Placeholder Image

字幕列表 影片播放

  • Our world, warm, comfortable, familiar...

  • ...but when we look up, we wonder:

  • Do we occupy a special place in the cosmos?

  • Or are we merely a celestial footnote?

  • Is the universe welcoming or hostile?

  • We could stand here forever, wondering.

  • Or we could leave home, on the ultimate adventure.

  • To discover wonders.

  • Confront horrors.

  • Beautiful new worlds.

  • Malevolent dark forces.

  • The beginning of time.

  • The moment of creation.

  • Would we have the courage to see it through?

  • Or would we run for home?

  • There's only one way to find out.

  • Our journey through time and space begins with a single step.

  • At the edge of space, only 6O miles up...

  • ...just an hour's drive from home.

  • Down there, life continues.

  • The traffic is awful, stocks go on trading...

  • ...and Star Trek is still showing.

  • When we return home, if we return home...

  • ...will it be the same?

  • Will we be the same?

  • We have to leave all this behind.

  • To dip our toes into the vast dark ocean.

  • On to the Moon.

  • Dozens of astronauts have come this way before us.

  • Twelve walked on the Moon itself.

  • Just a quarter of a million miles from home.

  • Three days by spacecraft.

  • Barren.

  • Desolate.

  • It's like a deserted battlefield.

  • But oddly familiar.

  • So close, we've barely left home.

  • Neil Armstrong's first footprints.

  • Looks like they were made yesterday.

  • There's no air to change them.

  • They could survive for millions of years.

  • Maybe longer than us.

  • Our time is limited.

  • We need to take our own giant leap.

  • One million miles, 5 million, 2O million miles.

  • We're far beyond where any human has ever ventured.

  • Out of the darkness, a friendly face.

  • The goddess of love, Venus.

  • The morning star.

  • The evening star.

  • She can welcome the new day in the east...

  • ...say good night in the west.

  • A sister to our planet...

  • ...she's about the same size and gravity as Earth.

  • We should be safe here.

  • But the Venus Express space probe is setting off alarms.

  • It's telling us, these dazzling clouds, they're made of deadly sulfuric acid.

  • The atmosphere is choking with carbon dioxide.

  • Never expected this. Venus is one angry goddess.

  • The air is noxious, the pressure unbearable.

  • And it's hot, approaching 900 degrees.

  • Stick around and we'd be corroded, suffocated, crushed and baked.

  • Nothing can survive here.

  • Not even this Soviet robotic probe.

  • Its heavy armor's been trashed by the extreme atmosphere.

  • So lovely from Earth, up close, this goddess is hideous.

  • She's the sister from hell.

  • Pockmarked by thousands of volcanoes.

  • All that carbon dioxide is trapping the Sun's heat.

  • Venus is burning up.

  • It's global warming gone wild.

  • Before it took hold, maybe Venus was beautiful, calm...

  • ...more like her sister planet, Earth.

  • So this could be Earth's future.

  • Where are the twinkling stars?

  • The beautiful spheres gliding through space?

  • Maybe we shouldn't be out here, maybe we should turn back.

  • But there's something about the Sun, something hypnotic, like the Medusa.

  • Too terrible to look at, too powerful to resist.

  • Luring us onwards on, like a moth to a flame.

  • Wait, there's something else, obscured by the Sun.

  • It must be Mercury.

  • Get too close to the Sun, this is what happens.

  • Temperatures swing wildly here.

  • At night, it's minus 275 degrees...

  • ...come midday, it's 800 plus.

  • Burnt then frozen.

  • The MESSENGER space probe is telling us something strange.

  • For its size, Mercury has a powerful gravitational pull.

  • It's a huge ball of iron, covered with a thin veneer of rock.

  • The core of what was once a much larger planet.

  • So where's the rest of it?

  • Maybe a stray planet slammed into Mercury...

  • ...blasting away its outer layers in a deadly game of cosmic pinball.

  • Whole worlds on the loose careening wildly across the cosmos...

  • ...destroying anything in their path.

  • And we're in the middle of it.

  • Vulnerable, exposed, small.

  • Everything is telling us to turn back.

  • But who could defy this?

  • The Sun in all its mesmerizing splendor.

  • Our light, our lives...

  • ...everything we do is controlled by the Sun.

  • Depends on it.

  • It's the Greek god Helios driving his chariot across the sky.

  • The Egyptian god Ra reborn every day.

  • The summer solstice sun rising at Stonehenge.

  • For millions of years...

  • ...this was as close as it got to staring into the face of God.

  • It's so far away...

  • ...if it burned out, we wouldn't know about it for eight minutes.

  • It's so big, you could fit one million Earths inside it.

  • But who needs numbers? We've got the real thing.

  • We see it every day, a familiar face in our sky.

  • Now, up close, it's unrecognizable.

  • A turbulent sea of incandescent gas.

  • The thermometer pushes 10,000 degrees.

  • Can't imagine how hot the core is, could be tens of millions of degrees.

  • Hot enough to transform millions of tons of matter...

  • ...into energy every second.

  • More than all the energy ever made by mankind.

  • Dwarfing the power of all the nuclear weapons on Earth.

  • Back home, we use this energy for light and heat.

  • But up close, there's nothing comforting about the Sun.

  • Its electrical and magnetic forces erupt in giant molten gas loops.

  • Some are larger than a dozen Earths.

  • More powerful than 10 million volcanoes.

  • And when they burst through, they expose cooler layers below...

  • ...making sunspots.

  • A fraction cooler than their surroundings, sunspots look black...

  • ...but they're hotter than anything on Earth.

  • And massive, up to 2O times the size of Earth.

  • But one day, all this will stop.

  • The Sun's fuel will be spent.

  • And when it dies, the Earth will follow.

  • This god creates life, destroys it...

  • ...and demands we keep our distance.

  • This comet strayed too close.

  • The Sun's heat is boiling it away...

  • ...creating a tail that stretches for millions of miles.

  • It's freezing in here.

  • There's no doubt where this comet's from, the icy wastes of deep space.

  • But all this steam and geysers and dust...

  • ...it's the Sun again, melting the comet's frozen heart.

  • Strange.

  • A kind of vast, dirty snowball, covered in grimy tar.

  • Tiny grains of what looks like organic material...

  • ...preserved on ice, since who knows when...

  • ...maybe even the beginning of the solar system.

  • Say a comet like this crashed into the young Earth billions of years ago.

  • Maybe it delivered organic material and water...

  • ...the raw ingredients of life.

  • It may even have sown the seeds of life on Earth...

  • ...that evolved into you and me.

  • But say it crashed into the Earth now.

  • Think of the dinosaurs, wiped out by a comet or asteroid strike.

  • It's only a question of time.

  • Eventually, one day, we'll go the way of the dinosaurs.

  • If life on Earth was wiped out, we'd be stuck out here...

  • ...homeless, adrift in a hostile universe.

  • We'd need to find another home.

  • Among the millions, billions of planets...

  • ...there must be one that's not too hot, not too cold, with air, sunlight, water...

  • ...where, like Goldilocks, we could comfortably live.

  • The red planet.

  • Unmistakably Mars.

  • For centuries, we've looked to Mars for company...

  • ...for signs of life.

  • Could there be extraterrestrial life here?

  • Are we ready to rewrite the history books, to tear up the science books...

  • ...to turn our world upside down?

  • What happens next could change everything.

  • Mars is the planet that most captures our imagination.

  • Think of B-movies, sci-fi comics, what follows?

  • Martians?

  • It's all just fiction, right?

  • But what if there really is something here?

  • Hard to imagine, though. Up close, this is a dead planet.

  • The activity that makes the Earth livable shut down millions of years ago here.

  • Red and dead.

  • Mars is a giant fossil.

  • Wait. Something is alive.

  • A dust devil, a big one.

  • Bigger than the biggest twisters back home.

  • There's wind here.

  • And where there's wind, there's air.

  • Could that air sustain extraterrestrial life?

  • It's too thin for us to breathe.

  • And there's no ozone layer.

  • Nothing to protect us against the Sun's ultraviolet rays.

  • There is water...

  • ...but frigid temperatures keep it in a constant deep freeze.

  • It's hard to believe anything could live here.

  • Back on Earth, there are creatures that survive in extreme cold, heat...

  • ...even in the deepest ocean trenches.

  • It's as though life is a virus.

  • It adapts, spreads.

  • Maybe that's what we're doing right now...

  • ...carrying the virus of life across the universe.

  • Even in the most extreme conditions, life usually finds a way.

  • But on a dead planet?

  • With no way to replenish its soil, no heat to melt its frozen water?

  • All this dust, it's hard to see where we're going.

  • Olympus Mons, named after the home of the Greek gods.

  • A vast ancient volcano.

  • Three times higher than Everest.

  • There's no sign of activity.

  • Since its discovery in the 1970s, it's been declared extinct.

  • Hang on.

  • These look like lava flows.

  • But any sign of lava should be long gone, obliterated by meteorite craters.

  • Unless, this monster isn't dead, just sleeping.

  • There could be magma flowing beneath the crust right now...

  • ...building up, waiting to be unleashed.

  • Volcanic activity could be melting frozen water in the soil...

  • ...pumping gases into the atmosphere, recycling minerals and nutrients.

  • Creating all the conditions needed for life.

  • This makes the Grand Canyon look like a crack in the sidewalk.

  • Endless desolation...

  • ...so vast it would stretch all the way across North America.

  • But here, signs of activity, erosion, and what looks like dried up river beds.

  • Maybe volcanic activity melted ice in the soil...

  • ...sending water gushing through this canyon.

  • Underground volcanoes could still be melting ice, creating water.

  • And where there's water, there could be life.

  • The hunt for life is spearheaded by this humble fellow...

  • ...the NASA rover, Opportunity.

  • It's finding evidence that these barren plains...

  • ...were once ancient lakes or oceans that could have harbored life.

  • Look at those gullies.

  • Probes orbiting Mars keep spotting new ones.

  • More proof that Mars is alive and kicking...

  • ...that water is flowing beneath its surface right now.

  • Water that could be sustaining Martian life.

  • Now, all we have to do is find it.

  • Maybe we've already found what we're looking for on Earth.

  • Some think that life started here and then migrated to Earth.

  • An asteroid impact could've blasted fragments of Mars...

  • ...complete with tiny microbes out into space...

  • ...and onto the young Earth where they sowed the seeds of life.

  • No wonder we find Mars fascinating, this could be our ancestral home.

  • It could be we are all Martians.

  • The Mars we thought we knew is gone...

  • ...replaced by this new, active, changing planet.

  • And if we don't know Mars, our next door neighbor...

  • ...how can we even imagine what surprises lie ahead?

  • Our compass points across the cosmos...

  • ...back in time 14 billion years...

  • ...to the moment of creation.

  • This is getting scary.

  • It's like being inside a giant video game.

  • But these are all too real.

  • Asteroids, some of them hundreds of miles wide.

  • This one must be about 2O miles long.

  • And there, perched on it, a space probe.

  • Can't have been easy...

  • ...parking on an asteroid traveling at 50,000 miles an hour.

  • It's a lot of effort just to investigate some rubble.

  • Rubble that regularly collides...

  • ...breaks up and rains down on Earth as meteorites.

  • Our ancestors saw shooting stars as magical omens.

  • And they were right.

  • Rubble like this came together to make the planets...

  • ...including our own.

  • Pretty magical.

  • By dating the meteorites found on Earth...

  • ...we can tell the planets were born 4.6 billion years ago.

  • These are the birth certificates of our solar system.

  • For some reason, these rocks didn't form into a planet.

  • Something must have stopped them.

  • Something powerful.

  • Jupiter.

  • What a monster.

  • At least a thousand times bigger than Earth...

  • ...so vast you could fit all the other planets inside it.

  • Something this massive dominates its neighbors.

  • Its gravity is pulling the asteroids apart.

  • And it's breathtaking.

  • But this beauty is a beast.

  • It's almost all gas.

  • Land here and we'd sink straight through its layers into oblivion.

  • And Jupiter's good looks?

  • The product of ferocious violence.

  • It's spinning at an incredible rate...

  • ...whipping up winds to hundreds of miles an hour...

  • ...contorting the clouds into stripes, eddies, Whirlpools...

  • ...and this, the legendary Great Red Spot.

  • The biggest, most violent storm in the solar system.

  • At least three times the size of Earth, it's been raging for over 300 years.

  • All these churning clouds must have sparked an electrical storm.

  • Just one bolt is 10,000 times more intense than any at home.

  • Looks like the safest place to see Jupiter is from a distance.

  • Up there at the poles...

  • ...those dancing lights, they're like the auroras back home.

  • But the Geiger counter is going wild.

  • Even these are deadly, generated by lethal radiation.

  • Out here, nothing is what it seems.

  • The universe is full of terrors, traps.

  • Maybe this is a safe haven, the multi-colored moon, lo.

  • Wrong.

  • Very wrong.

  • Those brilliant colors are molten rock, volcanoes spewing lava.

  • Our journey across the universe is turning into a struggle for survival.

  • We've got to hope that if we outlast the dangers...

  • ...we'll be rewarded by wonders beyond imagination.

  • Four hundred million miles from Earth...

  • ...flying a commercial airliner here would take nearly a century.

  • What a weird looking place...

  • ...and yet, strangely familiar.

  • A bit like the Arctic, with all that ice, all those ridges and cracks.

  • It's Jupiter's moon, Europa.

  • And maybe, like the Arctic, this ice is floating on water, liquid water.

  • But we're half a billion miles from the Sun.

  • Surely, Europa is frozen solid.

  • Unless, Jupiter's gravity is creating friction deep inside...

  • ...heating the ice into water, allowing life to develop in the waters...

  • ...beneath its frozen crust.

  • We might be feet away from aliens.

  • From a whole ecosystem of microbes, crustaceans, maybe even squid.

  • The only thing between us and the possibility of alien life...

  • ...this layer of ice.

  • But until we send a spacecraft to drill here...

  • ...Europa's secrets will remain beyond reach.

  • It's captivated our imaginations, haunted our dreams.

  • And here it is, spinning before our eyes.

  • Saturn.

  • Named for the Roman god...

  • ...who reigned over a golden age of peace and harmony.

  • This planet's a giant ball of gas, so light it would float on water.

  • Its spectacular rings would stretch almost from Earth to the Moon.

  • There's the Cassini orbiter.

  • It's picking up ghostly radio emissions.

  • Probably generated by auroras around Saturn's poles.

  • This is the real music of the spheres.

  • [HISSING PLAYING OVER RADIO]

  • Cassini's telling us where these rings came from.

  • They're the remnants of a moon shattered by Saturn's gravitational pull.

  • Incomparable beauty from total destruction.

  • Billions of shards of ice.

  • Some as small as ice cubes, others the size of houses.

  • They collide, break apart, reassemble.

  • It's like a snapshot of our early solar system...

  • ...as dust and gas orbited the newly born Sun...

  • ...and gravity worked its magic, pulling the lumps together...

  • ...until from space trash like this, our home emerged.

  • We could stay here forever.

  • But there's so much further to go, so much more to see.

  • Like this moon wrapped in thick clouds, Titan.

  • There's an atmosphere down here.

  • There's wind, rain, even seasons.

  • Rivers, lakes and oceans.

  • It looks so familiar, so similar to Earth.

  • [THUNDER RUMBLING]

  • But that's not water, it's liquid natural gas.

  • Hundreds of times more natural gas than all the Earth's oil and gas reserves.

  • Maybe, one day, we'll use this energy to fuel a colony.

  • Assuming there isn't life here already.

  • The Huygens space probe is here to find out.

  • It's telling us there's organic material in the soil.

  • But it's so cold, minus 300 degrees.

  • There's no way life could develop.

  • Unless Titan warms up.

  • The Sun is supposed to get hotter.

  • When it does, maybe life will spring up here...

  • ...just like it did on Earth.

  • And as the Earth gets too hot for us, maybe we'll move to Titan.

  • One day, we might call this distant land home.

  • Home.

  • We're at least 700 million miles away now.

  • After this, we lose visual contact with Earth.

  • We're standing on a cliff.

  • Looking out over a great chasm that stretches to the beginning of time.

  • Do we have the courage to jump?

  • We're in the solar system's outer reaches.

  • Unseen from Earth, unknown for most of history.

  • It's like diving into the depths of the ocean.

  • Those rings make it look like Uranus has been tilted off its axis...

  • ...toppled over by a stray planet.

  • It's eerie out here.

  • Already beginning to feel small, lonely.

  • Maybe this is how we'll feel at the edge of the universe.

  • But we've barely left the shore.

  • If the solar system was one mile wide, so far we've traveled about 3 inches.

  • Out of the deep, another strange beast...

  • ...the god of the sea, Neptune.

  • This world is covered in methane gas.

  • And a storm as big as Earth...

  • ...whipped up by savage thousand mile-an-hour winds.

  • Back home, it's the Sun that drives the wind...

  • ...but Neptune's far away.

  • Something else must be creating these ferocious winds.

  • But what?

  • We know very little about our own solar system.

  • After all those balls of gas, a solid moon...

  • ...Triton.

  • Solid but not stable.

  • Just look at those geysers...

  • ...cosmic smokestacks pumping out strange soot.

  • And this moon is revolving around Neptune...

  • ...in the opposite direction of the planet's spin.

  • A cosmic battle of wills...

  • ...that this angry moon is destined to lose.

  • Neptune's massive gravity is pulling on Triton.

  • Slowing it down, reeling it in.

  • One day, it will be ripped apart by Neptune.

  • And that's it.

  • No more moons, no more planets in our solar system.

  • It's getting colder, we're getting further from the Sun...

  • ...slipping from the grip of its gravitational tentacles.

  • But this isn't a void.

  • It's teeming with frozen rocks.

  • Like Pluto.

  • Until recently, we thought Pluto was alone.

  • Beyond it, nothing.

  • We were wrong.

  • More frozen worlds.

  • Discoveries so new nobody can agree what to call them.

  • Plutinos, ice dwarves, cubewanos.

  • Our solar system is far more chaotic and strange than we had imagined.

  • Now we're 8 billion miles from home.

  • The most distant thing ever seen that orbits the Sun...

  • ...another small, icy world, Sedna, discovered in 2003.

  • Its orbit takes 10,000 years to complete.

  • Hang on, there's something else out here.

  • Ten billion miles from home the space probe, Voyager 1.

  • This bundle of aluminum and antennae...

  • ...gave us close up views of the giant planets...

  • ...and discovered many of their strange moons.

  • It's traveling 20 times faster than a bullet, sending messages home.

  • That gold plaque...

  • ...its a kind of intergalactic message in a bottle.

  • A greeting recorded in different languages.

  • BOY [OVER RADIO]: Hello, from the children of planet Earth.

  • [MAN AND WOMAN SPEAKING IN FOREIGN LANGUAGES OVER RADIO]

  • NARRATOR: And a map showing how to find our home solar system.

  • The great physicist, Stephen Hawking...

  • ...thinks it was a mistake to roll out the welcome mat.

  • After all, if you're in the jungle, is it wise to call out?

  • These comets look like the ones we saw earlier.

  • There's a theory that the raw materials for life began out here...

  • ...on a rock like this until something dislodged it...

  • ...sending it hurtling towards the Earth.

  • And seeing all this ice, maybe comets carried water to Earth too.

  • The water in the oceans, in your body...

  • ...all from this distant celestial ice machine.

  • We're 5 million, million, that's 5 trillion miles from home.

  • But this is still only a baby step.

  • Ahead, trillions of miles, billions of stars.

  • Time to stop looking back and start looking ahead...

  • ...to step out into the big, wide universe.

  • Interstellar space.

  • Billions of stars like our own Sun...

  • ...many with planets, many of those with moons.

  • It's hard to know which way to go.

  • There are infinite possibilities.

  • We're going to need a serious burst of acceleration.

  • Twenty-five trillion miles from home.

  • A 150,000-year ride in the space shuttle.

  • And we've only just reached the first solar system beyond our own...

  • ...Alpha Centauri.

  • Not one but three stars.

  • Spinning around each other, locked in a celestial standoff.

  • Each star's gravity attracting the other...

  • ...their blazing orbital speed keeping them apart.

  • Get between them and we'd be vaporized...

  • ...trillions of miles from home.

  • So far that miles are becoming meaningless.

  • Out here, we measure in light years.

  • Light travels 6 trillion miles a year...

  • ...so we are over four light-years from home.

  • Distances so vast they're mind-boggling.

  • Who knows what strange forces lie ahead...

  • ...what we'll discover when--

  • If we reach the edge of the universe.

  • Ten light years from Earth, the star Epsilon Eridani.

  • Spectacular rings of dust and ice.

  • And somewhere in there, planets forming out of the debris...

  • ...being born before our eyes.

  • Asteroids and comets everywhere.

  • We could almost be looking at our own solar system...

  • ...billions of years ago.

  • With comets delivering the building blocks of life...

  • ...to these young planets.

  • At the center of all the action, a star smaller than our sun...

  • ...still in its infancy.

  • Any life in this solar system would be primitive at best.

  • There must be more mature solar systems out here...

  • ...but finding them is like looking for a needle in a cosmic haystack.

  • Twenty light years from Earth.

  • Star Gliese 581.

  • It's about the same age as our sun.

  • This planet is just the right distance from its sun.

  • Any closer and water would boil away, any further and it would freeze.

  • Ideal conditions for life to emerge.

  • And if a comet has struck, delivering water and organic materials...

  • ...then life, complex beings like us, even civilizations like our own...

  • ...could be down there right now.

  • They could be tuning into our TV signals...

  • ...watching shows from 2O years ago.

  • MAN [OVER TV]: And here's your host, Joe...

  • [PEOPLE APPLAUDING ON TV]

  • NARRATOR: But until we devise a way of communicating...

  • ...over these vast distances, all we can do is speculate.

  • Us and them, living parallel lives...

  • ...unaware of each other's existence.

  • Unless life has come and gone.

  • That's the problem with comets.

  • They're creators and destroyers...

  • ...as the dinosaurs found out the hard way.

  • This is the needle in the cosmic haystack...

  • ...the closest we've come to a habitable solar system like our own...

  • ...but it's a chance encounter.

  • There could be hundreds...

  • ...millions more solar systems like this out there or none at all.

  • Some of the atmosphere on this planet, Bellerophon...

  • ...is being boiled away by its nearby star.

  • From Earth, we can't see planets this far out.

  • They're obscured by the brilliance of their neighboring stars.

  • But the planets have a minute gravitational pull on those stars.

  • Measure these tiny movements and we can prove they exist.

  • That's how we tracked down Bellerophon in the 1990's...

  • ...and hundreds of other distant planets.

  • Sixty-five light years from Earth...

  • ...turn on your TV here and you'd pick up Hitler's Berlin Olympics.

  • [MAN SPEAKING IN GERMAN ON TV]

  • The twin stars of Algol.

  • Known to the ancients as the demon star.

  • From Earth, it appears to blink as one star passes across the other.

  • Up close, it's even stranger.

  • One star is being sucked towards the other.

  • Almost 100 light years from home...

  • ...faint whispers from one of the first ever radio broadcasts.

  • [STATIC HISSES OVER RADIO]

  • MAN [OVER RADIO]: We'd appreciate it...

  • ...if anyone hearing this broadcast would communicate with us.

  • We are very anxious to know how far the broadcast can reach.

  • NARRATOR: From here on out, it's as if the Earth never existed.

  • Feels like a lifetime since we stood on that beach...

  • ...looking up at the sky, wondering where and how we fit in.

  • We've learned one thing for sure.

  • The universe is too bizarre, too startling...

  • ...for us to guess what lies ahead.

  • Deep inside our galaxy, the Milky Way.

  • Pinpricks of light that have inspired a thousand and one tales.

  • The Seven Sisters, the daughters of the ancient Greek god, Atlas...

  • ...transformed into stars to comfort their father...

  • ...as he held the heavens on his shoulders.

  • And this giant, Betelgeuse.

  • The brightest, biggest star we've seen so far.

  • Six hundred times wider than our sun.

  • But this, it's not a star...

  • ...not a planet, not like anything we've seen.

  • A ghostly specter, more than 1,300 light years from Earth...

  • ...Orion's dark cloud.

  • Dust and gas shrouding us.

  • There, deep inside, a light, pulling the dust and gas towards it...

  • ...heating up, merging into a ball of burning hot gas.

  • Like a star, like our sun in miniature.

  • Inside, it's millions of degrees.

  • So hot, it's beginning to trigger nuclear reactions...

  • ...the kind that keep our sun shining...

  • ...making energy, radiation, light.

  • A star is being born.

  • Orion's dark cloud is a vast star factory.

  • We're witnessing the birth of the future universe.

  • We've come to expect destruction...

  • ...but this is one of the universe's greatest acts of creation.

  • Star birth.

  • This doesn't look right.

  • Jets of gas exploding out with tremendous force...

  • ...blasting dust and gas out for millions of miles.

  • It's unbelievably violent and creative.

  • Nebula...

  • ...vast glowing clouds of gas hanging in space.

  • With no wind out here, they'll take thousands of years to disperse.

  • They seem to be forming a vast stellar sculpture.

  • Nature is more than a scientist, an engineer...

  • ...it's an artist on the grandest of scales.

  • And this is a masterpiece.

  • Stars are born, grow up, and then, then what?

  • Do they die?

  • Do they slip quietly into the night or go out with a bang?

  • Somewhere between here and the edge of the universe lies the answer.

  • Luminous clouds, suspended in space...

  • ...encircling what was once a star like our own sun.

  • All that's left of it are these brightly colored gases...

  • ...elements formed by nuclear reactions deep inside...

  • ...released into space on its death.

  • Green and violet, hydrogen and helium...

  • ...the raw materials of the universe.

  • Red and blue, nitrogen and oxygen...

  • ...the building blocks of life on Earth.

  • For us to live, stars like this had to die.

  • Every atom in our body was produced by nuclear fusion...

  • ...in stars that died long before the Earth was even born.

  • We are all the stuff of stars.

  • Our family tree begins here.

  • At its heart, the ghost of a star...

  • ...a white dwarf.

  • White, hot, small...

  • ...but unbelievably dense.

  • In the star's dying moments, its atoms fused and squeezed together...

  • ...making it so dense that just a teaspoon of this white dwarf would weigh 1 ton.

  • It's a chilling premonition of our sun's fate.

  • Six billion years from now, it will become a white dwarf.

  • Its death will herald the end of life on Earth.

  • Makes you wonder how many other worlds have come and gone...

  • ...celestial stories left untold, lost forever.

  • But the greatest story of them all is still to be told.

  • We must go back through time to the very first chapter...

  • ...to learn how the universe began.

  • The scattered remains of a dead star...

  • ...the Crab Nebula.

  • Six thousand light years from home, deep inside a stellar graveyard.

  • We've learnt so much...

  • ...seen things we'd never have believed possible.

  • Now, sights like this, wonders once beyond imagination...

  • ...we take in our stride.

  • We're ready to face whatever lies ahead.

  • Determined to reach the edge of the universe.

  • This is the calm after the storm, after a massive explosion...

  • ...a supernova that turned a star into dust and gas.

  • The eye of the storm.

  • A spinning pulsating star, a pulsar.

  • The gravity has squeezed the giant star's core down to this.

  • It's just 12 miles across, unimaginably dense.

  • One pinhead of this would weigh hundreds...

  • ...maybe millions of tons.

  • And as it shrank, like a figure skater spinning on the spot...

  • ...arms outstretched, then pulling them in...

  • ...it began to spin faster.

  • Two beams of light, energy, radiation, spinning 30 times a second.

  • Powering the huge cloud of dust and gas.

  • There's so much radiation here, more even than on the Sun.

  • That was easily the deadliest thing we've encountered so far.

  • Once, it would have terrified us.

  • But now we realize that without the dangers...

  • ...there'd be no wonders.

  • Without the nightmares, there'd be no dreams.

  • Getting a strange sensation.

  • A feeling as though there's something bad out here...

  • ...a malevolent presence.

  • The one thing we didn't want to encounter.

  • Impossibly black, blotting out the stars behind it.

  • We're staring into the face of extinction...

  • ...the remains of a giant star...

  • ...a black hole.

  • Far denser than a pulsar...

  • ...and impossible to resist.

  • Its gravity is so intense, not even light can escape.

  • This asteroid, it's a lump of solid rock...

  • ...but it's actually stretching, being dragged towards the gaping hole.

  • Inside, there's no matter as we know it.

  • No time, no space, all the rules of physics collapse.

  • The asteroid is gone.

  • Nobody really knows where.

  • This is the edge of human understanding.

  • There could be millions of black holes creeping around our galaxy...

  • ...more perhaps than all the stars in the sky...

  • ...but we wouldn't see them until it was too late.

  • Like this star, spiraling...

  • ...disappearing, down an invisible sinkhole.

  • Who's to say we don't live inside a vast black hole...

  • ...that the whole universe isn't inside one right now...

  • ...inside another universe?

  • Think about it for too long and your mind reels.

  • Sometimes it feels like the more we see, the less we know.

  • And we're still in our own galaxy, the Milky Way...

  • ...the vastness of the universe beyond still lies ahead.

  • The wonders, the dangers, the secrets, they're out there...

  • ...waiting to be discovered.

  • Seven thousand light years from home.

  • It's as though we're in a forest thick with trees.

  • Each so beautiful, so fascinating, it's impossible to look beyond...

  • ...to see the bigger picture.

  • We have to find a way through...

  • ...to reach the clearing at the galaxy's edge.

  • But faced with sights like this, it's hard to leave.

  • A colossal glowing cloud topped by these great towers of dust...

  • ...the Pillars of Creation.

  • Like a gateway into the unknown.

  • A star factory packed with embryonic star systems...

  • ...each larger than our solar system.

  • We have to resist its siren song, tear ourselves away...

  • ...to carry on towards the edge of the galaxy.

  • Dazzled by the Milky Way's beauty, we've been blinded to its terrors...

  • ...and strayed into a cosmic minefield.

  • Like an explosion in slow motion.

  • A massive star, millions of times brighter than our sun.

  • It's going into meltdown.

  • The fuel that sustains it is running out...

  • ...the nuclear reactions that power it winding down.

  • We're watching its death throes.

  • An even bigger, dangerously unstable star.

  • But this one's about to explode.

  • And when a star this big dies...

  • ...it's a hundred times more violent than a supernova.

  • We've stumbled into the most violent star death of all...

  • ...a hypernova.

  • The core's collapsed, it's becoming a black hole.

  • And that's the shock wave, surging through the star...

  • ...ripping its outer layers into space.

  • Deadly hypernovas, frozen comets...

  • ...scorched planets, white dwarves, red giants.

  • Tiny drops in a vast pool of white light...

  • ...our home galaxy, the Milky Way.

  • We wanted to know where we fit in.

  • Here's our answer.

  • Civilizations, past and present.

  • Everyone that's ever lived.

  • The smallest bug, the highest mountain...

  • ...all of it invisible, not even a tiny speck.

  • Our home is a minor planet orbiting an insignificant star.

  • If it disappeared right now, who would even notice?

  • And yet, so far, we've found nowhere else we would rather live...

  • ...nowhere we could live.

  • It's only now, far from home...

  • ...that we're beginning to truly appreciate it.

  • Look at all these stars, hundreds of thousands of them.

  • Surely one of them, more than one, must be capable of supporting life.

  • Maybe here in this swarm of stars, the Great Cluster.

  • Back in the 1970's, astronomers sent a message in this direction...

  • ...detailing the structure of our DNA and our solar system's location.

  • But the message won't arrive here for another 25,000 years.

  • We haven't found alien life yet.

  • But neither have we found any reason to believe...

  • ...it isn't out there somewhere.

  • There's an equation devised...

  • ...to estimate the number of other advanced civilizations.

  • The result is startling.

  • There could be millions of civilizations just in our own galaxy.

  • Everything we've seen so far is inside the Milky Way.

  • Now we're ready to leave our home galaxy...

  • ...to enter intergalactic space.

  • Here's our chance to solve the ultimate mystery...

  • ...and experience the moment of creation.

  • Beyond the Milky Way...

  • ...through the vast expanse between galaxies.

  • Against all the odds, we've made it to intergalactic space.

  • Out here, there's no horizon in sight.

  • Even the closest galaxies are hundreds of thousands of light years away.

  • The remains of galaxies ripped apart...

  • ...by the Milky Way's huge gravitational pull...

  • ...scattered among nothing.

  • This is as close as the universe gets to a perfect vacuum.

  • But even this isn't totally empty.

  • There are thin wisps of gas, fine traces of dust.

  • And something else, dark matter.

  • So mysterious, we can't see it...

  • ...feel it, taste it, touch it or even measure it.

  • Yet so common, it could make up over 9O percent...

  • ...of all the matter in the universe.

  • If dark matter does exist...

  • ...it means there's no such thing as empty space.

  • Even out here, we're surrounded by matter.

  • We think it exists because of its apparent hold on galaxies.

  • Like this one, the Large Magellanic Cloud.

  • A 6-billion-year journey in today's fastest spacecraft...

  • ...160 thousand light years from the Milky Way...

  • ...at the edge of its gravitational reach.

  • This galaxy should spin off into space, but something is holding it here...

  • ...something invisible, powerful, dark matter.

  • Stars, clusters of stars, nebulae...

  • ...it's a vast astronomical treasure trove.

  • But look at this, it's like a string of gleaming pearls.

  • It's a fireball...

  • ...expanding out from what must have been a massive explosion.

  • A supernova.

  • So bright that when light from the explosion reached Earth 20 years ago...

  • ...it was visible to the naked eye.

  • And so violent, it triggered a string of nuclear reactions...

  • ...forcing atoms together, creating new elements...

  • ...gold, silver, platinum, blasting them out into space.

  • The gold in the ring on your finger...

  • ...was forged in a massive supernova like this...

  • ...trillions of miles away, billions of years ago.

  • Before we left home, the universe seemed separate...

  • ...something out there, up in the sky.

  • But now we know better.

  • We are the universe, and it is within us.

  • It's comforting to remember as we venture through this abyss.

  • Further and further.

  • Faster and faster.

  • The Andromeda Galaxy two and a half million light years away.

  • It's racing through space...

  • ...everything blown apart, like shrapnel in an explosion.

  • We're seeing this galaxy as it was...

  • ...when our ape-like ancestors first walked on the African plains.

  • Further through space, and further back in time...

  • Hold on. This doesn't look right.

  • A whole galaxy exploding?

  • The only thing large enough to cause an explosion on this scale...

  • ...is another galaxy.

  • It looks like the end of the world.

  • But this galaxy won't die, it will be reborn.

  • A new shape, perhaps even new stars...

  • ...as dust and gas collide, creating friction, shockwaves...

  • ...triggering the birth of stars.

  • There's order in this chaos, a pattern behind the infinite variety...

  • ...an endless cycle of birth and death, creation and destruction.

  • It's a pattern woven through the vast fabric of space...

  • ...that binds each of these galaxies.

  • There are billions of galaxies...

  • ...each with billions, even trillions of stars.

  • Maybe more stars than there are grains of sand...

  • ...on all the beaches on Earth.

  • We're finally beginning to see the big picture...

  • ...and it's grander than we ever imagined.

  • This galaxy, the huge Pinwheel Galaxy...

  • ...is so far from Earth that if we send a message home now...

  • ...it will take 27 million years to get there.

  • Who knows whether our species, our planet...

  • ...will still be around to receive it?

  • We travel on, back through time.

  • Past the point where the dinosaurs were wiped out...

  • ...past the moment where the first creatures crawled onto land.

  • Two billion light years from home.

  • Closing in on the edge of the universe.

  • Going back to the beginning of time.

  • This isn't a galaxy. It's brighter than a hundred galaxies.

  • A blinding beam of energy surging for trillions of miles.

  • Something this big, this bright, must be incredibly powerful.

  • Experience tells us, out here, power equals danger.

  • It looks like a quasar, the deadliest thing in the universe.

  • Our journey could be over.

  • The deadliest, most powerful thing in the universe.

  • A quasar.

  • A swirling cauldron of superheated gas.

  • This beast has a heart of darkness, a super-massive black hole...

  • ...as heavy as a billion suns.

  • It's ripping apart whole stars...

  • ...devouring them until they're nothing...

  • ...lost forever from the visible universe.

  • We think, we hope, we pray...

  • ...we've seen the worst the universe can throw at us.

  • But no one can know what lies ahead.

  • We'll need to go further, go faster.

  • Eight billion light years from home.

  • More galaxies, but these look different.

  • Ragged, small, close together.

  • We're so far back in time...

  • ...we're seeing these galaxies as they were before the Earth was born.

  • They're still young, still growing.

  • We're getting close to where and how it all began.

  • Look at the galaxies now.

  • They're more like primitive plankton floating in a vast dark ocean.

  • Clouds of dust and gas...

  • ...dancing, twirling, merging to make embryonic galaxies.

  • They're disappearing.

  • We've gone back before the stars were born...

  • ...into a cosmic dark age.

  • And before that, light, the afterglow...

  • ...from the massive explosion that created the known universe.

  • This is it.

  • We've made it.

  • The edge of the universe...

  • ...8O billion trillion miles from home...

  • ...13 and a half billion years ago.

  • The very instant of the Big Bang...

  • ...the most violent, most creative moment in history.

  • Everything that's ever happened follows from this moment.

  • Every religion, every culture, has pondered it.

  • But we still don't know what sparked this act of creation or why.

  • This is where our journey ends...

  • ...and the universe begins.

  • An infinitely hot, small, dense point erupts.

  • Creating space, time, matter, our universe itself.

  • First, it's the size of a subatomic particle.

  • The tiniest fraction of a second later...

  • ...it's big enough to hold in the palm of your hand.

  • Moments later, it's the size of the Earth.

  • Today, the light from the Big Bang is still spreading out.

  • You can hear it as a radio hiss.

  • See it as television static.

  • All the wonders we've seen on our journey...

  • ...are sparks flying out from the Big Bang.

  • Galaxies, stars, planets...

  • ...all cosmic debris.

  • We go forward through time...

  • ...riding the blast wave.

  • Until we reach another cooling cinder...

  • ...swirling in the afterglow of the Big Bang.

  • We're back where we started.

  • Home.

  • Only now can we really know it.

  • Smaller, more fragile than we ever imagined.

  • Destined to die, swallowed by a dying sun.

  • But we shouldn't despair. We should rejoice.

  • We've managed to experience the wonders of the universe.

  • We should celebrate our achievements...

  • ...and enjoy our moment in the sun.

Our world, warm, comfortable, familiar...

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B2 中高級

宇宙邊緣之旅 (高清) + 英文字幕 (Journey to the Edge of the Universe (HD) + english subtitles)

  • 455 31
    稲葉白兎 發佈於 2021 年 01 月 14 日
影片單字