Effects of instability of the Earth and celestial coordinate systems on Earth orientation parameters

Unknown secular and long-term changes in the Earth orientation parameters attributed to instability (possible rotation) of both the Earth and celestial coordinate systems (ECS and CCS) are studied. Rotation of the CCS due to changes in the coordinates of extragalactic sources resulting from gravitational lensing can lead to errors of the order of several microarcseconds in the orientation parameters. The rotation of the ECS due to the crust pressing on the mantle diminishes the tidal retardation of the Earth's rotation and produces long-term variations in the duration of the day (with a period of about 1500 years) and in the motion of the pole relative to the Earth's surface.     

Analysis of Lunar Terrain Altitudes and Correlation Links between the Terrain and Gravitational Field; Preliminary Conclusions on the Global Density Inhomogeneities of the Lunar Crust

The harmonic and statistical analysis of lunar terrain altitudes has been performed based on the procedure developed by the authors. The explanations for the displacements of the Moon's figure relative to the center of mass and for the shift of the major equatorial axis relative to the earthward direction have been given. The maps have been plotted for the density anomalies in the near-surface layers of the Moon that correspond to mascons (with negative correlation between the field and terrain mainly for N= 10, 11) and other variants of links between the gravitational field and terrain (with positive correlation between the field and terrain). It has been shown that the harmonics of the degree N= 5–9 mainly correspond to the isostatic compensation of the terrain in the near-surface layers of the crust; the low harmonics (N< 5) correspond to the isostatic compensation of the terrain in the deeper layers, while the harmonics of the degrees N > 11 may indicate the presence of tension in the crust generated by small structures of the terrain. Based on the maps, possible locations of deposits of volatile elements (mainly on the far side of the Moon and in the northern cir-cumpolar region) and other natural resources have been determined.

     

Determination of Global Density Inhomogeneities and Stresses Inside the Moon

Solar System Research - The possible distribution of density and stress anomalies in the interior of the Moon is determined. For this purpose, we have developed a new solution of the incorrect...