A Method for Quantifying Paleoenvironmental Impacts on Lunar Recession and the Moon’s Age

Abstract Geological evidence indicates that the Moon formed at least 4.46 billion years ago. Models of Earth–Moon evolution generally describe tidal friction as the primary driver of lunar recession—the gradual increase in the lunar orbital semimajor axis—and the corresponding lengthening of Earth’s day. However, tidal dissipation within Earth’s oceans is sensitive to climatic and tectonic boundary conditions, which introduce variability not fully captured in existing models. Here, we develop a probabilistic framework that quantifies lunar recession and its variations by incorporating the influence of climate dynamics, plate tectonics, and geological constraints on Earth’s length-of-day evolution. Applied to the past 1 billion years, the analysis yields an additional, previously unrecognized long-term lunar recession of ∼0.84 mm yr −1 , equivalent to an orbital expansion of ∼808 km. This signal is primarily associated with sea-level change acting on the surface of the Earth with evolving plate configurations, with a particularly strong expression during the Cenozoic Era. The revised recession history adds an uncertainty of ∼15 million years to the lunar age. These findings suggest that slightly lower tidal dissipation rates than those used in earlier models provide better agreement with geological constraints on lunar chronology.