| Piú votate - Titan: The "Foggy" Moon |
Titan-Atmosphere-PIA06182.jpgOver the Clouds of Titan57 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".
(5 voti)
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Titan-Craters-Unnamed_Crater-Radar_Mapping-PIA07365-br500-01.jpgImpact Crater?57 visiteCaption NASA originale:"A huge annular feature with an outer diameter of approximately 440 kM (approx. 273 miles) appears in this image taken with Cassini's Titan radar mapper. It resembles a large crater or part of a ringed basin, either of which could be formed when a comet or asteroid tens of Kms in size slammed into Titan. This is the first impact feature identified in radar images of Titan. The surface of Titan appears to be very young compared to other Saturnian satellites. In Titan's case, debris raining down from the atmosphere or other geologic processes may mask or remove the craters. The pattern of brightness suggests that there is topography associated with this feature; for example, in the center of the image there appear to be mounds each about 25 Km across. Since they are dark on their lower edges that face away from the radar and bright on the opposite face, they must be elevated above the surrounding terrain".
(5 voti)
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Titan-Huygens_Landing_Site-06.jpgThe "Landing Site": a new best estimate56 visiteCaption NASA originale:"A view of Titan from the visual and infrared mapping spectrometer instrument on the Cassini orbiter. The Huygens probe landed in the small red circle on the boundary of the bright and dark regions. The size of the circle shows the field of view of the Huygens Descent Imager/Spectral Radiometer (DISR) instrument from an altitude of 20 Km (about 12 miles)".
(5 voti)
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Titan-Surface-32.pngOn the surface of Titan73 visiteCaption ESA originale:"This raw image was returned yesterday, 14 January 2005, by ESA's Huygens probe during its successful descent to land on Titan. Sizes have been added to indicate scale of these features. Initially thought to be rocks or ice blocks, they are more pebble-sized. The two rock-like objects just below the middle of the image are about 15 cm (left) and 4 cm (centre) across respectively, at a distance of about 85 cm from Huygens. The surface is darker than originally expected, consisting of a mixture of water and hydrocarbon ice. There is also evidence of erosion at the base of these objects, indicating possible fluvial activity".
(5 voti)
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Titan-Shoreline_and_Drainage_Channels-03.jpgShoreline and Drainage Channels58 visiteCaption ESA originale:"This is one of the first raw images returned by the ESA Huygens probe during its successful descent.It was taken at an altitude of 8 Km with a resolution of 20 metres per pixel. It shows what could be the landing site, with shorelines and boundaries between raised ground and flooded plains".
(5 voti)
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Titan-Atmosphere-PIA06160_modest.jpgThe many layers of Titan's Atmosphere56 visiteCaption NASA originale:"Cassini has found Titan's upper atmosphere to consist of a surprising number of layers of haze, as shown in this ultraviolet image of Titan's night side limb, colorized to look like true color. The many fine haze layers extend several hundred kilometers above the surface. Although this is a night side view, with only a thin crescent receiving direct sunlight, the haze layers are bright from light scattered through the atmosphere. The image was taken with the Cassini spacecraft narrow angle camera. About 12 distinct haze layers can be seen in this image, with a scale of 0.7 Km (0.43 miles) per pixel. The limb shown here is at about 10° south latitude, in the equatorial region".
(5 voti)
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Titan-Clouds-PIA06158.jpgTitanian Clouds (October 2004 fly-by)56 visiteCaption NASA originale:"Cutting through the middle of the image is a sharp boundary between the bright region known as Xanadu Regio on the right and dark terrain to the left. Several smaller bright features, between 30 and 200 Km across are seen within the dark terrain. These intriguing features are a focus of further research and observations for Cassini scientists. One clue to their origin and history is the presence of bright "trails" within the dark material on the eastern sides of the bright spots. A mottled texture is seen within Xanadu, including dark, crisscrossing lines, suggestive of tectonic activity. No definitive craters have been found in these images, though several bright rings or circular features are seen in the dark terrain. However, without topographic shading, their identification as impact structures can not be confirmed. The images in this mosaic have been processed to enhance surface features and sharpen boundaries".
(5 voti)
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Titan-PIA06982_modest.jpgTitan from 1.200 Km54 visiteCaption NASA originale:"These images show the surface of Titan at two different infrared wavelengths. They were captured by the visual and infrared mapping spectrometer onboard Cassini as the spacecraft flew by at an altitude of 1200 Km - Cassini's closest approach yet to the Hazy Moon. The image on the left, taken at a wavelength of 2 microns, is the most detailed picture to date of the Titan's surface. It reveals complex landforms with sharp boundaries, which scientists are eager to further study. The image on the right was taken at a wavelength of 1 micron and shows approximately what a digital camera might see". Ad essere sinceri, da queste primissime immagini ravvicinate non riusciamo a distinguere praticamente nulla. Dobbiamo attendere che al Controllo Missione elaborino meglio le immagini giunte sino ad ora prima di lanciarci in nuove speculazioni relative alla configurazione effettiva della superficie di Titano. Abbiamo atteso anni, possiamo aspettare ancora qualche settimana...
(5 voti)
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Titan-PIA06138_modest.jpgTitan: the anomalous "circular" surface features are "camera artifacts"54 visiteCaption NASA originale from Planetary Photojournal:"The large, bottom image shows a complex interplay between dark and bright material on Titan's surface. This image was taken at a range of about 340.000 Km and the entire view is approximately 2.000 Km across. The surface appears to have been shaped by multiple geologic processes. Although a few "circular features" can be seen, there are no features that can be definitively identified as impact craters. The 3 smaller images show details of some of the features seen within the larger scene. The image on the upper right shows a scene approximately 500 Km across in which bright and dark bands of material span Et to Wt. The upper middle and upper right images show bright material surrounded by dark material in scenes approximately 300 Km across. The dark circular feature that appears at the top of each of the upper images is an artifact that was not removed by the preliminary image processing. There are no shadows or topographic shading visible in these images".
(5 voti)
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Titan-PIA06139.jpgTitan (false colors)53 visiteDa "NASA - Picture of the Day" del 28.10.2004:"Normally hidden by a thick, hazy atmosphere, tantalizing features on Titan's surface appear in this false-color view. The image was recorded as the Cassini spacecraft approached its first close flyby of Saturn's smog-shrouded moon on October 26. Here, red and green colors represent specific infrared wavelengths absorbed by Titan's atmospheric methane while bright and dark surface areas are revealed in a more penetrating infrared band. Ultraviolet data showing the extensive upper atmosphere and haze layers is seen as blue. Sprawling across the 5.000 Km wide moon, the bright continent-sized feature known as "Xanadu" is near picture center, bordered at the left by contrasting dark terrain.
Saturn orbiter Cassini and Titan lander Huygens plan further explorations, but for now the origin and nature of Titan's surface features remain unknown".
...Unknown, per ora, diciamo noi...
(5 voti)
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Titan-Close Up 1.jpgTitan's fly-by "A" - Close-up 157 visiteLe primissime immagini del Passaggio Ravvicinato (fly-by) "A" della Sonda Cassini-Huygens accanto a Titano. Non abbiamo i dati telemetrici relativi a questa immagine, ma certamente siamo ancora molto lontani dal punto di maggior vicinanza fra i due corpi (in questo momento ci troviamo, probabilmente, fra i 400 ed i 500.000 Km di distanza da Titano). Il "passaggio radente" (si fa per dire...) di Cassini-Huygens accanto a Titano per questo primo fly-by (contraddistinto dalla lettera "A") avverrà con il transito della Sonda ad una distanza di circa 1.200/1.300 Km dalla "Luna Nebbiosa" (Hazy-Moon). Un "niente", effettivamente, laddove paragonato alle distanze che Cassini-Huygens ha coperto (e sta ancora coprendo) per fare questa "passeggiata" nel Regno di Saturno...
(5 voti)
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Titan-PIA06125_modest.jpgTitan's fly-by "A"53 visiteCaption originale tratta dal Sito "Cassini-Huygens": "These 3 pictures were created from a sequence of images acquired by Cassini's imaging science subsystem on Oct. 25, 2004, 38 hours before its closest approach to Titan. (...) The processed images reveal sharp boundaries between dark and light regions on the surface; there are no shadows produced by topography in these images. The bright area on the center right is Xanadu, a region that has been observed previously from Earth and by Cassini. To the west of Xanadu lies an area of dark material that completely surrounds brighter features in some places. Narrow linear features, both dark and bright, can also be seen. It is not clear what geologic processes created these features, although it seems clear that the surface is being shaped by more than impact craters alone".
(5 voti)
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