The moon is shrinking as it continues to cool off.
Lobate scarfs, cliffs in the lunar crust, indicate the moon shrank globally in the geologically recent past and might still be shrinking today, according to a team analyzing images from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft.
The moon formed in a chaotic environment of intense bombardment by asteroids and meteors. These collisions, along with the decay of radioactive elements, made the moon hot.
The moon cooled off as it aged, and scientists have long thought the moon shrank over time as it cooled, especially in its early history. The new research reveals relatively recent tectonic activity connected to the long-lived cooling and associated contraction of the lunar interior.
Dr. Thomas Watters of the Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum, Washington estimates the distance between the moon's center and its surface shrank by about 300 feet in recent geological time (100 million to 1 billion years).