Earth's magnetic field (also known as the geomagnetic field) is the magnetic field that extends from the Earth's inner core to where it meets the solarwind, a stream of energetic particles emanating from the sun. It is approximately the field of a magnetic dipole tilted at an angle of 11 degrees with respect to the rotational axis—as if there were a bar magnet placed at that angle at the center of the Earth. However, unlike the field of a bar magnet, Earth's field changes over time because it is really generated by the motion of molten iron alloys in the Earth's outer coreThe magnetic north pole wanders, fortunately slowly enough that the compass is useful for navigation. At random intervals earths field reverses . These reversals leave a record in rocks that allow paramagnets to calculate past motions of continents and ocean floors as a result of plate tectonics.
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