Patricia Burchat: Shedding light on dark matter

Prevodilac: Isidora Bacic Lektor: Ana Stepanenko

As a particle physicist, I study the elementary particles

Kao fizičar čestica, ja proučavam elementarne čestice

and how they interact on the most fundamental level.

i kako one međusobno reaguju na najosnovnijem nivou.

For most of my research career, I've been using accelerators,

Veći deo svoje istraživačke karijere koristim akceleratore,

such as the electron accelerator at Stanford University, just up the road,

kao što je akcelerator elektrona na Univerzitetu Stanford, ovde blizu,

to study things on the smallest scale.

kako bi proučavala stvari na najmanjoj skali.

But more recently, I've been turning my attention

Ali od nedavno, počela sam da se bavim

to the universe on the largest scale.

univerzumom na najvećoj skali.

Because, as I'll explain to you,

Pošto su, kako ću vam objasniti,

the questions on the smallest and the largest scale are actually very connected.

pitanja na najmanjoj i najvećoj skali zapravo veoma povezana.

So I'm going to tell you about our twenty-first-century view of the universe,

Znači pričaću vam o našem viđenju univerzuma u 21. veku,

what it's made of and what the big questions in the physical sciences are --

od čega se sastoji i koja su velika pitanja fizičkih nauka --

at least some of the big questions.

barem neka od velikih pitanja.

So, recently, we have realized

Nedavno smo shvatili

that the ordinary matter in the universe --

da obična materija u univerzumu --

and by ordinary matter, I mean you, me,

i kada kažem obična materija mislim na vas, OK, mene,

the planets, the stars, the galaxies --

planete, zvezde, galaksije --

the ordinary matter makes up only a few percent

obična materija koja čini samo nekoliko procenata

of the content of the universe.

sastava univerzuma.

Almost a quarter, or approximately a quarter

Skoro četvrtina, ili otprilike četvrtina

of the matter in the universe, is stuff that's invisible.

materije u univerzumu, je ono što je nevidljivo.

By invisible, I mean it doesn't absorb in the electromagnetic spectrum.

Kada kažem nevidljivo mislim da ne apsorbuje elektromagnetni spektar.

It doesn't emit in the electromagnetic spectrum. It doesn't reflect.

Ne emituje u elektromagnetni spektar. Ne reflektuje.

It doesn't interact with the electromagnetic spectrum,

Nema interakciju sa elektromagnetnim spektrom,

which is what we use to detect things.

koga koristimo za detekciju stvari.

It doesn't interact at all. So how do we know it's there?

Uopšte nema interakcije. Pa kako onda znamo da je tu?

We know it's there by its gravitational effects.

Znamo da je tu zbog njegovog gravitacionog dejstva.

In fact, this dark matter dominates

Zapravo, ova tamna materija dominira

the gravitational effects in the universe on a large scale,

gravitacionim efektima u univerzumu na velikoj skali,

and I'll be telling you about the evidence for that.

i govoriću vam o dokazima za to.

What about the rest of the pie?

A šta je sa ostatkom kruga?

The rest of the pie is a very mysterious substance called dark energy.

Ostatak kruga je veoma misteriozna supstanca nazvana tamna energija.

More about that later, OK.

Više o tome kasnije, OK.

So for now, let's turn to the evidence for dark matter.

Za sada, hajde da se okrenemo dokazima za tamnu materiju.

In these galaxies, especially in a spiral galaxy like this,

U ovim galaksijama, posebno u spiralnoj galaksiji poput ove,

most of the mass of the stars is concentrated in the middle of the galaxy.

većina mase zvezda je koncentrisana u sredini galaksije.

This huge mass of all these stars keeps stars in circular orbits in the galaxy.

Ova ogromna masa svih ovih zvezda drži zvezde u kružnim orbitama u galaksiji.

So we have these stars going around in circles like this.

Znači imamo ove zvezde koje kruže ovako.

As you can imagine, even if you know physics, this should be intuitive, OK --

Kao što pretpostavljate, čak iako znate fiziku --ovo treba da je intuitivno, OK --

that stars that are closer to the mass in the middle will be rotating at a higher speed

da će se zvezde koje su bliže masi u sredini rotirati većom brzinom

than those that are further out here, OK.

od onih koje su udaljenije, OK.

So what you would expect is that if you measured the orbital speed of the stars,

Ono što biste očekivali jeste da ako biste merili orbitalnu brzinu zvezda,

that they should be slower on the edges than on the inside.

one bi trebalo da budu sporije na ivicama nego unutra.

In other words, if we measured speed as a function of distance --

Drugim rečima, ako bi merili brzinu kao funkciju rastojanja --

this is the only time I'm going to show a graph, OK --

ovo je jedini put da ću prikazati grafikon, OK--

we would expect that it goes down as the distance increases

očekivali bismo da se ona smanjuje kako se rastojanje povećava

from the center of the galaxy.

od centra galaksije.

When those measurements are made,

Kada se ta merenja izvrše,

instead what we find is that the speed is basically constant,

umesto toga nalazimo da je brzina u suštini konstantna,

as a function of distance.

kao funkcija rastojanja.

If it's constant, that means that the stars out here

Ako je konstantna, to znači da zvezde tamo

are feeling the gravitational effects of matter that we do not see.

osećaju gravitaciono dejstvo materije koje mi ne vidimo.

In fact, this galaxy and every other galaxy

Zapravo, ova galaksija i svaka druga galaksija

appears to be embedded in a cloud of this invisible dark matter.

su izgleda ubačene u oblak ove nevidljive tamne materije.

And this cloud of matter is much more spherical than the galaxy themselves,

A ovaj oblak materije je mnogo više sferičan nego same galaksije,

and it extends over a much wider range than the galaxy.

i prostire se preko veće oblasti od galaksije.

So we see the galaxy and fixate on that, but it's actually a cloud of dark matter

Znači vidimo galaksiju i to fiksiramo, ali to je zapravo oblak tamne materije

that's dominating the structure and the dynamics of this galaxy.

koji dominira strukturom i dinamikom ove galaksije.

Galaxies themselves are not strewn randomly in space;

Same galaksije nisu nasumično razbacane po prostoru;

they tend to cluster.

one imaju tendenciju da se grupišu.

And this is an example of a very, actually, famous cluster, the Coma cluster.

I ovo je primer veoma, zapravo, čuvene grupe: Coma grupe.

And there are thousands of galaxies in this cluster.

A postoje hiljade galaksija u ovoj grupi.

They're the white, fuzzy, elliptical things here.

One su ove bele, mutne, eliptične stvari ovde.

So these galaxy clusters -- we take a snapshot now,

Znači ove galaksije se grupišu - sada ih slikamo,

we take a snapshot in a decade, it'll look identical.

i ako ih slikamo za deset godina -- izgledaće isto.

But these galaxies are actually moving at extremely high speeds.

Ali ove galaksije se zapravo kreću veoma visokim brzinama.

They're moving around in this gravitational potential well of this cluster, OK.

One se kreću okolo u ovoj gravitacionoj potencijalnoj jami ove grupe, OK.

So all of these galaxies are moving.

Znači sve ove galaksije se kreću.

We can measure the speeds of these galaxies, their orbital velocities,

Možemo meriti brzine ovih galaksija, njihovu orbitalnu brzinu,

and figure out how much mass is in this cluster.

i izračunati koliko mase postoji u ovoj grupi.

And again, what we find is that there is much more mass there

I ponovo, vidimo da postoji mnogo više mase tu

than can be accounted for by the galaxies that we see.

nego što se može pripisati galaksijama koje vidimo.

Or if we look in other parts of the electromagnetic spectrum,

Ili ako posmatramo druge delove elektromagnetnog spektra,

we see that there's a lot of gas in this cluster, as well.

vidimo da postoji dosta gasa u ovoj grupi takođe.

But that cannot account for the mass either.

Ali ni to ne može objasniti masu.

In fact, there appears to be about ten times as much mass here

Zapravo, izgleda da postoji oko deset puta više mase ovde

in the form of this invisible or dark matter

u obliku ove nevidljive ili tamne materije

as there is in the ordinary matter, OK.

nego što postoji obične materije, OK.

It would be nice if we could see this dark matter a little bit more directly.

Bilo bi lakše kada bismo mogli da direktnije vidimo ovu tamnu materiju.

I'm just putting this big, blue blob on there, OK,

Staviću ovu veliku, plavu mrlju ovde, OK,

to try to remind you that it's there.

da bih vas podsetila da je tu.

Can we see it more visually? Yes, we can.

Da li je možemo jasnije videti? Da, možemo.

And so let me lead you through how we can do this.

Sada ću vam objasniti na koji način to možemo učiniti.

So here's an observer:

Ovo je posmatrač.

it could be an eye; it could be a telescope.

to može biti oko; može biti teleskop.

And suppose there's a galaxy out here in the universe.

I pretpostavimo da postoji galaksija tamo u univerzumu.

How do we see that galaxy?

Kako vidimo tu galaksiju?

A ray of light leaves the galaxy and travels through the universe

Zrak svetlosti napušta galaksiju i putuje kroz univerzum

for perhaps billions of years

možda milijardama godina

before it enters the telescope or your eye.

pre nego što dospe u teleskop ili vaše oko.

Now, how do we deduce where the galaxy is?

Sada, kako zaključujemo gde je ta galaksija?

Well, we deduce it by the direction that the ray is traveling

Pa, zaključujemo prema smeru u kome putuje zrak

as it enters our eye, right?

dok ulazi u naše oko, uredu?

We say, the ray of light came this way;

Kažemo, zrak svetlosti je došao odavde;

the galaxy must be there, OK.

galaksija mora da je tamo, OK.

Now, suppose I put in the middle a cluster of galaxies --

Sada, pretpostavimo da između stavim grupu galaksija --

and don't forget the dark matter, OK.

i ne zaboravite na tamnu materiju, OK.

Now, if we consider a different ray of light, one going off like this,

Sada, ako uzmemo u obzir drugi zrak svetlosti, koji ide ovako,

we now need to take into account

sada moramo uzeti u obzir

what Einstein predicted when he developed general relativity.

Ajnštanova predviđanja iz teorije opšte relativnost.

And that was that the gravitational field, due to mass,

A to je da gravitaciono polje, zbog mase,

will deflect not only the trajectory of particles,

skreće ne samo putanju čestica,

but will deflect light itself.

već skreće i samu svetlost.

So this light ray will not continue in a straight line,

Znači ovaj zrak svetlosti neće nastaviti da ide pravolinijski,

but would rather bend and could end up going into our eye.

već će se saviti i na kraju bi mogao da završi u vašem oku.

Where will this observer see the galaxy?

Gde će posmatrač videti galaksiju?

You can respond. Up, right?

Možete odgovoriti. Gore, jel' tako?

We extrapolate backwards and say the galaxy is up here.

Ekstrapoliramo unazad i kažemo da je galaksija tamo gore.

Is there any other ray of light

Da li postoji neki drugi zrak svetlosti

that could make into the observer's eye from that galaxy?

koji bi mogao da stigne do oka posmatrača iz te galaksije?

Yes, great. I see people going down like this.

Da, super. Vidim ljude koji ovako pokazuju.

So a ray of light could go down, be bent

Znači zrak svetlosti bi mogao da ide na dole, da se savije

up into the observer's eye,

u oko posmatrača,

and the observer sees a ray of light here.

i posmatrač vidi zrak svetlosti ovde.

Now, take into account the fact that we live in

Sada, uzmimo u obzir činjenicu da živimo

a three-dimensional universe, OK,

u trodimenzionalnom univerzumu, OK,

a three-dimensional space.

u trodimenzionalnom prostoru.

Are there any other rays of light that could make it into the eye?

Da li ima još zraka svetlosti koji mogu da dospeju u oko?

Yes! The rays would lie on a -- I'd like to see -- yeah, on a cone.

Da! Zraci bi ležali na --volela bih da vidim --da, na kupi.

So there's a whole ray of light -- rays of light on a cone --

Znači postoje zraci svetlosti -- zraci svetlosti na kupi --

that will all be bent by that cluster

koji će svi biti savijeni tom grupom

and make it into the observer's eye.

i dospeti u oko posmatrača.

If there is a cone of light coming into my eye, what do I see?

Ako postoji kupa svetlosti koja dolazi do mog oka, šta ja vidim?

A circle, a ring. It's called an Einstein ring. Einstein predicted that, OK.

Krug, prsten. To se naziva Ajnštajnovim prstenom -- Ajnštan je to predvideo, OK.

Now, it will only be a perfect ring if the source, the deflector

Sada, to će biti savršeni prsten ako su izvor, prepreka,

and the eyeball, in this case, are all in a perfectly straight line.

i oko, u ovom slučaju, u savršenoj pravoj liniji.

If they're slightly skewed, we'll see a different image.

Ako su malo ukrivo, videćemo drugačiju sliku.

Now, you can do an experiment tonight over the reception, OK,

Sada, možete probati eksperiment večeras na prijemu, OK,

to figure out what that image will look like.

da zaključite kako će ta slika izgledati.

Because it turns out that there is a kind of lens that we can devise,

Jer se ispostavlja da postoji sočivo koje možemo napraviti,

that has the right shape to produce this kind of effect.

koje je odgovarajućeg oblika da stvori tu vrstu efekta.

We call this gravitational lensing.

Ovo nazivamo gravitacionim sočivom.

And so, this is your instrument, OK.

I tako, ovo je vaš instrument, OK.

(Laughter).

(Smeh).

But ignore the top part.

Ali zanemarite gornji deo.

It's the base that I want you to concentrate, OK.

Želim da se koncentrišete na osnovu, OK.

So, actually, at home, whenever we break a wineglass,

Zapravo, kod kuće, kada god slomimo vinsku čašu,

I save the bottom, take it over to the machine shop.

Sačuvam dno, odnesem je do mašinske radionice.

We shave it off, and I have a little gravitational lens, OK.

Skinemo gornji deo i imamo malo gravitaciono sočivo, OK.

So it's got the right shape to produce the lensing.

Znači to je pravi oblik za pravljenje sočiva.

And so the next thing you need to do in your experiment

I sledeća stvar koju želim da uradite u vašem eksperimentu,

is grab a napkin. I grabbed a piece of graph paper -- I'm a physicist. (Laughter)

jeste da uzmete salvetu. Ja sam uzela parče milimetarske hartije. Ja sam ipak fizičar. (Smeh)

So, a napkin. Draw a little model galaxy in the middle.

Znač, salvetu. Nacrtajte mali model galaksije u sredini.

And now put the lens over the galaxy,

I onda stavite sočivo preko galaksije,

and what you'll find is that you'll see a ring, an Einstein ring.

i videćete da ste dobili prsten, Ajnštajnov prsten.

Now, move the base off to the side,

A sada pomerite osnovu na stranu,

and the ring will split up into arcs, OK.

i prsten će se podeliti na lukove, OK.

And you can put it on top of any image.

I možete ga staviti preko bilo koje slike.

On the graph paper, you can see

Na milimetarskoj hartiji možete videti

how all the lines on the graph paper have been distorted.

kako su sve linije na milimetarskoj hartiji izobličene.

And again, this is a kind of an accurate model

I ponovo, ovo je neka vrsta preciznog modela

of what happens with the gravitational lensing.

onoga što se dešava sa gravitacionim sočivom.

OK, so the question is: do we see this in the sky?

OK, znači pitanje je: da li vidimo ovo na nebu?

Do we see arcs in the sky when we look at, say, a cluster of galaxies?

Da li vidimo lukove na nebu kada gledamo, na primer, grupu galaksija?

And the answer is yes.

I odgovor je: da.

And so, here's an image from the Hubble Space Telescope.

I tako, ovo je slika od svemirskog teleskopa Hubble.

Many of the images you are seeing

I mnoge od slika koje gledate

are earlier from the Hubble Space Telescope.

su ranije dobijene sa svemirskog teleskopa Hubble.

Well, first of all, for the golden shape galaxies --

Kao prvo, za galaksije zlatnog oblika --

those are the galaxies in the cluster.

to su galaksije u grupi.

They're the ones that are embedded in that sea of dark matter

To su one ugrađene u more tamne materije

that are causing the bending of the light

koje izazivaju savijanje svetlosti

to cause these optical illusions, or mirages, practically,

da bi izazvale optičke iluzije, fatamorgane, praktično,

of the background galaxies.

galaksija u pozadini.

So the streaks that you see, all these streaks,

Znači crte koje vidite, sve ove crte,

are actually distorted images of galaxies that are much further away.

su zapravo iskrivljene slike galaksija koje su mnogo više udaljene.

So what we can do, then, is based on how much distortion

Ono što možemo je da, onda, na osnovu stepena iskrivljenja

we see in those images, we can calculate how much mass

koje vidimo na tim slikama, izračunamo koliko mase

there must be in this cluster.

mora da postoji u ovoj grupi.

And it's an enormous amount of mass.

A to je ogromna količina mase.

And also, you can tell by eye, by looking at this,

I takođe, možete videti golim okom, dok ovo posmatrate,

that these arcs are not centered on individual galaxies.

da ovi lukovi nisu centrirani u pojedinačnim galaksijama;

They are centered on some more spread out structure,

oni su centrirani u nekoj raširenijoj strukturi.

and that is the dark matter

A to je tamna materija

in which the cluster is embedded, OK.

u kojoj je ugrađena grupa, OK.

So this is the closest you can get to kind of seeing

Znači to je najbliže što možemo doći da vidimo

at least the effects of the dark matter with your naked eye.

barem efekte tamne materije golim okom.

OK, so, a quick review then, to see that you're following.

OK, kratak pregled, da vidim da li pratite.

So the evidence that we have

Znači dokazi koje imamo

that a quarter of the universe is dark matter --

da četvrtinu univerzuma čini tamna materija --

this gravitationally attracting stuff --

ono što privlači putem gravitacije --

is that galaxies, the speed with which stars orbiting galaxies

jeste da galaksije, brzine kojim zvezde orbitiraju oko galaksija

is much too large; it must be embedded in dark matter.

jesu prevelike; mora da bude ugrađena u tamnu materiju.

The speed with which galaxies within clusters are orbiting is much too large;

Brzina kojom galaksije u okviru grupa orbitiraju je prevelika;

it must be embedded in dark matter.

mora da je ugrađena u tamnu materiju.

And we see these gravitational lensing effects, these distortions

I vidimo ove efekte gravitacionog sočiva, ova izobličenja

that say that, again, clusters are embedded in dark matter.

koja ponovo ukazuju da su grupe ugrađene u tamnu materiju.

OK. So now, let's turn to dark energy.

OK. Hajde sada da se bavimo tamnom energijom.

So to understand the evidence for dark energy, we need to discuss something

Da bi razumeli dokaze za tamnu energiju, potrebno je razmotriti nešto

that Stephen Hawking referred to in the previous session.

što je Stephen Hawking spomenuo u prethodnoj sesiji.

And that is the fact that space itself is expanding.

A to je činjenica da se sam prostor širi.

So if we imagine a section of our infinite universe --

Znači ako zamislimo deo našeg beskonačnog univerzuma, OK,

and so I've put down four spiral galaxies, OK --

pa sam ovde stavila četiri spiralne galaksije, OK.

and imagine that you put down a set of tape measures,

I zamislimo da stavite nekoliko metara za merenje,

so every line on here corresponds to a tape measure,

tako da se svaka linija ovde poklapa sa metrom za merenje --

horizontal or vertical, for measuring where things are.

horizontalno ili vertikalno -- za merenje gde se šta nalazi.

If you could do this, what you would find

Ako biste to mogli da uradite, videli biste

that with each passing day, each passing year,

svakim danom, svakom godinom,

each passing billions of years, OK,

svakom milijardom godina, OK,

the distance between galaxies is getting greater.

da se rastojanje između galaksija povećava.

And it's not because galaxies are moving

A to nije zato šte se galaksije

away from each other through space.

međusobno udaljuju kroz svemir;

They're not necessarily moving through space.

nije baš da se kreću kroz svemir.

They're moving away from each other

One se međusobno udaljavaju

because space itself is getting bigger, OK.

jer se sam svemir povećava, OK.

That's what the expansion of the universe or space means.

To znači širenje univerzuma ili prostora.

So they're moving further apart.

Znači one se udaljavaju.

Now, what Stephen Hawking mentioned, as well,

Sada, ono što je Stephen Hawking pomenuo, takođe,

is that after the Big Bang, space expanded at a very rapid rate.

jeste da se nakon Velikog praska, prostor širio veoma velikom brzinom.

But because gravitationally attracting matter

Ali pošto je materija koja ima gravitaciono privlačenje

is embedded in this space,

ugrađena u ovaj prostor,

it tends to slow down the expansion of the space, OK.

ona ima tendenciju da usporava širenje prostora, OK.

So the expansion slows down with time.

Znači širenje se usporava s vremenom.

So, in the last century, OK, people debated

Znači, u prošlom veku, ljudi su raspravljali

about whether this expansion of space would continue forever;

o tome da li će se ovo širenje prostora nastaviti zauvek,

whether it would slow down, you know,

da li će se usporiti, znate,

will be slowing down, but continue forever;

da li će se usporavati, ali nastavljati zauvek.

slow down and stop, asymptotically stop;

Usporiti i stati, asimptotski stati,

or slow down, stop, and then reverse, so it starts to contract again.

ili usporiti, zaustaviti, a onda, obratno ponovo početi da se skuplja.

So a little over a decade ago,

Pre nešto više od jedne decenije,

two groups of physicists and astronomers

dve grupe fizičara i astronoma

set out to measure the rate at which

su počeli da mere stopu po kojoj

the expansion of space was slowing down, OK.

se širenje prostora usporava, OK.

By how much less is it expanding today,

Za koliko manje se širi danas,

compared to, say, a couple of billion years ago?

u poređenju sa, na primer, pre par milijardi godina?

The startling answer to this question, OK, from these experiments,

Zapanjujući odgovor na ovo pitanje, iz ovih eksperimenata,

was that space is expanding at a faster rate today

jeste da se prostor širi brže danas,

than it was a few billion years ago, OK.

nego pre nekoliko milijardu godina, OK.

So the expansion of space is actually speeding up.

Znači širenje prostora se zapravo ubrzava.

This was a completely surprising result.

Ovo je bio potpuno iznenađujući rezultat.

There is no persuasive theoretical argument for why this should happen, OK.

Ne postoji ubedljiv teorijski argument zašto se ovo događa, OK.

No one was predicting ahead of time this is what's going to be found.

Niko nije unapred predvideo da će se to utvrditi.

It was the opposite of what was expected.

Očekivalo se upravo suprotno.

So we need something to be able to explain that.

Zato nam je potrebno nešto što će moći to da objasni.

Now it turns out, in the mathematics,

Sada ispada, u matematici,

you can put it in as a term that's an energy,

možete to nazvati vrstom energije.

but it's a completely different type of energy

Ali to je potpuno drugačija vrsta energije

from anything we've ever seen before.

od bilo čega što smo do sada videli.

We call it dark energy,

Mi to nazivamo tamnom energijom,

and it has this effect of causing space to expand.

i ima dejstvo da izazove da se prostor širi.

But we don't have a good motivation

Ali nemamo dobar razlog

for putting it in there at this point, OK.

da to uvedemo u ovom trenutku, OK.

So it's really unexplained as to why we need to put it in.

Znači potpuno je neobjašnjeno zašto moramo da to unesemo.

Now, so at this point, then, what I want to really emphasize to you,

Sada, u ovom trenutku, onda, ono što želim da vam naglasim,

is that, first of all, dark matter and dark energy

jeste da su kao prvo, tamna materija i tamna energija

are completely different things, OK.

potpuno različite stvari, OK.

There are really two mysteries out there as to what makes up most of the universe,

Postoje stvarno dve misterije o tome šta čini veći deo univerzuma,

and they have very different effects.

i one imaju veoma različita dejstva.

Dark matter, because it gravitationally attracts,

Tamna materija, pošto gravitaciono privlači,

it tends to encourage the growth of structure, OK.

ima tendenciju da ohrabruje rast strukture, OK.

So clusters of galaxies will tend to form,

Tako da će grupe galaksija imati tendenciju da se formiraju,

because of all this gravitational attraction.

zbog ovog gravitacionog privlačenja.

Dark energy, on the other hand,

Tamna energija, s druge strane,

is putting more and more space between the galaxies,

stvara sve više i više prostora između galaksija.

makes it, the gravitational attraction between them decrease,

Čini da se - gravitaciona privlačnost među njima - smanjuje,

and so it impedes the growth of structure.

i tako ometa rast strukture.

So by looking at things like clusters of galaxies,

I tako posmatrajući stvari poput grupa galaksija,

and how they -- their number density,

i kako one -- njihov broj gustine,

how many there are as a function of time --

koliko ih ima kao funkcija vremena --

we can learn about how dark matter and dark energy

učimo o tome kako se tamna materija i tamna energija

compete against each other in structure forming.

međusobno takmiče u formiranju strukture.

In terms of dark matter, I said that we don't have any,

Što se tiče tamne materije, rekla sam da nemamo,

you know, really persuasive argument for dark energy.

znate, stvarno ubedljiv argument za tamnu energiju.

Do we have anything for dark matter? And the answer is yes.

Da li imamo nešto za tamnu materiju? I odogovor je: da.

We have well-motivated candidates for the dark matter.

Imamo dobro motivisane kandidate za tamnu materiju.

Now, what do I mean by well motivated?

Šta znači dobro motivisane?

I mean that we have mathematically consistent theories

Mislim da imamo matematički konzistentne teorije

that were actually introduced

koje su zapravo uvedene

to explain a completely different phenomenon, OK,

da objasne potpuno različite fenomene, OK,

things that I haven't even talked about,

stvari o kojima nisam čak ni govorila,

that each predict the existence

koje previđaju postojanje

of a very weakly interacting, new particle.

veoma slabo reagujuće nove čestice.

So, this is exactly what you want in physics:

Zapravo ovo je baš ono što želite u fizici:

where a prediction comes out of a mathematically consistent theory

kada previđanje potekne iz matematički konzistentne teorije

that was actually developed for something else.

koja je zapravo razvijena za nešto drugo.

But we don't know if either of those

Ali mi ne znamo da li je ijedna od ovih

are actually the dark matter candidate, OK.

stvarno kandidat za tamnu materiju, OK.

One or both, who knows? Or it could be something completely different.

Jedna, ili obe, ko zna? Ili je možda nešto potpuno drugačije.

Now, we look for these dark matter particles

Sada tražimo ove čestice tamne materije

because, after all, they are here in the room, OK,

jer ipak, one su ovde u sobi, OK,

and they didn't come in the door.

a nisu ušle kroz vrata.

They just pass through anything.

One jednostavno prolaze kroz bilo šta.

They can come through the building, through the Earth --

One mogu proći kroz zgradu, kroz zemlju;

they're so non-interacting.

one nemaju interakciju.

So one way to look for them is to build detectors

Znači jedan način da ih posmatramo jeste da izgradimo detektore

that are extremely sensitive to a dark matter particle coming through and bumping it.

koji su izuzetno osetljivi na tamne čestice koje prolaze kroz i sudaraju se s njima.

So a crystal that will ring if that happens.

Znači kristal koji će zvoniti ako se to dogodi.

So one of my colleagues up the road and his collaborators

Pa su jedan moj kolega ovde niz ulicu i njegovi saradnici

have built such a detector.

sagradili takav detektor.

And they've put it deep down in an iron mine in Minnesota,

I postavili ga duboko u rudniku gvožđa u Minesoti,

OK, deep under the ground, and in fact, in the last couple of days

OK? -- duboko pod zemljom -- i zapravo, u poslednjih nekoliko dana

announced the most sensitive results so far.

su objavili najosetljivije rezultate do sada.

They haven't seen anything, OK, but it puts limits on what the mass

Ništa nisu videli, OK, ali to postavlja granice onoga što su masa

and the interaction strength of these dark matter particles are.

i snaga interakcija ovih čestica tamne materije.

There's going to be a satellite telescope launched later this year

Biće lansiran satelitski teleskop kasnije ove godine.

and it will look towards the middle of the galaxy,

I biće uperen ka središtu galaksije,

to see if we can see dark matter particles annihilating

tako da možemo da vidimo čestice tamne materije kako uništavaju

and producing gamma rays that could be detected with this.

i proizvode gama zrake koji bi mogli da se ovim detektuju.

The Large Hadron Collider, a particle physics accelerator,

Veliki hadronski sudarač, akcelerator čestica,

that we'll be turning on later this year.

koji će biti uključen kasnije ove godine.

It is possible that dark matter particles might be produced

Moguće je da će nastati čestice tamne materije

at the Large Hadron Collider.

u Velikom hadronskom sudaraču.

Now, because they are so non-interactive,

Sada, pošto su toliko neinteraktivne,

they will actually escape the detector,

one će zapravo pobeći detektoru,

so their signature will be missing energy, OK.

pa će njihov otisak biti energija koja nedostaje, OK.

Now, unfortunately, there is a lot of new physics

Nažalost, ima mnogo nove fizike

whose signature could be missing energy,

čiji bi otisak takođe mogao biti energija koja nedostaje,

so it will be hard to tell the difference.

pa će biti teško napraviti razliku.

And finally, for future endeavors, there are telescopes being designed

I na kraju, za buduće napore, prave se teleskopi

specifically to address the questions of dark matter and dark energy --

konkretno da se bave pitanjima tamne materije i tamne energije:

ground-based telescopes, and there are three space-based telescopes

teleskopi koji će biti na zemlji. I postoji tri teleskopa baziranih u svemiru

that are in competition right now

koji su sada u konkurenciji

to be launched to investigate dark matter and dark energy.

da se lansiraju kako bi ispitivali tamnu materiju i tamnu energiju.

So in terms of the big questions:

Znači što se tiče velikih pitanja:

what is dark matter? What is dark energy?

Šta je tamna materija? Šta je tamna energija?

The big questions facing physics.

Velika pitanja sa kojima je suočena fizika.

And I'm sure you have lots of questions,

I sigurna sam da vi imate puno pitanja.

which I very much look forward to addressing

Na koja ću rado odgovoriti

over the next 72 hours, while I'm here. Thank you.

tokom sledećih 72 sata dok sam ovde, OK. Hvala.

(Applause)

(Aplauz)