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The Moon.jpgThe Moon "in flames"111 visitenessun commento
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Time_to_Change.jpgTime to Change (by Dr Gianluigi Barca)111 visitenessun commentoMareKromium
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Up_and_Above.jpgUp and Above (by Dr Gianluigi Barca)111 visitenessun commentoMareKromium
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Fireball.jpgTime to sleep...110 visitenessun commento
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Moon_and_Mars.jpgIn the Twilights...110 visitenessun commentoMareKromium
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Glory.jpgGlory never fades...109 visiteIf you tried to enter this hall of fog, you would find it dissipates around you. The hall is actually an the mountain from which this picture was taken.
Known as "The Glory", the phenomenon is frequently seen from airplanes. The ring's center is not visible, but if it were, the shadow of the observer would appear. This shadow would likely change as clouds passed, creating a faux moving giant known as the Brocken Spectre.
Pictured above, several concentric rings of the glory appear to create a hall for this mountain king. The cause of The Glory has only been understood recently and is relatively complex. Briefly, small droplets of water reflect, refract, and diffract Sunlight backwards towards the Sun. The phenomenon has a counterpart in astronomy, where looking out from planet Earth in the direction opposite the Sun yields a bright spot called "The Gegenschein".MareKromium
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DAWN.jpgThe Dawn of Man108 visiteUn fotogramma storico, dall'indimenticabile "2001 - A Space Odyssey": l'Alba dell'Uomo.
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Iridescent_Cloud.jpgIridescent Cloud108 visiteCaption NASA:"Why would a cloud appear to be different colors? A relatively rare phenomenon known as "Iridescent Clouds" can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size. When the Sun is in the right position and mostly hidden by thick clouds, these thinner clouds significantly diffract sunlight in a nearly coherent manner, with different colors being deflected by different amounts. Therefore, different colors will come to the observer from slightly different directions. Many clouds start with uniform regions that could show iridescence but quickly become too thick, too mixed, or too far from the Sun to exhibit striking colors.
This iridescent cloud was photographed above Boulder, Colorado last week".MareKromium
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Solar_Green-Flash.jpgA "Green Flash" from the Sun108 visiteDalla Rubrica "NASA - Picture of the Day" del giorno 4 Gennaio 2011:"Many people think it is just a myth. Others think it is true but its cause isn't yet known. Adventurers pride themselves on having seen it.
What is it?
It's a "Green Flash" from the Sun. The truth is the Green Flash does exist and its cause is well understood.
Just as the setting Sun disappears completely from view, a last glimmer appears startlingly green.
The effect is typically visible only from locations with a low, distant horizon, and lasts just a few seconds. A Green Flash is also visible for a rising Sun, but takes better timing to spot.
A dramatic Green Flash, as well as an even more rare Blue Flash, was caught in the above photograph recently observed during a Sunset visible from Teide Observatory at Tenerife, Cannary Islands, Spain.
Obviously, the Sun does not partly turn either green or blue: the effect is caused by different layers of the Earth's Atmosphere, together acting like a prism".MareKromium
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ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-PIA07997-2-plusRover-A667R1.jpgVirtual Presence in Space107 visiteThis synthetic image of the Spirit MER on top of a rock called "Jibsheet" was produced using "Virtual Presence in Space" technology. Developed at NASA's Jet Propulsion Laboratory, Pasadena, Calif., this technology combines visualization and image-processing tools with Hollywood-style special effects. The image was created using a photorealistic model of the Rover and a false-color mosaic. The size of the Rover in the image is approximately correct and was based on the size of the Rover tracks in the mosaic. The mosaic was assembled from frames taken by the Pan-Cam on the Rover's 489th Martian day (May 19, 2005); see PIA07997.
Because this synthesis provides viewers with a sense of their own "virtual presence" (as if they were there themselves), such views can be useful to mission teams in planning exploration by enhancing perspective and a sense of scale.
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Moon Ecyipse - Stonehenge.jpgEclipse over an ancient observatory...107 visiteImmagine amatoriale molto bella e decisamente suggestiva...
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VENUS_MERCURY.jpgMercury and Venus from Earth106 visiteGli elementi sino ad ora individuati in questa "esosfera" sono H, He, O2, Na, K e Ca.
I primi 2 elementi giungono, molto probabilmente, dalla corrente di gas ionizzati proveniente dal Sole (ciņ che comunemente chiamiamo "Vento Solare"), mentre gli altri 4 potrebbero scaturire direttamente dalle rocce esistenti sulla (o al di sotto della) superficie di Mercurio.
Come? Abbiamo tre ipotesi al riguardo (e tutte ugualmente plausibili):
1) potrebbe trattarsi di una lenta "evaporazione" (!) delle rocce superficiali causata dalla (e, per lunghi periodi di tempo, costante) temperatura elevatissima;
2) fenomeni di "outgassing" simili a quelli che - si dice - accadano anche sulla nostra Luna (si tratta di sacche di gas, imprigionate da ere ed ere al di sotto della superficie del Pianeta, che si liberano improvvisamente - a seguito di eventi sismici o di impatti veri e propri - e fuoriescono, ora incendiandosi e generando delle "flares" - fiammate o fiaccole -, ora disperdendosi nell'ambiente circostante);
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