Superposing tidal force fields

Abstract

The motion of the Earth relative to the Sun’s inertial frame of reference, is a superposition of the motion of the Earth around the common center of mass of the Moon and the Earth and the motion of that center of mass around the Sun. However, you get the resulting tidal force field due to the simultaneous existence of the Moon and the Sun by superposing a Moon- induced tidal force field and a Sun-induced tidal force field. Where, the Moon-induced tidal force field is calculated as if the Sun were not existing, and the Sun-induced tidal force field is calculated as if the Moon were not existing. The situation may lead to confusion. Thus, we give a formal conceptual account of the state of affairs, and argue that the case is useful when introducing undergraduates to inertial forces and understanding Newtonian mechanics.