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The surface of Mercury is dominated by impact craters, so it is not surprising that every so often one crater forms atop another. In this image, a small crater formed close to the southern margin of Mercury's northern volcanic plains, before being superposed by a slightly larger and deeper crater. This second impact removed over a third of the smaller, pre-existing crater. Yet both craters show evidence of post-formation modification, notably where their walls meet their floors. For example, a hill lies at the base of the right-hand-side wall of the larger crater. This is likely a landslide deposit that formed when material slumped off the wall.
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: July 10, 2014
Image Mission Elapsed Time (MET): 47351839
Image ID: 6659618
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 52.3°
Center Longitude: 31.6° E
Resolution: 22 meters/pixel
Scale: The crater at center-right is approximately 10 km (6.2 miles) across
Incidence Angle: 54.1°
Emission Angle: 28.3°
Phase Angle: 45.2°
Orientation: North is to the right in this image.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This small, bright crater is located in the northern plains of Mercury, southeast of the crater Stieglitz. Though it is one of many craters in the 2-5 km size range in this image, most of the others are clearly members of crater chains, created in quick succession during secondary impacts. The crater in the western portion of the image stands out from its surroundings both due to its morphology and its freshness.
This image was acquired as part of MDIS's minimum-phase-angle color campaign. Near the north polar region, the incidence angle (measured from the vertical) is always fairly high because the Sun is low on the horizon. The minimum-phase-angle color campaign acquires images under conditions that minimize the shadows in an image by viewing the surface as nearly as possible from the same direction as the Sun's illumination, which minimizes the phase angle. Images are acquired through five of the WAC's narrow-band color filters, for regions north of 60° N, at an average resolution of 500 meters/pixel. The minimum-phase-angle color campaign began in March 2013.
Date acquired: July 04, 2014
Image Mission Elapsed Time (MET): 46773193, 46773184, 46773190
Image ID: 6618773, 6618770, 6618772
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: 68.82°
Center Longitude: 71.79° E
Resolution: 273 meters/pixel
Scale: This image is roughly 225 km (140 mi.) from corner to corner.
Incidence Angle: 73.9°
Emission Angle: 45.8°
Phase Angle: 28.0°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Today's image features a small, simple impact crater on Mercury's northern plains. The superimposed track is a set of altimetry measurements by the Mercury Laser Altimeter (MLA) that resolves the bowl-shaped morphology characteristic of simple craters. This morphology is evident in the topographic profile on the right of this image that displays how the crater's depth changes from point A to point B.
Instrument: Mercury Laser Altimeter (MLA)
MLA Track: MLASCIRDRAPLFN1112211457
Crater's Center Latitude: 78.1°
Crater's Center Longitude: 327.5° E
Scale: The crater has a diameter of 4.53 km (2.81 miles)
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Rikyü is an impact crater named for Sen no Rikyü, the master who was central in the development of the Japanese tea ceremony. Rikyü sits in Mercury's northern plains and is expected to host water ice because of its persistently shadowed interior and radar-bright signature. Today's image features a northwestern segment of the crater wall, where a 4.1 km-wide simple crater has resulted from an impact on Rikyü's rim. This high-resolution image also provides a fantastic view of the tiny craters that mark the crater's wall.
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: August 04, 2012
Image Mission Elapsed Time (MET): 252610116
Image ID: 2330144
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 80.17°
Center Longitude: 335.4° E
Resolution: 13 meters/pixel
Scale: The simple crater in the lower left corner is approximately 4.1 km wide (2.5 miles)
Incidence Angle: 82.8°
Emission Angle: 44.8°
Phase Angle: 127.6°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This image is one of the highest resolution images taken by the MESSENGER spacecraft to date. It features a field of secondary craters in Mercury's northern smooth plains. Secondary craters are formed by the re-impact of debris strewn from a larger crater. The largest secondary craters in this image are roughly a few hundred meters across. If you look closely, you can see some small craters that are only tens of meters across. All of these craters are simple craters.
This image was acquired as part of the MDIS low-altitude imaging campaign. During MESSENGER's second extended mission, the spacecraft makes a progressively closer approach to Mercury's surface than at any previous point in the mission, enabling the acquisition of high-spatial-resolution data. For spacecraft altitudes below 350 kilometers, NAC images are acquired with pixel scales ranging from 20 meters to as little as 2 meters.
On 25 July 2014, MESSENGER moved closer to Mercury than any spacecraft has before, dropping to an altitude of 100 kilometers (60 miles) above the planet's surface. By 19 August 2014, the minimum altitude will be cut in half, to only 50 kilometers (31 miles)! MESSENGER will execute three more orbit-correction maneuvers in order to delay the end of mission to late March 2015. For more details on this event, read this news story.
Date acquired: June 11, 2014
Image Mission Elapsed Time (MET): 44779109
Image ID: 6477542
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 69.84°
Center Longitude: 48.47° E
Resolution: 2.9 meters/pixel
Scale: This image is about 3 km (1.8 miles) across.
Incidence Angle: 79.4°
Emission Angle: 0.1°
Phase Angle: 79.6°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Today's image of the day features a striking boundary of smooth and rough terrain near Mercury's north pole. This rugged wall of mountains would create quite a staggering view for an adventurer (or a rover) after crossing the expansive northern plains.
This image was acquired as part of MDIS's minimum-phase-angle color campaign. Near the north polar region, the incidence angle (measured from the vertical) is always fairly high because the Sun is low on the horizon. The minimum-phase-angle color campaign acquires images under conditions that minimize the shadows in an image by viewing the surface as nearly as possible from the same direction as the Sun's illumination, which minimizes the phase angle. Images are acquired through five of the WAC's narrow-band color filters, for regions north of 60° N, at an average resolution of 500 meters/pixel. The minimum-phase-angle color campaign began in March 2013.
Date acquired: April 15, 2014
Image Mission Elapsed Time (MET): 39881820, 39881827, 39881817
Image ID: 6129196, 6129198, 6129195
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: 81.78°
Center Longitude: 163.9° E
Resolution: 225 meters/pixel
Scale: The boundary of smooth and rough terrain is approximately 130 km (81 mi.) long in this image.
Incidence Angle: 82.8°
Emission Angle: 54.7°
Phase Angle: 28.0°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Today's image features several rolling hills within the northern plains of Mercury. Though covered by smooth plains material, these hills are associated with the rim of an unnamed buried crater. At this high resolution, many small craters can be seen dotting the landscape, some as small as ~20-30 m (65-100 ft) in diameter.
This image was acquired as part of the MDIS low-altitude imaging campaign. During MESSENGER's second extended mission, the spacecraft makes a progressively closer approach to Mercury's surface than at any previous point in the mission, enabling the acquisition of high-spatial-resolution data. For spacecraft altitudes below 350 kilometers, NAC images are acquired with pixel scales ranging from 20 meters to as little as 2 meters.
Date acquired: April 04, 2014
Image Mission Elapsed Time (MET): 38930993
Image ID: 6061617
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 81.67°
Center Longitude: 234.2° E
Resolution: 16 meters/pixel
Scale: This image is about 9 km (5.6 mi) across.
Incidence Angle: 81.9°
Emission Angle: 21.9°
Phase Angle: 82.3°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
The large crater at the center-left of today's image is Liang Kai. Liang Kai (the crater) is about 140 km in diameter and is fairly old. Its walls and rim have been substantially eroded, and its interior has been filled with a flat expanse of plains material.
Liang Kai (the human) was a painter of China's Southern Song Dynasty who lived from about 1140 to 1210 CE. He painted with an abbreviated approach, employing the minimal number of brushstrokes needed to evoke his subjects. Liang Kai was sometimes called "Madman Liang." One of his famous paintings is of a celestial being walking in a drunken stupor.
At the top edge of the image can be seen the terraced walls and bright central peaks of Gainsborough, named for an English painter.
This image was acquired as part of MDIS's high-resolution albedo base map. The best images for discerning variations in albedo, or brightness, on the surface are acquired when the Sun is overhead, so these images typically are taken at low incidence angles. The albedo base map covers Mercury's surface at an average resolution of 200 meters/pixel.
Date acquired: June 11, 2012
Image Mission Elapsed Time (MET): 247903483
Image ID: 1996320
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -39.3°
Center Longitude: 177.5° E
Resolution: 264 meters/pixel
Scale: The image is about 270 km (167 mi.) wide
Incidence Angle: 39.4°
Emission Angle: 35.8°
Phase Angle: 75.2°
North is toward the top of the image.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
In this image, we see a portion of a wrinkle ridge to the north of Gauguin crater, high in Mercury's northern volcanic plains. Wrinkle ridges are common on Mercury, but when imaged under high resolutions we get a more detailed view of these structures than before. For example, here we can see that the leading edge of the ridge is actually composed of several smaller edges. The contact between the ridge and the surrounding smooth plains is softened toward the bottom right of the image, but near the top-left that contact is sharper. Continued high-resolution imaging of Mercury's wrinkle ridges will allow scientists to more thoroughly describe their various shapes, which in turn will help us understand why the ridges formed in the first place.
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: March 10, 2014
Image Mission Elapsed Time (MET): 36741405
Image ID: 5906004
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 69.7°
Center Longitude: 261.6° E
Resolution: 12 meters/pixel
Scale: The field of view in this image is about 6 km (4 mi.) across
Incidence Angle: 75.0°
Emission Angle: 6.9°
Phase Angle: 81.9°
North is to the right in this scene.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Wrinkle ridges are tectonic landforms observed across all of Mercury's smooth plains deposits, and are often superposed by impact craters. Craters themselves are frequently surrounded by lobate-like ejecta deposits, which at first glance might look like tectonic structures. In this image, a lobate-like feature runs parallel to the northern margin of an unnamed crater 20 km (12 miles) in diameter. Whether this landform is tectonic or impact-related is not yet clear, but with continued high-resolution imaging of other, similarly sized craters, we might be able to tell.
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: March 6, 2014
Image Mission Elapsed Time (MET): 36395675
Image ID: 5881419
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 66.3°
Center Longitude: 281.8° E
Resolution: 12 meters/pixel
Scale: The field of view in this image is 14 km (9 mi.) across
Incidence Angle: 70.5°
Emission Angle: 0.3°
Phase Angle: 70.2°
North is to the right in this scene.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This hill lies towards the edge of Mercury's expansive northern plains. The Sun was low in the sky (high incidence angle) when this image was acquired, resulting in a shadow approximately 3.3 km (2 miles) long. Using trigonometry and knowledge of the incidence angle, the height of the hill can be calculated: ~340 m (~0.2 mile). This hill might be the remnants of an old crater rim that was subsequently flooded. North is to the right of this image.
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: March 25, 2014
Image Mission Elapsed Time (MET): 38066727
Image ID: 6000245
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 83.92°
Center Longitude: 242.3° E
Resolution: 13 meters/pixel
Scale: This image is approximately 7 km (4.3 mi.) across.
Incidence Angle: 84.0°
Emission Angle: 1.9°
Phase Angle: 82.0°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
A large (180-km diameter) crater occupies the scene, but it has been almost completely buried by the volcanic plains that make up the northern smooth plains. The rim of the buried crater, especially in the southeast, has helped to localize compressional deformation, leading to a wrinkle-ridge ring. The center is criss-crossed by extensional graben.
These images were acquired as part of MDIS's high-incidence-angle base map. The high-incidence-angle base map complements the surface morphology base map of MESSENGER's primary mission that was acquired under generally more moderate incidence angles. High incidence angles, achieved when the Sun is near the horizon, result in long shadows that accentuate the small-scale topography of geologic features. The high-incidence-angle base map was acquired with an average resolution of 200 meters/pixel.
Date acquired: March 09, 2014
Image Mission Elapsed Time (MET): 36713179, 36713230
Image ID: 5903920, 5903921
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 64.4°
Center Longitude: 23.8° E
Resolution: 258 meters/pixel
Scale: The buried basin is approximately 180 km (112 miles) across
Incidence Angle: 86.2°
Emission Angle: 51.1°
Phase Angle: 137.3°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
The crater shown here, Boëthius, is 115 km (71 miles) in diameter. We have seen Boëthius before, when it was imaged by MESSENGER during its second flyby. Named for the early sixth-century Roman philosopher, Boethius has been filled with smooth plains that may be volcanic in origin. After that infilling, compressional stresses that are pervasive across the entire planet's surface resulted in the formation of the prominent lobate scarp that runs from top to bottom in the image. Boethius is yet another example of the Law of Superposition, which helps scientists to determine the sequence of events at any given location on Mercury.
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: February 1, 2014
Image Mission Elapsed Time (MET): 33546022
Image ID: 5678647
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 0.91° S
Center Longitude: 286.88° E
Resolution: 76 meters/pixel
Scale: The scene is 75 km (47 mi.) across
Incidence Angle: 72.8°
Emission Angle: 6.2°
Phase Angle: 66.6°
North is to the bottom in this image
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Today's image features the central peak complex of a large, unnamed crater on the plains surrounding the Caloris basin, roughly 400 km (250 mi) northwest of the crater Munch. The image has been stretched to highlight the details of the hollows that are forming on the crests of the peaks. The bright hollows on Mercury stand out in stark contrast to the low reflectance material with which they are frequently associated.
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: July 05, 2011
Image Mission Elapsed Time (MET): 218374017
Image ID: 466629
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 47.45°
Center Longitude: 145.6° E
Resolution: 30 meters/pixel
Scale: The image is about 31 km (19 mi.) wide
Incidence Angle: 48.0°
Emission Angle: 5.6°
Phase Angle: 53.7°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
The fiery yellow spots that stand out against the lower reflectance plains in this image are a series of pyroclastic vents stretching from roughly -60° latitude, within the crater Hesiod, to about -51° latitude. These vents are believed to have been the origins of explosive eruptions, driven by volcanic gases. Though they can be found across Mercury, this region contains one of the largest clusters of vents on the planet.
This image was acquired as a targeted color observation. Targeted color observations are images of a small area on Mercury's surface at resolutions higher than the 1-kilometer/pixel 8-color base map. During MESSENGER's one-year primary mission, hundreds of targeted color observations were obtained. During MESSENGER's extended mission, high-resolution targeted color observations are more rare, as the 3-color base map covered Mercury's northern hemisphere with the highest-resolution color images that are possible.
Date acquired: August 02, 2013
Image Mission Elapsed Time (MET): 17789351, 17789371, 17789355
Image ID: 4558440, 4558445, 4558441
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: -52.65°
Center Longitude: 329.5° E
Resolution: 777 meters/pixel
Scale: This image is about 725 km (450 mi.) wide at the top.
Center Incidence Angle: 58.9°
Center Emission Angle: 59.2°
Center Phase Angle: 28.0°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
The Tolstoj basin (355 km in diameter) can be seen at the bottom edge of the frame, its center filled with smooth plains and surrounded by a large region of low-reflectance ejecta. The fresh, bright-rayed crater Nureyev is visible near the limb.
This image was acquired as part of MDIS's limb imaging campaign. Once per week, MDIS captures images of Mercury's limb, with an emphasis on imaging the southern hemisphere limb. These limb images provide information about Mercury's shape and complement measurements of topography made by the Mercury Laser Altimeter (MLA) of Mercury's northern hemisphere.
Date acquired: November 21, 2013
Image Mission Elapsed Time (MET): 27346412
Image ID: 5238318
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: -4.37°
Center Longitude: 188.8° E
Resolution: 1015 meters/pixel
Incidence Angle: 14.6°
Emission Angle: 58.8°
Phase Angle: 63.2°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
The impact crater at the top center of this image is characterized by a sharp rim and high-reflectance ejecta. Lobes of slumped material are found where the wall meets the floor. The central peak is notable because it contains a pit. A recent survey1 found 27 central pit craters on Mercury. All of these central pit craters are located in plains units, but the mechanism by which the pits form is uncertain.
1 Z. Xiao and G. Komatsu (2013), Impact craters with ejecta flows and central pits on Mercury, Planetary and Space Science, vol. 82-83, pp. 62-78.
This image was acquired as part of MDIS's high-resolution surface morphology base map. The surface morphology base map covers more than 99% of Mercury's surface with an average resolution of 200 meters/pixel. Images acquired for the surface morphology base map typically are obtained at off-vertical Sun angles (i.e., high incidence angles) and have visible shadows so as to reveal clearly the topographic form of geologic features.
Date acquired: July 17, 2011
Image Mission Elapsed Time (MET): 219350124
Image ID: 513704
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 19.42°
Center Longitude: 63.27° E
Resolution: 143 meters/pixel
Scale: The impact crater of interest is about 17 km (11 mi.) in diameter
Incidence Angle: 59.8°
Emission Angle: 12.8°
Phase Angle: 47.0°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
The left side of today's image is dominated by an unnamed 75-km-diameter impact crater. The crater has several interesting features. Its western wall is quite broad, with extensive terracing and landslide scarps. The floor of the crater is flat, having been filled by volcanic plains or impact melt. The small central peaks, parts of the floor, and spots along the eastern rim are dotted with high-reflectance hollows. Finally, as outlined in the inset, the ejecta to the north and east of the rim appears to have flowed along the ground, and formed a terminal scarp. A recent paper by Beary Xiao and Goro Komatsu discusses this and other Mercurian craters that have flow-like ejecta, and makes comparisons with similar landforms on the Moon and Mars.
Z. Xiao and G. Komatsu (2013), Impact craters with ejecta flows and central pits on Mercury, Planetary and Space Science, vol. 82-83, pp. 62-78.
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: November 03, 2011
Image Mission Elapsed Time (MET): 228803487
Image ID: 966206
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 13.45°
Center Longitude: 298.0° E
Resolution: 182 meters/pixel
Scale: The scene is about 190 km (118 mi.) across
Incidence Angle: 68.6°
Emission Angle: 15.5°
Phase Angle: 55.3°
North is up in this image.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Mercury's surface has been extensively modified by tectonic activity. Giant thrust faults are thought to be the result of global cooling and contraction of the planet, and Mercury's smooth plains in particular are folded and wrinkled. With the Sun very low in the sky, the complexity of tectonic features in the northern volcanic plains is especially apparent. The wrinkle-ridge ring (also known as a "ghost crater") on the eastern edge of the scene was also captured here (see PIA15636) at more moderate illumination angles.
This image was acquired as part of MDIS's high-incidence-angle base map. The high-incidence-angle base map complements the surface morphology base map of MESSENGER's primary mission that was acquired under generally more moderate incidence angles. High incidence angles, achieved when the Sun is near the horizon, result in long shadows that accentuate the small-scale topography of geologic features. The high-incidence-angle base map was acquired with an average resolution of 200 meters/pixel.
Date acquired: November 12, 2013
Image Mission Elapsed Time (MET): 26543953
Image ID: 5181050
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 80.04°
Center Longitude: 86.24° E
Resolution: 230 meters/pixel
Scale: Scene is 125 km (78 miles) from top to bottom
Incidence Angle: 90.7°
Emission Angle: 49.8°
Phase Angle: 140.6°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
In contrast to a previous image, not all lobate scarps are large. The example pictured here is much smaller -- both in terms of length and relief -- than Discovery Rupes, but it too has contributed to the shortening of Mercury's crust. This scarp cross-cuts an unnamed, 65-km-diameter crater, which is filled with smooth plains, just north of Mussorgskij crater. Whether this scarp is younger than Discovery Rupes and so has not had as much time to accumulate tectonic deformation, or if instead it did not shorten the crust as much for other reasons, remains as yet unclear.
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: September 11, 2013
Image Mission Elapsed Time (MET): 21213842
Image ID: 4802121
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 35.4°
Center Longitude: 262.0° E
Resolution: 24.1 meters/pixel
Scale: The field of view in this image is about 29 km (18 mi.) from left to right
Incidence Angle: 60.59°
Emission Angle: 31.91°
Phase Angle: 28.68°
North is to the bottom of the image.
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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