Parallel Universe Theories
The Theory of Parallel Universes
The multiverse is a theory in which our universe is not the only one, but states that many universes exist parallel to each other. These distinct universes within the multiverse theory are called parallel universes. A variety of different theories lend themselves to a multiverse viewpoint. Not all physicists really believe that these universes exist. Even fewer believe that it would ever be possible to contact these parallel universes.
Level One Universe
These exist in our own space-time and are simply an extension of our own infinite universe. This is based on the "Inflationary Theory", which states the Universe is constantly expanding on an infinite scale. Mathematical odds dictate that since the Universe is infinite in size then there MUST be infinite versions or copies of everything from particles, to planets, to stars. So yes that means infinite versions of Earth ,you, and me. Obviously in each version our lives will be slightly or drastically different(if we are still alive at all).The only thing separating us from 'them ' is great distances, distances so far light from the closest one hasn 't reached us yet, and won 't for an insane amount of time. For the Universe to be infinite it has to be flat and recent test show it is, although it could be curved just so ever slightly our test can not determine the curve(I think the Universe is curved and spherical).An example of just how far the closest "spatial parallel Earth may be is at least Googleplex yards away, that is 1 with 200 zeros!
Level Two Universe
In a level two universe our universe is simply one of a "Multi-verse", one of many "soap bubble shaped universes of infinite size". These float around in an exo-universal medium referred to by physicist as "Hyperspace" or "The Bulk". Within this Hyperspace bubbles(universes) interact ,are created, destroyed, and spawn others out of themselves. Now
Cited: http://science.howstuffworks.com/parallel-universe.htm http://www.dailygalaxy.com/my_weblog/2009/05/parallel-univer.html http://space.mit.edu/home/tegmark/crazy.html http://palscience.com/space/multiverse-and-parallel-universes-theory-by-dr-michio-kaku/