Study: That's Dust, Not Water on Mars

May 8 -- The prospect of a moist Mars fostering primitive life forms has excited scientific interest in exploration of the Red Planet. But a new, rival theory has emerged that tries to undermine evidence of water and leave the idea of a wet planet literally in the dust.

The Mars Global Surveyor first relayed images showing clear evidence of recently carved gullies on Mars three years ago. Since then more than 10,000 sites of mysteriously streaked gullies have been sighted.

Some have argued the patterns are the sinuous, meandering path of running water that bubbled up from beneath the planet's crust.

Others say liquid carbon dioxide bursting from the Martian crust may have formed them while still others propose that meltwater seeping from vast ice fields carved the gullies.

Now, a somewhat unpopular idea suggests the gullies are the result of nothing but wind and dry sand and silt.

The theory was proposed just over a month before NASA and European space agencies plan to launch probes to Mars that will investigate minerals on the planet and seek possible signs of life — life that most believe would depend on the presence of liquid water.

"The business of finding water on Mars has some political significance now," said Allan Treiman of the Lunar and Planetary Institute in Houston, Texas, who authored the study in the most recent issue of the Journal of Geophysical Research. "So my idea becomes unattractive."

First Glimpses

Michael Malin, principal investigator for the Mars Orbiter Camera on the Mars Global Surveyer spacecraft, was among the first to suggest in 2000 that water flows on the planet. Since scientists believe liquid water is necessary to support life, the discovery raised the exciting possibility that life exists, or recently existed on the planet.

There is little doubt that Mars was once a much wetter place some 3.5 billion years ago. High-resolution pictures of the planet show evidence for sedimentary rocks laid down by ancient lakes and shallow seas. There also appear to be ancient river valley networks snaking throughout the planet.