What Makes Up Mercury's Surface?
Mercury is the smallest of the eight recognized planets in the solar system, a world that is hard to observe from Earth due to its proximity to the Sun. The surface of Mercury is believed to be made up of the same type of silicate rocks that are found on the surface of the Earth, and the theory is that the planet has a dense core that is 70% iron. The features of Mercury have not been totally mapped, but astronomers have a good idea of what the planet is like on the surface in regards to its features. In many ways, it resembles our own Moon.
History
Scientists theorize that after Mercury formed, the planet developed a very large core of iron covered by a relatively thin mantle. As lava flowed up through cracks in the rocks, it formed the plains. There were repeated strikes on Mercury by meteors that caused craters and basins. Volcanic activity then created more of Mercury's surface features, such as the smooth plains. Mercury is felt to be very stable in term of geological activity since the volcanic activity ceased.
Features
Mercury has a surface with a variety of features of interest. There are craters, ridges, and entire plains free of any landscape at all. No volcanoes have been seen as yet but their presence, at least in the past, is indicated by the smoothness of some of the plains, suggesting they were formed by lava. The ridges were more than likely the result of Mercury experiencing some cooling in its early stages, with the contraction of rock forming the structures. One side of the planet appears to have many more craters than the other.
Types
One of the single largest features on Mercury's surface seen so far is known as the Caloris Basin. The crater was caused by a large meteorite in the infancy of the planet and is more than 1,500 kilometers across. The Caloris Basin is surrounded by a two-kilometer-high wall of debris from the impact's force. Other basins on Mercury are in the range of 400 to 800 kilometers across.
Geography
Mercury has a very large number of what are classified as "wrinkle ridges" from the aforementioned cooling and subsequent contraction of the planet. They criss-cross the plains and craters, which means that they formed after many of the other features of Mercury's surface did.
Considerations
Mercury has no atmosphere to speak of. This means that the surface of Mercury is totally at the mercy of the Sun. Since Mercury takes almost 59 days to rotate once on its axis, the side facing the Sun is incredibly hot, almost 800 degrees Fahrenheit. But with no air to spread the heat around to the "dark side" of Mercury the temperatures there fall to more than 300 below.
Tags: Mercury surface, features Mercury, more than, Caloris Basin, features Mercury surface
