How a Fresh Lunar Crater Became a Natural Impact Laboratory

McGetchin crater formed between April 11 and May 22, 2024, when an asteroid or comet fragment struck the Moon, leaving a cavity about 222 meters across and 43 meters deep.[4] It is the largest newly formed impact crater identified by NASA's Lunar Reconnaissance Orbiter and is roughly three times wider than the mission's previous record-holder.[4][5] Why it matters: LRO's long observational record gives researchers rare before-and-after measurements of a large, pristine impact site, helping them test how ejecta, heat retention and regolith structure change after a collision.[4] Those effects matter for interpreting lunar geology and understanding surface conditions relevant to future landed missions.[4][5] Key insights: Researchers identified the crater in 2025 by comparing LRO images; more detailed observations followed, and the discovery was confirmed in early 2026.[4][5] | The impact produced a roughly 7-kilometer-wide nighttime cold spot that is 8 to 9 kelvins cooler than nearby terrain, probably because disturbed, decompacted regolith retains less heat.[4] | Material was churned across an area extending more than 100 kilometers, while some dust and rock were thrown at higher angles than researchers expected.[5] | The crater lies along a boundary between darker basaltic mare and brighter highlands, allowing scientists to compare the impact's effects across two geological environments.[4] Cheatsheet facts: What changed: A 2024 impact created the 222-meter-wide, 43-meter-deep McGetchin crater, the largest fresh crater yet identified by LRO.[4] | Why now: Two studies published Sept. 16 combined crater imagery and thermal measurements with LRO's more than 17-year record of the lunar surface.[4] | Watch next: Watch for additional orbital or surface observations that connect the mapped ejecta and thermal anomaly with small-scale changes in regolith texture and material distribution.[4]