NASA/JPL/Malin Space Science Systems
If a boulder rolls down a slope on an uninhabited planet, does it make a sound? While we do not know the sound made by a boulder rolling down a slope in the martian region of Gordii Dorsum, we do know that it made an impression. This full-resolution Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a series of depressions made on a dust-mantled slope as a boulder rolled down it, sometime in the recent past. The boulder track is located just right of center in this picture. The boulder sits at the end of the track. This picture was acquired in May 2003; it is located near 11.2°N, 147.8°W. North is toward the lower left, sunlight illuminates the scene from the right. The picture covers an area only 810 meters (about 886 yards) across.
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.