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Astronomy Picture of the Day
The Dotted Dunes of Mars
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#102554
by
[z]Barbara Harris
@
06.08.2007 00:00
- nach oben -
The Dotted Dunes of Mars
Explanation:
What causes the black dots on dunes on Mars?
As spring dawned on the Northern Hemisphere of
Mars
in 2004, dunes of sand near the poles begin to defrost.
Thinner regions of ice typically thaw first
revealing sand
whose darkness soaks in sunlight and accelerates the thaw.
The process might involve
sandy jets exploding
through the thinning ice.
By summer, the
spots
expanded to encompass the entire
dunes
that were then completely thawed and dark.
The
carbon dioxide
and water ice actually
sublime
in the
thin atmosphere
directly to gas.
Taken in mid-July, the
above image
shows a field of
spotted polar dunes spanning about 3 kilometers near the Martian North Pole.
Today, the future of
Mars rovers
Spirit
and
Opportunity
remains
unknown
windy dust storms
continue to starve them of needed sunlight.
News Flash:
Phoenix Spacecraft Launches to Mars
Credit & Copyright