William sent in the link https://www.msn.com/en-us/weather/topstories/35-000-mph-speeding-rocks-ripped-2-2-mile-deep-canyons-on-moon-in-10-minutes/ar-AA1yrGM0 … but see also https://phys.org/news/2025-02-ancient-asteroid-grand-canyons-moon.html … an asteroid slammed into the Moon, long long ago, and carved out two big canyons on the lunar far side. Scientists, using photographs and data from NASAs Lunar Reconnaissance Orbiter, went on to map the region. The link contends the asteroid raced over the Moon’s south pole before impact. It created a large basin in the process, sending streams of boulders and rocks and hurling them at the speed of one mile a second. The debris, the story goes, landed like missiles, digging out two canyons comparable to the size of Arizona’s Grand Canyon. They are at pains not to upset the uniformitarian nature of the formation of the Grand Canyon, saying it took millions of years to form. Others might disagree. However, when it comes to the Moon, the uniformitarian rules are not in place. Or so it would seem. These two canyons formed in as quickly as ten minutes. Perhaps somebody else will wonder if the Grand Canyon in Arizona may have formed just as quickly – or nearly so.
