So , we don't know how universe began?

Question

Do we?
In one of my previous Q's : http://answers.yahoo.com/question/index;_ylt=Akghk9jTxh6r__0mfvTQ2BHty6IX;_ylv=3?qid=20070615215602AARrm8m
(look at the best answer)

How did we get "mass of dust, gas, and debris" and "deutrium"
Is there an explanation or we just dont know???

Answer 1

right now we think we know how the universe began. most of the science community is in agreement about the big bang.

the big bang theory says that the universe started with a massive explosion of this tiny ball of pure energy, no matter, just energy. that explosion is said to have created space and time. so there was no before the big bang because prior to it there was no time. and there was nothing except that small ball of energy because there was no space.

eventually some of that energy cooled down to about a billion degrees and formed matter (remember, einstein said matter and nergy are the same). it formed a few different types of elementary particles, but for this well just talk about quarks and leptons.

so now there is massive amount of quarks and leptons floating around at high speeds. 2 "up" quarks and 1 "down" quark (the names are just so its easy to remember) form a proton, or the very first hydrogen ions, and 2 down and 1 up form a neutron. when temperatures cool down enough electrons (which are leptons) cool down and attach themselves to the hydrogen ions and form normal hydrogen atoms.

that process happened countless times in the early universe until enough hydrogen was there to form that mass of dust and debris you mentioned, which later formed stars.

now as for deuterium. its just an isotope of hydrogen. it has 1 proton and 1 neutron with 1 orbiting electron. the only known source for how deuterium could've been created is during the big bang in the process i just described. its one of the big arguments for why the big bang theory is true.

EDIT: i left out the most important part. when it comes down to that small ball of energy, we dont know where that came from. some theories, like m-theory and string thoery, try to explain it. i wont go into that here, your best off looking into it on google or wikipedia.