The Rare Earth Hypothesis: Why Habitable Planets May Be Extremely Rare in the Universe

Our universe is billions of years old and contains trillions of worlds, plenty of time and space for extraterrestrial civilizations to emerge, spread, and contact us. Yet we see no evidence of intelligent life on other planets. Where is everyone? One explanation is the Rare Earth Hypothesis. Highly habitable worlds, capable of supporting the evolution of intelligent tool users who can make rockets and space telescopes may be far rarer than we've assumed— one in a million, one in a billion- or maybe even rarer than that by orders of magnitude. If you haven't already, you may want to check out my first video on this problem, which sets up the Fermi Pardox- the absence of evidence for intelligence in a universe that seems to provide plenty of room for it- and discusses it in terms of the evolutionary biology.