Ultimate fate of the universe out a theory that has since come to be called the Big Bang theory of the origin of the universe. In 1948, Fred Hoyle set out his opposing Steady State theory in which the universe continually expanded but remained statistically unchanged as new matter is constantly created. These two theories were active contenders until the 1965 discovery, by Arno Penzias and Robert Wilson, of the cosmic microwave background radiation, a fact that is a straightforward prediction of the Big Bang theory, and one that the original Steady State theory could not account for. As a result, the Big Bang theory
Big Bang of the origin and evolution of the universe. Much of the current work in cosmology includes understanding how galaxies form in the context of the Big Bang, understanding the physics of the universe at earlier and earlier times, and reconciling observations with the basic theory. In 1968 and 1970 Roger Penrose, Stephen Hawking, and George F. R. Ellis published papers where they showed that mathematical singularities were an inevitable initial condition of general relativistic models of the Big Bang. Then, from the 1970s to the 1990s, cosmologists worked on characterizing the features of the Big Bang universe and resolving outstanding