Scientists have made a significant discovery on the moon, finding a crater larger than the Roman Colosseum resulting from a powerful impact two years ago that initially went unnoticed. The steep-sided crater measures 222 meters across and up to 43 meters deep, making it the largest known recent impact crater in the solar system.
Researchers estimate that such a large-scale event occurs approximately once every 132 years, making this discovery a valuable source of information as NASA plans to establish a base for astronauts on the moon. The scientists highlighted the rarity of this event, describing it as a unique observation that happens effectively once in a lifetime.
The crater was identified by NASA’s Lunar Reconnaissance Orbiter (LRO) on the moon’s near side in May 2024, shortly after it was formed by an incoming fragment from an asteroid or comet. The impact went undetected in real-time by telescopes on Earth and in space. Detailed images of the crater were captured by the LRO last fall, with confirmation of the discovery made earlier this year.
Named after the late Thomas McGetchin, a former director of Houston’s Lunar and Planetary Institute, the crater has churned the lunar surface for over 100 kilometers. The resulting dust and rocky soil were ejected at a higher angle than expected, according to Mark Robinson, the chief scientist for the LRO’s cameras at Intuitive Machines.
A separate study revealed a seven-kilometer-wide cold spot around the new crater, indicating a loosening of the moon’s topsoil. Co-author David Paige from the University of California, Los Angeles, likened the impact to gardening, suggesting that impacts serve to mix the sediments and bring subsurface materials to the surface.
Data from the LRO indicates that the moon’s top two centimeters of soil are overturned by ejected material every 80,000 years, a faster rate than previously believed. Robinson dispelled the myth that the Apollo moonwalkers’ footprints would endure forever, stating that they would disappear within that timeframe.
The next phase involves assessing the risk of ejected crater material hitting NASA’s planned moon base to ensure the structures are resilient and less vulnerable to potential damage.