Asteroid Strike Blasts Crater Wide Enough To Swallow City Blocks On Moon
Official deemed McGetchin, the new crater spans roughly 728 feet (222 meters) across and up to 141 feet (43 meters) deep. Larger than the Roman Colosseum, it is the largest recent impact site ever recorded in the solar system. Scientists estimate that a collision of this magnitude occurs on the lunar surface only once every 132 years, making its discovery a statistically rare, once-in-a-lifetime scientific biggie.
It wasn't until researchers conducted routine data comparisons using images captured by NASA’s Lunar Reconnaissance Orbiter (LRO) that the event came to light. Robert Wagner, an LRO mission scientist, noticed an anomalous, glaringly bright spot encircled by a dark halo while processing wide-angle imagery. Subsequent follow-up scans confirmed that the bright feature was not the crater itself, but rather a vast field of reflective blanket material blasted outward during the explosion.
Thermal instruments aboard the LRO, including the Diviner thermal radiometer, revealed a cold spot stretching four miles (seven kilometers) around the crater. Nighttime thermal readings showed this surrounding zone to be roughly 16° F cooler than adjacent terrain. Scientists explain that the violent blast churned up and fluffed the topsoil, decreasing its density and leaving it less capable of retaining thermal energy during the night.
Researchers often compare these impacts to a form of space agriculture that actively gardens the lunar regolith, overturning buried layers and spreading them across the surface. LRO data indicates that ejected material from constant, smaller impacts churns the top inch of lunar soil every 80,000 years, so eventually even things like the footprints left by Apollo astronauts will be erased.
