| Ultimi arrivi - Mars Reconnaissance Orbiter (MRO) |
PSP_010888_1510_RED_abrowse.jpgClays and other "Hydrated Materials" in Sirenum Fossae Region (Natural Colors; credits: Lunar Explorer Italia)82 visitenessun commentoMareKromiumMag 04, 2009
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ESP_012435_2015_RED_abrowse.jpgBranched Features on the Floor of Antoniadi Crater (Natural Colors; credits: Lunar Explorer Italia)61 visiteThe dark branched features in the floor of Antoniadi Crater look like giant ferns, or fern casts. However, these ferns would be several miles in size and are composed of rough rocky materials.
A more likely hypothesis is that this represents a channel network that now stands in inverted relief. The channels may have been lined or filled by indurated materials, making the channel fill more resistant to erosion by the wind than surrounding materials. After probably billions of years of wind erosion the resistant channels are now relatively high-standing. The material between the branched ridges has a fracture pattern and color similar to deposits elsewhere on Mars that are known to be rich in hydrated minerals such as clays.
The inverted channels have short, stubby branches characteristic of formation by groundwater sapping. Spring water seeps into the channels and undercuts overlying layers which collapse, so the channels grow headward. These images tell the story of an ancient wet environment on Mars, where life could have been possible. Ancient Martian life was most likely to consist of microorganisms rather than giant tree ferns.
MareKromiumMag 04, 2009
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ESP_012725_2015_RED_abrowse.jpgBranched Features on the Floor of Antoniadi Crater (Natural Colors; credits: Lunar Explorer Italia)59 visitenessun commentoMareKromiumMag 04, 2009
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PSP_010505_2725_RED_abrowse.jpgNorth Polar Residual Cap (Natural Colors; credits: Lunar Explorer Italia)58 visitenessun commentoMareKromiumApr 27, 2009
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PSP_010454_1635_RED_abrowse~0.jpgCentral Uplift of Unnamed Impact Crater (Natural Colors; credits: Lunar Explorer Italia)74 visitenessun commentoMareKromiumApr 27, 2009
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PSP_010462_2505_RED_abrowse.jpgOlivine-rich Terrain in Vastitas Borealis (Natural Colors; credits: Lunar Explorer Italia)79 visitenessun commentoMareKromiumApr 27, 2009
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PSP_010428_1745_RED_abrowse.jpgThe Central Peak of Gale Crater (Natural Colors; credits: Lunar Explorer Italia)71 visitenessun commentoMareKromiumApr 27, 2009
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PSP_010449_1745_RED_abrowse.jpgPossible Hematite Deposits in West Candor Chasma (Natural Colors; credits: Lunar Explorer Italia)72 visitenessun commentoMareKromiumApr 27, 2009
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PSP_010525_2595_RED_abrowse.jpgLayering in North Polar Layered Deposit Trough (Natural Colors; credits: Lunar Explorer Italia)86 visitenessun commentoMareKromiumApr 27, 2009
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ESP_011664_2015_RED_abrowse-00.jpgAt the base of Olympus Mons... (ctx frame - Natural Colors; credits: Lunar Explorer Italia)61 visiteThis image is located at the foot of the largest volcano of the Solar System: Olympus Mons.
The entire scene is covered with a multitude of Lava Flows. Most of the Flows consisted of relatively sticky lava that froze after flowing for only a short distance (often less than 1 Km, or about 1/2 a mile). However, a few of the Flows were more fluid and actually drained out of their Channels, leaving Troughs with distinct levees. These “Channelized” Flows extend out of the HiRISE image so they must be at least several kilometers (a few miles) long.
In all likelihood, both the short and long Lava Flows have very similar chemical compositions.
Based on experience with Lava Flows on Earth, the Channelized Flows were probably fed by more vigorous eruptions. That is, the Lava Flow was fed so quickly that the lava traveled a long distance before it solidified. With the shorter flows, a slow dribble of lava froze before going more than the equivalent of a few city blocks.MareKromiumApr 25, 2009
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ESP_011664_2015_RED_abrowse-01.jpgAt the base of Olympus Mons... (edm - Natural Colors; credits: Lunar Explorer Italia)60 visiteThe Ridge with 2 Knobs in the center of this edm is of special interest. The Lava Flows radiate away from these Knobs, indicating that the Flows were fed from these points. However, based on experience with the current eruption of Kilauea Volcano in Hawaii, it seems that these Vents were fed by a Lava Tube.
Thus the magma first reached the Surface some distance away, then was transported through a Tube to this location. A blockage in the Tube would force the lava to burst out and erupt onto the Surface.MareKromiumApr 25, 2009
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ESP_012692_1810_RED_abrowse.jpgThe "Dusty" Summit of Pavonis Mons (Natural Colors; credits: Lunar Explorer Italia)60 visitePavonis Mons is one of the 3 giant Tharsis Montes Shield Volcanoes. Its Summit rises so far above the Surface that the Atmosphere is extremely thin, even for Mars.
Dust that reaches these heights (for example, during major Dust Storms) is hard to remove, so the upper parts of these Volcanoes are covered by vast deposits of dust. The dust is moved a little by the thin winds, producing ripples and other textures near the limit of HiRISE’s resolution. The fluffy, ripply surface looks “smudged” or out of focus, but by looking at some of the small impact craters you can see that the HiRISE camera is, indeed, properly focused. It’s the surface of Mars that is blurry!
Nota Lunexit: NO. A nostro parere NON è la Superficie di Marte che è "sfuocata" (blurry) e non è neppure la fotocamera dell'Orbiter che è "out of focus". Si tratta, come abbiamo già visto in passato (nelle immagini dei fly-by ravvicinati di alcune Lune Saturniane - Encelado su tutte) di un caso classico di "Sfuocatura da Movimento" (in altre parole: è un mero problema di lunghezza dell'esposizione - ivi: eccessiva -, data la vicinanza del target ripreso in rapporto alla velocità dell'Orbiter rispetto al medesimo). Curioso che i Ragazzi di Pasadena non ci abbiano pensato...
The impact craters also show that the dust is not a thin veneer. Instead, it is a thick coat, at least several meters deep. This mantling of dust hides the details of the Lava Flows and Vents, frustrating volcanologists but delighting those who study dust.
Mars Local Time: 15:23 (early afternoon)
Coord. (centered): 0,9° North Lat. and 246,8° East Long.
Spacecraft altitude: 254,1 Km (such as about 158,8 miles)
Original image scale range: 50,8 cm/pixel (with 1 x 1 binning) so objects ~1,53 mt across are resolved
Map projected scale: 50 cm/pixel
Map projection: EQUIRECTANGULAR
Emission Angle: 2,5°
Phase Angle: 52,4°
Solar Incidence Angle: 55° (meaning that the Sun is about 35° above the Local Horizon)
Solar Longitude: 244,7° (Northern Autumn)
Credits: NASA/JPL/University of Arizona
Additional process. and coloring: Lunar Explorer ItaliaMareKromiumApr 25, 2009
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