火星上的暗沙瀑布
Dark Sand Cascades on Mars
發表日期：2025-06-29
這些樹是長在火星上的嗎？不是。火星勘測軌道飛行器在融化的粉紅色沙丘上拍攝到了成群的深褐色條紋，沙丘上覆蓋著薄薄的冰霜。這張照片是 2008 年 4 月在火星北極附近拍攝的。當時，隨著春季太陽融化較淺的二氧化碳冰，火星沙丘內部的深色沙子變得越來越清晰可見。 當出現在沙丘頂部附近時，深色沙子可能會順著沙丘流下，在沙丘表面留下深色條紋--這些條紋初看起來可能是站在淺色區域前面的樹木，但沒有投下陰影。在這幅橫跨約一公里的影像上，可以分辨出直徑約 25 釐米的物體。該影像某些部分的特寫顯示出波浪狀的羽流，表明在拍攝影像時就已經出現了滑沙現象。 天體驚喜：你的生日那天，APOD 刊登了哪張照片？ （ 1995 年後）
原文：Are these trees growing on Mars? No. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The featured image was taken in 2008 April near the North Pole of Mars. At that time, dark sand on the interior of Martian sand dunes became more and more visible as the spring Sun melted the lighter carbon dioxide ice. When occurring near the top of a dune, dark sand may cascade down the dune leaving dark surface streaks -- streaks that might appear at first to be trees standing in front of the lighter regions but cast no shadows. Objects about 25 centimeters across are resolved on this image spanning about one kilometer. Close ups of some parts of this image show billowing plumes indicating that the sand slides were occurring even while the image was being taken. Celestial Surprise: What picture did APOD feature on your birthday? (post 1995)
※ 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。