Saturn: the "Ringed Beauty" and His Moons
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Saturn-North_Pole-Vortex-Cassini-EB-MF-LXTT-IPF.gifPeering into the Storm (a GIF-Movie by Elisabetta Bonora and Marco Faccin/Lunar Explorer Italia/Italian Planetary Foundation)75 visite...Splendido e Affascinante...MareKromium
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Saturn-North_Pole-Vortex-Cassini_1024-PCF-LXTT-IPF.jpgPeering into the Storm (Absolute Natural Colors - Credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)89 visiteThe NASA - Cassini Spacecraft has been traveling the Saturnian System in a set of inclined, or "tilted", orbits that are giving to the mission scientists a vertigo-inducing view of Saturn's Polar Regions. This perspective has yielded images of roiling Storm Clouds and a swirling Vortex at the center of Saturn's famed North Polar Hexagon. This phenomenon mimic what Cassini found at Saturn's South Pole a few years ago. The Spacecraft has also seen several Storms circling Saturn's North Pole in the past, but only in InfraRed Wavelengths, since the North Pole was in complete darkness. But now, with the change of the Saturnian Season, the Sun has finally begun to creep over the Gas-Giant Planet's North Pole, which has therefore become visible even in the Wavelenghts of Visible Light. This particular image was taken on November, 27, 2012, with Cassini's Narrow-Angle Camera. The Camera, at the time the picture was obtained, was pointing toward Saturn from approximately 224.618 miles (such as about 361.488 kilometers) away.
This picture (which is an Original NASA - Cassini Spacecraft b/w frame identified by the n. IMG004677-br500) has been additionally processed and then colorized, according to an informed speculation carried out by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Cassini Spacecraft and then looked outside, towards the North Pole of Saturn), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present in the Atmosphere of Saturn, each having a different Albedo (---> Reflectivity) and Chemical Composition. MareKromium
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Saturn-PIA01941.jpgInfrared Saturn63 visiteIn this image, Saturn's fascinating meteorology manifests itself in a "string of pearls" formation, spanning over 60.000 Km (about 37.000 miles). Seen in new images acquired by Cassini's VIMS (Visual and Infrared Mapping Spectrometer) and lit from below by Saturn's internal thermal glow, the bright "pearls" are actually clearings in Saturn's deep cloud system. More than two dozen occur at 40° North Latitude. Each clearing follows another at a regular spacing of some 3,5° in Longitude.
This is the first time such a regular and extensive train of cloud-clearings has been observed. The regularity indicates that they may be a manifestation of a large planetary wave. Scientists plan to take more observations of this phenomenon over the next few years to try to understand Saturn's deep circulation systems and meteorology. This image was taken on April 27, 2006.
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Saturn-PIA03557.jpgSaturn's pressure65 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 (...)".
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Saturn-PIA03559.jpgSaturn's clouds in 3D54 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.
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Saturn-PIA06164-br500.jpgSaturn, Titan and Mimas in real colors53 visiteCaption NASA originale:"From its station nearly 1,2 BKMs (or 746 MMs) from Earth, the stalwart Cassini spacecraft sends holiday greetings to Earth with this lovely color portrait of Saturn and two of its moons. This color portrait serves as reminder of the Saturnian places we have already seen and the promise of future discovery at Titan when the European Space Agency's Huygens probe arrives at Titan on Jan. 14, 2005. A grayish, oval-shaped storm is visible in Saturn's southern hemisphere and is easily 475 Km across - the size of some hurricanes on Earth. Titan is visible near lower right with its thick, orange-colored atmosphere, and faint Mimas (398 Km across) appears just right of the rings' outer edge. Images taken in the red, green and blue filters with the Cassini spacecraft wide angle camera on Dec. 14, 2004, were combined to create this color view at a distance of approximately 719.000 Km from Saturn. The image scale is 43 Km (or 27 miles) per pixel".
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Saturn-PIA06177.jpgSaturn's Northern Hemisphere in natural colors53 visiteCaption NASA originale:"Saturn's Northern Hemisphere is presently a serene blue, more befitting of Uranus or Neptune, as seen in this natural color image from Cassini.
Light rays here travel a much longer path through the relatively cloud-free upper atmosphere. Along this path, shorter wavelength blue light rays are scattered effectively by gases in the atmosphere and it is this scattered light that gives the region its blue appearance. Why the upper atmosphere in the northern hemisphere is so cloud-free is not known, but may be related to colder temperatures brought on by the ring shadows cast there.
Shadows cast by the rings surround the pole, looking almost like dark atmospheric bands. The ring shadows at higher latitudes correspond to locations on the ringplane that are farther from the planet - i.e.: the northernmost ring shadow in this view is made by the outer edge of the A-Ring.
Spots of bright clouds also are visible throughout the region. This view is similar to an infrared image obtained by Cassini at nearly the same time".
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Saturn-PIA06194.jpgAre these "anomalies" the clock-tracks of a New Moon?53 visiteUna piccola premessa: le irregolarità fisiche del margine esterno dell'Anello A, situate in prossimità di quella zona conosciuta come Divisione Keeler (larga circa 42 Km), sono ritenute dalla NASA una evidenza indiretta (o prova circostanziale) dell'esistenza di una nuova 'luna nascosta'. In realtà, queste alterazioni fisiche - le quali altro non sono che il riflesso visibile delle interazioni gravitazionali esercitate da corpi sufficientemente vicini - allorchè i corpi interagenti sono, almeno relativamente, "stabili" (come dobbiamo ragionevolmente supporre che sia nel nostro caso), si caratterizzano per una sostanziale regolarità e ripetitività. Ora nell'immagine di riferimento, come potete vedere Voi stessi, questa 'anomalia gravitazionale' sembra tutt'altro che regolare e ripetitiva. Perchè non provare a pensare, dunque, ad una vera e propria 'interazione complessa' (possibile indice della presenza di più lune) o, magari, a qualcosa di diverso (per esempio ad un - raro - Fenomeno Transitorio)?
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Saturn-PIA06196.jpgGravitational Anomalies and Interferences53 visiteIn fondo, per quanto ne sappiamo, i Fenomeni Transitori non sono una prerogativa unica della superficie dei pianeti e non si manifestano solamente attraverso 'outgassing', 'annebbiamenti' e/o fenomeni luminosi! Anche i fenomeni gravitazionali possono essere transitori, allorchè ci si trovi in un ambiente - per così dire - "affollato" da corpi celesti, quale può essere un'area di confine di uno degli Anelli di Saturno. Comunque eccoVi una parte della Caption NASA originale al riguardo:"Images taken of Saturn's rings by Cassini immediately after it entered orbit around Saturn have turned up circumstantial evidence that an unseen moon may be orbiting dead center in the narrow Keeler Gap in Saturn's outer A-Ring. Several faint discontinuities, or spikes, in the outer gap edge have been found in 2 narrow-angle camera images of the illuminated side of the Rings. These features are similar to the spikes protruding inward from the core of the F-Ring during Prometheus's passages and it is likely that the features are caused by the passages of a yet-unseen moonlet on an eccentric orbit within the Keeler gap".
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Saturn-PIA06436.jpgSaturn's Aurora53 visiteThe Cassini spacecraft has obtained new images of Saturn's auroral emissions, which are similar to Earth's Northern Lights. Images taken on June 21, 2005, with Cassini's UVA Imaging Spectrograph are the first from the mission to capture the entire "oval" of the auroral emissions at Saturn's South Pole.
In the side-by-side, false-color images, blue represents aurora emissions from H gas excited by electron bombardment, while red-orange represents reflected sunlight. The images show that the aurora lights at the Polar Regions respond rapidly to changes in the Solar Wind. Previous images have been taken closer to the Equator, making it difficult to see the Polar Regions. Changes in the emissions inside the Saturn South-Pole aurora are visible by comparing the 2 images, taken about 1 hour apart. The brightest spot in the left aurora fades and a bright spot appears in the middle of the aurora in the second image. Like Earth's aurora, those on Saturn form in an oval at high latitudes around each pole, along with associated spots and streaks. The ultraviolet imaging spectrograph data shows that the Saturn aurora lasts at least one hour, but small changes are visible in that time between the two images.
The same process produces auroras on both planets: variations in the plasma environment release trapped electrons, which stream along the magnetic field lines into the upper atmosphere. There, they collide with atoms and molecules, exciting them to higher energies. The atoms and molecules release this added energy by radiating light at particular characteristic colors and wavelengths. On Earth, this light is mostly from oxygen atoms and nitrogen molecules. On Saturn, it is from emissions of molecular and atomic hydrogen.
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Saturn-PIA06485_modest.jpgSaturn, Janus and Mimas (in natural colors)53 visiteCaption NASA originale:"Looking something like the fibrous bow of a violin, Saturn's colorful rings sweep through this spectacular natural color view while two small moons look on.
From left, the moons visible here are Janus (181 Km across) and Mimas (398 Km across). Cassini's view in this image is from beneath the ring plane; the moons are on the far side of Saturn. Janus leads Mimas as the two moons orbit the planet. Nearly the entire ring system can be seen in this view. The diaphanous C-Ring appears at the upper right, followed by the multi-hued B-Ring. Next, the famous Cassini division (4.800 Km wide) separates the A and B rings. The outer edge of the B-Ring which forms the inner boundary of the Cassini division is maintained by a gravitational resonance with Mimas. Near the outer edge of the A-Ring are the Encke Gap (325 Km wide) and the barely visible Keeler Gap (35 Km wide). The faint, thread-like F-Ring is slightly discernible just beyond the main rings".
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Saturn-PIA06491_modest.jpgSaturn's swirls and ribbons53 visiteCaption NASA originale:"This Cassini image shows mesmerizing detail in the swirls and ribbons of air in Saturn's atmosphere. The view was obtained at a distance of 8.5 million Km from Saturn and is but a taste of what the spacecraft's powerful cameras will show when Cassini draws nearer to the planet. The limb of the planet is visible at lower right.
The image was taken with the Cassini spacecraft narrow angle camera on Sept. 15, 2004, through a filter sensitive to wavelengths of infrared light. The image scale is 101 Km per pixel. The image was magnified by a factor of two and slightly contrast enhanced to improve visibility of features in the atmosphere".
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