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Saturn: the "Ringed Beauty" and His Moons
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Saturn-PIA09012.jpgIncoming Storm55 visiteCaption NASA:"A great vortex, ringed by bright clouds, rolls through the Southern Skies of Saturn in this Cassini spacecraft view.
The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 750 nanometers. The view was obtained with the Cassini spacecraft narrow-angle camera on July 11, 2007 at a distance of approx. 2,8 MKM (such as about 1,8 MMs) from Saturn.
Image scale is roughly 17 Km (about 10 miles) per pixel".MareKromium
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Saturn-PIA09185.jpgThe Saturnian "Hexagon" and Aurora55 visiteThis nighttime view of Saturn's north pole by the visual and infrared mapping spectrometer on NASA's Cassini orbiter reveals a dynamic, active planet at least 75 kilometers (47 miles) below the normal cloud tops seen in visible light. Clearly revealed is the bizarre six-sided hexagon feature present at the north pole.
This image is one of the first clear images of the north polar region ever acquired from a unique polar perspective. In this image, the blue color shows high-altitude emissions from atmospheric molecules excited by charged particles smashing into the atmosphere along Saturn's powerful magnetic field lines, producing the aurora at very high altitudes in Saturn's atmosphere. The red color indicates the amount of 5-micron wavelength radiation, or heat, generated in the depths of the warm interior of Saturn that escapes the planet. Clouds blocking this light are revealed as silhouettes against the background thermal glow of the planet.
This image is among the first to capture the entire hexagonal feature and north polar region in one shot. It is also one of the first polar views using Saturn's thermal glow at 5 microns (seven times the wavelength visible to the human eye) as the light source. This allows polar cloud features to be revealed during the persistent nighttime conditions under way during north polar winter.
The hexagonal feature was originally discovered by NASA's Voyager spacecraft in 1980, but those images and subsequent ground-based telescope images suffered from poor viewing perspectives, which placed the feature and the north pole at the extreme northern limb (edge) in those images.
The strong brightness of the hexagon feature indicates that it is primarily a clearing in the clouds, which extends deep into the atmosphere, at least down to the 3-bar (3-Earth atmospheres pressure) level, about 75 kilometers (47 miles) below the clouds and hazes seen in visible wavelengths. Thick clouds border both sides of the narrow feature, as indicated by the adjacent dark lanes paralleling the bright hexagon. This image and other images acquired over a 12-day period between Oct. 30 and Nov. 11, 2006, show that the feature is nearly stationary, and likely is an unusually strong pole-encircling planetary wave that extends deep into the atmosphere.
This image was acquired by the Cassini visual and infrared mapping spectrometer on Oct. 29, 2006, from an average distance of 905,000 kilometers (562,340 miles) above the clouds.
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Saturn-PIA09186.jpgNight view of the "Hexagon"54 visiteThis nighttime view of Saturn's north pole by the visual and infrared mapping spectrometer onboard NASA's Cassini orbiter clearly shows a bizarre six-sided hexagon feature encircling the entire north pole. This is one of the first clear images taken of the north polar region ever acquired from a unique polar perspective.
In this image, the red color indicates the amount of 5-micron wavelength radiation, or heat, generated in the warm interior of Saturn that escapes the planet. Clouds near 3-bar (about 100 kilometers or 62 miles deeper than seen in visible wavelengths) block the light, revealing them in silhouette against the background thermal glow of Saturn. The bluish color shows sunlight striking the far limb (edge) of the planet, showing that the entire north pole is under the nighttime conditions characteristic of polar winter, as on Earth.
This image is the first to capture the entire feature and north polar region in one shot, and is also the first polar view using Saturn's thermal glow at 5 microns (seven times the wavelength visible to the human eye) as the light source. This allows the pole to be revealed during the persistent nighttime conditions under way during winter. The hexagon feature was originally discovered by NASA's Voyager spacecraft in 1980, but those historic images and subsequent ground-based telescope images suffered from poor viewing perspectives, which placed the feature and the north pole at the extreme northern limb (edge) in those images.
In the new infrared images, the strong brightness of the hexagon feature indicates that it is primarily a clearing in the clouds, which extends deep into the atmosphere, at least some 75 kilometers (47 miles) underneath the typical upper hazes and clouds seen in the daytime imagery by Voyager. Thick clouds border both sides of the narrow feature, as indicated by the adjacent dark lanes paralleling the bright hexagon. This and other images acquired over a 12-day period between Oct. 30 and Nov. 11, 2006, show that the feature is nearly stationary, and likely is an unusually strong pole-encircling planetary wave that extends deep into the atmosphere.
This image was acquired with the Cassini visual and infrared mapping spectrometer on Oct. 30, 2006, from an average distance of 1.3 million kilometers (807,782 miles).
Nota Lunexit: ed ora, quanto ci scommettiamo che, entro (al massimo) 48 ore, il Prof. Hoagland e la Sua Scuola (e, probabilmente, tanti altri Guru della Scienza di Confine) inizieranno a parlare - con estrema saccenza - di "artificialità" dell'Esagono e (perchè no?) della probabile natura artificiale di tutto il Gigante Anellato?
Stay tuned!
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Saturn-PIA09187.gifWatch the "Hexagon" rotate! (GIF-Movie)54 visiteThis nighttime movie of the depths of the North Pole of Saturn taken by the VIMS onboard NASA's Cassini Orbiter reveals a dynamic, active planet lurking underneath the ubiquitous cover of upper-level hazes. The defining feature of Saturn's North Polar Regions -- the six-sided hexagon feature -- is clearly visible in the image.
Here, brightness indicates the amount of 5-micron (seven times the wavelength visible to the human eye) radiation, or heat, generated in the depths of the warm interior of Saturn that escapes the planet. Clouds at a depth equivalent to 3-Earth-atmospheres pressure block the light radiating from below, revealing themselves in dark silhouette against the background thermal glow of the Planet. These deep clouds lie some 75 Km (about 47 miles) underneath the typical ammonia hazes and clouds seen in visual imagery and are likely composed of ammonia-hydrosulfide, although some may be composed of water, as on Earth.
A prominent feature seen in this polar view is a strange hexagon wave feature circumscribing the north pole.
This nighttime movie was acquired over a one-hour period on Nov. 10, 2006, from an average distance of 1.03 million kilometers (621,000 miles) above Saturn's clouds.
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Saturn-PIA09722.jpgSub-Equatorial Saturnian Clouds (natural colors - elab. Lunexit)55 visiteCaption NASA:"A chevron-shaped pattern and bright vortices stand out in the turbulent Saturnian Atmosphere. Such features are hallmarks of the boundary between alternating East-West flowing cloud bands.
This view looks toward an area about 9° South of the Planet's Equator.
The image was taken with the Cassini spacecraft wide-angle camera on July 28, 2007 using a spectral filter sensitive to wavelengths of infrared light centered at 889 nanometers. The view was acquired at a distance of approx. 3,1 MKM (such as about 1,9 MMs) from Saturn.
Image scale is roughly 37 Km (approx. 23 miles) per pixel".MareKromium
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Saturn-PIA09734.jpgTurbulences55 visiteCaption NASA:"The Cassini Spacecraft has a peek beneath the hazes in Saturn's Upper Atmosphere at the swirling vortices that lurk below.
Many vortices can be seen in this image, varying in size from small to large.
The largest one in this image exhibits a collar of bright clouds surrounding the central dark core.
The view is centered on a region about 46° South of the Planet's Equator.
The image was taken with the Cassini spacecraft narrow-angle camera on Aug. 12, 2007 using a spectral filter sensitive to wavelengths of infrared light centered at 750 nanometers. The view was acquired at a distance of approx. 4,1 MKM (such as about 2,5 MMs) from Saturn.
Image scale is roughly 24 Km (about 15 miles) per pixel".MareKromium
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Saturn-PIA09776.jpgJust like the Solar System!56 visiteCaption NASA:"Saturn's icy satellites wheel about the colorful Giant Planet, while the Rings shine dimly in scattered sunlight. The Ringed Planet is, in many ways, a laboratory for investigating the history of our Solar System and how planets form around other stars. There are 4 moons visible in this view. Tethys (1071 Km, or 665 miles across), largest in the scene, is on the far side of the Ring-Plane. Mimas (397 Km, or 247 miles across), is the one on the near side of the Rings, below Tethys. Janus (181 Km, or 113 miles across), is left of the Rings' edge. Pandora (84 Km, or 52 miles across) is a speck below the Rings' edge, between Janus and Mimas. Mimas casts a shadow onto Saturn's bluish Northern Hemisphere.
This view looks toward the unilluminated side of the Rings from about 2° above the Ring-Plane. Images taken using red, green and blue spectral filters were combined to create this natural color view. The view was acquired with the Cassini spacecraft wide-angle camera on Oct. 30, 2007.
The view was taken at a distance of approx. 2,6 MKM (such as about 1,6 MMs) from Saturn.
Image scale is roughly 153 Km (about 95 miles) per pixel on the Planet".MareKromium
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Saturn-PIA09778.jpgMonitoring the Maelstrom62 visiteCaption NASA:"Clouds and vortices churn in this beautiful, close-up view of Saturn. This image is part of a series of important Cassini observations designed to provide information about winds and convection on Saturn.
The view is centered on a Region 44° North of Saturn 's Equator.
The image was taken with the Cassini spacecraft narrow-angle camera on Nov. 7, 2007 using a spectral filter sensitive to wavelengths of infrared light centered at 750 nanometers. The view was acquired at a distance of approx. 2,9 MKM (such as about 1,8 MMs) from Saturn.
Image scale is roughly 17 Km (11 miles) per pixel".MareKromium
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Saturn-PIA09793.jpgThe Northern Hemisphere of Saturn (natural colors; credits: NASA/Space Science Inst.)55 visiteCaption NASA:"Dark ring shadows adorn the Northern Hemisphere of Saturn.
The shadows have loosened their grip on the North compared to when Cassini arrived in 2004, and presently continue to slide farther South.
This view looks toward the unilluminated side of the rings from about 5° above the Ring-Plane. Images taken using red, green and blue spectral filters were combined to create this Natural Color View. The view was acquired with the Cassini spacecraft wide-angle camera on Oct. 22, 2007, at a distance of approx. 1,3 MKM (such as about 839.000 miles) from Saturn.
Image scale is roughly 77 Km (about 48 miles) per pixel".MareKromium
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Saturn-PIA09795.jpgObscure Planet, Bright Moons... (IR)55 visiteCaption NASA:"Just before Rhea slipped behind Saturn, the Cassini Spacecraft captured the moon in its disappearing act.
Along with the partly obscured Rhea are Tethys, at right, and Enceladus, left of Tethys.
At the wavelength in which this image was taken, absorption of Sunlight by Methane gas in Saturn's Atmosphere is strong, causing the Planet to appear darker than at other wavelengths.
This view looks toward the unilluminated side of the Rings from about 4° above the Ring-Plane. The image was taken with the Cassini spacecraft wide-angle camera on Nov. 9, 2007 using a spectral filter sensitive to wavelengths of Infrared Light centered at 890 nanometers. The view was acquired at a distance of approx. 2,8 MKM (about 1,7 MMs) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 44°.
Image scale is roughly162 Km (such as about 101 miles) per pixel".MareKromium
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Saturn-PIA09828.jpgNorthern Latitudes (possible natural colors; credits: Lunexit)54 visiteCaption NASA:"As seasons change on Saturn, and sunlight creeps farther north, the region surrounding the North Pole is steadily coming to light. This scene reveals many features in Saturn's dynamic and beautiful Atmosphere, including a detail largely obscured from the imaging cameras until now: on the Terminator at center right is part of the Polar Hexagon, which was previously observed by Cassini's Visible and Infrared Mapping Spectrometer (VIMS) and Composite Infrared Spectrometer (CIRS).
These instruments used heat radiated from Saturn to observe the Polar Hexagon (rather than reflected sunlight, as is the case in this view). The Hexagon was first imaged by the Voyager spacecraft more than 25 years ago.
The view looks toward the unilluminated side of the Rings from about 38° above the Ring-Plane and is centered on a region 63° north of the Saturnian Equator.
The image has been brightened to show details at high Northern Latitudes, where solar illumination is presently weak.
The image was taken with the Cassini spacecraft wide-angle camera on Jan. 2, 2008 using a combination of spectral filters sensitive to wavelengths of polarized infrared light centered at 752 and 705 nanometers. The view was acquired at a distance of approx. 930.000 Km (about 578.000 miles) from Saturn.
Image scale is roughly 52 Km (approx. 32 miles) per pixel".MareKromium
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Saturn-PIA09854.jpgThe Southern Hemisphere of Saturn (natural colors - credits: NASA/SSI)54 visiteCaption NASA:"Saturn's Southern Hemisphere is glimpsed through the Gossamer Veil of its Rings. Ring shadows adorn the low Northern Latitudes.
This view looks toward the unilluminated side of the Rings from about 22° above the Ring-Plane. Images taken using red, green and blue spectral filters were combined to create this natural color view.
The images were acquired with the Cassini spacecraft wide-angle camera on Dec. 16, 2007 at a distance of approx. 1,5 MKM (about 908.000 miles) from Saturn.
Image scale is roughly 84 Km (approx. 52 miles) per pixel".MareKromium
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