Posted by tourdemars to Life on Mars at June 30, 2006 02:20 PM

A shiny coating found on rocks in many of Earth's deserts suggest a new way to search for signs of life on Mars, scientists said today. The coating, known as desert varnish, binds traces of DNA, amino acids and other organic compounds to desert rocks over the eons. Desert varnish has been found in the Atacama desert in Chile, the Mojave desert in California and Canyonlands National Park in Utah. Prehistoric people carved the varnish away, revealing lighter-colored rock underneat to create petroglyphs. The logic is simple: Samples of Martian desert varnish could perhaps show whether there has been life on Mars at any time during its 4.5-billion-year history.