In the fall of 1919, Albert Einstein received an urgent telegram informing him that astronomers had observed evidence of the bending of light by the sun’s gravity, validating a key prediction of his general theory of relativity. He handed the cable to a student, who began congratulating him. “But I knew that the theory is correct,” he interrupted. And what, she asked, if the observations had disagreed with his calculations? “Then I would have been sorry for the dear Lord,” Einstein answered. “The theory is correct.”