On Aug. 21, a total solar eclipse will cross the U.S. from Oregon to South Carolina. Ninety-eight years ago today, another total solar eclipse changed the world by helping to confirm Einstein's theory of general relativity.
Imagine a planet like the Earth, orbiting a distant star. Could that planet have life? Well, life on Earth (the only life we know) needs liquid water. So to find life on another planet, we think that that planet would have to be "just right."