Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2001 December 10
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Globular Cluster M15
Credit: Haldan Cohn (Indiana U.) et al., WIYN, NOAO, NSF

Explanation: Stars, like bees, swarm around the center of bright globular cluster M15. This ball of over 100,000 stars is a relic from the early years of our Galaxy, and continues to orbit the Milky Way's center. M15, one of about 150 globular clusters remaining, is noted for being easily visible with only binoculars, having at its center one of the densest concentrations of stars known, and containing a high abundance of unusual variable stars and pulsars. The above image, taken in ultraviolet light with the WIYN Telescope, spans about 120 light years and shows the gradual increase in stars toward the cluster's center. M15 lies about 35,000 light years away toward the constellation of Pegasus. Recent evidence indicates that a massive black hole might reside as the center of M15.

Tomorrow's picture: Venus Half Shell

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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