Rare Earth Redux: Design Inference, Anyone?

Something else that is special about planet Earth has been noted: its mineral content, compared to other planets. Robert Hazen, an origin-of-life researcher at the Carnegie Institute, states in an article posted by NASA's Astrobiology Magazine that Earth's mineral abundances may be unique in the cosmos. There were only a dozen or so minerals present at the birth of our solar system, he argues, but there are about 5,000 types today. Most of these, he says, can be "linked directly or indirectl...