| Ultimi arrivi - Venus |
Lakshmi_Planum-PIA00249.jpgDanu Montes and Lakshmi Planum (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)53 visiteSouthwest Lakshmi Planum is bounded on the South by the Danu Montes.
Lakshmi Planum is an elevated plateau plain that is bounded on all sides by mountain chains. Here, the Danu Mountains have an angular fractured appearance. Chasms slice diagonally across the mountains in the lower left (South-West) corner of the image. Because of the steep slopes and the local relief of the mountains of several kilometers (2-3 miles, these fault-bounded troughs appear to zig-zag through the mountains when, in fact, they are probably straight if viewed from above.
The radar view provides a perspective that would place the viewer's eye to the right, 27° above the Horizon. Thus, slopes facing to the right can be seen completely, though dark, and slopes facing away to the left appear shortened, often seen only as thin bright lines. In the center of the image is a low volcanic dome (approx. 20 Km - about 12 miles - in diameter).
This type of volcanic feature frequently occurs on the low plains. This dome on the edge of Lakshmi is deformed and faulted where it has been affected by the forces that created the Danu mountains.
The image is approx. 75 Km (about 46 miles) on a side. The center is at 60° North Latitude and 324,5° East Longitude.MareKromiumGen 11, 2010
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Craters-Unnamed_Crater-PIA00468.jpgUnnamed (and heavily degraded) Crater (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)53 visiteDuring orbits 423 through 424 on 22 September 1990, Magellan imaged this Impact Crater that is located at Latitude 10,7° North and Longitude 340,7° East.
This Crater is shown as a representative of Venusian Craters that are of the proper diameter (about 15 Km) to be 'transitional' in their morphology between 'complex' and irregular'.
Complex Craters account for about 96% of all craters on Venus with diameters larger than about 15 Km; they are thought to have been formed by the impact of a large, more or less intact, mass of asteroidal material that has not been excessively effected during its passage through the dense Venusian Atmosphere.
Complex Craters are characterized by circular Rims, terraced Inner Wall Slopes, well developed Ejecta Deposits, and flat Floors with a Central Peak or Peak Ring.
Irregular Craters make up about 60% of the Craters with diameters less than about 15 Km. Irregular Craters are thought to form as the result of the impact of asteroidal projectiles that have been aerodynamically crushed and fragmented during their passage through the Atmosphere.
Irregular craters are characterized by irregular and/or discontinuous Rims and hummocky or multiple Floors.
The 'Transitional' Crater shown here has a somewhat circular Rim like larger Complex Craters, but has the hummocky Floor and asymmetric Ejecta characteristic of smaller Irregular Craters. MareKromiumGen 11, 2010
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Ovda_Regio-PIA00218.jpgOvda Regio (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)53 visiteThis Magellan image shows part of the interior of Ovda Regio, one of the large Highlands ringing the Equator of Venus.
Several tectonic events formed this complex block fractured terrain. An underlying fabric of Ridges and Valleys strikes N/E - S/W. These Ridges are spaced approx. 10 to 20 Km (such as about 6 to 12 miles) apart and may have been caused by shortening of the crust at right angles to this trend.
These structures are cut by thoroughgoing extension fractures trending N/W - S/E, suggesting a later episode of N/E - S/W extension. Lastly, the largest Valleys, particularly the about 20 Km (approx. 12 mile) wide one extending across the image, were filled with dark material, probably Lava.
The complex internal fabric of Ovda Regio attests to a long history of tectonic deformation.
This image, centered approx. at 1° South Lat. and 81° East Long., measures approx. 225 Km (about 140 miles) by approx. 150 (about 90 miles) and was acquired by Magellan in November 1990.MareKromiumDic 30, 2009
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Volcanoes-PIA00261.jpgVolcanoes in Guinevere Planitia (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)53 visiteThis image, with radar illumination from West to East, shows three unusual Volcanoes located in the Guinevere Planitia Lowland. At the center of the image is a large feature (approx. 50 Km or about31 miles in diameter) with an unusual shape; very round when viewed from above with steep slides and a flat top.
These Volcanoes are believed to be the result of relatively thick and sticky (viscous) Lava Flows that originated from a point source. Although a faint remnant of its original circular shape is preserved, the Northern Rim of this center Volcano has a steep Scarp.
The Scarp is probably the result of material that has slid away from the Volcano and subsequently has been covered by Lava Flows. This Volcano overlaps another feature to the South-West that is about 45 Km (approx. 28 miles) in diameter and disrupted by many fractures.
The South-Eastern Volcano (about 25 Km or approx. 15,5 miles in diameter) appears to be the highest of the three as its illuminated Western Edge has the brightest radar return. The scalloped Edges give this feature a bottlecap-like appearance. The highly scalloped Edges are probably the result of multiple material slides along the Volcano Margin.MareKromiumDic 29, 2009
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South_Polar_Regions-2008-04-03438_Composite_H.jpgThe Southern Hemisphere of Venus53 visiteCaption ESA:In this mosaic, InfraRed images taken at a wavelength of 5 micrometres (in red) are overlaid on UltraViolet images, taken at 0.365 micrometres.
The bright areas in the IR Images represent the temperatures at the cloud tops (dark regions denote lower temperatures). The oval feature that stands out in these images is the giant eye of a hurricane, or the Polar Vortex, at the Planet’s South Pole. Its centre is displaced from the South Pole and the structure measures about 2000 Km across, rotating around the Pole in about 2.5 days.
The Atmosphere rotates counterclockwise in this figure".MareKromiumSet 09, 2009
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Venus_in_UV-2008-04-03438_Figure_1_H.jpgVenus in UV53 visiteCaption ESA:"Venus Monitoring Camera image taken in the UltraViolet (0.365 micrometres), from a distance of about 30.000 Km. This picture shows numerous high-contrast features, caused by an unknown chemical in the clouds that absorbs UltraViolet light, creating the bright and dark zones.
With data from Venus Express, scientists have learnt that the Equatorial Areas on Venus that appear dark in UV Light are Regions of relatively high temperature, where intense convection brings up dark material from below. In contrast, the bright regions at Mid-Latitudes are areas where the temperature in the Atmosphere decreases with depth. The temperature reaches a minimum at the cloud tops suppressing vertical mixing.
This annulus of cold air, nicknamed the ‘cold collar’, appears as a bright band in the UV images".MareKromiumSet 09, 2009
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Venusian_Clouds_Altimetry-2008-04-03438_Figure_3_H.jpgAltimetry of Venus Clouds' Top54 visiteCaption ESA:"A Venus Monitoring Camera UltraViolet image with a superimposed colour mosaic, showing the altitude of the cloud tops.
The colour mosaic was derived from simultaneous pressure measurements by the Visible and Infrared Thermal Imaging Spectrometer".MareKromiumSet 09, 2009
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South_Polar_Regions-VI0310_00_5_H-PCF-LXTT.jpgVenus' South Polar Vortex (Absolute Natural Colors; credits for the additional process. and color.: Dr P>aolo C. Fienga - Lunexit Team)53 visiteCaption ESA:"This image, of the ‘Eye of the Hurricane’ on Venus was taken by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board Venus Express.
This picture shows a Region in the Venusian Atmosphere about 60 Km from the Surface, at a wavelength of about 5 micrometres. In this figure, the dipole assumes an eye-like shape and from here until the last image, it is possible to see how its shape evolves rapidly in a span of only 24 hours.
The yellow dot in the image indicates the location of the South Pole".MareKromiumAgo 10, 2009
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Craters-Mona_Lisa_Crater-PCF-LXTT-01.jpgMona Lisa Crater (Natural Colors; credits: Lunar Explorer Italia)56 visitenessun commentoMareKromiumMar 09, 2009
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Montes-Akna_Montes-PCF-LXTT.jpgAkna Montes (Natural Colors; credits: Lunar Explorer Italia)66 visitenessun commentoMareKromiumMar 09, 2009
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Craters-Adivar_Crater-1.jpgAdivar Crater (Natural Colors; credits: Lunar Explorer Italia)81 visitenessun commentoMareKromiumMar 09, 2009
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Volcanoes-Ammavaru-PCF-LXTT.jpgAmmavaru (Natural Colors; credits: Lunar Explorer Italia)60 visitenessun commentoMareKromiumMar 09, 2009
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