西西里島上空的反暮光射線

Anticrepuscular Rays over Sicily

來源：Marcella Giulia Pace
Text:
Cecilia Chirenti
(NASA
GSFC,
UMCP,
CRESST II)｜發表日期：2026-06-25

太陽剛剛落山……不過是在天空的另一側。這張拍攝於義大利西西里島東南部海布萊山脈腹地的一處石灰岩高原的照片中，可見反暮光射線似乎正向東方匯聚。既然太陽不在那裡，這些反暮光射線是如何形成的呢？太陽落山後（像往常一樣在西方落下），它的光線仍然照亮了高空中的雲層。陽光被雲層部分遮擋，形成了光影交織的圖案，以平行線的形式橫跨天空。由於透視效應，這些光線看起來彷彿在東方匯聚，就像遠處的鐵軌似乎在遠處交匯一樣。這種現象在日出時也會發生，只是方向相反。在極少數情況下，可以同時看到暮光射線和反暮光射線。

原文：The Sun has just set... in the opposite side of the sky. Pictured here are anticrepuscular rays apparently converging in the east in this image of the limestone plateau in the heart of the Hyblaean Mountains of southeastern Sicily, in Italy. How were these anticrepuscular rays formed, if the Sun wasn't there? After the Sun set (in the west, as usual) its light still illuminated a cloud higher up in the sky. Partially blocked by the cloud, the sunlight produced patterns of light and shadow, crossing the sky in parallel lines. Perspective makes it look like they converge in the east, in the same way that train tracks appear to meet in the distance. This effect can also happen at sunrise, only the directions are exchanged. In rare cases, both crepuscular and anticrepuscular rays can be seen at the same time.

※ 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！

關於每日一天文圖：每日一天文圖網站是美國國家航空暨太空總署與密西根理工大學提供的服務，網站每天提供一張影像或圖片，並由天文學家撰寫扼要說明其特別之處。