Fresh evidence that there could be life on Mars has been discovered by scientists. That is because the weather on the Red Planet was significantly warmer in the recent past than previously thought, they revealed today.
The findings mean any martian life that existed then could still be living today beneath the now icy surface.
It is a major boost to the search for alien life, and supports NASA’s announcement in January that fresh plumes of methane may be from living organisms.
The latest research, by Dr Matthew Balme, of The Open University at Milton Keynes, is based on a study of landforms that were created by the melting of frozen soils.
It suggests that the last great thaw occurred “only” two million years ago – planetary scientists had generally believed that Mars was locked permafrost conditions for billions of years.
Dr Balme studied high-resolution photos taken from orbit around the Red Planet by he most powerful camera ever sent to another world – the HiRise instrument aboard NASA’s Mars Reconnaissance Orbiter.
He said: “The features of this terrain were previously interpreted to be the result of volcanic processes. The amazingly detailed images from HiRise show that the features are instead caused by the expansion and contraction of ice, and by thawing of ice-rich ground. This all suggests a very different climate to what we see today.”
All of the landforms observed are in an outflow channel, thought to have been active as recently as two to eight million years ago. Since the landforms exist within, and cut across, the pre-existing features of the channel, this suggests that they too were created within this timeframe.
The pictures show polygonal patterns, branched channels, blocky debris and other structures similar to those on Earth in areas where permafrost terrain is melting.
Dr Balme said, “These observations demonstrate not only that there was ice near the Martian equator in the last few million years, but also that the ice melted to form liquid water and then refroze.
“And this probably happened for many cycles. Given that liquid water seems to be essential for life, these kinds of environments could be a great place to look for evidence of past life on Mars.”
Earlier this month, it was announced that the site of an ancient lake on Mars has been located. HiRise has found other evidence that water flowed on the planet. Europe’s Mars Express has also spotted strong clues for running water in the past and NASA’s robot rovers have found signs on the surface.
