Implications of the Nonuniform cooling behavior of the eclipsed Moon

Abstract

The lunar surface is characterized by extensive deposits of fragmental debris, providing uniform thermal properties over most of the visible surface. But recent infrared observations during a lunar eclipse have revealed the existence of hundreds of areas whose thermal behavior differs sharply from that of the surrounding terrain. The probable explanation for this behavior is a difference in the insulating properties of the material exposed in these areas. Specifically, a lack of insulating debris over all or parts of the anomalous areas is conceptually sound and explains all the known facts. An analysis of the features and associations of these “hot spots” suggests that the debris is lacking because of simple downslope movement on high angle slopes. The necessity of high angle slopes to promote efficient removal of debris indicates that electrostatic particle transport is not significant on the Moon and debris accumulations must be strongly dominated by local sources. Thus if there are widespread debris deposits of substantial thickness on the Moon, they must be characteristic of lunar continents rather than maria. The lack of debris on high angle slopes also suggests that the debris particles may be essentially noncohesive in the lunar environment. If this is true, the lunar deposits should approximate similar terrestrial deposits in density and strength.