Sean Carroll: Distant time and the hint of a multiverse

Translator: Erik Ušaj Reviewer: Tilen Pigac - EFZG

The universe

Vesolje

is really big.

je res veliko.

We live in a galaxy, the Milky Way Galaxy.

Živimo v galaksiji, v Galaksiji Rimska cesta.

There are about a hundred billion stars in the Milky Way Galaxy.

Tu je približno sto milijard zvezd.

And if you take a camera

In če vzamemo kamero

and you point it at a random part of the sky,

in jo usmerimo v naključno točko na nebu,

and you just keep the shutter open,

in pustimo odprto zaslonko,

as long as your camera is attached to the Hubble Space Telescope,

seveda, če je naša kamera pripeta na vesoljski teleskop Hubble,

it will see something like this.

bomo videli nekaj takega.

Every one of these little blobs

In v vsaki teh lis

is a galaxy roughly the size of our Milky Way --

je galaksija približno velikosti naše Rimske ceste --

a hundred billion stars in each of those blobs.

sto milijard zvezd v vsaki taki lisi.

There are approximately a hundred billion galaxies

V vidnem vesolju je približno

in the observable universe.

sto milijard galaksij.

100 billion is the only number you need to know.

100 milijard je edino število, ki si ga moramo zapomniti.

The age of the universe, between now and the Big Bang,

Starost vesolja, med zdaj in Velikim Pokom

is a hundred billion in dog years.

je sto milijard v pasjih letih.

(Laughter)

(Smeh)

Which tells you something about our place in the universe.

Kar nam pove nekaj o našem mestu v vesolju.

One thing you can do with a picture like this is simply admire it.

Nekaj, kar naredimo s tako sliko, je preprosto občudovanje.

It's extremely beautiful.

To je izjemna lepota.

I've often wondered, what is the evolutionary pressure

Pogosto sem se spraševal, kakšen je pritisk evolucije

that made our ancestors in the Veldt adapt and evolve

ki je naše prednike izoblikoval do te mere

to really enjoy pictures of galaxies

da so uživali v slikah galaksij

when they didn't have any.

čeprav jih niso imeli.

But we would also like to understand it.

Toda mi bi jih radi tudi razumeli.

As a cosmologist, I want to ask, why is the universe like this?

Kot kosmolog, želim vprašati: Zakaj je vesolje takšno?

One big clue we have is that the universe is changing with time.

Velik namig, ki ga imamo, je da se vesolje spreminja skozi čas.

If you looked at one of these galaxies and measured its velocity,

Če bi gledali v eno teh galaksij in izmerili njeno hitrost,

it would be moving away from you.

bi se odmikala od nas.

And if you look at a galaxy even farther away,

In če se zazremo še v bolj oddaljeno galaksijo,

it would be moving away faster.

se le-ta odmika še hitreje.

So we say the universe is expanding.

Zato pravimo, da se vesolje širi.

What that means, of course, is that, in the past,

In to seveda pomeni, da so bile v preteklosti,

things were closer together.

vse stvari bližje skupaj.

In the past, the universe was more dense,

V preteklosti je bilo vesolje gostejše,

and it was also hotter.

in bilo je bolj vroče.

If you squeeze things together, the temperature goes up.

Če stisnemo stvari skupaj, temperatura naraste.

That kind of makes sense to us.

To se nam zdi smiselno.

The thing that doesn't make sense to us as much

Kar se nam ne zdi tako smiselno

is that the universe, at early times, near the Big Bang,

je, da je bilo vesolje, v zgodnji dobi, skoraj ob Velikem Poku,

was also very, very smooth.

tudi zelo gladko, enakomerno.

You might think that that's not a surprise.

Morda boste pomislili, da to ni presenetljivo.

The air in this room is very smooth.

Tudi zrak v tem prostoru je zelo enakomeren.

You might say, "Well, maybe things just smoothed themselves out."

Lahko rečete: "No, morda se stvari same uredijo".

But the conditions near the Big Bang are very, very different

Toda razmere ob Velikem Poku, so bile zelo, zelo drugačne

than the conditions of the air in this room.

kot so razmere zraka v tem prostoru.

In particular, things were a lot denser.

Še posebej, stvari so bile zelo gostejše.

The gravitational pull of things

Gravitacijske sile stvari

was a lot stronger near the Big Bang.

so bile močnejše ob Velikem Poku.

What you have to think about

Kar lahko razmislimo

is we have a universe with a hundred billion galaxies,

je, da imamo vesolje z sto milijardami galaksij

a hundred billion stars each.

in v vsaki sto milijard zvezd.

At early times, those hundred billion galaxies

V zgodnjih časih, so bile te milijarde galaksij

were squeezed into a region about this big --

stisnjene v območje približno te velikosti --

literally -- at early times.

dobesedno, v zgodnjih časih.

And you have to imagine doing that squeezing

In predstavljajte si tako stiskanje

without any imperfections,

brez kakršnih koli nepopolnosti,

without any little spots

brez nobenih malih točk

where there were a few more atoms than somewhere else.

kjer bi bilo nekaj manj atomov, kot nekje drugje.

Because if there had been, they would have collapsed under the gravitational pull

Kajti, če bi bile, bi se zrušile pod gravitacijsko silo

into a huge black hole.

v ogromno črno luknjo.

Keeping the universe very, very smooth at early times

Ohranjanje zelo enakomernega vesolja v zgodnjih časih

is not easy; it's a delicate arrangement.

ni preprosto, je občutljiva ureditev.

It's a clue

To je namig,

that the early universe is not chosen randomly.

da zgodnje vesolje ni izbrano naključno.

There is something that made it that way.

Tu je nekaj, kar ga je ustvarilo na ta način.

We would like to know what.

In mi bi radi vedeli kaj.

So part of our understanding of this was given to us by Ludwig Boltzmann,

Torej del našega razumevanja nam je podal Ludwig Boltzmann,

an Austrian physicist in the 19th century.

austrijski fizik v 19. stoletju.

And Boltzmann's contribution was that he helped us understand entropy.

In Boltzmannov prispevek nam je pomagal razumeti entropijo.

You've heard of entropy.

Slišali ste za entropijo.

It's the randomness, the disorder, the chaoticness of some systems.

To je naključje, nered, kaotičnost nekih sistemov.

Boltzmann gave us a formula --

Boltzmann nam je podal formulo --

engraved on his tombstone now --

danes vklesano na njegov nagrobnik --

that really quantifies what entropy is.

ki količinsko določa kaj je entropija.

And it's basically just saying

In v bistvu pravi le,

that entropy is the number of ways

da je entropija število načinov,

we can rearrange the constituents of a system so that you don't notice,

s katerimi lahko prerazporedimo sestavine sistema, tako da se ne opazi,

so that macroscopically it looks the same.

tako, da makroskopsko zgleda enako.

If you have the air in this room,

Če vzamemo zrak v tej sobi,

you don't notice each individual atom.

ne opazimo vsakega posameznega atoma.

A low entropy configuration

Nizka konfiguracija entropije

is one in which there's only a few arrangements that look that way.

je taka, v kateri je samo nekaj postavitev, ki zgledajo tako.

A high entropy arrangement

Visoka ureditev entropije

is one that there are many arrangements that look that way.

je taka, kjer je več možnih postavitev, ki zgledajo tako.

This is a crucially important insight

To je ključnega pomena,

because it helps us explain

ker nam pomaga razložiti

the second law of thermodynamics --

drugi zakon termodinamike --

the law that says that entropy increases in the universe,

zakon, ki pravi, da entropija v vesolju narašča.

or in some isolated bit of the universe.

ali v omejenem delčku vesolja.

The reason why entropy increases

Razlog za naraščanje entropije

is simply because there are many more ways

je preprost, ker je veliko več načinov

to be high entropy than to be low entropy.

za doseganje visoke entropije, kot nizke entropije.

That's a wonderful insight,

To je čudovito razumevanje,

but it leaves something out.

vendar nekaj manjka.

This insight that entropy increases, by the way,

Razumevanje, da entropija narašča, mimogrede,

is what's behind what we call the arrow of time,

kar je za nami imenujemo časovni vektor,

the difference between the past and the future.

razlika med preteklostjo in prihodnjostjo.

Every difference that there is

Vsaka razlika

between the past and the future

med preteklostjo in prihodnjostjo

is because entropy is increasing --

je zaradi naraščanja entropije --

the fact that you can remember the past, but not the future.

dejstvo, da se lahko spomnimo preteklosti, toda ne prihodnosti.

The fact that you are born, and then you live, and then you die,

Dejstvo, da se rodimo, živimo in umremo,

always in that order,

vedno v tem vrstnem redu,

that's because entropy is increasing.

to je zaradi naraščanja entropije.

Boltzmann explained that if you start with low entropy,

Boltzmann je razložil tudi, da če začnemo z nizko entropijo,

it's very natural for it to increase

je zelo naravno, da se poveča,

because there's more ways to be high entropy.

ker je veliko več načinov za stanja z visoko entropijo.

What he didn't explain

Kar pa ni razložil,

was why the entropy was ever low in the first place.

je zakaj je bila entropija vedno nizka v izhodišču.

The fact that the entropy of the universe was low

Dejstvo, da je bila entropija vesolja nizka

was a reflection of the fact

je odsev dejstva

that the early universe was very, very smooth.

da je bilo prvotno vesolje zelo enakomerno.

We'd like to understand that.

To bi radi razumeli.

That's our job as cosmologists.

To je naloga nas kozmologov.

Unfortunately, it's actually not a problem

Nažalost, to ni problem,

that we've been giving enough attention to.

ki smo mu namenili dovolj pozornosti.

It's not one of the first things people would say,

To ni en izmed prvih odgovorov, ki ga slišiš,

if you asked a modern cosmologist,

če vprašaš sodobnega kozmologa:

"What are the problems we're trying to address?"

"Katere probleme poskušate rešiti?"

One of the people who did understand that this was a problem

Nekdo, ki je razumel, da je to problem

was Richard Feynman.

je bil Richard Feynman.

50 years ago, he gave a series of a bunch of different lectures.

Pred 50 leti, je imel serijo rezličnih predavanj.

He gave the popular lectures

Predaval je na priljubljenih predavanjih

that became "The Character of Physical Law."

ki so postali "Karakter fizikalnih zakonov".

He gave lectures to Caltech undergrads

Predaval je študentom na Caltechu,

that became "The Feynman Lectures on Physics."

danes znanimi kot "Feynmanova predavanja o fiziki".

He gave lectures to Caltech graduate students

Predaval je Caltech-ovim podiplomantom,

that became "The Feynman Lectures on Gravitation."

kar poznamo kot "Feynmanova predavanja o gravitaciji".

In every one of these books, every one of these sets of lectures,

V vsaki izmed teh knjig, vsaki zbirki predavanj,

he emphasized this puzzle:

je povdarjal vprašanje:

Why did the early universe have such a small entropy?

Zakaj je imelo zgodnje vesolje tako majhno entropijo?

So he says -- I'm not going to do the accent --

Tako pravi -- In ne bom naglaševal --

he says, "For some reason, the universe, at one time,

pravi: "Zaradi nekega vzroka, je vesolje, v nekem času,

had a very low entropy for its energy content,

imelo zelo nizko entropijo za svojo energijsko vsebnost,

and since then the entropy has increased.

in odtlej je entropija naraščala.

The arrow of time cannot be completely understood

Časovnega vektorja ne moremo povsem razumeti

until the mystery of the beginnings of the history of the universe

dokler skrivnost začetka zgodovine vesolja

are reduced still further

ni dokončno zmanjšana

from speculation to understanding."

iz špekulacije v razumevanje".

So that's our job.

To je naša naloga.

We want to know -- this is 50 years ago, "Surely," you're thinking,

Želimo vedeti -- to je bilo pred 50 leti in razmišljate: "Seveda

"we've figured it out by now."

do danes smo to rezrešili".

It's not true that we've figured it out by now.

Ni res, da smo do danes to rezrešili.

The reason the problem has gotten worse,

Problem je postal še večji

rather than better,

namesto lažji,

is because in 1998

ker smo v letu 1998

we learned something crucial about the universe that we didn't know before.

spoznali nekaj ključnega o vesolju, česar doslej nismo vedeli.

We learned that it's accelerating.

Spoznali smo, da vesolje pospešuje.

The universe is not only expanding.

Vesolje se ne samo širi.

If you look at the galaxy, it's moving away.

Če pogledate galaksije, se oddaljujejo.

If you come back a billion years later and look at it again,

Če se vrnemo čez milijard let in spet pogledamo,

it will be moving away faster.

se galaksije oddaljujejo še hitreje.

Individual galaxies are speeding away from us faster and faster

Posamezne galaksije drvijo stran od nas hitreje in hitreje.

so we say the universe is accelerating.

Tako pravimo, da vesolje pospešuje.

Unlike the low entropy of the early universe,

Za razliko od nizke entropije zgodnjega vesolja,

even though we don't know the answer for this,

čeprav ne poznamo odgovora na to,

we at least have a good theory that can explain it,

imamo vsaj dobro terorijo, ki nam to lahko razloži,

if that theory is right,

in če je teorija pravilna,

and that's the theory of dark energy.

je to teorija temne energije.

It's just the idea that empty space itself has energy.

Je le ideja, da ima tudi prazen prostor energijo.

In every little cubic centimeter of space,

V vsakem malem kubičnem centimetru prostora,

whether or not there's stuff,

neglede na to kaj vsebuje,

whether or not there's particles, matter, radiation or whatever,

neglede ali so ali ni delcev, materije, sevanja ali česarkoli,

there's still energy, even in the space itself.

še vedno je prisotna energija v samem prostoru.

And this energy, according to Einstein,

In ta energija, po Einsteinu

exerts a push on the universe.

izvaja potisk na vesolje.

It is a perpetual impulse

To je ponavljajoč impulz,

that pushes galaxies apart from each other.

ki potiska galaksije narazen eno od druge.

Because dark energy, unlike matter or radiation,

Ker se temna energija, za razliko od snovi ali sevanja,

does not dilute away as the universe expands.

ne razredči medtem, ko se vesolje širi.

The amount of energy in each cubic centimeter

Količina energije v vsakem kubičnem centimetru

remains the same,

ostaja enaka,

even as the universe gets bigger and bigger.

tudi, ko se vesolje veča in veča.

This has crucial implications

To ima ključne posledice

for what the universe is going to do in the future.

na obnašanje vesolja v prihodnjosti.

For one thing, the universe will expand forever.

Ena stvar: vesolje se bo večno širilo.

Back when I was your age,

Ko sem bil vaše starosti,

we didn't know what the universe was going to do.

nismo vedeli, kaj se bo zgodilo z vesoljem.

Some people thought that the universe would recollapse in the future.

Nekateri so mislili, da se bo vesolje v prihodnosti sesedlo.

Einstein was fond of this idea.

Einsteinu je bila ta ideja všeč.

But if there's dark energy, and the dark energy does not go away,

Toda če je temna energija, in če temna energija ne gre stran,

the universe is just going to keep expanding forever and ever and ever.

se bo vesolje le širilo in širilo za vse večne čase.

14 billion years in the past,

14 milijard let nazaj,

100 billion dog years,

100 milijard pasjih let,

but an infinite number of years into the future.

toda neskončno število let v prihodnjost.

Meanwhile, for all intents and purposes,

Medtem, za vse namene in namere,

space looks finite to us.

prostor vidimo kot končen.

Space may be finite or infinite,

Prostor je lahko končen ali neskončen,

but because the universe is accelerating,

vendar, ker vesolje pospešuje,

there are parts of it we cannot see

so predeli, ki jih ne moremo videti

and never will see.

in jih nikoli ne bomo videli.

There's a finite region of space that we have access to,

Imamo dostop le do končnega območja vesolja,

surrounded by a horizon.

ki ga obkroža obzorje.

So even though time goes on forever,

Tudi če je čas neskončen,

space is limited to us.

je prostor za nas omejen.

Finally, empty space has a temperature.

Končno, prazen prostor ima temperaturo.

In the 1970s, Stephen Hawking told us

1970 nam je Stephen Hawking povedal,

that a black hole, even though you think it's black,

da črna luknja, čeprav mislimo, da je črna,

it actually emits radiation

pravzaprav oddaja sevanje,

when you take into account quantum mechanics.

če upoštevamo kvantno mehaniko.

The curvature of space-time around the black hole

Ukrivljenost prostora-časa okrog črne luknje

brings to life the quantum mechanical fluctuation,

oživi kvantno mehanično fluktuacijo,

and the black hole radiates.

in tako črna luknja seva.

A precisely similar calculation by Hawking and Gary Gibbons

Natančno podoben izračun Hawkinga and Gary Gibbonsa

showed that if you have dark energy in empty space,

je pokazal, da če imamo temno energijo v praznem prostoru,

then the whole universe radiates.

potem celotno vesolje seva.

The energy of empty space

Energija praznega prostora

brings to life quantum fluctuations.

oživi kvantno fluktuacijo.

And so even though the universe will last forever,

Tudi če bo vesolje trajalo večno,

and ordinary matter and radiation will dilute away,

in se bo običajna snov in sevanje redčilo,

there will always be some radiation,

bo vedno ostalo nekaj sevanja,

some thermal fluctuations,

nekaj termične fluktuacije,

even in empty space.

tudi v praznem prostoru.

So what this means

To pomeni,

is that the universe is like a box of gas

da je vesolje kot škatla plina,

that lasts forever.

ki traja večno.

Well what is the implication of that?

In kaj je posledica tega?

That implication was studied by Boltzmann back in the 19th century.

Posledice je proučeval Boltzmann v 19. stoletju.

He said, well, entropy increases

Rekel je, no, entropija narašča

because there are many, many more ways

ker obstaja veliko, veliko več načinov,

for the universe to be high entropy, rather than low entropy.

da je vesolje z visoko entropijo, kot z nizko entropijo.

But that's a probabilistic statement.

Toda to je verjetnostna izjava.

It will probably increase,

Verjetno bo naraščala,

and the probability is enormously huge.

in ta verjetnost je ogromna.

It's not something you have to worry about --

Zagotovo nam ni treba skrbeti,

the air in this room all gathering over one part of the room and suffocating us.

da se ves zrak v tej sobi zbere v eni sami točki in nas tako zaduši.

It's very, very unlikely.

To je zelo, zelo neverjetno.

Except if they locked the doors

Razen, če bi kdo zaklenil vrata

and kept us here literally forever,

in nas zadrževal tu dobesedno za vedno,

that would happen.

bi se to zgodilo.

Everything that is allowed,

Vse kar je dovoljeno,

every configuration that is allowed to be obtained by the molecules in this room,

vsaka postavitev, ki se lahko pripeti molekulam v tej sobi,

would eventually be obtained.

je lahko dosežena pod pravimi pogoji.

So Boltzmann says, look, you could start with a universe

Boltzmann pravi: poglej, lahko začnemo vesolje

that was in thermal equilibrium.

ki je v termičnem ravnovesju.

He didn't know about the Big Bang. He didn't know about the expansion of the universe.

Ni vedel za Veliki Pok. Ni vedel za širjenje vesolja.

He thought that space and time were explained by Isaac Newton --

Mislil je, da sta prostor in čas razložena po Isaacu Newtonu --

they were absolute; they just stuck there forever.

bila sta absolutna in večna.

So his idea of a natural universe

Njegova ideja naravnega vesolja

was one in which the air molecules were just spread out evenly everywhere --

je bila taka, kjer se molekule zraka širijo vsepovsod enakomerno --

the everything molecules.

vse molekule.

But if you're Boltzmann, you know that if you wait long enough,

Toda če ste vi Boltzmann, veste, da če čakaš dovolj časa,

the random fluctuations of those molecules

naključna fluktuacija teh molekul

will occasionally bring them

občasno pripelje molekule

into lower entropy configurations.

v konfiguracije nizke entropije.

And then, of course, in the natural course of things,

In tedaj, seveda, se v naravnem toku,

they will expand back.

ponovno razširijo.

So it's not that entropy must always increase --

Torej ni nujno, da entropija vedno narašča --

you can get fluctuations into lower entropy,

lahko dobimo fluktuacije v nižjo entropijo,

more organized situations.

bolj urejene razmere.

Well if that's true,

Če je to res,

Boltzmann then goes onto invent

Boltzmann izumlja

two very modern-sounding ideas --

dve zelo sodobni ideji --

the multiverse and the anthropic principle.

mnogovesolje in antropično načelo.

He says, the problem with thermal equilibrium

Govori nam, da je problem s termičnim ravnovesjem,

is that we can't live there.

da ne moremo živeti tam.

Remember, life itself depends on the arrow of time.

Pomnite, življenje samo je odvisno od časovnega vektorja.

We would not be able to process information,

Nebi mogli obdelovati informacij,

metabolize, walk and talk,

prebavljati, hoditi in govoriti,

if we lived in thermal equilibrium.

če bi živeli v termičnem ravnovesju.

So if you imagine a very, very big universe,

Tako, če si predstavljate veliko, zelo veliko vesolje,

an infinitely big universe,

neskončno veliko vesolje,

with randomly bumping into each other particles,

z delci, ki se naključno zaletajo eden v drugega,

there will occasionally be small fluctuations in the lower entropy states,

bo prišlo do občasnih majhnih nihanj v nizkem stanju entropije,

and then they relax back.

ki se nato zopet sprostijo.

But there will also be large fluctuations.

Toda prihajalo bo tudi do večjih nihanj.

Occasionally, you will make a planet

Občasno, bo ustvarjen planet

or a star or a galaxy

ali zvezda ali galaksija

or a hundred billion galaxies.

ali sto milijard galaksij.

So Boltzmann says,

Torej Boltzmann govori,

we will only live in the part of the multiverse,

da bomo živeli samo v delu mnogovesolja,

in the part of this infinitely big set of fluctuating particles,

v delu tega neskončnega nabora nihajočih delcev,

where life is possible.

kjer je možno življenje.

That's the region where entropy is low.

To je področje, kjer je entropija nizka.

Maybe our universe is just one of those things

Morda je naše vesolje le ena izmed stvari,

that happens from time to time.

ki se zgodijo občasno.

Now your homework assignment

Zdaj je vaša domača naloga,

is to really think about this, to contemplate what it means.

da razmišljate o tem, kaj to pomeni.

Carl Sagan once famously said

Carl Sagan je nekoč izjavil,

that "in order to make an apple pie,

da "če želimo speči jabolčno pito,

you must first invent the universe."

moramo najprej izumiti vesolje".

But he was not right.

Toda ni imel prav.

In Boltzmann's scenario, if you want to make an apple pie,

Po Boltzmannu, če želimo speči jabolčno pito,

you just wait for the random motion of atoms

le počakamo na naključno gibanje atomov,

to make you an apple pie.

ki nam speče pito.

That will happen much more frequently

To se bo dogajalo bolj pogosto

than the random motions of atoms

kot naključno gibanje atomov,

making you an apple orchard

ki pripelje do sadovnjaka

and some sugar and an oven,

in nekaj sladkorja in pečice,

and then making you an apple pie.

in nam nato speče pito.

So this scenario makes predictions.

Ta scenarij daje napovedi.

And the predictions are

In napovedi so,

that the fluctuations that make us are minimal.

da so nihanja, ki nas ustvarjajo minimalna.

Even if you imagine that this room we are in now

Tudi, če si predstavljate, da ta soba

exists and is real and here we are,

obstaja in je resnična, da smo tukaj,

and we have, not only our memories,

imamo svoje spomine in

but our impression that outside there's something

vtis, da je tam zunaj nekaj

called Caltech and the United States and the Milky Way Galaxy,

imenovanega Caltech in ZDA in galaksija Rimska cesta,

it's much easier for all those impressions to randomly fluctuate into your brain

je enostavnejše, da se vsi ti vtisi naključno zanihajo v vaših možganih,

than for them actually to randomly fluctuate

kot za pravo naključno nihanje

into Caltech, the United States and the galaxy.

v Caltech, ZDA in galaksijo.

The good news is that,

Dobra stvar je,

therefore, this scenario does not work; it is not right.

da ta scenarij ne deluje, ni pravi.

This scenario predicts that we should be a minimal fluctuation.

Ta scenarij predvideva, da smo minimalno nihanje.

Even if you left our galaxy out,

Tudi če izpustimo našo galaksijo,

you would not get a hundred billion other galaxies.

ne bi dobili sto milijard drugih galaksij.

And Feynman also understood this.

In tudi Feynman je razumel to.

Feynman says, "From the hypothesis that the world is a fluctuation,

Feynman govori: "Od hipoteze da je svet nihanje,

all the predictions are that

in vse napoveduje,

if we look at a part of the world we've never seen before,

da če pogledamo del sveta, ki ga še nismo doslej,

we will find it mixed up, and not like the piece we've just looked at --

bo ta zmešan, nič kot predel, ki smo ga gledali --

high entropy.

visoka entropija.

If our order were due to a fluctuation,

Če je naš red zaradi nihanja,

we would not expect order anywhere but where we have just noticed it.

nebi pričakovali reda nikjer drugje razen, kjer smo ga pravkar zaznali.

We therefore conclude the universe is not a fluctuation."

Zatorej zaključujemo, da vesolje ni nihanje".

So that's good. The question is then what is the right answer?

To je dobro. Vprašanje je kaj je pravi odgovor?

If the universe is not a fluctuation,

Če vesolje ni nihanje,

why did the early universe have a low entropy?

zakaj je zgodnje vesolje imelo nizko entropijo?

And I would love to tell you the answer, but I'm running out of time.

In rad bi vam povedal odgovor, a moj čas se izteka.

(Laughter)

(Smeh)

Here is the universe that we tell you about,

Tu je vesolje o katerem govorimo,

versus the universe that really exists.

nasproti vesolji, ki zares obstaja.

I just showed you this picture.

Pravkar sem vam pokazal to sliko.

The universe is expanding for the last 10 billion years or so.

Vesolje se širi že vsaj zadnjih 10 milijard let.

It's cooling off.

Ohlaja se.

But we now know enough about the future of the universe

Toda zdaj vemo dovolj o prihodnosti vesolja,

to say a lot more.

da rečemo veliko več.

If the dark energy remains around,

Če temna energija ostaja okrog,

the stars around us will use up their nuclear fuel, they will stop burning.

bodo zvezde okrog nas porabile svojo jedrsko gorivo in ugasnile.

They will fall into black holes.

Padle bodo v črne luknje.

We will live in a universe

Živeli bomo v vesolju

with nothing in it but black holes.

brez ničesar v njem, razen črnih lukenj.

That universe will last 10 to the 100 years --

To vesolje bo trajalo 10 do 100 let --

a lot longer than our little universe has lived.

veliko dlje, kot je živelo naše malo vesolje.

The future is much longer than the past.

Prihodnost je veliko daljša od preteklosti.

But even black holes don't last forever.

Tudi če črne luknje ne trajajo večno.

They will evaporate,

Bodo izhlapele,

and we will be left with nothing but empty space.

in ostal nam bo le prazen prostor.

That empty space lasts essentially forever.

Tak prazen prostor v bistvu traja večno.

However, you notice, since empty space gives off radiation,

Kakorkoli, če opazite, ker prazen prostor oddaja sevanje,

there's actually thermal fluctuations,

so tam pravzaprav termična nihanja,

and it cycles around

in ciklično prehajajo

all the different possible combinations

vse različne možne kombinacije

of the degrees of freedom that exist in empty space.

stopenj svobode, ki obstajajo v praznem prostoru.

So even though the universe lasts forever,

Tako tudi, če je vesolje večno,

there's only a finite number of things

je le končno mnogo stvari,

that can possibly happen in the universe.

ki se lahko zgodijo v vesolju.

They all happen over a period of time

Vse se zgodijo v časovnem obdobju

equal to 10 to the 10 to the 120 years.

enakem 10 na 10 na 120 let.

So here's two questions for you.

Tu sta dve vprašanji za vas.

Number one: If the universe lasts for 10 to the 10 to the 120 years,

Prvo: Če vesolje traja 10 na 10 na 120 let,

why are we born

zakaj se rodimo

in the first 14 billion years of it,

v prvih 14 milijard let vesolja,

in the warm, comfortable afterglow of the Big Bang?

v toplem, udobnem siju Velikega Poka?

Why aren't we in empty space?

Zakaj nismo v praznem prostoru?

You might say, "Well there's nothing there to be living,"

Lahko rečete: "No, tam ni ničesar za življenje".

but that's not right.

Toda to ni pravilno.

You could be a random fluctuation out of the nothingness.

Lahko bi bili naključno nihanje iz ničesar.

Why aren't you?

Zakaj niste?

More homework assignment for you.

Še nekaj domačih nalog za vas.

So like I said, I don't actually know the answer.

Kot sem rekel, pravzaprav ne vem odgovora.

I'm going to give you my favorite scenario.

Podal vam bom moj najljubši scenarij.

Either it's just like that. There is no explanation.

Bodisi da je tako. Ni razlage.

This is a brute fact about the universe

To je surovo dejstvo o vesolju,

that you should learn to accept and stop asking questions.

ki ga morate spoznati in sprejeti ter nehati postavljati vprašanja.

Or maybe the Big Bang

Ali morda Veliki Pok

is not the beginning of the universe.

ni začetek vesolja.

An egg, an unbroken egg, is a low entropy configuration,

Jajce, ne-razbito jajce, je konfiguracija z nizko entropijo,

and yet, when we open our refrigerator,

in ko odpremo hladilnik

we do not go, "Hah, how surprising to find

ne rečemo, "Ha, kako presenetljivo najti

this low entropy configuration in our refrigerator."

to nizko stopnjo entropije v našem hladilniku".

That's because an egg is not a closed system;

To je ker jajce ni zaprt sistem;

it comes out of a chicken.

pride iz kokoši.

Maybe the universe comes out of a universal chicken.

Morda vesolje pride iz vesoljne kokoši.

Maybe there is something that naturally,

Morda je tam nekaj, kar naravno

through the growth of the laws of physics,

skozi razvoj zakonov fizike,

gives rise to universe like ours

daje porast vesolju, kot je naše

in low entropy configurations.

z nizko entropijo.

If that's true, it would happen more than once;

Če je to res, bi se zgodilo več kot enkrat;

we would be part of a much bigger multiverse.

bi bili del veliko večjega mnogovesolja.

That's my favorite scenario.

To je moj najljubši scenarij.

So the organizers asked me to end with a bold speculation.

Organizatorji so me prosili naj zaključim z drzno špekulacijo.

My bold speculation

Moja drzna špekulacija

is that I will be absolutely vindicated by history.

je da me bo zgodovina popolnoma upravičila.

And 50 years from now,

In čez 50 let,

all of my current wild ideas will be accepted as truths

bodo vse moje trenutno divje ideje sprejete kot resnične

by the scientific and external communities.

tako znanstveniki kot druge skupnosti.

We will all believe that our little universe

Vsi bomo verjeli, da je naše malo vesolje

is just a small part of a much larger multiverse.

le majhen delček veliko večjega mnogovesolja.

And even better, we will understand what happened at the Big Bang

In še več, razumeli bomo kaj se je zgodilo ob Velikem Poku

in terms of a theory

v teoretičnem smislu,

that we will be able to compare to observations.

ker bomo lahko primerjali opazovanja.

This is a prediction. I might be wrong.

To je moja napoved. Lahko se motim.

But we've been thinking as a human race

Toda kot človeštvo razmišljamo

about what the universe was like,

o tem, kakšno je bilo vesolje in

why it came to be in the way it did for many, many years.

zakaj je nastalo in je takšno kot je, že mnogo, mnogo let.

It's exciting to think we may finally know the answer someday.

Razburljivo je, če pomislimo, da bomo morda nekoč le vedeli odgovor.

Thank you.

Hvala vam.

(Applause)

(Aplavz)