OT: Earth's orbit changing?

[Fyron]

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 magnetic field is not stable. It never has been, and never will be, unless the earth cools down and becomes a hunk of rock. The field is always in flux, due to the aforementioned movements of the liquid magma that is the bulk of the Earth's mass. The magnetic field of the Earth is always slowly changing. It reverses every few thousand years. This does not cause any significant increase in the amount of radiation that reaches the Earth's surface.