Spring Thaw in Northwestern Planum Australe
Planum Australe--the Plains of the South. Patchy frost lingers late into Martian spring in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle view from November 25, 1999. Spring would give way to summer in only 1 month, on December 25, 1999. The surfaces underneath the frost have different properties--some get warmer while others stay cold--thus causing frost to linger on colder surfaces and sublime away from warmer surfaces, leaving the dazzling, almost psychedelic pattern seen at the center of this image. Circular features in this view are old craters formed by meteor impact. The brightest patches within most of these circles are fields of sand dunes covered by frost. The center of this scene is near 78°S, 135°W; north is toward the upper right. Illumination is from the upper left. The image covers an area 110 km (68 mi) across by 590 km (367 mi) down. This is a color composite of MOC wide angle camera images M09-06029 (red) and M09-06030 (blue). To see what the raw MOC image data look like, visit the newest data releases (for Mission Subphases M07 - M12, covering September 1999 through February 2000) in the MOC GALLERY.