Post
by Poppy » 05 Jun 2009, 16:56
This from wikipedia:
"A fata morgana, Italian translation of Morgan le Fay, the fairy shapeshifting half-sister of King Arthur, is a mirage, an optical phenomenon which results from a temperature inversion.
Fata Morgana are usually seen in the morning after a cold night which has resulted in the radiation of heat into space. In this form of mirage, objects on the horizon or even beyond the horizon, such as islands, cliffs, ships or icebergs, appear elongated and elevated, like "fairy tale castles".
This is how the mirage is caused: in calm weather, when warm air lies over cold dense air near the surface of the ground, the undisturbed interface between these two air masses can act as a refracting lens, producing an upside-down image, over which the distant direct image appears to hover.
The first mention of the "Fata Morgana" phenomenon in English was in 1818, when this type of mirage was observed in the Strait of Messina, between Calabria and Sicily. It is also commonly seen in high mountain valleys, such as the San Luis Valley of Colorado where the effect is exaggerated due to the curvature of the floor of the valley canceling out the curvature of the Earth. These mirages are also seen in Arctic seas on very still mornings, and are common on Antarctic ice shelves.
Fata Morgana are superior mirages. Superior mirages are distinct from the more common inferior mirages, which create the illusion of distant pools of water in the desert and on hot roads."