Orion Arm

This article is about the galactic arm of the Milky Way Galaxy. For the stars which form the arm of the Orion asterism, see Orion (constellation). For other uses, see Arm of Orion (disambiguation).
Figure 1.The observed structure of the Milky Way's spiral arms[1]

The Orion Arm, also known as the Orion–Cygnus Arm, is a minor spiral arm within the Milky Way Galaxy spanning 3,500 light-years (1,100 parsecs) in width and extending roughly 20,000 light-years (6,100 parsecs) in length.[2] This galactic structure encompasses the Solar System, including Earth. It is sometimes referred to by alternate names such as the Local Arm or Orion Bridge, and it was previously identified as the Local Spur or the Orion Spur. It should not be confused with the outer terminus of the Norma Arm, known as the Cygnus Arm.

  1. ^ See the "Spiral Arms" part of this NASA animation for details.
  2. ^ Xu, Ye; Reid, Mark; Dame, Thomas; Menten, Karl; Sakai, Nobuyuki; Li, Jingjing; Brunthaler, Andreas; Moscadelli, Luca; Zhang, Bo; Zheng, Xingwu (28 September 2016). "The local spiral structure of the Milky Way". Science Advances. 2 (9): e1600878. arXiv:1610.00242. Bibcode:2016SciA....2E0878X. doi:10.1126/sciadv.1600878. PMC 5040477. PMID 27704048.