THERMODYNAMICS:
Backward Heat Flow Bends the Law a Bit
Mark Sincell
A space-borne experiment has for the first time accomplished what the second law of thermodynamics seems to forbid: transfer of heat from a cold surface to a hot liquid. By warming a cell filled with a drop of a liquid and one tiny bubble of a gas in near-zero gravity, scientists on the space station Mir triggered a slight compression of the bubble, thereby raising the temperature of the gas above that of the cell walls. For this to happen, heat must have been transferred from the cooler walls to the hotter gas, the researchers report in the 1 May Physical Review Letters.