| Piú viste - Saturn: the "Ringed Beauty" and His Moons |
The_Rings-PIA10079.jpgSaturnian "Propellers" (context frame)59 visiteThe Cassini spacecraft captures 8 new propeller-like features within Saturn's A-Ring in what may be the propeller "hot zone" of Saturn's Rings.
Propeller features form around small moonlets that are not massive enough to clear out ring material, but are still able to pull smaller ring particles into a shape reminiscent of an airplane propeller. Scientists believe that propellers represent moonlet wakes, which are denser than the surrounding ring material and appear bright in the images.
Propellers were first discovered in Cassini images taken during Saturn orbit insertion in 2004. This new image is from a more extensive study of the full A-Ring and provides evidence that these features are not distributed evenly as previously thought, but are instead grouped in a 3000 Km-wide (about 1860 mile) Propeller Belt.
The largest propeller seen here is noted in the white dashed box, and it indicates the presence of a 150-meter (490-foot) moonlet. The size is inferred from the radial separation of the propeller wings. The propeller is seen in another image and is shown in the upper left box.
The reappearance of the propellers clearly demonstrates their orbital motion.MareKromium
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Dione-PIA09764.jpgThe "spiderweb like" streaks on Dione59 visiteCaption NASA:"Bright, wispy fractures streak across Dione's trailing side. Following the Voyager flybys of the early 80s, scientists considered the possibility that the streaks were bright material extruded by cryovolcanism. A quarter-century later, Cassini's close passes and sharp vision showed these features to be a system of braided canyons with bright walls.
North on Dione is up.
The image was taken in visible light with the Cassini spacecraft wide-angle camera on Sept. 30, 2007. The view was acquired at a distance of approx. 45.000 Km (such as about 28.000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 36°.
Image scale is roughly 3 Km (about 2 miles) per pixel".MareKromium
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Enceladus-PIA09770.jpgThe "fresh" face of Enceladus59 visiteCaption NASA:"The Leading Hemisphere of Enceladus displays a remarkably fresh-looking surface in this recent Cassini view. At this resolution, only a few craters can be made out in this wrinkled region of the geologically active moon's surface.
A far more heavily cratered, and older, terrain region is visible to the North-West.
This view is centered on 15° North Latitude, 109° West Longitude.
North on Enceladus is up.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 30, 2007. The view was acquired at a distance of approx. 108.000 Km (such as about 67.000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 75°.
Image scale is roughly 646 meters (2.119 feet) per pixel".MareKromium
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Sky-N00097768.jpgStar-trail; moon-trail or in-transit UFO?59 visiteCaption NASA:"N00097768.jpg was taken on November 24, 2007 and received on Earth November 25, 2007. The camera was pointing toward JAPETUS that, at the time, was approx. 1.401.647 Km away, and the image was taken using the CL1 and IR1 filters. This image has not been validated or calibrated".MareKromium
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Atlas_Pan-PIA08405.jpgJust like Flying Saucers: Atlas and Pan59 visiteCaption NASA:"These HR images of Pan and Atlas reveal distinctive "flying saucer" shapes created by prominent Equatorial Ridges not seen on the other small moons of Saturn.
From left to right: a view of Atlas' Trailing Hemisphere, with North up, at a spatial scale of about 1 Km (0,6 mile) per pixel; Atlas seen at about 250 meters (820 feet) per pixel from Mid-Southern Latitudes, with the Sub-Saturn Hemisphere at the top and Leading Hemisphere to the left; Pan's Trailing Hemisphere seen at about 3 Km (about 2 miles) per pixel from low Southern Latitudes; an Equatorial view, with Saturn in the background, of Pan's Anti-Saturn Hemisphere at about 1 Km (0.6 mile) per pixel.
On Atlas, the ridge extends 20 to 30° in latitude on either side of the Equator; on Pan, its latitudinal extent is 15 to 20°. Atlas shows more asymmetry than Pan in having a more rounded ridge in the Leading and Sub-Saturn Quadrants.
The heights of the Ridges can be crudely estimated by assuming (ellipsoidal) shapes that lack ridges and vary smoothly cross the Equator. Heights of Atlas' Ridge range from about 3 Km (about 2 miles) at 270° West Long. to 5 Km (approx. 3 miles) at 180 and 0°. Pan's Ridge reaches about 4 Km (about 2,5 miles) at 0° West Long. and is about 1,5 Km (0,9 mile) high over most of the rest of the Equator.
The ridges represent about 27% of Atlas' volume and 10% of Pan's volume.
The images were acquired with the Cassini Spacecraft narrow-angle camera between 2005 and 2007. Pan is about 33 Km (apprx. 20,5 miles) across at its Equator and about 21 Km (approx. 13 miles) across at its Poles; Atlas is 39 Km (such as about 24 miles) across at its Equator and 18 Km (approx. 11 miles) across at its Poles".MareKromium
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Dione-PIA09861.jpgDione59 visiteCaption NASA:"This southerly view of Dione shows enormous canyons extending from Mid-Latitudes on the Trailing Hemisphere, at right, to the moon's South Polar Region.
This view looks toward the Saturn-facing side of Dione (about 1126 Km, or 700 miles across) and is centered on 22° South Latitude, 359° West Longitude. North on Dione is up; the moon's south pole is seen at bottom.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 8, 2008. The view was obtained at a distance of approx. 211.000 Km (such as about 131.000 miles) from Dione and at a Sun-Dione-Spacecraft, or phase, angle of 20°.
Image scale is roughly 1 Km (0,6 mile) per pixel".MareKromium
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Enceladus-PIA10356.jpgWhat's in "Enceladus Plume"?59 visiteCaption NASA:"The lower panel is a Mass Spectrum that shows the chemical constituents sampled in Enceladus' plume by Cassini's Ion and Neutral Mass Spectrometer during its fly-through of the plume on Mar. 12, 2008.
Shown are the amounts, in atomic mass per elementary charge (Daltons [Da]), of Water Vapor, Methane, Carbon Monoxide, Carbon Dioxide, simple organics and complex organics identified in the plume".MareKromium
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Sun-N00107152.jpgSunshine through the Rings... (natural colors; credits: Lunexit)59 visiteCaption NASA:"Caption NASA:"N00107152.jpg was taken on April 10, 2008 and received on Earth on April 11, 2008. The camera was pointing toward SATURN, F-RING that, at the time, was approx. 611.114 Km away, and the image was taken using the CL1 and CL2 filters. This image has not been validated or calibrated".MareKromium
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Saturn-PIA10358.jpgSaturn's Infrared Temperature Snapshot (Labeled)59 visiteCaption NASA:"Scientists have discovered a wave pattern, or oscillation, in Saturn's atmosphere only visible from Earth every 15 years. The pattern ripples back and forth like a wave within Saturn's upper atmosphere. In this region, temperatures switch from one altitude to the next in a candy cane-like, striped, hot-cold pattern.
The temperature "snapshot" shown in these two images captures two different phases of this wave oscillation: the temperature at Saturn's Equator switches from hot to cold, and temperatures on either side of the Equator switch from cold to hot every Saturn half-year.
The image on the left was taken in 1997 and shows the temperature at the equator is colder than the temperature at 13° South Latitude. Conversely, the image on the right taken in 2006 shows the temperature at the Equator is warmer.
These images were taken with NASA's Infrared Telescope Facility in Mauna Kea, Hawaii".MareKromium
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Enceladus-PIA10403.jpgIcy Oasis (MULTISPECTRUM-2; credits: Lunexit)59 visiteCaption NASA:"With its excess warmth, water ice jets and huge vapor plume laced with simple organic materials, Enceladus is an important part of the quest to understand environments compatible with the chemistry of life as we know it. The Sulci, or "Tiger Stripe" fractures, in the South Polar Region are visible at bottom -- the view here is parallel to the direction of the Sulci.
The view looks toward the anti-Saturn Hemisphere on the moon's Trailing Side. North on Enceladus is towards the top of the image.
This view is a composite of individual frames obtained using filters sensitive to ultraviolet (centered at 338 nanometers), green (centered at 568 nanometers) and infrared light (centered at 1002 nanometers).
The broad range of wavelengths exaggerates subtle color variations across the moon's surface.
The images were acquired with the Cassini spacecraft narrow-angle camera on May 11, 2008.
The view was obtained at a distance of approx. 739.000 Km (such as about 459.000 miles) from Enceladus and at Phase Angle of 36°.
Image scale is roughly 4 Km (about 2,5 miles) per pixel".MareKromium
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Janus-PIA10407.jpgJanus59 visiteCaption NASA:"Craters cover the rugged surface of Saturn's moon Janus. The view is from 42° above the moon's Equator. North on Janus (179 Km, or 111 miles across) is towards the top of the image.
The image was taken with the Cassini Spacecraft narrow-angle camera on May 17, 2008 using a combination of spectral filters sensitive to wavelengths of polarized green light centered at 617 and 568 nanometers. The view was acquired at a distance of approx. 350.000 Km (such as about 217.000 miles) from Janus and at a Sun-Janus-Spacecraft, or phase, angle of 101°.
Image scale is roughly 2 Km (a little more than 1 mile) per pixel".MareKromium
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The_Rings-PIA10426.jpgThe C-Ring and the Upper Atmosphere of Saturn (MULTISPECTRUM-2; credits: Lunexit)59 visiteCaption NASA:"Saturn's C-Ring emerges from behind the Planet's hazy limb. This view looks toward the sunlit side of the Rings from about 15° below the Ring-Plane.
The image was taken in visible light with the Cassini Spacecraft narrow-angle camera on June 17, 2008. The view was obtained at a distance of approx. 937.000 Km (such as about 582.000 miles) from Saturn.
Image scale is roughly 5 Km (a little more than 3 miles) per pixel".MareKromium
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