| Piú votate - Mars Reconnaissance Orbiter (MRO) |
PSP_008100_1790_RED_abrowse.jpgLayered Rocks in Iani Chaos (MULTISPECTRUM; credits: Lunexit)70 visiteThis image shows rocks on the floor of Iani Chaos, a Region of collapsed and disorganized Terrain.
The Chaotic Terrains on Mars may have been the sources of floodwaters that carved the giant outflow channels. They typically contain irregular hills like the one in the center of this image. In some cases, they also have light-toned rocks exposed on the floors. The point of interest is to determine whether these rocks predate the chaos or formed after the collapse; however, the contacts may be obscured by later material mantling the ground.
The rocks here are light-toned, and have dark low patches which are likely a thin cover of wind-blown sand. At a coarse scale, linear features are also visible in the rock, likely reflecting aeolian (wind) erosion in a preferred direction. A variety of processes could have contributed to forming these rocks, from volcanic eruptions to lake deposition or accumulation of wind-blown sand.
Stepped layers occur in places, suggesting a repetitive process. This argues for an origin as aeolian or lake-bed sediments, since volcanic eruptions may be of variable strength.MareKromium
(1 voti)
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PSP_002620_1410_RED_browse-01.jpgGullies on the edge of Newton Basin (extra-detail mgnf)53 visiteThe gullies start near the top of the wall and can be traced across a break in slope partway down the wall (see here, 750 mt across). This break in slope occurs along the entire portion of the Crater wall in this image. The gullies appear shallower just above the break in slope, and deeper below the slope break.
This suggests that the fluid which eroded and carved out the wall materials forming the gullies, increased in velocity after the slope break, creating a deeper section of the gully.MareKromium
(1 voti)
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T-TRA_000862_1710_RED_CandorChasma_01.jpgCandor Chasma53 visiteThis HiRISE sub-image shows the steep slopes along wallrock in the eastern edge of West Candor Chasma. In general, the rocks in the upper part of the canyons are interpreted to be lava flows that cover the plains surrounding Valles Marineris, whereas the deeper material along the walls could be either more lava flows or megaregolith that resulted from numerous impact craters that disrupted the Martian surface during the first billion years after formation of the planet. Resistant material is visible in portions of the sub-image and HiRISE is able to resolve 1-2 meter size boulders shedding out of these resistant wallrock units. The bright and dark lineations seen in the right of the sub-image follow the slope of the wallrock (downslope is towards the top of the sub-image) and likely represent bright dust and dark sand that are sliding downslope. The large number of small impact craters visible along the slopes indicates that there isn't a large amount of material moving downslope recently because these craters would have been destroyed or buried.
(1 voti)
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PSP_001367_1620_RED_abrowse.jpgGratteri Crater (Natural Colors; credits: Lunexit)54 visitenessun commentoMareKromium
(6 voti)
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PSP_006567_2220_RED_abrowse-01.jpgFlooded terrain in Terra Sabaea (extra-detail mgnf - MULTISPECTRUM; credits: Lunexit)63 visiteThe smooth surfaces of the flows are punctuated by curved, subparallel fractures oriented transverse to the flow direction.
These cracks resemble crevasses in terrestrial glaciers and were formed when the brittle solid crust of the flow fractured as it was dragged downstream. Detailed images such as this will help determine the role ice may have played in these flows.MareKromium
(6 voti)
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Elysium_Planitia-Tra_000867_1875_red-00.jpgElysium Planitia (CTX Frame - False Colors)54 visiteA low, sinuous tectonic ridge ("wrinkle ridge") can be seen in the South-East (lower left) and a rough-textured flow (lava?) fills the North-West (upper right) part of the image. Terraces that may have been carved by floodwaters are visible on the Southeastern side of the contact between the wrinkle ridge and the flow.
On the Northwestern side of this contact, the flow itself has a banded appearance reminiscent of contour lines or bathtub rings. It may be that long ago, when the flow was mobile, its surface level dropped, leaving these bands as indicators of how high it once stood. Alternatively, the bands could be buried terraces draped by the rough-textured flow. Relatively straight and narrow dunes (about 10 mt wide) have marched across the surface of the flow, and a thin layer of light-toned dust blankets the region. A dark spot about 100 mt in diameter on the left side of the image is probably where a cluster of small impacts blew away the dust, revealing the darker shade of the underlying surface.MareKromium
(6 voti)
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ESP_018301_2505_RED_abrowse-00.jpgLouth Crater (CTX Frame- Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)66 visiteThis HiRISE image shows a large Ice Mound located in Louth Crater. At 70° North (in the Region of Vastitas Borealis), this is the lowest latitude permanent deposit of water ice on Mars.
The HiRISE image, taken in early Summer, shows details of the Mound and non-ice portions of the Crater Floor.
The Mound is characterized by rough textures and layering similar to features seen on the North Polar Layered Deposits near the Martian North Pole. Zooming in to an area in the South-Eastern part of the Mound (see the following EDMs), dark Sinuous Ridges appear.
These may be the crests of partially defrosted Dark Sand Dunes or perhaps some other feature that we do not understand.
This is the only area on Louth where these enigmatic Ridges are found.MareKromium
(5 voti)
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ESP_014167_1300_RED_abrowse.jpgExposures of Layered Rocks in Argyre Planitia (Natural Colors; credits: Lunexit)54 visitenessun commentoMareKromium
(5 voti)
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ESP_025680_1350-PCF-LXTT-01.jpgUnnamed Crater with "Pedestal" in Terra Cimmeria (EDM - Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)81 visiteMars Local Time: 15:08 (Early Afternoon)
Coord. (centered): 44,814° South Lat. and 264,976° East Long.
Spacecraft altitude: 247,7 Km (such as about 154,8 miles)
Original image scale range: 49,6 cm/pixel (with 2 x 2 binning) so objects ~ 1 mt and 49 cm across are resolved (with 4 x 4 binning)
Map projected scale: 50 cm/pixel
Map projection: EQUIRECTANGULAR
Emission Angle: 0,3°
Sun - Mars - MRO (or "Phase") Angle: 79,1°
Solar Incidence Angle: 79° (meaning that the Sun is about 11° above the Local Horizon)
Solar Longitude: 58,6° (Northern Spring/Southern Fall)
Credits: NASA/JPL/University of ArizonaMareKromium
(4 voti)
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PSP_006984_1840_RED_abrowse~0.jpgLayers in Gordii Dorsum (MULTISPECTRUM; credits: Lunexit)55 visiteThis image shows distinctive differences in the texture of the ground surface in an area of Mars called Gordii Dorsum.
The upper right part of the image contains many subparallel ridges. These ridges are geological features called yardangs (long irregular ridges carved by wind erosion). The lower half of the image is smoother and contains a few small knobs and ridges. This area of Mars contains extensive outcroppings of layered sedimentary rocks that may have formed by the accumulation of sand and dust either blown in by the wind, transported by water, or some combination of processes such as these.
The distinctive surface textures may be due to differences in the rock structure and formation process. Mapping differences in the surface textures such as these may help to reveal how these rocks formed and advance our understanding of the geologic history of Mars.MareKromium
(4 voti)
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PSP_006477_1745_RED_abrowse-00~0.jpgDD Tracks in Southern Schiaparelli Basin (context frame - False Colors; credits: Lunexit)54 visiteDust-Devils (DD) are vortices of wind that form when air rising from a warm surface encounters shear in the above atmosphere.
Martian Dust-Devils can attain gargantuan proportions, reaching the size of terrestrial tornadoes with plumes that tower up to 9 Km above the surface.
Dust-Devils play an important role in sustaining the aerosols that make up Mars’ Red Sky and in cleaning the Martian Surface after a Dust Storm.
Nota Lunexit: sono quindi i DD, secondo la NASA, la "causa maggiore" del Cielo Rosso di Marte? Interessante riflessioni ed interessante quesito: dunque il Cielo di Marte NON E', naturalmente, "rosso" o "arancio", ma è "tinto di rosso/arancio"!
Pensateci sopra...
MareKromium
(4 voti)
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PSP_009161_1450_RED-00.jpgLong Shadows over Ariadnes Colles (ctx frame- natural colors; credits: Lunexit)54 visiteAriadnes Colles is a labyrinth-like cluster of hills, mesas and knobs located near Terra Cimmeria, in the Southern Highlands of Mars.
This image, which covers a portion of that labyrinth, was acquired only a few Soles away from Winter Solstice.
Winter Solstice occurs in the shortest Sol of the year, when the Sun travels the lowest in the Martian sky, making shadows appear very long. These conditions are ideal to analyze modest relief features, that would pass unnoticed when illuminated from above but are highlighted when illuminated from the side.MareKromium
(4 voti)
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