Celestial effects on the skin.

Many factors affect the health and physiology of human skin, with some of them arising from outer space. This contribution explores four celestial influences on the skin: (1) the sun's ultraviolet light, which has both beneficial and deleterious dermatologic effects, (2) meteorite injuries, (3) possible lunar effects on the body's health, and (4) cosmic radiation as a risk factor for skin cancer and pregnancy-related complications. Some of these extraterrestrial influences on skin health have taken on added significance as human beings increasingly spend more time at higher altitudes in aircraft, spaceships, and space stations.