Mars today, and how it changed

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How Mars changed

Several million years ago, a turning point occurred in the history of Mars. The tilt of its axis suddenly shifted back to almost about 20 degrees. When this happened the poles began to get cold enough to freeze most of the water, and eventually the CO2 also. As the CO2 was being frozen, the atmosphere grew thinner, and the planet grew colder. As planet grew colder, virtually all of the water and most of the CO2 froze. As the water froze, its level dropped and most of the remaining water flowed underground. Then, even underground it was not warm enough to remain liquid. As a result the water froze underground creating a layer of permafrost.

Mars Today

After the cataclysmic event, Mars' environment was left in ruins. Water no longer flowed freely on the surface, no longer rained down on the mountains. Now, the atmosphere is so thin is is just one step above a vacuum. Violent dust storms sweep along the surface, slowly eroding away the ancient Mars that existed millions of years ago.

The pressure on Mars' surface is less than .5% of the pressure on Earth. Also, because Mars is 50% farther from the sun, it receives only about 40% of the sunlight that Earth receives. As a result, the temperatures are so cold that they can freeze carbon dioxide solid. This frozen CO2, or dry ice, is the main component of the ice caps on the Martian poles. The weather on Mars, instead of consisting of ice and water, consists of CO2 and dust. Today, Mars is a cold, dead world.

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