A New Place to Search for Life's Ancient Traces on the Red Planet

Scientists using a Mars-orbiting camera designed and operated at Arizona State University's Space Flight Facility have discovered the first evidence for deposits of chloride minerals, salts, in numerous places on Mars. These deposits, say the scientists, show where water was once abundant and may also provide evidence for the existence of former life on Mars. Salt deposits point to a lot of water, which could potentially remain standing in pools as it evaporates. For life, it's all about a habitat that endures for some time.

Over a long period of time, water flowing into a basin can concentrate the organic materials that could be well preserved in the salt. On Earth, salt has proven remarkably good at preserving organic material. For example, bacteria have been revived in the laboratory after being preserved in salt deposits for millions of years.

Bright blue marks a deposit of salt minerals in the southern highlands of in the THEMIS false-color image highlights mineral composition differences. Using THEMIS, researchers have found more than 200 such features. These deposits typically lie within topographic depressions and suggest that was much wetter long ago.

Developed at Arizona State University, THEMIS is a multi-wavelength camera that takes images in five visual bands and 10 infrared ones. At infrared wavelengths, the smallest details THEMIS can see on the martian surface are 330 feet (100 meters) wide.

The scientists found about 200 individual places in the martian southern hemisphere that show spectral characteristics consistent with chloride minerals. These salt deposits occur in the middle to low latitudes all around the planet within ancient, heavily cratered terrain.

When plotted on a global map of Mars, the chloride sites appeared only in the southern highlands, the most ancient rocks on Mars.

The scientists think the salt deposits formed mostly in the middle to late Noachian epoch, a time that researchers have dated to about 3.9 to 3.5 billion years ago. Several lines of evidence suggest then had intermittent periods of substantially wetter and warmer conditions than today's dry, frigid climate.

Looking for evidence of life on Mars, for bacteria or higher plants that existed on or other planets in the solar system, looking for cellulose in salt deposits is probably one of the best ways to go. Cellulose appears to be highly stable and more resistant to ionizing radiation than DNA. And if it is relatively resistant to harsh conditions such as those found in space, it may provide the ideal ‘paper trail’ in the search for life on other planets. But first, find the salt!

Posted by Casey Kazan.

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http://cmarchesin.blogspot.com/2008/03/new-place-to-seek-life-on-mars.html
Photo Credit: Credit: NASA/JPL/Arizona State University/University of Hawaii