Why neutrinos matter - Sílvia Bravo Gallart

Zašto su neutrini važni? - Silvija Bravo Galart (Sílvia Bravo Gallart)

Prevodilac: Tijana Mihajlović Lektor: Mile Živković

They're everywhere, but you will never see one.

Svuda su, ali nikada nećete videti neki.

Trillions of them are flying through you right this second,

Trilioni njih proleću kroz vas upravo ove sekunde,

but you can't feel them.

ali ne možete da ih osetite.

These ghost particles are called neutrinos and if we can catch them,

Ove fantomske čestice zovu se neutrini i ako bismo ih uhvatili,

they can tell us about the furthest reaches

mogle bi nam reći o najdaljim prostranstvima

and most extreme environments of the universe.

i najekstremnijim okruženjima u svemiru.

Neutrinos are elementary particles,

Neutrini su elementarne čestice,

meaning that they can't be subdivided into other particles the way atoms can.

što znači da se ne mogu dodatno deliti na druge delove na koje atomi mogu.

Elementary particles are the smallest known building blocks

Osnovne čestice najmanje su gradivne jedinice

of everything in the universe,

svega u svemiru,

and the neutrino is one of the smallest of the small.

a neutrino je najmanji među malima.

A million times less massive than an electron,

Milion puta manje mase nego elektron,

neutrinos fly easily through matter, unaffected by magnetic fields.

neutrini lako proleću kroz materiju, bez uticaja magnetnog polja na njih.

In fact, they hardly ever interact with anything.

U stvari, oni jedva da saobraćaju sa nečim.

That means that they can travel through the universe in a straight line

To znači da mogu putovati kroz svemir pravolinijski

for millions, or even billions, of years,

milionima, čak i milijardama godina,

safely carrying information about where they came from.

bezbedno prenoseći informacije o tome odakle su došli.

So where do they come from?

Pa, odakle dolaze?

Pretty much everywhere.

Skoro odasvud.

They're produced in your body from the radioactive decay of potassium.

Proizvode se u vašem telu kroz radioaktivno raspadanje kalijuma.

Cosmic rays hitting atoms in the Earth's atmosphere

Kosmički zraci koji udaraju u atome u Zemljinoj atmosferi

create showers of them.

stvaraju kiše neutrina.

They're produced by nuclear reactions inside the sun

Proizvode ih nuklearne reakcije unutar Sunca

and by radioactive decay inside the Earth.

i radioaktivno raspadanje unutar Zemlje.

And we can generate them in nuclear reactors

Možemo da ih proizvedemo i u nuklearnim reaktorima

and particle accelerators.

i akceleratorima čestica.

But the highest energy neutrinos are born far out in space

Međutim, neutrini sa navišom energijom rađaju se daleko u svemiru

in environments that we know very little about.

u okruženjima o kojima znamo veoma malo.

Something out there, maybe supermassive black holes,

Nešto što se tamo nalazi, možda supermasivne crne rupe,

or maybe some cosmic dynamo we've yet to discover,

ili možda nekakav svemirski generator koji tek treba da otkrijemo

accelerates cosmic rays to energies over a million times greater

ubrzava kosmičke zrake do energija koje su preko milion puta veće

than anything human-built accelerators have achieved.

od bilo čega što su akceleratori koje su ljudi izgradili postigli.

These cosmic rays, most of which are protons,

Ovi kosmički zraci, od kojih su većina protoni,

interact violently with the matter and radiation around them,

ostvaruju snažnu interakciju sa materijom i radijacijom oko sebe,

producing high-energy neutrinos,

proizvodeći visokoenergetske neutrine,

which propagate out like cosmic breadcrumbs

koji se razmnožavaju kao kosmičke mrvice

that can tell us about the locations

koje nam mogu doneti podatke o mestima

and interiors of the universe's most powerful cosmic engines.

i unutrašnjostima svemirskih najmoćnijih mašina,

That is, if we can catch them.

to jest, ako uspemo da ih uhvatimo.

Neutrinos' limited interactions with other matter

Ograničena interakcija neutrina sa drugom materijom

might make them great messengers,

mogla bi ih učiniti sjajnim glasnicima,

but it also makes them extremely hard to detect.

ali ih čini i jako teškim za uočavanje.

One way to do so is to put a huge volume of pure transparent material in their path

Jedan način da se to uradi je da se na njihov put postavi

ogromna zapremina čistog providnog materijala

and wait for a neutrino to reveal itself

i da se čeka da se neutrino otkrije

by colliding with the nucleus of an atom.

kroz sudaranje sa jezgrom atoma.

That's what's happening in Antarctica at IceCube,

To je ono što se dešava na Antartici u Ajskjubu,

the world's largest neutrino telescope.

najvećem svetskom teleskopu za neutrine.

It's set up within a cubic kilometer of ice

To je postavka u kubnom kilometru leda

that has been purified by the pressure

koja je pročišćena pritiskom nastalim od snega i leda

of thousands of years of accumulated ice and snow,

starih hiljadama godina,

to the point where it's one of the clearest solids on Earth.

dotle da je postao jedan od najčistijih čvrstih materijala na Zemlji.

And even though it's shot through with boreholes holding over 5,000 detectors,

Ipak, iako ima bušotine koje sadrže preko 5000 detektora,

most of the cosmic neutrinos racing through IceCube will never leave a trace.

većina kosmičkih neutrina koji protrče kroz Ajskjub

nikada neće ostaviti trag.

But about ten times a year,

Ipak, oko deset puta tokom godine,

a single high-energy neutrino collides with a molecule of ice,

poneki visokoenergetski neutrino sudari se sa molekulom leda,

shooting off sparks of charged subatomic particles

ispaljujući iskre naelektrisanih subatomskih čestica

that travel faster through the ice than light does.

koje putuju kroz led brže nego svetlo.

In a similar way to how a jet that exceeds the speed of sound

Slično načinu na koji mlaznjak proizvodi zvučni zid

produces a sonic boom,

kada probije brzinu zvuka,

these superluminal charged particles leave behind a cone of blue light,

ove superluminalne naelektrisane čestice ostavljaju za sobom

kind of a photonic boom.

nekakvu fotosku eksploziju.

This light spreads through IceCube,

Ovo svetlo se širi kroz Ajskjub,

hitting some of its detectors located over a mile beneath the surface.

udarajući u neke od njegovih detektora

koji se nalaze na kilometre ispod površine.

Photomultiplier tubes amplify the signal,

Fotomultiplikatorske cevi pojačavaju signal,

which contains information about the charged particles' paths and energies.

koji sadrži informacije o putevima i energiji naelektrisanih čestica.

The data are beamed to astrophysicists around the world

Podaci se usmeravaju ka astrofizičarima širom sveta

who look at the patterns of light

koji pregledaju obrazac svetla

for clues about the neutrinos that produced them.

da bi našli zaključke o neutrinima koji su ih stvorili.

These super energetic collisions are so rare

Ovi superenergetski sudari su toliko retki

that IceCube's scientists give each neutrino nicknames,

da naučnici sa Ajskjuba daju nadimak svakom neutrinu,

like Big Bird and Dr. Strangepork.

kao što su Velika ptica ili dr. Čudnosvinjetić.

IceCube has already observed

Ajskjub je već primetio

the highest energy cosmic neutrinos ever seen.

kosmičke neutrine sa najvišom energijom ikada viđenom.

The neutrinos it detects should finally tell us where cosmic rays come from

Neutrini koje detektuje bi konačno trebalo da nam pruže podatke

o tome odakle dolaze kosmički zraci

and how they reached such extreme energies.

i kako dostižu tako visoke energije.

Light, from infrared, to x-rays, to gamma rays,

Svetlo, od infracrvenog, preko x-zraka do gama zraka,

has given us increasingly energetic

daje nam sve energičnije i konstantno iznenađujuće

and continuously surprising views of the universe.

poglede na svemir.

We are now at the dawn of the age of neutrino astronomy,

Sada se nalazimo na početku doba astronomije neutrina

and we have no idea what revelations IceCube

i ne znamo šta nam otkrića Ajskjuba

and other neutrino telescopes may bring us

i drugih teleskopa za neutrine mogu doneti

about the universe's most violent, most energetic phenomena.

o svemirskim najsnažnijim pojavama sa najvišom energijom.