The term ‘ablation’ can be used to refer to the process by which the surface layers of an object are eroded. Examples are friction (e.g. spacecraft entering the Earth’s atmosphere) and radiation (e.g. tumours being removed by laser).

In astronomy it is most commonly used to describe the vapourisation of the surface layers of meteors as they fall through the Earth’s atmosphere. The particles released ionise the surrounding atmospheric molecules, which later de-excite to produce the glowing trails commonly associated with this type of object.