Scientists have identified a crater on the moon larger than the Roman Colosseum, formed from a powerful impact two years ago that went unnoticed initially. The crater, measuring 222 meters across and up to 43 meters deep, is the largest known recent impact crater in the solar system. Such large-scale events are rare, occurring roughly once every 132 years, providing valuable insights as NASA prepares for a lunar base.
The discovery was made by NASA’s Lunar Reconnaissance Orbiter (LRO) in May 2024 on the moon’s near side, following an asteroid or comet fragment impact. The crater, named after Thomas McGetchin, the late director of Houston’s Lunar and Planetary Institute, was confirmed early this year after LRO’s detailed images were analyzed.
This impact, affecting over 100 kilometers of the lunar surface, ejected dust and rocky soil at unexpectedly high angles. Mark Robinson, the lead author of one of the studies, described the event as akin to gardening the moon’s regolith – the loose material above bedrock. Another study found a cold spot around the crater, indicating loosening of the moon’s topsoil.
According to Robinson, the LRO’s findings suggest the moon’s topsoil is overturned every 80,000 years by ejected material, faster than previously believed. Contrary to popular belief, the footprints left by Apollo moonwalkers will not endure for long. The next phase involves assessing the risk of ejected material hitting NASA’s future moon base to enhance structural resilience.