| 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-PIA06983_modest.jpgTitan (false colors) + the Huygens' probe landing site54 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-Atmosphere_and_Haze-00.jpgTitan from approx. 789.000 Km (The "Double Purple Haze")58 visitenessun commento
(10 voti)
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Titan-Clouds-PIA09033.jpgClouds and Surface53 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
(9 voti)
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Titan-Lakes-Unnamed_North_Polar_Lakes-06-PIA08740.jpgTitanian Northern Lakes (6)63 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-Atmosphere-PIA06236.jpgThe Atmosphere of Titan54 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".
(9 voti)
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Titan-Clouds-PIA06157.jpgTitan: Mid-Latitude Clouds53 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".
(9 voti)
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Titan-Crescent-01.jpgTitan from approx. 790.000 Km53 visitenessun commento
(9 voti)
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Titan_and_Dione-EB-LXTT-1.jpgFading in the Background... (Natural Colors; credits: Elisabetta Bonora - Lunexit Team)54 visitenessun commentoMareKromium
(8 voti)
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Titan-Lakes-Unnamed_North_Polar_Lake-PIA12481.jpgReflection of Sunlight off a Titanian Northern Lake (Natural Colors; credits: NASA/JPL/University of Arizona/DLR)171 visiteThis image shows the first flash of sunlight reflected off a lake on Saturn's moon Titan. The glint off a mirror-like surface is known as a specular reflection. This kind of glint was detected by the visual and infrared mapping spectrometer (VIMS) on NASA's Cassini spacecraft on July 8, 2009. It confirmed the presence of liquid in the moon's northern hemisphere, where lakes are more numerous and larger than those in the southern hemisphere. Scientists using VIMS had confirmed the presence of liquid in Ontario Lacus, the largest lake in the southern hemisphere, in 2008.
The northern hemisphere was shrouded in darkness for nearly 15 years, but the sun began to illuminate the area again as it approached its spring equinox in August 2009. VIMS was able to detect the glint as the viewing geometry changed. Titan's hazy atmosphere also scatters and absorbs many wavelengths of light, including most of the visible light spectrum. But the VIMS instrument enabled scientists to look for the glint in infrared wavelengths that were able to penetrate through the moon's atmosphere. This image was created using wavelengths of light in the 5 micron range.
By comparing the new image to radar and near-infrared light images acquired from 2006 to 2008, Cassini scientists were able to correlate the reflection to the southern shoreline of a Titan lake called Kraken Mare. The sprawling Kraken Mare covers about 400,000 square kilometers (150,000 square miles). The reflection appeared to come from a part of the lake around 71 degrees north latitude and 337 degrees west latitude.
It was taken on Cassini's 59th flyby of Titan on July 8, 2009, at a distance of about 200,000 kilometers (120,000 miles). The image resolution was about 100 kilometers (60 miles) per pixel. Image processing was done at the German Aerospace Center in Berlin and the University of Arizona in Tucson.
MareKromium
(8 voti)
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Titan-Lakes-Unnamed_North_Polar_Lakes-05-PIA08741.jpgTitanian Northern Lakes (5)87 visiteCaption NASA originale:"This lake is part of a larger image taken by the Cassini radar instrument during a flyby of Saturn's moon Titan on Sept. 23, 2006.
It shows clear shorelines that are reminiscent of terrestrial lakes. With Titan's colder temperatures and hydrocarbon-rich atmosphere, however, the lake likely contain a combination of methane and ethane, not water.
Centered near 74° North Latitude and 65° West Longitude, this lake is roughly 20 by 25 Km (about 12 to 16 miles) across. It features several narrow or angular bays, including a broad peninsula that on Earth would be evidence that the surrounding terrain is higher and confines the liquid. Broader bays, such as the one seen at right, might result when the terrain is gentler, as for example on a beach".
(8 voti)
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Titan-Map-PIA02147.jpgGlobal Titan Map (Visual + IMS)55 visiteThis global infrared map of Titan was composed with data from Cassini's visual and infrared mapping spectrometer taken during the last two Titan flybys, on Dec. 26, 2005, and Jan. 15, 2006.
There are several important features to note in this Map:
1) the globe of Titan exhibits 2 major types of terrain: one is very bright, and a darker one seems to be concentrated near the Equator;
2) Titan has two very bright Regions: the large one known as Tui Reggio, located at approx. 25° South Lat. and 130° West Long., and the other as Hotei Arcus, at 20° South Lat. and 80° West Long. These regions are thought to be surface deposits, probably of volcanic origin, and may be water and/or carbon dioxide frozen from the volcanic vapor; the western margins of Tui Reggio have a complex flow-like structure consistent with eruptive phenomena;
3) the reddish feature at the South Pole is Titan's South Polar cloud system, which was very bright during the December flyby;
4) The Sinlap Crater is clearly visible at approx. 13° North Lat. and 16° West Long. The poorly resolved Regions between Longitudes of 30° and 150° East will be filled in during subsequent flybys.
(8 voti)
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