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Melting Point

Impact crater floor
Impact crater floors are commonly flat and relatively smooth, the result of the cooling and solidification of impact melt generated by the impact event itself.

Date acquired: January 25, 2015Image Mission Elapsed Time (MET): 64531185Image ID: 7861875Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)Center Latitude: 27.1°Center Longitude: 69.1° EResolution: 14.8 meters/pixelScale: The left-to-right field of view in this image is about 8 km (5 mi.) acrossIncidence Angle: 70.8°Emission Angle: 5.1°Phase Angle: 65.7° North is up in this image.Of Interest: Impact crater floors are commonly flat and relatively smooth, the result of the cooling and solidification of impact melt generated by the impact event itself. Often, the pool of impact melt cracks as it cools, a process well illustrated by the striking Abedin crater. Although not visible in the frame above, this crater also hosts cooling cracks on its floor. It also boasts numerous terraces along its inner wall, which likely formed after the impact melt solidified. Note how the fine-grained texture of the inner walls contrasts with the crater’s floor. 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. In the mission’s more than three years of orbital operations, MESSENGER has acquired over 250,000 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