A Routine Data Check Led to the Solar System's Largest Newly Formed Crater

A Chance Discovery That Rewrote the Record Books

On October 24, 2025, Robert Wagner, a scientist with NASA's Lunar Reconnaissance Orbiter, was scanning a giant moon map on his computer screen during routine quality checks when he noticed a large, bright spot with a dark halo — a sign that the surface had been disturbed. It looked unusual. It was. Wagner had just discovered the largest newly formed impact crater ever documented in the solar system.

The white spot was not the crater itself, but rather material flung out of the crater, which formed when a rock possibly the size of a three- to six-story building crashed into the Moon between April 11 and May 22, 2024 — a once-in-a-century event, as scientists reported on September 15, 2026, in a pair of papers in Science Advances. The impact had happened more than a year before anyone on Earth knew about it. The moon strike escaped real-time detection by telescopes on Earth and in space.

The Numbers Behind the Discovery

The crater, named McGetchin after lunar scientist Thomas McGetchin, measures 728 feet wide and 141 feet deep — roughly the size of two American football fields. To put the depth in perspective, it could swallow three school buses stacked vertically. The crater is three times bigger than the previous record-holder found by the LRO a decade ago.

An impact capable of producing a crater this size is expected to occur on the moon only about once every century, making McGetchin an exceptionally rare real-time discovery. According to LRO camera chief scientist and lead study author Mark Robinson, the impact blasted rock and dust across a radius exceeding 66 miles. Dust and rocky soil were hurled away at a higher angle than expected. Researchers noted that the fastest ejected material must have launched at steeper angles than standard models typically assume.

A Cold Scar Left Behind

A secondary study published in Science Advances and led by researcher Tyler Powell revealed a broader thermal anomaly surrounding the impact site. Data from LRO's thermal instrument, Diviner, identified a 4.3-mile-wide "cold spot" encircling the crater. During the lunar night, this region registered temperatures 14 to 16 degrees Fahrenheit colder than adjacent terrain.

Researchers say the cooling happens because the impact fluffs up the regolith — the loose surface rocks — around the crater, which makes it less dense and unable to hold heat. In other words, the collision didn't just carve a hole — it fundamentally altered the physical properties of the surrounding landscape. This shows a big impact can alter the Moon's surface far beyond the crater rim.

Honoring a Legacy, Informing the Future

The crater is named after Thomas R. McGetchin (1936–1979), an American geologist and planetary scientist who became director of the Lunar Science Institute in 1977, which was renamed the Lunar and Planetary Institute under him. The LRO camera team proposed the name, and the International Astronomical Union approved it on May 4, 2026. The naming carries a certain poetry — Robinson and colleagues actually used an ejecta model McGetchin published with co-authors in 1973 to estimate how much of the new rim is ejecta. His science helped explain his own crater.

Such a large-scale event is estimated to occur only once every 132 years, making this a treasure trove of information as NASA prepares to build a base for astronauts on the moon. The newly identified crater is tiny compared to ancient lunar structures, but its recent formation makes it particularly important to researchers. Unlike ancient craters whose original features have been modified over immense periods, this impact offers scientists a relatively fresh look at how an incoming space object excavates, redistributes, and reshapes lunar soil. For a space agency planning to send humans back to the lunar surface, understanding how the ground beneath their feet can be suddenly and violently remade is not just scientific curiosity — it's mission-critical knowledge.