1. Education
You can opt-out at any time. Please refer to our privacy policy for contact information.

Mars: The Geography of the Red Planet




In the tradition of ancient geography, this feature describes a far-away and unfamiliar place.

  • Mars is the fourth planet in our solar system and after the earth, it is the planet most hospitable for humans. Its average distance from the sun is 141.6 million miles but it has an elliptical orbit around the sun which ranges from 128.4 (perihelion) to 154.8 million miles (aphelion).
  • With a diameter of 6794 kilometers (4219 miles), Mars is just over half of the diameter of the earth (12,756.3 km).
  • Mars has seasons because, like the earth, it rotates on a tilted axis of 25° while earth's is 23.5°.
  • During a Martian winter, the size of the polar ice cap grows. During the summer, it shrinks. These polar caps are formed mostly of frozen carbon dioxide ("dry ice"). The summers in the southern hemisphere are warmer than the summers in the northern hemisphere.
  • A day (how long it takes Mars revolve once on its axis) is 24 hours and 37 minutes. A Martian year is 687 earth days long - this is how long it takes Mars to revolve around the sun.
  • Mars has latitude and longitude. Of course, 0° latitude is the equator, the dividing line between the northern and southern hemispheres, and 90° north and south are the poles. There's no observatory at Greenwich on Mars so 0° longitude is simply an imaginary line to help us locate Martian features.
  • The surface of the Red Planet has two distinct areas of topography: the Northern Lowlands and Southern Highlands. The Northern Lowlands is an area which displays the results of lava flows, sedimentary deposits and cold weather (periglacial) processes. The Southern Highlands are separated from the Lowlands by a ridge up to two kilometers high and are heavily cratered like the earth's moon.
  • It is hypothesized that earlier in its history, Mars had a much denser atmosphere and thus could have had water on the surface. Currently, the atmospheric pressure on the surface of Mars is equivalent to the pressure 35 kilometers above the surface of the earth. The Martian atmosphere is mostly composed of carbon dioxide (the earth is mostly nitrogen and some oxygen).

©2014 About.com. All rights reserved.