Illustration of our galaxy, the Milky Way seen from above, with the arms and the central bar in their approximate known locations. There are four major arms and one arm fragment (Orion-Cygnus or Local) where the Sun is found. In the annotated version of this image, the yellow dot indicates the position of the Solar System about 25000 ly from the galactic core. The Norma and Outer arms are in fact the same, but the two names refer to different parts of it. The same is true of the so-called 3kpc (3 kilo-parsec) arm, which further out becomes the Perseus arm.