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Moon_and_Mars.jpgIn the Twilights...114 visitenessun commentoMareKromium
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VENUS_MERCURY.jpgMercury and Venus from Earth113 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 (ci 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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Moon Ecyipse - Stonehenge.jpgEclipse over an ancient observatory...113 visiteImmagine amatoriale molto bella e decisamente suggestiva...
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Solar_Green-Flash.jpgA "Green Flash" from the Sun112 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 Space111 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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In the Mind-1.jpgIn the mind111 visitenessun commento
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Gliese-581-1.jpgSunrise from Gliese 581c111 visitenessun commentoMareKromium
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Hyblaeus_Mons~0.jpgHyblaeus Mons (by Dr Gianluigi Barca)111 visitenessun commentoMareKromium
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ZZ-Jupiter and Venus.jpgJupiter and Venus in the dawn110 visiteUna spettacolare congiunzione Giove-Venere del Novembre 2004, come ripresa, pochi minuti prima dell'alba, nei cieli della Turchia (la citt che appare nello sfondo Bursa).
Si tratta di una fotografia amatoriale - a posa breve - ottenuta con estrema semplicit e senza l'ausilio - a quanto ci dato vedere - di particolari accortezze tecniche.
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Meteor.jpgMeteor over Italy110 visitenessun commentoMareKromium
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Hyblaeus_Mons.jpgHyblaeus Mons (by Roberto Tremolada)109 visitenessun commentoMareKromium
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Sun_Pillar.jpgA light "Sun-pillar" from somewhere in USA108 visiteCaption originale NASA. "Have you ever seen a sun pillar? When the air is cold and the Sun is rising or setting, falling ice crystals can reflect sunlight and create an unusual "column of light". Ice sometimes forms flat, stop-sign shaped crystals as it falls from high-level clouds; air resistance causes these crystals to lie nearly flat much of the time as they flutter to the ground. Then sunlight reflects off crystals that are properly aligned, creating the so-called "Sun-pillar" effect".
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