Examples

我们用肉眼是看不到河外星系的。

Extragalactic nebula is invisible to the naked eye.

星系

galaxy

河外星系。

Astronomy studies the motions and natures of celestial bodies, such as planets, stars and galaxies.

天文学研究天体的运动和性质，例如，行星、恒星和星系。

The biggest difference between galaxies is the huge variation in their appearance.

星系之间的最大不同就是其外观上的巨大差异。

"Extragalactic nebula" is a former name for "galaxy".

“外星云”是“星系”的曾用名。

We haven't even begun to map the many galaxies that we know exist.

我们甚至对我们已知的众多星系都还没有进行勘测。

A binary star is a system in which two stars revolve around each other.

双子星是两颗互相围绕对方旋转的星体组成的星系。