Warhol Crater

Today's image is presented in the Pop Art style of American artist Andy Warhol. The upper left panel is the original MDIS three-color image. The other three panels are colorized to simulate Warhol's iconic silk-screened paintings. The name Warhol was recently approved by the International Astronomical Union for the large impact crater at the center of the scene. Warhol crater has an unusual elongated central peak, a smooth floor probably formed from impact melt, and abundant hollows.

Date acquired: October 21, 2011
Image Mission Elapsed Time (MET): 227644290
Image ID: 911008, 911007, 91106
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: -2.5°
Center Longitude: 354.0° E
Resolution: 359 meters/pixel
Scale: Warhol crater is about 95 km (59 mi.) in diameter.
Incidence Angle: 79.5°
Emission Angle: 56.3°
Phase Angle: 135.9°

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

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

Impact Craters in Goethe Basin

The two large craters in this scene are located in Goethe basin, a 383-km-diameter basin in the northern plains of Mercury. Portions of these craters are in areas of permanent shadow and host radar-bright materials.

Date acquired: March 29, 2012
Image Mission Elapsed Time (MET): 241545232
Image ID: 1580685
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 82.99°
Center Longitude: 314.2° E
Resolution: 67 meters/pixel
Scale: The upper crater is approximately 25 km (15.5 mi.) in diameter.
Incidence Angle: 83.0°
Emission Angle: 28.3°
Phase Angle: 83.7°

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

Debussy Crater

This color image of Mercury's limb captures Debussy, a crater 80 km (50 mi.) in diameter, as well as some if its extensive rays. The crater and its rays appear brighter than the surrounding material because the crater is relatively young and the excavated materials have not been substantially darkened by space weathering.

Date acquired: March 21, 2012
Image Mission Elapsed Time (MET): 240854845, 240854865, 240854849
Image ID: 1545794, 1545799, 1545795
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: -36.20°
Center Longitude: 60.40° E
Resolution: 2858 meters/pixel
Scale: Mercury's diameter is 4880 kilometers (3030 miles)
Incidence Angle: 79.5°
Emission Angle: 66.7°
Phase Angle: 78.7

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

Victoria Rupes

This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. The scene, with north to the right, shows a geological feature termed Victoria Rupes -- a long cliff or scarp that formed when Mercury shrank slightly as its core cooled. Rupes on Mercury are named for ships of discovery, and Victoria Rupes is named for the Victoria that formed part of Ferdinand Magellan's fleet in his 1519-1522 effort to circumnavigate Earth.

This geologic feature is of particular interest to MESSENGER scientists because it is part of a larger, linear set of contractional structures that may correspond to what is termed a fold-and-thrust (FAT) belt on Earth. FAT belts are common terrestrial surface features, and form when the crust is shortened due to compressional tectonism. Identifying FAT belts on Mercury will help scientists understand in more detail how that planet's crust has deformed through time.

Date Created: February 10, 2012
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Latitude Range: 47° N to 59° N
Longitude Range: 321° E to 331° E
Resolution: 250 meters/pixel
Scale: The crater just left of center is approximately 42 km (26 mi.) in diameter
Projection: Azimuthal equidistant

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

Lava Channels Near Kofi Crater

This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. Of particular note is the flat-floored, southeast-trending valley in the center of the image, which starts near several depressions to the top left of the image, and connects with the Kofi crater (center right).

This valley is interpreted by MESSENGER team scientists as a broad lava channel, formed by the mechanical and thermal erosion of Mercury's surface by hot, low-viscosity, quickly-flowing lavas. The pits to the top left may be source vents for the lava flows that formed the channel; these flows then filled the Kofi crater at the channel's other end. Another lava channel, with a similar southeast trend, lies at the top right of the image, and there is a total of five broad channels in this region.

Determining how these channels formed, how rapidly they shaped the landscape, and how they relate to other volcanic features on Mercury -- such as expansive smooth plains nearby -- is important in understanding the role of volcanism on Mercury. Moreover, similar broad channels do not appear to exist elsewhere on Mercury, making this region a particularly interesting locale.

Date Created: February 10, 2012
Instrument: Mercury Dual Imaging System (MDIS)
Latitude Range: 54.3° N to 61.3° N
Longitude Range: 109.4° E to 121.6° E
Resolution: 146 meters/pixel
Scale: Kofi, the large impact crater at center right, is approximately 135 km (84 mi.) in diameter
Projection: Azimuthal equidistant

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

Caloris Basin

This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. Caloris Basin, the largest young impact crater on Mercury, dominates the scene. With an east-west diameter of 1,640 km, Caloris hosts a wide variety of tectonic features, including graben, ridges, and Pantheon Fossae. MESSENGER team members are in the process of mapping the tectonic features within the Caloris basin and deciphering their complicated relationships.

MESSENGER scientists are interested in the tectonic features of Caloris as the basin shows widespread evidence of both extension and compression, an uncommon tectonic combination on Mercury. Since different processes produce extensional and contractional landforms, the Caloris basin has clearly had a complex and detailed geological history. Understanding how these structures developed will yield an insight into tectonism in Mercury's largest basin, and large impact craters in general.

Date Created: February 10, 2012
Instrument: Mercury Dual Imaging System (MDIS)
Latitude Range: 12° N to 52° N
Longitude Range: 139° E to 187° E
Resolution: 1720 meters/pixel
Scale: The large crater at center right (Atget crater) is 100 km (63 mi.) in diameter
Projection: Azimuthal equidistant

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

Degas Crater

Degas crater is shown here in spectacular detail. This high-resolution mosaic is made up of five separate images. The floor of the crater contains cracks that formed as the melt sheet cooled and contracted. Downslope movement of material on the central peaks and walls has exposed fresh, bright material.

Date acquired: April 07, 2012
Image Mission Elapsed Time (MET): 242296379, 242338160, 242338176, 242338192, 242379971
Image ID: 1617565, 1619567, 1619568, 1619569, 1621694
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 37.1°
Center Longitude: 232.7° E
Resolution: 32.5 meters/pixel
Scale: Degas is approximately 53 km (33 mi.) in diameter.
Incidence Angle: 68.5°
Emission Angle: 15.6°
Phase Angle: 52.8°

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

Note: This image looks very similar to a photo of De Graft Crater, taken earlier this year.

The Southern Wall of Stravinsky Crater

The structure running across the center of this image is the southern wall of the 190-kilometer diameter crater Stravinsky. Numerous small craters pepper the scene. One small crater in particular, near the westernmost extent of the image, appears to have some darker material streaming down the wall. That small crater is approximately 170 meters in diameter, which is slightly less than the length of two football fields.

Date acquired: April 02, 2012
Image Mission Elapsed Time (MET): 241837210
Image ID: 1594982
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 50.29°
Center Longitude: 281.2° E
Resolution: 20 meters/pixel
Scale: An edge of this image is approximately 22 kilometers (14 miles) long.
Incidence Angle: 56.9°
Emission Angle: 19.6°
Phase Angle: 76.6°

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

Carducci Crater

This image shows two craters that formed from impacts on Mercury's surface at a very similar location. The largest crater in this image is named Carducci, in honor of the Italian poet Giosue Carducci (1835-1907). The smaller crater that is located near the center of Carducci has a diameter of approximately 20 kilometers. We can deduce that the smaller crater is younger than Carducci because the impact that formed the smaller crater destroyed a portion of Carducci's central peaks and a large impact crater like Carducci would have obliterated any evidence of the smaller crater if the smaller crater had existed previously. Simple superposition relationships like this are being applied all over Mercury's surface, to determine the relative age and timing of events in Mercury's past.

Date acquired: April 01, 2012
Image Mission Elapsed Time (MET): 241789276
Image ID: 1592870
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -36.80°
Center Longitude: 270.2° E
Resolution: 222 meters/pixel
Scale: The diameter of Carducci is 108 kilometers (67 miles)
Incidence Angle: 54.8°
Emission Angle: 4.4°
Phase Angle: 59.3°

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

Spectral Map of Mercury

This sinusoidal equal area projection map shows the ground coverage on Mercury by the MASCS VIRS instrument. The coverage tracks are shaded by brightness measured by VIRS at 750 nm. A pixel is counted as 'observed' if any portion of it is covered by a VIRS footprint. By this method, over 81% of the surface has been observed in the primary mission of MESSENGER, with more to come in the extended mission. In locations where multiple VIRS footprints cover the same area, the footprint with the best viewing geometry (usually the lowest incidence angle) is counted for coverage, and for making spectral maps of the surface. These spectral maps are helping the MESSENGER team understand the composition and mineralogy of Mercury's surface.

Date Created: April 2, 2012
Instrument: Visible and Infrared Spectrograph (VIRS) of the MESSENGER Atmosphere and Surface Composition Spectrometer (MASCS)
Center Latitude: 0°
Center Longitude: 0° E
Resolution: 20 km/pixel

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

Jokai Crater

Acquiring high-incidence-angle images of Mercury's surface is a major mapping activity in MESSENGER's extended mission. The high-incidence campaign compliments the surface morphology base map of MESSENGER's primary mission, which 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 is being acquired with an average resolution of 200 meters/pixel.

This image is part of the high-incidence campaign and shows part of Jokai crater, a 93 km (58 mi.) diameter complex crater named for the 19th century Hungarian novelist Mor Jokai. Two smaller craters overprint the rim of Jokai. Jokai itself overprinted a similarly-sized crater, and part of the remaining older crater's wall can be seen towards the left side of this image.

Date acquired: April 11, 2012
Image Mission Elapsed Time (MET): 242631251
Image ID: 1633957
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 71.3°
Center Longitude: 224.0° E
Resolution: 173 meters/pixel
Scale: The small, shadowed crater at the center of the image is approximately 14 km (8.7 mi.) in diameter.
Incidence Angle: 80.4°
Emission Angle: 11.2°
Phase Angle: 69.1°

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

Sholem Aleichem Crater

Acquiring high-resolution 3-color images of Mercury's surface is a major mapping activity in MESSENGER's extended mission. The 3-color campaign complements the 8-color base map (at an average resolution of 1 km/pixel) acquired during MESSENGER's primary mission by imaging Mercury's surface in a subset of the color filters at the highest resolution possible. The three narrow-band color filters are centered at wavelengths of 430 nm, 750 nm, and 1000 nm, and image resolutions generally range from 100 to 400 meters/pixel in the northern hemisphere.

This image was acquired as part of MDIS's high-resolution 3-color imaging campaign, and shows a portion of the 196-kilometer diameter crater Sholem Aleichem. In this view, bright hollows appear to be associated with dark material, while a deposit on the crater's floor has a brighter orange hue, similar to that in areas associated with explosive volcanism.

Date acquired: April 03, 2012
Image Mission Elapsed Time (MET): 241962499, 241962491, 241962495
Image ID: 1601144, 1601142, 1601143
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (1000, 750, 430 nanometers) in red, green, and blue
Center Latitude: 51.01°
Center Longitude: 266.4° E
Resolution: 148 meters/pixel
Scale: An edge of this image is approximately 135 kilometers (84 miles)
Incidence Angle: 62.0°
Emission Angle: 0.2°
Phase Angle: 62.0°

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

Red Mercury

Today's image shows a color view of the southern rim of the Caloris impact basin. The prominent reddish spots are associated with irregular depressions that are thought to be volcanic vents. The reddish deposits are probably formed of pyroclastic material ejected from the vents during explosive eruptions. The images were binned on the spacecraft from their original size of 1024 by 1024 to 256 by 256 pixels in order to manage space on the solid-state data recorder.

Date acquired: July 03, 2011
Image Mission Elapsed Time (MET): 218203157
Image ID: 458358
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 996-nm, 559-nm, 433-nm as red-green-blue.
Center Latitude: 13.61°
Center Longitude: 154.4° E
Resolution: 1896 meters/pixel
Scale: The edges of the image are about 490 km (300 mi.) long
Incidence Angle: 14.4°
Emission Angle: 13.5°
Phase Angle: 28.0°

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

Note: The title for this post is a play on another recent post, Blue Mercury.

Crater Chain

This view shows a remarkable line of secondary craters, formed by a set of similar-sized blocks thrown out by the impact that formed an unnamed 150-km diameter crater, whose rim is just to the southeast of the lower right end of the crater chain. The individual secondary craters in the chain are each about 4 to 6 km wide. The uniformity of the size of these secondaries and their arrangement in a line nearly radial to the center of the primary crater hint at the complex physics involved in the impact process.

Date acquired: January 20, 2012
Image Mission Elapsed Time (MET): 235551551
Image ID: 1289763
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -35.87°
Center Longitude: 19.45° E
Resolution: 175 meters/pixel
Scale: The scene is about 211 km (130 mi.) wide.
Incidence Angle: 68.3°
Emission Angle: 36.1°
Phase Angle: 97.3°

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

Ride Along with the NAC

This high-resolution image of Mercury's limb is part of a new type of observation that MESSENGER will use throughout the extended mission: the NAC ride-along imaging campaign. When data volume is available and MDIS is not acquiring images for its other campaigns, high-resolution NAC images are obtained of the surface. These images are designed not to interfere with other instrument observations but take full advantage of periods during the mission when extra data volume is available. If you look closely, you may also notice some bright speckles on Mercury and in space. These are due to the recent solar storm.

Date acquired: March 08, 2012
Image Mission Elapsed Time (MET): 239703718
Image ID: 1490467
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 1.60°
Center Longitude: 356.5° E
Resolution: 165 meters/pixel
Scale: Scene is approximately 160 km (100 miles) from top to bottom
Incidence Angle: 4.2°
Emission Angle: 82.3°
Phase Angle: 78.0°

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

Blue Mercury

The upper part of this view of Mercury's surface includes a swath of material that has reflectance that does not strongly increase toward longer wavelengths, a property described as relatively "blue" in color. The bluish material also has lower overall reflectance than Mercury's average surface. The terrain to the south and west has a more reddish color. A major puzzle of Mercury's geology is the identity of the particular rock types that correspond to these colors. Visible in the scene are the craters Amaral, Neruda and Sher-Gil.

Date acquired: July 05, 2011
Image Mission Elapsed Time (MET): 218360003
Image ID: 466480, 466483, 466481
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 996-nm, 558-nm, 433-nm as red-green-blue.
Center Latitude: -51.62°
Center Longitude: 131.1° E
Resolution: 2471 meters/pixel
Scale: The edges of the image are about 2750 km (1700 mi.) long.
Incidence Angle: 55.3°
Emission Angle: 0.9°
Phase Angle: 55.5°

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

Radar-Bright Deposits in Mercury's North Polar Region

MESSENGER's highly eccentric orbit, which passes low over Mercury's north polar region, enables higher-resolution views of Mercury's surface in the north than in the south. Shown here is a subset of this image; the large 100-km diameter crater in the center is located at 72.5° N, 67.4° E and was recently named Stieglitz, for the American photographer Alfred Stieglitz. Of particular note are the craters hosting radar-bright features at low latitudes, extending southward to 67° N, and the many small craters that host radar-bright deposits. Low-latitude and small craters provide thermally challenging environments for water ice to persist. A thin (few tens of centimeters thick) layer of insulation is likely required to cover and to lower the temperature of these deposits if they are water ice. However, the smallest craters and the lowest-latitude locations may prove a challenge for water ice stability over extended periods of geologic time even with such cover.

Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)

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

Note: For a similar image showing a wide-area map of the north polar region, see PIA15530: Radar-bright Deposits near Mercury's North Pole.

Shadowed Terraces

This image provides a look at the curvy walls and terraces of an unnamed crater located in the vast expanse of volcanic plains in Mercury's northern region. North is toward the top right corner.

Date acquired: March 15, 2012
Image Mission Elapsed Time (MET): 240291628
Image ID: 1519191
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 68.98°
Center Longitude: 31.48° E
Resolution: 23 meters/pixel
Scale: Scene is approximately 12 km (7 miles) across
Incidence Angle: 73.1°
Emission Angle: 11.3°
Phase Angle: 84.5°

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

Mercury South Polar Illumination Map

Shown here is an illumination map of Mercury's south polar region. The map is colored on the basis of the percentage of time that a given area is sunlit; areas appearing black in the map are regions of permanent shadow. This map was created by using 89 wide-angle camera (WAC) images of Mercury's south polar region acquired by the Mercury Dual Imaging System (MDIS) over one complete Mercury solar day (176 Earth days) which can be viewed in this movie. Radar-bright deposits, which may be water ice, collocate with regions of permanent shadow.

Scale: The large crater near Mercury's south pole, Chao Meng-Fu, has a diameter of 180 km
Map Information: This illumination map is shown in polar stereographic projection, extending northward to 73° S, and 0° longitude is at the top

Map credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/Byrne et al.

Map of Northern Shadows

MESSENGER's highly eccentric orbit passes high above Mercury's south pole and low over Mercury's north polar region. Consequently, unlike for the south, a single WAC image cannot view the entire north polar region. However, more than 6,000 WAC images have been acquired of Mercury's north polar region, providing views under different illumination conditions over two Mercury solar days. These images allow areas to be mapped that are in shadow in all MDIS images to date. This mosaic shows a view of Mercury's north polar region assembled from those images, with areas in shadow shown in red. A small fraction of Mercury's surface near the north pole has yet to be imaged and is the focus of a new imaging campaign in MESSENGER's newly inaugurated extended mission. Radar-bright features near Mercury's north pole, that may be water ice, collocate with shadowed areas.

Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Scale: On Mercury, 5° of latitude is approximately 213 km
Map Information: Polar stereographic projection with every 5° of latitude and 30° of longitude indicated and with 0° longitude at the bottom

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

Mercury's Topographic Map of the Northern Hemisphere

The Mercury Laser Altimeter (MLA) ranges at a wavelength of 1064 nm at an 8 Hz rate and illuminates Mercury's surface in spots between 15 and 100 m across, depending on the MESSENGER spacecraft's range. The MLA has so far returned 10.7 million precise measurements of the elevation of Mercury's northern hemisphere. Shown here is a polar stereographic projection of the topography of Mercury from the north pole to 5° S. The outlines of selected major impact structures are shown as black circles.

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

New Moon Discovered Orbiting Mercury

This discovery image provides the first evidence that Mercury has a small natural satellite or moon. Visible as a small bright spot in an image taken yesterday by the Mercury Dual Imaging System (MDIS) Wide Angle Camera (WAC), the moon is approximately 70 meters (230 feet) in diameter and orbits Mercury at a mean distance of 14,300 km (8,890 miles). A proposal to name the moon "Caduceus," after the staff carried by the Roman god Mercury, has been submitted by the MESSENGER team to the International Astronomical Union, the body responsible for assigning names to celestial objects.

This discovery presents an unprecedented opportunity for a return of samples from the Mercury system, as Project Scientist Nat MacRulf explains. "We have yet to identify a sample from Mercury in any of the meteorite collections we have here on Earth. Such a sample would give us critical insight into the chemical composition of Mercury and the timing of crustal formation on that body, leading to a better understanding of how the planet formed and evolved. If we could obtain a sample of Caduceus, it would enhance the scientific return of the MESSENGER mission beyond our wildest dreams!"

Work on designing a scenario for sample return is already underway. MESSENGER Project Manager Burt Panini held an emergency meeting with the MESSENGER mission operations and navigation teams yesterday evening to determine if the spacecraft could be targeted toward the diminutive moon. After an intensive discussion, a unanimous decision was taken to abandon the orbit-correction maneuvers that had been planned for later this month to place the spacecraft in an eight-hour orbit. Instead, the new plan is to use the remaining propellant to crash MESSENGER into Caduceus. "Our detailed analysis tells us that if we act now, and with the right trajectory, MESSENGER will impart just enough momentum to the moon to break it free of Mercury's gravity well and set it on an Earth-crossing trajectory suitable for recovery as a Mercury meteorite," said Panini.

This action will form the basis of a new request to NASA by the MESSENGER team for an extended extended mission, tentatively called "MESSENGER Infinitesimally Nudging Caduceus," or MIN-C for short. Once MIN-C is approved by NASA, the spacecraft will be targeted for a collision trajectory. If Caduceus is successfully released from the pull of Mercury and placed on a course to reach Earth, we can expect the moon to arrive at Earth by 2014. "The risk to the public is reassuringly small", offers MESSENGER mission design lead Adam McJames. "We have designed a trajectory that will bring the moon to Earth at a remote location on the Wilkes Land ice sheet in Antarctica. This trajectory will avoid all population centers and will put the moon's impact site within reach for retrieval by the scientific staff at the U.S.-operated McMurdo Station."

If successful, MESSENGER's extended extended MIN-C mission will mark the first instance of the documented arrival to Earth of material from the Mercury system. Moreover, it will serve as the basis for a new Discovery-class mission proposal currently in development by the Applied Psychics Laboratory for a Mercury lander mission for in situ X-ray analysis of surface composition. That mission is to be named the Hermean On-surface Analysis with X-rays.

Date acquired: March 31, 2012
Image Mission Elapsed Time (MET): 131766564
Image ID: 6418
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 38.15°
Center Longitude: 66.18°
Resolution: 410 meters/pixel (0.25 miles/pixel) in the lower left corner of the image
Scale: The large crater in the center of the image (Copland) is about 210 kilometers (130 miles) in diameter.
Spacecraft Altitude: 16,200 kilometers (10,070 miles)
Incidence Angle: 69.1°
Emission Angle: 80.8°
Phase Angle: 138.2°

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

Hodgkins Crater in Color

We recently got a high-resolution look at Hodgkins crater. Today's featured image is a great example of how MDIS's two cameras complement each other: the NAC (narrow-angle camera) provides the high resolution and the WAC provides a lower resolution view in color. Usually the ejecta of fresh craters is relatively blue, but like Kuiper crater, Hodgkins continuous ejecta blanket is redder. In this case, it appears that Hodgkins has exposed a compositionally distinct material.

Date acquired: March 15, 2012
Image Mission Elapsed Time (MET): 240290904, 240290900, 240290896
Image ID: 1519152, 1519151, 1519150
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: 28.60°
Center Longitude: 17.71° E
Resolution: 251 meters/pixel
Scale: Hodgkins crater (center) is approximately 18 km (11 miles) in diameter
Incidence Angle: 35.8°
Emission Angle: 12.6°
Phase Angle: 48.4°

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

Topographic Map of Mercury's Northern Plains

Shown here is a perspective view of the immense volcanic plains that span Mercury's northern latitudes, colorized by the topographic height of the surface. The purple colors are the lowest and white is the highest. The total dynamical range of the height variation measured on Mercury is roughly 10 km, which is a smaller range than is found on either the Moon (20 km) or Mars (30 km).

Map Details: Every 5 degrees in latitude and longitude is marked
Scale: On Mercury, 5 degrees of latitude is approximately 213 kilometers (132 miles)

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