2025年1月7日
A New Year’s Aurora and SAR Arc
Image Credit & Copyright: Alessandra Masi
Explanation: It was a new year, and the sky was doubly red. The new year meant that the Earth had returned to its usual place in its orbit on January 1, a place a few days before its closest approach to the Sun. The first of the two red skyglows, on the left, was a red aurora, complete with vertical rays, caused by a blast from the Sun pushing charged particles into Earth’s atmosphere. The second red glow, most prominent on the far right, was possibly a SAR arc caused by a river of charged particles flowing across Earth’s atmosphere. Although both appear red, the slight color difference is likely due to the aurora being emitted by both oxygen and nitrogen, whereas the higher SAR arc was possibly emitted more purely by atmospheric oxygen. The featured image was taken on January 1 from near Pieve di Cadore in Italy.
Portal Universe: Random APOD Generator
Tomorrow’s picture: supernovas (plural)
新年元旦的极光与稳定极光红弧
影像提供与版权: Alessandra Masi
说明: 元旦那天，天空出现二种红色辉光。元旦意味着地球周而复始，在1月1日那天回到其公转轨道的起点，而这天也离地球最接近太阳的近日点仅有数天之遥。二种辉光之中，左侧的红色辉光是带着垂直线形结构的泛红极光，其起源是被太阳爆发推入地球大气的带电粒子。右侧的第二种名为稳定极光红弧的红色辉光，则是因为带电粒子流穿过地球大气所致。尽管两道辉光都是红色的，但它们的微小色差，可能是因为极光的辐射源是氧及氮，而较高的稳定极光红弧只有氧辐射。这幅主题影像，是在今年的1月1日摄于意大利的皮耶韦迪卡多雷镇附近。
宇宙门户: 随机APOD生成器
明日的图片: supernovas (plural)
