When scientist spotted once-in-century Moon crater

NASA's Lunar Reconnaissance Orbiter (LRO) has stumbled upon a remarkable discovery - a 728-foot wide crater that didn't exist a few years ago. Robert Wagner, an image-processing specialist from Intuitive Machines, came across the anomaly while reviewing lunar maps. Recognizing the bright patch surrounded by a dark halo, he immediately delved into the matter.

Comparing old and new images, Wagner confirmed that the feature was a brand-new impact crater. The team has since reported this finding in Science Advances, noting that it is the largest newly formed crater ever identified in the solar system.

The crater, named McGetchin in honor of pioneering lunar scientist Tom McGetchin, formed near the Moon's eastern edge between April 11 and May 22, 2024. It resulted from an asteroid or comet roughly the size of a three- to six-story building striking the lunar surface. With a diameter of 728 feet and a depth of 141 feet, McGetchin could potentially hold three yellow school buses stacked vertically.

This crash might not have been the first of its kind. Researchers estimate that such large impacts occur on the Moon only once every century, if that. LRO, which has been orbiting the Moon for over 17 years, has identified at least 1,000 new impact craters and recorded about 100,000 additional changes to the surface caused by impacts or ejected debris. The Moon lacks an atmosphere to slow down incoming space rocks, so objects can strike its surface directly.

Further investigation using LRO's thermal instrument, Diviner, revealed an unexpected discovery. An area roughly 4 miles wide around McGetchin is about 16 degrees Fahrenheit colder at night than the surrounding terrain. This 'cold spot' is thought to be due to changes in the lunar regolith - the loose material ejected during the impact. The impact disrupted and loosened the surface material, making it less dense and less capable of retaining heat after sunset.

This discovery could have practical implications for future lunar exploration. Variations in the regolith's texture and density might affect how rover wheels navigate the surface. LROC, the system that captured McGetchin, photographs the Moon from about 60 miles away while orbiting pole-to-pole. It includes cameras capable of capturing detailed black-and-white images and moderate-resolution multispectral images.

These observations have allowed scientists to assemble precise maps of the lunar surface, identifying features such as new craters, landslides, spacecraft landers, seismic faults, and potential lava tubes.