In 2005 the Sloan Digital Sky Survey burst onto the scene--an amazingly detailed new map of the universe created by a small group of visionary scientists, led by the beloved and multi-talented astronomer James Gunn--just awarded the National Medal of Science. Suddenly cosmologists were flooded with so many powerful new discoveries that, as one said, it was like drinking out of a fire hose. At last they could trace the universe's whole history and peer into vast swaths of never before charted deep space. The Sloan survey was put on the web for free, and it has launched a brave new era of...