Transcript: The advance evolutionary stages of a massive star represent a crescendo of nuclear activity. After millions of years of creating helium from hydrogen by the fusion process, each of the late stages of fusion take less than a thousand years, the creation of carbon, neon, and oxygen. The creation of iron from silicon and sulfur takes only a few days, and then with iron, the most stable element, there is no more energy support and the core collapses. The core collapses at about a quarter the speed of light. The density rises almost instantaneously by a factor of a million, and a volume the size of the Earth is squeezed down to a size of about fifty kilometers. This all takes place in only a few seconds. Protons and electrons are forced to coalesce producing neutrons and a flood of neutrinos that flee the scene and emit 1047 watts. The luminosity of a supernova in the instant of the core collapse and just after exceeds the luminosity of the entire universe.