An Introduction to Mirage
Many of you have heard about it.
Some of you have seen it.
But only few of you knows about it.
Mirage is not an illusion,it’s a real optical phenonmenon of atmospheric optics, caused by strong ray-bending in layers with steep thermal gradients. Because mirages are real physical phenomena, they can be photographed.
Optical illusions, on the other hand, are perceptual quirks of human vision, in which the observer sees something that does not exist physically
Mirages can be categorized as
1)”inferior” (meaning lower)
2)”superior” (meaning higher)
3)”Fata Morgana”, one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage.
Mirages are phenomena of atmospheric refraction
Let us now understand what is refraction and some examples
Refraction:The bending of rays of light in passing from one medium to another (e.g., air to water), or between parts of the same medium with different densities (e.g., different levels in the atmosphere). The amount of refraction is given by Snel’s law, which is expressed in terms of the medium’s refractive index, which is just the ratio of the speed of light in a vacuum to that in the medium.
Some examples that shows refraction:
TWO CONCEPTS THAT HELPS EXPLAIN THE MIRAGE:
1) The Light travels the path which is shortest in time, not the shortest in distance. From Source to destination the light waves chooses that path which takes least amount of time to reach irrespective of the distance covered.
2) Our brain thinks that the light waves reaching to our eyes comes in a straight line.
Now keeping in mind the above two concepts i will try to explain a inferior mirage.
Let us take a scenario where we are travelling in a desert during summers with sunny sky.
Now during the summers the temperature of the ground or the sand may even reach to 80C .
This amount of temperature makes the layer of air just above the ground very hot . As we go up the atmospheric layer the temperature is relatively cooler.
This temperature difference creates a gradient. Since hot air above the ground is less denser than the cold air which is more denser.
Now as discussed above when there is a change of medium with difference of densities refraction phenomenon occurs and hence the light rays curves towards the cold air.
Now this is what actually happening
During normal conditions light rays from the sky comes in a straight line
But during hot conditions a layer of hot air and cold air is formed.
Now the light travels faster in hot air it bends towards downward and then moves towards cold air due to refraction.
Now our mind thinks that light travels in a straight line, so this cause our brain to think that the light is coming from the ground and the reflection is of water.
SO THIS EXPLAINS THE INFERIOR MIRAGE.
ITS FUNNY HOW OUR MINDS THINKS !
After all its a Beautiful Mind
Now i leave you with some pics of Mirage,just enjoy the illusion of our mind….