Starship Asterisk*

Convection currents in the outer liquid core could create a magnetic field that would be accentuated by the solid iron core similar to a electrical solenoid with an iron core. The solid iron core rotation could be slowed with respect to the liquid core due to the drag caused by the interaction of the magnetic field in the mantle and the magnetic field in the solid core.

Due the the Earth's rotation the convective currents in the outer core roughly align themselves to create a large dipole magnetic. The field is strong enough to leak through the dielectric mantle and crust to form an external magnetic field that produces the Earth's magnetic shield, auroras, mild electrical currents in the Earth's oceans, and fairly consistent compass readings.

Chris, you know I will always end with a question. Do you think it is plausible that a magnetic disturbance of a near accounter of another magnetic celestial body would interact with the Earth's magnetic field ( when it was possibly several times stronger than present ) to jerk and displace the mantle and crust relative to the liquid and solid core ? The forces required might not be that great since the the liquid interface between the mantle and the solid core act like a lubricated bearing.

3/30/2011

The Code wrote:Why Could the Earth Inner core Be detached from the Crust with regards to spin ?

The inner core is mechanically detached from the mantle and crust by the low viscosity liquid outer core. Given that, why would you necessarily expect the inner core to have the same angular velocity as the mantle? Drag effects might slow it down, or outer core convection might speed it up, and of course there are possibilities of energy transfer via magnetic interactions, as well.

Why Could the Earth Inner core Be detached from the Crust with regards to spin ?

(Quote)
Because the inner core is not rigidly connected to Earth's solid mantle, the possibility that it rotates slightly faster or slower than the rest of Earth has long been entertained.[citation needed] In the 1990s, seismologists made various claims about detecting this kind of super-rotation by observing changes in the characteristics of seismic waves passing through the inner core over several decades, using the aforementioned property that it transmits waves faster in some directions. Estimates of this super-rotation are around one degree of extra rotation per year, although others have concluded it is rotating more slowly than the rest of Earth by a similar amount.

http://en.wikipedia.org/wiki/Inner_core

tc