Could 1 in 3 Earth-like Worlds Have Life?

Two researchers from Australia believe that life in the Universe may be more common than previously thought. Since life only took half a billion years to gain a foothold on our planet, they theorize, the odds of it happening on any Earth-like world must be good. With only one planet to sample, though, the Earth, there still isn't any way to judge whether our planet is an anomaly or well within the norm. NASA's upcoming Terrestrial Planet Finder due for launch in a decade will help scan for Earth-like planets in the future.