The Milky Way is classified as a barred spiral galaxy. This means it has a flat, rotating disk with spiral arms and a central bar-shaped structure composed of stars cutting across its center. The spiral arms extend from the ends of this bar rather than directly from the central bulge
. More specifically, the Milky Way is often categorized as an Sb or Sbc type barred spiral galaxy, indicating it has moderately wound spiral arms and a noticeable central bulge, but not as tightly wound as Sa types or as loose as Sc types
. Key characteristics of the Milky Way as a barred spiral galaxy include:
- A disk about 100,000 light-years in diameter and roughly 1,000 light-years thick
- A central bar of stars across the galaxy’s core
- Spiral arms rich in gas and young stars where star formation is active
- A halo of older stars, star clusters, and dark matter surrounding the disk
Thus, the Milky Way fits within the large class of barred spiral galaxies, which make up about two-thirds of all spiral galaxies in the nearby universe
