Red Planet may be hiding millions of litres of water

Mars: The sand dunes on Mars may hide an unexpected secret - millions of litres of water, aIrish scientist believes.

Dr Mary Bourke of the Planetary Science Institute in Tucson, Arizona, said she has identified a surprising source of precious water on the Red Planet, something that would make a manned mission there much more attractive.

The extensive dunes that ring the north Martian pole and similar sand hills in the Southern Crater dune fields could be 40 to 70 per cent water, trapped as layer upon layer of snow.

Sand layers on top prevent the snow and water ice crystals from melting away into the thin Martian atmosphere, trapped water waiting to be discovered by astronauts should any venture there as promised in 2015.

When it comes to dunes and deserts Mars is the solar system's hands-down winner. Its northern dunes crisscross possibly the largest desert on any planet circling our sun. It also boasts the single largest dune, a 6.5-km wide, 475-metre-tall giant in the Kaiser Crater in the southern hemisphere. If even some of the Martian dunes hold water there will be plenty to toast any arriving astronauts.

"I think I have discovered evidence for ice in sand dunes on Mars," Dr Mary Bourke told visitors to the BA Festival of Science underway at Trinity College Dublin.

"This is in the frontiers of planetary science." A geography graduate of UCD, Dr Bourke completed a PhD in Australia before joining the Planetary Science Institute in Tucson.

She and other Mars enthusiasts have watched as pictures and satellite data beamed back from the planet revealed repeated signs of a watery past - but no liquid water today.

Sand dunes and snow might seem an unlikely mix but in the vast Antarctic near desert-like conditions exist where snow and ice crystals mix to form dunes.

A gritty top conceals thick layers of ice and snow underneath. "The crystals of ice are very resistant to breakdown, it is very strong and it is well preserved," Dr Bourke said yesterday.

Features found in the Victoria Valley in Antarctica began to look very similar to structures Dr Bourke saw in the Martian satellite data from the Russell Crater and other locations. These structures included overhangs, cornices and truncated dunes that didn't seem to blow away.

"There is something in the sand dunes of Mars that is sticking them together," she told the BA meeting. There is also evidence of liquid water in the past, including what could be snow-melt patterns that are repeated in Antarctica such as tensional cracks, melt water fans and sinkholes, she said. "What I am suggesting is water is freezing these sediments." She cannot date them but believes them to be "pretty recent" and possibly as recent as 100,000 years ago.

If her theory is correct then a beach spade and bucket is all any visitor will need to tap into plentiful water supplies.