Death of the Dynamo
(For purposes of this article the note ‘conducting metallic hydrogen’ should read ‘Swirling Liquid Iron’)
“As if the inside story of our planet weren’t already the ultimate potboiler, a host of new findings has just turned the heat up past Stygian.” This the opening line of a NY Times Science article concerning new data on the Earth’s core. Far be it for any establishment science to criticize the ‘Standard Model’, but the work published by a consortium of British (Dario Alfe of Uni. College of London) and American scientists comes very close.
Their paper in the journal Nature claims that the measured heat conduction from the core of the Earth is two to three times greater than previously estimated. This is important because the alternate method of heat transport, convection, the swirling of liquid iron in the outer core, is necessary to drive the ‘Dynamo Effect’ – currently believed to generate the magnetic field of the Earth. If the conduction is as strong as reported, there is insufficient heat to drive the ‘dynamo’. This dilemma has quickly spurred the suggestion of a numbet of highly unlikely mechanisms which might supply additional heat, such as unrecognized stores of radioactive potassium or thorium, or a faster crystallization of the solid core, in an effort to ‘save the dynamo’.
Another difficult aspect of the dynamo effect is its requirement for a very low viscosity of the liquid iron which comprises the outer core – counter to real Earth (RE) measurements which indicate it is much higher. Additional evidence counter to the ‘dynamo’ model is present in a number of recorded sudden global changes in the second time derivative of the Earth’s magnetic field. If, as pictured, the dynamo effect is the result of a number of independent gyres, each of which takes hundreds or even thousands of years for a single circulation, it would be impossible for the entire magnetic field of the Earth to suddenly change.
It has long been known that the solid core is not dense enough to be pure iron. Many geophysicists believe that it contains significant siderophile (iron loving) elements such as sulfur and oxygen, but because of their relatively high atomic weights, quite a large amount of these elements would have to be present to attain the measured density. Some geophysicists have recently recognized a study of iron in a diamond anvil at 35,000 atmospheres in which the mere presence of hydrogen produced an expansion of the sample by 17%, thereby reducing its density. (Badding, Hemley and Mao, “High Pressure Chemistry of Hydrogen in Metals, Science, 26 July 1991, p.421). This amazing discovery was the result of a rapid and reversible chemical reaction resulting in an entirely new crystal with alternating layers of hydrogen and iron atoms, which they designated FeH. A few geophysicists (Okuchi, Hirao) have since studied FeH, but what no one has picked up on, is the cited authors’ suggestion that the crystal structure resembles that of some known superconductors. This led me to propose, some fifteen years ago, that the geomagnetic field originates in supercurrents flowing in the solid iron core, and is ‘pumped up’ by waves of charged particles from the Sun (CMEs) which spiral into the geomagnetic poles, by Faraday’ and Lenz laws.
Several additional factors are consistent with this hypothesis. Based on seismic studies, Miaki Ishii and her colleagues at Harvard have proposed that nested within the solid inner core there exists another distinct layer they call the ‘innermost core’ – a structure some 375 miles in diameter. This layer could mark the presence of the FeH superconducting layer. In this system, the ponderous rotating gyres of liquid iron in the outer core, which carry no electrical charge, would merely be the cause of the slow variations in the geomagnetic field, which otherwise might be close to a perfect dipole field.
Lastly, in the Cyclic Catastrophism scenario, Mercury was the former solid core of Mars, which exited the planet only 2,700 years BP. The ‘planet’ Mars has many magnetic rocks on its surface, but no longer has a global magnetic field or even a solid core. On the other hand, the solid iron ‘planet’ Mercury still has a global dipole magnetic field. It is much weaker now because FeH forms only under very high pressure and therefore has sunk to considerable depths within Mercury. The magnetic field of Mercury has prompted diehard ‘dynamo’ advocates to claim that it has a liquid ‘outer core’. Lets just allow the ‘dynamo’ to die a natural death.