The moon’s surface experienced a violent encounter with a comet or an asteroid — and has a massive battle scar to prove it. The space rock, estimated to be the size of building reaching between three and six stories, slammed into the moon’s eastern edge two years ago, between April 11 and May 22, 2024, although researchers didn’t notice it at the time. The impact left behind a crater measuring 728 feet (222 metres) wide, or just over the length of two football fields. Spotted last year, the crater also reaches 141 feet (43 metres) deep — room for three school buses stacked atop one another. Scientists said the lunar feature marks the largest newly formed crater ever found in the solar system since humans have monitored such features, according to a study published Wednesday in the journal Science Advances. “Crater production models indicate that an impact of this magnitude is expected to occur only once every 132 years on the Moon,” the authors wrote in the study. “As such, this event constitutes a statistically rare, effectively once-in-a-lifetime observation.” The study authors named the feature McGetchin crater in honor of Dr. Thomas McGetchin, the late Apollo-era lunar scientist who contributed to a greater understanding of impact cratering on the moon. Before this discovery, the largest contemporary impact crater found on the moon was an estimated 230 feet (70 metres) in diametre. Unlike Earth, the moon’s surface is heavily cratered with no protective atmosphere to shield it from the bombardment of space rocks over billions of years. Spotting a new crater among the multitude of existing features seems a bit like finding a needle in a haystack, but a NASA orbiter that has been circling the moon for more than 17 years helped scientists zero in on the large bright spot encircled by a dark halo. Scientists have used data from the Lunar Reconnaissance Orbiter to study the impact of the crater and just how much the collision disrupted the surrounding area. The insights reveal that the moon — a high-priority destination for NASA and other space agencies when considering sustained human exploration — is still a hub of impact activity that needs monitoring as it could be a threat to any potential people and infrastructure on the surface. “I am surprised almost every day when I come into work and look at the latest images from the Moon — even after 17 years of operation,” wrote study coauthor Mark Robinson, principal investigator for the Lunar Reconnaissance Orbiter Camera at Texas-based aerospace company Intuitive Machines, in an email. Keeping an eye on the moon The Lunar Reconnaissance Orbiter, or LRO, has been a workhorse since launching in 2009, using seven instruments to create maps of the moon’s temperature, surface composition, topography and radiation. It moves in a loop from pole to pole, with two cameras to capture imagery 60 miles (97 kilometres) from the lunar surface. As a result, the spacecraft has also enabled scientists to track at least 1,000 new impact craters and 100,000 other surface changes, including landslides and even landers that crash into the lunar surface. Tiny space rocks too small to see create many of the moon’s pockmarks and craters. About 140 new craters that appear on the moon each year — some of which can span about 30 feet (9 metres) across — are the work of space rocks measuring about 43 inches (109 centimetres) wide. But every few years as scientists scan detailed LRO images, they look for larger features by comparing new lunar maps with older versions. Study coauthor Robert Wagner, image-processing specialist at Intuitive Machines who works with Lunar Reconnaissance Orbiter Camera data, spotted McGetchin on Oct. 24, 2025, while looking at stacked before and after LRO images that highlight unusually dark or bright surface changes. “I just stopped, dropped everything, and started looking into what that spot was,” Wagner said in a statement. The process is not an easy one, given that the software LRO scientists use flags every shift connected with lighting or shadows. The team looks at every detection and evaluates whether it’s real, or a false positive, Robinson said. But McGetchin stood out to Wagner. “It was by far the most obvious impact debris pattern I’ve ever seen in one of these images,” he said. To confirm the discovery, the team turned to sharp, close-up images captured by the orbiter’s Narrow-Angle Camera, which also enabled researchers to measure the crater’s shape, size and impact to the surrounding terrain. A separate team of scientists analyzed data from LRO’s Diviner thermal instrument, which revealed an area spanning four miles (6.4 kilometres) wide surrounding the crater that registers 16 degrees Fahrenheit cooler at night compared with the rest of the region. They shared their results in a second paper published Wednesday in Science Advances. “Previous Diviner observations have shown that fresh lunar impact craters are often associated with ‘cold spots,’” wrote lead study author Tyler Powell, planetary scientist and postdoctoral fellow at the Johns Hopkins University’s Applied Physics Laboratory, in an email. “Their large extent indicates that impacts can modify the surface far beyond the crater itself,” Powell said. “We’re extremely lucky it formed during the lifetime of the LRO mission and that we are able to observe the region both before and after impact.” Scientists believe the cold spots occur due to disturbances in the lunar surface, “creating a fluffier layer that is less able to retain heat throughout the night,” Powell added. What craters can reveal Tracking lunar surface changes is crucial for determining just how often space rocks slam into the moon and how asteroids break apart as they strike a rocky body, Robinson said. Studying new craters can also provide insights into what happens during the moment of impact, he said. Understanding the rate and magnitude of such impacts on the moon could be critical for future planning of a moon base and other infrastructure as NASA’a Artemis program works toward returning humans to the lunar surface for long-term exploration. Impact craters have also helped shape the surfaces of the rocky planets and moons across our solar system, said Jeff Andrews-Hanna, a professor in the Lunar and Planetary Laboratory at the University of Arizona. Andrews-Hanna was not involved with either study. “An impact like that should be rare on the Moon, but rare events do happen. The object that made this crater may have been close in size to the Chelyabinsk meteor that exploded over Russia,” Andrews-Hanna wrote in an email, referring to an asteroid that entered Earth’s atmosphere over Chelyabinsk, Russia, in 2013. About 55 to 65 feet (17 to 20 metres) in size, the Chelyabinsk asteroid exploded in the air, releasing 20 to 30 times more energy than that of the atomic bomb dropped on Hiroshima, Japan, and generating brightness greater than the sun. Debris from the space rock damaged more than 7,000 buildings and injured more than 1,000 people. “If something like that made it through our atmosphere and struck the surface of the Earth, it wouldn’t be catastrophic, but we would certainly take notice,” Andrews-Hanna said. “These events serve to remind us of how vulnerable we are, and how important it is to catalog and track near-Earth asteroids that could potentially hit the Earth.”
