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Explanation: A dusty bright nebula contrasts dramatically with a dusty dark nebula in this Hubble Space Telescope image recorded shortly after December's orbital servicing mission. The nebula, cataloged as NGC 1999, is a reflection nebula, which shines by reflecting light from a nearby star. Unlike emission nebulae, whose reddish glow comes from excited atoms of gas, reflection nebulae have a bluish cast as their interstellar dust grains preferentially reflect blue starlight. While perhaps the most famous reflection nebulae surround the bright young stars of the Pleiades star cluster, NGC 1999's stellar illumination is provided by the embedded variable star V380 Orionis, seen here just left of center. Extending right of center, the ominous dark nebula is actually a condensation of cold molecular gas and dust so thick and dense that it blocks light. From our perspective it lies in front of the bright nebula, silhouetted against the ghostly nebular glow. New stars will likely form within the dark cloud, called a Bok globule, as self-gravity continues to compress its dense gas and dust. Reflection nebula NGC 1999 lies about 1500 light-years away in the constellation Orion, just south of Orion's well known emission nebula, M42.
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NASA Official: Jay Norris. Specific rights apply.
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& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: Orion - reflection nebula - bok globule
Publications with words: Orion - reflection nebula - bok globule
See also:
- APOD: 2024 January 31 Á Camera Orion Rising
- APOD: 2024 January 16 Á The Orion You Can Almost See
- The Light, the Dark, and the Dusty
- APOD: 2023 October 30 Á Reflections of the Ghost Nebula
- The Ghosts of Gamma Cas
- APOD: 2023 September 26 Á IC 4592: The Blue Horsehead Reflection Nebula
- NGC 7023: The Iris Nebula