| Piú viste - Titan: The "Foggy" Moon |
Titan-Clouds-PIA06158.jpgTitanian Clouds (October 2004 fly-by)59 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".
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Titan-Huygens_Landing_Site-10-PIA06173_modest.jpgHuygens' descent map (2)59 visiteCaption NASA originale:"For about two hours, the probe will fall by parachute from an altitude of 160 Km (99 miles) to Titan's surface. During the descent the DISR and a few other science instruments will send data about the moon's atmosphere and surface back to the Cassini spacecraft for relay to Earth. The DISR will take pictures as the probe slowly spins and some of these will be made into panoramic views of Titan's surface.
The first map (PIA-06172) shows expected coverage by the Descent Imager/Spectral Radiometer side-looking imager and two downward-looking imagers - one providing medium-resolution and the other high-resolution coverage. The planned coverage by the medium- and high-resolution imagers is the subject of this map (PIA-06173)".
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Titan-Surface-30.jpgOn the surface of Titan59 visiteCaption ESA originale:"This raw image was returned by the ESA Huygens DISR camera after the probe descended through the atmosphere of Titan. It shows the surface of Titan with ice blocks strewn around. The size and distance of the blocks will be determined when the image is properly processed". Dunque Huygens ce l'ha fatta: è scesa su Titano! E la qualità di queste prime immagini supera le nostre più rosee aspettative: la visibilità è buona e questa parte di Titano sembra ricordarci - vagamente - la superficie di Venere, così come ripresa dalle Sonde Sovietiche "Venera".
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Titan-Shoreline_and_Drainage_Channels-00.jpgShoreline and Drainage Channels' Network on Titan 59 visiteCaption ESA originale:"This is one of the first raw images returned by the ESA Huygens probe during its successful descent. It was taken from an altitude of 16,2 Km with a resolution of approximately 40 metres per pixel. It apparently shows short, stubby drainage channels leading to a shoreline".
Il profilo di un tratto costiero, dunque: montagne (o colline), una fitta rete di canali ed una porzione di "mare" alla vista. Mare.
Già, ma un mare fatto di cosa?...
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Titan-Shoreline_and_Drainage_Channels-02a.jpgShoreline and Drainage Channels59 visiteUn'altra istantanea di Titano ripresa durante la quieta discesa di Huygens verso la superficie di questo mondo ritenuto dagli Scienziati e dai Ricercatori di tutto il Mondo come una "versione gelida" (temperatura media di superficie: circa -180°C) di quello che era la Terra ai suoi albori.
L'atmosfera di Titano è prevalentemente costituita da azoto, con l'aggiunta di metano ed altri elementi di natura organica.
Si noti che alcuni di questi "organic compounds", se riscontrati nell'atmosfera di un corpo celeste simile alla Terra, sarebbero indici forti dell'esistenza di forma di vita indigene. Sulla Terra, infatti, la formazione del metano è legata all'esistenza di forme di vita nel senso che il metano stesso è un sottoprodotto ("by-product") del metabolismo di svariati organismi. E' la Vita stessa, insomma, che sulla Terra contribuisce a ricostituire continuamente le scorte di metano, sostituendo quello andato distrutto per ossidazione. Ma su Titano? Da dove viene tutto il metano che abbiamo scoperto?
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Titan-Huygens_Landing_Site-06.jpgThe "Landing Site": a new best estimate59 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)".
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Titan-PIA06220.jpgA New Continent on Titan (from 130.000 up to 146.000 Km)59 visiteCaption NASA originale:"This view of Titan uncovers new territory not previously seen at this resolution by Cassini's cameras. The view is a composite of 4 nearly identical wide-angle camera images, all taken using a filter sensitive to wavelengths of infrared light centered at 939 nnmts. The individual images have been combined and contrast-enhanced in such a way as to sharpen surface features and enhance overall brightness variations. Some of the territory in this view was covered by observations made by the Cassini synthetic aperture radar in October 2004 and February 2005. At large scales, there are similarities between the views taken by the imaging science subsystem cameras and the radar results, but there also are differences. For example, the center of the floor of the approximately 80-kilometer-wide (50-mile) crater identified by the radar team in February (near the center in this image, see PIA07368 for the radar image) is relatively bright at 2.2 centimeters, the wavelength of the radar experiment, but dark in the near-infrared wavelengths used here by Cassini's optical cameras. This brightness difference is also apparent for some of the surrounding material and could indicate differences in surface composition or roughness".
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Titan-2-PIA06230.jpgTitan in three different wavelenghts: the natural Titan (2)59 visiteCaption NASA originale:"This natural color composite was taken during the Cassini spacecraft's April 16, 2005, flyby of Titan. It is a combination of images taken through three filters that are sensitive to red, green and violet light.
It shows approximately what Titan would look like to the human eye: a hazy orange globe surrounded by a tenuous, bluish haze. The orange color is due to the hydrocarbon particles which make up Titan's atmospheric haze. This obscuring haze was particularly frustrating for planetary scientists following the NASA Voyager 1 and 2 mission encounters in 1980-81. Fortunately, Cassini is able to pierce Titan's veil at infrared wavelengths (see also PIA06228). North on Titan is up and tilted 30° to the right".
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Titan-Atmosphere-IMG001498-br500.jpgComplex Hydrocarbons in Titan's upper atmosphere59 visiteCaption NASA originale:"During its closest flyby of Saturn's moon Titan on April 16, the Cassini spacecraft came within 1.025 Km of the moon's surface and found that the outer layer of the thick, hazy atmosphere is brimming with complex hydrocarbons.
This figure shows a mass spectrum of Titan's ionosphere near 1.200 Km above its surface. The mass range covered goes from Hydrogen at 1 atomic mass unit per elementary charge (Dalton) to 99 Daltons. This mass range includes compounds with 1, 2, 3, 4, 5, 6 and 7 carbons as the base structure (as indicated in the figure label). The identified compounds include multiple carbon molecules and carbon-nitrogen bearing species as well".
Un'atmosfera "primordiale", dunque, ma teoricamente idonea per lo sviluppo di forme di vita 'prossime' (in termini di fondamenta chimiche e chimico/fisiche) alle nostre concezioni di 'forme vitali'.
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Titan-PIA07876.jpgA bright Red Spot on Titan (1)59 visiteThe recently discovered infrared-bright spot on Titan is the type of enigmatic feature that is best investigated by putting together as many different types of complementary information as possible. This montage shows the spot in infrared wavelengths from the visual and infrared mapping spectrometer on the left, from the imaging science subsystem in the center and a combination of both data sets on the right. When put together, the 2 different views show more than either does separately. The visual and infrared spectrometer team noted the bright region in the image on the left after March 31, 2004, Cassini's-Titan encounter. The strange, bright feature to the southeast of Xanadu was flagged as unusual and informally dubbed "The Smile" by imaging team members in December 2004. It seems clear that both instruments are detecting the same basic feature on Titan's surface. This bright patch may be due to an impact event, landslide, cryovolcanism, or atmospheric processes. Its distinct color and brightness suggest that it may have formed relatively recently".
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Titan-Volcano-01-PIA07961.jpgThe Titanian Volcano (2)59 visiteCaption NASA originale:"Details of the circular feature, that scientists think is an ice volcano, which could be a source of methane in Titan's atmosphere, show up at wvlgts larger than 1,3 microns (1 micron is one-millionth of a meter; 1 meter is 39"). The first 6 panels are images of the feature taken in 6 infrared windows. Images made up of two colors (ratio images) are represented in order to visualize compositional variations, which appear to be slight. The last panel is a color composite image (red, 2,75 micron; green, 2 micron; blue, 1,6 micron). These images were acquired with Cassini's VIMS. Titan, Saturn's largest moon, is the only known moon to have a significant atmosphere, composed primarily of Nitrogen, with CH4 (about 2/3%) as the largest remaining component. One goal of the Cassini mission is to find an explanation for what is replenishing and maintaining this atmosphere".
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Titan-Volcano-03-PIA07962.jpgThe Titanian Volcano (4)59 visiteCaption NASA originale:"This HR infrared image was (...) obtained by Cassini's VIMS and shows a bright, circular feature (8,5° Lat.; -143,5° Long.) with two elongated wings extending westwards".
Dunque: anche se i commenti NASA sono veramente 'minimalisti' (ai limiti del ridicolo), sembra ormai chiaro che su Titano esiste una 'fornace attiva' di un qualche tipo. Al di là delle riflessioni che già si potrebbero avviare sulla incompletezza della nostra Scienza e sulle conseguenti stupidaggini dette e scritte in passato a proposito di questo Pianeta, possiamo dire che siamo davanti, in ogni caso, ad un'evidenza incontestabile del fatto che Titano è un mondo 'geologicamente vivo e vegeto'. Vi sembra questa una notizia da poco?
Adesso, a nostro parere, tutti noi (Ricercatori e Scienziati) abbiamo una buona base fattuale per fare autocritica ed iniziare a rivedere le nostre cognizioni in materia di Scienze Planetarie e Dinamiche Evolutive dei corpi celesti ma...avremo l'umiltà per farlo?!?
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