In the field of astronomy, the sky is called the celestial sphere.
It is the appearance of the atmosphere around the surface of the
planet.
The sky is made up of gas molecules. It is blue because of the
random scattering of sunlight by the molecules. Depending on the time of
day, the sky may appear different colors.
Many things can be seen in
the sky. There are objects from spacke like the Sun, Moon and Stars.