This is old news from 2019 but important to note for educational purposes. The distribution of stars in the outer regions of the Milky Way galaxy deviates from a flat disk shape. The conclusion [1] was based on the distances to 1339 pulsating stars known as “classical Cepheids” which are 100000 times brighter than the Sun.
[1] Nature article https://doi.org/10.1038/s41550-018-0686-7
Earlier blogposts on Milky Way
What is the name of the super-massive black hole at the center of Milky Way?
Suresh Emre
Renaissance Universal 