You don't need to know any of that to be an Atheist. In fact you can know and believe absolutely nothing and you will by definition be an Atheist.
No-one yet knows what happened at or "before" the big bang. The starting point for any investigation is "I don't know", not "Goddidit unless you can prove otherwise".
No-one yet knows what happened at or "before" the big bang. The starting point for any investigation is "I don't know", not "Goddidit unless you can prove otherwise".