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Titan-Atmosphere-PIA06182.jpgOver the Clouds of Titan54 visiteCaption NASA originale:"This image was taken during Cassini's 3rd close approach to Titan on Feb. 15, 2005.
The image was taken with the Cassini spacecraft narrow angle camera through a filter sensitive to wavelengths of polarized infrared light centered at 338 nanometers. The image was acquired at a distance of approximately 151.000 Km (approx. 94.000 miles) from Titan and at a phase angle of 20°.
Resolution in the image is about 900 meters (approx. 3.000 feet) per pixel".
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Titan-Atmosphere-PIA06224.jpgThe "Hig-Haze Layers" of Titan54 visiteCaption NASA originale:"Titan's "High Haze Layers" are amazing. Cassini captured this detailed view of the relatively faint haze in Titan's upper atmosphere as it receded from its close encounter on March 31, 2005. Similar examples of such complex structures in Titan's haze have been observed previously by Cassini. These observations will help reveal the processes responsible for forming the numerous layers that we see and how the structure and behavior of the layers change on daily and seasonal time scales.
The image was taken with the Cassini spacecraft narrow-angle camera using a filter sensitive to wavelengths of ultraviolet light centered at 338 nnmts and at a distance of 102.320 Km from Titan. Image scale is about 600 mt per pixel".
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Titan-Atmosphere-PIA06236.jpgThe Atmosphere of Titan55 visiteCaption NASA originale:"This natural color image shows Titan's upper atmosphere: an active place where methane molecules are being broken apart by solar ultraviolet light and the byproducts combine to form compounds like ethane and acetylene. The haze preferentially scatters blue and ultraviolet wavelengths of light, making its complex layered structure more easily visible at the shorter wavelengths used in this image. Lower down in the atmosphere, the haze turns into a globe-enshrouding smog of complex organic molecules. This thick, orange-colored haze absorbs visible sunlight, allowing only perhaps 10% of the light to reach the surface. The thick haze is also inefficient at holding in and then re-radiating infrared (thermal) energy back down to the surface. Thus, despite the fact that Titan has a thicker atmosphere than Earth, the thick global haze causes the greenhouse effect there to be somewhat weaker than it is on Earth".
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Titan-Atmosphere-PIA09823-PCF-LXTT.jpgTitan's Upper Atmosphere (Enhanced Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)71 visitenessun commentoMareKromium
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Titan-Atmosphere.jpgAtmospheres...54 visitenessun commento
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Titan-Atmosphere_and_Haze-00.jpgTitan from approx. 789.000 Km (The "Double Purple Haze")59 visitenessun commento
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Titan-CB3-CB2-MT3-EB-LXTT.jpgTechnicolored Titan (False Colors; credits for the additional process. and color.: Elisabetta Bonora - Lunexit Team)67 visitenessun commentoMareKromium
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Titan-Channels-Drainage_Channels-PIA07236-01.jpgWater Ice and Methane Springs on Titan55 visiteCaption NASA originale:"A single Huygens DISR image that shows two new features on the surface of Titan. A bright linear feature suggests an area where water ice may have been extruded onto the surface. Also visible are short, stubby dark channels that may have been formed by 'springs' of liquid methane rather than methane rain".
Come mai, qualcuno si è chiesto, gli idrocarburi di Titano non sono completamente ghiacciati? Come mai - almeno a quanto ci è dato vedere - i "fiumi" e le "sorgenti" di idrocarburi di Titano, rispettivamente, scorrono e zampillano? Che cosa permette alla superficie di Titano di essere sufficientemente calda da consentire a questo incredibile mondo di essere - da un certo punto di vista - "vivo e vitale"?
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Titan-Channels-Unnamed_Channels-PIA03564.jpgCanyonland on Titan54 visiteFluids have flowed and cut these deeply-incised channels into the icy surface of Titan as seen in this SAR image. The channels are roughly 1 Km across (about 0,6 miles) and perhaps 200 mt deep (about 650 feet); some can be traced as far as 200 Km (about 120 miles). Many of them have angular segments suggesting they may follow faults in Titan's crust.
Taken together with the two other radar passes (October 2004 and February 2005), these very HR images have identified at least two distinct types of drainage and channel formation on Titan. The style shown in this image consists of long valleys following angular patterns without many tributaries, suggesting that fluids flow over great distances.
This Cassini radar image was acquired as a part of the Titan flyby observations taken on Sept. 7, 2005, from a distance of about 2000 Km. The area is located at about 55° South Latitude, 7,5° West Longitude and extends over 300 km (about 186 miles) right to left.
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Titan-Channels-Unnamed_Channels-PIA03565.jpgTitan's rainfall?!?54 visiteIn contrast to the image "Canyonlands on Titan", this bright terrain is cut by channels that are variable in width; they form both radial and branching networks and such patterns are reminiscent of networks formed by rainfall on Earth.
At the bottom of the frame, the channels radiate from a possible source into a dark, smooth region that seems flatter and more plains-like. One interpretation is that the higher, rougher terrain has been cleansed of organic debris and eroded by methane rainfall. The removed material has then been deposited into the lower plains.
This Cassini SAR image of Titan was taken on Sept. 7, 2005, at a distance of 2000 Km from Titan. It is located near 48° South Latitude, 14° West Longitude and extends about 240 Km right to left.
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Titan-Channels-Unnamed_Channels-PIA10956.jpgXanadu's Channels (false colors; credits: Lunexit)55 visiteOn the final flyby of Cassini's original 4-year tour, its radar mapper captured these unusual channels on Titan at the edge of Xanadu, the widest seen in this area (For a radar image of Xanadu, see PIA08428). These might be active rivers carrying methane or debris, or they might be dry riverbeds similar to earthly "arroyos".
Past Cassini radar images have revealed different types of channels on Titan's surface (see PIA03565 and PIA07366). They vary from bright to dark in radar (rough to smooth), and from fan-shaped to braided to meandering.
Some, drain into lakes; others disappear. Some of these channels may be several hundred meters, or feet, deep.
This image, taken from the flyby on May 28, 2008, shows the border of Xanadu as the bright-dark boundary running from the upper left to lower right. Southward from that boundary is an unusual set of channels. While these are brighter (more roughly textured) than the surrounding terrain, some are only slightly brighter, and some are as wide as 5 Km (about 3 miles) — about the size of the River Thames at its mouth east of London.
They appear to flow out of the rough Region of Xanadu.
Careful inspection reveals smaller tributaries that wind through the brighter and apparently rougher terrain to the north. A close-up of one of the widest channels is shown at the lower left.
Scientists think that many of the channels on Titan are carved by methane deposited on the surface from strong but infrequent rainstorms. A bright channel may be dry, with the rough riverbed of icy particles (like those seen at the Huygens Landing Site) producing the radar brightness. The darker channels in this image resemble the dry lakes seen in the North Polar area of Titan, so they may be dry as well, with their smoother (radar-dark) surfaces caused by finer-grained sediment deposits on the channel floors.
This image shows an area located at 15° South Latitude and 121° West Longitude. It is about 450 Km (about 280 miles) across, and has approximately 1 Km (0,62-mile) resolution.
North is up.MareKromium
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Titan-Channels-Unnamed_Channels-Radar_Mapping-PIA07009.jpgChannels on Titan or just Windstreaks?55 visiteCaption NASA originale:"Running across the image (about 300 Km across) are a series of roughly parallel, mostly east-west dark linear features that join and separate, which are not seen in the previous radar images. They may be formed by the action of eastward-flowing winds, or geologic processes acting on the crust itself. In places they cut through adjacent terrain, while elsewhere the lineaments seem to be interrupted by brighter material, appearing again on the other side. Seams between radar segments are visible as horizontal, sawtooth-shaped lines. Bright material in radar images may be rough or sloped toward the radar (which is observing from the top in this frame). Also, some of what is seen may in fact be below the surface, revealed as the radio waves penetrate overlying, radar-transparent material".
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