Creep in a Northern Mercurian Crater

This very high resolution image shows the interior of a crater in Mercury's northern hemisphere. Near the base of the crater's northern wall, we can see a subtle curving line, indicated by the arrows. The line represents the edge of a lobe of material that has likely formed by slow movement of loose regolith down the steeper parts of the crater wall under the action of gravity. Geologists refer to this type of movement as "creep."

Date acquired: February 26, 2012
Image Mission Elapsed Time (MET): 238781524
Image ID: 1445441
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 45.43°
Center Longitude: 298.8° E
Resolution: 13 meters/pixel
Scale: The edges of the image are about 14 km (8.7 mi.) long.
Incidence Angle: 69.9°
Emission Angle: 0.1°
Phase Angle: 70.0°

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

Blue Velvet

At the center of this scene is an area of dark, deep blue terrain. MESSENGER scientists refer to this as the "Low Reflectance Material (LRM)." Besides being dark across all wavelengths, the LRM reflects less light at longer wavelengths than does average Mercury material. Our eyes perceive light at the long wavelength end of the visible spectrum as red, and the short end as blue. Hence the LRM is said to have "blue" color relative to Mercury as a whole. Named craters in the scene include Kuiper, Yeats, Dominici, and Homer.

Date acquired: April 10, 2011
Image Mission Elapsed Time (MET): 210935602, 210935622, 210935606
Image ID: 114272, 114277, 114273
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: -2.50°
Center Longitude: 316.5° E
Resolution: 975 meters/pixel
Scale: The scene is about 1040 km (645 mi.) wide.
Incidence Angle: 13.3°
Emission Angle: 14.7°
Phase Angle: 28.0°

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

Munch Crater

This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. The scene shows a dramatic close-up of Munch crater, named for the Norwegian impressionist painter, printmaker, and draftsman Edvard Munch (1863-1944). On Wednesday, May 2nd 2012, one of four versions of Munch's famous 1895 pastel The Scream sold at auction for $119.9 million, becoming one of the most expensive pieces of artwork in the world.

Munch crater is situated within the Caloris basin, the youngest large impact basin on Mercury. The floor of Caloris has been flooded with volcanic flows. The ejecta blanket surrounding Munch contains dark material that originated at depth and was excavated by the Munch-forming impact. This dark material may correspond to rock types -- termed lithologies -- that are mineralogically distinct from those we see on the surface.

Date Created: February 10, 2012
Instrument: Mercury Dual Imaging System (MDIS)
Latitude Range: 39.2° N to 42.1° N
Longitude Range: 150.6° E to 155.3° E
Resolution: 140 meters/pixel
Scale: Munch crater is 58 km (36 mi.) in diameter
Projection: Azimuthal equidistant

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

Holst Crater

This image, taken with the Narrow Angle Camera (NAC), shows Holst crater. A peak-ring basin, Holst is one of 23 Mercury craters recently assigned names by the IAU. Holst was named for English composer Gustav Holst, who is best known for his orchestral suite The Planets -- the third movement of which is Mercury, the Winged Messenger.

Date acquired: January 12, 2012
Image Mission Elapsed Time (MET): 234830851
Image ID: 1254970
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -17.75°
Center Longitude: 44.65° E
Resolution: 147 meters/pixel
Scale: Holst crater is 170 km (106 mi.) in diameter
Incidence Angle: 67.0°
Emission Angle: 0.5°
Phase Angle: 67.2°

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

Ailey Crater

This image shows us a spectacular high-resolution view of newly named Ailey crater. Ailey is one of 23 Mercury craters recently assigned names by the IAU, and is named for the 20th century choreographer and activist Alvin Ailey. Ailey was best known for his role in revolutionizing African-American participation in 20th century concert dance and popularizing modern dance with pieces like his signature 1960 work, Revelations. Like its namesake, Ailey crater has revelations of its own, as landslides expose fresh material along the crater walls.

Date acquired: December 22, 2011
Image Mission Elapsed Time (MET): 233052079
Image ID: 1168964
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 45.51°
Center Longitude: 177.9° E
Resolution: 24 meters/pixel
Scale: Ailey crater is 21 km (13 mi.) in diameter
Incidence Angle: 46.2°
Emission Angle: 28.7°
Phase Angle: 74.9°

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

Wrinkle Ridges near Hokusai Crater

This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. The scene shows a region of smooth, volcanic plains that have been heavily modified by tectonic structures termed "wrinkle ridges." Occurring on the Moon and Mars as well as on Mercury, wrinkle ridges are low, sinuous features that form when lavas cool and subside, causing the crust to contract horizontally. These landforms are often concentrated around buried crater rims, forming circular wrinkle ridges like those in the center right of the image.

While the innermost planet hosts thousands of wrinkle ridges, they are largely confined to its smooth plains, and are morphologically different to the larger, longer faults that comprise Mercury's fold-and-thrust belts. By studying how the different types of tectonic features are distributed across Mercury, MESSENGER scientists can begin to document in detail how the planet has deformed through time.

Date Created: February 10, 2012
Instrument: Mercury Dual Imaging System (MDIS)
Latitude Range: 49.6° N to 60.9° N
Longitude Range: 16.5° E to 48.5° E
Resolution: 400 meters/pixel
Scale: Hokusai, the large, fresh impact crater at top left, is 90 km (56 mi.) in diameter.
Projection: Azimuthal equidistant

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

Balanchine Crater

The crater with bright material in the lower left corner of this image is the newly named Balanchine crater. Shown here in spectacular high resolution, Balanchine crater is one of 23 Mercury craters recently assigned names by the IAU. This crater was named for George Balanchine, one of the most famous choreographers of the 20th century and co-founder of the New York City Ballet.

Date acquired: December 22, 2011
Image Mission Elapsed Time (MET): 233051806
Image ID: 1168956
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 9 (996 nanometers)
Center Latitude: 40.36°
Center Longitude: 178.0° E
Resolution: 887 meters/pixel
Scale: Balanchine crater is 36 km (22 miles) in diameter
Incidence Angle: 41.3°
Emission Angle: 0.3°
Phase Angle: 41.0°

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

Spectral Web

The top image is a MASCS VIRS instrument color composite over a region of cratered plains on Mercury that includes craters Mena (upper left), Cezanne, Philoxenus, Chu Ta, and the unnamed "blue tongue" impact crater (lower right). Below is a contrast enhanced version of the MDIS mosaic without the VIRS overlay. In the VIRS color composite, the young rays of Mena and the blue tongue crater appear in yellows and oranges. Other colors in the VIRS composite are related to degree of space weathering and iron content of the surface materials.

Date Created: April 24, 2012
Instruments: Visible and Infrared Spectrograph (VIRS) of the Mercury Atmosphere and Surface Composition Spectrometer (MASCS), and Mercury Dual Imaging System (MDIS)
VIRS Color Composite Wavelengths: 575 nm as red, 415 nm/750 nm as green, 310 nm/390 nm as blue
Center Latitude: -4.5°
Center Longitude: 244.7° E
Resolution: 1 km/pixel
Scale: Crater Mena (upper left of mosaics) is 15 km (9 mi) across

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

Zeami Crater

This image, taken with the Narrow Angle Camera (NAC), gives us a good look at Zeami crater. Named for the 14th century Japanese actor and playwright Zeami Motokiyo, this crater displays a variety of features characteristic of complex craters on Mercury. We can see the remnants of an inner peak ring, terraced walls, and hollows scattered across the crater floor, especially near the top of the image.

Date acquired: April 08, 2012
Image Mission Elapsed Time (MET): 242378498
Image ID: 1621634
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -2.80°
Center Longitude: 212.7° E
Resolution: 186 meters/pixel
Scale: Zeami crater is 129 km (80 mi) in diameter.
Incidence Angle: 79.7°
Emission Angle: 26.7°
Phase Angle: 52.9°

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

Mercury Spectral Reflectance Map

This sinusoidal equal area projection map shows a color composite of Mercury spectral reflectance observed by the MASCS VIRS instrument over the MESSENGER primary mission. VIRS footprint tracks are RGB-colored where red is brightness at 575 nm; green is the visible to infrared brightness ratio (415 nm / 750 nm); and blue is the ultraviolet to visible ratio (310 nm / 390 nm).

Broad regional differences and local areas of interest stand out with combinations of ratio and brightness values that give clues to mineralogical composition. Younger surface materials that are brighter at visible wavelengths and less affected by the processes of space weathering show up in reds, yellows and greens. Materials that may have relatively higher iron contents (though still very low relative to most lunar or terrestrial crustal rocks) show up in blues.

In locations where multiple VIRS footprints cover the same area, the footprint with the best illumination for mineralogical interpretation (usually the lowest incidence angle where shadows are minimized) is used for making the map.

Date Created: April 10, 2012
Instrument: Visible and Infrared Spectrograph (VIRS) of the MESSENGER Atmosphere and Surface Composition Spectrometer (MASCS)
Center Latitude: 0°
Center Longitude: 0° E
Resolution: 16 km/pixel

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