| Risultati della ricerca nelle immagini - "moon" |
Amalthea-PIA01076.jpgAmalthea and a few inner Moons of Jupiter79 visiteChe cosa distingue questi "macigni vaganti" dalla maggior parte delle Lune di Giove?
Si tratta di Lune originarie del Sistema Gioviano o sono state "attratte" da Giove, durante un passaggio troppo ravvicinato?
Probabilmente si tratta di asteroidi vaganti o di comete mancate: oggetti provenienti dalla Fascia di Kuiper (KBO) che, in transito accanto al Gigante Gassoso, si sono trovati all'angolo ed alla velocità corretti per non essere né semplicemente deflessi dalla loro corsa e quindi scagliati via nello spazio interstellare, né per finire frammentai (Limite di Roche) od attratti ed ingurgitati definitivamente da Giove, come è invece accaduto alla Cometa Shoemaker-Levy.
Molti Scienziati non escludono neppure l'ipotesi che possa trattarsi di frammenti di una Luna Gioviana disintegratasi (magari a seguito di una collisione) qualche milione di anni fa.
La verità, come sempre, non sarà facile da trovarsi.
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Amalthea-PIA02532.jpgA white streak on Amalthea76 visitenessun commento
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Callisto-Asgard emi.-Gal-PIA00562_modest.jpgThe "Asgard" hemisphere of Callisto (detail mgnf)73 visiteCaption NASA originale:"...Dominating the scene is the impact structure, Asgard, centered on the smooth, bright region near the middle of the picture and surrounded by concentric rings up to 1.700 kilometers in diameter. A second ringed structure with a diameter of about 500 kilometers can be seen to the north of Asgard, partially obscured by the more recent, bright-rayed crater, Burr. The icy materials excavated by the younger craters contrast sharply with the darker and redder coatings on older surfaces of this Moon..."
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Callisto-Asgard emisph.-Gal-PIA01100_modest.jpgThe "Asgard" hemisphere of Callisto65 visiteCaption NASA originale:"False color view of a portion of the leading hemisphere of Jupiter's moon Callisto as seen through the infrared filters of the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. North is to the top of the picture and the sun illuminates the surface from the east. More recent impacts have excavated bright, relatively clean ice from beneath Callisto's battered surface. Callisto's dark mottled appearance may be due to contamination by non-ice components contributed by impactors or concentrated in a residue as ice is removed".
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Callisto-Chain of craters-PIA00514_modest.jpgA chain of craters on Callisto106 visiteCaption NASA originale:"A portion of a chain of impact craters on Jupiter's moon Callisto is seen in this image taken by the Galileo spacecraft on November 4, 1996. This crater chain on Callisto is believed to result from the impact of a split object, similar to the fragments of Comet Shoemaker-Levy 9 which smashed into Jupiter's atmosphere in July of 1994".
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Callisto-V1-PIA00362_modest.jpgCallisto from 1.200.000 Km (Voyager 1)67 visiteCaption NASA originale:"This color photo of Jupiter's satellite Callisto was made from three black-and-white images taken March 5 from a distance of 746.000 miles (1,2 MKMs).
It shows the entire hemisphere of Callisto that was photographed at HR by Voyager 1 during the close encounter with the satellite. Visible near the upper left limb is the large basin-like structure discovered by Voyager 1. The central region of the basin is much brighter than the average surface of the satellite. Near the south polar region are two bright areas associated with smaller basin-like structures. These bright areas are believed to contain more clean ice than the rest of Callisto's generally 'dirty-ice' surface".
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Callisto-V1-PIA02277_modest.jpgCallisto's basin from Voyager 167 visiteCaption NASA originale:"This picture of a multi=ring basin on Callisto was taken the morning of March 6, 1979, from a distance of about 200.000 Km. The complicated circular structure seen at left center is similar to the large circular impact basins that dominate the surface of the Earth's moon and also the planet Mercury. The inner parts of these basins are generally surrounded by radially lineated ejecta and several concentric mountainous ring structures that are thought to form during the impact event. This multi-ring basin on Callisto consists of light floored central basin some 300 k m in diameter surrounded by at least eight to ten discontinuous rhythmically spaced ridges. No radially lineated ejecta can be seen. The ring structures on Moon and Mercury have been likened to ripples produced on a pond by a rock striking the water. The great number of rings observed around this basin on Callisto is consistent with its low planetary density and probable low internal strength".
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Callisto-full disk-PIA03456_modest.jpgCallisto from Galileo98 visiteCaption NASA originale:"Bright scars on a darker surface testify to a long history of impacts on Jupiter's moon Callisto in this image of Callisto from NASA's Galileo spacecraft.
The picture, taken in May 2001, is the only complete global color image of Callisto obtained by Galileo, which has been orbiting Jupiter since December 1995. Of Jupiter's four largest moons, Callisto orbits farthest from the giant planet.
Callisto's surface is uniformly cratered but is not uniform in color or brightness. Scientists believe the brighter areas are mainly ice and the darker areas are highly eroded, ice-poor material".
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Europa,_Io_and_Jupiter.jpgOver the "Eye"134 visiteNice frame.MareKromium
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Europa-Chaotic_Terrain-Conamara_Chaos-PIA01181.jpgConamara Chaos Region on Europa (HR)81 visiteThis view of the Conamara Chaos region on Jupiter's moon Europa shows cliffs along the edges of high-standing ice plates. The washboard texture of the older terrain has been broken into plates which are separated by material with a jumbled texture. The cliffs themselves are rough and broadly scalloped, and smooth debris shed from the cliff faces is piled along the base. For scale, the height of the cliffs and size of the scalloped indentations are comparable to the famous cliff face of Mount Rushmore in South Dakota.
This image was taken on December 16, 1997 at a range of 900 Km (540 miles) by the Solid State Imaging System Camera on Galileo spacecraft. North is to the top right of the picture and the sun illuminates the surface from the east. This image, centered at approx. 8 North Latitude and 273 West Longitude, covers an area approx. 1,5 by 4 Km (about 0,9 by 2,4 miles). The resolution is 9 mt (30 feet) per picture element.
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Europa-Crater_and_Ridges.jpgPwyil Crater - Europa149 visiteThe large Jovian moon Europa may harbor liquid water beneath its frozen crust. Controversy surrounding this idea has been recently fueled by dramatic images of Europa's surface from the Galileo spacecraft.
This alluring color image was produced by combining low resolution color data with higher resolution mosaics recorded during three separate flybys and covers about 120 by 150 miles.
The eerie terrain of grooved linear ridges and crustal plates which seem to have broken apart and rafted into new positions could indicate subsurface water or slush. Blue tints represent relatively old ice surfaces while reddish regions may contain material from more recent internal geological activity.
White splotches are bright material blasted from the young impact crater Pwyll located about 600 miles south (to the right) of this area.
Many believe that large reservoirs of water hold out the tantalizing possibility of organisms living on this dim, distant world.MareKromium
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