Jupiter: the "King" and His Moons
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JUPITER LIGHTNINGS.jpgJupiter's lightninghs80 visitenessun commento
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JUPITER_S_RINGS-00.jpgJupiter's rings125 visiteIl profilo di Giove non ci mostra i suoi colori così come invece era avvenuto nell'immagine precedente, ma l'immagine è comunque bella e spettacolare, nonchè interessante: lo vedete il "gap" negli Anelli di Giove che spicca a ridosso del disco del Pianeta, sulla Sx dell'Osservatore?
Si tratta, come ovvio, di un semplice effetto ottico causato dalla particolare prospettiva dalla quale la ripresa è stata effettuata: è l'ombra stessa di Giove, infatti, a "cancellare" una porzione del sottile filo di detriti cosmici che forma il Sistema Anulare del Gigante Gassoso.
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IO - TRUE COLOR FROM GALILEO.jpgIo in true colors84 visiteNASA's Galileo spacecraft acquired its highest resolution images of Jupiter's moon Io on 3 July 1999 during its closest pass to Io since orbit insertion in late 1995. This color mosaic uses the near-infrared, green and violet filters (slightly more than the visible range) of the spacecraft's camera and approximates what the human eye would see. Most of Io's surface has pastel colors, punctuated by black, brown, green, orange, and red units near the active volcanic centers. A false color version of the mosaic has been created to enhance the contrast of the color variations.
The improved resolution reveals small-scale color units which had not been recognized previously and which suggest that the lavas and sulfurous deposits are composed of complex mixtures (Cutout A of false color image). Some of the bright (whitish), high-latitude (near the top and bottom) deposits have an ethereal quality like a transparent covering of frost (Cutout B of false color image). Bright red areas were seen previously only as diffuse deposits. However, they are now seen to exist as both diffuse deposits and sharp linear features like fissures (Cutout C of false color image). Some volcanic centers have bright and colorful flows, perhaps due to flows of sulfur rather than silicate lava (Cutout D of false color image). In this region bright, white material can also be seen to emanate from linear rifts and cliffs.
Comparison of this image to previous Galileo images reveals many changes due to the ongoing volcanic activity.
Galileo will make two close passes of Io beginning in October of this year. Most of the high-resolution targets for these flybys are seen on the hemisphere shown here.
North is to the top of the picture and the sun illuminates the surface from almost directly behind the spacecraft. This illumination geometry is good for imaging color variations, but poor for imaging topographic shading. However, some topographic shading can be seen here due to the combination of relatively high resolution (1.3 kilometers or 0.8 miles per picture element) and the rugged topography over parts of Io. The image is centered at 0.3 degrees north latitude and 137.5 degrees west longitude. The resolution is 1.3 kilometers (0.8 miles) per picture element. The images were taken on 3 July 1999 at a range of about 130,000 kilometers (81,000 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its twenty-first orbit.
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Jupitercrescent_cassini_big.jpgJupiter from Cassini65 visiteLa "falce" di un Giove crescente, ripresa dalla Sonda Cassini mentre si avvicinava e si apprestava ad effettuare il "fly-by" del Gigante Gassoso.
Una splendida immagine che ci ricorda alcune sequenze del capolavoro di Stanley Kubrick, "2001 - A Space Odyssey" in cui Giove appariva agli occhi di Dave Bowman proprio come lo vediamo in questo frame.
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Jupiter, Europa & Callisto.jpgJupiter, Europa and Callistus57 visitenessun commento
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JUPITER from 10,1 MKM.jpgJupiter from 10,1 MKM84 visitePadre degli Dei e Signore incontrastato del Sistema Solare; troppo grande per essere solo un pianeta, ma troppo piccolo per diventare una stella. Con la sua luce giallo-arancio illumina i nostri cieli durante la notte ed è, assieme a Venere, uno dei primi astri ad essere visibile verso l'imbrunire ed è l'unico corpo celeste che può essere visto ad occhio nudo (sapendo dove guardare...) anche durante il giorno.
Questo è Giove.
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JUPITER from 77,6 MKM.jpgJupiter from 77,6 MKM55 visiteDid you know that the "Planet With The Shortest Day" is Jupiter?
The planet Jupiter has the shortest day of all the nine major planets in the Solar System: it spins around on its axis once every 9 hrs 55 mins and 29,69 secs. Jupiter is about five times further from the Sun than the Earth and so it's years are much longer than Earth years: Jupiter completes one "year" in 4.332,6 Earth days. Jupiter is also one of the brightest objects in the night sky (jointly with the star Syrius and planet Venus in our Northern Hemisphere and with the Alpha and Beta Centauri star system in the Southern Hemisphere).
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JUPITER from 81,3 MKM.jpgJupiter from 81,3 MKM54 visitenessun commento
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JUPITER from 84,1 MKM.jpgJupiter from 84,1 MKM54 visitenessun commento
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Himalia from 4,4MKM.jpgHimalia from 4,4 MKM65 visiteCassini spacecraft captured images of Himalia, the brightest of Jupiter's outer moons, on Dec. 19, 2000, from a distance of 4,4 MKM.
This near-infrared image, with a resolution of about 27 Km (such as roughly 17 miles) per pixel, indicates that the side of Himalia facing the spacecraft is ,ore or less 160 Km (about 100 miles) in the up-down direction. Himalia probably has a non-spherical shape. Scientists believe it is a body captured into orbit around Jupiter, most likely an irregularly shaped asteroid. In the main frame, an arrow indicates Himalia. North is up. The inset shows the little moon magnified by a factor of 10, plus a graphic indicating Himalia's size and the direction of lighting (with sunlight coming from the left). Cassini's pictures of Himalia were taken during a brief period when Cassini's attitude was stabilized by thrusters instead of by a steadier reaction-wheel system. No spacecraft or telescope had previously shown any of Jupiter's outer moons as more than a "star-like" single dot.
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IO 8.jpgIo from 8,3 MKM!69 visiteThis photo of Jupiter's satellite Io was taken by Voyager 1 about 4:30 p.m. (PST) March 2, 1979. The spacecraft was about 5 million miles (8.3 million kilometers away). Voyager 1 was mapping Jupiter with the cameras and infrared instrument at the time the picture was taken. The hemisphere seen here is the one that always faces away from Jupiter. This photo shows details on Io never before seen. The smallest features are about 38 miles (70 kilometers) across. Near the center and slightly to the right can be seen several round features with dark centers and bright rims. They may be the first craters ever observed on Io. At this resolution scientists still cannot tell much about the origin of the features, which could be impact craters or of internal (volcanic) origin. No ray or ejecta patterns are obvious at this resolution.
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IO 7.jpgIo & Jupiter (from Voyager 2)65 visiteUn'immagine da guardare in parallelo ad un altro "transito" di Io davanti a Giove: questo è un frame (eccezionale!) Voyager 2; il precedente, come ricorderete, era un frame Cassini. Tecnologicamente parlando, c'è un "abisso" tra la Sonda Voyager e la Sonda Cassini ma, alla prova delle immagini, i risultati "visivi" ottenuti sono sostanzialmente analoghi. E questa è un'altra ragione della nostra diffidenza nei confronti della NASA (e dell'ESA): se negli Anni '70 ed '80 eravamo già capaci di simili risultati, come mai oggi, AD 2005, non siamo neppure in grado di dire quali sìano i veri colori e le vere (da un punto di vista dell'occhio umano) "sfumature" di Marte, Giove e Saturno? Eravamo bravissimi 25 anni fa e "stupidi" adesso, oppure non avevamo capito niente 25 anni fa mentre ora tutto e chiaro (si fa per dire)? O forse NON c'è stata reale "evoluzione" da un punto di vista tecnologico? O magari la "Verità" è così incredibile che divulgarla è ritenuto periglioso?
Domande: sempre domande...
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