What color is the sky during the day when are no clouds?
There are differant colors at differant times of the day. The sky is (roughly) that part of the atmosphere or of outer space visible from the surface of the earth (or any other planet; see Skies of other planets). Birds, airplanes, and kites are often considered to fly in the sky. It is difficult to define precisely for several reasons. During daylight the sky has the appearance of an opaque blue surface, but this is the result of the air scattering sunlight. There is no “blue object” above the earth in any normal sense, so it is hard to say what object the sky is. The sky is thus 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. But if we then say that the sky is the entire visible universe, it would not be the same thing we see during the day. The color of the sky is a result of diffuse sky radiation. On a sunny day the Earth sky usually looks as a blue gradient – dark in the z
