PTE考生目前最大的问题之一就是练习题缺乏。除了有限的基本官方书（PLUS，Testbuilder, OG）之外，就没有题了。很多英语基础不是很扎实的同学很难找到练习材料。墨尔本文波雅思PTE培训学校专门为墨尔本，悉尼PTE考生准备了适合PTE听力阅读练习的科学60秒。各位PTE同学可以练习PTE听力中的summarise spoken text和PTE口语中的retell lecture，练习记笔记技巧和复述。废话少说，下面开始：
Galaxy Gave Star Cluster the Boot
60秒科学节目（SSS）是科学美国人网站的一套广播栏目，英文名称：Scientific American – 60 Second Science,节目内容以科学报道为主，节目仅一分钟的时间，主要对当今的科学技术新发展作以简明、通俗的介绍，对于科学的发展如何影响人们的生活环境、健康状况及科学技术，提供了大量简明易懂的阐释。
If galaxies were high school lunchrooms, the star cluster named HVGC-1 would be a social pariah. This unpopular cluster has been kicked out of its galaxy and forced to wander the cosmos alone.
HVGC-1 stands for hypervelocity globular cluster 1. Its thousands of stars had been part of the M87 galaxy, about 50 million light-years away. But now the cluster is fleeing that galaxy at more than two million miles per hour. Researchers reported the discovery in the Astrophysical Journal Letters. [Nelson Caldwell et al, A Globular Cluster Toward M87 with a Radial Velocity < -1000 km/s: The First Hypervelocity Cluster]
Astronomers are not sure why HVGC-1 was exiled from M87. One theory suggests that gravitational interactions with a pair of supermassive black holes at the galaxy’s center could have kicked out the cluster. Most galaxies contain a single giant black hole. If M87 is the product of a merger of two galaxies, it might host two central black holes in a binary system, researchers say.
In fact, that same double black hole future might await the Milky Way when we collide with our neighboring galaxy, Andromeda, in a few billion years. At which point, some star cluster may find itself ejected from the Milky Way, just like the ostracized HVGC-1.