Scientists Watch as Heat Moves at the Speed of Sound

He had just performed a new experiment examining common graphite—the stuff of pencil lead—but the results seemed physically impossible: Heat, which typically disperses slowly, had traveled through the graphite at the speed of sound. First, Duncan deposited heat into the graphite sample using two crossed laser beams to create an interference pattern—alternating bright and dark regions that correspond to crests and troughs in the colliding waves of light. Not only is the temperature far more practical than the cryogenic chill required to work with the previous findings, but graphite is a commonplace material—two characteristics that might help engineers overcome the daunting issue of heat management in microelectronics today.

Source: www.scientificamerican.com