A Tribute To Mars Global Surveyor
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Dunes-Dark_Dunes-Noachis_Terra-PIA07351-00.jpgDark Dunes in Noachis Terra (Original NASA/JPL/MSSS b/w Frame)90 visiteCaption NASA originale:"This MGS-MOC image shows low albedo Sand Dunes on the floor of a crater in Southern Noachis Terra".
Location near: 52.5° South Lat. and 336.9° West Long.
Image width: ~~3.0 Km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
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Dunes-Dark_Dunes-Noachis_Terra-PIA07351-01.jpgDark Dunes in Noachis Terra (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)164 visiteCaption NASA originale:"This MGS-MOC image shows low albedo Sand Dunes on the Floor of an Unnameed Crater in Southern Noachis Terra".
Location near: 52.5° South Lat. and 336.9° West Long.
Image width: ~3,0 Km (~1,9 mi)
Illumination from: upper left
Season: Southern AutumnMareKromium
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Dunes-Noachis_Terra-00.jpgDark Dunes in Noachis Terra (Original NASA/JPL/MSSS b/w Frame)60 visiteCaption originale:"This MGS-MOC image shows Dark Sand Dunes and relatively small, light-toned, windblown Ripples on the Floor of an Unnamed Crater located in central Noachis Terra".
Location near: 50,0° South Lat. and 353,7° West Long.
Image width: ~3 Km (~1,9 mi)
Illumination from: upper left
Season: Southern Autumn
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Dunes-Noachis_Terra-01.jpgDark Dunes in Noachis Terra (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)154 visiteCaption originale:"This MGS-MOC image shows Dark Sand Dunes and relatively small, light-toned, windblown Ripples on the Floor of an Unnamed Crater located in central Noachis Terra".
Location near: 50,0° South Lat. and 353,7° West Long.
Image width: ~3 Km (~1,9 mi)
Illumination from: upper left
Season: Southern AutumnMareKromium
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Dunes-Ogygis_Region-MGS.jpgThe Dunes of Ogygis (Original NASA/MGS/MSSS b/w Frame)53 visiteCaption NASA originale:"This MGS-MOC image shows dark Sand Dunes, with a thin coating of Autumn Frost, in the Ogygis Regio, West of the Argyre Basin. The steepest Slopes on the Dunes (such as their "Slip Faces"), point toward the North-North/East (lower left), indicating that the Dominant Winds in the Region blow from the South-South/West (upper right)".
Location near: 50,4° South Lat. and 66,6° West Long.
Image width: ~3 Km (~1,9 mi)
Illumination from: upper left
Season: Southern Autumn
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Dunes-PIA07152-00.jpgDark Dunes and Yardangs inside Herschel Crater (Original NASA/MGS/MSSS b/w Frame)72 visiteImmagine ripresa dal Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) che ci mostra Dune di colore scuro, scolpite dal vento, che giacciono sul fondo del Cratere Herschel. La superficie di queste Dune sembra caratterizzarsi per il fatto che ci appaiono - anche da una notevole distanza... - consistenti fessure scavate al loro interno. Questo sta a significare che la sabbia che le forma NON è semplicemente "accatastata" (ma, granuloscopicamente parlando, "libera"), così come accade per la maggior parte delle Dune Terrestri! Questo fenomeno ci dice che la sabbia di queste Dune Marziane è "cementata e compatta", simile a roccia (fragile, ma pur sempre roccia), e l'azione costante dei venti, nel tempo, ha creato, su queste sabbie "indurite", delle particolari "aree erose" che sono conosciute come Yardangs. L'immagine copre un'area di circa 3 Km (1,9 miglia) la quale si trova vicino ai 15,6° di Latitudine Sud ed ai 229,0° di Longitudine Ovest. Il Sole illumina la scena dalla Sn, in alto.
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Dunes-PIA07152-01.jpgDark Dunes and Yardangs inside Herschel Crater (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)137 visitenessun commentoMareKromium
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Dunes-S20-00165d-_acquired_july_2006-_11-8-06-A.jpgDark Dunefield? (Original NASA/MGS/MSSS b/w Frame)68 visiteA nostro parere la "chiazza scura" che ci è stata segnalata dal Dr Barca e che caratterizza un'ampia porzione di questo frame non è un'ombra, bensì - dopo aver operato alcune comparazioni visive con altri frames similari - un "affioramento" di un qualche tipo (una "macchia" della superficie - simile ai "seeps" - che può essere indice della presenza di idrocarburi affioranti o, più spesso, dell'esposizione del suolo post evaporazione di ghiacci superfciali o sublimazione di ghiacci di CO2); da non escludersi la possibilità che si tratti di un reticolato - non risolvibile con questa bassa definizione - di Dark Dunes (insomma: un Dunefield a bassa albedo).
Le uniche ombre significative ed oggettivamente visibili dalle varie Sonde che orbitano attorno a Marte sono quelle di Deimos e Phobos, quando producono una Eclissi Solare. Tuttavia, esaminando qualche frames relativo ad Eclissi viste dall'orbita, si può notare che quando le lune di Marte proiettano ombra sulla Superficie del Pianeta, l'effetto visivo è molto diverso da quello che vediamo in questo frame.
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Dunes-S2200554sub-00.jpgMigrating Dunes (Original NASA/MGS/MSSS b/w Frame)108 visiteCaption NASA originale:"This MGS-MOC image shows a suite of dunes in one of the several North Polar Dune Fields. The bright surfaces adjacent to some of the dunes are patches of frost. These dunes spend much of the Autumn, Winter, and Spring seasons covered with CO2 frost. Only in late Spring and in Summer are the dark windblown sands fully exposed.
Over the course of the 9+ years of the MGS mission, the MOC team has sought evidence that sand dunes may be migrating downwind over time. However, no clear examples of the movement of a whole dune have been identified. On Earth, such movement is typically detectable in air photos of the smallest active dunes over periods of a few years. Owing to the fact that the North Polar Dunes spend much of each Martian Year under a cover of frost, perhaps these move much more slowly than their frost-free, terrestrial counterparts. The sand may also be somewhat cemented by ice or minerals, likewise preventing vigorous dune migration in the present environment.
This view covers an area approximately 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left. The dunes are located near 79.8°N, 127.1°W, and the picture was acquired on 11 September 2006.
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Dunes-S2200554sub-01.jpgMigrating Dunes (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team))163 visiteCaption NASA originale:"This MGS-MOC image shows a suite of dunes in one of the several North Polar Dune Fields. The bright surfaces adjacent to some of the dunes are patches of frost. These dunes spend much of the Autumn, Winter, and Spring seasons covered with CO2 frost. Only in late Spring and in Summer are the dark windblown sands fully exposed.
Over the course of the 9+ years of the MGS mission, the MOC team has sought evidence that sand dunes may be migrating downwind over time. However, no clear examples of the movement of a whole dune have been identified. On Earth, such movement is typically detectable in air photos of the smallest active dunes over periods of a few years. Owing to the fact that the North Polar Dunes spend much of each Martian Year under a cover of frost, perhaps these move much more slowly than their frost-free, terrestrial counterparts. The sand may also be somewhat cemented by ice or minerals, likewise preventing vigorous dune migration in the present environment.
This view covers an area approximately 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left. The dunes are located near 79.8°N, 127.1°W, and the picture was acquired on 11 September 2006.MareKromium
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Earth_and_Moon_from_Mars-00.jpgEarth and Moon from Mars90 visiteCaption originale:"This is the first image of Earth ever taken from another planet that actually shows our home as a planetary disk. Because Earth and the Moon are closer to the Sun than Mars, they exhibit phases, just as the Moon, Venus, and Mercury do when viewed from Earth. As seen from Mars by MGS on 8 May 2003, Earth and the Moon appeared in the evening sky. The MOC Earth/Moon image has been specially processed to allow both Earth (with an apparent magnitude of -2.5) and the much darker Moon (with an apparent magnitude of +0.9) to be visible together. The bright area at the top of the image of Earth is cloud cover over central and eastern North America. Below that, a darker area includes Central America and the Gulf of Mexico. The bright feature near the center-right of the crescent Earth consists of clouds over northern South America. The image also shows the Earth-facing hemisphere of the Moon, since the Moon was on the far side of Earth as viewed from Mars.The slightly lighter tone of the lower portion of the image of the Moon results from the large and conspicuous ray system associated with the crater Tycho.
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Earth_and_Moon_from_Mars-01.jpg"Us", from Mars (EDM)91 visitevedi il commento al frame precedente
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