Question

How do twinkling stars occur? (or) what is the cause of the twinkling of stars?

Answer 1

Refraction of light:

1. Light from a star is refracted as it passes through our atmosphere because the light
   passes rapidly through moving cells of air with different densities, temperatures, etc.
2. These cells bend light by different amounts and make the apparent position of the star move around. This movement is seen as twinkling.