Posted: November 28th, 2022
A mirage is an optical phenomenon
A mirage is an optical phenomenon that creates the illusion of water and results from the refraction of light through a non-uniform medium. When optical density of a refractive matter is non-uniform, then the refractive phenomenon forms a mirage. Air can sometimes form a non-uniform medium leads to an interesting refraction phenomenon - the formation of mirages (David, 2001).
An illusion in the mind as one walks along a road in a sunny day makes him or her perceive a pool of water, a mirror or a glass window few yards, say 100 yards, in front of him. Of course, when you reach the supposed location of the pool, you identify that the pool is not there. Instead, that pool of water appears to be an extra one-hundred yards ahead of you. These appearances of the water are simply an illusion.
The role of the sun in mirage development is to increase the roadway temperatures. The road warmth in turn heats the air above it, increasing the air temperature just above the roadway. Hot air is less dense optically than cooler air (David, 2001). As a result, a non-uniform medium is created by the roadway heating and air just above. Therefore, light will refract when traveling through a non-uniform medium. If a driver looks down at the roadway at a very low angle (that is, at a position nearly one hundred yards away), light from objects above the roadway will follow a curved path to the driver's eye. This leads to a mirage perception.
Reference
David K. Lynch & William Livingston (2001). An Introduction to Mirages (2nd ed.). Cambridge, UK: Cambridge University Press. p. 58.