A Lazarus bacterium which thrived millions of years before dinosaurs walked the Earth has been brought back to life. Biologists are astonished that the 250-million-year-old bug could be revived. It suggests that if conditions are right, bacterial spores might survive indefinitely. John Parkes, a geomicrobiologist at the University of Bristol, comments: “All the laws of chemistry tell you that the complex molecules in the spores should have degraded to very simple compounds such as carbon dioxide.” He wonders that if it is proven that spores can survive this long, why should they die at all? “Where else are these dormant organisms waiting to be reawakened?”