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Titan-PIA06996_modest.jpgDoes Titan have a so-called "weather-pattern"?57 visiteIn the first image (left), obtained on the 1st Titan flyby, from a distance of 200.000 Km, Titan's skies are cloud-free, except for a patch of clouds observed over the South Pole near the bottom of the image. In contrast, the image on the right shows a recent view of this same area of Titan obtained 7 weeks later on the 2nd close Titan flyby, from a distance of 225.000 Km. This image clearly shows that several extensive patches of clouds have formed over temperate latitudes. The appearance of these clouds reveals the existence of weather. Tracking these features is currently underway by scientists, who hope to gain a better understanding of global circulation, regional weather patterns and localized meteorology in Titan's skies. The red color images the surface at a wavelength (2.01 micron) where the surface is relatively bright, making the surface appear reddish in these color images. The green color (2.83 micron) images the surface as well, but due to enhanced absorption of sunlight by the surface and lower atmosphere, the surface is relatively dark here compared to the red. The blue color (2.13 micron) is at a wavelength where sunlight cannot reach the surface at all due to strong absorption by the atmospheric gas methane. In contrast to the reddish surface, bright clouds at a relatively high altitude (here, about 30 kilometers (19 miles) above the ground) residing above most of the atmospheric absorption appear whitish in these representations, as they reflect sunlight effectively in all three near-infrared colors.
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Titan-PIA06997_modest.jpgHaze Silhouettes Against Titan's Glow56 visite"A high-altitude haze layer residing some 400 Km above the surface of Titan is seen here traced along the limb of Titan as silhouetted against the glow of Titan's atmosphere produced by the fluorescence of methane gas. This detached haze layer can be seen as a dark lane imbedded within the gold-colored fluorescent layers of Titan. This image of Titan's limb and surface was obtained on Dec. 13, 2004 from a vantage point some 158.000 Km above the night side of Titan, at a phase angle of 161°. Beneath the fluorescence, Titan's surface at the extreme limb can be seen in blue color, illuminated by 5-micron wavelength sunlight that penetrates the thick atmosphere and hazes to reflect off the limb of Titan. The darkness of the silhouetted haze layer comprised of relatively small particles suggests that the particles themselves absorb strongly at the fluorescent wavelength and thus are possibly comprised of relatively complex hydrocarbon aerosols generated by photochemical processes in Titan's upper atmosphere".
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Titan-PIA07542-PCF-LXTT.jpgTitan (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)163 visitenessun commentoMareKromium
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Titan-PIA07565.jpgTitan's Terminator...from about 1,3 MKM54 visiteTitan's equatorial latitudes are distinctly different in character from its South Polar Region, as this image shows. The dark terrain, presumably lowland, seen here does not extend much farther south than about 30° South. The successful Huygens probe landed in such a Region. The Huygens probe is rotating into the light here, seeing the dawn of a new day. The bright region toward the right side of Titan's disk is Xanadu. This area is thought to consist of upland terrain that is relatively uncontaminated by the dark material that fills the lowland regions.
Near the South Pole, and just eastward of the terminator, is the dark feature identified by imaging scientists as the best candidate (so far) for a past or present hydrocarbon lake on Titan (see PIA06241). Farther east of the lake-like feature, bright clouds arc around the Pole. These clouds occupy a latitude range that is consistent with previously-seen convective cloud activity on Titan. The phase angle is 60° while the image scale is 7 Km per pixel.
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Titan-PIA07626.jpgThe "haze" of Titan59 visiteOriginal caption:"Looking back toward the sun brings out the thin haze that hovers 500 Km (310 miles) above Saturn's moon Titan.
The haze is composed of small particles whose diameter is comparable to the wavelength of light, which is ultraviolet light centered at 338 nnmts. Particles of this scale scatter sunlight most effectively in the direction opposite to the direction of sunlight itself.
Scientists are still trying to understand what processes produce this thin, high-altitude haze layer.
Picture data: North on Titan is up and tilted 10° to the right. The image was taken with the Cassini spacecraft narrow-angle camera on Sept. 24, 2005, at a distance of approx. 917.000 Km (about 570.000 miles) from Titan and at a Sun-Titan-spacecraft angle of 145°. Image scale is 5 Km (about 3 miles) per pixel".
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Titan-PIA07700.jpgThe Atmosphere of Titan54 visiteThe view of Titan (almost natural colors) has been greatly contrast-enhanced to better show some intriguing structure in the North of the Planet; such intriguing "clouds-structure" is also clearly visible in a violet light view (PIA07701) taken at about the same time.
The color view was created by combining images taken using red, green and blue spectral filters. The images were taken with the Cassini spacecraft wide-angle camera on Dec. 26, 2005, at a distance of approx. 193.000 Km (about 120.000 miles) from Titan and at a phase angle of 29°. The image scale is about 11 Km (roughly 7 miles) per pixel.
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Titan-PIA07701~0.jpgThe atmosphere of Titan54 visiteThis view of Titan reveals structure in the moon's complex atmosphere. The geometry of the Cassini spacecraft's view of Titan during this flyby was similar to that of Voyager 1's pass in 1980.
The image was taken in visible violet light and shows the detached high haze layer that envelops Titan, with additional complexity to its structure in the far North. Some of this atmospheric structure is also visible in a color view (PIA07700) taken at about the same time..
The image was taken with the Cassini spacecraft wide-angle camera on Dec. 26, 2005, at a distance of approx. 194.000 Km (such as about 121.000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 29°. The image scale is 11 Km (about 7 miles) per pixel.
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Titan-PIA07707.jpgSmiling Titan...54 visiteThis infrared view shows features on the Leading Hemisphere of Titan, including the bright, crescent-shaped Hotei Arcus (right of center), which is also informally called "the Smile" by researchers.
The view is centered on the bright Region called Xanadu. Above center is the large crater Minerva, which is surrounded by darker material.
This image was taken with the Cassini spacecraft narrow-angle camera on Jan. 13, 2006 using a spectral filter sensitive to wavelengths of infrared light centered at 938 nnmts. The image was acquired at a distance of approx. 1,3 MKM (800.000 miles) from Titan and at a phase angle of 41°. Image scale is about 7 Km (approx. 5 miles) per pixel.
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Titan-PIA07729.jpgTitan, from about 213.000 Km (natural colors)55 visiteAs Cassini approached Titan on Aug. 21, 2005, it captured this natural color view of the moon's orange (nota: veramente, a parte i nostri occhi - che, come tutti sanno, possono sbagliare -, il software che utilizziamo per valutare la densità cromatica dei frames NASA che pubblichiamo e che ci permette altresì di identificare i 'colori maggiori' che sono presenti in essi ci dice che il colore dominante è il "giallo"...), global smog. Titan's hazy atmosphere was frustrating to NASA Voyager scientists during the first tantalizing Titan flybys 25 years ago, but now Titan's surface is being revealed by Cassini with startling clarity (...).
Images taken with the wide-angle camera using red, green and blue spectral filters were combined to create this color view. The images were acquired at a distance of approximately 213.000 Km from Titan and at a Sun-Titan-spacecraft, or phase, angle of 55°. Resolution in the image is about 13 Km per pixel.
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Titan-PIA07730.jpgTitan, from about 159.000 Km54 visiteThis processed image from Cassini's Aug. 22, 2005, flyby of Titan reveals mid-latitudes on the Moon's Saturn-facing side.
Provisional names recently have been applied to a number of features on Titan. Features within the Region seen here - long known informally as the "H" - now have names like Tsegihi, Aztlan and Quivira.
The bright 215-Km-wide feature provisionally named "Bazaruto Facula" is clearly visible right of center, with its dark, unnamed 80-Km-wide crater at its center.
This view was acquired with the wide-angle camera at a distance of approx. 159.000 Km from Titan using a spectral filter centered on infrared wavelengths at 939 nnmts. The image scale is 9 Km per pixel.
Previous observations indicate that, due to Titan's thick and very hazy atmosphere, the sizes of surface features that can be resolved are a few times larger than the actual pixel scale.
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Titan-PIA07774.jpgCrescent Titan54 visiteWith its thick, distended atmosphere, Titan's orange globe shines softly, encircled by a thin halo of purple light-scattering haze. Images taken using blue, green and red spectral filters were used to create this enhanced-color view; the color images were combined with an ultraviolet view that makes the high-altitude, detached layer of haze visible.
The ultraviolet part of the composite image was given a purplish hue to match the bluish-purple color of the upper atmospheric haze seen in visible light.
Small particles that populate high hazes in Titan's atmosphere scatter short wavelengths more efficiently than longer visible or infrared wavelengths, so the best possible observations of the detached layer are made in ultraviolet light.
The images in this view were taken by the Cassini narrow-angle camera on May 5, 2005, at a distance of approx. 1,4 MKM (about 900.000 miles) from Titan and at a phase angle of 137°.
Image scale is 8 Km (5 miles) per pixel.
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Titan-PIA07876.jpgA bright Red Spot on Titan (1)54 visiteThe recently discovered infrared-bright spot on Titan is the type of enigmatic feature that is best investigated by putting together as many different types of complementary information as possible. This montage shows the spot in infrared wavelengths from the visual and infrared mapping spectrometer on the left, from the imaging science subsystem in the center and a combination of both data sets on the right. When put together, the 2 different views show more than either does separately. The visual and infrared spectrometer team noted the bright region in the image on the left after March 31, 2004, Cassini's-Titan encounter. The strange, bright feature to the southeast of Xanadu was flagged as unusual and informally dubbed "The Smile" by imaging team members in December 2004. It seems clear that both instruments are detecting the same basic feature on Titan's surface. This bright patch may be due to an impact event, landslide, cryovolcanism, or atmospheric processes. Its distinct color and brightness suggest that it may have formed relatively recently".
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