Question

The sky appears dark instead of blue to an astronaut. State its reason.(Delhi - 2012)

Answer 1

this is because at such huge nights of astronaut there is nothing to scatter the sunlight. therefore the sky appears dark

Answer 2

Because for an astronaut there is no atmosphere in space which can scatter light.

• Violet light has the shortest wavelength and the highest frequency in the visible light spectrum. It is scattered more than red light which has the longest wavelength and the shortest frequency. So, when the Sun is in the sky, violet light is scattered in all directions as sunlight passes through the atmosphere. But our eyes are more prone to blue light than violet. So we see the sky as blue (actually indigo).
• But for an astronaut there is no atmosphere in space for which the light can scatter. Absence of atmosphere results in not scattering of light and as no light scatters the astronaut sees the sky in space as black instead of blue.