Thermal Evolution and Tidal Deformation of the Moon

• Applicants: Professor Dr. Jürgen Oberst; Dr. Ana-Catalina Plesa
• Subject Area: Geophysics ; Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 551620924

Models of the interior structure, as well as measurements of the rotation and the deformation of the moon by tidal forces provide important information on the formation of the Earth's satellite and thus also on the formation and evolution of the Earth-Moon system. Due to its proximity to Earth, the Moon became an important target for early exploration by astronauts and robotic missions, and has recently come back into focus as a mission target for international space agencies. The Apollo seismometers, which operated between 1972 and 1977, provided the first models of the Moon's internal structure. Recent missions, equipped with modern "radio science" experiments and laser altimeters, have provided precise data on the gravitational field and tidal deformation. In this project we create global thermo-chemical 3D models of the Moon and derive predictions for the rheology and the deformation of the Moon. The later can be compared to observations of the lunar tidal interaction with the Earth and the Sun. The amplitudes and phases of this periodic deformation provide valuable information about the thermal state and internal structure of the Moon. The goal of the project is to use the measured tidal deformation to determine the thermal evolution and the current thermal state as well as the internal structure of the Moon. To this end, we model the formation and evolution of thermal and chemical anomalies over the entire thermochemical history of the Moon and calculate the present-day tidal deformation. The models that can reproduce the observed tidal deformation are considered successful scenarios and are used to infer the thermal evolution and current state of the lunar interior. In addition to tidal deformation, our global 3D models provide predictions of global contraction and resulting thermo-elastic stresses, as well as seismicity and heat flow that can be compared to observations. For the first time, such a coupled system of geodynamic evolution and tidal deformation is applied to study the thermochemical history and interior of the Moon. Our work will make a significant contribution to understanding the interior structure of the Earth's satellite and will help to formulate requirements for future experiments that may allow further differentiation between different models of the formation and thermal evolution of the Moon.

• DFG Programme: Research Grants