- The Orion Arm is a minor spiral arm of the Milky Way Galaxy that is 3,500 light-years (1,100 parsecs) across and approximately 10,000 light-years (3,100 parsecs) in length, containing the Solar System, including Earth. It is also referred to by its full name, the Orion–Cygnus Arm (not to be confused with the outer end of the Norma Arm the Cygnus Arm), as well as Local Arm, Orion Bridge, and formerly, the Local Spur and Orion Spur.