地球之臍
The Umbra of Earth
來源：Wang Letian｜發表日期：2025-09-11
地球內部的暗影被稱為本影。它的形狀像一個向太空延伸的圓錐體，在月食期間最容易看到它的圓形截面。 9 月 7 / 8 日晚，滿月在地球本影圓錐中心附近劃過，我們美麗星球的大部分地區，包括南極洲、澳大利亞、亞洲、歐洲和非洲部分地區的月食觀測者都為之驚歎。這幅延時攝影合成圖從中國張家口市拍攝，採用月全食的連續照片，從左到右，展現了本影滑過月球的曲線截面。全食期間，大氣層散射到地球本影的太陽光使月球表面呈現紅色。但在接近本影邊緣時，被食月球的邊緣會呈現出明顯的藍色。藍色的食月光源自太陽光穿過高高的平流層，臭氧層散射紅光並透射藍光。在這次悠閒月食的全食階段，月球完全位於地球本影內約 83 分鐘。
原文：The dark, inner shadow of planet Earth is called the umbra. Shaped like a cone extending into space, it has a circular cross section most easily seen during a lunar eclipse. And on the night of September 7/8 the Full Moon passed near the center of Earth's umbral cone, entertaining eclipse watchers around much of our fair planet, including parts of Antarctica, Australia, Asia, Europe, and Africa. Recorded from Zhangjiakou City, China, this timelapse composite image uses successive pictures from the total lunar eclipse, progressing left to right, to reveal the curved cross-section of the umbral shadow sliding across the Moon. Sunlight scattered by the atmosphere into Earth's umbra causes the lunar surface to appear reddened during totality. But close to the umbra's edge, the limb of the eclipsed Moon shows a distinct blue hue. The blue eclipsed moonlight originates as rays of sunlight pass through layers high in the upper stratosphere, colored by ozone that scatters red light and transmits blue. In the total phase of this leisurely lunar eclipse, the Moon was completely within the Earth's umbra for about 83 minutes.
※ 本文由萌芽機器人自動轉貼自每日一天文圖（Astronomy Picture of the Day，APOD），原文為英文，正體中文是透過 DeepL 翻譯及 OpenCC 進行自動處理，內容僅供參考，若有任何錯誤之處還請見諒！
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