The image shown here was acquired at 24 m/pixel, the highest resolution that has been obtained for any of Mercury's shadowed polar craters!
The top left panel shows a view of an unnamed crater in Mercury's north polar region, with the crater rim outlined in pink and the edge of the 24-meter/pixel, low-altitude broadband MDIS image in green. In the large bottom panel, a different stretch has been applied to the same MDIS broadband image, revealing details of the shadowed surface inside the crater. In particular, as highlighted with yellow arrows in the top right panel, the image reveals a region inside the crater that has a lower reflectance. The edge of the low-reflectance region has a sharp and well-defined boundary, even as imaged at this highest resolution of 24 m/pixel. The sharp boundary suggests that the low-reflectance material is sufficiently young to have preserved a sharp boundary against lateral mixing by impact craters. The sharp boundary matches the location predicted by temperature models for the stability of a surficial layer of volatile, organic-rich material tens of centimeters thick that overlies a thicker layer of water ice.
These images were discussed at a press event on Monday at the Lunar and Planetary Science Conference. Visit the press event website to learn more!
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 2 (700 nanometers)
Scale: This unnamed crater, outlined in pink, has a diameter of 18 km (11 miles)
Crater Center Latitude: 80.30°
Crater Center Longitude: 293.47° E
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. During the first two years of orbital operations, 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.