A billion years ago (give or take), in a galaxy far, far away, two black holes concluded a cosmic pas de deux. After orbiting each other more and more closely, their mutual gravity tugging each to the other, they finally collided and merged into one. Their collision released enormous energy — equivalent to about three times the mass of our sun. The black holes’ inspiral, collision and merger roiled the surrounding space-time, sending gravitational waves streaming out in every direction at the speed of light. By the time those waves reached earth, early in the morning of Sept. 14, 2015, the once-cosmic roar had attenuated to a barely perceptible whimper. … Continue reading Rainer Weiss, Kip Thorne, Barry Barish