Astronomy Picture of the Day——流星划过星系
Meteor Misses Galaxy
Image Credit: Aman Chokshi
Explanation: The galaxy was never indanger. For one thing, the Triangulum galaxy (M33), pictured, is much biggerthan the tiny grain of rock at the head of the meteor. For another, the galaxyis much farther away -- in this instance 3 million light years as opposed toonly about 0.0003 light seconds. Even so, the meteor's path took it angularlybelow the galaxy. Also the wind high in Earth's atmosphere blew the meteor'sglowing evaporative molecule train away from the galaxy, in angular projection.Still, the astrophotographer was quite lucky to capture both a meteor and agalaxy in a single exposure -- which was subsequently added to two other imagesof M33 to bring up the spiral galaxy's colors. At the end, the meteor was gonein a second, but the galaxy will last billions of years.
流星划过星系
这个星系从未身处危险之中。首先，在照片中，三角星座系（M33）比流星最前面的微小岩石颗粒要大得多的多。其次，星系更加遥远，其距离地球为300万光年，与之截然不同，流星距离地球仅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色彩。流星在一秒钟内就消失了，而三角座星系将在这存在数十亿年。
参考文献：
https://apod.nasa.gov/apod/image/1904/M33Meteor_Chokshi_2000.jpg
近期文章：
Astronomy Picture of the Day——N11：大麦哲伦星系内的星云