Geomagnetic Mysteries

How interesting – we seem to have a paradoxical core inside the Earth. It is the core that is supposed to form the geomagnetic by the flow of heat through the liquid outer core helps slosh the molten iron generating a magnetic field. Except that more recent deliberations considered the possibility that the core conducts heat more readily than previously thought, resulting in less mixing in the outer core and a younger earth with a weak magnetic field, if any at all. This is contradicted by palaeomagnetic data showing a powerful geomagnetic field billions of years ago. (source).

Whoopsies. We have a paradox. The paradox lies entirely in the virtual world of super-computing and the modelling of the geomagnetic field via the geophysical ‘dynamo’ theory. This theory is based on an assumed rotational differential between the solid inner core and the liquid outer core and the (mis)application of the Coriolis effect. The field is complex because it appears to have 2 dipole structures and is also slowly drifting westwards. And the field also has a diurnal component of a 24 hour period.

The main driving force of the dynamo model is ancient heat fueled by left-over energy by cosmic collisions that slowly conducted outwards through the liquid outerlayers that surround the solid inner core ultimately providing convection that swirls the molten iron in the outer core and that behaves as a dynamo which, if operating in an existing magnetic field, here the solar magnetic field, induces an electric current that strengthens the pre-existing weka field. If heat flow increases by conduction rather than convection then the induced field becomes weaker and so too the geomagnetic field.

I suspect there is a lot of circular reasoning at work here, apart from the adoption of some brave assumptions based on biblical, or if one is a secular humanist, secular creationism. You know, the problem of starting with nothing and then figuring out what happened next; especially difficult if you don’t understand the process of thinking in the first place, since it as this process of thinking that created the paradox in the first place.

What amuses me is a comment attributed to a geophyscist at the Carnegie Institution for Science in Washington, D.C., where he admits that “rising and falling conductivity predictions may seem like scientists running in circles”.

Not only running but also thinking in circles.

Mind you, when this dynamo model was first mooted in the early 20th century, we assumed a clock-work like universe where planets and suns behaved like billiard balls suspended in a vacuum obeying Newton’s Laws of motion. We did not know of the solar wind or plasma and Kristiaan Birkeland’s work with auroras was studiously ignored. So it is fair enough that the model was limited to what we knew scientifically at the time. But today is 2015 and we now know that the conductive earth is surrounded by a co-rotating torus of electrical charge known as the Van Allen Belts; so guess what might be producing the geomagnetic field – the known Van Allen belts, or the mysterious, paradoxical, invisible process inside the Earth only known to the geomathematicians and their computerised simulations?

About Louis Hissink

Retired diamond exploration geologist. I spent my professional life looking for mineral deposits, found some, and also located a number of kimberlites in NSW and Western Australia. Exploration geology is the closest one can get to practicing the scientific method, mineral exploration always being concerned with finding anomalous geophysical or geochemical data, framing a model and explanation for the anomaly and then testing it with drilling or excavation. All scientific theories are ultimately false since they invariably involved explaining something with incomplete extant knowledge. Since no one is omniscient or knows everything, so too scientific theories which are solely limited to existing knowledge. Because the future always yields new data, scientific theories must change to be compatible with the new data. Thus a true scientist is never in love with any particular theory, always knowing that when the facts change, so too must he/she change their minds.
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