The Time Before Time

It's important to understand that the universe is not expanding into empty space, but space itself is expanding — there was no space before the big bang. It is also important to understand that the universe did not emerge from existing material, but from nothing — there was no matter before the big bang. In fact, chronologically, there was no "before" the big bang because there are no "befores" without time, and there was no time until the big bang. Time, space, and matter came into existence at the big bang. Although the scientific community has generally agreed that the big bang created the universe, it has yet to empirically address what created the big bang.

Norman L. Geisler, Frank Turek