MARS might once have had a climate capable of supporting life, new research has concluded.
Massive canyon mountains on the Red Planet were created by vast amounts of underground water flowing close to the surface, scientists have found.
The dramatic discovery in the Valles Marineris enhances the belief that Mars could have harboured li
fe in the past. It must have had a "warm and wet" climate billions of years ago when the ridges and rift valleys, called grabens, were formed.
Dr Allan Treiman, a senior scientist at the Lunar and Planetary Institute, Arizona, said the mountains originate from fault zones – areas of multiple rock fractures – being cemented together by minerals carried during ancient groundwater flow.
Dr Treiman believes that when the fault zones formed between 3,500 and 1,800 million years ago, in an age known as the Hesperian epoch, groundwater must have flowed close to the planet's surface.
His study of images obtained from Viking, Mars Express, Mars Reconnaissance Orbiter and Mars Odyssey missions found the deposition of minerals by the water was "regionally significant".
Dr Treiman mapped the distribution of the mountain ridges and discovered that some extend many miles and are intimately associated with faults and fault zones. Some are parallel to each other while others show a criss-crossing pattern and, in places, the ridges can appear as wall-like features apparently a few miles high.
Dr Treiman said: "These erosion-resistant ridges, which can be tens of kilometres long, most likely represent cementation of the fault zones and surrounding rock by water-deposited minerals and suggest groundwater in this region flowed for long distances through major east-west-trending fault systems.
"This interpretation implies that liquid water was stable at, or near, Mars's surface when the fault zones were cemented and that chemical deposition from groundwater was regionally significant."
He said understanding groundwater flow was vital to assessing "the possibility of past and present Martian life". Dr Treiman added: "If groundwater were present at Mars's ancient surface in the Valles Marineris area, a thick permafrost layer could not have been present, which suggests a warm, wet climate when these graben-forming faults initiated and grew."
Sweeping almost 2,500 miles across the rugged landscape, the Valles Marineris is as long as the whole of Europe and dwarfs Colorado's Grand Canyon. It is more than six miles deep in places, six times the depth of the Grand Canyon, and up to 125 miles wide. The feature is so enormous it can be seen with Earth-based telescopes.
The news comes in the same month it emerged Britain would rethink its stance on not sending people into space, in what Ian Pearson, the science minister, called a "new wave" of exploration. China has started investing more in its space programme and France has called for an international manned mission to the Moon.
Nicolas Sarkozy, the French president, has called for a global programme to explore Mars, bringing together European states and space powers such as the United States and Russia.
LIE OF THE LAND ON RED PLANETKNOWN as the red planet because of its coloured appearance when seen from Earth, Mars is the fourth planet from the Sun.
It has the longest canyon network in the solar system, stretching over 3,100 miles and averaging more than three miles deep.
Mars also boasts the system's largest volcano at more than 50 times bigger than any on Earth.
It is 17 miles high and 435 miles across, but is now extinct.
Mars has a thin carbon dioxide atmosphere, a small iron core and two moons.
A Martian year takes more than twice the length of time as a year on Earth.
But a day is very similar to Earth at 24 hours and 37 minutes.
It is closer in temperature to Earth than any of the other planets in the solar system, but its weather is even more unpredictable than ours.
Temperatures reach as high as 27C in the summer but drop as low as -87C in winter.
Tornadoes five miles high can also wreak havoc as they whip across the planet's surface.
The full article contains 696 words and appears in The Scotsman newspaper.
