Some, called active galaxies, pour out far more energy than normal ones.

有一些被称为活动星系的星系，它们释放出的能量比正常星系多得多。

Our black hole is quiescent, that is, not actively feeding, so we're not an active galaxy.

我们的黑洞是静止的，也就是说，我们不是一个活跃的星系。

And that's what powers active galaxies!

这就是活跃星系的动力！

How could they power active galaxies, the brightest objects in the Universe? ”

它们是如何给活动星系——宇宙中最亮的物体——提供能量的呢？”

Spirals, ellipticals, irregulars, peculiars, active galaxies… in many clusters, a huge elliptical galaxy sits right at the very center.

螺旋星系、椭圆星系、不规则星系、特殊星系、活动星系… … 在许多星系团中，有一个巨大的椭圆星系就位于正中央。

Today you learned that active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter.

今天你学到了活跃的星系会释放出大量的能量，因为它们中心的超大质量黑洞会吞噬物质。

Astronomers gave them the generic name “active galaxies, ” and classified them into various subcategories depending on how they emitted their light, and what kind of spectra they had.

天文学家将它们命名为“活动星系”，并根据它们发出光的方式和光谱的类型将它们分为不同的子类。