Neo dai, big bang is not a belief.
Lemme mention something. Every matter is made up of atoms.
You and me are atoms at minuscule level. Do you know why
atoms in us are together giving us mass whereas there are atoms
all over with no mass? Scientists haven given
it a name called 'Higgs Boson' that is giving atoms a mass. They
also call it 'God Particle'. They tried to find it during experiment done
on Large Hadron Collider in Switzerland. Experiment was semi-success.
Universe as we see is indeed an end result of massive atomic collision
that we like to call it as big bang. All this expansion of universe is somewhat
similar to ripples when you drop a pebble in a pond. But the fact is it also
is going to contract, if so universe we know today may not exist. For now we're
seeing universe in as ever expanding state. No doubt about it.
Among other things, there are so many things Science can not answer and
it was the question—what was there before big bang?
So far whatever science has discovered, it's proven and based on facts. I may
not really count on their estimate with full confidence but they're always right on it.
If earth didn't exist 14 billion years ago, I may not believe their estimate of exact
14 billion years but I may believe their findings that at some point earth certainly
wasn't there.

Someone posting here verses from man-made books, now I call it belief and faith.
Before Galileo, everyone believed earth was flat. Religious faith is somewhat like
that notion 'earth was flat' — a faith, a belief.