AI Insight
A new study uses numerical simulations and observational data to analyze how small lunar craters (50-500 meters in diameter) degrade over time, finding that degradation rates depend strongly on crater size and whether they are located in maria or highland regions. The research reveals that small craters under 100 meters in diameter have relatively short lifetimes of less than 100 million years. These improved degradation rate estimates provide better constraints for determining the age of lunar surface units based on crater populations.
Why it matters
This research improves the accuracy of using craters to date lunar surfaces and has implications for understanding lunar water preservation. Since small craters degrade within 100 million years, any water ice currently found in them must be of recent origin, helping scientists determine whether lunar water comes from recent impacts or ongoing solar wind processes.
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: AGU Advances
Lunar impact craters are widely used to determine the ages of surface units and can also serve as cold traps that preserve water ice. However, craters degrade over time, and understanding the factors that control degradation rates is essential for accurate age determination.
Zhang et al. [2026] investigates the morphology of small lunar craters (50-500 meters diameter) through numerical simulations of crater formation and evolution, combined with comparisons to observed crater dimensions. Crater degradation depends strongly on both crater size and local topography; maria versus highlands. This study estimates the variations in degradation rate, resulting in substantially improved constraints on crater retention ages. Because craters can trap water delivered either by impacts or through the gradual accumulation of solar-wind-derived hydrogen, understanding their lifetimes also has important implications for the origin and preservation of lunar water. Small craters (<100 meters diameter) have relatively short lifetimes (<100 million years); therefore, any water currently preserved within these features is likely of recent origin.
Citation: Zhang, M., Fa, W., Tong, J., & Liu, Y. (2026). Degradation rate and lifetime of small impact craters on the Moon. AGU Advances, 7, e2026AV002542. https://doi.org/10.1029/2026AV002542
—Vincent Salters, Editor, AGU Advances
Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.
Source: Disappearing Moon Craters