THE latest attempt to work out how much alien life is out there suggests there may be a lot more than most people thought.
According to a new statistical analysis based on how quickly life got going on Earth, life will start on at least a third of Earth-like planets within a billion years of them developing suitable conditions. And with recent discoveries that planets are common around Sun-like stars, there’s probably no shortage of prospective homes.
Earlier attempts to estimate the likelihood of life on Earth-like planets floundered because we have only a single data point—the Earth itself. Isotopic…
