In both the optical navigation images (PIA11244) and the full-planet Wide Angle Camera (WAC) approach frame (PIA11247), a bright feature is clearly visible in the northern portion of the crescent-shaped Mercury. This NAC image resolves details of this bright feature, showing that it surrounds a small crater about 30 kilometers (19 miles) in diameter, seen nearly edge-on. Presumably, the bright material was ejected from this small crater, which apparently formed relatively recently in Mercury’s past, because Mercury’s surface materials tend to darken with time. The brilliant ejecta are so bright compared with the neighboring surface that Earth-based telescopic observations also detected this feature, despite its being associated with such a small crater.

Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766564
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 410 meters/pixel (0.25 miles/pixel) in the lower right corner of the image
Scale: The bright crater is about 30 kilometers in diameter (19 miles)
Spacecraft Altitude: 16,000 kilometers (9,900 miles)

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.