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00:00The Earth is in danger. Future cosmic events will blast, burn, or rip us to shreds.
00:10The universe is incredibly violent. There are huge events going on all the time.
00:16One day, life on Earth will become impossible.
00:19There will be disasters in the future, and one of them will destroy us.
00:25To save mankind, we'll need to find other places to call home.
00:31It really has to be our destiny to move off the Earth if we are going to survive. It's as simple as that.
00:38We need an insurance policy.
00:41We must do it, and we must get started now.
00:43We'll need a lifeboat and new homes amongst the stars.
00:49This is how we can do it.
00:54The Earth. As far as we know, it's the only home to life in the universe.
01:13Earth is such an ideal environment for life.
01:17Everything about our bodies, our biology, our chemistry evolved here on Earth.
01:23We literally are on the perfect spaceship.
01:28But our perfect spaceship is hurtling through a cosmic minefield.
01:35Every 30 million years or so, a natural or cosmic disaster hits the Earth so hard that millions of creatures go extinct.
01:46Extinction events tend to kill off the dominant species.
01:54And right now, that's us.
01:59It's certainly true that in an extinction event, it's the large and powerful that get wiped out. They go.
02:06So you know that if there's an extinction event on Earth, we humans are vulnerable.
02:10We're in the category of large and powerful.
02:13The only way for humankind to survive global extinction is to spread our genes to more than one planet.
02:21We have no choice. It's a law of evolution, geology, and physics.
02:27The alternative is death and extinction.
02:32We'll have to build a giant spacecraft capable of crossing interstellar space.
02:38You will essentially need a new Noah's Ark.
02:42But it's going to be a space ark, and it has to encapsulate all of the diversity of Earth inside this one ship.
02:50The space ark will have to be huge, big enough to house the thousands of people needed to create a healthy planet.
02:59Too massive to construct on Earth, the giant craft will have to be built in space, far from the pull of Earth's gravity.
03:07But building a shipyard in the sky is no small challenge.
03:14NASA is tackling the challenge of building a giant spacecraft capable of crossing interstellar space.
03:21Building a shipyard in the sky is no small challenge.
03:27NASA is tackling it head-on with a new generation of heavy lift rockets called SLS.
03:37I see the SLS as a capability that's going to allow us to put an industrial base between the Earth and the Moon.
03:43After we do that, and we're out there routinely working in space, that's when we'll assemble the craft that will take us to the stars.
03:52Les Johnson's job is to plan the future of space exploration.
03:59Today, he's observing a test firing of a 1-20th scale model of SLS.
04:05When the real deal takes off in 2032, the SLS will become the most powerful rocket ever launched.
04:15The SLS is big. It's going to give us a capability to take lots of stuff up with each launch.
04:20And it can be big volume.
04:21And you could potentially launch three of these big rockets versus perhaps 15 or 20 of the other rockets we have available today to get the same amount of material out into space.
04:32Les envisions SLS rockets taking prefabricated units beyond Earth's orbit, where space engineers will assemble them in a colossal industrial workshop.
04:44Miners will then fly out to different bodies in the solar system to collect the raw materials needed to build the space ark.
04:53We'll have factories on the Moon, and perhaps even beyond that, on giant rocks inside the asteroid belt.
05:02Asteroids have a fraction of Earth's gravity.
05:05Here, it will be much easier to build massive sections and lift them to the ark as it begins to take shape.
05:14The inner solar system will provide all we need to make the giant superstructure of the space ark.
05:23But to colonize a different world will require a propulsion system faster than anything we've ever built before.
05:32Space is huge. Our solar system is huge. Even to get to Mars would take almost a year.
05:36But that's nothing compared to exploring the distance between stars.
05:42The nearest stars to our sun are several light years away.
05:45Even light, the fastest thing in the universe, takes several years to get there.
05:50The sun's closest neighbor is a triple star system called Alpha Centauri.
05:57A spaceship burning conventional fuel would take tens of thousands of years to get there.
06:03The crew would die of old age long before the ship arrived.
06:08So what fuel to use?
06:13Science fiction appears to have the solution, but it sounds too good to be true.
06:20Every Trekkie in their heart of hearts knows that it's antimatter.
06:23Antimatter is the fuel for an interstellar ship.
06:31Antimatter is real.
06:33We create a few atoms of antimatter every year in high-energy particle colliders.
06:40It's a mirror image of all the matter that we see around us.
06:44And it has an explosive property that would make it the most efficient rocket fuel ever created.
06:51Here's the cool thing about antimatter.
06:53When antimatter and matter meet, they annihilate each other.
06:59That means that the matter ceases to exist.
07:04They convert into pure energy.
07:08It's a 100% efficient process.
07:12Scientists have calculated that a rocket powered by antimatter could reach 15% of the speed of light.
07:20That's fast enough to get to the moon in eight and a half seconds.
07:25We will have almost unlimited power. We could travel anywhere in the universe we wanted to.
07:31Our space ark could reach Alpha Centauri in just over 28 years.
07:37Well within the lifetime of its human payload.
07:41Now this sounds like a great idea, right?
07:43Let's get together a lot of antimatter. Let's create some antimatter.
07:46And let's combine it with regular matter and we have this outstanding energy source.
07:51But antimatter has a huge problem.
07:54And that is exactly what its advantage is.
07:57When it meets matter, it's going to annihilate and create energy.
08:02Fill a conventional fuel tank with a single pound of antimatter.
08:06And you'll get an explosion more powerful than a thousand Hiroshima bombs.
08:13Antimatter is just too hot to handle.
08:17We need a reliable energy source that can power our starships for years at a time.
08:24And there are only a few candidates that can do this.
08:26Among them, fusion power, harnessing the power of the sun itself.
08:36In the sun's hot, dense core, hydrogen atoms collide.
08:43Smashing into each other with such force, they fuse, releasing enormous amounts of energy.
08:49This is nuclear fusion.
08:56What we want to do in space travel is miniaturize it and put it in a spacecraft
09:00and use that as your power system and as your propulsion system for deep space exploration.
09:09A fusion rocket is still two-thirds the speed of one powered by antimatter.
09:14And best of all, its fuel, hydrogen gas, can be found in vast clouds between stars.
09:22It would simply automatically fire in outer space using interstellar gas.
09:28And in principle, it would never require refueling.
09:32Our fusion-powered space ark heads for its first target, Alpha Centauri,
09:38at 10% the speed of light.
09:41It will take 42 years to complete the journey,
09:45and its precious load of human pioneers must be delivered safe and well.
09:51But the crossing may be deadly.
09:54Our violent cosmos has a million ways to kill.
10:09A giant space ark fires its fusion rockets.
10:14Inside the ship are thousands of human volunteers.
10:18They're on a one-way mission to colonize a distant planet.
10:23We will one day have to make this journey.
10:28It's inevitable that we go off planet.
10:30I think we're going to have to do it to survive as a species.
10:33The ark's first target is the closest star system to the sun, Alpha Centauri.
10:39And the journey will be long, around 40 years.
10:43Keeping the crew fit and healthy is imperative.
10:47But it won't be easy.
10:49A lot of things happen to the human body when you go into space.
10:53The moment you become weightless, you instantly get kind of a shock.
10:56You get dizzy. That can make you feel nauseous.
11:00Leroy Chao spent six months on the International Space Station,
11:04long enough to experience the damaging effects of zero gravity.
11:10Your bones aren't feeling any impact, so your body decides it doesn't need bones anymore,
11:14and it'll begin to demineralize your bones.
11:16And it'll begin to demineralize your skin.
11:18It'll begin to demineralize your skin.
11:20It'll begin to demineralize your skin.
11:22And then your muscles, through disuse, of course, they'll naturally atrophy very quickly.
11:29The human body evolved to live with Earth's gravity.
11:33Without it, bones lose 2% of their mass for every month spent in space.
11:40The cardiovascular system suffers, too.
11:44Body fluids become less and less.
11:47The cardiovascular system suffers, too.
11:51Body fluids pool.
11:54Heart rates and blood pressures rise.
11:58Resistance training helps reduce the symptoms.
12:02We're scheduled for two hours of exercise a day on the space station
12:05to keep our cardiovascular system fit, to keep our muscles and our bones fit.
12:10Exercise can hold off the dangerous wasting process.
12:15But a 42-year journey to Alpha Centauri without gravity would be fatal.
12:23Obviously, we need a permanent solution to weightlessness.
12:28There's nothing to prevent us in the near future from creating artificial gravity.
12:36Centrifugal force is the answer.
12:40It's the force that sticks daredevil bikers to vertical walls
12:44and keeps thrill-seekers glued to their seats in theme parks.
12:50Rotation produces this outward force,
12:53and it would be relatively simple to create in a spaceship.
12:59By rotating a space capsule,
13:02it means that the astronauts inside will experience artificial gravity.
13:06Spinning the living quarters at just the right speed
13:09will hold off bone and muscle wasting.
13:13But low gravity is the least of the dangers our pioneers will face
13:18as they journey deep into space.
13:21Radiation is probably the biggest challenge.
13:24We're going to be exposed to much harsher levels, much higher levels of radiation.
13:29The space station is the only space station in the world
13:34The sun's surface shoots out a constant stream of dangerous charged particles,
13:38protons and electrons,
13:41traveling at close to a million miles per hour.
13:45These things will break your DNA,
13:48they'll cause cancer,
13:51and they will kill you.
13:54The Earth's magnusphere and the atmosphere above our heads
13:57protects us from the worst of this radiation.
14:00But far from the Earth,
14:03the pioneers will face radiation head-on.
14:06That really is the biggest technical barrier
14:09to mankind sending people out farther and deeper into space.
14:13It's not propulsion, it's not computers or navigation,
14:16it's how do we keep people healthy.
14:19Beyond the boundary of our solar system,
14:22the radiation threat gets worse.
14:25Charged particles come at you even faster.
14:29In some cases there are single protons
14:32that actually pack as much of a punch
14:35as a hundred mile an hour fastball.
14:38These cosmic rays are joined by an even deadlier force,
14:42gamma rays spewed out by violent cosmic events.
14:47All of the cosmic phenomena,
14:50from stars exploding
14:54to black holes eating up large parts of galaxies,
14:59produce radiation and particles that are incredibly energetic.
15:05You've never seen these particles before,
15:08your body's not adapted to them.
15:11And they come at you all the time, and they're very high energy.
15:15Galactic cosmic radiation will rip through the cells of our human cargo,
15:19liquefying their bodies.
15:24The only hope is to somehow shield the spacecraft.
15:27In science fiction,
15:30starships create a protective magnetic bubble
15:33similar to the magnetic field that protects the Earth.
15:36But a deflector shield
15:39would take a huge amount of energy to sustain.
15:42And, like any electrical device,
15:45it would be prone to failure.
15:48The safest option would be to build a shield
15:52The safest option is to go low-tech,
15:55coating the ship with a thick layer of physical shielding.
15:59Shielding is not a simple problem.
16:02It's not just a matter of bringing a bunch of lead or anything like that.
16:05In fact, what you find is that if you do something like that,
16:08it absorbs the radiation and then it re-emits it in a more dangerous form.
16:15Metals won't work,
16:18but scientists have come up with a brilliant alternative.
16:25In fact, one of the best shields from cosmic rays is something simple,
16:28water.
16:31And it's actually something you need to bring with you
16:34as you venture into interstellar space.
16:37The hydrogen atoms in water absorb high energy particles,
16:40and in sufficient volume,
16:43water can also block gamma rays.
16:46The living quarters of the ark will have a thick outer skin
16:49filled with the ship's water,
16:52and outside that, a second skin
16:55filled with the ship's hydrogen supply for its fusion engines.
17:01Our astronauts are now safe from radiation sickness,
17:04and with artificial gravity,
17:07their bodies will stay strong.
17:10The deadliest threat now is their crewmates.
17:16A cosmic catastrophe
17:19will one day wipe us from the face of the Earth.
17:22To save mankind,
17:25we'll need to escape to the stars
17:28in a giant space ark
17:31in search of new homes.
17:34Its precious human cargo
17:37will be kept in top physical condition
17:40with artificial gravity
17:43and hydrogen-rich shielding.
17:46But what about their mental health?
17:49One of the biggest challenges for people in space are the people.
17:52Taking people, putting them in a tin can
17:55in an incredibly dangerous environment,
17:58having them get along with each other for months or years
18:01and stay alive through the journey
18:04is going to be an enormous challenge.
18:07We know when people go on submarines
18:10that they have to be very carefully tested,
18:13and those submarines go out for missions
18:16that certainly don't last years.
18:19We can't start a new civilization
18:22with a crew ravaged by cosmic boredom,
18:25infighting and mental illness.
18:28It would help if the entire crew were unconscious.
18:31One possibility,
18:34which of course again is a possibility in science fiction,
18:37is to have people be asleep during most of it.
18:40Could you put people into an induced coma
18:43and then wake them up in time to go do their science mission?
18:46It might be an easier thing to do than to say,
18:49well, now you just sit still for the next 10 years.
18:52The closest we come to suspended animation
18:55in today's world is storing human embryos
18:58in liquid nitrogen.
19:01But could we really save the human race
19:04with test tube babies?
19:07Because of the enormous hurdles facing space travel,
19:10some people have advanced the idea,
19:13well, why do we have to send humans into outer space?
19:16Why not send embryos or sperm and egg cells?
19:19In theory, we could transport frozen embryos
19:22across the vast distances of space,
19:25sidestepping the need for food
19:28or complex life support systems.
19:31They could withstand the rigors of space travel
19:34and weightlessness, but how would they be socialized?
19:37You put a baby in a single place alone,
19:40they don't know how to read, they wouldn't survive.
19:43In fact, we're very dependent. We are social beings.
19:46We would have to develop intelligent robots
19:49to hatch the embryos and then teach them to be human.
19:54It's conceivable that perhaps 100 years into the future,
19:57we will have robot nannies
20:00that incorporate the laws of social interaction.
20:03Could a robot really raise a child?
20:06Or in our rush to save humanity,
20:09will we end up forgetting what it means to be human?
20:15Raising human embryos may be too much of a gamble,
20:18so could we freeze adults instead
20:21without affecting their health?
20:24It's a much bigger challenge,
20:27but nature has almost solved it.
20:30A lot of animals on Earth will go into suspended animation
20:33or hibernation when conditions get bad,
20:36and in some cases, they can stay that way for a long time.
20:41The Alaskan wood frog survives
20:44whole winters frozen in ice.
20:49At sub-zero temperatures,
20:52its metabolism slows and effectively shuts down.
20:58When the ice thaws,
21:01the frogs reanimate
21:04and hop off as though nothing happened.
21:07Could humans ever do the same thing?
21:11When you freeze somebody alive,
21:14there are ice crystals which form
21:17which begin to expand, rupturing the cells
21:20and turn cells into mush.
21:23So how do the frogs survive the deep freeze?
21:26The answer is,
21:29they have an antifreeze in their blood,
21:32and that is glucose.
21:35So even though their surrounding environment is solid ice,
21:38inside, their cells are liquid.
21:41The problem with humans is,
21:44that amount of antifreeze would kill us.
21:47Deep freezing humans isn't going to work.
21:50But we may not have to chill that low
21:53to hibernate.
21:56In Pittsburgh, surgeons have developed
21:59a ground-breaking technique
22:02using chilled saline solution
22:05to rapidly lower their patients' body temperature
22:08to just a few degrees above freezing.
22:11At this temperature,
22:14cellular activity stops.
22:17Just like the wood frogs,
22:20the patients are effectively
22:23in suspended animation.
22:26We can, in operating rooms,
22:29we can cool people down
22:32and put them in an artificial coma for a while.
22:35So it sounds good,
22:38and like everything else, it's worth exploring.
22:41Whether through freezing embryos
22:44or putting adults into a cold, deep sleep,
22:47suspended animation may be the best bet
22:50for keeping our precious human cargo alive
22:53on the long trip to Alpha Centauri.
22:56But what if they get there,
22:59and there's no place like home?
23:09A spaceship
23:12filled with human volunteers
23:15approaches the triple star system
23:18Alpha Centauri.
23:21The crew hopes to find the first
23:24of many new worlds for mankind to call home.
23:27But which, if any, of these stars
23:30will have the right kind of planets?
23:33We want to find a home that has
23:36similar to Earth as we can possibly find
23:39because we're fine-tuned for this planet.
23:42We're fine-tuned for this surface gravity.
23:45We're fine-tuned for this atmosphere,
23:48this radiation environment.
23:51The stars fill the spacecraft's displays,
23:54and soon the outline of planets will be visible.
23:57The brightest of the trio
24:00is Alpha Centauri A.
24:03It's slightly bigger and slightly brighter
24:06than our Sun, throwing more heat
24:09into the space around it.
24:13Its smaller, cooler neighbor,
24:16Alpha Centauri B, lies so close,
24:19gravity pulls the two stars
24:22into a wide, slow binary orbit,
24:25rotating once every 80 years.
24:28That's bad news for our pioneers.
24:34Planets rarely form stable orbits
24:37around wide binary systems,
24:40so there's little chance of finding
24:43a place to settle here.
24:48But the third star in the trio
24:51offers hope.
24:54Proxima Centauri is a red dwarf,
24:57or M dwarf star, too small and dim
25:01to be seen from Earth with the naked eye.
25:04Yet astronomers have found Earth-like planets
25:07around this type of star throughout
25:10the Milky Way galaxy.
25:13We're finding that red dwarfs are ideal
25:16in a number of ways. In particular,
25:19they seem to be absolutely teeming
25:22with Earth-sized planets.
25:25Astronomers have already discovered
25:28Proxima Centauri. It orbits too close
25:31to the star to sustain human life,
25:34but there's a good chance it may have
25:37a sister planet that can.
25:40If we were to look up into the night sky
25:43and look at the nearest M dwarf star,
25:46say Proxima Centauri, I would expect
25:49to see a system of three to six
25:52very small planets in extremely compact
25:55systems.
25:58Proxima Centauri may well be home
26:01to a rocky planet ideal for life,
26:04with a thick atmosphere, warm liquid oceans,
26:07and a strong magnetosphere to protect it.
26:10The perfect refuge for mankind
26:13to set up our first new home.
26:16But what if we find a planet
26:19that's a little less than perfect?
26:22Too cold, perhaps?
26:25With too much gravity?
26:28Or maybe the wrong kind of atmosphere?
26:31We are genetically programmed
26:34to thrive on the planet Earth
26:37with a specific amount of oxygen,
26:40a specific amount of carbon dioxide
26:43in a certain weight. However,
26:46once we land on a distant planet,
26:49what happens?
26:52We're going to have to be able to engineer ourselves.
26:55We're going to have to be able to evolve ourselves rapidly.
26:58That may mean taking genes from other life forms
27:01to give ourselves some property that we need.
27:04That might just be the best solution.
27:07Scientists have searched high and low
27:10to find the ultimate genes for survival in space.
27:13And they may have found them in a creature
27:16called Tardigrades.
27:19Right now at NASA, we're doing experiments
27:22on tiny little animals called Tardigrades.
27:25Tardigrades are tough.
27:28They can survive a range of temperatures
27:31from freezing to boiling point.
27:34They can live without food or water
27:37for a decade or more. And, crucially,
27:40when their DNA gets damaged by radiation,
27:43a tiny little microscopic thing can survive more radiation
27:46than would kill a herd of elephants.
27:49Somehow the DNA knows how to repair itself.
27:52We're trying to figure out how we could modify human DNA
27:55to do the same thing.
27:58One day, DNA from these tiny creatures
28:01may allow us to set foot on a planet
28:04battered by radiation from its parent star.
28:07And genetic tinkering may hold the key
28:10to much more, allowing us to colonize
28:13a multitude of hostile alien worlds.
28:19If the planet has a larger gravitational field,
28:22we may have to increase the strength of our bones
28:25and the strength of our muscles so we don't collapse
28:28every time we walk on the surface of a large planet.
28:35We could even adapt to different atmospheres.
28:39If we were to arrive on a planet that has a different oxygen level,
28:42different carbon dioxide level,
28:45we may have to alter our metabolism rate.
28:48We are beginning to take control of our own evolution.
28:51We are designing gene therapies.
28:54We are finding ways to modify our biology.
28:57There's a wonderful chance here to really take control
29:00of our own destiny and drive ourselves to the stars.
29:04Who knows what the future astronaut will look like,
29:07but I strongly suspect that they won't look like you or me.
29:13If we find habitable worlds around Proxima Centauri,
29:17a shuttle full of genetically altered pioneers
29:20will be dispatched to the surface
29:23in order to start a new human civilization.
29:28But this is just the first stage of a much bigger plan.
29:32We must continue to yet more worlds,
29:35traveling deeper and faster into the Milky Way.
29:39...
29:59One day, a cosmic event will hit the Earth so hard
30:02it will wipe out every human on the planet.
30:05If we're going to live on it definitely into the future.
30:08and definitely into the future,
30:09human beings are gonna have to leave planet Earth.
30:12Our only hope is to build a space ark
30:15that will take us to new worlds around distant stars.
30:20Life is fragile, and that's why I believe
30:23we should be at least a two-planet species.
30:29The first target was by far the easiest.
30:32It took 42 years for our space ark
30:39to reach Proxima Centauri using fusion-powered engines.
30:44But now the ark must move on to find even more distant worlds.
30:49The crew can be held in suspended animation,
30:53but they'll still deteriorate with each passing year.
30:56We need to go faster, closer to the speed of light.
31:01But there's a small problem, the laws of physics.
31:07What Albert Einstein figured out is that if you start
31:09traveling near the speed of light,
31:11things get a little bizarre.
31:15As you get near the speed of light, your mass increases,
31:18meaning that you have to have more energy to keep you going.
31:22By the time you get to near the speed of light,
31:24all the fuel turns into increasing the mass.
31:27So all the fuel that before would have increased the speed
31:29a lot doesn't increase the speed at all.
31:31It just increases the mass.
31:33Eventually, you don't speed up at all.
31:35You just get heavier and heavier as you shoot out propellant.
31:40Physics won't let us travel through space
31:42at the kind of speeds we need.
31:45But there's a loophole that may allow
31:46us to cut through hyperspace and reach distant planets
31:50a whole lot faster.
31:52Einstein showed us that space itself
31:55can expand faster than the speed of light.
31:58Space and time is not nothing.
32:00There's a substance to it, a fabric, if you will.
32:04And you can stretch it, and you can bend it.
32:07In science fiction, galactic travelers
32:10manipulate the fabric of spacetime using warp drives,
32:15crossing the cosmos in minutes, not millennia.
32:20Imagine you're in a room, and there's a carpet.
32:22And you need to get to the other side of the room.
32:24One thing you can do is you can take the carpet
32:26and fold it up and bring all of it close to you,
32:30then step over the folded carpet,
32:31and then let it unfold behind you.
32:33And now you've moved across the room really quickly.
32:36It would take a colossal amount of energy
32:39to warp all the space between you and your destination,
32:43far more than we could ever hope to generate.
32:46But modern physics says the warp drive
32:49is possible if you only warp the space surrounding the ship.
32:53So we know that space expands, and space
32:56can also contract.
32:57So if you have a ship, and you contract space in front of you
33:01and expand space behind you, you can create a warp bubble.
33:04And it's been theoretically shown
33:06that you can move to up to 10 times the speed of light.
33:11This new generation warp drive creates
33:14a wave in spacetime that travels faster
33:17than the speed of light, carrying the ship along
33:20with it like a surfer riding a wave.
33:25Mathematicians have looked at the numbers,
33:27and a new generation warp drive would work on paper.
33:31And now NASA wants to try it in the lab.
33:37Is it impossible, or is it plausible?
33:39I think we're in that category of starting to think about,
33:42we've got some plausibilities here.
33:44Let's go see if we can't do some scientific efforts
33:47and see validation of the math and physics.
33:52Harold White is planning a future experiment
33:54to see if he can warp space on a microscopic scale.
33:59He hopes to concentrate energy in a single point in space
34:03and then measure the progress of laser light crossing it.
34:07If the light completes the journey faster than normal,
34:10he'll have succeeded in warping spacetime.
34:15Everybody always asks me about, when's
34:17this going to be ready to bolt onto a spacecraft?
34:19And there's a lot of science we need to do first.
34:23We're only just now starting to look into this.
34:25We don't know if it's going to work or not.
34:26We might as well figure it out.
34:27If it does, boom.
34:29And if it doesn't, well, we've learned
34:30something interesting about math and science
34:32and the way the universe works.
34:34A warp drive would fire us to Proxima Centauri
34:37in just five months and to the 50 stars
34:42beyond in just a few years.
34:46But that's still just our galactic backyard.
34:50A warp trip to the far side of the Milky Way
34:54would take 10,000 years.
34:56And a trip beyond it to the closest galaxies,
35:00hundreds of thousands of years.
35:03Even a warp drive seems pitifully slow
35:06on the scale of the universe.
35:09But there is one last hope.
35:14Another way to go faster than the speed of light
35:17is to drill a hole in the fabric of space and time.
35:24This is called a wormhole.
35:30A wormhole is a theoretical tunnel,
35:33a rip through space-time connecting two distant points.
35:37It's created by huge concentrations
35:40of mass warping space-time.
35:43Think of Alice's looking glass.
35:45You put your hand through the looking glass
35:47and your hand winds up on the other side of the galaxy.
35:52If our spacecraft could enter this cosmic shortcut,
35:56we could jump thousands of light years in an instant.
36:00The only trouble is astronomers have never seen one.
36:04And attempting to make one would be fatal.
36:08To bend space at either mass or speed
36:11to bend space at either mouth of the wormhole to make a tunnel,
36:15you have to produce huge amounts of mass.
36:17But mass is attractive.
36:18And we can prove that if normal mass is all you have,
36:22that either end of the wormhole will
36:25collapse to form a black hole in a time scale
36:28shorter than it would take you to go through the wormhole.
36:34I don't think wormholes are ever going to work
36:36as a way of transportation.
36:38But you know what?
36:39Typically, those people who said that something couldn't
36:41happen in science turned out to be wrong.
36:44So I take that back.
36:46I think it's unlikely, but it may happen.
36:50Warp drives and wormholes are distant dreams.
36:53For now, fusion is the likely fuel to take us to the stars.
36:58But it may take millions of years for a giant space
37:01arc to colonize enough planets to guarantee our survival.
37:06The only way to go faster with fusion
37:09is to make our space arc much smaller.
37:12So small, in fact, there'd be no room for people inside.
37:17So is that really game over?
37:20Or could we save humanity without humans?
37:32Not so long ago, astronomers weren't
37:34sure if the stars they saw in the night sky
37:37had planets orbiting them.
37:39Perhaps the sun was unique and the Earth
37:42alone in the Milky Way.
37:46But over the last 20 years, we've
37:49revealed a mind-blowing truth.
37:53It seems that a large fraction of stars in the galaxy
37:56have planets.
37:57And in fact, many of those stars have multiple planets.
38:02These exoplanets range in size from gas giants
38:06bigger than Jupiter to rocky worlds like Earth.
38:10And they're everywhere we look.
38:13Our planet Earth is not unique.
38:16It's not even rare.
38:18There are tons, hordes, flocks, if you will,
38:22of other Earth-like planets out there,
38:24fluttering around the other stars.
38:27Some stars probably have multiple Earths orbiting them.
38:30That's how common Earth-like planets are.
38:35Look into the night sky and count five stars.
38:38One of those stars has an Earth-sized planet around it,
38:41maybe our next home.
38:44Apply what we've found to the rest of the Milky Way,
38:48and the results are staggering.
38:52Around sun-like stars, up to 11 billion warm, wet Earths.
38:57Around red dwarf stars, another 22 billion.
39:02And gas giant exoplanets may be home to tens of billions
39:07more potential Earths in the form of habitable exomoons.
39:12There are many Earth-like planets
39:14that we're going to have as options of places to go,
39:17almost sort of a menu spread out in front of us.
39:20Clearly, locating new Earths isn't the problem.
39:23The problem is getting there.
39:26The universe is actually kind of tantalizing us.
39:28Earth-like planets are common.
39:30They're all over the place.
39:31But they're so far away that with our current technology,
39:34we cannot imagine how to get there.
39:38A giant space ark powered by fusion engines
39:41and filled with thousands of human volunteers
39:44should allow us to colonize habitable worlds near our sun.
39:49But to go beyond that, to the far reaches of the Milky Way,
39:54we need plan B. One radical solution
40:00would be to send miniature robots instead of humans.
40:05When I think about how much we're
40:07learning about the human brain and how it works,
40:09and there's still a long way to go,
40:11it does seem to me fairly inevitable
40:12that someday we'll be able to put all of ourselves
40:15into a robot.
40:18Now, you might say, that's so sad
40:19because we want to get humans on those plans.
40:21Well, one, if you really want to think science fiction,
40:24why not ultimately take a machine that can
40:26build a human at the other end?
40:30Plants spread their genes by sowing huge numbers
40:34of tiny mobile seeds into the wind.
40:36Many seeds will be lost to the elements,
40:40but those that find warm, wet Earth come to life.
40:44Imagine firing tiny nanorobots into space, like seeds,
40:49with human genomes burned into their hard drives.
40:55If they fall through the atmosphere
40:57of a wet, warm planet suitable for humans,
41:01they spring into action.
41:03They'll land and make shelters from the materials
41:06they find on the planet, and somehow,
41:09also make the humans to live inside them.
41:13Maybe we'll send thousands of these nano-ships,
41:17as they're called, maybe millions of them, like seeds,
41:20to a nearby star, hoping that just a few of them,
41:23a few of them actually reach their destination.
41:28The technology to create a human from scratch
41:31is clearly a long way off, but it raises intriguing questions.
41:39Why should we only save humans?
41:42There are 8.7 million species on Earth.
41:45Aren't they all worth saving?
41:49And if we can't send all life on Earth,
41:52why not simply send bacteria to distant worlds
41:56and leave evolution to do the rest?
42:00And who knows?
42:01Maybe an alien species has already done that on the Earth.
42:05Maybe in your backyard, there's a nano-ship
42:08from a distant star system, and you would never know.
42:13Wherever we end up, whatever we become,
42:17the time to start planning for our survival is now.
42:23The human imagination is taking us
42:25in some truly amazing paths,
42:27and they may lead us to find a way
42:30where interstellar travel could really happen.
42:33Our fate is in many ways in our own hands.
42:36We're not dinosaurs.
42:38We have a space program.
42:40We're smart.
42:41If we have colonies on other planets,
42:44the Earth can be wiped out, and humanity won't be.
42:47In that sense, our future, our long-term future,
42:51that's in our own hands.
43:03NASA Jet Propulsion Laboratory, California Institute of Technology