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| Risultati della ricerca nelle immagini - "Layers" |
030-Mars-17-PIA09225_fig1.jpgThe "Lower Boundary" of the Icy Layers Covering Mars' South Polar Region (Map 2)61 visiteThis map shows the topography of the South Polar Region of Mars, including topography buried by thick deposits of icy material. The map is a combination of surface elevation data acquired by the Mars Orbiter Laser Altimeter aboard NASA's Mars Global Surveyor orbiter, and subsurface elevation data acquired by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) aboard the European Space Agency's Mars Express orbiter.
The black line shows the boundary of the South Polar Layered Deposits, an ice-rich geologic unit that was probed by MARSIS. Elevation values within the black outline, as measured by MARSIS, show the topography at the boundary between the layered deposits and the underlying material, an interface known as the "bed" of the deposits. The elevation of the terrain is shown by colors, with purple and blue representing the lowest areas, and orange and red the highest. The total range of elevation shown is about 5 Km.
The radar data reveal previously undetected features of topography of the bed, including depressions as deep as 1 Km (0,6 miles) shown in purple in the near-polar region.
The boundary of the layered deposits was mapped by scientists from the U.S. Geological Survey. The dark circle in the upper center is the area poleward of 87 South Latitude, where MARSIS data cannot be collected.
The map covers an area of 1670 by 1800 Km (about 1035 by 1115 miles).
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031-Mars-18-PIA09226_fig1.jpgThe "Upper Surface" of the Icy Layers Covering Mars' South Polar Region (Map 3)52 visiteThis map shows the topography of the South Polar Region of Mars. The data were collected by the Mars Orbiter Laser Altimeter aboard NASA's Mars Global Surveyor orbiter between 1997 and 2001. The elevation of the terrain is shown by colors, with purple and blue representing the lowest areas, and orange and red the highest. The total range of elevation shown is about 5 Km. The black line shows the boundary of the South Polar Layered Deposits, an ice-rich geologic unit that was probed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) aboard the European Space Agency's Mars Express orbiter.
The radar data indicate that the deposit is more than 3,7 Km (about 2,3 miles) thick in places, and that the material consists of nearly pure water ice, with only a small component of dust. The MARSIS team also determined that the total volume of ice in the layered deposits is equivalent to a water layer 11 mt (36 feet) deep, if spread evenly across the Planet. The boundary of the Layered Deposits was mapped by scientists from the U.S. Geological Survey. The dark circle in the upper center is the area poleward of 87 South Latitude, where MARSIS data cannot be collected.
The image covers an area of 1670 by 1800 Km (about 1035 by 1115 miles).
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16-Lunar Alps_H_SEMG9R7X9DE.jpgThe Lunar Alps103 visiteOriginal caption:"The European Alps were formed over millions of years by slow-moving sections of Earths crust pushed together, squeezing the land to form a giant arc of upthrust mountains, but the Lunar Alps were formed in an instant. It is thought that the Moon collided with a huge object, such as an asteroid, 3850 million years ago. The collision formed a huge crater, about 1000 Km in diameter. This crater was later filled with basaltic lava, forming the dark circular basin known as Mare Imbrium (Sea of Rains). After the explosive collision, fragments, rocks and dust fell back to the surface. While there is considerable debate as to the actual mechanism which formed the concentric rings, it is agreed they are not 'fallback' material. Some scientists argue that the the impact caused the lower layers to act as a liquid and that the rings then 'froze' in place. A flood of lava covered the lower inner one, but the outer one remains as a series of arc-shaped mountain ranges.
In places these mountains rise over 3000 metres. Their inner walls are steep and well defined, but their outer slopes become more broken as elevation decreases away from the impact site. Early European astronomers named them after familiar mountain ranges, such as the Juras, the Apennines and the Alps.
Seen in this image, Vallis Alpes (Alpine Valley) is a spectacular feature that bisects the Montes Alpes range. This valley was discovered in 1727 by Francesco Bianchini. It extends 166 kilometres from Mare Imbrium, trending north-east to the edge of the Mare Frigoris (Sea of Cold). The valley is narrow at both ends and widens to about 10 kilometres across.
The valley floor is a flat, lava-flooded surface that has narrow sinous rille running down the middle. It is generally considered to be a 'graben', an area between two parallel faults which has dropped below the surrounding area. This is believed to have formed after the formation of the basin, but before the full maria lava flows. The rille corresponds to a lava tube formed in a later geological episode by high-speed and low viscosity magma.
"SMART-1 is studying the signature of violent processes that took place during the formation of these giant impact basins, as well as the sequence of late volcanic history over the lunar surface until 3000 million years ago, said ESAs SMART-1 Project Scientist Bernard Foing.
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36-Shackleton_Crater-AMI_EAE3_001775_00002_00020.jpgSchakleton Crater in natural colors56 visiteThe Advanced Moon Imaging Experiment Camera (AMIE) obtained this image on 13 January 2006 - close to the time of Lunar Southern Summer - from a distance of about 646 Km over the surface and with a ground resolution of 60 mt per pixel.
Shackleton crater lies at the Lunar South Pole (89,54 S. Lat. and 0 East Lng.) and has a diameter of approx. 19 Km.
SMART-1 monitored this area almost every orbit. This will allow to produce very high resolution maps of the area as well as illumination maps. The long shadows that surround the crater make it very hard to observe. The analysis of the data obtained allowed a very detailed map of its rim, surrounding ejectas and craters.
SMART-1 also made long repeated exposures to see inside the shadowed areas. The purpose was detecting the very weak reflected light from the crater rims, and therefore study the surface reflection properties (albedo) and its spectral variations (mineralogical composition). These properties could reveal patchy ice surface layers inside the crater.
On the 2-kilometre wide inner edge of the crater ridge, at times barely visible from Earth, astronomers using ground radio-telescopes have recently reported they were not able to detect a distinctive signature of thick deposits of ice in the area. Earlier measurements by NASA's Lunar Prospector reported of hydrogen enhancement over large shadowed areas.
"We still do not know if this hydrogen is due to enhanced trapping of solar wind, or to the water ice brought on the Moon by the bombardment of comets and asteroids," says Bernard Foing, ESA's SMART-1 Project Scientist. "These bodies may have deposited on the Moon patchy layers of ice filling about 1.5 percent of the areas in permanent shadow, down to one metre below the surface."
"We need to analyse all remote sensing data sets consistently. Future lander and rover missions to the Moon will help in the search and characterisation of lunar polar ice, both on the surface and below the subsurface," Foing continues. "In any case, one day we may even be able to simply combine the implanted hydrogen and the oxygen extracted from lunar rocks to produce clean water, like we do in laboratory experiments on Earth.
The crater is named after Ernest Shackleton (1874-1922), an explorer famous for his Antartic expeditions.
MareKromium
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40-Jacobi Crater.jpgJacobi Crater (HR)52 visiteThis HR image was taken by the advanced Moon Imaging Experiment (AMIE) on 18 March 2006 from a distance of about 578 Km from the Moon's surface, with a ground resolution of 52 mt per pixel. It shows part of crater Jacobi in the Moon's Southern Hemisphere. The western crater rim can be seen on the left edge of the image. The imaged area is centred at a Latitude of 56,5 South and a Longitude of 10,9 East, with a field of view of 27 Km. North is up.
Crater Jacobi itself is much larger than this image - 68 Km in diameter - with the imaged area only showing about 1/5th of the crater floor area. The crater is centred at a Latitude of 56,7 South and a Longitude of 11,4 East. The single prominent crater to the upper left of the image centre is Jacobi "W", with a diameter of only 7 Km.
Peculiar surface structure can be seen in the lower left part of the image, and indicates several heavily eroded big-sized craters.
SMART-1 resolution at high solar elevation angle allows for the detection of eroded structures buried under more recent layers, giving a window on the past evolution of the Moon.
The crater is named after the German mathematician Karl Gustav Jacob Jacobi (1804 - 1851), who worked on elliptic functions and was active in the field of celestial mechanics
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8-Venus_from_Venus_Express-VIRTIS_COB05_vis_397_b.jpgVenus, from Venus Express (natural colors)77 visiteCaption ESA originale:"Views of the Southern Hemisphere of Venus in visible and ultraviolet light show interesting atmospheric stripe-like structures.
Spotted for the first time by Mariner 10 in the 1970s, they may be due to the presence of dust and aerosols in the atmosphere, but their true nature is still unexplained. "Venus Express has the tools to investigate these structures in detail. Studies have already begun to dig into the properties of the complex wind fields on Venus, to understand the atmospheric dynamics on local and global scales".
Venus Express also made use for the first time ever from orbit of the so-called 'infrared windows' present in the atmosphere of Venus if observed at certain wavelengths, it is possible to detect thermal radiation leaking from the deepest atmospheric layers, revealing what lies beneath the dense cloud curtain situated at about 60 Km altitude".
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APOLLO 15 AS 15 84-11257 G-1.jpgAS 15-84-11257 - Layering?146 visiteOriginal caption:"123:19:35 MT. Rightward from AS 84-11256 with good overlap. Note the apparent layering in the formation just below center on the right. The mare surface is believed to have been built up in a series of relatively thin lava flows with some impact 'weathering' of each fresh surface before the next flow. A cross-section would show a series of thin, horizontal layers".
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APOLLO 15 AS 15-9328.jpgAS 15-9328 - Bessel Crater52 visiteOutcrops of layered rock are strikingly evident in the upper part of the far wall of the crater Bessel (17- Km diameter) in South-Central Mare Serenitatis. The outcrop is most evident where it forms shadows; however, the dark debris that streams downslope from the layered rock is visible even on parts of the crater wall where the Sun has washed out all details of relief. The outcrop is at a uniform distance below the crater rim, indicating that the strata are horizontal. Thus, Bessel furnishes convincing evidence that mare surfaces are underlain by dark layered rock. The dark rock is now known to be basalt that accumulated as successive flows or layers of lava.
Bessel is youthful enough that boulders are abundant on its rim and floor.
An anomalously high number of boulders is visible in and around the 750-m diameter crater (arrow) on the floor.
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APOLLO 16 AS 16-4531.jpgAS 16-4531 - Teophilus' "Peak"53 visiteA detailed view of part of the central peak complex of Theophilus. Central peaks are typical of most young, large impact craters on the Moon-and also of many manmade craters on Earth. From experimental data using controlled explosions, central peaks are known to consist of bedrock originally lying below the crater floor that, during the explosion, was uplifted, faulted, and folded by shock wave action. The irregular light-toned mountainous mass projecting above the floor of Theophilus is split into at least three enormous blocks separated by V-shaped structural valleys. Four or five circular craters without a prominent raised rim are located near or at the bases of the steep slopes. If these craters are endogenic vents rather than impact craters, their presence further suggests structural control along major fault planes. The planar walls of the northwest-trending valley contrast with other sloping surfaces of the central peak complex. They are steeper and, except for a few outcrops of protruding bedrock, are marked by linear grooves not unlike slickensides on many fault planes on Earth. Rock chutes do not seem to be a likely explanation for the grooves because there are no talus deposits or blocks at their lower ends. The debris cover is thin enough along the southern valley wall (top of picture) to show that the southern mountain block consists of layered rocks-at least five thick, light-toned layers alternate with thin, dark layers.
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A_Pair_of_Small_Pit_Craters_(PSP_009488_1745)-3.jpgCollapse Pit66 visiteThe ability to detect and explore Martian Caves is of intense interest to many disciplines in Planetary Science. Caves may expose entire sets of stratigraphic layers, providing windows into Mars' Geologic and Atmospheric histories.
Cave environments can also protect organic life from extremely harsh conditions on the Martian Surface, and may provide future human explorers with secure habitats. Accordingly, Caves are considered among the most promising locations to find preserved evidence of past or present microbial life.
Furthermore, the challenges associated with Mars Cave exploration may inspire a range new technologies, such as advanced robotics and target-specific landing capabilities.MareKromium
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Aeolian_Features-Yardangs-20080111a.jpgAshes and Sulphur all over Apollinaris Patera (Extremely Enhanced Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 157 visiteSe, per questo frame, la NASA sottolinea, per altro giustamente, l'aspetto legato ai "segni del vento" lasciati nei pressi dell'antico vulcano noto come Apollinaris Patera, noi preferiamo enfatizzare il "senso" di questa colorizzazione (forse un p psichedelica, ma non fantasiosa).
Ricordate le istantanee Apollo 17 che ritraevano, nei pressi del Cratere noto come "Shorty", delle sabbie e detriti arancio/rossastri e che tanto stupirono la Comunit Scientifica? Ebbene, quel "bizzarro" colore della superficie lunare era solo l'evidenza di una remota attivit vulcanica o di un, forse pi recente, outgassing. Qualunque fosse l'origine del fenomeno, tuttavia, la sua causa venne chiarita attraverso l'analisi dei campioni riportati a Terra.
Per ricordare:"...On Earth, orange or rust-colored rocks and soil around volcanic vents are often the result of literal rusting of iron by volcanic water vapor. If this was the cause of the orange soil at Shorty then, small amounts of volcanic gasses might still be present (on the Moon)...".
Ed anche su Marte, ovviamente. Le "parole magiche", poi (e soprattutto per Marte), sono "ruggine causata da vapore acqueo". Ora la domanda ovvia: perch continuare a soffermarsi sulla tracce di "Aeolian Activities" quando c' qualcosa - a nostro parere - di molto pi intrigante da indagare?
Qualcosa che se, sulla Luna, poteva avere senso solo se riferita ad un remoto passato, su Marte potrebbe significare moltissimo in proiezione attuale e futura? Pensateci bene: il fenomeno del "rusting" (e quindi dei colori rosso/arancio accesi, sia sulla Luna, sia sulla Terra e sia su Marte o altrove nel Sistema Solare) si risolve nell'ossidazione di elementi ferrosi (iron-based and iron-rich elements) a causa della presenza di acqua (in qualche forma).
Perch quindi ignorare il vapore acqueo (con la possibile "cappa di umidit" in perenne sospensione, come sostiene l'Amico Matteo Fagone) e parlare solo di "venti", di "yardangs", di "layers" e di tante altre cose certamente importanti e meravigliose, ma mai tanto importanti e meravigliose quanto l'eventuale - ed attuale - presenza di acqua sul Pianeta "Arrugginito"?
Ecco: alla fine, ben pi di Cydonia e dei possibili "Artifacts Marziani", questo il VERO "mistero"...MareKromium
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C-Phoenix-PolarTexture.jpgPossible Northern Scenarios (2) - Layers58 visitenessun commentoMareKromium
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