Steady-State Theory

Was there a moment of creation for the universe, or has the universe always existed? The steady-state theory is a cosmological theory for the origin of the universe that suggests the universe has always existed and did not have a moment of creation. This theory was popular during the 1950s and 1960s, but because of observations made during the 1960s, few, if any, astronomers now think that the steady-state theory is correct. The basic tenet of the steady-state theory is that the universe on a large scale does not change with time (evolve). It has always existed and will always continue to exist looking much as it does now. The universe is, however, known to be expanding. To allow for this expansion in an unchanging universe, the authors of the steady-state theory postulated that hydrogen atoms appeared out of empty space. These newly created hydrogen atoms were just enough to fill in the gaps caused by the expansion. Because hydrogen is continuously being created, the steady-state theory is sometimes called the continuous creation theory. This theory achieved great popularity for a couple of decades, but mounting observational evidence caused its demise in the late 1960s. The discovery in 1965 of the cosmic background radiation provided one of the most serious blows to the steady-state theory.

There are a number of observations that astronomers have made to test cosmological theories, including both the steady-state and the big bang theory. Some of these cosmological observations are described below.