好友之间的星系

2021年11月06日

The Galaxy Between Two Friends
Image Credit & Copyright: Martin Lefranc

Explanation: On an August night two friends enjoyed this view after a day’s hike on the Plateau d’Emparis in the French Alps. At 2400 meters altitude the sky was clear. Light from a setting moon illuminates the foreground captured in the simple vertical panorama of images. Along the plane of our Milky Way galaxy stars of Cassiopeia and Perseus shine along the panorama’s left edge. But seen as a faint cloud with a brighter core, the Andromeda galaxy, stands directly above the two friends in the night. The nearest large spiral galaxy, Andromeda is about 2.5 million light-years beyond the stars of the Milky Way. Adding to the evening’s shared extragalactic perspective, the fainter fuzzy spot in the sky right between them is M33, also known as the Triangulum galaxy. Third largest in the local galaxy group, after Andromeda and Milky Way, the Triangulum galaxy is about 3 million light-years distant. On that night, the two friends stood about 3 light-nanoseconds apart.

Tomorrow’s picture: cosmic spirograph

好友之间的星系
影提像供与版权: Martin Lefranc

说明: 在今年8月的某个夜晚，二位好友在法国阿尔卑斯山的d’Emparis台地健行之后，共赏这片景观。于他们所在2,400公尺高的地点，当时的天空很澄澈。而如这幅直竖的全景影像所示，落月的月华照亮了影像的前景。仙女座及英仙座方向的银河系盘面繁星，在影像左缘附近绽放光芒。带着亮核的云雾状仙女大星系（M31），则在这对友人的头顶上。仙女大星系是离我们最近的大螺旋星系，近在银河恒星后方约2百50万光年远之处。在这片河外景观里，二人之间的暗淡光斑为三角大星系（M33）。在我们所在的本星系群里，离我们约3百万光年远的三角大星系，是排名在仙女大星系和银河系之后的第三大星系。在这个夜晚，这二位好友当时的间距约为3光奈秒。

明日的图片: cosmic spirograph