Why do stars twinkle?

Why do stars twinkle?

The twinkling of the stars is actually a scientific phenomenon, which is known as stellar scintillation or astronomical scintillation. Scintillation or twinkling is a generic term used to describe the rapid variations in apparent brightness or color of a distant luminous object when viewed through the atmosphere of the earth. Wind motion, turbulent air and varying temperature scales in the atmosphere are some of the major factors that play a role in the refraction of light rays and hence the phenomenon of scintillation as well.

To understand this phenomenon you should first know some basic concepts in astronomy. The stars emit light in the form of light rays. The stars in the sky are visible to us because of the fact that these light rays travel through several layers of atmosphere that surrounds the earth. Earth's atmosphere is made up of several layers of gases that vary in their density.

Thus, when the light rays emitted by the stars travels through the atmosphere, they undergo refraction, which means they are bent. The degree of refraction depends on the density of the atmosphere. Owing to several layers of differential densities, the rays of light emitted from the stars are randomly refracted several times in random directions. This leads to the effect of "twinkling", which is merely an interpretation of refracted light by our eyes.