We have seen limb images of Mercury many times before, and they never fail to showcase the geological diversity (and splendor!) of the innermost planet. This time, something fills the scene with terror -- Terror Rupes, to be precise, the long, cliff-like landform visible at the center of the scene. Terror Rupes is one of Mercury's most prominent lobate scarps, and was named for HMS Terror, an eighteenth-century warship that later participated in scientific polar explorations. (For an explanation for how lobate scarps likely form, see this previous featured image.)
This image was acquired as part of MDIS's limb imaging campaign. Once per week, MDIS captures images of Mercury's limb, with an emphasis on imaging the southern hemisphere limb. These limb images provide information about Mercury's shape and complement measurements of topography made by the Mercury Laser Altimeter (MLA) of Mercury's northern hemisphere.
Date acquired: February 04, 2012
Image Mission Elapsed Time (MET): 236853865
Image ID: 1353252
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: -69.3°
Center Longitude: 96.0° E
Resolution: 2.7 kilometers/pixel
Incidence Angle: 80.3°
Emission Angle: 50.9°
Phase Angle: 114.5°
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
For information regarding the use of images, see the MESSENGER image use policy.