DI024-0003
The Moon as a cornerstone of understanding for terrestrial planetary interiors

Tuesday, 15 December 2020
Poster
Renee C Weber, NASA Marshall Space Flight Center, Huntsville, AL, United States, Clive Robert Neal, University of Notre Dame, Notre Dame, IN, United States, Nicholas C Schmerr, University of Maryland College Park, College Park, MD, United States, Heidi Haviland, NASA Marshall Space Flight Center, Heliophysics and Planetary Science Branch, Huntsville, AL, United States and Barbara A Cohen, NASA Goddard Space Flight Center, Greenbelt, MD, United States
Abstract:
The Moon retains a compositional and temporal record of its formation and evolution. Its internal heat engine waned early in its evolution, thereby preserving the initial differentiation event – information that has been lost on Earth due to crustal recycling and mantle overturn. The Moon therefore serves as a cornerstone within our Solar System for understanding the initial evolution of all terrestrial planets. The Apollo missions revolutionized our understanding of the Moon, but new geophysical data are needed to address the many questions that remain:

1. How do terrestrial planets differentiate? Imaging the Moon’s interior provides a window into early formation processes and how planets evolve from an initial magma ocean. The Moon retains remnants of magma ocean crystallization, which took place in the early histories of all terrestrial planets. Studying the Moon’s crust, mantle, lower mantle/core, and lateral variations will reveal if an overturn event occurred in the mantle, and if the crustal PKT layer is linked with the formation of a partial melt layer at the CMB.

2. What processes shape planetary surfaces, and how do surfaces record Solar System history? Stagnant lid conduction is assumed for smaller bodies, as is global contraction. The thermal evolution of terrestrial objects is tied to their tectonic evolution. Seismicity measurements determine whether a planet has been geologically inactive since reaching the stagnant lid regime. The rate of heat loss is determined by internal dynamics. Heat flow measurements determine whether a planet is a simple conductive cooling system, or more complex. Early crustal evolution and the role of giant impacts can serve as a model for seeding the fracture density needed to initiate plate recycling on larger bodies.

3. How do worlds become habitable, and how is habitability sustained? The core dynamo is important for magnetic field generation, which is relevant for long-lived habitability. The strength and duration of the lunar dynamo can be determined by improved seismological imaging of the Moon’s core structure. The volatile history of the Earth-Moon system is preserved on the Moon; magnetotelluric sounding and to a lesser extent seismology can address if the lunar interior is dry and degassed, or volatile enriched.

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