This evidence is strictly that we now observe the universe to be expanding so that the separations between galaxies are increasing. If we run this process back in time, we arrive at a state of the universe when the universe was very dense and hot. General relativity provides a framework for making precise calculations of what our 'expanding' universe was doing in the past, and these solutions all require an origin of time a finite number of years ago. There doesn't seem to be any way out of this implication, without doing great violence to other verified predictions which follow from general relativistic Big Bang cosmology. Several proposed quantum mechanical extensions to general relativistic gravity suggest that there was, in fact, no 'time zero' because such an instant would have gotten 'smeared out' in a quantum mechanical haze of possibilities. Instead of time having a beginning, it just fritters away into some odd kind of quantum mechanical process.

Copyright 1997 Dr. Sten Odenwald