emission nebula

• 发射星云

emission nebula的用法和样例：

例句

1. The emission nebula's red color is caused by electrons recombining with protons to form hydrogen atoms.
   发射星云显现的红色是由质子再次与电子结合形成氢原子后形成。
2. Numerous red emission nebulas and blue reflection nebulas are visible throughout the image.
   在整张影像中，许多红色发射星云和蓝色反射星云清晰可见。