The word sky comes from the Old Norse sky, meaning 'cloud, abode of God'. The Norse term is also the source of the Old English scēo, which shares the same Indo-European base as the classical Latin obscūrus, … See more

Except for direct sunlight, most of the light in the daytime sky is caused by scattering, which is dominated by a small-particle limit called Rayleigh scattering. The scattering due to molecule-sized particles (as in air) is greater in t… See more

The brightness and color of the sky vary greatly over the course of a day, and the primary cause of these properties differs as well. When the Sun is well above the horizon, direct scattering of sunlight (Rayleigh scattering) … See more