There is nothing bigger or older than the universe. The questions I would like to talk about are: one, where did we come from? How did the universe come into being? Are we alone in the universe? Is there alien life out there? What is the future of the human race?
Nič ni večje in starejše od vesolja. Vprašanja, o katerih bi želel govoriti, so: najprej, od kod izviramo? Kako je vesolje nastalo? Smo v vesolju sami? Je tam zunaj tuje življenje? Kakšna je prihodnost človeštva?
Up until the 1920s, everyone thought the universe was essentially static and unchanging in time. Then it was discovered that the universe was expanding. Distant galaxies were moving away from us. This meant they must have been closer together in the past. If we extrapolate back, we find we must have all been on top of each other about 15 billion years ago. This was the Big Bang, the beginning of the universe.
Do 1920-ih so vsi mislili, da je vesolje v bistvu statično in da se s časom ne spreminja. Potem so odkrili, da se vesolje širi. Daljne galaksije se odmikajo od nas. To pomeni, da so nekoč morale biti bolj skupaj. Če zavrtimo čas nazaj, vidimo, da smo morali biti drug vrh drugega pred približno 15 milijardami let. To je bil Veliki pok, začetek vesolja.
But was there anything before the Big Bang? If not, what created the universe? Why did the universe emerge from the Big Bang the way it did? We used to think that the theory of the universe could be divided into two parts. First, there were the laws like Maxwell's equations and general relativity that determined the evolution of the universe, given its state over all of space at one time. And second, there was no question of the initial state of the universe.
Vendar, je bilo kaj pred začetkom Velikega poka? Če ne, kaj je naredilo vesolje? Zakaj se je vesolje pojavilo iz Velikega poka tako, kot je? Menili smo, da teorijo vesolja lahko razdelimo na dva dela. Prvi del, tu so zakoni kot so Maxwellove enačbe in splošna relativnost, ki so določili razvoj vesolja glede na njegovo stanje v vsem prostoru ob določenem času. Drugi del, začetno stanje vesolja, ni bilo vprašanje.
We have made good progress on the first part, and now have the knowledge of the laws of evolution in all but the most extreme conditions. But until recently, we have had little idea about the initial conditions for the universe. However, this division into laws of evolution and initial conditions depends on time and space being separate and distinct. Under extreme conditions, general relativity and quantum theory allow time to behave like another dimension of space. This removes the distinction between time and space, and means the laws of evolution can also determine the initial state. The universe can spontaneously create itself out of nothing.
V prvem delu smo dobro napredovali in zdaj poznamo zakone razvoja v celoti, razen v najbolj ekstremnih pogojih. A do nedavnega smo imeli o začetnih pogojih za vesolje bolj malo zamisli. Vseeno, ta delitev na zakone razvoja in začetne pogoje zavisi od tega, ali sta čas in prostor ločena in različna. V ekstremnih pogojih splošna relativnost in kvantna teorija dopuščata, da se čas obnaša kot še ena razsežnost prostora. To odstrani razliko med časom in prostorom in pomeni, da lahko tudi zakoni razvoja določajo začetno stanje. Vesolje se lahko spontano ustvari iz niča.
Moreover, we can calculate a probability that the universe was created in different states. These predictions are in excellent agreement with observations by the WMAP satellite of the cosmic microwave background, which is an imprint of the very early universe. We think we have solved the mystery of creation. Maybe we should patent the universe and charge everyone royalties for their existence.
Poleg tega lahko izračunamo verjetnosti, ki jih je vesolje ustvarilo v različnih stanjih. Te napovedi se imenitno ujemajo z opazovanji prasevanja, ki je odtis ranega vesolja, s satelitom WMAP. Mislimo, da smo rešili skrivnost stvarjenja. Morda bi morali patentirati vesolje in vsem zaračunavati tantieme za njihov obstoj.
I now turn to the second big question: are we alone, or is there other life in the universe? We believe that life arose spontaneously on the Earth, so it must be possible for life to appear on other suitable planets, of which there seem to be a large number in the galaxy.
Zdaj se obračam k drugemu velikemu vprašanju: smo sami, ali je kje še kakšno življenje v vesolju? Verjamemo, da se je na Zemlji življenje pojavilo spontano, zato mora biti možno, da se življenje pojavlja na drugih primernih planetih, ki jih je, kot kaže, v galaksiji veliko.
But we don't know how life first appeared. We have two pieces of observational evidence on the probability of life appearing. The first is that we have fossils of algae from 3.5 billion years ago. The Earth was formed 4.6 billion years ago and was probably too hot for about the first half billion years. So life appeared on Earth within half a billion years of it being possible, which is short compared to the 10-billion-year lifetime of a planet of Earth type. This suggests that the probability of life appearing is reasonably high. If it was very low, one would have expected it to take most of the ten billion years available.
Vendar ne vemo, kako se je pojavilo prvo življenje. Z opazovanji smo dobili dva dokaza glede verjetnosti, da se življenje pojavi. Prvi je, da imamo fosile alg izpred 3,5 milijarde let. Zemlja se je oblikovala pred 4,6 milijardami let in je bila verjetno prevroča približno prvo polovico milijarde let. Tako se je življenje na Zemlji pojavilo v pol milijarde let takoj, ko se je lahko, kar je malo glede na 10 milijardno življenjsko dobo planeta, kot je Zemlja. To pomeni, da je verjetnost, da se življenje pojavi, dokaj visoka. Če bi bila zelo nizka, bi bilo pričakovati, da bi to potrebovalo večino od 10 milijard let, ki so na voljo.
On the other hand, we don't seem to have been visited by aliens. I am discounting the reports of UFOs. Why would they appear only to cranks and weirdos? If there is a government conspiracy to suppress the reports and keep for itself the scientific knowledge the aliens bring, it seems to have been a singularly ineffective policy so far. Furthermore, despite an extensive search by the SETI project, we haven't heard any alien television quiz shows. This probably indicates that there are no alien civilizations at our stage of development within a radius of a few hundred light years. Issuing an insurance policy against abduction by aliens seems a pretty safe bet.
Po drugi strani kaže, da nas nezemljani niso obiskali. Poročil o NLP ne štejem. Zakaj bi se prikazovali samo usekancem in čudakom? Če pa gre za vladne zarote, da zadržujejo poročila in zase obdržijo znanstvene dosežke, ki jih nezemljani prinašajo, se zdi, da je to bila doslej neverjetno učinkovita politika. Nadalje, kljub obsežnemu iskanju s projektom SETI, nismo slišali še nobenega televizijskega kviza nezemljanov. To najbrž pomeni, da ni nobene tuje civilizacije na naši stopnji razvoja v polmeru nekaj sto svetlobnih let. Izdati zavarovalno polico proti ugrabitvi nezemljanov je videti precej varno.
This brings me to the last of the big questions: the future of the human race. If we are the only intelligent beings in the galaxy, we should make sure we survive and continue. But we are entering an increasingly dangerous period of our history. Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill. But our genetic code still carries the selfish and aggressive instincts that were of survival advantage in the past. It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million.
To me pripelje do zadnjega od velikih vprašanj: prihodnost človeške rase. Če smo edina inteligentna bitja v galaksiji, bi morali zagotoviti, da bomo preživeli in ostali. Pa vstopamo v čedalje bolj nevarno obdobje naše zgodovine. Naše prebivalstvo in naša uporaba omejenih virov planeta Zemlje naraščata eksponentno, skupaj z zmožnostjo naše tehnike, da spremenimo okolje na dobro ali slabo. A naš genetski kod še vedno prenaša sebične in agresivne nagone, ki so bili v preteklosti prednost za preživetje. Dovolj težko bo že v naslednjem stoletju, da se izognemo katastrofi, kaj šele v naslednjih tisoč ali milijon let.
Our only chance of long-term survival is not to remain inward-looking on planet Earth, but to spread out into space. The answers to these big questions show that we have made remarkable progress in the last hundred years. But if we want to continue beyond the next hundred years, our future is in space. That is why I am in favor of manned -- or should I say, personned -- space flight.
Naša edina možnost za dolgoročno preživetje ni, da pozornost usmerjamo noter na planet Zemljo, ampak da se razširimo ven, v vesolje. Odgovori na ta velika vprašanja kažejo, da smo v zadnjih sto letih naredili izjemen napredek. A če želimo ostati tudi po naslednjih sto letih, je naša prihodnost v vesolju. Zato sem za vesoljske polete z moštvi – ali naj raje rečem z osebjem.
All of my life I have sought to understand the universe and find answers to these questions. I have been very lucky that my disability has not been a serious handicap. Indeed, it has probably given me more time than most people to pursue the quest for knowledge. The ultimate goal is a complete theory of the universe, and we are making good progress. Thank you for listening.
Vse svoje življenje sem skušal razumeti vesolje in najti odgovore na ta vprašanja. Imel sem veliko srečo, da me moja prizadetost ni ni resno ovirala. Dejansko mi je verjetno zagotovila več časa, kot večini ljudi, da sem sledil iskanju znanja. Končni cilj je popolna teorija vesolja, in kar dobro napredujemo. Hvala za poslušanje.
Chris Anderson: Professor, if you had to guess either way, do you now believe that it is more likely than not that we are alone in the Milky Way, as a civilization of our level of intelligence or higher? This answer took seven minutes, and really gave me an insight into the incredible act of generosity this whole talk was for TED.
Chris Anderson: Profesor, če bi morali ugibati v katero koli smer, ali zdaj verjamete, da je verjetnost večja, kot ne, da smo v Rimski cesti sami, kot civilizacija na naši ravni inteligence ali višje? Za odgovor je bilo potrebnih sedem minut, kar mi je dalo dober vpogled v to, kako neverjetno velikodušno dejanje za TED je bil ves ta govor.
Stephen Hawking: I think it quite likely that we are the only civilization within several hundred light years; otherwise we would have heard radio waves. The alternative is that civilizations don't last very long, but destroy themselves.
Stephen Hawking: Mislim, da je zelo verjetno, da smo edina civilizacija v območju več sto svetlobnih let; sicer bi slišali radijske valove. Druga možnost je, da civilizacije ne trajajo zelo dolgo, ampak se uničijo.
CA: Professor Hawking, thank you for that answer. We will take it as a salutary warning, I think, for the rest of our conference this week. Professor, we really thank you for the extraordinary effort you made to share your questions with us today. Thank you very much indeed.
CA: Profesor Hawking, hvala za ta odgovor. Vzeli ga bomo, mislim, kot poslovilno opozorilo za preostanek naše konference ta teden. Profesor, res hvala za izreden trud, da ste danes z nami delili vaša vprašanja. Res najlepša hvala.
(Applause)
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