if the space is black in colour then why we see the sky blue? if our atmosphere layer is having blue colour?
The space appears black because it is of infinite size not having any particular body that can illuminate it completely. The bodies that illuminate the sky are the stars and planets that have hot gaseous properties. As of our atmosphere, it appears blue is because of the phenomenon called refraction. The sunlight that reaches earth, is made up of a bandwith of seven colours VIBGYOR. Violet light gets dispersed the most hence when sun light enters the atmosphere of earth, the violet band of the spectrum scatters and makes the sky seem as blue.