| Piú viste - Titan: The "Foggy" Moon |
Titan-PIA09034.jpgCloudless Titan...55 visiteCaption NASA originale:"This image is a composite of several images taken during two separate Titan flybys on Oct. 9 (T19) and Oct. 25 (T20), 2006.
The large circular feature near the center of Titan's disk may be the remnant of a very old impact basin. The mountain ranges to the South-East of the circular feature and the long dark, linear feature to the North-West of the old impact scar may have resulted from tectonic activity on Titan caused by the energy released when the impact occurred.
The Oct. 9 images form the background globe for context and the most recent images from the Oct. 25 flyby are overlaid. The Oct. 9 images were taken at an average distance of about 30,000 Km (approx. 18.000 miles). The Oct. 25 images were taken at a distance of 12.000 Km (about 7.200 miles). The images were taken at wavelengths of 1,3 microns shown in blue, 2 microns shown in green and 5 microns shown in red".MareKromium
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Titan-Regions-Fensal_and_Aztlan_Region-PIA08352.jpgFensal and Aztlan Region55 visiteAs Cassini continues its reconnoitering flybys of Titan, the imaging science team continues to improve its ability to tease out surface details hidden in the unprocessed images. This mosaic provides the best view yet obtained by Cassini's cameras, showing terrain on the moon's sub-Saturn Hemisphere -- the side of the moon that always faces toward Saturn. This mosaic has better resolution, both in pixel scale and from improved signal-to-noise, compared to previous views of the area.
"Signal-to-noise" is a term scientists use to refer to the amount of meaningful or useful information (signal) in their data versus the amount of background noise. A higher signal-to-noise ratio yields sharper, clearer views of Titan's surface.
The view is centered on terrain in the Fensal-Aztlan region on Titan, at 0,03° South Lat. and 22,18° West Long. The mosaic covers an area 3.500 Km (2.180 miles) North to South and 3.600 Km (2.240 miles) West to East. North is up.
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Titan-Surface-Unexplained_Surface_Features-PIA06111.jpgUnexplainable Surface Features55 visiteCaption NASA:"This image acquired at a range of 344.000 Km (about 213.700 miles) shows details at Titan's surface never seen before. The image shows only surface brightness no topographic shading. The finest features are less than 10 Km (a little more than 6 miles) across. In other areas the surface boundaries are less distinct perhaps due to different geologic process or atmospheric effects. There are some linear features that could be impact craters but the fact that many features are linear suggests that other geologic processes are shaping the surface".
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Titan-North_Polar_Regions-PIA09171.jpgStrong turbulence over Titan's North Pole55 visiteCaption NASA:"Cassini's VIMS (Visual and Infrared Mapping Spectrometer) has imaged a huge cloud system covering the North Pole of Titan.
This composite image shows the cloud, imaged at a distance of 90.000 Km (about 54.000 miles) during a Dec. 29, 2006, flyby designed to observe the limb of the moon. Cassini's VIMS scanned the limb, revealing this spectacular cloud system.
It covers the North Pole down to a Latitude of 62° North and at all observed Longitudes.
Such a cloud cover was expected, according to the atmospheric circulation models of Titan, but it had never been observed before with such details. The condensates may be the source of liquids that fill the lakes recently discovered by the radar instrument.
This image was color-coded, with blue, green and red at 2, 2,7 and 5 microns, respectively".
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Titan-Lakes-Unnamed_North_Polar_Lakes-07-PIA08363-1.jpgThe Great Lake of Titan (False Colors; elab. Lunexit)55 visiteCaption NASA:"This view of Titan taken on Feb. 25, 2007, reveals a giant lake-like feature in Titan's North Polar Region. It is approximately 1100 Km (about 680 miles) long and has a surface area slightly smaller than that of Earth's largest lake, the Caspian Sea".
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Titan-W00028749.jpgOn the "Dark Side" of Titan...55 visitenessun commentoMareKromium
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Titan-N00084850.jpgInterpreting Titan (5)55 visitenessun commentoMareKromium
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Titan-N00084842.jpgInterpreting Titan (4)55 visitenessun commentoMareKromium
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Titan-N00084809.jpgInterpreting Titan (3)55 visitenessun commentoMareKromium
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Titan-N00084802.jpgInterpreting Titan (2)55 visitenessun commentoMareKromium
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Titan-N00084796.jpgInterpreting Titan (1)55 visite"Interpretare Titano". Difficile. Molto difficile. L'osservazione visuale di quella che la NASA chiama "foggy moon" non è gratificante, a causa dell'estrema turbolenza che caratterizza l' (alta e media) atmosfera di questo Mondo. Le nuvole di sabbia (che dovrebbero apparire giallastre) si confondono con quelle formate da ghiaccio d'acqua e/o da altri elementi organici; le nebbie che coprono perpetuamente la superficie di questo misterioso ed affascinante pianeta contribuiscono ad aumentare le difficoltà a noi "Interpreti". Se a questo aggiungiamo la grande distanza dalla quale le immagini sono state ottenute e la presenza costante di artefatti, il nostro lavoro diventa quasi impossibile. Le sole certezze che abbiamo attengono la colorazione di Titano il quale, se da una certa distanza (osservazioni telescopiche terrestri ed HST incluse) appare giallo, a mano a mano che ci si avvicina sembra "cedere" il colorito giallo in favore di varie gradazioni di celeste pallido, verde chiaro e marrone chiazzato.
Molte di queste colorazioni (dal celeste pallido, al giallo/arancio, al blu), forse, sono una conseguenza dell'interazione fra la debole (ma non insignificante!) illuminazione solare e gli elementi che compongono gli strati alti dell'atmosfera di Titano; altre di queste colorazioni (i verdi, i giallo-scuri, i bianchi ed i marroni), invece, potrebbero essere proprie degli strati bassi e/o (addirittura) della superficie di questo Mondo.
E noi...Noi interpretiamo. O meglio: proviamo ad interpretare...MareKromium
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Titan-Regions-Adiri_Region-PIA08995.jpgFlying over Adiri55 visiteCaption NASA:"Within the windswept wastes of Titan's Equatorial Dune Desert lies the 1.700-Km (1.050-mi) wide bright Region called Adiri, seen here at center.
The intrepid Huygens probe landed off the North-Eastern edge of Adiri in January 2005.
This view looks toward the Anti-Saturn side of Titan (5.150 Km, or about 3.200 miles across) -- the side that always faces away from Saturn as the moon orbits. North on Titan is up and rotated 26° to the right.
The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 939 nanometers. The view was acquired with the Cassini spacecraft wide-angle camera on June 14, 2007 at a distance of approx. 157.000 Km (about 98.000 miles) from Titan. Image scale is roughly 9 Km (about 6 miles) per pixel".MareKromium
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