| Piú viste - A Tribute To Mars Global Surveyor |
Craters-Eberswalde_Crater-4-PIA04293_fig3.jpgEberswalde Crater and Delta (Sub-meter-per-pixel cPROTO - detail mgnf)56 visiteOriginal caption:"Even with the roll only targeted observation technique, it took more than one Earth year to build up a complete mosaic of images of the delta. In the meantime, the first data showing the deltaic landforms were archived and released to the public and scientific community, long before the MOC Team's analysis and mosaic were complete. Some scientists began independent analyses of the landform at that time. The initial analysis and announcement of the feature was finally published in November 2003.
The Eberswalde delta provides the first clear, 'smoking gun' evidence that some valleys on Mars experienced persistent flow of a liquid with the physical properties of water over an extended period of time, as do rivers on Earth. In addition, because the delta today is "lithified" - that is, hardened to form rock - it provided the first unambiguous evidence that some martian sedimentary rocks were deposited in a liquid (presumably, water) environment. The presence of meandering channels, a cut-off meander, and crisscrossing channels at different elevations (one above the other), provided the clear geologic evidence for these interpretations".
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Craters-Eberswalde_Crater-5-PIA04293_fig3.jpgEberswalde Crater and Delta (Sub-meter-per-pixel cPROTO - detail mgnf)56 visiteOriginal caption:"After the sediments were deposited to form the delta, the material was further buried by other materials - probably sediments - that are no longer present. The entire package of buried material became cemented and hardened to form rock. Later, erosive processes - such as wind - stripped away the overlying rock, re-exposing the delta. Now preserved essentially as a fossil, the former floors of channels in the delta became inverted, to form ridges, by erosion. Channels can be inverted by erosion on both Earth and Mars. Usually this happens when the channel floor, or the material filling the channel, is harder to erode than the surrounding material into which the channel was cut. In some cases, the channels on Earth and Mars have been filled by lava to make them more resistant to erosion. In the case of Eberswalde, there are no lava flows; instead, the channel floors may have been rendered resistant to erosion either by being better-cemented than the surrounding material, or composed of coarser-grained sediment (such as sand and gravel as opposed to silt), or both".
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Meridiani_Planum_Region-PIA03650~0.jpgUnusual Landform in Meridiani Planum (Original NASA/MGS/MSSS b/w Frame)56 visiteOriginal caption:"This MGS-MOC image shows exposures of light-toned, layered, Sedimentary Rock among dark-surfaced plains in Northern Sinus Meridiani. The circular feature in the South-East (lower right) corner of the image is a wedding-cake-like tower of Sedimentary Rocks".
Location near: 2,9° North Lat. and 359,9° West Long.
Image width: width: ~3 Km (~1,9 mi)
Illumination from: lower left
Season: Northern Winter
Nota: una "torre", piuttosto regolare nelle forme e presumibilmente costituita da rocce sedimentarie stratificate ed erose dal vento (e se ci pensate solo un attimo non Vi sarà difficile realizzare quanto rara possa essere una simile configurazione) viene liquidata come "torre-tipo-torta-matrimoniale". Non fraintendeteci: lo sappiamo che la banalizzazione fa parte del più recente stile NASA ma, alle volte, dopo gli assurdi nomi dati alle rocce Marziane, dopo la Hamburger-Nebula e dopo la torre a torta, ci domandiamo quali sìano mai le reali idee ed impressioni dei Signori che si occupano di questa Materia.
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Craters-Airy_Crater-The_Prime_Meridian-1.JPGMars' Prime Meridian, such as: Longitude "0" (2 - Original NASA/MGS/MSSS CTX b/w Frame)56 visiteBeer and Mädler used a small circular feature, which they designated "a" as a reference point to determine the rotation period of Mars. The Italian astronomer G. V. Schiaparelli, in his 1877 map of Mars, used this feature as the 0 point of Longitude. It was subsequently named Sinus Meridiani ("Middle Bay") by Camille Flammarion.
When Mariner 9 mapped the Planet at about 1 Km (0,62 mile) resolution in 1972, an extensive control net of locations was computed by Merton Davies of the RAND Corporation. Davies designated a 0,5-Km-wide crater, subsequently named Airy-0 (within the large crater Airy in Sinus Meridiani) as the Longitude 0 point.
Airy-0 was imaged once by Mariner 9 and once by the Viking 1 orbiter in 1978, and these 2 images were the basis of the Martian Longitude System for the rest of the 20th Century. The MGS has attempted to take a picture of Airy-0 on every close overflight since the beginning of the mapping of Mars.
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North_Polar_Regions-Unusual_Landscape-MGS-1.jpgIndecipherable North Polar Landscape (Original NASA/MGS/MSSS b/w Frame)56 visiteOriginal caption:"This MGS-MOC image shows a slope on which layered materials are exposed by erosion in the North Polar Region of Mars. Wind streaks are also evident in this Summertime scene.
The layers that make up the material beneath the ice of the North Polar Residual Cap are typically considered to be a mixture of some amount of dust and ice, but the proportions of these constituents are not known".
Location near: 82,6° N; 298,1° W
Image width: ~3 Km (~1,9 mi)
Illumination from: lower left
Season: Northern Summer
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Clouds-South_Polar_Regions-PIA02182-1.jpgThick Clouds over the South Pole (Original NASA/MGS/MSSS b/w Frame)56 visiteCaption originale:"In this image the Martian Surface is completely hidden from view by thick clouds. The thickness of the clouds indicates the dust is a major component of the clouds. Images like this one can provide vital information about the atmosphere and climate of Mars today. This image was collected during late Summer near the South Pole".
Image information: VIS instrument;
Latitude: - 69,9° N;
Longitude: 235,3° E;
Resolution: 17 meter/pixel.
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Chaotic_Terrain-Aram_Chaos-R2200155-01.jpgThe "Many Faces" of Aram Chaos (2 - EDM n. 1 - Original NASA/MGS/MSSS b/w Frame)56 visiteIl Dr Skipper, per quanto attiene la Regione di Aram Chaos, ritiene di aver individuato (e secondo noi ha ragione) delle aree le quali ci mostrano la presenza di acque superficiali: prevalentemente si tratta di laghi e piccoli fiumi.
Egli dice che, a suo parere, queste aree rappresentano solo un modesto residuo di quelle che, un tempo, circolavano sulla superficie di Marte e che comuque anche queste acque stanno - di fatto - recedendo.
O meglio: esse stanno avviandosi a rinforzare quello che è già il sistema acquifero Marziano. Un sistema fatto di acque correnti e che, come già in molti credono (anche alla NASA...) è prevalentemente - diremmo al 95% - sotterraneo.
"I suspect that water poured into this Aram Chaos depression over a very long period of time saturating it and the subterranean ground systems under it with water. Then came along the current general long lasting dry period producing the remnants of an old very rough uneven lake bed bottom where shallow water still flows down elevated uneven portions of the chaotic terrain accumulating in the lowest catch basin areas you seen here. The cracked plate evidence seen in my first image in the right split screen in the southern part of Aram Chaos is probably washed in and compacted bottom old lake bed sediment collections in more elevated terrain there that has eventually drained dry into the lower areas and the sediment has cracked like great dry mud flats in the process"
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Chaotic_Terrain-Aram_Chaos-R2200155-09.jpgThe "Many Faces" of Aram Chaos (10 - EDM n. 9 - Original NASA/MGS/MSSS b/w Frame)56 visiteE dunque, alla fine, qual'è il "vero volto" di Aram Chaos, come del resto di Marte? Noi non lo sappiamo, ovviamente, però, come fa il Dr Skipper (che comunque stimiamo) e tanti altri Ricercatori, noi continuiamo a cercarlo...
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Clouds-South_Polar_Regions-PIA02694-1.jpgThick Clouds over the South Pole (Original NASA/MGS/MSSS b/w Frame)56 visiteThese clouds occurred near the South Polar Cap at the end of Southern Summer.
Image information: VIS instrument;
Latitude: - 80,3° North;
Longitude: 84,9° East;
Resolution: 17 meter/pixel.
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Craters-Buried_Crater-00.JPGUnder the Sand (Original NASA/MGS/MSSS b/w Frame)56 visiteCaption NASA originale:"This MGS-MOC image shows a partially-buried crater in the North Polar Region of Mars.
The circular feature is surrounded and partly overlain by some of the many, many sand dunes in the area. The steepest slopes on each dune — their "slip faces" — face toward the SouthEast, indicating that the dominant winds responsible for sand transport in this Region come from the NorthWest".
Location near: 76,0° North; 82,2° West
Image width: ~3 Km (~1,9 mi)
Illumination from: lower left
Season: Northern Spring
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Craters-Unnamed_Fresh_Crater_in_Noctis_Labyrinthus-MGS.jpgFresh Crater (Original NASA/MGS/MSSS b/w Frame)56 visiteCaption NASA originale:"This MGS-MOC image shows a relatively Fresh Crater with dark, rayed Ejecta on an upland plain above one of the many depressions in the Eastern Labyrinthus Noctis Region. The presence of the dark rays emanating from the Crater suggests that the impact was a relatively recent event compared to other Craters of similar diameter in the scene. Over time, the dark Ejecta will fade and blend in with its surroundings, owing to settling of Dust from the Atmosphere".
Location near: 9,7° South Lat. and 94,8° West Long.
Image width: ~3 Km (~1,9 mi)
Illumination from: upper left
Season: Southern Summer
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Craters-Spallanzani_Crater-MGS-00.JPGLayered "Mesa" inside Spallanzani Crater (Original NASA/MGS/MSSS b/w Frame)56 visiteCaption NASA originale:"This MGS-MOC image shows a layered, light-toned Mesa among other Layered Materials exposed in a mound that covers much of the Floor of Spallanzani Crater".
Location near: 58,3° South Lat. and 273,9° West Long.
Image width: ~3 Km (~1,9 mi)
Illumination from: upper left
Season: Southern Summer
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