| Piú votate - A Tribute To Mars Global Surveyor |
Chaotic_Terrain-Aram_Chaos-R2200155-01.jpgThe "Many Faces" of Aram Chaos (2 - EDM n. 1 - Original NASA/MGS/MSSS b/w Frame)54 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"
(4 voti)
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Craters-Lyell_Crater-00.jpgLyell Crater's Gullies (Original NASA/MGS/MSSS b/w Frame)54 visiteCaption originale:"This MGS-MOC image shows a suite of Gullies on a Scarp in Lyell Crater".
Location near: 69,7° South Lat. and 14,0° West Long.
Image width: ~3 Km (~1,9 mi)
Illumination from: upper left
Season: Southern Summer
(4 voti)
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Craters-Terby_Crater-01.jpgThe Sedimentary Layers of Terby Crater (1 - Original NASA/MGS/MSSS b/w Frame)53 visiteOriginal caption:"This MGS-MOC image shows some of the light-toned, layered, Sedimentary Rock Outcrops in Northern Terby Crater. Terby is located along the North edge of Hellas Planitia. The Sedimentary Rocks might have been deposited in a greater, Hellas-filling sea — or not. Today, the rocks are partly covered by dark-toned Sediment and Debris".
Location near: 27,2° South Lat. and 285,3° West Long.
Image width: ~3 km (~1,9 mi)
Illumination from: upper left
Season: Southern Summer
(4 voti)
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North_Polar_Regions-Unusual_Landscape-MGS-1.jpgIndecipherable North Polar Landscape (Original NASA/MGS/MSSS b/w Frame)53 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
(4 voti)
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Volcanic_Features-Lava_or_Mud_Flows-00.jpgControversial Features of Zephyria Planum (Original NASA/MGS/MSSS b/w Frame)53 visiteOriginal caption:"This MGS-MOC image shows a portion of a shallow Channel carved in the Plains of the Zephyria Region of Mars. This feature might be the result of the passing of either extremely fluid Lava or, perhaps, Mud".
Location near: 5,1° North Lat. and 203,7° West Long.
Image width: ~3 Km (~1.9 mi)
Season: Northern Winter
(4 voti)
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Meridiani_Planum_Region-PIA03650~0.jpgUnusual Landform in Meridiani Planum (Original NASA/MGS/MSSS b/w Frame)53 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.
(4 voti)
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Isidis_Planitia.jpgMartian "Cat-paw" print - Isidis Planitia (Original NASA-MGS-MSSS b/w Frame) 61 visiteOriginal caption:"This MGS-MOC image shows a mesa in North-Eastern Isidis Planitia. The mesa might be a remnant of terrain that once more extensively covered the Region".
Location near: 20,3° North and 267,7° West
Image width: ~3 Km (~1,9 mi)
Illumination from: lower left
Season: Northern Winter
Nota: il titolo che abbiamo dato al frame è giustificato dalla formazione craterica visibile sulla mesa la quale ci ricorda, in maniera quasi perfetta, l'impronta di un felino sulla sabbia.
(4 voti)
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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".
(4 voti)
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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".
(4 voti)
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Craters-Eberswalde_Crater-2-PIA04293_fig2.jpgEberswalde Crater and Delta in HR54 visiteOriginal caption:"Additional images from MOC provide some context and show a nearby portion of the fossil delta's inverted channels at a spatial scale of 1,5 mt (about 5 feet) per pixel. The relative positions of these 3 images are indicated in a mosaic image of the entire delta - picture (1). The first MOC narrow angle images of some of the landforms in the delta were acquired in 2000, during the MGS primary mission, but those pictures did not show very well the unambiguous inverted channel forms. Not until the second Earth year of the orbiter's extended mission were the deltaic features recognized in MOC images obtained in March and June of 2002.
Following the initial observations in 2002, the MOC Team began a systematic effort to map the entire Eberswalde Crater delta. Most of this imaging required slewing the whole spacecraft in a technique called "roll only targeted observation" so that it pointed the camera toward the feature. In this way, the camera team was able to build up a mosaic of the delta much more quickly than would have been the case if the team had simply relied upon chance crossing of the delta by the orbiter's usual ground track. This technique was not employed during Mars Global Surveyor's primary mission, except in the search for Mars Polar Lander, but became a routine part of the tool kit during the extended mission".
(4 voti)
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Meridiani_Planum-Tepe-2005_09.jpg"Tepe" in Sinus Meridiani (Original NASA/MGS/MSSS b/w Frame)57 visiteOriginal caption:"This MGS-MOC image shows a lonely, light-toned Butte (----> collina "a ceppo") composed of Sedimentary Rock in Northern Sinus Meridiani. The dark landscape that surrounds the Butte was once covered by the same rocks that make up this lonely remnant".
Location near: 2,5° North Lat. and 4,2° West Long.
Image width: ~3 Km (~1,9 mi)
Illumination from: lower left
Season: Northern Autumn
(4 voti)
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Craters-Holden_Crater-4-M0302733.jpgHolden Crater floor near intersection with Uzboi Vallis56 visitenessun commento
(4 voti)
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