Question

Why do the sky appears dark instead of blue to the astronauts?

Answer 1

There is no atmosphere in the outer space. We see the sky blue because scattering happens due to the particles in the atmosphere. The reason for scattering of light is the colloidal particles in the atmosphere which refract the light in different directions. When the blue light is refracted, this light comes to our eyes and thus the sky appears blue. Whereas, in space, as there is no atmosphere, light cannot be scattered. Due to this the sky appears dark to an astronaut.