I Didn’t Know That. . .

Q: When you turn on a flashlight or the headlights of a car, does the light accelerate to “light speed,” or is it somehow emitted at that speed?

A: According to physicist Ken Libbrecht of Caltech, light always travels at “light speed,” whether it has just been turned on or not. That postulate was first predicted by Albert Einstein as part of the theory of relativity, and many experiments have shown that the postulate is accurate, Libbrecht said.