Thursday, November 24, 2011

Topography of Mars

Color coding in this image of Mars represents differences in elevation, measured by the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor. While surface liquid water is rare and ephemeral on modern Mars, the topography of Mars reveals large, ancient valley networks and outflow channels. These are evidence that liquid water was more common and played a much more important role in Mars' past.

Image credit: NASA/JPL-Caltech

Note: The view of this map is somewhat unusual; we are looking from the north to the south. The "blue land" to the left is Acidalia Planitia (dark blue) and Chryse Planitia (light blue). The "green land" on the far left limb is Arabia Terra, while the green and yellow land to the middle right is Lunae Planum (lower right) and Xanthe Terra (upper middle right, with the large craters). The long blue and green streak in the "red land" is Valles Marineris; that leads to the various chasmata and chaotic terrains that lie near the top (southernmost) limb of the planet. The green "dogleg" at the bottom right is Echus Chasma (far right) and Kasei Valles (middle right), which flowed into Chryse Planitia.

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