The distortion of an object's true image as the result of abnormal atmospheric disturbances along the path traveled by the light. The atmospheric disturbances common with mirages are a result of a variation of temperature in a given region. The index of refraction of air is dependent on the temperature, density, and other properties. When air resides over extremely hot objects such as jet engines, candle flames, or the asphalt of the road on a hot day the gradual change of temperature in the atmosphere close to such a hot object will cause the gradual change in the index of refraction and thus a gradual bending of light as it propagates through the air in these regions. When the air next to the object is significantly higher than the air above it, light passing through will tend to be bent so much that it appears reflected. This is a mirage. See fata morgana; inferior mirage; superior mirage.