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| Piú viste - Titan: The "Foggy" Moon |
Titan-PIA07542-PCF-LXTT.jpgTitan (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)163 visitenessun commentoMareKromium
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Titan-Clouds-Rain_Clouds-PIA12819.jpgThe "Rain Season" on Titan161 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-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)157 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-Equatorial_Clouds-PIA12810.jpgTitan's Equatorial Clouds 146 visiteCaption NASA:"NASA's Cassini Spacecraft chronicles the change of Seasons as it captures Clouds concentrated near the Equator of Saturn's largest moon, Titan.
Methane Clouds in the Troposphere, the lowest part of the Atmosphere, appear white here and are mostly near Titan's Equator. The darkest areas are Surface Features that have a low albedo, meaning they do not reflect much light.
Cassini observations of Clouds like these provide evidence of a seasonal shift of Titan's weather systems to low latitudes following the August 2009 Equinox in the Saturnian System (during Equinox, the Sun lies directly over the Equator (see PIA11667 to learn how the Sun's illumination of the Saturnian System changed during the Equinox transition to Spring in the Northern Hemispheres and to Fall in the Southern Hemispheres of the Planet and its moons).
In 2004, during Titan's late Southern Summer, extensive Cloud Systems were common in Titan's South Polar Region (see PIA06110, PIA06124 and PIA06241). Since 2005, Southern Polar Systems have been observed infrequently, and one year after the Equinox, extensive near-equatorial Clouds have been seen.
This image was taken on Oct. 18, 2010, a little more than one Earth year after the Saturnian Equinox, which happens once in roughly 15 Earth years.
The cloud patterns observed from late Southern Summer to early Southern Fall on Titan suggest that Titan's Global Atmospheric Circulation is influenced by both the Atmosphere and the Surface. The temperature of the Surface responds more rapidly to changes in illumination than does the thick Atmosphere. Outbreaks such as the Clouds seen here may be the Titan equivalent of what creates the Earth's tropical rainforest climates, even though the delayed reaction to the change of seasons and the apparently sudden shift is more reminiscent of the behavior over Earth's tropical oceans than over tropical land areas.
A few clouds can be seen in Titan's Southern Latitudes here and some clouds are also visible in the high Northern Latitudes.
This view looks toward the Saturn-facing side of Titan (approx. 5150 Km or 3198,15 miles across). North is up. The image appears slightly grainy because it was re-projected to a scale of about 6 Km (3,726 miles) per pixel. Scale in the original image was approx. 15 Km (9,315 miles) per pixel.
This view consists of an average of three images taken using a filter sensitive to Near-InfraRed Light centered at 938 nanometers, which allows for detection of Titan's Surface and Lower Atmosphere, plus an image taken using a filter sensitive to Visible Light centered at 619 nanometers.
The images were taken with the Cassini spacecraft's narrow-angle camera at a distance of approx. 2,5 MKM (1.552.500 MMs) from Titan and at a Sun-Titan-Spacecraft, or Phase, Angle of 56°".MareKromium
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Titan-PIA14913-1.jpgThe South Polar Atmosphere of Titan (EDM - Natural Colors; credits: NASA/JPL-Caltech/Space Science Institute)146 visitenessun commentoMareKromium
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Titan-PIA12764.jpgEthereal Ring (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)142 visiteCaption NASA:"The Cassini Spacecraft looks toward the Dark Side of Saturn's largest moon and captures the halo-like ring produced by Sunlight scattering through the periphery of Titan's Atmosphere. A detached, high-altitude Global Haze Layer encircles Titan. This view looks toward the Trailing Hemisphere of Titan (approx. 5150 Km, or 3198,15 miles across). North on Titan is up.
The image was taken with the Cassini Spacecraft narrow-angle camera on Nov. 26, 2010 using a spectral filter sensitive to wavelengths of UltraViolet Light centered at 338 nanometers. The view was obtained at a distance of approx. 1,9 MKM (such as about 1,179 MMs) from Titan and at a Sun-Titan-Spacecraft, or Phase, Angle of 154°.
Image scale is roughly 12 Km (7,452 miles) per pixel".MareKromium
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Titan-PIA21902.jpgThe uneven Atmosphere of Titan139 visiteLe diverse stratificazioni dell'Alta Atmosfera di Titano sono ben visibili in questa foto CASSINI dell'ormai lontano AD 2005.
In questo frame, ci appare del tutto evidente che la densità dell'Atmosfera di Titano NON é strettamente correlata all'altezza della stessa (ergo delle sue nuvole e nebbie) rispetto al Datum (Altitudine Zero); le turbolenze (e quindi anche la composizione chimica dell'Atmosfera) sembrano estendersi e rivolgersi, a volte, da strati più bassi verso quelli più alti, mentre, in altri casi, sembra avvienire esattamente l'opposto.
Questa conclusione é stata basata sull'esame di immagini sequenziali che coprissero la medesima Regione Titaniana per svariati minuti (o decine di minuti). In questo frame le innumerevoli "disomogeneità" sono del tutto palesi.
Non possiamo neppure escludere l'esistenza di (violentissime) correnti convettive le cui cause, tuttavia, non sono ancora chiare.
Caption NASA Originale:"In this view, individual Layers of Haze can be distinguished in the Upper Atmosphere of Titan, Saturn's largest moon. Titan's Atmosphere features a rich and complex chemistry originating from Methane and Nitrogen (---> Azoto) and evolving into complex molecules, eventually forming the "Smog! that surrounds the moon (even at extremely lower altitudes).
This Natural Color image was taken in Visible Light with the Cassini Spacecraft wide-angle camera on March 31, 2005, at a distance of approximately 20.556 miles (such as about 33.081,67 Km) from Titan. The view looks toward the North Polar Regions on the moon's Night-Side. Part of Titan's sunlit crescent is visible at right (Dx).
The Cassini Spacecraft ended its mission on Sept. 15, 2017".MareKromium
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Titan-Clouds-Rain_Clouds-PIA12818-01.jpgTitanian "Deluge"138 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_and_Dione-PIA14912.jpgTitan and Dione (Natural Colors; credits: NASA/JPL-Caltech/Space Science Institute)138 visiteCaption NASA:"Saturn's largest moon, Titan, appears deceptively small paired here with Dione, Saturn's third-largest moon, in this view from NASA's Cassini Spacecraft. Titan (which is approx. 3200 miles or about 5150 Km across) is much farther from the Spacecraft than Dione (that, on its side, is approx. 698 miles or about 1123 KM across) is in this view. The view was captured at a distance of approx. 684.000 miles (such as about 1,1 MKM) from Titan but only about 85.000 miles (such as approx. 136.000 Km) from Dione.
Titan appears in its True Colors, but it has been brightened by a factor of about 1,6 relative to Dione. This view looks toward the Saturn-facing side of Titan and the area between the Saturn-facing side and Leading Hemisphere of Dione. North is up on both moons.
Images taken using red, green and blue spectral filters were combined to create this Natural Color view. The images were obtained with the Cassini Spacecraft wide-angle camera on Nov. 6, 2011. Scale in the original image was roughly 5 miles (such as approx. 8 Km) per pixel on Dione and roughly 41 miles (about 66 Km) per pixel on Titan. The image has been magnified by a factor of 1,5 and contrast-enhanced to aid visibility".MareKromium
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Titan-W00074172-79-MF-EB-LXTT-IPF-3.jpgPossible Aurora at Titan (an Image-Mosaic by Elisabetta Bonora and Marco Faccin/Lunexit Team)137 visitenessun commentoMareKromium
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Titan-PIA21624.jpgDouble Titan137 visiteCaption NASA:"These two views of Saturn's moon Titan exemplify how NASA's Cassini Spacecraft has revealed the Surface of this fascinating world.
Cassini carried several instruments to pierce the veil of hydrocarbon haze that enshrouds Titan. These include the Spacecraft's Radar and the Visual and InfraRed Mapping Spectrometer, or VIMS. The mission's imaging cameras also have several spectral filters sensitive to specific wavelengths of InfraRed Light that are able to make it through the Haze to the Surface and back into space. These "spectral windows" have enable the imaging cameras to map nearly the entire surface of Titan.
In addition to Titan's Surface, images from both the imaging cameras and VIMS have provided windows into the moon's ever-changing Atmosphere, chronicling the appearance and movement of Hazes and Clouds over the years. A large, bright and feathery band of Summer Clouds can be seen arcing across high Northern Latitudes in the view at right (Dx).
These views were obtained with the Cassini Spacecraft Narrow-Angle Camera on March 21, 2017. Images taken using red, green and blue spectral filters were combined to create the Natural-Color View on the left (Sx).
The false-color view at right (Dx) was made by substituting an InfraRed image (centered at 938 nanometers) for the red color channel.
The views were acquired at a distance of approx. 613.000 miles (such as a little more than 986.000 Km) from Titan and the Image Scale is roughly 4 miles (such as approx. 6,437 Km) per pixel".MareKromium
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Titan-Regions-Belet_Region-PIA12647.jpgBelet Region (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)136 visiteCaption NASA:"The Cassini Spacecraft peers through the Atmosphere of Saturn's largest moon, Titan, to examine the Dark Region known as "Belet".
This large Region has a low albedo, meaning it reflects little light.
See also PIA11149 to learn more. This view looks toward the Trailing Hemisphere of Titan.
The image was taken with the Cassini Spacecraft narrow-angle camera on Dec. 28, 2009 using a spectral filter sensitive to wavelengths of Near-InfraRed Light centered at 938 nanometers. The view was obtained at a distance of approx. 282.000 Km (about 175.000 miles) from Titan and at a Sun-Titan-Spacecraft, or Phase, Angle of 45°.
Image scale is roughly 2 Km (a little more than 1 mile) per pixel".MareKromium
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