Heart-Shaped Mesa

The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) captured this unique view of a bright, heart-shaped mesa in the south polar region on November 26, 1999. The presence of this mesa indicates that the darker, rough terrain that surrounds it was once covered by a layer of the bright material.

If the heart looks to you like it is a pit (negative relief) rather than a mesa (positive relief), that is because there are two effects that make this a challenging object to see. Sunlight illuminates the heart from the lower left, thus the lower left wall of the heart looks bright because it is reflecting this sunlight. Some very small amounts of residual frost are seen on the slopes facing away from the sunlight (toward the lower right and toward the top). MOC images in the martian polar regions can sometimes fool the eye because a frosted slope might at first glance seem to be a sunlit slope. This picture was taken in late southern spring in a region that spends each winter and most of each spring completely buried in bright frost.