| Risultati della ricerca nelle immagini - "Vallis" |
021-The Moon from Clem-Aristachus-PIA00090.jpg042 - Aristarchus Crater (false colors)54 visiteThe Aristarchus region is one of the most diverse and interesting areas on the Moon. About 500 Clementine images acquired through three spectral filters (415, 750, and 1000 nm) were processed and combined into a multispectral mosaic of this region. Shown here is a color-ratio composite, in which the 750/415 ratio controls the red-channel brightness, it inverse (415/750) controls the blue, and the 750/1000 ratio controls the green. Color ratios serve to cancel out the dominant brightness variations and topographic shading, thus isolating the color differences related to composition or mineralogy. The Aristarchus plateau is a rectangular, elevated crustal block about 200 km across, surrounded by the vast mare lava plains of Oceanus Procellarum. Clementine altimetry shows that the plateau is a tilted slab sloping down to the northwest, that rises more than 2 km above Oceanus Procellarum on its southeastern margin. The plateau was probably uplifted, tilted, and fractured by the Imbrium basin impact, which also deposited hummocky ejecta on the plateau surface. The plateau has experienced intense volcanic activity, both effusive and explosive. It includes the densest concentration of lunar sinuous rilles, including the largest known, Vallis Schroteri, which is about 160 km long, up to 11 km wide, and 1 km deep. The rilles in this area begin at 'cobra-head' craters, which are the apparent vents for low-viscosity lavas that formed vents for 'dark mantling' deposit covering the plateau and nearby areas to the north and east. This dark mantling deposit probably consists primarily of iron-rich glass spheres (pyroclastics or cinders), and has a deep red color on this image. Rather than forming cinder cones as on Earth, the lower gravity and vacuum of the Moon allows the pyroclastics to travel much greater heights and distances, thus depositing an extensive regional blanket. The Aristarchus impact occurred relatively recently in geologic time, after the Copernicus impact but before the Tycho impact. The 42 km diameter crater and its ejecta are especially interesting because of its location on the uplifted southeastern corner of the Aristarchus plateau. As a result, the crater ejecta reveal two different stratigraphic sequences: that of the plateau to the northwest, and that of the portion of Oceanus Procellarum to the southwest. This asymmetry is apparent in the colors of the ejecta as seen in this image, which is reddish to the southeast, dominated by excavated mare lava, and bluish to the northwest, caused by the excavation of highland materials in the plateau. The extent of the continuous ejecta blanket also appears asymmetric: it extends about twice as far to the north and east than in other directions, approximately following the plateau margins. These ejecta lobes could be caused by an oblique impact from the southeast, or it may reflect the presence of the plateau during ejecta emplacement. Two dark blue spots in the center of Aristarchus represent tan especially interesting discovery. The infrared spectral properties measured by Clementine are consistent with a composition of almost pure anorthosite, the primitive rock type produced by the lunar magma ocean. This is the first discovery of a major exposure of anorthosite in this region of the Moon, well within the boundary of the hypothetical Procellarum basin. Don Wilhelms (Geologic History of the Moon, USGS Professional Paper, 1984) proposed that the giant Procellarum basin entirely removed the upper anorthositic crust from the north-central nearside of the Moon.
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024-Iani_Chaos_and_Ares_Valles.jpgMargaritifer Terra52 visiteCaption ESA originale:"This map shows that the Iani Chaos depression – 180 Km long and 200 Km wide – is connected to the beginning of Ares Vallis by a 100-Km wide Transition Zone, centred around 342,5º East and 3º North".
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033-The Moon from Clem-Aristarchus-3.jpg041 - Aristarchus and Vallis Schroteri54 visiteThe plateau of the Aristarchus Crater has experienced intense volcanic activity, both effusive and explosive.
It includes the densest concentration of Lunar "sinuous rilles" ("snake-like" valleys) including the largest known, Vallis Schroteri, which is about 160 km long, up to 11 km wide and 1 km deep.
The rilles in this area begin at cobra-head craters, which are the apparent vents for a dark mantling deposit covering the plateau and nearby areas to the North and East.
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14-Vallis Schroteri.jpgVallis Schroteri and Schiaparelli Crater66 visiteCaption NASA originale:"Lunar Orbiter 4 image showing Vallis Schroteri, the sinuous valley at the upper right. The large crater at the lower left is Schiaparelli, approximately 22 Km across. The very edge of Heredotus crater can be seen at the middle right of the frame, and the small crater towards the lower right is Herodotus-A. North is up (Lunar Orbiter 4, frame 157-H3)".
Location & Time Information
Date/Time (UT): 1967-05-22 T 18:01:16
Distance/Range (km): 2670
Central Latitude/Longitude (deg): +13.36/303.73
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15-T-SchroteriVallis.jpgSchroteri Valley, from Lunar Orbiter 5 (3D)83 visiteOriginal caption:"Stereoscopic view of a part of Schroter's Valley, the meandering depression running from the upper right to the lower left corner of the anaglyph. This rille is about 7 Km wide and up to 1300 m deep. Within its flat floor is a second, sinuous rille whose tightly packed meandor loops are about 200 m deeper. The ridge that is seen in the upper left portion of the photograph is about 1600 m higher than the plateau surface into which the Valley is cut".
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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 Earth’s 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 ESA’s SMART-1 Project Scientist Bernard Foing.
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APOLLO_15_AS_15-96-13063.JPGAS 15-96-13063 - EVA Floodlight near Herodotus "H" and Vallis Schroteri (2)56 visiteImage Collection: 70mm Hasselblad
Mission: 15
Magazine: 96
Magazine Letter: Q
Latitude: 26° North
Longitude: 51° West
Description: EVA FLOODLIGHT
Film Type: SO-368
Film Width: 70 mm
Film Color: color
Nota Lunexit: per che cosa è tanto "famosa" la Regione Lunare di Herodotus e della Schroteri Vallis?...MareKromium
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APOLLO_15_AS_15-96-13064.JPGAS 15-96-13064 - EVA Floodlight near Herodotus "H" and Vallis Schroteri (2)54 visiteImage Collection: 70mm Hasselblad
Mission: 15
Magazine: 96
Magazine Letter: Q
Latitude: 26° North
Longitude: 51° West
Description: EVA FLOODLIGHT
Film Type: SO-368
Film Width: 70 mm
Film Color: colorMareKromium
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Aeolian_Features-Dark_Windstreaks_in_Maja_Vallis-M0203557-00.jpgDark Windstreaks in Maja Vallis: The Area (Original NASA/MGS/MSSS b/w CTX Frame)53 visiteSi tratta di semplici Dark Wind-Streaks, oppure di residui ben visibili di un'intensa e recente attività vulcanica? Il detail mgnf Vi potrà essere di aiuto per tentare di dare una risposta, ma intanto potete già notare una cosa: i Wind-Streaks si formano, di regola, nell'area sottovento di un rilievo (tipo un cratere o un picco roccioso o, su piccola scala, dietro ad un sasso). In questo caso il rilievo che è causa del Wind-Streak è costituito dalla 'cresta' che vedete scorrere verticalmente lungo il frame (e che può essere costituita dal margine - o "rim" - esterno di una depressione non craterica ovvero proprio dal bordo di un antico - a giudicare da quanto vediamo nell'immagine - cratere.
E' indubitabile che il Wind-Streak copra l'intera lunghezza del rilievo, ma è pure evidente che tale 'striscia' NON è omogenea: essa è in parte chiara ed in parte scura. Ora, se provate ad elaborare l'immagine Voi stessi, noterete che le porzioni scure del Wind-Streak si trovano (quasi tutte) nell'area sottovento...
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Aeolian_Features-Dark_Windstreaks_in_Maja_Vallis-M0203557-01.jpgDark Windstreaks in Maja Vallis: The Streaks (Original NASA/MGS/MSSS b/w Frame - EDM)53 visite...situata in corrispondenza di minuscoli crateri o piccoli cracks del terreno (dobbiamo usare, in quest'ultimo caso, un pizzico di prudenza in più dato che non riusciamo a risolvere l'immagine in maniera tale da renderla in tutto e per tutto chiara).
L'ipotesi che avanziamo dopo aver svolto queste modeste annotazioni è ora decisamente ovvia: alcuni Wind-Streaks sono neri (o comunque molto scuri) perchè le polveri che li hanno formati erano 'sporche'.
Di cosa? Sporche di "fumo".
Vi abbiamo già proposto alcune immagini che potrebbero rappresentare delle colonne di fumo scuro le quali si innalzano dall'interno di piccoli crateri o cracks del suolo. Se, mentre questo fumo scuro fuoriesce, il vento comincia a soffiare, che cosa credete che vedremo, alla fine?
Il Wind-Streak che finirà con l'apparire sulla superficie di Marte, che colore avrà?
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Ares_Vallis-M1104220Det.gifAres Vallis115 visitenessun commento
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Channel-Bahram_Vallis-PIA13837-PCF-LXTT.jpgChannel in Bahram Vallis (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)253 visitenessun commentoMareKromium
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