Globular cluster

Definition

A globular cluster is a spherical collection of stars that orbits the core of a galaxy. These clusters are tightly bound by gravity, making them densely packed with stars, often containing hundreds of thousands to millions of stars.

5 Must Know Facts For Your Next Test

1. Globular clusters are among the oldest known objects in the universe, often containing stars that are over 10 billion years old.
2. They primarily consist of Population II stars, which are metal-poor and older than Population I stars.
3. The Milky Way galaxy contains about 150 to 200 known globular clusters.
4. Unlike open clusters, globular clusters have a more spherical shape and can contain far more stars.
5. Globular clusters provide key insights into the early stages of galactic formation and evolution.

Review Questions

• What distinguishes a globular cluster from an open cluster?
• Why are globular clusters considered important for understanding the early universe?
• How do the ages of stars in globular clusters compare to those in other parts of a galaxy?

Related terms

Open Cluster: A group of up to a few thousand loosely bound stars formed from the same molecular cloud and relatively young in age.

Population II Stars:

Older, metal-poor stars found primarily in globular clusters and the halo of galaxies.

Milky Way Galaxy:

The spiral galaxy that contains our Solar System, home to both open and globular star clusters.