Question

Why do stars twinkle on a clear night?

Answer 1

Stars are distant, self-luminous bodies.Their light is refracted by the atmosphere, which causes them to sparkle. Because the various air layers in the atmosphere have differing optical densities, light from stars refracts several times and in random directions when it enters the atmosphere. Stars appear to move somewhat as a result of this random refraction, which humans perceive as twinkling.