This is an image of Mars. Click on image for full size version (40K GIF) Image from: NASA

Unlike that of the Earth, the Martian climate is significantly influenced by the eccentricity of the Martian orbit. In spite of the significant influence the orbit plays on Martian climate over the years however, the primary factor determining the climate of Mars, has been the presence of water near the surface, or lack thereof.

On a cold planet, frozen water can be trapped within the ground, like the frozen tundra of the Earth. This ground water can be released in periodic episodes when Mars undergoes changes in climate.

This phenomena may explain the evidence for running water seen on the surface of Mars. In all likelihood, over the history of Mars, water has been continuously drawn from higher underground latitudes to lower underground latitudes. This phenomena has to do with the unusual global geography of Mars, which helps scientists piece together the nature of the Martian cryosphere, or topography of frozen ground.

This is an image of Mars. Click on image for full size version (40K GIF) Image from: NASA

The unusual climate of Mars makes Mars not quite right for life as we know it on Earth. If the climate were warm enough, water would not freeze into the ground but vaporize into the atmosphere. Lots of water vapor in the atmosphere would help keep Mars warm, and prevent water from freezing.

On a cold planet water can be frozen into the ground, like the frozen tundra of the Earth, and therefore trapped. This ground water can only be turned into running water when the climate of Mars undergoes a change.

Over the history of Mars, when the climate changes due to the unusual shape of its orbit, water, which has been stored, frozen, underground, turns to running water and is transferred from regions near the poles to regions near the equator. This phenomena has to do with the unusual global geography of Mars. Scientist think there are two possiblities for how it happens.

Ultimately, as Mars cools off, climate changes are not enough to prevent the water from being permanenty frozen into the ground.

This is an image of Mars. Click on image for full size version (40K GIF) Image from: NASA

Mars is not quite right for life as we know it on Earth.

On a cold planet like Mars, water can become frozen into the ground. This water can only be turned into running water when the weather is warm enough.

Over the history of Mars, there seems to be evidence that it has been warm enough for running water on Mars.

As Mars cools off though, it seems that warm weather is not enough to prevent the water from being permanenty frozen into the ground.