PIA15459: Uncovering a Dark Past

Uncovering a Dark Past


Impact craters serve as probes into a planet's subsurface, excavating and exposing material from depth that would be otherwise unobservable. Thus the study of impact crater deposits can help to elucidate the geological history of the target region. In this image, the crater Sher-Gil has exposed low-reflectance material , particularly in its eastern wall and at two concentrated points on the north and south rim. Younger, bright features called hollows dot the dark parts of the crater.

This image was acquired as part of MDIS's high-resolution stereo base map. The stereo base map is used in combination with the surface morphology base map to create high-resolution stereo views of Mercury's surface, with an average resolution of 250 meters/pixel (0.16 miles/pixel or 820 feet/pixel) or better. During MESSENGER's one-year mission, the surface morphology base map is acquired during the first 176 days, and the second 176 days are used to acquire the complementary stereo base map, which includes the image here.

Date acquired: December 01, 2011
Image Mission Elapsed Time (MET): 231267850
Image ID: 1082997
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -45.06°
Center Longitude: 135.3° E
Resolution: 102 meters/pixel
Scale: Sher-Gil crater is about 76 km (47 mi.) in diameter
Incidence Angle: 59.6°
Emission Angle: 15.9°
Phase Angle: 65.0°

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. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MDIS is scheduled to acquire more than 75,000 images in support of MESSENGER's science goals.

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 .

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
Acquisition Date
Release Date 2012-03-01
Date in Caption 2011-12-01
Image Credit NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Source photojournal.jpl.nasa.gov/catalog/PIA15459
Identifier PIA15459