What is the evidence for water on Mars?
The Viking Orbiter photographed much of the surface of Mars and revealed many areas covered by channels that could not have been produced by lava (right image). These dendritic channels become more complex on downward slopes just as water channels appear on Earth. Fragments of martian rock recovered from Antarctic meteorites show considerable water locked up in the crystals indicating that there was water on Mars at one time. The best dating that can be done from counts of impact craters on these ‘stream beds’ suggests running water about 3-4 billion years ago in the so-called ‘Noachen period’. There may be considerable sub-surface water based on the ‘mud flows’ seen in some impact craters. Also, the permanent part of the southern ice cap is believed to be water ice. Here is the text from a NASA report by Dr. Vivien Gornitz summarizing the evidence. Water on Mars By Vivien Gornitz On July 4, 1997, Mars Pathfinder touched down on a rocky, rusty, wind-blown surface, reminiscent of terres
