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.
2006 January 2
http://antwrp.gsfc.nasa.gov/apod ... ine_orloski_big.jpg
A Sun Pillar Over Maine
Credit & Copyright: Lucy Orloski
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 taken late last month, a sun-pillar reflects light from a Sun setting over Bangor, Maine, USA.
说明：你曾经看到过一束光柱吗？当日落或是日出时，如果空气寒冷，下落的冰晶就会反射阳光形成一道不寻常的光柱。当冰从高层的云中下落时，有时就会形成扁平的、有棱角的（禁止符号形状）冰晶。在这些冰晶飘落到地面的过程中，空气的阻力使得它们大部分时间保持近似扁平状。当冰晶完全排列成线形时，反射阳光就会形成光柱效应。上图拍摄于上月末日落时分，在美国 缅因州班戈市上空有一束反射阳光形成的光柱。（翻译：刘媛媛）
Tomorrow's picture: new rings and moons
[ Last edited by 夜空 on 2006-1-4 at 03:31 PM ]
[ 本帖最后由 夜空 于 2006-2-23 03:58 PM 编辑 ] | 
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