PIA18734: A Colossal Wreck, Boundless and Bare

A Colossal Wreck, Boundless and Bare


Two large, highly degraded impact craters dominate this view. The top one is Delacroix. The southern rim of Delacroix cuts the northern rim of Shelley, indicating that Shelley is older. Both craters are ancient, with battered rims and interiors that have suffered countless impacts and infilling with volcanic and/or ejecta material.

Shelley is named for Percy Bysshe Shelley (1792-1822), an important English Romantic poet. His poem "Ozymandias" speaks of a ruined monument in the desert: "Round the decay/Of that colossal wreck, boundless and bare/The lone and level sands stretch far away." Such a description fits Shelley crater.

This image was acquired as part of MDIS's high-resolution stereo imaging campaign. Images from the stereo imaging campaign are used in combination with the surface morphology base map or the albedo base map to create high-resolution stereo views of Mercury's surface, with an average resolution of 200 meters/pixel. Viewing the surface under the same Sun illumination conditions but from two or more viewing angles enables information about the small-scale topography of Mercury's surface to be obtained.

Date acquired: October 17, 2011
Image Mission Elapsed Time (MET): 227297821
Image ID: 894498
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -47.0°
Center Longitude: 231.7°
Resolution: 220 meters/pixel
Scale: The scene is about 230 km (143 mi.) across
Incidence Angle: 67.6°
Emission Angle: 25.9°
Phase Angle: 73.2°
North is up in this image.

Background Info:

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. During the first two years of orbital operations, MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.

For information regarding the use of images, see the MESSENGER image use policy .

Cataloging Keywords:

Name Value Additional Values
Target Mercury
Target Type Planet
Instrument Host MESSENGER
Host Type Orbiter
Instrument Mercury Dual Imaging System (MDIS)
Detector Narrow Angle Camera (NAC)
Extra Keywords Crater, Grayscale, Impact, Map, Radio, Volcano
Acquisition Date
Release Date 2014-10-03
Date in Caption 2011-10-17
Image Credit NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Source photojournal.jpl.nasa.gov/catalog/PIA18734
Identifier PIA18734