A Tale of Two Craters
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A Tale of Two Craters

September 12, 2013
Date acquired: July 3, 2013 Image Mission Elapsed Time (MET): 15164506 Image ID: 4372034 Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) Center Latitude: 33.8° Center Longitude: 3.5° E Resolution: 31 meters/pixel Scale: The top-left crater is approximately 18 km (11.2 mi.) in north–south diameter Incidence Angle: 75.3° Emission Angle: 53.9° Phase Angle: 129.2° North is down in this image. Of Interest: Approximately 27% of Mercury's surface is classified as "smooth plains," the majority of which are interpreted to be volcanic in origin. One of the characteristics of volcanic resurfacing is the infilling by lava of pre-existing craters. In some cases, volcanism partially covers a crater, leaving the original rim visible. Often, however, lava will completely bury a crater, and only subsequent tectonic deformation (through the formation of wrinkle ridges) shows us the location of these buried—or ghost—craters. This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week. 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. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

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