Lunar Landscapes
North central portion on the moon; the crater Archimedes on the edge on the Mare Imbrium.
Let’s investigate the landscape of the moon.
The landscape of the moon is remarkably different from any seen on earth. Only a very few places on earth have features that are at all like those on the moon. Does this mean that the methods used for determining the history of lunar landscapes are different from methods used for the earth?
Examine the landscape shown in Figure 1. The Imbrium Basin is the largest basin on the nearside of the Moon, with a diameter of 1160 kilometers (the South Pole-Aitken Basin on the farside is twice as large). The Imbrium Basin is also the second youngest basin on the Moon. Based on samples returned by Apollo 15, it formed about 3.85 billion years ago.
The Face of the Moon
The moon’s appearance; light and dark patches are interpreted as a face in Western culture; “the man in the moon”.
Look at the full moon with binoculars. You will see two major types of landscapes, one dark and the other much lighter. The light areas are generally called highlands or continents-although they are probably quite different from continents on earth. Close examination of the highlands in a photograph like that of Figure 2 shows that the light areas appear very rough because they are covered with craters of all sizes.
The word crater simply means a bowl shaped depression.
The dark areas are much smoother and lower than the highlands. They also contain fewer large craters. Early astronomers called these dark areas maria (MAH-ree-ah), the Latin word for seas, mistaking them for bodies of water like oceans on earth. You can be quite sure, even without high-powered telescopes, that there are no oceans on the moon. The ancient name remains, however, and in fact a new mare (MAH-ray, singular of maria) was named only recently. This area, which was photographed by the Ranger 7 spacecraft, was called Mare Cognitum, the Known Sea.