Your statement would be correct in that case, but I was taught that it [b]was[/b] the beginning of the universe. So, if it was the beginning (and I'm not saying it was) it wouldn't be possible without any pre-existing energy. Which would bring up the question of how that energy came to be. That question is where a lot of people believe that God came in. I personally can't find any actual good explanation for how there could be pre-existing energy, in that situation.