Guessing the Number of Craters in this Image

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Caption:

Counting craters on Mercury is a serious job, as the density of craters on the surface of a planet can be used to indicate its age; the more craters present, the older the surface. Although this technique is commonly used on planetary bodies throughout the Solar System, crater counting on Mercury is particularly challenging. Secondary craters are formed by debris thrown out during an impact , and are often big enough to be confused with primary craters. Their inclusion in crater-counting studies, however, would skew derived age results for a surface, making it appear older than it really is, and so care must be taken when deciding which craters to count, and which to leave out.

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 05, 2012
Image Mission Elapsed Time (MET): 260592647
Image ID: 2897484
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -37.74°
Center Longitude: 194.02° E
Resolution: 117 meters/pixel
Scale: The crater just left of upper center is ~20 km (12 mi.) in diameter
Incidence Angle: 37.9°
Emission Angle: 4.6°
Phase Angle: 38.7°
North is to the right of 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. 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 acquired 88,746 images and extensive other data sets. MESSENGER is now in a year-long extended mission, during which plans call for the acquisition of more than 80,000 additional images to support MESSENGER's science goals.

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

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