| Ultimi arrivi - Titan: The "Foggy" Moon |
Titan-Lakes-Unnamed_North_Polar_Lakes-05-PIA08741.jpgTitanian Northern Lakes (5)91 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".Set 27, 2006
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Titan-Lakes-Unnamed_North_Polar_Lakes-06-PIA08740.jpgTitanian Northern Lakes (6)68 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".Set 27, 2006
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Titan-PIA08733.jpgCrescent Titan (HR)71 visiteCaption NASA originale:"This composite image, composed of two images taken with Cassini's Visual and Infrared Mapping Spectrometer (VIMS), shows a crescent view of Saturn's moon Titan.
The data were obtained during a flyby on July 22, 2006, at a distance of 15.700 Km (about 9.700 miles) from Titan. The image was constructed from images taken at wavelengths of 1,26 microns (blue), 2 microns (green) and 5 microns (red)".Set 14, 2006
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Titan-Clouds-White_Clouds-PIA08736.jpgThe "White Clouds" of Titan59 visiteCaption NASA originale:"This image depicts Saturn's moon Titan as seen by the Visual and Infrared Mapping Spectrometer (VIMS) after the closest approach of July 22, 2006 (fly-by n. 16).
The image was generated using the 5 micron wavelength for red, the 2 micron wavelength for green and the 1,2 micron wavelength for blue. The clouds are of the same type seen previously and reported in the journal "Science".
The image shows the clouds spreading out along the 40° South Latitude line.
This image was taken from a distance of about 160.000 Km (roughly 99.000 miles) from Titan".Set 14, 2006
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Titan-Dunes-PIA08738.jpgLongitudinal Dunes?56 visiteCaption NASA originale:"This image from Cassini's radar instrument was acquired by the Cassini radar instrument in synthetic aperture mode during a Sept. 7, 2006, flyby of Titan. The image shows long, dark ridges similar to those seen in previous flybys. These are interpreted to be "Longitudinal Dunes". Dunes are mostly an equatorial phenomenon on Titan and the material forming them may be solid organic particles or ice coated with organic material. Spaced up to 3 Km(about 2 miles) apart, these dunes curve around bright features that may be high-standing topographic obstacles, in conformity with the wind patterns.
The interaction between the 2 types of features is complex and not well understood, but clearly the topography and the dunes have influenced each other in other ways as well.
This image is centered at 44° West Long., 8° North Lat. and covers approx. 160 by 325 Km (such as about 99 by 202 miles) on Titan's surface. The smallest details in this image are about 500 mt (approx. 550 yards) across".Set 13, 2006
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Titan-Craters-Unnamed_Crater-PIA08737.jpgTitanian Crater59 visiteCaption NASA originale:"This image from Cassini's radar instrument shows an impact crater with a diameter of about 30 Km (19 miles) on the surface of Saturn's moon Titan. Cassini data have only revealed 3 definite impact craters on Titan so far, so each new discovery adds significantly to our body of knowledge. Impact craters are particularly important, as their shapes give scientists insight into the structure of the crust beneath Titan's surface. The difference in overall appearance between this crater, which has a central peak, and those without, such as Sinlap, indicates variations in the conditions of impact, thickness of the crust, or properties of the meteorite that made the crater. The dark floor indicates smooth or highly absorbing materials.
This image was acquired by the Cassini radar instrument in synthetic aperture mode during a Sept. 7, 2006, flyby of Titan.
This image is centered at 70° West Long.; 10° North Lat. and measures about 145 Km high by 180 Km wide (such as approx. 93 by 118 miles). The smallest details in this image are about 500 mt (approx. 550 yards) across".Set 13, 2006
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Titan-PIA08246.jpgTitan55 visiteCaption NASA:"This remarkably clear view from that flyby shows the moon's characteristically dark Mid-Latitudes, and more Southern Terrain than the Cassini spacecraft has usually been able to glimpse. This was the first in a series of "illuminated outbound flybys" of Titan where the illuminated Hemisphere was visible following the closest approach. Cassini's flyby of Titan on July 22, 2006 sent the spacecraft into a more inclined orbit about Saturn.
The image was taken in polarized infrared light with the Cassini spacecraft wide-angle camera on July 22, 2006 at a distance of approx. 148.000 Km (about 92.000 miles) from Titan.
Image scale is roughly 9 Km (about 5 miles) per pixel".Ago 19, 2006
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Titan_and_Enceladus-PIA08235.jpgTitan and Enceladus55 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".Ago 03, 2006
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Titan-Regions-Senkyo_and_Aaru_Regions-PIA08231.jpgAaru and Senkyo85 visiteAs it approached Titan for yet another revealing encounter, the Cassini spacecraft acquired this image showing terrain on the moon's Saturn-facing hemisphere.
Prominent dark areas found in the moon's equatorial region appear to contain vast and continuous dune fields, discovered by the Cassini Radar experiment and likely composed of particles that drop from Titan's unique, smoggy atmosphere.
The Dark Regions seen here are provisionally named Aaru and Senkyo, with parts of Western Fensal and Aztlan showing at left, near the terminator.
The image was taken with the Cassini spacecraft wide-angle camera using a spectral filter sensitive to wavelengths of infrared light centered at 752 nanometers. The view was obtained on July 2, 2006 at a distance of approx. 163.000 Km (about 101.000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 62°.
Image scale is roughly 19 Km (such as about 12 miles) per pixel.Lug 28, 2006
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Titan-Lakes-Unnamed_North_Polar_Lakes-01-PIA08630-2.jpgTitanian Northern Lakes (2)58 visiteCaption NASA originale:"For all these reasons, scientists interpret the dark areas as lakes of liquid methane or ethane, making Titan the only body in the Solar System besides Earth known to possess lakes. Because such lakes may wax and wane over time, and winds may alter the roughness of their surfaces. Repeat coverage of these areas should test whether indeed these are bodies of liquid.
These two radar images were acquired by the Cassini radar instrument in synthetic aperture mode on July 21, 2006.
The image (1) is centered near 80° North Lat. and 92° West Long.; it measures about 380x120 Km.
The image (2) is centered near 78° North Lat. and 18° West Long.; it measures about 425x120 Km.
Smallest details in this image are about 500 mt (roughly 1640 feet) across".Lug 25, 2006
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Titan-Lakes-Unnamed_North_Polar_Lakes-00-PIA08630.jpgTitanian Northern Lakes (1)57 visiteCaption NASA originale:"The Cassini spacecraft, using its radar system, has discovered very strong evidence for hydrocarbon lakes on Titan.
Dark patches, which resemble terrestrial lakes, seem to be sprinkled all over the high latitudes surrounding Titan's North Pole.
Scientists have speculated that liquid methane or ethane might form lakes on Titan, particularly near the somewhat colder Polar Regions. In the images, a variety of dark patches, some with channels leading in or out of them, appear. The channels have a shape that strongly implies they were carved by liquid. Some of the dark patches and connecting channels are completely black, that is, they reflect back essentially no radar signal, and hence must be extremely smooth. In some cases rims can be seen around the dark patches, suggesting deposits that might form as liquid evaporates. The abundant methane in Titan's atmosphere is stable as a liquid under Titan conditions, as is its abundant chemical product, ethane, but liquid water is not".Lug 25, 2006
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Titan-Rivers-Unnamed_Rivers_and_Channels-PIA08604-0.jpgCold Rivers58 visiteCaption NASA originale:"A network of river channels is located atop Xanadu, the continent-sized Region on Saturn's moon Titan.
This radar image was captured by the Cassini Radar Mapper on April 30, 2006.
These winding, meandering river channels start from the top of the image and run like a fork in the road, splitting to the right and left of the image. At Titan's chilly conditions, streams of methane and/or ethane might flow across parts of the Region.
The picture is roughly 230 Km (about 143 miles) wide by 340 Km (such as approx. 211 miles) long, and shows features as small as about 500 mt (approx. 1640 feet)".Lug 20, 2006
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