Hence it is considered that a galactic year can be based on to institute an ideal geologic time scale in which a galactic year is an era.

银河年是建立理想地质年代表的基础，每一个银河年就是一个代。

youdao

Hence it is considered that a galactic year can be based on to institute an ideal geologic time scale in which a galactic year is an era.

银河年是建立理想地质年代表的基础，每一个银河年就是一个代。

youdao