Re: "...a large number of alternative universes."
You're confusing one sort of multiverse (Everett's Many World's theory of quantum mechanics) with the cosmological version, but don't feel bad, they're all equal in the 'load of unproven old bollox' stakes.
Max Tegmark classified the various sorts of multiverse a while ago :
http://space.mit.edu/home/tegmark/crazy.html
I must admit, I do like the page url...