Like most spiral galaxies, the Milky Way has a roughly spherical collection of stars at its center called the bulge. How the bulge formed has been a long-standing mystery, with many studies suggesting that it built up over time through multiple bursts of star formation.
![](https://scx1.b-cdn.net/csz/news/tmb/2020/1-newsurveyfin.jpg)
Source:
https://phys.org/news/2020-10-survey-star-formation-milky-central.html