The Milky Way is the galaxy which contains our Sun. Our Sun is located within one of the spiral arms. Our galaxy is a collection of stars and interstellar dust. This dust/matter known as a nebula is the birthplace of stars. gravity is the force which pulls this matter together. The average distance between stars in our part of the galaxy is 5 light-years. A light-year measures distances between interstellar objects (the distance light travels in one year).