The oscillatory universe is a cosmological model originally derived by Alexander Friedman in 1922. It was investigated briefly by Einstein in 1930 and Richard Tolman in 1934.
It is a theory in which the universe undergoes a series of oscillations (bounces), each beginning with a big bang and ending with a big crunch. After the big bang, the universe expands for a while before the gravitational attraction of matter causes it to collapse back in and undergo a bounce.
In the 1960s, Stephen Hawking, Roger Penrose and George Ellis showed that singularities were a universal feature of cosmologies with a big bang and that no feature of general relativity could prevent them. There was little reason to postulate cycles before or after the present one. Other measurements suggested the universe is not closed. These arguments caused most cosmologists to abandon the oscillating universe model.
John Archibald Wheeler, who believed that a closed universe was necessary on general principles, speculated that the fundamental physical constants could be re-processed to new values at each bounce, providing a mechanism for anthropic selection.
The theory was revived in brane cosmology as the cyclic model (which evades most of the arguments leveled against the oscillatory universe in the sixties). However the theory is still controversial, largely because there is no satisfactory string theoretic description of the bounce in this model.
· 1 decade ago