This dramatic NAC image was acquired about 56 minutes prior to MESSENGER’s
closest approach during the mission’s recent Mercury flyby, as the
spacecraft approached the planet's illuminated crescent (PIA11247).
Prominent toward the horizon in this view of newly imaged terrain is a
long cliff face. A small impact crater (about 30 kilometers, or 19 miles,
in diameter) overlies this lengthy scarp. The scarp extends for over 400
kilometers (250 miles) and likely represents a sign of aging unique to
Mercury among the planets in the Solar System. As time passes, the
interior of a planet cools. However, the relative size of Mercury's
central metallic core is larger than that of the other planets and hence
has significantly affected the planet’s geologic evolution. The numerous
long scarps on Mercury are believed to be the surface expression of faults
formed in the rocks of Mercury's crust as the interior of the planet
cooled and contracted. This contraction compressed the surface and thrust
some sections of crust over others, creating long curving cliffs like the
one shown here.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766454
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 420 meters/pixel (0.26 miles/pixel) on the right side of the image
Scale: The small crater superimposed on the long cliff is about 30 kilometers (19 miles) in diameter
Spacecraft Altitude: 16,500 kilometers (10,300 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.