What Is the Milky Way?

课文

1. The Milky Way is our home galaxy—a vast, rotating disk of over 100 billion stars.

   银河系是我们的家园星系——一个拥有上千亿颗恒星的巨大旋转盘状结构。

2. It looks like a hazy band of light across the night sky because we see it edge-on from inside.

   它在夜空中呈现为一条朦胧光带，因为我们正从内部侧向观测它。

3. Our Solar System sits about 27,000 light-years from the galaxy’s dense, star-packed center.

   太阳系位于距银河系致密、恒星密集的中心约2.7万光年处。

4. Most stars, including the Sun, orbit the galactic center once every 225–250 million years.

   包括太阳在内的大多数恒星，每2.25亿至2.5亿年绕银河系中心公转一周。

5. A supermassive black hole named Sagittarius A* lives at the very heart of the Milky Way.

   银河系核心处坐落着一个名为人马座A*的超大质量黑洞。

6. Dark matter makes up about 90% of the galaxy’s total mass, though we cannot see it directly.

   暗物质约占银河系总质量的90%，但我们无法直接观测到它。

7. Spiral arms—like the Orion Arm where Earth resides—contain young stars and glowing gas clouds.

   旋臂（如地球所在的猎户臂）包含年轻恒星和发光气体云。

8. The Milky Way is slowly merging with the smaller Andromeda Galaxy, a process that will take billions of years.

   银河系正缓慢与较小的仙女座星系合并，这一过程将持续数十亿年。

9. Radio telescopes help map its structure by detecting invisible hydrogen gas emissions.

   射电望远镜通过探测不可见的氢气辐射来绘制其结构。

10. From outside, astronomers believe it would look like a bright white spiral with soft blue arms.

    天文学家认为，若从外部观察，银河系将呈现为一个明亮的白色漩涡，伴以柔和的蓝色旋臂。