| Piú viste - Titan: The "Foggy" Moon |
Titan-W00003515.jpgFrom the Dark Side... (Natural Colors; credits: Lunar Explorer Italia)55 visitenessun commentoMareKromium
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Titan-Clouds-02.jpgTitan's South Polar Cloud Burst55 visiteThis InfraRed image of Saturn's moon Titan shows a large burst of clouds in the moon's South Polar Region. These clouds form and move much like those on Earth, but in a much slower, more lingering fashion, new results from NASA's Cassini Spacecraft show.
This image is a color composite, with red shown at a 5-micron wavelength, green at 2.7 microns and blue at 2 microns. An InfraRed color mosaic is also used as a background image (red at 5 microns, green at 2 microns, blue at 1.3 microns).
The images were taken by Cassini's visual and InfraRed Mapping Spectrometer during a flyby of Titan on March 26, 2007, known as T27.
Titan's Southern Hemisphere still shows a very active meteorology (the cloud appears in white-reddish tones) even in 2007. According to climate models, these clouds should have faded out since 2005.
Scientists have monitored Titan's Atmosphere for 3-and-a-half years, between July 2004 and December 2007, and observed more than 200 clouds.
The way these clouds are distributed around Titan matches scientists' global circulation models. The only exception is timing — clouds are still noticeable in the Southern Hemisphere while Fall is approaching.
Scientists will continue to observe the long-term changes during Cassini's extended mission, which runs until the fall of 2010.MareKromium
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Titan-Volcanic_Features-PIA12111.jpgSouth Polar Basin55 visiteCaption NASA:"An enigmatic large Basin appears in the South Polar Region of Saturn's moon Titan at the center of this Titan Radar Mapper image from NASA's Cassini Spacecraft acquired on June 22, 2009.
The Basin has several possible origins.
It may be a Volcanic Caldera, produced by collapse after cryovolcanic eruptions.
It might be a Modified Impact Basin, partially infilled with sedimentary material.
Alternately, the basin may have formed by some other collapse process related to the presence of Subsurface Methane.
Evidence for lakes elsewhere on Titan suggests that it might have been later partially filled with liquid Methane and Ethane".
MareKromium
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Titan-PIA11594.jpgNorthern Layers (UV + Natural Colors; credits: Lunexit)55 visiteCaption NASA:"This UltraViolet view of Titan shows the moon's North Polar "Hood" (---> cappuccio) and its detached, high-altitude haze layer. See also PIA08137 to learn more.
This view looks toward the Saturn-facing side of Titan.
North on Titan is up and rotated 2° to the left.
The image was taken with the Cassini Spacecraft narrow-angle camera on Aug. 13, 2009 using a spectral filter sensitive to wavelengths of UltraViolet Light centered at 338 nanometers. The view was acquired at a distance of approx. 2,2 MKM (about 1,4 MMs) from Titan and at a Sun-Titan-Spacecraft, or Phase, Angle of 61°.
Image scale is roughly 26 Km (about 16 miles) per pixel".MareKromium
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Titan-PIA11603.jpgSeasonal Changes on Titan (Natural Colors; credits: NASA/JPL/Space Science Institute)55 visiteSeasonal changes in the Atmosphere of Saturn's largest moon are captured in this Natural Color image, which shows Titan with a slightly darker top half and a slightly lighter bottom half.
Titan's Atmosphere has a seasonal hemispheric dichotomy, and this image was taken shortly after Saturn's August 2009 Equinox.
Images taken using red, green and blue spectral filters were combined to create this Natural Color view.
Scientists have found that the Winter Hemisphere typically appears to have more high-altitude haze, making it darker at shorter wavelengths (UltraViolet through blue) and brighter at InfraRed wavelengths.
The switch between dark and bright occurred over the course of a year or two around the last Equinox. Scientists are studying the mechanism responsible for this change, and will monitor the dark-light difference as it flip-flops now that the 2009 Equinox has signaled the coming of Spring and then Summer in the Northern Hemisphere.
Although this hemispheric boundary appears to run directly East-West near the Equator, its position is not level with latitude and is actually offset from the Equator by about 10° of Latitude.
This view looks toward the Saturn-facing side of Titan. North on Titan is up.
The images were obtained with the Cassini Spacecraft wide-angle camera on Aug. 25, 2009 at a distance of approx. 174.000 Km (such as about 108.000 miles) from Titan.
Image scale is roughly 10 Km (a little more than 6 miles) per pixel.MareKromium
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Titan-PIA11622.jpgTitan's Atmospheric Layers55 visiteCaption NASA:"Saturn's moon Titan displays a detached, high-altitude global Haze Layer which is often its most prominent feature in UltraViolet views such as this one.
In this image, Cassini looks down on the North Pole of Titan and, although this view is centered on the Leading Hemisphere of the moon, the Lit Terrain seen here is mostly on the opposite, Trailing Hemisphere of the moon.
The image was taken with the Cassini Spacecraft narrow-angle camera on June 19, 2009 using a spectral filter sensitive to wavelengths of UltraViolet Light centered at 338 nanometers. The view was obtained at a distance of approx. 1,3 MKM (about 808.000 miles) from Titan and at a Phase Angle of 141°.
Image scale is 8 Km (about 5 miles) per pixel".MareKromium
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Titan-PIA11622-a.jpgTitan's Atmospheric Layers (Natural Colors; credits: Lunexit)55 visitenessun commentoMareKromium
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Titan-N00143762-N00143780.gifOverlap (GIF-Movie; credits: Dr G. Barca)55 visitenessun commentoMareKromium
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Titan_and_Dione-EB-LXTT-1.jpgFading in the Background... (Natural Colors; credits: Elisabetta Bonora - Lunexit Team)55 visitenessun commentoMareKromium
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Titan-W00064419-421-EB-LXTT.jpgTitan (Natural Colors; credits for the additional process. and color.: Elisabetta Bonora - Lunexit Team)55 visitenessun commentoMareKromium
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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...
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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".
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