| |
| Piú viste - Titan: The "Foggy" Moon |
Titan-Huygens_Landing_Site-11-PIA07229_modest.jpgHuygens' descent map (3) 60 visiteThe octagons indicate anticipated fields of view of panoramic mosaics of images taken by Huygens' descent imager and spectral radiometer instrument as the probe reaches certain altitudes during its descent. This map shows the footprints for mosaics to be assembled from 36 individual images at each altitude, with the field of view cut off at 75° from straight down although the actual images will extend all the way to the hazy horizon. Each mosaic made this way will be about 1.300 by 1.300 pixels. The largest octagon (in red) is about 1.120 Km across and represents the field of view for the mosaic of images taken at an altitude of 150 Km. From that height, individual pixels in the center of the image will be about 150 mts across, though haze between the ground and the camera at that height will likely degrade the resolution in those images. The location of the anticipated landing site is based on modeling of Titan's winds, and the actual landing site will be different if the actual winds experienced by Huygens during descent differ from this model.
|
|
Titan-Craters-Unnamed_Crater-PIA07368.jpgImpact Crater on Titan (radio-image)60 visiteCaption NASA originale:"This image shows a crater, approx. 60 Km in diameter, on the very eastern end of the radar image strip taken by the Cassini orbiter on its third close flyby of Titan on Feb. 15, 2005.
The appearance of the crater and the extremely bright (hence rough) blanket of material surrounding it is indicative of an origin by impact, in which a hypervelocity comet or asteroid, in this case, roughly 5-10 Km, in size, slammed into the surface of Titan. The bright surrounding blanket is debris, or ejecta, thrown out of the crater. The asymmetric appearance of this ejecta blanket could be an effect of "atmospheric winds" associated with the impact itself. Although clearly formed by impact, the feature lacks a central peak, suggesting that it has been eroded or otherwise modified after formation. Rainfall, wind erosion and softening of the solid material in which the crater formed are all possible processes that might have altered this impact feature".
|
|
Titan_and_Epimetheus-N00028722.jpgTitan and Epimetheus60 visitenessun commento
|
|
Titan-Regions-Shikoku_Facula-PIA08426.jpgThe Brightest Region of Titan: Shikoku Facula60 visiteCaption NASA originale:"This image of Saturn's moon Titan from the Synthetic Aperture Radar Instrument on the Cassini spacecraft shows Shikoku Facula, a Region that is bright in both radar and visible wavelengths. This radar image was taken on April 30, 2006.
A circular feature with a radar-dark interior, probably an impact crater, is seen near the top of the image and is about 35 Km (about 22 miles) in diameter.
Numerous linear dark features are seen running across the image, mostly on the right-hand side. These features were seen on other radar images and interpreted as dune fields. Bright, ridge-like features mainly on the lower half of the image may be topographically "High Regions" (qualcosa di simile alle HighLands della Scozia). Radar-dark, thin, sinuous features, which may be channels draining from the bright to the dark Regions, are seen below the circular feature".
|
|
Titan-Lakes-Unnamed_North_Polar_Lakes-04-PIA01943.jpgTitanian Northern Lakes (4)60 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".
|
|
Titan-Clouds-White_Clouds-PIA06112.jpgWhite Clouds60 visiteCaption NASA:"Shown here is a blowup of a region of Titan imaged on July 2, 2004. This image was taken at a distance of 339.000 Km (about 210.600 miles) and shows brightness variations on the surface of Titan and a bright field of clouds near the South Pole. The field of clouds is 450 Km (about 280 miles) across and is the about the size of Arizona. Features as small as 10 Km (a little more than 6 miles) can be discerned".
|
|
Titan-Island-PIA09180.jpgTitanian Sea and Islands in it60 visiteCaption NASA:"This radar image, obtained by Cassini's radar instrument during a near-polar flyby on Feb. 22, 2007, shows a big island smack in the middle of one of the larger lakes imaged on Saturn's moon Titan. This image offers further evidence that the largest lakes are at the highest latitudes.
The island is about 90 Km (approx. 62 miles) by 150 Km (approx. 93 miles) across, about the size of Kodiak Island in Alaska or the Big Island of Hawaii.
The island may actually be a peninsula connected by a bridge to a larger stretch of land. As you go farther down the image, several very small lakes begin to appear, which may be controlled by local topography.
This image was taken in synthetic aperture mode at 700 mt (2300 feet) resolution. North is toward the left. The image is centered at about 79° North Lat. and 310° West Long".
|
|
Titan-Regions-Hotei_Arcus_Region-PIA11839-3.jpgHotei Arcus in InfraRed (possible Natural Colors; credits: Lunar Explorer Italia)60 visitenessun commentoMareKromium
|
|
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)60 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
|
|
Titan-Craters-Unnamed_Crater-PIA07868_fig1.jpgTitan's most prominent Impact Crater59 visiteCaption NASA originale:"This 3-panel image shows one of Titan's most prominent impact craters in an infrared-wavelength image (left), radar image (center) and in the false-color image (right). The Cassini radar imaged this crater during Cassini's 3rd flyby of Titan, on Feb. 15, 2005. The Crater, located at 16° West, 11°North, is about 80 Km in diameter and is surrounded beyond that by a blanket of material thrown out of the crater during impact. In radar, brighter surfaces mean rougher terrains, or else terrains tilted toward the radar. The Crater has a dark floor and a small bright area in the center and it is surrounded by bright material, which has a very faint halo slightly darker than the surrounding dark material".
|
|
Titan-PIA07626.jpgThe "haze" of Titan59 visiteOriginal caption:"Looking back toward the sun brings out the thin haze that hovers 500 Km (310 miles) above Saturn's moon Titan.
The haze is composed of small particles whose diameter is comparable to the wavelength of light, which is ultraviolet light centered at 338 nnmts. Particles of this scale scatter sunlight most effectively in the direction opposite to the direction of sunlight itself.
Scientists are still trying to understand what processes produce this thin, high-altitude haze layer.
Picture data: North on Titan is up and tilted 10° to the right. The image was taken with the Cassini spacecraft narrow-angle camera on Sept. 24, 2005, at a distance of approx. 917.000 Km (about 570.000 miles) from Titan and at a Sun-Titan-spacecraft angle of 145°. Image scale is 5 Km (about 3 miles) per pixel".
|
|
Titan-IMG001935-br500.jpgTitan during Fly-By n. 9 (Original NASA/JPL/SSI RAW b/w Frame)59 visiteOriginal 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".
|
|
| 426 immagini su 36 pagina(e) |
|
|
|
|
|
13 | |
|
|
|
|
|
|
