layers of radioactive materials lying very near the surface these materials however are too heavy to have floated up what then deposited them near the moon's surface the moon's gravity field appears to be erratic as though huge chunks of heavy matter such as iron had not evenly sunk to its core but were scattered about by what process or force we might ask there is evidence that the ancient rocks of the moon were magnetized but there is also evidence that the magnetic fields were changed or reversed was it by some