银河极光
(原标题: Milky Way Auroral Flower)
2022-10-18
浏览次数: 15
我们银河系的茎能开出一朵极光花吗？不，不是真的，即使在今天的全天空图像中看起来是这样。在左边，我们银河系的中心平面从地平线延伸到天空中央。在右边，一个极光椭圆也从天空的中心延伸出来，但主要是明亮的绿色发光的氧气。两者在物理上没有联系，因为极光相对较近，较高的红色部分出现在地球大气层中，高度仅为1000公里左右。相比之下，我们在银河系中看到的恒星和星云的平均距离更像是1000光年远——10万亿倍远。这张特色合成图像是10月初在瑞典北部阿比斯库的一个小湖上拍摄的。随着太阳磁场进入其11年周期的活跃期，地球两极附近的极光肯定会变得更加频繁。
查看原文解释
Could the stem of our Milky Way bloom into an auroral flower? No, not really, even though it may appear that way in today’s featured all-sky image. On the left, the central plane of our home galaxy extends from the horizon past the middle of the sky. On the right, an auroral oval also extends from the sky's center -- but is dominated by bright green-glowing oxygen. The two are not physically connected, because the aurora is relatively nearby, with the higher red parts occurring in Earth's atmosphere only about 1000 kilometers high. In contrast, an average distance to the stars and nebulas we see in the Milky Way more like 1000 light-years away - 10 trillion times further. The featured image composite was taken in early October across a small lake in Abisko, northern Sweden. As our Sun's magnetic field evolves into the active part of its 11-year cycle, auroras near both of Earth's poles are sure to become more frequent.
© Göran Strand