Mars Reconnaissance Orbiter (MRO)
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ESP_016022_1420_RED_abrowse-01.jpgThe Floor of Hellas Basin (EDM - Natural Colors; credits: NASA/JPL and Dr Paolo C. Fienga - Lunexit Team)58 visitenessun commentoMareKromium
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ESP_016032_2600_RED_abrowse-00.jpgNorthern Spring (CTX Frame - Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)54 visiteIn the Winter a layer of Carbon Dioxide (CO2) ice (such as Dry Ice) covers the North Polar Sand Dunes.
In the Spring the sublimation of the ice causes a host of uniquely Martian Phenomena.MareKromium
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ESP_016032_2600_RED_abrowse-01.jpgNorthern Spring (EDM - Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)54 visiteIn this EDM, Streaks of dark Basaltic Sand have been carried from below the ice layer to form Fan-shaped Deposits on top of the seasonal ice.
The similarity in the directions of the fans suggests that they formed at the same time, when the wind direction and speed was the same. They often form along the boundary between the dune and the Surface below the Dunes.MareKromium
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ESP_016032_2600_RED_abrowse-02.jpgNorthern Spring (EDM - Natural Colors; credits: NASA/JPL/Univ. of Arizona)54 visitenessun commentoMareKromium
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ESP_016036_1370_RED_abrowse-00.jpgDunes in Noachis Terra (CTX Frame - Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)54 visiteDunes of sand-sized materials have been trapped on the floors of many Martian Craters.
This is one example, from an Unnamed Crater located in Noachis Terra, West of the giant Hellas Impact Basin.
The most extensive Linear Dunefields known in the Solar System are on Saturn's largest moon Titan.
But Titan, as to Mars, has a very different environment and composition and so, at a meter-scale resolution (not available yet, unfortunately) the Titanian Dunes should look (better yet: they certainly ARE) very different from the Martian ones.MareKromium
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ESP_016036_1370_RED_abrowse-01.jpgDunes in Noachis Terra (EDM n.1 - Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)55 visiteThe Dunes here are linear, thought to be due to shifting wind directions.
In places, each Dune is remarkably similar to the adjacent one, including a reddish (or dust colored) band on the North-Eastern facing slopes.
Furthermore, very large Angular Boulders litter the floor between the Dunes.MareKromium
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ESP_016036_1370_RED_abrowse-02-PCF-LXTT.jpgDunes in Noachis Terra (EDM n.2 - Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)231 visitenessun commentoMareKromium
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ESP_016087_2595_RED_abrowse.jpgFrost-covered Dunes (Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)54 visiteDunes are often found on Crater Floors. In the Winter time, at high Northern Latitudes, the Terrain is covered by Carbon Dioxide Ice (Dry Ice - CO2 Ice). In the Spring, as this seasonal ice evaporates or sublimates, many unusual features - certainly unique to Mars - become visible.
On the Floor of this Crater, where there are no Dunes, the ice forms an uninterrupted layer. On the Dunes, however, Dark Streaks form as surface material from below the ice is mobilized and deposited on top of the ice. In some cases this mobile material probably slides down the steep face of the Dunes, while in other cases it may be literally blown out in a process of gas release similar to the one that we could obtain by removing a cork from a champagne bottle.
Nota Lunexit: ma i commenti NASA ai frames (non tutti, ma certamente alcuni, tipo questo) li fanno scrivere ai bambini ed alle bambine di Scuole Medie e/o Licei, per caso? Lo avevamo già stigmatizzato in passato ma, a volte, repetita juvant: alcuni commenti non solo sono, in sè, piuttosto naif (diciamo "ingenui", valà...) ed alquanto banali ma - e questa è la cosa più grave - essi contengono degli strafalcioni grammaticali (frequenti) e sintattici (meno di frequente) che fanno rabbrividire noi, poveri "ignoranti Italiani".
Bah...MareKromium
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ESP_016136_1525_RED_abrowse-00.jpgColourful Streaks (CTX Frame - Natural Colors; credits: NASA/JPL/Univ. of Arizona and Dr Paolo C. Fienga - Lunexit Team)54 visiteThis is an image of the Central Pit of an Unnamed Impact Crater located in the ancient Southern Highlands.
The Central Uplifts of large Impact Craters often collapse to form Pits on Mars, but they are still structural Uplifts and often expose deep Bedrock with diverse rock types which, like in this case (see the EDM that follows) may show a variety of colors.MareKromium
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ESP_016136_1525_RED_abrowse-01.jpgColourful Streaks (EDM - possible True Colors; credits: NASA/JPL/Univ. of Arizona and Dr Paolo C. Fienga - Lunexit Team)78 visiteIn this enhanced True Color EDM, we see colorful Streaks, where the bedrock is eroding, moving downhill a bit, then getting swept by the wind.MareKromium
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ESP_016160_2485_cut1.jpgPhoenix Lander in Springtime (Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)54 visiteWith early Spring at the Phoenix Landing Site comes the progressive sublimation of the Carbon Dioxide frost that has blanketed the Lander and surrounding terrain throughout the Winter.
During the long Polar-Winter Night, atmospheric CO2 freezes onto the Surface building up a layer of frost roughly 30 cm (about one foot) thick.
In the Spring this frost returns to the Atmosphere as gas (sublimates) over the course of several months. This image, part of a seasonal frost monitoring sequence, shows some areas of bare ground are beginning to be exposed. However, extensive frost patches remain in the topographic lows, such as the Troughs of the local polygonally patterned surface.
Even when the frost has completely sublimated, it must be underlined that the Dust deposited during the Winter could actually obscure (and "erase", in a view from atop) any and all the "Man-Made Features" that are still barely visible here (Backshell and Parachute, Heat-Shield and Lander).
The Parachute that is attached to the Backshell, in fact, is not apparent in this image, and we'll see if it reappears in later images.
Also gone are the dark halos around Lander, Backshell and Heat-Shield - again, this is due to seasonal frost and/or dust.
This and future images will help calibrate expectations for finding the Mars Polar Lander hardware which encountered Mars in 1999.MareKromium
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ESP_016173_2005_RED_abrowse-1.jpgSmall Shield Volcano with "Summit Caldera" (CTX Frame - Saturated and Enhanced Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team) 54 visitenessun commentoMareKromium
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