Scientists have discovered a crater on the moon that is larger than the Roman Colosseum, resulting from a powerful impact that occurred two years ago and initially went undetected. The crater measures approximately 728 feet across and up to 141 feet deep, making it the solar system’s largest known impact crater formed in recent times. Researchers estimate that such large-scale events occur only once every 132 years, providing valuable information as NASA plans to establish a base for astronauts on the moon.
“This event constitutes a statistically rare, effectively once-in-a-lifetime observation,” the scientists stated in one of two studies published in the journal Science Advances. NASA’s Lunar Reconnaissance Orbiter (LRO) identified the crater on the moon’s near side in May 2024, shortly after it was created by an incoming fragment of an asteroid or comet. The impact went undetected by telescopes on Earth and in space at the time.
The LRO’s wide-angle images were not analyzed until August 2025, and the spacecraft captured more detailed images last fall, confirming the discovery early this year. The crater has been named after the late Thomas McGetchin, a former director of Houston’s Lunar and Planetary Institute, and is three times larger than the previous record-holder identified by the LRO a decade ago.
The moon, which has been pockmarked since ancient times, features some of the solar system’s largest impact craters, including one that spans over 1,500 miles. This latest impact disturbed the lunar surface over an area exceeding 66 miles. Mark Robinson, chief scientist for the LRO’s cameras at Intuitive Machines, noted that dust and rocky soil were ejected at a higher angle than expected. Robinson was the lead author of one of the studies.
A separate study identified a 4-mile-wide cold spot surrounding the new crater, suggesting a loosening of the moon’s topsoil. Co-author David Paige from the University of California, Los Angeles, compared the process to gardening, stating, “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.”
The LRO has made numerous crater discoveries since its launch in 2009, indicating that the moon’s top inch of soil is being overturned by ejected material every 80,000 years, which is faster than previously believed. Robinson commented that contrary to the notion that the Apollo moonwalkers’ footprints will last indefinitely, they will “definitely be long gone in that time frame.” The next step involves assessing the risk of ejected material from craters impacting NASA’s planned moon base, which will assist engineers in reinforcing structures to minimize potential damage.