Page 45 - (DK) Eyewitness - Mars

Polar dunes

The northern polar regions are flat seas of sand swept by
the wind, and dunes can take on complex and bizarre
geometric patterns. Designs are especially spectacular in
regions where prevailing winds change directions with the
passing seasons. Dunes of the south
polar regions are much smaller,
and are usually found in
craters and ravines.

FORTUNE-COOKIE DUNES DIZZYING DUNES
So named because many The imaginary astronaut in this artist’s
A NORTHERN CHASM resemble Chinese fortune rendering tramps through sand dunes
In this photo, summertime highlights cookies, these north polar that the wind has swirled into wavy
crescent-shaped sand dunes in dunes have steep slipface ripples. The scene was inspired by
Chasma Boreale, a wide trough in the slopes that are directed to actual dune formations in Death
north polar region. Frost has retreated the upper left. This area was Valley, California, which compare to
now, revealing dark-colored sand. photographed by the Mars some types of sand dunes on Mars.
The curved side of each dune is facing Global Surveyor.
the direction in which the wind is
blowing. This side is known as the
slipface. Sand and dust pile up here
until the wind changes direction and
forms a different slipface.

RUST-COLORED PANORAMA
This painting shows a Martian desert in all its
ruddy glory, with the sky colored by fine,
suspended dust. Only a swirling dust devil or
two bring movement to this desolate scene of
rocks, dunes, and wind-blown sand.