Orion Arm

The Orion Arm, or Orion–Cygnus Arm, is a minor spiral arm of the Milky Way galaxy.^[2] It is of interest because the Solar System (including the Earth) is inside it. The spiral arm is some 3,500 light-years (1,100 parsecs) across and approximately 10,000 light-years (3,100 parsecs) in length.^[3]

Observed structure of the Milky Way's spiral arms^[1]

The Orion Arm is named after the Orion constellation, one of the most prominent constellations. It is seen in the Northern Hemisphere during winter and in the Southern Hemisphere during summer. Some of the brightest stars and most famous celestial objects are in the Orion Arm: Betelgeuse, Rigel, the stars of Orion's Belt and the Orion nebula. They are shown on the interactive map below.

The Orion Arm is between the Carina–Sagittarius Arm (toward the Galactic centre) and the Perseus Arm (toward the outside Universe). The Perseus Arm is one of the two major arms of the Milky Way. The Solar system is on the Orion spur, between the two longer adjacent arms Perseus and Carina-Sagittarius.^[4]

Inside the Orion Arm, the Solar System is close to the inner rim, in the Local Bubble (simple wiki link) Local Bubble (wiki link). It is about halfway along the Orion Arm's length, about 8,000 parsecs (26,000 light-years) from the Galactic centre.

The shape of the Orion Spur^[5]

Interactive map

The nearest nebulae and star clusters (clickable map)