what's a kepler's equation
After applying Newton's Laws of Motion and Newton's Law of Gravity we find that Kepler's Third Law takes a more general form: where M 1 and M 2 are the masses of the two orbiting objects in solar masses. Note that if the mass of one body, such as M 1, is much larger than the other, then M 1 +M 2 is nearly equal to M 1. In our solar system M 1 =1 solar mass, and this equation becomes identical to the first. Example: Phobos orbits Mars with an average distance of about 9380 km from the center of the planet and a rotational period of about 7hr 39 min. Use this information to estimate the mass of Mars.