Mars
Mars is also called the red planet because of its red surface. We didn't know sure how is its structure, but the most likely facts are that Mars have a dense core about 1700 km in radius, a molten rocky mantle somewhat denser than the Earth's and a thin crust. Though Mars is much smaller than Earth, its surface area is about the same as the land surface area of Earth.
Much of the Martian surface is very old and cratered, but there are also much younger rift valleys, ridges, hills and plains.There is very clear evidence of erosion in many places on Mars including large floods and small river systems, and it proves that at some time in the past there was clearly some sort of fluid on the surface. Liquid water is the obvious fluid but other possibilities may exist.There may have been large lakes or even oceans. Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide (95.3%) plus nitrogen (2.7%), argon (1.6%) and traces of oxygen (0.15%) and water (0.03%)
Like Mercury and the Moon, Mars appears to lack active plate tectonics at present.
Much of the Martian surface is very old and cratered, but there are also much younger rift valleys, ridges, hills and plains.There is very clear evidence of erosion in many places on Mars including large floods and small river systems, and it proves that at some time in the past there was clearly some sort of fluid on the surface. Liquid water is the obvious fluid but other possibilities may exist.There may have been large lakes or even oceans. Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide (95.3%) plus nitrogen (2.7%), argon (1.6%) and traces of oxygen (0.15%) and water (0.03%)
Like Mercury and the Moon, Mars appears to lack active plate tectonics at present.