Jupiter: the "King" and His Moons
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Io-flares and eruptions-PIA02254.jpgFlares and Eruptions on the limb of crescent Io107 visiteUn frame da ricordare, per bellezza ed importanza: ecco come appaiono le "flares" sul bordo di un pianeta in ombra. Sappiamo, in questo caso, che si tratta di eruzioni ed outgassing in corso e nessuno ne dubita. Tuttavia, quando fenomeni similari (o identici) vengono osservati sulla Luna, tutti (o quasi) gli Scienziati ed i Ricercatori si affrettano a dire che non possibile e che deve trattarsi di sviste o bagliori da impatto. Ma perch fa cos paura l'idea che la Luna possa essere ancora in parte "viva"?
Voyager 2 took this picture of Io July 10, 1979, from a range of 1.2 million kilometers (750,000 miles). It was one of the last of an extensive sequence of "volcano watch" pictures planned as a time lapse study of the nearest of Jupiter's Galilean satellites. The sunlit crescent of Io is seen at the left, and the night side illuminated by light reflected from Jupiter can also be seen. Three volcanic eruption plumes are visible on the limb. All three were previously seen by Voyager 1. On the bright limb Plume 5 (upper) and Plume 6 (lower) are about 100 kilometers high, while Plume 2 on the dark limb is about 185 kilometers high and 325 kilometers wide. The dimensions of Plume 2 are about 1 1/2 times greater than during the Voyager 1 encounter, indicating that the intensity of the eruptions has increased during the four-month time interval between the Voyager encounters. The three volcanic eruptions and at least three others have apparently been active at roughly the same intensity or greater for a period of at least four months.
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Io-hot spots-PIA02589_modest.jpgHot-spots on Io (at night) - edited72 visiteCaption NASA originale:"The left-hand frame shows the best view that Galileo has yet provided of Io's nighttime temperatures. For reference, the right hand frame, based on Galileo camera images, shows the same hemisphere of Io in visible light. The thin bright crescent indicates the only observable portion illuminated by sunlight during the temperature measurements. Several volcanoes are identified on both images: "L-K" is Lei-Kung Fluctus, "L" is Loki, "Pi" is Pillan, "M" is Marduk and "Pe" is Pele".
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Io-lor_0034685519_0x630_sci_1.jpgIo: the "Sulphur World" from New Horizons103 visitenessun commentoMareKromium
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Io-lor_0034785119_0x630_sci_1~0.jpgIo, from New Horizon (Natural Colors; credits: Lunexit)102 visitenessun commentoMareKromium
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Io-lor_0035102969_0x630_sci_1.jpgMoments of Tvashtar (1)99 visitenessun commentoMareKromium
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Io-lor_0035116949_0x630_sci_1.jpgMoments of Tvashtar (2)103 visitenessun commentoMareKromium
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Io-lor_0035222842_0x630_sci_2.jpgMoments of Tvashtar (3)80 visitenessun commentoMareKromium
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Io-sulphur_s role-PIA02547_modest.jpgThe Role of Sulphur in Io's Volcanoes79 visiteCaption NASA originale:"Sulphur gas, consisting of pairs of sulphur atoms (S2) - as detected above Io's volcano Pele by the HST in October 1999 - is ejected from the hot vents of Io's volcanoes (green arrow). Such sulphur gas lands on the cold surface where the sulphur atoms rearrange into molecules of 3 or 4 atoms (S3 and S4) which give the surface a reddish color. In time, the atoms rearrange into their most stable configuration (S8) that forms ordinary pale-yellow sulphur".
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Io_Europa-040207.jpgIo and Europa, from New Horizons104 visiteThis beautiful image of the crescents of volcanic Io and more sedate Europa was snapped by New Horizons' color Multispectral Visual Imaging Camera (MVIC) at 10:34 UT on March 2, 2007, about two days after New Horizons made its closest approach to Jupiter.
The picture was one of a handful of the Jupiter System that New Horizons took primarily for their artistic, rather than scientific value. This particular scene was suggested by space enthusiast Richard Hendricks of Austin, Texas, in response to an Internet request by New Horizons scientists for evocative, artistic imaging opportunities at Jupiter.
This image was taken from a range of 4,6 MKM (about 2,8 MMs) from Io and 3,8 MKM (about 2,4 MMs) from Europa. Although the moons appear close in this view, a gulf of 790.000 Km (490.000 miles) separates them. The night side of Io is illuminated here by light reflected from Jupiter, which is out of the frame to the right. Europa's night side is completely dark, in contrast to Io, because that side of Europa faces away from Jupiter.
Here, Io steals the show with its beautiful display of volcanic activity. Three volcanic plumes are visible. Most conspicuous is the enormous 300-Km(190-mile) -high plume from the Tvashtar volcano at the 11 o'clock position on Io's disk. Two much smaller plumes are barely visible: one from the volcano Prometheus, at the 9 o'clock position on the edge of Io's disk, and one from the volcano Amirani, seen between Prometheus and Tvashtar along Io's Terminator (the line dividing day and night). The plumes appear blue because of the scattering of light by tiny dust particles ejected by the volcanoes, similar to the blue appearance of smoke. In addition, the contrasting red glow of hot lava can be seen at the source of the Tvashtar plume.
The images are centered at 1 North, 60 West on Io, and 0 North and 149 West on Europa.
The color in this image was generated using individual MVIC images at wavelengths of 480, 620 and 850 nanometers. The human eye is sensitive to slightly shorter wavelengths, from 400 to 700 nanometers, and thus would see the scene slightly differently. For instance, while the eye would notice the difference between the yellow and reddish brown colors of Io's surface and the paler color of Europa, the two worlds appear very similar in color to MVIC's longer-wavelength vision.
The night side of Io appears greenish compared to the day side, because methane in Jupiter's atmosphere absorbs 850-nanometer light and makes Jupiter-light green to MVIC's "eyes."
MVIC is a component of the Ralph imaging instrument. MareKromium
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Io_Europa-lor_0035136929_0x630_sci_1.jpgEuropa and Io in conjunction (1)95 visitenessun commentoMareKromium
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Io_Europa-lor_0035136944_0x630_sci_1.jpgEuropa and Io in conjunction (2)109 visitenessun commentoMareKromium
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JUPITER LIGHTNINGS.jpgJupiter's lightninghs93 visitenessun commento
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