By Nicole Willett (Mars Society Education Director)
Red Planet Pen Blog (Issue #39)
Scientists have carefully studied and tracked the history of water on the Red Planet. It is now widely accepted due to the geomorphological evidence that Mars had an ocean of liquid water billions of years ago. This ocean covered the northern hemisphere. This is indicated by the lower altitude of the surface, smoother and geologically newer surface of the northern hemisphere, as opposed to the higher altitude and the more jagged appearance of the highlands of the southern hemisphere. An ocean covering most of the northern hemisphere has consequences such as a thicker atmosphere and warmer temperatures.
It is clear by photographic evidence that volcanic activity was very active in Martian history. In close proximity to ancient volcanoes are areas of catastrophic flooding, caused when volcanic heat rapidly melted the subsurface ice. This evidence can still be seen today. (Nature6) Mars has a significant CO2 atmosphere, which would have been important to sustaining a warmer and wetter planet in the past. This thicker atmosphere could have been in place for 10 million to a billion years. Volcanism and cycling of carbonate rocks would have helped to ...