| Piú votate - Saturn: the "Ringed Beauty" and His Moons |
TheRings-PIA07522.jpgFour versions of the "F-Ring"55 visiteCaption NASA originale:"This montage of 4 images of Saturn's knotted F-Ring shows different locations around the Ring itself. Even though all the images were taken within a few hours of each other, there is remarkable variation in the structure of the F-Ring at these four locations.
For example, the number of ring strands differs from image to image and in some images, kinks are clearly visible in the F-Ring, while other regions appear more smooth.
Astronomers believe that the structure of Saturn's F-Ring is governed by its shepherding moons, Prometheus and Pandora. The F-Ring's appearance is expected to vary depending on how recently a ring section has encountered each moon and how close the moon came to the ring".
Nota: nel primo quadro (in alto a Sx) c'è qualcosa, posto proprio al di sopra del 'nodo' centrale visibile sull'intreccio più luminoso dell'Anello F, che sembra un 'filamento' o, comunque, un oggetto estraneo all'Anello F stesso, ma reale (NON crediamo che sia un photo-artifact). Cos'è?
(12 voti)
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Dione-PIA06155-1.jpgDione and Saturn in natural colors78 visiteCaption NASA originale:"Cassini captured Dione against the globe of Saturn as it approached the icy moon for its close rendezvous on Dec. 14, 2004. This natural color view shows the moon has strong variations in brightness across its surface, but a remarkable lack of color, compared to the warm hues of Saturn's atmosphere. Several oval-shaped storms are present in the planet's atmosphere, along with ripples and waves in the cloud bands.
The images used to create this view were obtained with the Cassini spacecraft wide-angle camera at a distance of approximately 603.000 Km from Dione through a filter sensitive to wavelengths of ultraviolet light centered at 338 nanometers. The Sun-Dione-spacecraft, or phase, angle is 34°. The image scale is about 32 Km per pixel".
(12 voti)
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UnusualObject-N00122114-4.jpgUnusually-looking "Object" in the Space of Saturn (edm n. 2, by Lorenzo Leone)121 visitenessun commentoMareKromium
(11 voti)
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UnusualObject-N00122114-2.jpgUnusually-looking "Object" in the Space of Saturn and possible Gravity Waves (sequential frames; credits: Dr M. Faccin)116 visiteE allora? Che cosa stiamo guardando?!?...E comunque, qualunque cosa sia, una morale possiamo trarla: quando SI SA che cosa cercare, COME cercarla e quando si è anche abbastanza bravi ed attenti nel mettere gli occhi nei frames...alla fine SI TROVA SEMPRE qualcosa!
O no?!?MareKromium
(11 voti)
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Saturn-N00063521-04.jpgSaturnian "Shooting Star" and a Shooting Star from Earth179 visiteIl raffronto fra queste immagini ci sembra una prova sufficiente per poter rivendicare, come Lunar Explorer Italia - e diremmo definitivamente - la paternità di questa piccola (ma, secondo noi, splendida e significativa) scoperta: la prima Stella Cadente colta nello spazio di un mondo diverso dalla Terra!
Peccato che la NASA non abbia niente da dire...
(11 voti)
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Hyperion-N00040356.jpgHyperion (19)54 visiteConto alla rovescia per il passaggio ravvicinatissimo di Cassini accanto ad Hyperion: ora siamo a circa 9000 Km di distanza dalla sua superficie...
(11 voti)
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Saturn-PIA03559.jpgSaturn's clouds in 3D55 visiteSaturn's clouds and hazes at three different levels in the atmosphere are depicted in the image on the right, as observed by the visual infrared mapping spectrometer on the Cassini spacecraft.
In the image, red represents the deepest clouds yet found on Saturn. They are at an altitude where pressure is nearly double Earth's sea-level air pressure. The spectrometer saw these clouds using a 5.1 micron wavelength. Brightness levels in the original image were inverted to show cloud as bright features. Green is an image taken simultaneously at 1.6 micron wavelength, showing upper-level clouds near and above the altitude where atmospheric pressure equals Earth's sea-level air pressure, a pressure expressed as 1 bar. Blue is an image taken at 2.05 micron, a wavelength which is limited to showing only higher cloud level due to absorption of light by the hydrogen gas comprising the bulk of Saturn's atmosphere. Blue indicated clouds of an altitude where atmospheric pressure is only about 70 percent of Earth's sea-level air pressure. Thus, the aqua-colored feature over the equator is high-altitude haze residing 10 kilometers (6 miles) altitude above the typical zonal features seen in reflected sunlight over the planet (green).
The image on the left shows only the upperatmosphere above the 1-bar level, and is the view seen in reflected sunlight as observed by cameras not capable of seeing the thermal radiation of Saturn. Red in this image was taken at 2.79 micron, a wavelength that absorbs ammonia. The greenish appearance of the south pole indicates that ammonia gas is enhanced there.
As opposed to the uniform bands of hazes and clouds seen over the planet at pressures near and less than 1 bar, clouds at the 2-bar level (red, in right-hand image) are distinct, and come in a variety of shapes and sizes.
(11 voti)
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Saturn-PIA03557.jpgSaturn's pressure66 visiteOriginal NASA caption:"This new view on the right side shows clouds at an altitude where pressure is nearly 2 bars. (nota---->1 bar rappresenta l'unità di misura della pressione atmosferica terrestre esistente al livello del mare). These clouds are about 30 Km underneath the clouds usually observed on Saturn. This is distinctly different from the typical view of Saturn in reflected sunlight, shown on the left.
The left view is characterized by broad expanses of clouds near the 1-bar level, such as the white cloud seen circling the Equator, with little hint of the discrete cloud complexes lying underneath (...)".
(11 voti)
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Mimas-PIA07534.jpgRound? Not really...57 visiteCaption NASA originale:"Saturn's moon Mimas, whose low density suggests that it is primarily composed of ice, has a flattened or oblate shape reminiscent of Saturn's. The moon's equatorial dimension is nearly 10% larger than the polar one due to the satellite's rapid rotation. This view shows principally the leading hemisphere on Mimas. Mimas' largest crater, Herschel (130 Km, or 80 miles wide), is centered roughly on the equator and can be seen here. North on Mimas is toward upper left.
The moon's oblateness is exaggerated by Cassini's viewing angle here -- the Sun-Mimas-spacecraft, or phase, angle was only 5° leaving a sliver of the moon's disk in shadow on the northwest limb.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 20, 2005, at a distance of approx. 916.000 Km (about 569.000 miles) from Mimas. Resolution in the original image was 5 Km (about 3 miles) per pixel".
(11 voti)
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The Rings-2-PIA07872.jpgThe "Rings": the most spectacular view ever seen!56 visiteSpecially designed Cassini orbits place Earth and Cassini on opposite sides of Saturn's rings, a geometry known as "occultation". Cassini conducted the 1st radio occultation observation of Saturn's Rings on May 3, 2005.
Three simultaneous radio signals of 0,94; 3,6, and 13 cm wavelengths (Ka-, X-, and S-bands) were sent from Cassini through the rings to Earth. The observed change of each signal as Cassini moved behind the Rings provided a profile of the distribution of ring material as a function of distance from Saturn, or an optical depth profile.
This simulated image was constructed from the measured optical depth profiles. It depicts the observed ring structure at about 10 Km in resolution. Color is used to represent information about ring particle sizes in different regions based on the measured effects of the 3 radio signals. Shades of purple, primarily over most of the inner ring (ring B) and the inner portion of the next ring (ring A), indicate regions where there is a lack of particles less than 5 centimeters (about 2 inches) in diameter. Green and blue shades indicate regions where there are particles of sizes smaller than 5 centimeters (2 inches) and 1 centimeter (less than one third of an inch), respectively, primarily in outer ring A and within most of ring C. From other evidence in the radio observations, all ring regions appear to be populated by a broad range of particle size distribution that extends to boulder sizes (several to many meters or yards across).
(11 voti)
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Saturn.jpgSaturn in real colors54 visitenessun commento
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Saturn-W00003808.jpgSaturn and Dione75 visitenessun commento
(11 voti)
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