Asked by casahabulqamar | 29th Jan, 2015, 08:54: PM

Expert Answer:

A star appears twinkling in the sky.

Stars twinkle on account of atmospheric refraction, i.e., it bends from its actual path. Starlight undergoes refraction many times before entering the earth. It occurs because there is a gradual increase in the refractive index from the atmosphere to the Earth’s surface.

The apparent position of the star is different than the actual position due to refraction. 

Answered by Faiza Lambe | 30th Jan, 2015, 11:12: AM