Fermi's Paradox: And How Intelligent Life Arose On Earth

One day in 1950, in the midst of lunch with colleagues, Italian/American physicist Enrico Fermi suddenly asked, "Where is everybody?"

Fermi wasn't referring to the lunch crowd. What Fermi was pondering was why—with so many Sun-like stars in our Galaxy, and the potential of so many Earth-like planets—our Galaxy wasn't awash with signs of extraterrestrial life.

This apparent contradiction between the high probability of, but total lack of evidence for, extraterrestrial civilizations became kno...