| Ultimi arrivi - Venus |
Craters-Balch_Crater-1.jpgBalch Crater (Natural Colors; credits: Lunar Explorer Italia)53 visitenessun commentoMareKromiumMar 09, 2009
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Craters-Fossey_Crater-PCF-LXTT-01.jpgFossey Crater (Natural Colors; credits: Lunar Explorer Italia)53 visitenessun commentoMareKromiumMar 09, 2009
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Venusian_Surface-Venera_13-08.jpgVenus, from Venera 13 (Natural Colors; credits: Ted Stryk)66 visiteTed Stryk comments:"...Here is the other Venera 13 pan. The color data is OK on the sides, but in the center, all color data is nearly blank, making any color variations dubious in that part of the image...".
MareKromiumMar 08, 2009
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Venusian_Surface-Venera_13-09a.jpgVenus, from Venera 13 (Natural Colors; credits: Ted Stryk)53 visiteTed Stryk comments:"...Here is a composite of Venera 13 images, looking towards a ridge on the horizon...I have watched with great excitement how the Mars Exploration Rovers have explored the Red Planet.
However, Venus, while it has had more successful landers on its Surface, was the subject of much less capable Spacecraft. There are four color image sets of the Surface, all with blank or nearly blank blue channels. Venera 13 sent back one full pan in color, which is the best set we have, and another partial one (complete in black and white) that hs much poorer color data..."
Nota Lunexit: non lo diciamo (rectius: scriviamo) certo per polemizzare con Mr Ted Stryk, nè per "esaltare" le imprese dell'Agenzia Spaziale Sovietica, ma il paragone fra le capacità dei Lander della Classe "VENERA" che raggiunsero con successo la Superficie di Venere ed i MER Spirit ed Opportunity (nonchè i Lander Viking 1, 2, Pathfinder e Phoenix) che hanno felicemente raggiunto la Superficie del Pianeta Rosso e che Ted stesso opera per giungere alla conclusione che i Venera Lander erano "...much less capable spacecraft..." non sta nè in Cielo, nè...su Marte o Venere!
Tralasciamo in questa sede il gap di evoluzione tecnica che separa le Sonde VENERA (fine Anni '70, primi Anni '80) da quelle NASA e focalizziamoci sulle condizioni della Superficie di Venere rispetto a quelle della Superficie Marziana: avete un'idea - anche vaga - della diversità di ambienti?
Temperatura media al suolo su Venere: tra i 465 ed i 485° Celsius; pressione: 92/94 Bar (e cioè oltre 9 volte la pressione terrestre al livello del mare); il tutto condito da vulcanismo attivo e frequenti piogge a base di Acido Solforico.
Come si fa, viste le summenzionate premesse, a dire che le Sonde Sovietiche erano "più scadenti"??? Insomma: di paragoni se ne possono sempre fare, certo, ma devono essere "sensati" e fondati su oggetti e situazioni congruibili, altrimenti...sono solo chiacchiere in libertà.MareKromiumMar 08, 2009
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Venusian_Surface-Venera_14-03.jpgVenus, from Venera 14 (Natural Colors; credits: Ted Stryk)54 visiteTed Stryk comments:"...Venera 14, which landed in a much rockier area, took a pretty good partial color pan (again, complete in black and white), but while the other pan was complete in both black and white and through color filters (althoug again the blue was almost useless), the color data in this set was horribly underexposed.
Here is the Venera 14 partial pan, my favorite of the set because of the cool rock right near the lander. It seems to be sitting on the rocky plain...it makes one wonder how it got there. I don't see anything else like it in the Venera pans, although given their limited coverage, it doesnt mean there aren't perhaps a few more rocks like it around. But still , it is lucky it was so close to the lander and in a color zone...".
Nota Lunexit: notate anche Voi una - secondo noi STRAORDINARIA - similitudine fra questa superficie e la superficie di Titano?...MareKromiumMar 08, 2009
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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 commentoMareKromiumFeb 26, 2008
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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".MareKromiumFeb 26, 2008
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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".MareKromiumFeb 26, 2008
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Venusian_Clouds_and_Haze-27_VMC_polar_views_H.jpgVenusian "Variable Clouds" and "Hazes"53 visiteCaption ESA:"This is a composite of several ultraviolet (365-nnmts) images taken with the Venus Monitoring Camera (VMC) on board ESA’s Venus Express.
These images show variability of the clouds and hazes in Venus’ South Polar Region.
The South Pole is at the Terminator in the bottom-left of the images.
Super-Rotation, a phenomenon where cloud layers on Venus rotate much faster than the surface below, is in the anticlockwise direction. The period of Super-Rotation varies between 3 and 5 days, depending on the latitude.
The images a, b and c in the top row were taken between 27 and 30 June 2006, at a distance of about 65.000 Km from the Planet.
It is obvious from the pictures that the near-polar features vary from one day to another.
An extreme case of such variability is shown in Figure d (obtained on 13 January 2007, from about 35.000 Km). The bright haze located above the absorbing cloud layer has expanded to 35º South and has also become denser, masking all features except the oval. This dense haze disappeared within a day, probably due to very quick coagulation of aerosols making up the haze.
The figure in panel e (obtained on 27 December 2006, from about 38.000 Km) shows the full view of the Southern Hemisphere from the Equator (right) to the Pole".MareKromiumFeb 26, 2008
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Venusian_Clouds-29_VM_Pericentre_mosaic_H.jpgChaotic "Cloud Patterns" at Venus53 visiteCaption ESA:"This mosaic of Venus’ cloud tops was put together with several images obtained by the Venus Monitoring Camera (VMC) on board ESA’s Venus Express. The images where taken in the ultraviolet (365-nanometre wavelength) on 15 August 2006 at distances from 5000 to 1000 Km from the Planet.
The picture clearly shows streaks, wave trains and convection cells. The elongated orbit of Venus Express allows one to zoom into the cloud features as the Spacecraft approaches the Planet. This mosaic shows that mottled and chaotic cloud patterns at low latitudes give way to oriented streaks at about 15° South.
This behaviour indicates transition between two different cloud motion regimes – a ‘dynamic’ regime dominated by local convection where the Sun light hits the Planet perpendicularly (so-called "Sub-Solar Point") - and a more regular, quasi-laminar-flow regime".
MareKromiumFeb 26, 2008
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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".MareKromiumFeb 26, 2008
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Venusian_Atmosphere_and_the_Solar_Wind-Interaction.jpgInteraction between Venus and the Solar Wind55 visiteCaption ESA:"Mars, Earth and Venus are immersed in a flow of plasma, a ionised and highly variable gas originating from the Sun, called the Solar Wind. While Earth has a Planetary Magnetic Field, which can deviate its flow, Venus (and Mars) don’t.
Gases in the upper atmospheres of these Planets are ionised, and can thus interact with the Solar Wind. Venus is as large as Earth and it is difficult for its Atmosphere to escape due to the Planet’s Gravity. The Solar Wind is the best source of energy to accelerate the upper atmosphere’s charged particles, giving them enough energy to escape. This is why Venus loses its atmosphere due to interaction with the Solar Wind.
To understand this phenomenon, the key questions that the instruments studying plasma on Venus Express must answer are: what and how much of the Atmosphere is lost, and where is it lost? Right now, solar activity is at its minimum in the 11-year cycle, making the Solar Wind weaker than average.
The critical question now is how solar wind interacts with Venus when solar activity is low".MareKromiumFeb 26, 2008
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