Question

why does the sun appear reddish early in the morning?
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Answer 1

When sun's light travels a long distance in vacuum and when it enters the atmosphere due to the fine particles in the atmosphere the light with high wave length enter and others are scattered in space. This is mainly due to atmospheric refraction.

Answer 2

Early morning,during sunrise the sun is near to the horizon and very far from us. When sun's light passes through atmosphere, the particles present in the atmosphere scatters the light of short wavelength i.e., blue. Thus blue light is scattered away and the light which reaches to us is of the longer wavelength that is red. hence in early morning,the sun appear reddish due to atmospheric refraction.