Visible in this image are curving ridges, some of which form circular outlines. One is in the left corner, and several larger ones are arranged vertically down the center-right part of the image. These circular features mark the rims of "ghost craters" -- impact craters that were subsequently buried by the voluminous volcanic lavas that form the plains in this part of Mercury. No doubt some craters were buried completely and now are entirely hidden, whereas others reveal their presence by the ridges that formed when the volcanic cover sagged over the crater rims or in response to modest horizontal contraction of the region.
This image was collected during the spacecraft's commissioning phase, shortly after entering orbit around Mercury. The image was binned on the spacecraft from its original 1024 x 1024 pixel size to 256 x 256. Binning helps to reduce the amount of data that must be stored on the spacecraft's solid-state recorder and downlinked across interplanetary space from MESSENGER to the Deep Space Network on Earth. The image here has been placed into a map projection with north at the top.
On March 17, 2011 (March 18, 2011, UTC), MESSENGER became the first spacecraft ever to orbit the planet Mercury. The mission is currently in its commissioning phase, during which spacecraft and instrument performance are verified through a series of specially designed checkout activities. In the course of the one-year primary mission, the spacecraft's seven scientific instruments and radio science investigation will unravel the history and evolution of the Solar System's innermost planet. Visit the Why Mercury? section of this website to learn more about the science questions that the MESSENGER mission has set out to answer.
Date acquired: March 29, 2011
Image Mission Elapsed Time (MET): 209895822
Image ID: 65370
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 12 (828 nanometers)
Center Latitude: 76.6°
Center Longitude: 51.8° E
Resolution: 393 meters/pixel
Scale: The edges of the image are about 100 km (62 mi.) long.
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.