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| Piú votate - Saturn: the "Ringed Beauty" and His Moons |
Saturn-North_Pole-PIA14945-PCF-LXTT-IPF.jpgNorth Polar Spring (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)70 visiteThe North Pole of the Gas-Giant Planet Saturn, now illuminated by the fresh lights of the incoming Spring, is finally revealed in this image taken by the NASA - Cassini Spacecraft on November 27, 2012. As you know, the North Pole of Saturn has been hiding for a long time from the gaze of the Cassini's Imaging Cameras, and that circumstance was due to the fact that it was still Wintertime in (and therefore a deep darkness all over) the Northern Hemisphere of the Ringed Planet when the Spacecraft arrived in the Saturnian System in the AD 2004.
A Hurricane-like Storm circling Saturn's North Pole at about 89° North Latitude is also well visible inside the famous "Hexagon" Feature, which scientists think is a wandering Jet-Stream that whips around the North Pole of Saturn at a relatively constant mean speed of about 220 miles per hour (such as a little more than 354 Km per hour). Such a Jet-Stream it is folded into a six-sided shape because the Hexagon is a Stationary Wave that guides the path of the Gases existing inside the Jet itself. The Hexagon borders occur at about 77° North Latitude and the Feature is wider than two (flat) Earths. Last, but not least, a little section of the Rings of Saturn can also be seen in the upper right corner of the image.
This frame was acquired with the NASA - Cassini Spacecraft Wide-Angle Camera at a distance of approximately 260.000 miles (such as a little more than 418.000 Km) from the top of the Saturnian Clouds and at a Sun-Saturn-Cassini Spacecraft, or Phase, Angle of 96°. Image scale is roughly 18 miles (such as 28,968 Km) per pixel. For another image of the Hexagon and the Hurricane-like Storm that encircles the North Pole of Saturn, please refer to the APOD of December, 29, 2012.
This frame (which is a NASA - CASSINI Spacecraft Original Natural Color frame published on the NASA - Planetary Photojournal and identified by the serial n. PIA 14945) has been additionally processed, magnified, contrast enhanced and then re-colorized, according to an educated guess 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 Satun), 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 in the Upper Atmosphere of Satun, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
(4 voti)
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Rhea-PIA14660-PCF-LXTT-IPF.jpgFarewell to Rhea (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)77 visiteOn its fourth and final targeted Fly-By of Rhea, the NASA - Cassini Spacecraft provided, among others, this stunning view its ancient, tormented and heavily cratered Surface. Billions of years of impacts, in fact, have sculpted Rhea's Surface into the form we see today and, with a diameter of approx. 950 miles (such as about 1528,8 Km), Rhea is the second-largest moon of Saturn.
This view is centered on Terrain located at 33° North Latitude and 358° West Longitude. The image was taken in Visible Light with the NASA - Cassini Spacecraft Narrow-Angle Camera on March 9, 2013, at a distance of approximately 2.348 miles (such as about 3.778,73 Km) from the Surface of Rhea. Just out of curiosity, we, as IPF, have found (as far as this specific picture is concerned) a slight discrepancy between the data regarding the distance of the NASA - Cassini Spacecraft from the Surface of Rhea, as reported in the NASA - Planetary Photojournal (where it has been written that the distance was of approx. 2.280 miles) and in the caption attached to this frame - entitled "Rhea's Shadowy Craters" - and reported in the NASA - Cassini Solstice Mission Official WebSite (where the distance between the Spacecraft and Rhea is estimated to be 2.348 miles). Obviously, everybody - even our Friends from NASA - makes mistakes, every now and then...
This frame (which is an Original NASA - Cassini Spacecraft b/w image published on the NASA - Planetary Photojournal and identified by the serial n. PIA 14660) has been additionally processed, contrast enhanced, and then colorized 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 down, towards the Surface of the Saturnian moon Rhea), 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 on the Surface of Rhea, each having a different Albedo (---> Reflectivity) and Chemical Composition.
Note: it is possible (but we, as IPF, have no way to be one-hundred-percent sure of such a circumstance), that the actual luminosity of the Surface of Rhea - as it is presented in this image - would appear, to an average human eye, way lower than it has been shown (or, better yet: interpreted) here.MareKromium
(4 voti)
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Dione_and_Mimas-PIA14619-PCF-LXTT-IPF-1.jpgSo close, and yet so far... (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)82 visiteThe Saturnian moon Mimas peeps out from behind the larger moon Dione in this suggestive view of a so-called "Mutual Event" as it was seen from and recorded by the NASA - Cassini Spacecraft. Mimas (which is approx. 246 miles - such as a little less than 396 Km - across) is near the bottom center of the image. This view looks toward the anti-Saturn side of Dione (which is about 698 miles - such as approx 1123,3 Km - across). North on Dione is up and rotated 20° to the right.
The image was taken in Visible Light with the NASA - Cassini Spacecraft Narrow-Angle Camera on December 12, 2011, at a distance of approximately 377.000 miles (such as about 606.721 Km) from Mimas and approximately 56.000 miles (such as a little more than 90.000 Km) from Dione, at a Sun-Dione-Cassini Spacecraft , or Phase, Angle of 42°. Image scale is 1773 feet (such as about 540,41 meters) per pixel on Dione.
This frame (which is a crop from an Original NASA - Cassini Spacecraft b/w image published on the NASA - Planetary Photojournal with the ID n. PIA 14619) has been additionally processed and then colorized 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 Saturnian moons Dione and Mimas), 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 on the Surface of Dione and Mimas, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
(4 voti)
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Rhea-PIA14574-PCF-LXTT-IPF.jpgIn the Saturnshine (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunar Explorer Italia/Italian Planetary Foundation)135 visiteSome Southern Terrain on the Gas-Giant Planet Saturn's moon Rhea is dimly illuminated by the Saturnshine (---> the Saturnian equivalent, on Rhea, of the Moonshine, on Earth) in this NASA - Cassini Spacecraft's view of the dark side of the moon. The camera of Cassini is looking toward the night side of Rhea (which is approx. 1530 Km - such as about 950 miles - across), but the Sunlight reflected off the day side of the immense Saturn is bright enough to illuminate the Surface - with all its Impact Craters - seen here. This view is centered on Terrain located at 23° South Latitude and 315° West Longitude. If you look carefully beyond the Limb of Rhea, you will notice that 4 (four) background Stars are visible.
The image was taken in Visible Light with the NASA - Cassini Spacecraft Wide-Angle Camera on August, 1st, 2011. The view was obtained at a distance of approximately 6000 Km (such as about 3726 miles) from Rhea and at a Sun-Rhea-Cassini Spacecraft, or Phase, Angle of 113°. Scale in the original image was 800 meters (such as 2600 feet) per pixel.
This frame (which is an Original NASA - Cassini Spacecraft image published on the NASA - Planetary Photojournal with the ID n. PIA 14574) has been additionally processed, contrast enhanced, and then colorized 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 Saturnian moon Rhea), 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 on the Surface of Rhea, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
(4 voti)
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Dione-PIA14628-PCF-LXTT-IPF.jpgLarge Rayed Crater on Dione (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)93 visiteThe NASA - Cassini Spacecraft looks at an example of a Rayed Crater located on the Leading Hemisphere of the Saturnian moon Dione. The Rayed Crater is in the upper-left of the image and its Rays (made by Ejecta ---> such as by Rocky Material, belonging to Dione, that was lifted up and thrown away in every direction at the time of the Impact) show up as brighter material ("brighter" if compared to the Albedo of the Surface that surrounds it) which emanates from the Crater itself.
This view, as we said hereabove, looks toward the Leading Hemisphere of Dione (which is approx. 700 miles, such as about 1125 kilometers across). North on Dione is up and rotated 12 degrees to the left. The image was taken in Visible Light with the NASA - Cassini Spacecraft Narrow-Angle Camera on July 23, 2012. The view was acquired at a distance of approximately 260.000 miles (such as about 418.000 kilometers) from Dione and at a Sun-Dione-Spacecraft (or Phase) Angle of 5°. Image scale is about 2 miles (such as a little more than 3 kilometers) per pixel.
This frame (which is an Original NASA - Cassini Spacecraft image published on the NASA - Planetary Photojournal with the ID n. PIA 14628) has been additionally processed and then colorized 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 Saturnian moon Dione), 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 on the Surface of Dione, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
(4 voti)
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The_Rings-N00191994-N00192059-GB-LXTT-IPF.gifIn the Rings (a GIF-Movie by Dr Gianluigi Barca - Lunar Explorer Italia/Italian Planetary Foundation)100 visiteThe densest Regions of the Saturnian Ring System consist of the A and B-Rings, which are separated by the so-called "Cassini Division" (which was discovered in the AD 1675 by the Italian Astronomer Giovanni Domenico Cassini). Along with the C-Ring, which was discovered 75 years later (such as in the AD 1850), these three Regions together form the Main Rings of the Giant Gas Planet Saturn.
The Main Rings are denser and contain larger Water Ice and Rocky Particles than the very tenuous so-called Dusty Rings, which include the D-Ring (extending inward, towards Saturn's Cloud Tops), the G and E-Rings, as well as other and even more tenuous (or also "diffuse") Rings and Ringlets (and, perhaps, even some Ring Arcs) which are all located beyond the three Main Rings (which can also be named as the "Main Ring System").
These "Diffuse Rings" are known as "dusty" because of the extremely small size of the Water Ice and Dust Particles which form them (and whose size can often be in the order of just one or two micrometers). Last, but not least, the narrow F-Ring - which rotates just off the Outer Edge of the A-Ring - is the most difficult one to be categorized, and that is because some parts of it are very dense, while others are extremely tenuous.
The brightness and purity of the Water Ice contained in the Rings has been often cited as evidence that they should (and could very well be) much younger than Saturn (some Scientists say - but this is, of course, just a speculation - that their age could be of approx. 100 Million Years only, since the infall of Meteoric Dust would have led to some very obvious darkening of the Rings themselves, if they had been older. However, a new research also indicates that the B-Ring may be massive enough to have diluted the infalling Meteoric Dust Material and thus avoided any substantial darkening of the entire Ring System. In addition to the above, the material forming the Rings may also be periodically recycled, as "Clumps" form within the Rings and then are disrupted by occasional Impacts. This last theory, if proven correct, could substantially explain the apparent youth of some of the Material existing within the whole Ring System.
The NASA - Cassini - UVIS Team, led by Dr Larry Esposito, used the so-called "Stellar Occultation Method" to discover something like 13 (thirteen) new Celestial Objects, ranging from approx. 27 metres to about 10 Km across, and all located within the F-Ring. These Objects appear to be translucent, thus suggesting that they could be temporary aggregates of Water Ice Boulders, each one of them being a few meters across. Dr Esposito believes that this could be the Basic (Mechanical) Structure that allows the formation and (somehow periodic) renewal of the entire Saturnian Ring System, such as Water Ice and Rocky Dust Particles first clumping together, and then being - as we suggested, maybe occasionally, maybe periodically - blasted apart.MareKromium
(4 voti)
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The_Rings-N00191724-N00191763-GB-LXTT-IPF.gifIn the Rings (a GIF-Movie by Dr Gianluigi Barca - Lunar Explorer Italia/Italian Planetary Foundation)97 visiteOnce (actually, only a few decades ago...), we used to think that the Rings of the Gas-Giant Planet Saturn were something unique in the Universe. Now, after we have seen Rings and/or Ring-Arcs and Ringlets around each and every one of the other three Gas-Giant Planets Jupiter, Uranus and Neptune, we do know that the Rings of Saturn are just the Most Extensive (---> i.e.: the Widest) Planetary Ring System in the Solar System. The Rings of Saturn - according to the majority of the Planetary Scientists - mostly consist of countless, small particles of Ice and Dust (ranging, in size, from micrometres to a few metres), which orbit around Saturn. As a matter of fact, the Ring Particles are made almost entirely of Water Ice, with some contamination from Dust and - maybe - other (minor) Elements.
As everybody should know, although reflection from the Rings increases the brightness of Saturn, the Rings themselves are not visible from Earth with unaided vision. In the AD 1610, however (such as one year after the Italian Astronomer Galileo Galilei first turned a telescope to the Sky), the Rings of Saturn appeared in all their beauty and Galileo Galilei became the very first person to observe them, even though he could not see them well enough to discern their true nature. Afterwards, in the AD 1655, the Dutch Mathematician and Astronomer Christiaan Huygens was the first one to describe them as a Disk made by (some kind of) Material surrounding (---> orbiting around) Saturn. Although many people still believe that the Rings of Saturn are made by a series of tiny Ringlets (a concept that goes back to Laplace), it is way more correct to think of them (like some NASA Scientists recently suggested) as an Annular Disk with concentric Local Maxima and Minima in both Density and Brightness. The Rings have numerous Gaps where the Particles' Density drops sharply: two of these Gaps opened because of the action of small (and known) really small moons which are actually "embedded" within them, while many others are located in specific places where the Tidal Forces exercized by (resonating) Saturnian moons create a phenomenon of Gravitational Destabilization of entire regions of the Rings themselves. Stabilizing resonances, on the other hand, can be considered responsible for the stability (and longevity) of several Rings (think about, for instance, to the Titanian Ringlet and the G-Ring). Well beyond the Main Rings, there is the so-called "Phoebe Ring", which is tilted at an angle of 27° as to the other Rings and, just like Phoebe, orbits in a Retrograde fashion.
Furthermore, and just out of Intellectual Curiosity, we wish to highlight that we believe, as IPF, after we examined (in extreme detail) several hundreds of close-up pictures of the Rings which were all obtained during the last Saturnian Equinox, that there should (and could well) be a few (relatively wide) Regions of the Rings themselves that are NOT made by Orbiting Ice and Dust Particles, but rather by orbiting "Pavings", such as by Aggregated Particles of Ring Material that, since they were positioned/located in specific regions within the Rings where they neither did nor do suffer any - or, maybe, just a negligible - Tidal Stress, in time joined together and formed something like "Floating Rocky Slates" (which means, in other words, the "flat" equivalent of a so-called "rubble-pile" Asteroid).MareKromium
(4 voti)
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Dione-EB-MF-LXTT-IPF-2.jpgDione (Enhanced Natural Colors; credits for the additional process. and color.: Elisabetta Bonora and Marco Faccin)106 visitenessun commentoMareKromium
(4 voti)
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Hyperion-N00174824-N00174908-GB-LXTT.gifTumbling Hyperion (a GIF-Movie by Dr Gianluigi Barca - Lunexit Team)167 visitenessun commentoMareKromium
(4 voti)
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Helene-PIA12779-PCF-LXTT.jpgLike a "Cosmic Apple"... (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunar Explorer Italia)138 visiteCaption NASA:"Saturn's small, irregularly shaped moon Helene is strikingly illuminated in this close view captured by Cassini during the Spacecraft's June 18, 2011, Fly-By. Although it is not visible at this exposure, the Planet (Saturn?) actually fills the dark background of this image of Helene.
This view looks toward the anti-Saturn side of Helene (which is about 33 Km, or approx. 21 miles across). North on Helene is up. The lit Terrain on the right is on the Leading Hemisphere, while lit Terrain at the top of the image surrounds the North Pole.
This image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera. The view was obtained at a distance of approximately 11,000 kilometers (7,000 miles) from Helene and at a Sun-Helene-Spacecraft, or Phase, Angle of 151°.
Image scale is roughly 67 meters (220 feet) per pixel".MareKromium
(4 voti)
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Rhea-PIA12768-PCF-LXTT.jpgIntersecting Lineae on Rhea (Enhanced Natural Colors; credits for the additional process. and color: Dr Paolo C. Fienga - Lunexit Team)226 visiteCaption NASA:"Thin Lineaments cross back and forth on the Surface of Saturn's moon Rhea in this Equatorial View. These Lines can be seen intersecting Craters on Rhea. This view is centered on Terrain at about 0° Latitude and approx. 165° West Longitude.
The image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera on Jan. 11, 2011. The view was acquired at a distance of approx. 41.000 Km (such as 25.461 miles) from Rhea and at a Sun-Rhea-Spacecraft, or Phase, Angle of 15°. Image scale is roughly 238 meters (781 feet) per pixel".MareKromium
(4 voti)
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Japetus-N00091967-PCF-LXTT.jpgMountains and Craters of Japetus: proximities of the Transition Zone (Absolute Natural Colors; elab. by Dr Paolo C. Fienga - Lunexit Team) 246 visitenessun commentoMareKromium
(4 voti)
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