What are the Physical Features of the Moon?

Answer 1

AnswerThe physical features of the moon include maria - smooth flat plains of basaltic lava, craters, highlands - which make up most of the lunar surface, rills, ejecta - found around an impact crater, and of course, the lunar regolith, a soil-like blanket of fine particles which covers the lunar surface.

Answer 2

The Surface of moon is divided into the mountainous highlands and the large, roughly circular plains called maria (mare; from Lat.,=sea) by early astronomers. The smooth floors of the maria, varying from flat to gently undulating, are covered by a thin layer of powdered rock that darkens them and accounts for the moon's low albedo. The brighter regions on the moon are the mountainous highlands, where the terrain is rough and strewn with rocky rubble. The lunar mountain ranges, with heights up to 25,000 ft (7800 m), are comparable to the highest mountains on earth but in general are not very steep. The highlands are densely scarred by thousands of craters-shallow circular depressions, usually ringed by well-defined walls and often possessing a central peak. Craters range in diameter from a few feet to many miles, and in some regions there are so many that they overlap or several smaller craters lie within a large crater. Craters are also found on the maria, although there are nowhere near as many as in the lunar highlands. Other prominent surface features include the rilles and rays. Rilles are sinuous, canyon-like clefts found near the edges of mountain ranges. Rays are bright streaks radiating outward from certain craters, such as Tycho.

Mare and highland rocks differ in both appearance and chemical content. For example, mare rocks are richer in iron and poorer in aluminum than highland rocks. The maria consist largely of basalt, i.e., igneous rock formed from magma. In the highlands the majority of the rocks are breccias-conglomerates formed from basaltic rock and often studded with small, green, glassy spheres. These spheres probably were formed as the spray of molten rock, originally melted by the heat of meteorite impact, re-congealed in mid-flight. The exposure ages of some rocks (the time their surfaces have been exposed to the action of cosmic rays that produce radioactive isotopes) are as short as 50 million years, much shorter than their crystallization ages. These rocks may have been shifted in position by meteorite impact or seismic activity (moon quakes). However, present lunar seismic activity is very low, corroborating the image of the moon as an essentially static, non-evolving world.