What is a galaxy? -- Where did galaxies come from? -- Looking at the Milky Way -- How big is the Milky Way galaxy? -- Where are the Milky Way's stars formed? -- What kinds of nebula are in our galaxy? -- What lies in the core of the Milky Way? -- How big is the galactic halo? -- Beyond the Milky Way -- What is the local group? -- Can galaxies collide? -- What is an active galaxy? -- How many galaxies are there?
Summary
Discusses our own Milky Way and discusses the nature and behavior of galaxies in general.