Garik Israelian: What's inside a star?

47,503 views ・ 2009-10-01

TED


Please double-click on the English subtitles below to play the video.

Prevodilac: Sofija Dorotic Lektor: Ana Zivanovic-Nenadovic
00:18
I have a very difficult task.
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Imam jako težak zadatak.
00:21
I'm a spectroscopist.
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Spektroskopista sam.
00:24
I have to talk about astronomy without showing you
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Treba da vam pričam o astronomiji, a da vam ne pokažem
00:26
any single image of nebulae or galaxies, etc.
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ijednu sliku nebule, galaksije i tako dalje.
00:30
because my job is spectroscopy.
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Ja radim kao spektroskopista
00:32
I never deal with images.
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i nikada ne radim sa fotografijama.
00:35
But I'll try to convince you
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Pokušaću da vas uverim
00:37
that spectroscopy is actually something which can
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da je spektroskopija nešto
00:39
change this world.
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što može promeniti svet.
00:42
Spectroscopy can probably answer the question,
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Spektroskopija verovatno može da odgovori na pitanje
00:45
"Is there anybody out there?"
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"Ima li koga tamo?"
00:47
Are we alone? SETI.
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Da li smo sami? SETI.
00:49
It's not very fun to do spectroscopy.
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Spektroskopija nije jako zabavna.
00:52
One of my colleagues in Bulgaria,
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Jedna moj koleginica iz Bugarske,
00:54
Nevena Markova, spent about 20 years
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Nevena Markov, provela je dvadeset godina
00:56
studying these profiles.
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proučavajući ovakve profile.
00:59
And she published 42 articles
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Objavila je 42 članka
01:01
just dedicated to the subject.
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posvećenih toj temi.
01:03
Can you imagine? Day and night, thinking,
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Možete li da zamislite? Dan i noć, razmišljati,
01:05
observing, the same star for 20 years
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posmatrati, istu zvezdu dvadeset godina
01:08
is incredible.
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je neverovatno.
01:10
But we are crazy. We do these things.
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Ali mi smo ludi. Mi radimo takve stvari.
01:12
(Laughter)
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(Smeh)
01:14
And I'm not that far.
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Ja nisam tako daleko.
01:16
I spent about eight months working on these profiles.
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Proveo sam osam meseci radeći na ovim profilima.
01:19
Because I've noticed
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Primetio sam
01:21
a very small symmetry
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vrlo malu simetriju
01:23
in the profile of one of the planet host stars.
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u profilu jedne od zvezda koje imaju planete
01:25
And I thought, well maybe there is Lithium-6 in this star,
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Mislio sam, možda je to litijum VI u ovoj zvezdi,
01:29
which is an indication that this star
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što je indikator da je ova zvezda
01:31
has swallowed a planet.
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progutala planetu.
01:33
Because apparently you can't have this fragile isotope
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Jer navodno, ne možete imati ovaj krhki izotop
01:36
of Lithium-6 in the atmospheres of sun-like stars.
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litijuma VI u atmosferi zvezda nalik Suncu.
01:40
But you have it in planets and asteroids.
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Ali postoji u planetama i asteroidima.
01:43
So if you engulf planet or large number of asteroids,
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Dakle, ako ste progutali planetu ili veliki broj asteroida,
01:49
you will have this Lithium-6 isotope
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imaćete ovaj izotop litijuma VI
01:52
in the spectrum of the star.
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u spektru zvezde.
01:54
So I invested more than eight months
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Tako da sam uložio više od osam meseci
01:58
just studying the profile of this star.
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samo u proučavanje profila linije litijuma ove zvezde.
02:00
And actually it's amazing,
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Zapravo je fascinantno,
02:02
because I got phone calls from many reporters asking,
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jer su me zvali mnogi novinari i pitali
02:04
"Have you actually seen the planet going into a star?"
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"Da li ste stvarno videli kako planeta ulazi u zvezdu?"
02:07
Because they thought that if you are having a telescope,
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Oni misle da ako imate teleskop,
02:11
you are an astronomer so what you are doing
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vi ste astronom i to što radite je
02:13
is actually looking in a telescope.
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zapravo gledanje kroz teleskop.
02:15
And you might have seen the planet going into a star.
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I možda ste videli kako planeta ulazi u zvezdu.
02:19
And I was saying, "No, excuse me.
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Na to sam odgovorio: "Ne, izvinite.
02:21
What I see is this one."
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Ono što ja vidim je ovo."
02:23
(Laughter)
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(Smeh)
02:24
It's just incredible. Because nobody understood really.
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To je neverovatno. Jer niko zapravo nije razumeo.
02:27
I bet that there were very few people
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Mogu se kladiti da je vrlo malo ljudi
02:29
who really understood what I'm talking about.
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koji su stvarno razumeli o čemu se radi.
02:32
Because this is the indication that the planet went into the star.
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Jer je ovo pokazatelj da je planeta ušla u zvezdu.
02:36
It's amazing.
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To je neverovatno.
02:39
The power of spectroscopy
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Moć spektroskopije
02:41
was actually realized
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je zapravo ostvarena
02:43
by Pink Floyd already in 1973.
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sa Pink Flojdom već 1973.
02:47
(Laughter)
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(Smeh)
02:48
Because they actually said that
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Oni su zapravo rekli
02:51
you can get any color you like
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kako možete dobiti bilo koju boju koju želite
02:53
in a spectrum.
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iz spektra.
02:55
And all you need is time and money
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A sve što vam je potrebno je vreme i novac
02:57
to make your spectrograph.
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kako biste napravili sopstveni spektrograf.
02:59
This is the number one high resolution,
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Ovo je najbolji spektrograf visoke rezolucije,
03:02
most precise spectrograph on this planet, called HARPS,
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najprecizniji spektrograf na ovoj planeti, pod nazivom HARPS,
03:05
which is actually used to detect
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koji se zapravo koristi za otkrivanje
03:07
extrasolar planets and sound waves
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ekstrasolarnih planeta i zvučnih talasa
03:09
in the atmospheres of stars.
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u atmosferama zvezda.
03:11
How we get spectra?
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Kako dobijamo spektar?
03:14
I'm sure most of you know from school physics
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Verujem da većina vas to zna iz fizike iz škole
03:17
that it's basically splitting a white light
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da je to u suštini prelamanje belog svetla
03:21
into colors.
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na boje.
03:23
And if you have a liquid hot mass,
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A ako imate tečnu vruću masu,
03:26
it will produce something which we call a continuous spectrum.
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ona proizvodi, kako mi kažemo, neprekidan spektar.
03:30
A hot gas is producing emission lines only,
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Vruć gas proizvodi samo emisione linije,
03:33
no continuum.
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ne kontinuum.
03:35
And if you place a cool gas in front of a
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Ako stavite hladan gas ispred
03:39
hot source,
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vrućeg izvora,
03:41
you will see certain patterns
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sigurno će te videti štablon
03:43
which we call absorption lines.
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koji zovemo apsorpcione linije.
03:45
Which is used actually to identify chemical elements
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Oni se, zapravo, koriste za identifikaciju hemijskih elemenata
03:48
in a cool matter,
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u hladnoj materiji,
03:50
which is absorbing exactly at those frequencies.
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koji budu apsorbovani na tim frekvencijama.
03:53
Now, what we can do with the spectra?
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Sada, šta možemo učiniti sa tim spektrima?
03:56
We can actually study line-of-sight velocities
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Mi možemo proučavati liniju radijalne brzine
03:59
of cosmic objects.
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kosmičkih objekata.
04:01
And we can also study chemical composition
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Možemo proučavati i hemijski sastav
04:04
and physical parameters of stars,
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i fizičke parametre zvezda,
04:06
galaxies, nebulae.
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galaksija, nebula.
04:08
A star is the most simple object.
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Zvezda je najprostiji objekat.
04:10
In the core, we have thermonuclear reactions going on,
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U središtu se odvijaju termonuklearne reakcije
04:14
creating chemical elements.
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koje stvaraju hemijske elemente.
04:16
And we have a cool atmosphere.
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I imamo hladnu atmosferu.
04:18
It's cool for me.
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Za mene je hladna.
04:20
Cool in my terms is three or four or five thousand degrees.
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U smislu da je tri ili četiri hiljade stepeni za mene hladno .
04:24
My colleagues in infra-red astronomy
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Moje kolege u infracrvenoj astronomiji
04:26
call minus 200 Kelvin is cool for them.
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kažu da je minus 200 Kelvina hladno za njih.
04:31
But you know, everything is relative.
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Ali znate, sve je relativno.
04:33
So for me 5,000 degrees is pretty cool.
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Tako da je 5.000 stepeni za mene prilično hladno.
04:36
(Laughter)
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(Smeh)
04:37
This is the spectrum of the Sun --
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Ovo je spektar Sunca -
04:40
24,000 spectral lines,
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24.000 spektralnih linija,
04:43
and about 15 percent of these lines is not yet identified.
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i oko petnaest odsto tih linija još nije identifikovano.
04:47
It is amazing. So we are in the 21st century,
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To je neverovatno. Evo nas u dvadest prvom veku
04:50
and we still cannot properly understand
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i još uvek ne razumemo u potpunosti
04:52
the spectrum of the sun.
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spektar Sunca.
04:54
Sometimes we have to deal with
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Ponekad imamo posla sa
04:56
just one tiny, weak spectral line
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samo jednom tankom, slabom, spektralnom linijom
04:59
to measure the composition of that chemical element in the atmosphere.
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pomoću koje merimo sastav hemijskog elementa u atmosferi.
05:03
For instance, you see the spectral line of the gold
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Na primer, vidite da je spektralna linija zlata
05:06
is the only spectral line in the spectrum of the Sun.
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jedina spektralna linija u spektru Sunca.
05:09
And we use this weak feature
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I mi korisitmo ovu slabu odliku
05:11
to measure the composition
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da bismo izmerili sastav
05:13
of gold in the atmosphere of the Sun.
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zlata u atmosferi Sunca.
05:16
And now this is a work in progress.
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Ovaj posao je trenutno u toku.
05:19
We have been dealing with a similarly very weak feature,
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Već smo se bavili sličnim, vrlo slabim karakteristikama,
05:23
which belongs to osmium.
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koje pripadaju osmiumu.
05:25
It's a heavy element produced in thermonuclear
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To je težak elemenat nastao u termonuklearnim
05:29
explosions of supernovae.
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eksplozijama supernove.
05:31
It's the only place where you can produce, actually, osmium.
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To je jedino mesto gde zapravo možete stvoriti osmium.
05:34
Just comparing the composition of osmium
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Samo uporedjujući sastav osmiuma
05:38
in one of the planet host stars,
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u zvezdama oko kojih se nalaze planete
05:40
we want to understand why there is so much
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želimo shvatiti zašto je toliko
05:42
of this element.
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tog elementa.
05:44
Perhaps we even think that maybe
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Možda mislimo da su
05:47
supernova explosions trigger formations of planets and stars.
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eksplozije supernova okidači za stvaranje planeta i zvezda.
05:51
It can be an indication.
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To može biti pokazatelj.
05:54
The other day, my colleague from Berkeley,
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Pre neki dan, moj kolega sa Berklija,
05:56
Gibor Basri, emailed me
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Gibor Basri, mi je poslao mejlom
05:58
a very interesting spectrum,
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veoma zanimljiv spektar
06:00
asking me, "Can you have a look at this?"
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pitajući me, "Možeš li ga pogledati?"
06:02
And I couldn't sleep, next two weeks,
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I nisam mogao spavati sledeće dve nedelje.
06:06
when I saw the huge amount of oxygen
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kada sam video ogromne količine kiseonika
06:09
and other elements in the spectrum of the stars.
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i drugih elemenata u spektru zvezda.
06:11
I knew that there is nothing like that observed in the galaxy.
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Znam da nikad tako nešto nije uočeno u galaksiji.
06:15
It was incredible. The only conclusion we could make from this
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Bilo je neverovatno. Jedini zaključak koji smo mogli doneti iz toga
06:19
is clear evidence that there was a supernova explosion
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jeste da je ovo jasan dokaz da se desila eksplozija supernove.
06:22
in this system, which polluted the atmosphere
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u tom sistemu, koja je zagadila atmosferu
06:25
of this star.
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ove zvezde.
06:27
And later a black hole was formed
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A zatim je nastala crna rupa
06:29
in a binary system,
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u binarnom sistemu,
06:31
which is still there with a mass of about
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koji je još uvek tamo s masom od oko
06:33
five solar masses.
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pet sunčevih masa.
06:35
This was considered as first evidence that actually black holes
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To se smatralo prvim dokazom da crne rupe zapravo
06:38
come from supernovae explosions.
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nastaju eksplozijama supernova.
06:42
My colleagues, comparing composition of chemical elements
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Moje kolege, poredeći sastav hemijskih elemenata
06:44
in different galactic stars,
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u različitim zvezdama u galaksijama
06:46
actually discovered alien stars in our galaxy.
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su zapravo otkrile strane zvezde u našoj galaksiji.
06:50
It's amazing that you can go so far
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Fascinantno je da možete tako daleko otići
06:53
simply studying the chemical composition of stars.
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samo proučavajući hemijski sastav zvezda.
06:57
They actually said that one of the stars you see in the spectra
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Oni su zapravo ustanovili da je jedna zvezda iz spektra
07:00
is an alien. It comes from a different galaxy.
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stranac. Ona dolazi iz druge galaksije.
07:03
There is interaction of galaxies. We know this.
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Postoji interakcija galaksija. Za to znamo.
07:06
And sometimes they just capture stars.
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One ponekad prosto otmu zvezde.
07:11
You've heard about solar flares.
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Čuli ste za solarne baklje.
07:14
We were very surprised to discover
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Bili smo jako iznenađeni otkrićem
07:16
a super flare,
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super baklje,
07:18
a flare which is thousands of millions of times
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baklje koja je hiljadu miliona puta
07:22
more powerful than those we see in the Sun.
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jača od one koju vidimo na Suncu.
07:24
In one of the binary stars in our galaxy
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U jednoj binarnoj zvezdi naše galaksije
07:27
called FH Leo,
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zvanoj FH Lav,
07:29
we discovered the super flare.
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otkrili smo super baklju.
07:31
And later we went to study the spectral stars
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Kasnije smo počeli proučavati spektralne zvezde
07:35
to see is there anything strange with these objects.
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kako bismo videli ima li u njima nečeg neobičnog.
07:37
And we found that everything is normal.
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I našli smo da je sve normalno.
07:40
These stars are normal like the Sun. Age, everything was normal.
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Te zvezde su normalne kao Sunce. Starost, sve je bilo normalno.
07:43
So this is a mystery.
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To je dakle misterija.
07:45
It's one of the mysteries we still have, super flares.
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To je jedna od misterija koja i dalje nije razrešena, te super baklje.
07:48
And there are six or seven similar cases
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Postoji šest ili sedam sličnih slučajeva
07:51
reported in the literature.
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objavljenih u literaturi.
07:53
Now to go ahead with this,
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No, da nastavimo sa temom,
07:55
we really need to understand chemical evolution of the universe.
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stvarno treba da razumemo hemijsku evoluciju svemira.
07:59
It's very complicated. I don't really want you to
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Jako je komplikovana. Stvarno ne želim da
08:01
try to understand what is here.
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pokušate da razumete šta je ovde.
08:05
(Laughter)
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(Smeh)
08:06
But it's to show you how complicated is the whole story
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Ovo je da vam pokažem koliko je cela priča
08:09
of the production of chemical elements.
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o proizvodnji hemijskih elemenata komplikovana.
08:11
You have two channels --
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Postoje dva izvora -
08:13
the massive stars and low-mass stars --
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masivne zvezde i zvezde male mase -
08:15
producing and recycling matter and chemical elements in the universe.
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koje proizvode i recikliraju materiju i hemijske elemente u svemiru.
08:18
And doing this for 14 billion years,
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Nakon 14 milijardi godina,
08:21
we end up with this picture,
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na kraju dobijamo ovakvu sliku.
08:23
which is a very important graph,
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Ovo je vrlo važan grafik,
08:25
showing relative abundances of chemical elements
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koji pokazuje relativno izobilje hemijskih elemenata
08:28
in sun-like stars
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u zvezdama sličnim Suncu
08:30
and in the interstellar medium.
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i u međuzvezdanom mediju.
08:33
So which means that it's really impossible
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Što dakle znači da je stvarno nemoguće
08:35
to find an object where you find about 10 times more sulfur than silicon,
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pronaći objekte gde se može naći oko 10 puta više sumpora od silicijuma,
08:40
five times more calcium than oxygen. It's just impossible.
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pet puta više kalcijuma nego kiseonika.To je jednostavno nemoguće.
08:44
And if you find one, I will say that
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A ako nađete nešto takvo, reći ću vam da
08:46
this is something related to SETI,
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je to nešto povezano sa SETI-jem,
08:49
because naturally you can't do it.
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jer ne možete to da nadjete.
08:53
Doppler Effect is something very important
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Doplerov efekat je nešto veoma važno
08:55
from fundamental physics.
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za fundamentalnu fiziku.
08:57
And this is related to the change of the frequency
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Ovo je povezano sa promenom frekvencije
08:59
of a moving source.
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izvora koji se kreće.
09:01
The Doppler Effect is used to discover extrasolar planets.
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Doplerov efekat je korišćen za otkrivanje ekstrasolarnih planeta.
09:06
The precision which we need
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Neophodna preciznost
09:08
to discover a Jupiter-like planet
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da bi se otkrile planete poput Jupitera
09:10
around a sun-like star
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koji kruži oko zvezde poput Sunca
09:12
is something like 28.4 meters per second.
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je približno 28,4 metara u sekundi.
09:16
And we need nine centimeters per second
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Treba nam devet centimetara u sekundi
09:18
to detect an Earth-like planet.
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da bismo otkrili planetu poput Zemlje.
09:21
This can be done with the future spectrographs.
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To će se moći uraditi spektrografima u budućnosti.
09:24
I, myself, I'm actually involved in the team
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Ja, lično, sam deo tima
09:28
which is developing a CODEX,
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koji razvija CODEX,
09:30
high resolution, future generation spectrograph
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visoko rezolucioni spektrograf nove generacije.
09:32
for the 42 meter E-ELT telescope.
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za 42 metarski E-ELT teleskop.
09:36
And this is going to be an instrument
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Ovo će biti instrument
09:39
to detect Earth-like planets
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za otkrivanje planeta poput Zemlje
09:41
around sun-like stars.
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oko zvezda nalik Suncu.
09:43
It is an amazing tool called astroseismology
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To je fascinantan aparat nazvan astroseizmologija
09:46
where we can detect sound waves
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pomoću kojeg možemo otkriti zvučne talase
09:49
in the atmospheres of stars.
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u zvezdanim atmosferama.
09:51
This is the sound of an Alpha Cen.
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Ovo je zvuk Alfa Kentaurija.
09:54
We can detect sound waves
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Možemo detektovati zvučne talase
09:56
in the atmospheres of sun-like stars.
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u atmosferama zvezda sličnim Suncu.
09:58
Those waves have frequencies
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Ti talasi imaju frekvencije
10:01
in infrasound domain, the sound actually nobody knows, domain.
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u infrazvučnom domenu, domenu koji niko ne poznaje.
10:05
Coming back to the most important question,
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Vratimo se na najvažnije pitanje,
10:07
"Is there anybody out there?"
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"Ima li koga tamo?"
10:09
This is closely related
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To je blisko povezano
10:11
to tectonic and volcanic activity of planets.
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sa tektonskim i vulkanskim aktivnostima planeta.
10:15
Connection between life
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Veza izmedju života
10:17
and radioactive nuclei
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i radioaktivnih jezgara
10:19
is straightforward.
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je jednostavna.
10:21
No life without tectonic activity,
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Nema života bez tektonske aktivnosti,
10:24
without volcanic activity.
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bez vulkanske aktivnosti.
10:26
And we know very well that geothermal energy
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Jako dobro znamo da geotermalna energija
10:28
is mostly produced by decay of uranium, thorium, and potassium.
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uglavnom nastaje raspadanjem urana, torijuma i kalijuma.
10:33
How to measure, if we have planets
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Kako to izmeriti, ako imamo planete
10:37
where the amount of those elements is small,
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gde je količina tih elemenata mala,
10:41
so those planets are tectonically dead,
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te su te planete tektonski mrtve,
10:44
there cannot be life.
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tamo ne može biti života.
10:46
If there is too much uranium or potassium or thorium,
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Ako je previše urana ili kalijuma ili torijuma,
10:49
probably, again, there would be no life.
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verovatno, opet, ne bi bilo života.
10:52
Because can you imagine everything boiling?
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Možete li zamisliti da sve ključa?
10:54
It's too much energy on a planet.
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To je znak previše energije na planeti.
10:56
Now, we have been measuring abundance
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Sada, merili smo količinu
10:58
of thorium in one of the stars with extrasolar planets.
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torijuma u jednoj zvezdi sa ekstrasolarnim planetama.
11:02
It's exactly the same game. A very tiny feature.
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To je potpuno ista igra. Veoma slaba osobina.
11:06
We are actually trying to measure this profile
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Mi zapravo pokušavamo da izmerimo ovaj profil
11:08
and to detect thorium.
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i detektujemo torijum.
11:10
It's very tough. It's very tough.
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To je veoma teško. To je veoma teško.
11:12
And you have to, first you have to convince yourself.
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Prvo morate ubediti sebe.
11:14
Then you have to convince your colleagues.
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Onda morate ubediti svoje kolege.
11:16
And then you have to convince the whole world
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A, onda morate ubediti ostatak sveta
11:19
that you have actually detected something like this
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da ste zapravo detektovali nešto poput toga
11:22
in the atmosphere of an extrasolar planet
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u atmosferi ekstrasolarne planete
11:24
host star somewhere in 100 parsec away from here.
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koja kruži oko zvezde na sto parseka odavde.
11:27
It's really difficult.
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Stvarno je teško.
11:29
But if you want to know about a life on extrasolar planets,
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Ali ako želite znati nešto o životu na ekstrasolarnim planetama,
11:34
you have to do this job.
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morate uraditi taj posao.
11:36
Because you have to know how much of radioactive element you have
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Jer morate znati koliko imate radioaktivnih elemenata
11:39
in those systems.
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u tim sistemima.
11:41
The one way to discover about aliens
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Jedan način da saznate nešto o vanzemaljcima
11:44
is to tune your radio telescope and listen to the signals.
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je da uključite svoj radio-teleskop i slušate signale.
11:48
If you receive something interesting,
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Ako primite neke interesantne,
11:51
well that's what SETI does actually,
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to je ono što SETI zapravo radi,
11:53
what SETI has been doing for many years.
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što je SETI radio mnogo godina.
11:56
I think the most promising way
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Mislim da je jedan od puteva sa najviše izgleda za uspeh
11:58
is to go for biomarkers.
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da tražimo biomarkere.
12:01
You can see the spectrum of the Earth, this Earthshine spectrum,
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Možete videti spektar Zemlje, spektar Zemljinog sjaja
12:04
and that is a very clear signal.
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i to je veoma čist signal.
12:07
The slope which is coming, which we call a Red Edge,
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Kriva koju dobijamo, koju zovemo Crvenom krivom,
12:10
is a detection of vegetated area.
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predstavlja detektovanu površinu, pokrivenu vegetacijom.
12:14
It's amazing that we can detect vegetation
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Neverovatno je da možemo detektovati vegetaciju
12:18
from a spectrum.
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na osnovu spektra.
12:20
Now imagine doing this test
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Sada zamislite da radite taj test
12:22
for other planets.
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za druge planete.
12:25
Now very recently, very recently,
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Jako nedavno, jako nedavno,
12:28
I'm talking about last six, seven, eight months,
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govorim o poslednjih šest, sedam, osam meseci
12:31
water, methane, carbon dioxide
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voda, metan, ugljen-dioksid
12:35
have been detected in the spectrum
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su detektovani u spektru
12:37
of a planet outside the solar system.
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planete van Sunčevog sistema.
12:40
It's amazing. So this is the power of spectroscopy.
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To je neverovatno. To je dakle moć spektroskopije.
12:44
You can actually go and detect
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Možete detektovati
12:47
and study a chemical composition of planets
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i proučavati hemijski sastav planeta
12:50
far, far, far from solar system.
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daleko, daleko, daleko od Sunčevog sistema.
12:53
We have to detect oxygen or ozone
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Moramo detektovati kiseonik ili ozon
12:56
to make sure that we have all necessary conditions
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da bismo bili sigurni da imamo sve neophodne uslove
12:59
to have life.
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za život.
13:03
Cosmic miracles are something
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Kosmička čuda su nešto
13:05
which can be related to SETI.
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što se može povezati sa SETI-jem.
13:07
Now imagine an object, amazing object,
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Sada zamislite objekat, neverovatan objekat,
13:09
or something which we cannot explain
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ili nešto što ne možemo objasniti
13:11
when we just stand up and say,
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kada samo ustanemo i kažemo,
13:13
"Look, we give up. Physics doesn't work."
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"Pogledajte, odustajemo. Fizika ne funkcioniše."
13:15
So it's something which you can always refer to SETI and say,
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To je, dakle, nešto što uvek možete povezati sa SETI-jem i reći,
13:18
"Well, somebody must be doing this, somehow."
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"Pa, neko mora da radi ovo, nekako."
13:23
And with the known physics etc,
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I sa poznatom fizikom itd.
13:25
it's something actually which has been pointed out
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to je nešto što je naglasio
13:27
by Frank Drake,
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Frenk Drejk,
13:29
many years ago, and Shklovsky.
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pre mnogo godina i Šklovski,
13:31
If you see, in the spectrum of a planet host star,
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Ako u spektru planete koja kruži oko zvezde
13:34
if you see strange chemical elements,
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vidite strane hemijske elemente,
13:38
it can be a signal from a civilization
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to može biti signal neke civilizacije
13:41
which is there and they want to signal about it.
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koja je tamo i koja želi to da pokaže.
13:44
They want to actually signal their presence
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Oni žele da pokažu svoju prisutnost
13:48
through these spectral lines,
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preko ovih spektralnih linija,
13:50
in the spectrum of a star, in different ways.
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u spektru zvezde, na različite načine.
13:53
There can be different ways doing this.
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Postoji mnogo načina da se to uradi.
13:55
One is, for instance, technetium
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Jedan je, na primer, tehnecijum
13:57
is a radioactive element
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to je radioaktivan element
13:59
with a decay time of 4.2 million years.
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sa periodom poluraspada od 4,2 miliona godina.
14:02
If you suddenly observe technetium
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Ako ste slučajno posmatrali tehnecijum
14:05
in a sun-like star,
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u zvezdi nalik Suncu,
14:07
you can be sure that somebody has put this
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možete biti sigurni da je neko stavio taj
14:09
element in the atmosphere,
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element u atmosferu,
14:11
because in a natural way it is impossible to do this.
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jer prirodnim putem je to nemoguće učiniti.
14:15
Now we are reviewing the spectra of about
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Mi sada pregledamo spektar nekih
14:18
300 stars with extrasolar planets.
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tri stotine zvezda sa ekstrasolarnim planetama.
14:21
And we are doing this job since 2000
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Mi taj posao radimo od 2000.
14:25
and it's a very heavy project.
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i to je veoma težak projekat.
14:28
We have been working very hard.
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Radili smo jako naporno.
14:30
And we have some interesting cases,
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I imamo par zanimljivih slučajeva,
14:34
candidates, so on, things which we can't really explain.
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kandidata, stvari koje ne možemo zapravo da objasnimo.
14:38
And I hope in the near future
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I nadam se da ćemo u bližoj budućnosti
14:41
we can confirm this.
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moći to da potvrdimo.
14:43
So the main question: "Are we alone?"
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Tako da odgovor na glavno pitanje: "Da li smo sami?"
14:45
I think it will not come from UFOs.
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neće doneti NLO.
14:48
It will not come from radio signals.
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Neće nam ga dati radio signali.
14:52
I think it will come from a spectrum like this.
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Mislim da će doći od spektra sličnog ovom.
14:56
It is the spectrum of a planet like Earth,
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To je spektar planete nalik Zemlji,
15:01
showing a presence of nitrogen dioxide,
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koji pokazuje prisustvo azot-dioksida,
15:04
as a clear signal of life,
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kao čistog signala života,
15:07
and oxygen and ozone.
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i kiseonik i ozon.
15:09
If, one day, and I think it will be
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Ako, jednog dana, a verujem da hoće
15:11
within 15 years from now, or 20 years.
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za 15 godina od danas ili 20 godina,
15:14
If we discover a spectrum like this
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otkrijemo spektar poput ovog
15:17
we can be sure that there is life on that planet.
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možemo biti sigurni da na toj planeti postoji život.
15:19
In about five years we will discover
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Za jedno pet godina ćemo pronaći
15:22
planets like Earth, around sun-like stars,
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planete poput Zemlje, oko zvezda poput Sunca,
15:25
the same distance as the Earth from the Sun.
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na istoj udaljenosti kao udaljenosti Zemlje od Sunca.
15:28
It will take about five years.
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Trebaće oko pet godina.
15:30
And then we will need another 10, 15 years
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I onda će nam trebati dodatnih 10, 15 godina
15:32
with space projects
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sa svemirskim projektima da bismo dobili
15:34
to get the spectra of Earth-like planets like the one I showed you.
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spektre zemljolikih planeta poput onog kojeg sam vam pokazao.
15:37
And if we see the nitrogen dioxide
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I ako vidimo azot dioksid
15:39
and oxygen,
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i kiseonik,
15:41
I think we have the perfect E.T.
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mislim da ćemo imati odličnog E.T.-a
15:43
Thank you very much.
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Hvala vam mnogo.
15:45
(Applause)
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(Aplauz)
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