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South_Polar_Vortex-00.jpgVenusian South Polar Vortex (1)55 visiteOriginal ESA caption:"On 20 April 2006, after its first 9-day, elongated orbit around Venus, ESA’s Venus Express started to get closer to the Planet, until it reached its final 24-hour long orbit on 7 May. During this time, and up to today, the spacecraft has been working relentlessly: the new data coming in are already providing first glimpses on planetary features never seen before.
If taking the first ever clear images of the double-eye vortex at Venus’ South Pole - imaged by Venus Express during its very first orbit - was already a first in the history of planetary exploration and a very pleasant surprise for the scientists, nobody could expect that the vortex had a structure even more complicated than possibly foreseen".
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South_Polar_Vortex-01.jpgVenusian South Polar Vortex (2)59 visiteOriginal ESA caption:"Infrared images taken by the Ultraviolet-Visible-Near-Infrared spectrometer (VIRTIS) on board the spacecraft, not only provided the first clear view of the vortex, but also gave a much closer insight into it when Venus Express flew over the South Pole at the end of May 2006.
VIRTIS is an instrument that can operate at different wavelengths. Each infrared wavelength provides a view of the Venusian atmosphere at a different altitude, like a 'cross-section'.
"When we looked at this gigantic vortex at different depths, we realised how much its shape is varying over altitude", said Pierre Drossart, VIRTIS co-Principal Investigator, from the Observatoire de Paris, France.
"It is like if we were looking at different structures, rather than a single one.
And the new data we have just started gathering and analysing reveal even stronger differences".
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South_Polar_Vortex-02.jpgVenusian South Polar Vortex (3)53 visiteOriginal ESA caption:"The reason why the morphology of the vortex varies so extensively along a 'vertical' line is still unexplained.
"This is why we are organizing a campaign to observe the South Polar Vortex, fully dedicated to solve this unexpected puzzle", said Giuseppe Piccioni, VIRTIS co-Principal Investigator.
"First we want to understand how the structure is organized - actually, with VIRTIS we are building a true 3D view of the vortex. Then we hope to be able to better understand what are the driving forces that shape it".
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Thermal_Map-ORB410_01_surf_comp_H1.jpgThermal Map of Venusian Surface (comparison ESA/NASA)54 visiteCaption ESA:"An unprocessed thermal map of the Venusian Surface obtained by VIRTIS on 5 June 2007 (left) is compared here with a radar image of the same area obtained by NASA’s Magellan Spacecraft in the 1990s (right).
VIRTIS, the imaging spectrometer on board Venus Express, obtained this image at 1 micrometre, a wavelength that allows detection of radiation originating from the surface. The imaged region is that which NASA’s MESSENGER flew over as it made its closest approach to the Planet.
Magellan’s radar imaging and altimetry maps made it possible to measure the elevation and the radio-optical properties of the surface. Venus Express’ VIRTIS is providing the first complete set of thermal maps of the surface of Venus.
Correlations between topographic and thermal data similar to the ones shown in this image-composite will allow the scientists to understand if the measured temperature of the surface depends only on the altitude – where higher altitudes simply corresponds to colder, temperatures such as on Earth – or if it depends on the presence of previously undetected sources of heat such as active volcanoes".MareKromium
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Venus-Mariner_10.jpgVenus, from Mariner 10 (Natural Colors; credits: NASA/JPL)103 visitenessun commentoMareKromium
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Venus-PIA10123.jpgApproaching Venus53 visiteCaption NASA:"On Oct. 24, 2006, the MESSENGER Spacecraft came within 2990 Km (such as about 1860 miles) of Venus during its second planetary encounter.
Twenty days before closest approach to Venus the MESSENGER Dual Imaging System snapped pictures of the Planet from a distance of about 16,5 MKM (about 10,3 MMs). Despite the low resolution of the image on the left, one can see that Venus is shrouded in a thick blanket of clouds that hides its surface.
The picture on the right is the same image expanded 4 times, clearly showing the dense Venusian cloud cover".MareKromium
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Venus-PIA10124-PCF-LXTT-IPF.jpgApproaching Venus (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)78 visiteCaption NASA:"The Planet Venus is enshrouded by a Global Layer of Clouds that obscures its surface to the MESSENGER Dual Imaging System (MDIS) cameras. This single frame is part of a color sequence taken to help the MESSENGER team calibrate the camera in preparation for the spacecraft's first flyby of Mercury on January 14, 2008. Over the next several months the camera team will pore over the 614 images taken during this Venus encounter to ascertain color sensitivity and other optical properties of the instrument. These tasks address two key goals for the camera at Mercury: understanding surface color variations and their relation to compositional variations in the Crust, and ensuring accurate cartographic placement of features on Mercury's Surface.
Preliminary analysis of the Venus Fly-By images indicates that the cameras are healthy and will be ready for next January's close encounter with Mercury".
Nota Lunexit: questo NASA - MESSENGER color-frame è stato prima riportato sulla Scala dei Grigi, poi ingrandito, riprocessato e poi ricolorizzato in Colori Naturali Assoluti. Il risultato è un pò bizzarro, probabilmente poco realistico, ma sen'altro suggestivo. Giudicate Voi!MareKromium
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Venus-PIA10124.jpgVenus (natural colors; credits: NASA)54 visiteCaption NASA:"The Planet Venus is enshrouded by a global layer of clouds that obscures its surface to the MESSENGER Dual Imaging System (MDIS) cameras.
This single frame is part of a color sequence taken to help the MESSENGER team calibrate the camera in preparation for the spacecraft's first flyby of Mercury on January 14, 2008. Over the next several months the camera team will pore over the 614 images taken during this Venus encounter to ascertain color sensitivity and other optical properties of the instrument. These tasks address two key goals for the camera at Mercury: understanding surface color variations and their relation to compositional variations in the crust, and ensuring accurate cartographic placement of features on Mercury's surface.
Preliminary analysis of the Venus flyby images indicates that the cameras are healthy and will be ready for next January's close encounter with Mercury".MareKromium
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Venus-PIA10125.jpgFarewell to Venus53 visiteCaptio NASA:"After acquiring hundreds of HR images during close approach to Venus, the MESSENGER Spacecraft turned its wide-angle camera back to the Planet and acquired a departure sequence. These images provide a spectacular good-bye to the cloud-shrouded Planet while also providing valuable data to the camera calibration team. The MESSENGER Spacecraft was 60.688 Km (about 37.710 miles) from the Planet at the start of the sequence and 89.310 Km (approx. 55.495 miles) at the end. Initially, images were acquired at a rate of one of every 20', and then as Venus shrank the timing interval was increased to 60'.
The first image was taken on June 6, 2007, at 12:58 UTC (8:58 p.m. EDT on June 5), and the final image on June 7 at 02:18 UTC (10:18 p.m. EDT on June 6). During this 25 h, 20' period the Spacecraft traveled 833.234 Km (about 517.748 miles-more than twice the distance from the Earth to the Moon) with respect to Venus at an average speed of 9,13 Km-per-second (such as 5,67 miles-per-second).
These images represent the last view of Venus by the MESSENGER Spacecraft, but they also point toward the spacecraft's first encounter with Mercury in January 2008".MareKromium
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Venus-PIA12443.jpgVenus, overexposed and from VERY FAR AWAY...54 visiteImages from the latest Vulcanoid search are currently being transmitted to Earth, and one of those 256 images is shown here.
Vulcanoids are small rocky bodies that have been postulated to exist in orbits between Mercury and the Sun, though no such object has yet been detected.
MESSENGER has the unique opportunity to search for smaller and fainter Vulcanoids than has ever before been possible.
The best opportunities for MESSENGER to search for Vulcanoids are during perihelion passages, when the Spacecraft's orbit brings it closest to the Sun. MESSENGER has searched for Vulcanoids during three perihelion passages to date, in June 2008, in February 2009, and most recently in January 2010.
There will be another three perihelion passages in 2010, which will provide additional opportunities to continue the search.
MESSENGER images acquired to date have not revealed any Vulcanoids.
The bright object in the image here is Venus. For examining Venus, the image is over-exposed, but in the quest for very small, very faint objects, this type of image is just what is needed.MareKromium
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Venus-South Pole-Infrared-COB_combi_38b.jpgVortex over the South Pole of Venus (infrared vision)59 visiteDuring this first orbit – called the 'capture orbit' – some of the Venus Express instruments were used to perform the first observations at different distances from Venus, for a few hours per time on six different slots between 12 and 19 April 2006.
Amazing infrared, visible and ultraviolet images of the Venusian globe already reveal several atmospheric features of great interest.
The most striking of these is a huge, double-eye atmospheric vortex over the South Pole, not dissimilar from the equivalent structure present at the North Pole – the only one previously studied in some detail.
Only glimpses of the stormy atmospheric behaviour at the south pole were obtained by previous missions (Pioneer Venus and Mariner 10), but such a double-eye structure was never clearly seen before now.
This composite image shows six infrared views of Venus as seen by the Ultraviolet/Visible/Near-Infrared spectrometer (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 at different distances from Venus (top left: 12 April, from 210 000 kilometres; centre left: 13 April, from 280 000 kilometres; bottom left: 14 April, from 315 000 kilometres; top right: 16 April, from 315 000 kilometres; centre right: 17 April, from 270 000 kilometres; bottom right: 19 April, from 190 000 kilometres), while the spacecraft moved along a long ellipse around the planet.
The infrared radiation coming from Venus was converted in this reddish colour scheme. Thermal radiation comes from the lower atmosphere, (just above the cloud top, located at about 60 kilometres altitude). Solar radiation reflected by the upper atmospheric layers (roughly between 60 and 80 kilometres altitude) and thermal radiation from the layers below contribute to the brightest part of the image.
The south polar vortex structure is visible from different view points close to the centre of the images, mostly in the dark side.
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Venus-South Pole-PioneerVenus_South%20PoleVortex_H.jpgThe South Pole of Venus (again)60 visiteThese two images of Venus’s South Pole were taken by NASA’s Mariner 10 (during a Venus fly-by on its way to Mercury) and Pioneer Venus Missions during the early 1970s and 1980s, respectively.
The images provided the first glimpses about a stormy atmospheric behaviour at the south pole of the planet.
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