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原文:
On the Moon, the Earth never rises — or sets. If you were to sit on the surface of the Moon, you would see the Earth just hang in the sky. This is because the Moon always keeps the same side toward the Earth. Curiously, the featured image does picture the Earth setting over a lunar edge. This was possible because the image was taken from a spacecraft orbiting the Moon – specifically the Lunar Reconnaissance Orbiter (LRO). In fact, LRO orbits the Moon so fast that, from the spacecraft, the Earth appears to set anew about every two hours. The featured image captured one such Earthset about three months ago. By contrast, from the surface of the Earth, the Moon sets about once a day — with the primary cause being the rotation of the Earth. LRO was launched in 2009 and, while creating a detailed three dimensional map of the Moon’s surface, is also surveying the Moon for water and possible good landing spots for future astronauts. Free APOD Lectures: Editor to speak this coming weekend in Philadelphia and New York City
中文翻譯:
在月球上，地球不會升起或落下。如果你坐在月球表面，你會看到地球靜靜地懸掛在天空中。這是因為月球總是將同一面朝向地球。有趣的是，標題中的圖片顯示了地球在月球邊緣的落下。這種情況是因為圖片是由一艘繞月軌道飛行的太空船拍攝的——具體而言，是月球勘探衛星 (Lunar Reconnaissance Orbiter, LRO)。事實上，LRO 繞月的速度之快使得地球大約每兩個小時就會出現一次新的”地球落下”。這張圖片捕捉了大約三個月前的其中一次地球落下。相比之下，從地球的表面來看，月球大約每天會落下一次——這主要是由於地球的自轉。LRO 於2009年發射，除了建立月球表面的詳細三維地圖外，還在調查月球上的水源和未來宇航員的合適著陸點。
#月球 #地球 #LunarReconnaissanceOrbiter #LRO #探索宇宙 #太空 #太空探索 #天文學 #地球落下 #月球旅遊 #宇航員未來
來源:NASA每日圖片
