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siriusmre
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SPACE.com ran a story today that featured "images of a new gully that formed [on Mars] between July 2002 and April 2005." The text of the story, though, is mostly about a re-visioning of a hypothesis floated in 2000 to explain the "gullies" or rilles unexpectedly seen on the Martian surface (with the Mars Global Surveyor) by comparing the Martian formations to those seen on the Moon. The 200 MGS imgaes prompted speculation that there might actually be liquid water just below the Martian surface.<br /><br /><font color="yellow">[Gwendolyn Bart, a graduate student in planetary sciences at the University of Arizona, who presented her findings last week at the 37th Lunar and Planetary Science Conference in Houston] and other scientists are skeptical of the finding because Mars’ temperature and pressure are so low that liquid water can only exist for short periods of time before freezing or evaporating.<br /><br /><b>"I would think that if there’s some non-water process that could form it, it would be more likely,"</b> Bart said in a telephone interview.<br /><br />Last year, Bart heard a talk by Allan Treiman, a senior scientist at the Lunar and Planetary Institute, who believes Martian gullies can be explained without resorting to explanations involving recent water. <br /><br />"It’s completely possible that there’s no water involved at all and that what we’re seeing are just dry flows of dust and sand," Treiman told SPACE.com. "You can get massive flows of material that’s completely dry and ends up having pretty much the same shape as if they were wet." [Emphasis added.]</font><br /><br />There is also another explanation that also does not require water--or any liquid, for that matter!<br /><br /><font color="yellow">Laboratory study of the way electric arcs affect surface materia</font> <div class="Discussion_UserSignature"> </div>