TEDxCaltech
Sean Carroll: Distant time and the hint of a multiverse
Šon Kerol: Davno vreme i nagoveštaj multiuniverzuma
Filmed:
Readability: 4.2
1,776,253 views
U okviru TEDxCaltech, kosmolog Šon Kerol se hvata u koštac -- na zabavnom i inspirativnom putovanju kroz prirodu vremena i svemira -- sa naizgled jednostavnim pitanjem: zašto vreme uopšte postoji? Mogući odgovori ukazuju na iznenađujući pogled na prirodu svemira i našeg mesta u njemu.
Sean M. Carroll - Physicist, cosmologist
A physicist, cosmologist and gifted science communicator, Sean Carroll is asking himself -- and asking us to consider -- questions that get at the fundamental nature of the universe. Full bio
A physicist, cosmologist and gifted science communicator, Sean Carroll is asking himself -- and asking us to consider -- questions that get at the fundamental nature of the universe. Full bio
Double-click the English transcript below to play the video.
00:15
The universe
0
0
2000
Svemir
00:17
is really big.
1
2000
2000
je zaista ogroman.
00:19
We live in a galaxy, the Milky Way Galaxy.
2
4000
3000
Živimo u galaksiji Mlečni Put
00:22
There are about a hundred billion stars in the Milky Way Galaxy.
3
7000
3000
u kojoj ima oko sto milijardi zvezda.
00:25
And if you take a camera
4
10000
2000
I ako uzmete kameru
00:27
and you point it at a random part of the sky,
5
12000
2000
i uperite je bilo gde ka nebu,
00:29
and you just keep the shutter open,
6
14000
2000
i skinete poklopac,
00:31
as long as your camera is attached to the Hubble Space Telescope,
7
16000
3000
ako vam je kamera priključena na svemirski telskop Habl,
00:34
it will see something like this.
8
19000
2000
videće nešto ovako.
00:36
Every one of these little blobs
9
21000
3000
Svaka od tih malih mrlja
00:39
is a galaxy roughly the size of our Milky Way --
10
24000
2000
je galaksija veličine slične našem Mlečnom putu -
00:41
a hundred billion stars in each of those blobs.
11
26000
3000
sto milijardi zvezda u svakoj od tih mrlja.
00:44
There are approximately a hundred billion galaxies
12
29000
3000
Ima oko sto milijardi galaksija
00:47
in the observable universe.
13
32000
2000
u vidljivom svemiru.
00:49
100 billion is the only number you need to know.
14
34000
2000
Sto milijardi je jedini broj koji treba da znate.
00:51
The age of the universe, between now and the Big Bang,
15
36000
3000
Starost svemira, između Velikog praska i sadašnosti,
00:54
is a hundred billion in dog years.
16
39000
2000
je sto milijardi u psećim godinama.
00:56
(Laughter)
17
41000
2000
(smeh)
00:58
Which tells you something about our place in the universe.
18
43000
3000
Što vam govori nešto o našem mestu u svemiru.
01:01
One thing you can do with a picture like this is simply admire it.
19
46000
2000
Jedino što možete sa ovom slikom jeste da joj se divite.
01:03
It's extremely beautiful.
20
48000
2000
Neverovatno je lepa.
01:05
I've often wondered, what is the evolutionary pressure
21
50000
3000
Često sam se pitao kakav je to pritisak evolucije
01:08
that made our ancestors in the Veldt adapt and evolve
22
53000
3000
terao naše pretke u Africi da se prilagođavaju i evoluiraju
01:11
to really enjoy pictures of galaxies
23
56000
2000
da bi uživali u slikama galaksije
01:13
when they didn't have any.
24
58000
2000
kada ih nisu imali.
01:15
But we would also like to understand it.
25
60000
2000
Ali i mi bismo voleli da razumemo to.
01:17
As a cosmologist, I want to ask, why is the universe like this?
26
62000
4000
Kao kosmolog, želim da se pitam, zašto je svemir ovakav?
01:21
One big clue we have is that the universe is changing with time.
27
66000
3000
Veliki trag koji imamo jeste da se svemir vremenom menja.
01:24
If you looked at one of these galaxies and measured its velocity,
28
69000
3000
Ako pogledate jednu od ovih galaksija i izmerite njenu brzinu,
01:27
it would be moving away from you.
29
72000
2000
ona će se udaljavati od vas.
01:29
And if you look at a galaxy even farther away,
30
74000
2000
A ako pogledate još udaljeniju galaksiju,
01:31
it would be moving away faster.
31
76000
2000
ona će se udaljavati još brže.
01:33
So we say the universe is expanding.
32
78000
2000
Zato kažemo da se svemir širi.
01:35
What that means, of course, is that, in the past,
33
80000
2000
To, naravno, znači da su u prošlosti
01:37
things were closer together.
34
82000
2000
stvari bile skupljenije.
01:39
In the past, the universe was more dense,
35
84000
2000
U prošlosti, svemir je bio gušći
01:41
and it was also hotter.
36
86000
2000
i takođe, topliji.
01:43
If you squeeze things together, the temperature goes up.
37
88000
2000
Ako sabijete stvari zajedno, temperatura raste.
01:45
That kind of makes sense to us.
38
90000
2000
To nam je nekako logično.
01:47
The thing that doesn't make sense to us as much
39
92000
2000
Ono što nije tako logično
01:49
is that the universe, at early times, near the Big Bang,
40
94000
3000
jeste da je svemir, u rano doba, blizu Velikog praska
01:52
was also very, very smooth.
41
97000
2000
takođe bio vrlo vrlo gladak.
01:54
You might think that that's not a surprise.
42
99000
2000
To vas možda ne iznenađuje.
01:56
The air in this room is very smooth.
43
101000
2000
Vazduh u ovoj sobi je vrlo gladak.
01:58
You might say, "Well, maybe things just smoothed themselves out."
44
103000
3000
Mislite, "Pa možda su se stvari same izgladile".
02:01
But the conditions near the Big Bang are very, very different
45
106000
3000
Ali stanja blizu Velikog praska su vrlo različita
02:04
than the conditions of the air in this room.
46
109000
2000
od stanja vazduha u ovoj sobi.
02:06
In particular, things were a lot denser.
47
111000
2000
Tačnije, stvari su bile mnogo gušće.
02:08
The gravitational pull of things
48
113000
2000
Gravitacione sile
02:10
was a lot stronger near the Big Bang.
49
115000
2000
su bile mnogo jače blizu Velikog praska.
02:12
What you have to think about
50
117000
2000
Morate da shvatite
02:14
is we have a universe with a hundred billion galaxies,
51
119000
2000
da svemir ima sto milijardi galaksija,
02:16
a hundred billion stars each.
52
121000
2000
svaka sa po sto milijardi zvezda.
02:18
At early times, those hundred billion galaxies
53
123000
3000
U rano doba, tih sto milijardi galaksija
02:21
were squeezed into a region about this big --
54
126000
3000
je bilo sabijeno u prostor ove veličine --
02:24
literally -- at early times.
55
129000
2000
bukvalno, u rano doba.
02:26
And you have to imagine doing that squeezing
56
131000
2000
I zamislite to sabijanje
02:28
without any imperfections,
57
133000
2000
savršeno izvedeno,
02:30
without any little spots
58
135000
2000
bez nekih malih tačaka
02:32
where there were a few more atoms than somewhere else.
59
137000
2000
gde ima par atoma više nego negde drugde.
02:34
Because if there had been, they would have collapsed under the gravitational pull
60
139000
3000
Da je bilo tako, urušili bi se pod gravitacionim silama
02:37
into a huge black hole.
61
142000
2000
u ogromnu crnu rupu.
02:39
Keeping the universe very, very smooth at early times
62
144000
3000
Održati svemir vrlo glatkim u rano doba
02:42
is not easy; it's a delicate arrangement.
63
147000
2000
je bio vrlo delikatan zadatak.
02:44
It's a clue
64
149000
2000
To je trag
02:46
that the early universe is not chosen randomly.
65
151000
2000
da rani svemir nje bio nasumično odabran.
02:48
There is something that made it that way.
66
153000
2000
Nešto ga je učinilo takvim.
02:50
We would like to know what.
67
155000
2000
Želeli bismo da znamo šta.
02:52
So part of our understanding of this was given to us by Ludwig Boltzmann,
68
157000
3000
Ludvig Boltcman, austrijski fizičar iz 19. veka,
02:55
an Austrian physicist in the 19th century.
69
160000
3000
nam je dao delimično rešenje.
02:58
And Boltzmann's contribution was that he helped us understand entropy.
70
163000
3000
Boltcmanov doprinos je u tome što nam je pomogao da razumemo entropiju.
03:01
You've heard of entropy.
71
166000
2000
Čuli ste za entropiju.
03:03
It's the randomness, the disorder, the chaoticness of some systems.
72
168000
3000
To je nasumičnost, nered, haotičnost nekih sistema.
03:06
Boltzmann gave us a formula --
73
171000
2000
Boltzman nam je dao formulu,
03:08
engraved on his tombstone now --
74
173000
2000
koja je ugravirana na njegovom nadgrobnom spomeniku,
03:10
that really quantifies what entropy is.
75
175000
2000
koja zaista objašnjava entropiju.
03:12
And it's basically just saying
76
177000
2000
I u osnovi nam kaže
03:14
that entropy is the number of ways
77
179000
2000
da je entropija broj načina
03:16
we can rearrange the constituents of a system so that you don't notice,
78
181000
3000
na koji možemo da preuredimo delove sistema, tako da ne primetite,
03:19
so that macroscopically it looks the same.
79
184000
2000
tako da on makroskopski izgleda isto.
03:21
If you have the air in this room,
80
186000
2000
Na primer, vazduh u ovoj sobi,
03:23
you don't notice each individual atom.
81
188000
3000
ne primetite njegov svaki pojedinačni atom.
03:26
A low entropy configuration
82
191000
2000
Sklop sa niskom entropijom
03:28
is one in which there's only a few arrangements that look that way.
83
193000
2000
je onaj gde postoji samo par takvih uređenja.
03:30
A high entropy arrangement
84
195000
2000
Sklop sa visokom entropijom
03:32
is one that there are many arrangements that look that way.
85
197000
2000
je onaj gde postoji veliki broj takvih uređenja.
03:34
This is a crucially important insight
86
199000
2000
To je uvid od ključne važnosti,
03:36
because it helps us explain
87
201000
2000
jer nam pomaže da objasnimo
03:38
the second law of thermodynamics --
88
203000
2000
drugi zakon termodinamike -
03:40
the law that says that entropy increases in the universe,
89
205000
3000
zakon po kome se entropija povećava u svemiru,
03:43
or in some isolated bit of the universe.
90
208000
2000
ili u izolovanom delu svemira.
03:45
The reason why entropy increases
91
210000
2000
Entropija se povećava jer
03:47
is simply because there are many more ways
92
212000
3000
jednostavno ima mnogo više načina
03:50
to be high entropy than to be low entropy.
93
215000
2000
da se postigne visoka nego niska entropija.
03:52
That's a wonderful insight,
94
217000
2000
To je divan uvid,
03:54
but it leaves something out.
95
219000
2000
ali nešto izostavlja.
03:56
This insight that entropy increases, by the way,
96
221000
2000
Usput, uvid da se entropija povećava
03:58
is what's behind what we call the arrow of time,
97
223000
3000
objašnjava ono što nazivamo strelom vremena,
04:01
the difference between the past and the future.
98
226000
2000
razliku između prošlosti i budućnosti.
04:03
Every difference that there is
99
228000
2000
Svaka razlika
04:05
between the past and the future
100
230000
2000
između prošlosti i budućnosti
04:07
is because entropy is increasing --
101
232000
2000
postoji jer se entropija povećava -
04:09
the fact that you can remember the past, but not the future.
102
234000
3000
to što se sećate prošlosti, ali ne i budućnosti.
04:12
The fact that you are born, and then you live, and then you die,
103
237000
3000
To što se rađamo, živimo i umiremo,
04:15
always in that order,
104
240000
2000
uvek tim redom,
04:17
that's because entropy is increasing.
105
242000
2000
je zato što se entropija povećava.
04:19
Boltzmann explained that if you start with low entropy,
106
244000
2000
Boltcman je objasnio da ako se krene od niske entropije,
04:21
it's very natural for it to increase
107
246000
2000
prirodno je da se ona povećava.
04:23
because there's more ways to be high entropy.
108
248000
3000
zato što postoji više načina da se postigne visoka entropija.
04:26
What he didn't explain
109
251000
2000
Ali nije objasnio
04:28
was why the entropy was ever low in the first place.
110
253000
3000
zašto je entropija niska na početku.
04:31
The fact that the entropy of the universe was low
111
256000
2000
To što je entropija svemira bila niska
04:33
was a reflection of the fact
112
258000
2000
odražava činjenicu
04:35
that the early universe was very, very smooth.
113
260000
2000
da je rani svemir bio vrlo, vrlo gladak.
04:37
We'd like to understand that.
114
262000
2000
Hteli bismo to da razumemo.
04:39
That's our job as cosmologists.
115
264000
2000
To je posao nas kosmologa.
04:41
Unfortunately, it's actually not a problem
116
266000
2000
Nažalost, to je problem
04:43
that we've been giving enough attention to.
117
268000
2000
kome smo posvetili malo pažnje.
04:45
It's not one of the first things people would say,
118
270000
2000
On nije jedna od prvih stvari koje biste čuli
04:47
if you asked a modern cosmologist,
119
272000
2000
ako biste pitali savremenog kosmologa,
04:49
"What are the problems we're trying to address?"
120
274000
2000
"Koje probleme pokušavamo da rešimo?"
04:51
One of the people who did understand that this was a problem
121
276000
2000
Jedan od ljudi koji je shvatio da je ovo problem
04:53
was Richard Feynman.
122
278000
2000
je bio Ričard Fejnman.
04:55
50 years ago, he gave a series of a bunch of different lectures.
123
280000
2000
Pre 50 godina, održao je niz različitih predavanja.
04:57
He gave the popular lectures
124
282000
2000
Držao je popularna predavanja
04:59
that became "The Character of Physical Law."
125
284000
2000
koja su postala "Lik fizičkog zakona".
05:01
He gave lectures to Caltech undergrads
126
286000
2000
Držao je predavanja studentima na Kalteku
05:03
that became "The Feynman Lectures on Physics."
127
288000
2000
koja su postala "Fejnmanova predavanja o fizici."
05:05
He gave lectures to Caltech graduate students
128
290000
2000
Držao je predavanja diplomcima na Kalteku
05:07
that became "The Feynman Lectures on Gravitation."
129
292000
2000
koja su postala "Fejnmanova predavanja o gravitaciji"
05:09
In every one of these books, every one of these sets of lectures,
130
294000
3000
U svim tim knjigama, tim nizovima predavanja,
05:12
he emphasized this puzzle:
131
297000
2000
naglašavao je ovu zagonetku:
05:14
Why did the early universe have such a small entropy?
132
299000
3000
zašto je mali svemir imao tako nisku entropiju?
05:17
So he says -- I'm not going to do the accent --
133
302000
2000
I rekao je, neću imitirati akcenat:
05:19
he says, "For some reason, the universe, at one time,
134
304000
3000
"Iz nekog razloga, svemir je u jednom trenutku,
05:22
had a very low entropy for its energy content,
135
307000
3000
imao vrlo nisku entropiju u odnosu na njegovu energiju,
05:25
and since then the entropy has increased.
136
310000
2000
i od tada entropija se uvećala.
05:27
The arrow of time cannot be completely understood
137
312000
3000
Strela vremena se ne može u potpunosti razumeti
05:30
until the mystery of the beginnings of the history of the universe
138
315000
3000
dok se misterija o početku istorijie svemira
05:33
are reduced still further
139
318000
2000
ne svede
05:35
from speculation to understanding."
140
320000
2000
sa nagađanja na razumevanje".
05:37
So that's our job.
141
322000
2000
To je naš posao.
05:39
We want to know -- this is 50 years ago, "Surely," you're thinking,
142
324000
2000
To je bilo pre 50 godina. Vi mislite:
05:41
"we've figured it out by now."
143
326000
2000
"Sigurno smo do sada shvatili."
05:43
It's not true that we've figured it out by now.
144
328000
2000
Nije istina da smo do sada shvatili.
05:45
The reason the problem has gotten worse,
145
330000
2000
Problem je postao i teži,
05:47
rather than better,
146
332000
2000
umesto da postane lakši,
05:49
is because in 1998
147
334000
2000
jer smo 1998. godine
05:51
we learned something crucial about the universe that we didn't know before.
148
336000
3000
saznali nešto ključno o svemiru što nismo znali ranije.
05:54
We learned that it's accelerating.
149
339000
2000
Saznali smo da on ubrzava.
05:56
The universe is not only expanding.
150
341000
2000
Širenje je samo jedna karakteristika svemira.
05:58
If you look at the galaxy, it's moving away.
151
343000
2000
Pogledajte galaksiju i ona će se udaljavati.
06:00
If you come back a billion years later and look at it again,
152
345000
2000
Pogledajte je opet za milijardu godina,
06:02
it will be moving away faster.
153
347000
3000
i udaljavaće se još brže.
06:05
Individual galaxies are speeding away from us faster and faster
154
350000
3000
Pojedine galaksije ubrzavaju od nas sve brže i brže.
06:08
so we say the universe is accelerating.
155
353000
2000
Zato kažemo da svemir ubrzava.
06:10
Unlike the low entropy of the early universe,
156
355000
2000
Za razliku od niske entropije ranog svemira,
06:12
even though we don't know the answer for this,
157
357000
2000
iako ne znamo odgovor na ovo pitanje,
06:14
we at least have a good theory that can explain it,
158
359000
2000
bar imamo dobru teoriju koja ga objašnjava,
06:16
if that theory is right,
159
361000
2000
pod uslovom da je tačna,
06:18
and that's the theory of dark energy.
160
363000
2000
a to je teorija o tamnoj energiji.
06:20
It's just the idea that empty space itself has energy.
161
365000
3000
To je ideja da sam prazan prostor ima energiju.
06:23
In every little cubic centimeter of space,
162
368000
3000
U svakom kubnom centrimetru svemira,
06:26
whether or not there's stuff,
163
371000
2000
bilo da ima nečega ili nema,
06:28
whether or not there's particles, matter, radiation or whatever,
164
373000
2000
bilo da ima čestica, materije, radijacije ili bilo čega,
06:30
there's still energy, even in the space itself.
165
375000
3000
ipak ima energije, čak i u samom prostoru.
06:33
And this energy, according to Einstein,
166
378000
2000
I ta energija, kako Ajnštajn tvrdi,
06:35
exerts a push on the universe.
167
380000
3000
gura svemir.
06:38
It is a perpetual impulse
168
383000
2000
To je trajni impuls
06:40
that pushes galaxies apart from each other.
169
385000
2000
koji je udaljio galksije jednu od druge.
06:42
Because dark energy, unlike matter or radiation,
170
387000
3000
Jer se tamna energija, za razliku materije ili radijacije,
06:45
does not dilute away as the universe expands.
171
390000
3000
ne razređuje kako se svemir širi.
06:48
The amount of energy in each cubic centimeter
172
393000
2000
Količina energije u svakom kubnom centimetru
06:50
remains the same,
173
395000
2000
ostaje ista,
06:52
even as the universe gets bigger and bigger.
174
397000
2000
iako svemir postaje sve veći i veči.
06:54
This has crucial implications
175
399000
3000
Ovo je od bitnog značaja
06:57
for what the universe is going to do in the future.
176
402000
3000
za ono što će svemir raditi ubuduće.
07:00
For one thing, the universe will expand forever.
177
405000
2000
Kao prvo, svemir će se večno širiti.
07:02
Back when I was your age,
178
407000
2000
Kada sam ja bio vaših godina
07:04
we didn't know what the universe was going to do.
179
409000
2000
nismo znali šta će svemir uraditi.
07:06
Some people thought that the universe would recollapse in the future.
180
411000
3000
Neki su mislili da će se svemir urušiti u budućnosti.
07:09
Einstein was fond of this idea.
181
414000
2000
Ajnštajnu se sviđala ta ideja.
07:11
But if there's dark energy, and the dark energy does not go away,
182
416000
3000
Ali ako postoji tamna energija, i ako je trajna,
07:14
the universe is just going to keep expanding forever and ever and ever.
183
419000
3000
svemir će se prosto širiti zauvek i uvek.
07:17
14 billion years in the past,
184
422000
2000
To traje već 14 milijardi godina,
07:19
100 billion dog years,
185
424000
2000
100 milijardi psećih godina,
07:21
but an infinite number of years into the future.
186
426000
3000
ali i beskonačan broj godina u budućnosti.
07:24
Meanwhile, for all intents and purposes,
187
429000
3000
U međuvremenu, za sve namere i svrhe,
07:27
space looks finite to us.
188
432000
2000
svemir nama deluje ograničeno.
07:29
Space may be finite or infinite,
189
434000
2000
Svemir je možda konačan ili beskonačan,
07:31
but because the universe is accelerating,
190
436000
2000
ali pošto ubrzava,
07:33
there are parts of it we cannot see
191
438000
2000
postoje delovi koje ne možemo da vidimo,
07:35
and never will see.
192
440000
2000
i nikada ih nećemo videti.
07:37
There's a finite region of space that we have access to,
193
442000
2000
Imamo pristup ograničenom delu svemira,
07:39
surrounded by a horizon.
194
444000
2000
koji je okružen horizontom.
07:41
So even though time goes on forever,
195
446000
2000
Tako da, iako se vreme večno pruža,
07:43
space is limited to us.
196
448000
2000
svemir je za nas ograničen.
07:45
Finally, empty space has a temperature.
197
450000
3000
Na kraju, prazan svemir ima temperaturu.
07:48
In the 1970s, Stephen Hawking told us
198
453000
2000
Sedamdesetih godina Stiven Hoking nam je rekao,
07:50
that a black hole, even though you think it's black,
199
455000
2000
da crna rupa, iako mislite da je crna,
07:52
it actually emits radiation
200
457000
2000
zapravo emituje radijaciju,
07:54
when you take into account quantum mechanics.
201
459000
2000
kada uzmete u obzir kvantnu mehaniku
07:56
The curvature of space-time around the black hole
202
461000
3000
Zakrivljenost vremena i prostora oko crne rupe,
07:59
brings to life the quantum mechanical fluctuation,
203
464000
3000
stvara fluktuacije kvantne mehanike
08:02
and the black hole radiates.
204
467000
2000
i crna rupa emituje radijaciju.
08:04
A precisely similar calculation by Hawking and Gary Gibbons
205
469000
3000
Jako sličan proračun Hokinga i Garija Gibonsa
08:07
showed that if you have dark energy in empty space,
206
472000
3000
je pokazao, da ako ima tamne energije u praznom prostoru,
08:10
then the whole universe radiates.
207
475000
3000
onda ceo svemir isijava.
08:13
The energy of empty space
208
478000
2000
Energija praznog prostora
08:15
brings to life quantum fluctuations.
209
480000
2000
stvara kvantne fluktuacije.
08:17
And so even though the universe will last forever,
210
482000
2000
I iako će svemir trajati večno,
08:19
and ordinary matter and radiation will dilute away,
211
484000
3000
i obična materija i radijacija će se razrediti,
08:22
there will always be some radiation,
212
487000
2000
uvek će biti neke radijacije,
08:24
some thermal fluctuations,
213
489000
2000
nekih termalnih fluktuacija,
08:26
even in empty space.
214
491000
2000
čak i u praznom prostoru.
08:28
So what this means
215
493000
2000
Dakle to znači
08:30
is that the universe is like a box of gas
216
495000
2000
da je svemir kao kutija gasa
08:32
that lasts forever.
217
497000
2000
koja večno traje.
08:34
Well what is the implication of that?
218
499000
2000
Dakle šta to implicira?
08:36
That implication was studied by Boltzmann back in the 19th century.
219
501000
3000
Implikacije je proučavao Boltcman u 19. veku.
08:39
He said, well, entropy increases
220
504000
3000
Rekao je da se entropija povećava
08:42
because there are many, many more ways
221
507000
2000
jer postoji mnogo više načina
08:44
for the universe to be high entropy, rather than low entropy.
222
509000
3000
da svemir ima visoku neko nisku entropiju.
08:47
But that's a probabilistic statement.
223
512000
3000
Ali to je izjava o verovatnoći.
08:50
It will probably increase,
224
515000
2000
Verovatno će se povećati,
08:52
and the probability is enormously huge.
225
517000
2000
i verovatnoća je ogromna.
08:54
It's not something you have to worry about --
226
519000
2000
O tome ne brinite -
08:56
the air in this room all gathering over one part of the room and suffocating us.
227
521000
4000
da će se vazduh u sobi skupiti u jednom delu i ugušiti nas.
09:00
It's very, very unlikely.
228
525000
2000
To je vrlo malo verovatno.
09:02
Except if they locked the doors
229
527000
2000
Osim ako bi zaključali vrata
09:04
and kept us here literally forever,
230
529000
2000
i držali nas ovde bukvalno zauvek,
09:06
that would happen.
231
531000
2000
to bi se desilo.
09:08
Everything that is allowed,
232
533000
2000
Sve što je moguće
09:10
every configuration that is allowed to be obtained by the molecules in this room,
233
535000
3000
svaki mogući sklop molekula u ovoj sobi,
09:13
would eventually be obtained.
234
538000
2000
će se vremenom ostvariti.
09:15
So Boltzmann says, look, you could start with a universe
235
540000
3000
Bolcman je rekao, počnimo od svemira
09:18
that was in thermal equilibrium.
236
543000
2000
koji je bio u termalnoj ravnoteži.
09:20
He didn't know about the Big Bang. He didn't know about the expansion of the universe.
237
545000
3000
Nije znao za Veliki prasak i širenje svemira.
09:23
He thought that space and time were explained by Isaac Newton --
238
548000
3000
Mislio je da je Njutn objasnio prostor i vreme -
09:26
they were absolute; they just stuck there forever.
239
551000
2000
da su apsolutni; da jednostavno postoje večno.
09:28
So his idea of a natural universe
240
553000
2000
Njegova ideja o prirodnom svemiru
09:30
was one in which the air molecules were just spread out evenly everywhere --
241
555000
3000
je ona gde su molekuli vazduha jednako raspoređeni svuda -
09:33
the everything molecules.
242
558000
2000
molekuli svega.
09:35
But if you're Boltzmann, you know that if you wait long enough,
243
560000
3000
Ali ako ste Bolcman, znate da ako dovoljno čekate,
09:38
the random fluctuations of those molecules
244
563000
3000
nasumične fluktuacije tih molekula
09:41
will occasionally bring them
245
566000
2000
će ih povremeno dovesti
09:43
into lower entropy configurations.
246
568000
2000
u sklopove sa niskom entropijom.
09:45
And then, of course, in the natural course of things,
247
570000
2000
I naravno, po prirodnom toku,
09:47
they will expand back.
248
572000
2000
oni će se ponovo raširiti.
09:49
So it's not that entropy must always increase --
249
574000
2000
Nije da se entropija mora uvek uvećavati -
09:51
you can get fluctuations into lower entropy,
250
576000
3000
fluktuacije mogu imati nižu entropiju,
09:54
more organized situations.
251
579000
2000
organizovanije situacije.
09:56
Well if that's true,
252
581000
2000
Ako je to tačno,
09:58
Boltzmann then goes onto invent
253
583000
2000
Bolcman je onda izmislio
10:00
two very modern-sounding ideas --
254
585000
2000
dve vrlo savremene ideje -
10:02
the multiverse and the anthropic principle.
255
587000
3000
multiverzum i antropički princip.
10:05
He says, the problem with thermal equilibrium
256
590000
2000
On kaže da je problem sa termalnom ravnotežom
10:07
is that we can't live there.
257
592000
2000
što mi ne možemo da živimo u njoj.
10:09
Remember, life itself depends on the arrow of time.
258
594000
3000
Sećate se, sam život zavisi od strele vremena.
10:12
We would not be able to process information,
259
597000
2000
Ne bismo mogli da obrađujemo informacije,
10:14
metabolize, walk and talk,
260
599000
2000
razvijamo se, hodamo i pričamo,
10:16
if we lived in thermal equilibrium.
261
601000
2000
da živimo u termalnoj ravnoteži.
10:18
So if you imagine a very, very big universe,
262
603000
2000
Ako zamislite veoma veliki svemir,
10:20
an infinitely big universe,
263
605000
2000
beskonačno veliki svemir,
10:22
with randomly bumping into each other particles,
264
607000
2000
sa česticama koje nasumično naleću jedna na drugu,
10:24
there will occasionally be small fluctuations in the lower entropy states,
265
609000
3000
povremeno će biti malih fluktuacija u stanjima sa niskom entropijom
10:27
and then they relax back.
266
612000
2000
koje će se onda ponovo opustiti.
10:29
But there will also be large fluctuations.
267
614000
2000
Ali će takođe biti velikih fluktuacija.
10:31
Occasionally, you will make a planet
268
616000
2000
Povremeno, nastaće planeta
10:33
or a star or a galaxy
269
618000
2000
ili zvezda ili galaksija
10:35
or a hundred billion galaxies.
270
620000
2000
ili sto milijardi galaksija.
10:37
So Boltzmann says,
271
622000
2000
I Bolcman kaže,
10:39
we will only live in the part of the multiverse,
272
624000
3000
živećemo samo u delu multiverzuma,
10:42
in the part of this infinitely big set of fluctuating particles,
273
627000
3000
u delu tog beskonačno velikog skupa fluktuacija čestica
10:45
where life is possible.
274
630000
2000
gde je život moguć.
10:47
That's the region where entropy is low.
275
632000
2000
To je deo gde je entropija niska.
10:49
Maybe our universe is just one of those things
276
634000
3000
Možda je naš svemir samo jedna od onih stvari
10:52
that happens from time to time.
277
637000
2000
koje se dešavaju s vremena na vreme.
10:54
Now your homework assignment
278
639000
2000
Vaš domaći zadatak
10:56
is to really think about this, to contemplate what it means.
279
641000
2000
je da dobro razmislite o ovome i šta to znači.
10:58
Carl Sagan once famously said
280
643000
2000
Karl Sagan je jednom rekao,
11:00
that "in order to make an apple pie,
281
645000
2000
"da biste napravili pitu sa jabukama,"
11:02
you must first invent the universe."
282
647000
3000
prvo morate izumiti svemir".
11:05
But he was not right.
283
650000
2000
Ali nije bio u pravu.
11:07
In Boltzmann's scenario, if you want to make an apple pie,
284
652000
3000
Po Bolcmanovom scenariju, ako hoćete da napravite pitu sa jabukama,
11:10
you just wait for the random motion of atoms
285
655000
3000
samo čekate nasumično kretanje atoma
11:13
to make you an apple pie.
286
658000
2000
da vam napravi pitu.
11:15
That will happen much more frequently
287
660000
2000
To će se desiti mnogo češće
11:17
than the random motions of atoms
288
662000
2000
nego da vam nasumično kretanje atoma
11:19
making you an apple orchard
289
664000
2000
napravi voćnjak jabuka
11:21
and some sugar and an oven,
290
666000
2000
i malo šećera i pećnicu
11:23
and then making you an apple pie.
291
668000
2000
i onda vam napravi pitu.
11:25
So this scenario makes predictions.
292
670000
3000
Dakle ovaj scenario pravi predviđanja.
11:28
And the predictions are
293
673000
2000
A, ona kažu
11:30
that the fluctuations that make us are minimal.
294
675000
3000
da su fluktuacije koje nas sačinjavaju minimalne.
11:33
Even if you imagine that this room we are in now
295
678000
3000
Čak i ako zamislite da soba u kojoj smo sada
11:36
exists and is real and here we are,
296
681000
2000
postoji i da je stvarna i da smo tu,
11:38
and we have, not only our memories,
297
683000
2000
i imamo ne samo naša sećanja,
11:40
but our impression that outside there's something
298
685000
2000
već i utisak da napolju postoji nešto
11:42
called Caltech and the United States and the Milky Way Galaxy,
299
687000
4000
zvano Kaltek i Sjedinjene Države i Mlečni Put,
11:46
it's much easier for all those impressions to randomly fluctuate into your brain
300
691000
3000
mnogo je lakše da ti utisci nasumično fluktuiraju u vaš mozak
11:49
than for them actually to randomly fluctuate
301
694000
2000
nego da zapravo nasumično fluktuiraju
11:51
into Caltech, the United States and the galaxy.
302
696000
3000
u Kaltek, Sjedinjene Države i galaksiju.
11:54
The good news is that,
303
699000
2000
Dobra vest je
11:56
therefore, this scenario does not work; it is not right.
304
701000
3000
da, stoga, ovaj scenario ne radi, nije tačan.
11:59
This scenario predicts that we should be a minimal fluctuation.
305
704000
3000
Ovaj scenario predviđa da bismo trebali da budemo minimalne fluktuacije.
12:02
Even if you left our galaxy out,
306
707000
2000
Čak i ako izostavite našu galaksiju,
12:04
you would not get a hundred billion other galaxies.
307
709000
2000
nećete dobiti sto milijardi drugih galaksija.
12:06
And Feynman also understood this.
308
711000
2000
A, Fejnman je razumeo i ovo.
12:08
Feynman says, "From the hypothesis that the world is a fluctuation,
309
713000
4000
Rekao je, "Od pretpostavke da je svet fluktuacija,
12:12
all the predictions are that
310
717000
2000
sva predviđanja govore,
12:14
if we look at a part of the world we've never seen before,
311
719000
2000
da ako pogledamo deo sveta koji nismo ranije videli,
12:16
we will find it mixed up, and not like the piece we've just looked at --
312
721000
2000
on će biti pomešan, a ne kao deo koji smo upravo videli -
12:18
high entropy.
313
723000
2000
visoka entropija.
12:20
If our order were due to a fluctuation,
314
725000
2000
Ako je naš red posledica fluktuacije,
12:22
we would not expect order anywhere but where we have just noticed it.
315
727000
2000
očekivali bismo red samo tamo gde smo ga već primetili.
12:24
We therefore conclude the universe is not a fluctuation."
316
729000
4000
Dakle zaključujemo da svemir nije fluktuacija".
12:28
So that's good. The question is then what is the right answer?
317
733000
3000
To je dobro. Pitanje je onda šta je pravi odgovor?
12:31
If the universe is not a fluctuation,
318
736000
2000
Ako svemir nije fluktuacija,
12:33
why did the early universe have a low entropy?
319
738000
3000
zašto je rani svemir imao nisku entropiju?
12:36
And I would love to tell you the answer, but I'm running out of time.
320
741000
3000
I voleo bih da vam kažem odgovor, ali nestaje mi vremena.
12:39
(Laughter)
321
744000
2000
(smeh)
12:41
Here is the universe that we tell you about,
322
746000
2000
Ovo je svemir o kojem vam mi pričamo,
12:43
versus the universe that really exists.
323
748000
2000
nasuprot svemiru koji zaista postoji.
12:45
I just showed you this picture.
324
750000
2000
Upravo sam vam pokazao ovu sliku.
12:47
The universe is expanding for the last 10 billion years or so.
325
752000
2000
Svemir se širi otprilike proteklilh 10 milijardi godina
12:49
It's cooling off.
326
754000
2000
Hladi se.
12:51
But we now know enough about the future of the universe
327
756000
2000
Ali znamo dovoljno o budućnosti svemira
12:53
to say a lot more.
328
758000
2000
da bismo rekli mnogo više.
12:55
If the dark energy remains around,
329
760000
2000
Ako tamna energija ostaje prisutna,
12:57
the stars around us will use up their nuclear fuel, they will stop burning.
330
762000
3000
zvezde oko nas će potrošiti svoje nuklearno gorivo i ugasiće se.
13:00
They will fall into black holes.
331
765000
2000
Urušiće se u crne rupe.
13:02
We will live in a universe
332
767000
2000
Živećemo u svemiru
13:04
with nothing in it but black holes.
333
769000
2000
u kojem postoje smao crne rupe.
13:06
That universe will last 10 to the 100 years --
334
771000
4000
Taj svemir će trajati 10 na 100-ti godina -
13:10
a lot longer than our little universe has lived.
335
775000
2000
mnogo duže od našeg malog svemira.
13:12
The future is much longer than the past.
336
777000
2000
Budućnost je mnogo duža od prošlosti.
13:14
But even black holes don't last forever.
337
779000
2000
Ali čak ni crne rupe ne traju večno.
13:16
They will evaporate,
338
781000
2000
One će ispariti
13:18
and we will be left with nothing but empty space.
339
783000
2000
i ostaće samo prazan prostor.
13:20
That empty space lasts essentially forever.
340
785000
4000
Taj prazan prostor u suštini traje večno.
13:24
However, you notice, since empty space gives off radiation,
341
789000
3000
Ipak, primetićete, pošto prazan prostor emituje radijaciju,
13:27
there's actually thermal fluctuations,
342
792000
2000
zapravo postoje termalne fluktuacije,
13:29
and it cycles around
343
794000
2000
i ciklus se ponavalja;
13:31
all the different possible combinations
344
796000
2000
sve moguće različite kombinacije
13:33
of the degrees of freedom that exist in empty space.
345
798000
3000
stepena slobode koji postoje u praznom prostoru.
13:36
So even though the universe lasts forever,
346
801000
2000
Dakle, iako svemir traje večno,
13:38
there's only a finite number of things
347
803000
2000
postoji samo ograničen broj stvari
13:40
that can possibly happen in the universe.
348
805000
2000
koje mogu da se dese u njemu.
13:42
They all happen over a period of time
349
807000
2000
Sve se dešavaju tokom vremenskog perioda
13:44
equal to 10 to the 10 to the 120 years.
350
809000
3000
koji iznosi 10 na 10-ti na 120-ti godina.
13:47
So here's two questions for you.
351
812000
2000
Dakle, evo dva pitanja za vas.
13:49
Number one: If the universe lasts for 10 to the 10 to the 120 years,
352
814000
3000
Prvo: ako svemir traje 10 na 10-ti na 120-ti godina,
13:52
why are we born
353
817000
2000
zašto se rađamo
13:54
in the first 14 billion years of it,
354
819000
3000
u njegovih prvih 14 milijardi godina,
13:57
in the warm, comfortable afterglow of the Big Bang?
355
822000
3000
u toplom, prijatnom odsjaju Velikog praska?
14:00
Why aren't we in empty space?
356
825000
2000
Zašto nismo u praznom prostoru?
14:02
You might say, "Well there's nothing there to be living,"
357
827000
2000
Možda kažete, "Pa tamo ništa ne može da živi",
14:04
but that's not right.
358
829000
2000
ali to nije tačno.
14:06
You could be a random fluctuation out of the nothingness.
359
831000
2000
Možete biti nasumična fluktuacija iz ništavila.
14:08
Why aren't you?
360
833000
2000
Zašto niste?
14:10
More homework assignment for you.
361
835000
3000
Eto vam još domaćeg zadatka.
14:13
So like I said, I don't actually know the answer.
362
838000
2000
Kao što rekoh, ja zapravo ne znam odgovor.
14:15
I'm going to give you my favorite scenario.
363
840000
2000
Daću vam moj omiljeni scenario.
14:17
Either it's just like that. There is no explanation.
364
842000
3000
Ili je to tek tako. Ne postoji objašnjenje.
14:20
This is a brute fact about the universe
365
845000
2000
To je okrutna činjenica o svemiru
14:22
that you should learn to accept and stop asking questions.
366
847000
3000
koju treba da prihvatite i ne postavljate pitanja.
14:26
Or maybe the Big Bang
367
851000
2000
Ili možda Veliki prasak
14:28
is not the beginning of the universe.
368
853000
2000
nije početak svemira.
14:30
An egg, an unbroken egg, is a low entropy configuration,
369
855000
3000
Jaje, nepolomljeno jaje, je sklop niske entropije,
14:33
and yet, when we open our refrigerator,
370
858000
2000
a ipak, kada otvorimo frižider,
14:35
we do not go, "Hah, how surprising to find
371
860000
2000
ne pomislimo, "Kako je čudno da se nađe
14:37
this low entropy configuration in our refrigerator."
372
862000
2000
ovaj sklop sa niskom entropijom u mom frižideru".
14:39
That's because an egg is not a closed system;
373
864000
3000
To je zato što jaje nije zatvoren sistem;
14:42
it comes out of a chicken.
374
867000
2000
nastaje iz kokoške.
14:44
Maybe the universe comes out of a universal chicken.
375
869000
4000
Možda svemir nastaje iz svemirske kokoške.
14:48
Maybe there is something that naturally,
376
873000
2000
Možda postoji nešto što prirodnim putem,
14:50
through the growth of the laws of physics,
377
875000
3000
kroz rast zakona fizike,
14:53
gives rise to universe like ours
378
878000
2000
stvara svemir poput našeg
14:55
in low entropy configurations.
379
880000
2000
u sklopovima niske entropije.
14:57
If that's true, it would happen more than once;
380
882000
2000
Ako je to tačno, desilo bi se više puta;
14:59
we would be part of a much bigger multiverse.
381
884000
3000
bili bismo deo mnogo većeg multiverzuma.
15:02
That's my favorite scenario.
382
887000
2000
To je moj omiljeni scenario.
15:04
So the organizers asked me to end with a bold speculation.
383
889000
3000
Organizatori su me zamolili da završim sa hrabrim nagađanjem.
15:07
My bold speculation
384
892000
2000
Moje hrabro nagađanje
15:09
is that I will be absolutely vindicated by history.
385
894000
3000
je da će me istorija potpuno opravdati.
15:12
And 50 years from now,
386
897000
2000
I da će za 50 godina,
15:14
all of my current wild ideas will be accepted as truths
387
899000
3000
sve moje lude ideje biti prihvaćene kao istine
15:17
by the scientific and external communities.
388
902000
3000
od strane naučnih i ostalih udruženja.
15:20
We will all believe that our little universe
389
905000
2000
Svi ćemo verovati da je naš mali svemir
15:22
is just a small part of a much larger multiverse.
390
907000
3000
samo mali deo mnogo većeg multiverzuma.
15:25
And even better, we will understand what happened at the Big Bang
391
910000
3000
I još bolje, razumećemo se šta se desilo sa Velikim praskom
15:28
in terms of a theory
392
913000
2000
u pogledu teorije
15:30
that we will be able to compare to observations.
393
915000
2000
koju ćemo moći da poredimo sa opažanjima.
15:32
This is a prediction. I might be wrong.
394
917000
2000
To je predviđanje. Možda grešim.
15:34
But we've been thinking as a human race
395
919000
2000
Ali razmišljali smo kao ljudska rasa
15:36
about what the universe was like,
396
921000
2000
o tome kakav je bio svemir,
15:38
why it came to be in the way it did for many, many years.
397
923000
3000
zašto je postao i ostao kakav jeste tokom mnogo, mnogo godina.
15:41
It's exciting to think we may finally know the answer someday.
398
926000
3000
Uzbudljivo je pomisliti da ćemo jednom konačno saznati odgovor.
15:44
Thank you.
399
929000
2000
Hvala vam.
15:46
(Applause)
400
931000
2000
(aplauz)
ABOUT THE SPEAKER
Sean M. Carroll - Physicist, cosmologistA physicist, cosmologist and gifted science communicator, Sean Carroll is asking himself -- and asking us to consider -- questions that get at the fundamental nature of the universe.
Why you should listen
Sean Carroll is a theoretical physicist at Caltech in Pasadena, California, where he researches theoretical aspects of cosmology, field theory and gravitation -- exploring the nature of fundamental physics by studying the structure and evolution of the universe.
His book on cosmology and the arrow of time, From Eternity to Here: The Quest for the Ultimate Theory of Time, was published in 2010. He keeps a regular blog at Cosmic Variance.
Sean M. Carroll | Speaker | TED.com