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Craters-Unnamed_Craters-Lakshmi_Region-PIA00477.jpgPossible Remnants of a Meteoroid in Lakshmi Region (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)55 visiteThis full resolution mosaiced image covers an area of approx. 100 by 120 Km (such as about 62 by 74 miles) and is located in the Lakshmi Region of Venus, at 47° North Latitude and 334° East Longitude.
Due to the dense Venusian Atmosphere, Primary Impact Craters of less than a 3 Km (a little less than 2 miles) diameter are nonexistent.
The dark circular region and associated central bright feature in this image are thought to be the remnants of a Meteoroid smaller than the size necessary to create an Impact Crater, and entering the Atmosphere at low velocity (approx. 350 meters/second.)
The central bright feature appears to be a cluster of small secondary impacts, ejecta and debris from the original meteor that broke up in the Atmosphere.
Even though most of the meteorite did not hit the Surface, the Atmospheric Shock wave could be great enough to modify the surrounding region. One explanation for this radar dark circular formation, called "Dark Margins", could be that the shock wave was energetic enough to pulverize the Surface (smooth surfaces generally appear radar dark).
Another explanation is that the Surface could be blanketed by a fine material that was formed by the original meteor's breakup through the Atmosphere.
More than half of the Impact Craters on Venus have associated Dark Margins, and most of these are prominently located left of center of the rater. This is another effect which could be caused by the extremely dense Atmosphere of Venus. MareKromium
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Craters-Stephania_Crater-PIA00475.jpgStephania Crater (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)55 visiteCrater Stephania is located at 51,3° Norh Latitude and 333,3° East Longitude in Northern Sedna Planitia.
With a diameter of about 11 Km (6,8 miles), Stephania is one of the smaller Craters on Venus.
Because many small meteoroids disintegrate during their passage through the dense Venusian atmosphere, there is an absence of craters smaller than 3 Km (approx. 1,9 miles) in diameter, and even craters smaller than 25 Km (15,5 miles) are relatively scarce.
The apron of ejected material suggests that the impacting body made contact with the Surface from an oblique angle. Upon closer observation it is possible to delineate secondary craters, impact scars from blocks ejected from the primary crater.
A feature associated with this and many other Venusian Craters is a radar-dark halo.
Since dark radar return signifies a smooth surface, it has been hypothesized that an intense shock wave removed or pulverized previously rough surface material or that a blanket of fine material was deposited during or after the impact.MareKromium
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Volcanoes-Sacajawea_Patera-PIA00485.jpgSacajawea Patera (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)55 visiteThis Magellan image reveals Sacajawea Patera, a large, elongate caldera located in Western Ishtar Terra on the smooth plateau of Lakshmi Planum.
The image is centered at 64,5° North Latitude and 337° East Longitude. It is approximately 420 Km (about 252 miles) wide at the base.
Sacajawea is a depression approximately 1-2 Km (0,6-1,2 miles) deep and abo 120 by 215 Km (approx. 74 by 133 miles) in diameter; it is elongate in a S/W-N/E direction.
The depression is bounded by a zone of circumferential curvilinear structures interpreted to be Graben and Fault Scarps. These structures are spaced 0,5-4 Km (0,3-2,5 miles) apart, are 0,6-4 Km (0,4-2,5 miles) in width and up to 100 Km (approx. 62 miles) in length.
Extending up to approximately 140 Km (about 87 miles) in length from the South/East of the Patera, is a system of linear structures thought to represent a flanking rift zone along which the lateral injection and eruption of magma may have occurred.
A shield edifice of approx. 12 Km (about 7 miles) in diameter with a prominent Central Pit, lies along the trend of one of these features.
The Impact crater Zlata, approx. 6 Km (a little less than 4 miles) in diameter is located within the zone of Graben to the N/W of the Patera.
Few flow features are observed in association with Sacajawea, possibly due to age and state of degradation of the flows.
Mottled bright deposits of about 4 to 20 Km (such as 2,5 up to approx. 12 miles) in width are located near the periphery and in the center of the Patera Floor, within local topographic lows. Diffuse patches of dark material approx. 40 Km (such as about 25 miles) in width are observed S/W of the Patera, superposed on portions of the surrounding Graben.
The formation of Sacajawea is thought to be related to the drainage and collapse of a large Magma Chamber. Gravitational relaxation may have caused the resultant Caldera to sag, producing the numerous Faults and Graben that circumscribe the Patera.
Regions of complex, highly deformed tessera-like terrain are located North and East of the Patera and are seen in the upper portion of the image.MareKromium
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Craters-Isabella_Crater-PIA00480.jpgIsabella Crater (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)55 visiteCrater Isabella, with a diameter of approx. 175 Km (such as about 108 miles), seen in this MRI (Magellan Radar Image), is the second largest Impact Crater on Venus.
The feature is named in honor of the 15th Century Queen of Spain, Isabella of Castile. Located at 30° South Latitude and 204° East Longitude, the Crater has two extensive flow-like structures extending to the South and to the S/E.
The end of the Southern Flow partially surrounds a pre-existing 40 Km (approx. 25 mile) circular Volcanic Shield.
The South-Eastern Flow shows a complex pattern of Channels and Flow Lobes, and is overlain at its South-Eastern tip by deposits from a later approx. 20 Km (about 12 mile) diameter Impact Crater, Cohn (for Carola Cohn, Australian artist, 1892-1964).
The extensive Flows, unique to Venusian Impact Craters, are a continuing subject of study for a number of Planetary Scientists. It is thought that the Flows may consist of "Impact Melt", suc as rock melted by the intense heat released in the impact explosion. An alternate hypothesis invokes "Debris Flows", which may consist of clouds of hot gases and both melted and solid rock fragments that race across the landscape during the impact event.
That type of Emplacement Process is similar to that which occurs in violent eruptions on Earth, such as the 1991 Mount Pinatubo eruption in the Philippines.MareKromium
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Volcanic_Features-Lava_Flows-PIA00471.jpgLava Flows (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)55 visiteThis is a full resolution mosaic centered at 25° North Latitude and 351° East Longitude.
The Region is approximately 160 Km (100 miles) across. It shows a series of complex Lava Flows which emerge from the Northern Flank of Sif Mons, a large Southern Venusian Volcano.
Several of the Flows occupy narrow troughs formed by long fractures. A sequence of events that can be inferred from this image is the formation of the dark background Plains by eruptions of extremely fluid volcanic material, and the formation of the small Shield Volcanoes on the Plains' Surface that can be seen in the upper left part of the image.
Next, the Region was domed upward probably by heat from the interior of Venus that ultimately caused magmas to break out from the Surface near the Summit Regions forming the Sif volcanic structure and its associated flank eruptions which can be seen in this image.MareKromium
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Aegaeon-EB.gifIn the Aegaeon Sea... (GIF-Movie; creditgs: Elisabetta Bonora - Lunexit Team)55 visiteAegaeon, OR also Saturn LIII (being its provisional designation S/2008-S-1), is one of the very many moons of Saturn.
Its discovery was first announced by Dr Carolyn Porco, of the Cassini Imaging Science Team, on March 3, 2009, from observations taken on August, 15, 2008.
Aegaeon orbits within the bright segment of Saturn's G-Ring, and is likely a major source of the Ring itself. Debris knocked off the moon form a bright Arc near the Inner Edge of the G-Ring, which in turn spreads to form the rest of the Ring.
Aegaeon is "trapped" in the 7:6 co-rotation Eccentricity Resonance with Mimas. Aegaeon, Anthe and Methone therefore form a distinctive class of objects in the Saturn System: small moons in co-rotation Eccentricity Resonances with Mimas associated with (bright) "Arcs of Debris". Comparisons among these different Ring-Arc Systems reveal that Aegaeon’s orbit is closer to the exact Resonance than Anthe’s and Methone’s orbits are.
This could indicate that Aegaeon has undergone significant orbital evolution via its interactions with the other objects in its Arc's Segmet, which would be consistent with the evidence that Aegaeon’s mass is much smaller relative to the total mass in its Arc than Anthe’s and Methone’s masses are.
Assuming that Aegaeon has the same albedo as Pallene, his size is estimated to be about half a kilometer (approx. 500 mt) in diameter.
Aegaeon orbits Saturn at an average distance of about 167.500 Km from the Parent Planet (top of the Saturnian Clouds), in 0,80812 days (a little more than 19 hours), at an inclination of 0,001° to Saturn's Equator (being his Orbital Eccentricty equal to, 0,0002 - remember that the so-named "Mean Eccentricity" of an object is its Average Eccentricity, as resulting of perturbations over a given time period).
It is named after Aegaeon, one of the so-called "Hecatonchires" (Greek or "Centimani", in Latin). The Hecatonchires were 3 giants of incredible strength and ferocity, even superior to that of the Titans whom they helped overthrow.
Their name derives from the Greek words "hekaton" ---> "hundred" and "kheir" ---> "hand", and each one of them had a hundred hands and fifty heads.
Hesiod's Theogony (624, 639, 714, 734–35) reports that the 3 Hecatonchires became the guards of the gates of Tartarus (in Greek Mithology, it is a deep, gloomy place - a pit, or an abyss - used as a dungeon of torment and suffering that resides beneath the underworld).
In other words: an Hell deeper and darker than the "Traditional" Hell...MareKromium
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Prometheus-4311527815_3a8df4624e_o.jpgPrometheus adrift... (High-Def-3D - Possible Natural Colors; credits: Dr M. Faccin - Lunexit Team)55 visitenessun commentoMareKromium
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Prometheus-4311527645_dc29b5404a_o.jpgPrometheus adrift... (possible Natural Colors; credits: Dr M. Faccin - Lunexit Team)55 visitenessun commentoMareKromium
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Titan-EB.gifTitan (highly overexposed) with Startrails and a really bizarre "Light-Shadows' Effect" (GIF-Movie; credits: Elisabetta Bonora - Lunexit Team)55 visitenessun commentoMareKromium
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Titan-EB-MV.jpg"Methane View" of Titan (credits: Elisabetta Bonora)55 visitenessun commentoMareKromium
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Titan-W00062861-920.gifIn-Transit (GIF-Movie in Natural Colors; credits: Elisabetta Bonora)55 visiteChe dire? Uno SPETTACOLARE Gif-Movie realizzato in "Natural Colors" dalla nostra eccezionale Amica e Partner, Elisabetta Bonora.
Un Lavoro davvero fantastico che, se non altro "pubblicamente", la NASA NON HA ancora prodotto (rectius: NON HA VOLUTO PRODURRE).
E questo dato, sia detto chiaramente ed una volta per tutte, ci rende non solo orgogliosi, ma anche - e se non altro dal punto di vista della Tempestività e della (grandissima!) Qualità dei Lavori prodotti e pubblicati on-line - il Sito Scientifico/Divulgativo numero UNO in Europa (e, forse, uno dei Top Five al Mondo)!
Grazie a Tutti. MareKromium
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OPP-SOL2137-Pancam.jpgThe Beautiful Martian Paving - Sol 2116 (Image Mosaic - possible True Colors; credits: Dr G. Barca - Lunexit Team)55 visitenessun commentoMareKromium
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