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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]
Kinematic dynamo theory was mainly a matter of trying different flow geometries and testing whether such geometries could sustain a dynamo. [63] The first self-consistent dynamo models, ones that determine both the fluid motions and the magnetic field, were developed by two groups in 1995, one in Japan [64] and one in the United States.
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.
These eddies develop a magnetic field which boosts Earth's original magnetic field—a process which is self-sustaining and is called the geomagnetic dynamo. [19] Reversals of Earth's magnetic field. Based on the MHD equations, Glatzmaier and Paul Roberts have made a supercomputer model of the Earth's interior.
This could weaken Earth's protective magnetic field by up to 90% during a polar flip. Earth's magnetic field is what shields us from harmful space radiation which can damage cells, cause cancer ...
During the transition, Earth's magnetic field declined to a minimum of 5% of its current strength, and was at about 25% of its current strength when fully reversed. This reduction in geomagnetic field strength resulted in more cosmic rays reaching the Earth , causing greater production of the cosmogenic isotopes beryllium-10 and carbon-14 , a ...
Earth’s outer core is made up of mostly molten iron, a liquid metal. Unpredictable changes in the way it flows cause the magnetic field around the Earth to shift, which then causes the magnetic ...
The emergence of a mysterious area in the South Atlantic where geomagnetic field strength is decreasing rapidly, has led some to speculate Earth’s magnetic poles are about to ‘flip’