6.2 In Situ Measurements of Dust

Extract

In this colloquium, my colleagues and I have reported on data from both the lunar surface and from interplanetary space. I am going to comment briefly amd individually on each of these disciplines insofar as they pertain to cosmic dust, but first I would preface those comments with a personal philosophy for each of the two stated disciplines. The two philosophies, you will find, are directly opposite. Concerning the lunar surface, one must recognize that it is a relatively unexplored area for in situ measurements. Accordingly, one must be sufficiently flexible and open-minded to include and consider all available experimental evidence and data until a somewhat consistent model of the lunar surface is derived. Further, and in a similar vein, one’s thinking must not be limited to what little we already know about the lunar surface nor to what is known about the Earth’s surface and terrestrial particles -- assuming that lunar particles are similar to Earth particles. Our lunar experimen shows strong evidence for the electrostatic transport of fines, and yet it is difficult to accommodate that phenomenon on the lunar surface in view of associated parameters that have been derived for the lunar surface, and in terms of what we know about the electrostatic surface properties of terrestrial particulates. But the electrostatic surface properties have been determined in the laboratory on terrestrial particles which are known to have vastly different properties from lunar fines. Thus, it becomes importhat to compile and consider all available data during this early exploration.