You are asking me something that no one knows the answer to, RET or FET. Rather than guess at big bangs or God or a universe that has always been or any other round earth wild stab in the dark, I am comfortable to say I don't know. No one does. Our science is based on Zetetic observation. Now being as I was not around at the conception of the universe, it is very difficult for me to say exactly what happened. And there is not enough hard evidence to suggest a firm answer. It is like me asking you ... What caused the big bang? How can everything come from nothing? Provide evidence that something can arise from nothing. Its a line of questioning I a happy to reply to, with an "I don't know". - And neither do you.