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| Piú votate - Mercury |
ZZ-Mercury-Limb-CN0131766564M.pngA Small Crater Makes a Bright Impact (natural colors; credits: Lunexit)77 visiteDate Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766564
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 410 meters/pixel (0,25 miles/pixel) in the lower right corner of the image
Scale: The bright crater is about 30 Km in diameter (approx. 19 miles)
Spacecraft Altitude: about 16.000 Km (about 9900 miles)
Of Interest: In both the optical navigation images and the full-planet Wide Angle Camera (WAC) approach frame, a bright feature is clearly visible in the northern portion of the crescent-shaped Mercury. This NAC image resolves details of this bright feature, showing that it surrounds a small crater about 30 Km (approx. 19 miles) in diameter, seen nearly edge-on. Presumably, the bright material was ejected from this small crater, which apparently formed relatively recently in Mercury’s past, because Mercury’s surface materials tend to darken with time. The brilliant ejecta are so bright compared with the neighboring surface that Earth-based telescopic observations also detected this feature, despite its being associated with such a small crater.MareKromium
(4 voti)
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ZZ-Mercury-Rupes-CN0131773865_web.pngAstrolabe Rupes (natural colors; credits: Lunexit)89 visiteDate Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774936
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 660 meters/pixel (0,41 miles/pixel)
Scale: Ghiberti crater is approx. 123 Km in diameter (about 76 miles)
Spacecraft Altitude: about 26.000 Km (approx. 16.000 miles)
Of Interest: This NAC image, taken about 85 minutes after MESSENGER’s closest approach during the mission’s second Mercury flyby, shows a view of Astrolabe Rupes, named for the ship of the French explorer Jules Dumont d’Urville. Rupes is the Latin word for cliff. Mercury’s day/night transition (the Terminator) is located on the left side of the image, and the Sun is striking the cliff face of Astrolabe Rupes in the upper right of the image. Also visible in the image are additional unnamed rupes, whose cliff faces are casting dark shadows. One of these rupes intersects the crater Ghiberti, named for the Italian Renaissance sculptor. Rupes on Mercury are thought to have formed as the interior of Mercury cooled and the planet consequently contracted slightly. Determining the number and extent of rupes on Mercury can thus be used to understand the thermal history of the Planet.MareKromium
(4 voti)
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ZZ-Mercury-Craters-Sveinsdottir_Crater-PIA11078.jpgSveinsdóttir Crater in 3D74 visiteThis graphic shows a portion of the fault scarp Beagle Rupes cutting through the highly elliptical crater Sveinsdóttir in a three-dimensional (3D) representation.
By combining information from multiple images of the same portion of Mercury's surface taken under different viewing angles, the topography of the surface was determined. A high-resolution image was then overlaid on the topography map, resulting in this 3D image.
In total, over 80 MESSENGER images were used to create this 3D view of Mercury's surface.
As the MESSENGER mission continues, many more images will be acquired, and these additional images will provide views of Mercury's surface from a variety of illumination conditions and viewing geometries. These myriad views, anchored by topographic profiles to be acquired by MESSENGER's laser altimeter, will enable large portions of the surface of Mercury to be studied in 3D.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET) : NAC image from 108830230 resampled on a topographic map made from more than 80 NAC and WAC images.
Instrument: Narrow Angle Camera (NAC) and Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Scale: Sveinsdóttir Crater is about 120 by 220 Km (approx. 75 by 140 miles). MareKromium
(4 voti)
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ZS-Mercury-PIA11077.jpgFaults in Caloris Basin64 visiteAs the youngest large impact basin known on Mercury, the Caloris Basin has landforms that are better preserved than in older basins, which have been more modified by impact cratering.
This figure, recently published in Science magazine, shows a map of many linear features within Caloris Basin that formed when the near-surface rocks were subjected to large horizontal forces. The Caloris Basin contains hundreds of extensional troughs, mapped as black lines, where the surface has been pulled apart and faulted.
Pantheon Fossae (located inside the white box of the top map and shown in detail in the bottom image) has over 200 such troughs in a radiating pattern, but near the outer edges of the basin interior troughs are seen in patterns broadly concentric to Caloris Basin. The Caloris Basin interior also has been deformed by many wrinkle ridges, mapped as red lines, formed when the surface was compressed or shortened horizontally. Relationships between the extensional troughs and contractional wrinkle ridges provide information about the evolution of the Caloris basin and Mercury's interior.
Date Acquired: January 14, 2008
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: Caloris Basin is about 1550 Km (approx. 960 miles) in diameter. The crater Apollodorus near the center of Pantheon Fossae is about 41 Km (approx. 25 miles) in diameter. MareKromium
(4 voti)
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ZQ-Mercury-PIA10942.jpgShield-Volcano on Mercury65 visiteAs reported in the July 4, 2008 issue of Science magazine, volcanoes have been discovered on Mercury’s Surface from images acquired during MESSENGER’s first Mercury flyby. This image shows the largest feature identified as a volcano in the upper center of the scene. The volcano has a central kidney-shaped depression, which is the vent, and a broad smooth dome surrounding the vent. The volcano is located just inside the rim of the Caloris Impact Basin. The rim of the Basin is marked with hills and mountains, as visible in this image. The role of volcanism in Mercury’s history had been previously debated, but MESSENGER’s discovery of the first identified volcanoes on Mercury’s surface shows that volcanism was active in the distant past on the innermost Planet.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET:108826877
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 270 meters/pixel (0,17 miles/pixel)
Scale: This image is about 270 Km across (approx. 170 miles)
Spacecraft Altitude: approx. 10.500 Km (about 6500 miles)MareKromium
(4 voti)
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ZQ-Mercury-PIA10984.jpgCraters "Deformed" and "Shortened" on Mercury65 visiteNumerous examples of craters that have been deformed and shortened by younger faults have been identified on images returned from MESSENGER’s first flyby of Mercury. In three cases shown here (arrows), portions of the floor and rim of a crater were buried when a large block of crust was thrust over the crater during the formation of a prominent fault scarp or cliff. By comparing the estimated size and shape of the original, undeformed crater with the crater’s current geometry, scientists can infer the amount of movement between the two crustal blocks on either side of the fault. This figure was recently published in Science magazine.
For each of the three examples of deformed and shortened craters shown here, movement on the faults buried at least a kilometer of the original crater. A: 17-Km (11-mile) diameter crater (arrows) shortened by Beagle Rupes. B: 5-Km (3-mile) diameter crater deformed near the rim of an older, larger crater, shown enlarged in the box on the lower left. C: 11-Km (7-mile) diameter crater (arrows) shortened by a North/West-South/East-trending fault scarp.MareKromium
(4 voti)
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ZZ-Mercury-Craters-Kertész_Crater-PIA10933.jpgKertész Crater (Saturated Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)60 visiteLocated in the Western Edge of Mercury's giant Caloris Basin, Kertész Crater (recently named for André Kertész, a Hungarian-born American photographer) has some unusual, bright material located on its floor. Sander crater, located in the North-Western Edge of Caloris Basin, also shows bright material on its floor.
The MESSENGER Science Team is investigating the nature and composition of these bright materials and making comparisons between these two craters both located at the edges of Caloris Basin.
Just North-East of Kertész, a small crater has very bright rays and ejecta in this image, indicating that the crater is young.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108826812
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 260 meters/pixel (0,16 miles/pixel
Scale: Kertész Crater is about 34 Km (approx. 21 miles) in diameter
Spacecraft Altitude: about 10.200 Km (approx. 6.340 miles)MareKromium
(4 voti)
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ZZ-Mercury-Limb-PIA10359.jpgCaloris Basin (natural colors; credits: Lunexit)60 visiteThis natural-color image of Mercury shows the great Caloris Impact Basin (see also PIA10383), visible in this image as a large, circular feature in the center of the picture. The contrast between the colors of the Caloris Basin Floor and those of the surrounding plains indicate that the composition of Mercury's surface is variable. Many additional geological features with intriguing color signatures can be identified in this image. For example, the bright spots just inside the rim of Caloris Basin are thought to mark the location of Volcanic Features, such as the volcano shown in this previously released Narrow Angle Camera (NAC) image PIA10942.
MESSENGER Science Team members are studying these regional color variations in detail, to determine the different mineral compositions of Mercury's surface and to understand the geologic processes that have acted on it. (...)
Date Acquired: January 14, 2008
Image Mission Elapsed Times (MET): 108827278-108827328
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Resolution: about 2,3 Km (approx. 1,4 miles/pixel)
Scale: Caloris Basin is about 1550 Km in diameter (approx. 960 miles)
Spacecraft Altitude: approx. 13.000 Km (about 8000 miles)MareKromium
(4 voti)
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ZQ-Mercury-PIA10611.jpgNew Names for Features on Mercury63 visiteThe International Astronomical Union (IAU) recently approved new names for features on Mercury that were all seen for the first time in images taken by MESSENGER during the Spacecraft's first flyby of the Planet.
Read the full press release for additional details about the naming process and the origin of the names, and visit the U.S.G.S. website, the Gazetteer of Planetary Nomenclature, to learn about all of the named planetary features in the Solar System.
This image, produced by mosaicking many Narrow Angle Camera (NAC) images together, shows the locations of the newly named features, along with the craters Basho, Mozart, and Tolstoj, first seen by the Mariner 10 Mission.
Close-up views of many of these features are available in the MESSENGER website image gallery. In particular, look at these previous releases for NAC high-resolution images of Apollodorus, Beagle Rupes, Eminescu, Mozart, Neruda, Pantheon Fossae, Raditladi and Sander.MareKromium
(4 voti)
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ZZ-Mercury-Limb-PIA10938.jpgMercury’s Craters from a New Perspective61 visiteAs MESSENGER approached Mercury, the NAC acquired images to create a mosaic of the entire Planet. The mosaic shown here was created from about half of those images and is shown in an orthographic projection. This view is in contrast to the cylindrical equidistant map mosaic previously released. For this mosaic, an orthographic projection was used to create a view that has the perspective that one would see from deep space. Over three decades earlier, Mariner 10 viewed this portion of Mercury’s Surface, and the craters that were named on the basis of those images are labeled on this mosaic.
The MESSENGER images of this same territory are allowing scientists to study Mercury’s surface under different illumination conditions, and these complementary views provide new insight into the nature of the geologic features on Mercury.
Date Acquired: January 14, 2008
Instrument:Mosaic created with images taken by the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 1,5 Km/pixel (0,93 miles/pixel)
Scale: this mosaic shows Mercury from the Equator nearly to the North Pole, a distance of about one Mercury radius (2440 Km, such as approx. 1516 miles)MareKromium
(4 voti)
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ZP-Mercury-PIA10379.jpgMESSENGER Flies through Mercury's Magnetosphere64 visiteCaption NASA:"This picture shows a conceptual sketch of Mercury's Magnetosphere at the time of the MESSENGER flyby. The graphs at the bottom show observations made by the Fast Imaging Plasma Spectrometer (FIPS) portion of the Energetic Particle and Plasma Spectrometer (EPPS) instrument as the Spacecraft followed the indicated trajectory. The top plot depicts the low-energy plasma of solar wind origin, and the bottom plot shows heavy ion intensities associated with the Planet.
This flyby was the first survey of the ion plasma of Mercury's space environment. The positions at which the Spacecraft first crossed the "bow shock" of the magnetospheric interaction with the Solar Wind, passed closest approach to the Planet, and crossed the outbound bow-shock crossing are indicated.
These results show the expected increases in Solar Wind Plasma density downstream of the bow-shock boundary, as well as significant Solar Wind Plasma densities within Mercury's Magnetosphere close to the Planet. The latter measurements provide definitive evidence that Mercury's Magnetosphere — despite its small size — is not a vacuum but hosts significant densities of heated Solar Wind pPasma. The plasma affects the Magnetic Field, contributes to the "space weathering" of the Planet's Surface, and sputters material from the surface to populate the Exosphere. This first detection of heavy pick-up ions, Na+ and other species, near Mercury is consistent with their production by ionization of exospheric neutral species.
This complex system and all of its time variations will be studied during the next two MESSENGER flybys as well as throughout the orbital phase of the Mission".MareKromium
(4 voti)
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ZP-Mercury-PIA10380.jpgMercury's Internal Magnetic Field92 visiteCaption NASA:"This depiction of a simulated Mercury Magnetosphere shows representations of the distortions of the Planetary Magnetic Field Lines (blue) by the Solar Wind. Mariner 10 data showed the first evidence for a Magnetic Field at Mercury, an unexpected result. The equatorial pass of MESSENGER during quiet solar conditions provided better data than were available from Mariner 10.
MESSENGER saw an Internal Magnetic Field that is well described by the field from a dipole nearly aligned with the Planet's Spin Axis (dipole tilt ~ 10°). This geometry is similar to that observed by Mariner 10 during its first flyby. The field strength is weaker by about one third than that detected by Mariner 10 during its third (and last) flyby, owing primarily to the difference in trajectories (Mariner 10 flow directly over the magnetic pole where the field strength is greatest). When corrected for our best estimate for the external field, the MESSENGER observations and the two Mariner 10 passes are consistent with very similar solutions for the mean Planetary Magnetic Dipole. The Dipolar Field is consistent with an active electrical dynamo in which the magnetic field is produced by electrical currents flowing in an outer core of molten metal.
The observations do not yet allow us to identify whether a small secular variation may have occurred, determine higher order structure in the field, or assess whether crustal magnetic signatures may be present at other longitudes.
A combination of the next two flybys and the orbital phase of MESSENGER's mission will be required to sort out all of these possible effects".MareKromium
(4 voti)
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