Sun's gravity well. Computer artwork of the Sun (orange) and Earth (blue), showing the Sun's gravity well as a distorted grid. A gravity well is the gravitational potential field around a massive body. It is the pull of gravity that bodies such as planets and stars exert on their surroundings. Gravitation is described by Einstein's general theory of relativity, in which the phenomenon itself is a consequence of the curvature of spacetime (grid) governing the motion of inertial objects.