Re:The moon's gravity is 1/81st, not 1/6th (Score 1)

You are correct regarding the relationship of the mass of the moon to the earth is correct, but the "gravities" at the surface are not proportional. It has to do more with the radius from the surface to the center of the planet/moon/object. For an example, Jupiter is 318 of times the mass of the earth, but the "gravities" on the surface are only 2.36G's(somewhere around there), this is because the planet is composed of mostly light gasses and the radius is 71,492 km compared to earth's 6,378km. The moon is lighter than the earth, but at the surface you are closer to the center of mass than the earth as the moon is 1/4 the diameter. I don't have the all the figures with me, but it seems to be a measure of mass to the distance from the center. Sorry for the long explanation, I'm new here.