Planetary scientists commonly compare and contrast the geologic features found on different planetary bodies, to learn about the similar processes that operated throughout the Solar System and to understand how each planet is different and unique. This figure, recently published in Science magazine, shows wrinkle-ridge rings on both Mercury (upper image) and Mars (lower image) that look quite similar. Wrinkle ridges arrayed in such a ring are interpreted to trace the rim of an impact crater that was nearly or completely flooded by lavas prior to ridge formation. Wrinkle ridges are created by forces that compress the crust horizontally. A buried crater rim can concentrate the near-surface forces and cause the wrinkle ridges to form a ring. The presence of wrinkle-ridge rings is thus good evidence that volcanism helped to shape the surfaces of both Mars and Mercury.

Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): A: 108826972
Instrument: A: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Mars Image: B: Mars Express High-Resolution Stereo Camera nadir image h2660_0001

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.