Transcript: In 1981, MIT physicist Alan Guth was looking for possible explanations for the smoothness and flatness of the universe when he came up with the idea of cosmic inflation. Inflationary cosmology is an adjustment to the standard big bang model wherein the universe went through a period of extremely rapid or exponential expansion at a time ten to the minus thirty-five to ten to the minus thirty-three seconds after the big bang; that’s a billion-billion-billion-billionth of a second after the big bang. In this tiny iota of time the universe expanded by forty orders of magnitude from smaller than an atomic nucleus to the size of about a grapefruit. The cause of inflation was the energy derived from a phase transition, such as that occurs when ice turns into water, which is associated with the unification of three of the fundamental forces of nature: the weak nuclear force, the strong nuclear force, and the electromagnetic force.