流星划过星系
影像来源与版权:Aman Chokshi

说明:这个星系从未处于危险之中。首先,这幅影像中的三角星系(M33)比流星最前面的微小岩石颗粒要大得多。其次,星系遥远得多,在此情况下,其距离为300万光年,相反,流星则距离我们0.0003光秒。即便如此,流星的轨迹在星系下方成角度地移动。另外,在地球大气层的高空,在视角投影上看,恒星风将流星炽热的蒸汽分子链吹离星系。尽管如此,这位天文摄影师还是很幸运地在单次曝光中同时捕捉到一颗流星和一个星系,随后,将M33的其他两张照片叠加到这张照片中,以呈现出旋涡星系的颜色。最后,流星在一秒钟内消失了,但星系将持续存在数十亿年。
翻译:北京天文馆

Meteor Misses Galaxy
Image Credit & Copyright: Aman Chokshi

Explanation: The galaxy was never in danger. For one thing, the Triangulum galaxy (M33), pictured, is much bigger than the tiny grain of rock at the head of the meteor. For another, the galaxy is much farther away — in this instance 3 million light years as opposed to only about 0.0003 light seconds. Even so, the meteor’s path took it angularly below the galaxy. Also the wind high in Earth’s atmosphere blew the meteor’s glowing evaporative molecule train away from the galaxy, in angular projection. Still, the astrophotographer was quite lucky to capture both a meteor and a galaxy in a single exposure — which was subsequently added to two other images of M33 to bring up the spiral galaxy’s colors. At the end, the meteor was gone in a second, but the galaxy will last billions of years.
Astronomy Picture of the Day 04/30/2019