I dont agree with that statement, as the electrons and protons (positive and negative/ attractive and repulsive) can arrange themselves without the need for 'gravity'. It is highly possible that the Earths own magnetosphere or that from other celestial bodies acting on the magnet could arrange the atoms charges and forces. It is also true that magnets can also be demagnetised and their poles switched. You can also magnetise other metals just by rubbing them with another magnet (when it isnt in molten form) which doesnt need a centre of gravity. The link I gave was mainly for illustration purposes, the views of centre of gravity are by the author, but certain parts such as the magnetic view of orbiting planets (
http://www.truesci.com/basic%20Magne...d%20space.html) is just illustrating my theory better than words.