What are the four main parts of a spiral galaxy?

Answer 1

The first part is a flat, rotating disk.

The second part is central, stellar bulge that is made of older stars and global clusters.

The third is a halo of stars.

And the last is the black hole in the center.

Hope this helps.

Answer 2

As the stars revolve around the center of the galaxy, they get closer and further away from each other at regular intervals. like a set of traffic lights they build up at the red light, then move out on the green light, as we all know not everyone makes it through the lights thus causing the build up again. I'm not suggesting giant celestial traffic lights, but that is the easiest way i could explain why they appear in a spiral formation.

Answer 3

The core (or center) and the spiral arms.