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Landslides-Navka_Region-PIA00262.jpgMagellan Probe: radio image of Landslides in Navka Region78 visiteCaption NASA originale:"The Magellan spacecraft has observed remnant landslide deposits apparently resulting from the collapse of volcanic structures. This Magellan radar image is centered about 25,4° south latitude and 308° east longitude in the southwestern Navka Region of Venus. The image shows a 17,4 Km (approx. 10,8 mile) diameter volcanic dome on the plains. The dome is approximately 1,86 Km (approx. 1,2 mile) in height and it has a slope of about 23°. The northwest and northeast flanks of the dome have collapsed to form landslides that have deposited debris on the plains. The image shows an area 110 Km (approx. 68 miles) across and 100 Km (approx. 62 miles) in length".
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Montes-Akna_Montes-PCF-LXTT.jpgAkna Montes (Natural Colors; credits: Lunar Explorer Italia)66 visitenessun commentoMareKromium
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Montes-Akna_Montes_-_Magellan.jpgMagellan Probe: radio image of Akna Montes118 visiteOltre il 98% della superficie del Pianeta venne ripresa con immagini ad altissima risoluzione (nell'ordine dei + o - 100 metri) e svariate aree vennero inquadrate più volte.
Furono scattate 4225 immagine SAR e, per gli amanti della tecnologia spaziale, possiamo dire che ogni orbita tipica (regolare) della Navicella copriva un'area (di Venere) lunga circa 17.000 Km e larga 20.
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North_Polar_Regions-Ishtar_Terra.jpgIshtar Terra73 visiteIshtar Terra: this is a topographic map made by Don P. Mitchell, from Venera and Magellan altimetry data.
It shows the continent-sized highlands of Ishtar Terra, near the North Pole of Venus.
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Ovda_Regio-PIA00218.jpgOvda Regio (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)54 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.MareKromium
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South_Polar_Region-InfraRed-1.jpgVortexes at the South Pole of Venus (infrared) - frame 154 visiteHigh velocity winds are known to spin westwards around the planet, and to take only four days to complete a rotation. This 'super-rotation', combined with the natural recycling of hot air in the atmosphere, would induce the formation of a vortex structure over each pole. But why two vortexes?
"We still know very little about the mechanisms by which the super-rotation and the polar vortexes are linked," said Håkan Svedhem, ESA’s Venus Express Project Scientist. "Also, we are still not able to explain why the global atmospheric circulation of the planet results in a double and not single vortex formation at the poles. However the mission is just at the beginning and it's doing fine; we expect this and many other long-standing mysteries to be addressed and possibly solved by Venus Express" he added. Atmospheric vortexes are very complex structures that are very difficult to model, even on Earth.
Thanks to these first pictures, it has also been possible to observe the presence of a collar of cold air around the vortex structure, possibly due to the recycling of cold air downwards.
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South_Polar_Region-InfraRed-2.jpgVortexes at the South Pole of Venus (infrared) - frame 253 visiteThese 6 (4 in the previous frame plus 2 in this frame) different infrared images (in false colour) were taken by the VIRTIS on board ESA’s Venus Express spacecraft between 12 and 19 April 2006, during the first orbit, or ‘capture orbit’, around the Planet.
The images (taken at 5 microns) were obtained at six different time slots and different distances from Venus (top left - frame 1: 12 April, from 210.000 Km; top centre - frame 1: 13 April, from 280.000 Km; top right - frame 2: 14 April, from 315.000 Km; bottom left - frame 1:16 April, from 315.000 Km; bottom centre - frame 1: 17 April, from 270.000 Km; bottom right - frame 2: 19 April, from 190.000 Km), while the spacecraft moved along a long ellipse around the Planet.
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South_Polar_Regions-0.gifVenusian South Polar Vortex through Venus Express (1)53 visiteThis composite video sequence was obtained by the Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) on board ESA’s Venus Express.
The single images were taken from 7 to 11 April 2007 over 5 different orbits. In each orbit the images were collected over a time span of 8 hours and were separated by about half an hour. The average distance from the Planet was about 65.000 Km.
The Latitude of the observed area spans 50 to 90° South. The Longitude spans about 20 to 150° East.
The video shows details of the Planet’s South Pole in RGB colour. The data obtained at 1.7 microns is shown in blue, while those obtained at 3.8 microns is represented in red.
Using specific wavelengths (3.8 and 1.7 microns, respectively), the observations allowed the imaging of the day and night areas around the South Pole simultaneously, at different depths (at about 65 Km and below the cloud deck, respectively) simultaneously. The intersection between the polar atmospheric structures seen at different wavelengths is visible well, due to the optical properties of the clouds.
MareKromium
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South_Polar_Regions-1.gifVenusian South Polar Vortex through Venus Express (2)54 visiteThis composite video sequence was obtained by the Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) on board ESA’s Venus Express.
The single images were taken from 7 to 11 April 2007 over 5 different orbits. In each orbit the images were collected during a time span of 8 hours and were separated by about half an hour. The average distance from the Planet was about 65.000 Km.
The Latitude of the observed area spans from 90 to 50° South. The Longitude spans from about 20 to 150° East.
The video shows details of the Planet’s South Pole with edge-enhanced contrast.
Using specific wavelengths (3.8 and 1.7 microns, respectively), the observations allowed the imaging of the day and night areas around the South Pole simultaneously, at different depths (at about 65 Km and below the cloud deck, respectively) simultaneously. The intersection between the polar atmospheric structures seen at different wavelengths is visible in good detail, due to the optical properties of the clouds.MareKromium
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South_Polar_Regions-2.jpgHot vortex over Venus' South Pole59 visiteESA's Venus Express has returned the first-ever images of the hothouse Planet’s South Pole from a distance of 206.452 Km, showing surprisingly clear structures and unexpected detail. The images were taken on April 12, 2006, during the spacecraft’s initial capture orbit after successful arrival on the 11th.
Engineers have lost no time in switching on several of the instruments and yesterday the VMC (Venus Monitoring Camera) and VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) imaged, for the first time in space history, the Southern Hemisphere of Venus as the spacecraft passed below the Planet in an elliptical arc.
Scientists are especially intrigued by the dark vortex shown almost directly over the South Pole, a previously suspected but until now unconfirmed structure that corresponds to a similar cloud structure over the North Pole. “Just one day after arrival, we are already experiencing the hot, dynamic environment of Venus” said Dr Hakan Svedhem, Venus Express project scientist“.
“We will see much more detail at an unprecedented level as we get over 100 times better resolution as we get closer to Venus, and we expect to see these spiral structures evolve very quickly.”
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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".MareKromium
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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".MareKromium
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