Can anybody explain to me the phenomenon of MIRAGE?????

Question

Can anybody explain to me the phenomenon of MIRAGE?????

Answer 1

Mirage Phenomenon

Answer 2

A mirage is a naturally-occurring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes from the Latin mirare, meaning 'to appear, to seem'. This is the same root as for mirror. Like a mirror, a mirage shows images of things which are elsewhere. The principal physical cause of a mirage, however, is refraction and not reflection.



A mirage is not an optical illusion. It is a real phenomenon, and one can take photographs of it. The interpretation of the image, however, is up to the fantasy of the human mind.

Answer 3

it is the sam effect of heat on say you car roof. the image is reflected off the atmosphere and looks to be real.









A mirage is a naturally-occurring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes from the Latin mirare, meaning 'to appear, to seem'. This is the same root as for mirror. Like a mirror, a mirage shows images of things which are elsewhere. The principal physical cause of a mirage, however, is refraction and not reflection.



A mirage is not an optical illusion. It is a real phenomenon, and one can take photographs of it. The interpretation of the image, however, is up to the fantasy of the human mind.

Answer 4

A mirage is a naturally-occurring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky.



A mirage is not an optical illusion. It is a real phenomenon, and one can take photographs of it. The interpretation of the image, however, is up to the fantasy of the human mind.



Learn all about it @ this link:

Answer 5

Mirage is an optical illusion caused by two atmospheric phenomena, first-atmospheric refraction and second- total internal reflection. Suppose u r in a desert, and at some distance u see water but when u go there, u find nothing. This is called mirage or mrigtrushna. Actually what u saw was a piece of sky. Air near land is hot, and air away from he land is cold. So contact of both these air acts as a mirror. And refraction takes place due to difference in densities of different layers of air that is due to temperature. Got it.......

Answer 6

On hot summer days, the air near the ground is heated by earth. The air well above the earth is colder than the air near to the ground.



When sun’s rays pass through air and reaches the ground, the earth gets heated much than air is heated. Hot earth sends heat rays to the air. The air can absorb this heat efficiently than the heat given by the Sun.



Thus the temperature of air is gradually decreasing in value as the distance from the surface of ground is increasing.



A ray from the top of a distant tree or building, while passing through different layers of air, does not go straight. It bends toward the colder layer. Finally it becomes horizontal and then it travels from hot air to cold air again not in a straight path but in a curved path.



When such a ray reaches our eye, we sense it as if it is coming from the bottom of the ground. That is as if the object is reflected over some water surface. This phenomenon is called mirage.

Answer 7

(sorry tried 2 download da pic 2 but couldnt)

Mirage

On still, hot summer days in deserts, the surface

of sand is strongly heated by the Sun. The

apparent inverted images of distant objects (or

parts of the sky) are commonly observed on the

sand in hot deserts. These images are

sometimes mistaken by the thirsty travellers and

animals, as if formed by reflection from some

distant spurious lake or pool of water. But when

they approach the region, they find no water

there. They are misled by this optical illusion,

called a mirage. Mirages on a small scale are

very frequently observed as an illusion of a wavy

water surface over coal-tarred roads or smooth

concrete highways on hot summer days. The

apparent appearance is that of reflection from

water on the road ahead, which disappears on

closer view. A mirage occurs due to total internal

reflection of light by atmospheric refraction

upward.

On still summer days, the hotter air near

the earth’s surface is less dense, and so, has a

slightly smaller refractive index than the cooler

air above it. Light travels faster in the rarer,

hotter air than the denser, cooler air. So, the

light rays coming from the point A of a distant

tall object, such as a tree (Fig. 3.12), pass

through air of gradually decreasing refractive

index towards the earth (ground). Hence, the

light rays bend gradually more and more

obliquely away from the normal, till at a pointC,

they get totally internally reflected. Then the

light rays start traversing air regions of

increasing refractive index. So, they bend

gradually more and more towards the normal,

so that they are refracted upwards and appear

to come from the point A'. Therefore, the

observer sees an inverted image A'B' of the object,

below the ground. This apparent reflected image

may produce the deceptive or erroneous

impression as if it is reflected from the surface

of a pool of water, although no such water exists

there.

Another type of the mirage, called looming,

is sometimes observed when warmer air lies

above the cooler air, as would be the case over a

body of cold water or a snow field, especially in

Arctic regions. Rays of light from a distant object

are refracted downward.





Fig. 3.12 : Mirage is formed due to the total internal

reflection of light by atmospheric refraction upward.













Fig. 3.13 : Looming is caused by atmospheric

refraction downward.

In very cold regions, sometimes an erect,

virtual image of a distant object is seen above

the object. For example, a ship moving in the

sea is observed to be hanging in mid-air, above

the ship itself. Sometimes, the curvature

(bending) of the light rays may tend to bring into

view objects normally below the horizon

(Fig. 3.13).

Warm air

(Denser)

(Rarer)

Cool air

Answer 8

Obviously, your Definition of "Quite Clear" and mine differ significantly. This is a few smudges on a curtain and neither proves nor signifies anything at all.

Answer 9

A mirage is a naturally-occurring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes from the Latin mirare, meaning 'to appear, to seem'. This is the same root as for mirror. Like a mirror, a mirage shows images of things which are elsewhere. The principal physical cause of a mirage, however, is refraction and not reflection.



A mirage is not an optical illusion. It is a real phenomenon, and one can take photographs of it. The interpretation of the image, however, is up to the fantasy of the human mind.



Cause

The cause of an inferior mirage (light curvature strongly exaggerated)

Enlarge

The cause of an inferior mirage (light curvature strongly exaggerated)



Cold air is denser than warm air, and has therefore a greater refractive index. As light passes from colder air to warmer air it bends away from the direction of the temperature gradient (the "normal" in the figure at right); when it passes from hotter to colder, it bends towards the direction of the gradient. The diagram on the right shows a light ray coming from the sky toward the hot ground. If the air near the ground is warmer than that higher up, the light ray bends in a concave upwards trajectory. Once the ray reaches the viewer’s eye, the eye traces it as the line of sight, which is the line tangent to the path the ray takes at the point it reaches the eye. The result is that an inferior image for the above sky appears on the ground. The viewer may incorrectly interpret this sight as water reflecting the sky. In the case where the air near the ground is cooler than that higher up, the light rays will of course curve downwards, producing a superior image.



The 'rest' state of the Earth's atmosphere is with a vertical gradient of about -1 degree Celsius per 100 metres height. (The value is negative because it gets colder when you go higher.) For an actual mirage to happen, the temperature gradient has to be much greater. According to Minnaert[1] the magnitude of the gradient should be at least 2°C per metre, and the mirage will not get strong until the magnitude reaches 4 or 5°C per metre. These conditions can occur when there is strong heating at ground level, for example when the sun is shining on sand or asphalt.



[edit] Inferior mirage



The model given above explains the cause of the inferior mirage, called inferior because the image seen is under the real object. The real object is the (blue) sky or any distant object in that direction, meaning we see a bright bluish patch on the ground in the distance. For exhausted travellers in the desert it appears as a lake of water. On tarmac roads it may seem that water or even oil has been spilled. This is called a desert mirage or highway mirage. Note that both sand and tarmac can become very hot when exposed to the sun, easily being more than 10°C hotter than the air one centimetre above, enough to cause the mirage.



Light rays coming from a particular distant object all travel through nearly the same air layers and all are bent over about the same amount. Therefore rays coming from the top of the object will come less high than those from the bottom. The image usually is upside down, enhancing the illusion that the sky image seen in the distance is really a water or oil puddle acting as a mirror.



Inferior images are not stable. Hot air rises, and cooler air (being more dense) descends, so the layers will mix, giving rise to turbulence. The image will be disformed accordingly. It may be vibrating, it may be vertically extended (towering) or horizontally extended (stooping). If there are several temperature layers, several mirages may mix together, perhaps causing double images. In any case, mirages are usually not larger than about half a degree high (same apparent size as the sun and moon) and from objects only a few kilometres away.



[edit] Highway mirage



A highway mirage (asphalt mirage, hot road mirage or road mirage) is an inferior mirage seen on hot roadways on sunny days. The sun warms the black asphalt, heating the air above. Warm air is less dense than cool air, and the variation between the hot air at the surface of the road, and the denser cool air above it creates a gradient in the refractive index of the air. Light from the sky at a shallow angle to the road is refracted (bent) by the index gradient, making it appear as if the sky were reflected by the road's surface. The result looks like a pool of water on the road, since water also reflects the sky.



[edit] Superior mirage

Trees shown which are normally invisible below horizon, a superior mirage refracted from above

Enlarge

Trees shown which are normally invisible below horizon, a superior mirage refracted from above

Sunrise first light caused by super-refracted sunlight

Enlarge

Sunrise first light caused by super-refracted sunlight

Double sun sunrise caused by a super-refracted sun

Enlarge

Double sun sunrise caused by a super-refracted sun



A superior mirage occurs when the air below the line of sight is colder than that above. This is called a temperature inversion, since it does not represent the normal equilibrium temperature gradient of the atmosphere. Since in this case the light rays are bent down, the image appears above the true object, hence the name superior. They are in general less common than inferior mirages, but when they do occur they tend to be more stable, as cold air has no tendency to move up and warm air no tendency to move down.



Superior mirages are most common in polar regions, especially over large sheets of ice with an uniform low temperature. They also occur at more moderate latitudes, however, although in that case they are weaker and not so smooth. For example a distant shoreline may be made towering, looking higher (and thus perhaps closer) than it is in reality, but because of the turbulences there seem to be dancing spikes, towers and so forth. This type of mirage is also called the Fata Morgana or in Icelandic halgerndingar.



Superior images can be straight up or upside down, depending on the distance of the true object and the temperature gradient. Often the image appears as a distorted mixture of up and down parts.



If the Earth were flat, superior images would not be interesting. Light rays which bent down would soon hit the ground, and only close objects would be affected. Since the Earth is round, if the amount of downard bending is about equal to the curvature of the Earth, light rays can travel large distances, perhaps from beyond the horizon. This was observed for the first time in 1596, when a ship under the command of Willem Barents looking for the Northeast passage got stuck in the ice at Novaya Zemlya and the crew had to endure the polar winter there. They saw their midwinter night ending with the rise of a distorted sun about 2 weeks earlier than expected. It was not until the 20th century that Europeans understood the reason. That the real sun had still been under their horizon, but its light rays followed the curvature of the Earth. This effect is often called a Novaya Zemlya mirage. For every 100 km the light rays can travel parallel to the Earth's surface, the sun will appear 1° higher on the horizon. The inversion layer must have just the right temperature gradient over the whole distance to make this possible.



In the same way ships which are in reality so far away that they should not have been visible above the geometric horizon, may appear on the horizon, or even above the horizon as superior mirages. This explains stories about flying ships or coastal cities in the sky, as described by some polar explorers. These are examples of so called Arctic mirages or hillingar in Icelandic.



If the vertical temperature gradient is +11°C per 100 metres (reminder: positive means getting hotter when going up), horizontal light rays will just follow the curvature of the Earth, and the horizon will appear flat. If the gradient is less the rays are not bent enough, and get lost in space. That is the normal situation of a spherical, convex horizon. But if the gradient gets larger, say 18°C per 100 metres, the observer will see the horizon turned upwards, being concave, as if he were standing on the bottom of a saucer.

Answer 10

it is a consequence of heat