This image, about 2 millimeters across, from NASA's Phoenix Mars Lander's Optical Microscope shows particles collected on a magnetic surface inside the lander's microscope. The particles are larger grains seen within the fine orange dust that covers most of the ground at Phoenix's landing site. The particles vary in color, but are of similar size, about one-tenth of a millimeter. Credit: NASA/JPL-Caltech/University of Arizona/Imperial College London
