Rays, Vents, and LRM near Picasso Crater

This color image emphasizes three major features of Mercury's surface: bright ejecta rays, explosive volcanic vents, and dark low reflectance material (LRM). The bright ray passing through the center of the image is part of Hokusai's immense system of rays. To the right, Picasso's arc-shaped pit is distinctive in color and contrasts with the patch of LRM to the crater's right.

Date acquired: September 17, 2011
Image Mission Elapsed Time (MET): 224718677, 224718685, 224718679
Image ID: 769641, 769646, 769642
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: 2.23°
Center Longitude: 46.34° E
Resolution: 1350 meters/pixel
Scale: Picasso crater is about 134 kilometers (83 miles) in diameter
Incidence Angle: 47.0°
Emission Angle: 0.2°
Phase Angle: 47.0°

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

Timgad Vallis

This image shows the fourth of five broad channels on Mercury for which names were recently approved (see Timgad Vallis). The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.

The vallis shown in this figure is named for Timgad, a Roman colonial town in the Algerian Aurès Mountains, founded around 100 CE. The city was abandoned after an Arab invasion in the 8th century CE, before being covered by the Sahara. The city ruins were excavated in 1881. The city’s population may have been as great as 15,000. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.

Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 59.6° N to 62.0° N
Feature Longitude Range: 114.3° E to 119.9° E
Feature Diameter: 116 km
Projection: Azimuthal equidistant

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

Paestum Vallis

This image shows the fourth of five broad channels on Mercury for which names were recently approved (see Paestum Vallis). The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.

The vallis shown in this figure is named for Paestum, a major Greco-Roman city in the Campania region of Italy. The city may have been founded in the 7th century BCE, but became a Roman city in 273 BCE. Paestum is renowned for its remaining Doric temples and a number of painted tombs, which date from the 5th century BCE. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.

Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 59.1° N to 61.0° N
Feature Longitude Range: 124.0° E to 128.5° E
Feature Diameter: 96 km
Projection: Azimuthal equidistant

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

Caral Vallis

This image shows the third of five broad channels on Mercury for which names were recently approved (see Caral Vallis). The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.

The vallis shown in this figure is named for Caral-Supe, a large settlement in the Barranca province of Peru that has been dated as one of the most ancient cities of the Americas, being inhabited from ca. 2627-1977 BCE. At its peak, Caral supported a population in excess of 3,000. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.

Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 61.8° N to 63.3° N
Feature Longitude Range: 128.3° E to 130.6° E
Feature Diameter: 64 km
Projection: Azimuthal equidistant

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

Cahokia Vallis

This image shows the second of five broad channels on Mercury for which names were recently approved (see Cahokia Vallis). The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.

The vallis shown in this figure is named for Cahokia Mounds, a Native American city that was the largest urban settlement in Mississippian culture (approx. 800-1500 CE). Cahokia contained hundreds of earthen mounds that supported the city's buildings. At its peak, the city may have been home to between 6,000 and 40,000 inhabitants. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.

Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 64.9° N to 66.7° N
Feature Longitude Range: 124.4° E to 128.5° E
Feature Diameter: 77 km
Projection: Azimuthal equidistant

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

Angkor Vallis

On April 30, 2013 the International Astronomical Union (IAU) Working Group for Planetary System Nomenclature approved new names for five broad valleys on Mercury (Angkor Vallis). These valleys have been interpreted by MESSENGER team scientists as having formed due to mechanical and thermal erosion of Mercury's surface by hot, low-viscosity, quickly-flowing lavas.

Each image this week will feature one of these five broad valleys, now termed "valles" (sing. "vallis") by the IAU. The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.

The vallis shown in this figure is named for Angkor city in Cambodia, the largest pre-industrial city in the world, and once the seat of the Khmer Empire. At its peak, Angkor hosted over 1,000 temples, including the world's largest religious monument. With a suburban footprint of ca. 1,000 km², Angkor at one time may have had a population of over 1 million people. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.

Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 56.2° N to 58.4° N
Feature Longitude Range: 112.7° E to 115.6° E
Feature Diameter: 95 km
Resolution: 250 meters/pixel
Projection: Azimuthal equidistant

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

Knobby Plains in Tir Planitia

The plains that surround the Caloris basin are geologically complex. Today's featured images highlights some of the kilometer-scale knobs that surround much of the basin, which are thought to be blocks of material ejected by the Caloris basin-forming event. This area, a region within Tir Planitia, has also been subjected to compressional stresses, which resulted in the formation of scarps that cut across the scene. Unraveling the complex sequence of events in this region, which includes deposition of ejecta, possible volcanic resurfacing, and tectonic deformation, will be aided by the high-resolution targeted images to be collected in MESSENGER's second extended mission.

Date acquired: April 05, 2013
Image Mission Elapsed Time (MET): 7472448
Image ID: 3825184
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 4.31°
Center Longitude: 185.6° E
Resolution: 61 meters/pixel
Scale: This scene is approximately 80 km (50 mi.) across
Incidence Angle: 73.6°
Emission Angle: 40.8°
Phase Angle: 114.1°

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

Degraded Impact Crater Rim

The rim of an unnamed peak-ring basin cuts across today's featured image. The basin is relatively degraded, but its rim still stands as a cliff over 1 km (0.6 miles) high. The face of this cliff, where downslope is toward the top of the image, is covered by a chain of secondary craters, whose formation on this steep slope led to somewhat asymmetrical crater shapes. It's hard to say which crater these secondaries originated from - the region is crossed by rays from Bronte, over 1700 km to the west, and Hokusai, over 2000 km to the east.

Date acquired: April 12, 2013
Image Mission Elapsed Time (MET): 8108630
Image ID: 3870271
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 41.15°
Center Longitude: 289.3° E
Resolution: 22 meters/pixel
Scale: This scene is approximately 25 km (16 miles) across
Incidence Angle: 64.0°
Emission Angle: 15.0°
Phase Angle: 79.0°

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

New Names for Five Mercurian Valles

From the USGS Astrogeology Science Center:

The Working Group for Planetary System Nomenclature has approved new names for five valles on Mercury: Angkor Vallis, Cahokia Vallis, Caral Vallis, Paestum Vallis, and Timgad Vallis. For more information, see the Gazetteer of Planetary Nomenclature.

High-Resolution Image of Area Southwest of Gauguin Crater

This is the highest resolution image taken to date of the planet Mercury! It shows an area just outside of a 33-km-diameter (21-mi.-diameter) crater to the southwest of Gauguin crater. The smooth areas here are likely filled with melt that was made and ejected as the crater formed. Only five images at resolutions better than 10 m/pixel have been taken in MESSENGER's first two years of orbital operations. If MESSENGER's second extended mission is approved, many more high-resolution images like this are planned.

Date acquired: April 30, 2012
Image Mission Elapsed Time (MET): 244286162
Image ID: 1738315
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 64.44°
Center Longitude: 257.5° E
Resolution: 7 meters/pixel
Scale: The diagonal of this image is approximately 11 km (7 mi.) across.
Incidence Angle: 70.0°
Emission Angle: 11.8°
Phase Angle: 81.8°

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

Degas Crater Rim

A portion of the rim of Degas crater is visible towards the top of this image. The hummocky texture of the interior crater wall is due to the slumping and downslope movement of material soon after the crater formed.

Date acquired: April 22, 2013
Image Mission Elapsed Time (MET): 8944037
Image ID: 3929664
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 36.35° N
Center Longitude: 232.6° E
Resolution: 24 meters/pixel
Scale: The diagonal of this image is approximately 36 km (22 mi.) across.
Incidence Angle: 43.6°
Emission Angle: 12.7°
Phase Angle: 56.3°

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

Red Spot Volcanic Crater

At the center of today's image is a "red spot," an informal designation used by the MESSENGER team to refer to an area with overall high reflectance and higher than average reflectance at the longer-wavelength (red) end of the spectrum. Red spots are thought to be sites of explosive (pyroclastic) volcanic eruptions. Such deposits were analyzed in a 2011 paper. A close-up of the crater at the center of the red spot was presented in a previous Gallery image. The crater neat the left edge of the image with bright floor deposits (hollows) is Theophanes.

Date acquired: December 14, 2011
Image Mission Elapsed Time (MET): 232328601, 232328621, 232328605
Image ID: 1134128, 1134133, 1134129
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: -3.73°
Center Longitude: 223.8° E
Resolution: 725 meters/pixel
Scale: The scene is about 750 km (465 mi.) wide.
Incidence Angle: 44.7°
Emission Angle: 0.3°
Phase Angle: 44.8°

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

Low Reflectance Impact Crater

Today's image is centered on a large unnamed crater to the northeast of Dali. The crater has been flooded with smooth plains that have a relatively high reflectance and reddish color compared to the average surface of Mercury. The surrounding area, by contrast, has low reflectance and blue color.

Date acquired: July 09, 2011
Image Mission Elapsed Time (MET): 218671363, 218671371, 218671365
Image ID: 480913, 480918, 480914
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: 47.75°
Center Longitude: 123.5° E
Resolution: 908 meters/pixel
Scale: The edges of the image are about 220 km (136 mi.) long.
Incidence Angle: 51.3°
Emission Angle: 0.4°
Phase Angle: 50.9°
The image was binned on the spacecraft from its original 1024 x 1024 pixel size to 256 square in order to reduce the volume of data that needed to be stored on the recorder and transmitted to Earth.

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

Peak of (Almost) Eternal Light

Studies of the illumination conditions near the north and south poles of Mercury are of interest because they can be used to determine locations of permanent shadow, extremely cold places where ice deposits lurk. However, the illumination maps also reveal the locations that receive the maximum duration of sunlight during a Mercury solar day. A "peak of eternal light" that is illuminated continuously for an entire solar day would be a favorable target for a lander, because solar power would be available all the time. So far, no such peak of eternal light has been identified at Mercury's south pole. The spot that get the most illumination (about 82%), is located at 89° S, 50.7° E. This place is indicated by the arrow in today's image.

This image was acquired as part of MDIS's campaign to monitor the south polar region of Mercury. By imaging the polar region approximately every four MESSENGER orbits as illumination conditions change, features that were in shadow on earlier orbits can be discerned and any permanently shadowed areas can be identified after repeated imaging over one solar day. During MESSENGER's one-year primary mission, MDIS's WAC was used to monitor the south polar region for the first Mercury solar day (176 Earth days), and MDIS's NAC made repeated images of the south polar region during the second Mercury solar day.

Date acquired: December 24, 2011
Image Mission Elapsed Time (MET): 233190744
Image ID: 1175166
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -88.17°
Center Longitude: 35.40° E
Resolution: 298 meters/pixel
Scale: The large crater is Chao Meng-Fu, about 129 km (80 mi.) in diameter.
Incidence Angle: 91.1°
Emission Angle: 7.1°
Phase Angle: 95.6°
Projection: Polar stereographic projection centered at 90° S, with
0° toward the top and 180° toward the bottom.

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

Snorri Crater

The bright, rayed crater in this image is one of the most prominent on Mercury. Named Snorri, after an Icelandic writer and poet, the crater was discovered in images returned by the Mariner 10 spacecraft. A color view of Snorri and surroundings was presented in a previous Gallery image (PIA14233).

Date acquired: October 14, 2011
Image Mission Elapsed Time (MET): 227045180
Image ID: 882221
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -9.42°
Center Longitude: 277.1° E
Resolution: 195 meters/pixel
Scale: Snorri is about 21 km (13 mi.) in diameter.
Incidence Angle: 22.4°
Emission Angle: 51.0°
Phase Angle: 73.4°

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

Alver Crater

Today's image features a perspective view of the Alver crater, recently named for Estonian poet Betti Alver (1906-1989). Alver's husband was imprisoned and died in Siberia after World War II, leading Alver to stop writing poetry for many years in protest of Soviet rule. She resumed writing poetry in the 1960s, composing the notable 1966 collection Tähetund or "Starry Hour."

To create this image, a portion of the MDIS monochrome basemap was draped over a digital elevation model. The topography has been exaggerated by 5 times to accentuate the crater rim and central peak ring. The view is looking towards the southeast. Alver is a complex crater in the southern hemisphere of Mercury. This perspective view highlights the smooth nature of the basin floor relative to the ejecta blanket and surrounding terrain.

Instrument: Mercury Dual Imaging System (MDIS)
Center Latitude: -67.0°
Center Longitude: 77.9° E
Basemap Resolution: approximately 250 meters/pixel
Digital Elevation Model: Produced by MESSENGER Participating Scientist Bob Gaskell based on MDIS images
Vertical Exaggeration: 5 times actual
Scale: Alver crater is 151.5 km (94.1 miles) across

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

Hurley and L'Engle Craters

Repeat imaging of Mercury's south pole has revealed that a number of craters in the south contain permanently shadowed regions. Because Mercury has only a very small axial tilt, the topography of crater rims, as accentuated in the inset image (shown with five times the vertical exaggeration of the actual topography), blocks sunlight from ever reaching portions of the floors of some polar craters.

This image features two such permanently shadowed craters which were recently named. Hurley crater, named for Australian James Francis Hurley (1885-1962), photographer of the famous Shackleton Expedition to Antarctica, is 67 km (42 mi.) wide and located within 3° of Mercury's south pole. The slightly smaller (62 km or 39 mi. wide) L'Engle crater is located to the east of Hurley. (Note that in the inset perspective image the view is towards the south). L'Engle crater is named for American author Madeleine L'Engle (1918-2007), best known for her young-adult novels including 'A Wrinkle in Time'. 'A Wrinkle in Time' blends adventure with quantum physics as it follows young heroine Meg on her journey through space to rescue her scientist father.

This primary image was acquired as part of MDIS's campaign to monitor the south polar region of Mercury. By imaging the polar region approximately every four MESSENGER orbits as illumination conditions change, features that were in shadow on earlier orbits can be discerned and any permanently shadowed areas can be identified after repeated imaging over one solar day. During MESSENGER's one-year primary mission, MDIS's WAC was used to monitor the south polar region for the first Mercury solar day (176 Earth days), and MDIS's NAC made repeated images of the south polar region during the second Mercury solar day. The inset image is a portion of the MDIS monochrome map draped over the Gaskell digital elevation model (with 5 times vertical exaggeration), as was also done for Monday's featured image.

Date acquired: August 03, 2011
Image Mission Elapsed Time (MET): 220899377
Image ID: 587366
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: -85.07°
Center Longitude: 67.57° E
Scale: The inset box is about 280 km (174 mi.) wide
Incidence Angle: 85.0°
Emission Angle: 23.4°
Phase Angle: 94.8°

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

Potential Volcanic Vent in Glinka Crater

The image above shows a potential volcanic vent within the crater Glinka. The resolution of this image is more than two times better than previous images of the same area. The crater Glinka was named for the Russian composer Mikhail Glinka (1804-1857). He is regarded as one of the fathers of Russian classical music. Glinka wrote several operas, piano pieces, orchestral works, and chamber music. His piece called "The Patriotic Song" was adopted as Russia's national anthem from 1990-2000.

Date acquired: November 26, 2012
Image Mission Elapsed Time (MET): 262402263
Image ID: 3026496
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 14.96°
Center Longitude: 247.4° E
Resolution: 44 meters/pixel
Scale: This image is 46 km (29 mi.) across.
Incidence Angle: 67.5°
Emission Angle: 3.1°
Phase Angle: 64.5°

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

Donalaitis Crater

The recently named Donalaitis crater near the center of this image exhibits bright reddish deposits on its floor, which contrast starkly with the more relatively blue hues of the surrounding terrain. Donelaitis crater was named for Kristijonas Donelaitis (1714-1780), a Lithuanian poet. His classic poem, 'The Seasons (Metai)', describes the lives of Lithuanian peasants, who at the time of its writing were being pushed into serfdom as most of their country was annexed by the Russian Empire.

Date acquired: August 21, 2011
Image Mission Elapsed Time (MET): 222408661, 222408681, 222408665
Image ID: 658976, 658981, 658977
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: -51.81°
Center Longitude: 39.11° E
Resolution: 874 meters/pixel
Scale: Donelaitis crater is 84.5 km (52.5 mi.) across.
Incidence Angle: 56.2°
Emission Angle: 0.5°
Phase Angle: 55.7°

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

Lovecraft and Roerich Craters

Today's image features a perspective view of two of the newly named craters near Mercury's south pole. To create this image, a portion of the MDIS monochrome basemap was draped over a digital elevation model. The topography has been exaggerated by 7 times to accentuate the rugged terrain formed by numerous overlapping craters.

In the foreground, sunlight highlights much of the rim of the dark Lovecraft crater, named for the American horror author Howard Phillips Lovecraft (1890-1937). The larger Roerich crater, named for the Russian painter Nicholas Roerich (1874-1947), lies slightly to the north of Lovecraft crater. One of Lovecraft's most famous works, 'At the Mountains of Madness' takes place on a scientific expedition to the south pole, and references Roerich's artwork--in particular, his paintings of the Tibetan plateau and the Himalayan Mountains. Portions of Lovecraft crater are shrouded in permanent darkness, and host radar-bright material. Similar deposits at the north pole have been associated with water ice and unusually dark material.

Instrument: Mercury Dual Imaging System (MDIS)
Center Latitude: -85.10°
Center Longitude: 284.8° E
Basemap Resolution: approximately 250 meters/pixel
Digital Elevation Model: Produced by MESSENGER Participating Scientist Bob Gaskell based on MDIS images
Vertical Exaggeration: 7 times actual
Scale: Roerich crater is 111.7 km (69.4 miles) across.

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