| Piú votate - Titan: The "Foggy" Moon |
Titan-Regions-Hotei_Arcus_Region-PIA11839-2.jpgHotei Arcus in InfraRed (False Colors; credits: NASA/JPL/Space Science Institute)60 visitenessun commentoMareKromium
(5 voti)
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Titan-N00051529-1.jpgThrough the Titanian Clouds... (credits: Dr M. Faccin)55 visitenessun commentoMareKromium
(5 voti)
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Titan-Map-Wind_Patterns-PIA11801.jpgMapping Titan's Global Wind Patterns54 visiteScientists have used data from the Cassini Radar Mapper to map the Global Wind Pattern on Saturn's moon Titan using data collected over a four-year period, as depicted in this image.
The arrows indicate the direction in which sand is inferred to be transported along dunes observed in Titan radar data.
Underlying the arrows is a base map (PIA08399) from Cassini's Imaging Science Subsystem.
Many of the equatorial dark areas without arrows might have dunes but have not yet been imaged with radar. The dune orientations represent only the net effect of winds. It could be that sand transport only occurs on rare occasions, and winds from different directions can combine to yield the observed dune orientations.MareKromium
(5 voti)
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Titan-Regions-Senkyo_and_Aaru_Region-PIA10565.jpgSenkyo and Aaru Region81 visiteCaption NASA:"Named for other-worldly Paradises, the dark regions of Senkyo and Aaru comprise the center of this image of Saturn's moon Titan. The Egyptian fields of Aaru were Paradise for the god Osiris. This side of Titan, which always faces Saturn, is on the opposite side of the moon from Shangri-La and Adiri, the home to the Huygens probe.
The craft touched down on the border between the lowland dunes of Shangri-La and the higher terrains of Adiri. Like Senkyo and Aaru, these Regions' namesakes reflect heavenly aspirations. North is up in this image.
Senkyo is the Equatorial Region to the right of the center of the image. Aaru is above Senkyo.
The image was taken with the Cassini Spacecraft narrow-angle camera on Dec. 12, 2008 using a spectral filter sensitive to wavelengths of infrared light centered at 938 nanometers.The view was acquired at a distance of approx. 2,4 MKM (such as about 1,5 MMs) from Titan and at a Phase Angle of 35°.
Image scale is roughly 14 Km (about 9 miles) per pixel".MareKromium
(5 voti)
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Titan-Clouds-Noctilucent_Clouds-GIFMovie-N00023501-N00023599.gifNoctilucent Clouds over Titan (GIF-Movie; credits: Dr G. Barca)55 visiteSu Titano è notte, ma come queste immagini (ottimamente montate a formare un GIF-Movie dal nostro Dr Gianluigi Barca) dimostrano piuttosto chiaramente, delle grandi e vaporose formazioni nuvolose passano attraverso gli occhi elettronici di Cassini e si rendono palesi.
Magia delle riprese IR?
No, perchè queste immagini sono state ottenute nello Spettro della Luce Visibile.
E allora, come spiegare la (ripetiamo: EVIDENTE) luminosità delle nuvole di Titano?
Beh, esistono almeno tre modi per provare a spiegare (sensatamente) questo intrigante ed affascinante fenomeno, ma la soluzione (puramente ed assolutamente teorica e speculativa, lo sappiamo) che ci piace privilegiare la potete trovare descritta nell'articolo "Oltre la Nebbia", pubblicato sul nostro Blog "True Planets"...
MareKromium
(5 voti)
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Titan-Surface-38.gifOn the way down... - Sol 1 (GIF-Movie; credits: Dr G. Barca)55 visiteLe Condizioni di Illuminazione
Innanzitutto, ed a dispetto di quanto mostrato dalle immagini ESA-Huygens (e da tante altre “visioni artistiche” di Titano made by NASA, la nostra prima considerazione attiene le condizioni medie di illuminazione di questo mondo.
Le fotografie ESA (ottenute sia durante la discesa, sia dalla superficie di Titano), al pari delle interpretazioni artistiche NASA, ci danno l’impressione di un mondo, ancora una volta, alquanto luminoso…
MareKromium
(5 voti)
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Titan-Surface-36.gifOn the Surface... - Sol 1 (GIF-Movie; credits: Dr G. Barca)55 visiteLa consistenza apparente (e cioè sulla base dell’osservazione visuale diretta) del suolo di Titano suggerisce quella della sabbia umida e ciò ha fatto pensare che il terreno su cui si è poggiata la Huygens Probe possa essere periodicamente (rectius: frequentemente) soggetto al passaggio di liquidi.
Ad onor del vero, le immagini della superficie di Titano ottenute da Huygens – certo suggestive, ma poche e di mediocre qualità – non ci sono state di grande aiuto per comprendere in maniera adeguata la realtà superficiale di Titano e quindi, per fornire al Lettore un’idea di quello che un ipotetico astronauta potrebbe realmente vedere in seguito ad un Landing sulla “Luna Nebbiosa”, abbiamo dovuto fare ricorso ad una serie di riflessioni e speculazioni.
MareKromium
(5 voti)
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Titan-PIA10503.jpgLooking for Clouds... (IR - natural - but enhanced - colors; credits: Lunexit)90 visiteCaption NASA:"The Cassini Spacecraft peeks through the murk of Titan's thick atmosphere in a search for clouds. Although there are no obvious cloud features in this view, bright cloud streaks have occasionally been seen by Cassini and Earth-based telescopes in the region seen here toward the bottom of Titan's disk. Repeated monitoring observations like this one help scientists build an understanding of Titan's weather and the various climate processes operating on this frigid, but remarkably Earth-like moon.
This view looks toward the Saturn-facing Side of Titan (5150 kilometers, or 3200 miles across). North is up and rotated 35° to the left.
The image was taken with the Cassini Spacecraft narrow-angle camera on Sept. 25, 2008 using a spectral filter sensitive to wavelengths of Infrared Light centered at 938 nanometers. The view was acquired at a distance of approx. 1,7 MKM (such as about 1 MMs) from Titan.
Image scale is roughly 10 Km (approx. 6 miles) per pixel".MareKromium
(5 voti)
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Titan-Clouds-North_Polar_Clouds-PIA10434.jpgPolar Clouds on Titan (IR View - False Colors; credits: Lunexit)103 visiteCaption NASA:"Frigid Titan continues to prove itself a remarkably complex and dynamic world. Here, bright clouds are seen encircling the moon's North Polar Region.
The Cassini Spacecraft has revealed the presence of great lakes and seas of liquid hydrocarbons on this part of Titan's surface (see PIA08365 and PIA08930).
An extended, high-altitude haze hovers above the limb of Titan at top of the image.
The image was taken with the Cassini Spacecraft narrow-angle camera on April 26, 2008 using a spectral filter sensitive to wavelengths of Infrared Light centered at 938 nanometers. The view was acquired at a distance of approx. 786.000 Km (such as about 488.000 miles) from Titan.
Image scale is roughly 5 Km (a little more than 3 miles) per pixel".MareKromium
(5 voti)
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Titan-Mountains-PIA10654.jpgTitanian Tectonics - radio-image; credits: NASA54 visiteOvviamente la "linea" è un ovvio image-artifact, come la NASA stessa ci riferisce e spiega NELLE ULTIME DUE RIGHE DEI COMMENTI UFFICIALI, ma noi abbiamo lasciato la sovraimpressione "evocativa di Mistero" sul frame al SOLO scopo di farVi capire - caso mai ce ne fosse stato ancora bisogno - QUANTO SIA FACILE CREARE BUFALE!
Soprattutto allorchè NON si presta la dovuta attenzione alle note "ufficiali" di commento ed allorchè non si è molto familiari con la Fotografia Spaziale in generale e con le Radio-Immagini in particolare.
Caption NASA:"A set of three parallel ridges was seen by the Cassini Spacecraft's Radar Instrument during the latest Titan flyby on May 12, 2008. This combination is unlikely to be a coincidence -- the best explanation for these features is that they are tilted or separated blocks of broken or faulted crust, now exposed as high ridges. Their regular spacing is typical of regions that have been compressed or extended over large areas; as an example, the western United States Basin and Range Province was formed by extension. Such interactions are called "Tectonics", although they do not happen in the same way as plate tectonics, which is a process unique to Earth.
The ridges, which appear on the left side of the image, are rugged features and are elevated above surrounding terrain. The brightness patterns mean that the materials are fractured or blocky at the radar wavelength (2,17 cm, or about 1" - one inch). Along the south sides of the ridges are prominent cliffs, or scarps, present as thin, radar-dark lines trending West-to-East, and interpreted as faults.
These features are dark due to shadowing from the radar illumination, and have heights up to a few hundred meters (several hundred feet), based on preliminary estimates of slopes.
The area shown here is located in the mountainous region called Xanadu.
The ridges are similar in many ways to mountain chains seen at similar latitude but about 90° to the West, just West of Shangri-La (observed during a flyby in October 2005, and showin a Sea of Sand-like Dunes).
Both Regions have mountain chains or ridges that are oriented West-to-East and are spaced about 50 Km (or about 30 miles) apart. This indicates tectonic forces have acted in a North to South direction at Titan's Equatorial Region and have resulted in regular effects in Titan's crust, evidence that will help scientists better understand Titan's crust and interior.
Other linear features, probably related to the formation of the ridges, and circular features, perhaps eroded impact craters now filled with radar-dark (smooth) material, are also seen in the image. The largest circular feature, at bottom center, is about 20 Km in diameter.
The image is centered at 2° South Lat. and 127° West Long. and was obtained on May 12, 2008, with a resolution of about 300 meters (980 feet). The open arrow indicates the direction of radar illumination.
The dashed white line in the upper portion is an artifact of the SAR processing and will be removed in later versions".MareKromium
(5 voti)
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Titan-PIA09833-00.jpgTitan, from 213.000 Km (1 - RAW b/w; credits: NASA)55 visiteCaption NASA:"Titan's hazy orange globe hangs before the Cassini spacecraft, partly illuminated - a world with many mysteries yet to be uncovered.
North on Titan is up and rotated 30° to the right. The moon's North Pole tilts slightly away from the Spacecraft here.
This view was obtained at a distance of approx. 213.000 Km (such as about 133.000 miles) from Titan and at a Sun-Titan-Spacecraft, or phase, angle of 128°.
Image scale is roughly 13 Km (about 8 miles) per pixel".MareKromium
(5 voti)
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Titan-PIA09833-02.jpgTitan, from 213.000 Km (3 - natural colors; credits: Lunexit)82 visitenessun commentoMareKromium
(5 voti)
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