TEDGlobal 2009
Garik Israelian: How spectroscopy could reveal alien life
Garik Israelian: Što je unutar zvijezde?
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Garik Israelian je spektroskopičar koji proučava spektre koji zvijezde emitiraju kako bi saznao od čega su napravljene i kako se ponašaju. Ovo je rijedak i pristupačan uvid u ovu disciplinu, koja je blizu otkriča planeta sposobnim za 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 vrlo težak zadatak.
00:21
I'm a spectroscopist.
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Ja sam spektroskopičar.
00:24
I have to talk about astronomy without showing you
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Moram govoriti o astronomiji bez da vam prikažem
00:26
any single image of nebulae or galaxies, etc.
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bilo koju sliku maglice ili galaksija, itd.
00:30
because my job is spectroscopy.
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jer moj posao je spektroskopija.
00:32
I never deal with images.
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Ja nikada ne baratam sa slikama.
00:35
But I'll try to convince you
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Ali ću vas pokušati uvjeriti
00:37
that spectroscopy is actually something which can
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da je spektroskopija zapravo nešto što može
00:39
change this world.
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promijeniti ovaj svijet.
00:42
Spectroscopy can probably answer the question,
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Spektroskopija vjerojatno može odgovoriti na pitanje,
00:45
"Is there anybody out there?"
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"Ima li ikoga tamo vani?"
00:47
Are we alone? SETI.
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Jesmo li sami? SETI.
00:49
It's not very fun to do spectroscopy.
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Nije baš zabavno baviti se spektroskopijom.
00:52
One of my colleagues in Bulgaria,
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Jedan od mojih kolega u Bugarskoj,
00:54
Nevena Markova, spent about 20 years
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Neviana Markova, provela je oko 20 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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posvećena samo toj temi.
01:03
Can you imagine? Day and night, thinking,
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Možete li si to zamisliti? Danju i noću, razmišljati,
01:05
observing, the same star for 20 years
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promatrati, istu zvijezdu kroz 20 godina
01:08
is incredible.
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je nevjerojatno.
01:10
But we are crazy. We do these things.
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No mi smo ludi. Mi radimo te stvari.
01:12
(Laughter)
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(Smijeh)
01:14
And I'm not that far.
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A ja nisam tako daleko.
01:16
I spent about eight months working on these profiles.
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Proveo sam osam mjeseci radeći na tim profilima.
01:19
Because I've noticed
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Jer sam primijetio
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 središnjih zvijezda planeta.
01:25
And I thought, well maybe there is Lithium-6 in this star,
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Pomislio sam, možda postoji litij-6 u ovoj zvijezdi,
01:29
which is an indication that this star
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što je pokazatelj da je ova zvijezda
01:31
has swallowed a planet.
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progutala planet.
01:33
Because apparently you can't have this fragile isotope
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Jer očito se ne može imati ovaj krhki izotop
01:36
of Lithium-6 in the atmospheres of sun-like stars.
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litija-6 u atmosferi zvijezda nalik Suncu.
01:40
But you have it in planets and asteroids.
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Ali postoji u planetima i asteroidima.
01:43
So if you engulf planet or large number of asteroids,
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Dakle, ako ste progutali planet ili velik broj asteroida,
01:49
you will have this Lithium-6 isotope
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imat ćete ovaj izotop litija-6
01:52
in the spectrum of the star.
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u spektru zvijezde.
01:54
So I invested more than eight months
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Tako sam uložio više od osam mjeseci
01:58
just studying the profile of this star.
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samo u proučavanje profila linije litija ove zvijezde.
02:00
And actually it's amazing,
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A to je zapravo nevjerojatno,
02:02
because I got phone calls from many reporters asking,
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jer sam dobio telefonske pozive mnogih novinara ispitujući,
02:04
"Have you actually seen the planet going into a star?"
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"Jeste li zapravo vidjeli kako planet ide u zvijezdu?"
02:07
Because they thought that if you are having a telescope,
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Jer su mislili da, ako imate teleskop,
02:11
you are an astronomer so what you are doing
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vi ste astronom pa to što radite
02:13
is actually looking in a telescope.
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je zapravo gledanje u teleskop.
02:15
And you might have seen the planet going into a star.
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I možda ste vidjeli kako planet ide u zvijezdu.
02:19
And I was saying, "No, excuse me.
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Na što sam odgovorio: "Ne, oprostite.
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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(Smijeh)
02:24
It's just incredible. Because nobody understood really.
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To je nevjerojatno. Jer nitko nije zapravo razumio.
02:27
I bet that there were very few people
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Mogu se kladiti da je bilo vrlo malo ljudi
02:29
who really understood what I'm talking about.
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koji su zaista razumjeli o čemu pričam.
02:32
Because this is the indication that the planet went into the star.
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Jer ovo je pokazatelj da je planet otišao u zvijezdu.
02:36
It's amazing.
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To je nevjerojatno.
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 Floyd-om već u 1973.
02:47
(Laughter)
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(Smijeh)
02:48
Because they actually said that
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Jer su oni 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 trebate je vrijeme i novac
02:57
to make your spectrograph.
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kako bi napravili svoj spektrograf.
02:59
This is the number one high resolution,
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Ovo je broj jedan visoke rezolucije,
03:02
most precise spectrograph on this planet, called HARPS,
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najprecizniji spektrograf na ovom planetu, 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 valova
03:09
in the atmospheres of stars.
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u atmosferama zvijezda.
03:11
How we get spectra?
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Kako dobivamo spektar?
03:14
I'm sure most of you know from school physics
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Siguran sam da većina od vas to zna još iz školske fizike
03:17
that it's basically splitting a white light
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da je to u osnovi cijepanje bijelog svijetla
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 tekuću vruću masu,
03:26
it will produce something which we call a continuous spectrum.
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to će proizvesti nešto što mi nazivamo kontinuirani spektar.
03:30
A hot gas is producing emission lines only,
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Vrući plin proizvodi samo emisijske 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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A ako se stavi hladni plin ispred
03:39
hot source,
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vrućeg izvora,
03:41
you will see certain patterns
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vidjeti ćete određene uzorke
03:43
which we call absorption lines.
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koje nazivamo apsorpcijskim linijama.
03:45
Which is used actually to identify chemical elements
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Koji se zapravo koriste za identifikaciju kemijskih elemenata
03:48
in a cool matter,
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u hladnoj tvari,
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which is absorbing exactly at those frequencies.
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koji upija upravo na tim frekvencijama.
03:53
Now, what we can do with the spectra?
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Sada, što možemo učiniti sa tim spektrima,
03:56
We can actually study line-of-sight velocities
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zapravo možemo proučavati pravocrtnu brzinu
03:59
of cosmic objects.
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svemirskih objekata.
04:01
And we can also study chemical composition
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A možemo također proučavati i kemijski sastav
04:04
and physical parameters of stars,
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i fizikalne parametre zvijezda,
04:06
galaxies, nebulae.
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galaksija, maglica.
04:08
A star is the most simple object.
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Zvijezda je najjednostavniji objekt.
04:10
In the core, we have thermonuclear reactions going on,
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U jezgri se zbiva termonuklearna reakcija
04:14
creating chemical elements.
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stvaranja kemijskih elemenata.
04:16
And we have a cool atmosphere.
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A imamo i hladnu atmosferu.
04:18
It's cool for me.
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To je hladno za mene.
04:20
Cool in my terms is three or four or five thousand degrees.
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Hladno, u mom pogledu, je tri ili četiri ili pet tisuća stupnjeva.
04:24
My colleagues in infra-red astronomy
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Moji 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 je za mene 5000 stupnjeva prilično hladno.
04:36
(Laughter)
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(Smijeh)
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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a oko 15 posto ovih linija još uvijek nije identificirano.
04:47
It is amazing. So we are in the 21st century,
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To je nevjerojatno. Dakle, mi smo u 21. stoljeću,
04:50
and we still cannot properly understand
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a još uvijek ne razumijemo pošteno
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 se moramo nositi sa
04:56
just one tiny, weak spectral line
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samo jednom malenom, slabom spektralnom linijom
04:59
to measure the composition of that chemical element in the atmosphere.
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za mjerenje sastava tog kemijskog elementa u atmosferi.
05:03
For instance, you see the spectral line of the gold
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Na primjer, vidite jedinu spektralnu liniju zlata
05:06
is the only spectral line in the spectrum of the Sun.
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u spektru Sunca.
05:09
And we use this weak feature
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A mi koristimo ovu slabu značajku
05:11
to measure the composition
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za mjerenje sastava
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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A ovo je trenutačno posao u tijeku.
05:19
We have been dealing with a similarly very weak feature,
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Već smo se bili bavili sličnim, vrlo slabim značajkama,
05:23
which belongs to osmium.
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koje pripadaju osmiju.
05:25
It's a heavy element produced in thermonuclear
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To je težak element proizveden u termonuklearnim
05:29
explosions of supernovae.
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eksplozijama supernova.
05:31
It's the only place where you can produce, actually, osmium.
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To je jedino mjesto gdje možete, zapravo, proizvesti osmij.
05:34
Just comparing the composition of osmium
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Samo uspoređujući sastav osmija
05:38
in one of the planet host stars,
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u jednoj od središnjih zvijezda planeta,
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, čak pretpostavljamo da su možda
05:47
supernova explosions trigger formations of planets and stars.
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eksplozije supernova okidač za stvaranje planeta i zvijezda.
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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Neki mi je dan kolega sa Berkeley-a,
05:56
Gibor Basri, emailed me
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Gibor Basri, poslao e-poštom
05:58
a very interesting spectrum,
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vrlo zanimljiv spektar,
06:00
asking me, "Can you have a look at this?"
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pitajući me, "Možeš li baciti pogled na ovo?"
06:02
And I couldn't sleep, next two weeks,
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Nisam mogao spavati, iduća dva tjedna,
06:06
when I saw the huge amount of oxygen
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vidjevši toliko veliku količinu kisika
06:09
and other elements in the spectrum of the stars.
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i ostalih elemenata u spektru zvijezde.
06:11
I knew that there is nothing like that observed in the galaxy.
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Znao sam da ništa slično nije uočeno u galaksiji.
06:15
It was incredible. The only conclusion we could make from this
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Bilo je nevjerojatno. Jedini zaključak koji smo mogli iz toga izvući
06:19
is clear evidence that there was a supernova explosion
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je jasan dokaz da je došlo do eksplozije supernove
06:22
in this system, which polluted the atmosphere
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u tom sustavu, koja je onečistila atmosferu
06:25
of this star.
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ove zvijezde.
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 sustavu,
06:31
which is still there with a mass of about
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koji je još uvijek 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 eksplozijom supernova.
06:42
My colleagues, comparing composition of chemical elements
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Moji kolege, uspoređujući sastav kemijskih elemenata
06:44
in different galactic stars,
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u različitim zvijezdama galaksija
06:46
actually discovered alien stars in our galaxy.
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zapravo otkrivaju strane zvijezde u našoj galaksiji.
06:50
It's amazing that you can go so far
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Nevjerojatno je da možete ići tako daleko
06:53
simply studying the chemical composition of stars.
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jednostavno proučavajući kemijski sastav zvijezda.
06:57
They actually said that one of the stars you see in the spectra
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Oni su zapravo ustvrdili da je jedna od zvijezda koju vidite u spektru
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. Znamo za to.
07:06
And sometimes they just capture stars.
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I ponekad one naprosto otmu zvijezde.
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 vrlo 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 tisuće milijuna puta
07:22
more powerful than those we see in the Sun.
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moćnija od onih koje vidimo na Suncu.
07:24
In one of the binary stars in our galaxy
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U jednoj od binarnih zvijezda u našoj galaksiji
07:27
called FH Leo,
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zvanoj FH Leo,
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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A kasnije smo se okrenuli proučavanju spektralnih linija
07:35
to see is there anything strange with these objects.
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kako bi vidjeli da li se nešto čudno desilo s tim objektom.
07:37
And we found that everything is normal.
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No ustanovili smo da je sve normalno.
07:40
These stars are normal like the Sun. Age, everything was normal.
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Te zvijezde su normalne poput Sunca. Starost, sve je bilo normalno.
07:43
So this is a mystery.
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Dakle, ovo je misterija.
07:45
It's one of the mysteries we still have, super flares.
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To je jedna od misterija koje još uvijek imamo, super baklje.
07:48
And there are six or seven similar cases
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I 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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Da krenemo dalje sa ovime,
07:55
we really need to understand chemical evolution of the universe.
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mi doista trebamo razumjeti kemijsku evoluciju svemira.
07:59
It's very complicated. I don't really want you to
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To je vrlo komplicirano. Zapravo i ne želim
08:01
try to understand what is here.
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da pokušate razumjeti što je ovdje.
08:05
(Laughter)
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(Smijeh)
08:06
But it's to show you how complicated is the whole story
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Nego ovo je da vam predočim koliko je komplicirana ova cijela priča
08:09
of the production of chemical elements.
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o proizvodnji kemijskih elemenata.
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 zvijezde i zvijezde male mase --
08:15
producing and recycling matter and chemical elements in the universe.
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koji proizvode i recikliraju materiju i kemijske elemente u svemiru.
08:18
And doing this for 14 billion years,
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I radeći to 14 milijardi godina,
08:21
we end up with this picture,
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na kraju dobivamo ovu sliku.
08:23
which is a very important graph,
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Ovo je vrlo važan graf,
08:25
showing relative abundances of chemical elements
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koji prikazuje relativnu brojnost kemijskih elemenata
08:28
in sun-like stars
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u Suncu sličnim zvijezdama
08:30
and in the interstellar medium.
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i u među-zvjezdanom 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 objekt gdje se može naći oko 10 puta više sumpora od silicija,
08:40
five times more calcium than oxygen. It's just impossible.
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pet puta više kalcija nego kisika. To je stvarno nemoguće.
08:44
And if you find one, I will say that
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A ako nađete jedan ja ću reći da
08:46
this is something related to SETI,
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je to povezano sa SETI.
08:49
because naturally you can't do it.
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Jer prirodno to nije moguće.
08:53
Doppler Effect is something very important
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Dopplerov efekt je nešto jako važno
08:55
from fundamental physics.
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iz temeljne fizike.
08:57
And this is related to the change of the frequency
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A povezano je sa promjenom frekvencije
08:59
of a moving source.
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pokretnog izvora.
09:01
The Doppler Effect is used to discover extrasolar planets.
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Dopplerov efekt se koristi za otkrivanje ekstrasolarnih planeta.
09:06
The precision which we need
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Preciznost koja nam je potrebna
09:08
to discover a Jupiter-like planet
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kako bi otkrili planet sličan Jupiteru
09:10
around a sun-like star
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oko Suncu slične zvijezde
09:12
is something like 28.4 meters per second.
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je nešto oko 28,4 metara u sekundi.
09:16
And we need nine centimeters per second
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I trebamo devet centimetra u sekundi
09:18
to detect an Earth-like planet.
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kako bi otkrili planet sličan Zemlji.
09:21
This can be done with the future spectrographs.
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To može biti učinjeno s budućim spektrografima.
09:24
I, myself, I'm actually involved in the team
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Ja, osobno, sam zapravo dijelom 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 rezolucijski 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 zvijezda nalik Suncu.
09:43
It is an amazing tool called astroseismology
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To je nevjerojatan alat zvan astroseizmologija
09:46
where we can detect sound waves
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pomoću kojeg možemo otkriti zvučne valove
09:49
in the atmospheres of stars.
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u atmosferi zvijezda.
09:51
This is the sound of an Alpha Cen.
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Ovo je zvuk Alpha Centauri.
09:54
We can detect sound waves
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Možemo otkriti zvučne valove
09:56
in the atmospheres of sun-like stars.
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u atmosferi zvijezda nalik Suncu.
09:58
Those waves have frequencies
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Ti valovi imaju frekvenciju
10:01
in infrasound domain, the sound actually nobody knows, domain.
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u podzvučnom području, domeni zvuka koji zapravo nitko ne zna.
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 ikoga tamo vani?"
10:09
This is closely related
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Ovo je usko povezano
10:11
to tectonic and volcanic activity of planets.
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sa tektonskom i vulkanskom aktivnošću planeta.
10:15
Connection between life
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Veza između života
10:17
and radioactive nuclei
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i radioaktivnih jezgri
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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A znamo jako dobro da geotermalna energija
10:28
is mostly produced by decay of uranium, thorium, and potassium.
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uglavnom nastaje raspadom urana, torija i kalija.
10:33
How to measure, if we have planets
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Kako to izmjeriti, ako imamo planete
10:37
where the amount of those elements is small,
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gdje je količina tih elemenata malena,
10:41
so those planets are tectonically dead,
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tako da su ti planeti tektonski gledajući mrtvi,
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 kalija ili torija,
10:49
probably, again, there would be no life.
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vjerojatno, opet, ne bi bilo života.
10:52
Because can you imagine everything boiling?
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Možete li zamisliti kako sve ključa?
10:54
It's too much energy on a planet.
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To je previše energije na planeti.
10:56
Now, we have been measuring abundance
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Sada, mjerili smo obilje
10:58
of thorium in one of the stars with extrasolar planets.
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torija u jednoj od zvijezda s ekstrasolarnim planetima.
11:02
It's exactly the same game. A very tiny feature.
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To je potpuno ista igra. Vrlo malena značajka.
11:06
We are actually trying to measure this profile
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Mi zapravo pokušavamo izmjeriti ovaj profil
11:08
and to detect thorium.
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i otkriti torij.
11:10
It's very tough. It's very tough.
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To je vrlo teško. To je vrlo teško.
11:12
And you have to, first you have to convince yourself.
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A morate... prvo morate uvjeriti samoga sebe.
11:14
Then you have to convince your colleagues.
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Tada morati uvjeriti i svoje kolege.
11:16
And then you have to convince the whole world
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A onda morate uvjeriti i cijeli svijet
11:19
that you have actually detected something like this
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da ste zapravo otkrili nešto poput ovoga
11:22
in the atmosphere of an extrasolar planet
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u atmosferi središnje zvijezde ekstrasolarnog
11:24
host star somewhere in 100 parsec away from here.
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planeta, negdje oko 100 parseka odavdje.
11:27
It's really difficult.
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To je stvarno teško.
11:29
But if you want to know about a life on extrasolar planets,
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Ali ako želite znati o životu na ekstrasolarnim planetima
11:34
you have to do this job.
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morate raditi ovaj posao.
11:36
Because you have to know how much of radioactive element you have
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Jer morate znati koliko radioaktivnog elementa imate
11:39
in those systems.
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u tim sustavima.
11:41
The one way to discover about aliens
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Jedan od načina kako otkriti vanzemaljce
11:44
is to tune your radio telescope and listen to the signals.
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je da podesite svoj radio teleskop i slušate signale.
11:48
If you receive something interesting,
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Ako dobijete nešto zanimljivo,
11:51
well that's what SETI does actually,
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to je zapravo ono što SETI i radi,
11:53
what SETI has been doing for many years.
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što je SETI radio godinama.
11:56
I think the most promising way
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Smatram da najviše obećava
11:58
is to go for biomarkers.
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potraga za biomarkerima.
12:01
You can see the spectrum of the Earth, this Earthshine spectrum,
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Možete vidjeti spektar Zemlje, ovaj Zemljin spektar,
12:04
and that is a very clear signal.
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a ovo je vrlo jasan signal.
12:07
The slope which is coming, which we call a Red Edge,
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Krivulja koja dolazi, koju mi zovemo Red Edge,
12:10
is a detection of vegetated area.
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predstavlja detekciju područja vegetacije.
12:14
It's amazing that we can detect vegetation
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Nevjerojatno je da možemo otkriti vegetaciju
12:18
from a spectrum.
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iz spektra.
12:20
Now imagine doing this test
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Sada zamislite ovaj test
12:22
for other planets.
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nad drugim planetima
12:25
Now very recently, very recently,
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Nedavno, vrlo nedavno,
12:28
I'm talking about last six, seven, eight months,
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govorim o posljednjih šest, sedam, osam mjeseci,
12:31
water, methane, carbon dioxide
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voda, metan, ugljični dioksid
12:35
have been detected in the spectrum
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bili su otkriveni u spektru
12:37
of a planet outside the solar system.
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planeta izvan Sunčevog sustava.
12:40
It's amazing. So this is the power of spectroscopy.
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Nevjerojatno. Dakle, ovo je moć spektroskopije.
12:44
You can actually go and detect
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Možete zapravo ići i otkriti
12:47
and study a chemical composition of planets
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i studirati kemijski sastav planeta
12:50
far, far, far from solar system.
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daleko, daleko, daleko od sunčevog sustava.
12:53
We have to detect oxygen or ozone
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Moramo otkriti kisik ili ozon
12:56
to make sure that we have all necessary conditions
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kako bi bili sigurni da imamo sve potrebne uvjete
12:59
to have life.
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za postojanje života.
13:03
Cosmic miracles are something
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Svemirska čuda su nešto
13:05
which can be related to SETI.
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što može biti povezano sa SETI.
13:07
Now imagine an object, amazing object,
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Sada zamislite objekt, nevjerojatan objekt,
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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kad možemo samo ustati i reći:
13:13
"Look, we give up. Physics doesn't work."
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"Gle, mi odustajemo. Fizika ne radi."
13:15
So it's something which you can always refer to SETI and say,
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To je nešto što uvijek možete pripisati SETI i reći,
13:18
"Well, somebody must be doing this, somehow."
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"Pa, mora da ovo netko radi, na neki način."
13:23
And with the known physics etc,
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A s poznatom fizikom itd.,
13:25
it's something actually which has been pointed out
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to je zapravo nešto što je istaknuo
13:27
by Frank Drake,
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Frank Drake,
13:29
many years ago, and Shklovsky.
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prije mnogo godina [nejasno].
13:31
If you see, in the spectrum of a planet host star,
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Ako vidite, u spektru središnje zvijezde planeta,
13:34
if you see strange chemical elements,
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ako vidite strane kemijske elemente,
13:38
it can be a signal from a civilization
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to može biti signal civilizacije
13:41
which is there and they want to signal about it.
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koja je tamo i oni to žele signalizirati.
13:44
They want to actually signal their presence
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Oni zapravo žele signalizirati svoju prisutnost
13:48
through these spectral lines,
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kroz te spektralne linije,
13:50
in the spectrum of a star, in different ways.
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u spektru zvijezde, na različite načine.
13:53
There can be different ways doing this.
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To se može učiniti na različite načine.
13:55
One is, for instance, technetium
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Jedan od njih je na primjer tehnicij,
13:57
is a radioactive element
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radioaktivni element
13:59
with a decay time of 4.2 million years.
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s vremenom poluraspada od oko 4,2 milijuna godina.
14:02
If you suddenly observe technetium
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Ako iznenada pronađete tehnicij
14:05
in a sun-like star,
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u Suncu sličnoj zvijezdi,
14:07
you can be sure that somebody has put this
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možete biti sigurni da je netko 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 je na prirodan način to nemoguće učiniti.
14:15
Now we are reviewing the spectra of about
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Sada ispitujemo spektre od oko
14:18
300 stars with extrasolar planets.
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300 zvijezda s ekstrasolarnim planetima.
14:21
And we are doing this job since 2000
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Taj posao radimo još od 2000.
14:25
and it's a very heavy project.
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i to je vrlo težak projekt.
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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Imamo neke zanimljive slučajeve,
14:34
candidates, so on, things which we can't really explain.
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kandidate, itd., stvari koje zapravo ne možemo objasniti.
14:38
And I hope in the near future
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A nadam se da u bliskoj budućnosti
14:41
we can confirm this.
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možemo to i potvrditi.
14:43
So the main question: "Are we alone?"
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Dakle, glavno pitanje: "Jesmo li sami?"
14:45
I think it will not come from UFOs.
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Mislim da to neće doći od NLO-a.
14:48
It will not come from radio signals.
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Ona neće doći od radio signala.
14:52
I think it will come from a spectrum like this.
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Smatram da će doći iz spektra kao što je ovaj.
14:56
It is the spectrum of a planet like Earth,
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Ovo je spektar planete poput Zemlje
15:01
showing a presence of nitrogen dioxide,
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koji pokazuje prisustvo dušikovog oksida,
15:04
as a clear signal of life,
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kao jasan signal života,
15:07
and oxygen and ozone.
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i kisika i ozona.
15:09
If, one day, and I think it will be
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Ako, jednom, a mislim da će biti
15:11
within 15 years from now, or 20 years.
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unutar 15 godina od sada, ili 20 godina.
15:14
If we discover a spectrum like this
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Ako otkrijemo spektar kao što je ovaj
15:17
we can be sure that there is life on that planet.
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možemo biti sigurni da postoji život na tom planetu.
15:19
In about five years we will discover
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Unutar pet godina ćemo otkriti
15:22
planets like Earth, around sun-like stars,
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planete slične Zemlji, oko zvijezda nalik Suncu,
15:25
the same distance as the Earth from the Sun.
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na istoj udaljenosti kao što je Zemlja od Sunca.
15:28
It will take about five years.
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Potrajati će oko pet godina.
15:30
And then we will need another 10, 15 years
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A onda ćemo trebati još 10, 15 godina
15:32
with space projects
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sa svemirskim projektima
15:34
to get the spectra of Earth-like planets like the one I showed you.
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kako bi dobili spektre Zemlji sličnih planeta, poput onog koji sam vam pokazao.
15:37
And if we see the nitrogen dioxide
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I ako vidimo dušikov oksid
15:39
and oxygen,
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i kisik,
15:41
I think we have the perfect E.T.
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mislim da ćemo imati savršenog E.T.-a.
15:43
Thank you very much.
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Puno vam hvala
15:45
(Applause)
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(Pljesak)
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