美国国家航空航天局NASA每日一图(天文)-2017年7月17日

2017 July 17

Moon Shadow versus Sun Reflection
Image Credit: Himawari-8, NASA's SVS (GSFC)
Explanation: What are those lights and shadows crossing the Earth? As the featured five-second time-lapse video progresses, a full day on planet Earth is depicted as seen from Japan's Himawari-8 satellite in geostationary orbit high above the Pacific Ocean. The Sun rises to the right and sets to the left, illuminating the half of Earth that is most directly below. A reflected image of the Sun -- a Sun glint -- is visible as a bright spot that moves from right to left. More unusual, though, is the dark spot that moves from the lower left to upper right That is the shadow of the Moon, and it can only appear when the Moon goes directly between the Earth and the Sun. Last year, on the day these images were taken, the most deeply shadowed region experienced a total eclipse of the Sun. Next month a similarly dark shadow will sweep right across the USA.

2017年7月17日

月影与太阳反射
图片来源:Himawari-8,NASA的SVS(GSFC)
说明:这些灯光和阴影穿过地球是什么? 随着特色五秒钟延时视频的进行,地球上一整天的时间从日本的Himawari-8卫星在太平洋上方的地球静止轨道上可以看出。 太阳向右上升,向左倾斜,照亮了最下方的地球一半。 太阳的反射图像 - 一个太阳闪光 - 是可见的,从右向左移动的亮点。 更不寻常的是,从左下角到右上方的黑点是月球的阴影,只有当月球直接在地球和太阳之间时,才会出现。 去年,在拍摄这些图像的那一天,最阴影的地区经历了太阳的全日食。 下个月,类似的阴影将在美国横扫。

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