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Titan-Clouds-PIA06159.jpgTitanian Clouds (December 2004 fly-by)54 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. This mosaic includes some areas seen at regional scales in October 2004 (see PIA 06124), as well as additional areas to the north and east not seen during that flyby. Among the new features seen in this mosaic is a strangely shaped bright feature near the center of the image as well as clouds near the bottom of the image (see also PIA 06110). The northern portion of the bright/dark boundary appears to be more complex than the arching and sharp boundary seen farther to the south. Cassini scientists continue to examine images such as this to determine the cause of this terrain. The images in this mosaic have been processed to enhance surface features and sharpen brightness variations".
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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
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Titan-Clouds-PIA09036.jpgTitanian Clouds and Surface54 visiteCaption NASA originale:"This image composite contains a radar image taken during a February 2005 (T3) flyby, and overlaid are images from the Visual and Infrared Mapping Spectrometer (VIMS) taken on Sept. 7, 2006, (T17) and Oct. 25, 2006 (T20).
The thin strip is the infrared image taken on the inbound leg of the T20 flyby and crosses the radar image near an area with a small, crater-like feature. In the radar image a faint fan of material seems to originate at the crater and the portion of the infrared image that crosses the faint fan shows both a large brightness contrast and very sharp boundaries. The fan-like deposit has such sharp boundaries and strong contrast with its surroundings that it supports the idea that the deposit seen in the radar images is a flow of material erupted from the small crater. This may be the strongest evidence yet of cryovolcanism on Titan.
The infrared image was taken at a distance of about 1100 Km (680 miles) from the surface of Titan and resolves features as small as 400 mt (1300 feet)".MareKromium
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Titan-Clouds-PIA12813.jpgTitanian Clouds60 visiteMareKromium
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Titan-Clouds-PIA13400-PCF-LXTT.jpgTitanian Clouds (Absolute Natural Colors; credits for the additional process. and color.: NASA/JPL/University of Arizona/University of Nantes/University of Paris Diderot and Dr Paolo C. Fienga - Lunexit Team)124 visitenessun commentoMareKromium
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Titan-Clouds-PIA13400.jpgTitanian Clouds (False Colors; credits: NASA/JPL/University of Arizona/University of Nantes/University of Paris Diderot)92 visiteCaption NASA:"This pair of false-color images, made from data obtained by NASA's Cassini Spacecraft, shows clouds covering parts of Saturn's moon Titan in yellow. Based on the way Near-InfraRed channels of light were color-coded, cloud cover appears yellow, while Titan's hazy Atmosphere appears magenta. The images show cloud cover dissolving from Titan's North Polar Region between May 12, 2008 (left), and Dec. 12, 2009 (right). The clouds in the second image appear around 40° South Latitude, still active late after Titan's Equinox.
Cassini's first observations of clouds near this Latitude occurred during Summer in the Southern Hemisphere. Equinox, when the Sun shone directly over the Equator, occurred in August 2009. It brought a changing of the seasons, as Titan moved out of Southern Summer into Northern Spring.
For the past 6 years, Cassini has observed clouds clustered in three distinct Latitude Regions of Titan: large clouds at the North Pole, patchy cloud at the South Pole and a narrow belt around 40° South. Now scientists are seeing evidence of seasonal circulation turnover at Titan. Clouds at the South Pole disappeared just before Equinox and the clouds in the North are thinning out. This activity agrees with models that predict cloud activity reversing from one Hemisphere to another.
During Winter in the Northern Hemisphere, Northern Polar Clouds of Ethane formed in Titan's Troposphere, the lowest part of the Atmosphere, from a constant influx of Ethane and Aerosols from a higher part of the Atmosphere known as the Stratosphere.
In the Southern Hemisphere, atmospheric gases enriched with Methane welled up from the Surface to produce Mid and High-Latitude Clouds.
The data for the images was detected by Cassini's Visual and InfraRed Mapping Spectrometer in Near-IR wavelengths. Scientists focused on three wavelengths of IR radiation that were particularly good for observing cloud signatures and assigned them red, green and blue channels.
Emissions in the 2 micron wavelength of light, colored red, detect the Titan Surface.
Emissions in the 2,11 micron wavelength, colored green, detect the lowest part of the Titan Atmosphere, or Troposphere.
Emissions at the 2,21 micron wavelength, colored blue, detect the hazy Stratosphere, a higher part of the Atmosphere.
The clouds appear yellowish because they lit up the channels designated red and green, but not the blue channel".MareKromium
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Titan-Clouds-Rain_Clouds-PIA12818-00.jpgTitanian "Deluge"105 visitenessun commentoMareKromium
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Titan-Clouds-Rain_Clouds-PIA12818-01.jpgTitanian "Deluge"137 visiteCaption NASA:"This series of images from NASA's Cassini Spacecraft shows changes on the Surface of Saturn's moon Titan, as the transition to Northern Spring brings Methane Rains to the moon's Equatorial Latitudes. Some of the most significant changes appear within a period of only a couple of weeks.
The brightest objects seen in these images are Methane Clouds in the Troposphere, such as the lowest part of the Atmosphere, which are most visible on the left of panel B, the lower half of panel C, and the right of panel D.
Surface features appear in shades of gray.
These images show changes (outlined area) along the Southern Boundary of a Dunefield near the Equator named Belet. Dark Belet occupies most of the top of these images (Belet looks dark because it is made from different materials than neighboring areas).
Titan's Equatorial Latitudes are mostly arid. However, scientists interpret the changes seen in these images to be evidence of Methane Rain wetting the Surface. Scientists have monitored the brightness of Titan's Surface, including this area, for years and have ruled out other possible causes of the changes. In these images, some of the dark areas grow larger and then recede within weeks. The maximum extent of the changes is shown with a blue outline.
Years ago, images from the European Space Agency's Huygens probe and the Cassini radar instrument revealed Dry Channels near the Equator. The new observations suggest the climate here is similar to that in the South-Western part of the United States, where infrequent Rain carves washes and riverbeds.
Titan's weather has been changing with the Seasons, and Storms now are more common at low Latitudes, such as those observed here. An arrow-shaped Storm cloud several hundred kilometers across was observed on Sept. 27, 2010.
The first image in this montage, panel A on the left, was taken early in the Cassini Mission on Oct. 22, 2007, and shows how this Region had appeared before the Storms.
The second image, panel B, was taken on Sept. 27, 2010. The huge arrow-shaped Cloud is just out-of-frame to the left in panel B.
The arrow-shaped cloud was quickly followed by extensive changes on the Surface that can be seen in panel C, an image captured on Oct. 14, 2010. These changes cover an area of approx. 500.000 square Km (310.500 square miles), roughly the combined area of Arizona and Utah in the United States.
The wet Terrain can still be seen about a month after the storm in panel D, which was taken on Oct. 29, 2010.
But by Jan. 15, 2011, which was the date of panel E, the area mostly appears dry and bright, with a much smaller area still dark (such as wet).
These images were re-projected, and the view in each is centered on Terrain at 19° South Latitude and 251° West Longitude.
Images in panels A, B, D, and E were taken with the Cassini Spacecraft narrow-angle camera using a spectral filter sensitive to wavelengths of Near-InfraRed Light centered at 938 nanometers.
The image in panel C was taken with the Cassini wide-angle camera using the same filter. The views were obtained at a range of distances from approx. 211.000 Km (131.031 miles) to about 1,85 MKM (such as 1.148.850 miles) from Titan.
Scale is about 7 Km (4,3469 miles) per pixel in these re-projected images".MareKromium
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Titan-Clouds-Rain_Clouds-PIA12819.jpgThe "Rain Season" on Titan160 visiteCaption NASA:"Images from NASA's Cassini Spacecraft show changes caused by Methane Rain in the bright Adiri Region near the Equator of Saturn's largest moon, Titan.
Although no Clouds are present in these images, the changes wrought by recent Methane Rainstorms are visible. These images show areas of brightened Terrain within the already bright Region known as Adiri. Adiri's Terrain appears near the center of these frames.
The dark, low-lying Dunefield known as Belet extends West from the left of these frames. Terrain South of Belet was soaked by Methane Rains in late 2010 (Adiri and Belet have different brightnesses because they - most likely - have different compositions).
The first image, panel A on the left, was taken on May 13, 2007, and shows what this area looked like earlier in the Cassini Mission.
Panels B and C were both captured on Jan. 15, 2011, 15 hours apart. New bright areas (within the white outlines of panels B and C) are thought to be on or near the Surface of the Planet.
These bright objects are not high altitude Clouds because they do not drift during the 15 hours between when panel B and panel C were taken.
Scientists are still analyzing the findings, but these brightened spots could be low-lying Fog or Clouds in areas with higher amounts of moisture on the Surface.
They could also possibly be Terrain that has been washed clean by Methane Rains (the bright spots did not become brighter in the 15 hours between panels B and C. They appear brighter only because of a change in the so-called "Viewing Geometry").
Titan's weather has been changing with the Seasons, and Storms now are more common at low Latitudes such as those observed here.
These images were re-projected, and the view in each is centered on terrain at 7° South Latitude and 215° West Longitude.
These images were taken with the Cassini Spacecraft narrow-angle camera using a spectral filter sensitive to wavelengths of Near-InfraRed Light centered at 938 nanometers. The views were obtained at a range of distances from approx. 150.000 Km (93.150 miles) to approx. 997.000 Km (619.137 miles) from Titan.
Scale is about 7 Km (4,3469 miles) per pixel in these re-projected images".MareKromium
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Titan-Clouds-South_Polar_White_Clouds-PIA06510_modest.jpgWhite Clouds near the South Pole of Titan54 visiteThis image shows Titan, Saturn's largest moon (5.150 Km - 3.200 miles - across), with a streak-like cloud near its South Pole. The cloud may be part of a region of polar clouds seen during Cassini’s first flyby of Titan in July 2004, only now covering a larger area.
Titan's atmosphere, like that of Earth, is mostly nitrogen. The pressure at Titan’s surface is 50% higher than on Earth, despite its lower gravity, meaning that the mass of the atmosphere per unit area is more than 10 times that on Earth.
The image was taken in visible light with the Cassini spacecraft narrow angle camera on Sept. 23, 2004, at a distance of 7.1 MKMs (4.4 million miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 84°.
The image scale is 42 Km (26 miles) per pixel.
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Titan-Clouds-Water_Ice_Clouds-MF-LXTT.jpgWater-ice Clouds' Complex on Titan (an Image-Mosaic by Dr Marco Faccin - Lunexit Team)95 visitenessun commentoMareKromium
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Titan-Clouds-White_Clouds-Mosaic.jpgTitan from about 340.000 Km57 visiteCaption originale da "NASA - Picture of the Day" del 26 Ottobre 2004:"What are these surface features on Titan? This planet-sized moon of Saturn had much of its south polar surface imaged during an initial flyby by the Saturn-orbiting Cassini spacecraft back in early July. The above image mosaic was digitally stitched together from pictures taken at a very specific color of polarized infrared light, a color not absorbed and little scattered by Titan's methane haze. Visible are light and dark regions that are not yet understood. Surface features as small as 10 Km are resolved from about 340.000 Km away. The white region near Titan's South Pole, left of center, is unusually thick clouds also thought to be composed of methane. Today Cassini will swoop to within 1,500 kilometers above Titan and may return data and images that help humanity better understand this strange world".
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