Question

The sky appears dark instead of blue to an astronaut.Why?

Answer 1

Hint: Scattering of light is the phenomenon in which light rays get deviated from its straight path on striking an obstacle like dust or gas molecules, water vapors, etc. Scattering of light gives rise to many unusual occurring such as the Tyndall effect.

Complete step-by-step solution -
The sky appears blue when the scattering of light takes place. As there is no atmosphere in space and hence light does not scatter into its constituent colors that is why the sky appears dark instead of blue to an astronaut in space.
Additional information:
The wavelength of blue color is 450nm with a frequency of 6.66Hz
The distance between successive crests of a wave is known as wavelength.
We know that rate per second of a vibration that constitutes a wave, that is either in a material (as in sound waves), or in an electromagnetic field(as a light ray), is known as Frequency of a wave.
Atoms or molecules which are exposed to light absorb light energy and then re-emit light in different directions with different intensity. This phenomenon is an example of a scattering of light.
The scattering of light in a colloid or in a very fine suspension is known as the Tyndall effect.

Note: Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels in shorter, smaller waves. This is the phenomenon because of which we see a blue sky most of the time.