| Piú votate - Titan: The "Foggy" Moon |
00-Titan.JPGTitan in possible True Colors (credits: NASA)62 visiteAttraverso l’oculare di un (anche) modesto telescopio, Titano, il più grande satellite naturale del pianeta Saturno, appare come un corpo puntiforme che splende debolmente di un delicato color giallo-pallido.
Si tratta di un oggetto celeste reso affascinante dalla sua posizione – apparentemente assai prossima – rispetto al Gigante Anellato (la sua distanza angolare da Saturno non supera mai i 20 raggi saturniani), ma certo non si può dire che Titano, in sé, riesca a suggerire particolari interessi e curiosità visive, anzi: nessun rilievo superficiale di questo Mondo, infatti, risulta discernibile nelle osservazioni effettuate da Terra (nemmeno usando le più sofisticate ed avanzate tecniche fotografiche) e, come abbiamo appreso grazie alle immagini ottenute dalle Sonde Voyager prima e dall’Orbiter Cassini poi, anche da distanza (relativamente) ravvicinata questo mondo risulta alquanto indecifrabile (anche se occorre dire che, già dalla metà degli Anni ’70, l’effettuazione di una serie di osservazioni ripetute di Titano – effettuate usando i più grandi telescopi terrestri al tempo disponibili – aveva, peraltro correttamente, suggerito agli Astronomi una sostanziale NON uniformità, in termini di albedo, della sua superficie la quale venne ben interpretata, sin d’allora, come indice della possibile presenza di aree superficiali sensibilmente disomogenee ed equiparabili a continenti).
MareKromium
(7 voti)
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Titan-N00112025.jpgUnknown Object in the Space of Titan (additional process. and color. by Lunexit)72 visiteTutti noi sappiamo riconoscere lo "streak" lasciato su un frame dal transito di un Raggio Cosmico (ormai gli esempi sono migliaia).
In questo caso, come ben si vede nell'inset (un extra-detail mgnf), l'oggetto luminoso evidenzia una "testa", una "coda" e quindi lascia anche intuire una "scia più debole - che si diparte dalla fine della "coda" e che è caratterizzata da perdita di materiale" (o da "scorie" di un qualche tipo).
Un bolide, forse.
Molto probabilmente un O.V.N.I. e, sicuramente, NON un Raggio Cosmico.MareKromium
(7 voti)
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Titan-Regions-Adiri_Region-PIA08968.jpgAdiri Region64 visiteCaption NASA:"Peering through Titan's thick haze, the Cassini spacecraft glimpses boundaries between bright and dark terrain on the moon's Trailing Hemisphere.
The bright terrain at bottom is in North-Western Adiri.
North on Titan is up and rotated about 15 degrees 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. Some processing artifacts remain in the finished image, including the two small, dark circles below and right of center.
The images were taken with the Cassini spacecraft narrow-angle camera on May 13, 2007 at a distance of approx. 237.000 Km (about 147.000 miles) from Titan. Image scale is roughly 3 Km 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
(7 voti)
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Titan-Regions-Sinlap_Region-LS28_PSS_LASoderblom_VIMSRADAR20070323.jpgSinlap Region and Guabonito Crater56 visiteIn this composite image, Titan’s surface areas are correlated.
The top pair is composed by Cassini’s radar images, while the bottom pair shows Cassini’s VIMS images. Each of the four panels corresponds to an area about 200 Km wide.
The left views show the Sinlap Crater; the brown features in the bottom panel correspond to the large dune fields visible in the top panel.
The right views show the Guabonito Region situated at about 150 Km East of the Huygens Landing Site. MareKromium
(7 voti)
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Titan-Seas-Kraken_Mare-PIA08365.jpgTitanian Seas55 visiteCassini peers through the murky orange haze of Titan to spy what are believed to be bodies of liquid hydrocarbons, 2 of them as large as seas on Earth, near the moon's North Pole. This picture blends a near natural-color view and an infrared glimpse of Titan's surface obtained by the visual cameras, followed by a transition to imagery collected by the radar instrument aboard Cassini, for a dramatic reveal of the North Pole of Saturn's largest moon.
As the image zooms in on the North Pole, the most readily visible bodies are outlined in blue. The largest of these, on the left, is as big as the Caspian Sea on Earth; the next largest, on the right, is about the size of Lake Superior. When compared to the surface area of Titan however (which is six times smaller than Earth's), these bodies are equivalent in size to the Bay of Bengal and Timor Sea, respectively. Geographically speaking, they are more like seas.
(7 voti)
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Titan-PIA09034.jpgCloudless Titan...54 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
(7 voti)
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Titan-Lakes-Unnamed_North_Polar_Lakes-04-PIA01943.jpgTitanian Northern Lakes (4)58 visiteCaption NASA originale:"In this image taken by the Cassini radar system, a previously unseen style of lakes is revealed. The lakes here assume complex shapes and are among the darkest seen so far on Titan.
The lake at the left is reminiscent both in form and scale of the flooded drainage system, Lake Powell in Utah and Arizona. However, the Titan lake has been filled with liquid methane and ethane rather than water. In the lake at right, older terrain may have been deeply cut by river valleys before it was flooded by the embaying lake.
This radar image was acquired Oct. 9, 2006, and is centered near 80° North Latitude and 357° West Longitude. It measures about 310 by 100 Km (such as about 190 by 62 miles). Smallest details in this image are about 500 mt (approx. 1.640 feet) across".
(7 voti)
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Titan_and_Enceladus-PIA08235.jpgTitan and Enceladus54 visiteCaption NASA originale:"Saturn's Rings cut across an eerie scene that is ruled by Titan's luminous crescent and globe-encircling haze, broken by the small moon Enceladus, whose icy jets are dimly visible at its South Pole. North is up.
The scattered light around planet-sized Titan makes the moon's solid surface visible in silhouette. Enceladus enjoys far clearer skies than its giant sibling moon.
This view shows the unlit side of Saturn's Rings.
The image was taken in visible red light with the Cassini spacecraft narrow-angle camera on June 10, 2006 at a distance of approximately 3,9 MKM (about 2,4 MMs) from Enceladus and 5,3 MKM (3,3 MMs) from Titan. The view was obtained at a Sun-moon-spacecraft, or phase, angle of about 160°, relative to both moons.
Image scale is roughly 23 Km (about 15 miles) per pixel on Enceladus and roughly 32 Km (about 20 miles) on Titan".
(7 voti)
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Titan-PIA07774.jpgCrescent Titan54 visiteWith its thick, distended atmosphere, Titan's orange globe shines softly, encircled by a thin halo of purple light-scattering haze. Images taken using blue, green and red spectral filters were used to create this enhanced-color view; the color images were combined with an ultraviolet view that makes the high-altitude, detached layer of haze visible.
The ultraviolet part of the composite image was given a purplish hue to match the bluish-purple color of the upper atmospheric haze seen in visible light.
Small particles that populate high hazes in Titan's atmosphere scatter short wavelengths more efficiently than longer visible or infrared wavelengths, so the best possible observations of the detached layer are made in ultraviolet light.
The images in this view were taken by the Cassini narrow-angle camera on May 5, 2005, at a distance of approx. 1,4 MKM (about 900.000 miles) from Titan and at a phase angle of 137°.
Image scale is 8 Km (5 miles) per pixel.
(7 voti)
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Titan-Surface-33-PIA06440.jpgThe surface of Titan (again)57 visiteOriginal caption:"Images from the European Space Agency's Huygens probe descent imager/spectral radiometer side-looking imager and from the medium resolution imager, acquired after landing, were merged to produce this image.
The horizon's position implies a pitch of the imager/spectral radiometer, nose-upward, by 1 to 2° with no measurable roll. The "stones" (?) in the foreground are 4 to 6" (10 to 15 cm) in size, presumably made of water ice and these lie on a darker, finer-grained substrate.
A region with a relatively low number of rocks lies between clusters of rocks in the foreground and the background and matches the general orientation of channel-like features in the panorama of PIA06439.
The scene evokes the possibility of a dry lakebed".
(7 voti)
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Titan-Channels-Unnamed_Channels-PIA03564.jpgCanyonland on Titan54 visiteFluids have flowed and cut these deeply-incised channels into the icy surface of Titan as seen in this SAR image. The channels are roughly 1 Km across (about 0,6 miles) and perhaps 200 mt deep (about 650 feet); some can be traced as far as 200 Km (about 120 miles). Many of them have angular segments suggesting they may follow faults in Titan's crust.
Taken together with the two other radar passes (October 2004 and February 2005), these very HR images have identified at least two distinct types of drainage and channel formation on Titan. The style shown in this image consists of long valleys following angular patterns without many tributaries, suggesting that fluids flow over great distances.
This Cassini radar image was acquired as a part of the Titan flyby observations taken on Sept. 7, 2005, from a distance of about 2000 Km. The area is located at about 55° South Latitude, 7,5° West Longitude and extends over 300 km (about 186 miles) right to left.
(7 voti)
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Titan-PIA07730.jpgTitan, from about 159.000 Km54 visiteThis processed image from Cassini's Aug. 22, 2005, flyby of Titan reveals mid-latitudes on the Moon's Saturn-facing side.
Provisional names recently have been applied to a number of features on Titan. Features within the Region seen here - long known informally as the "H" - now have names like Tsegihi, Aztlan and Quivira.
The bright 215-Km-wide feature provisionally named "Bazaruto Facula" is clearly visible right of center, with its dark, unnamed 80-Km-wide crater at its center.
This view was acquired with the wide-angle camera at a distance of approx. 159.000 Km from Titan using a spectral filter centered on infrared wavelengths at 939 nnmts. The image scale is 9 Km per pixel.
Previous observations indicate that, due to Titan's thick and very hazy atmosphere, the sizes of surface features that can be resolved are a few times larger than the actual pixel scale.
(7 voti)
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