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| Risultati della ricerca nelle immagini - "Dione" |
0-Saturn and Friends.jpgSaturn and His Moons192 visiteThe dozens of moons orbiting Saturn vary drastically in shape, size, age and origin. Some of these moons have rocky surfaces, while others are porous, icy bodies. Many have craters, ridges and valleys and some show evidence of tectonic activity. Some appear to have formed billions of years ago, while others appear to be pieces of a bigger, fragmented body. The most interesting one is Titan, the biggest of them all. Larger than Earth's Moon, Titan even has its own thick atmosphere - the only natural satellite in the Solar System with such a luxury. During its 4-year mission in this immense region, the Cassini spacecraft will extensively photograph many of these moons and collect data that will increase our understanding of their composition.
To date, 34 moons have been officially named. In alphabetic order, they are: Albiorix, Atlas, Calypso, Dione , Enceladus, Epimetheus, Erriapo, Helene, Hyperion, Iapetus, Ijiraq, Janus, Kiviuq, Methone, Mimas, Mundilfari, Narvi, Paaliaq, Pallene, Pan, Pandora, Phoebe, Polydeuces, Prometheus, Rhea, Siarnaq, Skadi, Suttung, Tarvos, Telesto, Tethys, Thrym, Titan and Ymir.
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A - Saturn-a.jpgSaturn, Tethys and Dione in almost true colors185 visiteSaturn Data and Statistics
Mass (kg) = 5.688e+26
Mass (Earth = 1) = 9,5181e+01
Equatorial radius = 60.268 Km
Equatorial radius (Earth = 1) = 9,4494e+00
Mean density (gm/cm^3) = 0,69
Mean distance from the Sun = 1.429.400.000 Km
Mean distance from the Sun (Earth = 1) = 9,5388
Rotational period (hours) = 10,233
Orbital period (years) = 29,458
Mean orbital velocity = 9,67 Km per second
Tilt of axis = 25,33°
Orbital inclination = 2,488°
Equatorial surface gravity (m/sec^2) = 9,05
Equatorial escape velocity = 35,49 Km per second
Magnitude (Vo) = 0,67
Mean cloud temperature = - 125°C
Atmospheric pressure (bars) = 1,4
Atmospheric composition: Hydrogen 97% and Helium 3%
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Aeneas Crater on Dione.jpgAeneas Crater on Dione175 visitenessun commento
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Dione & Rhea-PIA08261.jpgNight-lights, in the Saturnshine...55 visiteCaption NASA originale:"Soft light from Saturn lifts the veil of night from the moons Dione (lower left) and Rhea (upper right).
A scant crescent on each satellite marks the limit of the Sun's direct reach. The remaining light is reflected onto the moons by the Ringed Planet (Saturn-shine).
This view was acquired using an image compression scheme that results in minor artifacts being present - on Rhea in particular.
Rhea (approx. 1.528 Km, or 949 miles across - pictured above) is somewhat bland in appearance at this image scale, although Dione's spectacular fractures stand out marvelously. Dione is approx. 1.126 Km (about 700 miles) across.
North, on both moons, is rotated 45° to the right.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 11, 2006 at a distance of approx. 2,6 MKM (about 1,6 MMs) from Dione and 2.8 MKM (1,7 MMs) from Rhea. Image scale is about 15 Km (approx. 10 miles) per pixel on Dione and about 17 Km (approx. 11 miles) on Rhea".
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Dione from 6.200.000 Km.jpgDione from 6.200.000 Km55 visitenessun commento
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Dione from Voyager 1.jpgDione from Voyager 1105 visiteUna splendida immagine in "colori naturali" ma con i contrasti leggermente amplificati (amplificati---->enhanced), in maniera tale da favorire la visione dei piccoli dettagli della superficie.
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Dione from appx. 1.400.000.jpgDione from Cassini-Huygens - app.x 1.400.000 Km away58 visitenessun commento
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Dione in 3D.gifDione in 3D54 visitenessun commento
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Dione&Co.-PIA07628.jpgDione, Tethys and Pandora52 visiteOriginal caption:"This excellent grouping of 3 moons - Dione, Tethys and Pandora - near the Rings, provides a sampling of the diversity of worlds that exists in Saturn's Realm. A 330-Km-wide (about 205 miles) impact basin can be seen near the bottom right on Dione (at left). Ithaca Chasma and the Region imaged during the Cassini spacecraft¿s Sept. 24, 2005, flyby can be seen on Tethys (middle). Little Pandora makes a good showing here as well, displaying a hint of surface detail. Tethys is on the far side of the Rings in this view; Dione and Pandora are much nearer to the Cassini spacecraft.
Rememeber that Dione is approx. 1.126 Km (about 700 miles) across. Tethys is approx. 1.071 Km (about 665 miles) across and Pandora is 84 Km (roughly 52 miles) across.
This image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on Sept. 22, 2005, at a distance of approx. 1,2 MKM (about 800.000 miles) from Saturn. The image scale is about 5 Km (approx. 3 miles) per pixel on Dione and Pandora and 9 kilometers (6 miles) per pixel on Tethys".
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Dione&Co.-PIA07679.jpgProportions, dimensions, perspectives and distances...52 visiteOriginal caption:" Two of Saturn's battered, icy companions hover here, above the Ring-Plane.
To get a sense of the three-dimensional nature of the scene, note that the wide band of visible Rings is in between the two moons in this view from the Cassini spacecraft.
Mimas (397 Km, or 247 miles across, at left) is outside the far side of the Rings while Dione (1.126 Km, or 700 miles across) is outside the Rings and closer to Cassini.
The view is from just beneath the Ring-Plane and the image was taken in visible light, with the Cassini spacecraft narrow-angle camera on Dec. 18, 2005, at a distance of approx. 2,2 MKM (roughly 1,4 MMs) from Dione and 2,7 MKM (about 1,7 MMs) from Mimas. The image scale is 13 Km (about 8 miles) per pixel on Dione and 16 Km (about 10 miles) per pixel on Mimas".
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Dione&Janus-PIA08158.jpgSaturn, Dione and Janus52 visiteCaption originale:"The Cassini spacecraft looks toward the Saturnian horizon as Dione and Janus glide past.
A few craters are visible on Dione, while Janus is slightly blurred due to its motion during the exposure. The Rings appear essentially edge-on in this view, as the Cassini spacecraft continues its recent activities close to the Ring-Plane.
The image was taken with the Cassini spacecraft narrow-angle camera on March 10, 2006, using a filter sensitive to wavelengths of infrared light centered at 750 nnmts. The image was acquired at a distance of approx. 2,9 MKM (about 1,8 MMs) from Saturn.
The image scale is approx. 17 Km (roughly 11 miles) per pixel".
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Dione&Tethys-PIA06629.jpgDione and Tethys54 visiteCaption NASA originale:"Cassini offers this lovely comparison between two of Saturn's satellites, Dione and Tethys, which are similar in size but have very different surfaces.
Extensive systems of bright fractures carve the surface of Dione. The double-pronged feature Carthage Linea points toward the crater Turnus at the nine o'clock position near the terminator and Palatine Linea runs toward the moon's bottom limb near the five o'clock position.
In contrast, the surface of Tethys appears brighter and more heavily cratered. The large crater Penelope is near the eastern limb. The huge rift zone Ithaca Chasma, which is 3 to 5 Km deep and extends for about 2.000 Km from north to south across Tethys, is hidden in shadow just beyond the terminator. For comparison, the Grand Canyon in Arizona is about 1,5 Km deep and about 450 Km long.
The image was taken in visible light from a distance of approx. 1,5 MKM from Tethys and 1,6 MKM from Dione. The image scale is 9 Km/pixel on Tethys and 10 Km/pixel on Dione".
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