Black holes are an important part of how astrophysicists make sense of the universe—so important that scientists have been trying to build a census of all the black holes in the Milky Way galaxy.
![](https://scx1.b-cdn.net/csz/news/tmb/2019/3-blackhole.jpg)
Source:
https://phys.org/news/2019-10-scientists-class-black-holes.html