Active galaxies are a type of galaxy that emits a significant amount of energy, often outshining their surrounding stars. This energy comes from a supermassive black hole at their center, which pulls in gas and dust, creating intense radiation as the material spirals in. These galaxies can be classified into different types, including quasars, blazars, and radio galaxies, based on their specific characteristics and the type of radiation they emit. The activity in these galaxies can lead to the formation of powerful jets and outflows that extend far beyond the galaxy itself. Active galaxies are important for understanding the evolution of galaxies and the role of black holes in the universe. Their study helps astronomers learn more about cosmic phenomena and the behavior of matter under extreme conditions.