In 1916, Einstein made a bold prediction-- that gravity actually travels in waves. These “gravitational waves” would be ripples in the fabric of space a bit like ripples on a pond, and would slightly stretch and squash the distances between things as they passed. "Einstein himself who came up with the theory didn't think that would ever really be detected," says Leslie Wade , assistant professor of Physics at Kenyon College in Gambier, Ohio. Anything with mass can make gravitational waves by