NASA Spirit Rover's Silica Find Theorized as Sign of Life on Mars

NASA Spirit rover's discovery of silica on Mars back in 2008 is now being taken as a possible sign of life -- as in ancient microbes -- by two Arizona State researchers, according to Smithsonian magazine.

The opaline silica material deposits, shaped like heads of cauliflower, were found by Spirit inside Mars's Gusev crater. Arizona State's Steven Ruff and Jack Farmer said in December that similar silica formations were found in the El Tatio region of the Atacama Desert in Chile, a region scientists say most resembles the surface of Mars.

The researchers described their theory at December's American Geophysical Union meeting in San Francisco.

"… New observations of silica deposits produced in small discharge channels from hot springs and geysers in a high elevation geothermal field known as El Tatio in the Atacama Desert of northern Chile reveal remarkably similar features, including infrared spectral characteristics and what we describe here as micro-digitate silica structures," said the paper's abstract.

"… Our ongoing field and lab studies are intended provide a robust assessment of the biogenicity of the micro-digitate silica structures and other aspects of El Tatio silica sinter deposits and test their viability as direct analogs to similar features found among the Home Plate silica deposits on Mars." 

The Smithsonian said that while the Atacama Desert does have breathable oxygen, its dry environment mimics what Mars could have been like when it was warmer. It rains less than 100 millimeters per year there with temperatures ranging from -13 degrees to 113.

The desert also gets Mars-like ultraviolet radiation with its elevation of 13,000 feet above sea level.

The discovery of silica on Mars has confounded NASA scientists.

"These high-silica compositions are a puzzle," Albert Yen, a Curiosity science team member at NASA's Jet Propulsion Laboratory, said on NASA's website in December. "You can boost the concentration of silica either by leaching away other ingredients while leaving the silica behind, or by bringing in silica from somewhere else.

"Either of those processes involve water. If we can determine which happened, we'll learn more about other conditions in those ancient wet environments," said Yen.

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