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South Polar Halo.jpgSouth Polar Halo61 visiteWhen Sunlight reflects and refracts off of tiny ice crystals in the atmosphere, the result can be ice crystal halos, which are related to rainbows (the latter being produced when Sunlight reflects and refracts from water droplets).
In Antarctica the temperatures are cold and the air is dry, so snow crystals grow very slowly. This slow growth tends to produce very clean hexagonal prisms, which are well suited for producing beautiful atmospheric displays. The example here is a South Pole halo, showing a rich variety of arcs and halos.
Halos arise from the way minute ice crystals in the atmosphere scatter Sunlight (or Moonlight!) into different angles.
The quality of a halo depends on the type and quality of the ice crystals that produce it.
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Sun Pillars.jpgLight Pillars' Parade77 visiteDa "NASA - Picture of the Day" del 5 Marzo 2006:"How can an aurora appear so near the ground? Pictured above are not aurora but nearby light pillars, a local phenomenon that can appear as a distant one. In most places on Earth, a lucky viewer can see a Sun-pillar, a column of light appearing to extend up from the Sun caused by flat fluttering ice-crystals reflecting sunlight from the upper atmosphere. Usually these ice ice crystals evaporate before reaching the ground. During freezing temperatures, however, flat fluttering ice crystals may form near the ground in a form of light snow, sometimes known as a crystal fog. These ice crystals may then reflect ground lights in columns not unlike a Sun-pillar. In the above picture, the colorful lights causing the light pillars surround a ice-skating ring in Fairbanks, Alaska".
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