Copyright:Clear Skies
中文翻譯:
在一個燦爛的夏天，陽光在天色逐漸變暗時依然閃爍著，讓我們看到了特別的雲朵，叫做夜光雲（noctilucent clouds）。這一美妙的場景是在瑞典斯德哥爾摩附近的瓦倫圖納湖拍攝的。這些雲朵形成在距離地面約80公里的高空，當太陽已經在地平線以下時，它們依然會反射陽光。這些雲朵通常在夏天的北半球高緯度地區出現，這正是它們展現美麗的時候哦！它們的形成是因為水蒸氣被推進寒冷的高空，然後在隨著流星或火山灰分解的微小塵埃顆粒上凝結而成的。
原文:
Transfusing sunlight as the sky grew darker, this exceptional display of noctilucent clouds was captured on July 10, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space, about 80 kilometers above Earth’s surface, the icy clouds themselves still reflect sunlight, even though the Sun is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months, the night shining clouds have made a strong showing so far during the short northern summer nights. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors or volcanic ash.
來源:NASA每日圖片
