Copyright:
原文:
That is not our Moon. It’s Dione, and it�s a moon of Saturn. The robotic Cassini spacecraft took the featured image during a flyby of Saturn’s cratered Moon last month. Perhaps what makes this image so interesting, though, is the background. First, the large orb looming behind Dione is Saturn itself, faintly lit by sunlight first reflected from the rings. Next, the thin lines running diagonally across the image are the rings of Saturn themselves. The millions of icy rocks that compose Saturn’s spectacular rings all orbit Saturn in the same plane, and so appear surprisingly thin when seen nearly edge-on. Front and center, Dione appears in crescent phase, partially lit by the Sun that is off to the lower left. A careful inspection of the ring plane should also locate the moon Enceladus on the upper right.
中文翻譯:
這不是我們的月球。它是Dione，土星的一個衛星。機械人太空船Cassini在上個月的一次掠過中拍攝了這幅引人注目的圖像。 這張圖片之所以如此有趣，部分原因在於背景。首先，伫立在Dione背後的巨大圓球是土星，淡淡地被陽光照亮，這陽光是從環帶反射過來的。然後，圖像中斜向運行的細線是土星的環。
組成土星壯觀環帶的數百萬塊冰冷的岩石，均在同一平面上繞著土星運行，因此當幾乎以邊緣的視角觀察時，它們看起來意外地薄。在圖像的中央，Dione呈現出弦月形狀，部分受到位於左下方的太陽照亮。仔細檢查環帶平面，還可以在右上方找到衛星Enceladus的身影。
#Dione #Saturn #Cassini #SpaceExploration #Astrophotography #Enceladus #PlanetaryScience #CrescentMoon #SaturnRings #CelestialWonders
來源:NASA每日圖片
