Question

why do stars twinkle ?explain

Answer 1

Stars do not really twinkle, they just appear to twinkle when seen from the surface of Earth. The stars twinkle in the night sky because of the effects of our atmosphere. When starlight enters our atmosphere it is affected by winds in the atmosphere and by areas with different temperatures and densities.

Answer 2

The refractive index of the atmosphere changes with the temperature, the apparent position of The Star is not stationary but keeps on changing slightly. Thus the apparent position of The Star fluctuates and light from the star on entering the eye flickers. Hence, The Star sometimes appears bright and at some other time , appear dim. This is twinkling of stars.