Jupiter: the "King" and His Moons
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Jupiter_sMap00-PIA07782-1.jpgSuper-detailed Jupiter's Map (1)67 visiteThis map is part of a group release of cylindrical and polar stereographic projections of Jupiter.
This color map of Jupiter were constructed from images taken by the narrow-angle camera onboard NASA's Cassini spacecraft on Dec. 11 and 12, 2000, as the spacecraft neared Jupiter during its flyby of the giant planet. Cassini was on its way to Saturn. They are the most detailed global color maps of Jupiter ever produced. The smallest visible features are about 120 Km (approx. 75 miles) across.
The maps are composed of 36 images: a pair of images covering Jupiter's Northern and Southern Hemispheres was acquired in two colors every hour for nine hours as Jupiter rotated beneath the spacecraft. Although the raw images are in just two colors, 750 nanometers (near-infrared) and 451 nanometers (blue), the map's colors are close to those the human eye would see when gazing at Jupiter.
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Jupiter_sMap00-PIA07782-2.jpgSuper-detailed Jupiter's Map (2)69 visiteThe map shows a variety of colorful cloud features, including parallel reddish-brown and white bands, the Great Red Spot - frame 1), multi-lobed chaotic regions, white ovals and many small vortices. Many clouds appear in streaks and waves due to continual stretching and folding by Jupiter's winds and turbulence. The bluish-gray features along the north edge of the central bright band are equatorial "hot spots" meteorological systems such as the one entered by NASA's Galileo probe. Small bright spots within the orange band north of the Equator are lightning-bearing thunderstorms. The Polar Regions are less clearly visible because Cassini viewed them at an angle and through thicker atmospheric haze.
Pixels in the rectangular map cover equal increments of planetocentric latitude (which is measured relative to the center of the Planet) and longitude, extending to 180 of latitude and 360 of longitude.
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Jupiter_s_Aurorae.jpgJovian Aurorae65 visiteNASA's HST has recently taken images of Jupiter in support of the New Horizons Mission. The images were taken with Hubble's Wide Field Planetary Camera 2 and the Advanced Camera for Surveys. Hubble will continue to photograph Jupiter, as well as its volcanically active moon, Io, over the next month as the New Horizons spacecraft flies past Jupiter. New Horizons is en route to Pluto, and made its closest approach to Jupiter on February 28, 2007. Through combined remote imaging by Hubble and in situ measurements by New Horizons, the two missions will enhance each other scientifically, allowing scientists to learn more about the Jovian atmosphere, the Aurorae, and the charged-particle environment of Jupiter and its interaction with the Solar Wind.
For this photo, the combined ultraviolet- and visible-light images of Jupiter were taken with Hubble from February 17-21. The image segments in the boxes, obtained using the Advanced Camera for Surveys's ultraviolet camera, show auroral emissions that are always present in Jupiter's polar regions. The equatorial regions of Jupiter were imaged in blue light by the Wide Field Planetary Camera 2. Cloud features in Jupiter's main atmosphere are revealed. In the ultraviolet views, the atmosphere looks more hazy because sunlight is reflected from higher in the atmosphere.MareKromium
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Jupiter_sofiawesley.jpgJupiter from the Stratosphere158 visiteDalla Rubruica "NASA - Picture of the Day", del giorno 3 Giugno 2010:"SOFIA, the Stratospheric Observatory for InfraRed Astronomy, captured its "first light" images on May 26, from an altitude of 35.000 feet.
While flying above most of planet Earth's InfraRed-absorbing water vapor, SOFIA's premier IR views of the cosmos included this remarkable false-color image (right panel) of Jupiter.
For comparison, on the left is a recent, ground-based visible light image. Both show our Solar System's ruling gas giant without its dark Southern Equatorial Belt (normally seen in the upper Hemisphere in this orientation). That familiar feature faded from view early in May. But the bright white stripe in SOFIA's image is a region of Jupiter's clouds transparent to IR Light, offering a glimpse below the cloud tops".MareKromium
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Jupitercrescent_cassini_big.jpgJupiter from Cassini80 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~0.jpgThe "true" colors of Jupiter (an interpretation)155 visiteJupiter has several narrow belts of distinct colors as well as reddish oval shaped stable cyclonic weather zones such as the 'Great Red Spot'. The overall albedo of the planet is 0,52. The colors shown in the strips are of the wider alternating belts and zones extending from either side of the often white Equatorial Zone.
This is a Voyager 1 image assembled from raw data and color balanced to approximate the colors and contrast of the Planet.
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Jupiter~1.jpgThe "Eyes" of Jupiter: a change of colors could mean a climate change?64 visiteJupiter's Great Red Spot is a swirling storm seen for over 300 years, since the beginning of telescopic observations. But in February 2006, planetary imager Christopher Go noticed it had been joined by Red Spot Jr - formed as smaller whitish oval-shaped storms merged and then developed the remarkable reddish hue. This sharp HST image showing the two salmon-colored Jovian storms was recorded in April 2006. About half the size of the original Red Spot, Red Spot Jr. is similar in diameter to planet Earth. Seen here below and left of the ancient storm system, it trails the Great Red Spot by about an hour as the planet rotates from left to right. While astronomers still don't exactly understand why Jupiter's red spots are red, they do think the appearance of Red Spot Jr. provides evidence for climate change on the Solar System's ruling Gas Giant.
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Metis-Galileo.jpgMetis (Natural Colors; credits: Ted Stryk)68 visiteMetis, o Metide, il pi interno fra i Satelliti Naturali di Giove. Appartiene al cosiddetto gruppo di Amaltea, che si compone dei piccoli satelliti interni del Pianeta. Il suo nome storico Giove XVI.
La scoperta di Metis risale al 1979, quando fu individuato grazie alle immagini inviate a Terra dalla sonda spaziale statunitense Voyager 1 e gli venne attribuito il nome provvisorio S/1979 J3; nel 1983 l'Unione Astronomica Internazionale lo battezz ufficialmente con il nome della titanide Metide, prima moglie di Zeus e madre di Atena secondo la Mitologia Greca.
Il colorito giallo-rossastro che stato attribuito a questo Corpo Celeste da Ted Stryk potrebbe trovare una giustificazione negli accumuli (depositi superficiali) di Zolfo che Metis - periodicamente - "raccoglie" dallo Spazio durante i suoi passaggi ravvicinati ad Io.MareKromium
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Orbital_Resonance.gifThe "Orbital Resonance" (GIF-Movie; credits: http://fisicaondemusica.unimore.it.)75 visitePremessa: il moto di un Corpo Celeste in orbita attorno ad un altro Corpo Celeste di massa molto maggiore (ex.: un pianeta attorno ad una stella, o un satellite attorno ad un pianeta) un "Moto Periodico Semplice" ("Moto Circolare Uniforme").
Ora, pu accadere che due (o pi) pianeti si trovino ad orbitare attorno alla medesima stella (o che due - o pi - satelliti si trovino ad orbitare attorno al medesimo "Parent Planet") con tempi di rivoluzione (---> i "Periodi del loro Moto") i quali stanno tra loro in rapporto di due piccoli interi (come 2:1, 2:3, ecc. - si legge "due a uno", "due a tre" etc.).
In questo caso, anche la loro reciproca attrazione gravitazionale verr ad assumere un carattere di periodicit: essa cio aumenter quando i due pianeti si avvicinano, e diminuir quando essi si allontanano.
Se queste variazioni della forza attrattiva gravitazionale sentita da ciascun pianeta saranno significative per la sua orbita, questa potr modificarsi. Ed a tal punto sar possibile identficare due scenari:
1) il moto dei pianeti diviene instabile: le orbite cambiano lentamente finch i due corpi non si influenzano pi sensibilmente. (nota: nel caso di un Corpo Celeste Maggiore ed uno minore, questo effetto si risolver nello "scacciare" il corpo minore da certe zone dello spazio, "liberando" la strada al Corpo Maggiore)
2) i due pianeti non si avvicinano mai abbastanza da influenzarsi violentemente, e quindi entrano in risonanza stabile.
(nota: le loro orbite, in questo caso, subiranno delle modificazioni le quali verranno poi compensate - rectius: annullate - dal verificarsi di modificazioni contrarie nell'arco di ogni rivoluzione)
per maggiori info: http://fisicaondemusica.unimore.it.MareKromium
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PSP_002162_9030_RED_browse.jpgJupiter from Mars71 visiteCaption NASA:"The HiRISE camera is the most powerful telescope to have left Earth orbit. As such, it is capable of some interesting astronomical observations.
This image of Jupiter and its major satellites was acquired to calibrate the pointing and color response of the camera. An oversight in planning this unusual observation put the focus mechanism in the wrong location, blurring the image. This does not detract from the calibration objectives, but makes the raw image less esthetic.
To compensate, the image has been "sharpened" on the ground by Dennis Gallagher, the HiRISE chief optical designer. With this sharpening, and because Mars is closer to Jupiter than Earth is, this image has comparable resolution as the HST's pictures of Jupiter.
The colors are not what is seen by the human eye because HiRISE is able to detect light with a slightly longer wavelength than we can (that is, the infrared)".MareKromium
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The Galileans~0.jpgThe "Galileans"67 visiteIo, the large volcanic satellite of Jupiter, was first shown to the World in images transmitted from the Voyager 1 Spacecraft.
Unfortunately their cameras had no red filters and color pictures often had to be extrapolated substituting orange for red and violet for blue.
In the case of Io, this led to a garish 'pizza' appearance with many reproductions of the released images further wandering toward the red until Io looked like tomato soup!
Io is very bright, and largely a pale yellow with gray green to orange regions. Galileo has greatly refined the color information from Io. The albedo of Io (il primo a Sx) is a bright 0,6, while Europa (the brightest) is 0,64. Ganymede's albedo is just 0,42 and then - last - the dark Callisto is only 0,2.
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Thebe-Amalthea-Metis-PIA02531.jpgThebe, Amalthea and Metis67 visiteUna curiosit: difficile non notare la notevole somiglianza fra Thebe (il primo "macigno" da Sx) e la Luna Marziana Phobos.
E qual' il "punto di contatto" fra questi due corpi celesti?
Ma si tratta, naturalmente, del grande cratere che, nel caso di Thebe, notiamo sulla Sx del piccolo Satellite. Un grande cratere che ci ricorda molto da vicino lo "Stickney Crater" di Phobos.
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