Earth's moon is shrinking and quaking, study says

[Guest Indiana]

(CNN)The moon is slowly shrinking over time, which is causing wrinkles in its crust and moonquakes, according to photos captured by NASA's Lunar Reconnaissance Orbiter.

Unlike Earth, the moon doesn't have tectonic plates. Instead, as the moon's interior has cooled over the last several hundred million years, it has caused the surface to wrinkle as it shrinks. Unlike the flexible skin of a grape when it shrinks into a raisin, the moon's brittle crust breaks. This creates stair-step cliffs called thrust faults as part of the crust is pushed up and over another close part of the crust.

There are now thousands of cliffs scattered across the moon's surface, averaging a few miles long and tens of yards high. The orbiter has taken photos of more than 3,500 of them since 2009. In 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt had to ascend one of these cliffs, the Lee-Lincoln fault scarp, by zig-zagging the lunar rover over it.

https://edition.cnn.com/2019/05/13/world/moon-shrinking-quakes-scn/index.html

This is a view of the Taurus-Littrow valley and its cliffs, explored by Apollo 17 astronauts.