水星凌日

2019 December 2

Mercury Crosses a Quiet Sun
Video Credit: NASA, SDO, NASA’s Science Visualization Studio; Music: Gustav Sting (Kevin MacLeod) via YouTube

Explanation: What’s that black dot crossing the Sun? The planet Mercury. Mercury usually passes over or under the Sun, as seen from Earth, but last month the Solar System’s innermost planet appeared to go just about straight across the middle. Although witnessed by planet admirers across the globe, a particularly clear view was captured by the Solar Dynamics Observatory (SDO) in Earth orbit. The featured video was captured by the SDO’s HMI instrument in a broad range of visible light, and compresses the 5 1/2 hour transit into about 13 seconds. The background Sun was unusually quiet — even for being near Solar Minimum — and showed no sunspots. The next solar transit by Mercury will occur in 2032.

水星凌日
影像来源: NASA, SDO, NASA’s Science Visualization Studio; 音乐：Gustav Sting (Kevin MacLeod) via YouTube

说明：那个正在飞掠太阳的黑点是什么？是水星。从地球上看，水星通常是从太阳上方或下方掠过，但上个月，这颗太阳系最内侧的行星似乎正好从太阳中央径直掠过。尽管世界各地的行星观测者都观赏到了这次凌日现象，但地球轨道上的太阳动力学观测台（SDO）捕捉到了一幅特别清晰的景象。这幅精彩的视频是由太阳动力学观测台的HMI相机在多个可见光波段下拍摄的，它将五个半小时的凌日过程压缩到约13秒。影像背景中的太阳异常平静，即使在临近太阳活动极小期时，也没有出现太阳黑子。下一次水星凌日将发生在2032年。