Newly discovered cliffs suggest slight waning over past billion years
The moon has shrunk globally in the past billion years, new high-resolution pictures suggest. The evidence comes in the form of cliffs all over the moon that have formed over the last million millennia like wrinkles on the surface of a dried-out piece of fruit.
Scientists have studied 70 to 80 of these cliffs, called lobate scarps, since the Apollo missions in the ’70s. The scarps are generally tens of kilometers long and less than 100 meters high. Researchers had already hypothesized that the scarps were due to shrinkage, but the Apollo images showed only the moon’s equatorial region. Scientists weren’t sure whether the scarps spanned the entire surface of the moon.