Saturn: the "Ringed Beauty" and His Moons
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Dione-N00119795.jpgCross-Worlds! (11)53 visitenessun commentoMareKromium
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Dione-N00154016-17-19-EB-LXTT.jpgDione (Natural Colors; credits for the additional process. and color.: Elisabetta Bonora - Lunexit Team)82 visitenessun commentoMareKromium
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Dione-N00160857-60-EB-LXTT.jpgJust a "Slice" of Dione (Superdefinition and Natural Colors; credits for the additional process. and color.: Elisabetta Bonora - Lunexit Team)64 visitenessun commentoMareKromium
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Dione-N00165580-82-EB-LXTT.jpgPossible Transient Luminous Phenomenon on the "Dark Side" of Dione144 visiteLa Natura del piccolo "flash" individuato nelle Regioni Equatoriali di Dione, è bene dirlo a chiare lettere, non può essere in alcun modo stabilita con certezza.
Dall'analisi di dettaglio del frame, comunque, possiamo estrapolare alcune ipotesi, che Vi elenchiamo in ordine di fondatezza/verosimiglianza (a nostro parere, come ovvio):
1) Bagliore da Impatto Meteorico - Meteor Strike's related/caused Flash;
2) Fiaccola di origine ignota (magari un outgassing?) - Flare of unknown origin (l'equivalente Dioniano di un TLP);
3) Artefatto Fotografico da perdita di segnale - image artifact due to lack of signal;
4) Artefatto Fotografico a causa indeterminata - image artifact due to an undetermined cause .MareKromium
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Dione-N00165585-89-EB-LXTT.jpgCrescent Dione (an Image-Mosaic by Elisabetta Bonora - Lunexit Team)126 visitenessun commentoMareKromium
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Dione-N00199629-33-EB-MF-LXTT-IPF.jpgThe Many faces of Dione (Superdefinition and Natural Colors; credits for the additional process. and color.: Elisabetta Bonora and Marco Faccin/Lunar Explorer Italia/Italian Planetary Foundation)173 visiteThe Icy Surface of the Saturnian moon Dione includes, among other things, some Heavily Cratered Terrain, Moderately Cratered Plains, Lightly Cratered Plains, and several Areas which show the presence of deep and wide Tectonic Fractures (notice that all these Geological Features are well visible in this beautiful picture). The Heavily Cratered Terrain shows a number of Impact Craters which are larger than 100 Km (a little more than 62 miles) in diameter. The Plain Areas, on the other hand, tend to have Impact Craters which are less than 30 Km (such as about 18,6 miles) in diameter. Some of the Plains, however, are more Heavily Cratered than others. Much of the Heavily Cratered Terrain is located on the Trailing Hemisphere of Dione, while the less Cratered Plains are found on the Leading one.
This characteristic of Dione tells us just the opposite of what a few scientists would have expected; Shoemaker and Wolfe, for instance, proposed a Cratering Model for a Tidally Locked Satellite with the highest Cratering Rates on its Leading Hemisphere and the lowest ones on the Trailing Hemisphere. This Model, therefore (if it is one-hundred-percent correct - a fact, this one, that we have no way to prove with absolute cetainty), suggests that during the period of heavy bombardment, Dione was (better yet: could have been) tidally locked to Saturn in an opposite orientation as to the present one. Just because Dione is a relatively small Celestial Body (approx. 1120 Km - such as about 695,5 miles - in diameter), we can assume that an impact causing an approx. 35-Km-diameter Impact Crater should have been strong enough to alter the Course (---> Motion and Orientation) of the moon, as to its Parent Planet. Now, since there are so many Impact Craters on Dione which are way larger than 35 Km (such as about 21,7 miles), we can logically speculate that Dione itself might have changed both its Motion and Orientation a few times during the aforementioned period of heavy bombardment. Eventually, once that the bombardment ended, the moon was finally able to set itself on a definitive and stable Course around Saturn.
As a matter of fact, the Pattern of Cratering and the bright Albedo of its Leading Side suggest that Dione has remained in its current Course for several billion years. Like the Jovian moon Callisto, Dione's Impact Craters lack the high Central Features (---> Peaks/Uplifts) that are often seen, instead, on the Moon and Mercury; this circumstance, in our opinion, is probably due to slumping (---> Mass Wasting) of the weak Icy Crust over Geologic Times, but a final answer to this kind of question, as you can imagine, will probably never given with an absolute certainty. Just out of curiosity, if you pay special attention to the visible portion of the Limb of Dione, as it appears in this highly defined picture, you may realize that its shape is NOT, in fact, perfectly spherical.
This image, which is a combination of 5 (five) Original NASA - CASSINI Spacecraft b/w frames whose ID numbers are N00199629/30/31/32 and 33, has been additionally processed and then colorized in Natural Colors (such as the colors that a perfect human eye - or an Electronic Eye - would have perceived while looking at Dione from Cassini's vantage point) by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Dione, each having a different Albedo (---> Reflectivity) and Chemical Composition. MareKromium
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Dione-N160934-48-EB-LXTT.jpgDione (an Image-Mosaic in RAW Natural Colors by Elisabetta Bonora - Lunexit Team)61 visitenessun commentoMareKromium
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Dione-N160934-48-EB-PCF-LXTT.jpgDione (an Image-Mosaic in Absolute Natural Colors by Elisabetta Bonora - Lunexit Team)61 visitenessun commentoMareKromium
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Dione-NVL-MF-PCF-LXTT.jpgDione (an Image-Mosaic in Absolute Natural Colors by Marco Faccin and Paolo C. Fienga - Lunexit Team)128 visitenessun commentoMareKromium
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Dione-PIA06155-1.jpgDione and Saturn in natural colors78 visiteCaption NASA originale:"Cassini captured Dione against the globe of Saturn as it approached the icy moon for its close rendezvous on Dec. 14, 2004. This natural color view shows the moon has strong variations in brightness across its surface, but a remarkable lack of color, compared to the warm hues of Saturn's atmosphere. Several oval-shaped storms are present in the planet's atmosphere, along with ripples and waves in the cloud bands.
The images used to create this view were obtained with the Cassini spacecraft wide-angle camera at a distance of approximately 603.000 Km from Dione through a filter sensitive to wavelengths of ultraviolet light centered at 338 nanometers. The Sun-Dione-spacecraft, or phase, angle is 34°. The image scale is about 32 Km per pixel".
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Dione-PIA06156_modest.jpgDione: close-up (1) - HR59 visiteCaption NASA originale:"This incredible, HR view of Saturn's moon Dione was taken during Cassini's first close approach to the icy moon on Dec. 14, 2004. The view shows linear, curving features within the region of the bright wispy terrain Dione is known for.
The image was obtained in visible light with the Cassini spacecraft narrow angle camera at a distance of approximately 156.000 Km (97.000 miles) from Dione. The Sun-Dione-spacecraft, or phase, angle is 34°. The image scale is about 1 Km (0.6 miles) per pixel".
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Dione-PIA06163.jpgDione: close-up (2) - HR53 visiteCaption NASA originale:"This very detailed image taken during the Cassini spacecraft's closest approach to Saturn's moon Dione on Dec. 14, 2004 is centered on the wispy terrain of the moon. To the surprise of Cassini imaging scientists, the wispy terrain does not consist of thick ice deposits, but rather the bright ice cliffs created by tectonic fractures". Una nostra piccola annotazione: tutta la superficie di Dione è, a ben vedere, un mosaico di quelle che alla NASA chiamano "tectonic fractures"; ma guardate bene che cosa si diparte, circa al centro dell'immagine, dalla linea del terminatore: una "frattura tettonica anomala", perfettamente dritta, curiosamente molto luminosa (ci ricorda una pista di atterraggio/decollo di aeromobili oppure un'autostrada...) che attraversa altre fratture (decisamente più "naturali"...) e che costeggia il bordo di almeno 5 crateri, uno dei quali ci sembra abbastanza grande. Se non la vedete, guardate il detail mgnf che abbiamo preparato per Voi nel frame successivo.
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