A barren Mars packs a surprise underground beneath its soil – massive deposits of water ice – which if melted will create enough water to fill the Lake Superior – the largest of the Great Lakes in North America.
The revelation was made by researchers at University of Texas, Austin, by compiling data from NASA’s Mars Reconnaissance Orbiter – specifically the data collected by ground-penetrating Shallow Radar (SHARAD) instrument – during more than 600 overhead passes made by the orbiter.
According to findings part of Utopia Planitia region on Mars, in the mid-northern latitudes has extensive deposits of ice composed of 50 to 85 per cent water ice, mixed with dust or larger rocky particles. The deposit ranges in thickness from about 80 metres to about 170 metres.
Utopia Planitia is a basin with a diameter of about 3,300 kilometres, resulting from a major impact early in Mars’ history and subsequently filled.
According to researchers at the latitude of this deposit – about halfway from the equator to the pole – water ice cannot persist on the surface of Mars today because it sublimes into water vapour in the planet’s thin, dry atmosphere. One of the reasons why the water ice is still present underground at this location is that it is shielded from the atmosphere by a soil covering estimated to be one to 10 metres thick.
Scientists believe that this deposit would have formed because of accumulation of snow from snowfall during a period in Mars history when the planet’s axis was more tilted than it is today. Mars accumulates large amounts of water ice at the poles. In cycles lasting about 120,000 years, the tilt varies to nearly twice that much, heating the poles and driving ice to middle latitudes.
Climate modeling and previous findings of buried, mid-latitude ice indicate that frozen water accumulates away from the poles during high-tilt periods. The newly surveyed ice deposit spans latitudes from 39 to 49 degrees within the plains. It represents less than one per cent of all known water ice on Mars, but it more than doubles the volume of thick, buried ice sheets known in the northern plains.
Researchers say that the ice deposits close to the surface of Mars could prove to be a vital resource for humans once they reach more because it will be much more accessible than most water ice on Mars. This is because the location of these particular ice deposits are at a relatively low latitude and lies in a flat, smooth area where landing a spacecraft would be easier than at some of the other areas with buried ice.
The Utopian water is all frozen now. If there were a melted layer – which would be significant for possibility of life on Mars – it would have been evident in the radar scans.
The study was published in the journal Geophysical Research Letters.