Globular clusters are densely packed, spherical collections of stars that orbit the core of a galaxy as a single, gravitationally bound system. Unlike open clusters, which are younger and loosely grouped, globular clusters are made up of some of the oldest known stars in the universe—often over 10 billion years old. These clusters can contain hundreds of thousands to even millions of stars, all tightly gathered into a compact region of space. Most are found in the halo of our Milky Way and other galaxies, and their age and composition provide valuable clues about the early stages of galactic formation. Through a telescope, they often appear as glowing, fuzzy balls of light, with their brightest stars resolvable around the edges.

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