How the Universe Works - S03E03 - Jupiter - Destroyer or Savior
Category
📺
TVTranscript
00:00Jupiter, a cosmic colossus reigning over the other planets.
00:08Take the planet Earth, now get a thousand of them, and that's the size of Jupiter.
00:13Hidden beneath its swirling clouds lie the secrets of our solar system's formation.
00:20When the biggest thing in the solar system is moving this far this fast, it changes everything
00:25around it.
00:26And the birth of life.
00:29If it wasn't for Jupiter, right where I'm standing, there might be a gigantic meteor
00:35impact crater.
00:39Now scientists are unlocking the gas giant's secrets, and discovering that Jupiter, more
00:45than any other planet, shapes our solar system's past, present, and future.
00:54Without Jupiter, most certainly we wouldn't be here to talk about it.
01:13Jupiter, named after the Roman king of the gods, the god of the sky, it looms between
01:20the four inner rocky planets, and the three frozen gas giants beyond.
01:27It is our largest planet by far.
01:31Jupiter is the king of the planets, and that's because it is the biggest of the planets.
01:35It has a storm on it that's actually four times bigger than the Earth itself, and it's
01:39been raging for hundreds of years.
01:41It has dozens of moons, this gigantic magnetic field.
01:46Everything about Jupiter is just huge, it doesn't do anything small.
01:49If you were looking at our solar system from afar, you'd look and say our solar system
01:53is made of the sun, Jupiter, and assorted rubble.
01:58This vast planet contains the clues to our solar system's formation, its evolution, and
02:05its eventual death.
02:08Jupiter is a cosmic time capsule.
02:11If only we could open it.
02:14In the Roman myth, Jupiter, the god, drew a veil of clouds around him to hide his mischief,
02:19and that's to some extent what's happened when we look at Jupiter.
02:22We're seeing not the surface of a planet, but the edge of a cloud.
02:28This shroud of gas hides Jupiter's deepest secrets.
02:32One of the big mysteries of Jupiter is what's at the very center, what is its core?
02:36And this is something that we actually don't know yet.
02:39But we do know that what's happening inside Jupiter gives the planet its power.
02:44If we want to know more about what's going on in this king of the planets, we're going
02:49to need to be able to part those clouds and peer inside.
02:53Simple physics tells us that its massive atmosphere is nightmarish.
02:59Because it's a gas giant, the atmosphere, as you get deeper into it, just gets denser
03:04and denser and the pressure gets higher and higher.
03:07From the cloud tops to the planet's center is 43,000 miles.
03:13That's a three-day non-stop journey in a jumbo jet.
03:16The descent would be a hellish roller coaster ride.
03:20And we know, because we've tried.
03:24The Galileo probe orbited Jupiter for years, looking at the cloud tops of the planet and
03:29the moons that orbit it.
03:30But at the end of the mission, they decided they could do one more scientific experiment.
03:36December 7, 1995, NASA's Galileo spacecraft drops a 750-pound titanium probe into Jupiter's
03:46atmosphere.
03:48It slams into the cloud tops at over 106,000 miles an hour.
04:03Even though Jupiter looks calm and serene from a distance, as you get closer, you realize
04:08that there are ferocious winds, there are lightning storms, and there are pressures
04:13that would crush any instrument.
04:15The planet is a thousand times the mass of the Earth, and that means as you go inward,
04:20the pressures and densities become very large.
04:25The probe's sensors reveal that hydrogen makes up 90% of Jupiter's atmosphere.
04:33Temperatures soar to over 300 degrees.
04:40Winds rage at 400 miles an hour.
04:46It's hotter and more turbulent than scientists ever imagined.
04:53Fifty-eight minutes after entering Jupiter's atmosphere, and just 95 miles down, the probe
05:01vaporizes, leaving most of Jupiter's secrets beyond our reach.
05:11We can't reach the planet's center.
05:16But at the National Ignition Facility outside San Francisco, scientists can recreate conditions
05:22deep inside Jupiter.
05:28There are a lot of other facilities where we can generate, say, states that are found
05:33at the center of the Earth, or some of the other terrestrial planets, but this is the
05:38only place you can recreate the deepest interior of Jupiter.
05:43The team takes hydrogen, the most common element in Jupiter, and freezes it, increasing its
05:49density.
05:51Then they fire up the world's largest laser.
05:55Multiple laser beams race through a series of amplification chambers, intensifying by
06:00a quadrillion times, until, perfectly synchronized, the beams converge.
06:08For 20 billionths of a second, the laser bombards the hydrogen with 1,000 times more energy
06:15than the entire United States uses at any given moment.
06:20Turns out that at those very extreme pressures, 100 million atmospheres of pressure, chemistry
06:28is just completely different.
06:33Instead of really distorting the chemical bond, now you're distorting how the atom itself
06:40behaves.
06:42Matter behaves in a fundamentally different way than we experience it here on Earth.
06:48The atoms break down, transforming the hydrogen gas into a liquid, a liquid metal concentrated
06:56deep inside the planet.
06:58Essentially you would have this very dense structure, and it perhaps would look like
07:05this massive ball of mercury at the center of Jupiter.
07:09Under immense pressure, the liquid hydrogen emits energy as heat, pushing temperatures
07:14at the edge of this metallic sphere up to 11,000 degrees.
07:20What lies inside remains a mystery.
07:24There could be a little rocky planet underneath all of that gas and all of that liquid.
07:29It could be more of a ball of super compressed ice.
07:32There probably is something solid down there.
07:36It's the processes happening inside Jupiter that give the planet its power.
07:43Power to shape the solar system since its earliest days.
07:49Jupiter is the biggest influence in the solar system apart from the sun.
07:54But this monster is shrinking.
07:57Is Jupiter losing its power?
08:06A thousand times more massive than the Earth, Jupiter could swallow all the other planets
08:16in the solar system twice and still have room for more.
08:22But this giant is getting smaller.
08:26Gravity is still bringing all of the gases and liquids together.
08:31And that heats up the interior of Jupiter.
08:35As heat rises up to Jupiter's surface and escapes into space, the planet cools and shrinks,
08:43making the gas giant a third smaller today than when it first formed.
08:49As the planet cools, the shrinking slows, from an inch a year in its infancy to just
08:55a few fractions of an inch today.
08:59It could continue shrinking for a thousand billion years.
09:04Even then, it will always be the solar system's biggest, most powerful planet.
09:12Jupiter is shrinking too slowly for us to see.
09:15But we can see the effect of this rising heat.
09:19This is actually one of the reasons Jupiter has the spectacular weather, all those beautiful
09:23bands of clouds.
09:29On Earth, the sun's heat drives our weather.
09:33Switch off the sun, and our weather would stop.
09:37But Jupiter's weather would keep on going.
09:41Its weather doesn't come from the sun.
09:43It comes from deep inside the planet itself.
09:49Heat rises up through the boiling soup of gas, creating Jupiter's spectacular swirling
09:56clouds.
10:00And the whole time, the giant planet spins.
10:04At 29,000 miles an hour, Jupiter rotates faster than any other planet in our solar system.
10:14Jupiter rotates on its axis about once every nine hours, compared to a 24-hour day for
10:19us.
10:20So, huge, superheated clouds from the interior get smeared out by the rotation, and we have
10:25the beautiful cloud tops of Jupiter.
10:27This marriage of heat and motion spawns a monster.
10:34Jupiter's red spot is a gigantic cyclone larger than the size of the Earth, and has been rotating
10:41stably with winds in excess of 250 miles per hour for over three centuries.
10:47Imagine a storm that lasts for 300 years.
10:52On Earth, cyclones die when they hit land, but Jupiter has no land to stop its storms,
10:59almost unlimited heat to fuel them, and a rapid rotation.
11:08Jupiter is basically stoking the fires of the great red spot.
11:13We're used to storms growing and then going away on Earth.
11:16But if they're spinning the right way, because Jupiter is so big and spinning so quickly,
11:20they feed into each other, and it keeps the storm alive.
11:26Long after the other planets freeze and die, Jupiter will still be pumping out heat, driving
11:32its monster storms, thanks to its immense size.
11:42And the secret of its size lies in the solar system's infancy.
11:47Just over 4.5 billion years ago, in the disk of dust and gas left over from the sun's formation,
11:55the first planet forms.
11:58Jupiter began to form early on, and began to gobble up water, frozen comets, meteors,
12:05and grow.
12:07When you imagine a litter of animals, one of them usually wins.
12:12And the one that wins is the one that begins to eat the most first.
12:16The same thing happened with Jupiter, in some sense.
12:20Jupiter forms at the right time, and in the right place.
12:25Just inside the frost line, the point 320 million miles from the sun, where water vapor
12:32turns to ice.
12:35Close to the sun, wacky planets cannot grow very big.
12:39A little bit bigger than the Earth, and the planet falls apart.
12:42Further out, however, ice is a glue that can hold rock together.
12:47And so you have massive, rocky ice planets, big enough to capture hydrogen gas and become
12:54a gas giant.
12:58Close to the sun, gas is too hot and energetic to stick to anything.
13:03Out here, gas is cold and sluggish.
13:07So when gravity pulls gas towards Jupiter's core, it sticks, and Jupiter balloons.
13:16And as it grew, its gravity grew, and therefore its ability to gobble up more increased.
13:22So it was the lucky winner by starting early and eating often.
13:29The planet eats everything in its reach, until it becomes the giant we see today.
13:38But 4.5 billion years ago, Jupiter is in the wrong place.
13:43Ice spiraling towards the sun, and a fiery death.
13:59The biggest planet with the biggest influence, Jupiter is unique in our solar system.
14:10But not in our galaxy.
14:13October 1995, scientists discover the first planet beyond our solar system.
14:2151 light years from Earth, 51 Pegasi b is a giant gas planet, similar to Jupiter in
14:30every way, except one.
14:33The first exoplanet found orbiting a star like the sun was a huge surprise.
14:37It was called a hot Jupiter, because it's something roughly the size of Jupiter, but
14:41it was tremendously close in to its star, much closer even than Mercury is to the sun.
14:48Since that first discovery, astronomers have identified hundreds of gas giants outside
14:54our solar system.
14:56Many orbit extremely close to their parent star.
15:02The planet WASP-33b orbits so close to its star that its surface is a scorching 5,800
15:10degrees.
15:11It's the hottest planet ever observed in the universe.
15:18Now we know that planets like that can't form there, it's just too hot to be able to coalesce
15:22from all that gas.
15:24These hot Jupiters must have formed farther out.
15:28How do you get a Jupiter-like planet that close to a star?
15:32Somehow you need to be able to build a big planet and then move it in.
15:36And this had us asking all kinds of questions.
15:38If we see it going on elsewhere in the universe, is that how our own solar system worked too?
15:43So now when we look at Jupiter, we think, alright, that's where it is today, but it
15:47doesn't mean it's always been there.
15:48It could have moved all over the place, and it just ended up where it is where we find
15:53it today.
15:54How did this giant gas planet end up where it is today?
15:59And what effect did a migrating Jupiter have on the other planets?
16:06Walsh and his team re-imagine the solar system.
16:09They set Jupiter adrift, and in the process, they solve one of the solar system's greatest
16:16puzzles.
16:18We would build our models, we'd get a Venus right where the Venus is supposed to be, we'd
16:23get an Earth right where the Earth is supposed to be, but where Mars is today, we were usually
16:29getting a Venus or Earth mass planet.
16:31No matter what we did, no matter how we changed the model, we were always getting a really
16:35big Mars.
16:36All of our simulations show that Mars, where it is in the disk, should have been at least
16:40ten times the mass that it is.
16:42Something came in and literally ate Mars' lunch.
16:46And that something was Jupiter.
16:494.5 billion years ago, Jupiter forms 325 million miles from the Sun, roughly a third closer
16:58than it is today.
17:00The orbiting planet collides with the debris left over from the Sun's formation, and these
17:05collisions slow it down.
17:08It loses momentum, and the Sun's gravity pulls it closer.
17:13Jupiter spirals inward, gobbling up the raw materials that should have made Mars.
17:20So seeing that result, seeing a great solution to the small Mars problem, was kind of the
17:25eureka moment.
17:26Like, well, maybe there's a mechanism out there.
17:28We know that planets migrate, so let's put these two things together and maybe this is
17:32going to work.
17:34As Jupiter travels inward, it bulldozes the rocky material that lies in its path.
17:41In the inward migration, there's a lot of material there, it actually pushes almost
17:45all of that, about 80 percent of it, inward.
17:49And when we make the movies in a certain way, it really looks like a snowplow.
17:57The gas and dust squeeze into an inner disk around the Sun.
18:02As Jupiter orbits, it pushes against this disk, creating a bulge.
18:08The bulge races around the disk, pulling Jupiter with it.
18:15Jupiter tries to pull away from the Sun, but the debris behind Jupiter continues pushing
18:21inward.
18:22It's a cosmic stalemate, with the planet trapped between the inner and outer disks.
18:29Then, something extraordinary happens.
18:33The giant planet changes direction.
18:38As we're building this model, we've had this vision of Jupiter coming inwards, turning
18:41around and going outwards.
18:42And we thought of it as a sailboat, kind of tacking, coming about, turning through the
18:47wind.
18:48So, the name, the Grand Tech model, it actually comes from sailing terminology.
18:53But Jupiter is no yacht.
18:55It's a giant super-tanker of a planet.
18:58Changing its course is going to take something seriously powerful.
19:04Enter the solar system's second largest planet, Saturn.
19:10Like Jupiter before it, Saturn has spiraled inward, closing in on the giant planet.
19:17Amazingly, there was this wonderful interplay between Jupiter and Saturn.
19:22As they ate up all the material around them, there was a gap in the disk left over.
19:27With less material behind Jupiter and Saturn, there's less holding the planets in place,
19:33allowing the force from the bulging disk to fling Jupiter back out, with Saturn hitching
19:39a ride.
19:40The key for stopping Jupiter's inward migration in the Grand Tech is Saturn.
19:46Saturn growing at the right time and at the right place allowed it to migrate close to
19:51Jupiter and change and stop Jupiter's inward migration.
19:57Saturn saves Jupiter from a fiery fate.
20:01And this Grand Tech leaves a parting gift, the Earth itself.
20:09Because when Jupiter migrates out, it leaves behind the rocky debris it bulldozed in.
20:16It's from this debris that the Earth forms.
20:21But beyond Mars, Jupiter's powerful gravity pulls on the debris, preventing it from sticking
20:28together, leaving the rubble scattered as a belt of asteroids.
20:34Jupiter's gravity is so strong that it determines, in some ways, what can exist where in the
20:40solar system and what can't.
20:46The rocky planets, our planet, and beyond Mars, the asteroid belt, they all exist because
20:57of Jupiter's epic journey.
21:00When the biggest thing in the solar system is moving this far this fast, it changes everything
21:03around it.
21:07Five million years after it first formed, Jupiter reaches its present orbit.
21:14Its outward movement and the inward pull of the sun's gravity are finally balanced.
21:21This is still not the solar system that we see today.
21:27The end point of the Grand Tech model was actually the ideal beginnings of what we think
21:31happened later on in solar system history.
21:36Because from this stable orbit, Jupiter is about to trigger a deadly domino effect that
21:42threatens to destroy the infant Earth.
21:514.5 billion years ago, Jupiter orbits between the rocky inner planets and the icy outer
22:04planets.
22:07From this strategic vantage point, the gas giant dominates our planetary system and unleashes
22:14hell.
22:20In the early environment of the solar system, where there was a lot more junk surrounding
22:25the Earth than in the inner solar system, the Earth was bombarded, as were all other
22:30objects, at an incredible rate.
22:35It's an incredibly violent time in solar system history.
22:39We refer to that time scale about several hundred million years after the planets actually
22:44formed as the late heavy bombardment.
22:54These were very large scale impacts, and they actually do create melt pools, liquid rock
22:59on the floors of these impact craters.
23:01And some of those craters can glow hot for tens of thousands, hundreds of thousands of
23:06years in some cases.
23:07If we were actually on the Earth at that time, there would have been enormous pawls of dust
23:12continuously thrown into the atmosphere.
23:14The sky would be hazy, cloudy, and the terrain would be mountainous from the rims of craters
23:20all around, rocky, and a wholly unpleasant place to be.
23:36Today the scars have healed.
23:40Stars advance and retreat.
23:44Volcanoes erupt.
23:46Wind and water erase our planet's past.
23:51But the evidence is still visible, if we look up.
23:55Look at the moon.
23:56Every night you see the moon coming out, and it's pockmarked, because for about a billion
24:01years after the solar system was formed, there was chaos.
24:08NASA's Spitzer Space Telescope reveals this kind of bombardment around another star.
24:17Astronomers see a vast disk of gas and dust circling a young star called Eta Corvii.
24:24This may be evidence of icy comets and asteroids swarming into its inner solar system.
24:32Four billion years ago, the same thing was happening in our solar system.
24:41There was a wave of material, asteroids and comets, that swept in from the outer solar
24:46system.
24:47It turns out it probably came from Jupiter and Saturn, the outer planets.
24:51As they were orbiting the sun, they were interacting with each other gravitationally, a very complicated
24:56dance.
24:58Jupiter goes around the sun three times, every two times the Saturn does.
25:02And so when they would migrate outwards, they'd be locked in this resonance, they'd
25:05be very close to each other.
25:06And at some point, as they were moving around, their gravitational powers basically combined,
25:12got a little bit better at affecting the material around them.
25:16Together, the two inner gas giants sling the two outer gas giants, Uranus and Neptune,
25:24even farther out.
25:27Uranus and Neptune swap places.
25:34Neptune slams into the frozen dust and gas in the solar system's outer reaches, scattering
25:41icy debris far and wide.
25:46This debris collides with the asteroid belt.
25:51Billions of comets and asteroids swarm across the orbits of the Earth, Moon and other inner
25:57planets.
25:58If that had persisted, then life never could have evolved.
26:03Only after a few hundred million years was it possible for life on Earth to develop.
26:12But this destruction contains the seeds of creation, because the icy comets deliver a
26:19precious cargo.
26:22Water periodically disturbs objects in the outer solar system, largely water objects,
26:27and directs them towards the Earth.
26:28Nowadays, that would be a disaster.
26:30But in fact, if you look at the water on Earth, it's quite likely that almost all of the
26:35water on Earth that's now here came from ice that impacted upon the Earth, directed here
26:40by Jupiter.
26:46Every ocean, every river, every raindrop may owe its existence to Jupiter.
26:55The gas giant may even have sowed the seeds of life itself.
27:01The chemical building blocks of life may have hitched a ride to Earth on board a comet.
27:08Without Jupiter, life would never have started, and it would never have survived.
27:17The main bombardment ended 3.8 billion years ago, but a threat remains.
27:23NASA's Near-Earth Objects Program scans the skies for potentially dangerous asteroids
27:29and comets.
27:30So far, they've spotted over 10,000.
27:35It only takes one to cause a catastrophe.
27:39Just three miles wide, this small comet is big enough to wipe out life on Earth.
27:45Luckily, Jupiter is in the way.
27:49Jupiter acts in a lot of ways like the protector of the inner solar system.
27:53By shepherding comets in its vicinity, ejecting them from the solar system, Jupiter helps
27:57protect the Earth itself.
28:02In a sense, the way objects move in the solar system is a little bit like a roller derby.
28:08You've got all of these objects moving around the sun in the same direction, going around
28:11and around and around, but they have gravity and they can interact with each other.
28:17Imagine this skater in white is an icy comet racing in from the outer solar system.
28:24The skaters in black are the gas giants.
28:28The comet veers across the planet's orbits until it encounters Jupiter.
28:34Jupiter moves faster than the comet.
28:37The giant planet's gravity grabs the comet and gives it an assist in a slingshot maneuver.
28:45The comet steals some of Jupiter's momentum, accelerates, and changes direction.
28:54Jupiter can fling it out of the solar system by giving it that extra velocity, and it goes
28:58away.
28:59It's ejected.
29:01Jupiter slings objects out and stands guard.
29:05Every year, 200 times more comets and asteroids smash into Jupiter than the Earth.
29:12Something had to be there, like a sheriff, to clean out all the riffraff and clean out
29:17all the debris, and that's the planet Jupiter.
29:21If it wasn't for Jupiter, right where I'm standing, there might be a gigantic meteor
29:26impact crater.
29:28Without Jupiter, most certainly we wouldn't be here to talk about it.
29:34Our lives depend on Jupiter.
29:38Because of the incredibly important role that Jupiter has played in the evolution of life
29:43on Earth, when we look at exoplanets, when we look for life elsewhere in the universe,
29:48we may not need to look just for those habitable planets.
29:51We may need to look for Jupiters, or objects like them, that have saved them as Jupiter
29:56saved us.
30:00Jupiter is the secret behind our solar system's success.
30:07It makes life on Earth possible, and helps protect that life.
30:14It may even nurture life, alien life.
30:30Jupiter dominates its neighborhood for millions of miles, looming over at least 67 moons,
30:37from Ganymede, which is larger than the planet Mercury, to a rock barely a mile across.
30:45The innermost moons are more rocky rich, the outermost moons are more ice rich, so in a
30:50lot of ways a little miniature solar system.
30:56Jupiter is a cosmic puppet master, controlling and manipulating its moons, and perhaps making
31:03one of them home to life.
31:07On March 1, 2007, NASA's New Horizons probe flies past Io, a moon roughly the same size
31:16as our own.
31:19Io is one of the most interesting moons in the solar system, and not just because it
31:22looks like a pizza, it's covered with volcanoes.
31:26In fact, these volcanoes, one way or another, have been continuously erupting since we've
31:30been observing Io with space probes for the past 20 years.
31:40This small moon is the solar system's most volcanic body, with at least 400 active volcanoes.
31:49Together, they pump out 100 times more heat than those on Earth.
31:58Io's orbit is actually slightly eccentric around Jupiter.
32:01Sometimes it's a little closer to Jupiter, sometimes a little farther away.
32:06As the gravitational field changes, Io's body, the structure of the moon itself, is twisted
32:11and pulled back and forth.
32:14And that heat, through friction, the interior of the moon, that heat basically melts it
32:19and that erupts through the surface as volcanoes.
32:24The volcanoes on Io are really fascinating.
32:28They're ejecting vast quantities of sulfur dioxide above the surface of Io.
32:35It's split apart by the ultraviolet light from the sun into sulfur ions, oxygen ions,
32:40and those ions interact with the magnetic field of the planet Jupiter.
32:46Jupiter's magnetic field carries chemicals and charged particles away from Io and onto
32:52its neighboring moon, Europa, making this distant frozen world one of our best hopes
33:01of finding alien life.
33:06When we got up close to Europa with spacecraft, we saw it was covered in cracks and ridges,
33:10which looked very much like the way ice flows look here on Earth.
33:13And it turns out that's exactly what's going on.
33:16We know, because of seeing the flexure of the ice and the cracks in the ice on the surface
33:20of Europa, that there's probably a subsurface ocean deeper than the deepest of Earth's
33:25oceans there on that little icy moon.
33:34Jupiter's gravity pushes and pulls Europa, creating friction, generating heat, and melting
33:44Europa from within.
33:48Jupiter is so far away from the sun that it's natural to assume that anything around it
33:52is frozen.
33:53The fact that gravity can heat something up enough to produce liquid water is profoundly
33:59important.
34:00All of the indications of liquid water under the surface have been indirect, the way the
34:04surface looks, the resurfacing of it.
34:07But very recently, we got direct evidence of water under the surface of Europa in the
34:12form of a geyser, a plume of water being ejected from the south pole of the moon.
34:20November 2013, analyzing photographs from the Hubble Space Telescope, scientists spot
34:27two giant geysers spewing water 124 miles into the atmosphere above Europa's south pole.
34:35It's the best evidence yet of liquid water beneath Europa's frozen crust.
34:42Finding direct evidence of liquid water on Europa is terribly exciting.
34:47Finding liquid water is very important for finding biology.
34:50We don't know that wherever there's water, there's biology, but we're pretty sure that
34:54without it, it would be a lot tougher.
34:58For life to evolve, it needs water and other chemicals.
35:03And that's where Jupiter's magnetosphere comes in, the network that transports chemicals
35:09from volcanic moon Io to Europa.
35:13Scientists think this delivers sulfur, carbon, and other minerals, and that its radiation
35:19splits apart frozen water molecules on Europa's surface into hydrogen and oxygen.
35:29From a biology point of view, what's important is that there's interesting stuff being made
35:34on the surface, and if that stuff could get carried into the ocean, organisms might appreciate
35:39it.
35:41So Europa's geysers are a major discovery.
35:44One of the more exciting aspects of seeing this geyser on Europa is it means that the
35:49liquid ocean underneath the surface has a way of getting out, which means maybe there's
35:53a way of stuff from the surface getting into the ocean itself.
35:58It could be that in this ocean, there's a nutrient-rich supply of food.
36:06Life needs water, it needs food, and something else.
36:12You also need an energy source.
36:14On the Earth, mostly, that's the sun.
36:15It's light coming down and warming the surface.
36:18On Europa, though, if you're deep in that ocean, it's probably pitch black.
36:25But life can exist without the sun.
36:30If you go to the ocean floors on Earth, there are places where there are vents, cracks in
36:34the crust, and gases and all sorts of noxious chemicals are coming up.
36:38But there's life there.
36:40The notion that there could be this flow of nutrients from this subsurface into an oxygen-rich
36:46water and life living at this boundary between them, that's an example right in front of
36:52us of how an ecosystem could be shaped that way.
36:57Life evolves to match the conditions in which it finds itself.
37:01The conditions under the surface of Europa are very similar to the conditions at the
37:05bottom of the ocean here on Earth.
37:07We may find life there, and if we do, it may look quite a bit like life under the ocean
37:13here on Earth.
37:18If there is life beneath Europa's surface, it may outlive us all.
37:25This inhospitable world could become a last refuge for life in the solar system, because
37:35the sun is destined to die.
37:52Jupiter has left its mark on our solar system.
37:56The largest planet with the strongest gravity, it's shaped our past and influences our present
38:05but the planet's future hangs in the balance.
38:09The ultimate fate of Jupiter may rest on the fate of the sun, and in 4 to 5 billion years
38:15the sun will expand to become a red giant, perhaps eating up the Earth in the process.
38:22We think that the sun's outer layers are going to expand possibly even to the orbit of Mars.
38:27The Earth is possibly going to be engulfed and completely devoured by the expanding sun.
38:33When that happens, of course, it's game over for Earth.
38:39Five billion years from now, the inner rocky planets will burn up.
38:44Will Jupiter be next?
38:46From the perspective of somebody orbiting around Jupiter, the sun is going to turn into
38:50this angry, fiery thing, and yet Jupiter itself is probably going to be relatively safe.
38:57It may lose some of its atmosphere, but Jupiter's a big planet, it has plenty to spare.
39:02Eventually, the region of the Earth will become uninhabitable, but what's also equally
39:07clear is the regions we now think of as remote, far away, frozen, will become much more attractive.
39:17It'll be warmer, so its moons might actually warm up, and it has icy moons.
39:22Right now they're frozen water, but with the warm sun for millions or tens of millions
39:27of years, they may actually liquefy, and Europa may become basically a gigantic water
39:33droplet, a self-contained ocean orbiting Jupiter.
39:38It's an amazing thought.
39:42Perhaps Europa will be life's last, best refuge as the sun dies.
39:49As the sun evolves, will the moons of Jupiter, could it be that they become the
39:57prime places that we either travel to, or perhaps life once again begins?
40:06In our dying solar system, Jupiter's moons may offer a safe haven for life, but Jupiter's
40:14time in the sun is limited.
40:24After the sun undergoes its dramatic red giant phase, it's going to collapse down and end
40:28its life almost with a whimper.
40:30It will become a white dwarf.
40:35You wouldn't even be able to see the sun from the surface of Jupiter when the sun undergoes
40:40its final stage to become a piece of nuclear waste drifting in outer space.
40:47Jupiter and its moons will become dark once more.
40:53Once the sun evolves into a white dwarf, Jupiter will probably go largely unaffected.
40:58Our solar system and the evolution of the sun won't change its orbit very much.
41:01It's just going to keep trucking along and continue to orbit that old white dwarf for
41:06billions of years.
41:09Jupiter will live on, and with it, the hope of life.
41:14If there's life underneath the ice on Europa, somewhere in the ocean beneath the surface,
41:19it's possible that it could still continue, warmed by the tidal forces from Jupiter, even
41:25after the sun has met its end as a white dwarf.
41:29The thing is, Europa is already a shell of ice with liquid water that doesn't really
41:33need the energy from the sun.
41:36So if there's life there, it's not going to care whether the sun's alive or dead.
41:40They actually might outlive the sun itself.
41:45A billion years from now, Jupiter will take center stage.
41:54Jupiter determines, more than any other planet, how our solar system works.
41:59Much as a conductor governs the dynamics of an orchestra.
42:05Jupiter is the key to our solar system's success.
42:10We're talking about a planet that dominates the entire solar system, whose gravity determines
42:16the very structure of the solar system itself.
42:21A planet whose evolution helped to clean out the solar system.
42:27So we see that the past and the future depends on Jupiter.
42:33Jupiter has been here since the solar system's earliest days, and it'll be here at the end.
42:42Creator, protector, nurturer, and survivor, Jupiter shaped the solar system that we see
42:51today, and makes life possible on Earth, and perhaps beyond.
43:03NASA Jet Propulsion Laboratory, California Institute of Technology