Image processing by Noel Gorelick and Jayme Harris, Arizona State University; NASA/JPL

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Thermal Emission Imaging System Captures Valles Marineris

Mars was an active and violent place during the first billion or so years of its youth. Volcanoes erupted and catastrophic floods carved channels. Over time, faulting and landslides opened up the solar system's largest canyon: Valles Marineris.

With a total length of 2,500 miles (4,000 kilometers) and a wall depth exceeding six miles (ten kilometers) in some places, this vast canyon system is long enough to span the continental United States. Now you can explore Valles Marineris in this unprecedented image, featuring a 2,200-mile (3,500-kilometer) stretch of its rugged terrain, with the control strip above.

The Thermal Emission Imaging System (THEMIS) on the Mars Odyssey orbiter captured this mosaic of 549 infrared images from an altitude of about 250 miles (400 kilometers). (Black areas are sections of the surface that have yet to be photographed.) With enough resolution to show features 330 feet (100 meters) across, THEMIS also detailed layers in the canyon walls and floors of Valles Marineris (zoom in on mid-section of image). These unmistakable layers record events and processes that occurred long before the present surface of Mars took shape.

The layers on the floor of an area called Candor Chasma (zoom in on the upper, middle section of the image) suggest several possible origins such as voluminous floods of lava, recurring falls of airborne ash, or the settling out of material in an ancient lake.

While the powerful physical forces responsible for shaping Mars's terrain may have tamed down since the red planet's early days, its surface hardly remains dormant. Wind and possibly liquid water and glaciers continue to alter the landscape of this 4.5-billion-year-old planet.


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