《旅行到宇宙边缘》英文解说

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 footnoteIs the universe welcoming or hostile?We could stand here forever, wonderingOr we could leave home on the ultimate adventureTo discover wondersConfront horrorsBeautiful new worldsMalevolent dark forcesThe 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 outOur journey through time and space begins with a single step. At the edge of space, only 60 miles up......just an hour's drive from homeDown there, life continues.The traffic is awful, stocks go on trading...and Star Trek is still showingWhen we return home, if we return home......will it be the same?Will we be the same?We have to leave all this behindTo dip out toes into the vast dark oceanOn to the Moon.Dozens of astronauts have come this way before usTwelve walked on the moon itselfJust a quarter of a million miles from home.Three days by spacecraftBarren.Desolate.It's like a deserted battlefieldBut oddly familiar.So close, we've barely left homeNeil Armstrong's first footprints.Looks like they were made yesterdayThere's no air to change them.They could survive for millions of yearsMaybe longer than us.Our time is limitedWe need to take our own giant leapOne million miles, 5 million, 20 million miles.We're far beyond where any human has ever venturedOut of the darkness, a friendly faceThe goddess of love, Venus.The morning star.The evening star.She can welcome the new day in the east......say good night in the westA sister to our planet......she's about the same size and gravity as Earth.We should be safe hereBut the Venus Express space probe is setting off alarmsIt's telling us, these dazzling clouds, they're made of deadly sulfuric acid The atmosphere is choking with carbon dioxideNever expected this Venus is one angry goddess.The air is noxious, the pressure unbearable.And it's hot, approaching 900 degreesStick 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 hideousShe's the sister from hell.Pockmarked by thousands of volcanoesAll that carbon dioxide is trapping the Sun's heat.Venus is burning up.It's global warming gone wildBefore it took hold, maybe Venus was beautiful, calm......more like her sister planet, Earth.So this could be Earth's futureWhere are the twinkling stars?The beautiful spheres gliding through space?Maybe we shouldn't be out here, maybe we should turn backBut there's something about the Sun, something hypnotic, like the Medusa Too terrible to look at, too powerful to resistLuring us onward on, like a moth to a flame.Wait ,there's something else, obscured by the sunIt must be Mercury.Get too close to the sun, this is what happens.Temperatures swing wildly hereAt night, it's minus 275 degreese 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 rockThe 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 pathAnd we're in the middle of itVulnerable, exposed, smallEverything is telling us to turn back.But who could defy this?The Sun in all its mesmerizing splendorOur light, our lives......everything we do is controlled by the SunDepends on itIt's the Greek god Helios driving his chariot across the skyThe Egyptian god Ra reborn every dayThe summer solstice sun rising at Stonehenge.For millions of years......this was as close as it got to staring into the face of GodIt's so far away......it is burned out, we wouldn't know about it for eight minutesIt's so Big, you could fit one million Earths inside itBut who needs number? we've got the real thingWe see it every day, a familiar face in our skyNow, up close, it's unrecognizable.A turbulent sea of incandescent gasThe thermometer pushes 10,000 degreescan'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 secondMore than all the energy ever made by mankindDwarfing the power of all the nuclear weapons on Earth.Back home, we use this energy for light and heatBut 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 EarthsMore powerful than 10 million volcanoes.And when they burst through they expose cooler layers below... ...making sunspots.A fraction cooler than their surrounding, sunspots look black......But they're hotter than anything on Earth.And massive up to 20 times the size of Earth.But one day, all this will stopThe Sun's fuel will be spent.And when it dies, the Earth will followThis god creates life, destroys it......and demands we keep out distanceThis comet strayed too closeThe 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 spaceBut 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 tarTiny 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 lifeIt may even have sown the seeds of life on Earth......that evolved into you and meBut say it crashed into the Earth nowThink of the dinosaurs, wiped out by a comet or asteroid strikeIt's only a question of time.Eventually, one day, we'll go the way of the dinosaursIf life on Earth was wiped out, we'd be stuck out here......homeless, adrift in a hostile universeWe'd need to find another homeAmong 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 liveThe red planetUnmistakably Mars.For centuries, we've looked to Mars for company......for signs of lifeCould 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 everythingMars 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 it there really is something here?Hard to imagine, though. Up close, this is a dead planetThe activity that makes the Earth livable shut down millions of years ago here Red and deadMars is a giant fossil.Wait. Something is aliveA dust devil, a big oneBigger than the biggest twisters back home.There's wind hereAnd where there's wind, there's airCould that air sustain extraterrestrial life?It's too thin tor us to breathe.And there's no ozone layerNothing to protect us against the Sun's ultraviolet rays.There is water......But frigid temperatures keep it in a constant deep freezeIt's hard to believe anything could live hereBack on Earth, there are creatures that survive in extreme cold, heat... ...even in the deepest ocean trenchesIt's as though life is a virus.It adapts, spreadsMaybe 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 goingOlympus Mons, named after the home of the Greek godsA vast ancient volcano.Three times higher than Everest.There's no sign of activity.Since its discovery in the 1970s, it's been declared extinctHang 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 sleepingThere could be magma flowing beneath the crust right now......building up, waiting to be unleashedVolcanic activity could be melting frozen water in the soil......pumping gases into the atmosphere, recycling minerals and nutrients Creating all the conditions needed for lifeThis makes the Grand canyon look like a crack in the sidewalkEndless 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 waterAnd where there's water, there could be lifeThe 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 lifeLook 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 nowWater that could be sustaining Martian lifeNow, all we have to do is find itMaybe we've already found what we're looking for on EarthSome think that life started here and then migrated to EarthAn asteroid impact could've blasted fragments of Mars...plete with tiny microbes out into space......and onto the young Earth where they sowed the seeds of lifeNo wonder we find Mars fascinating, this could be our ancestral homeIt could be we are all MartiansThe 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 aheadOur 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 gameBut these are all too real.Asteroids, some of them hundreds of miles wideThis one must be about 20 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 rightRubble like this came together to make the planets......including our ownPretty 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 planetSomething must have stopped themSomething powerful.Jupiter.What a monsterAt least a thousand time bigger than Earth......so vast you could fit all the other planets inside itSomething this massive dominates its neighborsIts gravity is pulling the asteroids apartAnd it's breathtakingBut 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 violenceIt'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 SpotThe 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 stormJust one bolt is 10,000 times more intense than any at home.Looks like the safest place to see Jupiter is from a distanceUp there at the poles......those dancing lights, they're like the auroras back home.But the Geiger counter is going wildEven these are deadly, generated by lethal radiationOut here, nothing is what it seems.The universe is full of terrors, traps.Maybe this is a safe haven, the multi-colored moon, IoWrongVery 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 imaginationFour hundred million miles from Earth......flying a commercial airliner here would take nearly a centuryWhat a weird looking place......and yet, strangely familiarA bit like the Arctic, with all that ice, all those ridges and cracksIt'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 solidUnless, Jupiter's gravity is creating friction deep inside......heating the ice into water, allowing life to develop in the water... ...beneath its frozen crust.We might be feet away from aliensFrom 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 reachIt's captivated our imaginations, haunted our dreamsAnd here it is, spinning before our eyesSaturn.Named for the Roman god......who reigned over an golden age of peace and harmonyThis planet's a giant ball of gas, so light it would float on waterIts spectacular rings would stretch almost from Earth to the Moon. There's the Cassini orbiterIt's picking up ghostly radio emissionsProbably generated by auroras around Saturn's polesThis is the real music of the spheres.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 destructionBillions of shards of iceSome as small as ice cubes, others the size of houses.They collide, break apart, reassembleIt's like a snapshot of our early solar system......as dust and gas orbited the newly born Sun...and gravity worked this magic pulling the lumps together......until from space trash like this, our home emergedWe could stay here foreverBut 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 hereThere's wind, rain ,even seasonsRivers, lakes and oceansIt looks so familiar, so similar to Earth.But that's not water, it's liquid natural gasHundreds 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 alreadyThe Huygens space probe is here to find outIt's telling us there's organic material in the soil.But it's so cold, minus 300 degreesThere's no way life could developUnless Titan warms up.The Sun is supposed to get hotterWhen it does maybe life will spring up here......just like it did on EarthAnd as the Earth gets too hot for us, maybe we'll move to Titan.One day, we might call this distant land homeHome.We're at least 700 million miles away now.After this we lose visual contact with Earth.We're standing on a cliffLooking 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 historyIt's like diving into the depths of the oceanThose rings make it look like Uranus has been tilted off its axis...toppled over by a stray planetIt's eerie out here.Already beginning to feel small, lonelyMaybe this is how we'll feel at the edge of the universeBut we've barely left the shoreIf 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, NeptuneThis world is covered in methane gasAnd a storm as big as Earth......whipped up by savage thousand mile-an-hour windsBack home, it's the Sun that drives the wind......But Neptune's far away.Something else must be creating these ferocious windsBut what?We know very little about our own solar system.After all those balls of gas a solid moon...Triton.Solid but not stableJust 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 loseNeptune's massive gravity is pulling on Triton.Slowing it down, reeling it inOne day, it will be ripped apart by NeptuneAnd that's itNo 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 voidIt's teeming with frozen rocks.Like Pluto.Until recently, we thought Pluto was alone.Beyond it, nothingWe were wrongMore frozen worldsDiscoveries so new nobody can agree what to call themPlutinos, ice dwarves, cubewanosOur 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 2003Its 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 record in different languagesAnd a map showing how to find our home solar systemThe 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 hurting towards the EarthAnd seeding all this ice, maybe comets carried water to Earth tooThe 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 universeInterstellar space.Billions of stars like our own Sun......many with planets, many of those with moons.It's hard to know which way to goThere 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're only just reached the first solar system beyond...Alpha CentauriNot one but three stars.Spinning around each other locked in a celestial standoffEach 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 overfour light-years from home.Distances so vast they're mind-bogglingWho knows what strange forces lie ahead...what we'll discover when--If we reach the edge of the universeTen light years from Earth, the star Epsilon EridaniSpectacular rings of dust and iceAnd somewhere in there, planets forming out of debris......being born before our eyes.Asteroids and comets everywhereWe 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 bestThere must be more mature solar systems out here......But finding them is like looking for a needle in a cosmic haystackTwenty light years from Earth.Star Gliese 581It's about the same age as our sun.This planet is just the right distance from its sunAny closer and water would boil away, any further and it would freeze Ideal conditions for life to emergeAnd 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 nowThey could be tuning into our TV signals......watching shows from 20 years ago.But until we devise a way of communicating......over these vast distances, all we can do is speculateUs and them, living parallel lives......unaware of each other's existence.Unless life has come and goneThat's the problem with comets.They're creators and destroyers......as the dinosaurs the hard wayThis 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...lions 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 exitThat's how we tracked down Bellerophon in the 1990's......and hundreds of other distant planetsSixty-five light years from Earth......turn on your TV here and you'd pick up Hitler's Berlin Olympics The twin stars of Algol.Known to the ancients as the demon starFrom 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 otherAlmost 100 light years from home......faint whispers from one of the first ever radio broadcastsFrom here on out, it's as if the Earth never existedFeels like a life time since we stood on that beach......looking up at the sky, wondering where and how we fit inWe've learned one thing for sureThe universe is too bizarre, too startling......for us to guess what lies aheadDeep inside our galaxy, the Milky WayPinpricks of light that have inspired a thousand and one talesThe Seven Sisters, the daughters of the ancient Greek god, Atlas ...transformed into star to comfort their father......as he held the heavens on his shouldersAnd this giant, BetelgeuseThe brightest, biggest star we've seen so far.Six hundred times wider than our sunBut 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 cloudDust and gas shrouding usThere, 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 degreesSo hot, it's beginning to trigger nuclear reactions......the kind that keep our sun shining......making energy, radiation, lightA star is being born.Orion's dark cloud is a vast star factoryWe'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 rightJets of gas exploding out with tremendous force......blasting dust and gas out for millions of miles.It's unbelievably violent and creativeNebula......vast glowing clouds of gas hanging in space.With no wind out here, they'll take thousands of years to disperseThey seem to be forming a vast stellar sculpture.Nature is more than a scientist, an engineer......it's an artist on the grandest of scalesAnd this is a masterpieceStars 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 deathGreen and violet, hydrogen and helium......the raw materials of the universe.Red and blue, nitrogen and oxygen......the building blocks of life on EarthFor us to live, stars like this had to dieEvery 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 starsOur family tree begins hereAt its heart, the ghost of a star......a white swarfWhite, hot, small......but unbelievably denseIn 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 dwarfIts death will herald the end of life on earthMakes you wonder how many other world have come and gone......celestial stories left untold, lost forever.But the greatest story of them all is still to be toldWe must go back through time to the very first chapter......to learn how the universe began.The scattered remains of dead star......the Crab NebulaSix thousand light years from home, deep inside a stellar graveyardWe've learnt so much...seen things we'd never have believed possibleNow, sights like this, wonders once beyond imagination......we take in our strideWe're ready to face whatever lies aheadDetermined to reach the edge of the universeThis is the calm after the storm, after an massive explosion......a supernova that turned a star into dust and gasThe eye of the storm.A spinning pulsating star, a pulsar.The gravity has squeezed the giant star's core down to thisIt's just 12 miles across, unimaginably denseOne pinhead of this would weigh hundreds...。