Star clusters are groups of stars that are bound together by gravitational forces. They come in two main types: open clusters and globular clusters. Open clusters are relatively young groups of stars, typically containing fewer than a few thousand stars. They are often found in the spiral arms of galaxies like our own Milky Way. Open clusters are important for studying stellar evolution, as all of the stars in the cluster were formed from the same molecular cloud at roughly the same time. Globular clusters, on the other hand, are much older and contain tens of thousands to millions of stars. They are typically found in the halos of galaxies and have a more spherically symmetric distribution. Globular clusters are thought to be some of the oldest objects in the universe, and studying them can provide insights into the early stages of galaxy formation. Overall, star clusters are important for understanding the formation and evolution of stars and galaxies, and studying them can provide valuable information about the history and dynamics of the universe.