Spherical harmonics are a set of mathematical functions defined on the surface of a sphere. They are widely used in various fields such as physics, computer graphics, and geodesy to represent and analyze functions on the sphere. Spherical harmonics are a generalization of the familiar trigonometric functions, such as sine and cosine, to the spherical domain. They have useful properties such as orthogonality, which makes them efficient for representing and decomposing signals on the sphere. Spherical harmonics are commonly used in applications such as spherical harmonic analysis, spherical harmonics lighting, and spherical harmonic mapping.