Possible Convection in the Lunar Interior

Abstract

In the preceding chapter of this book we have given an outline of the phenomena to be expected in the Moon’s interior if its material behaves as an elastic solid. The physical reasons why the Moon should behave so at least in the outer parts of its interior are indeed overwhelming; but is this necessarily the case also in the deep interior of our satellite? The relatively high temperatures which we have reasons to expect there as a result of radiogenic heating, as discussed in Chapter 8, entail a number of interesting consequences; and one should be at least a partial melting of rocks exposed to them for a sufficiently long time. The problem of the occurrence of melting at pressures encountered in the lunar interior has, in recent years, been discussed in particular by Urey (1962a); and indications of the temperatures at which the melting of the silicate rocks should commence (or become complete) under these conditions have been given by him. if so, however, it is reasonable to inquire as to whether such material would be susceptible of actual hydrodynamical flow over time intervals comparable with the age of the Moon; but before attempting to answer this question, let us inquire first about a possible cause of such a motion.