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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.
Tomorrow's picture: Enter the Helix
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NASA Web Site Statements, Warnings, and Disclaimers
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 March 18 Á LDN 1235: The Shark Nebula
- APOD: 2025 February 18 Á Thors Helmet versus the Seagull
- APOD: 2025 February 11 Á The Spider and the Fly
- A December Winter Night
- APOD: 2024 December 17 Á Near to the Heart Nebula
- APOD: 2024 November 25 Á The Horsehead Nebula
- The Elephant s Trunk in Cepheus