(Submitted March 28, 1997)
It seems that it doesn't make sense to think of the Universe as having
either a center or an edge, but does it then make at all sense to think
of it as having any kind of dimension or size? Perhaps the Universe
contains all sizes and therefore has no sizes. Perhaps I've been reading
too much about Richard Gott and this very bizarre de Sitter space.
You are right that it doesn't make sense to think of the
Universe as having an edge. It is better to think of the
Universe as the surface of a balloon, with the stars and
galaxies on the that surface.
However, we can still think of the Universe as having size and
dimension. Indeed, the Universe does contain all sizes, but
it too has a size, just as the balloon has a size. Physicists
raise questions about the number of dimensions, and have theories
for the Universe consisting of 11 dimensions. This, plus more
familiar concepts such as the curvature of space-time, may make
it difficult to think about the Universe having a size. But
none the less, we consider that it does.
for Imagine the Universe!