Short answers, pulled from the story.
The Orion Arm is a minor spiral arm of the Milky Way that contains the Solar System, including Earth. It spans roughly 3,500 light-years in width and approximately 20,000 light-years in length. It is also known as the Orion-Cygnus Arm or the Local Arm.
The Orion Arm is situated between the Carina-Sagittarius Arm and the Perseus Arm. The Solar System lies near the arm's inner rim, about halfway along its length, and is approximately 8,000 parsecs from the Galactic Center.
Scientists originally classified the Orion Arm as a minor spur between the Carina-Sagittarius and Perseus arms. Evidence presented in 2013, largely from the BeSSeL Survey, showed that its pitch angle and star formation rate are comparable to those of major spiral arms, leading researchers to call it reasonably the fifth feature of the Milky Way.
The BeSSeL Survey, or Bar and Spiral Structure Legacy Survey, analyzed the parallax and proper motion of more than 30 masers in high-mass star-forming regions near the Sun, with measurement accuracy as fine as 3%. Its findings suggested the Local Arm wraps less than a quarter around the Milky Way and may be a branch of the Perseus Arm or an independent arm segment, rather than a simple spur.
The Orion Arm contains Betelgeuse, Rigel, the three stars of Orion's Belt, and the Orion Nebula. It also holds numerous Messier objects, including the Pleiades (M45), the Beehive Cluster (M44), the Ring Nebula (M57), the Dumbbell Nebula (M27), and the Butterfly Cluster (M6).
The Local Bubble is a relative cavity in the interstellar medium of the Orion Arm. The Solar System resides within it, positioned close to the inner rim of the arm and roughly halfway along its length.