| Piú viste - Mercury |
ZZ-Mercury-Craters-Crater_Cluster-208907.jpgCraterland62 visiteMESSENGER's Narrow Angle Camera (NAC) on the Mercury Dual Imaging System (MDIS) acquired this view of Mercury’s surface illuminated obliquely from the right by the Sun. The unnamed crater (about 52 Km in diameter) in the center of the image displays a telephone-shaped collapse feature on its floor.
Such a collapse feature, not seen on the floors of other craters in this image, could reflect past volcanic activity at and just below the surface of this particular crater.
The crater is located in the Southern Hemisphere of Mercury, on the side that was not viewed by Mariner 10 during any of its three flybys (1974-1975).
This scene was imaged while MESSENGER was departing from Mercury from a distance of 19.300 Km (approx. 12.000 miles), about 1 hour after the spacecraft's closest encounter with Mercury.
The image is of a region approx. 236 Km (about 147 miles) across, and craters as small as 1,6 Km (1 mile) can be seen. MareKromium
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ZZ-Mercury-Craters-Unnamed_Rayed_Crater-209510.jpgRayed Crater on Mercury62 visiteJust above and to the left of center of this image is a small crater with a pronounced set of bright rays extending across Mercury's surface away from the crater. Bright rays are commonly made in a crater-forming explosion when an asteroid strikes the surface of an airless body like the Moon or Mercury. But rays fade with time as tiny meteoroids and particles from the Solar Wind strike the surface and darken the rays. The prominence of these rays implies that the small crater at the center of the ray pattern formed comparatively recently.
This image is 1 in a planned set of 99. Nine different views of Mercury were snapped in this set to create a mosaic pattern with images in 3 rows and 3 columns. The WAC is equipped with 11 narrow-band color filters, and each of the 9 different views was acquired through all 11 filters. This image was taken in filter 7, which is sensitive to light near the red end of the visible spectrum (750 nm), and shows features as small as about 6 Km (about 4 miles) in size.
The MESSENGER team is studying this previously unseen side of Mercury in detail to map and identify new geologic features and to construct the Planet’s geological history.
Mission Elapsed Time (MET) of image: 108827618MareKromium
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ZZ-Mercury-Limb-PIA10936.jpgDürer Basin (natural colors; credits: Lunexit)62 visiteMESSENGER snapped this image of Mercury’s horizon about 56 minutes before the Spacecraft’s closest pass by the Planet. The distinctive peak-ring basin Dürer (named from Mariner 10 photos for the German artist Albrecht Dürer) is visible.
The smaller crater Mickiewicz (named for the Polish poet Adam Mickiewicz) can also be seen, with a smaller central peak-ring structure in the middle of its crater floor.
Craters form ring structures during the impact process that creates the crater, and the number and characteristics of the rings depend on the crater’s size. Raditladi, imaged for the first time by MESSENGER and recently named, also shows a pronounced peak-ring structure.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108821505
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: Dürer crater is about 190 Km (approx. 120 miles) in diameter
Spacecraft Altitude: about 18.300 Km (approx. 11.400 miles)MareKromium
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ZZ-Mercury-Limb-PIA12047.jpgMercurian Limb with Rembrandt Basin (Natural Colors; credits: Lunar Explorer Italia)62 visiteThis mosaic was assembled using NAC images acquired as the MESSENGER spacecraft approached the Planet during the mission's second Mercury flyby. The Rembrandt Impact Basin is seen at the center of the mosaic, as night was falling across the Basin's Eastern Edge. An image similar to this one appears on the cover of the 1st of May issue of the "Science" magazine, which contains four articles on the latest results from that flyby. Click here to view more materials presented during a NASA media teleconference about these latest findings.
Date Acquired: October 6, 2008
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: Rembrandt Basin is approx. 715 Km (about 444 miles) in diameterMareKromium
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ZZ-Mercury-Scarp-PIA12054.jpgLong and High Scarp (Natural Colors; credits: Lunar Explorer Italia)62 visiteThe Scarp cutting through this Unnamed Crater was imaged as MESSENGER approached the Planet during the mission's second Mercury flyby. The full NAC image acquired by MDIS is shown in a previous release (see PIA11772) while the image shown here is a reprojected view. Compare the two images to see the differences.
By using very precise knowledge about the time that the image was taken and the location of the Spacecraft at that time, the original image can be mapped onto a globe of Mercury. Once mapped onto a Mercury globe, that globe can be viewed in many different ways, including reprojections that create flat maps of Mercury's Surface, as seen in the Global Map of Mercury (see PIA11403). The reprojected image shown here is from a simple cylindrical map projection. Map projections are needed to measure accurately the extent of features on the surface. For example, from this reprojection it was determined that this Scarp is about 1 Km (0,6 miles) high and over 160 Km (about 100 miles) in length. MESSENGER Science Team members recently published an image similar to this reprojection in Science magazine.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766501
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 420 meters/pixel (0,26 miles)
Scale: This crater is about 200 Km (about 124 miles) in diameter
Spacecraft Altitude: 16.300 Km (about 10.100 miles)MareKromium
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ZZ-Mercury-Craters-Raditladi_Impact_Basin-PIA12042_fig1.jpgRaditladi Basin62 visiteRaditladi Basin, imaged during MESSENGER's first Mercury flyby and named in April 2008 (PIA10611), is intriguing for several reasons. Shown extending across the top of this high-resolution NAC image, Raditladi Basin is relatively young, with only a few small impact craters on its floor and with well-preserved walls and peak-ring structure.
Visible on the floor of Raditladi are concentric troughs (blue arrows), formed by extension (pulling apart) of the surface. However, extensional troughs on Mercury are quite rare, having been seen to date only in two other locations on the Planet: as part of Pantheon Fossae and other troughs in Caloris Basin and on the floor of Rembrandt, the large basin discovered during MESSENGER's second Mercury flyby (see PIA11769).
Understanding how these troughs formed in the young Raditladi Basin could provide an important indicator of processes that acted relatively recently in Mercury’s geologic history.
Raditladi Basin was the topic of one of 25 presentations made by MESSENGER team members at the 40th Lunar and Planetary Science Conference held last week (April 2009).
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108826792
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 250 meters/pixel (0,16 miles/pixel)
Scale: Raditladi basin has a diameter of approx. 257 Km (about 160 miles)
Spacecraft Altitude: approx. 10.000 Km (about 6200 miles)MareKromium
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ZZ-Mercury-Craters-Vyasa_and_Stravinsky_Crater-PIA12035_fig1.jpgLow-Sun over Mercury...62 visiteThis NAC image shows a close-up view of the craters Vyasa and Stravinsky (see PIA11360). Stravinsky is the smooth-floored crater partially seen on the right side of the image that overlies the rim of the larger, rougher crater Vyasa in the center and left. The low-Sun lighting angle casts distinctive shadows that show Mercury's rough surface, pockmarked by craters of all sizes. Small craters are visible on the smooth-floor of Stravinsky because of the high resolution of this image.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131771118
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 140 meters/pixel (0,09 miles/pixel) near the bottom of the image
Scale: Stravinsky crater is about 190 Km in diameter (120 miles)MareKromium
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ZZ-Mercury-Craters-Lermontov_Crater-PIA12116.jpgLermontov Crater (possible Natural Colors; credits: Lunar Explorer Italia)62 visiteLermontov Crater was first observed by Mariner 10 and seen more recently by MESSENGER during its second flyby of Mercury. The Crater fFloor is somewhat brighter than the exterior surface and is smooth with several irregularly shaped depressions.
Such features, similar to those found on the floor of Praxiteles Crater (see PIA12040), may be evidence of past explosive volcanic activity on the Crater Floor. Lermontov appears reddish in enhanced-color views (see PIA11411), suggesting that it has a different composition from the surrounding surface.
Lermontov is named for Mikhail Yurevich Lermontov, a nineteenth-century Russian poet and painter who died from a gunshot suffered in a duel.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131771953
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 250 meters/pixel (0,16 miles/pixel)
Scale: Lermontov’s diameter is about 152 Km (approx. 94 miles)
Spacecraft Altitude: about 10.000 Km (approx. 6200 miles)
Nota Lunexit: curiosamente, dopo il nostro Color Processing, non è Lermontov ad apparire "rossiccio", a fronte di terreni circostanti grigiastri, bensì l'esatto contrario! Curioso...MareKromium
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ZZ-Mercury-Craters-Tiziano_Crater-PIA12079.jpgTitian Crater (extremely enhanced Natural Colors; credits: NASA and Lunar Explorer Italia)62 visiteThis enhanced-color image shows Titian Crater (center) and is similar to an image that recently appeared in the 1st of May 2009 issue of Science magazine.
The enhanced-color view was created by using high-resolution images taken in all 11 WAC filers (one of which is shown in a previously released image, see PIA11765) and comparing and contrasting them to accentuate differences on Mercury’s Surface. Such color differences can be used to learn about the history of Mercury’s Surface in this area. In the enhanced color, the smooth floor of Titian is a brighter orange color than the surrounding area, likely due to being filled with volcanic material. Ejecta from Titian appear blueish and cover much of the Surface surrounding the Crater. This material was excavated from depth during the Crater’s formation.
Later impacts, such as the one that produced the small crater that appears yellowish in the upper center of the image, excavated material from below the Titian ejecta. This yellow-appearing material was present at or near the surface before the impact that created Titian and is a different composition (and thus, color) from its surroundings. Impacts make it possible to assess how Mercury’s Crust varies with depth and ultimately how the crust evolved through time.
Date Acquired: October 6, 2008
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 462 meters/pixel (0,29 miles/pixel)
Scale: Titian crater is about 121 Km (approx. 75 miles) in diameter
Nota Lunexit: curiosa la "chiazza violacea" visibile ad ore 01:00 del Cratere "Tiziano". La NASA, ovviamente, ha commentato tutto, tranne il dettaglio più intrigante. Noi, purtroppo, non possiamo aggiungere nulla, se non ribadire un concetto già espresso dalla NASA più volte, e cioè che "a colore diverso, nei frames colorizzati in natural enhanced colors, corrisponde un materiale diverso". Nulla di più.MareKromium
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Mercury 1.jpgMercury photo-mosaic from Mariner 1061 visite...sarà di gran lunga maggiore (a livello previsionale e sulla base delle stime fatte sulla Terra, sperimentalmente) di quanto non lo sarebbe stata se la parte rocciosa di Mercurio si fosse invece venuta a trovare connessa indissolubilmente ad un nucleo esterno totalmente ghiacciato e solidificato (ossìa con il mantello, il nucleo esterno ed il nucleo interno del Pianeta UNITI a formare un "pezzo unico").
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B-Mercury-PIA02946.jpgCraters on the morning terminator...61 visiteCaption NASA originale:"As Mariner 10 passed by Mercury on its second encounter with the planet on September 21, 1974, this picture (FDS 166850) of a large circular (350 Km - or 220 mile diameter) basin was obtained near the morning terminator. The basin appears to have been flooded with the plain material and then subsequently cratered by numerous large events. Filling of the basin, presumably by lava flows analogous to those of the lunar maria, partially inundated small craters which had formed along the basin rim (lower left) and in some places overflowed the basin rim and spilled onto the surrounding terrain (top)".
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B-Mercury-PIA02939.jpgDark-rimmed crater and extensive "Ejecta Blanket"61 visiteCaption NASA originale:"Mariner 10 took this picture (FDS 166840) from a distance of 63.400 Km (39.300 miles) about one hour after it passed under the South Pole of Mercury. The dark-rimmed crater at upper left is 67 Km (42 miles) in diameter. It is surrounded by an extensive ejecta blanket and exhibits a bright ray pattern, which extends into and beyond the larger crater (120 Km - or 75 miles) to its right and near the picture's center. The dark-rimmed crater is similar to crater Tycho on Earth's moon. The center of this picture is located 33° South Lat. and 158° West Long. North is to the top".
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