南半球的双子座流星雨

2021年12月16日

Geminids of the South
Image Credit & Copyright: Fefo Bouvier

Explanation: Fireflies flash along a moonlit countryside in this scene taken on the night of December 13/14 from southern Uruguay, planet Earth. On that night meteors fell in the partly cloudy skies above during the annual Geminid meteor shower. Frames recorded over a period of 1.5 hours are aligned in the composite image made with the camera facing south. That direction was opposite the shower’s radiant toward the north and so the Geminid meteor streaks appear to converge at an antiradiant below the southern horizon. The shower’s apparent radiant (and antiradiant) is just due to perspective though. As Earth sweeps through the dust trail of mysterious asteroid 3200 Phaethon, the dust grains that create the Geminid shower meteors are really moving along parallel tracks. They enter Earth’s atmosphere traveling at about 22 kilometers per second.

Tomorrow’s picture: Geminids of the North

南半球的双子座流星雨
影像提供与版权: Fefo Bouvier

说明: 在12月13/14日摄于地球乌拉圭南部的这片景观里，月光下的原野有闪烁生辉的萤火虫。而在同个夜晚当地的薄云天空中，每年一度的双子座流星雨洒向大地。在当地1.5小时期间用南向相机拍摄的多张相片，经过对齐后叠合出这幅影像。影像的视野背对位于北方的流星雨辐射点，所以流星痕看似都会聚在南方地平线下方的反辐射点。双子座流星雨视觉上的辐射点（或反辐射点），其实源自透视效应。因为，地球穿过神秘法厄同小行星（3200 Phaethon）的尘尾之时，以每秒22公里高速进入地球大气、成为双子座流星的尘埃微粒之迹线彼此平行。

明日的图片: Geminids of the North