Summary
NASA’s Lunar Reconnaissance Orbiter has identified McGetchin, a 728-foot-wide crater formed on the Moon between April 11 and May 22, 2024. The impact also disturbed the surrounding surface, creating a four-mile-wide region that is significantly colder at night.
NASA’s Lunar Reconnaissance Orbiter (LRO) has identified a new Moon crater formed during a rare impact between April 11 and May 22, 2024. Named McGetchin after lunar scientist Tom McGetchin, the crater is 728 feet wide and 141 feet deep.
NASA says researchers reported McGetchin as the largest newly formed crater yet found in the solar system. The impact is estimated to occur on the Moon about once a century or less frequently. The object that struck the surface was probably a comet or asteroid roughly the size of a three- to six-story building.
How the crater was discovered
The discovery began during a routine check of lunar mapping data on Oct. 24, 2025. Robert Wagner, an image-processing specialist working with the Lunar Reconnaissance Orbiter Camera (LROC), compared hundreds of images taken at different times and used software to highlight changes. Areas that remained the same appeared gray, while changed regions appeared bright or dark.
The initial images came from LROC’s Wide-Angle Camera, which captures broad views with pixels roughly the size of American football fields. McGetchin stood out because the impact had scattered bright debris across a large area, producing a visible pattern around the new crater.
Scientists then used LROC’s sharper Narrow-Angle Camera to examine the site. That instrument captures images at about 3 feet per pixel, allowing the team to determine the crater’s size, shape, and effects on the surrounding terrain. LRO observations also placed the impact site on the Moon’s eastern edge.
LRO has orbited the Moon for more than 17 years with seven instruments that map its topography, surface composition, temperature, and radiation environment. During the mission, the spacecraft team has identified at least 1,000 new impact craters and flagged about 100,000 other surface changes associated with impacts and ejecta—the material thrown outward during a collision.
The impact changed more than the crater itself
Follow-up observations from LRO’s Diviner thermal instrument found a cold region about four miles across around McGetchin. At night, this area was about 16 degrees Fahrenheit cooler than nearby terrain.
The researchers attribute the temperature difference to the impact’s effect on the lunar regolith, the loose layer of dust and broken rock covering the Moon. The collision fluffed up this material, making it less dense and therefore less able to retain heat after sunset.
That finding shows that an impact can alter the lunar surface well beyond the visible crater. NASA notes that such changes could affect how rover wheels interact with the ground—an important consideration as robotic and commercial activity expands on the Moon.
The result also illustrates why repeated orbital imaging is valuable. LROC scientists usually inspect detailed images for changes smaller than 30 feet, while periodic comparisons of global maps help reveal features wider than 150 feet. Combining before-and-after images with thermal measurements allows researchers to study both the crater and the broader physical disturbance produced by the impact.
NASA’s account places the formation within a date window rather than assigning a single impact time. It describes the impactor as a comet or asteroid possibly three to six stories tall; further estimates of the object’s size and impact force are expected in a future paper.