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Loading contentA dense, roughly spherical swarm of tens of thousands to millions of very old stars, tightly bound by gravity and orbiting in the halo of a galaxy. Globular clusters are among the oldest structures in the Universe, and their tightly packed, coeval stars make them benchmarks for stellar ages and the early history of the Galaxy.
Facts on this topic will be cited from these primary and reference sources.
Mission data, planetary science, space telescopes, and public-domain imagery.
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