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