This image, taken by the Narrow Angle Camera (NAC), shows the double rings of an unnamed peak-ring basin. Concentric ring structures like these form during the impact that creates a basin; the number and characteristics of the rings depend on the size of the impact structure and the gravity of the planet.

This image was acquired as part of MDIS's high-resolution surface morphology base map. The surface morphology base map will cover more than 90% of Mercury's surface with an average resolution of 250 meters/pixel (0.16 miles/pixel or 820 feet/pixel). Images acquired for the surface morphology base map typically have off-vertical Sun angles (i.e., high incidence angles) and visible shadows so as to reveal clearly the topographic form of geologic features.

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. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MDIS is scheduled to acquire more than 75,000 images in support of MESSENGER's science goals.

Date acquired: July 20, 2011
Image Mission Elapsed Time (MET): 219644470
Image ID: 527930
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -17.66°
Center Longitude: 45.56° E
Resolution: 175 meters/pixel
Scale: The large double ring basin is about 172 km (107 miles) in diameter.
Incidence Angle: 65.6°
Emission Angle: 0.7°
Phase Angle: 66.1°

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.