Talk:Geomagnetic field decay
It has been amusing to view the intellectual bun fight between Creationist and Atheist groups on this subject. As a professional electrical engineer I am intrigued by the ‘dynamo’ theory of the earth’s magnetic field.
The favourite theory for earth’s magnetism is that convection currents move electrical charges around and produce a magnetic field. Well it seems to me that there are a few problems here.
• How does rock that is below plasma temperature manage to release electrons? • How do the electrons form electric currents and what maintains the current? • Rock at high temperature has very high resistance. So what forces the current flow? Surely currents should decay rapidly in a high resistance environment. • Convection currents are radial and so will produce magnetic fields which are parallel to the earth’s surface but the observed fields are normal to the earth’s surface at the poles. • Turbulence effects in convection currents will produce irregular magnetic fields at the surface but the earth’s field is mainly regular.
Since the earth’s core is (supposedly) very hot and above the Curie temperature for magnetite it becomes difficult to see how magnetic rock can cause the earth’s field. Unless one supposes that the Curie temperature is higher in rocks under high pressure. Do we have data on the variation of Curie temperature with pressure?
There is another possibility that I would like to suggest: Suppose that the earth’s magnetic field is produced not by convection currents but by a solid core. Suppose that the earth’s core is at a relatively low temperature. The idea that the earth’s centre is hot comes from theories of planetary formation based on accretion. The earth’s lava would form a small concentric layer only a few miles thick. The lava layer would have been created by the Flood when subterranean vaults containing water collapsed. Heat would have been generated by the force of the water escaping through cracks, percussion of the collapsing surface rock layer on the basement, and horizontal centripetal forces arising from the fact that surface rocks rotate the core at a greater speed than those lower down. Hence the sinking surface rocks are subject to a Coriolis effect making them rub horizontally against the basement rocks.
If the foregoing is true then we would expect to see results from seismic surveys suggesting solid rick from a few miles below the earth’s surface to the core. Do we have any such results? —unsigned comment by David Bamber (talk • contribs)