NASA: McGetchin Crater on the Moon Spans 222 Meters

NASA announced on September 16 and 17 that the Lunar Reconnaissance Orbiter (LRO) had found the largest crater formed in recent times ever recorded in the solar system. The discovery is described in two papers published simultaneously in the journal Science Advances, volume 12, issue 38 (ScienceDaily lists the publication date as September 16). The crater has been officially named McGetchin, after lunar scientist Tom McGetchin, and sits near the eastern edge of the Moon’s near side. It measures 728 feet, about 222 meters, across, and is up to 141 feet, about 43 meters, deep. It formed sometime between April 11 and May 22, 2024, when it was struck by a comet or asteroid roughly the size of a three to six story building. According to NASA, an impact of that scale happens on the Moon once every hundred years or less often.

The crater was not discovered the moment it formed, but a year and a half later. LRO has orbited the Moon for more than 17 years and has identified at least 1,000 new impact craters during its mission, along with about 100,000 additional surface changes, whether from the impact itself or from ejected material. The LROC camera team regularly scans high resolution images for smaller changes, but every few years also produces comparative maps of the entire surface to catch larger ones, wider than 150 feet. Robert Wagner, an image processing specialist at Intuitive Machines and a member of the LROC camera team, was running exactly that kind of comparison on October 24, 2025. He was going through hundreds of older and newer wide angle camera images when he noticed a bright spot with a dark halo around it.

“I just stopped, dropped everything, and started looking into what that spot was,” Wagner said in a NASA statement. The image comparison software typically flags hundreds of false positives for every change in lighting or shadow, so Wagner checks each signal by hand, looking for the faint, blurry halos around bright spots that mark ejected regolith. McGetchin stood out right away, he said. “It was by far the most obvious impact debris pattern I’ve ever seen in one of these images,” he added.

After the discovery, scientists used LRO’s narrow angle camera, which shoots at a resolution of about three feet per pixel, to measure the exact shape and size of the crater and the surrounding terrain. According to NASA, that data will be used to estimate the size and energy of the object that struck the Moon, a calculation expected in a future paper.

Why the ground around the crater is colder

In a second paper, published the same day in the same journal, a team working with the Diviner thermal instrument measured that the ground within about 4 miles, roughly 6.4 kilometers, of the impact site runs about 16 degrees Fahrenheit, roughly 9 degrees Celsius, colder at night than the surrounding terrain. The authors explain that the impact loosened the regolith around the crater, leaving it less dense and less able to hold heat after sunset. The authors of both papers include Mark S. Robinson, Emerson J. Speyerer, Prasun Mahanti, Julie D. Stopar, Benjamin T. Greenhagen, Jean-Pierre Williams and David A. Paige.

The cold spot shows that the impact’s effects reach beyond the crater itself, which, according to NASA, could affect how rover wheels interact with the surface in that area.

The finding does not prove that impacts of this kind are becoming more frequent, nor does it pin down exactly how large the object that struck was, since that estimate is still to come in a future paper. The once every hundred years figure is a statistical estimate drawn from the existing catalog of more than a thousand recorded craters, not a measured fact about this particular event, and the impact date itself is known only as a window between two observations, April 11 and May 22, 2024, not as an exact day.