Amazing Sky

The sky (or celestial dome) is everything that lies a certain distance above the surface of the Earth, including the atmosphere and outer space. In the field of astronomy, the sky is also called the celestial sphere. During daylight, the sky appears to be blue because air scatters blue sunlight more than it scatters red.  At night, the sky appears to be a mostly dark surface or region scattered with stars. During the day, the Sun can be seen in the sky, unless obscured by clouds. In the night sky (and to some extent during the day) the moon, planets and stars are visible in the sky.  Source