How the Universe Works - S03E05 - Is Saturn Alive
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00:00Dazzling, legendary, the most beautiful planet in the night sky, but secretive Saturn has
00:09been holding out on us.
00:11We've learned a vast amount about it, and most of this has been very surprising.
00:16We thought we knew those bodies.
00:18We had no idea.
00:21Saturn boils with extreme weather and weird lights.
00:25The rings ripple and twist, bullied by over 60 remarkable moons.
00:31They are individual worlds, they each have a story to tell.
00:35This is a planetary explorer's dream.
00:38Saturn's moons are the hottest property in the search for alien life.
00:42If there's one place in the solar system I would put a bet that life exists there right
00:47now, I would choose Saturn.
00:49And on Saturn's largest moon, we may have already found it.
00:53We have found some curious things on Titan, and it might just be evidence of life.
01:03Saturn, the jewel of the night sky, dazzles with its beauty and scale.
01:22It's huge, so big you could fit more than 700 Earths inside it.
01:29But don't let size fool you.
01:33One of the more interesting things about Saturn is that it is so big compared to how much
01:37stuff is in it, that it's actually lower density than water.
01:42The old joke is that if you could find a bathtub big enough and fill it with water, Saturn
01:46would float, but it would leave a ring.
01:49Other planets have rings, but none so vast and glorious as Saturn's.
01:55The journey from the outside of the main rings to the inside edge is 66,000 miles.
02:04Yet this vast collection of dust and ice particles is whisper-thin, just tens of feet in places.
02:13Saturn's rings are made up of mostly very small particles of ice and rock.
02:17Some of the particles are larger, but for the most part, no bigger than grains of dust.
02:23Racing within the rings and orbiting far outside them are over 60 moons made from rock and
02:30water ice.
02:33They range in size from tiny snowballs to worlds with active geology, liquid water,
02:43weather systems, and possibly even life a billion miles from the warmth of the sun.
02:50It's so cold out there, we just thought there'd be nothing there, and we were so wrong.
02:55We were so wrong.
03:01Saturn's first shocker, its wild weather.
03:09The storms on Saturn are extremely violent.
03:12Unlike anything we see on the planet Earth.
03:14In fact, Saturn has the second fastest winds in the entire solar system.
03:21These winds race through Saturn's cloud tops at over 1,000 miles per hour, four times faster
03:29than Earth's strongest cyclones.
03:32And lightning bolts flash up to 10,000 times more powerfully than those on Earth.
03:41Everything on Saturn is just so very, very much bigger.
03:43I mean, there are weather systems that are as big or bigger than the Earth.
03:49Saturn's ferocious weather is surprising, because on Earth, weather is driven by the
03:54heat of the sun.
04:00It causes the seas to evaporate, creating clouds and rain.
04:06Nothing lies too far from the sun to feel the same warmth, so the heat that drives its
04:12weather must be coming from somewhere else.
04:17To understand this mysterious heat source, we need to go back four and a half billion
04:22years to the birth of the ringed planet.
04:32The planets of our solar system emerged from a vast, swirling cloud of ice, dust, and gas.
04:41The same ingredients can still be found on Earth today, in places like Iceland, where
04:48volcanic ash mixes with icy glaciers.
04:51So if you want to build a giant planet like Saturn, this pile of raw material here is
04:57a great visual analog.
04:59There's a lot of oxygen and hydrogen in the universe.
05:02That makes water.
05:03That makes water ice.
05:04And the stuff initially that made the solar system is basically this stuff here.
05:07It's dirty ice, water ice, with a little bit of rocky and metallic minerals left in there
05:12out there in the cold of space.
05:16Four and a half billion years ago, a vast cloud of dirty ice particles, shrouded in
05:23oxygen, hydrogen, and helium, collapses under its own gravity.
05:28And at the center, a new star, our sun, sparks into life.
05:34The heat of the new star melts the ice closest to it and blows away the gas, leaving only
05:41rocky debris behind.
05:43But farther out, icy material and gas survive.
05:48A boundary forms, a frost line between the rocky inner cloud and the icy gas beyond.
05:57Once you've fired up that campfire, if you will, what will be left behind in the inner
06:00solar system is going to be this stuff, the silicate minerals you make a planet like the
06:04Earth from.
06:05But far away from the sun, where it's colder, you cross the frost line, and what's out there
06:11is still cold enough to maintain the ice behind, and there's a lot of it there.
06:17At first you make a sort of a solid core of this material, but when you reach a critical
06:21mass, you've got enough gravitational influence to start to directly draw in some of the hydrogen
06:26and helium in the interplanetary cloud.
06:29Saturn's huge solid core, now 10 to 20 times the size of Earth, generates relentless gravity
06:40and draws in gas.
06:42The bigger this gas ball gets, the more material it sucks in.
06:48Saturn's massive gravity then gets to work on its fledgling atmosphere, compressing it,
06:55and like any gas under pressure, it gets seriously hot.
07:01Even today, Saturn's high-pressure atmosphere heats its core to 21,000 degrees, twice the
07:09temperature of the surface of the sun.
07:14And it's this heat rising up which forms Saturn's distinctive bands and drives its extreme weather.
07:22Saturn's actually rotating very quickly.
07:24It's a large planet, it rotates once on its axis about every 10 hours.
07:29So as the weather comes up from the interior, it gets smeared out into bands.
07:36And at Saturn's North Pole, the bands do something that at first glance seems impossible.
07:43There is a gigantic vortex, a spinning region of air that's shaped like a perfect hexagon.
07:51You have waves of pressure, density, and temperature that start to interact with each other.
07:56And these waves can actually interfere and become one big wave that goes all the way
08:00around the planet.
08:02This giant wave settles into a long-lasting pattern because there's no rocky surface below
08:08to disrupt the winds that form it.
08:11They form a beautifully defined regular hexagon.
08:14It's one of the most spectacular things about Saturn.
08:18It took robotic probes to reveal the weird weather on Saturn.
08:24But if these close-up shots of storms and lightning took scientists by surprise, they
08:30were nothing compared to the shock of what came next.
08:35The rings are alive.
08:50Imagine Saturn without its rings, just a pale globe floating in the darkness of space.
09:00With the rings, it's magical.
09:08Undoubtedly the one thing that captures everyone about Saturn is the rings.
09:11It's inspired fiction stories, and it's inspired everyone who's looked at it in the night sky.
09:18When I was four or five years old, my parents bought a small department store telescope.
09:21And I remember looking down into that eyepiece and seeing this perfect jewel of a planet.
09:29There's just nothing better than this.
09:31And you can just see the rings going around the planet just perfectly.
09:34They're just a gorgeous elliptical racetrack.
09:39From the eyepiece of a small telescope, the rings seem quiet and serene.
09:45But up close, it's a very different picture.
09:48We know this thanks to a space probe called Cassini and over 10 years of images like these.
09:59Ice particles jostle for position like stock cars, traveling inside the rings at hundreds
10:05of thousands of miles per hour.
10:09These particles range in size from chunks of ice as big as houses to the finest powder
10:15snow.
10:17It wasn't until we went to Saturn and stayed there with Cassini that we learned just how
10:22fiercely complex it is.
10:24You have the gravity of the planet itself and all of these moons interacting with the
10:28rings and the moons and the planet.
10:31All of these things are sculpting that entire system on scales that are both subtle and
10:36gross and it makes this magnificent crown jewel of the solar system.
10:43As small moons go around inside, the ring particles dance around them in response.
10:48We see areas of the rings that get raised up as a moon goes by.
10:52Moons will even switch orbits with each other.
10:54So there's a lot of dynamic stuff going on inside the rings.
10:59Scientists believe that from time to time Saturn's icy moons break up, adding new material
11:06to the rings.
11:08This means that the structure of the rings is constantly evolving.
11:14With Cassini, scientists can deconstruct the physics of this evolution and it's teaching
11:20us the rules that make the whole universe tick.
11:27All the planets in our solar system evolved out of the same flat disk of dust and gas
11:334.5 billion years ago.
11:38Astronomers see similar disks around young, distant stars.
11:42But even with our most powerful telescopes, we can't see planets forming.
11:47They're too far away.
11:50Saturn's rings are right on our doorstep, a veritable snapshot of a mini-solar system
11:56caught in the process of formation.
12:00Looking at the rings, we're looking at the formation of planets or bodies in an arrested
12:06state of development.
12:07It's like you took the beginning stages of the formation of the planets but stopped it.
12:16Cassini shows structures forming spontaneously inside the rings.
12:21They don't even need to be tickled, they don't need to be disturbed into forming structures,
12:27they form them on their own.
12:29Does this tiny moon, captured in the process of formation, show us how the Earth started
12:35its life?
12:37You get something that just happens to form out of random processes and that mimics what
12:44astronomers think they're seeing in proto-planetary disks surrounding other stars in the cosmos
12:50around us.
12:53Cassini sees curious propeller-like structures inside Saturn's broad A-ring.
12:59They're caused by ring particles washing over tiny, hidden moons.
13:06The particles collide with the moons, sending them into random, ever-changing orbits, sometimes
13:13closer to Saturn and sometimes farther away.
13:20Perhaps similar forces influence the Earth's formation around the Sun, pushing it into
13:26closer or wider orbits.
13:34Saturn's rings also help us understand why planets stop growing.
13:40A walnut-shaped moon called Pan sits near the middle of Saturn's A-ring.
13:46Pan should be huge, with so much ice around to gobble up, but it's tiny, only 20 miles
13:53in diameter.
13:55If you have a moon embedded in a disk of ring particles, you might naively think it just
14:00secretes ring particles until it grows into a, you know, a bigger moon.
14:05But actually, we find moons create gaps in the ring around them, so Pan has created the
14:11Encke gap, Daphnis has created the Keeler gap.
14:15Rather than pulling ring material in, Pan appears to push it away.
14:21As the moon passes the slower-moving material outside it, Pan's gravity slings the particles
14:28into wider orbits.
14:30The faster material inside Pan's orbit is slowed as it passes the little moon, causing
14:37it to fall away towards Saturn.
14:41This may explain why multiple planets form around stars, instead of single giant planets
14:48that eat the whole buffet.
14:53Of all Cassini's discoveries, the most important is also the most surprising, a tiny ice moon
15:02that may be home to life.
15:18For most of history, the only moon we've been able to study up close is our own.
15:25Multiple deep craters tell a powerful story.
15:29The moon is dead.
15:30There's no active geology or weather to wipe away these ancient scars.
15:37But what about the moons around other planets, like Saturn?
15:41Are they dead too?
15:44Our first assumption about Saturn was that the moons would be like that, cold, dead,
15:48lifeless relics from the early solar system.
15:50It wasn't until we invented spacecraft that could go to these moons that we discovered
15:56how incredibly diverse our solar system truly is.
16:06Take Enceladus, an icy moon barely 300 miles across.
16:12Nobody paid it any attention a decade ago.
16:17Today, it's a geological rock star.
16:21And this is why.
16:24Enceladus orbits inside Saturn's outermost ring, the E-ring.
16:30The E-ring puzzled scientists because they couldn't figure out how a ring so broad and
16:36so diffuse could hold itself together.
16:40The Cassini team decided to take a close flyby of Enceladus to solve the mystery.
16:47Did it have something to do with keeping the particles together?
16:53What was the connection between the E-ring and Enceladus?
16:57Well now we know that Enceladus is actually responsible for the E-ring being there in
17:01the first place.
17:042005, Cassini captures an astonishing sight, a hundred geysers shooting ice particles miles
17:13into space from cracks in the South Pole.
17:18Enceladus is hurling its guts into space at a colossal rate.
17:23As Enceladus orbits Saturn, these icy plumes feed a vast, shimmering halo around the planet,
17:31the mysterious E-ring.
17:36This icy plume also interacts with Saturn's magnetic field, creating a plasma cloud of
17:43charged particles.
17:49The particles race along Saturn's magnetic field lines and slam into Saturn's polar
17:55atmosphere, raising huge ultraviolet auroras.
18:02Geysers, explained the E-ring, but how can they exist on a frozen moon a billion miles
18:08from the Sun?
18:14On Earth, geysers form in highly volcanic places where water comes into contact with
18:20hot rocks.
18:22Enceladus, so small and so far from the Sun, should be cold and dead.
18:28What heats it is Saturn's gravity.
18:36The source of the heating on Enceladus is the eccentric orbit of that moon.
18:41Sometimes it's a little closer to Saturn, sometimes it's a little further away.
18:45And that heating on Enceladus from that kneading gravitationally making the moon stretch and
18:50pull is what warms the interior, causing the activity on Enceladus that we see today.
18:59The gravitational pull of Saturn reaches deep into Enceladus, beyond its water ice exterior,
19:06gripping its rocky core.
19:11As Saturn's grasp strengthens and weakens, it massages this cold rocky heart, bringing
19:18it to geological life with frictional heat.
19:23The heat melts the ice around it, creating a vast subsurface lake.
19:30This water jets out through huge cracks in the surface ice.
19:35On Earth, where there's liquid water, there's life.
19:39Could Enceladus have what it takes for simple organisms to exist?
19:46Once Cassini saw these geysers, the scientists knew they had found something extremely wonderful.
19:51They actually changed the mission of Cassini itself, changed its trajectory.
19:56We sent the Cassini spacecraft to fly very, very close over these cracks where the water
20:00was rushing out.
20:04Scientists clung to the faint hope that the water would contain salts and organic molecules
20:09like ammonia, the building blocks of life here on Earth.
20:15Stunningly, Cassini's sensors tasted them all in abundance.
20:22In that plume, there's organic material.
20:25It's not water, it's a soup.
20:27That's incredible.
20:29All the main requirements for habitability, energy source, liquid water, source of biological
20:35nitrogen and ammonia, organic material, and the samples are coming up into space.
20:40There's a big sign, free samples, take one.
20:42There could be life that could have evolved there.
20:45Now we don't know.
20:46We haven't seen it.
20:47But the conditions there are as good there now as they were on Earth three billion years
20:53ago when life arose here.
20:56The sensational realization that Enceladus may harbor life has sparked intense debate
21:02about future missions to find it.
21:05But it has a rival for those precious research dollars, because Saturn's largest moon, Titan,
21:12could also be home to life, bizarre life, and we may have already found it.
21:30More than 60 moons orbit the planet Saturn, but one dwarfs them all.
21:37Titan is a colossus, bigger than the planet Mercury.
21:42A thick orange haze hides its surface from our telescopes.
21:47And when the Cassini mission first peered beneath Titan's orange cloak, it revealed
21:53a world weirder than we could have ever imagined.
21:58Titan is an amazing place, and of all the things going on around Saturn, Titan might
22:03be the most exciting of all.
22:08Titan has mountains and deserts, rivers and lakes.
22:13Only the Earth can match it for geological diversity.
22:17But here, water ice takes the place of bedrock, frozen at 300 degrees below zero.
22:26Instead of water, the rivers on Titan flow with methane.
22:31This is a place where it actually rains liquid methane, liquid natural gas.
22:36This liquid is filling up rivers and lakes.
22:40This makes Titan incredibly special.
22:42It's only the second world in the solar system where we know there's liquid on the surface.
22:52Unlike Earth, Titan has a thick, nitrogen-rich atmosphere.
22:56But instead of the oxygen we breathe, Titan's air is spiked with carbon-rich molecules that
23:03stain it a dull orange.
23:06It's a soup of methane and ethane and propane and acetylene.
23:11The list of organic molecules is literally hundreds, hundreds long that we've detected
23:15there.
23:19Titan's complex cocktail of atmospheric chemicals intrigues scientists.
23:24But it also puzzles them.
23:26Especially methane gas, which rapidly decays in sunlight.
23:32So even a billion miles from the sun, Titan's thick haze should have lifted long ago.
23:39A vast source of methane must be replenishing the orange smog.
23:45For Cassini, scientists assumed the whole of Titan was covered in massive impact craters.
23:53Perhaps crater lakes filled with liquid methane were evaporating into the atmosphere, supplying
23:59the missing gas.
24:02Cassini carried a hitchhiker all the way to Saturn to help prove this theory.
24:12The Huygens Lander parachuted through the clouds, snapping photographs as it fell.
24:20As it went through the atmosphere, it took a huge amount of data and then landed on the
24:25moon itself and took pictures.
24:27When we first saw those pictures, it was life-changing.
24:33There were no craters.
24:35It looked like flowing liquid had once shaped the landscape.
24:39But at the landing site, and as far as Huygens could see, that liquid was long gone.
24:48Huygens landed in a spot almost identical to what we're standing on right now.
24:54If we look all around, we can see this bleak, barren landscape.
24:58We see pebbles and cobbles that have been rounded and smooth because they've come through
25:02river channels.
25:03We see plenty of those at the Huygens landing site.
25:06In addition to that, we see lots of sand.
25:10The desert Huygens landed in is huge.
25:15It stretches all the way around Titan's equator, with 300-foot-tall dunes sculpted by the wind
25:25just like they are on Earth.
25:29If the vast crater lakes weren't at the equator, they had to be at Titan's poles.
25:36Cassini scheduled a number of additional flybys to look for any signs of liquid.
25:43One of the instruments on board Cassini is basically a radar gun.
25:46It shoots radar waves at Titan, and they get reflected back.
25:51After two years of hunting, scientists finally got the signal they were waiting for.
25:57One of the things it found is that near the north pole of Titan were regions that were
26:01not reflecting radar.
26:03And that sounds a lot like liquid.
26:05Liquid absorbs that energy and doesn't reflect it back.
26:10Later observations clinched it.
26:12When Cassini finally imaged the north polar regions of Titan, it finally saw these lakes
26:17and seas of methane that we'd been looking for, only they weren't contained in impact
26:21craters like we thought.
26:22Instead, they're contained in big lake basins that look just like they do on Earth.
26:32Moon lakes, like this one in Mono County, California, form in the depressions left from
26:38tectonic activity.
26:41These geological features on Titan could only mean one shocking thing.
26:46The moon was alive with geological activity.
26:49If we were sitting on the margins of Kraken Mare, which is the largest sea that we see
26:56on Titan, then we would probably see something very similar to this landscape.
27:00We would look out across a fairly calm surface.
27:03We think the winds are not very strong on Titan, and so we'd have this calm lake of
27:08methane and ethane.
27:09And in the distance, we would see hills and mountains that have formed on Titan, probably
27:13through tectonic processes in much the same way that mountains are built on Earth.
27:18Except on Titan, it's so cold that volcanoes spew water, not lava.
27:25The mountains and lake basins are solid ice.
27:33At first, scientists thought that methane evaporating from these lakes generated Titan
27:38smog.
27:40But when Cassini flew by to measure the lakes again, the levels appeared to be the same.
27:46The lakes didn't look like they were evaporating at all.
27:51Scientists were stumped.
27:52Either the lakes weren't the source of the atmospheric methane, or they were somehow
27:56being refilled.
28:01Planetary geologist Janie Radabaugh believes a crucial clue to the missing methane lies
28:07in the formation of rocky deposits called tufa.
28:12They're found here at Mono Lake, where clean spring water rises up from the ground into
28:18the mineral-rich lake, and the two water types react.
28:24This is very exciting, because this could be a clue to the missing methane on Titan.
28:33So it's rock that has been formed from the chemicals contained in two fluids.
28:37There is water that's emerging at the margin of the lake.
28:41It's interacting with the lake water, which has a very different chemistry, and all of
28:45the chemicals that are dissolved combine with each other and create this rock.
28:50Radar images of Titan's largest lake reveal rocky structures around the margins that look
28:56just like Mono Lake's tufa.
28:59Titan's tufa, if that's what they are, could be evidence of a layer of liquid methane that
29:05sits above Titan's frozen core and rises in springs to feed its lakes, just like spring
29:13water rises to feed Mono Lake.
29:17So when those methane springs come in, they interact with the lakes, and rock precipitates
29:22out.
29:23So we see these organic rocks dotting the margins of the lakes, and almost certainly
29:29there's also methane just bubbling up and emerging at the margins of the lake as well.
29:34If Janie is right, Titan's lakes do evaporate, feeding the atmospheric smog, but they're
29:41constantly replenished by underground methane springs replacing the lost fluid.
29:53Titan is no dead world.
29:55It's alive with active geology and complex chemistry.
30:01And it might be alive with something else, something big.
30:11We used to think that Saturn was too far from the sun and too cold to play host to
30:26anything dramatic.
30:28We couldn't have been more wrong.
30:32The planet boils and bangs with active weather, storms, lightning, and auroras.
30:40The rings constantly evolve.
30:46And the moons aren't the frozen snowballs we expected.
30:51They're shaped by active geology, with warm water geysers, and lakes of liquid methane.
31:01And now, on Saturn's largest moon, Titan, scientists may have uncovered the first tangible
31:08evidence of extraterrestrial life.
31:15Our search for life has been focused on liquid water.
31:18Follow the water.
31:19I think it's a good strategy.
31:21But I think we are limiting ourselves if we think that that's the only place to look.
31:25I think liquids may be interesting, even if they're not water.
31:34Scientist Chris McKay believes that life on Titan may have evolved to live in liquid
31:39methane, not liquid water.
31:42But Titan's so cold, simple life would play by a different set of rules, where bigger
31:49is better.
31:50When we go to other worlds, we're going to be looking for bacteria, and we assume that
31:55they're going to be very small.
31:56But you could ask the question, why are bacteria so small?
32:00Well, I think the answer is because they live in water.
32:05On Earth, bacteria don't need to grow big to thrive.
32:11Water dissolves almost everything, so it provides a nutrient-rich environment where small and
32:18simple brings success.
32:19We go to Titan, where the liquid is liquid methane, liquid ethane, very different from
32:25water.
32:26There's no reason an organism should be small.
32:28In fact, quite the opposite.
32:29It should be huge.
32:30McKay envisions enormous single-celled organisms looking like sheets of paper.
32:38Their huge surface area would maximize the uptake of food from the nutrient-poor liquid
32:45methane.
32:46I predict that there's life on Titan living in liquid methane.
32:50You won't need a microscope to see it.
32:52You'll need a yardstick.
32:57When Cassini released the Huygens probe high above the cloud tops of Titan, McKay realized
33:04he had an opportunity to bolster his theories of life on the surface.
33:10His methane-loving lifeforms must be eating to survive.
33:14Perhaps Huygens' delicate sensors would pick up evidence of ground-level feasting.
33:22As Huygens was on its way to Titan, I'm sitting in a hotel room writing up a paper
33:27saying, hey, what if there's life on Titan?
33:30What would it eat, and how would we detect it?
33:32How would this probe flying through the atmosphere detect it?
33:36Literally the day Huygens landed, I submitted this paper to the journal, predicting that
33:42if there was life on Titan, it would eat hydrogen, and the probe would be able to measure this
33:47depletion in hydrogen.
33:49So let's look for hydrogen.
33:52Huygens parachutes through Titan's atmosphere, sampling the gases as it goes.
33:58The upper atmosphere has plenty of hydrogen.
34:01So do the middle layers.
34:04But at the ground level, there's a surprise result, an apparent drop-off in the concentration
34:11of hydrogen in the air.
34:13Something, or perhaps someone, was using it up.
34:19When I heard a report that there was a depletion of hydrogen, my heart raced, because I thought,
34:27if this is hard data for depletion of hydrogen, I can't imagine any other way besides biology
34:32to explain that.
34:35It's exciting in that it's consistent with what we predicted, but we have to wait for
34:40this to be confirmed by other calculations, by direct measurements, and so on.
34:47If future missions can confirm methane-based life on Titan, it will surely be the greatest
34:54discovery in the history of science, because this low-temperature biology must have arisen
35:01independently of life on Earth.
35:07If we discover life, let's say, on Mars, there will always be the possibility that rocks
35:13and ice and bits of material could have been exchanged, but the chances of that happening
35:17from Earth all the way to Saturn are next to nothing.
35:21If we find a second example of life in our solar system, especially in a place like Titan,
35:27which is so alien to the Earth, so cold and so different, that tells us something excruciatingly
35:33important, and that is that life must be everywhere in the universe.
35:44Robotic missions offer tantalizing hints of simple life on Enceladus and Titan.
35:52But is Saturn's realm only fit for giant bacteria, or is it a place we humans could one day call
36:00home?
36:13Saturn orbits a billion miles from the Sun, so far out that it takes an hour for its reflective
36:24light to reach our eyes.
36:27Yet the future of our civilization may rest on humans one day colonizing the moons surrounding
36:34this gas giant planet.
36:37It won't be easy, but Saturn has something worth the trouble, a magical source of fuel
36:44called Helium-3 that could satisfy our increasing hunger for energy for millions of years.
36:54Some futurists believe that we have to have a commercial incentive to going to Saturn,
37:00not just to mine the minerals of the moons of Saturn, but also to harvest fuel in the
37:05form of Helium-3.
37:09Helium-3 is a rare substance that we could use in fusion engines to provide perhaps unlimited
37:15energy.
37:19Helium-3 is uniquely suited to a form of energy production called fusion, the same process
37:28that burns in the heart of a star.
37:34When two nuclei are crushed together under enormous pressure, they fuse, creating a new
37:41heavier atom and a burst of pure energy.
37:47Best of all, Helium-3 doesn't release any of the harmful radiation associated with other
37:54fusion fuels.
37:57The only trouble with Helium-3 is that there's precious little to be found on Earth.
38:05Now you can find some Helium-3 on the moon, but the major supplies of Helium-3 in our
38:10solar system are located in the atmospheres of the giant planets.
38:15I call the gas giants the Persian Gulf of the solar system because they are the location
38:19of its primary energy resources outside of the sun.
38:25The gas giants provide a near inexhaustible supply of Helium-3, but how could we extract
38:31it?
38:33Jupiter has the most, but the planet's immense gravity and dangerous radiation belts make
38:39it a no-go for mining.
38:43Neptune and Uranus are way too far away to be practical.
38:48That leaves Saturn, with relatively low gravity for such a big planet and far lower levels
38:55of deadly radiation than around Jupiter.
39:00If we're going to have a future human economy based on using controlled fusion and Helium-3,
39:05Saturn is the destination of choice.
39:10Futurists envision winged drones flying through the upper atmosphere of Saturn, scooping up
39:15gases.
39:19But where to process this super-fuel?
39:22The ideal base of operations would clearly be Titan.
39:29With gravity as gentle as our moons and a thick, Earth-like atmosphere, Titan is surprisingly
39:37suitable for a human outpost.
39:41We could have huge dome settlements on Titan.
39:43They would not have to be strong enough to hold pressure.
39:45They could just be thin, inflatable membranes.
39:48You could have dome cities like you see in science fiction, which are really not possible
39:52in places like the moon.
39:53Walking out onto the surface of Titan would be much easier than on the moon or on Mars.
40:00The pressure on Titan is kind of nice.
40:02It's one and a half times Earth pressure.
40:05You would need a source of oxygen, and you need a very warm coat.
40:09But it wouldn't feel as cold as you might think because the atmosphere is calm and there's
40:16not strong wind.
40:18I think a coat like you might wear in Antarctica might be adequate.
40:22So you can imagine somebody stepping out of a spaceship, having a parka on, a mask like
40:27a scuba mask to provide oxygen, and literally walking out on the surface.
40:32Titan's low gravity and dense atmosphere could even send us soaring from place to place.
40:41Let's say you had, you know, it's a little bit of a wing on your arm, and you started
40:44to flap your arms.
40:45Remember, it's almost like you're on the moon, but with a thick atmosphere, and you'd really
40:49be able to lift yourself off the surface, maybe fly just a little bit.
40:58When the Helium-3 trade route has opened and the Earth becomes a fusion economy, a new
41:05generation of rockets will open up interplanetary travel to everyone, taking humans to Mars
41:13and Jupiter in months, not years.
41:17And Helium-3 might even power adventure tourism to Saturn itself.
41:25You can imagine in a hundred years when space travel is easy and there will be hotels orbiting
41:29the moon and Mars and everything, what would be the one, what would be the place, right,
41:33to go?
41:34It would be Saturn.
41:41I would hope one day that there is such a thing as space tourism and people can visit
41:46places like Enceladus.
41:48This should be called the Enceladus Interplanetary Geyser Park because it would be a phenomenal
41:53place to just go visit.
41:58Standing on Enceladus would be an amazing sight.
42:00All of this frost condensing back out on the surface makes an incredibly brilliant white.
42:05It's got some of the best powder snow for skiing anywhere in the solar system.
42:14You could get close enough to actually see the individual rings, maybe even see the little
42:19moons in the gaps sculpting and pulling and pushing and prodding, shepherding those ring
42:24particles around.
42:25You could go back over and over again and it would always be alien and exotic and exciting.
42:36From a cold, dead jewel in our telescopes to a place alive with magic and mayhem, Saturn
42:44and its worlds have come alive and may harbor life itself.
42:51Someday soon, this planet could remake our universe and nothing will ever be the same.