Before the discovery of the cosmic microwave background, it seemed possible
that we might be living in a "steady-state universe" with overall properties
that do not change with time. The steady-state model, like the Big Bang model,
assumes an expanding universe, but does not assume a "creation event."
Instead, matter is assumed to be created continuously everywhere in space to
ensure that the average density of the universe remains constant. Search the
World Wide Web for information about the steady-state theory. Explain why the
existence of the cosmic microwave background was a fatal blow to the steady-
state theory.