Photo by NASA Hubble Space Telescope on Unsplash
NASA has confirmed the discovery of the largest newly formed impact crater ever found anywhere in the solar system, a massive scar on the lunar surface now officially named McGetchin.
The crater measures 728 feet wide, or about 222 meters, and plunges 141 feet deep, roughly 43 meters, NASA said. It formed sometime between April 11 and May 22, 2024, when a comet or asteroid slammed into the Moon’s surface. NASA scientists pinpointed that narrow window by comparing satellite imagery taken before and after the strike.
A Rare Cosmic Event
Impacts capable of carving out a crater this large are exceptionally uncommon. Scientists estimate that an event of this magnitude happens on the Moon about once in a century or even longer, according to a NASA blog post. The object responsible for the crater is believed to have been roughly the size of a building three to six stories high, researchers said.
The Moon’s lack of atmosphere is central to why such impacts happen at all, and why they leave such dramatic marks. Unlike Earth, the Moon has virtually no atmosphere, so incoming space debris never slows down or burns up before slamming into the ground, researchers explained. On Earth, most objects of similar size would disintegrate in the atmosphere long before reaching the surface. On the Moon, there is nothing to stop them.
Despite how rare an impact of this scale is, smaller collisions happen constantly. Scientists estimate that impacts of this general scale produce about 140 new craters across the Moon each year, NASA said, though most are far too small to be identified in orbital images. McGetchin stands out precisely because its size makes it impossible to miss once spotted.
How the Discovery Was Made
The crater was discovered by Robert Wagner, an image-processing specialist working on the camera team for NASA’s Lunar Reconnaissance Orbiter, during what began as a routine data-quality check, according to reporting on the discovery. The orbiter has been studying the Moon continuously since 2009, building an enormous archive of images that scientists use to track changes on the lunar surface over time.
Wagner noticed something unusual: a large bright spot circled by a dark halo, a telltale visual signature of a fresh impact, according to a researcher account of the discovery. By comparing before-and-after images of the Moon, Wagner realized he had stumbled onto the largest newly formed crater ever found in the solar system, NASA said, a finding scientists later detailed in the journal Science Advances.
Around the crater, researchers also identified a striking thermal anomaly. A roughly 4-mile-wide “cold spot” surrounds the impact site, where nighttime temperatures run about 14 to 16 degrees Fahrenheit cooler than the surrounding terrain, researchers said. The temperature difference exists because the soil loosened and churned up by the impact doesn’t retain heat as efficiently as undisturbed lunar ground. That cold halo effectively acts as a fingerprint, helping scientists confirm both the location and the freshness of the crater.
Naming and the Science Behind It
NASA officially named the crater McGetchin, honoring Tom McGetchin, a pioneering lunar scientist. The name gives a lasting scientific identity to what is otherwise an extraordinarily rare geological event, one that researchers may not observe again on this scale for generations.
The discovery was detailed across two new studies published on Sept. 16 in the journal Science Advances, according to the study authors. One of those studies, focused on describing the crater itself and the material thrown across the surrounding lunar surface during the impact, was led by Mark Robinson of Intuitive Machines, the study authors said. That ejected material, flung outward when the object struck, offers scientists additional clues about the force and mechanics of the collision.
For context, here is a quick breakdown of the crater’s key measurements:
- Width: 728 feet (about 222 meters)
- Depth: 141 feet (about 43 meters)
- Formation window: between April 11 and May 22, 2024
- Surrounding cold spot: roughly 4 miles wide
- Temperature drop in cold spot: about 14 to 16 degrees Fahrenheit
The find matters well beyond its novelty. Because the Moon lacks weather, plate tectonics, or an atmosphere to erode its surface, impact craters remain preserved almost indefinitely, turning the lunar surface into a kind of historical record of collisions across the solar system. Studying a crater this fresh gives scientists a rare opportunity to examine the immediate aftermath of an impact before space weathering and micrometeorite bombardment gradually alter its appearance over thousands of years.
It also underscores the value of continuous, long-term lunar monitoring. The Lunar Reconnaissance Orbiter’s 2009 launch and its ongoing imaging campaign made this discovery possible in the first place, since spotting a change of this kind requires having a detailed “before” picture to compare against the “after.” Without that archive, an event as significant as the McGetchin impact might have gone unnoticed, hidden among the Moon’s countless other scars.
As researchers continue analyzing the data from both new studies, the McGetchin crater is likely to remain a touchstone for understanding how frequently, and how violently, the Moon’s surface continues to be reshaped.
