Question

Why does the sky appear to be black in night sky

Answer 1

the black sky at night that shows you the moon and stars is due to the absence of sun's light . the overwhelming effect of the sun's light
reacting with the atmosphere black out the blackness of the sky this means therefore that because there are no scattered light to reach the eyes of an observer during the night we get clear view of space , which is black

Answer 2

The blue color of the sky is a result of this scattering process. At night, when that part of Earth is facing away from the Sun, space looks black because there is no nearby bright source of light, like the Sun, to be scattered.