| Piú votate - Titan: The "Foggy" Moon |
Titan-PIA06122_modest.jpgTitan from about 1.000.000 Km (true colors)53 visiteUn'immagine davvero molto ben definita in cui si può distinguere nettamente, nonostante la distanza della Sonda dal Pianeta sia ancora considerevole, la particolare tessitura (oltre al colore davvero curioso - grigio/viola?) degli strati alti dell'atmosfera di Titano.
(11 voti)
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Titan-Atmosphere_and_Haze-00.jpgTitan from approx. 789.000 Km (The "Double Purple Haze")59 visitenessun commento
(11 voti)
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Titan-Clouds-PIA09033.jpgClouds and Surface54 visiteCaption NASA originale:"This image set was taken at a distance of 15.000 Km (9.300 miles) from Titan and shows two views of an area riddled by mountain ranges that were probably produced by tectonic forces.
Near the bottom of the right image, a band of bright clouds is seen.
These clouds are probably produced when gaseous methane in Titan's atmosphere cools and condenses into methane fog as Titan's winds drive air over the mountains. It was once thought that these recurring clouds were produced by volcanic activity on Titan, but this image calls that idea into question.
These views were obtained during an Oct. 25 flyby designed to obtain the highest-resolution infrared views of Titan yet. Cassini's VIMS resolved surface features as small as 400 mt (1300 feet). 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
(10 voti)
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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".
(10 voti)
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Titan-Clouds-PIA06157.jpgTitan: Mid-Latitude Clouds54 visiteCaption NASA originale:"The Clouds seen here are at about 38° South Latitude on Titan. The Clouds across the middle of the frame extend about 250 Km (approx. 155 miles). The image scale is about 0,6 Km (approx. 0,4 miles) per pixel".
(10 voti)
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Titan-PIA06983_modest.jpgTitan (false colors) + the Huygens' probe landing site55 visiteCaption NASA originale:"This image taken by Cassini's visual and infrared mapping spectrometer clearly shows surface features on Titan. It is a composite of false-color images taken at three infrared wavelengths: 2 microns (blue); 2.7 microns (red); and 5 microns (green). A methane cloud can be seen at the south pole (top of image). This picture was obtained as Cassini flew by Titan at altitudes ranging from 100.000 to 140.000 Km (88.000 to 63.000 miles), less than two hours before the spacecraft's closest approach. The inset picture shows the landing site of Cassini's piggybacked Huygens probe".
(10 voti)
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Titan-Surface-20.gifThe "Polygonal" Surface of Titan (GIF-Movie; credits: Dr A. Feltri)123 visitePurtroppo (ed ormai da tempo) il Dr Feltri ha smesso di scrivere sulle pagine di Lunar Explorer Italia e quindi, per illustrare in modo adeguato questo (straordinario) GIF-Movie, dovremmo provare ad interpretare le sue missive e quindi riassumere il suo pensiero: un'opera improba, ahinoi!...
Comunque sia, osservate attentamente questo montaggio di immagini rappresentative del suolo presente al di sotto della Sonda Huygens: che cosa notate in particolare? Il dettaglio è talmente evidente che non dovremmo neppure esplicitarlo ma...lo facciamo lo stesso: la texture della superficie di Titano è rappresentata da una sorta di maglia reticolare, in cui ogni reticolo ha una forma perfettamente esagonale (ATTENZIONE: potrebbe anche trattarsi di una banalissima maglia metallica di protezione del vano in cui è posizionata la fotocamera, ma non abbiamo elementi a supporto di una tale, pur logica, ipotesi).
I movimenti ed i cambi di albedo che vedete nel filmato potrebbero indicare una regolare "pulsazione" del suolo (se vogliamo essere ultra-esotici), oppure potrebbero essere indici del passaggio, su di esso, di una leggera corrente d'aria e/o di un fluido.
Il greto del torrente su cui Huygens è discesa è - forse - solo parzialmente asciutto? Probabilmente si. Probabilmente, al di sotto della Sonda, ancora scorre qualcosa. Qualcosa che riflette ed amplifica - sia pure debolmente - le luci del paesaggio circostante.
Ma l'elemento essenziale del filmato, lo ripetiamo, è nella texture del suolo (ammettendo che non sia l'evidenza di una griglia di protezione della fotocamera): una specie di struttura ad alveare, costituita da un materiale che ci appare (evidentemente) traslucido e che - forse - ha una matrice cristallina (se non altro in parte).
La teorizzazione del Dr Feltri è troppo articolata e complessa per essere riassunta in una caption di questo tipo e quindi ci fermiamo qui, invitando il nostro Amico Alessio a scrivere qualcosa al riguardo, se vuole.
Qualcosa che, se scritta, verrà certamente pubblicata nella seconda parte di "Oltre la Nebbia": la nostra (piccola) monografia su Titano, di prossima uscita su TruePlanets.
E se invece il bravissimo Dr Feltri non scriverà nulla, allora proveremo noi a dire qualcosa su questa "evidenza visiva" relativa all'esistenza di un qualche tipo di processo (biochimico? Biomagnetico? O forse un Tertium Genus?!?) il quale, attualmente in corso sulla Luna Nebbiosa, è talmente straordinario da meritare TUTTA LA NOSTRA ATTENZIONE!
Ed ora, se volete, attendiamo i Vostri commenti...MareKromium
(9 voti)
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Titan-Regions-Shangri_La_Region-PIA08971.jpgShangri-la and other Equatorial Regions of Titan56 visiteCaption NASA:"This view of Titan's surface highlights NorthWestern Shangri-la - a large, Equatorial Dark Region revealed by radar observations to be covered in longitudinal dune fields. The bright, circular feature right of center is a potential impact crater - few of which have been spotted on Titan thus far.
North on Titan is up and rotated about 15° to the right. This view was created by combining multiple images taken using a combination of spectral filters sensitive to wavelengths of infrared light centered at 938 and 619 nanometers.
The images were taken with the Cassini spacecraft narrow-angle camera on May 13, 2007 at a distance of approx. 125.000 Km (about 77.000 miles) from Titan. Image scale is roughly 1 Km (0,6 miles) per pixel. Due to scattering of light by Titan's hazy atmosphere, the sizes of surface features that can be resolved are a few times larger than the actual pixel scale".MareKromium
(9 voti)
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Titan-Lakes-Unnamed_North_Polar_Lakes-06-PIA08740.jpgTitanian Northern Lakes (6)64 visiteCaption NASA originale:"This Cassini radar image shows two lakes "kissing" each other on the surface of Saturn's moon Titan.
The image has been taken from a fly-by occurred on Sept. 23, 2006, and covers an area of about 60 Km (approx. 37 miles) wide by 40 Km (approx. 25 miles) high.
This pass was primarily dedicated to the ion and neutral mass spectrometer instrument, so although, the volume of radar data was small, scientists were amazed to see Earth-like lakes. With Titan's colder temperatures and hydrocarbon-rich atmosphere, however, the lakes likely contain a combination of methane and ethane, not water.
In this image, near 73° North Latitude and 46° West Longitude, two lakes are seen, each 20 to 25 Km (approx. 12 to 16 miles) across. They are joined by a relatively narrow channel. The lake on the right has lighter patches within it, indicating that it may be slowly drying out as the Northern Summer approaches".
(9 voti)
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Titan-PIA06997_modest.jpgHaze Silhouettes Against Titan's Glow54 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".
(9 voti)
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Titan-Crescent-01.jpgTitan from approx. 790.000 Km54 visitenessun commento
(9 voti)
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Titan-Regions-Fensal_and_Senkyo_Regions-PIA12655-PCF-LXTT.jpgAztlan, Fensal and Senkyo Region (Absolute Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)55 visiteCaption NASA:"The Cassini Spacecraft looks toward the dark Senkyo Region on Saturn's moon Titan.
Senkyo is the Dark Region towards the right. Two other Dark Regions, Aztlan (to the left, slanting down below the Equator) and Fensal (left, North of Aztlan), are also shown here.
The bright area below Aztlan is called Tsegihi. This view looks toward the Saturn-facing Side of Titan. North on Titan is up and rotated 9° to the left.
The image was taken with the Cassini Spacecraft narrow-angle camera on April 8, 2010 using a spectral filter sensitive to wavelengths of Near-InfraRed Light centered at 938 nanometers. The view was obtained at a distance of approx. 2,1 MKM (about 1,3 MMs) from Titan and at a Sun-Titan-Spacecraft, or Phase, Angle of 33°.
Image scale is roughly 12 Km (a little more than 7 miles) per pixel".MareKromium
(8 voti)
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