Disk

Definition

The disk of the Milky Way Galaxy is a flattened region that contains most of the galaxy's stars, gas, and dust. It is characterized by its spiral structure and significant star formation activity.

5 Must Know Facts For Your Next Test

1. The disk of the Milky Way contains both young and old stars, with younger stars typically found in the spiral arms.
2. It has a diameter of about 100,000 light-years and a thickness of roughly 1,000 light-years.
3. The disk is primarily composed of hydrogen and helium gas along with interstellar dust.
4. Star formation occurs predominantly in the disk's spiral arms due to higher concentrations of gas and dust.
5. The Sun is located approximately 26,000 light-years from the center of the Milky Way within one of its spiral arms.

Review Questions

• What types of stars are commonly found in the disk of the Milky Way?
• How large is the diameter and thickness of the Milky Way's disk?
• Why does star formation primarily occur in the spiral arms of the Milky Way?

Related terms

Spiral Arms:

Regions within the disk that have higher concentrations of stars, gas, and dust where star formation happens actively.

Halo:

A roughly spherical region surrounding the disk containing older stars, globular clusters, and dark matter.

Bulge:

The central spherical component at the core of the galaxy containing older stars and exhibiting little star formation activity.