Spherical harmonics are functions that oscillate over the surface of a sphere. All the stars appear to lie on the imaginary Celestial sphere. The gravity depends only on the mass inside the sphere of radius . This is the principle behind the armillary sphere and the equatorial bow sundial. In antiquity, he was credited with inventing the first celestial sphere. The myth's religious importance extended beyond the funerary sphere. The surface area of this sphere is . Let us denote now the radius of the sphere as . This is done by projecting each solid onto a concentric sphere. Begin with a sphere centered on the origin. The Portuguese shield rests over the armillary sphere. The volume of a sphere of radius is . And the economics of its social sphere. There is a concern for religious institutions becoming active in the political sphere. Everything below the moon is part of the sublunary sphere.