Question

why does the clear sky appear blue ? how would the skyappear in the absence of earth's atmosphere?

Answer 1

A clear cloudless day-time sky is bluebecause molecules in the air scatter bluelight from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.

Answer 2

Our earth is surrounded by an atmosphere which have tiny water droplets. Also, a layer which separates the earth atmosphere from the space.

Hence, any light coming from space have to pass through these two devotions and which results to refraction.

This refraction here results to bending of blue light only and hence, sky appears blue.

If there will be no atmosphere ut means that there is no refraction of light and hence no refraction.

This will only give black sky!