![]() Supporting this controversial theory is the northern martian surface being less heavily cratered than in the southern hemisphere, as well as shoreline-like geographic features, and the northern plains being lower than in the southern hemisphere, just like the ocean basins back here on Earth. The image opposite shows an area of the Vastitas Borealis encircling the North Pole (left), with the large crater situated top right being the Korolev Crater, which is 53 miles (85 km) wide.Īccording to the Mars ocean hypothesis, it has a 4.1–3.8 billion-year-old southern shoreline that runs the length of Mars, except through the 4,000 km wide Tharsis volcanic region, and is therefore seen as being a good location to search for water-related sedimentary microbial life. Vastitas Borealis (“northern waste”), the largest lowland region on Mars, lies 2.5 to 3.1 miles (4–5kms) below the mean planetary elevation and surrounds the planet’s north polar region. This translates into a volume of about 1.6 million km³ of ice, in comparison to the volume of ice in the Greenland ice sheet, for instance, which is about 2.85 million km³ of ice. The north polar ice cap shown in the image, on the other hand, spans about 600 miles (1,000 km) and has an average total thickness of about 1.2 miles (2 km). Copious amounts of water are then released when it sublimes in the Martian summer, forming vast cirrus clouds in the process. The south polar cap usually spans about 217 miles (350 km) with a total thickness of about 1.8 miles (3 km) and contains about 25%-30% of the planet’s atmosphere in the form of frozen carbon dioxide. During the northern pole’s winter, it also accumulates a thin layer of frozen carbon dioxide about one meter thick, while at the southern cap it has a permanent dry ice covering around 8 meters thick. Image Credit: Getty Images/Stocktrek Imagesįor a relatively dry planet, Mars sports two very impressive polar ice caps, both of which contain huge amounts of primarily water ice.
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