Between April 11 and May 22, 2024, an asteroid or comet fragment the size of a three- to six-story building impacted the near side of the moon, carving out a 728-foot-wide and 141-foot-deep crater that is larger than the Roman Colosseum and represents the largest newly formed impact crater discovered in the solar system.
When NASA’s Lunar Reconnaissance Orbiter (LRO) team ran routine quality checks on lunar mapping data, they spotted a bright spot ringed by a dark halo. That anomaly revealed a massive, steep-sided scar that completely bypassed real-time detection by Earth and space telescopes when it occurred in the spring of 2024. LRO wide-angle images captured the aftermath, but the data remained unidentified in a massive crush of information until August 2025. Follow-up high-resolution pictures gathered last fall and subsequent analysis confirmed the discovery, culminating in two published studies in the journal Science Advances.
Engineering the Thomas McGetchin Crater Discovery
Named in honor of the late Thomas McGetchin—a former director of Houston’s Lunar and Planetary Institute—the crater measures roughly 222 meters across. This scale makes it three times larger than the previous record-holder discovered by the LRO a decade ago. According to Mark Robinson, chief scientist for the LRO’s cameras at Intuitive Machines and lead author of one of the studies, the impact churned the lunar surface across a span of more than 66 miles. Dust and rocky soil were hurled outward at a higher angle than expected.
Statistically, an impact event of this magnitude occurs only once every 132 years. NASA currently prepares to build a base for astronauts on the lunar surface, making surface stability a primary architectural concern.
Gardening the Regolith and Protecting Future Lunar Infrastructure
A separate study led by David Paige of the University of California, Los Angeles, identified a 4-mile-wide cold spot surrounding the fresh impact site. This thermal signature matches a significant loosening of the moon’s topsoil layer.
“We’re now thinking of impacts as a way to garden the regolith — churning the sediments and putting stuff above that’s usually below the surface,” Paige said.
This natural tilling process happens faster than previously thought. LRO crater observation data indicates that the top inch of the lunar regolith is entirely overturned by ejected material every 80,000 years. Robinson noted that this rapid geological recycling means historic artifacts like the Apollo moonwalkers’ dusty lunar footprints will “definitely be long gone in that time frame.”
By calculating the risk of ejected crater material striking NASA’s planned moon base, researchers can model the hazard posed to planned lunar base installations. Robinson explained that this information will enable structural engineers to harden structures so one won’t have to worry about damage, or maybe worry less.
