Making sense of string theory | Brian Greene

Prevodilac: Ilija Bilic Lektor: Sandra Gojic

In the year 1919,

1919. godine,

a virtually unknown German mathematician, named Theodor Kaluza

gotovo nepoznat nemački matematičar Teodor Kaluza

suggested a very bold and, in some ways, a very bizarre idea.

predstavio je vrlo smelu i na neki način bizarnu ideju.

He proposed that our universe

On je pretpostavio da naš Univerzum

might actually have more than the three dimensions

možda ima više od tri dimenzije,

that we are all aware of.

kojih smo svi svesni.

That is in addition to left, right, back, forth and up, down,

Odnosno, da pored levo-desno, napred-nazad i gore-dole,

Kaluza proposed that there might be additional dimensions of space

mogu postojati dodatne prostorne dimenzije

that for some reason we don't yet see.

koje iz nekog razloga ne možemo da vidimo.

Now, when someone makes a bold and bizarre idea,

Kada neko dođe do tako sulude i bizarne ideje,

sometimes that's all it is -- bold and bizarre,

ponekad je ona samo to - suluda i bizarna

but it has nothing to do with the world around us.

i nema ništa zajedničko sa svetom oko nas.

This particular idea, however --

Ova ideja, međutim,

although we don't yet know whether it's right or wrong,

iako još uvek ne znamo da li je ispravna ili pogrešna,

and at the end I'll discuss experiments which, in the next few years,

a kasnije ću reći nešto o eksperimentima koji, u narednih nekoliko godina,

may tell us whether it's right or wrong --

mogu da nam pokažu da li je ispravna,

this idea has had a major impact on physics in the last century

ova ideja imala je ogroman uticaj na fiziku poslednjeg veka,

and continues to inform a lot of cutting-edge research.

i nastavlja da podstiče najsavremenija istraživanja.

So, I'd like to tell you something about the story of these extra dimensions.

Zato bih voleo da vam ispričam nešto o ovim dimenzijama.

So where do we go?

Međutim, odakle početi?

To begin we need a little bit of back story. Go to 1907.

Za uvod u ovu priču vratićemo se u 1907. godinu.

This is a year when Einstein is basking in the glow

Te godine Ajnštajn je zablistao

of having discovered the special theory of relativity

otkrivši specijalnu teoriju relativiteta,

and decides to take on a new project,

i odlučio da se posveti novom projektu:

to try to understand fully the grand, pervasive force of gravity.

potpunom razmevanju veličanstvene sile gravitacije.

And in that moment, there are many people around

U tom trenutku, mnogi su smatrali da

who thought that that project had already been resolved.

je ta stvar već rešena.

Newton had given the world a theory of gravity in the late 1600s

Njutn je svetu podario teoriju gravitacije krajem 17. veka,

that works well, describes the motion of planets,

koja dobro radi, opisuje kretanje planeta,

the motion of the moon and so forth,

kretanje Meseca i tako dalje,

the motion of apocryphal of apples falling from trees,

nepotvrđenu priču o jabukama koje padaju sa drveća

hitting people on the head.

i udaraju ljude u glavu.

All of that could be described using Newton's work.

Sve to se može opisati i objasniti rezultatima Njutnovog rada.

But Einstein realized that Newton had left something out of the story,

Ali, Ajnštajn je primetio da je Njutn nešto izostavio,

because even Newton had written

jer i sam Njutn je pisao

that although he understood how to calculate the effect of gravity,

o tome kako iako zna da izračuna efekat gravitacije

he'd been unable to figure out how it really works.

ne može sasvim da razume kako ona stvarno funkcioniše.

How is it that the Sun, 93 million miles away,

Kako to da Sunce, 149 miliona kilometara daleko,

[that] somehow it affects the motion of the Earth?

nekako utiče na kretanje Zemlje?

How does the Sun reach out across empty inert space and exert influence?

Na koji način Sunce kroz toliki prazan prostor utiče na Zemlju?

And that is a task to which Einstein set himself --

I to je novi zadatak koji je Ajnštajn postavio sebi -

to figure out how gravity works.

da otkrije kako gravitacija funkcioniše.

And let me show you what it is that he found.

Pokazao bih vam sada šta je Ajnštajn otkrio.

So Einstein found

On je otkrio da je

that the medium that transmits gravity is space itself.

medijum koji provodi gravitaciju sam prostor.

The idea goes like this:

Ideja je sledeća:

imagine space is a substrate of all there is.

zamislite da je prostor supstrat svega što postoji.

Einstein said space is nice and flat, if there's no matter present.

Ajnštajn je rekao da je prostor ravan i gladak ukoliko ne postoji materija.

But if there is matter in the environment, such as the Sun,

Ali, ukoliko postoji materija, kao što je Sunce,

it causes the fabric of space to warp, to curve.

ona izaziva da se sam prostor uvija i krivi.

And that communicates the force of gravity.

I na taj način ispoljava se gravitaciona sila.

Even the Earth warps space around it.

Čak i Zemlja krivi prostor oko sebe.

Now look at the Moon.

Setite se Meseca.

The Moon is kept in orbit, according to these ideas,

Mesec ostaje u svojoj orbiti, prema ovoj ideji, zato što

because it rolls along a valley in the curved environment

se kotrlja niz dolinu u savijenom prostoru,

that the Sun and the Moon and the Earth can all create by virtue of their presence.

koju Sunce i Mesec i Zemlja prave samim svojim prisustvom.

We go to a full-frame view of this.

Pogledajmo celu sliku.

The Earth itself is kept in orbit

Zemlja ostaje u svojoj orbiti

because it rolls along a valley in the environment that's curved

zato što se "kotrlja" niz dolinu u prostoru

because of the Sun's presence.

koja nastaje usled toga što postoji Sunce.

That is this new idea about how gravity actually works.

To je ta nova ideja koja objašnjava gravitaciju.

Now, this idea was tested in 1919 through astronomical observations.

Ta ideja testirana je 1919. godine astronomskim posmatranjima.

It really works. It describes the data.

I ona je stvarno tačna. Potpuno opisuje podatke dobijene posmatranjem.

And this gained Einstein prominence around the world.

To je proslavilo Ajnštajna širom sveta.

And that is what got Kaluza thinking.

I to je navelo Kaluzu na razmišljanje.

He, like Einstein, was in search of what we call a unified theory.

On, kao i Ajnštajn, je tragao za onim što nazivamo "ujedinjujuća teorija".

That's one theory

To je ona teorija koja će moći da objasni

that might be able to describe all of nature's forces from one set of ideas,

sve sile u prirodi samo jednim setom ideja,

one set of principles, one master equation, if you will.

jednim skupom principa... Jednom glavnom jednačinom, ako želite.

So Kaluza said to himself,

Zato je Kaluza rekao sebi sledeće:

Einstein has been able to describe gravity

"Ajnštajn je opisao gravitaciju

in terms of warps and curves in space --

preko zakrivljenja prostora,

in fact, space and time, to be more precise.

ustvari zakrivljenja prostora i vremena, da budemo precizni...

Maybe I can play the same game with the other known force,

Možda ja mogu da se na isti način poigram sa drugom poznatom silom",

which was, at that time, known as the electromagnetic force --

a u to vreme to je bila sila elektromagnetizma.

we know of others today, but at that time

Danas znamo za još neke osnovne sile,

that was the only other one people were thinking about.

ali tada je to bila jedina za koju su ljudi znali.

You know, the force responsible for electricity

Znate je, sila odgovorna za elektricitet

and magnetic attraction and so forth.

i privlačenje magneta i tako dalje.

So Kaluza says, maybe I can play the same game

Dakle, Kaluza kaže sebi da se poigra na isti način

and describe electromagnetic force in terms of warps and curves.

i opiše elektromagnetizam u okvirima zakrivljenja.

That raised a question: warps and curves in what?

Odmah se postavlja pitanje: zakrivljenja čega?

Einstein had already used up space and time,

Ajnštajn je već iskoristio prostor i vreme,

warps and curves, to describe gravity.

njihovo zakrivljenje, kako bi opisao gravitaciju.

There didn't seem to be anything else to warp or curve.

Izgledalo je da ne postoji ništa više da se zakrivi.

So Kaluza said, well, maybe there are more dimensions of space.

Pa je Kaluza rekao: "Pa, možda postoji još prostornih dimenzija.

He said, if I want to describe one more force,

Ukoliko želim da opišem još jednu silu,

maybe I need one more dimension.

možda mi treba još jedna dimenzija."

So he imagined that the world had four dimensions of space, not three,

Tako je zamislio svet sa četiri prostorne dimenzije, umesto tri

and imagined that electromagnetism was warps and curves

i kako elektromagnetizam stvara zakrivljenja

in that fourth dimension. Now here's the thing:

te četvrte dimenzije. Stvar je sada u sledećem:

when he wrote down the equations describing warps and curves

kada je stavio jednačine na papir, one koje opisuju

in a universe with four space dimensions, not three,

zakrivljenja četvorodimenzionog prostora,

he found the old equations that Einstein had already derived in three dimensions --

dobio je iste one jednačine koje je Ajnštajn već ustanovio za trodimenzioni prostor,

those were for gravity --

odnosno one za gravitaciju,

but he found one more equation because of the one more dimension.

ali je dobio još jednu jednačinu, zbog još jedne dimenzije.

And when he looked at that equation,

I kada ju je pogledao,

it was none other than the equation

to je bila ista ona jednačina koju su naučnici

that scientists had long known to describe the electromagnetic force.

već mnogo vremena kotistili da opišu elektromagnetizam.

Amazing -- it just popped out.

Za divno čudo - ona je sama iskočila.

He was so excited by this realization

Ovaj uvid ga je toliko uzbudio

that he ran around his house screaming, "Victory!" --

da je trčao po kući i vikao: "Pobeda!",

that he had found the unified theory.

jer je pronašao ujedinjujuću teoriju.

Now clearly, Kaluza was a man who took theory very seriously.

Kaluza je, očigledno, bio čovek koji je teoriju uzimao veoma ozbiljno.

He, in fact --

Zapravo,

there is a story that when he wanted to learn how to swim,

anegdota kaže da kada je hteo da nauči da pliva,

he read a book, a treatise on swimming --

pročitao je knjigu spisa o plivanju

(Laughter)

(Smeh)

-- then dove into the ocean.

i zaronio u okean.

This is a man who would risk his life on theory.

To je čovek koji bi svoj život rizikovao za teoriju.

Now, but for those of us who are a little bit more practically minded,

Za nas ostale koji smo više orjentisani na praksu,

two questions immediately arise from his observation.

iz njegovog predloga odmah su se pojavila dva pitanja.

Number one: if there are more dimensions in space, where are they?

Prvo: ako postoji više dimenzija prostora - gde su?

We don't seem to see them.

Izgleda da ih ne vidimo.

And number two: does this theory really work in detail,

I drugo: da li je ova teorija zaista ispravna, da li nepogrešivo radi

when you try to apply it to the world around us?

kada pokušamo da je primenimo na svet oko nas?

Now, the first question was answered in 1926

Odgovor na prvo pitanje dao nam je

by a fellow named Oskar Klein.

Oskar Klajn 1926. godine.

He suggested that dimensions might come in two varieties --

On je pretpostavio da dimenzije mogu da postoje u dva oblika:

there might be big, easy-to-see dimensions,

velike - koje je lako uočiti

but there might also be tiny, curled-up dimensions,

i male, sitne, uvijene dimenzije,

curled up so small, even though they're all around us,

koje su toliko sitne da iako su oko nas

that we don't see them.

jednostavno ne možemo da ih vidimo.

Let me show you that one visually.

Pokazaću vam to sada.

So, imagine you're looking at something

Zamislite da gledate u nešto,

like a cable supporting a traffic light.

naprimer u kabl između semafora.

It's in Manhattan. You're in Central Park -- it's kind of irrelevant --

Recimo da ste na Menhetnu, u Central Parku, što i nije važno sada,

but the cable looks one-dimensional from a distant viewpoint,

ali iz vaše tačke gledišta kabl izgleda jednodimenziono,

but you and I all know that it does have some thickness.

ali i vi i ja znamo da on ima neku debljinu.

It's very hard to see it, though, from far away.

Nju je jako teško videti iz daleka.

But if we zoom in and take the perspective of, say,

Ali ako zumiramo pogled i zauzmemo perspektivu, recimo,

a little ant walking around --

malog mrava koji po njemu šeta -

little ants are so small that they can access all of the dimensions --

mali mravi su toliko sitni da mogu da pristupe svim dimenzijama -

the long dimension,

dimenziji dužine,

but also this clockwise, counter-clockwise direction.

ali i kretanja u pravcu kazaljke na satu i suprotno.

And I hope you appreciate this.

Nadam se da ćete znati da cenite ovo.

It took so long to get these ants to do this.

Trebalo je jako mnogo vremena da nateramo mrave da rade ovo.

(Laughter)

(Smeh)

But this illustrates the fact that dimensions can be of two sorts:

Ali ovo ilustruje činjenicu da može da postoji dve vrste dimenzija:

big and small. And the idea that maybe the big dimensions around us

velike i male. A ideja je da su velike dimenzije oko nas

are the ones that we can easily see,

one koje možemo da vidimo

but there might be additional dimensions curled up,

i da mogu da postoje dodatne dimenzije,

sort of like the circular part of that cable,

uvijene kao sam taj kabl,

so small that they have so far remained invisible.

i tako male da su do danas nevidljive.

Let me show you what that would look like.

Pokazaću vam kako bi to moglo da izgleda.

So, if we take a look, say, at space itself --

Ako pogledamo, recimo, sam prostor,

I can only show, of course, two dimensions on a screen.

a na ekranu mogu da vam pokažem samo dve dimenzije,

Some of you guys will fix that one day,

neko će to jednog dana ispraviti,

but anything that's not flat on a screen is a new dimension,

ali sve što nije ravno na ekranu jeste nova dimenzija.

goes smaller, smaller, smaller,

I ako idemo ka sitnijim i sitnijim i sitnijim,

and way down in the microscopic depths of space itself,

sve do mikroskopskih dubina samog prostora,

this is the idea,

ovo je ta ideja:

you could have additional curled up dimensions --

mogu postojati dodatne uvijene dimenzije.

here is a little shape of a circle -- so small that we don't see them.

Ovde je mali krug, toliko mali da ga ne vidimo.

But if you were a little ultra microscopic ant walking around,

Ali ako biste bili ultramikroskopski mrav koji tuda šeta,

you could walk in the big dimensions that we all know about --

mogli biste da se krećete po velikim dimenzijama, koje poznajemo,

that's like the grid part --

to je kao mreža,

but you could also access the tiny curled-up dimension

ali mogli biste i da pristupite malim uvijenim dimenzijama

that's so small that we can't see it with the naked eye

koje su toliko male da ne mogu da se vide ni golim okom

or even with any of our most refined equipment.

ni najfinijom opremom kojom raspolažemo danas.

But deeply tucked into the fabric of space itself,

Ali, duboko uronjene u strukturu samog prostora

the idea is there could be more dimensions, as we see there.

mogu da postoje dodate dimenzije, pored ove tri.

Now that's an explanation

Na taj način objašnjavamo

about how the universe could have more dimensions than the ones that we see.

kako svemir može da ima dodatne dimenzije.

But what about the second question that I asked:

Ali šta je sa drugim pitanjem koje sam postavio:

does the theory actually work

da li teorija zapravo "radi"

when you try to apply it to the real world?

kada pokušamo da je primenimo na realan svet?

Well, it turns out that Einstein and Kaluza and many others

Pa, ispostavlja se da su Ajnštajn i Kaluza i mnogi drugi

worked on trying to refine this framework

radili na usklađivanju ove ideje

and apply it to the physics of the universe

i njenoj primeni u fizici tog vremena,

as was understood at the time, and, in detail, it didn't work.

odnosno tadašnjem razumevanju univerzima i u detaljima, ona nije radila.

In detail, for instance,

Na primer,

they couldn't get the mass of the electron

nisu mogli da izračunaju tačnu masu elektrona

to work out correctly in this theory.

preko ove teorije.

So many people worked on it, but by the '40s, certainly by the '50s,

Jako mnogo ljudi je radilo na tome, ali do 40-ih i svakako 50-ih

this strange but very compelling idea

ova čudna ali izazovna ideja o ujedinjenju zakona fizike

of how to unify the laws of physics had gone away.

je nestala.

Until something wonderful happened in our age.

Sve dok se u naše vreme nešto sjajno nije dogodilo.

In our era, a new approach to unify the laws of physics

Danas imamo novi pristup ujedinjenju zakona fizike,

is being pursued by physicists such as myself,

i time se bavimo ja i drugi fizičari,

many others around the world,

mnogi fizičari širom sveta.

it's called superstring theory, as you were indicating.

To nazivamo teorijom superstruna, kao što ste mogli da pretpostavite.

And the wonderful thing is that superstring theory

Sjajna stvar je da ova teorija

has nothing to do at first sight with this idea of extra dimensions,

na prvi pogled nema ništa sa dodatnim dimenzijama,

but when we study superstring theory,

ali kada je proučavamo,

we find that it resurrects the idea in a sparkling, new form.

uviđamo da ona tu ideju oživljava na jedan sasvim drugi način.

So, let me just tell you how that goes.

Reći ću vam kako to ide.

Superstring theory -- what is it?

Šta je to teorija superstruna?

Well, it's a theory that tries to answer the question:

Pa, to je teorija koja pokušava da odgovori na sledeće pitanje:

what are the basic, fundamental, indivisible, uncuttable constituents

koji su bazični, fundamentalni, nedeljivi činioci

making up everything in the world around us?

koji izgrađuju apsolutno sve oko nas?

The idea is like this.

Ideja je sledeća.

So, imagine we look at a familiar object, just a candle in a holder,

Zamislite da posmatramo poznati objekat, recimo sveću u svećnjaku,

and imagine that we want to figure out what it is made of.

i zamislite da pokušavamo da shvatimo od čega je sastavljena.

So we go on a journey deep inside the object and examine the constituents.

Tako krećemo na put duboko u sam objekat kako bismo ispitali sastavne delove.

So deep inside -- we all know, you go sufficiently far down, you have atoms.

Jako duboko, ovo svi znamo, dolazimo do atoma.

We also all know that atoms are not the end of the story.

Isto tako znamo da atomi nisu kraj priče.

They have little electrons that swarm around a central nucleus

Oni imaju male elektrone koji se kreću oko jezgra

with neutrons and protons.

izgrađenog od protona i neutrona.

Even the neutrons and protons have smaller particles inside of them known as quarks.

Čak i protoni i neutroni sadrže manje čestice, koje smo nazvali kvarkovima.

That is where conventional ideas stop.

Ovde prestaje konvencionalna ideja.

Here is the new idea of string theory.

Sada nastupa teorija struna.

Deep inside any of these particles, there is something else.

Duboko u svakoj od ovih čestica postoji još nešto.

This something else is this dancing filament of energy.

To nešto su male energetske niti.

It looks like a vibrating string --

Izgledaju kao strune koje vibriraju -

that's where the idea, string theory comes from.

iz te ideje proističe ova teorija.

And just like the vibrating strings that you just saw in a cello

I kao što strune koje vidite na violončelu

can vibrate in different patterns,

mogu da vibriraju na različite načine,

these can also vibrate in different patterns.

tako mogu i ove.

They don't produce different musical notes.

One ne proizvode različite tonove,

Rather, they produce the different particles making up the world around us.

već na taj način izgrađuju različite čestice od kojih je izgrađen svet.

So if these ideas are correct,

Tako da, ukoliko su ove ideje tačne,

this is what the ultra-microscopic landscape of the universe looks like.

ovako izgledaju ultramikroskopski pejzaži univerzuma.

It's built up of a huge number

On je izgrađen od ogromnog broja

of these little tiny filaments of vibrating energy,

ovih malih končića vibrirajuće energije,

vibrating in different frequencies.

koja vibrira različitim frekvencijama.

The different frequencies produce the different particles.

Različitim frekvencijama izgrađuju se raziličte čestice.

The different particles are responsible

A različite čestice odgovorne su

for all the richness in the world around us.

za sve bogatstvo sveta oko nas.

And there you see unification,

I tu vidite ujedinjenje -

because matter particles, electrons and quarks,

zato što čestice materije, elektroni i kvarkovi,

radiation particles, photons, gravitons, are all built up from one entity.

čestice zračenja - fotoni; gravitoni - sve su izgrađene od jedne stvari.

So matter and the forces of nature all are put together

Tako su sile prirode i materija spojene,

under the rubric of vibrating strings.

određene samo vibrirajućim strunama.

And that's what we mean by a unified theory.

To je ono što podrazumevamo pod ujedinjujućom teorijom.

Now here is the catch.

E sad, stvar je u sledećem.

When you study the mathematics of string theory,

Kada izučavamo matematiku teorije struna,

you find that it doesn't work

uviđamo da ona ne funkcioniše

in a universe that just has three dimensions of space.

u trodimenzionalnom prostoru.

It doesn't work in a universe with four dimensions of space, nor five, nor six.

Ona ne funkcioniše ni u prostoru sa četiri dimenzije, ni pet, ni šest.

Finally, you can study the equations, and show that it works

Konačno, jednačine imaju smisla

only in a universe that has 10 dimensions of space

samo u prostoru koji ima 10 prostornih

and one dimension of time.

i jednu vremensku dimenziju.

It leads us right back to this idea of Kaluza and Klein --

To nas vraća na ideju Kaluza i Klajna,

that our world, when appropriately described,

da naš svet, kada se ispravno opiše,

has more dimensions than the ones that we see.

ima više dimenzija od onih koje vidimo.

Now you might think about that and say, well,

Vi sada možete da razmislite o tome i kažete sledeće -

OK, you know, if you have extra dimensions, and they're really tightly curled up,

OK, ako imamo dodatne dimenzije i ako su jako uvijene,

yeah, perhaps we won't see them, if they're small enough.

da, onda možda ne možemo da ih vidimo jer su mnogo male.

But if there's a little tiny civilization of green people walking around down there,

Ali ako postoji civilizacija malih zelenih ljudi koja hoda tamo dole,

and you make them small enough, and we won't see them either. That is true.

i ako su i oni toliko mali da ne možemo da ih vidimo, onda je to tačno.

One of the other predictions of string theory --

Još jedno od predviđanja teorije struna.

no, that's not one of the other predictions of string theory.

Ne, to nije još jedno od predviđanja ove teorije.

(Laughter)

(Smeh)

But it raises the question:

Ali postavlja se pitanje:

are we just trying to hide away these extra dimensions,

da li samo pokušavamo da sakrijemo te dimenzije,

or do they tell us something about the world?

to jest, da li nam one govore nešto o svetu?

In the remaining time, I'd like to tell you two features of them.

U vremenu koje nam je preostalo, želeo bih da vam predstavim i dve njihove karakteristike.

First is, many of us believe that these extra dimensions

Prva: mnogi od nas veruju da postojanje ovih dimenzija

hold the answer to what perhaps is the deepest question

krije odgovor na jedno od najdubljih pitanja

in theoretical physics, theoretical science.

teoretske fizike i nauke uopšte.

And that question is this: when we look around the world,

A to pitanje je sledeće: kada gledamo svet oko nas,

as scientists have done for the last hundred years,

kao što to naučnici rade poslednjih sto godina,

there appear to be about 20 numbers that really describe our universe.

čini se da postoji dvadesetak brojeva koji opisuju naš Univerzum.

These are numbers like the mass of the particles,

Ti brojevi su mase pojedinih čestica,

like electrons and quarks, the strength of gravity,

elektrona i kvarkova naprimer, jačina gravitacije,

the strength of the electromagnetic force --

elektromagnetne sile -

a list of about 20 numbers

lista dvadesetak brojeva

that have been measured with incredible precision,

koji su izmereni sa neverovatnom preciznošću.

but nobody has an explanation

Ali niko ne može da objasni zašto ti brojevi

for why the numbers have the particular values that they do.

imaju baš te vrednosti.

Now, does string theory offer an answer?

Da li teorija struna nudi odgovor?

Not yet.

Ne još.

But we believe the answer for why those numbers have the values they do

Ali verujemo da odgovor može da se krije

may rely on the form of the extra dimensions.

u formi tih dodatnih dimenzija.

And the wonderful thing is, if those numbers

I sjajna stvar je sledeća:

had any other values than the known ones,

kada bi ti brojevi bili drugačiji

the universe, as we know it, wouldn't exist.

ovakav Univerzum ne bi postojao.

This is a deep question.

Ovo je duboko pitanje.

Why are those numbers so finely tuned

Zašto su te vrednosti tako fino podešene,

to allow stars to shine and planets to form,

da imamo zvezde koje sijaju i planete oko njih,

when we recognize that if you fiddle with those numbers --

kada znamo da ako se ti brojevi malo izmene -

if I had 20 dials up here

ako biste izmenili

and I let you come up and fiddle with those numbers,

bilo koji od tih brojeva

almost any fiddling makes the universe disappear.

na bilo koji način, onda ceo Univerzum prestaje da postoji.

So can we explain those 20 numbers?

Dakle, možemo li da objasnimo tih 20 brojeva?

And string theory suggests that those 20 numbers

Teorija struna predlaže da su vrednosti tih brojeva

have to do with the extra dimensions.

u vezi sa dodatnim dimenzijama.

Let me show you how.

Pokazaću vam kako.

So when we talk about the extra dimensions in string theory,

Kada govorimo o dodatnim dimenzijama u teoriji struna,

it's not one extra dimension,

ne radi se o jednoj dimenziji,

as in the older ideas of Kaluza and Klein.

kao što su mislili Kaluza i Klajn.

This is what string theory says about the extra dimensions.

Teorija struna nam govori sledeće o dimenzijama:

They have a very rich, intertwined geometry.

njihova geometrija je prilično bogata i isprepletana.

This is an example of something known as a Calabi-Yau shape --

Ovo je primer nečega što je poznato kao Calabi-Yau oblik.

name isn't all that important.

Ime nije naročito važno.

But, as you can see,

Ali kao što možete da vidite,

the extra dimensions fold in on themselves

dodatne dimenzije se upliću oko sebe

and intertwine in a very interesting shape, interesting structure.

i prepliću u interesantne oblike i strukture.

And the idea is that if this is what the extra dimensions look like,

Mi mislimo da ukoliko te dimenzije izgledaju ovako,

then the microscopic landscape of our universe all around us

onda bi ovako izgledao i Univerzum,

would look like this on the tiniest of scales.

uveličan veliki broj puta.

When you swing your hand,

Kada zamahnete rukom,

you'd be moving around these extra dimensions over and over again,

prolazili biste kroz ove dimenzije iznova i iznova,

but they're so small that we wouldn't know it.

ali ih ne biste osetili.

So what is the physical implication, though, relevant to those 20 numbers?

Kakve su, onda, fizičke posledice u vezi sa onih 20 brojeva?

Consider this. If you look at the instrument, a French horn,

Obratite pažnju na ovo. Ako pogledate ovaj instrument, hornu,

notice that the vibrations of the airstreams

vidite da vibracije vazdušnih struja

are affected by the shape of the instrument.

zavise od oblika samog instrumenta.

Now in string theory,

U teoriji struna,

all the numbers are reflections of the way strings can vibrate.

svi ti brojevi su posledica načina na koji strune vibriraju.

So just as those airstreams

Pa kao što na vazdušne struje

are affected by the twists and turns in the instrument,

utiču zakrivljenja samog instrumenta,

strings themselves will be affected

tako će i strune biti pod uticajem

by the vibrational patterns in the geometry within which they are moving.

načina na koji vibriraju unutar geometrije u kojoj se pokreću.

So let me bring some strings into the story.

Pogledajmo sada neke od struna.

And if you watch these little fellows vibrating around --

Ako gledate kako one vibriraju,

they'll be there in a second -- right there,

a sad ćete da ih vidite, evo ih,

notice that they way they vibrate is affected

osmotrite kako je to njihovo vibriranje

by the geometry of the extra dimensions.

pod uticajem geometrije dodatnih dimenzija.

So, if we knew exactly what the extra dimensions look like --

Pa kada bismo znali kako tačno te dimenzije izgledaju,

we don't yet, but if we did --

što još uvek ne znamo, ali kada bismo znali,

we should be able to calculate the allowed notes,

mogli bismo i da izračunamo moguće note,

the allowed vibrational patterns.

odnosno načine na koji mogu da vibriraju.

And if we could calculate the allowed vibrational patterns,

A kada bismo to mogli da izvedemo,

we should be able to calculate those 20 numbers.

onda bismo dobili onih dvadesetak brojeva.

And if the answer that we get from our calculations

I ako se vrednosti koje bismo dobili tim proračunima

agrees with the values of those numbers

slažu sa vrednostima tih brojeva,

that have been determined

koje smo ranije odredili

through detailed and precise experimentation,

kroz detaljne i precizne eksperimente,

this in many ways would be the first fundamental explanation

to bi na mnoge načine bilo prvo fundamentalno objašnjenje

for why the structure of the universe is the way it is.

toga zašto je Univerzum takav kakav je.

Now, the second issue that I want to finish up with is:

Drugi problem i sa time ću završiti, jeste

how might we test for these extra dimensions more directly?

kako možemo da testiramo postojanje tih dimenzija?

Is this just an interesting mathematical structure

Da li je ovo samo interesantan matematički model,

that might be able to explain

koji može da objasni

some previously unexplained features of the world,

ranije neobjašnjiva svojstva sveta,

or can we actually test for these extra dimensions?

ili zapravo možemo da dokažemo postojanje tih dimenzija eksperimentalno?

And we think -- and this is, I think, very exciting --

Mi smatramo, i ja smatram, da je ovo jako uzbudljivo

that in the next five years or so we may be able to test

i da ćemo u narednih pet godina moći da testiramo

for the existence of these extra dimensions.

postojanje tih dodatnih dimenzija.

Here's how it goes. In CERN, Geneva, Switzerland,

Ovako će to da izgleda. U CERN-u, u Ženevi,

a machine is being built called the Large Hadron Collider.

pravimo mašinu koja se zove Veliki sudarač čestica.

It's a machine that will send particles around a tunnel,

Ta mašina će čestice slati kroz tunel

opposite directions, near the speed of light.

u suprotnim pravcima i približno brzinom svetlosti.

Every so often those particles will be aimed at each other,

Te čestice ćemo zatim tako usmeravati

so there's a head-on collision.

da se čeono sudaraju.

The hope is that if the collision has enough energy,

Nadamo se da će ti sudari biti dovoljne energije

it may eject some of the debris from the collision

i da će moći da neke stvari iz naših dimenzija

from our dimensions, forcing it to enter into the other dimensions.

ubace u druge dimenzije.

How would we know it?

Kako ćemo znati da se to dogodilo?

Well, we'll measure the amount of energy after the collision,

Pa, merićemo energiju posle sudara

compare it to the amount of energy before,

i uporediti je sa energijom pre sudara

and if there's less energy after the collision than before,

i ako bude bilo manje energije posle,

this will be evidence that the energy has drifted away.

to će biti dokaz da je deo energije sklonjen.

And if it drifts away in the right pattern that we can calculate,

A ako to budemo mogli da opišemo jednačinama,

this will be evidence that the extra dimensions are there.

to će biti dokaz da dodatne dimenzije postoje.

Let me show you that idea visually.

Pogledajte kako će to da izgleda.

So, imagine we have a certain kind of particle called a graviton --

Zamislite česticu koja se zove graviton,

that's the kind of debris we expect to be ejected out,

to je jedna od stvari koju očekujemo da dobijemo pri sudarima,

if the extra dimensions are real.

ako dodatne dimenzije postoje.

But here's how the experiment will go.

Ovako će eksperiment da izgleda.

You take these particles. You slam them together.

Uzmete čestice i sudarite ih jako.

You slam them together, and if we are right,

Ako smo u pravu,

some of the energy of that collision

deo energije tih sudara

will go into debris that flies off into these extra dimensions.

otići će na prebacivanje u druge dimenzije.

So this is the kind of experiment

Ovakave eksperimente radićemo u narednih

that we'll be looking at in the next five, seven to 10 years or so.

pet, sedam ili desetak godina.

And if this experiment bears fruit,

I ako budu uspešni

if we see that kind of particle ejected

i ako vidimo taj tip čestica

by noticing that there's less energy in our dimensions

i ustanovimo manjak energije u našim dimenzijama,

than when we began,

u odnosu na energiju na početku,

this will show that the extra dimensions are real.

to će biti dokaz da dodatne dimenzije zaista postoje.

And to me this is a really remarkable story,

Za mene je ovo neverovatna priča,

and a remarkable opportunity. Going back to Newton with absolute space --

i neverovatna prilika. Vratimo se na Njutna i apsolutistički prostor -

didn't provide anything but an arena, a stage

koji je samo arena, pozornica

in which the events of the universe take place.

na kojoj se dešava sve u svemiru.

Einstein comes along and says,

Onda dolazi Ajnštajn i kaže sledeće:

well, space and time can warp and curve -- that's what gravity is.

prostor i vreme mogu da se zakrivljuju i to je gravitacija.

And now string theory comes along and says,

Zatim dolazi teorija struna koja kaže:

yes, gravity, quantum mechanics, electromagnetism,

da - gravitacija, kvantna mehanika, elektromagnetizam -

all together in one package,

sve zajedno su u jednom paketu,

but only if the universe has more dimensions than the ones that we see.

ali samo ako Univerzum ima više dimenzija od onih koje vidimo.

And this is an experiment that may test for them in our lifetime.

Ovaj eksperiment će to testirati za vreme naših života.

Amazing possibility.

Neverovatna mogućnost.

Thank you very much.

Hvala vam mnogo.

(Applause)

(Aplauz)