TED2008
Patricia Burchat: Shedding light on dark matter
Patriša Burčet rasvetljava tamnu materiju
Filmed:
Readability: 4.2
1,605,112 views
Fizičar Patriša Burčet rasvetljava dva osnovna sastojka našeg univerzuma: tamnu materiju i tamnu energiju. Oni zajedno čine 96% univerzuma, ne mogu se direktno meriti, ali je njihov uticaj ogroman.
Patricia Burchat - Particle physicist
Patricia Burchat studies the structure and distribution of dark matter and dark energy. These mysterious ingredients can't be measured in conventional ways, yet form a quarter of the mass of our universe. Full bio
Patricia Burchat studies the structure and distribution of dark matter and dark energy. These mysterious ingredients can't be measured in conventional ways, yet form a quarter of the mass of our universe. Full bio
Double-click the English transcript below to play the video.
00:18
As a particle physicist, I study the elementary particles
0
0
4000
Kao fizičar čestica, ja proučavam elementarne čestice
00:22
and how they interact on the most fundamental level.
1
4000
3000
i kako one međusobno reaguju na najosnovnijem nivou.
00:25
For most of my research career, I've been using accelerators,
2
7000
3000
Veći deo svoje istraživačke karijere koristim akceleratore,
00:28
such as the electron accelerator at Stanford University, just up the road,
3
10000
3000
kao što je akcelerator elektrona na Univerzitetu Stanford, ovde blizu,
00:31
to study things on the smallest scale.
4
13000
3000
kako bi proučavala stvari na najmanjoj skali.
00:34
But more recently, I've been turning my attention
5
16000
2000
Ali od nedavno, počela sam da se bavim
00:36
to the universe on the largest scale.
6
18000
3000
univerzumom na najvećoj skali.
00:39
Because, as I'll explain to you,
7
21000
2000
Pošto su, kako ću vam objasniti,
00:41
the questions on the smallest and the largest scale are actually very connected.
8
23000
4000
pitanja na najmanjoj i najvećoj skali zapravo veoma povezana.
00:45
So I'm going to tell you about our twenty-first-century view of the universe,
9
27000
5000
Znači pričaću vam o našem viđenju univerzuma u 21. veku,
00:50
what it's made of and what the big questions in the physical sciences are --
10
32000
3000
od čega se sastoji i koja su velika pitanja fizičkih nauka --
00:53
at least some of the big questions.
11
35000
2000
barem neka od velikih pitanja.
00:55
So, recently, we have realized
12
37000
3000
Nedavno smo shvatili
00:58
that the ordinary matter in the universe --
13
40000
2000
da obična materija u univerzumu --
01:00
and by ordinary matter, I mean you, me,
14
42000
3000
i kada kažem obična materija mislim na vas, OK, mene,
01:03
the planets, the stars, the galaxies --
15
45000
2000
planete, zvezde, galaksije --
01:05
the ordinary matter makes up only a few percent
16
47000
3000
obična materija koja čini samo nekoliko procenata
01:08
of the content of the universe.
17
50000
2000
sastava univerzuma.
01:10
Almost a quarter, or approximately a quarter
18
52000
3000
Skoro četvrtina, ili otprilike četvrtina
01:13
of the matter in the universe, is stuff that's invisible.
19
55000
3000
materije u univerzumu, je ono što je nevidljivo.
01:16
By invisible, I mean it doesn't absorb in the electromagnetic spectrum.
20
58000
4000
Kada kažem nevidljivo mislim da ne apsorbuje elektromagnetni spektar.
01:20
It doesn't emit in the electromagnetic spectrum. It doesn't reflect.
21
62000
3000
Ne emituje u elektromagnetni spektar. Ne reflektuje.
01:23
It doesn't interact with the electromagnetic spectrum,
22
65000
2000
Nema interakciju sa elektromagnetnim spektrom,
01:25
which is what we use to detect things.
23
67000
2000
koga koristimo za detekciju stvari.
01:27
It doesn't interact at all. So how do we know it's there?
24
69000
3000
Uopšte nema interakcije. Pa kako onda znamo da je tu?
01:30
We know it's there by its gravitational effects.
25
72000
2000
Znamo da je tu zbog njegovog gravitacionog dejstva.
01:32
In fact, this dark matter dominates
26
74000
3000
Zapravo, ova tamna materija dominira
01:35
the gravitational effects in the universe on a large scale,
27
77000
3000
gravitacionim efektima u univerzumu na velikoj skali,
01:38
and I'll be telling you about the evidence for that.
28
80000
2000
i govoriću vam o dokazima za to.
01:40
What about the rest of the pie?
29
82000
2000
A šta je sa ostatkom kruga?
01:42
The rest of the pie is a very mysterious substance called dark energy.
30
84000
4000
Ostatak kruga je veoma misteriozna supstanca nazvana tamna energija.
01:46
More about that later, OK.
31
88000
2000
Više o tome kasnije, OK.
01:48
So for now, let's turn to the evidence for dark matter.
32
90000
3000
Za sada, hajde da se okrenemo dokazima za tamnu materiju.
01:51
In these galaxies, especially in a spiral galaxy like this,
33
93000
3000
U ovim galaksijama, posebno u spiralnoj galaksiji poput ove,
01:54
most of the mass of the stars is concentrated in the middle of the galaxy.
34
96000
5000
većina mase zvezda je koncentrisana u sredini galaksije.
01:59
This huge mass of all these stars keeps stars in circular orbits in the galaxy.
35
101000
7000
Ova ogromna masa svih ovih zvezda drži zvezde u kružnim orbitama u galaksiji.
02:06
So we have these stars going around in circles like this.
36
108000
3000
Znači imamo ove zvezde koje kruže ovako.
02:09
As you can imagine, even if you know physics, this should be intuitive, OK --
37
111000
4000
Kao što pretpostavljate, čak iako znate fiziku --ovo treba da je intuitivno, OK --
02:13
that stars that are closer to the mass in the middle will be rotating at a higher speed
38
115000
6000
da će se zvezde koje su bliže masi u sredini rotirati većom brzinom
02:19
than those that are further out here, OK.
39
121000
3000
od onih koje su udaljenije, OK.
02:22
So what you would expect is that if you measured the orbital speed of the stars,
40
124000
5000
Ono što biste očekivali jeste da ako biste merili orbitalnu brzinu zvezda,
02:27
that they should be slower on the edges than on the inside.
41
129000
4000
one bi trebalo da budu sporije na ivicama nego unutra.
02:31
In other words, if we measured speed as a function of distance --
42
133000
2000
Drugim rečima, ako bi merili brzinu kao funkciju rastojanja --
02:33
this is the only time I'm going to show a graph, OK --
43
135000
2000
ovo je jedini put da ću prikazati grafikon, OK--
02:35
we would expect that it goes down as the distance increases
44
137000
4000
očekivali bismo da se ona smanjuje kako se rastojanje povećava
02:39
from the center of the galaxy.
45
141000
2000
od centra galaksije.
02:41
When those measurements are made,
46
143000
1000
Kada se ta merenja izvrše,
02:42
instead what we find is that the speed is basically constant,
47
144000
3000
umesto toga nalazimo da je brzina u suštini konstantna,
02:45
as a function of distance.
48
147000
2000
kao funkcija rastojanja.
02:47
If it's constant, that means that the stars out here
49
149000
3000
Ako je konstantna, to znači da zvezde tamo
02:50
are feeling the gravitational effects of matter that we do not see.
50
152000
4000
osećaju gravitaciono dejstvo materije koje mi ne vidimo.
02:54
In fact, this galaxy and every other galaxy
51
156000
3000
Zapravo, ova galaksija i svaka druga galaksija
02:57
appears to be embedded in a cloud of this invisible dark matter.
52
159000
5000
su izgleda ubačene u oblak ove nevidljive tamne materije.
03:02
And this cloud of matter is much more spherical than the galaxy themselves,
53
164000
4000
A ovaj oblak materije je mnogo više sferičan nego same galaksije,
03:06
and it extends over a much wider range than the galaxy.
54
168000
4000
i prostire se preko veće oblasti od galaksije.
03:10
So we see the galaxy and fixate on that, but it's actually a cloud of dark matter
55
172000
4000
Znači vidimo galaksiju i to fiksiramo, ali to je zapravo oblak tamne materije
03:14
that's dominating the structure and the dynamics of this galaxy.
56
176000
5000
koji dominira strukturom i dinamikom ove galaksije.
03:19
Galaxies themselves are not strewn randomly in space;
57
181000
3000
Same galaksije nisu nasumično razbacane po prostoru;
03:22
they tend to cluster.
58
184000
2000
one imaju tendenciju da se grupišu.
03:24
And this is an example of a very, actually, famous cluster, the Coma cluster.
59
186000
3000
I ovo je primer veoma, zapravo, čuvene grupe: Coma grupe.
03:27
And there are thousands of galaxies in this cluster.
60
189000
3000
A postoje hiljade galaksija u ovoj grupi.
03:30
They're the white, fuzzy, elliptical things here.
61
192000
3000
One su ove bele, mutne, eliptične stvari ovde.
03:33
So these galaxy clusters -- we take a snapshot now,
62
195000
3000
Znači ove galaksije se grupišu - sada ih slikamo,
03:36
we take a snapshot in a decade, it'll look identical.
63
198000
3000
i ako ih slikamo za deset godina -- izgledaće isto.
03:39
But these galaxies are actually moving at extremely high speeds.
64
201000
4000
Ali ove galaksije se zapravo kreću veoma visokim brzinama.
03:43
They're moving around in this gravitational potential well of this cluster, OK.
65
205000
5000
One se kreću okolo u ovoj gravitacionoj potencijalnoj jami ove grupe, OK.
03:48
So all of these galaxies are moving.
66
210000
2000
Znači sve ove galaksije se kreću.
03:50
We can measure the speeds of these galaxies, their orbital velocities,
67
212000
4000
Možemo meriti brzine ovih galaksija, njihovu orbitalnu brzinu,
03:54
and figure out how much mass is in this cluster.
68
216000
2000
i izračunati koliko mase postoji u ovoj grupi.
03:56
And again, what we find is that there is much more mass there
69
218000
4000
I ponovo, vidimo da postoji mnogo više mase tu
04:00
than can be accounted for by the galaxies that we see.
70
222000
4000
nego što se može pripisati galaksijama koje vidimo.
04:04
Or if we look in other parts of the electromagnetic spectrum,
71
226000
2000
Ili ako posmatramo druge delove elektromagnetnog spektra,
04:06
we see that there's a lot of gas in this cluster, as well.
72
228000
3000
vidimo da postoji dosta gasa u ovoj grupi takođe.
04:09
But that cannot account for the mass either.
73
231000
2000
Ali ni to ne može objasniti masu.
04:11
In fact, there appears to be about ten times as much mass here
74
233000
3000
Zapravo, izgleda da postoji oko deset puta više mase ovde
04:14
in the form of this invisible or dark matter
75
236000
3000
u obliku ove nevidljive ili tamne materije
04:17
as there is in the ordinary matter, OK.
76
239000
4000
nego što postoji obične materije, OK.
04:21
It would be nice if we could see this dark matter a little bit more directly.
77
243000
4000
Bilo bi lakše kada bismo mogli da direktnije vidimo ovu tamnu materiju.
04:25
I'm just putting this big, blue blob on there, OK,
78
247000
2000
Staviću ovu veliku, plavu mrlju ovde, OK,
04:27
to try to remind you that it's there.
79
249000
2000
da bih vas podsetila da je tu.
04:29
Can we see it more visually? Yes, we can.
80
251000
3000
Da li je možemo jasnije videti? Da, možemo.
04:32
And so let me lead you through how we can do this.
81
254000
2000
Sada ću vam objasniti na koji način to možemo učiniti.
04:34
So here's an observer:
82
256000
2000
Ovo je posmatrač.
04:36
it could be an eye; it could be a telescope.
83
258000
2000
to može biti oko; može biti teleskop.
04:38
And suppose there's a galaxy out here in the universe.
84
260000
2000
I pretpostavimo da postoji galaksija tamo u univerzumu.
04:40
How do we see that galaxy?
85
262000
2000
Kako vidimo tu galaksiju?
04:42
A ray of light leaves the galaxy and travels through the universe
86
264000
3000
Zrak svetlosti napušta galaksiju i putuje kroz univerzum
04:45
for perhaps billions of years
87
267000
2000
možda milijardama godina
04:47
before it enters the telescope or your eye.
88
269000
3000
pre nego što dospe u teleskop ili vaše oko.
04:50
Now, how do we deduce where the galaxy is?
89
272000
3000
Sada, kako zaključujemo gde je ta galaksija?
04:53
Well, we deduce it by the direction that the ray is traveling
90
275000
3000
Pa, zaključujemo prema smeru u kome putuje zrak
04:56
as it enters our eye, right?
91
278000
2000
dok ulazi u naše oko, uredu?
04:58
We say, the ray of light came this way;
92
280000
2000
Kažemo, zrak svetlosti je došao odavde;
05:00
the galaxy must be there, OK.
93
282000
2000
galaksija mora da je tamo, OK.
05:02
Now, suppose I put in the middle a cluster of galaxies --
94
284000
4000
Sada, pretpostavimo da između stavim grupu galaksija --
05:06
and don't forget the dark matter, OK.
95
288000
2000
i ne zaboravite na tamnu materiju, OK.
05:08
Now, if we consider a different ray of light, one going off like this,
96
290000
4000
Sada, ako uzmemo u obzir drugi zrak svetlosti, koji ide ovako,
05:12
we now need to take into account
97
294000
2000
sada moramo uzeti u obzir
05:14
what Einstein predicted when he developed general relativity.
98
296000
3000
Ajnštanova predviđanja iz teorije opšte relativnost.
05:17
And that was that the gravitational field, due to mass,
99
299000
4000
A to je da gravitaciono polje, zbog mase,
05:21
will deflect not only the trajectory of particles,
100
303000
3000
skreće ne samo putanju čestica,
05:24
but will deflect light itself.
101
306000
3000
već skreće i samu svetlost.
05:27
So this light ray will not continue in a straight line,
102
309000
3000
Znači ovaj zrak svetlosti neće nastaviti da ide pravolinijski,
05:30
but would rather bend and could end up going into our eye.
103
312000
4000
već će se saviti i na kraju bi mogao da završi u vašem oku.
05:34
Where will this observer see the galaxy?
104
316000
3000
Gde će posmatrač videti galaksiju?
05:37
You can respond. Up, right?
105
319000
4000
Možete odgovoriti. Gore, jel' tako?
05:41
We extrapolate backwards and say the galaxy is up here.
106
323000
3000
Ekstrapoliramo unazad i kažemo da je galaksija tamo gore.
05:44
Is there any other ray of light
107
326000
1000
Da li postoji neki drugi zrak svetlosti
05:45
that could make into the observer's eye from that galaxy?
108
327000
3000
koji bi mogao da stigne do oka posmatrača iz te galaksije?
05:48
Yes, great. I see people going down like this.
109
330000
3000
Da, super. Vidim ljude koji ovako pokazuju.
05:51
So a ray of light could go down, be bent
110
333000
2000
Znači zrak svetlosti bi mogao da ide na dole, da se savije
05:53
up into the observer's eye,
111
335000
2000
u oko posmatrača,
05:55
and the observer sees a ray of light here.
112
337000
2000
i posmatrač vidi zrak svetlosti ovde.
05:57
Now, take into account the fact that we live in
113
339000
2000
Sada, uzmimo u obzir činjenicu da živimo
05:59
a three-dimensional universe, OK,
114
341000
2000
u trodimenzionalnom univerzumu, OK,
06:01
a three-dimensional space.
115
343000
2000
u trodimenzionalnom prostoru.
06:03
Are there any other rays of light that could make it into the eye?
116
345000
3000
Da li ima još zraka svetlosti koji mogu da dospeju u oko?
06:06
Yes! The rays would lie on a -- I'd like to see -- yeah, on a cone.
117
348000
6000
Da! Zraci bi ležali na --volela bih da vidim --da, na kupi.
06:12
So there's a whole ray of light -- rays of light on a cone --
118
354000
2000
Znači postoje zraci svetlosti -- zraci svetlosti na kupi --
06:14
that will all be bent by that cluster
119
356000
2000
koji će svi biti savijeni tom grupom
06:16
and make it into the observer's eye.
120
358000
3000
i dospeti u oko posmatrača.
06:19
If there is a cone of light coming into my eye, what do I see?
121
361000
5000
Ako postoji kupa svetlosti koja dolazi do mog oka, šta ja vidim?
06:24
A circle, a ring. It's called an Einstein ring. Einstein predicted that, OK.
122
366000
4000
Krug, prsten. To se naziva Ajnštajnovim prstenom -- Ajnštan je to predvideo, OK.
06:28
Now, it will only be a perfect ring if the source, the deflector
123
370000
5000
Sada, to će biti savršeni prsten ako su izvor, prepreka,
06:33
and the eyeball, in this case, are all in a perfectly straight line.
124
375000
5000
i oko, u ovom slučaju, u savršenoj pravoj liniji.
06:38
If they're slightly skewed, we'll see a different image.
125
380000
3000
Ako su malo ukrivo, videćemo drugačiju sliku.
06:41
Now, you can do an experiment tonight over the reception, OK,
126
383000
3000
Sada, možete probati eksperiment večeras na prijemu, OK,
06:44
to figure out what that image will look like.
127
386000
3000
da zaključite kako će ta slika izgledati.
06:47
Because it turns out that there is a kind of lens that we can devise,
128
389000
4000
Jer se ispostavlja da postoji sočivo koje možemo napraviti,
06:51
that has the right shape to produce this kind of effect.
129
393000
3000
koje je odgovarajućeg oblika da stvori tu vrstu efekta.
06:54
We call this gravitational lensing.
130
396000
2000
Ovo nazivamo gravitacionim sočivom.
06:56
And so, this is your instrument, OK.
131
398000
3000
I tako, ovo je vaš instrument, OK.
06:59
(Laughter).
132
401000
1000
(Smeh).
07:00
But ignore the top part.
133
402000
3000
Ali zanemarite gornji deo.
07:03
It's the base that I want you to concentrate, OK.
134
405000
3000
Želim da se koncentrišete na osnovu, OK.
07:06
So, actually, at home, whenever we break a wineglass,
135
408000
2000
Zapravo, kod kuće, kada god slomimo vinsku čašu,
07:08
I save the bottom, take it over to the machine shop.
136
410000
2000
Sačuvam dno, odnesem je do mašinske radionice.
07:10
We shave it off, and I have a little gravitational lens, OK.
137
412000
4000
Skinemo gornji deo i imamo malo gravitaciono sočivo, OK.
07:14
So it's got the right shape to produce the lensing.
138
416000
2000
Znači to je pravi oblik za pravljenje sočiva.
07:16
And so the next thing you need to do in your experiment
139
418000
2000
I sledeća stvar koju želim da uradite u vašem eksperimentu,
07:18
is grab a napkin. I grabbed a piece of graph paper -- I'm a physicist. (Laughter)
140
420000
4000
jeste da uzmete salvetu. Ja sam uzela parče milimetarske hartije. Ja sam ipak fizičar. (Smeh)
07:22
So, a napkin. Draw a little model galaxy in the middle.
141
424000
4000
Znač, salvetu. Nacrtajte mali model galaksije u sredini.
07:26
And now put the lens over the galaxy,
142
428000
3000
I onda stavite sočivo preko galaksije,
07:29
and what you'll find is that you'll see a ring, an Einstein ring.
143
431000
3000
i videćete da ste dobili prsten, Ajnštajnov prsten.
07:32
Now, move the base off to the side,
144
434000
3000
A sada pomerite osnovu na stranu,
07:35
and the ring will split up into arcs, OK.
145
437000
3000
i prsten će se podeliti na lukove, OK.
07:38
And you can put it on top of any image.
146
440000
2000
I možete ga staviti preko bilo koje slike.
07:40
On the graph paper, you can see
147
442000
1000
Na milimetarskoj hartiji možete videti
07:41
how all the lines on the graph paper have been distorted.
148
443000
2000
kako su sve linije na milimetarskoj hartiji izobličene.
07:43
And again, this is a kind of an accurate model
149
445000
3000
I ponovo, ovo je neka vrsta preciznog modela
07:46
of what happens with the gravitational lensing.
150
448000
2000
onoga što se dešava sa gravitacionim sočivom.
07:48
OK, so the question is: do we see this in the sky?
151
450000
4000
OK, znači pitanje je: da li vidimo ovo na nebu?
07:52
Do we see arcs in the sky when we look at, say, a cluster of galaxies?
152
454000
4000
Da li vidimo lukove na nebu kada gledamo, na primer, grupu galaksija?
07:56
And the answer is yes.
153
458000
2000
I odgovor je: da.
07:58
And so, here's an image from the Hubble Space Telescope.
154
460000
2000
I tako, ovo je slika od svemirskog teleskopa Hubble.
08:00
Many of the images you are seeing
155
462000
2000
I mnoge od slika koje gledate
08:02
are earlier from the Hubble Space Telescope.
156
464000
2000
su ranije dobijene sa svemirskog teleskopa Hubble.
08:04
Well, first of all, for the golden shape galaxies --
157
466000
2000
Kao prvo, za galaksije zlatnog oblika --
08:06
those are the galaxies in the cluster.
158
468000
3000
to su galaksije u grupi.
08:09
They're the ones that are embedded in that sea of dark matter
159
471000
4000
To su one ugrađene u more tamne materije
08:13
that are causing the bending of the light
160
475000
2000
koje izazivaju savijanje svetlosti
08:15
to cause these optical illusions, or mirages, practically,
161
477000
3000
da bi izazvale optičke iluzije, fatamorgane, praktično,
08:18
of the background galaxies.
162
480000
2000
galaksija u pozadini.
08:20
So the streaks that you see, all these streaks,
163
482000
3000
Znači crte koje vidite, sve ove crte,
08:23
are actually distorted images of galaxies that are much further away.
164
485000
4000
su zapravo iskrivljene slike galaksija koje su mnogo više udaljene.
08:27
So what we can do, then, is based on how much distortion
165
489000
3000
Ono što možemo je da, onda, na osnovu stepena iskrivljenja
08:30
we see in those images, we can calculate how much mass
166
492000
4000
koje vidimo na tim slikama, izračunamo koliko mase
08:34
there must be in this cluster.
167
496000
2000
mora da postoji u ovoj grupi.
08:36
And it's an enormous amount of mass.
168
498000
2000
A to je ogromna količina mase.
08:38
And also, you can tell by eye, by looking at this,
169
500000
2000
I takođe, možete videti golim okom, dok ovo posmatrate,
08:40
that these arcs are not centered on individual galaxies.
170
502000
4000
da ovi lukovi nisu centrirani u pojedinačnim galaksijama;
08:44
They are centered on some more spread out structure,
171
506000
4000
oni su centrirani u nekoj raširenijoj strukturi.
08:48
and that is the dark matter
172
510000
4000
A to je tamna materija
08:52
in which the cluster is embedded, OK.
173
514000
3000
u kojoj je ugrađena grupa, OK.
08:55
So this is the closest you can get to kind of seeing
174
517000
2000
Znači to je najbliže što možemo doći da vidimo
08:57
at least the effects of the dark matter with your naked eye.
175
519000
3000
barem efekte tamne materije golim okom.
09:00
OK, so, a quick review then, to see that you're following.
176
522000
3000
OK, kratak pregled, da vidim da li pratite.
09:03
So the evidence that we have
177
525000
2000
Znači dokazi koje imamo
09:05
that a quarter of the universe is dark matter --
178
527000
2000
da četvrtinu univerzuma čini tamna materija --
09:07
this gravitationally attracting stuff --
179
529000
2000
ono što privlači putem gravitacije --
09:09
is that galaxies, the speed with which stars orbiting galaxies
180
531000
4000
jeste da galaksije, brzine kojim zvezde orbitiraju oko galaksija
09:13
is much too large; it must be embedded in dark matter.
181
535000
3000
jesu prevelike; mora da bude ugrađena u tamnu materiju.
09:16
The speed with which galaxies within clusters are orbiting is much too large;
182
538000
4000
Brzina kojom galaksije u okviru grupa orbitiraju je prevelika;
09:20
it must be embedded in dark matter.
183
542000
2000
mora da je ugrađena u tamnu materiju.
09:22
And we see these gravitational lensing effects, these distortions
184
544000
4000
I vidimo ove efekte gravitacionog sočiva, ova izobličenja
09:26
that say that, again, clusters are embedded in dark matter.
185
548000
3000
koja ponovo ukazuju da su grupe ugrađene u tamnu materiju.
09:29
OK. So now, let's turn to dark energy.
186
551000
4000
OK. Hajde sada da se bavimo tamnom energijom.
09:33
So to understand the evidence for dark energy, we need to discuss something
187
555000
3000
Da bi razumeli dokaze za tamnu energiju, potrebno je razmotriti nešto
09:36
that Stephen Hawking referred to in the previous session.
188
558000
4000
što je Stephen Hawking spomenuo u prethodnoj sesiji.
09:40
And that is the fact that space itself is expanding.
189
562000
4000
A to je činjenica da se sam prostor širi.
09:44
So if we imagine a section of our infinite universe --
190
566000
5000
Znači ako zamislimo deo našeg beskonačnog univerzuma, OK,
09:49
and so I've put down four spiral galaxies, OK --
191
571000
3000
pa sam ovde stavila četiri spiralne galaksije, OK.
09:52
and imagine that you put down a set of tape measures,
192
574000
4000
I zamislimo da stavite nekoliko metara za merenje,
09:56
so every line on here corresponds to a tape measure,
193
578000
2000
tako da se svaka linija ovde poklapa sa metrom za merenje --
09:58
horizontal or vertical, for measuring where things are.
194
580000
4000
horizontalno ili vertikalno -- za merenje gde se šta nalazi.
10:02
If you could do this, what you would find
195
584000
2000
Ako biste to mogli da uradite, videli biste
10:04
that with each passing day, each passing year,
196
586000
3000
svakim danom, svakom godinom,
10:07
each passing billions of years, OK,
197
589000
3000
svakom milijardom godina, OK,
10:10
the distance between galaxies is getting greater.
198
592000
3000
da se rastojanje između galaksija povećava.
10:13
And it's not because galaxies are moving
199
595000
1000
A to nije zato šte se galaksije
10:14
away from each other through space.
200
596000
3000
međusobno udaljuju kroz svemir;
10:17
They're not necessarily moving through space.
201
599000
2000
nije baš da se kreću kroz svemir.
10:19
They're moving away from each other
202
601000
2000
One se međusobno udaljavaju
10:21
because space itself is getting bigger, OK.
203
603000
3000
jer se sam svemir povećava, OK.
10:24
That's what the expansion of the universe or space means.
204
606000
4000
To znači širenje univerzuma ili prostora.
10:28
So they're moving further apart.
205
610000
2000
Znači one se udaljavaju.
10:30
Now, what Stephen Hawking mentioned, as well,
206
612000
4000
Sada, ono što je Stephen Hawking pomenuo, takođe,
10:34
is that after the Big Bang, space expanded at a very rapid rate.
207
616000
6000
jeste da se nakon Velikog praska, prostor širio veoma velikom brzinom.
10:40
But because gravitationally attracting matter
208
622000
4000
Ali pošto je materija koja ima gravitaciono privlačenje
10:44
is embedded in this space,
209
626000
2000
ugrađena u ovaj prostor,
10:46
it tends to slow down the expansion of the space, OK.
210
628000
3000
ona ima tendenciju da usporava širenje prostora, OK.
10:49
So the expansion slows down with time.
211
631000
3000
Znači širenje se usporava s vremenom.
10:52
So, in the last century, OK, people debated
212
634000
4000
Znači, u prošlom veku, ljudi su raspravljali
10:56
about whether this expansion of space would continue forever;
213
638000
5000
o tome da li će se ovo širenje prostora nastaviti zauvek,
11:01
whether it would slow down, you know,
214
643000
2000
da li će se usporiti, znate,
11:03
will be slowing down, but continue forever;
215
645000
2000
da li će se usporavati, ali nastavljati zauvek.
11:05
slow down and stop, asymptotically stop;
216
647000
5000
Usporiti i stati, asimptotski stati,
11:10
or slow down, stop, and then reverse, so it starts to contract again.
217
652000
5000
ili usporiti, zaustaviti, a onda, obratno ponovo početi da se skuplja.
11:15
So a little over a decade ago,
218
657000
2000
Pre nešto više od jedne decenije,
11:17
two groups of physicists and astronomers
219
659000
5000
dve grupe fizičara i astronoma
11:22
set out to measure the rate at which
220
664000
2000
su počeli da mere stopu po kojoj
11:24
the expansion of space was slowing down, OK.
221
666000
4000
se širenje prostora usporava, OK.
11:28
By how much less is it expanding today,
222
670000
2000
Za koliko manje se širi danas,
11:30
compared to, say, a couple of billion years ago?
223
672000
3000
u poređenju sa, na primer, pre par milijardi godina?
11:33
The startling answer to this question, OK, from these experiments,
224
675000
5000
Zapanjujući odgovor na ovo pitanje, iz ovih eksperimenata,
11:38
was that space is expanding at a faster rate today
225
680000
4000
jeste da se prostor širi brže danas,
11:42
than it was a few billion years ago, OK.
226
684000
3000
nego pre nekoliko milijardu godina, OK.
11:45
So the expansion of space is actually speeding up.
227
687000
3000
Znači širenje prostora se zapravo ubrzava.
11:48
This was a completely surprising result.
228
690000
3000
Ovo je bio potpuno iznenađujući rezultat.
11:51
There is no persuasive theoretical argument for why this should happen, OK.
229
693000
6000
Ne postoji ubedljiv teorijski argument zašto se ovo događa, OK.
11:57
No one was predicting ahead of time this is what's going to be found.
230
699000
3000
Niko nije unapred predvideo da će se to utvrditi.
12:00
It was the opposite of what was expected.
231
702000
2000
Očekivalo se upravo suprotno.
12:02
So we need something to be able to explain that.
232
704000
3000
Zato nam je potrebno nešto što će moći to da objasni.
12:05
Now it turns out, in the mathematics,
233
707000
2000
Sada ispada, u matematici,
12:07
you can put it in as a term that's an energy,
234
709000
4000
možete to nazvati vrstom energije.
12:11
but it's a completely different type of energy
235
713000
1000
Ali to je potpuno drugačija vrsta energije
12:12
from anything we've ever seen before.
236
714000
2000
od bilo čega što smo do sada videli.
12:14
We call it dark energy,
237
716000
2000
Mi to nazivamo tamnom energijom,
12:16
and it has this effect of causing space to expand.
238
718000
3000
i ima dejstvo da izazove da se prostor širi.
12:19
But we don't have a good motivation
239
721000
2000
Ali nemamo dobar razlog
12:21
for putting it in there at this point, OK.
240
723000
2000
da to uvedemo u ovom trenutku, OK.
12:23
So it's really unexplained as to why we need to put it in.
241
725000
3000
Znači potpuno je neobjašnjeno zašto moramo da to unesemo.
12:26
Now, so at this point, then, what I want to really emphasize to you,
242
728000
4000
Sada, u ovom trenutku, onda, ono što želim da vam naglasim,
12:30
is that, first of all, dark matter and dark energy
243
732000
2000
jeste da su kao prvo, tamna materija i tamna energija
12:32
are completely different things, OK.
244
734000
2000
potpuno različite stvari, OK.
12:34
There are really two mysteries out there as to what makes up most of the universe,
245
736000
4000
Postoje stvarno dve misterije o tome šta čini veći deo univerzuma,
12:38
and they have very different effects.
246
740000
3000
i one imaju veoma različita dejstva.
12:41
Dark matter, because it gravitationally attracts,
247
743000
3000
Tamna materija, pošto gravitaciono privlači,
12:44
it tends to encourage the growth of structure, OK.
248
746000
4000
ima tendenciju da ohrabruje rast strukture, OK.
12:48
So clusters of galaxies will tend to form,
249
750000
3000
Tako da će grupe galaksija imati tendenciju da se formiraju,
12:51
because of all this gravitational attraction.
250
753000
2000
zbog ovog gravitacionog privlačenja.
12:53
Dark energy, on the other hand,
251
755000
2000
Tamna energija, s druge strane,
12:55
is putting more and more space between the galaxies,
252
757000
4000
stvara sve više i više prostora između galaksija.
12:59
makes it, the gravitational attraction between them decrease,
253
761000
3000
Čini da se - gravitaciona privlačnost među njima - smanjuje,
13:02
and so it impedes the growth of structure.
254
764000
3000
i tako ometa rast strukture.
13:05
So by looking at things like clusters of galaxies,
255
767000
3000
I tako posmatrajući stvari poput grupa galaksija,
13:08
and how they -- their number density,
256
770000
4000
i kako one -- njihov broj gustine,
13:12
how many there are as a function of time --
257
774000
2000
koliko ih ima kao funkcija vremena --
13:14
we can learn about how dark matter and dark energy
258
776000
4000
učimo o tome kako se tamna materija i tamna energija
13:18
compete against each other in structure forming.
259
780000
3000
međusobno takmiče u formiranju strukture.
13:21
In terms of dark matter, I said that we don't have any,
260
783000
3000
Što se tiče tamne materije, rekla sam da nemamo,
13:24
you know, really persuasive argument for dark energy.
261
786000
4000
znate, stvarno ubedljiv argument za tamnu energiju.
13:28
Do we have anything for dark matter? And the answer is yes.
262
790000
3000
Da li imamo nešto za tamnu materiju? I odogovor je: da.
13:31
We have well-motivated candidates for the dark matter.
263
793000
3000
Imamo dobro motivisane kandidate za tamnu materiju.
13:34
Now, what do I mean by well motivated?
264
796000
3000
Šta znači dobro motivisane?
13:37
I mean that we have mathematically consistent theories
265
799000
5000
Mislim da imamo matematički konzistentne teorije
13:42
that were actually introduced
266
804000
2000
koje su zapravo uvedene
13:44
to explain a completely different phenomenon, OK,
267
806000
3000
da objasne potpuno različite fenomene, OK,
13:47
things that I haven't even talked about,
268
809000
2000
stvari o kojima nisam čak ni govorila,
13:49
that each predict the existence
269
811000
3000
koje previđaju postojanje
13:52
of a very weakly interacting, new particle.
270
814000
3000
veoma slabo reagujuće nove čestice.
13:55
So, this is exactly what you want in physics:
271
817000
2000
Zapravo ovo je baš ono što želite u fizici:
13:57
where a prediction comes out of a mathematically consistent theory
272
819000
4000
kada previđanje potekne iz matematički konzistentne teorije
14:01
that was actually developed for something else.
273
823000
2000
koja je zapravo razvijena za nešto drugo.
14:03
But we don't know if either of those
274
825000
3000
Ali mi ne znamo da li je ijedna od ovih
14:06
are actually the dark matter candidate, OK.
275
828000
3000
stvarno kandidat za tamnu materiju, OK.
14:09
One or both, who knows? Or it could be something completely different.
276
831000
3000
Jedna, ili obe, ko zna? Ili je možda nešto potpuno drugačije.
14:12
Now, we look for these dark matter particles
277
834000
2000
Sada tražimo ove čestice tamne materije
14:14
because, after all, they are here in the room, OK,
278
836000
3000
jer ipak, one su ovde u sobi, OK,
14:17
and they didn't come in the door.
279
839000
1000
a nisu ušle kroz vrata.
14:18
They just pass through anything.
280
840000
2000
One jednostavno prolaze kroz bilo šta.
14:20
They can come through the building, through the Earth --
281
842000
2000
One mogu proći kroz zgradu, kroz zemlju;
14:22
they're so non-interacting.
282
844000
2000
one nemaju interakciju.
14:24
So one way to look for them is to build detectors
283
846000
3000
Znači jedan način da ih posmatramo jeste da izgradimo detektore
14:27
that are extremely sensitive to a dark matter particle coming through and bumping it.
284
849000
4000
koji su izuzetno osetljivi na tamne čestice koje prolaze kroz i sudaraju se s njima.
14:31
So a crystal that will ring if that happens.
285
853000
3000
Znači kristal koji će zvoniti ako se to dogodi.
14:34
So one of my colleagues up the road and his collaborators
286
856000
2000
Pa su jedan moj kolega ovde niz ulicu i njegovi saradnici
14:36
have built such a detector.
287
858000
2000
sagradili takav detektor.
14:38
And they've put it deep down in an iron mine in Minnesota,
288
860000
3000
I postavili ga duboko u rudniku gvožđa u Minesoti,
14:41
OK, deep under the ground, and in fact, in the last couple of days
289
863000
3000
OK? -- duboko pod zemljom -- i zapravo, u poslednjih nekoliko dana
14:44
announced the most sensitive results so far.
290
866000
3000
su objavili najosetljivije rezultate do sada.
14:47
They haven't seen anything, OK, but it puts limits on what the mass
291
869000
3000
Ništa nisu videli, OK, ali to postavlja granice onoga što su masa
14:50
and the interaction strength of these dark matter particles are.
292
872000
3000
i snaga interakcija ovih čestica tamne materije.
14:53
There's going to be a satellite telescope launched later this year
293
875000
4000
Biće lansiran satelitski teleskop kasnije ove godine.
14:57
and it will look towards the middle of the galaxy,
294
879000
3000
I biće uperen ka središtu galaksije,
15:00
to see if we can see dark matter particles annihilating
295
882000
2000
tako da možemo da vidimo čestice tamne materije kako uništavaju
15:02
and producing gamma rays that could be detected with this.
296
884000
4000
i proizvode gama zrake koji bi mogli da se ovim detektuju.
15:06
The Large Hadron Collider, a particle physics accelerator,
297
888000
3000
Veliki hadronski sudarač, akcelerator čestica,
15:09
that we'll be turning on later this year.
298
891000
3000
koji će biti uključen kasnije ove godine.
15:12
It is possible that dark matter particles might be produced
299
894000
3000
Moguće je da će nastati čestice tamne materije
15:15
at the Large Hadron Collider.
300
897000
2000
u Velikom hadronskom sudaraču.
15:17
Now, because they are so non-interactive,
301
899000
1000
Sada, pošto su toliko neinteraktivne,
15:18
they will actually escape the detector,
302
900000
3000
one će zapravo pobeći detektoru,
15:21
so their signature will be missing energy, OK.
303
903000
3000
pa će njihov otisak biti energija koja nedostaje, OK.
15:24
Now, unfortunately, there is a lot of new physics
304
906000
3000
Nažalost, ima mnogo nove fizike
15:27
whose signature could be missing energy,
305
909000
2000
čiji bi otisak takođe mogao biti energija koja nedostaje,
15:29
so it will be hard to tell the difference.
306
911000
2000
pa će biti teško napraviti razliku.
15:31
And finally, for future endeavors, there are telescopes being designed
307
913000
5000
I na kraju, za buduće napore, prave se teleskopi
15:36
specifically to address the questions of dark matter and dark energy --
308
918000
4000
konkretno da se bave pitanjima tamne materije i tamne energije:
15:40
ground-based telescopes, and there are three space-based telescopes
309
922000
3000
teleskopi koji će biti na zemlji. I postoji tri teleskopa baziranih u svemiru
15:43
that are in competition right now
310
925000
2000
koji su sada u konkurenciji
15:45
to be launched to investigate dark matter and dark energy.
311
927000
3000
da se lansiraju kako bi ispitivali tamnu materiju i tamnu energiju.
15:48
So in terms of the big questions:
312
930000
2000
Znači što se tiče velikih pitanja:
15:50
what is dark matter? What is dark energy?
313
932000
2000
Šta je tamna materija? Šta je tamna energija?
15:52
The big questions facing physics.
314
934000
2000
Velika pitanja sa kojima je suočena fizika.
15:54
And I'm sure you have lots of questions,
315
936000
3000
I sigurna sam da vi imate puno pitanja.
15:57
which I very much look forward to addressing
316
939000
2000
Na koja ću rado odgovoriti
15:59
over the next 72 hours, while I'm here. Thank you.
317
941000
2000
tokom sledećih 72 sata dok sam ovde, OK. Hvala.
16:01
(Applause)
318
943000
3000
(Aplauz)
ABOUT THE SPEAKER
Patricia Burchat - Particle physicistPatricia Burchat studies the structure and distribution of dark matter and dark energy. These mysterious ingredients can't be measured in conventional ways, yet form a quarter of the mass of our universe.
Why you should listen
Patricia Burchat studies the universe's most basic ingredients -- the mysterious dark energy and dark matter that are massively more abundant than the visible stars and galaxies. She is one of the founders of the BaBar Collaboration at the Stanford Linear Accelerator Center, a project that's hoping to answer the question, "If there are as many anti-particles as there are particles, why can't we see all these anti-particles?"
She's a member of the Large Synoptic Survey Telescope project, which will allow scientists to monitor exploding supernovae and determine how fast the universe is expanding -- and map how mass is distributed throughout the universe. She's also part of Fermilab Experiment E791, studying the production and decay of charmed particles. Burchat received a Guggenheim Fellowship in 2005.
Patricia Burchat | Speaker | TED.com