. Explain giving reason why the sky appears blue to an observer from the surface of the earth

Best Answer

Ans. Sky' appears blue. The molecules of-air and other fine particles in the atmosphere have a size smaller than the wavelength  of visible light. So these particles scatter more effectively the light rays of shorter wavelength at the blue end than light of longer wavelengths at the red end.  When the scattered blue light enter our eyes, it gives  us the feeling  of a blue sky.                                                                                               

Colour of sky to an astronaut. There is no atmosphere containing air in space to scatter sunlight.  As there is no scattering of light in space, the scattered light , does not reach the eyes and  the sky appears dark instead  of blue to an astronaut  in outer  space.