[1] 第三旋臂边缘的一颗蓝色行星上的碳基生物正在庆祝他们所在的行星又在该恒星系里完成了一次公转：

https://www.zhihu.com/question/39056333/answer/958411765

[2] en.wikipedia.org/wiki/Milky_Way#Spiral_arms

[3] 银河系制图参考：

https://astronomy.nju.edu.cn/xtzl/EN/index.html

https://www.nasa.gov/mission_pages/sunearth/news/gallery/galaxy-location.html

[4] For a photo see: "Sagittarius A*: Milky Way monster stars in cosmic reality show". Chandra X-ray Observatory. Harvard-Smithsonian Center for Astrophysics. January 6, 2003. Archived from the original on March 17, 2008. Retrieved May 20, 2012.

[5] Leong, Stacy (2002). "Period of the Sun's Orbit around the Galaxy (Cosmic Year)". The Physics Factbook.

[6] Carl Sagan. "In the vastness of space and the immensity of time, it is my joy to share a planet and an epoch with Annie." Cosmos.

与有荣焉。

图文 / 星与辰starstars

科学审核 /  苟利军

策划 / 黄京一  编辑 / 怀尘 

来源：中国国家天文

编辑：hxg