Sand Dunes Thawing on Mars
Explanation:
What are these strange shapes on Mars?
Defrosting sand dunes.
As spring dawned on the Northern Hemisphere of Mars,
dunes of sand near the pole, as
pictured here in late May
by ESA's
ExoMars Trace Gas Orbiter, began to thaw.
The carbon dioxide
and
water ice actually
sublime
in the thin atmosphere directly to gas.
Thinner regions of ice typically
defrost
first revealing sand whose darkness soaks in sunlight and
accelerates the thaw.
The process might even involve
sandy jets exploding
through the thinning ice.
By summer,
spots will expand to encompass the entire dunes.
The
Martian North Pole
is ringed by many similar fields of
barchan sand dunes,
whose strange, smooth arcs are shaped by persistent
Martian winds.
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Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
