Milky Way Arms May Be 10% Farther

Astronomers using NASA's Chandra X-ray Observatory and ESA's XMM-Newton measured distances to dust clouds via gamma-ray burst light echoes. The study in Astronomy & Astrophysics found the Outer and Outer Scutum-Centaurus arms are about 10% more distant than previously thought, potentially revising estimates of the galaxy's mass and structure.