A rock hit the Moon in spring 2024 and opened a crater 222 meters across.[1][2] That is the obvious damage. The stranger part appeared after sunset: a patch of ground about seven kilometers wide became colder than the terrain around it.[3]
This was not leftover chill from a dramatic cosmic event.[3] Quite the opposite. The impact made the lunar soil worse at holding heat.[3]
The crater is called McGetchin.[1][2] Researchers narrowed its birthday to the interval between April 11 and May 22, 2024 by comparing images taken before and after the collision.[1] At 222 meters wide and 43 meters deep, it is the largest newly formed impact crater yet discovered in the solar system.[2] The team’s crater-production model puts an event this large on the Moon at roughly once every 132 years.[2]
Researchers found it afterward. Robert Wagner discovered the crater on October 24, 2025 during a routine data-quality check for the Lunar Reconnaissance Orbiter Camera.[1] His software stacked old and new wide-angle images so unchanged terrain became gray while differences appeared bright or dark.[1] Normally that method produces hundreds of false alarms from shifts in lighting and shadow.[1] This one produced an impact-debris pattern hundreds of pixels across.[1]
There is something pleasingly uncinematic about a once-in-a-century collision entering human knowledge through quality control.
The close-up pictures supplied the crater. A different instrument supplied the more surprising footprint.
Diviner, a radiometer aboard the same orbiter, measured nighttime temperatures around McGetchin.[3] The central crater and nearby rocky ejecta stayed comparatively warm, but around them sat a roughly seven-kilometer cold spot, 8 to 9 kelvin cooler than its surroundings.[3] The paper’s explanation is physical rather than mysterious: the impact decompacted, or “fluffed up,” the upper layer of regolith.[3] Looser material has lower thermal inertia, so it gives up heat more readily during the lunar night.[3]
The hole is 222 meters wide.[2] The thermal disturbance is about 30 times wider.[3]
Even that is not the full reach of the collision. The imaging study found faint changes in how the surface reflects light more than 120 kilometers away, over a thousand crater radii from the rim.[2] The researchers connect those distant marks to high-speed material thrown outward during the first moments of impact.[2] A collision can therefore alter the visible texture of the ground at one scale and its ability to retain heat at another.[2][3]
McGetchin is an unusually large example, but cold spots are not peculiar to it.[3] The Diviner researchers examined 21 newly formed craters larger than 20 meters.[3] Every crater larger than about 30 meters had a detectable cold spot, and larger craters produced stronger temperature anomalies.[3] Their analysis suggests that this broad, shallow disturbance may help remake lunar soil at a rate comparable to the direct churning done by primary craters.[3]
That matters because the Moon is often described as a preserved record, an old surface protected from weather, oceans, and large-scale tectonic recycling. It is a good archive, but not a motionless one. Meteoroids keep editing it. A fresh crater is only the punctuation mark we can see most easily; the sentence around it may be rearranged for kilometers.
McGetchin also offers a rare clean “after” picture. Scientists found it soon enough to study the cold spot before later impacts and space weathering softened the evidence. The warm rocks, cooler loosened soil, and much wider changes in reflectance are three different traces of one event.[2][3]
The crater looks like the main story because it is the part with an edge. The Moon kept the rest of the impact as a change in texture, brightness, and how quickly the ground goes cold.