The Cygnus Loop is a large supernova remnant located in the constellation Cygnus. It is approximately 1,000 light-years away from Earth and spans about 3 degrees in the sky, which is roughly six times the width of the full moon. The remnant is composed of glowing gas and dust, formed from the explosion of a massive star that occurred around 10,000 to 20,000 years ago. This structure is notable for its intricate filaments and bright regions, which are the result of shock waves interacting with surrounding interstellar material. The Cygnus Loop is also a rich source of cosmic rays and has been studied extensively by astronomers to understand the processes involved in stellar death and the evolution of the interstellar medium.