Question

How does refraction take place in the atmosphere? why do stars twinkle but not the planets? ​

Answer 1

Hello

Stars twinkle on a clear night : The twinkling of a star is due to the atmospheric refraction of star's light. When the light coming from a star enters the earth's atmosphere, it undergoes refraction due to the varying optical densities of air at various altitudes.

Answer 2

Hi mate✌️

As we move above the earth’s surface, the density of air goes on decreasing. Light travelling from rarer to denser layers always bends towards the normal. Thus, the position of the object emitting light appears shifted.

Continuously changing physical conditions of atmosphere refracts light from the stars, which are considered as point sources, by different amounts from one moment to the other - when atmosphere refracts more starlight towards us the star appears to be bright and when the atmosphere refracts less starlight then the stars appears to be dim.

However the planets are nearer to us than the stars, and hence they can not be considered as point sources, hence no twinkling