Planet Mars Facts
the red planet
Mars, aptly nicknamed the Red Planet.
  • Mars is the fourth planet from the sun, its diameter is only around 4,200 miles (6800 km) which is half the size of Earth.
  • It travels around the sun every 687 days and rotates on its own axis every 24 hours 40 minutes.
  • The average distance from Mars to the sun is around 142 million miles (228 million km), one and half times further away from the sun than our planet.
  • The distance between Mars and Earth varies, from as little as 34 million miles (55 million km) to as much as 249 million miles (401 million km).
  • There are vast amounts of water ice under the Martian surface.
  • Evidence shows that water used to flow on the surface of Mars.
  • Mars has seasons just like Earth.
  • Gravity on Mars is around two fifths of that on Earth.
  • Clouds made from frozen carbon dioxide form in the Martian sky, haze and fog are also common.
  • Dust storms on Mars can last for months and can cover the entire planet.

mars surface
Image of the Martian surface captured by NASA's Pathfinder Lander.
Mars Surface
Mars has similar surface features that exist on Earth such as flat plains and sloping hills giving it a rather familiar look. Unlike Earth craters are present all over the planet showing a lack of any major geological activity for possibly billions of years. Evidence of past water are etched out on the planet's surface in the form of huge canyons and river valleys giving us a glimpse of how different the planet may have looked in the distant past. Mars also has huge extinct volcanoes, the largest of which is three times higher than Mount Everest. The planet gets its reddish color from the presence of iron-oxide, otherwise known as rust.
Mars has polar caps primarily composed of water ice but covered in a layer of frozen carbon dioxide. In the warmer periods of its year the carbon dioxide evaporates in the northern pole revealing the frozen water below.
Mars Temperature
Surface temperatures on Mars vary from as low as -125C (-195F) near the poles to around 20C (68F) at midday near the equator. The highest recorded air temperature on Mars is 35C (95F).

Mars Atmosphere
The thin atmosphere of Mars is only around 1% the density of our own atmosphere, consisting of 95% carbon dioxide. With atmosphere comes weather, strong winds can produce massive dust storms, dust devils are created by warm daylight air rising from the surface, faint clouds form in the Martian sky and even snow falls in the form of frozen carbon dioxide.

Mars has two very small moons, Phobos which has a diameter of 17 km (28 km) and Deimos which has a diameter of 9 miles (15 km). It is probable that they were once asteroids that were caught by the gravity of the planet.
Life on Mars
Mars may once have harbored life and may still do today. Most likely life could exist in warm pockets beneath the ground, methane has been detected in the Martian atmosphere which could have been produced biologically. In the summer months the amount of methane increases dramatically giving further credence to this theory.
Origin of Name
Mars is named after the Roman God of War.

Colonizing Mars

mars domes
A future Mars colony using inter connecting domes
When considering planets in the solar system that mankind can colonize there really only is one candidate. The two rocky planets close to the sun, Venus and Mercury, are baking hot infernos and the gas giants such as Jupiter and Saturn have no solid surface. So that leaves us with Mars, even though it is extremely inhospitable to humans in most respects it is by far the most Earth like when compared to the other planets of our solar system.

The red planet has many qualities that make it attractive to prospective colonizers such as its closeness to Earth, the familiarity of a 24 hour day or the fact that Mars has seasons just like on Earth. Undoubtedly though the most important quality is the abundance of water on Mars. Underneath its surface lies a thick layer of water ice, apart from its obvious uses such as drinking, cooking and hygiene, water can also be used for energy, such as rocket fuel by separating the hydrogen and oxygen.

Bases could be built on Mars in the form of interconnecting reinforced domes which allow for the largest space with the least amount of materials. Colonies would eventually become completely self sufficient, growing their own food, perhaps hydroponically, without the need for soil. Mars could also be used as a base for mining the incredible mineral wealth of the asteroid belt, the iron taken from there could be used to build more structures on the surface without the need of supplies from Earth, which could see colonies rapidly grow.

Of course there are many hazards on Mars, the thin atmosphere gives little protection from the suns rays so radiation levels are very high. Temperatures even in the warmest areas of Mars can dip below -60C (-80F) and there are frequent massive dust storms, you don’t want to be going for a walk on Mars unless you are very well protected. Another factor that needs to be taken into account is that gravity on Mars is only around two fifths of what we experience on Earth, this may not be enough to stop our bones and muscles from deteriorating, daily exercise may have to be part of a colonizers routine.

Even with all the dangers Mars poses there would be no shortage of volunteers to become 21st century pioneers. Many will not be able to resist the lure of visiting an alien planet, witnessing a red sky or visiting the breathtaking canyons and volcanoes that exist on Mars.

mars sunset
Spectacular image of a Martian sunset taken by NASA's rover Spirit.
Planet Mars Statistics

Diameter: 4,212 miles (6,779 km)
Average Distance from Sun: 142 million miles (228 million km)
Orbital Period: 687 days
Rotation Period: 24.62 hours

Maximum Surface Temperatures: 20C (68F)
Minimum Surface Temperatures: -125C (-195F)

Gravity: 3.693 m/s2 (38% Earth's Gravity)
Density: 3.94 g/cm3 (71.4% Earth's Density)
Mass: 6.4185 x 1023 kg (10.7% Earth's Mass)
Volume: 1.6314 x 1011 km3 (15% Earth's Volume)

Atmosphere: 95.32% carbon dioxide, 2.7% nitrogen, 1.6% argon, 0.13% oxygen, 0.08% carbon monoxide.