Eternal Inflation - History

History

Inflation, or the inflationary universe theory, was developed as a way to overcome the few remaining problems with what was otherwise considered a successful theory of cosmology, the Big Bang model. Although Alexei Starobinsky of the L.D. Landau Institute of Theoretical Physics in Moscow developed the first realistic inflation theory in 1979 he failed to articulate its relevance to modern cosmological problems. Due to political difficulties in the former Soviet Union, regarding the free exchange of scientific knowledge, most scientists outside the USSR remained ignorant about Starobinsky's work until years later. Starobinsky's model was relatively complicated, however, and said little about how the inflation process could start.

In 1979, Alan Guth of the United States developed an inflationary model independently, which did offer a mechanism for inflation to begin: the decay of a so-called false vacuum into "bubbles" of "true vacuum" that expanded at the speed of light. Guth coined the term "inflation", and he was the first to discuss the theory with other scientists worldwide. But this formulation was problematic, as there was no consistent way to bring an end to the inflationary epoch and end up with the isotropic, homogeneous Universe observed today. (See False vacuum#Development of theories). In 1982, this "graceful exit problem" was solved by Andreas Albrecht and Paul J. Steinhardt and also independently by Andrei Linde.

In 1986, Linde published an alternative model of inflation that also reproduced the same successes of new inflation entitled "Eternally Existing Self-Reproducing Chaotic Inflationary Universe", which provides a detailed description of what has become known as the Chaotic Inflation theory or eternal inflation. The Chaotic Inflation theory is in some ways similar to Fred Hoyle’s steady state theory, as it employs the metaphor of a universe that is eternally existing, and thus does not require a unique beginning or an ultimate end of the cosmos.