Planetary reorientation by surface loads

Abstract

Non-hydrostatic concentrations of mass at the surface of the planet have been suggested as mechanisms of permanent reorientation for all of the terrestrial planets and for the Moon. In order for such a load to control planetary orientation, three conditions must be satisfied. The surface load must be non-hydrostatically supported; the surface load must be large compared to internal departures from a hydrostatic mass distribution; and the load must be large compared to hydrostatic departures of the planetary figure from a sphere. The third condition comes from the consideration that if the load is non-hydrostatically supported, then the same processes which support the load will also the hydrostatic figure.