<P> In some situations, distant objects can get elevated or lowered, stretched or shortened with no mirage involved . </P> <P> A Fata Morgana, the name of which comes from the Italian translation of Morgan le Fay, the fairy shapeshifting half - sister of King Arthur, is a very complex superior mirage . It appears with alternations of compressed and stretched zones, erect images, and inverted images . A Fata Morgana is also a fast - changing mirage . </P> <P> Fata Morgana mirages are most common in polar regions, especially over large sheets of ice with a uniform low temperature, but they can be observed almost anywhere . In polar regions, a Fata Morgana may be observed on cold days; in desert areas and over oceans and lakes, a Fata Morgana may be observed on hot days . For a Fata Morgana, temperature inversion has to be strong enough that light rays' curvatures within the inversion are stronger than the curvature of the Earth . </P> <P> The rays will bend and create arcs . An observer needs to be within an atmospheric duct to be able to see a Fata Morgana . Fata Morgana mirages may be observed from any altitude within the Earth's atmosphere, including from mountaintops or airplanes . </P>

Mirage is formed due to the effect of