Galactic Dynamics -

: These are not permanent "arms" but density waves where stars and gas momentarily slow down, triggering star formation.

: Many galaxies, including our own, have a central bar that funnels gas toward the center, feeding the central black hole. 2. The Galactic Halo & Bulge Galactic Dynamics

: Visible matter cannot explain observed orbital speeds. A massive, invisible dark matter halo is required to keep galaxies from flying apart. Key Dynamical Components 1. The Galactic Disk : These are not permanent "arms" but density