According to the Inflation Theory our Observable Universe is but a small part of the total universe created in the Big Bang. Our observable universe appears to be flat (just like Earth at sea level may appear flat), while the total universe may be shaped like a balloon. If we assume our observable universe was at one specific area in the pre-inflation universe, and other areas are now other universes no longer in causal contact with our universe, what lies between the universes? Is there a uniform distribution of mass in the total universe, with each universe just being defined by how far one can observe in any direction? So our observable universe is slightly different from the observable universe of any sentient beings in the Andromeda galaxy? Or is the observable universes like a galaxies or galaxy clusters, with vast expanses of empty space between them?