64: The Local Arm of the Milky Way and the Sun's Changing Place. Dr. Ken Croswell discusses new revelations about the Milky Way, a spiral galaxy. The Sun is in the local arm, also called the Orion arm

The Local Arm of the Milky Way and the Sun's Changing Place. Dr. Ken Croswell discusses new revelations about the Milky Way, a spiral galaxy. The Sun is in the local arm, also called the Orion arm, which is a vigorous star nursery containing the Orion Nebula. Previously considered a minor spur, the local arm is now known to be substantial, extending at least 26,000 light-years. Observations rely on maser parallaxes measured by radio telescopes and precise data from the optical Gaia spacecraft. The Sun is not a permanent resident of this arm.