Steady-State Theory

The steady-state theory was inspired at least in part by a 1940s movie entitled Dead of Night. The movie had four parts and a circular structure such that at the end the movie was the same as at the beginning. After seeing this movie in 1946, Thomas Gold, Hermann Bondi, and Fred Hoyle wondered if the universe might not be constructed the same way. The discussion that followed led ultimately to the steady-state theory.

In 1948, Hermann Bondi and Thomas Gold proposed extending the cosmological principle to the perfect cosmological principle, so that the universe looks the same at all times as well as at all locations. They then proposed the steady-state theory based on the new perfect cosmological principle. Because Hubble had already observed that the universe is expanding, Bondi and Gold proposed the continuous creation of matter. Hydrogen atoms created from nothing combine to form galaxies. In this manner the average density of the universe remains the same as the universe expands. In the steady-state, the rate at which new matter is created must exactly balance the rate at which the universe is expanding. Otherwise, the average density of the universe will change and the universe will evolve, violating the perfect cosmological principle. To maintain the steady-state, in a cubic meter of space one hydrogen atom must appear out of nothing every five billion years. In a volume of space the size of the earth the amount of new matter created would amount to roughly a grain of dust in a million years. In the entire observable universe, roughly one new galaxy per year will form from these atoms. Bondi and Gold recognized that a new theory must be developed to explain how the hydrogen atoms formed out of nothing, but did not suggest a new theory.

In the same year, Fred Hoyle proposed a modification of Einstein's general theory of relativity. Hoyle worked independently of Bondi and Gold, but they did discuss the new theories. Hoyle's modification used a mathematical device to allow the creation of matter from nothing in general relativity. No experiments or observations have been made to justify or contradict this modification of general relativity.