The boiling point depends on the pressure and if it is excessively low, the water can not exist in liquid form. That’s what happens on Mars if the planet had abundant water courses was because it also had a much denser atmosphere also providing higher temperatures. To dissipate most of the atmosphere in space, thereby reducing pressure and decreasing temperature, the water disappeared from the surface of Mars. However, there remains in the atmosphere as vapor, although in small proportions, and in the polar caps, consisting of large masses of permafrost.
Everything suggests that the grains of soil there is frozen water, a phenomenon which, moreover, is common in very cold regions of Earth. Around certain Martian craters are observed as a formation of lobes whose formation can be explained only by admitting that Martian soil is frozen. Also available are photographs of another type of accident of the relief well explained by the existence of a permafrost. It is a land subsidence of as part of a dry riverbed depression with the imprint of his arms separated by alluvial banks.
It is also found in crater walls or deep valleys where sunlight never falls, accidents that look like gullies formed by torrents of water and deposits of soil and rocks transported by them. They only appear in high latitudes of the Southern Hemisphere.
The comparison with the earth’s geology suggests that it is the remains of a surface water supply similar to an aquifer. In fact, the Mars Reconnaissance Orbiter has detected large glaciers buried with extensions for dozens of miles and depths of about 1 kilometer, which extend from the cliffs and hillsides that are at latitudes lower than expected. The same probe also found that the northern hemisphere of Mars has a larger volume of water helada.7
Further evidence for the existence of large amounts of water in the martian past in the form of oceans that covered a third of the planet has been given by the gamma ray spectrometer aboard Mars Odyssey, which has identified what seems to be the coastlines of two former oceános.8
Martian water is also still in the planet’s atmosphere, although so very small proportion (0.01%) which, if fully condense on the surface of Mars, it would form on a liquid film whose thickness would be approximately one-hundredth of a millimeter. Despite its scarcity, the water vapor participates in an annual cycle. Mars, atmospheric pressure is so low that the water vapor in the soil is solidified in the form of ice at the temperature of -80 ° C. When the temperature rises back above this limit the ice sublimates, turning into vapor without passing through the liquid state.
The analysis of some images show what appear to be drops of liquid water that splashed the legs of the Phoenix Mars Lander after it landed.