| Piú viste - Saturn: the "Ringed Beauty" and His Moons |
Rhea-N00043397.jpgSteep Scarps, Craters and Peaks57 visiteN00043397.jpg was taken on November 26, 2005 and received on Earth November 27, 2005. The camera was pointing toward Rhea that, at the time, was approximately 65.083 Km away.
The image was taken using the CL1 and GRN filters.
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Rhea-N00043395.jpgLittle "White Rayed Splat"57 visiteN00043395.jpg was taken on November 26, 2005 and received on Earth November 27, 2005. The camera was pointing toward Rhea that, at the time, was approximately 65.528 Km away.
The image was taken using the CL1 and CL2 filters.
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Rhea-N00043370.jpgThe limb of Rhea57 visiteN00043370.jpg was taken on November 26, 2005 and received on Earth November 27, 2005. The camera was pointing toward Rhea that, at the time, was approximately 71.771 Km away.
The image was taken using the CL1 and IR3 filters.
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Rhea-N00043364.jpgThe limb of Rhea and the Rings57 visiteN00043364.jpg was taken on November 26, 2005 and received on Earth November 27, 2005. The camera was pointing toward Rhea that, at the time, was approximately 73.117 Km away.
The image was taken using the CL1 and UV3 filters.
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Enceladus-PIA07758.jpgThe "Fountains" of Enceladus57 visiteRecent Cassini images of Saturn's moon Enceladus backlit by the sun show the fountain-like sources of the fine spray of material that towers over the South Polar Region. This image was taken looking more or less broadside at the "tiger stripe" fractures observed in earlier Enceladus images. It shows discrete plumes of a variety of apparent sizes above the limb of the moon.
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Enceladus-PIA07759.jpgThe "Fountains" of Enceladus57 visite"...this greatly enhanced and colorized image shows the enormous extent of the fainter, larger-scale component of the plume..."
Nota: dal tenore del commento NASA, oltre ad una leggera sorpresa, non pare trasparire alcunchè. Allora: se abbiamo capito bene c'è qualcosa che viene "spruzzato" nel cielo dalla superficie di Encelado e che forma una sorta di "fontana" di corpuscoli che si disperdono nello spazio.
Qualcosa di incredibile e di assolutamente "alieno" (nel senso di lontano dal nostro modo di vedere e di immaginare le cose) sta accadendo, ma la NASA si limita a darci un commentino secco e asciutto, come la risposta ad un quesito di Scienze Planetarie che verrebbe data al Professore da uno studente non troppo preparato. Abbiamo letto, recentemente, della costante caduta di interesse da parte dell'opinione pubblica in generale e dei giovani in particolare verso lo Spazio e l'esplorazione del Sistema Solare. Onestamente, visto l'atteggiamento costantemente bolso di ESA e NASA, non ce ne meravigliamo...
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Enceladus-PIA07760.jpgThe "Fountains" of Enceladus57 visiteA fine spray of small, icy particles emanating from the warm, geologically unique province surrounding the South Pole of Enceladus was observed in a Cassini narrow-angle camera image of the crescent moon taken on Jan. 16, 2005. Taken from a high phase angle of 148° - a viewing geometry in which small particles become much easier to see - the plume of material becomes more apparent in images processed to enhance faint signals.
Imaging scientists have measured the light scattered by the plume's particles to determine their abundance and fall-off with height. Though the measurements of particle abundance are more certain within 100 Km of the surface, the values measured there are roughly consistent with the abundance of water ice particles made by other Cassini instruments (reported in 09/2005) at altitudes as high as 400 Km above the surface.
At present, it is not clear if the plume particles emanating from the south pole arises because of water vapor escaping from warm ice that is exposed to the surface. Another possibility is that at some depth beneath the surface, the temperatures are hot enough for water to become liquid, which then, under pressure, escapes to the surface like a cold Yellowstone geyser.
The image at the left was taken in visible green light. A dark mask was applied to the moon's bright limb to make the plume feature easier to see.
The image at the right has been color-coded to make faint signals in the plume more apparent. Images of other moons, such as Tethys and Mimas, taken in the last 10 months from similar lighting and viewing geometries, and with identical camera parameters, were closely examined to demonstrate that the plume towering above Enceladus' south pole is real and not a camera artifact.
The images were acquired at a distance of about 209,400 kilometers (130,100 miles) from Enceladus. Image scale is about 1 kilometer (0.6 mile) per pixel.
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TheRings-G-Ring-PIA07643.jpgThe G-Ring's "Glow"57 visiteOriginal caption:"Saturn's G-Ring glows like a neon garland in this lovely narrow angle camera image from Cassini. The comparison between the diffuse outer boundary and the sharp inner edge of this Ring, which consists of fine, dust-sized icy particles, is particularly noteworthy. Close Cassini views such as this should provide Ring scientists with clues about how this Ring is produced and confined.
The G-Ring extends from 166.000 to 173.200 Km (about 103.100 to 107.600 miles) from Saturn's center. (remember: Saturn is 120.500 Km [about 74.900 miles] wide at its equator).
The image was taken in visible light with the Cassini narrow-angle camera on Oct. 24, 2005, at a distance of approx. 2,1 MKM (about 1,3 MMs) from Saturn. The image scale is 12 Km (about 8 miles) per pixel".
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Saturn-PIA07646.jpgThe limb of Saturn57 visiteOriginal caption:"This brooding portrait shows the South-Western limb of the cold gas giant and the thread-like cloud features lurking there. The limb appears smooth, but at the terminator (such as the boundary between light and dark) and at higher resolution, variations in cloud height can cause shadows that are visible to Cassini.
The image was taken in visible, red light with the Cassini spacecraft wide-angle camera on Oct. 30, 2005, at a distance of approx. 401.000 Km(such as about 249.000 miles) from Saturn and at a phase angle of 155°. Image scale is 20 Km (13 miles) per pixel. The image was contrast enhanced to improve visibility of features in the atmosphere".
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Janus-N00044721.jpgJanus and Epimetheus (4)57 visitenessun commento
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Saturn-N00044405.jpgPhotographic Defect, Photo-Artifact or UFO in-transit? (3)57 visitevedi il commento al frame precedente
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The Rings & Rhea-PIA07655.jpgThe F-Ring and crescent Rhea57 visiteThe searing arc of light seen here is Saturn's icy F-Ring, seen nearly edge-on. In the background, Rhea is lit by reflected light from Saturn and the Rings, with only the slightest sliver of light at its bottom being from direct Sunlight.
The faint material surrounding the F-Ring likely lies in the Planet's equatorial plane, extending radially farther out and in from the main F-Ring core.
A smaller fraction of this material could be vertically extended, and Cassini's investigations should help to clarify this.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Oct. 30, 2005, at a distance of approximately 689.000 Km (about 428.000 miles) from Saturn. The image scale is approximately 4 Km (2 miles) per pixel.
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