NASA Mars Picture of the Day: Mid-Latitude Gullies 03-17-2004

Mars Global Surveyor Mars Orbiter Camera
MGS MOC Release No. MOC2-668, 17 March 2004

NASA/JPL/Malin Space Science Systems

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)
image shows gullies in the wall of a crater
near 39.1°S, 200.7°W. Discussion among Mars scientists
as to how martian middle-
and polar-latitude gullies formed continues to this day. They
were first observed in MGS MOC images and
reported in June 2000. Most investigators agree
that gullies, such as those shown here, were formed by running water,
but disagree on whether the liquid came from snowmelt, groundwater,
or melting ground ice. Still others argue that the fluid was
carbon dioxide, and a few suggest that the gullies formed “dry”–that
is, by landsliding processes involving no liquid or gas.
This January 2004 MOC full-resolution (1.5 m/pixel; 5 ft./pixel) image is
illuminated by sunlight from the upper left. The 300 m scale bar
is approximately 984 ft. long.

Malin Space Science Systems and the California Institute of Technology
built the MOC using spare hardware from the Mars Observer mission.
MSSS operates the camera from its facilities in San Diego, California.
The Jet Propulsion Laboratory’s Mars Surveyor Operations Project
operates the Mars Global Surveyor spacecraft with its industrial
partner, Lockheed Martin Astronautics, from facilities in Pasadena,
California and Denver, Colorado.