An open cluster is a group of stars that are physically close to each other in space and share a common origin. These clusters typically contain a few dozen to a few thousand stars, which are held together by their mutual gravitational attraction. Open clusters are often found in the Milky Way galaxy and are relatively young, usually only a few million years old. Unlike globular clusters, which are tightly packed and older, open clusters have a more scattered appearance. They can be observed with binoculars or small telescopes and are often associated with regions of active star formation, such as nebulae.