Colorful Light Pillars

Astronomy Picture of the Day · 2002-09-02 · NASA (public domain)

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Colorful Light Pillars — APOD for 2002-09-02

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 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 rink in Fairbanks, Alaska .

Astronomy Picture of the Day for 2002-09-02 — image & explanation courtesy of NASA (public domain), mirrored at Tukuk-OS for reading and search convenience.

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