Weiss P. Light pulses flout sacrosanct speed limit. — Science News 157 (24): 375. June 10, 2000, doi:10.2307/4012354
Five years ago, a wave of discontent swept away the 55-mile-per-hour U.S. speed limit. Nowadays, some physicists are taking a hard look at the 670-million-miles-per-hour speed limit of light in a vacuum, or c.
Albert Einstein posted this limit in his 1905 theory of special relativity. Although popular lore and some physics textbooks still contend that nothing races faster than c, experiments going back decades have repeatedly shown that light can beat that speed under certain conditions.