Water on Mars Theory Debunked?

March 3, 2008 -- With great excitement, scientists in 2006 unveiled photographs of recently carved gullies on Mars, believing that a burst of underground water may have left its mark.

Not so, say researchers with the University of Arizona, who have been using topographical data derived from new images of Mars and running them through computer models.

Turns out the gullies bear more similarity to channels carved from dry granular debris, such as sand or gravel, said Jon Pelletier, a lead author of a paper on the findings appearing in this month's issue of Geology.

"It rules out pure liquid water," Pelletier said.

In December 2006, Michael Malin, with San Diego-based Malin Space Science Systems, and colleagues published an article in Science theorizing that bright streaks found in two Martian gullies which appeared since 1999 "suggest that liquid water flowed on the surface of Mars in the past decade."

The images, taken by Mars Global Surveyor in 2006, showed an area of Mars that had changed since the spacecraft's first photographs in 1999. The new research is based on imagery from NASA's new sharp-eyed Mars Reconnaissance Orbiter.

"I started off thinking we were going to prove it's liquid water," Pelletier said. "I was surprised."