The other possible model permitted by the mathematical solution of Einstein’s equation, according to Friedmann is the ‘hyperbolic universe’. This model suggests that from an infinitely thin state an eternity ago, the universe contracted until it reached the maximum density, from which it rebounded to an unlimited expansion which will go on indefinitely in the future.[1] It means that the universe is beginning less and endless. Dr. Gamow’s theory of evolutionary universe, in fact, is based on the model of hyperbolic universe, and thus the ultimate beginning and end of the universe are pushed back to infinity. In the words of Dr. George Gamow, “Thus we conclude that our universe has existed for an eternity of time, that until about five billion years ago, it was collapsing uniformly from a state of infinite rarefaction; that five billion years ago it arrived at a state of maximum compression in which the density of all its matter may have been as great as that of the particles packed in the nucleus of an atom, and that the universe is now on the rebound, dispersing irreversibly towards a state of infinite rarefaction.”[2]
Out of the two possible models of the universe suggested by Friedmann, which one represents the actual universe has not yet been definitely decided, for there are evidences on both the sides.[3]