Surface of the Moon
Ancient observers of the Moon believed that the dark regions on its face were oceans, giving rise to their name maria (Latin for “seas”). This term is still used today although these regions are now known to be completely dry. The brighter regions were held to be continents. Modern observation and exploration of the Moon has yielded far more comprehensive and specific knowledge. The Moon has no movement of wind or water to alter its surface, yet it was geologically active in the past and is still not totally unchanging. Craters cover the surface, and meteors continue to create new craters. Billions of years ago volcanic eruptions sculpted large areas of the surface. Volcanic features such as maria, domes (low, rounded, circular hills), and rilles (channels or grooves) are still discernable. Scientists have also recently discovered evidence of ice in permanently shadowed areas of the surface. See: Craters ; Volcanic Features ; Ice