Copyright:
Allisha Libby
原文:
What’s happening behind those houses? Pictured here are not auroras but nearby light pillars, a nearby 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. The featured image was taken in Fort Wainwright near Fairbanks in central Alaska. Follow APOD on: Facebook, Google Plus, or Twitter
中文翻譯:
🌌 有什麼隱藏在這些房子後面？這裡看到的不是極光，而是附近的光柱，一種似乎遠處出現的現象。在地球上的大多數地方，幸運的觀眾可以看到日柱，這是一條看似從太陽延伸出的光柱，是由平坦的冰晶在大氣上層反射陽光所造成的。這些冰晶通常會在到達地面之前蒸發。然而，在寒冷的氣候中，平坦的冰晶可能會在接近地面的地方形成一種輕微的雪，通常稱為晶霧。這些冰晶會反射地面燈光，形成類似於日柱的光柱。這幅圖片是在阿拉斯加中部的法爾班克斯（Fairbanks）附近的韋恩賴特堡（Fort Wainwright）拍攝的。
#光柱 #日柱 #極光 #阿拉斯加 #自然奇觀 #光影藝術
來源:NASA每日圖片
