Summary
The Moon's age is estimated to be around 4.35 billion years, based on tidally driven remelting, which resolves existing lunar chronological paradoxes and provides information on tidal dissipation in the Earth.
Highlights
- Tidally driven remelting around 4.35 billion years ago indicates the Moon is old.
- The Moon's age is estimated based on the remelting event, not the original crystallization of the lunar magma ocean.
- The remelting event was caused by the Moon's orbital evolution, specifically the Laplace plane transition.
- The event resulted in the resetting of the formation ages of most lunar samples.
- The Moon's fossil bulge, absence of ancient impact basins, and disparate late accretionary histories of Earth and the Moon are consistent with a tidally induced remelting event.
- The Moon's early orbital evolution is constrained by the time of the Laplace plane transition.
- The Moon's formation is likely to have occurred between 4.43 and 4.53 billion years ago.
Key Insights
- The Moon's age has been reevaluated based on tidally driven remelting, which resolves existing paradoxes in lunar chronology. This new understanding provides insights into the Moon's early evolution and the tidal interactions between the Earth and the Moon.
- The remelting event, caused by the Laplace plane transition, resulted in the resetting of the formation ages of most lunar samples. This event has significant implications for our understanding of the Moon's early history and the formation of the Earth-Moon system.
- The Moon's fossil bulge, which is thought to have formed when the Moon was still in a highly eccentric orbit, is consistent with a tidally induced remelting event. This suggests that the Moon's shape was frozen in place before the remelting event.
- The absence of ancient impact basins on the Moon is also consistent with a tidally induced remelting event. This event would have erased any pre-existing basins, resulting in the Moon's relatively young and cratered surface.
- The disparate late accretionary histories of Earth and the Moon can be explained by a tidally induced remelting event. This event would have resulted in the Moon's mantle being depleted in highly siderophile elements, which are abundant in the Earth's mantle.
- The Moon's early orbital evolution is constrained by the time of the Laplace plane transition. This transition, which occurred around 4.35 billion years ago, marks a significant event in the Moon's early history and provides insights into the tidal interactions between the Earth and the Moon.
- The Moon's formation is likely to have occurred between 4.43 and 4.53 billion years ago, based on the reevaluation of the Moon's age and the constraints provided by the Laplace plane transition. This new understanding of the Moon's formation has significant implications for our understanding of the early Solar System.
Mindmap
Citation
Nimmo, F., Kleine, T., & Morbidelli, A. (2024). Tidally driven remelting around 4.35 billion years ago indicates the Moon is old. In Nature (Vol. 636, Issue 8043, pp. 598–602). Springer Science and Business Media LLC. https://doi.org/10.1038/s41586-024-08231-0