This equation computes the rate of change of the argument of perigee, ω, of an orbit where the rate of change (.ωJ2) in deg/day results from the affect of the J2 geopotential coefficients derived from the geopotential function of the Earth. The inputs to this equation are:
The earth is not a sphere. In fact, the Earth is neither a homogeneous mass nor a sphere. Consequently, the several attributes of the Earth's shape and composition have noticeable affects on a satellite's orbit. The bulge at the equator, the flattening at the poles, and the slight pear shape of the Earth are important contributors to the perturbation of an orbit due to a non-spherical Earth.