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Explanation: The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the black indentation to the red emission nebula seen just to the right of center of the above photograph. The bright star near the center is located in the belt of the familiar constellation of Orion. The horse-head feature is dark because it is really an opaque dust cloud which lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will alter its appearance. The emission nebula's red color is caused by electrons recombining with protons to form hydrogen atoms. Also visible in the picture are blue reflection nebulae, which preferentially reflect the blue light from nearby stars.
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NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: nebula - Orion - absorption nebula - emission nebula - Horsehead Nebula
Publications with words: nebula - Orion - absorption nebula - emission nebula - Horsehead Nebula
See also:
- APOD: 2025 July 22 B A Double Detonation Supernova
- APOD: 2025 July 21 B Cats Paw Nebula from Webb Space Telescope
- APOD: 2025 July 16 B The Rosette Nebula from DECam
- APOD: 2025 July 5 B Ou4: The Giant Squid Nebula
- APOD: 2025 June 26 B The Seagull Nebula
- NGC 6164: A Dragon s Egg
- APOD: 2025 March 18 B LDN 1235: The Shark Nebula