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NGC-4038_and_NGC-4039-0.jpgNGC 4038 and 4039 - The "Antennae Galaxies"56 visite"...Ars longa, Vita brevis (est)..."
(Seneca)
"...La via dell'Arte (intesa come Scienza e Conoscenza) è eterna; la Vita (invece) è breve..."
Nota: tutta la Vita di un Uomo che si dedichi alle Arti ed alla Scienza non basta perchè egli possa svolgere la sua opera ed il suo pensiero per intero. Come Faust cade sul libro non finito, altri lo riprenderà per continuarlo e quindi seguirà la stessa fine e così via...ad infinitum.
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Corvus.jpgCorvus56 visite"...Conscia Mens, recti famae mendacia ridet..."
(Ovidio)
"...La Coscienza dell'Uomo onesto ride delle menzogne (proprie) della fama..."
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NGC-4038.jpgNGC 4038 - The "Antennae Galaxies"56 visite"...la Gloria è solo un effimero dono degli Dei..."
(dal film "Patton")
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TRA_000825_2665_IRB-01.jpgNorth Polar Layers (2)56 visiteNOTA:
This color images cover only the center swath of the full image, and is composed of images acquired through infrared, red, and blue-green filters. The color has been enhanced to better show the subtle color differences.
It is NOT natural color or how it would appear to normal human vision.
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TRA_000830_1440_IRB-1.jpgNiger Vallis (1)56 visiteThis image shows a portion of the floor of Niger Vallis, an ancient Martian outflow channel. Niger Vallis originates on the flanks of the volcano Hadriaca Patera, and empties into the Hellas impact basin. Outflow channels are observed in many regions of the planet, and may have been carved by brief eruptions of liquid water from beneath the surface. Since Niger Vallis formed, impacts have cratered the channel floor, and fine-grained wind-blown debris has been transported across the surface, eroding and burying all but the freshest craters. The curved ridge in the scene may be the remnant of a large crater rim. At the high resolution of this image, a pattern of parallel dunes and ripples can be seen, as well as individual boulders as large as two meters across.
Image TRA_000830_1440 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on September 30, 2006. The full image shown below is centered at -35.5 degrees latitude, 92.1 degrees East longitude. The range to the target site was 255 km (159 miles). At this distance the image scale is 51 cm/pixel (with 2 x 2 binning) so objects ~153 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel and north is up. The image was taken at a local Mars time of 3:35 PM and the scene is illuminated from the west with a solar incidence angle of 77.5 degrees, thus the sun was about 12.5 degrees above the horizon. At a solar longitude of 113.8 degrees, the season on Mars is Northern Summer / Southern Winter.
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Tethys-PIA08291.jpgTethys56 visiteCaption NASA:"Tethys has a crater-saturated surface, where older, larger basins have been completely overprinted by newer, smaller impacts. This state is what scientists expect to see on a very old surface, where small impactors have struck more frequently than larger ones over several billion years. Larger impacts were more common events in the early history of the Solar System.
This view looks toward the Leading Hemisphere of Tethys (1.071 Km, or about 665 miles across). North is up. The great scar of Ithaca Chasma is seen at right.
The view was captured in visible light with the Cassini spacecraft narrow-angle camera on Sept. 25, 2006 at a distance of approx. 449.000 Km (such as about 279.000 miles) from Tethys and at a phase angle of 49°. Image scale is roughly 3 Km (about 2 miles) per pixel".
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TRA_000828_2495_IRB-1.jpgPolygonal Terrain (1)56 visiteA network of shallow surface troughs and fissures coalesce into polygonal patterns that are ubiquitous throughout this image. Polygonal patterned ground of this nature is quite common in permafrost regions of Earth, where seasonal thermal contraction of ice-cemented soil produces a honeycomb network of subsurface cracks. Cracks of this nature can also be produced by desiccation (mud cracks) or lava cooling (columnar joints), though typically on a smaller scale. The diameter of these martian polygons are dominantly 10-20 meters, analogous to terrestrial permafrost. The individual troughs are frequently only a couple of meters or less wide, and easily resolved at HiRISE resolution. Other characteristics, such as small ridges on either side of the troughs and the distribution of rocks in and around each polygon is also readily apparent. Small rocks and occasional larger boulders are also seen scattered throughout the image. Rocks protruding above the surface soil can be seen to cast shadows (solar illumination is from the lower left), which can aid in the determination of the rock's size and height. This image is located near an area under consideration as a landing site for the Mars Scout mission, Phoenix, planned for 2008. Examination of many factors including surface texture (roughness and morphology) and the size distribution of rocks will aid in final landing site selection.
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TRA_000840_2750_IRB-002.jpgChasma Boreale (2)56 visiteDifferent layers show very different degrees of roughness and pitting, although the texture within a layer is quite consistent. One of the layers even displays a texture of polygons 3 up to 10 mt across, normally associated with periglacial freeze-thaw processes on Earth. Layers of different texture, brightness, and appearance indicate differing physical properties, composition and exposure to surface environmental conditions at time of emplacement and/or erosion.
In this way, polar layers on Mars record a history of climate conditions as sequences of layers on Earth often do.
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TRA_000840_2750_IRB-003.jpgChasma Boreale (3)56 visiteImage TRA_000840_2750 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on September 30, 2006.
The image is centered at 84,7° North Latitude and 16,1° East Longitude. The range to the target site was 319 Km (about 199 miles). At this distance the image scale is 32 cm/pixel (with 1 x 1 binning) so objects ~96 cm across are resolved.
The image shown here has been map-projected to 25 cm/pixel and North is up. The image was taken at a local Mars time of 3:28 PM and the scene is illuminated from the West with a solar incidence angle of 68,1°, thus the Sun was about 21,9° above the horizon.
At a Solar Longitude of 114,2°, the season on Mars is Northern Summer / Southern Winter.
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TRA_000840_2750_IRB-005.jpgChasma Boreale (5)56 visitenessun commento
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TRA_000840_2750_IRB-007.jpgChasma Boreale (6)56 visitenessun commento
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TRA_000828_1805_IRB-01.jpgYardangs in Medusae Fossae (1)56 visiteThis series of 4 images covers a portion of an outcrop of the Medusae Fossae Formation, a series of light-toned terrains in the Martian Mid-Latitudes. The Medusae Fossae has been and remains one of the most enigmatic features on Mars. The unit is characterized by wind-sculpted landforms, most notably eroded ridges known as yardangs. The composition of the Medusae Fossae is not known, but candidates include indurated (hardened) volcanic ash or remnants of dust-ice mixtures that formed in a different Martian climate. This HiRISE image reveals new details of the Medusae Fossae.
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