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| Piú votate - Titan: The "Foggy" Moon |
Titan-Shoreline_and_Drainage_Channels-04.jpgShoreline and Drainage Channels (Mosaic)55 visiteCaption ESA originale:"This composite was produced from images returned yesterday, 14 January 2005, by ESA's Huygens probe during its successful descent to land on Titan. It shows a full 360-degree view around Huygens. The left-hand side, behind Huygens, shows a boundary between light and dark areas. The white streaks seen near this boundary could be ground 'fog' of methane or ethane vapour, as they were not immediately visible from higher altitudes. As the probe descended, it drifted over a plateau (centre of image) and was heading towards its landing site in a dark area (right). This dark area is possibly a drainage channel which might still contain liquid material. From the drift of the probe, the wind speed has been estimated at around 6-7 mt per second. These images were taken from an altitude of about 8 Km with a resolution of about 20 mt per pixel".
(6 voti)
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Titan-Surface-30.jpgOn the surface of Titan55 visiteCaption ESA originale:"This raw image was returned by the ESA Huygens DISR camera after the probe descended through the atmosphere of Titan. It shows the surface of Titan with ice blocks strewn around. The size and distance of the blocks will be determined when the image is properly processed". Dunque Huygens ce l'ha fatta: è scesa su Titano! E la qualità di queste prime immagini supera le nostre più rosee aspettative: la visibilità è buona e questa parte di Titano sembra ricordarci - vagamente - la superficie di Venere, così come ripresa dalle Sonde Sovietiche "Venera".
(6 voti)
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Titan-Clouds-PIA06159.jpgTitanian Clouds (December 2004 fly-by)55 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".
(6 voti)
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Titan-PIA06151_modest.jpgTitan from about 810.000 Km54 visiteCaption NASA originale:"The bright and dark regions near the center of the frame are features on Titan's surface. The image has been processed to make features more visible. The surface contrast is degraded toward the edges of the disk due to the effects of Titan's smoggy atmosphere. The region seen here is similar to that seen during Cassini's first close flyby of Titan in October. The bright area toward the bottom of the image is the region dubbed "Xanadu." North is to the upper right.
The image was acquired at a distance of approximately 810.000 Km and the image scale is 4.8 Km per pixel". Ed ora una curiosità: guardate il bordo di Titano, in alto alla Vostra Dx, ad ore 2, c'è un rilievo rotondeggiante (una "cupola scura") perfettamente visibile. Non sembra un difetto della foto o un artifact derivante da vizio di processo e/o di compressione dell'immagine. E allora, secondo Voi, che cos'è?
(6 voti)
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Titan-Undefined_Surface_Features-Radar_View-PIA06995_modest.jpgAnother "radar view" from Titan: the "arrow"55 visiteOccorre la Caption NASA originale per tentare di capire qualcosa di questa "oscura" (da tutti i punti di vista) immagine radar di Titano: "...the (arrow-like) "feature" is approximately 30 Km across and it is formed from 2 straight lines that intersect. Looking more closely, one can distinguish other linear features that seem to follow the left side of the "arrow" and perhaps interact in some way with a dark spot. Straight lines may represent fractures or faults in the icy crust, or they may form from material that has flowed or has been shaped by wind, either recently or in the distant past.
The area shown is about 115 Km wide and 170 Km high and is located near 52° North latitude and 73° West longitude. This radar image is part of a larger strip of data acquired on Oct. 26, 2004, as Cassini passed Titan at a distance of 1.200 Km".
Secondo noi il rilievo che alla NASA chiamano "freccia" potrebbe essere una sorta di ciglio roccioso ma, come vedete Voi stessi, con un'immagine così...ogni ipotesi è buona!
(6 voti)
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Titan-PIA06123_modest.jpgTitan from about 1.000.000 Km (true colors)54 visitePer questa immagine riteniamo maggiormente utile ed interessante offrirVi la caption NASA originale:"The image was acquired at a distance of about 1 million kilometers (621,371 miles) in a near ultraviolet filter that is sensitive to scattering by small particles. The Sun preferentially illuminates the southern hemisphere at this time; the north polar region is in darkness. The well-known global detached haze layer, hundreds of kilometers above Titan's surface, is produced by photochemical reactions and is visible as a thin ring of bright material around the entire planet. At the northern high-latitude edge of the image, additional striations are visible, caused by particulates that are high enough to be illuminated by the Sun even though the surface directly below is in darkness. These striations may simply be caused by a wave propagating through the detached haze, or they may be evidence of additional regional haze or cloud layers not present at other latitudes".
(6 voti)
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Titan-South_Polar_Vortex-PIA17163-PCF-LXTT-IPF.jpgDouble Crescent (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/IPF)58 visiteTitan's South Polar Vortex mimics the moon itself, creating - as you can (barely) see in this frame, taken by the NASA - Cassini Spacecraft on December, 1, 2013 - a somehow elegant "crescent within a crescent". In fact, situated above the (surrounding) South Polar Atmosphere, the raised Walls of the Vortex, which stand along its Sunward Side, can just catch the grazing Sunlight, thus creating a "crescent" of its own. Titan (that, as you should know by now, is approx. 3200 miles - such as about 5149,88 Km - across) is Saturn's largest moon and possesses an extremely dense and ultra-dynamic Atmosphere, whose true characteristics are still a mistery.
Speaking of unanswered questions as well as problems which are still unsolved, we have to say - as IPF - that the true nature (---> meaning Seasonal or Permanent) of the South Polar Vortex keeps being, up to now, an highly controversial subject in the Planetary Scientists' Community. However, a definitive answer about the aforementioned question - and we like to say "obviously" -, will come, in a way or another, in time. For now, the only - truly - wise thing to do, is to keep looking...
This view looks toward the Trailing Hemisphere of Titan and North is up. The image was taken with the NASA - Cassini Spacecraft Wide-Angle Camera - as we wrote herebefore - on December, 1, 2013, by using a Spectral Filter which preferentially admits Wavelengths of Near-InfraRed Light centered at 939 nanometers. This frame was obtained at a distance of approximately 108.000 miles (such as about 173.808,72 Km) from Titan and the scale is roughly 6 miles (such as approx. 9,65 Km ) per pixel.
This frame (which is an Original NASA - CASSINI Spacecraft's b/w and NON Map-Projected image published on the NASA - Planetary Photojournal with the ID n. PIA 17163) has been additionally processed, contrast enhanced, magnified to aid the visibility of the details, Gamma corrected and then colorized - according to an educated guess (or, if you wish, an informed speculation) carried out by Dr Paolo C. Fienga - 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 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 other things, the existence of different Elements (Gases) present in the Atmosphere 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 Titan - as it is in this frame - would appear, to an average human eye, a little bit lower than it has been shown (or, better yet: interpreted) here.MareKromium
(5 voti)
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Titan-PIA16635-PCF-LXTT-IPF-1.jpgTitanian Northern Lakes (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)67 visiteThe Lakes existing on the Saturnian moon Titan, reflect Radio Waves in varying ways, as it can be noticed in this Radio-Image obtained by the the NASA - Cassini Spacecraft. Scientists think the variations in Reflectivity, or Brightness, have to be related with the smoothness (such as the so-called "texture") of the imaged Surface. However, if a Lake is fully liquid, it always looks VERY dark (actually black); but if it is only partially liquid, then it looks a lot brighter. In this frame, taken from Titan's High Northern Latitudes (such as at approx. 79° North Latitude and 58° West Longitude) on May, 22, 2012, the Lakes located on on the left (Sx) side of it are full of Liquid Hydrocarbons, while the ones - barely visible - located on the top right (Dx) of the picture are only partially filled - it has to be said, however, that what can be seen on the right side of the frame, could even be the representation of simple Saturated Ground (---> a Surface Feature - or, better yet, a Surface "Condition" - known as "Mudflat" ---> Mudflats or Mud Flats, also known as Tidal Flats, are Coastal Wetlands that form when huge quantities of Mud are deposited by the action of Oceanic Tides or particularly fast-flowing Rivers).
The Lakes visible in this image are each about 35 to 45 Km (such as approx. 22 to 30 miles) across, or about the size of Lake Tahoe, on the California-Nevada Border. Some of the differences in Reflectivity could also be explained by the presence, in the Lakes, of floating blocks of Hydrocarbon Ice. The image was obtained by the Cassini Radar Mapper at a scale of about 350 meters (1100 feet) per pixel.
This frame (which is a crop obtained by an Original NASA - CASSINI Spacecraft Radio-Image published on the NASA - Planetary Photojournal with the n. PIA 16635), since it is just a Radio-Image of the Titanian Surface and NOT a real view of it, has been colorized, according to an educated guess, by Dr Paolo C. Fienga (LXTT-IPF), in what they could reasonably be its possible Absolute Natural Colors (such as the colors that a human eye would perceive if someone were onboard the NASA - CASSINI Spacecraft and, once the thick layer of Titanian Hazes and Fogs shall have been completely overcome, looked down, towards the Surface of Titan itself), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.MareKromium
(5 voti)
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Titan-N00172750-N00172779-GB-LXTT.gifPassing-by... (a GIF-Movie by Dr Gianluigi Barca - Lunexit Team)208 visitenessun commentoMareKromium
(5 voti)
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Titan_and_Callistus-PIA13896.jpgTitan and Callistus (a Mosaic by NASA/JPL)231 visiteCaption NASA:"These images compare Surface Features observed by NASA's Cassini Spacecraft at the Xanadu Region on Saturn's moon Titan (left), and Features observed by NASA's Galileo Spacecraft on Jupiter's cratered moon Callistus (right).
The Cassini Radar Image, obtained during a Titan Fly-By occurred on April, 30th, 2006, is centered at about 10° South Latitude and 85° West Longitude.
The Galileo Camera Image, obtained on June 25, 1997, is centered at about 6° South Latitude and 7° West Longitude.
Titan may originally have had a cratered landscape similar to Callisto that has since been eroded by Rainfall and Runoffs. There are many large Circular Features in Titan's Xanadu Region that have some of the characteristics of impact craters - such as Central Peaks and inward-facing Circular Cliffs - which make scientists think they are, in fact, eroded Impact Craters. The Surface of Callisto also has a substantially eroded cratered landscape". MareKromium
(5 voti)
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Titan-Lakes-Ontario_Lacus-00-PIA13172.jpgOntario Lacus69 visiteThis image of Ontario Lacus, the largest lake on the Southern Hemisphere of Saturn's moon Titan, was obtained by NASA's Cassini Spacecraft on Jan. 12, 2010.
North is up in this image. Objects appear bright in this radar image when they are tilted toward the Spacecraft or have rough surfaces. The lake surface appears dark because it is smooth. The Northern Shoreline features flooded River Valleys and Hills as high as about 1 Km (3000 feet).
A smooth, wave-sculpted Shoreline, like that seen on the S/Eastern side of Lake Michigan, can here be seen on the N/Eastern side of the lake.
Smooth lines parallel to the current shoreline could be formed by low waves over time, which were likely driven by winds sweeping in from the West or South-West.
The S/Eastern shore features a round-headed Bay intruding into the shore. The liquid-filled depressions appear to be relatively recent.
The middle part of the Western Shoreline shows the first well-developed Delta observed on Titan. The shape of the Delta shows that liquid flowing down from a higher plain has switched Channels on its way into the Lake, forming at least two lobes. Examples of this kind of Channel switching and wave-modified deltas can be found on Earth at the Southern end of Lake Albert between Uganda and the Democratic Republic of Congo in Africa and the remains of an ancient lake known as Megachad in the African country Chad.
Titan is the only other world in our Solar System known to have standing bodies of liquid on its Surface. Because Surface temperatures at the Poles average a chilly 90 Kelvin (about minus 300 degrees Fahrenheit), the liquid is a combination of Methane, Ethane and Propane, rather than water.
Ontario Lacus has a surface area of about 15.000 square Km (approx. 6000 square miles), slightly smaller than its terrestrial namesake, Lake Ontario.MareKromium
(5 voti)
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Titan-N00156687-88-89-MF-PCF-LXTT.jpgWatching through the Fog... (Absolute Natural Colors; credits for the additional process. and color.: Drr Marco Faccin and Paolo C. Fienga - Lunexit Team)64 visitenessun commentoMareKromium
(5 voti)
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