why do mirages disappear as you get closer
Answers
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.
During a hot summer day, air just above the road is very hot and the air at higher altitudes is cool.
It means that the temperature decreases with height. As a result the density of air increases with height.
We know that the refractive index of air increases with density. Thus the refractive index of air increases with height.
So the cooler air at the top has greater refractive index than the hotter air just above the road.
Light travels faster through the thinner hot air than through the denser cool air above it.
When light from a tree passes through a medium just above the road, whose refractive index decreases towards the ground, it suffers, refraction and takes a curved path because of total internal reflection.
This appears to the observer as if the ray is reflected from the ground. Hence we feel the illusion of water being present on the road.
The inverted virtual image of the tree is seen by the observer. This is a mirage.
Answer:
Because mirages don't exist really. these are only hope or wish that can not be achieved.