Why does everyone assume the "Big Bang" was a singular event? It's my guess that the Big Bang is ongoing with matter constantly pouring in from the other membrane or whatever source of matter and energy you choose to accept. Given our space-time "volume" is porportional to the density of matter in it, it continues to expand. If the rate of expansion of the universe is accelerating, so is the rate that matter is pouring into it from the epi-center where the "big bang" occurred.
Merged post follows:
Consecutive posts mergedOh yeah, I should probably mention my other theory that black holes are not atom sized objects of unimaginable density but rather a porthole from our familiar 4D space time dimension into another dimension predicted by String theory. Imagine a point in our universe where space-time is pulled through a knot-hole and is turned inside out. The sack that forms fills up with the matter that is pulled into it beyond the event horizon and expands into the other dimension. Density differences between the various dimensions may determine the rate of accretion. Because this dimension occupies the same space that we do, it can't be seen, only "felt". The one thing I'm not sure about is "does the matter in the new dimension fill the other dimension(s) in the immediate area of the black hole or are there other laws of physics that permit the matter to scatter throughout the universe to maintain equilibrium?".