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Orbiting the magnificent
ringed planet, Saturn,
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are a series of
extraordinary moons.
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00:00:13,867 --> 00:00:15,266
The closer that we look,
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00:00:15,367 --> 00:00:19,100
the more that we see its moons
are like worlds of their own --
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00:00:19,166 --> 00:00:20,800
so dynamic,
so Earth-like.
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00:00:21,867 --> 00:00:25,000
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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00:00:37,567 --> 00:00:38,800
in our solar system.
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00:00:42,800 --> 00:00:45,900
With each new mission,
we get closer
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00:00:46,000 --> 00:00:49,467
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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00:01:50,367 --> 00:01:52,000
The Voyager spacecraft
gave us our
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00:01:52,066 --> 00:01:55,200
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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00:02:05,867 --> 00:02:09,200
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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00:02:17,266 --> 00:02:21,467
There's Mimas,
that's fairly small,
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00:02:21,467 --> 00:02:23,700
and then Tethys and Dione
are a bit larger.
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00:02:25,166 --> 00:02:27,600
There are a pair of moons --
Janus and Epimetheus --
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00:02:27,667 --> 00:02:29,467
that were perhaps
one moon in the past.
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00:02:31,166 --> 00:02:33,300
Iapetus, half of it's
bright white.
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00:02:33,367 --> 00:02:34,667
The other half of it is
sort of as
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00:02:34,767 --> 00:02:37,100
dark as coal,
sort of yin and yang.
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00:02:39,367 --> 00:02:42,467
Each of
the moons of Saturn
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00:02:42,567 --> 00:02:45,367
had remarkable
stories to tell.
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00:02:46,467 --> 00:02:49,500
In 2005,
Cassini discovered that
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00:02:49,567 --> 00:02:53,767
one moon's story was
particularly exciting.
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Yeah, Enceladus.
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00:02:55,767 --> 00:02:58,767
Enceladus is one of Saturn's
wee little moons.
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00:02:58,767 --> 00:03:00,000
It's about 300 miles across --
for scale,
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00:03:00,000 --> 00:03:01,300
It's about 300 miles across --
for scale,
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00:03:01,367 --> 00:03:03,467
it's roughly the size
of Colorado.
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00:03:06,200 --> 00:03:09,367
The spacecraft's
cameras spot plumes of
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00:03:09,367 --> 00:03:12,567
water vapor shooting
out from Enceladus
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00:03:13,667 --> 00:03:15,400
at 800 miles an hour.
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00:03:18,467 --> 00:03:20,266
Three times as powerful than
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00:03:20,266 --> 00:03:22,900
all the hot springs
in Yellowstone.
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00:03:25,767 --> 00:03:29,066
The discovery of
geysers gushing out of tiny,
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00:03:29,066 --> 00:03:30,000
little Enceladus that should
have been cold and dead,
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00:03:30,000 --> 00:03:31,567
little Enceladus that should
have been cold and dead,
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00:03:31,567 --> 00:03:34,500
completely changed our view of
what that moon exactly was.
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00:03:36,066 --> 00:03:38,567
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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00:03:41,266 --> 00:03:43,300
see with the --
this water vapor
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00:03:43,367 --> 00:03:46,000
and ice crystals booming
out of the surface
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00:03:46,066 --> 00:03:47,667
at supersonic speeds.
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00:03:55,867 --> 00:03:59,500
Cassini's sensors
probe deep beneath
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00:03:59,567 --> 00:04:00,000
the frozen surface
of Enceladus,
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00:04:00,000 --> 00:04:01,667
the frozen surface
of Enceladus,
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00:04:01,667 --> 00:04:06,000
detecting hints
of a rocky core
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00:04:06,100 --> 00:04:09,100
and something else
even more remarkable.
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00:04:11,166 --> 00:04:13,667
Underneath that
thick layer of ice,
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00:04:13,767 --> 00:04:16,266
there is liquid
water ocean.
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00:04:16,266 --> 00:04:20,100
The measurements
suggest his is a huge part of
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00:04:20,166 --> 00:04:21,867
Enceladus's interior volume,
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00:04:21,967 --> 00:04:25,300
about six miles deep,
because it was making Enceladus
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00:04:25,367 --> 00:04:26,767
wobble in its orbit.
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00:04:26,867 --> 00:04:29,400
Imagine putting liquid inside
a ball and rolling it.
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00:04:29,467 --> 00:04:30,000
You see the natural wobble of
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00:04:30,000 --> 00:04:30,800
You see the natural wobble of
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the ball as the liquid
sloshes around.
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00:04:34,266 --> 00:04:38,667
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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00:04:49,266 --> 00:04:52,200
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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00:04:54,266 --> 00:04:56,767
I think Saturn's moons would
have been the last place
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00:04:56,867 --> 00:04:58,467
I would have picked.
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00:04:58,567 --> 00:05:00,000
But against all odds,
it's looking like this tiny icy
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00:05:00,000 --> 00:05:02,266
But against all odds,
it's looking like this tiny icy
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00:05:02,266 --> 00:05:03,800
moon orbiting Saturn
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00:05:03,867 --> 00:05:06,800
nearly a billion miles from
the Sun may be one of
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00:05:06,867 --> 00:05:09,266
the best places
to look for life.
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00:05:10,700 --> 00:05:14,066
July 2021.
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00:05:15,100 --> 00:05:18,467
A new study reexamines
Cassini's plume data
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00:05:20,100 --> 00:05:22,767
and finds huge quantities
of methane.
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This large amount can't be
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00:05:26,266 --> 00:05:29,467
explained by just
geochemical processes.
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The methane might be from
primordial organic matter
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00:05:35,266 --> 00:05:38,266
breaking down in
Enceladus's oceans,
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00:05:38,367 --> 00:05:47,867
or even processes
we've never seen before.
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00:05:47,967 --> 00:05:49,066
But it could be that
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00:05:49,100 --> 00:05:53,100
living microorganisms helped
generate the methane,
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00:05:53,166 --> 00:05:55,600
just like they do on Earth.
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00:05:56,967 --> 00:06:00,000
Enceladus might actually look
a lot like early Earth in its
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00:06:00,000 --> 00:06:00,667
Enceladus might actually look
a lot like early Earth in its
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00:06:00,767 --> 00:06:02,867
deepest oceans,
when life was first arising,
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00:06:02,867 --> 00:06:05,200
because we know that there are
some chemical pathways that are
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00:06:05,266 --> 00:06:08,000
likely occurring on Enceladus
that happened on Earth.
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00:06:12,266 --> 00:06:14,200
These chemical pathways
start with
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00:06:14,266 --> 00:06:16,867
hot, hydrothermal vents
on Earth's
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00:06:16,867 --> 00:06:21,600
cold sea floor, releasing
important life-giving chemicals
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into the oceans.
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00:06:24,367 --> 00:06:26,867
Having hydrothermal vents
are a real
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00:06:26,867 --> 00:06:29,166
boon to the evolution of life.
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00:06:29,266 --> 00:06:30,000
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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00:06:37,000 --> 00:06:38,467
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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00:06:42,166 --> 00:06:44,867
are able to just grab all
these resources and energy
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and just start
to evolve.
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00:06:47,667 --> 00:06:51,667
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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00:06:56,567 --> 00:06:59,600
living around the vents
makes the rest.
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00:07:03,600 --> 00:07:07,400
Maybe microorganisms
do the same
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00:07:07,467 --> 00:07:14,467
at the bottom of Enceladus's
deep oceans.
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00:07:14,467 --> 00:07:17,667
Hydrothermal vents on
Enceladus could offer
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the perfect location
for chemistry
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00:07:21,166 --> 00:07:24,166
becoming biochemistry
becoming life.
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00:07:26,467 --> 00:07:29,400
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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00:07:36,367 --> 00:07:40,900
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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00:07:48,867 --> 00:07:52,200
Cassini spotted
Enceladus's plumes
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00:07:52,266 --> 00:07:54,266
shooting out
from parallel cracks
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00:07:54,367 --> 00:07:57,467
in the surface,
called tiger stripes.
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00:08:02,500 --> 00:08:06,000
The cracks are a clue to
the origin of the geysers
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00:08:06,100 --> 00:08:08,066
and the energy that
powers them.
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00:08:11,000 --> 00:08:12,900
We look to the orbit of
Enceladus itself.
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00:08:13,000 --> 00:08:14,800
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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00:08:18,667 --> 00:08:22,467
the tidal forces acting on
the moon change over time.
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00:08:22,467 --> 00:08:25,567
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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00:08:34,667 --> 00:08:36,867
and deform and squish
the body of
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00:08:36,867 --> 00:08:39,767
that moon over time, which is
gonna heat its interior.
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00:08:43,767 --> 00:08:46,567
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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00:09:00,400 --> 00:09:02,667
We see the energy source
kicking the water
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00:09:02,767 --> 00:09:04,700
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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00:09:29,200 --> 00:09:30,000
but other moons
weren't as lucky.
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00:09:30,000 --> 00:09:31,300
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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00:10:06,166 --> 00:10:09,367
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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00:10:18,367 --> 00:10:22,066
To understand such
a marked difference in size,
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00:10:22,066 --> 00:10:26,000
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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00:10:47,967 --> 00:10:51,166
the ringless gas giant
grows from gas,
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00:10:51,266 --> 00:10:54,767
rock, and ice in
the protoplanetary disk,
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00:10:54,767 --> 00:10:56,867
along with a family
of moons.
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00:10:59,667 --> 00:11:03,367
This origin story works for
most of Saturn's moons,
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00:11:06,166 --> 00:11:09,467
but not for the recently
discovered objects orbiting
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00:11:09,467 --> 00:11:13,000
in the opposite direction of
the planet's rotation.
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00:11:14,266 --> 00:11:16,919
If there's a moon orbiting in
the other direction,
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00:11:16,919 --> 00:11:17,667
If there's a moon orbiting in
the other direction,
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00:11:17,667 --> 00:11:19,567
it couldn't have formed with
the planet.
199
00:11:20,667 --> 00:11:22,767
It must have come from
somewhere else.
200
00:11:24,200 --> 00:11:26,266
Saturn captured these moons.
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00:11:27,800 --> 00:11:29,300
But from where?
202
00:11:33,367 --> 00:11:35,700
We think there was a huge
upheaval in the solar system
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00:11:35,767 --> 00:11:37,100
over four billion years ago,
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00:11:37,166 --> 00:11:38,967
where the giant planets
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00:11:38,967 --> 00:11:42,166
went from a close and compact
configuration, started
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00:11:42,266 --> 00:11:43,867
having interactions
with each other,
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00:11:43,867 --> 00:11:46,467
moved each other around
to end up into the orbits
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00:11:46,467 --> 00:11:46,919
that they find today.
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00:11:46,919 --> 00:11:47,567
that they find today.
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00:11:47,567 --> 00:11:50,066
During that process, a lot of
smaller bodies,
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00:11:50,066 --> 00:11:51,567
like asteroids
from the distant part
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00:11:51,667 --> 00:11:53,000
of the solar system
got scattered
213
00:11:53,066 --> 00:11:54,967
every which direction.
214
00:11:56,600 --> 00:11:59,100
During
this ancient upheaval,
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00:11:59,166 --> 00:12:01,667
Saturn grabs some of
the scattered objects.
216
00:12:04,567 --> 00:12:08,000
Many bodies now crowd
the region around the planet,
217
00:12:09,567 --> 00:12:12,000
and that means collisions.
218
00:12:15,667 --> 00:12:16,919
Some are destructive.
219
00:12:16,919 --> 00:12:17,600
Some are destructive.
220
00:12:17,667 --> 00:12:19,900
Others form new moons.
221
00:12:21,367 --> 00:12:22,767
In the cosmic pinball,
222
00:12:22,867 --> 00:12:25,166
some moons are thrown
out of the system,
223
00:12:27,166 --> 00:12:29,567
and others,
into Saturn.
224
00:12:29,667 --> 00:12:32,767
Only one large moon
survives the carnage.
225
00:12:34,467 --> 00:12:35,900
And all of a sudden,
most of the mass
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00:12:36,000 --> 00:12:38,166
of all the satellites is in
that single moon, Titan.
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00:12:41,166 --> 00:12:44,400
Titan may have formed
from the material in
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00:12:44,467 --> 00:12:46,919
the protoplanetary disk at
the same time as Saturn,
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00:12:46,919 --> 00:12:48,166
the protoplanetary disk at
the same time as Saturn,
230
00:12:48,166 --> 00:12:52,467
but then gorged on the debris
created in the later
231
00:12:52,467 --> 00:12:57,500
lunar collisions.
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00:12:57,567 --> 00:13:03,200
It amassed 96 percent of
the material orbiting Saturn
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00:13:03,266 --> 00:13:06,800
and grew so large that it
developed a dense atmosphere.
234
00:13:11,166 --> 00:13:13,266
When Voyager
photographed Titan,
235
00:13:13,367 --> 00:13:15,967
it clearly showed that Titan
had a thick atmosphere,
236
00:13:15,967 --> 00:13:16,919
which was so
incredibly exciting,
237
00:13:16,919 --> 00:13:18,400
which was so
incredibly exciting,
238
00:13:18,467 --> 00:13:20,300
but it was so dense
and impenetrable,
239
00:13:20,367 --> 00:13:22,900
that was all we could see.
240
00:13:24,467 --> 00:13:26,567
Two decades after Voyager,
241
00:13:26,667 --> 00:13:29,400
the Huygens Probe
launched from Cassini
242
00:13:30,867 --> 00:13:34,800
and plunged through the murky
depths of Titan's atmosphere.
243
00:13:40,967 --> 00:13:42,667
Our first images of what
244
00:13:42,767 --> 00:13:45,166
the Titanic landscape was like
245
00:13:45,266 --> 00:13:46,919
were utterly and truly
mind-blowing.
246
00:13:46,919 --> 00:13:50,300
were utterly and truly
mind-blowing.
247
00:13:50,367 --> 00:13:51,700
It showed there were mountains
248
00:13:51,767 --> 00:13:52,767
and there was
sort of erosion
249
00:13:52,867 --> 00:13:54,767
on those mountains
that looked like liquid
250
00:13:54,767 --> 00:13:57,900
had fallen down the mountains
and brought material with it.
251
00:13:59,266 --> 00:14:01,367
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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