Where does Earth fit into the galactic picture?
The galaxy that contains Earth’s solar system is called the Milky Way. The Milky Way galaxy is about 80 thousand light years across. Its nucleus contains billions of old stars and maybe even a black hole. It has four spiral arms. Our solar system is located in the Orion arm of the galaxy, about 28 thousand light years from the center of the galaxy. The Milky Way is part of a cluster of galaxies known as the Local Group, and the Local Group is a part of a local supercluster that includes many clusters. Superclusters are seperated by extremely large voids of space, with very few galaxies in between.
