galactic disk

例句：

1. 1. The discovery of this planet is a significant milestone in the study of the cosmos.
   发现这颗行星是研究宇宙的一个重大里程碑。
2. 2.The galactic disk is a vast expanse of stars and gas that stretches across the Milky Way.
   银河盘面是横跨银河的一片广阔的恒星和气体区域。
3. 3.In the early days of space exploration, astronomers used telescopes to observe the galactic disk.
   在太空探索的早期，天文学家使用望远镜来观察银河盘面。