Brief
Moon’s Radius Shrinks by About 148 Feet Over Hundreds of Millions of Years, Study Finds
Analysis of LROC images shows the Moon is contracting at a glacial pace, creating faults that could affect future lunar missions.
By Felo News Desk · Published
Scientists led by Smithsonian planetary geologist Thomas Watters report that the Moon’s overall radius has decreased by nearly 148 feet over the past 400–800 million years as it continues to cool.
What happened
Using more than 17 years of imagery from NASA’s Lunar Reconnaissance Orbiter Camera, the team identified over 10,000 young lunar faults. Their calculations translate to a shrinkage rate of about 2.4–4.3 inches per million years, or roughly 0.1 micrometer per year.
What the reports add
The study, published in The Planetary Science Journal, notes that unlike Earth’s multiple tectonic plates, the Moon is encased in a single shell‑like plate, allowing cooling‑induced slips anywhere on its surface.
What was said
“The number of these young faults revealed in LROC images is much greater than I ever imagined,” Watters told Popular Science.
How it came about
The findings build on decades of lunar mapping and may help NASA plan for long‑term human presence on the Moon by better understanding moonquake distribution.
Key facts
- The Moon’s radius has shrunk by about 148 feet over 400–800 million years. (popsci.com)
- The shrinkage rate is roughly 2.4–4.3 inches per million years (0.1 micrometer annually). (popsci.com)
- Researchers identified more than 10,000 visible lunar faults using LROC data. (popsci.com)
- Thomas Watters leads the study published in The Planetary Science Journal. (popsci.com)
Sources
- [1] popsci.com — originally reported as “The moon is shrinking. Astronomers finally know how fast.”
