Noctilucent Clouds Over Sweden

影像提供: P-M Hed
Explanation:
     Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above. Under usual circumstances, a pretty sunset might be visible, but unusual noctilucent clouds float so high up they can be seen well after dark. Pictured above last month, a network of noctilucent clouds cast a colorful but eerie glow after dusk near Vallentuna, Sweden. Although noctilucent clouds are thought to be composed of small ice-coated particles, much remains unknown about them. Recent evidence indicates that at least some noctilucent clouds result from freezing water exhaust from Space Shuttles.
說明:
      有時候，地面已是黑夜但高空仍是白晝。隨著地球自轉擋住太陽，黃昏降臨大地，此時，地面已是黃昏，但陽光仍然照耀著上空的雲彩；在一般的情況下，所見到的是美麗的晚霞，不過如果高空有雲，在天黑很久之後，可以見到罕見的夜光雲 (noctilucent clouds)。上面這張在上個月拍攝的影像裡，網絡狀的夜光雲，讓瑞典．Vallentuna的夜空變得既多彩且怪誕。雖然一般認為夜光雲是由細小的冰晶所構成的，不過它們的特性大多仍是未知。最近的證據顯示至少有些夜光雲，是由太空梭所排放的水結晶而成。
資料來源: Scientific American
                 Department of Physics, NCKU

沙发  好美哦 好看啊

不錯耶  .  好美 . 謝謝分享

太空梭排放的冰晶那麼一大片要多少太空梭啊

很美阿只是沒看見外星人

哇  太長見識了

太美了，不过我想不会是太空梭造成的吧》？

真想看一看{:3_317:}