The Moments of Inertia and the Density Distribution of the Moon

Values of the moment of the Moon's inertia ratios $$A/Mr_{0}\,^{2},\,B/Mr_{0}\,^{2}$$ are calculated from a least squares adjustment of data concerning the gravitational potential and the physical librations. The best values are $$C/Mr_{0}\,^{2}\,=\,0\cdot3950$$ , $ $A/Mr_{0}\,^{2},\,B/Mr_{0}\,^{2}\,=\,0\cdot3948$$ all with a standard deviation of 0 ·003. The sources of uncertainty of the data are discussed and the importance of new types of observation of the librations is emphasized. The bearing of the results upon the distribution of density in the Moon is considered.