Earth's Magnetic Field

Claimed by Mclark78 (Matthew Clark)

Short Description of Topic

Bar Magnet Comparison

The Earth’s magnetic field acts much like a bar magnet with a north and South Pole. Our compass magnets’ north end will point to the north part of the Earth. But, magnets repel the same charged side, so why does north point north? This is because what we call the North Pole is the geographic north, but the magnetic south and the South Pole is the magnetic north pole. So, the magnetic field lines, if they were visible, would go from the geographic South Pole and curve up and into the geographic North Pole.

Electromagnet Comparison

Unlike a bar magnet, the Earth’s core is far too hot to be magnetic. It is hypothesized that there is electric current flowing in the Earth’s core and this is what generates the magnetic field. This is much like how an electromagnet works. Flowing electric current produces a magnetic field, like having a current go through a wire that is wrapped around a nail. It was from this know relationship and the understanding that the Earth’s core is molten metal and flowing, that lead to the current understanding of how the Earth’s magnetic field is generated.

Dynamo Effect

Now, the above explanation is a simplified one. The ‘’dynamo effect” is what is believed to cause the electric current that generates the magnetic field. Molten metal, like iron, follows the Earth’s magnetic field and generates the electric current. The metals’ interaction with each other produces a charge probably due to friction and convection drives the flowing of the molten metal. The convection is most likely due to radioactive decay within the Earth’s core and this in turn produces heat to generate the convection. Once the magnetic field from the flowing of molten metal is produced, it and the already produced magnetic field form an even stronger field along the Earth’s rotation. Also, the produced magnetic field will cause more flowing of the core which will then create another electric current which will then produce another magnetic field. This cycle continues and cause the Earth’s magnetic field to be self-sustaining. So, simplified convection causes the churning of the outer core and this forms a magnetic field which forms more electric currents to form more magnetic fields.

A Mathematical Model

What are the mathematical equations that allow us to model this topic. For example [math]\displaystyle{ {\frac{d\vec{p}}{dt}}_{system} = \vec{F}_{net} }[/math] where p is the momentum of the system and F is the net force from the surroundings.

A Computational Model

How do we visualize or predict using this topic. Consider embedding some vpython code here Teach hands-on with GlowScript

Examples

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Connectedness

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See also

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