I, along with many other people, believe (for the most part) in the big bang. However matter cannot be created or destroyed, so where did it come from to allow the big bang to happen in the first place? I also believe that there are countless other universes much like our own. I was wondering if its possible that perhaps one of these universes has different laws of matter than our own and that matter can be created and or destroyed. From this i hatched 2 main possibilities: either this universe has so much energy in it that it can actually create new universes or there are already empty universes and they somehow temporarily connect with the other one allowing energy/matter to fill it. Could someone please point out all the flaws in this personal theory of mine, and also give a couple of widely accepted theories that are more plausible?