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Venus-South_Polar_Vortex-12_VIRTIS_vortex_movie_H.gifThe restless South Pole of Venus (GIF-Movie - credits: ESA)70 visiteCaption ESA:"This video is composed of a set of images acquired by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board ESA’s Venus Express, during two observations slots in August 2007. The spacecraft was flying at a distance of about 65.000 Km from the Planet.
The video was obtained at 3.8-micrometre wavelength, allowing the instrument to see the cloud top thermal emission at an altitude of about 60-65 km.
The South Polar "Dipole", a complex atmospheric vortex-like feature situated over the South Pole of the Planet, can be clearly seen.
The change of the Polar Vortex shape in a time scale of a few hours is remarkably noticeable here"MareKromium
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Venus-South_Polar_Vortex-13_VIRTIS_vortex_movie_H.gifThe restless South Pole of Venus (GIF-Movie - credits: ESA)53 visiteCaption ESA:"This video is composed of a set of images acquired by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board ESA’s Venus Express, during two observations slots in August 2007. The spacecraft was flying at a distance of about 65.000 Km from the Planet.
The video was obtained at 3.8-micrometre wavelength, allowing the instrument to see the cloud top thermal emission at an altitude of about 60-65 Km.
The South Polar "Dipole", a complex atmospheric vortex-like feature situated over the South Pole of the Planet, can be clearly seen".MareKromium
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Venus-South_Pole-00.jpgThe South Pole of Venus (False Colors; credits: ESA)53 visiteCaption ESA:"This is a false-colour image taken with the Venus Monitoring Camera (VMC) on board ESA’s Venus Express.
It shows the full view of the Southern Hemisphere from Equator (Dx) to the Pole.
The South Pole is surrounded by a dark oval feature. Moving to the right, away from the Pole and towards the Equator, we see streaky clouds, a bright mid-latitude band and mottled clouds in the convective Sub-Solar Region.
This image was taken in the ultraviolet at 365 nanometres on 23 July 2007 as Venus Express was about 35.000 Km from the Surface of the Planet".MareKromium
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Venus-South_Pole-01.jpgThe South Pole of Venus (false colors; credits: ESA)53 visiteDa "NASA - Picture of the Day", del 26 Febbraio 2006:"Why did an acidic haze spread across Venus? The unusual clouds were discovered last July by ESA's robotic Venus Express Spacecraft currently orbiting Venus. The bright and smooth haze was found by Venus Express to be rich in Sulfuric Acid (H2SO4), created when an unknown process lifted Water Vapor and Sulphur Dioxide (SO2) from lower levels into Venus' upper Atmosphere.
There, sunlight broke these molecules apart and some of them recombined into the volatile Sulfuric Acid. Over the course of just a few days last July, the smooth acidic clouds spread from the South Pole of Venus across half the Planet.
The above false-color picture of Venus was taken last July 23rd (2007) in UV (Ultraviolet Light), and shows the unusual haze as relatively smooth regions across the image bottom. The cause of the dark streaks in the clouds is also not yet understood and is being researched".MareKromium
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Venus-South_Pole-02.jpgThe South Pole of Venus (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)53 visitenessun commentoMareKromium
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Venus-South_Pole-04.jpgVenus' South Pole (UV)60 visiteIn the 1st capture orbit, Venus Express will have 5 more opportunities for gathering data until reaching pericentre. These observations represent a great opportunity because, at apocentre, the full disc of Venus is fully visible for the spacecraft’s imagers. Such opportunities will not occur again during the nominal mission, starting on June, 4, 2006, when the range of distances from the Planet will be much smaller. In addition to VMC and VIRTIS, the spacecraft’s MAG (Venus Express Magnetometer) has been switched on for initial verification and is operating nominally. Together with the ASPERA (Analyser of Space Plasma and Energetic Atoms), the 2 instruments are expected to gather information about the unperturbed solar wind and the atmospheric escape processes on Venus, a Planet with no magnetic protection.
A series of further engine and thruster burns are planned to gradually reduce the apocentre during the following 16 orbital loops around the planet and the spacecraft is due to attain its final 24-hour polar orbit on 7 May, ranging from 66 000 to 250 kilometres above Venus.
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Venus-South_Pole-05.jpgVenus' South Pole (UV)63 visiteFalse-colour view imaged in ultraviolet of Venus' South pole captured by VMC - onboard Venus Express - on April, 12, 2006.
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Venus-Southern_Vortex-ESA-VE.jpgVenus' South Polar Vortex115 visiteCaption NASA:"What's happening over the South Pole of Venus?
To find out, scientists have been studying images taken by the robotic Venus Express spacecraft when it passes over the lower spin axis of Earth's overheated twin. Surprisingly, recent images from Venus Express do not confirm previous sightings of a double storm system there, but rather found a single unusual swirling cloud vortex.
In the above recently released image sequence taken in IR Light and digitally compressed, darker areas correspond to higher temperatures and hence lower regions of Venus' Atmosphere. Also illuminating are recently released movies, which show similarities between Venus' Southern Vortex and the Vortex that swirls over the South Pole of Saturn. Understanding the peculiar dynamics of why, at times, two Eddies (Eddy - plur. Eddies ---> vortice/i, mulinello/i) appear, while at other times a single peculiar Eddy appears, may give insight into how hurricanes evolve on Earth, and remain a topic of research for some time. In three months, the European Venus Express spacecraft will be joined around Venus by the Japanese Akatsuki satellite".MareKromium
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Venus-Volcano-NasaRubin_1600.jpgVenusian "Active" Volcano150 visiteCaption NASA Originale:"What would an erupting volcano on Venus look like? Evidence of currently active volcanoes on Venus was announced earlier this year with the unexplained warmth of regions thought to contain only ancient volcanoes.
Although large scale images of Venus have been taken with radar, thick sulfuric acid clouds would inhibit the taking of optical light vistas. Nevertheless, an artist's reconstruction of a Venusian volcano erupting is featured.
Volcanoes could play an important role in a life cycle on Venus as they could push chemical foods into the cooler upper atmosphere where hungry microbes might float. Pictured, the plume from an erupting volcano billows upwards, while a vast lava field covers part of the hot and cracked surface of Earth's overheated twin. The possibility of airborne microbial Venusians is certainly exciting, but currently controversial".MareKromium
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Venus_Clouds_-_Akatzuki_960.jpgVenusian Clouds145 visitenessun commentoMareKromium
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Venus_in_UV-2008-04-03438_Figure_1_H.jpgVenus in UV54 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".MareKromium
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Venusian_Atmosphere-Airglow_VIRTIS_Anticlockwise-00.jpgThe "Airglow" of Venus53 visiteNew infrared data is now available about Venus’ oxygen airglow – a phenomenon detectable on the night-side that makes the planet glow like a ‘space lantern’.
“The oxygen airglow was first discovered thanks to ground observations, and also observed by other missions to Venus such as the Russian Venera spacecraft and the US Pioneer Venus orbiter,” said Pierre Drossart, co-Principal Investigator on Venus Express’ VIRTIS instrument. “However, the global and detailed view we are getting thanks to Venus Express is truly unprecedented.”
The fluorescence of the airglow is produced when oxygen atoms present in the atmosphere ‘recombine’ into molecular oxygen (or ‘O2’) emitting light. Where does the oxygen come from?
“The oxygen in the atmosphere of Venus is a very rare element,” continued Drossart. At high altitudes in the atmosphere, on the day-side of Venus, the strong flux of ultraviolet radiation coming from the Sun ‘breaks’ the molecules of carbon dioxide (‘CO2’) present in large quantity in the atmosphere, liberating oxygen atoms. “These atoms are then transported by the so-called ‘sub-solar’ and ‘anti-solar’ atmospheric circulation towards the night side of the planet. Here the atoms migrate from the high atmosphere to a lower layer, called ‘mesosphere’, where they recombine into O2. By doing this, they emit light at specific wavelengths that can be observed through remote sensing from Earth and with Venus Express,” added Drossart.
The detection of the airglow, and the capability to follow its evolution in time, is extremely important for several reasons.
“First, we can use the distribution and motion of these fluorescent O2 ‘clouds’ to understand how the atmospheric layers below move and behave,” said Giuseppe Piccioni, the other co-Principal Investigator on VIRTIS. “In this sense, the O2 airglow is a real ‘tracer’ of the atmospheric dynamics on Venus.”
“Second, the analysis of this phenomenon will provide new clues on how its global atmospheric chemistry works – a very challenging task indeed, and still an open field of research,” continued Piccioni. “By calculating the speed at which this chemical ‘recombination’ takes place, we might be able – in the future – to understand if there are mechanisms that favour, or catalyze, this recombination, and learn more about the production and recombination of the other chemical species in the Venusian atmosphere.”
“Third, the observation of the oxygen airglow also allows to a better understanding of the global ‘energetic’ exchange between Venus’s mesosphere – at upper boundary of which the airglow is situated, with Venus’ thermosphere, an even higher layer directly influenced by the Sun.”
MareKromium
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