MGS MOC Release No. MOC2-577, 17 December 2003

This September 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows six circular features, three of which exhibit concentric, or "bullseye," patterns within them. Each circular feature is the remains of a partly-buried, partly-eroded, and partly-filled meteor impact crater. These occur in northeastern Arabia Terra. Areas such as this, located near the middle latitudes of Mars, commonly have a "scabby" or roughened appearance. The cause of this "terrain roughening" texture is unknown, although some scientists have speculated that it might result from the erosion and removal (by way of sublimation) of ground ice. This idea remains highly speculative. These features are located near 28.4°N, 317.5°W. The image covers an area 3 km (1.9 mi) wide; sunlight illuminates the scene from the lower left.