Explanation:
It's spring for the northern hemisphere of Mars and
spring on Mars usually means
dust storms.
So the dramatic brown swath of dust (top) marking the otherwise
white north polar cap in this picture of the
Red Planet is not really
surprising.
Taking advantage of the good views
of Mars currently possible
near opposition and its closest approach to planet Earth in 2010,
this sharp image shows
the evolving dust storm extending from the large dark region known as
Mare Acidalium below the polar cap.
It was recorded on February 2nd with the 1 meter telescope at
Pic Du Midi, a
mountain top
observatory in the French Pyrenees.
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