NASA·APOD每日天文一图2022.5.15 [超高清]

What color is the Moon? It depends on the night. Outside of the Earth's atmosphere, the dark Moon, which shines by reflected sunlight, appears a magnificently brown-tinged gray. Viewed from inside the Earth's atmosphere, though, the moon can appear quite different. The featured image highlights a collection of apparent colors of the full moon documented by one astrophotographer over 10 years from different locations across Italy. A red or yellow colored moon usually indicates a moon seen near the horizon. There, some of the blue light has been scattered away by a long path through the Earth's atmosphere, sometimes laden with fine dust. A blue-colored moon is more rare and can indicate a moon seen through an atmosphere carrying larger dust particles. What created the purple moon is unclear -- it may be a combination of several effects. The last image captures the total lunar eclipse of 2018 July -- where the moon, in Earth's shadow, appeared a faint red -- due to light refracted through air around the Earth. Today there is not only another full moon but a total lunar eclipse visible to observers in North and South America -- an occurrence that may lead to some unexpected lunar colorings. 

月亮是什么颜色的？这取决于夜晚。在地球大气层之外，被反射的阳光照射的暗月亮呈现出一种富丽堂皇的棕灰色。然而，从地球大气层内部看，月球可能看起来完全不同。这张特色图片突出显示了一位天文摄影师10年来从意大利各地记录的满月的一系列明显颜色。红色或黄色的月亮通常表示在地平线附近看到的月亮。在那里，一些蓝光在地球大气层中被一条很长的路径散射掉，有时还夹杂着细尘。蓝色的月亮更为罕见，它可以表示在大气层中看到的带有较大尘埃颗粒的月亮。紫月亮的形成原因尚不清楚——它可能是多种效应的组合。最后一张照片拍摄的是2018年7月的月全食——由于光线通过地球周围的空气折射，月球在地球的阴影中呈现出微弱的红色。今天，北美和南美的观测者不仅可以看到另一轮满月，还可以看到一次月全食——这种情况可能会导致一些意想不到的月球颜色。