Does the Earth's magnetic field really reverse every few thousand years?

[alias25]

I heard that the Earth's magnetic field changes every few thousands of years? is this true, if it is how does that happen

 

[Deeviant]

The Earth's magnetic poles are in constant motion, moving in distances easily measured in just a year. This is the reason why magnetic compasses readings must be recalibrated over time.

I believe the best answer available today is that this is caused by some sort of shifting of the iron inside of earth.

 

[LURCH]

There is indeed geological evidence that the Earth's magnetic field reverses periodically. The cause for the reversal is not really understood, neither the cause for the field itself. There is a thread about ithere .

The thread is largely based on the work of Dr. Daniel Lathrop of University of Maryland.http://complex.umd.edu/dynamo/index.html .