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.
2002 December 30 
Posted on 12/30/2002 12:21:46 AM PST by petuniasevan
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.
2002 December 30
Explanation: 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. Sunlight reflects off crystals that are properly aligned, creating the sun-pillar effect. In the above picture, a sun-pillar reflects light from a setting Sun.
More APOD halos for your enjoyment:
There is a white spot with no color in the sky at the opposite position of the sun at the same altitude and a showshoe shaped figure tangent to the ring at the top above the sun that crosses over the top of the sky and ends up at the white spot.
The white ring horizontal to the ground goes all the way around the sky and meets the white spot opposite the sun.
Note the prismatic colors at the bright spots and note also that the interior of the ring is darker than the rest of the sky. The light for the display comes from the inside of the ring.
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