Satellite galaxies are smaller galaxies that orbit around larger galaxies, much like moons orbit planets. They are gravitationally bound to their host galaxy and can vary in size and composition. These smaller galaxies can provide valuable insights into the formation and evolution of larger galaxies. The Milky Way galaxy, for example, has several known satellite galaxies, including the Large Magellanic Cloud and the Small Magellanic Cloud. Studying these satellite galaxies helps astronomers understand the dynamics of galaxy interactions and the role of dark matter in the universe.