'Antifreeze' chemicals found on Mars could indicate signs of life

An 'antifreeze' chemical found in soil on Mars could allow pockets of life-sustaining liquid water to exist on the planet, say scientists.

Last year, Nasa's Phoenix lander made the surprise discovery of perchlorates in the Martian soil.

The chemicals, containing chlorine and oxygen, are relatively rare on Earth but abundant on Mars. They made up 1 per cent of the soil samples tested by the Nasa probe.

Scientists believe an 'antifreeze' chemical found in Martian soil could help sustain life there



Perchlorates act as an antifreeze, allowing water to remain liquid below 0C.

Scientists now believe this could have profound implications on Mars, making the existence of liquid water - and possibly life - much more likely.

Water containing certain types of dissolved perchlorates can remain liquid at temperatures of -37C.

That would allow pockets of liquid water to lie just below the Martian surface, say scientists. There is even a possibility of water sometimes flowing above ground.

An artist's rendition showing the Phoenix lander on Mars

Phoenix team member Dr Nilton Renno, from the University of Michigan, told New Scientist magazine: 'It's possible to have (liquid) almost everywhere where there is ice and the temperature goes above this threshold value - that's most of Mars.'

The discovery could explain recently formed gullies on Martian slopes that look much like water-carved features on Earth.

Perchlorate-laced water may also accumulate under glaciers and help them slide around. There are indications that very cold and stiff glaciers on the northern Martian ice cap have been moving.

Dr Renno believes perchlorate-rich water droplets might even explain mysterious bumps on Phoenix's landing legs that appeared to flow and merge.

Other scientists think they are probably bumps of ice with changing light giving the illusion of liquid-like behaviour.

Martian microbes could feed off perchlorates, as some Earth organisms do, the researchers believe.

New Scientist said highly concentrated perchlorate solutions would be unlikely to support life, 'but milder solutions could allow liquid and thus life to exist'.