APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Colorful Light Pillars
Explanation: 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 .
| Date | September 2, 2002 |
|---|---|
| Credit | Credit & Copyright: Walter Tape ( Alaska Fairbanks ), Figure 8-1, Atmospheric Halos |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |



