{"id":6114,"date":"2017-08-22T17:02:22","date_gmt":"2017-08-22T16:02:22","guid":{"rendered":"https:\/\/ounews.co\/?p=6114"},"modified":"2017-08-22T17:02:22","modified_gmt":"2017-08-22T16:02:22","slug":"snow-mars-heres-thats-possible","status":"publish","type":"post","link":"https:\/\/www.open.ac.uk\/blogs\/news\/science-mct\/space\/snow-mars-heres-thats-possible\/","title":{"rendered":"There could be snow on Mars \u2013 here\u2019s how that\u2019s possible"},"content":{"rendered":"

Given that there are ambitious plans<\/a> to colonise Mars in the near future, it is surprising how much we still have to learn about what it would be like to actually live on the planet. Take the weather, for instance. We know there are wild fluctuations in Mars\u2019s climate<\/a> \u2013 and that it is very windy and at times cloudy (though too cold and dry for rainfall). But does it snow? Might settlers on Mars be able to see the red planet turn white? A new study surprisingly suggests so.<\/p>\n

Mars is clearly cold enough for snow. It has ice \u2013 the amount of which has varied significantly over time. When its axis is tilted at only a small angle relative to its orbit, its surface is ice-free except for the polar caps. This is the situation today, when its axial tilt is 25\u2070 (similar to Earth\u2019s 23\u2070 axial tilt). However, possibly because Mars lacks a large moon to stabilise its spin<\/a>, there have been times when its spin axis was tipped over by up to 60\u2070 \u2013 allowing the polar ice caps to spread, maybe even to the extent that there was abundant ice near the equator.<\/p>\n

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NASA\u2019s Phoenix Mars Lander didn\u2019t see snow on the ground.<\/span>
\nNASA\/JPL-Caltech\/University of Arizona\/Texas A&M University<\/span><\/span><\/figcaption><\/figure>\n

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Mars emerged from its most recent ice age about 400,000 years ago. Since then, its polar caps have been small, and any ice surviving near the equator has been buried under dust<\/a>.<\/p>\n

The planet\u2019s atmosphere is of low pressure and very dry. Although it is still possible for clouds to form at an altitude of several kilometres, until now it has been generally believed that any true snowfall would not reach the ground. The clouds, resembling Earth\u2019s cirrus clouds<\/a>, are believed to form when the small amount of water vapour in the atmosphere condenses (directly from vapour to ice) onto grains of dust lofted skywards during storms.<\/p>\n