The Incredible Shrinking Moon

Back in the 1970’s Paleolithic age of lunar studies, scientists were busy using images of the Moon in an attempt to understand lunar processes and history. In the rugged ancient cratered uplands of the Moon, they saw something curious. Many small scarps dotted the highlands and were visible in only the very highest resolution images [...]

A compressive thrust fault on the far side of the Moon: Is the Moon shrinking? (LROC image)
Back in the 1970’s Paleolithic age of lunar studies, scientists were busy using images of the Moon in an attempt to understand lunar processes and history. In the rugged ancient cratered uplands of the Moon, they saw something curious. Many small scarps dotted the highlands and were visible in only the very highest resolution images and even then, seen only under certain illumination conditions. Moreover, these scarps appeared to cut or overlie small, very young impact craters – young in lunar terms (less than a few hundred million years) not some ancient feature recording an event that occurred billions of years ago.
These highland features looked similar to the Lee-Lincoln scarp found at the Apollo 17 landing site. That scarp crosses the valley floor and trends up ...