Which formed last: the visible halo, the galactic nucleus, or the disk? How do you know?
- PaulaLv 72 years ago
The disc formed last.
"The gas from halo mergers goes toward the formation of the central galactic components, while stars and dark matter remain in the galactic halo"
that's a quote from here. https://en.wikipedia.org/wiki/Galactic_halo#Format...
So that means halo is formed before the disc and the nucleus
next to form is the central bulge
"Within a billion years of a galaxy's formation, key structures begin to appear. Globular clusters, the central supermassive black hole, and a galactic bulge of metal-poor Population II stars form."
that's a quote from here https://en.wikipedia.org/wiki/Galaxy#Evolution
So that leaves the disc to have been formed last.
- 2 years ago