[Phoenix-D]

Originally posted by Kamog:
I never understood this idea of the earth's magnetic poles moving around. How can the magnetic field, which was stable for a long period of time, suddenly reverse polarity? If the magnetic field is produced by the flow of molten material inside the earth, then it takes a tremendous amount of energy to change the direction of flow for so much mass. Where does this energy come from? Also, I thought that a flow of material will not produce a magnetic field unless there's an electrical current flowing through it. I mean, if you take a piece of iron and move it around where there's no magnetic field, it's not going to produce its own magnetic field, would it?

The mouse is right- pretty much everything produces a magnetic field. Its just that in most objects, the fields aren't aligned, so they pull in different directions and cancel each other out effectively. Iron and certain other materials are different in that you can force their fields to all point the way way.

The reason for the fields is electrons. They're moving about the nucleus, and they carry an electric charge. ANY moving charge produces a magnetic field. And vice versa.