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|globular cluster |
A spherical mass made up of thousands to hundreds of thousands of densely packed stars of nearly the same age (typically very old). Globular clusters occupy the inner regions of a galactic halo and revolve around the nucleus of galaxies in highly elliptical orbits inclined to the disk of the spiral arms. There are approximately 150 of these clusters in the Milky Way. It is believed that globular clusters can provide information about the evolution and lifespan of stars. Compare open cluster.