There may be many Big Bangs that happened at various and far-flung locations, each creating its own swelling, spatial expanse, each creating a universe - our universe being the result of only one of those Big Bangs.

How can a speck of a universe be physically identical to the great expanse we view in the heavens above?

Our eyes only see the big dimensions, but beyond those there are others that escape detection because they are so small.

String theory envisions a multiverse in which our universe is one slice of bread in a big cosmic loaf. The other slices would be displaced from ours in some extra dimension of space.

...things are the way they are in our universe because if they weren't, we wouldn't be here to notice.

String theory has the potential to show that all of the wondrous happenings in the universe - from the frantic dance of subatomic quarks to the stately waltz of orbiting binary stars; from the primordial fireball of the big bang to the majestic swirl of heavenly galaxies - are reflections of one, grand physical principle, one master equation.