Astronomers may have spotted a new spiral arm of the Milky Way galaxy

By Leah Crane

Astronomers may have found part of a never-before-seen arm of the Milky Way galaxy. This huge stream of gas – named Cattail because of its long, thin shape – is the largest and most distant gas filament ever spotted in our galaxy.

Keping Qiu at Nanjing University in China and his colleagues found one end of Cattail using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China. They then searched data from the HI4PI survey, an all-sky search for hydrogen gas, …