This NAC image was taken about 55 minutes before closest approach as the
MESSENGER spacecraft sped toward a crescent-lit planet during the
mission's second Mercury flyby (see PIA11247). The large crater in the
center of the image is near the terminator, the division between the
dayside and nightside of the planet. The low angle of the Sun near the
terminator causes the long shadows seen here, which reveal that a large
scarp or cliff bisects the crater. The crater exhibits a smooth floor
broken by slight ridges and seems to have been filled with volcanic lava
flows. In the lower left of the crater, the outline of a smaller crater
that was filled to its rim by lavas is still visible. The scarp was formed
after the large impact crater was filled with the lava flows, for if the
scarp had formed first, then the lavas would have flowed over the scarp
and buried it.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766501
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System
(MDIS)
Resolution: 420 meters/pixel (0.26 miles)
Scale: This image is about 430 kilometers (270 miles) tall
Spacecraft Altitude: 16,300 kilometers (10,100 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.