|Diameter||6794 km, 0.53 x Earth's|
|Mean Density||3.94 g/cm3|
|Mean Distance from Sun||228 x 106km = 1.523 AU|
|Eccentricity of Orbit||0.093|
|Inclination of Equator to Orbit||25°|
|Inclination of Orbit to Ecliptic||2°|
|Atmosphere||Very thin carbon dioxide|
|Length of Day||1.02 days|
|Length of Year||687 days|
|No. of Moons||2|
|Gravity||0.38 x Earth's|
|Escape Velocity||5.02 km/s|
Mars is the fourth planet from the Sun and thought to be the most likely to support extra-terrestrial life. Although it is now very cold and has little water, it is believed to have been much warmer and wetter in the past. There is no flowing water on the surface - instead it is trapped in the permafrost and the ice caps. The NASA spacecraft Pathfinder has also photographed a thin icy dew in the mornings.
Marsí equator is tilted to the plane of orbit by about 25 degrees, so it has seasons like Earth, but because the year is twice as long, the seasons also last twice as long.
The surface of Mars is rocky and cratered with huge canyons across it. It is called the Red Planet because of the colour of the dust. This is an orangey-red colour because it contains a lot of oxidised iron (rust).
Some of the canyons that stretch across the surface were created by water that flowed across the planet thousands of years ago. The largest of these, however, was not created by water but by the cracking of the planet's surface. It is called Vallis Marineris and stretches for about 4000 km, or about the same distance as the width of the United States. It is so deep that if you dropped Mount Everest inside it, the mountain would just peek above the top. There are also ice caps at both the North and South poles, made of water and carbon dioxide. These can be seen to grow in the winter and reduce in the summer.
|All Rights Reserved Beagle 2|
Authors: Carolyn Brinkworth and Claire Thomas
Last updated: July 2001