Open Clusters are young, relatively small, and contain thousands of stars
There are two types of star clusters:
Globular Clusters are old, large, and contain hundreds of thousands of stars
If we assume all stars in the cluster were formed at roughly the same
time, we can use our theory of stellar evolution to estimate the ages
of clusters.
10 Million Years
600 Million Years
12 Billion Years
Star Clusters are important because they