radiation pressure The minute pressure exerted on a surface at right-angles to the direction of travel of the incident electromagnetic radiation. Its existence was first predicted by James Maxwell in 1899 and demonstrated experimentally by Peter Lebedev. In quantum mechanics, radiation pressure can be interpreted as the transfer of momentum from photons as they strike a surface. Radiation pressure on dust grains in space can dominate over gravity and explains why the tail of a comet always points away from the Sun. Related entries space sail panspermia Related category OPTICS AND OPTICAL PHENOMENA Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |