Wei Dai, <weidai@eskimo.com>, writes:
> I don't understand this either. How can there be a infinity of points at
> one Planck time after the Big Bang at the center of mass of the universe?
I don't think the universe has a center of mass in most models. The homogeneity of the universe is a fundamental assumption. A homogeneous universe may be spatially closed, like the surface of a hypersphere, and have a finite size. Or it may be spatially open, like a plane, and have an infinite size. But in neither case is there a center of mass.
Hal