Active galaxies are a type of galaxy that emits an unusually high amount of energy, often outshining their surrounding stars. This energy comes from a supermassive black hole at the center, which pulls in gas and dust. As this material spirals in, it heats up and emits radiation across the electromagnetic spectrum, including visible light, radio waves, and X-rays. There are different types of active galaxies, including quasars, blazars, and Seyfert galaxies. Quasars are among the brightest objects in the universe, while blazars are known for their intense and variable emissions. These galaxies provide valuable insights into the formation and evolution of the universe.