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| Piú votate - Titan: The "Foggy" Moon |
Titan-IMG001935-PCF-LXTT.jpgTitan during Fly-By n. 9 (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)175 visiteOriginal NASA caption:"This image was taken on December 26, 2005 and received on Earth December 27, 2005. The camera was pointing toward TITAN that, at the time, was approximately 57.509 Km (about 35.734 miles) away.
This image was taken using the CB3 and CL2 filters and has not been validated or calibrated".MareKromium
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Titan-PIA12775-PCF-LXTT.jpgTitan's North Polar "Hood" (Darkened Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)114 visiteCaption NASA:"The Cassini spacecraft examines Titan's north polar hood, the part of the atmosphere of Saturn's largest moon appearing dark at the top of this image. This view looks toward the Anti-Saturn Side of Titan.
North on Titan is up. The South Pole of Titan is going into darkness, with the Sun advancing towards the North with each passing day. The upper layer of Titan's Hazes is still illuminated by Sunlight scattered off the Planet.
The image was taken in Visible Violet Light with the Cassini Spacecraft wide-angle camera on April 19, 2011. The view was acquired at a distance of approx. 137.000 Km (about 85.000 miles) from Titan and at a Sun-Titan-Spacecraft, or Phase, Angle of 18°. Image scale is roughly 8 Km (about 5 miles) per pixel".MareKromium
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Titan-Clouds-North_Polar_Clouds-PIA12812-PCF-LXTT.jpgNorth Polar Clouds (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)159 visiteCaption NASA:"Clouds move above Titan's large Methane Lakes and Seas near the Planet's North Pole. Methane Clouds in the Troposphere, such as the lowest part of the Atmosphere, appear white here and are moving East over several of Titan's large Northern Lakes. The darkest areas are Lakes and Seas of liquid Methane, identifiable because they have a low albedo, meaning they do not reflect much light (the difference in brightness and darkness on the Surface here indicates a difference in its composition).
The clouds seen near Lakes and Seas suggest that Titan may have "Lake-effect" Clouds created by weather systems over large bodies of liquid.
However, without earlier observations to show the Clouds did not originate West of the large Sea "Kraken Mare", scientists cannot determine conclusively if these clouds are really "Lake-effect" Clouds.
If full, Kraken Mare, at about 400.000 square Km (248.400 square miles), would be almost five times the size of North America's Lake Superior.
Even if these Clouds are not directly connected to the Lakes and Seas, scientists think that frequent detections of Clouds at High Northern Latitudes since 2007 are related to the abundant availability of Methane at the Surface in this Region.
This view is centered on Terrain at 49° North Latitude and 179° West Longitude. The North Pole is near the upper right. The Clouds are visible above Terrain at about 60 to 82° North Latitude and 220 to 260° West Longitude. Scientists calculate wind speeds from about 0,5 to about 10 meters per second (such as from about 1 to 22 miles per hour), based on tracking of individual cloud features in different images.
Other Cassini observations of Clouds in Titan's Southern Latitudes provide evidence of a Seasonal Shift of Titan's Weather Systems to low Latitudes from higher, South Polar Latitudes following the August 2009 Equinox in the Saturnian System.
This image was taken with the Cassini Spacecraft narrow-angle camera using a spectral filter sensitive to wavelengths of Near-InfraRed Light centered at 938 nanometers. The view was obtained at a range of distances from approx. 406.000 Km (such as 252.126 miles) to approx. 796.000 Km (such as 494.316 miles) from Titan.
Scale is about 2 Km (1,242 miles) per pixel".MareKromium
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Titan-Clouds-Rain_Clouds-PIA12818-01.jpgTitanian "Deluge"141 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
(1 voti)
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Titan-Clouds-PIA13400.jpgTitanian Clouds (False Colors; credits: NASA/JPL/University of Arizona/University of Nantes/University of Paris Diderot)94 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
(1 voti)
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Titan-PIA12695.jpgThe strange Atmosphere of Titan (possible True Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)75 visiteCaption NASA:"The Cassini Spacecraft examines the characteristics of Titan's Atmosphere as it peers at Saturn's largest moon using a filter sensitive to Visible Violet Light.
This image shows Atmospheric Banding around Titan's North Pole and reveals hints of the moon's seasonal Hemispheric Dichotomy near the Equator. (to learn more about the Northern Bands, please refer to images PIA08868 and PIA08928).
This view looks toward the anti-Saturn side of Titan. North on Titan is up and rotated 23° to the left.
The image was taken in Visible Violet Light with the Cassini Spacecraft wide-angle camera on June 21, 2010. The view was obtained at a distance of approx. 170.000 Km (about 106.000 miles) from Titan and at a Sun-Titan-Spacecraft, or Phase, Angle of 33°.
Image scale is roughly 10 Km (about 6,2 miles) per pixel".MareKromium
(1 voti)
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Titan-Clouds-MF-LXTT.gifExtremely Bright Clouds Formation over Aztlan and Senkyo (a GIF-Movie by Marco Faccin - Lunexit Team)58 visitenessun commentoMareKromium
(1 voti)
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Titan-Crescent-EB-N00154034.jpgRising from the Rings... (Natural Colors; credits for the additional process. and color.: Elisabetta Bonora - Lunexit Team)105 visitenessun commentoMareKromium
(1 voti)
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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".
(1 voti)
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Titan-Atmosphere-IMG001498-br500.jpgComplex Hydrocarbons in Titan's upper atmosphere57 visiteCaption NASA originale:"During its closest flyby of Saturn's moon Titan on April 16, the Cassini spacecraft came within 1.025 Km of the moon's surface and found that the outer layer of the thick, hazy atmosphere is brimming with complex hydrocarbons.
This figure shows a mass spectrum of Titan's ionosphere near 1.200 Km above its surface. The mass range covered goes from Hydrogen at 1 atomic mass unit per elementary charge (Dalton) to 99 Daltons. This mass range includes compounds with 1, 2, 3, 4, 5, 6 and 7 carbons as the base structure (as indicated in the figure label). The identified compounds include multiple carbon molecules and carbon-nitrogen bearing species as well".
Un'atmosfera "primordiale", dunque, ma teoricamente idonea per lo sviluppo di forme di vita 'prossime' (in termini di fondamenta chimiche e chimico/fisiche) alle nostre concezioni di 'forme vitali'.
(1 voti)
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Titan-Close Up 6.jpgTitan's fly-by "A" - Close-up 655 visitenessun commento
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Titan-Close Up 4.jpgTitan's fly-by "A" - Close-up 454 visiteIn questo frame si vedono chiaramente almeno 5 crateri, ma è uno, in particolare, che ci ha colpito per il colore molto scuro del suo bordo e per la sua forma, perfettamente circolare.
Ma siamo certi che si tratti di crateri? E se fossero, invece, dei camini vulcanici simili a quelli che caratterizzano la superficie di Io?
Occorrono altre immagini, da distanza maggiormente ravvicinata per poter dire qualcosa di più. In ogni caso Titano si dimostra un mondo favvero intrigante ed affascinante; molto di più di quanto noi stessi ci potessimo attendere...
(1 voti)
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