Mars

Fourth major planet from the Sun, high concentrations of iron on its surface cause it to appear red to the naked eye…

DATA

Diameter: 6787km (4217miles)
Mass: (Earth=1) 0.11
Volume: (Earth=1) 0.15
Density: (water=1) 3.94
Orbital Period: 687 Earth days
Rotation Period: 24 Earth hours, 37 mins, 23 seconds
Av. Surface Temp: -23°C (-9°F)

The Planet Mars

The atmosphere of Mars consists of 95% carbon dioxide, 2.5% nitrogen, and 1.5% argon, with smaller quantities of oxygen, carbon monoxide and water vapour. Mars has similar seasons to Earth because of its tilted axis; its surface temperature varies between 130k and 290k, and it reveals a long history of complex geological activity.

The main difference in terrain is between the largely smooth, volcanic plains of the northern hemisphere and the heavily cratered uplands of the south. The biggest volcanic feature on Mars is known on Earth as Olympus Mons, it is hundreds of kilometres across and 27k (17 miles) high. Evidence that rivers once flowed on the planet exists in the form of giant canyons and channels.

Variable polar icecaps appear to be composed of solid carbon dioxide with water-ice lying beneath. Mars has two very small satellites in close orbit, Phobos and Deimos. Earth scientists found fossil remains in a meteorite in 1996 that they believe originated from Mars.