Saturday, March 29, 2014

Impact Crater Intersection


This high-resolution image shows the intersection of two crater rims. The full craters can be seen in this context image -- the high-resolution image covers the rim intersection very close to the context image center. Downslope movement of material in the crater wall has exposed fresh, brighter soil.

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): 36770148
Image ID: 5908044
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 65.02°
Center Longitude: 255.4° E
Resolution: 12 meters/pixel
Scale: This image is approximately 8.8 km (5.5 mi.) across.
Incidence Angle: 73.1°
Emission Angle: 5.8°
Phase Angle: 78.9°

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

Thursday, March 27, 2014

Double Impact Craters


These two relatively fresh craters, ~34 km (21 miles) and ~20 km (12 miles) across, share a rim and both contain slumped material. Did they form during the same event, by two impactors? Did the rim of the large, highly degraded crater on the right side of the image influence the structure of the shared rim? Higher-resolution images taken during MESSENGER's final year of operations may help to elucidate their origin.

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: October 12, 2011
Image Mission Elapsed Time (MET): 226922649
Image ID: 876240
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 64.76°
Center Longitude: 255.5° E
Resolution: 269 meters/pixel
Scale: The large crater at the image center is approximately 34 km (21 mi.) across.
Incidence Angle: 72.9°
Emission Angle: 14.3°
Phase Angle: 60.6°

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

Wednesday, March 26, 2014

Rim of an Unnamed Crater


This stunning image shows a portion of the sharp rim of an unnamed, ~28 km (17 mile) diameter complex crater. The upper right portion of the image lies outside of the crater, and the lower left portion of the image lies on the crater floor. The crater at the center of the image lies on the crater wall. North is to the right.

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 14, 2014
Image Mission Elapsed Time (MET): 37087259
Image ID: 5930668
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 78.14°
Center Longitude: 278.3° E
Resolution: 16 meters/pixel
Scale: This image is approximately 10.5 km (6.5 mi.) across.
Incidence Angle: 78.4°
Emission Angle: 39.7°
Phase Angle: 118.1°

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

Saturday, March 22, 2014

Mercury by Messenger's MASCS and VIRS Instruments


The Sun's light provides a powerful tool for understanding the composition of materials in the Solar System. Today's image features two views of Mercury provided by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) instrument. As the Sun's light hits the surface of Mercury, the Visible and Infrared Spectrograph (VIRS) portion of MASCS measures many wavelengths of the reflected light from a single spot on the surface at a time. These observations create a spectral profile of the surface as MESSENGER orbits Mercury. In each panel, the top left corner of the image is 70°N,180°E and the bottom right corner is 70°S,180°E. Most of Caloris basin can be seen along the right edge of each panel. The top panel is a monochromatic image of the interpolated 750 nm reflectance, and the bottom panel shows the same data but in a false color composite selected to highlight compositional variations on the surface.

The monochromatic map is part of a data set that was released to the public earlier this month through the Planetary Data System (PDS). In conjunction with the release, the team hosted a Data User's Workshop at the 45th Lunar and Planetary Science Conference, which is being held this week in The Woodlands, Texas.

Instruments: Visible and Infrared Spectrograph (VIRS) of the Mercury Atmosphere and Surface Composition Spectrometer (MASCS)
Center Latitude:
Center Longitude: 0° E
Map Projection: Simple Cylindrical
VIRS Monochromatic Wavelength: 750 nm
VIRS Color Composite Wavelengths: 575 nm as red, 415 nm/750 nm as green, 310 nm/390 nm as blue
Scale: Caloris Basin is 1,550 km (963 mi) across.

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

Thursday, March 20, 2014

Geological Structure Map of Mercury


Scientists have known since Mariner 10 that Mercury has contracted. This contraction is a result of the cooling of Mercury's interior, and is the process responsible for the formation of the planet's wrinkle ridges and lobate scarps. For almost four decades, however, the amount of global contraction measured from spacecraft data has been substantially less than that predicted by models of the thermal evolution of Mercury.

Now, using global photogeological and topographic MESSENGER data of Mercury, members of the MESSENGER team have mapped almost 6,000 ridges and scarps across the planet. Today's image shows the result of this mapping work, with structures color-coded according to one of four classes. (The global photogeological and topographic data used in this study are shown in the bottom left and right, respectively, of the image.) With these results, the MESSENGER team has calculated that Mercury contracted to a much greater extent than had been determined previously from mapping -- by up to seven times more, in fact.

This study was published online in the journal Nature Geoscience on Sunday, March 16, 2014, and is being presented today in the "Mercury" session at the 45th Lunar and Planetary Science Conference, which is being held this week in The Woodlands, Texas. In total, MESSENGER team members are presenting 25 papers at this conference.

Date published online: March 16, 2014
Center Latitude:
Center Longitude: 0°E
Projection: Molleweide
Reference: Byrne et al. (2014) Mercury's global contraction much greater than earlier estimates, Nature Geoscience, doi:10.1038/NGEO2097

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

Tuesday, March 18, 2014

Fault Scarp


New images obtained during low-altitude opportunities when the MESSENGER spacecraft is closest to the surface have revealed a small lobate scarp, identified here with white arrows. Cooling of Mercury's interior over billions of years has caused the planet to contract, forming a network of large landforms called lobate scarps, many over a kilometer high and hundreds of kilometers long. One of the goals for MESSENGER's current extended mission is to determine if there is evidence of young fault scarps that indicate recent contraction of Mercury due to interior cooling and continued solidification of the core. This scarp is only 2 km long, the shortest fault scarp yet found on Mercury. Landforms of this scale must be young, because small features will not survive for billions of years under constant meteoroid bombardment. Lobate scarps of the same scale found on the Moon are thought to be no more than 800 million years old and could be less than 50 million years old. Thus, this small scarp and others likely to be discovered in low-altitude images could provide evidence of very recent contraction of 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 better than that of 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 09, 2014
Image Mission Elapsed Time (MET): 34263837, 34263839
Image ID: 5729947, 5729948
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 65.8°
Center Longitude: 64.8° E
Resolution: 17 meters/pixel
Scale: 2-kilometer (1.2-mile) scale bar shown on the image
Incidence Angle: 79.7°
Emission Angle: 33.5°
Phase Angle: 113.3°

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

Saturday, March 15, 2014

Berkel Crater


MESSENGER's first orbital image, the first ever obtained from a spacecraft in orbit about Mercury, showed a large region of the planet, including the crater Berkel. Monday will mark three years since the MESSENGER spacecraft entered into orbit about Mercury. Over 200,000 images have been captured since that first orbital view, including the striking image of Berkel shown here, which shows new details of Berkel's dark, low-reflectance material, excavated during the impact that formed the crater.

This image was acquired as part of 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.

Date acquired: February 16, 2014
Image Mission Elapsed Time (MET): 34838972
Image ID: 5770878
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -14.11°
Center Longitude: 26.85° E
Resolution: 41 meters/pixel
Scale: Berkel crater is 22 kilometers (14 miles) in diameter
Incidence Angle: 33.2°
Emission Angle: 48.4°
Phase Angle: 30.1°
Orientation: North is toward the bottom of this image.

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

Friday, March 14, 2014

Hollows in Sholem Aleichem Crater


This image, just captured last week, shows Mercury's hollows in the highest resolution yet achieved! These hollows are located on the wall of Sholem Aleichem, within a region of low-reflectance material.

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: March 07, 2014
Image Mission Elapsed Time (MET): 36539529
Image ID: 5891638
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 51.90°
Center Longitude: 267.53° E
Resolution: 7.9 meters/pixel
Scale: This image is about 8 kilometers (5 miles) across
Incidence Angle: 63.2°
Emission Angle: 14.9°
Phase Angle: 78.0°

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

Tuesday, March 11, 2014

Detail From The New Three-Color Mosaic


A new color mosaic created from MESSENGER images is now available! This mosaic was part of a release on March 7, 2014 by NASA's Planetary Data System (PDS). A portion of the new color mosaic is shown here; can you find the craters Debussy, Derain, Berkel, and Warhol in this view? Explore the full 3-color mosaic (and confirm the locations of these craters) in QuickMap.

The images for MDIS's high-resolution 3-color mosaic were acquired during MESSENGER's second year in orbit about Mercury. The 3-color mosaic was designed to complement the 8-color base map acquired during MESSENGER's primary mission. By imaging Mercury's surface in a subset of the color filters at the highest resolution possible, the 3-color mosaic is available at 332 meters/pixel,as compared to 665 meters/pixel for the 8-color mosaic.

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: -14.9°
Center Longitude: 10.3° E
Resolution: 332 meters/pixel
Scale: Derain has a diameter of 167 km (104 miles)
Projection: simple cylindrical

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

Saturday, March 8, 2014

Odin Planitia and Schiaparelli Dorsum


On March 5 we saw an area to the west of Caloris. Today we travel to the east of the basin, another area that is thought to be related to ejecta from the Caloris basin impact event. The knobs and unusual corrugated texture are part of Odin Planitia and may have formed from ejecta and impact melt. Schiaparelli Dorsum, nearly aligned with the terminator (the division between the dayside and night side of the planet), cuts across the scene from top to bottom.

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: July 07, 2012
Image Mission Elapsed Time (MET): 250134169
Image ID: 2154159
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 24.83°
Center Longitude: 195.2° E
Resolution: 228 meters/pixel
Scale: This scene is approximately 400 km (250 miles) across
Incidence Angle: 88.8°
Emission Angle: 53.2°
Phase Angle: 142.0°

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

Thursday, March 6, 2014

Caloris Basin Rim


Small knobs and crater rims just barely catch the sunlight with the Sun low on Mercury's eastern horizon. The relatively smooth floor of the Caloris basin is on the right, and the rim and exterior of the basin are to the left. The knobby texture outside of the basin may be the result of blocks of material that were ejected by the basin-forming impact.

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: April 27, 2012
Image Mission Elapsed Time (MET): 244054579
Image ID: 1721895
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 40.19°
Center Longitude: 140.5° E
Resolution: 270 meters/pixel
Scale: This scene is approximately 492 km (306 miles) across
Incidence Angle: 88.2°
Emission Angle: 53.7°
Phase Angle: 142.0°

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

Tuesday, March 4, 2014

Abedin Crater Wall


The beautiful Abedin crater is featured in today's image. The crater's sunlit wall meets the crater floor, which occupies the left side of the scene. The floor is largely covered with rock that was melted by the Abdedin impact, ponded on the crater floor, and has now solidified, cracking as it cooled.

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

Date acquired: September 23, 2013
Image Mission Elapsed Time (MET): 22252071
Image ID: 4875876
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 62.28°
Center Longitude: 352.0° E
Resolution: 16 meters/pixel
Scale: Abedin crater is 116 km (72 miles) in diameter
Incidence Angle: 83.6°
Emission Angle: 22.1°
Phase Angle: 105.8°

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

Saturday, March 1, 2014

Graben from Pantheon Fossae


A series of troughs extends diagonally (southwest-northeast) across this high-resolution image of the interior of the Caloris basin. The troughs are graben: structures that developed where horizontal forces pulled the crust apart, causing valleys to form as sections of rock dropped down between two inward-dipping faults. Pulling-apart ("extensional") deformation is much less common on Mercury than is compressional deformation. However, a large number of graben are found within Caloris. This network of graben, named Pantheon Fossae, is the subject of a blog essay recently posted on the website of The Planetary Society.

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: January 19, 2012
Image Mission Elapsed Time (MET): 235472082
Image ID: 1285755
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 27.3°
Center Longitude: 160.7° E
Resolution: 24 meters/pixel
Scale: The scene is about 43 km (27 mi.) across
Incidence Angle: 76.8°
Emission Angle: 54.9°
Phase Angle: 131.8°
North is up in this image.

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