"It may be that planets spent a long time in a microbial life condition and then only rarely evolved to advanced multicellular complex life," Johnson said. "That's one of the hypothesis we would test."
"There's a story always hidden in rocks," said geoscientist Clark Johnson, the lead investigator for the Wisconsin Astrobiology Research Consortium. "... It's up to (geologists) to be clever enough to find the tools that we need to interrogate those rocks to find what story they preserve."