Where did Earth’s water come from? - Zachary Metz

Odakle potiče voda na Zemlji? - Zekari Mec (Zachary Metz)

Prevodilac: Mile Živković Lektor: Anja Saric

It has no taste, color or smell, and we often look right through it.

Nema ukus, boju i miris i često možemo da vidimo kroz nju.

It covers over 70% of the Earth,

Prekriva 70% Zemlje

cycling from the oceans and rivers to the clouds and back again.

i cirkuliše od okeana i reka do oblaka i nazad.

It even makes up about 60% of our bodies.

Ona čak čini oko 60% naših tela.

With all this water around and inside us,

Sa svom tom vodom oko nas i u nama,

it's easy to take its presence for granted.

lako je uzeti njeno prisustvo zdravo za gotovo.

But in the rest of the solar system, liquid water is almost impossible to find.

Ali u ostatku sunčevog sistema, tečnu vodu je skoro nemoguće naći.

So how did our planet end up with so much of this substance

Kako je onda naša planeta završila sa toliko ove supstance

and where did it come from?

i odakle je ona potekla?

As you probably know,

Kao što verovatno znate,

a water molecule consists of two basic parts.

molekul vode sastoji se od dva osnovna dela.

Hydrogen, the simplest of all elements,

Vodonik, najjednostavniji element,

has been around since close to the beginning of our universe.

postoji skoro od samog početka univerzuma.

Oxygen entered the scene several hundred million years later

Kiseonik je nastao nekoliko stotina miliona godina kasnije

after stars began to form.

nakon što su počele da se formiraju zvezde.

The massive pressure at the center of these fiery infernos was so great

Ogromni pritisak u sredini ovih vatrenih ognjeva bio je tako velik

that hydrogen atoms fused together to form helium.

da su se atomi vodonika stopili i obrazovali helijum.

Helium, in turn, fused to form heavier elements,

Helijum se zauzvrat stopio kako bi nastali teži elementi,

like beryllium, carbon and oxygen in a process known as nucleosynthesis.

poput berilijuma, ugljenika i kiseonika u procesu poznatom kao nukleosinteza.

When stars eventually collapsed and exploded into supernovas,

Kada su se zveze u jednom trenutku sudarile i eksplodirale u supernove,

these new elements were spread across the universe

ovi novi elementi raširili su se univerzumom

and combined into new compounds, like the now familiar H2O.

i kombinovali u nova jedinjenja, poput sada poznatog H2O.

These water molecules were present in the dusty cloud

Ovi molekuli vode bili su prisutni u oblaku prašine

that formed our solar system

koji je oblikovao naš sunčev sistem

and more collided with our planet after its formation.

i još njih se sudarilo sa našom planetom nakon njenog nastanka.

But there's a big question that we don't have the answer to:

Ali na jedno veliko pitanje nemamo odgovor:

how much water arrived on Earth, and when?

koliko vode je došlo na Zemlju, i kada?

If, as one theory goes,

Kako jedna teorija kaže, ako su

relatively small amounts of water were present on Earth when the rock formed,

relativno male količine vode bile prisutne na Zemlji kada je nastala stena,

the high temperatures and lack of any surrounding atmosphere

visoke temperature i nedostatak atmosfere

would have caused it to evaporate back into space.

bi prouzrokovao da voda ispari nazad u svemir.

Water would have been unable to remain on the planet

Voda ne bi mogla da ostane na planeti

until hundreds of millions of years later

do stotina miliona godina kasnije

when our first atmosphere formed through a process called outgassing.

kada je nastala naša prva atmosfera u procesu koji se naziva degazacija.

This occurred when molten rock in the Earth's core

Ovo se desilo kada su istopljene stene u Zemljinom središtu

released volcanic gasses to the surface,

ispustile vulkanske gasove na površinu,

creating a layer that could then trap escaping water.

stvarajući sloj koji bi onda mogao da zarobi vodu koja izlazi.

So how then did water get back to the planet?

Kako se onda voda vratila na planetu?

Scientists have long suspected

Naučnici su dugo sumnjali na to

that much of it was brought by ice-bearing comets,

da je dosta vode vraćeno putem kometa koje su nosile led

or more likely asteroids that bombarded the Earth over millions of years.

ili verovatnije asteroidima koji su bombardovali Zemlju milionima godina.

Recent research has challenged this theory.

Skorašnja istraživanja izazvala su ovu teoriju.

In examining carbonaceous chondrite meterorites

Ispitivanjem meteorita ugljeničnog hondrita

that formed shorty after the birth of our solar system,

koji su nastali ubrzo nakon formiranja našeg sunčevog sistema,

scientists have found that not only did they contain water,

naučnici su otkrili da oni ne samo da su imali vodu,

but their mineral chemical composition matched rocks on Earth

već su imali i isti mineralni sastav kao i stene na Zemlji

and samples from an asteroid that formed at the same time as our planet.

i uzorci sa asteroida koji je nastao u isto vreme kad i naša planeta.

This suggests that the Earth may have accumulated

Ovo naznačava da je Zemlja možda ranije nagomilala

a substantial amount of water early on that was able to stay put,

značajne količine vode koja je mogla da miruje,

despite the lack of an atmosphere,

uprkos nedostatku atmosfere,

though asteroids may have brought more over the eons.

iako su asteroidi možda doneli još vode tokom eona.

If this turns out to be true,

Ukoliko je ovo istina,

life may have formed much earlier than previously thought.

život je možda nastao ranije nego što se pre mislilo.

So we do not yet definitively know whether the water on Earth

Tako da još uvek ne znamo tačno da li je voda na Zemlji

came from its initial formation,

potekla iz njene prvobitne formacije,

later impacts,

iz kasnijih uticaja

or some combination of the two.

ili neke kombinacije ova dva.

Regardless, the water that runs from our showers, drinking fountains and faucets

Bez obzira, voda koja teče našim tuševima, fontanama za piće i česmama

is something that didn't just come from a nearby lake or river,

je nešto što nije samo poteklo iz obližnjeg jezera ili reke,

but first underwent a cosmic and chaotic journey to get here.

već je prvo prošla kosmičko, haotično putovanje, da bi dotle došla.