Dave Spiegel (IAS)

How Probable is Life? Climatic Habitability and Abiogenesis

The explosion of exoplanet discoveries in recent years brings us ever closer to the goal of finding a planetary twin to Earth. But what features of a planet affect whether it is hospitable to life? I will discuss various properties of a planet that can influence its climatic habitability, including the important role played by the detailed architecture of the planetary system in which it resides. I will then examine how the early emergence of life on Earth affects our estimate of the probability of life arising, given early-Earth-like conditions. Although paleobiological evidence for early life on Earth provides some justification for optimism about the prevalence of life in the universe, the evidence is not dispositive, and life might nevertheless be rare.