Scientists have a new theory which predicts the possibility of an engine powered by the fields found in a quantum vacuum. Includes this bon mot: Of course, nobody is getting a free lunch here. "Although the proposed engine will consume energy for manipulation of the particles, the propulsion will occur without any loss of mass," says [Alex Feigel at the Soreq Nuclear Research Center, a government lab in Yavne Israel]. He even suggests, with masterful understatement, that this might have practical implications. Ya think???