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In the night sky: Orion
In the night sky: Orion

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A structural component of the Milky Way and other spiral galaxies, consisting of a thick, dense concentration of stars around the centre of the disc. Bulges are a common feature of spiral and lenticular galaxies. In the case of the Milky Way (and many other galaxies), the bulge is elongated to form a bar.

» Orion Glossary