IN ITS toughest test yet, Einstein’s theory of special relativity has passed with flying colours.
Holger Müller of the University of Konstanz in Germany and his colleagues have carried out a modern-day version of the 19th-century Michelson-Morley experiment, which revealed that the speed of light is the same in every direction—a vital foundation for special relativity. They did this using state-of-the-art optical cavities chilled to near absolute zero.
Last week, they told a meeting of physicists in Long Beach, California, that they found the speed of light is independent of direction to within 1.7 parts in 1015…
