Spherical projection wraps an image around a surface as if you were stretching a flat piece of rubber around a ball, but without having to worry about the edges all meeting. Planets, basketballs, and marbles could all use Spherical projection.
Spherical projection does not use Scale parameters. Images are wrapped completely around the surface (using the Wrap values, discussed later). Spherical projection is always oriented so that the top of the image appears toward the positive side of the Texture Axis.