Can Gravity Increase with Depth?
A debate is raging in our office regarding the change in gravity on an object as it moves from the surface of the earth to its center. We hope you can help us resolve this life and death issue. Given that the earth’s mass is NOT uniformly distributed, is it possible that the gravitational force can actually increase as a body moves just below the earth’s surface before it starts to diminish as it approaches the center? Personally, I would think so. The logic being that if I assumed that the mass of the upper crust were zero, the closer the object moves towards the core the greater the gravitational pull (till the object penetrates the core). Ron Reply π Dear Ron That is some neat question you have asked, and your qualitative argument is absolutely right. A short calculation (using some elementary calculus) makes it more precise. Suppose we are at a distance R from the center, the local density is D(R), and we move a test mass m downward by a small distance dR. If G is the constant of g
