Sun in the Milky Way NASA Key Ring

Sun in the Milky Way NASA . Using infrared images from NASA's Spitzer Space Telescope, science have discovered that the Milky Way's elegant spiral structure is dominated by just two arms wrapping off the ends of a central bar of stars. The galaxies major arms consist of the highest densities of both young and old stars; the minor arms are primarily filled with gas and pockets of star-forming activity.