This line of reasoning underlies an exciting new theory of spiral-galaxy structure.
2
如果许多这样的链是在一个不同的旋转星系中产生的,那么恒星的分布将类似于在螺旋星系中观察到的分布。
If many such chains were created in a differentially rotating galaxy, the distribution of stars would resemble the observed distribution in a spiral galaxy.
3
星系主要分为三类:螺旋星系、椭圆星系和不规则星系。
Galaxies are classified into three main types: spiral galaxies, elliptical galaxies, and irregular galaxies.