Discover the cosmos! Each day a different image or photograph of
our fascinating universe is featured, along with a brief
explanation written by a professional astronomer. 2007 July 1
Explanation: Vertical cliffs of nearly two kilometers occur near
the North Pole of Mars. Also visible in the above image of the
Martian North Polar Cap are red areas of rock and sand, white
areas of ice, and dark areas of unknown composition but
hypothesized to be volcanic ash. The cliffs are thought to
border volcanic caldera. Although the sheer drop of the Martian
cliffs is extreme, the drop is not as deep as other areas in our
Solar System, including the 3.4-kilometer depth of Colca Canyon
on Earth and the 20 kilometer depth of Verona Rupes on Uranus'
moon Miranda. The above image, digitally reconstructed into a
perspective view, was taken by the High Resolution Stereo Camera
on board the ESA's robotic Mars Express spacecraft currently
orbiting Mars. Authors & editors: Jerry Bonnell (USRA) NASA
Official: Phillip Newman Specif