{0}{64}Now, on NOVA,
{65}{112}take a thrill ride into a world
{113}{173}stranger than science fiction,
{174}{233}where you play the game|by breaking some rules,
{234}{293}where a new view of the universe
{295}{330}pushes you beyond the limits
{331}{365}of your wildest imagination.
{389}{472}This is the world of "string theory,"
{473}{556}a way of describing|every force and all matter
{557}{640}from an atom to earth, to|the end of the galaxies--
{641}{736}from the birth of|time to its final tick,
{760}{855}in a single theory, a|"Theory of Everything."
{856}{940}Our guide to this brave new world
{940}{1036}is Brian Greene, the|bestselling author and physicist.
{1048}{1108}BRIAN GREENE And|no matter how many times I come here,
{1109}{1155}I never seem to get used to it.
{1156}{1204}NARRATOR: Can he help us solve
{1205}{1252}the greatest puzzle|of modern physics--
{1324}{1383}that our understanding of the universe
{1384}{1444}is based on two sets of|laws that don't agree?
{1492}{1588}NARRATOR: Resolving that|contradiction eluded even Einstein,
{1588}{1648}who made it his final quest.
{1660}{1695}After decades,
{1696}{1768}we may finally be on the|verge of a breakthrough.
{1864}{1924}The solution is strings,
{1936}{1983}tiny bits of energy
{1984}{2031}vibrating like the strings on a cello,
{2043}{2091}a cosmic symphony
{2091}{2139}at the heart of all reality.
{2187}{2234}But it comes at a price:
{2235}{2319}parallel universes and 11 dimensions,
{2331}{2355}most of which
{2355}{2378}you've never seen.
{2379}{2427}BRIAN GREENE: We really|may live in a universe
{2428}{2499}with more dimensions than meet the eye.
{2500}{2546}AMANDA PEET|People who have said that there were
{2547}{2582}extra dimensions of space
{2583}{2637}have been labeled crackpots,|or people who are bananas.
{2638}{2691}NARRATOR: A mirage of|science and mathematics
{2703}{2763}or the ultimate theory of everything?
{2792}{2838}S. JAMES GATES, JR. If string theory fails to provide
{2838}{2883}a testable prediction,
{2885}{2943}then nobody should believe it.
{2955}{2991}SHELDON LEE GLASHOW Is that a theory of physics,
{2992}{3026}or a philosophy?
{3027}{3087}BRIAN GREENE: One thing that|is certain is that string theory
{3088}{3135}is already showing us
{3147}{3194}that the universe may be a lot stranger
{3195}{3243}than any of us ever imagined.
{3250}{3291}NARRATOR: Coming up tonight,
{3303}{3363}the undeniable pull of strings.
{3368}{3423}BRIAN GREENE: The|atmosphere was electric.
{3428}{3464}String theory goes through
{3464}{3495}a revolution of its own...
{3502}{3542}MICHAEL DUFF|Five different string theories...
{3543}{3615}BRIAN GREENE:...and reveals|the new shape of things to come.
{3615}{3710}SAVAS DIMOPOULOS|Perhaps we live on a threedimensional membrane.
{3715}{3782}BRIAN GREENE: Our universe|might be like a slice of bread.
{3787}{3854}We're trapped on just a tiny slice
{3855}{3903}of the higher dimensional universe.
{3914}{3950}ALAN GUTH That's actually a problem.
{3950}{4010}NARRATOR: Watch the|Elegant Universe right now.
{6432}{6492}THE ELEGANT UNIVERSE
{6504}{6552}Hosted By Brian Greene
{6768}{6864}Welcome to the 11th Dimension
{6888}{6983}The Wild West of Physics
{7072}{7139}BRIAN GREENE: Imagine that|we were able to control space
{7187}{7235}or control time.
{7307}{7391}The kinds of things that we'd|be able to do would be amazing.
{7451}{7499}I might be able to go from here...
{7559}{7607}to here...
{7655}{7691}to here...
{7743}{7775}to here...
{7811}{7883}and over to here in only an instant.
{7887}{7966}Now, we all think that this|kind of trip would be impossible.
{7979}{8015}And it probably is.
{8027}{8079}But in the last few years, our ideas
{8079}{8146}about the true nature of space and time
{8147}{8194}have been going through some changes.
{8194}{8254}And things that used to|seem like science fiction
{8255}{8314}are looking|not-so-far-fetched.
{8326}{8398}It's all thanks to a|revolution in physics called
{8399}{8433}"string theory,"
{8434}{8482}which is offering a|whole new perspective
{8483}{8530}on the inner workings of the universe.
{8557}{8602}JOSEPH LYKKEN String|theory holds out the promise
{8603}{8651}that we can really understand
{8651}{8705}questions of why the universe
{8706}{8758}is the way it is at the|most fundamental level.
{8770}{8808}DAVID GROSS String theory is really
{8809}{8842}the Wild West of physics.
{8849}{8914}MICHAEL B. GREEN|This is an area of theoretical physics
{8926}{9010}which is so radically different|from anything that's been before.
{9022}{9106}BRIAN GREENE: This radical new|theory starts with a simple premise:
{9107}{9154}that everything in the universe,
{9154}{9201}the Earth, these buildings,
{9202}{9274}even forces like|gravity and electricity,
{9275}{9334}are made up of incredibly tiny,
{9335}{9382}vibrating strands of energy
{9383}{9430}called "strings."
{9442}{9481}And small as they are,
{9482}{9520}strings are changing everything
{9521}{9574}we thought we knew about the universe,
{9574}{9616}especially our ideas
{9617}{9657}about the nature of space.
{9710}{9738}To see how,
{9739}{9787}let's first shrink all of space
{9788}{9835}to a more manageable size.
{9885}{9943}Imagine that the whole|universe consisted
{9944}{10003}of nothing more than my hometown,
{10008}{10039}Manhattan.
{10060}{10128}So now, just one|borough of New York City
{10128}{10195}makes up the entire fabric of space.
{10231}{10254}And just for kicks,
{10255}{10307}let's also imagine that I'm the CEO
{10308}{10363}of a large corporation|with offices on Wall Street.
{10380}{10428}And because time is|money, I need to find
{10428}{10468}the quickest route from my apartment,
{10468}{10511}here in upper Manhattan
{10512}{10555}to my offices in lower Manhattan.
{10624}{10673}Now, we all know that|the shortest distance
{10674}{10722}between two points is a straight line,
{10727}{10770}but even if|there's no traffic--
{10770}{10842}a bit of a stretch even in|our imaginary Manhattan--
{10843}{10914}it'll still take us some|amount of time to get there.
{10998}{11034}By going faster and faster,
{11034}{11082}we can reduce the travel time.
{11083}{11125}But because nothing can go faster
{11125}{11171}than the speed of light,|there is a definite limit
{11172}{11217}to how much time we can cut
{11217}{11238}from our journey.
{11418}{11465}This Manhattan Universe fits with
{11466}{11544}an old, classical vision of space,
{11545}{11622}basically a flat grid|that's static and unchanging.
{11670}{11706}But when Albert Einstein looked
{11706}{11748}at the fabric of space,
{11749}{11790}he saw something completely different.
{11850}{11898}He said that space wasn't static;
{11899}{11946}it could warp and stretch.
{11998}{12066}And there could even be|unusual structures of space
{12078}{12125}called "wormholes."
{12126}{12197}A wormhole is a bridge or tunnel
{12197}{12257}that can link distant regions of space,
{12269}{12329}in effect, a cosmic shortcut.
{12420}{12473}In this kind of universe, my commute
{12473}{12521}would be a New Yorker's dream.
{12593}{12640}But there's a hitch:
{12641}{12676}to create a wormhole,
{12677}{12725}you've got to rip
{12726}{12773}or tear a hole in the fabric of space.
{12804}{12845}But can the fabric of space
{12846}{12868}really rip?
{12869}{12917}Can this first step toward forming
{12918}{12965}a wormhole actually happen?
{12982}{13025}Well, you can't answer these questions
{13025}{13073}on an empty stomach.
{13274}{13325}Turns out that by|looking at my breakfast--
{13326}{13360}coffee and|a doughnut--
{13361}{13408}we can get a pretty good sense
{13409}{13457}of what string theory says about
{13458}{13505}whether the fabric of space can tear.
{13553}{13625}Imagine that space is|shaped like this doughnut.
{13636}{13684}You might think that it|would be very different
{13685}{13732}from a region of space shaped
{13733}{13780}like this coffee cup.
{13793}{13840}But there's a precise sense
{13841}{13900}in which the shape of the|doughnut and the coffee cup
{13901}{13949}are actually the same,
{13950}{13996}just a little disguised.
{14025}{14092}You see, they both have one hole.
{14102}{14145}In the doughnut it's in the middle
{14152}{14212}and in the coffee cup|it's in the handle.
{14248}{14314}That means we can change the doughnut
{14315}{14389}into the shape of a|coffee cup and back again
{14390}{14464}without having to rip|or tear the dough at all.
{14476}{14535}Okay, but suppose you want to change
{14536}{14620}the shape of this doughnut|into a very different shape,
{14621}{14663}a shape with no holes.
{14675}{14764}The only way to do that is|to tear the doughnut like this
{14843}{14896}and then re-shape it.
{15040}{15075}Unfortunately,
{15076}{15147}according to Einstein's|laws, this is impossible.
{15164}{15231}They say that space|can stretch and warp,
{15232}{15267}but it cannot rip.
{15346}{15382}Wormholes might exist somewhere
{15383}{15423}fully formed,
{15424}{15459}but you could not rip space
{15459}{15555}to create a new one, over|Manhattan or anywhere else.
{15567}{15591}In other words,
{15596}{15663}I can't take a wormhole to work.
{15730}{15787}But now string theory is giving us
{15787}{15843}a whole new perspective on space,
{15855}{15902}and it's showing us that Einstein
{15903}{15951}wasn't always right.
{15963}{16023}To see how, let's|take a much closer look
{16023}{16059}at the spatial fabric.
{16143}{16214}If we could shrink down|to about a millionth
{16215}{16274}of a billionth of our normal size,
{16275}{16347}we'd enter the world|of quantum mechanics,
{16411}{16491}the laws that control how atoms behave.
{16534}{16622}It's the world of light and electricity
{16622}{16694}and everything else that operates|at the smallest of scales.
{16730}{16814}Here, the fabric of space|is random and chaotic.
{16905}{16970}Rips and tears might be commonplace.
{17018}{17090}But if they were, what would stop a rip
{17090}{17150}in the fabric of space from creating
{17160}{17208}a cosmic catastrophe?
{17304}{17320}Well,
{17320}{17392}this is where the power|of strings comes in.
{17416}{17464}Strings calm the chaos.
{17493}{17530}And as a single string
{17531}{17567}dances through space,
{17568}{17615}it sweeps out a tube.
{17687}{17747}The tube can act like a bubble
{17748}{17795}that surrounds the tear,
{17795}{17879}a protective shield with|profound implications.
{17946}{17982}Strings actually
{17982}{18042}make it possible for space to rip.
{18150}{18197}Which means that space
{18198}{18251}is far more dynamic and changeable
{18252}{18304}than even Albert Einstein thought.
{18311}{18358}So does that mean
{18359}{18407}that wormholes are possible?
{18443}{18515}Will I ever be able to|take a stroll on Everest,
{18558}{18623}grab a baguette in Paris
{18671}{18715}and still make it back to New York
{18716}{18759}in time for my morning meeting?
{18760}{18802}It would be kind of cool,
{18803}{18863}though it's still a|very distant possibility.
{18875}{18917}But one thing that is certain
{18918}{18946}is that string theory
{18946}{18994}is already showing us that the universe
{18995}{19034}may be a lot stranger
{19035}{19071}than any of us
{19072}{19107}ever imagined.
{19131}{19186}For example, string theory says
{19186}{19258}we're surrounded by hidden dimensions,
{19266}{19322}mysterious places beyond the familiar
{19323}{19378}three-dimensional space we know.
{19477}{19502}AMANDA PEET: People who've said
{19503}{19546}that there were extra|dimensions of space,
{19547}{19593}have been labeled as, you know,
{19594}{19641}crackpots or people who are bananas.
{19642}{19690}I mean, what, do you think|there are extra dimensions?
{19691}{19714}Well,
{19714}{19762}string theory really predicts it.
{19774}{19822}BRIAN GREENE: What we|think of as our universe
{19823}{19870}could just be one small part
{19871}{19918}of something much bigger.
{19954}{20050}SAVAS DIMOPOULOS: Perhaps|we live on a membrane,
{20051}{20102}a threedimensional membrane
{20103}{20186}that floats inside|higher dimensional space.
{20206}{20278}BRIAN GREENE: There could be|entire worlds right next to us,
{20278}{20326}but completely invisible.
{20373}{20433}NIMA ARKANI-HAMED These|other worlds would, in a very literal sense, be,
{20434}{20481}be parallel universes.
{20482}{20530}This isn't a particularly exotic
{20530}{20578}or, or strange notion.
{20625}{20671}BRIAN GREENE: No wonder physics students
{20672}{20716}are lining up to explore
{20717}{20769}the strange world of string theory.
{20808}{20855}SHELDON LEE GLASHOW: String|theory is very active.
{20856}{20928}Things are happening. There|are a lot of people doing it.
{20947}{21008}Most of the young|kids, given the choice,
{21009}{21069}at a ratio of something like ten to one,
{21069}{21117}they will go into string theory.
{21153}{21225}BRIAN GREENE: But strings|weren't always this popular.
{21261}{21309}The Potential of Strings
{21465}{21549}The pioneers of string|theory struggled for years,
{21550}{21597}working alone on an idea
{21598}{21645}that nobody else believed in.
{21688}{21729}Here's the gist of it:
{21741}{21786}for decades, physicists believed
{21787}{21831}that the tiniest bits inside an atom
{21832}{21884}were point particles.
{21909}{21993}Flying around the outside|were the electrons,
{21993}{22053}and inside were protons and neutrons
{22054}{22112}which were made up of quarks.
{22148}{22184}But string theory says
{22184}{22244}that what we thought|were indivisible particles
{22245}{22352}are actually tiny, vibrating strings.
{22393}{22466}BURT OVRUT It's|nothing really mystical. It's a really tiny string.
{22467}{22556}It either closes in to its little|circle or it has end points,
{22557}{22604}but it's just a little string.
{22705}{22784}BRIAN GREENE: In the|1980s, the idea caught on,
{22784}{22868}and people started jumping|on the string bandwagon.
{22899}{22937}MICHAEL B. GREEN: Well, the fact|that suddenly all these other
{22938}{22975}people were working in the field
{22976}{23024}had its advantages|and its disadvantages.
{23025}{23072}It was wonderful to see how
{23073}{23119}rapidly the subject could develop now,
{23120}{23180}because so many people|were working on it.
{23192}{23244}BRIAN GREENE: One of the|great attractions of strings
{23245}{23283}is their versatility.
{23455}{23503}Just as the strings on a cello
{23504}{23575}can vibrate at different frequencies,
{23576}{23647}making all the individual musical notes,
{23659}{23743}in the same way, the tiny|strings of string theory
{23744}{23816}vibrate and dance in different patterns,
{23816}{23887}creating all the fundamental particles
{23888}{23935}of nature.
{23981}{24030}If this view is right,
{24031}{24103}then put them all together|and we get the grand
{24104}{24175}and beautiful symphony|that is our universe.
{24230}{24283}What's really exciting about this
{24290}{24355}is that it offers an|amazing possibility.
{24384}{24428}If we could only master
{24429}{24472}the rhythms of strings,
{24472}{24544}then we'd stand a good|chance of explaining
{24545}{24616}all the matter and all|the forces of nature,
{24640}{24712}from the tiniest subatomic particles
{24713}{24784}to the galaxies of outer space.
{24945}{25012}This is the potential of string theory,
{25013}{25084}to be a unified "Theory of Everything."
{25137}{25177}But, at first sight,
{25178}{25230}in our enthusiasm for this idea,
{25231}{25283}we seem to have gone too far.
{25444}{25516}Because we didn't produce|just one string theory,
{25516}{25564}or even|two--
{25583}{25647}we somehow managed to come up with five.
{25743}{25790}MICHAEL DUFF|Five different string theories,
{25791}{25862}each competing for the title|of the Theory of Everything.
{25863}{25935}BURT OVRUT: And if there's going to be|a "The Fundamental Theory of Nature,"
{25936}{25975}there ought to be one of them.
{25976}{26043}AMANDA PEET: I suppose a number|of string theorists thought,
{26043}{26103}"Ah, that's fantastic. That's wonderful.|And maybe one of these will end up
{26104}{26151}being the right theory of the world."
{26152}{26191}And yet, there must have been a little
{26192}{26235}nagging voice at the back of the head
{26236}{26283}that said, "Well, why are there five?"
{26331}{26378}BRIAN GREENE: With|five competing players,
{26379}{26427}the stage of string theory was
{26428}{26475}looking a little crowded.
{26494}{26568}The five theories had|many things in common.
{26569}{26643}For example, they all|involved vibrating strings,
{26662}{26712}but their mathematical details appeared
{26713}{26763}to be quite different.
{26787}{26858}Frankly, it was embarrassing.
{26859}{26907}How could this unified|Theory of Everything
{26908}{26955}come in five different flavors?
{26998}{27042}This was a case where more
{27043}{27086}was definitely less.
{27118}{27182}But then something remarkable happened.
{27218}{27266}Getting to One Theory
{27285}{27338}This is Ed Witten.
{27360}{27409}He's widely regarded as one
{27410}{27458}of the world's greatest|living physicists,
{27478}{27535}perhaps even Einstein's successor.
{27576}{27650}MICHAEL B. GREEN: Ed Witten is a|very special person in the field.
{27651}{27697}He clearly has a grasp,
{27698}{27770}particularly of the underlying|mathematical principles,
{27771}{27834}which is far greater|than most other people.
{27835}{27892}JOSEPH POLCHINSKI Well, you know, we all think we're very smart;
{27893}{27950}he's so much smarter|than the rest of us.
{27986}{28034}BRIAN GREENE: In 1995,
{28034}{28086}string theorists from all|over the world gathered
{28087}{28154}at the University of Southern California
{28155}{28213}for their annual conference.
{28214}{28274}Ed Witten showed up at Strings 95
{28275}{28334}and rocked their world.
{28362}{28398}EDWARD WITTEN I|was really trying to think of something would be
{28399}{28441}that significant for the occasion.
{28442}{28514}And actually, since five|string theories was too many,
{28514}{28561}I thought I would try to|get rid of some of them.
{28729}{28777}BRIAN GREENE: To solve the problem,
{28778}{28849}Witten constructed a|spectacular new way of
{28850}{28897}looking at string theory.
{28945}{29005}JOSEPH POLCHINSKI: Ed announced|that he had thought about it,
{29012}{29057}and moreover, he had solved it.
{29058}{29100}He was going to tell us the solution to
{29101}{29149}every string theory in every dimension,
{29161}{29208}which was an enormous claim,
{29209}{29275}but coming from Ed it|was not so surprising.
{29276}{29332}BRIAN GREENE: The atmosphere|was electric because,
{29333}{29389}all of a sudden, string theory,
{29389}{29433}which had been going|through a kind of doldrums,
{29434}{29478}was given an incredible boost,
{29479}{29508}a shot in the arm.
{29509}{29557}LEONARD SUSSKIND|Ed Witten gave his famous lecture.
{29567}{29629}And he said a couple of words|that got me interested...
{29636}{29688}and for the rest of the lecture...
{29689}{29749}I got hooked up on the|first few words that he said,
{29750}{29809}and completely missed|the point of his lecture.
{29821}{29881}NATHAN SEIBERG|I remember I had to give the talk after him,
{29881}{29929}and I was kind of embarrassed to.
{29929}{29994}JOSEPH LYKKEN: Ed Witten|just blew everybody away.
{29994}{30052}BRIAN GREENE: Ed Witten blew|everybody away because he
{30052}{30109}provided a completely new perspective
{30109}{30157}on string theory.
{30300}{30360}From this point of view, we could see
{30360}{30432}that there weren't really|five different theories.
{30456}{30528}Like reflections in a wall of mirrors,
{30540}{30600}what we thought were five theories
{30601}{30660}turned out to be just|five different ways
{30661}{30720}of looking at the same thing.
{30876}{30955}String theory was unified at last.
{30984}{31031}Witten's work sparked a breakthrough
{31032}{31116}so revolutionary that it|was given it's own name,
{31117}{31158}"M-theory,"
{31159}{31236}although no one really|knows what the M stands for.
{31248}{31284}S. JAMES GATES, JR.:|Aah, what is the M for?
{31291}{31392}ALL: M-theory.
{31394}{31461}STEVEN WEINBERG M-theory is a theory...
{31462}{31529}BURT OVRUT: I don't actually|know what the M stands for.
{31529}{31576}STEVEN WEINBERG: Well, the M has...
{31576}{31607}BURT OVRUT: I've heard|many descriptions.
{31608}{31660}STEVEN WEINBERG: Mystery|theory, magic theory...
{31661}{31680}JOSEPH LYKKEN: It's the Mother theory.
{31684}{31718}STEVEN WEINBERG: Matrix theory.
{31719}{31751}LEONARD SUSSKIND: Monstrous theory?
{31780}{31821}I don't know what it...I|don't know what Ed meant.
{31833}{31917}EDWARD WITTEN: M stands for magic,|mystery or matrix, according to taste.
{31941}{32012}SHELDON LEE GLASHOW:|I suspect that the "M"
{32013}{32070}is an upside down "W" for "Witten."
{32071}{32126}EDWARD WITTEN: Some cynics|have occasionally suggested
{32127}{32180}that M may also stand for "murky,"
{32181}{32236}because our level of|understanding of the theory is,
{32237}{32269}in fact, so primitive.
{32270}{32301}Maybe I shouldn't|have told you that one.
{32380}{32457}BRIAN GREENE: Whatever the|name, it was a bombshell.
{32464}{32529}Suddenly everything was different.
{32538}{32579}JOSEPH LYKKEN: There was a|lot of panic, if you like,
{32579}{32629}realizing that big|things were happening,
{32630}{32677}and all of us not|wanting to get left behind
{32677}{32725}in this new revolution of string theory.
{32754}{32797}BRIAN GREENE: After Witten's talk,
{32798}{32840}there was renewed hope
{32840}{32888}that this one theory could be
{32888}{32960}the theory to explain|everything in the universe.
{32968}{33032}But there was also a price to pay.
{33063}{33115}Before M-theory, strings seemed
{33116}{33188}to operate in a world|with 10 dimensions.
{33188}{33257}These included one dimension of time,
{33258}{33325}the three familiar space dimensions,
{33326}{33387}as well as six extra dimensions,
{33388}{33439}curled up so tiny
{33440}{33488}that they're completely invisible.
{33500}{33552}GARY HOROWITZ: Well, we think|these extra dimensions exist
{33553}{33618}because they come out of the|equations of string theory.
{33620}{33668}Strings need to move in more
{33669}{33716}than three dimensions.
{33740}{33812}And that was a shock to everybody,
{33812}{33860}but then we learned to live with it.
{33862}{33939}BRIAN GREENE: But M-theory|would go even further,
{33940}{34016}demanding yet another spatial dimension,
{34025}{34088}bringing the grand total to
{34089}{34136}11 dimensions.
{34164}{34244}BURT OVRUT: We know that there|would have to be 11 dimensions
{34244}{34292}for this theory to make sense.
{34293}{34339}So there must be 11 dimensions.
{34340}{34411}We only see three plus one of them.
{34412}{34447}How is that possible?
{34464}{34527}BRIAN GREENE: For most of|us, it's virtually impossible
{34528}{34603}to picture the extra, higher dimensions:
{34604}{34639}I can't.
{34656}{34686}And it's not surprising.
{34687}{34740}Our brains evolved sensing
{34741}{34783}just the three spatial dimensions
{34784}{34824}of everyday experience.
{34836}{34891}So how can we get a feel for them?
{34910}{34946}Parallel Universes
{34965}{35011}One way is to go to the movies.
{35395}{35443}THEATER BRIAN GREENE: We're|all familiar with the real world
{35444}{35491}having three spatial dimensions.
{35492}{35539}That is, anywhere I go,
{35540}{35605}I can move left-right,
{35606}{35671}back-forth,|or up-down.
{35675}{35743}MOVIE SCREEN BRIAN But in|the movies, things are a bit different.
{35798}{35854}Even though the characters|on a movie screen
{35855}{35907}look three-dimensional, they actually
{35907}{35958}are stuck in just two dimensions.
{35975}{36042}There is no back-forth|on a movie screen,
{36054}{36114}that's just an optical illusion.
{36203}{36231}To really move
{36232}{36275}in the back-forth dimension,
{36276}{36318}I'd have to step out of the screen.
{36342}{36378}And sometimes moving into
{36379}{36418}a higher dimension
{36419}{36457}can be a useful thing to do.
{36642}{36702}MOVIE SCREEN BRIAN GREENE So dimensions all have to do
{36703}{36743}with the independent directions
{36743}{36779}in which you can move.
{36779}{36828}They're sometimes called|"degrees of freedom."
{36829}{36906}THEATER BRIAN GREENE: The more|dimensions or degrees of freedom you have,
{36907}{36954}the more you can do. That's right.
{36966}{37037}BRIAN GREENE: And if there|really are 11 dimensions,
{37038}{37110}then strings can do a lot more, too.
{37134}{37181}BURT OVRUT: People found, fairly soon,
{37182}{37253}that there were objects|that lived in these theories,
{37254}{37344}which weren't just strings,|but were larger than that.
{37345}{37433}They actually looked like|membranes or surfaces.
{37469}{37529}BRIAN GREENE: The extra|dimension Witten added
{37529}{37589}allows a string to|stretch into something
{37589}{37649}like a membrane,
{37663}{37723}or a "brane" for short.
{37821}{37924}A brane could be|three-dimensional or even more.
{37929}{37971}And with enough energy,
{37972}{38044}a brane could grow to an enormous size,
{38068}{38140}perhaps even as large as a universe.
{38248}{38332}This was a revolution in string theory.
{38348}{38420}STEVEN WEINBERG: String theory|has gotten much more baroque.
{38420}{38492}I mean now there are not only|strings, there are membranes.
{38493}{38552}People go on calling this string theory,
{38553}{38612}but the string theorists|are not sure it really
{38613}{38656}is a theory of strings anymore.
{38704}{38751}BRIAN GREENE: The|existence of giant membranes
{38752}{38799}and extra dimensions
{38799}{38871}would open up a|startling new possibility,
{38891}{38933}that our whole universe
{38933}{38974}is living on a membrane,
{38974}{39022}inside a much larger,
{39023}{39063}higher dimensional space.
{39131}{39183}It's almost as if we|were living inside...
{39219}{39267}a loaf of bread?
{39675}{39759}Our universe might be|like a slice of bread,
{39760}{39794}just one slice,
{39795}{39842}in a much larger loaf
{39843}{39915}that physicists|sometimes call the "bulk."
{39915}{39962}And if these ideas are right,
{39963}{40010}the bulk may have other slices,
{40010}{40094}other universes, that|are right next to ours,
{40095}{40154}in effect, "parallel" universes.
{40179}{40238}Not only would our|universe be nothing special,
{40250}{40298}but we could have a lot of neighbors.
{40346}{40412}Some of them could|resemble our universe,
{40413}{40478}they might have matter|and planets and, who knows,
{40479}{40525}maybe even beings of a sort.
{40526}{40598}Others certainly would|be a lot stranger.
{40599}{40633}They might be ruled by
{40634}{40682}completely different laws of physics.
{40694}{40761}Now, all of these other|universes would exist
{40762}{40814}within the extra|dimensions of M-theory,
{40814}{40867}dimensions that are all around us.
{40869}{40921}Some even say they might be right
{40922}{40994}next to us, less than a millimeter away.
{41001}{41041}But if that's true,
{41042}{41114}why can't I see them or touch them?
{41138}{41178}BURT OVRUT: If you have a brane living
{41179}{41221}in a higher dimensional space,
{41221}{41262}and your particles, your atoms,
{41263}{41298}cannot get off the brane,
{41318}{41354}it's like trying to reach out,
{41354}{41399}but you can't touch anything.
{41423}{41507}It might as well be on the|other end of the universe.
{41562}{41634}JOSEPH LYKKEN: It's a very|powerful idea because if it's right
{41635}{41706}it means that our whole|picture of the universe
{41707}{41747}is clouded by the fact
{41748}{41795}that we're trapped on just a tiny slice
{41796}{41843}of the higher dimensional universe.
{41874}{41932}BRIAN GREENE: It is a|powerful idea, especially
{41932}{41988}because it may help solve one
{41989}{42037}of the great mysteries|of modern science.
{42059}{42095}Escaping Gravity
{42138}{42184}It has to do with gravity.
{42203}{42250}It's been more than 300 years
{42251}{42293}since Isaac Newton came up
{42294}{42338}with the universal law of gravity,
{42339}{42382}inspired, as the story goes,
{42383}{42443}by seeing an apple fall from a tree.
{42462}{42515}Today, it seems obvious that gravity
{42515}{42550}is a powerful force.
{42735}{42790}SHELDON LEE GLASHOW: It would|seem to most people that gravity is
{42790}{42836}a very important|force, it's very strong.
{42837}{42877}It's very hard to get up in the morning,
{42878}{42922}stand up, and when things fall
{42923}{42965}they break because gravity is strong.
{43001}{43053}But the fact of the matter|is that it's not strong.
{43054}{43114}It's, it's really a very weak force.
{43121}{43184}BRIAN GREENE: Gravity|pulls us down to the Earth,
{43185}{43246}and keeps our Earth in|orbit around the sun.
{43258}{43306}But in fact, we overcome the force
{43307}{43354}of gravity all the time.
{43354}{43390}It's not that hard.
{43438}{43498}Even with the gravity|of the entire Earth
{43499}{43538}pulling this apple downward,
{43539}{43576}the muscles in my arm
{43577}{43613}can easily overcome it.
{43614}{43648}And it's not just our muscles
{43649}{43685}that put gravity to shame.
{43692}{43750}Magnets can do it, too, no sweat.
{43807}{43858}Magnets carry a different force,
{43858}{43894}the electromagnetic force.
{43894}{43942}That's the same force behind light
{43943}{43990}and electricity.
{44050}{44122}It turns out that|electromagnetism is much,
{44122}{44182}much stronger than gravity.
{44241}{44289}Gravity, in comparison,
{44290}{44337}is amazingly weak.
{44338}{44373}How weak?
{44385}{44433}The electromagnetic force is some
{44434}{44482}thousand billion, billion, billion,
{44482}{44529}billion times stronger.
{44541}{44641}That's a one with 39|zeroes following it.
{44642}{44709}1.000.000.000.000.000.000.|000.000.000.000.000.000.000
{44733}{44793}The weakness of gravity
{44794}{44841}has confounded scientists for decades.
{44863}{44937}But now, with the radical|world of string theory,
{44938}{45009}filled with membranes|and extra dimensions,
{45016}{45093}there's a whole new way|to look at the problem.
{45124}{45176}NIMA ARKANI-HAMED: One way of|approaching the question of why gravity
{45177}{45243}is so weak compared to|all the other forces, is to
{45244}{45309}turn the question completely|on its head, and say,
{45309}{45356}"No, actually gravity isn't very weak.
{45357}{45429}Compared to all the other forces,|it just appears to be weak."
{45434}{45497}BRIAN GREENE: It may be|that gravity is actually
{45498}{45561}just as strong as electromagnetism,
{45561}{45603}but for some reason,
{45604}{45657}we can't feel its strength.
{45693}{45764}SAVAS DIMOPOULOS: Consider a pool table,
{45776}{45848}a very large pool table.
{45860}{45919}Think of the surface of the pool table
{45920}{45980}as representing our|three-dimensional universe,
{45980}{46028}although it is just two-dimensional,
{46055}{46100}and think of the billiard balls
{46112}{46172}as representing atoms
{46196}{46268}and other particles that|the universe is made out of.
{46323}{46371}BRIAN GREENE: So here's the wild idea:
{46381}{46420}the atoms and particles
{46421}{46459}that make up stuff|in the world around us
{46460}{46527}will stay on our particular membrane,
{46528}{46574}our slice of the universe
{46575}{46635}just as the billiard balls will stay
{46635}{46695}on the surface of|the pool table--
{46736}{46796}unless you're a really bad pool player.
{46820}{46867}But whenever the balls collide,
{46868}{46928}there is something that|always seeps off the table,
{47002}{47030}sound waves.
{47031}{47079}That's why I can hear the collision.
{47335}{47383}Now, the idea is that gravity
{47384}{47430}might be like the sound waves,
{47431}{47503}it might not be|confined to our membrane.
{47504}{47551}It might be able to seep off
{47551}{47599}our part of the universe.
{47777}{47839}Or think about it another way.
{47875}{47947}Instead of pool tables,|let's go back to bread.
{47964}{48012}Imagine that our universe is
{48013}{48054}like this slice of toast.
{48055}{48121}And that you and me,|and all of matter--
{48122}{48187}light itself,|everything we see--
{48188}{48230}is like jelly.
{48247}{48307}Now jelly can move freely
{48307}{48355}on the surface of the toast,
{48355}{48402}but otherwise, it's stuck, it can't
{48403}{48451}leave the surface itself.
{48472}{48520}But what if gravity were different?
{48521}{48563}What if gravity were more
{48563}{48610}like cinnamon and sugar?
{48611}{48657}Now, this stuff isn't sticky at all,
{48671}{48714}so it easily slides
{48714}{48760}right off the surface.
{48820}{48862}But why would gravity
{48863}{48904}be so different from everything else
{48904}{48952}that we know of in the universe?
{48957}{49036}Well, turns out that|string theory, or M-theory,
{49037}{49084}provides an answer.
{49149}{49204}It all has to do with shape.
{49240}{49312}For years, we concentrated on strings
{49313}{49384}that were closed loops,|like rubber bands.
{49396}{49436}But after M-theory,
{49436}{49496}we turned our attention to other kinds.
{49527}{49587}Now we think that|everything we see around us,
{49588}{49647}like matter and light,
{49648}{49720}is made of open-ended strings,
{49731}{49791}and the ends of each string
{49791}{49887}are tied down to our|threedimensional membrane.
{49947}{50019}But closed loops of string do exist,
{50048}{50127}and one kind is responsible for gravity.
{50144}{50192}It's called a graviton.
{50264}{50299}With closed loops,
{50300}{50355}there are no loose ends to tie down,
{50369}{50412}so gravitons are free
{50413}{50456}to escape into the other dimensions,
{50463}{50511}diluting the strength of gravity
{50523}{50570}and making it seem weaker
{50571}{50619}than the other forces of nature.
{50655}{50715}This suggests an intriguing possibility.
{50739}{50770}Riddle of the Big Bang
{50775}{50827}If we do live on a membrane
{50827}{50897}and there are parallel|universes on other membranes
{50898}{50962}near us, we may never see them,
{50963}{51026}but perhaps we could one day feel them
{51027}{51074}through gravity.
{51075}{51135}SAVAS DIMOPOULOS: If there|happens to be intelligent life
{51135}{51183}on one of the membranes,
{51184}{51225}then this intelligent life
{51226}{51266}might be very close to us.
{51266}{51326}So theoretically, and|purely theoretically,
{51327}{51373}we might be able to communicate
{51374}{51434}with this intelligent life by
{51435}{51506}exchanging strong gravity wave sources.
{51537}{51577}BRIAN GREENE: So who knows?
{51578}{51638}Maybe someday we'll|develop the technology
{51638}{51686}and use gravity waves to actually
{51687}{51734}communicate with other worlds.
{51914}{51949}ALIEN:|Ay-yoo-ya.
{51950}{52010}BRIAN GREENE: Yes, hey,|it's Brian. How you doing?
{52011}{52070}ALIEN: Brian, hoh-ba|jubby wah-fa-loo
{52071}{52118}poo-jabba "Simpsons!"
{52178}{52250}BRIAN GREENE: We don't really|know if parallel universes
{52251}{52309}could have a real impact on us.
{52310}{52382}But there is one very|controversial idea,
{52382}{52441}which says they've already|played a major role.
{52442}{52526}In fact, it gives them|credit for our existence.
{52598}{52646}As the classic story goes,
{52653}{52717}the vast universe we see today was once
{52718}{52766}extremely small,
{52767}{52813}unimaginably small.
{52837}{52909}Then, suddenly,|it got bigger--
{52991}{53065}a lot bigger-- during the|dramatic event known as
{53070}{53125}the Big Bang.
{53161}{53233}The Big Bang stretched|the fabric of space
{53234}{53281}and set off the chain of events
{53281}{53329}that brought us to the universe
{53330}{53377}we know and love today.
{53401}{53461}But there's always been|a couple of problems
{53462}{53509}with the Big Bang theory.
{53521}{53593}First, when you squeeze the entire
{53594}{53665}universe into an infinitesimally small,
{53666}{53725}but stupendously dense package,
{53741}{53797}at a certain point, our laws of physics
{53797}{53845}simply break down.
{53845}{53904}They just don't make sense anymore.
{53948}{54003}DAVID GROSS: The formulas|we use start giving
{54004}{54049}answers that are nonsensical.
{54061}{54121}We find total disaster.
{54137}{54197}Everything breaks down, and we're stuck.
{54216}{54293}BRIAN GREENE: And on top of|this, there's the bang itself.
{54312}{54355}What exactly is that?
{54408}{54456}ALAN GUTH: That's actually a problem.
{54480}{54528}The classic form of the|Big Bang theory really
{54529}{54561}says nothing about what banged,
{54562}{54593}what happened before it banged,
{54593}{54629}or what caused it to bang.
{54672}{54732}BRIAN GREENE: Refinements|to the Big Bang theory
{54733}{54792}do suggest explanations for the Bang,
{54804}{54864}but none of them turn the clock back
{54865}{54936}completely to the moment|when everything started.
{54958}{55008}PAUL STEINHARDT Most|people come at this with the naive notion
{55009}{55068}that there was a|beginning-- that somehow
{55069}{55128}space and time emerged from nothingness
{55129}{55176}into somethingness.
{55180}{55248}BURT OVRUT: Well, I don't know|about you, but I don't like nothing.
{55293}{55353}Do I really believe that the universe
{55354}{55413}was a Big Bang out of nothing?
{55437}{55503}And I'm not a philosopher,
{55504}{55561}so I won't say. But I could|imagine to a philosopher,
{55561}{55617}that is a problem. But to a physicist,
{55618}{55665}I think, it's also a problem.
{55672}{55761}BRIAN GREENE: Everyone admits|there are problems. The question is:
{55773}{55833}"Can string theory solve them?"
{55866}{55916}Some string theorists have suggested
{55917}{55996}that the Big Bang wasn't|the beginning at all,
{56008}{56073}that the universe could|have existed long before
{56074}{56121}even forever.
{56128}{56193}Not everyone is|comfortable with the idea.
{56212}{56260}ALAN GUTH: I actually|find it rather unattractive
{56261}{56311}to think about a universe|without a beginning.
{56311}{56360}It seems to me that a|universe without a beginning
{56361}{56409}is also a universe|without an explanation.
{56433}{56480}BRIAN GREENE: So what|is the explanation?
{56514}{56569}What if string theory is right,
{56570}{56624}and we are all living|on a giant membrane
{56625}{56685}inside a higher dimensional space?
{56720}{56759}PAUL STEINHARDT: One of the|ideas in string theory that was
{56760}{56818}particularly striking|to me, and suggested
{56819}{56872}perhaps a new direction for cosmology,
{56872}{56947}is the idea of branes and the idea
{56948}{57020}of branes moving in extra dimensions.
{57051}{57111}BRIAN GREENE: Some scientists|have proposed that the answer
{57112}{57158}to the Big Bang riddle
{57159}{57219}lies in the movements|of these giant branes.
{57238}{57284}BURT OVRUT: It's so simple.
{57284}{57332}Here's a brane on which we live,
{57333}{57367}and here's another brane
{57368}{57410}floating in the higher dimension.
{57411}{57456}There's absolutely|nothing difficult about
{57457}{57512}imagining that these|collide with each other.
{57596}{57643}BRIAN GREENE: According to this idea,
{57644}{57692}some time before the Big Bang,
{57697}{57759}two branes carrying parallel universes
{57760}{57824}began drifting toward each other,
{57855}{57903}until...
{57980}{58028}BURT OVRUT: All of that|energy has to go somewhere.
{58040}{58124}Where does it go? It|goes into the Big Bang.
{58136}{58183}It creates the expansion that we see,
{58195}{58267}and it heats up all the|particles in the universe
{58268}{58315}in this big, fiery mass.
{58363}{58411}BRIAN GREENE: As if this|weren't weird enough,
{58418}{58470}the proponents of this idea make
{58471}{58519}another radical claim:
{58543}{58615}the Big Bang was not a special event.
{58627}{58680}They say that parallel universes
{58680}{58752}could have collided, not|just once in the past,
{58790}{58867}but again|and again--
{58958}{59023}and that it will happen in the future.
{59044}{59106}If this view is right, there's
{59106}{59166}a brane out there right now,
{59167}{59251}headed on a collision|course with our universe.
{59279}{59323}PAUL STEINHARDT: So|another collision is coming,
{59323}{59371}and there'll be another Big Bang.
{59372}{59418}And this will just repeat itself for
{59418}{59466}an indefinite period into the future.
{59491}{59539}BRIAN GREENE: It's an intriguing idea.
{59551}{59593}Unfortunately,
{59594}{59642}there are a few technical problems.
{59706}{59772}DAVID GROSS: Well, that was|a very ingenious scenario
{59773}{59838}that arose naturally|within string theory.
{59850}{59898}However, the good old problems
{59899}{59946}creep back in again.
{59958}{60006}BRIAN GREENE: The fact|is we don't really know
{60007}{60054}what happens when two branes collide.
{60078}{60131}You can wind up with the same situation
{60131}{60179}we had with the Big Bang;
{60186}{60246}the equations don't make sense.
{60270}{60318}GARY HOROWITZ: They have|to make a lot of assumptions
{60319}{60366}in their models, and|I don't think they've
{60367}{60414}really solved the|problem of the Big Bang
{60415}{60462}in string theory.
{60503}{60546}BRIAN GREENE: If string theory is the
{60547}{60594}one true theory of the universe,
{60606}{60666}it will have to solve the|riddle of the Big Bang.
{60673}{60718}And there's a lot of hope that someday
{60719}{60761}string theory will succeed.
{60762}{60824}But for now, there's|also a lot of uncertainty.
{60834}{60906}As promising and exciting the theory is,
{60918}{60978}we don't entirely understand it.
{61006}{61042}DAVID GROSS: It's as if we've stumbled
{61042}{61077}in the dark into a house,
{61078}{61126}which we thought was|a two bedroom apartment
{61127}{61172}and now we're discovering is
{61173}{61217}a nineteen-room|mansion-- at least.
{61218}{61258}And maybe it's got a thousand rooms,
{61258}{61302}and we're just beginning our journey.
{61309}{61361}BRIAN GREENE: So how sure are we that
{61361}{61433}the universe is the way that|string theory describes it?
{61443}{61493}Is the world really made up
{61494}{61540}of strings and membranes,
{61541}{61613}parallel universes and extra dimensions?
{61620}{61697}Is this all science or science fiction?
{61698}{61732}Signs of Strings
{61733}{61781}MICHAEL DUFF: Well, the|question we often ask
{61782}{61829}ourselves as we work|through our equations is,
{61839}{61894}"Is this just fancy mathematics,
{61895}{61947}or is it describing the real world?"
{61964}{62067}S. JAMES GATES, JR.: These exercises|in our imagination of mathematics
{62074}{62142}are all, at the end of the day,
{62143}{62210}subjected to a single question:
{62222}{62274}"Is it there in the laboratory?
{62275}{62326}Can you find its evidence?"
{62335}{62378}JOSEPH LYKKEN: String|theory and string theorists
{62379}{62413}do have a real problem.
{62414}{62462}How do you actually test string theory?
{62462}{62505}If you can't test it in the way
{62506}{62551}that we test normal theories,
{62552}{62605}it's not science, it's philosophy,
{62606}{62654}and that's a real problem.
{62666}{62714}BRIAN GREENE: Strings|are thought to be so tiny,
{62726}{62774}much smaller than an atom,
{62775}{62822}that there's probably no way
{62823}{62858}to see them directly.
{62906}{62966}But even if we never see strings,
{62967}{63026}we may someday see their fingerprints.
{63026}{63074}You see, if strings were around
{63075}{63121}at the beginning of the universe,
{63122}{63170}when things were really tiny,
{63177}{63266}they would have left impressions|or traces on their surroundings.
{63278}{63326}And then, after the Big Bang,
{63327}{63373}when everything expanded,
{63374}{63422}those traces would|have been stretched out
{63423}{63470}along with everything else.
{63477}{63542}So, if that's true, we may someday see
{63542}{63602}the tell-tale signs of strings
{63602}{63650}somewhere in the stars.
{63746}{63788}But even here on earth
{63788}{63827}there's a chance we can detect
{63828}{63866}evidence of strings.
{63899}{63973}This pasture in Illinois|serves as command central
{63974}{64021}for a lot of this research.
{64065}{64133}Well, actually, the real work happens
{64134}{64200}underground where the hunt is on for
{64201}{64249}evidence supporting string theory,
{64256}{64309}including extra dimensions.
{64369}{64417}JOSEPH LYKKEN: Not too many|years ago, people who talked
{64418}{64466}about large extra dimensions
{64466}{64513}would have been considered crackpots,
{64514}{64549}to put it lightly.
{64573}{64615}BRIAN GREENE: But all that has changed,
{64616}{64669}thanks to string theory.
{64765}{64812}This is Fermilab,
{64813}{64872}and right now, it's our best hope for
{64873}{64933}proving that extra dimensions are real.
{65017}{65101}Fermilab has a giant atom smasher.
{65101}{65149}Here's how it works:
{65173}{65233}scientists zap hydrogen atoms with
{65233}{65281}huge amounts of electricity.
{65293}{65347}Later, they strip them of their
{65347}{65400}electrons and send the protons
{65401}{65448}zooming around a four mile
{65448}{65496}circular tunnel beneath the prairie.
{65597}{65661}Just as they're approaching|the speed of light,
{65661}{65724}they are steered into|collisions with particles
{65725}{65784}whizzing in the opposite direction.
{65945}{66014}Most collisions are just glancing blows,
{66015}{66084}but occasionally there's a direct hit.
{66149}{66196}The result is a shower
{66197}{66257}of unusual subatomic particles.
{66288}{66342}The hope is that among these particles
{66343}{66396}will be a tiny unit of gravity,
{66415}{66463}the graviton.
{66468}{66534}Gravitons, according|to string theory, are
{66534}{66603}closed loops, so they can float off
{66604}{66671}into the extra dimensions.
{66681}{66756}The grand prize would be|a snapshot of a graviton
{66756}{66804}at the moment of escape.
{66828}{66893}MARIA SPIROPULU And then|the graviton goes to the extra dimension,
{66894}{66959}and then it shows in the|detector by its absence.
{66960}{67019}You see it by its absence.
{67055}{67109}BRIAN GREENE: Unfortunately,|Fermilab hasn't
{67110}{67163}yet "seen" the vanishing graviton.
{67211}{67271}And the pressure is|on, because another team
{67272}{67331}is hot on the same trail.
{67506}{67559}Four thousand miles away,
{67559}{67607}on the border of France and Switzerland,
{67617}{67679}a lab called CERN is constructing
{67680}{67727}an enormous new atom smasher.
{67883}{67950}When it's finished,|it will be seven times
{67951}{68010}more powerful than Fermilab's.
{68046}{68098}JOSEPH LYKKEN: There's|a great sense of urgency
{68098}{68158}that every minute has|to count, but eventually,
{68159}{68207}CERN, our rival laboratory,
{68208}{68254}will frankly blow us out of the water.
{68300}{68362}BRIAN GREENE: CERN will blow|Fermilab out of the water,
{68362}{68422}not only in the search|for extra dimensions,
{68423}{68470}but other wild ideas.
{68518}{68558}At the top of the "to do" list
{68559}{68605}for both labs is the hunt for something
{68605}{68650}called "supersymmetry,"
{68657}{68722}that's a central|prediction of string theory.
{68727}{68782}And it says, in a|nutshell, that for every
{68783}{68836}subatomic particle we're familiar with,
{68837}{68921}like electrons, photons, and gravitons,
{68922}{68957}there should also be a much
{68957}{69004}heavier partner
{69005}{69053}called a "sparticle," which
{69054}{69101}so far no one has ever seen.
{69108}{69150}Now, because string|theory says sparticles
{69151}{69192}should exist,
{69193}{69240}finding them is a major priority.
{69259}{69331}MARIA SPIROPULU: So, it's a big|discovery to find supersymmetry.
{69332}{69390}That's, that's a|humongous discovery and,
{69391}{69438}and I think it's a|bigger discovery to find
{69439}{69487}supersymmetry than to find life on Mars.
{69487}{69582}AMANDA PEET: If we were to hear tomorrow
{69583}{69655}that supersymmetry was|discovered, there would
{69656}{69715}be parties all over the planet.
{69722}{69780}BRIAN GREENE: The|problem is, if they exist,
{69785}{69834}the sparticles of supersymmetry
{69835}{69883}are probably incredibly heavy,
{69895}{69949}so heavy that they may not be detected
{69950}{70003}with today's atom smashers.
{70015}{70058}The new facility at CERN will
{70059}{70099}have the best chance, once
{70099}{70171}it's up and running in several years,
{70172}{70218}but that won't stop the folks at
{70219}{70279}Fermilab from trying to find them first.
{70303}{70351}MARIA SPIROPULU: The competition is
{70352}{70398}friendly and fierce at the same time.
{70399}{70447}We're competing like bad dogs,
{70448}{70482}essentially.
{70483}{70543}It has always been like that,|and it will always be like that.
{70555}{70615}JOSEPH LYKKEN: We have to make sure|that we don't make any mistakes, that
{70615}{70662}we do absolutely the|best we can do at these
{70663}{70722}experiments and take advantage|of what is really one of
{70723}{70783}the great golden|opportunities for discovery.
{70792}{70835}BRIAN GREENE: If we do find sparticles,
{70836}{70881}it won't prove string theory,
{70882}{70926}but it will be really strong
{70927}{70969}circumstantial evidence that we're
{70970}{71010}on the right track.
{71010}{71046}Too Elegant to be Wrong?
{71047}{71117}Over the next 10 to 20 years, the new
{71118}{71178}generation of atom smashers is sure
{71178}{71226}to uncover surprising truths
{71226}{71274}about the nature of our universe.
{71286}{71340}But will it be the universe
{71341}{71393}predicted by string theory?
{71394}{71442}What if we don't find sparticles?
{71443}{71490}Or extra dimensions?
{71538}{71598}What if we never find any evidence that
{71599}{71650}supports this weird new universe
{71651}{71754}filled with membranes and|tiny vibrating strings?
{71790}{71835}Could string theory, in the end,
{71836}{71885}be wrong?
{71886}{71941}MICHAEL DUFF: Oh yes, it's|certainly a logical possibility
{71946}{71989}that we've all been wasting our time
{71990}{72024}for the last twenty years
{72025}{72057}and that the theory is
{72058}{72089}completely wrong.
{72090}{72132}JOSEPH LYKKEN: There have|been periods of many years
{72133}{72174}where all of the smart people,
{72174}{72204}all of the cool people,
{72205}{72236}were working on one kind of theory,
{72236}{72269}moving in one kind of direction,
{72270}{72318}and even though they|thought it was wonderful,
{72319}{72353}it turned out to be a dead end.
{72354}{72402}This could happen to string theory.
{72438}{72497}BRIAN GREENE: Even though|there's no real evidence yet,
{72498}{72570}so much of string theory|just makes so much sense;
{72605}{72653}a lot of us believe
{72653}{72701}it's just got to be right.
{72730}{72785}STEVEN WEINBERG: I don't think|it's ever happened that a theory
{72786}{72850}that has the kind of mathematical appeal
{72901}{72941}that string theory has
{72941}{73013}turned out to be entirely wrong.
{73014}{73084}I would find it hard to|believe that that much elegance
{73085}{73181}and mathematical beauty|would simply be wasted.
{73217}{73289}GARY HOROWITZ: I don't really|know how close we are to the end.
{73301}{73373}You know, are we almost there|in having the complete story?
{73374}{73433}Is it going to still|be another ten years?
{73434}{73480}Nobody knows.
{73481}{73535}But I think it's going to keep
{73536}{73589}me busy for a long time.
{73589}{73625}JOSEPH LYKKEN: We have|been incredibly lucky.
{73626}{73666}Nature has somehow allowed us
{73667}{73712}to unlock the keys
{73713}{73757}to many fundamental mysteries already.
{73758}{73799}How far can we push that?
{73800}{73860}We won't know until we, until we try.
{73889}{73940}BRIAN GREENE: A century|ago, some scientists
{73941}{73991}thought they had pretty much figured out
{73992}{74040}the basic laws of the universe.
{74068}{74164}But then Einstein came along|and dramatically revised
{74165}{74237}our views of space and time and gravity.
{74330}{74372}And quantum mechanics unveiled
{74373}{74433}the inner workings of|atoms and molecules,
{74452}{74512}revealing a world that's|bizarre and uncertain.
{74555}{74606}So, far from confirming
{74607}{74655}that we had sorted it all out,
{74656}{74728}the 20th century showed|that every time we looked
{74729}{74800}more closely at the|universe, we discovered
{74801}{74896}yet another unexpected layer of reality.
{74944}{75004}As we embark on the 21st century,
{75014}{75098}we're getting a glimpse of|what may be the next layer:
{75098}{75181}vibrating strings, sparticles,
{75193}{75265}parallel universes and extra dimensions.
{75277}{75337}It's a breathtaking vision, and
{75338}{75398}in a few years, experiments|may begin to tell us
{75398}{75457}whether some of these ideas are right
{75458}{75503}or wrong.
{75510}{75589}But, regardless of the|outcome, we'll keep going,
{75590}{75649}because, well, that's what we do.
{75650}{75692}We follow our curiosity.
{75692}{75743}We explore the unknown.
{75744}{75790}And a hundred or a|thousand years from now,
{75791}{75835}today's view of the cosmos
{75836}{75889}may look woefully incomplete,
{75890}{75937}perhaps even quaint.
{75980}{76036}But undeniably, the ideas we
{76037}{76093}call string theory are a testament
{76094}{76153}to the power of human creativity.
{76157}{76212}They've opened a whole new spectrum
{76213}{76285}of possible answers|to age-old questions.
{76285}{76345}And with them, we've taken a dramatic
{76345}{76405}leap in our quest to fully understand
{76417}{76453}this elegant universe.
{76501}{76568}Made by: Nauris Eðenvalds|Coool Coool Corp. ©