For the month of September, MESSENGER images of the double-ring basin Rachmaninoff are being featured by the International Association of Geomorphologists (IAG) as the planetary geomorphology image of the month. The enhanced-color image shown here is one of those featured images and highlights differences in reflectance, color, and structure between the smooth plains within the basin's inner ring and the surrounding surface. MESSENGER team members have documented evidence that these interior smooth plains are products of relatively young volcanism, the youngest documented on Mercury to date. Whereas pre-MESSENGER interpretations were that volcanism on Mercury ended early in the planet's history, MESSENGER's images of Rachmaninoff reveal that some volcanism extended well beyond that time, probably into the second half of Solar System history. Visit the IAG planetary geomorphology website to read more.

Date Acquired: September 29, 2009
Instrument: Wide Angle Camera (WAC) and Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 1.0 kilometers/pixel (0.6 miles/pixel)
Scale: Rachmaninoff basin is 290 kilometers (180 miles) in diameter

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.