What is the universe made of? - Dennis Wildfogel

Iz čega se sastoji svemir? - Denis Vajldfogel (Dennis Wildfogel)

Prevodilac: Anca Dimovska Lektor: Mile Živković

All the material objects around you

Svi opipljivi objekti oko vas

are composed of submicroscopic units

su sastavljeni od submikroskopskih jedinica

we call molecules.

koje zovemo molekuli.

And molecules in turn are composed

A molekuli su sastavljeni

of individual atoms.

od zasebnih atoma.

Molecules frequently break apart

Molekuli se često razlažu

and then form new molecules.

i onda grade nove molekule.

On the other hand,

Sa druge strane,

virtually all the atoms you come in to contact with

praktično svi atomi sa kojima stupite u kontakt

through the course of your life,

tokom života,

the ones in the ground beneath you,

oni na tlu ispod vas,

the air you breath, the food you eat,

u vazduhu koji dišete, u hrani koju jedete,

those that make up every living thing, including you,

oni koji čine svaku živu stvar, uključujući i vas,

have existed for billions of years

postoje milijardama godina

and were created in places very unlike our planet.

i stvoreni su na mestima koja nisu uopšte kao naša planeta.

How those atoms came about is what I want to share with you.

Kako su ti atomi nastali je ono što želim da podelim sa vama.

It all started 14 billion years ago

Sve je počelo pre 14 milijardi godina

with an event we call The Big Bang,

pojavom koju zovemo Veliki prasak,

which resulted in a universe consisting of gas alone.

čiji je ishod bio da se svemir sastojao samo od gasa.

There were no stars and no planets.

Nije bilo zvezda ni planeta.

The gas was made up only of atoms

Gas se samo sastojao od atoma

belonging to the simplest elements.

koji su pripadali najjednostavnijim elementima.

It was about 75 percent hydrogen

To je bilo 75% vodonika

and almost all the rest was helium.

a skoro sve ostalo je bio helijum.

No elements like carbon, oxygen or nitrogen existed.

Nisu postojali elementi kao što je ugljenik, kiseonik ili azot.

No iron, silver or gold.

Ni gvožđe, srebro ili zlato.

In some places, the density of this gas was slightly higher than in others.

U nekim mestima, gustina gasa je bila malo viša.

Due to gravity, those places attracted even more gas,

Zbog gravitacije, ta mesta su privlačila još više gasa,

which further strengthened the pull of gravity,

koji je dalje jačao gravitaciju,

which then drew more gas in, and so on.

koja je povlačila više gasa, i tako dalje.

Eventually, large dense gas balls formed,

Na kraju, stvorene su lopte gustog gasa,

shrinking under their own gravity

skupljajući se pod sopstvenom gravitacijom

and consequently heating up on the inside.

i tako su se grejale iznutra.

At some point, the core of such a ball

U nekom trenutku, jezgro takve lopte

gets hot enough that nuclear fusion occurs.

postaje toliko vrelo da se dešava nuklearna fuzija.

Hydrogen atoms smash together to form helium,

Atomi vodonika se sudaraju i stvaraju helijum,

accompanied by a great release of energy,

što prati veliko oslobađanje energije,

strong enough to counteract the shrinking force of the gravity.

dovoljno jako da se usprotivi skupljajućoj sili gravitacije.

When the energy pushing out from the fusion reactions

Kada je energija koja se oslobađa nuklearnim fuzijama

matches the gravity pulling all the gas inwards,

jednaka gravitaciji koja vuče gas unutra,

an equilibrium occurs.

dešava se ravnoteža.

From this a star is born.

Iz ovoga je rođena zvezda.

Over its lifetime,

Tokom njenog života,

the fusion reactions in the core of a massive star

fuzije u jezgru ogromne zvezde

will produce not only helium,

proizvešće ne samo helijum,

but also carbon, oxygen, nitrogen

već i ugljenik, kiseonik, azot

and all the other elements in the periodic table up to iron.

i sve druge elemente periodnog sistema do gvožđa.

But eventually, the core's fuel runs out,

I na kraju, fuziono jezgro se istroši

leaving it to collapse completely.

i dovodi do potpunog prestanka.

That causes an unbelievably powerful explosion

Ovo izazviva neverovatno moćnu eksploziju.

we call a supernova.

koju zovemo supernova.

Now there are two things to note

Primetimo dve stvari

about how supernovas create elements.

o tome kako supernove stvaraju elemente.

First, this explosion releases so much energy

Prvo, ova eksplozija oslobađa toliko energije

that fusion goes wild

da fuzija podivlja

forming elements with atoms even heavier than iron

stvarajući elemente sa atomima čak težim od gvožđa,

like silver, gold and uranium.

kao što je srebro, zlato i uranijum.

Second, all the elements that had been accumulating

Drugo, svi elementi koji su se sakupljali

in the core of the star,

u zvezdinom jezgru,

like carbon, oxygen, nitrogen, iron,

kao što je ugljenik, kiseonik, azot, gvožđe,

as well as all of those formed in the supernova explosion,

kao i oni stvoreni u eksploziji supernove,

are ejected in to interstellar space

su izbačeni u međuzvezdani prostor

where they mix with the gas that's already there.

gde se mešaju sa gasom koji tu već postoji.

History then repeats itself.

Ovde se istorija ponavlja.

Gas clouds, now containing many elements

Oblaci gasa, koji sad sadrže mnoge elemente

besides the original hydrogen and helium,

pored pređašnjih vodonika i helijuma,

have higher density areas

imaju oblasti veće gustine

that attract more matter, and so on.

koji privlače više materije, i tako dalje.

As before, new stars result.

Kao i pre, nastaje nova zvezda.

Our sun was born this way about 5 billion years ago.

Naše Sunce je rođeno na ovaj način pre oko 5 milijardi godina.

That means that the gas it arose from

Ovo znači da je gas od kojih je stvoreno

had itself been enriched with many elements

bio obogaćen mnogim elementima

from supernova explosions since the universe began.

iz eksplozija supernove od početka svemira.

So that's how the sun wound up with all the elements.

Tako je Sunce završilo sa toliko elemenata.

It's still mostly hydrogen at 71 percent,

I dalje je uglavnom vodonik, 71%,

with most of the rest being helium at 27 percent.

a većina ostatka je helijum, 27%.

But bear in mind

Ali imajte na umu

that while the first stars were made up

da dok su prve zvezde sadržale

of hydrogen and helium alone,

samo vodonik i helijum,

the remaining elements in the periodic table

ostali elementi periodnog sistema

make up two percent of the sun.

čine dva procenta Sunca.

And what about Earth?

A šta je sa Zemljom?

Planets form as an incidental process to star formation

Planete nastaju kao slučajni proces pri stvaranju zvezda

out of the same gas cloud as the star itself.

iz istog oblaka gasa kao i same zvezde.

Small planets like ours don't have enough gravity

Male planete kao naša nemaju dovoljnu gravitaciju

to hold on to much hydrogen or helium gas

da zadrže mnogo gasa vodonika i helijuma

since both of those are very light.

jer su oba veoma laka.

So, even though carbon, nitrogen, oxygen and so on

Iako ugljenik, azot, kiseonik i drugi

made up only two percent of the gas cloud from which Earth was formed,

čine samo dva procenta oblaka gasa iz kojeg je nastala Zemlja,

these heavier elements form the bulk of our planet

ovi teži elementi grade masu naše planete

and everything on it.

i sve na njoj.

Think about this:

Pomislite na ovo:

with the exception of hydrogen and some helium,

sa izuzetkom vodonika i nešto helijuma,

the ground you walk on,

zemlja po kojoj hodate,

the air you breath, you,

vazduh koji dišete, vi,

everything is made of atoms

sve je sastavljeno od atoma

that were created inside stars.

koji su stvoreni unutar zvezda.

When scientists first worked this out

Kada su naučnici ovo najpre shvatili

over the first half of the 20th Century,

tokom prve polovine 20. veka

the famous astronomer Harlow Shapley commented,

poznati astronom Harlou Šepli je izjavio:

"We are brothers of the boulders, cousins of the clouds."

"Mi smo braća stenama, rođaci oblaka".