本文参考livescience文章，“the milky way's 'thick disk' is 2 billion years older than scientists thought ”，如有兴趣还可查阅原文。 如有侵犯版权还请告知，我们将在24小时内删除 Distant milky way halo rr lyrae stars in the next generation virgo cluster survey: Exploring the outer edge of our galaxy.
The Five Types of Cliffhangers — Ariele Sieling
