Valles Marineris: The Grand Canyon of Mars

The largest canyon in the Solar System cuts a wide swath across the face of Mars . Named Valles Marineris , the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth's Grand Canyon in Arizona , USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep. The origin of the Valles Marineris remains unknown, although a leading hypothesis holds that it started as a crack billions of years ago as the planet cooled . Recently , several geologic processes have been identified in the canyon . The above mosaic was created from over 100 images of Mars taken by Viking Orbiters in the 1970s. News: Mars closest in over 50,000 years on Wednesday