Comments on the Earth's Figure

Abstract

OSMASTON¹ has pointed out that core convection might have important consequences with regard to the Earth's figure and continental drift, and that it is an extremely powerful cause of oblateness. He suggests that observations of J₂ might indicate the amount of change in the magnetic field in the core and therefore the amount of core convection. He seems to be saying that the angular momentum of the Earth can be expressed as where C and ω are the polar moment of inertia and angular velocity and 1, 2, 3 refer to the inner core, outer core and mantle respectively. The mantle and the crust are assumed to be rotating at the same speed; the transfer of angular momentum between solid and fluid parts of the Earth of this kind has also been suggested by Munk and MacDonald².