TED2005
Brian Greene: Making sense of string theory
Brian Greene o teoriji struna
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Fizičar Brian Greene objašnjava teoriju superstruna, po kojoj tanke niti vibrirajući u 11 dimenzija, stvaraju sve čestice i sile u svemiru.
Brian Greene - Physicist
Brian Greene is perhaps the best-known proponent of superstring theory, the idea that minuscule strands of energy vibrating in a higher dimensional space-time create every particle and force in the universe. Full bio
Brian Greene is perhaps the best-known proponent of superstring theory, the idea that minuscule strands of energy vibrating in a higher dimensional space-time create every particle and force in the universe. Full bio
Double-click the English transcript below to play the video.
00:13
In the year 1919,
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Godine 1919.
00:15
a virtually unknown German mathematician, named Theodor Kaluza
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praktički nepoznat njemački matematičar po imenu Theodor Kaluza
00:22
suggested a very bold and, in some ways, a very bizarre idea.
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iznio je vrlo odvažnu i, na neki način, bizarnu ideju.
00:29
He proposed that our universe
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Rekao je da bi naš svemir
00:31
might actually have more than the three dimensions
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mogao imati više od tri dimenzije
00:34
that we are all aware of.
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koje svi poznajemo.
00:37
That is in addition to left, right, back, forth and up, down,
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Pored lijevo, desno, naprijed, nazad i gore, dolje,
00:40
Kaluza proposed that there might be additional dimensions of space
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Kaluza je predložio da bi mogle postojati dodatne prostorne dimenzije
00:45
that for some reason we don't yet see.
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koje iz nekog razloga još ne vidimo.
00:48
Now, when someone makes a bold and bizarre idea,
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Naime, kada netko iznese odvažnu i bizarnu ideju,
00:52
sometimes that's all it is -- bold and bizarre,
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ona je nekad samo to -- odvažna i bizarna,
00:54
but it has nothing to do with the world around us.
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ali nema nikakve veze sa svijetom oko nas.
00:57
This particular idea, however --
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Međutim, ova ideja --
00:59
although we don't yet know whether it's right or wrong,
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iako još ne znamo je li valjana ili ne,
01:02
and at the end I'll discuss experiments which, in the next few years,
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a na kraju ću razmotriti pokuse koji bi nam u sljedećih nekoliko godina,
01:05
may tell us whether it's right or wrong --
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mogli reći je li valjana ili ne --
01:07
this idea has had a major impact on physics in the last century
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ova ideja imala je veliki utjecaj na fizičare u prošlom stoljeću
01:11
and continues to inform a lot of cutting-edge research.
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i nadalje nadahnjuje mnoga najnaprednija istraživanja.
01:14
So, I'd like to tell you something about the story of these extra dimensions.
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Stoga bih vam htio ispričati nešto o ovim dodatnim dimenzijama.
01:18
So where do we go?
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Dakle, kamo idemo?
01:20
To begin we need a little bit of back story. Go to 1907.
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Za početak trebamo malo pozadine. Idemo u 1907.
01:23
This is a year when Einstein is basking in the glow
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To je godina kad Einstein uživa slavu
01:27
of having discovered the special theory of relativity
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otkrivši specijalnu teoriju relativnosti
01:30
and decides to take on a new project,
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i odlučuje prihvatiti se novog zadatka: --
01:33
to try to understand fully the grand, pervasive force of gravity.
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potpuno shvatiti gravitaciju, tu veliku silu koja prožima sve.
01:40
And in that moment, there are many people around
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U to doba mnogi ljudi misle
01:43
who thought that that project had already been resolved.
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da je taj zadatak već riješen.
01:47
Newton had given the world a theory of gravity in the late 1600s
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Newton je podario svijetu teoriju gravitacije krajem 17. stoljeća
01:50
that works well, describes the motion of planets,
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koja dobro funkcionira, objašnjava gibanje planeta,
01:54
the motion of the moon and so forth,
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gibanje mjeseca,
01:56
the motion of apocryphal of apples falling from trees,
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gibanje jabuka koje padaju sa stabala,
01:59
hitting people on the head.
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udarajući ljude po glavi.
02:01
All of that could be described using Newton's work.
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Sve to se može opisati pomoću Newtonova djela.
02:03
But Einstein realized that Newton had left something out of the story,
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Ali Einstein je shvatio da je Newton izostavio nešto iz cijele priče,
02:07
because even Newton had written
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jer je čak i Newton napisao
02:10
that although he understood how to calculate the effect of gravity,
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da iako je shvatio kako izračunati utjecaj gravitacije,
02:15
he'd been unable to figure out how it really works.
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nije uspio shvatiti kako ona ustvari funkcionira.
02:18
How is it that the Sun, 93 million miles away,
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Kako to da Sunce, udaljeno 150 milijuna km,
02:21
[that] somehow it affects the motion of the Earth?
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nekako utječe na gibanje zemlje?
02:24
How does the Sun reach out across empty inert space and exert influence?
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Kako Sunce prodire kroz prazan i trom prostor i vrši utjecaj?
02:28
And that is a task to which Einstein set himself --
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I to je zadatak koji si je Einstein zadao --
02:31
to figure out how gravity works.
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shvatiti kako funkcionira gravitacija.
02:34
And let me show you what it is that he found.
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Dopustite da vam pokažem što je otkrio.
02:37
So Einstein found
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Einstein je otkrio
02:38
that the medium that transmits gravity is space itself.
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da je sâm prostor medij koji prenosi gravitaciju.
02:42
The idea goes like this:
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Ideja je sljedeća:
02:44
imagine space is a substrate of all there is.
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zamislite da je prostor podloga svega što postoji.
02:46
Einstein said space is nice and flat, if there's no matter present.
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Einstein kaže da je prostor ravan ako na njemu nema nikakve materije.
02:50
But if there is matter in the environment, such as the Sun,
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Ali ako postoji materija u prostoru, kao što je Sunce,
02:54
it causes the fabric of space to warp, to curve.
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ona uzrokuje zakrivljenost prostora.
02:58
And that communicates the force of gravity.
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I to prenosi silu gravitacije.
03:00
Even the Earth warps space around it.
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Čak i Zemlja zakrivljuje prostor oko sebe.
03:03
Now look at the Moon.
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Sad pogledajte Mjesec.
03:05
The Moon is kept in orbit, according to these ideas,
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Prema ovoj teoriji, Mjesec ostaje u orbiti
03:08
because it rolls along a valley in the curved environment
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jer se kotrlja po udolini u zakrivljenom prostoru
03:11
that the Sun and the Moon and the Earth can all create by virtue of their presence.
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koju Sunce, Mjesec i Zemlja mogu stvoriti svojom prisutnošću.
03:16
We go to a full-frame view of this.
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Sad pogledajmo cijelu sliku.
03:19
The Earth itself is kept in orbit
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Sama Zemlja ostaje u orbiti
03:21
because it rolls along a valley in the environment that's curved
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jer se kotrlja po udolini u prostoru koji je zakrivljen
03:25
because of the Sun's presence.
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zbog Sunčeve prisutnosti.
03:27
That is this new idea about how gravity actually works.
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To je nova ideja kako ustvari djeluje gravitacija.
03:32
Now, this idea was tested in 1919 through astronomical observations.
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Naime, ova ideja je testirana 1919. astronomskim opažanjima.
03:37
It really works. It describes the data.
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Zaista djeluje. Opisuje opažanja.
03:40
And this gained Einstein prominence around the world.
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I time je Einstein stekao ugled diljem svijeta.
03:44
And that is what got Kaluza thinking.
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I to je navelo Kaluzu na razmišljanje.
03:48
He, like Einstein, was in search of what we call a unified theory.
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On je, kao i Einstein, bio u potrazi za tzv. "objedinjenom teorijom".
03:52
That's one theory
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Radi se o teoriji
03:54
that might be able to describe all of nature's forces from one set of ideas,
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koja bi sama mogla opisati sve prirodne sile pomoću jednog skupa ideja,
03:58
one set of principles, one master equation, if you will.
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jednog skupa principa, takoreći jedne glavne formule.
04:02
So Kaluza said to himself,
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Stoga je Kaluza zaključio,
04:04
Einstein has been able to describe gravity
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Einstein je uspio opisati gravitaciju
04:07
in terms of warps and curves in space --
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u odnosu na uvijanje i zakrivljenje prostora --
04:09
in fact, space and time, to be more precise.
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točnije, prostora i vremena.
04:12
Maybe I can play the same game with the other known force,
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Možda ja mogu napraviti isto s drugom poznatom silom,
04:17
which was, at that time, known as the electromagnetic force --
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koja je u to vrijeme bila poznata kao elektromagnetska sila.
04:20
we know of others today, but at that time
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Danas znamo i za druge, ali u ono doba
04:22
that was the only other one people were thinking about.
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to je bila jedina druga o kojoj su ljudi razmišljali.
04:24
You know, the force responsible for electricity
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Znate, sila odgovorna za struju,
04:26
and magnetic attraction and so forth.
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magnetsku privlačnost i slično.
04:28
So Kaluza says, maybe I can play the same game
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I tako Kaluza kaže, možda i ja mogu napraviti isto
04:31
and describe electromagnetic force in terms of warps and curves.
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i objasniti elektromagnetsku silu pomoću uvijanja i zakrivljenosti.
04:35
That raised a question: warps and curves in what?
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To je postavilo pitanje uvijanje i krivljenje čega?
04:38
Einstein had already used up space and time,
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Einstein je već iskoristio prostor i vrijeme,
04:43
warps and curves, to describe gravity.
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uvijanje i krivljenje, da opiše gravitaciju.
04:45
There didn't seem to be anything else to warp or curve.
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Kao da nije ništa više ostalo za uvijanje i krivljenje.
04:48
So Kaluza said, well, maybe there are more dimensions of space.
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I tako Kaluza kaže, možda postoji više dimenzija prostora.
04:53
He said, if I want to describe one more force,
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Rekao je, ako želim opisati još jednu silu,
04:55
maybe I need one more dimension.
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možda mi treba još jedna dimenzija.
04:57
So he imagined that the world had four dimensions of space, not three,
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Zamislio je da svijet ima četiri prostorne dimenzija, a ne tri,
05:01
and imagined that electromagnetism was warps and curves
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i da je elektromagnetizam uvijanje i krivljenje
05:05
in that fourth dimension. Now here's the thing:
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u toj četvrtoj dimenziji. Pazite sad ovo:
05:07
when he wrote down the equations describing warps and curves
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kad je napisao formulu koja opisuje uvijanje i krivljenje
05:10
in a universe with four space dimensions, not three,
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u svemiru s četiri prostorne dimenzije, a ne tri,
05:13
he found the old equations that Einstein had already derived in three dimensions --
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dobio je stare formule koje je Einstein već izveo u tri dimenzije --
05:17
those were for gravity --
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za gravitaciju --
05:18
but he found one more equation because of the one more dimension.
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ali je dobio još jednu formulu zbog dodatne dimenzije.
05:22
And when he looked at that equation,
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I kad je pogledao tu formulu,
05:24
it was none other than the equation
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to nije bila ništa drugo nego formula
05:26
that scientists had long known to describe the electromagnetic force.
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za koju su znanstvenici već dugo znali da opisuje elektromagnetsku silu.
05:29
Amazing -- it just popped out.
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Zadivljujuće -- samo se pojavila.
05:31
He was so excited by this realization
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Bio je toliko uzbuđen svojim otkrićem
05:34
that he ran around his house screaming, "Victory!" --
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da je trčao oko kuće vičući "Pobjeda!" --
05:37
that he had found the unified theory.
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što je otkrio objedinjenu teoriju.
05:40
Now clearly, Kaluza was a man who took theory very seriously.
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Naravno, Kaluza je bio čovjek koji vrlo ozbiljno shvaća teoriju.
05:47
He, in fact --
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On, zapravo --
05:48
there is a story that when he wanted to learn how to swim,
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postoji priča da je, kad je htio naučiti plivati,
05:51
he read a book, a treatise on swimming --
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pročitao knjigu, raspravu o plivanju --
05:54
(Laughter)
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(Smijeh)
05:55
-- then dove into the ocean.
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-- i zatim zaronio u ocean.
05:57
This is a man who would risk his life on theory.
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On je čovjek koji bi riskirao svoj život prema teoriji.
06:00
Now, but for those of us who are a little bit more practically minded,
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Ali za one među nama koji su više praktičnog uma,
06:04
two questions immediately arise from his observation.
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iz ovih promatranja odmah proizlaze dva pitanja.
06:07
Number one: if there are more dimensions in space, where are they?
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Prvo: ako je više dimenzija u prostoru, gdje su?
06:11
We don't seem to see them.
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Izgleda da ih ne vidimo.
06:13
And number two: does this theory really work in detail,
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I drugo: djeluje li ova teorija doista precizno,
06:17
when you try to apply it to the world around us?
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kad ju primijenimo na svijet oko nas?
06:20
Now, the first question was answered in 1926
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Na prvo pitanje odgovor je dao 1926.
06:24
by a fellow named Oskar Klein.
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mladić zvan Oskar Klein.
06:26
He suggested that dimensions might come in two varieties --
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On je iznio ideju da se dimenzije mogu pojavljivati u dvije varijante --
06:30
there might be big, easy-to-see dimensions,
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dimenzije mogu biti velike, lako vidljive,
06:33
but there might also be tiny, curled-up dimensions,
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ali mogu biti i male, uvijene,
06:36
curled up so small, even though they're all around us,
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uvijene tako sitno da ih, iako su svuda oko nas,
06:39
that we don't see them.
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ne možemo vidjeti.
06:41
Let me show you that one visually.
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Dopustite da vam to prikažem vizualno.
06:43
So, imagine you're looking at something
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Zamislite da gledate u nešto
06:45
like a cable supporting a traffic light.
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kao kabel koji drži semafor.
06:47
It's in Manhattan. You're in Central Park -- it's kind of irrelevant --
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Nalazi se u Manhattanu. Vi ste u Central Parku -- nebitno je --
06:50
but the cable looks one-dimensional from a distant viewpoint,
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ali kabel izdaleka izgleda jednodimenzionalno,
06:54
but you and I all know that it does have some thickness.
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ali i vi i ja znamo da ima određenu debljinu.
06:57
It's very hard to see it, though, from far away.
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Koju je, doduše, teško vidjeti izdaleka.
06:59
But if we zoom in and take the perspective of, say,
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Ali ako se približimo i pogledamo iz perspektive, recimo,
07:01
a little ant walking around --
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malog mrava koji hoda okolo --
07:03
little ants are so small that they can access all of the dimensions --
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mravi su tako mali da mogu pristupiti svim dimenzijama ---
07:06
the long dimension,
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dimenziji dužine,
07:08
but also this clockwise, counter-clockwise direction.
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ali također i smjeru kazaljke na satu i obrnuto.
07:11
And I hope you appreciate this.
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Nadam se da cijenite ovo.
07:13
It took so long to get these ants to do this.
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Dugo nam je trebalo da nagovorimo mrave da ovo izvedu.
07:15
(Laughter)
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(Smijeh)
07:16
But this illustrates the fact that dimensions can be of two sorts:
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Ali to ilustrira činjenicu da postoje dvije vrste dimenzija:
07:19
big and small. And the idea that maybe the big dimensions around us
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velike i male. I ideju da su možda velike dimenzije oko nas
07:23
are the ones that we can easily see,
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one koje lako možemo vidjeti,
07:25
but there might be additional dimensions curled up,
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ali da također postaje dodatne, uvrnute dimenzije,
07:28
sort of like the circular part of that cable,
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poput kružnog dijela kabela,
07:30
so small that they have so far remained invisible.
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tako sitne da su do sada bile nevidljive.
07:34
Let me show you what that would look like.
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Dopustite da vam pokažem kako bi to izgledalo.
07:36
So, if we take a look, say, at space itself --
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Ako pogledamo, recimo, prostore --
07:39
I can only show, of course, two dimensions on a screen.
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na ekranu mogu, naravno, prikazati samo dvije dimenzije.
07:43
Some of you guys will fix that one day,
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Neki od vas ovdje će riješiti taj problem jednog dana,
07:45
but anything that's not flat on a screen is a new dimension,
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ali sve što na ekranu nije ravno je nova dimenzija,
07:47
goes smaller, smaller, smaller,
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postaje sve manja, i manja, i manja
07:49
and way down in the microscopic depths of space itself,
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i u mikroskopskoj dubini samog prostora --
07:53
this is the idea,
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ovo je ideja:
07:54
you could have additional curled up dimensions --
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nalaze se dodatne, uvinute dimenzije.
07:56
here is a little shape of a circle -- so small that we don't see them.
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Evo jedne u obliku malog kruga -- tako je malen da ga ne možemo vidjeti.
07:59
But if you were a little ultra microscopic ant walking around,
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Ali da ste mikroskopski mrav koji hoda naokolo,
08:03
you could walk in the big dimensions that we all know about --
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mogli biste hodati u velikim dimenzijama koje svi znamo --
08:05
that's like the grid part --
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to je nešto kao rešetkasti dio --
08:07
but you could also access the tiny curled-up dimension
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ali mogli biste pristupiti i maloj, uvinutoj dimenziji
08:10
that's so small that we can't see it with the naked eye
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koja je toliko sitna da je ne možemo vidjeti golim okom,
08:12
or even with any of our most refined equipment.
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pa čak ni našom najrazvijenijom opremom.
08:15
But deeply tucked into the fabric of space itself,
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Ali duboko u građi samog svemira,
08:18
the idea is there could be more dimensions, as we see there.
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kao što smo vidjeli, ideja kaže da bi moglo postojati još dimenzija.
08:22
Now that's an explanation
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Dakle, to je objašnjenje
08:26
about how the universe could have more dimensions than the ones that we see.
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kako svemir može imati više dimenzija nego što ih vidimo.
08:30
But what about the second question that I asked:
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Ali što je s drugim pitanjem koje sam postavio:
08:33
does the theory actually work
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djeluje li teorija
08:35
when you try to apply it to the real world?
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kad se primijeni na stvarni svijet?
08:37
Well, it turns out that Einstein and Kaluza and many others
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Pa, pokazalo se da su Einstein i Kaluza i mnogi drugi
08:40
worked on trying to refine this framework
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pokušavali usavršiti ovaj idejni okvir
08:45
and apply it to the physics of the universe
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i primijeniti ga na fiziku svemira
08:48
as was understood at the time, and, in detail, it didn't work.
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kako je bila shvaćena u to doba, ali to nije funkcioniralo u detaljima.
08:52
In detail, for instance,
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Na primjer, na razini detalja
08:53
they couldn't get the mass of the electron
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nisu uspjeli postići da masa elektrona
08:55
to work out correctly in this theory.
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točno funkcionira u ovoj teoriji.
08:57
So many people worked on it, but by the '40s, certainly by the '50s,
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Mnogo ljudi je radilo na tome, ali do 40-ih, a svakako 50-ih godina
09:02
this strange but very compelling idea
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ova čudna, ali vrlo privlačna ideja --
09:06
of how to unify the laws of physics had gone away.
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kako ujediniti zakone fizike -- je nestala.
09:09
Until something wonderful happened in our age.
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Dok se nije desilo nešto čudesno u naše doba.
09:13
In our era, a new approach to unify the laws of physics
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U našoj eri, novi pristup unificiranju zakona fizike
09:17
is being pursued by physicists such as myself,
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razvijaju fizičari poput mene,
09:19
many others around the world,
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i mnogi drugi diljem svijeta.
09:21
it's called superstring theory, as you were indicating.
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Zove se teorija superstruna, kao što se dalo naslutiti.
09:24
And the wonderful thing is that superstring theory
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I ono što je predivno je da teorija superstruna
09:28
has nothing to do at first sight with this idea of extra dimensions,
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na prvi pogleda nema nikakve veze s idejom o više dimenzija,
09:32
but when we study superstring theory,
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ali kad proučavamo teoriju superstruna,
09:35
we find that it resurrects the idea in a sparkling, new form.
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otkrivamo da oživljuje tu ideju u blistavom novom ruhu.
09:38
So, let me just tell you how that goes.
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Stoga mi dopustite da vam kažem kako glasi.
09:40
Superstring theory -- what is it?
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Teorija superstruna -- što je to?
09:42
Well, it's a theory that tries to answer the question:
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To je teorija koja pokušava odgovoriti na pitanje:
09:44
what are the basic, fundamental, indivisible, uncuttable constituents
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što su osnovni, nedjeljivi, sastojci
09:49
making up everything in the world around us?
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koji sačinjavaju sve na svijetu oko nas?
09:53
The idea is like this.
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Ideja je sljedeća.
09:55
So, imagine we look at a familiar object, just a candle in a holder,
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Zamislite da gledamo poznati predmet, svijeću u svijećnjaku,
10:00
and imagine that we want to figure out what it is made of.
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i zamislite da želimo otkriti od čega se sastoji.
10:03
So we go on a journey deep inside the object and examine the constituents.
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Stoga krenemo na putovanje duboko u taj predmet i proučimo njegov sastav.
10:07
So deep inside -- we all know, you go sufficiently far down, you have atoms.
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Svi znamo da, ako odemo dovoljno duboko, nalazimo atome.
10:11
We also all know that atoms are not the end of the story.
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Znamo i to da atomi nisu kraj priče.
10:14
They have little electrons that swarm around a central nucleus
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Imaju male elektrone koji kruže oko centralne jezgre
10:18
with neutrons and protons.
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sastavljene od neutrona i protona.
10:19
Even the neutrons and protons have smaller particles inside of them known as quarks.
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Čak i neutroni i protoni imaju u sebi sitnije čestice, kvarkove.
10:24
That is where conventional ideas stop.
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I tu tradicionalne ideje završavaju.
10:27
Here is the new idea of string theory.
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Evo nove ideje o teoriji struna.
10:29
Deep inside any of these particles, there is something else.
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U dubini tih čestica, postoji još nešto.
10:34
This something else is this dancing filament of energy.
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To nešto je žareća nit energije.
10:37
It looks like a vibrating string --
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Izgleda kao vibrirajuća struna --
10:39
that's where the idea, string theory comes from.
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odatle ideja o teoriji struna.
10:41
And just like the vibrating strings that you just saw in a cello
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I kao što vibrirajuće strune, koje ste upravo vidjeli kod čela,
10:44
can vibrate in different patterns,
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mogu vibrirati na različite načine,
10:46
these can also vibrate in different patterns.
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tako i ove mogu vibrirati po različitim uzorcima.
10:48
They don't produce different musical notes.
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One ne proizvode različite muzičke note,
10:50
Rather, they produce the different particles making up the world around us.
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već različite čestice koje sačinjavaju svijet oko nas.
10:54
So if these ideas are correct,
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Stoga, ako su ove ideje točne,
10:55
this is what the ultra-microscopic landscape of the universe looks like.
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ovako izgleda ultra mikroskopski krajolik svemira.
11:00
It's built up of a huge number
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Sastoji se od velikog broja
11:02
of these little tiny filaments of vibrating energy,
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malih, sitnih niti vibrirajuće energije,
11:06
vibrating in different frequencies.
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koje vibriraju na različitim frekvencijama.
11:08
The different frequencies produce the different particles.
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Različite frekvencije stvaraju različite čestice.
11:11
The different particles are responsible
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Različite čestice su odgovorne
11:14
for all the richness in the world around us.
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za svo bogatstvo na svijetu oko nas.
11:17
And there you see unification,
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I tu se vidi objedinjenost,
11:19
because matter particles, electrons and quarks,
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jer čestice materije, elektroni i kvarkovi,
11:22
radiation particles, photons, gravitons, are all built up from one entity.
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radijacijske čestice, fotoni, gravitoni, svi su građeni od jednog jedinog entiteta.
11:28
So matter and the forces of nature all are put together
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Stoga su sva materija i sve prirodne sile svrstane zajedno
11:32
under the rubric of vibrating strings.
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u skupinu vibrirajućih struna.
11:34
And that's what we mean by a unified theory.
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I to smatramo objedinjenom teorijom.
11:38
Now here is the catch.
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Međutim, postoji kvaka.
11:40
When you study the mathematics of string theory,
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Kad se proučava matematika teorije struna,
11:43
you find that it doesn't work
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pokazuje se da ne funkcionira
11:45
in a universe that just has three dimensions of space.
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u svemiru koji ima samo tri prostorne dimenzije.
11:48
It doesn't work in a universe with four dimensions of space, nor five, nor six.
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Ne funkcionira niti u svemiru sa četiri prostorne dimenzije, niti pet, niti šest.
11:52
Finally, you can study the equations, and show that it works
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Na kraju, proučavanje formula pokazuje da funkcionira
11:56
only in a universe that has 10 dimensions of space
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samo u svemiru koje ima 10 prostornih dimenzija
12:00
and one dimension of time.
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i jednu vremensku.
12:02
It leads us right back to this idea of Kaluza and Klein --
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I to nas vodi natrag do Kaluzine i Kleinove ideje
12:07
that our world, when appropriately described,
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da naš svijet, ispravno opisan,
12:10
has more dimensions than the ones that we see.
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ima više dimenzija od onih koje vidimo.
12:13
Now you might think about that and say, well,
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Možete o tome razmišljati i reći, dobro,
12:16
OK, you know, if you have extra dimensions, and they're really tightly curled up,
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ako imamo dodatne dimenzija i one su čvrsto uvinute
12:19
yeah, perhaps we won't see them, if they're small enough.
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da, možda ih nećemo vidjeti ako su jako sitne.
12:23
But if there's a little tiny civilization of green people walking around down there,
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Ali ako postoji mala sitna civilizacija zelenih ljudi koja hoda tamo dolje,
12:26
and you make them small enough, and we won't see them either. That is true.
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i ako su oni jako sitni, istina je, nećemo vidjeti ni njih.
12:31
One of the other predictions of string theory --
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Jedno od drugih predviđanja teorije struna --
12:34
no, that's not one of the other predictions of string theory.
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ne, to nije jedno od drugih predviđanja teorije struna.
12:37
(Laughter)
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(Smijeh)
12:38
But it raises the question:
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Ali postavlja se pitanje:
12:40
are we just trying to hide away these extra dimensions,
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pokušavamo li samo sakriti te dodatne dimenzije,
12:42
or do they tell us something about the world?
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ili nam one nešto govore o svijetu?
12:45
In the remaining time, I'd like to tell you two features of them.
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U preostalom vremenu htio bih vam predstaviti dva njihova svojstva.
12:49
First is, many of us believe that these extra dimensions
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Kao prvo, mnogi među nama vjeruju da ove dodatne dimenzije
12:53
hold the answer to what perhaps is the deepest question
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sadrže odgovor na možda najozbiljnije pitanje
12:57
in theoretical physics, theoretical science.
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teorijske fizike, teorijske znanosti.
13:00
And that question is this: when we look around the world,
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A to pitanje glasi: kad pogledamo uokolo po svijetu,
13:04
as scientists have done for the last hundred years,
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kao što znanstvenici rade zadnjih sto godina,
13:06
there appear to be about 20 numbers that really describe our universe.
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čini se da postoji nekih 20 brojeva koji uistinu opisuju svemir.
13:10
These are numbers like the mass of the particles,
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To su brojevi poput mase čestica,
13:13
like electrons and quarks, the strength of gravity,
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poput elektrona i kvarka, jačine gravitacije,
13:15
the strength of the electromagnetic force --
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jačine elektromagnetske sile --
13:17
a list of about 20 numbers
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lista od dvadesetak brojeva
13:19
that have been measured with incredible precision,
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koji su izmjereni s nevjerojatnom preciznošću,
13:22
but nobody has an explanation
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no nitko ne može objasniti
13:24
for why the numbers have the particular values that they do.
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zašto ti brojevi imaju baš tu vrijednost.
13:28
Now, does string theory offer an answer?
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Nudi li teorija struna odgovor?
13:31
Not yet.
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Ne još.
13:32
But we believe the answer for why those numbers have the values they do
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Ali vjerujemo da bi odgovor na pitanje zašto ti brojevi imaju vrijednosti koje imaju
13:36
may rely on the form of the extra dimensions.
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mogao ovisiti o obliku dodatnih dimenzija.
13:39
And the wonderful thing is, if those numbers
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I čudesna činjenica je da kad bi ti brojevi
13:41
had any other values than the known ones,
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imali neku drugu vrijednost od ovih znanih,
13:44
the universe, as we know it, wouldn't exist.
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svemir kakav poznajemo ne bi postojao.
13:47
This is a deep question.
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Ovo je ozbiljno pitanje.
13:48
Why are those numbers so finely tuned
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Zašto su ti brojevi tako fino podešeni
13:50
to allow stars to shine and planets to form,
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da omogućuju zvijezdama da sjaje i planetima da nastaju,
13:52
when we recognize that if you fiddle with those numbers --
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kad shvaćamo da ako se poigramo s tim brojevima --
13:55
if I had 20 dials up here
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kad bih ovdje imao 20 brojčanika
13:57
and I let you come up and fiddle with those numbers,
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i kad bih vam dao da smislite i poigrate se s tim brojevima,
13:59
almost any fiddling makes the universe disappear.
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bilo kakvo poigravanje rezultiralo bi nestankom svemira.
14:03
So can we explain those 20 numbers?
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Dakle, možemo li objasniti tih 20 brojeva?
14:06
And string theory suggests that those 20 numbers
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Teorija struna sugerira da tih 20 brojeva ima
14:08
have to do with the extra dimensions.
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veze s dodatnim dimenzijama.
14:10
Let me show you how.
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Dopustite da vam pokažem kako.
14:12
So when we talk about the extra dimensions in string theory,
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Dakle, kad govorimo o dodatnim dimenzijama u teoriji struna,
14:16
it's not one extra dimension,
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ne govorimo o jednoj dodatnoj dimenziji,
14:18
as in the older ideas of Kaluza and Klein.
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kao u starim idejama Kaluze i Kleina.
14:22
This is what string theory says about the extra dimensions.
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Evo što teorija struna kaže o dodatnim dimenzijama.
14:25
They have a very rich, intertwined geometry.
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Imaju bogato isprepletenu geometriju.
14:28
This is an example of something known as a Calabi-Yau shape --
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Ovo je primjer nečeg poznatog pod nazivom "oblik Calabi-Yau",
14:32
name isn't all that important.
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no ime i nije tako važno.
14:34
But, as you can see,
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Ali kao što možete vidjeti,
14:36
the extra dimensions fold in on themselves
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dodatne dimenzije se savijaju same u sebe
14:39
and intertwine in a very interesting shape, interesting structure.
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i isprepliću se u vrlo zanimljiv oblik, zanimljivu strukturu.
14:43
And the idea is that if this is what the extra dimensions look like,
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Ideja je da ako dodatne dimenzije izgledaju ovako,
14:48
then the microscopic landscape of our universe all around us
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onda bi mikroskopski krajolik svemira oko nas
14:52
would look like this on the tiniest of scales.
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izgledao ovako u najsitnijem mjerilu.
14:54
When you swing your hand,
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Kad zamahnete rukom,
14:55
you'd be moving around these extra dimensions over and over again,
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uvijek biste iznova prolazili kroz ove dodatne dimenzije,
14:58
but they're so small that we wouldn't know it.
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ali one su toliko male da toga ne biste bili svjesni.
15:00
So what is the physical implication, though, relevant to those 20 numbers?
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Koja je, dakle, fizikalna implikacija relevantna za tih 20 brojeva?
15:03
Consider this. If you look at the instrument, a French horn,
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Razmislite o ovome: ako pogledate instrument, francuski rog,
15:06
notice that the vibrations of the airstreams
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vidjet ćete da vibracije zraka
15:09
are affected by the shape of the instrument.
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ovise o obliku instrumenta.
15:11
Now in string theory,
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U teoriji struna,
15:13
all the numbers are reflections of the way strings can vibrate.
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svi brojevi su odrazi načina na koje strune mogu vibrirati.
15:16
So just as those airstreams
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Dakle, kao što su i ta strujanja zraka
15:18
are affected by the twists and turns in the instrument,
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ovisna o zakrivljenosti instrumenta,
15:21
strings themselves will be affected
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i same strune će ovisiti
15:23
by the vibrational patterns in the geometry within which they are moving.
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o vibrirajućim uzorcima u geometriji unutar koje se gibaju.
15:27
So let me bring some strings into the story.
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Dopustite da unesem malo struna u priču,
15:29
And if you watch these little fellows vibrating around --
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Ako pogledate ove male "momke" koji vibriraju uokolo --
15:32
they'll be there in a second -- right there,
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sad će se pojaviti -- evo ovdje,
15:34
notice that they way they vibrate is affected
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pogledajte kako način na koji vibriraju ovisi
15:36
by the geometry of the extra dimensions.
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o geometriji dodatnih dimenzija.
15:38
So, if we knew exactly what the extra dimensions look like --
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Stoga, kad bismo točno znali kako te dodatne dimenzije izgledaju --
15:41
we don't yet, but if we did --
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još ne znamo, ali kad bismo znali --
15:43
we should be able to calculate the allowed notes,
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trebali bismo moći izračunati dozvoljene note,
15:46
the allowed vibrational patterns.
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dozvoljene uzorke vibriranja.
15:48
And if we could calculate the allowed vibrational patterns,
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A kad bismo mogli izračunati dozvoljene uzorke vibriranja,
15:51
we should be able to calculate those 20 numbers.
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trebali bismo biti u stanju izračunati onih 20 brojeva.
15:54
And if the answer that we get from our calculations
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I ako se rezultati koje dobijemo iz naših proračuna
15:58
agrees with the values of those numbers
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slažu s vrijednostima tih brojeva,
16:00
that have been determined
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koje su određene
16:02
through detailed and precise experimentation,
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detaljnim i preciznim eksperimentiranjem,
16:05
this in many ways would be the first fundamental explanation
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to bi na mnoge načine bilo prvo fundamentalno objašnjenje
16:10
for why the structure of the universe is the way it is.
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zašto je struktura svemira onakva kakva je.
16:15
Now, the second issue that I want to finish up with is:
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Nadalje, drugi problem, s kojim bih htio zaključiti, je:
16:18
how might we test for these extra dimensions more directly?
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kako bismo izravnije mogli testirati postojanje dodatnih dimenzija?
16:23
Is this just an interesting mathematical structure
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Je li to samo zanimljiva matematička struktura
16:26
that might be able to explain
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koja bi mogla objasniti
16:28
some previously unexplained features of the world,
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prethodno neobjašnjiva svojstva svijeta,
16:33
or can we actually test for these extra dimensions?
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ili stvarno možemo testirati postojanje tih dodatnih dimenzija?
16:36
And we think -- and this is, I think, very exciting --
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Mislimo -- i ovo je, po mom mišljenju, vrlo uzbudljivo --
16:38
that in the next five years or so we may be able to test
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da bismo u sljedećih pet godina, ili tu negdje, mogli provjeriti
16:42
for the existence of these extra dimensions.
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postojanje tih dodatnih dimenzija.
16:45
Here's how it goes. In CERN, Geneva, Switzerland,
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to izgleda. U CERN-u, u Ženevi, u Švicarskoj,
16:49
a machine is being built called the Large Hadron Collider.
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gradi se stroj nazvan veliki hadronski sudarač.
16:53
It's a machine that will send particles around a tunnel,
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To je uređaj koji će poslati čestice duž kružnog tunela,
16:56
opposite directions, near the speed of light.
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u obrnutim smjerovima, brzinom bliskom brzini svjetlosti.
16:58
Every so often those particles will be aimed at each other,
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Svako malo čestice će biti usmjerene jedna prema drugoj
17:02
so there's a head-on collision.
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tako da dođe do izravnog sudara.
17:04
The hope is that if the collision has enough energy,
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Ako sudar stvori dovoljno energije,
17:08
it may eject some of the debris from the collision
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možda izbaci neke ostatke sudara
17:11
from our dimensions, forcing it to enter into the other dimensions.
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iz naših dimenzija i natjera ih da uđu u druge dimenzije.
17:16
How would we know it?
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Kako ćemo to znati?
17:18
Well, we'll measure the amount of energy after the collision,
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Pa, izmjerit ćemo količinu energije nakon sudara,
17:21
compare it to the amount of energy before,
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usporediti je s količinom prije,
17:23
and if there's less energy after the collision than before,
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i ako nakon sudara energije bude manje nego prije
17:27
this will be evidence that the energy has drifted away.
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to će biti dokaz da je energija nekamo otišla.
17:29
And if it drifts away in the right pattern that we can calculate,
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I ako ode u pravom uzorku koji možemo izračunati,
17:32
this will be evidence that the extra dimensions are there.
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to će biti dokaz da postoje dodatne dimenzije.
17:35
Let me show you that idea visually.
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Dopustite da vam pokažem tu ideju vizualno.
17:37
So, imagine we have a certain kind of particle called a graviton --
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Zamislite da imamo određenu česticu zvanu graviton --
17:40
that's the kind of debris we expect to be ejected out,
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to je ostatak kakav očekujemo da bude izbačen
17:44
if the extra dimensions are real.
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ako dodatne dimenzije postoje.
17:46
But here's how the experiment will go.
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Evo kako bi eksperiment izgledao.
17:47
You take these particles. You slam them together.
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Uzmete ove čestice. Međusobno ih sudarite.
17:50
You slam them together, and if we are right,
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I, ako smo u pravu,
17:52
some of the energy of that collision
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nešto energije od sudara
17:54
will go into debris that flies off into these extra dimensions.
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će otići u ostatak koji odleti u dodatne dimenzije.
17:58
So this is the kind of experiment
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Dakle to je tip eksperimenta
18:00
that we'll be looking at in the next five, seven to 10 years or so.
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koji ćemo provoditi u sljedećih pet, sedam do 10 godina ili tu negdje.
18:04
And if this experiment bears fruit,
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I ako ovaj eksperiment urodi plodom,
18:07
if we see that kind of particle ejected
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ako budemo vidjeli izbacivanje takve čestice
18:10
by noticing that there's less energy in our dimensions
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jer će biti manje energije u našoj dimenziji
18:13
than when we began,
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nego prije početka,
18:15
this will show that the extra dimensions are real.
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pokazat će se da dodatne dimenzija stvarno postoje.
18:18
And to me this is a really remarkable story,
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Za mene je to stvarno izvanredna priča
18:21
and a remarkable opportunity. Going back to Newton with absolute space --
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i izvanredna prilika. Vraćanje Newtonu s apsolutnim prostorom --
18:25
didn't provide anything but an arena, a stage
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nije pružilo ništa osim pozornice
18:27
in which the events of the universe take place.
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na kojoj se odvijaju događaji svemira.
18:29
Einstein comes along and says,
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Dolazi Einstein i kaže:
18:31
well, space and time can warp and curve -- that's what gravity is.
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prostor i vrijeme se mogu uvijati i kriviti, to je gravitacija.
18:34
And now string theory comes along and says,
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A sad dolazi teorija struna i kaže:
18:38
yes, gravity, quantum mechanics, electromagnetism,
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da, gravitacija, kvantna mehanika, elektromagnetizam --
18:41
all together in one package,
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sve je zajedno u jednom paketu,
18:43
but only if the universe has more dimensions than the ones that we see.
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ali samo ako svemir ima više dimenzija nego što ih vidimo.
18:47
And this is an experiment that may test for them in our lifetime.
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Ovo je eksperiment koji bi to mogao provjeriti u toku našeg života.
18:52
Amazing possibility.
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Čudesne mogućnosti.
18:54
Thank you very much.
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Hvala puno.
18:56
(Applause)
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(Pljesak)
ABOUT THE SPEAKER
Brian Greene - PhysicistBrian Greene is perhaps the best-known proponent of superstring theory, the idea that minuscule strands of energy vibrating in a higher dimensional space-time create every particle and force in the universe.
Why you should listen
Greene, a professor of physics and mathematics at Columbia University, has focused on unified theories for more than 25 years, and has written several best-selling and non-technical books on the subject including The Elegant Universe, a Pulitzer finalist, and The Fabric of the Cosmos — each of which has been adapted into a NOVA mini-series. His latest book, The Hidden Reality, explores the possibility that our universe is not the only universe.
Greene believes science must be brought to general audiences in new and compelling ways, such as his live stage odyssey, Icarus at the Edge of Time, with original orchestral score by Philip Glass, and the annual World Science Festival, which he co-founded in 2008 with journalist Tracy Day.
Brian Greene | Speaker | TED.com