| Ultimi arrivi - Saturn: the "Ringed Beauty" and His Moons |
Janus-N00044715.jpgJanus and Epimetheus (3)58 visitenessun commentoDic 08, 2005
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Saturn-PIA07646.jpgThe limb of Saturn61 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".Dic 08, 2005
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Hyperion-PIA07768.jpg"Meri Crater"58 visiteSaturn's moon Hyperion's crater, Meri, blooms in this extreme color-enhanced view. Meri is overprinted by a couple of smaller craters and displays dark material on its floor that is characteristic of many impact sites on this moon. The walls of craters seen here are noticeably smoother on their sloping sides than around their craggy rims.
To create this false-color view, ultraviolet, green and infrared images were combined into a single black and white picture that isolates and maps regional color differences. This "color map" was then superimposed over a clear-filter image. The combination of color map and brightness image shows how the colors vary across the moon's surface in relation to geologic features.
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. The images used to create this false-color view were acquired on 09-26-2005, at a mean distance of 17.900 Km from Hyperion. Image scale is about 110 meters (360 feet) per pixel.Dic 08, 2005
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Rhea-PIA07765.jpgCraters, Slopes and Scarps on Rhea (HR)58 visiteCraters within craters cover the scarred face of Saturn's moon Rhea in this oblique, HR view of terrain on the moon's Western Hemisphere.
A large, degraded crater lies at the center, filled with rolling mounds and many smaller craters. A couple of linear depressions are visible in the terrain (especially at lower right), possibly marking tectonic faults. The crater is about 90 Km-wide (about 56-miles) and is located at 8,5° South Latitude and 154,9 West Longitude. The moon's icy regolith, or loose surface material, has likely been pummeled into a fine powder over the eons.
This is one of the highest-resolution images of Rhea's surface obtained during Cassini's close flyby on Nov. 26, 2005, during which the spacecraft swooped to within 500 Km of the large moon.
The clear filter image was acquired with the wide-angle camera at an altitude of approx. 620 Km above Rhea.
Image scale is about 85 mt (approx. 280 feet) per pixel.Dic 08, 2005
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Rhea-PIA07764.jpgRhea's "Ray Crater" (alias the "Great White Splat") and scarps from 511 Km58 visite(...) Cassini spacecraft snapped this image of the Eastern rim of Saturn's moon Rhea's bright, Ray Crater. The impact event appears to have made a prominent bright splotch on the Leading Hemisphere of Rhea. Because Cassini was traveling so fast relative to Rhea as the flyby occurred, the crater would have been out of the camera's field of view in any earlier or later exposure. The crater's total diameter is about 50 Km, but this rim view shows details of terrains both interior to the crater and outside its rim. The prominent bright scarp, left of the center, is the crater wall, and the crater interior is to the left of the scarp. The exterior of the crater (right of the scarp) is characterized by softly undulating topography and gentle swirl-like patterns that formed during the emplacement of the large crater's continuous blanket of ejecta material.
Numerous small craters conspicuously pepper the larger crater's floor and much of the area immediately outside of it. However, in some places, such as terrain in the top portion of the image and the bright crater wall, the terrain appears remarkably free of the small impacts. The localized "shot pattern" and non-uniform distribution of these small craters indicate that they are most likely secondary impacts -- craters formed from fallback material excavated from a nearby primary impact site. Because they exist both inside and outside the large crater in this image, the source impact of the secondary impacts must have happened more recently than the impact event that formed the large crater in this scene.Dic 08, 2005
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TheRings-G-Ring-PIA07643.jpgThe G-Ring's "Glow"58 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".Dic 02, 2005
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Enceladus-N00043480.jpgEnceladus, Rings and...photoartifact?87 visiteAttenzione: lo streak bianco che abbiamo evidenziato in questo frame è, con ogni probabilità, un artefatto fotografico. Questa immagine, tuttavia, ci serve per rammentare e rammentarVi che, nell'espressione di giudizi, teorie e/o sensazioni su quanto taluni frames mostrano (o sembrano mostrare), occorre usare sempre la massima cautela e la più grande prudenza, se si vuole rimanere credibili. Gli UFO, a nostro avviso, sono un argomento delicato ed importante che richiede, per essere analizzato in maniera adeguata, prudenza e competenza. In una parola: l'Ufologia è materia da trattare con estrema serietà ed attenzione.
Una serietà ed un'attenzione che, tuttavia, nei media e, ahinoi..., anche nella grande maggioranza degli Appassionati (Siti e Forum pieni di ufologi da strapazzo ce ne sono a migliaia), non si vede.Nov 30, 2005
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Epimetheus&Janus-N00043535.jpgJanus and Epimetheus (2)56 visiteN00043535.jpg was taken on November 29, 2005 and received on Earth November 29, 2005. The camera was pointing toward Epimetheus that, at the time, was approximately 1.103.937 Km away, and the image was taken using the CL1 and CL2 filters.Nov 30, 2005
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Epimetheus&Janus-N00043522.jpgJanus and Epimetheus (1)57 visiteN00043522.jpg was taken on November 29, 2005 and received on Earth November 29, 2005. The camera was pointing toward Epimetheus that, at the time, was approximately 1.095.193 Km away, and the image was taken using the CL1 and CL2 filters.Nov 30, 2005
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Enceladus-PIA07760.jpgThe "Fountains" of Enceladus58 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.
Nov 29, 2005
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Enceladus-PIA07759.jpgThe "Fountains" of Enceladus59 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...Nov 29, 2005
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Enceladus-PIA07758.jpgThe "Fountains" of Enceladus59 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. Nov 29, 2005
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