Hi, I know potential = mgh where g can be considered constant close to the surface of the Earth. So as we move away from the Earth the h and P increase. And taking P = 0 @ infinity then P = -GMm/r so P < 0 always and increases to 0 as you move away from the Earth. So it seems there is no potential at infinity and even less as you get closer to the Earth! Is that correct? What if for P = -Gmm/r, I put P = 0 at the surface of the Earth as it is for mgh?