THE INSTABILITY OF A FLUID SPHERE HEATED WITHIN

Abstract

At a certain stage in the cooling of the Earth a type of circulation could arise, analogous to the cellular convection of H. Bènard. G. F. S. Hills has suggested this as an explanation of the distribution of continents. It is found that the easiest modes to excite are those in which the disturbances of temperature and radial velocity contain spherical harmonics of degree I, and the surface currents would tend to sweep floating matter to one side. The theory shows some prospect of providing an explanation of the land and water hemispheres, though there are some outstanding difficulties. An approximate solution is also derived for a spherical mass with a rigid boundary, heated from within. It is again found that the easiest modes to excite correspond to harmonics of degree I.