The dozen or so small rocks in Jeffrey Bada’s lab are nondescript but far from ordinary. They come from a crater near Sudbury, Ontario, that formed 1.85 billion years ago, when a meteorite the size of Mount Everest slammed into Earth. Canadian geologists sent the rocks to Bada, a geochemist at the Scripps Institution of Oceanography, to see if they contained any organic carbon molecules. Not likely, Bada thought: if the molecules hadn’t been incinerated on impact, they would have been destroyed--probably by hungry microbes--long ago. Bada put the rocks on a shelf for a few years.