Question

How does the refraction of light take place in the atmosphere? Explain the reason why stars appear to twinkle and the planets do not twinkle.

Answer 1

Answer:

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.

Explanation: