Sept. 30, 2008 -- A robotic science probe on the surface of Mars beamed a laser into the sky and made a surprising discovery: It was snowing. "Nothing like this view has ever been seen on Mars," said Jim Whiteway, of York University, Toronto, which oversees the meteorological experiments on NASA's Phoenix lander. The spacecraft is on the northern polar region of Mars assessing if conditions were suitable for life to evolve. So far, it has confirmed the existence of water-ice and provided clues that the soil contains clays which, on Earth anyway, only form in the presence of water. Scientists believe water must be available for life to take root. The snowfall detected by Phoenix was taking place 2.5 miles above the planet's surface and vaporized before reaching the ground. Phoenix's days are numbered: The sun is sinking toward the horizon, leaving the solar-power probe with less energy. By the end of October, scientists expect they won't be able to operate Phoenix's robot arm, which has been digging into the frozen ground to fetch ice and soil samples for analysis. Meanwhile, evidence that the cold, dry deserts of Mars were once warm and flush with water continues to mount. Last week, scientists announced they had found clusters of stress fractures called deformation bands in the planet's equatorial region caused by stresses in porous bedrock beneath the surface. Features of the rocks along the fractures show effects of flowing water. Related Content: Irene Klotz's blog: Free Space My Take: Phoenix Lander More than a 'Re-Do' IM Interview: Digging for Signs of Life on Mars "Groundwater often flows along fractures such as these," said Chris Okubo of the U.S. Geological Survey in Flagstaff, Ariz. "Knowing that these are deformation bands helps us understand how the underground plumbing may have worked." The bands on Mars, which were found in layered deposits within a 43-mile diameter crater, are a few miles long. They are similar to fractures found in sandstone in Utah. The bands form from either compression or stretching of underground layers of rock. On Earth, deformation bands strongly influence the movement of ground water and appear to have been similarly important on Mars, Okubo and colleagues report in this month's Geological Society of America Bulletin. The work was based on images returned by the Mars Reconnaissance Orbiter. Related Links: |
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