Science: Measuring Up

As fast as the speed of light

The report from Paris sounded like a nonevent, yet scientists considered it major news. In a rare display of international comity, the 46-member General Conference on Weights and Measures unanimously redefined the meter, the world's basic unit of length.* Instead of being viewed simply as an arbitrary length, the meter will henceforth be defined in terms of another base measure, time—specifically, the distance light travels through space in 1/299,792,458 of a second.

One of physics' sacred constants, the speed of light is exactly 299,792,458 meters per second....

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