How does Earth sustain its Mag Field?

In summary, Dynamo Theory explains how Earth's rotation induces a current in its molten, electrically conductive core. This current is caused by the movement of free electrons within the core, which creates magnetic fields. It is believed that convection cells in the fluid outer core play a role in generating these magnetic fields, but their counter-rotating nature causes them to cancel each other out, leaving a residual field that can change depending on changes in the convection cells. This theory is further explained in the provided link and is a topic more suitable for discussion in the Earth Science forum.
  • #1
morenogabr
29
0
Anyone want to try explaining Dynamo Theory to a 2nd year astrophy undergrad? Short and simple will do...
 
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  • #2
The Earth rotates and has a molten, metallic [electrically conductive] core.
 
  • #3
so what is it about the Earths rotation that induces the current in this conductive core?
 
  • #4
I do believe the core, since it is molten and conductive has a large number of free electrons moving around in it, and moving charges give rise to magnetic fields.
 
  • #5
It's thought that convection cells in the fluid outer core generate strong magnetic fields, but the different adjacent cells are assumed to counter rotate, almost cancelling out each others field. Only a residual field remains that can collapse or reverse depending on changes in the core convection cells.

That's the abstract of this:

http://www.psc.edu/science/glatzmaier.html

Better post these things in the Earth Science forum.
 

Related to How does Earth sustain its Mag Field?

1. How does the Earth's magnetic field protect us from solar radiation?

The Earth's magnetic field acts as a shield, deflecting the majority of charged particles from the sun that would otherwise harm living organisms on the planet's surface. This is because the magnetic field creates a protective barrier that forces the charged particles to flow around the Earth, rather than directly impacting it.

2. Why does the Earth's magnetic field change over time?

The Earth's magnetic field is constantly changing due to the flow of molten iron in the planet's outer core. This flow creates electric currents, which in turn generate the magnetic field. The movement of the molten iron is influenced by various factors, such as the Earth's rotation and the convection currents within the core, causing the magnetic field to fluctuate.

3. How does the Earth's magnetic field affect navigation?

The Earth's magnetic field plays a crucial role in navigation, particularly for long-distance travel. The magnetic field creates compasses, which use the field's direction and strength to determine direction. Without the magnetic field, it would be much more challenging to navigate using a compass, making long-distance travel much more difficult.

4. Can the Earth's magnetic field reverse its polarity?

Yes, the Earth's magnetic field has reversed its polarity numerous times in the past. This means that the magnetic north and south poles switch places, causing the direction of the magnetic field to flip. Scientists estimate that this reversal occurs every few hundred thousand years, with the last reversal happening approximately 780,000 years ago.

5. How does the Earth sustain its magnetic field?

The Earth's magnetic field is sustained by the constant flow of molten iron in the outer core. As long as this flow continues, the magnetic field will remain stable. However, the Earth's magnetic field is not completely constant, and changes in the flow of molten iron can cause the field to weaken or even reverse its polarity over time.

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