NewScientist -- A US company claims it is ready to build a microwave ray gun able to beam sounds directly into people's heads. The device a dubbed MEDUSA (Mob Excess Deterrent Using Silent Audio) a exploits the microwave audio effect, in which short microwave pulses rapidly heat tissue, causing a shockwave inside the skull that can be detected by the ears. A series of pulses can be transmitted to produce recognisable sounds. The device is aimed for military or crowd-control applications, but may have other uses. Lev Sadovnik of the Sierra Nevada Corporation in the US is working on the system, having started work on a US navy research contract. The navy's report states that the effect was shown to be effective. Scarecrow Beam? MEDUSA involves a microwave...