Oct 31, 2012 — NASA's Kepler Mission has been spotting many "Earth-like" planets within our galactic neighborhood. But what fraction of these Earth-like planets are really like our planet? The more we learn about Earth's remarkable properties, the rarer our planet seems to be. And with it, the life it hosts.
Feb 14, 2007 — Ever wonder where the gold in your wedding ring came from? For Valentine's Day, Robert Krulwich tracks the rare element all the way to outer space, where gold is formed in the fiery center of collapsing stars.