Northern Polar Spring in IR

After the Odyssey spacecraft had completed a full Mars year of observations of the red planet Image of the Day looked back over this first mars year. Focus was on four themes: 1) the poles - with the seasonal changes seen in the retreatand expansion of the caps; 2) craters - with a variety of morphologies relating to impact materials and later alteration, both infilling and exhumation; 3) channels - the clues to liquid surface flow; and 4) volcanic flow features. While some images have helped answer questions about the history of Mars, many have raised new questions that are still being investigated as Odyssey continues collecting data as it orbits Mars.
Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark.
This image was collected October 19, 2002 during the northern spring season. The top half of this daytime IR image shows a portion of the North Polar sand sea and the north polar cap.