Illustration of a massive star going supernova, which means it is creating an immensely powerful explosion, which for a brief moment is brighter than the entire light of the galaxy. This kind of explosion happens at the end of the life of a massive star. The core fuses heavier elements from lighter ones, and this releases energy outwards. This energy counters the gravity of the star. When the core consists of iron, it cannot produce heavier elements, so the gravity from the star crushes the core into a neutron star, or a black hole. The star first implodes, and then explodes, sending more of the matter the star is made of, out into space. This matter may form into smaller stars one day.