The Enigma of the Martian Soil

Mars has a fine reddish soil that offers many clues to the presence of water and whether life exists or has existed in the past. In his Perspective, Banin discusses what has been learned about martian soil from past missions to the Red Planet. Increasing evidence suggests that chemical processes involving water, weathered martian rocks and formed the fine soil. The chemical and mineralogical nature of the soil is unique and several formation mechanisms that may explain this have been proposed. Soils in the Atacama Desert in Chile, one of the driest regions on Earth, may offer valuable information on Mars-like soils. Successfully understanding these soils, however, may require protecting this fragile ecosystem from human contamination.