In the 1960s and ’70s, the U.S. Geological Survey created a Geologic Atlas of the Moon. The series of maps, best viewed while listening to Jefferson Airplane, depicts earth’s only natural satellite in a particularly psychedelic manner, using a full spectrum of colors to show the age and type of rock that makes up the moon’s surface.
The maps were created using a combination of telescopic observations, images captured by lunar orbiters and rangers, and rock samples collected during Apollo missions. They depict the three main topographical features of the moon: craters, highlands, and maria, which are large basaltic plains that formed after volcanic eruptions.
The age of these formations is measured according to the moon’s own geologic time scale, established by astrogeologist Gene Shoemaker. It differs from the geologic time scale of Earth, because it corresponds to impact events that have modified the lunar surface.
The five periods of the moon’s time scale—Copernican, Eratosthenian, Imbrian, Nectarian, and Pre-Nectarian—are also lettered and color-coded on the geologic maps. (Trivia: the study of the surface and physical features of the moon is known as selenography, named after the Greek lunar goddess Selene.)
Author: Ella Morton
Photo credits: lpi.usra.edu