How NASA Found a New 222-Metre Crater on the Moon
This article explains how a routine map check revealed a newly formed 222-metre crater on the Moon, why the find is unusual, and what it says about impact rates.
A Bright Spot Where Nothing Should Have Changed
Robert Wagner was running a quality check on a global map of the Moon. The work is almost always uneventful. It means stacking hundreds of wide-angle frames taken years apart, so software can grey out everything unchanged and show anything new as a bright or dark patch. On one pass, the software flagged a bright spot ringed by a dark halo. It was a crater 222 metres wide on the Moon’s eastern near side, the side that faces Earth. It had not existed before spring 2024.
NASA Science described the crater as a once-in-a-century find. CBS News noted the 222-metre feature is bigger than the Roman Colosseum. The crater, named McGetchin, is the largest newly formed impact crater yet found anywhere in the solar system, according to Space Daily.
What the Before-and-After Images Show
The impact was not recorded as it happened. It was detected by comparing images taken at different times. The before-and-after frames bracket a 41-day window, narrowing the moment of impact to that stretch of time.
The discovery came from the sort of work that is expected to catch calibration errors and data glitches, not a major new crater. The bright central patch and dark halo were exactly the kind of change the map comparison software is meant to make visible.
Why a Single Crater Matters
Crater production models predict that an impact of this size on the Moon happens about once every 132 years on average. McGetchin is the largest crater known to have formed while astronomers were watching, based on a seventeen-year archive of orbital images. Set against a lunar surface that is billions of years old, that archive is short. But it was long enough to catch a rare event.
The find is also a reminder that the Moon is not a static world. New craters are still being cut into its surface, and routine data processing can uncover them. The largest newly formed crater found anywhere in the solar system was not revealed by a dedicated search. It showed up in a map that was already being built, during a check meant to catch changes of any kind.