How was the earth magnetic field created?
Magnetic fields are produced by the motion of electrical charges. For example, the magnetic field of a bar magnet results from the motion of negatively charged electrons in the magnet. The origin of the Earth’s magnetic field is not completely understood, but is thought to be associated with electrical currents produced by the coupling of convective effects and rotation in the spinning liquid metallic outer core of iron and nickel. This mechanism is termed the dynamo effect. Rocks that are formed from the molten state contain indicators of the magnetic field at the time of their solidification. The study of such “magnetic fossils” indicates that the Earth’s magnetic field reverses itself every million years or so (the north and south magnetic poles switch). This is but one detail of the magnetic field that is not well understood. The Earth’s Magnetic Field – As we shall see in a subsequent section, the charged particles trapped in the Earth’s magnetic field are responsible for the auro
