The Really Big Bang

by Dr. Richard Muller
Professor of Physics
University of California, Berkeley

Narrative Index

There are more galaxies in the universe than stars in the Milky Way and there are an estimated 10 billion stars in the Milky Way. What Hubble observed is that all these galaxies are moving away from us and that the ones that are further away are moving away faster. We seem, from our vantage point on Earth, to be the center of the universe; however, from any perspective in the universe, galaxies appear to be moving away. Really, there is no center to the universe.

The universe began in an explosion we call the Big Bang. This was not an explosion of matter into a previously empty space, but an explosion of space itself. When did the Big Bang occur? By using the velocity at which galaxies are moving it is possible to calculate the time when everything was on top of everything which is estimated to be 10 to 20 billion years ago. This early universe was extremely dense and hot according to Gamov.

An important confirmation of the Big Bang is the discovery by Penzias and Wilson of microwave radiation--a 4000 megahertz signal coming from distant space associated with what appears to be a black body spectrum. By measuring the uniformity of this radiation, we can ascertain whether or not the Earth is moving. Penzias and Wilson measured a red shift to this radiation confirming the Big Bang.

Determining the dominant matter of the universe is the key to understanding it. This is one of the outstanding issues of science. Probably 10 to 20 percent of matter is made out of protons, neutrons, and electrons; the rest we don't know.

Another issue: Matter is slowing down. Will it eventually fall back in? The current research suggests that the universe will expand forever.