TEDGlobal 2009
Garik Israelian: How spectroscopy could reveal alien life
Garik Israelian: Šta je unutar zvezde?
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Garik Israelian je spektroskopičar koji proučava spektre koje emituju zvezde kako bi saznao od čega su napravljene i kako se ponašaju. Ovo je redak i pristupačan uvid u ovu disciplinu, koja je blizu otkrića planeta na kojima može nastati život.
Garik Israelian - Astrophysicist
Garik Israelian's stargazing on the Canary Islands has led to high-profile discoveries about space's big disasters -- including the first evidence that supernova explosions make black holes. Full bio
Garik Israelian's stargazing on the Canary Islands has led to high-profile discoveries about space's big disasters -- including the first evidence that supernova explosions make black holes. Full bio
Double-click the English transcript below to play the video.
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)
ABOUT THE SPEAKER
Garik Israelian - AstrophysicistGarik Israelian's stargazing on the Canary Islands has led to high-profile discoveries about space's big disasters -- including the first evidence that supernova explosions make black holes.
Why you should listen
Garik Israelian studies the spectral signatures of stars and other bodies as an astrophysicist at the Gran Telescopio Canarias, home of the world's largest optical-infrared telescope mirror, part of the Institute of Astrophysics on the Canary Islands. He has published more than 150 articles on topics such as extra-solar planets and black hole binary systems, and his observational work -- poring over the spectral data that points to the composition of distant stars -- has led to the discovery of a lithium signature that suggests Sun-sized stars gobble up their planets.
In 1999, Israelian led a collaboration that found the first observational evidence that supernova explosions are responsible for the formation of black holes. He's on the verge of announcing more big news. (And he is one of the astronomers whom Brian May, the guitarist of Queen, credits with persuading him to finish his PhD after 30 years as a rock star.)
Garik Israelian | Speaker | TED.com