极光覆盖天空
(原标题: Aurora Slathers Up the Sky)
2026-05-16
浏览次数: 73
就像你最喜欢的墨西哥卷饼上的绿辣酱一样，在2017年6月25日国际空间站拍摄的这张照片中，绿色的极光笼罩着天空。距地球约400公里（250英里）的轨道空间站本身就在极光显示的上层区域。极光具有激发态分子和原子的标志性颜色，这些分子和原子处于极端海拔的低密度。原子氧的发射主导了这一观点。在较低的海拔高度，诱人的光芒是绿色的，但在空间站的地平线上延伸出罕见的红色带。这张照片是在经过澳大利亚东部和南部的一个点时拍摄的，右边地平线上的星星属于大犬座，猎户座的大狗。天狼星是大犬座的阿尔法星，是地球边缘附近最亮的恒星。
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Like salsa verde on your favorite burrito, a green aurora slathers up the sky in this 2017 June 25 snapshot from the International Space Station. About 400 kilometers (250 miles) above Earth, the orbiting station is itself within the upper realm of the auroral displays. Aurorae have the signature colors of excited molecules and atoms at the low densities found at extreme altitudes. Emission from atomic oxygen dominates this view. The tantalizing glow is green at lower altitudes, but rarer reddish bands extend above the space station's horizon. The orbital scene was captured while passing over a point south and east of Australia, with stars above the horizon at the right belonging to the constellation Canis Major, Orion's big dog. Sirius, alpha star of Canis Major, is the brightest star near the Earth's limb.