Mirage at Sandy Hook
( illustration to chapter "Reflection and Refraction of Light" )
Two snaps below I took during my walk at Sandy Hook this Fall. They are differ only in a point of observation of the same hills on horizon. It was only a few steps from one point to another and not more than feet of elevation difference. As you see the difference is significant. Hills are reflected at the hot air layer, more over, part of them even vanished. The layer of hot ( and less dense) air near sand creates a mirage.
The phenomenon that causes objects to appear out of place, usually in desert or at sea, is the result of atmospheric conditions. When heat radiates from a hot earth surface, as in a desert, it causes a diminution of the density of the air just above the surface and forces a denser layer of air to remain above the hot, rarefied air instead of, as is usually the case, below it. The boundary between the two layers produces a lens-like effect and refracts or bends rays of light from a distant object; it also gives the appearance of a layer of water . The image produced by the rays bent by abnormal vertical distribution of air density appears inverted and below the real object, just as an image reflected in water appears when observed from a distance. A common experience of this phenomenon is the mirrored reflection of objects on a paved road in hot weather.
"Mirage." Microsoft® Encarta® Encyclopedia 2001. © 1993-2000 Microsoft Corporation. All rights reserved.
