Inflation Theory

CORE DEFINITION

In physical cosmology, cosmic inflation, usually abbreviated to inflation, is a process in which the early universe underwent a phase of accelerated spatial expansion. The inflationary epoch is thought to have begun 10^-36 seconds after the Big Bang and lasted until between 10^-33 and 10^-32 seconds after the Big Bang. Following the inflationary period, the universe continued to expand, but at a much slower rate. The term "inflation" can refer to the hypothesis, the theory, or the epoch itself. The hypothesis and the term "inflation" were first proposed by American physicist Alan Guth in 1980. During the microscopic inflationary period, quantum fluctuations were amplified to cosmic scales, becoming the seeds for the growth of cosmic structure, which explains the formation of the large-scale structure of the universe. Many cosmologists believe that inflation explains several puzzles that previously lacked reasonable answers: why the universe appears the same in all directions (isotropy), why the cosmic microwave background radiation is so uniformly distributed, why the universe is so flat, and why no magnetic monopoles are observed. Although the detailed particle physics mechanism responsible for inflation has not yet been discovered, the basic picture has made several predictions that have been confirmed by observations.