"I just stopped, dropped everything": NASA scientist recalls spotting a mysterious bright spot on Moon that turned out to be a once-in-century crater

It was a routine data-quality check that no one know would turn into a remarkable NASA Moon discovery. The striking discovery came to light after scientist Robert Wagner noticed an unusual bright spot surrounded by a dark halo while scanning a massive map of the lunar surface. “I just stopped, dropped everything, and started looking into what that spot was,” Wagner said. At the first glance, it appeared likely as a strange mark eventually turned out to be a newly formed lunar crater, created when a comet or asteroid slammed into the Moon sometime in 2024. According to scientists, the impact impact capable of producing a crater of this size happens only about once every century or even longer. The discovery, reported in Science Advances, also shows how NASA's Lunar Reconnaissance Orbiter (LRO) continues to uncover changes taking place on the Moon.

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NASA scientist notices strange spot on Moon

Wagner, an image-processing specialist from Intuitive Machines who works with data from the Lunar Reconnaissance Orbiter Camera (LROC), was not initially searching for a new crater. He was carrying out a routine data-quality check when something unusual caught his attention on a giant map of the Moon. A bright spot surrounded by a darker halo appeared to indicate that lunar surface material had been disturbed. Curious to understand what it was, Wagner began investigating it and comparing images of the same location taken at different times.

“I just stopped, dropped everything, and started looking into what that spot was,” he said. The before-and-after images provided the crucial clue. The feature had not been present in earlier observations, meaning scientists were looking at a relatively recent change on the Moon.

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The crater has officially been named McGetchin, after Tom McGetchin, a pioneering lunar scientist. Scientists determined that the impact happened on the eastern edge of the Moon sometime between April 11 and May 22, 2024. The object responsible was likely a comet or asteroid measuring roughly the size of a three- to six-story building.

When it struck the lunar surface, it created a crater approximately 728 feet wide and 141 feet deep. For perspective, the crater is about as long as two football fields. Its depth would be enough to fit three yellow school buses stacked vertically. Scientists estimate that an impact capable of producing a crater of this magnitude occurs on the Moon approximately once every 100 years or longer.

Why so many objects hit the Moon

The Moon has no atmosphere capable of significantly slowing down incoming space rocks or burning them up before they reach the surface. That leaves the lunar landscape exposed to impacts from asteroids, comets and other objects traveling through space. Most of these collisions are much smaller than the one that created McGetchin crater. NASA's Lunar Reconnaissance Orbiter has been circling the Moon for more than 17 years, using seven instruments to study the lunar environment.

During that time, scientists have identified at least 1,000 new impact craters and detected about 100,000 other surface changes caused by impacts or debris thrown outward during collisions. The smallest craters scientists can distinguish in LRO images are approximately 30 feet wide. They can be created by rocks around 43 inches across, roughly the size of a monster-truck tire.

Scientists estimate that impacts producing craters of this detectable size happen around 140 times a year across the Moon. However, many smaller impacts leave marks that are too tiny to identify in images captured from lunar orbit.

NASA's Moon orbiter found more clues

For more than 17 years, LRO has been circling the Moon and using its seven instruments to map the topography, surface composition, temperature, and radiation environment there. The spacecraft’s team has identified at least 1,000 new impact craters throughout the mission and flagged 100,000 more surface changes from an object smashing into the Moon or from the debris that flung out after.

With no atmosphere to slow them or burn them up, space rocks and other objects easily reach the lunar surface. Most are much smaller compared to the object that carved out McGetchin crater. The smallest craters scientists can distinguish from LRO images are about 30 feet wide, the length of a three-story building laid on its side, made by rocks about 43 inches wide, the size of a monster-truck tire. Scientists estimate that impacts of this scale produce about 140 new craters across the Moon each year. But most new ones are made by microscopic projectiles that leave holes too small to identify in orbital images.

With its numerous instruments, the spacecraft can observe changes to the lunar surface that aren’t apparent in the LROC images alone. After the crater was discovered, scientists working with LRO’s thermal instrument, Diviner, made follow-up observations of the site. They found a 4-mile-wide area around the crater that is about 16 degrees Fahrenheit cooler at night than its surroundings.

The large extent of this “cold spot” is striking, scientists say, because it shows that impacts can modify the Moon’s surface far beyond the crater itself. These physical changes could affect how rover wheels interact with the surface, for instance.

Because NASA's LRO had already been monitoring the Moon, scientists could compare older images with newer ones and identify exactly where the surface had changed. Such observations help researchers understand how quickly the Moon's landscape changes and how impacts reshape its surface.

The discovery also highlights the importance of long-term lunar monitoring. A feature that appeared unexpectedly during a routine data check could have been difficult to identify without years of observations covering the same areas.