| Piú viste - Venus |
Venusian_Surface-Venera_13-09a.jpgVenus, from Venera 13 (Natural Colors; credits: Ted Stryk)54 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.MareKromium
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Craters-Fossey_Crater-PCF-LXTT-01.jpgFossey Crater (Natural Colors; credits: Lunar Explorer Italia)54 visitenessun commentoMareKromium
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Craters-Balch_Crater-1.jpgBalch Crater (Natural Colors; credits: Lunar Explorer Italia)54 visitenessun commentoMareKromium
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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".MareKromium
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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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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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