Life in the Universe Is Common, Oldest Fossils on Earth Suggest

In a study published this week in the Proceedings of the National Academy of Sciences, scientists confirmed that the oldest fossils ever discovered — found in a nearly 3.5-billion-year-old rock from western Australia — contain 11 complex microbes that are members of five distinct species.The findings not only suggest that life on our planet originated some 4 billion years ago, but also help support the increasingly widespread theory that life in the universe is much mo