mirage


Also found in: Dictionary, Thesaurus, Medical, Acronyms, Wikipedia.

mirage

(mĭräzh`), atmospheric optical illusion in which an observer sees in the distance a nonexistent body of water or an image, sometimes distorted, of some object or of a complete scene. Examples of mirages are pools of water seen over hot desert sand or over hot pavement; at sea, an inverted image of a ship seen in the heavens or, also at sea, some object that is actually over the horizon but seems to loom up a relatively short distance away. These phenomena can be explained by the facts (1) that light rays undergo refraction, i.e., are bent, in passing from a medium of one density into another of different density and (2) that the boundary between two such media acts as a mirror for rays of light coming in at certain angles (see reflectionreflection,
return of a wave from a surface that it strikes into the medium through which it has traveled. The general principles governing the reflection of light and sound are similar, for both normally travel in straight lines and both are wave phenomena.
..... Click the link for more information.
). Ordinarily the density of the atmosphere gradually decreases with altitude. Variations in temperature disturb the normal state (the density of warm air is less than that of cold air), producing unusual variations in the density of the atmosphere. The "lake" mirage in the desert is essentially a reflection of the sky. Light rays coming at a grazing angle from the sky just above the horizon are thrown upward by the surface of the area of extremely hot air just above the sand, and the effect to an observer is a shimmering reflecting expanse resembling the surface of a body of water. The inverted image of a ship seen in the heavens at sea is caused by a layer of dense, cool air over the water; this layer bends the rays of light from the ship (below the horizon) in a curved path that arches over the horizon and back to earth. The image formed appears to be that produced by an object somewhere distant in a straight line from the observer and, therefore, at a position in the sky. It is sometimes inverted because in the bending process the light rays coming from the object are changed in relative position. The type of mirage described as looming, in which distant objects appear much nearer than they actually are, is explained in the same way as the image of the ship, except that the image is not inverted; the density variations may also act as a magnifying glass. Mirages can be photographed. The strange phenomenon known as the fata morgana [Ital.,=Morgan le Fay, of the Arthurian legend, the supposed author of the mirage] is a complex mirage especially in evidence at the Strait of Messina; in this mirage images of objects such as ships, houses, or men, often two of the same object with one inverted, are seen suspended in the air over the object itself or on the water.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Mirage

 

an optical phenomenon in the atmosphère in which, in addition to a distant object (or part of the sky), a virtual image that is displaced with respect to the object can be seen. If the object is below the horizon, only the virtual image is seen. A mirage may be located below the object (inferior mirage), above the object (superior mirage), or to the side of the object (lateral mirage).

Mirages are explained by bending of rays of light from an object as a result of anomalous distribution of the index of refraction of light in the atmosphere, which is caused by the temperature distribution (and, consequently, density distribution) of the air. A superior mirage is observed above the cold surface of the earth during a temperature inversion (increased temperature with altitude); an inferior mirage is observed when there is a very high temperature gradient (that is, a sharp temperature drop with altitude) above a heated flat surface, such as a desert or a road. In such cases the virtual image of the sky creates in the process the illusion of water on the surface. For example, on a hot summer day a road receding into the distance looks wet. A lateral mirage is sometimes observed from greatly heated walls or rocks. Complex mirages with sharp distortion of the shape of objects are called fata morgana.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

mirage

[mə′räzh]
(optics)
Any one of a variety of unusual images of distant objects seen as a result of the bending of light rays in the atmosphere during abnormal vertical distribution of air density.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

mirage

As it pertains to radar, a refraction phenomenon in the atmosphere in which an image of some object is made to appear displaced from its true position.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

mirage

something illusory, such as an imaginary tree and pond in the midst of a desert. [Pop. Usage: Misc.]
Allusions—Cultural, Literary, Biblical, and Historical: A Thematic Dictionary. Copyright 2008 The Gale Group, Inc. All rights reserved.

mirage

an image of a distant object or sheet of water, often inverted or distorted, caused by atmospheric refraction by hot air
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Till such time as he proves his credentials and walks the talk, I am constrained to feel that we are now heading in to Mirage.2.
Despite being an entrylevel model, the Mirage 3 is a reasonably well-specified vehicle, with air conditioning, 14in alloy wheels, LED rear lamps and a rear spoiler.
indicola treated with Pronil and Mirage for 8 h caused less than 97% mortality in 8 h.
The Mirage's interior also features full climate control air-conditioning, GPS navigation and individual headrests for all occupants.Since it's a hatch, the Mirage's rear seats can be folded in a 60/40 split to open up more cargo space.
The Mirage Solo comes with 5.5-inch LCD displays with each having a screen resolution of 1,280x1,440 per eye.
Eleanor Joslin, manager of Mirage Project Point Dubai, commented: "We were thrilled by the response we had to our debut programme of talks at the Project Point, and the positive feedback we received from visitors about the space, with many registering their interest in using the venue for workshops, hot-desking, and talks - which is what it's designed to offer."
Summary: 15 Mitsubishi Mirages are available for each emirate.
The OBOGS system is one of the sensitive sections of Mirage fighters which adjusts the oxygen level of the pilot's cockpit in different altitudes.
The setting sun is therefore a mirage, but when most people think of a mirage, they think of a weary traveller crossing a desert and seeing a sparkling lake in the distance.
Tokyo, Nov 28, 2014 - (JCN Newswire) - Mitsubishi's Mirage hatch ES has been named the 'Best Micro Car' in the 2014 Australia's Best Car awards.
BAGHDAD / NINA / France announced on Sunday the arrival of the Mirage planes to Jordan for the start of military operations against the IS in Iraq.
Commenting on the offer, an official of GAC, said, "Since its launch earlier this year, the Mirage has received a terrific response from both customers and fans who have applauded its stylish looks and its balance of performance, safety and fuel efficiency.