Martian water has been found in minute traces in the atmosphere as water vapor, in spots on the ground as frost and mixed frozen with rocks in a permanent thick layer called permafrost. It was once thought that the polar caps were ice but their temperature of -113┬║ F is too cold to be frozen water or at least entirely frozen water. The southern cap is purely dry ice, frozen carbon dioxide, year round. The northern cap is composed of water ice thoroughly encased by layers and layers of carbon dioxide that has frozen out of the atmosphere. The water ice is thoroughly buried under dry ice, so it is only detectable in the summer, when the dry ice covering shrinks to its smallest.
Water is found only in minuscule traces on the planet, yet features on Mars indicate the sometime presence of free - flowing water at some earlier time. Channels, images resembling shorelines, and features that look like dried riverbeds point to a time when Mars was a very different world, and liquid water, which current Martian conditions do not allow, was once abundant. So where is this mystery water? What was Mars like when water ran free? Is there a water source, no matter how minimal, that we could tap or rejuvenate for use by future Earthlings on Mars?
As of now, the answers to Mars' most puzzling questions are elusive. No one can fully explain features that suggest mass quantities of water on a planet that, currently, is dry and frozen. Scientists have suggested some theories: perhaps Mars was once warmer or its atmosphere much denser, or perhaps underground water flowing to the surface created such features. The Martian atmosphere and climate may once have allowed enough running water on Mars to cover the entire planet with a pool thirty-three feet deep, but no one knows how or when such drastic climatic and atmospheric changes took place.
Mars continues to harbor secrets about its past. But, since water is essential for life, the evidence of water sometime, somewhere on the red planet does offer hope of one day solving the water puzzle and perhaps finding or sustaining life on the planet.
