Free Astronomy Magazine March-April 2019

A s Opportunity crept farther into Endurance Crater, the dune field on the crater floor appeared even more dramatic, as seen in this false-color image, that highlights the reddish-colored dust present throughout the scene. In this image, sinuous tendrils of sand less than 3.3 feet (1 meter) high extend from the main dune field towards the rover. [NASA/JPL-Caltech/Cornell] T he small spherules on the Martian surface in this close-up image are near Fram Crater, visited by Opportunity dur- ing April 2004. The area shown is 1.2 inches (3 cen- timeters) across. The view comes from the microscopic imager on Opportunity’s ro- botic arm, with color infor- mation added from the rover’s panoramic camera. These are examples of the mineral concretions nick- named “blueberries.” Op- portunity’s investigation of the hematite-rich concre- tions during the rover’s three-month prime mission in early 2004 provided evi- dence of a watery ancient environment. [NASA/JPL- Caltech/Cornell/USGS]