The universe is really big. We live in a galaxy, the Milky Way Galaxy. There are about a hundred billion stars in the Milky Way Galaxy. And if you take a camera and you point it at a random part of the sky, and you just keep the shutter open, as long as your camera is attached to the Hubble Space Telescope, it will see something like this. Every one of these little blobs is a galaxy roughly the size of our Milky Way -- a hundred billion stars in each of those blobs. There are approximately a hundred billion galaxies in the observable universe. 100 billion is the only number you need to know. The age of the universe, between now and the Big Bang, is a hundred billion in dog years. (Laughter) Which tells you something about our place in the universe.
Svemir je jako velik. Živimo u galaksiji Mliječni put. U njoj ima oko sto milijardi zvijezda. Ako uzmete kameru i uperite je u nasumični komad neba, i ostavite zatvarač otvorenim, i ako vam je kamera spojena na teleskop Hubble, vidjet će ovakvo nešto. Svaka mrlja je galaksija veličine Mliječnog puta -- u svakoj oko sto milijardi zvijezda. Postoji oko sto milijardi galaksija u vidljivom svemiru. Sto milijardi je jedini broj. Starost Svemira, od sad do Velikog Praska, je sto milijardi u psećim godinama. (Smijeh) Što vam govori nešto o našem značaju u svemiru.
One thing you can do with a picture like this is simply admire it. It's extremely beautiful. I've often wondered, what is the evolutionary pressure that made our ancestors in the Veldt adapt and evolve to really enjoy pictures of galaxies when they didn't have any. But we would also like to understand it. As a cosmologist, I want to ask, why is the universe like this? One big clue we have is that the universe is changing with time. If you looked at one of these galaxies and measured its velocity, it would be moving away from you. And if you look at a galaxy even farther away, it would be moving away faster. So we say the universe is expanding.
Ovoj slici se divimo. Jako je lijepa. Pitao sam se, kakav evolucijski pritisak je natjerao naše pretke u Veldt ravnicama da evoluiraju da im se sviđaju slike galaksija dok ih nisu imali. Ali ih želimo razumjeti. Kao kozmolog se pitam, zašto je svemir ovakav? Veliki trag je da se svemir mijenja s vremenom. Ako gledate jednu galaksiju, i mjerite joj brzinu, ona se kreće od vas. Ako gledate još dalju galaksiju ona se kreće još brže. Zato kažemo da se svemir širi.
What that means, of course, is that, in the past, things were closer together. In the past, the universe was more dense, and it was also hotter. If you squeeze things together, the temperature goes up. That kind of makes sense to us. The thing that doesn't make sense to us as much is that the universe, at early times, near the Big Bang, was also very, very smooth. You might think that that's not a surprise. The air in this room is very smooth. You might say, "Well, maybe things just smoothed themselves out." But the conditions near the Big Bang are very, very different than the conditions of the air in this room. In particular, things were a lot denser. The gravitational pull of things was a lot stronger near the Big Bang.
To znači da su u prošlosti stvari bile međusobno bliže. U prošlosti je svemir bio gušći, i topliji. Ako nešto stisneš, temperatura raste. To ima smisla. Ono što nema smisla je da je svemir, jako rano, blizu Velikog Praska, bio jako gladak. To nije iznenađujuće. Zrak u ovoj sobi je jako gladak. Kažete, "Možda su se stvari izgladile." Ali uvjeti blizu Velikog Praska su puno drugačiji nego uvjeti zraka u ovoj sobi. Stvari su bile puno gušće. Gravitacijska privlačnost je bila jaka blizu Velikog Praska.
What you have to think about is we have a universe with a hundred billion galaxies, a hundred billion stars each. At early times, those hundred billion galaxies were squeezed into a region about this big -- literally -- at early times. And you have to imagine doing that squeezing without any imperfections, without any little spots where there were a few more atoms than somewhere else. Because if there had been, they would have collapsed under the gravitational pull into a huge black hole. Keeping the universe very, very smooth at early times is not easy; it's a delicate arrangement. It's a clue that the early universe is not chosen randomly. There is something that made it that way. We would like to know what.
Morate znati da imamo svemir sa sto milijardi galaksija, svaka sa sto milijardi zvijeda. U rana vremena, tih sto milijardi galaksija je bilo stješnjeno u ovoliki prostor. Zamislite to stješnjavanje bez ikakvih nesavršenosti, bez ikakvih točkica s više atoma nego drugdje. Jer da je bilo, sve bi se urušilo zbog gravitacije u veliku crnu rupu. Držanje svemira vrlo glatkim tako rano nije lako, to je osjetljiv raspored. To je indicija da rani svemir nije odabran slučajno. Nešto ga je takvim napravilo. Željeli bi znati što.
So part of our understanding of this was given to us by Ludwig Boltzmann, an Austrian physicist in the 19th century. And Boltzmann's contribution was that he helped us understand entropy. You've heard of entropy. It's the randomness, the disorder, the chaoticness of some systems. Boltzmann gave us a formula -- engraved on his tombstone now -- that really quantifies what entropy is. And it's basically just saying that entropy is the number of ways we can rearrange the constituents of a system so that you don't notice, so that macroscopically it looks the same. If you have the air in this room, you don't notice each individual atom. A low entropy configuration is one in which there's only a few arrangements that look that way. A high entropy arrangement is one that there are many arrangements that look that way. This is a crucially important insight because it helps us explain the second law of thermodynamics -- the law that says that entropy increases in the universe, or in some isolated bit of the universe.
Dio shvaćanja ovoga nam je dao Ludwig Boltzmann, Austrijski fizičar 19. stoljeća. Boltzmanov doprinos je bio shvaćanje entropije. Čuli ste za entropiju. To je slučajnost, nered, kaotičnost sistema. Boltzmann nam je dao formulu -- ugraviranu na njegov nadgrobni kamen -- koja kvantificira entropiju. I ona kaže da je entropija suma načina na koji možemo preurediti sustav da se to ne primjeti, da makroskopski izgleda jednako. Imamo zrak u ovoj sobi, ne primjećujete zasebne atome. Kod konfiguracije niske entropije imamo tek nekoliko razmještaja koji izgledaju jednako. Kod visoke entropije imamo puno razmještaja koji izgledaju jednako. Ovo je presudno važan uvid, jer nam objašnjava drugi zakon termodinamike -- zakon koji kaže da se entropija povećava u svemiru, ili u izoliranom dijelu svemira.
The reason why entropy increases is simply because there are many more ways to be high entropy than to be low entropy. That's a wonderful insight, but it leaves something out. This insight that entropy increases, by the way, is what's behind what we call the arrow of time, the difference between the past and the future. Every difference that there is between the past and the future is because entropy is increasing -- the fact that you can remember the past, but not the future. The fact that you are born, and then you live, and then you die, always in that order, that's because entropy is increasing. Boltzmann explained that if you start with low entropy, it's very natural for it to increase because there's more ways to be high entropy. What he didn't explain was why the entropy was ever low in the first place.
Entropija se povećava jer ima puno više načina da budeš visoke nego niske entropije. Ovo je divan uvid, ali nešto izostavlja. Ovo mišljenje da se entropija povećava, stoji iza vremenskog pravca, razlike između prošlosti i budućnosti. Svaka promjena koja postoji između prošlosti i budućnosti jest uslijed povećanja entropije -- činjenica da se možemo sjetiti prošlosti, a ne budućnosti. Činjenica da ste rođeni, pa živite, i onda umrete, uvijek u tom slijedu, jest zbog povećavajuće entropije. Boltzmann je objasnio da ako počnete s malom entropijom, prirodno je da se povećava, jer postoji više načina da bude visoka entropija. Ono što nije objasnio jest zašto je entropija na početku bila niska.
The fact that the entropy of the universe was low was a reflection of the fact that the early universe was very, very smooth. We'd like to understand that. That's our job as cosmologists. Unfortunately, it's actually not a problem that we've been giving enough attention to. It's not one of the first things people would say, if you asked a modern cosmologist, "What are the problems we're trying to address?" One of the people who did understand that this was a problem was Richard Feynman. 50 years ago, he gave a series of a bunch of different lectures. He gave the popular lectures that became "The Character of Physical Law." He gave lectures to Caltech undergrads that became "The Feynman Lectures on Physics." He gave lectures to Caltech graduate students that became "The Feynman Lectures on Gravitation." In every one of these books, every one of these sets of lectures, he emphasized this puzzle: Why did the early universe have such a small entropy?
Ta činjenica ogledava činjenicu da je rani svemir bio gladak. Želimo to razumjeti. To je posao kozmologa. Tom problemu nismo davali dosta pažnje. To nije stvar koju bi prvu rekao da ste pitali kozmologa "Koje probleme pokušavate rješiti?" Jedan od ljudi koji su to razumjeli bio je Richard Feynman. Prije 50 godina, dao je niz predavanja. Popularna predavanja koja su postala "Osobitosti fizikalnih zakona." Davao je predavanja studentima Caltecha koja su postala "Feynmanova predavanja o fizici." Davao je predavanja diplomcima koja su postala "Feynmanova predavanja o gravitaciji." I u svakom predavanju naglašavao je zagonetku: Zašto je rani svemir imao malu entropiju?
So he says -- I'm not going to do the accent -- he says, "For some reason, the universe, at one time, had a very low entropy for its energy content, and since then the entropy has increased. The arrow of time cannot be completely understood until the mystery of the beginnings of the history of the universe are reduced still further from speculation to understanding." So that's our job. We want to know -- this is 50 years ago, "Surely," you're thinking, "we've figured it out by now." It's not true that we've figured it out by now.
Pa kaže -- neću imitirati naglasak -- kaže, "Iz nekog razloga je svemir, imao malu entropiju za istu količinu energije, i entropija se povećavala. Pravac vremena se ne može shvatiti dok se misterij početaka povijesti svemira ne svede s nagađanja na razumjevanje." To je naš posao. To je bilo prije 50 godina, mislite "sigurno smo to već shvatili." Još nismo shvatili.
The reason the problem has gotten worse, rather than better, is because in 1998 we learned something crucial about the universe that we didn't know before. We learned that it's accelerating. The universe is not only expanding. If you look at the galaxy, it's moving away. If you come back a billion years later and look at it again, it will be moving away faster. Individual galaxies are speeding away from us faster and faster so we say the universe is accelerating. Unlike the low entropy of the early universe, even though we don't know the answer for this, we at least have a good theory that can explain it, if that theory is right, and that's the theory of dark energy. It's just the idea that empty space itself has energy.
Razlog zašto se problem još pogoršao je zato što smo 1998. naučili nešto presudno o svemiru. Naučili smo da se ubrzava. Ne samo to. Galaksije se odmiču. Nakon milijardu godina opet pogledaš, odmiču se još brže. Galaksije se odmiču sve brže i brže. Kažemo da se svemir ubrzava. Za razliku od male entropije ranog svemira, makar ne znamo odgovor na to, imamo dobru teoriju koja to objašnjava, ako je točna a to je teorija tamne energije. Kaže da prazan prostor ima energiju.
In every little cubic centimeter of space, whether or not there's stuff, whether or not there's particles, matter, radiation or whatever, there's still energy, even in the space itself. And this energy, according to Einstein, exerts a push on the universe. It is a perpetual impulse that pushes galaxies apart from each other. Because dark energy, unlike matter or radiation, does not dilute away as the universe expands. The amount of energy in each cubic centimeter remains the same, even as the universe gets bigger and bigger. This has crucial implications for what the universe is going to do in the future. For one thing, the universe will expand forever.
U svakom kubičnom centimetru, bilo ili ne bilo stvari, čestica, materije, zračenja, svejedno, ima energije, u samom prostoru. Ova energija, po Einsteinu, vrši guranje na svemir. To je neprekidan impuls koji gura galaksije jednu od druge. Tamna energija se, za razliku od materije ili zračenja, ne razrjeđuje kako se svemir širi. Količina energije u svakom kubičnom centimetru ostaje ista, kako se svemir povećava. Ovo ima presudne implikacije na to što će svemir napraviti u budućnosti. Kao prvo, svemir će se širiti zauvijek.
Back when I was your age, we didn't know what the universe was going to do. Some people thought that the universe would recollapse in the future. Einstein was fond of this idea. But if there's dark energy, and the dark energy does not go away, the universe is just going to keep expanding forever and ever and ever. 14 billion years in the past, 100 billion dog years, but an infinite number of years into the future. Meanwhile, for all intents and purposes, space looks finite to us. Space may be finite or infinite, but because the universe is accelerating, there are parts of it we cannot see and never will see. There's a finite region of space that we have access to, surrounded by a horizon. So even though time goes on forever, space is limited to us. Finally, empty space has a temperature.
Kad sam bio vaših godina, nismo znali što će svemir napraviti. Neki su mislili da će se svemir u budućnosti sažeti. Einsteinu se sviđala ova ideja. Ali ako imamo tamnu energiju, i ona ne odlazi, svemir će se širiti sve više. Prošlih 14 milijardi godina, 100 milijardi psećih godina, i bezbroj godina u budućnost. U međuvremenu, nama, svemir izgleda konačno. Konačan ili beskonačan, pošto se ubrzava, djelove ne možemo vidjeti i nećemo nikad vidjeti. Imamo pristup dijelu svemira, zaokruženog horizontom. Dakle iako vrijeme ide zauvijek, svemir nam je ograničen. Na kraju, prazan svemir ima temperaturu.
In the 1970s, Stephen Hawking told us that a black hole, even though you think it's black, it actually emits radiation when you take into account quantum mechanics. The curvature of space-time around the black hole brings to life the quantum mechanical fluctuation, and the black hole radiates. A precisely similar calculation by Hawking and Gary Gibbons showed that if you have dark energy in empty space, then the whole universe radiates. The energy of empty space brings to life quantum fluctuations. And so even though the universe will last forever, and ordinary matter and radiation will dilute away, there will always be some radiation, some thermal fluctuations, even in empty space. So what this means is that the universe is like a box of gas that lasts forever. Well what is the implication of that?
U 1970-ima, Stephen Hawking je rekao kako crna rupa emitira zračenje, kad uzmete u obzir kvantnu mehaniku. Zakrivljenost vrijeme-prostor oko crne rupe oživljava kvantnomehaničku fluktuaciju, i crna rupa zrači. Sličan račun Hawkinga i Gary Gibbonsa je pokazao da ako imamo tamnu energiju u praznom prostoru, onda cijeli svemir zrači. Energija praznog prostora oživljava kvantne fluktuacije. Dakle iako će svemir trajati vječno, obična materija i zračenje će se razrijediti, uvijek će biti nešto zračenja, nešto termičkih fluktuacija, čak i u praznom prostoru. To znači da je svemir kao kutija plina koja traje zauvijek. Koje su implikacije toga?
That implication was studied by Boltzmann back in the 19th century. He said, well, entropy increases because there are many, many more ways for the universe to be high entropy, rather than low entropy. But that's a probabilistic statement. It will probably increase, and the probability is enormously huge. It's not something you have to worry about -- the air in this room all gathering over one part of the room and suffocating us. It's very, very unlikely. Except if they locked the doors and kept us here literally forever, that would happen. Everything that is allowed, every configuration that is allowed to be obtained by the molecules in this room, would eventually be obtained.
Te implikacije je proučavao Boltzmann još u 19. stoljeću. Rekao je da se entropija povećava jer ima puno više načina za svemir da bude više, nego niže entropije. To je vjerojatnosna izjava. Vjerojatno će se povećati, i vjerojatnost je golema. Ne treba se brinuti da će se zrak u ovoj sobi skupiti na jednu stranu sobe i ugušiti nas. To je vrlo nevjerojatno. Osim ako nas drže ovdje zauvijek, to bi se dogodilo. Sve što je moguće, svaka postava koju je moguće postići molekulama u sobi, će se jednom postići.
So Boltzmann says, look, you could start with a universe that was in thermal equilibrium. He didn't know about the Big Bang. He didn't know about the expansion of the universe. He thought that space and time were explained by Isaac Newton -- they were absolute; they just stuck there forever. So his idea of a natural universe was one in which the air molecules were just spread out evenly everywhere -- the everything molecules. But if you're Boltzmann, you know that if you wait long enough, the random fluctuations of those molecules will occasionally bring them into lower entropy configurations. And then, of course, in the natural course of things, they will expand back. So it's not that entropy must always increase -- you can get fluctuations into lower entropy, more organized situations.
Boltzmann kaže, možeš početi sa svemirom koji je u termičkoj ravnoteži. On nije znao o Velikom Prasku. Nije znao o širenju svemira. Mislio je da je prostor i vrijeme objasnio Isaac Newton -- da su apsolutni; zaglavljeni zauvijek. Njegova ideja o prirodnom svemiru kaže da su molekule zraka raspoređene jednoliko -- molekule svega. Ali Boltzmann zna da ako dovoljno čekaš, slučajne fluktuacije molekula će ih ponekad dovesti u konfiguraciju niske entropije. Tada će se, prirodno, natrag proširiti. Ne treba se entropija uvijek povećavati -- ponekad će fluktuirati u nižu entropiju, organiziraniju situaciju.
Well if that's true, Boltzmann then goes onto invent two very modern-sounding ideas -- the multiverse and the anthropic principle. He says, the problem with thermal equilibrium is that we can't live there. Remember, life itself depends on the arrow of time. We would not be able to process information, metabolize, walk and talk, if we lived in thermal equilibrium. So if you imagine a very, very big universe, an infinitely big universe, with randomly bumping into each other particles, there will occasionally be small fluctuations in the lower entropy states, and then they relax back. But there will also be large fluctuations. Occasionally, you will make a planet or a star or a galaxy or a hundred billion galaxies. So Boltzmann says, we will only live in the part of the multiverse, in the part of this infinitely big set of fluctuating particles, where life is possible. That's the region where entropy is low. Maybe our universe is just one of those things that happens from time to time.
Ako je to istina, Boltzmann nadalje nalazi dvije moderne ideje -- multisvemir i antropički princip. Kaže, problem s termičkom ravnotežom jest da ne omogućuje život. Život ovisi o pravcu vremena. Ne bi mogli procesirati informacije, metabolirati, hodati i pričati, da živimo u termičkoj ravnoteži. Zamislite velik svemir, beskonačno velik sa česticama koje se sudaraju, ponekad će biti malo fluktuacija u stanju niske entropije, i onda se opet smire. Ali bit će i velikih fluktuacija. Ponekad će nastati planet ili zvijezda ili galaksija ili sto milijardi galaksija. Boltzmann kaže, živimo u dijelu multisvemira, u dijelu tog beskonačno velikog seta čestica, gdje je život moguć. To je predio gdje je entropija niska. Možda je naš svemir događaj koji se desi s vremena na vrijeme.
Now your homework assignment is to really think about this, to contemplate what it means. Carl Sagan once famously said that "in order to make an apple pie, you must first invent the universe." But he was not right. In Boltzmann's scenario, if you want to make an apple pie, you just wait for the random motion of atoms to make you an apple pie. That will happen much more frequently than the random motions of atoms making you an apple orchard and some sugar and an oven, and then making you an apple pie. So this scenario makes predictions. And the predictions are that the fluctuations that make us are minimal. Even if you imagine that this room we are in now exists and is real and here we are, and we have, not only our memories, but our impression that outside there's something called Caltech and the United States and the Milky Way Galaxy, it's much easier for all those impressions to randomly fluctuate into your brain than for them actually to randomly fluctuate into Caltech, the United States and the galaxy.
Za zadaću malo razmislite o tome. Carl Sagan je rekao "kako bi napravili pitu od jabuke, prvo morate napraviti svemir." Ali nije bio u pravu. Po Boltzmannu, ako želite napraviti pitu od jabuke, samo čekajte nasumično gibanje atoma da složi pitu od jabuke. To će se dogoditi češće nego da nasumično gibanje atoma napravi voćnjak od jabuka i šećer i pećnicu, i onda vam napravi pitu od jabuke. Taj scenarij predviđa da su fluktuacije koje nas stvaraju minimalne. Ako zamislite da ova soba postoji i stvarna je, i mi smo tu, i imamo, ne samo sjećanje, nego utisak da vani ima nečega kao Caltech i Sjedinjene države i Mliječni put, puno je lakše da ti utisci nasumično fluktuiraju u naš mozak nego da nasumično fluktuiraju u Caltech, Sjedinjene države i galaksiju.
The good news is that, therefore, this scenario does not work; it is not right. This scenario predicts that we should be a minimal fluctuation. Even if you left our galaxy out, you would not get a hundred billion other galaxies. And Feynman also understood this. Feynman says, "From the hypothesis that the world is a fluctuation, all the predictions are that if we look at a part of the world we've never seen before, we will find it mixed up, and not like the piece we've just looked at -- high entropy. If our order were due to a fluctuation, we would not expect order anywhere but where we have just noticed it. We therefore conclude the universe is not a fluctuation." So that's good. The question is then what is the right answer? If the universe is not a fluctuation, why did the early universe have a low entropy? And I would love to tell you the answer, but I'm running out of time.
Dobra je vijest da ovaj scenarij ne radi, nije točan. On predviđa da smo minimalna fluktuacija. I ako dobimo galaksiju, ne bi dobili sto milijardi drugih galaksija. Feynman je to razumio. On kaže, "Od hipoteze da je svijet fluktuacija, svi predviđaju da ako pogledamo dio svijeta koji prije nismo vidjeli, bit će zbrkan i neće biti poput dijela koji smo sada pogledali -- visoka entropija. Da je red tu uslijed fluktuacije, ne bi očekivali red nigdje drugdje. Tako zaključujemo da svemir nije fluktuacija." To je dobro. Ali koji je onda odgovor? Ako svemir nije fluktuacija, zašto je rani svemir imao nisku entropiju? Volio bih vam odgovoriti, ali ponestaje mi vremena.
(Laughter)
(Smijeh)
Here is the universe that we tell you about, versus the universe that really exists. I just showed you this picture. The universe is expanding for the last 10 billion years or so. It's cooling off. But we now know enough about the future of the universe to say a lot more. If the dark energy remains around, the stars around us will use up their nuclear fuel, they will stop burning. They will fall into black holes. We will live in a universe with nothing in it but black holes. That universe will last 10 to the 100 years -- a lot longer than our little universe has lived. The future is much longer than the past. But even black holes don't last forever. They will evaporate, and we will be left with nothing but empty space. That empty space lasts essentially forever. However, you notice, since empty space gives off radiation, there's actually thermal fluctuations, and it cycles around all the different possible combinations of the degrees of freedom that exist in empty space. So even though the universe lasts forever, there's only a finite number of things that can possibly happen in the universe. They all happen over a period of time equal to 10 to the 10 to the 120 years.
Ovo je svemir o kojem vam govorimo, nasuprot svemira koji jest. Pokazao sam ovu sliku. Svemir se širi posljednjih 10 milijardi godina. Hladi se. Ali sad znamo puno više o budućnosti svemira. Ako tamna energija ostane, zvijezde oko nas će iskoristiti svoje gorivo, ugasiti će se. Past će u crne rupe. Živjet ćemo u svemiru s ničim osim crnih rupa. Takav svemir će trajati 10 do 100 godina -- puno duže nego je dosada živio. Budućnost je puno duža od prošlosti. Ni crne rupe ne traju zauvijek. Isparit će, i ostat će nam samo prazan svemir. Taj prazan prostor traje zauvijek. Ali prazan svemir zrači, ima termičke fluktuacije, i vrti se u svim mogućim kombinacijama koje su moguće u praznom svemiru. Iako svemir traje vječno, postoji konačan broj stvari koje se mogu dogoditi u njemu. Sve se dogode u vremenu od 10 na 10 na 120 godina.
So here's two questions for you. Number one: If the universe lasts for 10 to the 10 to the 120 years, why are we born in the first 14 billion years of it, in the warm, comfortable afterglow of the Big Bang? Why aren't we in empty space? You might say, "Well there's nothing there to be living," but that's not right. You could be a random fluctuation out of the nothingness. Why aren't you? More homework assignment for you.
Evo pitanja. Prvo: ako svemir toliko traje, zašto se rađamo u prvih 14 milijardi godina, u toplom rumenilu nakon Velikog Praska? Zašto nismo u praznom svemiru? Reći ćete, "Tamo ništa ne živi," to nije točno. Mogli bi biti nasumična fluktuacija iz ničega. Zašto nismo? Više zadaće za vas.
So like I said, I don't actually know the answer. I'm going to give you my favorite scenario. Either it's just like that. There is no explanation. This is a brute fact about the universe that you should learn to accept and stop asking questions. Or maybe the Big Bang is not the beginning of the universe. An egg, an unbroken egg, is a low entropy configuration, and yet, when we open our refrigerator, we do not go, "Hah, how surprising to find this low entropy configuration in our refrigerator." That's because an egg is not a closed system; it comes out of a chicken. Maybe the universe comes out of a universal chicken. Maybe there is something that naturally, through the growth of the laws of physics, gives rise to universe like ours in low entropy configurations. If that's true, it would happen more than once; we would be part of a much bigger multiverse. That's my favorite scenario.
Ja ne znam odgovor. Ovo je moj najdraži scenarij. Ili je tako, bez objašnjenja. To je činjenica o svemiru koju trebate naučiti. Ili Veliki Prasak nije početak svemira. Nerazbijeno jaje ima malu entropiju, ali kad otvorimo frižider ne kažemo, "Kako iznenađujuće konfiguracija niske entropije u mom frižideru." To je zato što jaje nije zatvoreni sustav; ono dolazi od kokoši. Možda svemir dolazi iz svemirske kokoši. Možda nešto prirodno kroz rast zakona fizike, rađa svemir kao naš u konfiguracijama niske entropije. Ako je to istina, desilo se više puta; i mi smo dio većeg multisvemira. To mi je najdraži scenarij.
So the organizers asked me to end with a bold speculation. My bold speculation is that I will be absolutely vindicated by history. And 50 years from now, all of my current wild ideas will be accepted as truths by the scientific and external communities. We will all believe that our little universe is just a small part of a much larger multiverse. And even better, we will understand what happened at the Big Bang in terms of a theory that we will be able to compare to observations. This is a prediction. I might be wrong. But we've been thinking as a human race about what the universe was like, why it came to be in the way it did for many, many years. It's exciting to think we may finally know the answer someday.
Tražili su me da završim s odvažnom špekulacijom. Ona je da će me povijest opravdati. Za 50 godina sve moje lude ideje će prihvatiti znanstvene zajednice. Svi ćemo vjerovati da je svemir dio većeg multisvemira. Razumjet ćemo što se desilo kod Velikog Praska teorijom koju ćemo moći ispitati. To je predviđanje. Kao ljudska rasa smo razmišljali kakav je svemir, i zašto je ispao ovakav, puno godina. Uzbudljivo je misliti da bi mogli naći odgovor.
Thank you.
Hvala.
(Applause)
(Pljesak)