From Earth to Mars
This view of grains from a sand dune near Christmas Lake, Ore., was taken by a test version of the Mars Hand Lens Imager (MAHLI) camera on Curiosity, NASA's Mars Science Laboratory, which is slated to launch in fall 2011. The image includes three manufactured spheres; each is a 2-millimeter-diameter (0.08-inch-diameter) ball bearing, placed to provide an independent measure of the image scale. Reflected in each sphere is the glow from the camera's four white LEDs (light-emitting diodes).
This image has a resolution of 15.4 microns per pixel, which is about twice as high as the camera resolution on Mars Rovers Spirit and Opportunity. The view covers an area about 1 inch, or 2.5 centimeters, across.
Geologists can examine an image like this for information about the composition of the sand. In this case, the largest white grains are pumice fragments and the dark black and gray grains are fragments of basalt. Nearly transparent, slightly yellow crystals are feldspars. The crystals and pumice were erupted by Mount Mazama in its terminal explosion about 7,700 years ago; the volcano is known today as Crater Lake.
Image Credit: NASA/JPL-Caltech/Malin Space Science Systems