Mars is the fourth planet from the Sun and the seventh largest:
Though Mars is much smaller than Earth, its surface area is about the same as the land surface area of Earth.
Distance from the Sun: 227,940,000 km (141,500,000 miles or 1.52 AU)
Period of Revolution: 687 days
Diameter: 6,794 km (4,200 miles)
Mass: 6.4219e23 kg
Satellites: 2- Phobos and Deimos
Mars is the god of War. The planet probably got this name due to its red color; Mars is sometimes referred to as the Red Planet. The name of the month March derives from Mars.
Mars has the most highly varied and interesting terrain of any of the terrestrial planets, such as:
Like Mercury and the Moon, Mars appears to lack active plate tectonics; there is no evidence of horizontal motion of the surface such as the folded mountains so common on Earth. With no lateral plate motion, hot-spots under the crust stay in a fixed position relative to the surface. This, along with the lower surface gravity, may account for the Tharis bulge and its enormous volcanoes. There is no evidence of current volcanic activity, however. And though Mars may have been more volcanicly active in the past, it appears to never have had any plate tectonics.
There is very clear evidence of erosion in many places on Mars including large floods and small river systems. At some time in the past there was clearly water on the surface There may have been large lakes or even oceans. But it seems that this occurred only briefly and very long ago; the age of the erosion channels is estimated at about nearly 4 billion years.
Early in its history, Mars was much more like Earth. As with Earth almost all of its carbon dioxide was used up to form carbonate rocks. But lacking the Earth's plate tectonics, Mars is unable to recycle any of this carbon dioxide back into its atmosphere and so cannot sustain a significant greenhouse effect. The surface of Mars is therefore much colder than the Earth would be at that distance from the Sun.