Dry Ice Pits on Mars
Explanation:
Part of Mars is defrosting.
Around the
South Pole of Mars, toward the end of every Martian summer,
the warm weather causes a section of the vast carbon-dioxide ice cap to evaporate.
Pits begin to
appear and expand where the carbon dioxide dry
ice sublimates directly into gas.
These ice sheet pits may appear to be lined with gold, but the precise composition
of the dust that highlights the pit
walls actually remains unknown.
The
circular depressions toward the image center measure
about 60 meters across.
The
HiRISE camera aboard the Mars-orbiting
Mars Reconnaissance Orbiter captured the
above image in late July.
In the next few months, as Mars continues its
journey around the
Sun, colder seasons will prevail, and the thin air will turn chilly enough not
only to stop the
defrosting but once again freeze out more layers of
solid carbon dioxide.
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.
