In developing his models for orbits and for classical gravity, Newton used the center of mass, a concept he inherited from antiquity, but as he used it, the center of mass inadvertently became a heuristic...where heuristics are rules of thumb, approximations or simplifications. We show that Newton's models for orbits and gravity are heuristics rather than the exact physics.In addition, in developing his gravitational model, there is another error, which occurred because he used a heuristic…
