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The lines represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of Earth is centered and vertical. The dense clusters of lines are within Earth's core. [2]
The dense clusters of lines are within the Earth's core. [27] The magnetic field of the Earth, and of other planets that have magnetic fields, is generated by dynamo action in which convection of molten iron in the planetary core generates electric currents which in turn give rise to magnetic fields. [15]
The north magnetic pole, also known as the magnetic north pole, is a point on the surface of Earth's Northern Hemisphere at which the planet's magnetic field points vertically downward (in other words, if a magnetic compass needle is allowed to rotate in three dimensions, it will point straight down).
This image shows magnetic declination, or the angle between magnetic and geographic north, according to the World Magnetic Model released in 2025. Red is magnetic north to the east of geographic ...
The magnetic field of a magnetic dipole has an inverse cubic dependence in distance, so its order of magnitude at the earth surface can be approximated by multiplying the above result with (R outer core ⁄ R Earth) 3 = (2890 ⁄ 6370) 3 = 0.093 , giving 2.5×10 −5 Tesla, not far from the measured value of 3×10 −5 Tesla at the equator.
If the Earth's magnetic fields were exactly dipolar, the north pole of a magnetic compass needle would point directly at the North Geomagnetic Pole. In practice, it does not because the geomagnetic field that originates in the core has a more complex non-dipolar part, and magnetic anomalies in the Earth's crust also contribute to the local ...
However, the Earth’s magnetic north is constantly influenced by the planets roiling iron core, which produces the entire magnetic field. As a result, magnetic north is always changing, and since ...
Relative to Earth's surface, the geographic poles move by a few metres over periods of a few years. [3] This is a combination of Chandler wobble , a free oscillation with a period of about 433 days; an annual motion responding to seasonal movements of air and water masses; and an irregular drift towards the 80th west meridian . [ 4 ]