Galaxies tend to clump together in clusters.

星系往往聚集形成星团。

They turned their telescopes toward other nearby galaxies.

他们把望远镜转向附近的其他星系。

This has led scientists to speculate on the existence of other galaxies.

这就使得科学家推测还有其他星系存在。

To explain this, they hypothesize that galaxies must contain a great deal of missing matter which cannot be detected.

为了解释这一点，他们假定银河系一定包含了大量无法探测到的不明物质。

Only galaxies with a spherical bulge—like component appear to accommodate supermassive black holes.

只有拥有球形膨胀物质的星系才可能容纳超大质量的黑洞。

Our galaxy is so huge that dozens of lesser galaxies scamper about it, like moons orbiting a giant planet.

我们的银河系实在庞大，吸引着数十个较小的星系环绕着它奔跑，恰似环绕巨大行星旋转的卫星。

These galaxies may constitute an answer to the long-standing puzzle of the missing baryonic mass in the universe.

这些星系可能为宇宙中长期存在的缺少重子质量这一谜题提供了答案。

Over billions of years, the gas was compressed by gravity into galaxies, stars, plants and eventually, even humans.

在数十亿年的时间里，这些气体被引力压缩成星系、恒星、植物，最终甚至变成了人类。

Until recently most astronomers believed that the space between the galaxies in our universe was a near-perfect vacuum.

直到最近，大多数天文学家都认为我们宇宙中星系之间的空间是近乎完美的真空。

In addition to conventional galaxies, the universe contains very dim galaxies that until recently went unnoticed by astronomers.

除了传统的星系，宇宙中还有一些非常暗淡的星系，直到最近才被天文学家发现。

The amount of "intergalactic rainfall" into some of these galaxies has been enough to double their mass in the time since they formed.

在这些星系中，“星系间降雨”的数量足以使它们的质量在形成的时间内翻倍。

Because these galaxies' mass is spread out over larger areas, they have far fewer stars per unit volume than do conventional galaxies.

因为这些星系的质量分布在更大的区域，它们每单位体积的恒星数量比传统星系要少得多。

Nearly all astronomical objects in space emit radio waves, whether nearby stars, objects in far away galaxies, they all give off radio waves.

太空中几乎所有的天体都发射无线电波，无论是附近的恒星，还是遥远星系中的天体，它们都会发射无线电波。

Bille and his team work with an optical instrument called an active mirror—a device used in astronomical telescopes to spot newly emerging stars and far distant galaxies.

比尔和他的团队使用一种被称为“活动镜”的光学仪器，这是一种在天文望远镜的种类中用来发现新出现的恒星和遥远星系的仪器。

Recent findings lend strong support to the theory that a black hole lies at the center of the Milky Way and of many of the 100 billion other galaxies estimated to exist in the universe.

最近的发现有力地支持了这样一种理论，即银河系中心，和宇宙中估计存在的1000亿个其他星系中的许多里有一个黑洞。

This orthodox view of the universe is now being challenged by astronomers who believe that a heavy "rain" of gas is falling into many galaxies from the supposedly empty space around them.

这种正统的宇宙观现在正受到天文学家的挑战。天文学家认为，一场巨大的气体“雨”正从星系周围所谓的空无一物的空间落入许多星系中。

The extension of astronomy from visible light to radio waves to x-rays and gamma rays never failed to lead to the discovery of unusual objects such as radio galaxies, quasars, and pulsars.

从可见光扩展到无线电波，再到 X 射线和伽马射线，天文学总是会发现不寻常的物体，如射电星系、类星体和脉冲星。

This law is known to hold true for galaxies at a distance of at least several billion light years.

这个定律被普遍认为同样适用于至少数十亿光年之远的星系。

Astronomers have long speculated that the missing baryonic mass might eventually be discovered in intergalactic space or as some large population of galaxies that are difficult to detect.

天文学家长期以来都在推测，最终可能会在星际空间或者是在难以探测的大量星系中发现丢失的重子质量。

Cobe is designed to see just the biggest structures, but astronomers would like to see much smaller hot spots as well, the seeds of local objects like clusters and superclusters of galaxies.

Cobe 的设计只是为了观测最大的结构，但天文学家们也希望看到更小的热点，即星系团和超星系团等局部天体的种子。

Jerusalem bells, galaxies and stardust.

耶路撒冷的钟声，星系和星尘。

Large galaxies grow by eating small ones.

大星系靠吃掉小星系来成长。

Which came first, black holes or galaxies?

是先有黑洞呢？还是先有星系？

But elliptical galaxies seem to be simpler.

但椭圆星系似乎更简单。

Still, elliptical galaxies can be very large.

但椭圆星系可以非常巨大。

Of those galaxies 17 are new discoveries.

它们当中有17个是新发现的星系。

If two galaxies merge, so should their black holes.

如果两个星系合并，那么它们的黑洞也会合并。

Without it, galaxies and clusters of galaxies should fly apart.

如果没有，星系及星系群应该会分崩离析。

These galaxies were often the brightest of the galaxies within their own groups.

这些星系是它们各自的群中最亮的。