![]() The THEMIS infrared camera provides an excellent regional view of Mars - these images cover an area 32 kilometers (~20 miles) by approximately 50 kilometers (~30 miles) at a resolution of 100 meters per picture element ('pixel'). Many knobs and hills, including the 'face' have rocky (warm at night) material on their slopes and ridges. Some craters have cold (dark) material on their floors in the night IR image, indicating that fine-grained material is accumulating within the craters. The circular rims and eject of many of the craters in this region are warm at night, showing that rocks are still present on the steep walls inside the craters and in the ejecta material that was blasted out when the craters formed. Fine grained dust and sand cools of more rapidly at night. The nighttime temperature differences are due primarily to differences in the abundance of rocky materials that retain their heat at night and stay warm. ![]() ![]() The temperatures at night vary from approximately -90 deg C (darkest) to -75 deg C (warmest). At night many of the hills and knobs in this region are difficult to detect because the effects of heating and shadowing on the slopes are no longer present. The temperature in the daytime scene ranges from -50 deg C (darkest) to -15 deg C (brightest). This knob can be seen in the daytime image because of the temperature differences between the sunlit (warm and bright) and shadowed (cold and dark) slopes. The 'face on Mars' is located in the northern plains of Mars near 40deg N, 10deg W (350 deg E). Both images are of THEMIS's 9th IR band (12.57 microns), and they have been geometrically projected for image registration. 24, 2002 the daytime image was originally released on July 24, 2002. The nighttime THEMIS IR image was acquired on Oct. This pair of THEMIS infrared images shows the so-called 'face on Mars' landform viewed during both the day and night. ![]()
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