Does anyone know or is it possible to know how much percent of earths motion is due to the effect of suns gravity? Im thinking very close to 100%, but not exactly 100%. If it were 100%, the earths orbit would be a perfect circle; not to mention the orbits or the other planets. So what causes the orbits to be eliptical? Elipcies have 2 focul points. The suns one, whats the other?