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00:00Our universe is violent.
00:06The cosmos is full of planets from hell.
00:10What we have is a collection of monsters.
00:13Super hot worlds roasting at thousands of degrees.
00:19Frozen planets too cold for life.
00:23Desolate worlds seared by deadly radiation.
00:28Even planets where rock rains from the sky.
00:32We have hundreds and hundreds of these things we found and they're crazy.
00:38We search the heavens for worlds like our own
00:41and find planets where life could not possibly survive.
00:46How can the universe be so weird?
00:51Is the earth a one-off?
00:54Is the earth the only habitable planet in the universe?
01:00Or are there worlds like ours out there just waiting for us to find?
01:24Look out at the cosmos.
01:29Billions of galaxies.
01:37Trillions upon trillions of stars.
01:43And one profound question.
01:47Is anyone else out there?
01:51We want to find another earth.
01:53Is there a pale blue dot orbiting some star out there in the galaxy?
02:03The search is on for worlds that could harbor life.
02:08We're searching for our own vision of ourselves out there in space.
02:11We're searching for our heaven.
02:17We've already discovered more than 700 planets beyond our solar system.
02:26And yet these exoplanets look nothing like our own.
02:35Boy, were we wrong.
02:39All these solar systems that we're seeing in outer space,
02:42we find that they don't look like our solar system at all.
02:46We are the oddball. We're the freaks.
02:53These are nightmare worlds.
03:05And the cosmos is full of them.
03:09We're finding all different flavors of hell.
03:12All these different ways that planets can go wrong.
03:14So that's where we are right now.
03:16Searching for heaven, finding hell.
03:27These are worlds where life couldn't possibly survive.
03:36Could we really be alone?
03:39A cosmic fluke in a universe hostile to life.
03:44We may soon have the answer.
03:47Now we have discovered hundreds of exoplanets in outer space
03:51at the rate of over one exoplanet a week.
03:54In a few years, that will probably be thousands.
03:57And in the end, there could be millions or even billions of these things
04:01waiting for us to discover them.
04:04How could all of them be planets from hell?
04:09The quest for answers starts here, 63 light years from Earth.
04:19We've discovered a planet.
04:22It's even larger than Jupiter.
04:28And it has a serious problem.
04:37Its orbit is incredibly tight.
04:40It's closer to its star than Mercury is to our sun.
04:48And 30 times closer in than the Earth.
04:53The result is a superheated hell.
05:01But there's another reason why nothing could survive here.
05:14And that's the ferocious wind.
05:20The surface is battered by a never-ending storm.
05:33We can't see these winds with our telescopes.
05:41But we know this superstorm exists.
05:48Because of this.
05:52NASA's Spitzer Space Telescope.
05:56Spitzer can see things that we can't.
06:00It doesn't use visible light.
06:06Instead, it sees in infrared.
06:09It's a part of the light spectrum we don't see with our eyes.
06:13Infrared is heat.
06:19One advantage of studying the universe in infrared is it gives us this opportunity to see the light coming from planets around other stars.
06:27When you try to look at the light of a planet next to the light of a star, the star is hundreds of thousands of times brighter than that planet.
06:34Which renders the planet very, very faint.
06:37But if we push into the infrared part of the spectrum, the internal heat of the planet, just as my internal heat, causes the planet to glow.
06:47Now it's observable and measurable.
06:53Spitzer gives us something completely new.
06:56The very first weather map of a planet beyond our solar system.
07:03This simple image is a technological triumph.
07:10The colors represent temperature differences.
07:14But the map also proves the planet has hellish winds.
07:23That's because the hotspot isn't where it should be.
07:29One side of the planet permanently faces the star, so its center should be the hottest point on the planet.
07:38It isn't.
07:42Something pushes the planet's hotspot to the side.
07:47And that takes incredible force.
07:58Only a nonstop 6,000 mile an hour hurricane could be this powerful.
08:0920 times stronger than the strongest winds on Earth.
08:15Eight times the speed of sound.
08:22A small shift on a weather map.
08:28Evidence of supersonic winds raging on an alien planet.
08:38Truly, a planet from hell.
08:50We see new planets at a staggering rate, an average of one a week.
08:58Each one could be an Earth-like heaven.
09:04But the more we explore them, the more hellish worlds we find.
09:10And some are so nightmarishly hot that they're more than uninhabitable.
09:18They shouldn't even exist.
09:32This Jupiter-sized gas planet is 256 light years from Earth.
09:39In infrared, it shines like a star.
09:44Thousands of times brighter than Venus, the hottest planet in our solar system.
09:55It's a blistering 3,700 degrees.
10:04It's nearly impossible for a planet to get this hot.
10:16Its hellish temperature provides a clue to its appearance.
10:29Only an absolutely black object could absorb enough light from its star to reach such scorching temperatures.
10:40If you were coming up on the night side away from the star, you would just see this blackness in front of you.
10:45Very little radiation, very little light.
10:48It would almost just look like the stars were avoiding a part of the sky.
10:58But as black pavement absorbs sunlight and heats up on a sunny day, the black planet roasts beside its star.
11:10We don't understand its atmospheric chemistry.
11:14There's nothing on Earth that can absorb so much light.
11:24Its only color comes from a scorching hot spot.
11:29As you flew around to the day side, things would begin to glow red hot.
11:34There'd be a huge swirling storm, all red and glowing.
11:38What a hellish world.
11:46Deep inside, clouds of titanium oxide swirl around a solid heart 100 times heavier than Earth.
11:56Darkness visible, another world from hell.
12:05But some planets are even bigger, seemingly impossible puzzles.
12:13Here's a mystery.
12:14Every astronomy textbook says that gigantic Jupiter-sized planets form way out in outer space where it's really cold.
12:22So why is a Jupiter-sized planet, what's it doing inside the orbit of Mercury?
12:33Jupiter-type planets can only form far from their parent stars, out in the cold of space.
12:47A gas giant orbiting this close means these monsters can move.
12:57This is WASP-12b, a scorching vision of hell.
13:05It's so close to its star that its orbit lasts just one Earth day.
13:12This world is so hot it's over 4,000 degrees Fahrenheit.
13:15This is just crazy hot.
13:18WASP-12b is one of the hottest planets in our galaxy.
13:25We've never seen anything like this before.
13:28This certainly is one of the most violent environments in the universe.
13:38WASP-12b is only 2 million miles from its star.
13:44Searing heat puffs up its atmosphere, giving it the density of styrofoam.
13:52In a big enough bathtub, it would float.
13:56We actually think it's so close to its star that the gravity, the tidal effect of gravity, warps it into almost an egg shape.
14:03It's not even round, it's oblong.
14:10Thousands of miles beneath the puffed-up atmosphere lies a solid core.
14:18It's rich in carbon, and the pressures are extreme.
14:23There could be mountains of diamond and graphite, and seas of liquid tar.
14:39But WASP-12b won't last long.
14:44It orbits so closely that its star is literally tearing it apart, ripping away nearly 190 quadrillion tons of gas a year.
14:59Ten million years from now, WASP-12b will vanish.
15:15The question is, how did it get so close in the first place?
15:28This is the birth of a solar system.
15:32In the center, a new star.
15:40Around it swirls a disk of microscopic dust grains.
15:48These are planets in the making.
15:51Dust grains collide, and every time they collide, they merge, and so they get bigger and bigger,
15:57and so they sort of grow like the dust bunnies under your bed.
16:00And you have 100,000 years or a million years to make a very big dust bunny, and they get bigger and bigger and bigger.
16:14Trillions of miles from the star, it's cold enough for ice to form.
16:23Ice picks up dust and gas.
16:32These gaseous clumps grow bigger and bigger over millions of years.
16:38Eventually, they become gas giants.
16:45In our solar system, the gas giants Jupiter, Saturn, Neptune, and Uranus all form this way,
16:55in the distant orbits we still see today.
17:02So how did WASP-12b end up so searingly close to its star?
17:10The answer? Gravity.
17:14This planet is huge, 40% more massive than Jupiter.
17:25Its immense gravity disturbs the dust disk it formed from, creating turbulence.
17:37And so the planet creates waves in the disk, you know, sort of density waves,
17:42and you can sort of think of them as like waves on an ocean.
17:46The gas giant becomes a galactic surfer.
17:52For hundreds of thousands of years, the planet rides the waves inward toward the star.
18:02As the planet gets closer and closer to the star, it starts to feel the radiation from the star more and more, and so it heats up.
18:11Surfing millions of miles from the cold outer reaches of the star system
18:19into the tight, scorching orbit we see today,
18:25an ice-cold world becomes a planet from hell.
18:32Nobody had any real clue that you could form a planet a billion miles out from a star.
18:37It somehow moved in. That is incredible.
18:40But that's really the only explanation of how these planets got so close to their stars in the first place.
18:50WASP-12b is bizarre, but it isn't alone.
19:02We've found many of these super-hot, super-close giants.
19:08We call them hot Jupiters.
19:16Battered by supersonic winds.
19:20Blacker than night.
19:23Hotter than hell.
19:29But these hot Jupiters all have one thing in common.
19:36There's no life here.
19:40So these planets are just about as different from the Earth as you can possibly imagine.
19:44In fact, we've now found over a hundred of these things, rendering them so common
19:50that the question really emerges, which ones are the weirdos, them or us?
19:58This planetary roller coaster has consequences.
20:02As they spiral inward, hot Jupiters cause chaos.
20:06They create a whole new class of planets from hell.
20:11Orphan worlds flung away from their star
20:16into the emptiness of interstellar space.
20:29Planets orbit stars.
20:36Between the stars is a vast sea of darkness.
20:42We've always thought of space as being empty.
20:44That would be considered its defining characteristic.
20:47That's why we call it space.
20:49But when planet hunters switched from gazing at stars to staring deep into space,
20:58they made an amazing discovery.
21:05Out of the darkness, between the stars, planets began to appear.
21:11First, one dark gas giant.
21:19Then several more.
21:28Eventually, ten dark, starless planets emerged from the shadows of space.
21:40I often wonder what it would be like to be on one of these rogue planets in between stars.
21:46The night sky would be perfectly black.
21:49It'd be festooned with stars. It'd be beautiful.
21:54But if you were at one of these planets, you would be in a world of perpetual night.
21:59There would be no sunrise or sunset.
22:01There would be no warmth of the sun.
22:05These planets formed around a star.
22:09But now they roam the darkness of interstellar space.
22:15Their journey here was violent.
22:18Each one forced from its home orbit by the gravity of a hot Jupiter.
22:31A Jupiter-sized planet is an 800-pound gorilla.
22:35Where does it sit? Anywhere it wants to.
22:42Hot Jupiters are killers.
22:48As they surf in toward their star, their immense gravity disrupts the system,
23:00repelling planets from their orbital paths.
23:04It flings into outer space any small planet.
23:08So any planet unfortunate enough to be orbiting close to the mother star
23:13would be flung into outer space with a passing Jupiter.
23:25These planets will never again feel the heat or see the light of a star.
23:34All the rogue planets we've found so far are gas giants.
23:38But perhaps there are smaller, rocky worlds too.
23:49Worlds that were once like Earth.
23:54The large Jupiter-like planets are just easier to see,
23:57but there's no reason to assume there also aren't smaller orphan planets.
24:01Maybe as a Jupiter planet moves in toward the star and plays ping-pong with the planets,
24:05even something like Earth could have gotten kicked out.
24:08Then you would have this cold, frozen little world,
24:11just streaking between the stars, dark and lonely.
24:17These planets are victims of a violent gravitational battle.
24:22Frozen, orphaned Earth twins.
24:27There may be hundreds of billions with a B of these planets roaming the galaxy.
24:33Now there are only a couple of hundred billion stars in the galaxy,
24:37so that means these rogue planets may actually outnumber stars.
24:46Right now, we find an average of at least one new exoplanet a week.
24:52As our technology improves, we'll see smaller and smaller planets orbiting stars.
24:59Worlds with a solid surface like our own.
25:04But the first rocky planets we've found are nothing like Earth.
25:09These planets have been to hell and back.
25:27We have found hundreds of alien worlds.
25:33And now for the first time, we're finding small planets made of rock, just like Earth.
25:47Planets this size are potential homes for life.
25:56But instead we find more planets from hell.
26:01Weird, nightmarish, and uninhabitable.
26:19This is Coro 7b.
26:26A world of violent extremes.
26:32Two hells in one.
26:37It's so close in that its star looms 360 times larger in the sky than our sun.
26:48On Coro 7b, the first hell is unimaginably hot.
26:55The surface is a furnace, roasting at 4700 degrees.
27:03Lava boils, turning the atmosphere into vaporized rock.
27:10When a cooler front moves in, small pebbles condense.
27:16And rocks rain from the sky.
27:20If that's not a classic vision of hell, I don't know what is.
27:25But that's only half the story.
27:31The hot side of the planet is locked, permanently facing the star.
27:40Beyond is the twilight zone.
27:46It's temperate here.
27:51Cool enough to turn the lava oceans into solid rock.
28:00But this pleasant zone is narrow.
28:05Travel further, and you descend into a second hell.
28:12This is the dark side.
28:20The half of the planet that never sees the sun.
28:26Eternal darkness and savage cold.
28:32The temperature is hundreds of degrees below zero.
28:39So one side is hot, another side is cold.
28:44You either have fire or ice in the extreme, the coldest places in the universe and the hottest places in the universe.
28:49You couldn't think of a worse place to end up.
28:56The planet was not always this way.
29:01Turn back the clock 1.5 billion years.
29:07A new galaxy is forming.
29:12But it isn't rocky.
29:15It's a gas giant.
29:19A hundred times bigger than Earth.
29:25It migrates in toward its star.
29:30As it closes in, the star blowtorches gas from the planet.
29:38Its gaseous shell blasts off into space to reveal a rocky core.
29:49Coro-7b is the skeletal remains of a hot Jupiter.
29:55Its parent star has reduced this once massive gas giant to a rocky cinder.
30:08It's hard to imagine planets more extreme than Coro-7b.
30:16Yet they do exist.
30:21Rocky Worlds. Machine gunned by deadly cosmic rays.
30:38This is a pulsar 7,000 trillion miles away from Earth.
30:49It's a kind of cosmic lighthouse.
30:55This unbelievably tiny world, just 10 miles across, fires an intense beam of radiation through space
31:04as regularly as an atomic clock.
31:10A single cubic centimeter, the size of a keyboard key, actually has about as much mass as Mount Everest.
31:16Smash a Mount Everest into a cubic centimeter, the whole star, which is only about 10 miles across, is like that.
31:24It's one of the most hostile environments in the universe.
31:30Anything nearby gets hammered by intense gravity and magnetism.
31:38No one expected to find a planet here.
31:44But this pulsar has three.
31:50Small, rocky, near-Earth-sized.
31:56And the last place you would ever find life.
32:02It's got a tremendous magnetic field. It's blasting out X-rays.
32:06So these poor planets are just getting cooked by radiation.
32:10The word Earth-like I don't think could be applied to these guys at all.
32:16The X-ray beam strafes the planets over and over,
32:22firing radiation a million times more deadly than medical X-rays,
32:31slowly stripping their surfaces away.
32:37These are sterile worlds.
32:42Everybody admits there's no chance for life, at least as we know it, on the planets that orbit the pulsar.
32:50Radiation cooks pulsar planets to death.
33:00The opposite hell is no better. Frozen worlds too cold for life.
33:10In the constellation Scorpius, 20,000 light-years away, is a red dwarf star.
33:21Red dwarfs are tiny and relatively cool.
33:36And this planet is too far away to fill what little heat there is.
33:42It's so distant, its orbit lasts 10 Earth-years.
33:49It's the coldest planet we have found in the universe.
33:58Its surface is a frigid 370 degrees below zero.
34:05This is a world made entirely of ice.
34:11Methane, ammonia and nitrogen are gases on Earth.
34:17Here they form a frozen, toxic frost.
34:23Glaciers and canyons and cliffs of ice are the only terrain.
34:31Here, hell really has frozen over.
34:38Our search for Earth's elusive twin reaches another dead end.
34:48Perhaps we are truly alone.
34:56Or will our first tantalizing glimpses of an alien world, potentially perfect for life, change everything?
35:08NASA Jet Propulsion Laboratory, California Institute of Technology
35:19Earth. The only habitable world in our solar system.
35:27But in a galaxy of hundreds of billions of stars, can we really be alone?
35:38It's a question that planet hunters are trying to answer.
35:45The whole purpose, in my opinion, of the discovery of exoplanets
35:51is to establish our true place in the universe.
35:57Who are we? Where do we belong in the cosmic scheme of things?
36:04That's where NASA's Kepler Space Telescope comes in.
36:10Kepler lets us calculate how far a planet is from its star.
36:16That's critical in figuring out whether it could sustain life.
36:22Life on Earth is only possible because we're the perfect distance from the sun.
36:28And not too cold.
36:33Just right for liquid water.
36:37Oceans, rivers, lakes, rain, and life.
36:46You know, journalists say, follow the money. Astronomers say, follow the water.
36:52Because water is the universal solvent that dissolves most chemicals
36:56and that's where DNA got off the ground.
37:00And where there's liquid water, there could be life.
37:05We're looking for planets that are not too close to their parent star,
37:09where all the water would boil away, and not too far away from their parent star,
37:13where all the water would be tied up in a frozen form.
37:16We're looking for that Goldilocks zone, where the temperatures are just right
37:19for liquid water to pool on the surface.
37:25Once Kepler has identified a new planet, astronomers check whether it lies
37:31in the habitable zone of its parent star.
37:35So far, Kepler hasn't found a single confirmed Earth twin.
37:42But it has identified more than 2,000 planetary possibilities.
37:49And it's this sheer abundance of planets that gives scientists hope.
37:55The important thing to remember is that even though we're finding all of these
37:59terrible planets that are just completely unlivable,
38:02is that we're finding lots of them.
38:05We're finding hundreds and thousands of these planets.
38:08And what that's telling us is that planets are easy to make.
38:12And that means that even rare things are probably out there in large numbers.
38:18Even if the Earth is a rare, precious jewel in our galaxy,
38:22there may be dozens or hundreds of them out there.
38:30Kepler has opened our eyes to a universe full of planets.
38:35We can now guess at how many there might be in our own galaxy.
38:4250 billion.
38:4850 billion worlds just waiting to be discovered.
38:53And we think 1% could be in the Goldilocks zone of their star.
39:06That's 500 million planets, each with a chance of harboring life.
39:14Right here on our own doorstep.
39:24We haven't found one yet, but we're getting closer.
39:30This is Gliese 581, a red dwarf star 20 light years from Earth.
39:37Gliese 581 is a tiny little star.
39:40If the Sun were the brightness of about a 100 watt light bulb,
39:43then Gliese 581 would be like a little Christmas tree light,
39:46a tiny little fairy light, very, very small.
39:49This shifts the life zone in, because now if you want to be warm enough,
39:53you need to snuggle up right next to the star.
39:57The star has four planets.
40:02Three are too close and hot for liquid water.
40:07But the fourth is different.
40:12It's a rocky world twice the size of Earth.
40:17And it's a rocky world where the sun is the brightest.
40:21It's a rocky world twice the size of Earth.
40:26And it's right on the edge of the Goldilocks zone.
40:37In theory, if the planet has a thick carbon dioxide atmosphere,
40:42it could trap enough heat to have clouds,
40:47rain and oceans.
40:51It would be a strange place to live,
40:54twice Earth's gravity,
40:57bathed in permanent red twilight.
41:07But right now, this weird world is the closest we have to a planet like ours.
41:15It's a promising start.
41:18When we actually know for a fact
41:21that up there around that star is a planet like Earth,
41:25that's going to just fundamentally change how people look at the sky
41:28and how people perceive their place in the universe.
41:31So that's going to be a profound moment,
41:33not just for me, but I think for humanity in general.
41:40Our goal is to find another Earth,
41:42but along that path we are going to find more things
41:46than we could have ever possibly imagined.
41:48And that's the part I love about this the most.
41:51We don't know what craziness is going to be around the next corner
41:54when we're looking for more planets.
41:56I can't even imagine.
42:05Two decades ago, the only planets we knew
42:08were right here in our solar system.
42:12Now, there are hundreds,
42:15all very different from our home.
42:22The universe is filled with hellish worlds.
42:27Super hot.
42:31Ultra cold.
42:35Violent.
42:41And bizarre.
42:47But the universe is also unimaginably vast.
42:53With so many stars,
42:55there are probably countless Earth-like heavens.
42:58All we have to do now is find them.