Astronomy Picture of the Day

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

November 21, 1995
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M42: Orion Nebula Mosaic
Credit: NASA, HST, C. R. O'Dell and S. K. Wong (Rice U.)

Explanation: The Great Nebula in Orion is one of the most interesting of all astronomical nebulae known. Here fifteen pictures from the Hubble Space Telescope have been merged to show the great expanse and diverse nature of the nebula. In addition to housing a bright open cluster of stars known as the Trapezium, the Orion Nebula contains many stellar nurseries. These nurseries contain hydrogen gas, hot young stars, proplyds, and stellar jets spewing material at high speeds. Much of the filamentary structure visible in this image are actually shock waves - fronts where fast moving material encounters slow moving gas. Some shock waves are visible near one of the bright stars in the lower left of the picture. The Orion Nebula is located in the same spiral arm of our Galaxy as is our Sun. It takes light about 1500 years to reach us from there.

Tomorrow's picture: M1: The Exploding Crab Nebula

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Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
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