Open clusters are groups of stars that are loosely bound by gravity and typically contain a few dozen to a few thousand stars. These stars usually formed from the same giant molecular cloud and are relatively young, often just a few million years old. Open clusters are found in the Milky Way and other galaxies, and they can be identified by their distinctive patterns in the night sky. Unlike globular clusters, which are tightly packed and contain older stars, open clusters have a more scattered appearance. Over time, the stars in an open cluster can drift apart due to gravitational interactions and the influence of nearby objects. Some well-known examples of open clusters include the Pleiades and the Hyades.