Chemical traces in the atmospheres of stars are being used to uncover new information about a galaxy, known as the Gaia Sausage, which was involved in a major collision with the Milky Way billions of years ago.
![](https://3c1703fe8d.site.internapcdn.net/newman/csz/news/tmb/2018/galaxy.jpg)
Source:
https://phys.org/news/2019-05-chemistry-stars-gaia-sausage.html