The wearing away or destruction of the outer or forward surface of an object, such as a meteorite or a spacecraft, as it moves very rapidly through the atmosphere. The friction of the air striking the object heats and often melts or burns its outer layers. Spacecraft and missiles are often equipped with heat shields designed to wear away by ablation in order to prevent heat from building up in structurally important parts.
The process by which snow and ice are removed from a glacier or other mass of ice. Ablation typically occurs through melting, sublimation, wind erosion, or calving. ◇ The ablation zone is the area of a glacier that has the lowest elevation, where annual water loss is greater than the annual accumulation of snow.