Double Crater

The surface of Mercury is dominated by the record of impact craters and basins that is has accrued over billions of years, and so it is no surprise that, occasionally, one impact crater forms within another. In this scene, the smaller crater in the bottom center of the image, some 16 km (10 miles) in diameter, is sited entirely within a larger crater, 40 km (25 miles) across. As we have seen often before, the Law of Superposition allows us to determine the sequence in which these craters formed -- the smaller one could not have survived the formation of the larger crater, and so formed second.

This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.

Date acquired: November 11, 2013
Image Mission Elapsed Time (MET): 26454699
Image ID: 5174833
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -26.32°
Center Longitude: 248.86° E
Resolution: 80 meters/pixel
Scale: The field of view in this image is about 90 km (56 mi.) across
Incidence Angle: 70.5°
Emission Angle: 4.4°
Phase Angle: 74.9°
North is to the top of the image.

Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington