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00:00Our solar system is a savage place. From the ice volcanoes of Saturn's moon Enceladus,
00:12to the vast lava fields of Jupiter's Io, to our own world, the Earth. Volcanoes destroy,
00:20they also create.
00:22It's literally true that if there weren't volcanoes here, we would not be here either.
00:27Volcanoes shape and change our climate.
00:30Volcanoes are the giver of life and also the takers of life.
00:35Today's space probes and telescopes reveal volcanoes on worlds we once thought dead.
00:43Finding volcanoes on an object that's smaller than our own moon was a huge shock.
00:50If volcanoes exist on other worlds, could we find life there too?
01:17Dark Earth, a jewel in the darkness of space.
01:23Our home is timeless, beautiful, and incredibly violent.
01:34Volcanoes are one of the most powerful natural phenomena on the planet.
01:39They create new land, destroy the old.
01:45They blast out gases that transform the air we breathe.
01:52Deep in our oceans, volcanic heat fuels strange new life.
01:59Volcanoes help power the living Earth.
02:05Now we search for signs of life on alien worlds.
02:11We know life needs water. We know it needs energy.
02:16And that's where volcanoes come in.
02:19They pump out vast amounts of energy.
02:23Find volcanoes on other worlds, and we might find life.
02:41The search starts here.
02:44The planet orbiting closest to Earth, Venus.
02:48A world that appears very much like ours.
02:56Venus and Earth are roughly the same mass.
02:58They're roughly the same distance away from the sun.
03:00So they're kind of like twins.
03:07Three billion years ago, Earth and Venus were very similar.
03:14New land, new oceans, an atmosphere.
03:19Both planets were perfect for life.
03:25But on Venus, something went wrong.
03:34Something made Venus diverge radically from the history of the Earth.
03:38Venus took a definite turn to the dark side a long time ago.
03:41Venus is a hellhole.
03:44Our evil twin.
03:48Today, Venus' surface is like a furnace.
03:54It's 900 degrees Fahrenheit on the surface.
03:57And it's hot enough to melt, actually, some metals.
03:59So you wouldn't stand a chance.
04:02Venus is a greenhouse world.
04:05Its atmosphere is thick with carbon dioxide.
04:13It traps heat from the sun like a blanket.
04:18These actual images of Venus' surface reveal a barren, superheated wasteland.
04:28Venus' thick blanket of CO2 killed the planet.
04:38The CO2 came from volcanoes.
04:46Orbiting space probes gave the first clues.
04:52Radar punched through Venus' thick clouds.
04:58And revealed volcanic formations across the planet.
05:10Like formations we also see right here on Earth.
05:14The Schill Volcanoes of Hawaii.
05:20The Schill Volcanoes get their name from their round, flat shape.
05:28These volcanoes ooze.
05:32But they ooze for thousands of years.
05:38Once we were able to map the entire surface of Venus using cloud-penetrating radar,
05:42we started to study the landforms there.
05:44And we saw a lot that was actually very familiar.
05:47We saw giant Schill Volcanoes that are very similar to the Schill Volcanoes here in Hawaii.
05:53The radar images of Venus were dead ringers for the Schill Volcanoes on Hawaii.
06:00Sometime in the past, Venus had volcanoes.
06:07For the first time, we had a picture of Venus revealed.
06:12And boy, were we shocked.
06:15We found a scarred surface, a volcanic surface.
06:20There are at least a thousand volcanoes that are very large.
06:24And maybe tens or even hundreds of thousands of smaller ones.
06:30Three quarters of Venus' surface is lava plains.
06:35Evidence of an ancient cataclysm.
06:39This could have been a home for life.
06:43Instead, it was engulfed by fire.
06:47Volcanoes belched trillions of tons of carbon dioxide into Venus' atmosphere.
06:57Temperatures soared.
06:59The seas boiled dry.
07:01A runaway greenhouse process began.
07:05On Earth, carbon dioxide is able to absorb into the rocks.
07:08It's able to absorb into the ocean.
07:10But on Venus, you have no water.
07:12And it's now so hot that carbon dioxide can't even combine with the rocks.
07:16So, as carbon dioxide was released into the atmosphere by volcanoes a long time ago,
07:22over time, there was less and less of a method to take it back out of the atmosphere.
07:31If Venus ever had life, volcanoes sterilized the entire world.
07:43Earth remains the only living world we know of.
07:48That may change.
07:51This is the gas giant Jupiter, its moons frozen and dead.
07:59Or so we thought.
08:02Look closer, and a mystery emerges.
08:09A cloud hanging over a cold and lifeless world.
08:30On Venus, volcanoes turned an Earth-like world into a super-heated hell.
08:39Finding volcanoes on an Earth-like world was no surprise.
08:45But spotting volcanoes on the moon was a shock.
08:52In March 1979, the Voyager 1 space probe gave us our first close-up view of Jupiter's tiny moon, Io.
09:03A world we once thought cold and dead.
09:10And they saw something really weird.
09:12They saw this arc next to the moon.
09:15And it looked almost as if, like, there was another moon behind it.
09:18And we scratched our heads and said, well, what could that be?
09:21Everybody knows that Io is dead, boring, uninteresting.
09:26And then people realize, oh, my God.
09:29It's a volcanic eruption.
09:32We found that it's covered with volcanoes.
09:35It is tremendously geologically active.
09:37There are volcanoes erupting all the time.
09:40And what they're erupting is a lot of sulfur, and it gets very hot.
09:44And sulfur, when it changes temperature, changes color.
09:46It can be red or orange or yellow or black.
09:49And so these pictures of the face of Io make it look like a pizza covered with different kinds of cheese and olives where the little black spots are.
09:57Io is not dead.
10:00It's alive and kicking.
10:04It has over 400 active volcanoes.
10:11The largest, Pele, erupts from a gigantic lava lake.
10:19It reaches nearly 250 miles into space.
10:25If we could stand on the edge of that lava lake and watch that plume shooting off into the blackness of space, that would be an incredible sight.
10:40Pele's eruptions are so huge because Io is so small.
10:46There's nothing to hold the lava back, virtually no atmosphere, and very little gravity.
10:56These vast eruptions make Earth volcanoes look like firecrackers.
11:07How can such a tiny moon be so volcanic?
11:11The answer is Jupiter.
11:15Just as the moon raises tides in Earth's oceans, Jupiter raises tides on Io, tides of solid rock.
11:29Io's orbit around Jupiter is not a circle.
11:33Sometimes it's closer, sometimes farther away.
11:38Jupiter gives Io a gravitational pounding.
11:43And so Jupiter's gravity pulls on it a little bit harder and a little bit weaker.
11:47And what happens is the moon stretches like this.
11:50It's called a tidal force.
11:52It doesn't stretch this much.
11:53It's only a little bit.
11:54But in fact, it's enough to heat it up.
11:57It's just friction.
11:58It's the same way when you rub your hands together really fast, they begin to feel warm.
12:01Friction creates heat.
12:04Jupiter's gravity stretches and squeezes Io.
12:08Every two-day orbit, the ground rises and falls by nearly 300 feet.
12:17This pummeling generates intense heat and gigantic pressure.
12:26Wherever there's a weak part in the crust, the lava rushes out.
12:29So the volcanism is on a planetary scale.
12:32Unlike here on Earth, where there are certain bits that are active around the plates or in weak spots,
12:37this is an entire moon that's one active hot spot.
12:42Thanks to the incredible power of gravity, Io is the most volcanically active world in the solar system.
12:50The volcanism on Io taught us something new.
12:53It taught us that internal sources of energy can drive volcanism in a way that's different from that on Earth.
13:01In outer space, tidal forces, the differential squeezing of the moons of a gas giant, can also create volcanic activity.
13:11That was a game-changer.
13:18Io is a lava world, superheated and violent.
13:23It's hard to imagine anything surviving there.
13:29Yet the volcanic principle here is the same as on Earth.
13:35Pressurized, superheated magma below the surface blasts through fissures in the crust.
13:42But not all volcanoes need magma.
13:47They don't even need to be hot.
13:59Travel out past Jupiter into the outer solar system and it gets cold.
14:06Really cold.
14:10The distant moon Triton is so cold that much of its tenuous atmosphere can freeze solid.
14:19Yet there are volcanoes here.
14:23Volcanoes that may hold the secret of alien life.
14:42We think of volcanoes as mountains of solid rock.
14:54Deep beneath, rock is so hot and pressurized that it bursts violently out as lava.
15:09But not all volcanoes work this way.
15:14There are volcanoes on other worlds that don't use molten rock at all.
15:23Right at the frontiers of the sun's planetary system, Triton orbits the ice giant Neptune.
15:31Two and a half billion miles from the sun, the temperature is a frigid 390 degrees below zero.
15:42When NASA's Voyager probe flew past, it revealed a world covered mostly with frozen nitrogen ice.
15:52But the probe found something else.
15:58When Voyager flew by, it saw these black smudges and all of the smudges were going in one direction,
16:04almost as if there was a wind blowing dark material, dust, in one direction.
16:10Signs of activity on a world so cold it freezes nitrogen.
16:16Volcanoes at almost 400 degrees below zero.
16:26Forget molten rock. Triton spews out a mixture of nitrogen and moon dust.
16:35And the geyser not only has liquid nitrogen, which is in a fluid form,
16:41but also some sort of dusty stuff that's lighter that can even go farther in the weak winds.
16:47So you have this wonderful sort of double plume of an icy area and then a darker smudgy area,
16:52basically made of dust, like moon dust.
16:56Triton's surface is nitrogen ice.
17:01How?
17:04Scientists believe it's because nitrogen ice lets light in, but doesn't let heat out.
17:12There's almost a bit of a greenhouse effect going on on Triton,
17:16that there's a layer of nitrogen ice that's transparent.
17:19And just like a greenhouse here on Earth, when you have glass, light can pass through it,
17:23but then the heat is trapped by the glass.
17:28The sun shines through the surface and warms the nitrogen beneath.
17:38Just a few degrees is all it takes to turn nitrogen ice into gas.
17:46A temperature gradient, a change in that temperature, that's what's important.
17:50And that's enough to melt the nitrogen underneath the surface on Triton
17:54and burst through as a geyser.
18:02This is a cryovolcano, so cold that the material it erupts would freeze water as hard as rock.
18:14The solar system is more active than we ever imagined.
18:20We have found weird eruptions on many planets and moons.
18:29But so far, the only world where volcanoes are linked to life is ours.
18:35Or so we thought.
18:44This is Europa.
18:48It orbits Jupiter nearly 500 million miles from the sun,
18:52a frozen, 2,000-mile-wide rock-hard ball of ice.
19:00From a distance, its surface looks smooth.
19:04Up close, it's a different story.
19:09Jupiter's enormous gravity gives Europa a pounding just like its neighbor Io.
19:16The surface heaves and flexes, creating ridges and deep crevices.
19:24When we first got close-up images of Jupiter's moon Europa, they looked a little familiar.
19:30And it turns out it looks like ice flows that you see when you fly over the Arctic.
19:34And it turns out it's the same thing.
19:37Europa has a several-mile-thick shell of ice on its surface.
19:42And beneath that is a global liquid ocean.
19:51Magnetic readings suggest Europa has an ocean that's a staggering 60 miles deep.
20:02Jupiter's gravitational pounding heats the rocky core and melts the ice above.
20:09It's not unreasonable to think that as the core is being stretched by tides and heated up,
20:15possibly even molten, there's some boundary between a hot core and a liquid water ocean.
20:30On Earth, underwater eruptions are surrounded by life.
20:37The same could happen on Europa.
20:42Here, the darkness is total.
20:46The pressure, a crushing 2,000 Earth atmospheres.
20:52A brutal world, but perhaps a cradle for life.
20:58If life got off the ground here on Earth, why not on Europa?
21:03All the ingredients are there.
21:05An energy source, volcanic activity.
21:08A universal solvent, liquid water.
21:11A rich hydrocarbon chemistry.
21:13We have this mixing bowl of ingredients that happened on the Earth 3.5 billion years ago.
21:19And we have similar conditions on Europa.
21:22So some people are saying, if it happened here, why not there?
21:28Life on Europa would be hard, but not impossible.
21:33On Earth, there is life at every extreme.
21:37Searing heat, crushing pressure, total darkness.
21:43Alien life on Europa might look surprisingly similar.
21:49If life exists under the ice cover of Europa,
21:53they would be aquatic, but without eyes, because there's no light to speak of.
21:58They would probably use sonar in order to make sense of their surroundings.
22:04Organisms that literally feed off the energy from the volcano.
22:10On Europa, volcanoes could be the source of new life.
22:18It's even possible that Europa is normal.
22:21That this is how worlds with life generally are.
22:26Earth could be the exception.
22:32Think of it. Europa could be a template for billions of moons out there that have liquid oceans on them.
22:39So all of a sudden, our horizons have expanded several billion times by looking at the moons of Jupiter.
22:47What a shock.
22:52Our solar system alone has over 170 moons.
22:57Multiply that across the universe, and that's a lot of places where life might take hold.
23:05All it takes is liquid water and a source of energy.
23:10Potentially, volcanoes provide both.
23:14And they are everywhere.
23:19This is Saturn, twice as far from the sun as Jupiter.
23:25Yet it too has volcanic moons.
23:30And just like Jupiter's Europa, these moons could harbor life.
23:38This is one of the strangest worlds in our solar system.
23:43Saturn.
23:46A region of the solar system that has never been seen before.
23:51But it's a strange place.
23:55It's a strange place.
23:58It's a strange place.
24:01The strangest worlds in our solar system.
24:04Saturn.
24:07A ring system 600,000 miles wide.
24:11An amazing 62 moons.
24:15And one with a secret.
24:19Enceladus is one of Saturn's smaller, more distant moons.
24:22And it's been known for a long time that it's covered in ice because it's very bright, very reflective.
24:27But when the Cassini spacecraft went there, it discovered something amazing.
24:33The Cassini probe revealed something incredible.
24:37Not on the planet itself, but on Enceladus.
24:46Backlit by the sun, a gigantic plume bursts out into space.
24:52A sure sign of volcanic activity.
25:04It was an amazing discovery, and it helped answer a question that has puzzled scientists for decades.
25:12The mystery of Saturn's E ring.
25:18Saturn's outermost ring is vast.
25:22Almost 200,000 miles across.
25:26And it shouldn't exist.
25:30The ice particles that make up most of the ring are too far from Saturn to stay in orbit.
25:36They constantly drift away into space.
25:43Something replenishes the ring.
25:47Volcanoes of Enceladus.
25:52Those plumes that are ejected from Enceladus' south pole, it turns out that those are going into space.
25:57And they're not just going away.
25:59They're feeding a ring around Saturn, the E ring.
26:05So this little moon is giving something back to its parent planet.
26:18Water blasts from Enceladus' volcanoes, hits the vacuum of space,
26:25and instantly freezes into tiny ice crystals, creating the vast E ring.
26:36One mystery solved.
26:39Another replaces it.
26:42What creates the volcanic plumes?
26:47Cassini's cameras zoom in on the moon's south pole
26:51and capture these huge chasms scarring the surface.
26:57There are these wonderfully huge cracks at the south pole of Enceladus.
27:01And as Enceladus goes around Saturn, these cracks open and shut as the tides go by.
27:06Now, these cracks are huge.
27:08They're hundreds of miles long.
27:10And when they begin to open, you would have this big crevasse
27:13spinning at maybe 100 miles an hour down the length of that.
27:16It would be incredibly spectacular.
27:20Huge gravitational forces crack the surface open and closed at enormous speeds.
27:28Like Europa and Io's orbits around Jupiter, Enceladus' orbit around Saturn is elliptical.
27:40This helps generate the heat to melt ice and create oceans of water beneath the surface.
27:48The conditions of the water underneath Enceladus' surface are absolutely perfect for life.
27:53It's the right temperature. It'd be a good pressure for life.
27:56Liquid water would be just like seawater here on Earth.
27:59And the chemistry of the water we see shooting out of these vents suggests that it is very similar.
28:04There's salt. There's organic material in it as well.
28:07So we've identified a place in the solar system where there very well may be life right now.
28:18Cassini has detected complex carbon molecules in the ice plumes.
28:24Combined with liquid water, these suggest that just maybe,
28:28life could survive deep within this enigmatic moon.
28:38Enceladus may not be alone.
28:41Another of Saturn's moons might also harbor life.
28:45Titan, one of the largest moons in our solar system.
28:51The only moon with a thick atmosphere.
28:56A frozen world. Ice as hard as rock.
29:01Lakes of liquid methane.
29:05Yet here too, we might find evidence of volcanoes and the tantalizing prospect of alien life.
29:25A raging inferno on the surface of Io.
29:29Eruptions of ice and nitrogen on Triton.
29:35Volcanoes are one of the most destructive forces in our universe.
29:44But out of annihilation comes the possibility of life.
29:50Even here on Saturn's mysterious moon, Titan.
29:57It's 3,000 miles across.
30:01Larger than the planet Mercury.
30:05It's the only moon in our solar system with a thick atmosphere.
30:11There is weather here. Storms, winds, rain, even lakes.
30:17All so cold that liquid methane takes the place of water.
30:24And it's loaded with chemicals that life needs to survive.
30:30Titan has turned out to be absolutely one of the most interesting places in the solar system.
30:35It's an active world. It's the only moon with a thick atmosphere.
30:40An atmosphere very much like Earth because it's mostly nitrogen.
30:43And it turns out an atmosphere loaded with organic molecules.
30:49Methane gas high in Titan's atmosphere reacts with sunlight
30:54and creates the kind of chemicals life depends on.
31:00But if sunlight converts methane into organics continuously,
31:06why doesn't the methane run out?
31:12The atmosphere is full of methane
31:14and yet we know methane is being destroyed by sunlight on a short timescale
31:17so sunlight shouldn't be there. There needs to be a source of methane.
31:22Something on Titan pumps out a continuous supply of methane.
31:29Cassini has detected what looks like a crater.
31:33Its interior is as deep as the Grand Canyon.
31:37Infrared cameras reveal different types of materials surrounding the crater.
31:44Scientists believe the green areas could be volcanic.
31:49Perhaps planes of lava ejected from Titan's interior.
31:58If it exists, lava, Titan-style, is a super-chilled icy slush.
32:06But compared to the rest of Titan, even ice slush is scalding hot.
32:12On Titan, the hot liquids spewing from volcanoes might be ammonia or water.
32:18Normally those are frozen solid on the surface,
32:20but if they're heated beneath the surface somehow, they could erupt out.
32:24On Titan, what comes out of volcanoes is methane and ethane.
32:29And that's probably the reason why we have this very thick cloud cover,
32:33this orange haze around Titan.
32:36That haze probably came from outgassing from the volcanoes of Titan.
32:42Even for volcanoes on a world as cold as Titan, you need heat.
32:47That's what turns ice into liquid and generates eruptions.
32:55On Titan, that heat has two sources.
33:01Two active materials warm the interior.
33:08And Saturn's huge gravity massages the moon, just like Enceladus.
33:16These two forces generate enough heat to turn ice into water and liquid methane to gas.
33:25We think of volcanoes as being hot and ice as cold,
33:28and yet if you're out on Titan, where you're a billion miles from the sun and it's quite cold,
33:36then those flows of just barely above freezing water, ammonia, ice,
33:41they might be the hottest things around.
33:43So hot is a relative term depending on where in the solar system you are.
33:51Could volcanoes on Titan give life a chance to survive here?
33:56Life as we know it needs an atmosphere,
34:02a solid surface,
34:05liquid water,
34:07and the heat to drive chemical reactions.
34:10On Titan, volcanoes could provide them all.
34:16If you have a volcano on Titan, you'll have heat added to that,
34:20and all of a sudden you'll have liquid water surrounded by organic material.
34:24I mean, literally anything you need for the start of life.
34:28If life does exist on Titan, it would be truly alien.
34:34It would breathe hydrogen in place of oxygen,
34:38perhaps swimming through lakes of liquid methane at 300 degrees below zero.
34:46Perhaps there are oceans of ethane.
34:48Perhaps there are tide pools and perhaps volcanic activity and hydrothermal activity.
34:54Perhaps there are hot springs.
34:56Perhaps volcanic heat could generate enough to get life off the ground in Titan.
35:03That's a speculation, but it can't be ruled out.
35:08But we may not need to travel this far to find signs of life.
35:14We may find it on a volcanic world much closer to home.
35:20The Red Planet, Mars.
35:25NASA Jet Propulsion Laboratory, California Institute of Technology
35:38Volcanoes are everywhere across the solar system.
35:45Worlds like Io, Titan, and Triton are complex, dynamic, and violent.
35:55Once we thought that Earth was the only planet with volcanoes, and with life.
36:04Now we find volcanoes everywhere, but we have yet to find alien life.
36:12Volcanoes embody the sheer power of creation and destruction, and they go hand in hand.
36:18It is literally true that if there weren't volcanoes here, we would not be here either.
36:22In the cauldrons of volcanoes is the origin of life.
36:28Volcanoes create new landscapes.
36:32Seed the atmosphere with complex chemicals.
36:36Replace the old with the new.
36:42If volcanoes are bound up with the processes of life, then where is the life on other worlds?
36:56Perhaps the answer originates in deep time when the solar system was young.
37:04On a young planet, much like our own.
37:10This is Mars.
37:15Three billion years ago, it had active volcanoes.
37:21One still remains the largest volcano in the solar system.
37:29The cliffs leading to it are over six miles high.
37:35Mount Everest would sit comfortably in their shadow.
37:40And those are just the foothills.
37:44This is the awe-inspiring Olympus Mons.
37:50It covers an area the size of Arizona.
37:54Its crater alone is 53 miles wide.
37:59A Goliath like this takes millions of years to build.
38:03Time that volcanoes here on Earth never get.
38:12On Earth, the crust is always moving.
38:21Deep below, a single hotspot pushes magma through the surface, building a new volcanic island.
38:29But while the hotspot stays still, the surface is moving.
38:34The new island moves away from the hotspot, and a new volcanic island takes its place.
38:44Mars is different. The crust is locked solid.
38:50On Mars, there's just none of that tectonic activity.
38:53Mars is one big solid plate, and so if there's a hotspot, it just sits there and builds and builds and builds,
38:59and you get a bigger and bigger and bigger volcano.
39:01And that's why Olympus Mons is so huge.
39:12Olympus Mons today is a frozen relic of a distant, warmer past.
39:23Mars' shrunken atmosphere means that Olympus now reaches almost into space.
39:31A true colossus. An extinct volcano on a dying world.
39:43But Mars' ancient volcanic terrain could one day harbor life again.
39:51The evidence is right here on Earth.
39:58On Hawaii, volcanoes have created mysterious tunnels called lava tubes.
40:06Channels left behind when torrents of molten rock surge into the sea.
40:13But some are now empty, and that offers us an opportunity.
40:22Lava tubes are formed when you have an underground river of hot basaltic lava,
40:282,000 degree magma, molten rock, and picture it like a frozen river of water
40:37with an ice crust forming on the top.
40:43It's the same thing, only here the crust is solid rock,
40:47and the river keeps flowing underneath and makes this cave, this lava tube.
40:52Extraordinary recent images suggest Mars' volcanoes also may have created lava tubes.
41:00Any planet with basaltic volcanism, any rocky planet, will probably have lava tubes.
41:06And now we've found a couple of them on Mars, in places where there are skylights,
41:10places where the roof has collapsed, and you can see from orbit right into those lava tubes.
41:16If some tubes have collapsed, perhaps many others are still intact.
41:22The ancient relics of Mars' volcanic past.
41:29Now, after lying dormant for perhaps millions of years,
41:34these lava tubes could bring life back to the Red Planet.
41:41That life will be us.
41:46One of the challenges of living on Mars for future humans will be the radiation environment,
41:52and in particular, when there are solar storms, the cosmic rays coming in can be deadly.
41:58And having a storm shelter under some large mass of rock
42:04is really the best way to protect yourself from cosmic rays.
42:11The tubes and caves of Mars' extinct volcanoes might one day make a perfect home.
42:19Holding in air, shielding us from deadly radiation,
42:25a long-dead volcano could help fill a world with new life.
42:35Volcanoes can destroy, but they can also create.
42:41From the superheated vents of Europa's 60-mile deep ocean,
42:47to the water volcanoes of Titan and the rock volcanoes of Earth.
42:53Vast geologic processes shape our worlds, our imaginations,
42:59and perhaps the very stuff of life.