Cosmos 8

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52667||57502||SAGAN: We are drifting in\~a great ocean of space and time.|| 59207||62108||In that ocean, the events\~that shape the future...|| 62310||64710||...are working themselves out.|| 66915||70248||Each creature and every world,\~to the remotest star...|| 70451||72351||...owe their existence to...|| 72554||75387||...the great, coursing,\~implacable forces of nature...|| 75590||78718||...but also, to minor happenstance.|| 81262||84527||We are carried with our planet\~around the sun.|| 8473
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  52667||57502||SAGAN: We are drifting in\~a great ocean of space and time.||59207||62108||In that ocean, the events\~that shape the future...||62310||64710||...are working themselves out.||66915||70248||Each creature and every world,\~to the remotest star...||70451||72351||...owe their existence to...||72554||75387||...the great, coursing,\~implacable forces of nature...||75590||78718||...but also, to minor happenstance.||81262||84527||We are carried with our planet\~around the sun.||84732||88168||The Earth has made more than\~4 billion circuits of our star...||88369||90200||...since its srcin.||92240||96142||The sun itself travels about\~the core of the Milky Way galaxy.||96344||98972||Our galaxy is moving\~among the other galaxies.||99180||102547||We have always been space travelers.||104352||109221||These fine sand grains are all,\~more or less, uniform in size.||110124||113355||They're produced from bigger rocks\~through ages of...||113561||117395||...jostling and rubbing,\~abrasion and erosion.||117599||121467||Driven in part by\~the distant moon and sun.||121803||125364||So the roots of the present\~lie buried in the past.||125573||129339||We are also travelers in time.||133815||135043||But trapped on Earth...||135249||138582||...we've had little to say about\~where we go in time and space...||138786||140151||...or how fast.||140355||144086||But now we're thinking\~about true journeys in time...||144292||148194||...and real voyages\~to the distant stars.||149964||154560||A handful of sand contains\~about 10,000 grains...||154769||156964||...more than all the stars\~we can see...||157171||159503||...with the naked eye\~on a clear night.||159707||161800||But the number of stars we can see...||162010||165605||...is only the tiniest fraction\~of the number of stars that are.||166414||169440||What we see at night\~is the merest smattering...||169651||171619||...of the nearest stars...||171819||176085||...with a few more distant bright\~stars thrown in for good measure.||176290||180158||Meanwhile, the cosmos\~is rich beyond measure.||180361||182488||The number of stars\~in the universe...||182697||186030||...is larger than all the grains\~of sand on all the beaches...||186234||187826||...of the planet Earth.||191706||196507||Long ago, before we had figured out\~that the stars are distant suns...||196711||199839||...they seemed to us\~to make pictures in the sky.||200048||202846||Just follow the dots.||204152||207315||The Big Dipper constellation\~today in North America...||207522||209683||...has had many other incarnations.||209891||212155||Every culture, ancient and modern...||212427||216193||...has placed its totems\~and concerns among the stars.||216397||220390||From a Chinese bureaucrat\~to a German wagon.||224439||228239||But very ancient cultures would have\~seen different constellations...||228443||231742||...because the stars move\~with respect to one another.||231946||236713||We can give a computer the present\~positions and motions of stars...||236918||240615||...and then run the patterns\~back into time.||242623||246320||Every constellation is a single frame\~in a cosmic movie...||246527||248893||...but because our lives\~are so short...||  249097||251088||...because star patterns\~change slowly...||251299||254234||...we tend not to notice\~it's a movie.||254435||258235||A million years ago,\~there was no Big Dipper.||258639||261938||Our ancestors, looking up\~and wondering about the stars...||262143||265772||...saw some other pattern\~in the northern skies.||266814||271183||We can also run a constellation,\~Leo the Lion, say, forward in time...||271385||275287||...and see what the patterns\~in the stars will be in the future.||277058||279458||A million years from now,\~Leo might be renamed...||279660||282356||...the constellation\~of the Radio Telescope.||282563||285862||Although I suspect radio telescopes\~then will be as obsolete...||286067||287967||...as stone spears are now.||288169||292196||Or, here's the constellation\~of Cetus the Whale.||301215||305948||A million years ago, it may have\~been called something else.||306154||307644||Perhaps the Spear.||312760||317288||Now, let's run fast-forward\~through a billion nights.||322436||324063||Millions of years from now...||324272||328470||...some other very different image\~will be featured in this cosmicmovie.||336417||339443||In Orion the Hunter,\~things are changing...||339654||341588||...not only because\~the stars are moving...||341789||344553||...but also because\~the stars are evolving.||344759||348320||Many of Orion's stars are\~hot, young and short-lived.||348529||352590||They're born, live and die within\~a span of only a few million years.||352800||355633||If we run Orion forward in time...||355837||358670||...we see the births\~and explosive deaths...||358873||360397||...of dozens of stars...||360608||364738||...flashing on and winking off\~like fireflies in the night.||367181||370708||If we wait long enough,\~we see the constellations change.||370918||374854||But if we go far enough,\~we also see the star patterns alter.||375056||376921||Two-dimensional constellations...||377124||381117||...are only the appearance of stars\~strewn through three dimensions.||381329||385629||Some are dim and near,\~others are bright but farther away.||386868||389200||Could a space traveler\~actually see...||389403||392099||...the patterns of\~the constellations change?||392306||397175||For that, you must travel roughly as\~far as the constellation is from us.||397645||400671||Here, we're traveling\~hundreds of light-years...||400882||405182||...circling all the way around\~the stars of the Big Dipper.||408723||410850||Inhabitants of planets\~around other stars...||411058||413492||...will see different constellations\~than us...||413694||416663||...because their vantage points\~are different.||424739||428402||Here we are\~in the constellation Andromeda...||428609||433410||...or at least a model of it\~next to the constellation Perseus.||433614||435775||Andromeda, in the Greek myth...||435983||439783||...was the maiden\~who was saved by Perseus...||439987||441921||...from a sea monster.||442123||447026||This star just above me\~is Beta Andromedae...||447228||449856||...the second brightest star\~in the constellation...||450064||453227||...75 light-years from the Earth.||453434||456528||The light by which we see this star...||456737||460867||...has spent 75 years\~traversing interstellar space...||  461075||463066||...on its journey to the Earth.||463277||466872||In the unlikely event\~that Beta Andromedae...||467081||469606||...blew itself up\~a week ago Tuesday...||469817||472581||...we will not know of it\~for another 75 years...||472787||476780||...as this interesting information,\~traveling at the speed of light...||476991||480620||...crosses the enormous\~interstellar distances.||480828||483319||When the light we see\~from this star set out...||483531||486261||...on its long\~interstellar voyage...||486467||489027||...the young Albert Einstein...||489236||492103||...working as a Swiss patent clerk...||492306||496208||...had just published his epochal\~special theory of relativity...||496410||497741||...here on Earth.||498612||499840||We see...||500047||504177||...that space and time\~are intertwined.||504385||507252||We cannot look out into space...||507455||510754||...without looking back into time.||511025||514119||The speed of light is very fast...||514328||517525||...but space is very empty...||517732||521031||...and the stars are very far apart.||521235||524363||The distances that we've been\~talking about up to now...||524572||528372||...are very small\~by the usual astronomical standards.||528576||531204||In fact, the distance\~from the Earth...||531412||533403||...to the center\~of the Milky Way galaxy...||533614||536481||...is 30,000 light-years.||537451||542388||From our galaxy to the nearest\~spiral galaxy like our own...||542723||544520||...called M31 ...||544725||547626||...and which is also within,\~that means behind...||547828||549796||...the constellation Andromeda...||550531||554262||...is 2 million light-years.||555503||558700||When the light we see today\~from M31 ...||558906||561431||...left on its journey for Earth...||561642||563576||...there were no human beings...||563778||567077||...although our ancestors\~were nicely evolving...||567281||570341||...and very rapidly,\~to our present form.||571018||573509||There are much greater distances\~in astronomy.||573721||577316||The distance from the Earth\~to the most distant quasars...||577525||580961||...is 8 or 10 billion light-years.||581162||585861||We see them as they were before\~the Earth itself accumulated...||586067||589628||...before the Milky Way galaxy\~was formed.||589837||593466||The fastest space vehicles ever\~launched by the human species...||593674||595608||...are the Voyager spacecraft.||595810||597505||They are traveling so fast...||597711||601306||...that it's only\~10,000 times slower...||601816||603113||...than the speed of light.||603317||605945||The Voyager spacecraft\~will take 40,000 years...||606153||608212||...to go the distance\~to the nearest stars...||608422||611619||...and they're not even headed\~towards the nearest stars.||611826||614420||But is there a method\~by which we could travel...||614628||618120||...in a conveniently short time\~to the stars?||618332||621165||Can we travel close\~to the speed of light?||  621368||624098||And what's magic\~about the speed of light?||624305||626899||Can't we travel faster than that?||628909||632743||It turns out that\~there is something very strange...||632947||634414||...about the speed of light.||634615||636674||Something that provides the key...||636884||640285||...to our understanding\~of time and space.||642022||643717||The story of its discovery...||643924||647519||...takes us to Tuscany\~in northern Italy.||649830||652264||There's something timeless\~about this place.||652466||656129||A century ago, it probably\~looked very much the same.||668249||672447||If you had traveled these roads\~in the summer of 1895...||672653||676783||...you might have come upon a\~16-year-old German high-schooldropout.||676991||680154||His teacher told him that\~he'd never amount to anything...||680361||683819||...that his attitude destroyed\~classroom discipline...||684031||685760||...that he should drop out.||685966||687957||So he left and came here...||688169||690603||...where he enjoyed\~wandering these roads...||690804||693272||...and giving his mind\~free rein to explore.||695276||697744||One day, he began\~to think about light...||697945||699936||...about how fast it travels.||700147||703207||We always measure\~the speed of a moving object...||703417||705385||...relative to something else.||705586||709613||I'm moving at about 10 kilometers\~an hour relative to the ground.||709823||711450||But the ground isn't at rest.||711659||715425||The Earth is turning at more\~than 1600 kilometers an hour.||715629||718097||The Earth itself is\~in orbit around the sun.||718299||722360||The sun is moving among\~the drifting stars, and so on.||722570||725971||It was hard for the young man\~to imagine some absolute standard...||726173||729040||...to measure all these\~relative motions against.||738852||742720||He knew that sound waves are\~a vibration of the air...||742923||746086||...and their speed is measured\~relative to the air itself.||746293||749490||But sunlight travels across\~the vacuum of empty space.||749697||751961|| Do light waves move\~relative to something else?||752166||755761||And if so, he wondered,\~ relative to what? ||759306||763436||That teenage dropout's name...||764111||765772||...was Albert Einstein.||765980||768915||And his ruminations changed the world.||774255||778385||He had been fascinated\~by Bernstein's 1869...||779260||782855||...People's Book of Natural Science.||783063||786226||Here, on its very first page...||787101||791231||...it describes the astonishing speed\~of electricity through wires...||791572||793506||...and light through space.||793841||797777||Einstein wondered, perhaps for\~the first time, in northern Italy...||798545||802743||...what the world would look like if\~you could travel on a wave of light.||803317||805512||To travel at the speed of light.||805719||810520||What an engaging and magical thought\~for a teenage boy on the road...||810724||814592||...where the countryside is dappled\~and rippling in sunlight.||
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