Supernova remnants are the remnants of massive stars that have exploded in a supernova event. These remnants consist of gas and dust that are ejected into space, creating beautiful nebulae and enriching the interstellar medium with heavy elements. The study of these remnants helps astronomers understand the life cycles of stars and the evolution of galaxies. As the material from the explosion expands, it interacts with the surrounding interstellar medium, leading to the formation of shock waves and new stars. Famous examples of supernova remnants include the Crab Nebula and Cassiopeia A, which provide valuable insights into the processes that govern stellar evolution and the dynamics of the universe.