Garik Israelian: What's inside a star?

47,516 views ・ 2009-10-01

TED


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Prevoditelj: Željko Babić Recezent: Zrinka Gattin
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,
03:50
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)
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