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August 29, 2012
Date acquired: May 26, 2012 Image Mission Elapsed Time (MET): 246558946 Image ID: 1900095 Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) Center Latitude: -6.30° Center Longitude: 259.0° E Resolution: 198 meters/pixel Scale: The larger crater is about 51 km (31 miles) in diameter Incidence Angle: 79.2° Emission Angle: 51.2° Phase Angle: 130.5° Of Interest: This NAC image features a crater superimposed on a larger crater. Based on the law of superposition, it is apparent that the crater with the central peak is younger than the larger crater because it has destroyed part of the rim of the larger crater. Based on the same principle we can conclude that the scarp is also younger than the larger crater; the scarp cuts across the rim and floor of the larger crater meaning that the larger crater came before the scarp. More analysis would be needed to determine the relative age relationship between the central-peak crater and the scarp. Does the scarp modify the central-peak crater's ejecta, or does the ejecta cover the scarp? This image was acquired as part of MDIS's high-incidence-angle base map. The high-incidence-angle base map is a major mapping activity in MESSENGER's extended mission and complements the surface morphology base map of MESSENGER's primary mission that was acquired under generally more moderate incidence angles. High incidence angles, achieved when the Sun is near the horizon, result in long shadows that accentuate the small-scale topography of geologic features. The high-incidence-angle base map is being acquired with an average resolution of 200 meters/pixel. 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, MESSENGER acquired 88,746 images and extensive other data sets. MESSENGER is now in a yearlong extended mission, during which plans call for the acquisition of more than 80,000 additional images to support MESSENGER's science goals. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

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