这个球状星团直径约为150光年，由1000万颗星星密集组成，它的年龄远远大于太阳。
Some 150 light-years in diameter, the cluster is packed with about 10 million stars much older than the Sun.
由于其中最古老的球状星团中最古老的成员星年龄有100亿年，天文学家知道，这一系统已经相聚很久了。
Astronomers know the system has been around for a while because the oldest stars in a few of its ancient globular clusters are about 10 billion years old.
介绍了白矮星宇宙纪年学研究的基本原理及其在银盘、球状星团、疏散星团以及银晕年龄确定方面的应用现状。
We also describe the basic principle of White Dwarf cosmochronology and its application in defining the age of the Galactic disk, globular clusters, open clusters and Galactic halo.
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