Sky Wallpaper, #12675

The Sky is the part of the atmosphere or of outer space visible from the surface of any astronomical object. It is difficult to define precisely for several reasons. During daylight the Sky of Earth has the appearance of a deep blue surface, as the result of the air's scattering of sunlight. The Sky is sometimes defined as the denser gaseous zone of a planet's atmosphere. At night the Sky has the appearance of a black surface or region scattered with stars.In the field of astronomy, the Sky is also called the celestial sphere. This is an imaginary dome where the sun, stars, planets, and the moon are seen to be travelling. The celestial sphere is divided into regions called constellations.The Sky can turn a multitude of colors such as red, orange and yellow (especially near sunset or sunrise) and black at night. Scattering effects also partially polarize light from the Sky.