The name of the galaxy that contains Earth is the Milky Way galaxy. It is a barred spiral galaxy comprised of billions of stars, including our Sun, along with star systems, nebulae, and various forms of interstellar matter. The Milky Way is about 100,000 light-years in diameter and is estimated to contain 100 to 400 billion stars. It is part of a larger collection of galaxies known as the Local Group. The structure of the Milky Way features a central bulge surrounded by a disk with spiral arms, in which our solar system is located in one of the outer arms called the Orion Arm.