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。
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.
有的漩涡星系长得和银河很像，有的星系则呈橄榄球般的椭圆形，还有的只是群星松散的排列，没有鲜明的形态。
Some spiral galaxies like our own, others elliptical in shape more like rugby balls and others just loose clumps of stars with no real defined shape.
相反的，他们只能局限于直接测量轨道上的物体：银河系中的气体，恒星，以及较远的卫星星系和星团。
Instead they are limited to directly measuring objects in orbit: the galaxy's gas and stars, as well as distant satellite galaxies and star clusters.
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