新月海王星和海卫一
(原标题: Crescent Neptune and Triton)
2021-07-25
浏览次数: 37
旅行者2号飞船的照相机悄无声息地掠过外太阳系，捕捉到了海王星和海卫一一起处于月牙相的景象。这张优雅的冰巨行星和它的多云卫星的照片是1989年在最接近地球时从背后拍摄的。它不可能是从地球上拍摄的，因为海王星从来没有对着太阳的地球呈现新月形。这个不寻常的有利位置也剥夺了海王星熟悉的蓝色色调，因为从这里看到的阳光是向前散射的，所以像夕阳一样变红了。海王星比天王星更小，但质量更大，有几个暗环，发射的光比从太阳接收的光还要多。
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Gliding silently through the outer Solar System, the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase. The elegant picture of the ice-giant planet and its cloudy moon was taken from behind just after closest approach in 1989. It could not have been taken from Earth because Neptune never shows a crescent phase to sunward Earth. The unusual vantage point also robs Neptune of its familiar blue hue, as sunlight seen from here is scattered forward, and so is reddened like the setting Sun. Neptune is smaller but more massive than Uranus, has several dark rings, and emits more light than it receives from the Sun.