But there are still many unanswered questions. The halo that surrounds our Galaxy is one mystery region... The centre of the Galaxy hides even more secrets.

"Who Discovered the Galaxy - Presidential Address – 1985", Heather Couper, British Astron. Assoc. Journal V. 96, No. 5 (1986), p. 293

https://adsabs.harvard.edu/full/1986JBAA...96..284...[adsabs.harvard.edu]