What is the Orion Arm and how does it relate to the Solar System?
The Orion Arm carries the name of a winter constellation visible from both hemispheres. Scientists place the Solar System near the inner rim of this spiral structure.
Questions about Orion Arm
Short answers, pulled from the story.
When did evidence change the classification of the Orion Arm in 2013?
Evidence presented in June 2013 challenged that classification with data suggesting independence. Dave Finley wrote about Earth's neighborhood getting more respect in 2013 when new evidence emerged.
How long and wide is the Orion Arm compared to other galactic structures?
Measurements indicate the arm spans roughly twenty thousand light years in length and three thousand light years wide. The distance from the Galactic Center sits at approximately twenty-six thousand light years.
Which Messier objects are located within the boundaries of the Orion Arm?
The Butterfly Cluster known as M6 appears among the many Messier objects within this structure. The Pleiades cluster designated as M45 shines brightly for observers on Earth alongside the Orion Nebula labeled M42.
Why do researchers consider the Orion Arm independent rather than a spur?
Researchers mapped stellar density using Gaia DR2 data for stars aged about one billion years. These findings suggest the segment wraps around less than a quarter of the Milky Way galaxy.