For the smallest objects, such as moons and planets, no discrepancy exists. Earth’s surface gravity, for example, can be explained entirely by the stuff that’s under our feet. If you are overweight on Earth, don’t blame dark matter. Dark matter also has no bearing on the Moon’s orbit around Earth, nor on the movements of the planets around the Sun—but as we’ve already seen, we do need it to explain the motions of stars around the center of the galaxy.
