The relativity of simultaneity is one of the most important and profound concepts of physics, and a revolutionary insight into the nature of time. The notion of an absolute cosmic time, with absolute simultaneity between distant events, was swept out of physics by Einstein’s equations dealing with the nature of space and time. In fact, it makes little sense to ask questions like “What happened on a distant star at the precise moment President Kennedy was killed?”

Clifford A. Pickover, Time: A Traveler’s Guide (11)