| Piú votate - Mars Reconnaissance Orbiter (MRO) |
PSP_004324_1060_RED_browse.jpgPolygons on South Polar Layered Deposits54 visiteThis image shows an exposure of south polar layered deposits, thought to record recent global climate changes on Mars.
The layers were probably laid down over the past few million years over a large area near the south pole, then eroded to show the layering visible in this image.
The layers appear brighter where their slopes are steeper and facing the Sun.
Within the brighter, steeper part of the layered deposits, a network of polygonal fractures is visible. The polygons outlined by the fractures are typically a few hundred meters (approx. 1000 feet) across, and traverse layer boundaries. Such polygonal fractures are seen on Earth in places where ground ice is present, and previous Mars orbiters have found evidence for abundant ground ice in the south polar region of Mars. So it is not surprising to see polygonal fractures here; what is unusual is that they cross layer boundaries, apparently unaffected by the changes in slope across them.
This suggests that the polygonal fractures formed after the scarp exposing the south polar layered deposits was formed by erosion. This indicates, possibly, that the scarp has been stable for some time, allowing the polygonal fractures to form.
MareKromium
(8 voti)
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PSP_004000_1560_RED_browse.jpgLayers in Eberswalde Crater54 visiteThis image covers a portion of Eberswalde Crater, revealing a possible delta-lake transition. Water flowed into the crater through a series of tributary channels to the west of the crater and after the water entered, it formed a distributive network and partly filled the crater to form a lake (Eberswalde Crater is approx. 70 Km wide and 1,2 Km deep).
The bright layers are part of the terminal scarp at the eastern edge of the delta. Some of the steeper slopes visible at the edge of the fan may be coarser-grained resistant channel ridges. The CRISM instrument on board the Mars Reconnaissance Orbiter has detected phyllosilicates (clays) in the bright layers. One of the ways clays form on Earth is when water erodes rock and makes fine particles which settle out of water; this often occurs in river deltas and lake beds.
The delta in Eberswalde Crater and the detection of phyllosilicates provides evidence for possible persistent aqueous activity on Mars.MareKromium
(8 voti)
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PSP_003222_1565_RED_browse.jpgProposed MSL Site in Eberswalde Crater56 visitenessun commentoMareKromium
(8 voti)
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PSP_002244_1720_red.jpgWhite Rock (Enhanced Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)54 visiteThis image shows a portion of a relatively bright landform named "White Rock" on the floor of Pollack Crater in the Sinus Sabaeus Region of Mars.
Data from the Mars Global Surveyor Thermal Emission Spectrometer (TES) indicates that this landform is not anomalously bright, relative to other bright Martian Regions. Further, the apparent brightness seen here is due to contrast with other materials on the crater floor.
Dunes and ripples are visible in the dark material between the bright ridges. Their orientations appear to be influenced by wind directionally channeled by the ridges. Material appears to have been shed from the white landform and deposited on the darker bedforms indicating that the light-toned outcrops break down into fine materials.
Its high albedo and location in a topographic basin have led to suggestions that White Rock is an erosional remnant of an ancient lacustrine evaporate deposit.
Other interpretations include an eroded accumulation of compacted or weakly cemented aeolian sediment.
(8 voti)
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Psp_001497_2480_red-00.jpgThe Northern Lakes: Lake "Ginny" (CTX Frame - False Colors)57 visiteQuando si sa dove guardare e che cosa cercare...Si finisce SEMPRE (o quasi...) con il trovare.
L'albedo del dettaglio che vedete in basso alla Vostra Dx è inconfondibile. Il detail-mgnf che abbiamo operato (e che vedrete nel prossimo quadro) è chiarissimo: c'è un nuovo Lago nelle Grandi Pianure Nordiche di Marte!
"Lake Ginny", questa volta (sempre con buona pace di IAU, NASA, ESA e di tutti gli altri Fenomeni che guardano, guardano, guardano...etc.).MareKromium
(8 voti)
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Psp_001401_1850_red-1.jpgThe "Bridges" of Arabia Terra (1) extra-detail mgnf80 visiteUn detail-mgnf che ci mostra con sconcertante chiarezza l'impossibilità che questi rilievi sìano il prodotto di azioni eoliche (anche complesse).
Alcuni Ricercatori suggeriscono un'origine artificiale per questi "ponti!" (o "tubi"); noi supponiamo, invece, una loro origine naturale, ma da investigarsi in un'ottica non geologica (o almeno NON SOLO geologica).
(8 voti)
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North_Polar_Scarp-Psp_001341_2650_red.jpgNorth Polar Scarp58 visitenessun commentoMareKromium
(8 voti)
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Northern_Plains-Psp_001380_2520_red-01.jpgAnother "Frozen Lake" in the Northern Plains? (2 - EDM - False Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)56 visitenessun commentoMareKromium
(8 voti)
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Hesperia_Planitia-TRA_000882_1595_RED-01.jpg"Fresh" Crater and unusual surface details in Hesperia Planitia (EDM - Extremely Enhanced and Saturated Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)55 visiteIl rilievo la cui albedo è tale da renderlo visibile anche in un'area ombreggiata (Sx del frame) non è risolvibile e, purtroppo, rimane inesplicabile; il rilievo posto a Dx, invece, lo risolviamo, applicando un ultra-detail mgnf, in un "boulder colonnare" (una surface feature spettacolare e molto rara, ma non necessariamente una Surface Anomaly in senso tecnico.
Semmai, ci domandiamo "da dove" possa provenire il boulder colonnare in oggetto e la nostra ipotesi è che potrebbe trattarsi di un ejecta.
(8 voti)
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Q-Q-PIA08030.jpgThe Atmosphere of Mars67 visiteThe Mars Climate Sounder, an instrument on NASA's Mars Reconnaissance Orbiter designed to monitor daily changes in the global atmosphere of Mars, made its first observations of Mars on March 24, 2006.
These tests were conducted to demonstrate that the instrument could, if needed, support the mission's aerobraking maneuvers (dips into the atmosphere to change the shape of the orbit) by providing hemisphere-scale coverage of atmospheric activity. The instrument scanned nine arrays of detectors four times across the entire disc of the planet, including the north pole, from an altitude of about 45,000 kilometers (28,000 miles). This is about 150 times farther away than the spacecraft will be during its main science phase. At this great range, the planet appears only 40 pixels wide, as suggested by the pixilation of the images. However, this is sufficient to identify regional dust storms in the lower atmosphere. Regional dust storms could perturb atmospheric densities at the higher altitudes (about 100 kilometers or 60 miles) where the orbiter will conduct more than 500 aerobraking passes during the next six months. Such storms are rare in the current season on Mars, early northern spring, and no large storms are present as the orbiter prepares for the start of aerobraking.
Each of the Mars Climate Sounder's arrays looks in a different wavelength band, and three of the resulting images are shown here. The view on the left is from data collected in a broad spectral band (wavelengths of 0.3 microns to 3 microns) for reflected sunlight. The view in the center is from data collected in the 12-micron thermal-infrared band. This band was chosen to sense infrared radiation from the surface when the atmosphere is clear and from dust clouds when it is not. The view on the right is from data collected at 15 microns, a longer-wavelength band still in the thermal-infrared part of the spectrum. At this wavelength, carbon dioxide, the main ingredient in Mars' atmosphere, hides the surface emission, and the thermal-infrared radiation comes only from the atmosphere.
The visible-and-near-infrared image (left) is bright where surface ice and atmospheric hazes reflect sunlight back to space. The view is of the northern half of Mars, with the north polar cap visible as the bright semicircle at upper left. The night half of the planet (lower left) is dark. The "terminator" boundary between the day side and night side of the planet cuts from lower left to upper right, through the polar area. During the science phase of the mission, after the spacecraft has shrunk its orbit to a nearly circular loop approximately 300 kilometers (186 miles) above the surface, these visible-and-near-infrared readings by the Mars Climate Sounder will track how the amount of solar energy reflected from Mars varies from place-to-place and season-to-season, particularly in the polar regions where absorbed sunlight vaporizes the seasonal carbon-dioxide ice.
The 12-micron image (center) indicates that heat is being emitted from both the day side and the night side of the planet. The polar cap is dark in this image because it is cold (minus 190 degrees Fahrenheit) and emits less heat than surrounding areas. During the science phase of the mission, the thermal-infrared readings at this wavelength by Mars Climate Sounder will be used to track dust and clouds in the atmosphere. In the current season on Mars, the atmosphere is relatively clear except for an equatorial belt of thin water-ice clouds present in the visible-and-near-infrared image, and so the 12-micron image is dominated by the infrared radiation from the surface on the relatively hot dayside (upper right).
The 15-micron image (right) indicates the temperatures of the atmosphere at an altitude of about 25 kilometers (15 miles), where there is not much temperature difference even between the night side and the day side of the planet. The polar atmosphere is colder, so it appears darker.
Once deployed in a low-altitude, nearly circular orbit next fall, the Mars Climate Sounder will systematically alternate views of the surface with views of the atmosphere above the limb (horizon) of the planet from the surface to an altitude of 80 kilometers (50 miles), with a vertical resolution of 5 kilometers (3 miles). In this way it will monitor atmospheric and surface changes through a full annual cycle to characterize the present climate of Mars.
(8 voti)
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ESP_026394_2160-PCF-LXTT-00.jpgHuge Dust Devil in Amazonis Planitia (CTX Frame - Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 93 visiteMars Local Time: 15:02 (early afternoon)
Coord. (centered): 35,5° North Lat. and 201,5° East Long.
Spacecraft altitude: 295,8 Km (such as about 184,9 miles)
Original image scale range: 31,9 cm/pixel (with 2 x 2 binning) so objects ~ 1 mt and 18 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: 40,4°
Solar Incidence Angle: 40° (meaning that the Sun is about 50° above the Local Horizon)
Solar Longitude: 83,0° (Northern Spring)
Credits: NASA/JPL/University of Arizona
Additional process. and coloring: Lunar Explorer ItaliaMareKromium
(7 voti)
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ESP_026394_2160-PCF-LXTT-01.jpgHuge Dust Devil in Amazonis Planitia (EDM - Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 90 visiteMars Local Time: 15:02 (early afternoon)
Coord. (centered): 35,5° North Lat. and 201,5° East Long.
Spacecraft altitude: 295,8 Km (such as about 184,9 miles)
Original image scale range: 31,9 cm/pixel (with 2 x 2 binning) so objects ~ 1 mt and 18 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: 40,4°
Solar Incidence Angle: 40° (meaning that the Sun is about 50° above the Local Horizon)
Solar Longitude: 83,0° (Northern Spring)
Credits: NASA/JPL/University of Arizona
Additional process. and coloring: Lunar Explorer ItaliaMareKromium
(7 voti)
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