NASA's Lunar Reconnaissance Orbiter Finds a 222-Metre Crater That Formed on the Moon in 2024

It began with an odd pattern on a map of the Moon: a bright spot ringed by a dark halo. Robert Wagner, an image-processing specialist working with data from NASA's Lunar Reconnaissance Orbiter Camera (LROC), was running a routine data-quality check on Oct. 24, 2025, when the feature stopped him.

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"I just stopped, dropped everything, and started looking into what that spot was," Wagner said in NASA's account of the find.

It turned out to be the largest newly formed impact crater ever identified in the solar system, according to NASA and the LRO science team, who reported the discovery on Sept. 16, 2026, in two papers in the journal Science Advances.

The crater, now named McGetchin, measures about 222 metres (728 feet) across and up to 43 metres (141 feet) deep. It formed on the Moon's eastern edge, near the border between dark volcanic plains and brighter highland crust, sometime between April 11 and May 22, 2024. The object that carved it was likely a fragment of an asteroid or comet roughly the size of a three- to six-story building.

The name honors Thomas McGetchin, a volcanologist and lunar scientist who helped shape the modern understanding of how impact ejecta spreads across a landscape. The International Astronomical Union adopted it on May 4, 2026, on a proposal from the LROC team, and the 1973 framework McGetchin developed for ejecta deposits is still a reference point for reading craters. The crater that now carries his name is testing parts of that framework.

A crater that appeared between two sets of images

Finding a new crater on the Moon is usually a job of subtraction. LROC's Wide-Angle Camera (WAC) photographs broad swaths of the surface with pixels the size of football fields. When the team stacks hundreds of frames taken months or years apart and compares them, anything unchanged turns gray while anything new shows up as a bright or dark patch.

Wagner was reviewing one of those temporal-ratio maps when the McGetchin signature appeared: a white spot, made by freshly thrown ejecta, inside a darker halo of disturbed ground. "It was by far the most obvious impact debris pattern I've ever seen in one of these images," he said.

The software that builds those maps flags every small shift in lighting or shadow, producing hundreds of false alarms, so the LROC team still checks candidates by eye. A real crater often shows up as a small, fuzzy halo around a pixel-wide bright point, the signature of regolith splashed out by an impact.

Once the site was identified, the team turned to LRO's Narrow-Angle Camera (NAC), which images at roughly 3 feet (about 1 metre) per pixel. LROC had taken pictures of that spot before the impact but none after, so the cameras were re-pointed at the location during passes over the following months. The first overhead close-up of McGetchin used here was captured on Dec. 5, 2025, and it showed the crater's size, its shape and the way the surrounding terrain had been rearranged.

That before-and-after pairing is a large part of why the discovery matters. Most craters studied on the Moon are ancient, their original surfaces worn down by billions of years of further impacts and space weathering. McGetchin is young enough that its fresh morphology, ejecta blanket and interior detail remain intact, giving scientists a rare natural test of how cratering works.

A cold spot miles wide

LRO carries more than cameras. Its Diviner instrument measures surface temperature, and after the discovery the Diviner team re-examined the site. It found a cold spot roughly 4 miles (about 7 kilometres) wide around the crater, where nighttime temperatures run about 16 degrees Fahrenheit (8 to 9 kelvin) below the surrounding landscape.

That cooling is a consequence of what the impact did to the regolith, the loose layer of dust and broken rock that covers the Moon. The blast decompacted the upper surface, fluffing it up and making it less dense, so it holds heat poorly after sunset. The result is a thermal fingerprint that fades over hundreds of thousands to a million years, which makes cold spots a useful way to find young craters.

The Diviner analysis, led by Tyler M. Powell, examined 21 newly formed craters larger than 20 metres and found that every one wider than about 30 metres produced a detectable cold spot, with larger craters creating stronger anomalies. Because McGetchin sits on the contact between two very different rock types, its cold spot offered a natural experiment: the anomaly stretched across both mare and highland terrain and was strikingly symmetrical, suggesting the top few centimetres of regolith behave similarly no matter what lies beneath.

LRO was not built to record seismic waves, but the event also points to the Moon's activity beneath the surface. Large impacts release energy as ground motion, and connecting an observed crater to the shaking it produced is part of how scientists build a picture of the lunar subsurface.

Disturbance far beyond the rim

The second surprise was how far the impact's effects reached. The study led by Mark S. Robinson, the LROC principal investigator at Intuitive Machines, reports surface modification extending more than 1,000 crater radii from the impact point, and the LROC team detected reflectance changes more than 100 kilometres away.

Those distant marks are not piles of debris hurled from the hole. The impact appears to have changed the texture of the surface across a vast area, reshaping material well beyond the continuous ejecta blanket that surrounds the rim. The LROC team also found evidence that the high-speed jetting of material off the surface happened at steeper angles than models had assumed, above 10 degrees rather than the roughly 2 degrees previously considered typical, and that the ejecta was deposited in at least two flows.

Scientists say that kind of detail is exactly what a well-imaged fresh crater provides: a check on models describing everything from first contact to the collapse of the crater walls. McGetchin's measured dimensions, a 222-metre average diameter, a 43-metre depth, wall slopes averaging 24 degrees and a rim about 8 metres high, line up closely with existing models, the LROC team reported.

Why a single fresh crater matters

Impact rates are one reason. The Moon has no atmosphere to burn up incoming objects, so its surface is a long-running record of collisions. LRO has identified at least 1,000 new impact craters over more than 17 years and flagged about 100,000 other surface changes. Scientists estimate that impacts large enough to leave a crater about 30 feet wide happen roughly 140 times a year across the Moon, though most are too small to spot from orbit.

McGetchin is a different order of event. Models predict a crater of its size forms about once every 132 years on the Moon, which is why NASA and the papers call it a once-in-a-century find. Before this discovery, the largest fresh crater identified during the LRO mission was about 70 metres across, less than a third of McGetchin's diameter.

Fresh craters also help calibrate how scientists date surfaces. Planetary scientists estimate the age of a landscape by counting craters, on the logic that more craters means an older surface. That method depends on knowing the rate at which new ones appear, and a dated crater of known size is a direct measurement of that rate.

The findings carry a practical dimension for exploration as well. NASA frames the discovery in the context of its push for a sustained human presence on the Moon under Artemis. A 2024 impact that excavated rock and soil and disturbed the regolith far beyond its rim is a reminder that the lunar surface is an active environment. The material thrown outward, and the loosened ground left behind, could affect how rover wheels grip the surface and how equipment and habitats are designed to withstand high-speed particles arriving from distant impacts.

For planners, the rare large strike is not the only hazard. Smaller particles thrown outward at high speed can damage hardware, and the McGetchin event suggests those particles can travel farther and arrive at steeper angles than older models assumed. That is a design input for landers, rovers and, eventually, habitats.

LROC's ability to find McGetchin at all rests on repetition. The camera system has returned images of the Moon for more than 17 years, building an archive detailed enough to isolate a single new feature on a surface hundreds of miles wide, the scale of the global map Wagner was reviewing. That archive is the reason a 2024 impact could be identified at all, and it is why NASA treats the long-running mission as infrastructure for future lunar work rather than a one-off survey.

What the discovery does not show

The "largest ever identified" label is a statement about the record, not the universe. It means no larger freshly formed crater has been found since scientists began comparing lunar images, not that impacts of this size are unprecedented in the solar system's history. Likewise, the once-in-a-century estimate comes from crater-population models rather than from watching many such events.

Some details remain open. Researchers expect a future paper to estimate the size and force of the impactor, and the work of translating one well-studied crater into better predictions will continue. For now, McGetchin offers something rare: a clear, dated mark left on another world in an era when humans were watching closely enough to notice it.

A future mission could study the site up close. For the teams behind LRO, which launched in 2009 and has now been mapping the Moon for more than 17 years, the crater is also a validation of the long, patient business of taking the same pictures again and again and looking carefully at what changed.

Credit: Cover image of McGetchin crater from NASA's Lunar Reconnaissance Orbiter Narrow-Angle Camera (Dec. 5, 2025). Credit: NASA/Goddard Space Flight Center/Intuitive Machines. NASA imagery is generally not subject to copyright in the United States.