Research indicates the Earth's magnetic field drives contra-rotating solid and liquid cores. Interaction between the two layers is believed to generate the Earth's magnetic field. Somehow that sounds funny, but I guess it must be so. “The magnetic field pushes eastwards on the inner core, causing it to spin faster than the Earth, but it also pushes in the opposite direction in the liquid outer core, which creates a westward motion.” http://www.leeds.ac.uk/news/article...r-old_problem_the_dynamics_of_the_earths_core http://www.pnas.org/content/early/2013/09/13/1307825110 The associated electromagnetic torque currently is westward in the outermost outer core, whereas an equal and opposite torque is applied to the inner core. Decadal changes in the geomagnetic field may cause fluctuations in both these effects, consistent with recent observations of a quasi-oscillatory inner-core rotation rate.