Detail View: NASA Astronomy Picture of the Day Collection: Barnard's Loop Around Orion
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Title:
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Barnard's Loop Around Orion
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Explanation:
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Why is the belt of Orion [ http://www.daviddarling.info/encyclopedia/O/OrionsBelt.html ] surrounded by a bubble? Although glowing like an emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], the origin of the bubble, known as Barnard's Loop [ http://weblore.com/richard/barnard's_loop.htm ], is currently unknown. Progenitor hypotheses include the wind [ http://www-spof.gsfc.nasa.gov/Education/wsolwind.html ]s from bright Orion stars and the supernovas [ http://heasarc.gsfc.nasa.gov/docs/snr.html ] of stars long gone. Barnard's Loop [ http://www.seds.org/messier/xtra/ngc/b-loop.html ] is too faint to be identified with the unaided eye. The nebula [ http://eaa.iop.org/abstract/0333750888/5287 ] was discovered only in 1895 by E. E. Barnard [ http://astro.uchicago.edu/yerkes/virtualmuseum/Barnardfull.html ] on long duration film exposures. Orion's belt [ http://www.gb.nrao.edu/~rmaddale/Education/OrionTourCenter/belt.html ] is seen as the three bright stars across the center of the image, the upper two noticeably blue. Just to the right of the lowest star in Orion's belt [ http://www.astro.uiuc.edu/~kaler/sow/alnitak.html ] is a slight indentation in an emission nebula that, when seen at higher magnification [ http://antwrp.gsfc.nasa.gov/apod/ap040115.html ], resolves into the Horsehead Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap050321.html ]. To the right of the belt stars is the bright, famous, and photogenic Orion Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap040927.html ].
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Credit and Copyright:
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//www.ifa.hawaii.edu/~wang/gallery/gallery.html" >Copyright: W. H. Wang [ http://www.ifa.hawaii.edu/~wang/ ] (IfA, U. Hawaii [ http://www.ifa.hawaii.edu/ ])
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facet_when:
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1895
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facet_where:
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Goddard Space Flight Center (GSFC)
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facet_what:
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ALNITAK
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facet_when_year:
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1895
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original url:
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http://antwrp.gsfc.nasa.gov/apod/ap050420.html
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UID:
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SPD-APOD-ap050420
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