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Titan-Lakes-South_Polar_Lake-00-PIA06240.jpgOntario Lacus and the South Polar Regions of Titan56 visiteThis view of Titan's South Polar Region reveals an intriguing dark feature that may be the site of a past or present lake of liquid hydrocarbons.
The true nature of this feature, seen here at left of center, is not yet known, but the shore-like smoothness of its perimeter and its presence in an area where frequent convective storm clouds have been observed by Cassini and Earth-based astronomers make it the best candidate thus far for an open body of liquid on Titan.
If this interpretation is correct, then other very dark but smaller features seen in the South Polar Region, some of which are captured in this image, may also be the sites of liquid hydrocarbon reservoirs.
In addition to the notion that the dark feature is or was a lake filled with liquid hydrocarbons, scientists have speculated about other possibilities. For instance, it is plausible that the lake is simply a broad depression filled by dark, solid hydrocarbons falling from the atmosphere onto Titan's surface. In this case, the smoothed outline might be the result of a process unrelated to rainfall, such as a sinkhole or a volcanic caldera.
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Titan-Lakes-South_Polar_Lake-01-PIA06241-PCF-LXTT-IPF-000.jpgOntario Lacus and the South Polar Regions of Titan56 visiteCaption NASA originale:"Although it is far too cold for blossoming flowers, summer does bring storm clouds and presumably rain to Titan's south polar region.
The observed persistence of convective storm activity in the region during the Southern Titan Summer has led scientists to speculate that the dark, footprint-shaped feature near the upper left could be a past or present reservoir for Titan's methane rains".
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Titan-Lakes-South_Polar_Lake-01-PIA06241-PCF-LXTT-IPF-001.jpgOntario Lacus and the South Polar Regions of Titan (Absolute Natural Colors; credits for the additional process. and color. Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)92 visiteThis view of Titan’s South Pole reveals the intriguing Dark Feature named Ontario Lacus and a host of smaller features dotting the whole South Polar Region. The true nature of this Surface Feature, seen here at left of center, is not yet known with absolute certainty. However, the Feature’s extremely dark coloration, the shore-like smoothness of its perimeter, and its presence in an area where frequent Convective Storm Clouds have been observed by the NASA - Cassini Spacecraft and Earth-based telescopes, made it the best candidate for an open body of liquid on Titan when this image was taken, in June 2005. This interpretation has, afterwards, been strengthened by the sighting of Surface Features having similar morphologies, but this time in Titan’s North Polar Regions during the Fly-By of this Saturnian moon that occurred in late February of the AD 2007. The possibility that those Northern Features, the sizes of small Seas, are either completely or partially filled with Liquid Hydrocarbons has been significantly strengthened also by the Radar Data collected by Cassini and which overlap portions of the Northern Features seen by the Cassini's Imaging Science Subsystem.
Previously, scientists had speculated that Ontario Lacus might simply be a Broad Depression filled by dark, Solid Hydrocarbons falling from the Atmosphere onto Titan’s Surface. In this case, the smoothed outline might be the result of a process unrelated to Rainfall, such as a so-called "Sinkhole" (---> a cavity in the ground, especially in a limestone formation, caused by water erosion and providing a route for Surface Water to disappear) or a "Volcanic Caldera". However, the strong likelihood that the Dark and Smooth North Polar Features are actually Lakes and Seas has made imaging scientists more confident that Ontario Lacus, and the smaller Dark Features dotting the South Polar Regions of Titan, also hold liquid. If correct, this new revelation would mean that each Pole on Titan is, in fact, a large Wetlands Area. The brightest (and almost white) Features seen here (from about 3 to 6 o'clock of the picture), are Methane Clouds (perhaps mixed with Water-Ice Clouds).
The original frame that we show you today, was taken by the NASA - Cassini Spacecraft during the distant Fly-By of Titan that took place in June 6, of the AD 2005, by using a combination of Spectral Filters sensitive to Wavelengths of Polarized InfraRed Light, allowing Cassini to see through the obscuring smog of Titan's Atmosphere and all the way down to the Surface. The image was acquired from an approximate distance of 450.000 Km (such as about 279.450 miles) from Titan. Resolution in the original image is approximately 3 Km (such as 1,863 miles) per pixel.
This picture (which is an Original NASA - Cassini Spacecraft b/w frame published on the NASA - Planetary Photojournal and identified by the n. PIA 06241) has been additionally processed and then colorized, according to an educated guess carried out by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Cassini Spacecraft and then looked outside, towards the South Polar Region of the Saturnian moon Titan), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present in the Atmosphere and on the Surface of Titan, each having a different Albedo (---> Reflectivity) and Chemical Composition.
Note: it is possible (but we, as IPF, have no way to be one-hundred-percent sure of such a circumstance), that the actual luminosity of the Albedo Features seen in this frame would appear, to an average human eye, way lower than it has been shown (better yet: interpreted) here.MareKromium
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Titan-Lakes-South_Polar_Lake-01-PIA06241-PCF-LXTT-IPF-002.jpgOntario Lacus and the South Polar Regions of Titan: after the Fog (Absolute Natural Colors; credits for the additional process. and color. Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)96 visiteThis view of Titan’s South Pole reveals the intriguing Dark Feature named Ontario Lacus and a host of smaller features dotting the whole South Polar Region. The true nature of this Surface Feature, seen here at left of center, is not yet known with absolute certainty. However, the Feature’s extremely dark coloration, the shore-like smoothness of its perimeter, and its presence in an area where frequent Convective Storm Clouds have been observed by the NASA - Cassini Spacecraft and Earth-based telescopes, made it the best candidate for an open body of liquid on Titan when this image was taken, in June 2005. This interpretation has, afterwards, been strengthened by the sighting of Surface Features having similar morphologies, but this time in Titan’s North Polar Regions during the Fly-By of this Saturnian moon that occurred in late February of the AD 2007. The possibility that those Northern Features, the sizes of small Seas, are either completely or partially filled with Liquid Hydrocarbons has been significantly strengthened also by the Radar Data collected by Cassini and which overlap portions of the Northern Features seen by the Cassini's Imaging Science Subsystem.
Previously, scientists had speculated that Ontario Lacus might simply be a Broad Depression filled by dark, Solid Hydrocarbons falling from the Atmosphere onto Titan’s Surface. In this case, the smoothed outline might be the result of a process unrelated to Rainfall, such as a so-called "Sinkhole" (---> a cavity in the ground, especially in a limestone formation, caused by water erosion and providing a route for Surface Water to disappear) or a "Volcanic Caldera". However, the strong likelihood that the Dark and Smooth North Polar Features are actually Lakes and Seas has made imaging scientists more confident that Ontario Lacus, and the smaller Dark Features dotting the South Polar Regions of Titan, also hold liquid. If correct, this new revelation would mean that each Pole on Titan is, in fact, a large Wetlands Area. The brightest (and almost white) Features seen here (from about 3 to 6 o'clock of the picture), are Methane Clouds (perhaps mixed with Water-Ice Clouds).
The original frame that we show you today, was taken by the NASA - Cassini Spacecraft during the distant Fly-By of Titan that took place in June 6, of the AD 2005, by using a combination of Spectral Filters sensitive to Wavelengths of Polarized InfraRed Light, allowing Cassini to see through the obscuring smog of Titan's Atmosphere and all the way down to the Surface. The image was acquired from an approximate distance of 450.000 Km (such as about 279.450 miles) from Titan. Resolution in the original image is approximately 3 Km (such as 1,863 miles) per pixel.
This picture (which is an Original NASA - Cassini Spacecraft b/w frame published on the NASA - Planetary Photojournal and identified by the n. PIA 06241) has been additionally processed and then colorized, as if the yellowish Fogs that surrounds the planet had been overcome. The colorization, even in this case, has been made according to an educated guess carried out by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Cassini Spacecraft and then looked outside, towards the South Polar Region of the Saturnian moon Titan), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present in the Atmosphere and on the Surface of Titan, each having a different Albedo (---> Reflectivity) and Chemical Composition.
Note: it is possible (but we, as IPF, have no way to be one-hundred-percent sure of such a circumstance), that the actual luminosity of the Albedo Features seen in this frame would appear, to an average human eye, way lower than it has been shown (better yet: interpreted) here.MareKromium
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Titan-Lakes-South_Polar_Unnamed_Lake-PIA12162.jpgLake-like Feature near the South Pole of Titan54 visiteCaption NASA:"This mosaic of image swaths from Cassini's Titan Radar Mapper, taken with the Synthetic-Aperture Radar (SAR), features a large Dark Region several hundred kilometers across that differs in several significant ways from potential lakes observed on Titan.
It is not as dark to the radar as many lakes (including lakes seen here), and the nature of the margin is unusual. It has many characteristics in common with lakes, including its channels and interior, yet its differences distinguish it from other similar features. Some similarities are seen with the dark feature in Titan pass T7 (see PIA03563).
At top (North), the feature has characteristics of a shoreline, with round bay-like margins and channels that drain into it; at left (West) and right (East) it is rimmed by bright, feathery, branching channel-like structures, some of which extend for tens of kilometers. Within the Dark Feature some details can be seen, some of which seem to be extensions of the channels draining into the Dark Feature.
The mosaic is near the South Pole, centered near 82° South and 205° West. It includes data from Titan passes T39, T55, T57, T58, and T59, collected between December 2007 and July 2009. The individual swaths vary in resolution and illumination angle, so the edges are visible and surface features look somewhat different across swath boundaries, but the regional view can still be understood. As more SAR image swaths of Titan are collected by Cassini, mosaics of those images reveal features that cannot be appreciated within the individual observations".MareKromium
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Titan-Lakes-South_Polar_Unnamed_Lakes-PIA11147.jpgChanges in the Titanian Lakes55 visiteCaption NASA:"These mosaics of the South Pole of Saturn's moon Titan, made from images taken almost one year apart, show changes in dark areas that may be lakes filled by seasonal rains of liquid hydrocarbons.
The images on the left (unlabeled at top and labeled at bottom) were acquired July 3, 2004. Those on the right were taken June 6, 2005. In the 2005 images, new dark areas are visible and have been circled.
The very bright features are clouds in the lower Atmosphere (the Troposphere). Titan's clouds behave similarly to those on Earth, changing rapidly on timescales of hours and appearing in different places from day to day. During the year that elapsed between these two observations, clouds were frequently observed at Titan's
South Pole by observers on Earth and by Cassini's imaging science subsystem (see also PIA06124).
It is likely that rain from a large storm created the new dark areas that were observed in June 2005. Some features, such as Ontario Lacus, show differences in brightness between the two observations that are the result of differences in illumination between the two observations. These mosaics use images taken in InfraRed Light at a wavelength of 938 nanometers.
The images have been oriented with the South Pole in the center (black cross) and the 0° Meridian toward the top.
Image resolutions are several kilometers per pixel".MareKromium
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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
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Titan-Lakes-Unnamed_North_Polar_Lakes-00-PIA08630.jpgTitanian Northern Lakes (1)54 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".
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Titan-Lakes-Unnamed_North_Polar_Lakes-01-PIA08630-2.jpgTitanian Northern Lakes (2)55 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".
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Titan-Lakes-Unnamed_North_Polar_Lakes-02-PIA01942.jpgTitanian Northern Lakes (3)55 visiteCaption NASA originale:"Using its radar system, the Cassini spacecraft has imaged new lakes on Titan.
The large dark patch seen on this image, at high latitudes surrounding Titan's North Pole, is most likely a hydrocarbon lake. Several dark channels can be seen; the longest one at the left meanders over almost 100 Km (about 62 miles), and appears to drain into the lake. Some dark channels are remarkably straight, suggesting possible faulting in the subsurface. The bright landforms jutting into the lake indicate that old, eroded landforms may have flooded.
This radar image was acquired by the Cassini radar instrument in synthetic aperture mode on Oct. 9, 2006. The image is centered near 73° North Latitude and 343° West Longitude; it measures about 300 by 140 Km (such as about 190 by 90 miles). Smallest details in this image are about 500 mt (approx. 1.640 feet) across".
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Titan-Lakes-Unnamed_North_Polar_Lakes-04-PIA01943.jpgTitanian Northern Lakes (4)57 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".
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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".
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