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| Piú votate - Mercury |
ZY-Mercury-PIA13840-PCF-LXTT.jpgCrescent Mercury (an Image-Mosaic by NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington - Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)104 visiteThis HR mosaic of NAC images shows Mercury as it appeared to MESSENGER as the Spacecraft departed the Planet following its first mission's Fly-By. This mosaic resembles the historic first image transmitted back to Earth after that Fly-By and shows a portion of the Planet never previously seen by Spacecrafts.
Date Acquired: January, 14th, 2008
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)MareKromium
(3 voti)
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ZZ-Mercury-Craters-Benoit_Crater-PIA12428.jpgBenoit Crater and Lange Basin (False Colors; credits: Dr Paolo C. Fienga - Lunexit Team)75 visiteThis NAC image, acquired during MESSENGER's 1st Mercury Fly-By, shows the Crater Benoit and the Lange Basin.
Benoit Craer has been so named in honor of Rigaud Benoit, a twentieth century Haitian painter (1911-1987), while the Lange Basin is in honor of the American photographer Dorothea Lange (1895-1965).
These particular Craters were proposed for names on the basis of some interesting features of each. Benoit is a small approx. 35-Km-diameter (about 22-mile-diameter) Crater, but its floor is quite unusual, with two mounds that have been suggested to be evidence of intrusive volcanic activity on Mercury.
The larger neighboring Lange Basin appears to have been flooded by lava, with only faint traces remaining of a now buried Inner Ring.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108828463
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 500 meters/pixel (0,31 miles)
Scale: Lange Basin is approx. 180 Km (about 112 miles) in diameter
Spacecraft Altitude: about 19.700 Km (approx. 12.200 miles)MareKromium
(3 voti)
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ZW-Mercury-PIA12397.jpgMercury76 visiteToday (December, 15th, 2009), the first High-Resolution Global Map of Mercury was made publicly available. Members of the MESSENGER team and experts from the U. S. Geological Survey (USGS) used images from MESSENGER's three Mercury flybys and from the Mariner 10 Mission in 1974-75 to create a Global Mosaic that covers 97,7% of Mercury's Surface at a resolution of 500 meters/pixel (0,31 miles/pixel).
The above image shows the full global Mercury mosaic but at a greatly reduced scale of only 5% of the HR version. The full HR mosaic by can be seen at the USGS Map-a-Planet website.
Date Mercury Fly-By 1: January 14, 2008
Date of Mercury Fly-By 2: October 6, 2008
Date of Mercury Fly-By 3: September 29, 2009
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: Mercury's diameter is approx. 4880 Km (such as about 3030 miles)MareKromium
(3 voti)
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ZZ-Mercury-Craters-Rembrandt_Crater-PIA12395.jpgLow Sun over Rembrandt Crater (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)63 visiteThis NAC image acquired during MESSENGER's third Fly-By of Mercury shows a view of the interior of Rembrandt Basin that emphasizes landforms. Rembrandt was discovered during the Mission's second Fly-By, in October 2008. Its large size (approx. 715 Km, or about 444 miles, in diameter), its relatively young age (as implied by the low number of superposed impact craters), and the radiating extensional and contractional fractures on its Floor, have made it a topic of special interest to the MESSENGER Science Team.
Earlier this year, an article devoted to the first study of the geology of Rembrandt was published in the Science magazine. During Mercury's Fly-By 3, Rembrandt was closer to the Terminator - such as the line between the sunlit dayside and dark nightside of the Planet - and the different viewing geometries between Fly-Bys 2 and 3 enabled a three-dimensional view of this unusual basin. The grazing angle of the light from the setting Sun in this particular NAC image accentuates the topography of the features on the Rembrandt's Floor, including the set of unusual Radiating Fractures.
Date Acquired: September 29, 2009
Image Mission Elapsed Time (MET): 162744327
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 390 meters/pixel (0,24 miles/pixel)
Scale: The prominent crater at center left is about 44 Km (approx. 27 miles) in diameter
Spacecraft Altitude (distance from target): approx. 15.100 Km (about 9400 miles)
MareKromium
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ZZ-Mercury-Craters-Unnamed_Double-Ring_Crater-PIA12368.jpgUnnamed Double-Ring Basin (Natural Colors; credits: Lunexit)72 visiteThis spectacular approx. 290-Km-diameter Double-Ring Basin seen in detail for the first time during MESSENGER's 3rd flyby of Mercury bears a striking resemblance to Raditladi Basin, observed during the 1st flyby.
This still-unnamed basin is remarkably well preserved and appears to have formed relatively recently, compared with most basins on Mercury. The low numbers of superposed impact craters and marked differences in color across the basin (seen in this enhanced color image released earlier this week) suggest that the smooth area within the innermost ring may be the site of some of the most recent volcanism on Mercury.
Date Acquired: September 29, 2009
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: This double-ring basin is approx. 290 Km (about 180 miles) in diameterMareKromium
(3 voti)
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ZZ-Mercury-Volcanic_Features-Vent-PIA12370.jpgIrregular Rimless Depression - Candidate for an Explosive Volcanic Vent on Mercury (Natural Colors; credits: Lunexit)63 visiteThis Region of high reflectance was just barely seen on the limb during MESSENGER's 2nd flyby, but without enough detail to characterize it as anything other than a bright spot.
A more favorable viewing angle reveals this bright spot to be an irregular rimless depression approx. 30 Km across surrounded by highly reflective material. Its features are distinctly different from those of impact craters and, though its origin remains ambiguous, it is suspected to be volcanic, possibly the site of an explosive Volcanic Vent. The high-reflectance halo surrounding this enigmatic feature is distinct in color and may represent a pyroclastic deposit greater than 150 Km in diameter.
Date Acquired: September 29, 2009
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: The irregular rimless depression in the center of the image is approx. 30 Km (about 19 miles) acrossMareKromium
(3 voti)
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ZZ-Mercury-Craters-Unnamed_Double-Ring_Basin.jpgDouble "Concentric" Basin on Mercury (Natural Colors; credits: Lunexit)63 visiteCaption NASA, da "NASA - Picture of the Day" del giorno 7 Ottobre 2009:"What created the internal second ring of this Double Ringed Basin on Mercury?
No one is sure.
The unusual feature spans approx. 160 Km and was imaged during the robotic MESSENGER Spacecraft's swing past our Solar System's innermost planet. Double and Multiple Ringed Basins, although rare, have also been imaged in years past on Mars, Venus, Earth and Earth's Moon.
Mercury itself has several doubles, including huge Caloris Basin, Rembrandt Basin and enigmatic Raditladi Basin. Most large circular features on planets and moons are caused initially by a forceful impact by a single asteroid or comet fragment. Since it is unlikely that a second impact would occur right in the center of the first, large double rings are usually attributed to a subsequent volcanic lava flow inside the impact crater.
Possibly, though, a second ring could be caused by the melting and flowing of material upon impact. One clue to the origin of the above-imaged double ring is that the basin center appears much smoother than the region between the rings. MESSENGER has now completed its last flyby of Mercury but will return and attempt to enter orbit in March 2011".MareKromium
(3 voti)
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ZZ-Mercury-Craters-Moody_Crater-PIA12044_fig1.jpgMoody Crater70 visiteThe crater identified in this NAC image was named in November 2008 for Ronald Moody, a 20th century Jamaican sculptor and painter (see PIA11762). Moody features a Central Peak or Peak-Ring structure and an Annulus of dark material on its Outer Floor (green arrows). The area inward of the dark ring appears reddish in enhanced color WAC images (see PIA11219), indicating the presence of material different in composition from that of either the dark material or the Crater's immediate surroundings. Dark material has been found associated with other craters on Mercury, including Munch and Poe (see PIA12034). Moody is somewhat unusual for having its dark ring confined to the Crater Floor, rather than forming the crater rim as at Munch and Poe.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108829034
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 590 meters/pixel (0,37 miles)
Scale: Moody is about 80 Km (approx. 50 miles) in diameter
Spacecraft Altitude: about 23.100 kilometers (approx. 14.300 miles)MareKromium
(3 voti)
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ZU-PIA12038.jpgIn search of the "Vulcanoids"63 visiteIn mid-February 2009, before and after MESSENGER's latest Perihelion (such as the closest approach to the Sun), an imaging campaign was conducted to search for "Vulcanoids": small rocky bodies that have been postulated to exist in orbits between Mercury and the Sun. Those images are still waiting to be transmitted to Earth.
The image here is from the first set of 240 MDIS images taken to look for vulcanoids, acquired in June 2008. It is a 10" exposure taken through the WAC's clear filter. Jupiter is bright and visible in the image. The camera field of view is nearly large enough to capture the entire width of Sagittarius, a constellation of the Zodiac visible low and to the South in Summer from temperate latitudes in the Northern Hemisphere. The Greek letters identify some of the brighter stars in Sagittarius.
During the Vulcanoid search campaign, 4-5 images of the same scene are taken back to back. This procedure allows Cosmic Ray strikes on the camera's detector to be identified and enables fainter objects to be detected. One such Cosmic Ray strike is labeled on this image. In this single image, the Cosmic Ray strike appears similar to the stars, but in the 4 images taken immediately after this one, the Cosmic Ray strike is gone whereas the stars remain. Images are also taken hours and days apart, so the motion of objects in the sky can be determined. If a Vulcanoid were imaged, its motion through the sky would appear very different from motions of the background stars and known Solar System objects.
No Vulcanoids have been found yet, but the latest set of acquired images will expand the volume of the search region examined so far.
Date Acquired: June 4, 2008
Image Mission Elapsed Time (MET): 121050477
Instrument: Wide Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
WAC Filter: 2 (clear filter)
Field of View: The WAC has a 10,5° field of viewMareKromium
(3 voti)
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ZU-PIA12051.jpgGlobal Map of Mercury76 visiteMESSENGER's two flybys of Mercury in 2008 have greatly increased the portion of the Planet's Surface that has been imaged by spacecraft, from approximately 45% coverage obtained by Mariner 10 to about 90% coverage following the second flyby.
This significant increase in imaging coverage is enabling global studies of Mercury's Surface for the first time. MESSENGER team members recently published an article in the 1st of May issue of the "Science" Magazine that utilizes this new global view to examine the evolution of Mercury's crust. This recent work was also featured in a NASA media teleconference, and the top image shown here was presented during that teleconference.
Both images are orthographic map projections of Mercury created with WAC enhanced-color images. The orthographic projection produces a view that has the perspective that one would see from deep space. The WAC enhanced color uses a statistical analysis of images from all 11 WAC filters to highlight subtle differences in the crustal rocks on Mercury's Surface. For other examples and discussion of enhanced color images, see previous releases of the departure view from Mercury flyby 2, Rudaki Plains, Thakur Crater and Caloris Basin.
The top view uses images from Mercury flyby 1, with the thin crescent of Mercury imaged during approach forming the right portion of the globe and the fuller departure view showing Caloris Basin forming the left side and majority of the view.
The black strip between the approach and departure images is a portion of Mercury's Surface not viewed by MESSENGER during the flybys. Similarly, the approach and departure images obtained during Mercury flyby 2 yielded the bottom view.
The top and bottom projections are centered on 180° and 0° Longitude, respectively.
Date Acquired: January 14, 2008, and October 6, 2008
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Scale: Mercury’s diameter is about 4880 Km (approx. 3030 miles)MareKromium
(3 voti)
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ZZ-Mercury-Craters-Munch_Crater_et_al_-PIA12034_fig1.jpgMunch, Sander and Poe Crater64 visiteSander, Munch and Poe are a trio of impact craters within the Caloris Impact Basin (see PIA10359).
Munch and Poe were recently named (see PIA11762), while Sander received its name in the first set of feature names (see PIA10611) after MESSENGER’s first Mercury flyby. Munch is named for Edvard Munch (1863-1944), the Norwegian artist and painter of "The Scream".
The crater Poe takes its name from Edgar Allan Poe, the 19th century American writer and poet.
Sander is named for the German photographer August Sander (1876-1964).
Sander Crater exhibits very bright material within its Rim, while Munch and Poe each are surrounded by dark material. The presence of both bright and dark materials suggest that there is a diversity of rock types on and below Mercury's Surface, with different mineralogical compositions from those of the volcanic plains that comprise the majority of the floor of Caloris Basin.
The 3 Craters are located in the far northern part of the Caloris Basin. The basin Rim (see PIA10942), indicated by yellow arrows, can be seen in the upper left and extending across the top of this image, and many fractures within Caloris Basin (see PIA10606) are visible in the lower portion of this image.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108828587
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 520 meters/pixel (0,32 miles/pixel)
Scale: This image is about 550 Km (approx. 340 miles) across
Spacecraft Altitude: about 20.400 Km (approx. 12.400 miles)MareKromium
(3 voti)
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ZZ-Mercury-Global_View_of_the_Surface-PIA11795_fig1.jpgVarious Mercurian Surface Features (natural colors; credits: Lunar Explorer Italia)73 visiteThis NAC image displays a number of interesting geologic features characteristic of Mercury’s Surface.
The Crater indicated by the yellow arrow has unusual bright material on its floor, likely due to rocks of a different chemical composition. Bright material also has been seen in the craters Sander and Kertész.
The pink arrows point to a pair of larger and older craters that have been flooded with now solidified volcanic lava, similar to flooding seen at the impact basin Raphael. In the lower right-hand corner of the image is a large peak-ring Basin, about 210 Km (approx. 130 miles) in diameter, which also appears to have been flooded with lava. There is also a small Scarp (or "Cliff") within that Basin that cuts through a smaller crater at the edge of the Basin's inner ring, at the point indicated by the blue arrow.
Scarps on Mercury are often seen intersecting Impact Craters, such as this dramatic, previously released image from the mission's second Mercury flyby (see, for example, PIA11358).
The green arrows on the left side of the image indicate a series of Secondary Crater Chains. Chains of small craters such as these are formed when ejecta are expelled from a Primary Crater after the initial impact. Secondaries are widespread across Mercury's Surface, as was also discussed in the caption to this previously released image (see PIA10178).
Unraveling Mercury's Geologic History requires investigating the complex and overlapping relationships of Volcanic Plains, Impacts and Scarps seen on the Planet's Surface.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774026
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 540 meters/pixel (0,33 miles/pixel)
Scale: This image is about 550 Km (approx. 340 miles) across
Spacecraft Altitude: about 21.000 Km (approx. 13.000 miles)MareKromium
(3 voti)
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