Explanation:
What caused this sudden cloud of dust on Mars? An avalanche!
The first
avalanche
imaged in progress on another planet was recorded last month on
Mars by
NASA's robotic
Mars Reconnaissance Orbiter.
Visible in the
above picture, digitally rescaled, are several layers of
white ice thawing over red rock,
with darker colors toward the right indicated
Martian soil that mixed with lesser amounts of ice.
As the cliff of over 700 meters high was
thawing,
falling ice crashed down raising plumes of ice and dust so thick they cast
visible shadows.
The scarp has slopes with grades greater than 60 degrees.
The entire scene is illuminated from the upper right by the Sun.
A thaw occurs each spring in the
Northern Hemisphere of Mars, as the warming climate causes solid
carbon dioxide ice to
sublimate directly to vapor.
Studying such avalanches allows planetary geologists to better understand
soil configurations on Mars.
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