25,567
The sun provides
light and warmth...

327
00:18:29,367 --> 00:18:34,000
and something else,
something very dangerous --

328
00:18:34,100 --> 00:18:35,100
the solar wind.

329
00:18:38,567 --> 00:18:41,767
These lethal solar particles
can strip away

330
00:18:41,767 --> 00:18:44,860
atmosphere from planets
and moons.

331
00:18:44,860 --> 00:18:44,967
atmosphere from planets
and moons.

332
00:18:48,300 --> 00:18:50,300
Without an atmosphere,

333
00:18:50,367 --> 00:18:52,767
Earth would be
a barren desert, right?

334
00:18:52,767 --> 00:18:55,367
There wouldn't be any water,
it would just all boil away.

335
00:18:55,467 --> 00:18:57,567
There wouldn't be any life,

336
00:18:58,700 --> 00:19:02,667
Luckily, Earth has
a built-in defense system.

337
00:19:04,100 --> 00:19:05,400
In the center of our Earth,

338
00:19:05,467 --> 00:19:09,867
we have a solid iron core, and
surrounding that is liquid iron

339
00:19:09,867 --> 00:19:14,000
that is constantly moving
and swirling and convecting,

340
00:19:14,100 --> 00:19:14,860
and these complex motions

341
00:19:14,860 --> 00:19:15,567
and these complex motions

342
00:19:15,667 --> 00:19:19,567
power up a global-scale
magnetic field

343
00:19:23,266 --> 00:19:25,166
And this acts
like a force field

344
00:19:25,266 --> 00:19:27,800
against the solar wind,
pushes it away,

345
00:19:27,867 --> 00:19:29,667
pushes it around us
so it doesn't hit us.

346
00:19:31,266 --> 00:19:34,400
We think
that Saturn's moon, Titan,

347
00:19:34,467 --> 00:19:37,066
has no molten iron core

348
00:19:39,567 --> 00:19:43,800
and therefore no protective
magnetic field.

349
00:19:43,867 --> 00:19:44,860
So it's at the mercy of
the solar wind.

350
00:19:44,860 --> 00:19:46,500
So it's at the mercy of
the solar wind.

351
00:19:47,667 --> 00:19:50,200
It kind of begs the question,
why does Titan

352
00:19:50,266 --> 00:19:52,767
have such a thick,
dense atmosphere?

353
00:19:52,867 --> 00:19:57,367
Titan retaining
an atmosphere without

354
00:19:57,467 --> 00:20:00,266
a protective shield
makes no sense.

355
00:20:03,000 --> 00:20:05,100
Titan doesn't have
a magnetic field,

356
00:20:05,166 --> 00:20:07,567
but Saturn does.

357
00:20:07,567 --> 00:20:10,300
So maybe there's some sort of
interaction between

358
00:20:10,367 --> 00:20:14,860
the atmosphere of Titan and
Saturn's giant magnetic field.

359
00:20:14,860 --> 00:20:15,000
the atmosphere of Titan and
Saturn's giant magnetic field.

360
00:20:16,767 --> 00:20:20,166
The gas giant Saturn
generates a magnetic field

361
00:20:20,166 --> 00:20:23,166
around 600 times larger
than Earth's,

362
00:20:25,667 --> 00:20:29,367
large enough to shield Titan
from the solar wind.

363
00:20:31,700 --> 00:20:35,066
So Titan by itself
is vulnerable.

364
00:20:35,066 --> 00:20:36,900
Saturn is like
the mother ship.

365
00:20:37,000 --> 00:20:39,500
It has this giant
force field

366
00:20:39,567 --> 00:20:41,000
that it can use
to protect Titan.

367
00:20:42,400 --> 00:20:44,860
Despite Saturn's embrace,
Titan still loses

368
00:20:44,860 --> 00:20:48,300
Despite Saturn's embrace,
Titan still loses

369
00:20:48,367 --> 00:20:52,567
some of its atmosphere,
because occasionally,

370
00:20:52,667 --> 00:20:57,166
the moon wanders away from its
protective parent.

371
00:20:57,266 --> 00:21:00,667
Titan orbits inside of
that magnetic field...

372
00:21:00,667 --> 00:21:03,266
mostly, most of the time.

373
00:21:03,266 --> 00:21:05,000
Its orbit isn't
perfectly circular.

374
00:21:05,100 --> 00:21:06,700
It's slightly elliptical.

375
00:21:08,467 --> 00:21:11,667
So as Titan orbits the planet,
for a little bit of time,

376
00:21:11,667 --> 00:21:13,000
about 5 percent of its orbit,

377
00:21:13,066 --> 00:21:14,860
it's actually slightly outside
the magnetic field

378
00:21:14,860 --> 00:21:15,467
it's actually slightly outside
the magnetic field

379
00:21:15,467 --> 00:21:17,100
before dipping back
in again.

380
00:21:19,667 --> 00:21:21,100
But these short forays into

381
00:21:21,166 --> 00:21:25,667
the firing line don't cause
any lasting damage.

382
00:21:26,967 --> 00:21:30,166
What's really weird is that
there's sort of a residual

383
00:21:30,266 --> 00:21:32,266
magnetic effect on Titan.

384
00:21:32,266 --> 00:21:34,567
When it leaves Saturn's
protective field,

385
00:21:34,567 --> 00:21:37,000
it should just immediately
drop to nothing.

386
00:21:37,066 --> 00:21:39,300
But there still is
this residual field,

387
00:21:39,367 --> 00:21:41,867
protecting it from
the solar wind.

388
00:21:41,867 --> 00:21:44,860
It can maintain the
memory of that magnetic field

389
00:21:44,860 --> 00:21:45,100
It can maintain the
memory of that magnetic field

390
00:21:45,166 --> 00:21:48,000
and still preserve some
of that protection.

391
00:21:49,300 --> 00:21:52,100
It's almost like Saturn is
trying to teach

392
00:21:52,166 --> 00:21:54,166
Titan how to have
a magnetic field,

393
00:21:54,166 --> 00:21:56,000
and Titan can remember
for a little bit,

394
00:21:56,066 --> 00:21:58,000
but then it needs to come
back home.

395
00:21:59,867 --> 00:22:02,367
This magnetic memory
could help

396
00:22:02,467 --> 00:22:05,600
support any life on
Titan's surface,

397
00:22:05,667 --> 00:22:09,667
providing a safe haven that's
protected from the solar wind.

398
00:22:12,266 --> 00:22:14,200
And Cassini spots a way

399
00:22:14,266 --> 00:22:14,860
Saturn's magnetism
might also allow

400
00:22:14,860 --> 00:22:17,367
Saturn's magnetism
might also allow

401
00:22:17,467 --> 00:22:20,667
its moons to develop life.

402
00:22:20,667 --> 00:22:24,767
One of the most amazing
discoveries around Saturn was

403
00:22:24,867 --> 00:22:26,500
that its magnetic field is not

404
00:22:26,567 --> 00:22:28,667
just transporting
charged particles from,

405
00:22:28,767 --> 00:22:32,266
say, the sun, but it's also
transporting material

406
00:22:32,367 --> 00:22:33,800
from one moon to another.

407
00:22:37,166 --> 00:22:39,567
Saturn's magnetic field
helps boost

408
00:22:39,567 --> 00:22:41,867
the chance of life on Titan

409
00:22:41,867 --> 00:22:44,860
by stealing material
from its sister moon, Enceladus.

410
00:22:44,860 --> 00:22:46,867
by stealing material
from its sister moon, Enceladus.

411
00:22:48,166 --> 00:22:50,667
Magnetism is
a strong force, of course,

412
00:22:50,667 --> 00:22:53,567
but to act on a scale
and a range

413
00:22:53,567 --> 00:22:56,300
like this and maybe transport
matter from moon to moon,

414
00:22:56,367 --> 00:22:58,066
that's pretty cool.

415
00:22:59,800 --> 00:23:02,867
Saturn's magnetic field
smashes apart

416
00:23:02,967 --> 00:23:07,367
water molecules blasted out
from Enceladus's geysers

417
00:23:07,467 --> 00:23:12,600
and carries the leftover oxygen
to Titan.

418
00:23:12,667 --> 00:23:14,767
The magnetic field of Saturn

419
00:23:14,867 --> 00:23:18,100
acts like
an inter-lunar highway

420
00:23:18,166 --> 00:23:21,667
in the Saturn system,
transporting oxygen

421
00:23:21,667 --> 00:23:24,500
from Enceladus all the way
to Titan.

422
00:23:24,567 --> 00:23:28,166
But there's a problem
when the oxygen tries to

423
00:23:28,266 --> 00:23:33,066
take the Titan exit off of
this inter-lunar highway.

424
00:23:33,066 --> 00:23:36,200
Normally, this oxygen
wouldn't survive

425
00:23:36,266 --> 00:23:37,567
in the atmosphere of Titan.

426
00:23:37,667 --> 00:23:40,467
It would react with the methane
there and create carbon dioxide.

427
00:23:41,967 --> 00:23:43,700
To get to the surface

428
00:23:43,767 --> 00:23:44,860
in one piece,
oxygen hitches

429
00:23:44,860 --> 00:23:46,166
in one piece,
oxygen hitches

430
00:23:46,166 --> 00:23:49,567
a ride with something
called a fullerene.

431
00:23:54,467 --> 00:23:55,967
Fullerenes are these sort of

432
00:23:55,967 --> 00:23:58,500
soccer ball shaped molecules
that are hollow.

433
00:23:58,567 --> 00:24:00,667
If the oxygen atom
gets in there,

434
00:24:00,667 --> 00:24:03,867
it can be safely transported
through Titan's atmosphere.

435
00:24:05,767 --> 00:24:09,600
Once on the surface,
the oxygen could help create

436
00:24:09,667 --> 00:24:11,467
amino acids,

437
00:24:11,467 --> 00:24:14,400
the essential building blocks
of proteins,

438
00:24:14,467 --> 00:24:14,860
another stepping stone for
life to emerge.

439
00:24:14,860 --> 00:24:19,100
another stepping stone for
life to emerge.

440
00:24:22,367 --> 00:24:25,767
Think of all
the complex coincidences

441
00:24:25,867 --> 00:24:27,567
that have to happen

442
00:24:27,667 --> 00:24:30,667
for these chemical reactions
to take place.

443
00:24:30,667 --> 00:24:32,667
If Titan's orbit
was any different,

444
00:24:32,767 --> 00:24:34,100
it simply wouldn't exist.

445
00:24:37,767 --> 00:24:42,367
Saturn protects
any potential life on its moons.

446
00:24:43,600 --> 00:24:44,860
And as it turns out,
the moons

447
00:24:44,860 --> 00:24:46,166
And as it turns out,
the moons

448
00:24:46,166 --> 00:24:50,667
return the favor
by helping create

449
00:24:50,767 --> 00:24:57,000
and maintain
Saturn's iconic rings.

450
00:25:10,467 --> 00:25:13,800
At 170,000 miles
in diameter,

451
00:25:15,000 --> 00:25:17,500
but only 30 feet thick
in places,

452
00:25:17,567 --> 00:25:22,367
Saturn's beautiful rings have
always stolen the show,

453
00:25:25,266 --> 00:25:29,367
but their origin is still
a mystery.

454
00:25:29,467 --> 00:25:29,965
Saturn has these beautiful
rings that really

455
00:25:29,965 --> 00:25:33,066
Saturn has these beautiful
rings that really

456
00:25:33,066 --> 00:25:34,300
define it as a planet,

457
00:25:34,367 --> 00:25:36,467
but its unique in the solar
system in the sense that no

458
00:25:36,567 --> 00:25:40,100
other planet has such
a big ring system.

459
00:25:40,166 --> 00:25:44,100
All of the other gas
giants have remnants of a ring,

460
00:25:44,166 --> 00:25:47,967
kind of small, thin, dark rings,
but nothing like Saturn.

461
00:25:47,967 --> 00:25:51,000
So something very different
happened around Saturn.

462
00:25:53,000 --> 00:25:57,600
A clue comes from
the rings' composition.

463
00:25:57,667 --> 00:25:59,965
They're around
99 percent water ice,

464
00:25:59,965 --> 00:26:00,500
They're around
99 percent water ice,

465
00:26:00,567 --> 00:26:03,467
giving the rings
their sparkling appearance.

466
00:26:05,000 --> 00:26:09,400
This leads astronomers
to a bold theory.

467
00:26:09,467 --> 00:26:13,100
We do not know how Saturn's
icy rings formed.

468
00:26:13,166 --> 00:26:14,767
We're not even sure
how old they are,

469
00:26:14,767 --> 00:26:18,266
but one idea is that
they formed from ice that was

470
00:26:18,367 --> 00:26:20,567
existing previously on a moon.

471
00:26:20,667 --> 00:26:23,400
How amazing is that?

472
00:26:23,467 --> 00:26:28,467
Several billion years ago,
Saturn may have been ringless,

473
00:26:29,667 --> 00:26:29,965
with a large, icy moon.

474
00:26:29,965 --> 00:26:32,166
with a large, icy moon.

475
00:26:32,266 --> 00:26:35,867
The moon was big enough that
its gravity drew heavier

476
00:26:35,967 --> 00:26:37,767
stuff like rock to its core

477
00:26:37,767 --> 00:26:40,467
and lighter stuff like ice
floated to the top.

478
00:26:40,567 --> 00:26:47,266
We think the moon
strayed too close to Saturn.

479
00:26:47,266 --> 00:26:50,367
The gravity from Saturn
could tear it apart,

480
00:26:52,200 --> 00:26:55,266
and it could separate the ices
from the rocky parts

481
00:26:55,266 --> 00:26:57,767
and the ices could stay in
orbit and form our rings,

482
00:26:57,767 --> 00:26:59,965
and the rocky parts would get
swallowed up by Saturn.

483
00:26:59,965 --> 00:27:00,667
and the rocky parts would get
swallowed up by Saturn.

484
00:27:07,066 --> 00:27:10,667
The death of a large moon
may have built the rings,

485
00:27:14,867 --> 00:27:18,967
but they owe their current
appearance to the moons that

486
00:27:18,967 --> 00:27:20,900
are still alive.

487
00:27:21,000 --> 00:27:24,266
When you go back
to Saturn's rings,

488
00:27:24,266 --> 00:27:27,100
time and time again,
they're all slightly different.

489
00:27:27,166 --> 00:27:29,166
They are changing, they are
braiding in and out of

490
00:27:29,166 --> 00:27:29,965
each other -- we had no idea
there would be

491
00:27:29,965 --> 00:27:32,000
each other -- we had no idea
there would be

492
00:27:32,100 --> 00:27:34,567
so much beauty and so much
mystery in the rings.

493
00:27:36,467 --> 00:27:40,266
The behavior of two of
Saturn's moons,

494
00:27:40,266 --> 00:27:42,567
Prometheus and Atlas,

495
00:27:42,667 --> 00:27:45,100
which are embedded in
the rings

496
00:27:45,166 --> 00:27:47,300
is especially surprising.

497
00:27:47,367 --> 00:27:50,567
Some of these smallest moons

498
00:27:50,667 --> 00:27:53,467
are interspersed within
the ring system.

499
00:27:53,567 --> 00:27:57,767
Some of them are doing
something really bizarre.

500
00:27:57,867 --> 00:27:59,965
In some cases, it looks like
the moons were shepherding

501
00:27:59,965 --> 00:28:01,266
In some cases, it looks like
the moons were shepherding

502
00:28:01,266 --> 00:28:04,767
the edges of the rings and
keeping them in their place.

503
00:28:06,000 --> 00:28:09,567
The moon's gravity
cleans up the rings,

504
00:28:10,867 --> 00:28:14,367
sometimes, sculpting shapes
in their wake.

505
00:28:16,667 --> 00:28:19,567
Saturn's rings aren't static,
and there's some really

506
00:28:19,567 --> 00:28:22,500
fascinating interactions where
moons are clearly pushing on

507
00:28:22,567 --> 00:28:25,467
the rings and causing weird
and cool waves,

508
00:28:25,567 --> 00:28:29,900
making the rings just
that much more beautiful.

509
00:28:30,000 --> 00:28:33,367
The whole dance between
Saturn and its moons,

510
00:28:33,367 --> 00:28:35,166
its rings,
how they all

511
00:28:35,266 --> 00:28:37,900
are interconnected, is just
completely fascinating.

512
00:28:40,100 --> 00:28:41,667
It's a dynamic, amazing,

513
00:28:41,767 --> 00:28:44,200
living, geologically
vibrant place.

514
00:28:48,266 --> 00:28:51,266
Saturn's moons may keep
the rings orderly,

515
00:28:53,200 --> 00:28:58,166
but they can't explain
why the rings are so clean,

516
00:28:58,166 --> 00:28:59,667
almost pristine.

517
00:29:02,100 --> 00:29:03,667
They're too shiny.

518
00:29:03,667 --> 00:29:06,100
If they were billions of
years old,

519
00:29:06,166 --> 00:29:08,500
they should have collected
a lot of dust by now

520
00:29:08,567 --> 00:29:09,767
and be a lot darker.

521
00:29:09,867 --> 00:29:12,767
The fact that they're shiny
kind of implies that

522
00:29:12,767 --> 00:29:16,600
maybe they're a lot younger
than we first thought.

523
00:29:16,667 --> 00:29:19,467
Perhaps
the rings we see today

524
00:29:19,467 --> 00:29:22,367
are a more recent upgrade.

525
00:29:23,867 --> 00:29:26,667
The rings might only be
100 million years old,

526
00:29:26,667 --> 00:29:28,800
about the time of
the dinosaurs.

527
00:29:28,867 --> 00:29:29,965
So if the dinosaurs
had invented telescopes,

528
00:29:29,965 --> 00:29:31,867
So if the dinosaurs
had invented telescopes,

529
00:29:31,967 --> 00:29:34,867
they could have seen Saturn
without rings.

530
00:29:34,867 --> 00:29:36,100
And it makes you wonder,
is this

531
00:29:36,166 --> 00:29:38,166
the first ring system that
Saturn had?

532
00:29:38,166 --> 00:29:39,967
Or was there another
ring system

533
00:29:39,967 --> 00:29:42,000
that may be slowly
eroded away?

534
00:29:42,100 --> 00:29:45,266
Perhaps a comet or a body came
in too close to Saturn,

535
00:29:45,367 --> 00:29:47,367
and Saturn's gravity
literally tore it apart,

536
00:29:47,367 --> 00:29:49,200
and then we got a brand-new
ring system.

537
00:29:51,567 --> 00:29:54,300
The later dinosaurs could have
watched the rings form,

538
00:29:55,467 --> 00:29:57,266
and then they would have been
wiped out by an asteroid.

539
00:29:58,567 --> 00:29:59,965
Yeah, should have built
better telescopes,

540
00:29:59,965 --> 00:30:00,367
Yeah, should have built
better telescopes,

541
00:30:00,367 --> 00:30:02,867
dinosaurs, sucks to be you.

542
00:30:05,567 --> 00:30:08,600
We still don't know
why the rings of Saturn

543
00:30:08,667 --> 00:30:10,266
are so clean.

544
00:30:11,967 --> 00:30:14,166
It could be that the rings
really are old, and they have

545
00:30:14,166 --> 00:30:15,500
some sort of cleaning system,

546
00:30:15,567 --> 00:30:17,000
which removes the dust
from them,

547
00:30:17,066 --> 00:30:21,600
making them look young, or they
may actually be young, and this

548
00:30:21,667 --> 00:30:24,867
may be the seventh or eighth
or whatever generation rings.

549
00:30:24,867 --> 00:30:29,965
It is so different than
any other planetary system.

550
00:30:29,965 --> 00:30:29,967
It is so different than
any other planetary system.

551
00:30:29,967 --> 00:30:31,867
And those mysteries
still exist.

552
00:30:31,967 --> 00:30:35,667
We have some idea
what went on,

553
00:30:35,767 --> 00:30:38,066
but there's a lot that
we don't know about Saturn.

554
00:30:40,867 --> 00:30:43,600
Cassini is changing that.

555
00:30:46,000 --> 00:30:50,000
It's discovered a whole new
moon-making process,

556
00:30:52,166 --> 00:30:55,000
with the rings
taking the lead.

557
00:31:10,967 --> 00:31:13,767
Midway through its 13-year
mission to Saturn,

558
00:31:16,166 --> 00:31:19,000
Cassini captures
an intriguing image,

559
00:31:21,667 --> 00:31:23,700
a bright feature
at the edge

560
00:31:23,767 --> 00:31:26,000
of one of Saturn's
outermost rings,

561
00:31:27,066 --> 00:31:29,000
something we'd never
seen before.

562
00:31:31,400 --> 00:31:34,600
I was really excited when
we saw these images of Saturn's

563
00:31:34,667 --> 00:31:36,967
rings, and it looked
like there was a lump,

564
00:31:36,967 --> 00:31:41,600
maybe a moon forming there,
which they nicknamed Peggy.

565
00:31:41,667 --> 00:31:43,667
Named after the mother-in-law

566
00:31:43,767 --> 00:31:45,800
of the scientist
who discovered it,

567
00:31:45,867 --> 00:31:49,200
Peggy was still too small
to be considered

568
00:31:49,266 --> 00:31:54,967
a fully-formed moon,
but nearby orbits

569
00:31:54,967 --> 00:31:59,300
a group of objects that are
just big enough to be moons,

570
00:32:02,166 --> 00:32:04,300
and they are really weird.

571
00:32:05,900 --> 00:32:07,467
These moons are
really unusual.

572
00:32:07,567 --> 00:32:10,467
We don't think of them as like
anything else we've seen.

573
00:32:10,567 --> 00:32:14,166
They're kind of
little fuzzy potatoes or maybe

574
00:32:14,266 --> 00:32:17,367
even like a ravioli is another
one or a croissant.

575
00:32:17,367 --> 00:32:18,567
Why do we always come up
with food?

576
00:32:18,667 --> 00:32:22,000
But at the same time, that's
exactly what they look like.

577
00:32:22,066 --> 00:32:25,367
The most bizarrely-shaped moon
of Saturn is Pan.

578
00:32:25,467 --> 00:32:27,200
It's got these
crisscrossing cracks,

579
00:32:27,266 --> 00:32:30,100
just like bread,
and then around the outside

580
00:32:30,166 --> 00:32:32,367
is a belly band,
it's undulatory.

581
00:32:32,367 --> 00:32:34,000
How would this get there?

582
00:32:36,700 --> 00:32:39,266
Cassini
discovered a clue.

583
00:32:42,100 --> 00:32:44,200
Like Saturn's rings,

584
00:32:44,266 --> 00:32:48,166
these moons were made almost
entirely of water ice.

585
00:32:51,166 --> 00:32:52,367
They must have grown from

586
00:32:52,367 --> 00:32:55,567
tiny lumps trapped
within the rings.

587
00:32:56,667 --> 00:33:00,158
They're going to be
extremely fragile,

588
00:33:00,158 --> 00:33:02,767
They're going to be
extremely fragile,

589
00:33:02,867 --> 00:33:05,400
kind of like a snowflake
orbiting Saturn.

590
00:33:05,467 --> 00:33:08,367
They can start drawing in
material and then can grow.

591
00:33:08,467 --> 00:33:10,967
You can actually imagine
rolling up a snowball

592
00:33:10,967 --> 00:33:13,867
and accumulating more and more
particles on the outside.

593
00:33:13,867 --> 00:33:16,400
And in the same way,
you could accumulate

594
00:33:16,467 --> 00:33:17,867
these clumps
in the rings.

595
00:33:17,967 --> 00:33:19,867
And if they're near
the edge of the rings,

596
00:33:19,967 --> 00:33:24,567
perhaps they actually break free
and go out to form tiny moons.

597
00:33:27,266 --> 00:33:30,158
The size of
these space snowballs,

598
00:33:30,158 --> 00:33:30,667
The size of
these space snowballs,

599
00:33:30,767 --> 00:33:33,867
tens of miles across or less,

600
00:33:33,967 --> 00:33:36,467
helps explain
their unusual shapes.

601
00:33:39,800 --> 00:33:43,567
The size of the moon actually
affects its shape in that once

602
00:33:43,567 --> 00:33:45,100
you get below a certain
size threshold,

603
00:33:45,166 --> 00:33:46,900
you cannot be round anymore.

604
00:33:47,000 --> 00:33:48,867
That's because the strength of
the rock or the ice

605
00:33:48,867 --> 00:33:51,667
in this case is too great
to be overcome by gravity,

606
00:33:51,667 --> 00:33:54,767
and so the kind of oblong
shapes can be maintained.

607
00:33:57,200 --> 00:33:59,266
Add in a few collisions,

608
00:33:59,367 --> 00:34:00,158
and you get Saturn's ravioli-
and croissant-shaped moons.

609
00:34:00,158 --> 00:34:03,467
and you get Saturn's ravioli-
and croissant-shaped moons.

610
00:34:06,266 --> 00:34:08,667
It's a bizarre process but
leads to a beautiful form.

611
00:34:08,767 --> 00:34:12,767
We know the moons affect
the rings, but it looks

612
00:34:12,867 --> 00:34:15,467
like in this case, the rings
affect the moons, too.

613
00:34:15,467 --> 00:34:17,500
They're connected
in both directions.

614
00:34:23,367 --> 00:34:26,467
The rings form
a moon factory,

615
00:34:30,467 --> 00:34:34,467
capable of building countless
generations of new worlds.

616
00:34:36,467 --> 00:34:40,000
This is a dance of physics.

617
00:34:42,000 --> 00:34:45,367
If moonlets can form
by these icy ring particles,

618
00:34:45,467 --> 00:34:47,767
they'll grow, and then
their natural gravitational

619
00:34:47,767 --> 00:34:50,300
interaction with the rings will
make them move out.

620
00:34:50,367 --> 00:34:51,900
They keep growing
as they move out.

621
00:34:52,000 --> 00:34:54,467
But then another moon forms
where the first one was.

622
00:34:54,567 --> 00:34:57,467
So you keep getting these
growing moons, right,

623
00:34:57,467 --> 00:34:59,800
and this process repeats
like on a conveyor belt.

624
00:34:59,867 --> 00:35:00,158
And what you wind up with is
bigger moons orbiting

625
00:35:00,158 --> 00:35:02,467
And what you wind up with is
bigger moons orbiting

626
00:35:02,467 --> 00:35:04,700
farther out from Saturn
and smaller ones

627
00:35:04,767 --> 00:35:06,000
orbiting closer in.

628
00:35:08,867 --> 00:35:12,567
But Saturn's conveyor belt
will eventually break down.

629
00:35:17,166 --> 00:35:18,600
When ultraviolet light from

630
00:35:18,667 --> 00:35:23,000
the sun interacts with
ring particles,

631
00:35:23,066 --> 00:35:27,200
it throws their steady orbit
around Saturn out of whack.

632
00:35:29,467 --> 00:35:30,158
The sun energizes the rings,
and it gives them a charge.

633
00:35:30,158 --> 00:35:32,567
The sun energizes the rings,
and it gives them a charge.

634
00:35:32,567 --> 00:35:34,166
This charge means
they can get picked

635
00:35:34,166 --> 00:35:36,367
up by the magnetic field
of Saturn.

636
00:35:36,367 --> 00:35:38,900
So these little tiny charged
particles then are lifted

637
00:35:39,000 --> 00:35:40,266
out of the rings,

638
00:35:40,367 --> 00:35:42,400
follow along
the magnetic field lines,

639
00:35:42,467 --> 00:35:44,567
rain down into
Saturn's atmosphere.

640
00:35:47,166 --> 00:35:51,900
The charged particles
are tiny ice crystals.

641
00:35:52,000 --> 00:35:54,600
They rain down onto Saturn,

642
00:35:57,266 --> 00:36:00,158
enough to fill
an Olympic-sized swimming pool

643
00:36:00,158 --> 00:36:00,500
enough to fill
an Olympic-sized swimming pool

644
00:36:00,567 --> 00:36:01,667
every second.

645
00:36:05,467 --> 00:36:08,200
In less than
100 million years,

646
00:36:08,266 --> 00:36:12,300
Saturn's rings
will be gone.

647
00:36:12,367 --> 00:36:17,667
There will be no material
to build new moons.

648
00:36:17,667 --> 00:36:21,467
Saturn's moons and rings,

649
00:36:21,567 --> 00:36:23,700
they almost make me feel
bittersweet, because they

650
00:36:23,767 --> 00:36:26,667
show you the beauty of
what physics can create,

651
00:36:26,767 --> 00:36:28,767
But also the fleeting-ness.

652
00:36:28,767 --> 00:36:30,158
They'll be gone soon,
and that makes me sad.

653
00:36:30,158 --> 00:36:31,600
They'll be gone soon,
and that makes me sad.

654
00:36:34,667 --> 00:36:36,600
The closer we look,

655
00:36:36,667 --> 00:36:39,567
the more intriguing
the Saturn system becomes.

656
00:36:45,900 --> 00:36:48,100
And now, scientists

657
00:36:48,166 --> 00:36:50,266
have an audacious
new plan

658
00:36:53,567 --> 00:36:57,667
to fly a drone on one of
Saturn's moons.

659
00:37:09,467 --> 00:37:12,567
Saturn is one of
the most dynamic places

660
00:37:12,567 --> 00:37:15,200
in the solar system.

661
00:37:16,367 --> 00:37:18,166
We want to go back there,

662
00:37:18,266 --> 00:37:21,166
to explore its moons up close

663
00:37:21,166 --> 00:37:24,400
and hunt directly
for Life 2.0.

664
00:37:26,967 --> 00:37:29,200
For so long, we've been
emphasizing that to have

665
00:37:29,266 --> 00:37:30,351
a habitable planet,

666
00:37:30,351 --> 00:37:30,467
a habitable planet,

667
00:37:30,500 --> 00:37:32,600
you have to be warm, you have
to be close to your star.

668
00:37:33,867 --> 00:37:36,100
In fact, the most likely
chance we have to find

669
00:37:36,166 --> 00:37:39,567
life maybe way in the outer
solar system in Saturn's moons.

670
00:37:40,600 --> 00:37:43,266
But we won't know for sure
until we send

671
00:37:43,367 --> 00:37:45,667
another mission there,
specifically to look for life.

672
00:37:47,467 --> 00:37:49,300
The Huygens Probe gave us

673
00:37:49,367 --> 00:37:52,000
a tantalizing glimpse of
Titan's surface,

674
00:37:56,000 --> 00:37:59,066
but it wasn't equipped
to search for life.

675
00:38:00,867 --> 00:38:05,300
Now, scientists are
developing Dragonfly,

676
00:38:05,367 --> 00:38:10,000
a space helicopter that can
search for life.

677
00:38:12,100 --> 00:38:14,200
Dragonfly is
an amazing mission.

678
00:38:14,266 --> 00:38:16,367
We're sending this to Titan
to better

679
00:38:16,467 --> 00:38:19,166
understand how life might
arise in a very different

680
00:38:19,266 --> 00:38:20,200
context than Earth.

681
00:38:22,767 --> 00:38:24,667
One thing we know
absolutely for certain

682
00:38:24,767 --> 00:38:28,367
is that Titan has interesting,
complex chemistry.

683
00:38:28,467 --> 00:38:29,667
The question now is,

684
00:38:29,767 --> 00:38:30,351
does that chemistry actually
turn into biology?

685
00:38:30,351 --> 00:38:33,000
does that chemistry actually
turn into biology?

686
00:38:36,567 --> 00:38:40,367
The million-dollar question,
is this a living world?

687
00:38:47,300 --> 00:38:50,667
April 2021.

688
00:38:53,000 --> 00:38:56,467
We test the concept
of a space helicopter.

689
00:39:01,100 --> 00:39:04,000
Ingenuity making
the first remote flight on

690
00:39:04,066 --> 00:39:08,300
another world launches into
the thin Martian atmosphere.

691
00:39:10,266 --> 00:39:12,367
Mars is a really difficult
place to fly,

692
00:39:12,467 --> 00:39:16,266
because the atmosphere is 100
times thinner than Earth's.

693
00:39:16,367 --> 00:39:18,600
And remember, it's
the atmosphere that provides

694
00:39:18,667 --> 00:39:21,767
the support and the lift
for a helicopter to fly.

695
00:39:21,867 --> 00:39:23,266
So in order
for Ingenuity to fly,

696
00:39:23,266 --> 00:39:25,500
it had to spin
very fast in order

697
00:39:25,567 --> 00:39:27,000
to even get itself
off the ground.

698
00:39:31,667 --> 00:39:34,667
Fortunately, Titan's
thick atmosphere

699
00:39:34,767 --> 00:39:37,166
is much more
helicopter friendly.

700
00:39:39,667 --> 00:39:42,500
The contrast between Ingenuity
and the Dragonfly mission

701
00:39:42,567 --> 00:39:43,467
is really funny,

702
00:39:43,467 --> 00:39:46,400
because Mars has almost
no atmosphere,

703
00:39:46,467 --> 00:39:48,900
less than 1 percent the
atmospheric pressure of Earth.

704
00:39:49,000 --> 00:39:52,166
On Titan,
you have exactly the opposite.

705
00:39:52,166 --> 00:39:54,266
The air pressure near
the surface of Titan can be

706
00:39:54,266 --> 00:39:56,867
four times as much as
the air pressure on Earth.

707
00:39:56,867 --> 00:39:59,600
So for a helicopter
or something like a drone,

708
00:39:59,667 --> 00:40:00,351
something like
an octocopter,

709
00:40:00,351 --> 00:40:00,800
something like
an octocopter,

710
00:40:00,867 --> 00:40:04,100
the lower the gravity is
and the denser the atmosphere,

711
00:40:04,166 --> 00:40:05,367
the better you can fly.

712
00:40:06,200 --> 00:40:09,166
So Titan just begs to be
explored, because you get

713
00:40:09,166 --> 00:40:11,100
a lot of lift, and you can
actually carry heavy

714
00:40:11,166 --> 00:40:12,166
instruments with you.

715
00:40:13,500 --> 00:40:16,100
It allows you to fly
through the atmosphere,

716
00:40:16,166 --> 00:40:19,367
collect samples, and determine
what the prebiotic chemistry

717
00:40:19,367 --> 00:40:20,467
is on that moon.

718
00:40:22,467 --> 00:40:25,066
If ever there was a world
built for flying drones,

719
00:40:25,066 --> 00:40:27,100
it's Titan.

720
00:40:27,166 --> 00:40:30,351
Dragonfly is scheduled
to launch in 2027,

721
00:40:30,351 --> 00:40:31,066
Dragonfly is scheduled
to launch in 2027,

722
00:40:34,000 --> 00:40:36,767
arriving at Titan
around seven years later,

723
00:40:36,867 --> 00:40:41,100
completing the journey of moon
discovery that began

724
00:40:41,166 --> 00:40:43,567
with Voyager
and Cassini.

725
00:40:46,066 --> 00:40:47,767
We completely transformed

726
00:40:47,767 --> 00:40:51,166
our picture of the Saturn
system, the rings and the moons.

727
00:40:51,166 --> 00:40:52,867
It's a far more complex

728
00:40:52,867 --> 00:40:55,166
environment than
we ever dreamed possible.

729
00:40:55,166 --> 00:40:56,700
The moons have come
alive, right?

730
00:40:56,767 --> 00:40:59,867
They're not boring, dead
ice balls, and it just

731
00:40:59,967 --> 00:41:00,351
begs generation after generation
of spacecraft follow up.

732
00:41:00,351 --> 00:41:02,166
begs generation after generation
of spacecraft follow up.

733
00:41:05,300 --> 00:41:06,767
We're only
just beginning to

734
00:41:06,767 --> 00:41:09,667
unravel the secrets of
Saturn's moons.

735
00:41:12,100 --> 00:41:16,367
And with more than 80 to
explore, the Saturn system is

736
00:41:16,467 --> 00:41:19,000
a gift that'll keep on giving.

737
00:41:21,900 --> 00:41:24,567
Saturn was the very first
thing I ever

738
00:41:24,667 --> 00:41:26,567
saw through a telescope
when I was a kid.

739
00:41:26,567 --> 00:41:30,351
And here I am -- clearly,
I was inspired by Saturn,

740
00:41:30,351 --> 00:41:30,467
And here I am -- clearly,
I was inspired by Saturn,

741
00:41:30,567 --> 00:41:32,400
by its beauty.

742
00:41:32,467 --> 00:41:34,767
Saturn has always been
my favorite planet.

743
00:41:34,767 --> 00:41:36,100
Everything you want

744
00:41:36,166 --> 00:41:38,967
is there -- violence,
colliding moons,

745
00:41:38,967 --> 00:41:42,500
how new rings form, new moons
form over time.

746
00:41:43,867 --> 00:41:45,567
And there might be life there.

747
00:41:45,567 --> 00:41:49,000
There might be life in
more than one place there.

748
00:41:49,066 --> 00:41:53,000
One destination, one planetary
zip code, gives you all of that.

749
00:41:53,066 --> 00:41:54,500
I say go back to Saturn.

750
00:41:54,550 --> 00:41:59,100
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