meteor

A meteor is the visible path of a meteoroid that enters the Earth's (or another body's) atmosphere, commonly called a shooting star or falling star. For bodies with a size scale larger than the atmospheric mean free path (10 cm to several meters) the visibility is due to the heat produced by the ram pressure (not friction, as is commonly assumed) of atmospheric entry. Since the majority of meteors are from small sand-grain size meteoroid bodies, most visible signatures are caused by dexcitation following the individual collisions between vaporized meteor atoms and atmospheric constituents.