Poynting-Robertson effectAn effect of radiation pressure on a small particle orbiting a star that causes it to spiral slowly into the star. The radiation falls preferentially on the leading edge of the orbiting particle and acts as a drag force. For example, a dust grain one micron wide located at the position of Earth would spiral into the Sun in a period of about 3,000 years. Also called Poynting-Robertson drag. Related category OPTICS AND OPTICAL PHENOMENAAlso on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |