The Big Bang Theory

As early as 1921, the Russian astronomer Alexander Friedman had calculated precisely how the expansion rate would gradually slow. Hubble's observations weren't extensive or accurate enough to detect any change in the rate of expansion over the few million years that they encompassed. The breaking effect of gravity was easy enough to study theoretically. But such was the tentative nature of these early results that no leading scientist was prepared to take the plunge and state the obvious implication.