| Piú votate - Saturn: the "Ringed Beauty" and His Moons |
Saturn-N00063521-00.jpgIncredible "Meteor" (?) strikes the upper layers of Saturn's atmosphere (context image)85 visiteUn frame, questa volta davvero incredibile (inserire Saturn-N00063521-00) e, riteniamo, di straordinario valore, ci arriva - in data 7 Luglio 2006 - dallo Spazio di Saturno per mostrare un lungo "streak in the sky": una Scia Luminosa che attraversa quasi la totalità del campo visivo di una delle fotocamere poste a bordo della Sonda Cassini.
Circa due anni fa, avevamo già rilevato uno "streak" similare il quale, in due frames Cassini consecutivi, aveva attraversato una modesta porzione del campo visivo di una delle telecamere della Sonda (ben visibili, sullo sfondo dell'immagine ed oltre alla Striscia Luminosa, anche alcune stelle ed i segni del transito di qualche raggio cosmico.
Oggi, 7 Luglio 2006, lo streak è diverso: questa volta non si tratta di una luce fissa in (lento?) movimento nello spazio; adesso lo streak, come potrete meglio valutare Voi stessi nei detail magnifications di cui ai frames 2 e 3, appare diretto verso le profondità di Saturno - il frame Cassini originale, infatti, raffigura il lato notturno del Gigante Anellato.
Di che cosa si può trattare?
Questa volta, dopo aver esperito le analisi del caso, abbiamo una teoria.
(8 voti)
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The Rings-PIA06175_modest.jpgThe Rings (full view) in natural colors54 visiteCaption NASA originale:"Saturn's most prominent feature, its dazzling Ring System, takes center stage in this stunning natural color mosaic which reveals the color and diversity present in this wonder of the Solar System. Gaps, gravitational resonances and wave patterns are all present and the delicate color variations across the System are clearly visible.
This mosaic of 6 images covers a distance of approximately 62.000 Km along the ring plane, from a radius of 74.565 Km to 136.780 Km from the Planet's center.
This view is from Cassini's vantage point beneath the ring plane. The rings are tilted away from Cassini at an angle of about 4°.
Images taken using red, green and blue spectral filters were used to create this natural color mosaic. The images were acquired using the Cassini spacecraft narrow angle camera on Dec. 12, 2004, at a distance of approximately 1,8 MKM (1,1 MMs).
The image scale is 10,5 Km per pixel".
(8 voti)
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Telesto-PIA07696.jpgTelesto55 visiteThese views show surface features and color variation on the Trojan moon Telesto. The smooth surface of this moon suggests that, like Pandora, it is covered with a mantle of fine, dust-sized icy material.
This monochrome image was taken in visible light. To create the false-color view (see PIA07697), ultraviolet, green and infrared images were combined into a single black and white picture that isolates and maps regional color differences.
The "color map" was then superposed over a clear-filter image. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy soil.
Tiny Telesto is a mere 24 Km (about 15 miles) wide.
The image was acquired with the Cassini spacecraft narrow-angle camera on Dec. 25, 2005 at a distance of approx. 20.000 Km (about 12.000 miles) from Telesto and at a Sun-Telesto-spacecraft, or phase, angle of 58°. Image scale is 118 meters (387 feet) per pixel.
(8 voti)
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Telesto-N00047273.jpgTelesto55 visiteOriginal caption:"N00047273.jpg was taken on December 25, 2005 and received on Earth December 26, 2005. The camera was pointing toward TELESTO that, at the time, was approximately 21.404 kilometers away, and the image was taken using the CL1 and CL2 filters".
Nota: secondo Voi è il movimento della Sonda rispetto a Cassini che ha determinato il repentino cambio di posizione di Telesto in questi due frames, oppure Telesto è un'altra - vera, questa volta! - "Tumbling Moon" (al pari - presunto - di Hyperion)?!?
(8 voti)
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Japetus-PIA07660.jpgLand of the Day, Land of the Night57 visiteAlthough it is no longer "Uncharted Land", the origin of the dark territory of Cassini Regio on Iapetus remains a mystery.
Also puzzling is the equatorial ridge that bisects this terrain, and how it fits into the story of the moon's strange brightness dichotomy. The ridge is seen here, curving along the lower left edge of Iapetus.
The view looks down onto the Northern Hemisphere of Iapetus, and shows terrain on the moon's Leading Hemisphere.
The image was taken in polarized green light with the Cassini spacecraft narrow-angle camera on Nov. 12, 2005 at a distance of approx. 417.000 Km (such as about 259.000 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 95°. Image scale is about 2 Km (about 1 mile) per pixel.
(8 voti)
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Dione&Tethys-PIA07630.jpgThe Eternal Companions54 visiteOriginal caption:"The moons Dione and Tethys face each other across the gulf of Saturn's Rings. Here, the Cassini spacecraft looks on the Saturn-facing Hemisphere of Tethys below and the anti-Saturn side of Dione above. The dark groove in the Rings is the Cassini Division.
This image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 22, 2005, at a distance of approximately 860.000 Km (about 530.000 miles) from Dione. Tethys was on the far side of the rings, 1,5 MKM (roughly 900.000 miles) from Cassini. The image scale is 5 Km (about 3 miles) per pixel on Dione and 9 Km (about 6 miles) per pixel on Tethys".
(8 voti)
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Pandora-N00042203.jpgPandora and...?54 visiteOriginal caption:"N00042203.jpg was taken on October 29, 2005 and received on Earth October 30, 2005. The camera was pointing toward PANDORA at approximately 459.147 Km away, and the image was taken using the CL1 and UV3 filters. This image has not been validated or calibrated".
(8 voti)
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Prometheus&Pandora-PIA07612.jpgCosmic race: Prometheus and Pandora73 visiteSaturn's moon Prometheus (Sx) chases Pandora (Dx) in this Cassini view, but the outcome of their race has already been decided by gravity. Prometheus orbits closer to Saturn and thus moves faster than does Pandora. This view is from a third of a degree (1/3°) beneath the Ringplane. Familiar Ring features that are visible from higher angles above the Rings are foreshortened here. The Planet's dark shadow stretches across the Ringplane at center.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 8, 2005, at a distance of approx. 1,8 MKM (such as about 1,1 MMs) from Saturn. The image scale is 10 Km (about 6 miles) per pixel on Prometheus and Pandora.
(8 voti)
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Dione-PIA07747.jpgDione (full view - false colors)54 visiteNon sappiamo se siamo stati sufficientemente chiari sulla delicatissima tematica che abbiamo cercato di affrontare, sebbene solo per sommi capi. Ciò che conta, in ultima analisi, è non uccidere l'immaginazione e, con essa, la capacità di meravigliarsi davanti a qualcosa che supera (per definizione) i confini dello Spazio e del Tempo: lo studio dell'Astronomia e dell'Astrofisica, una volta eliminata la componente "immaginifica" che è propria di queste Scienze, rischia di diventare - sempre a nostro parere - uno studio fine a se stesso.
Coniugare l'armonia delle cosiddette "Meccaniche Celesti" a qualcosa di più vicino alla nostra Natura Umana, invece, potrebbe permetterci di arrivare davvero - in un futuro - a "vedere" qualcosa di più ed a "capire" qualcosa di più.
Ma forse questa visione è solo una nostra "fantasia". Le Vostre opinioni al riguardo, ad ogni modo, saranno bene accette.
(8 voti)
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Prometheus-PIA07601.jpgPrometheus leaves a "dark track" inside the F-Ring62 visiteOriginal caption:"Prometheus poses here with its latest creation: a dark, diagonal gore (---> incisione/striscia) in the tenuous material interior to Saturn's F-Ring. The shepherd moon creates a new gore each time it comes closest to the F-Ring while the memory of previous passes is preserved in the Rings' structure for some time afterward. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 20, 2005, at a distance of approx. 499.000 Km (about 310.000 miles) from Saturn and at a very high phase angle, such as 144°.
Resolution in the original image was 3 Km about 2 miles) per pixel".
(8 voti)
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Hyperion-PIA07740.jpgHyperion - false colors58 visiteOriginal caption:"This stunning false-color view of Hyperion reveals crisp details across the strange, tumbling moon's surface. Differences in color could represent differences in the composition of surface materials. The view was obtained during Cassini's close flyby on Sept. 26, 2005.
Hyperion has a notably reddish tint when viewed in natural color. The red color was toned down in this false-color view and the other hues were enhanced, in order to make more subtle color variations across Hyperion's surface more apparent.
Images taken using infrared, green and ultraviolet spectral filters were combined to create this view. The images were taken with the Cassini spacecraft's narrow-angle camera at a distance of approx. 62.000 Km (about 38.500 miles) from Hyperion and at a Sun-Hyperion-spacecraft angle of 52°.
The image scale is 362 mt (about 1200 feet) per pixel".
(8 voti)
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Hyperion-PIA07741-3.jpgHyperion's unusual craters (3) - HR55 visiteUn piccolo applauso a Lunar Explorer Italia la quale, con due giorni e mezzo di anticipo sulla NASA (Commenti Ufficiali), è riuscita ad individuare ed estrapolare, dall'analisi dei "raw frames Cassini" - usando gli occhi dei Ricercatori e qualche altro mezzo informatico davvero "povero"... - le tematiche di maggiore interesse che riguardano questa piccola Luna Saturniana e che la NASA stessa ha, come avete letto nelle note di commento - "original caption" - ai due frames precedenti, enfaticamente portato all'attenzione dei Lettori.
Un "Bravo" a Lunar Explorer Italia quindi (...che ogni tanto lo meritiamo davvero...).
(8 voti)
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