Water on Mars raises chance of Martian life

By Maggie Fox, Health and Science Correspondent

  
WASHINGTON, June 22 (Reuters) - The discovery that liquid water may have flowed very recently on Mars -- and might even be flowing today -- greatly increases the odds that life might be found on the red planet, scientists said on Thursday. 

Researchers looking at images taken from an orbiting NASA spacecraft said they had found gullies and landslides that look very much like gullies and landslides formed by flowing water on Earth, which in turn suggests that liquid water will be found close under the frozen surface of Mars. 

``If the evidence proves true that ... there is water on Mars near the surface, it has profound implications for the possibility of life on Mars,'' Ed Weiler, associate NASA administrator for space science, told a news conference. 

The reason: this would fulfil the basic requirements needed for life, at least on Earth. 

All that is needed for life on Earth, Weiler said, is liquid water below the boiling point, the organic molecules from which living things are made, which have been spotted throughout space, and some source of energy -- from the sun or from a chemical reaction. 

``On Earth, everywhere you find water below the boiling point, you find life,'' said Bruce Jakosky, director of the centre for astrobiology at the University of Colorado in Boulder. 

In recent years, scientists have found creatures thriving around thermal vents miles (km) beneath the surface of the ocean, where no light reaches and where the pressure would instantly flatten any surface creature. 

They have found bacteria in hot springs, deep under the Earth's surface, in oil wells and even living in Arctic ice. 

The existence of such creatures, known as extremophiles, makes it possible that similar life could be found in the forbidding environment of Mars, in slushy seas on some of Jupiter's moons and elsewhere. 

Mars has all the necessary ingredients -- sunshine, organic molecules and, possibly, liquid water. ``I think it's the smoking gun that says it is liquid water and Mars meets all the requirements to support life,'' Jakosky said. 

``If the very first place we look in the universe in depth has or had life, that has profound implications,'' Weiler added. But, he stressed, ``We have not found evidence of life on Mars.'' 

Scientists also believe any Martian life would be very simple indeed -- probably no larger or more complex than a bacterium. 

The strongest evidence of life on Mars is a meteorite that fell to Earth from Mars 13,000 years ago. The potato-sized space rock attracted global attention in 1996 when NASA scientists said they had found chemical traces that could have been left by tiny bacteria. 

Scientists are still studying and debating the evidence found in the rock, which was found in Antarctica and considered fairly pristine. 

The most recent findings suggesting water flow will be subjected to similar scrutiny and debate. That is the basis of the scientific method: scientists come up with an idea or discovery and publish it so other scientists can point out flaws or come up with evidence that supports it. 

Some experts have even suggested that life originated on Mars. It is widely accepted that Mars would have been warm and wet billions of years ago before losing its protective atmosphere. 

Studies have shown bacteria can survive the conditions they would encounter in space if a big meteorite knocked a chunk of Mars off the planet and sent it spinning toward the Earth. 

17:43 06-22-00

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