Everything in the world dies, even the stars. A supernova occurs when a star “dies.” A supernova is the explosion of a star. These explosions release enormous amounts of energy, an amount equivalent to a few octillion nuclear warheads or a million tons of TNT. A supernova will radiate more energy than our child will emit in his entire lifetime. Supernovae play a huge role in the galaxy by being a primary source of heavy elements in the universe. During the life of a large star, they create heavy elements in their core. When one of these stars explodes, it releases heavy elements into the galaxy. The elements then disperse and create new stars and the cycle continues all over again. Supernovae occur when a star can no longer resist the force of gravity and collapses. There are two types of supernovae. Type II supernovae have hydrogen absorption lines in their light spectrum. Type II supernovae occur in stars with masses much larger than our sun. They are an implosion-explosion event. During fusion, outward pressure is created to balance the inward pull of gravity. However, once the fuel runs out, the star will expand into a red supergiant. While the star is still a red supergiant, the core becomes hotter and denser. During this time multiple nuclear reactions occur, delaying the collapse of the nucleus. However, once the core runs out of fuel this time, it has nothing left to fuse and the core collapses. Implosions, or collapses, of the iron cores of massive stars are caused by extreme pressures. When the core collapses, the temperature will rise to over 100 billion degrees. The energy from the shattering of the iron will initially be overcome by gravity, but will bounce back through the layers of the star. When it reaches the hydrogen envelope of the star, it explodes and a shock wave occurs. Many heavy elements are released from the explosion and are dispersed throughout the galaxy to form new stars. Type I supernovae lack hydrogen in their line spectra. These types of supernovae show sharp peaks in their light curves, then gradually fade away. There are three subclasses of type I, Ia, Ib and Ic. In type Ia, the white dwarf star has a companion star in a binary system. The stars must be close enough to allow material from the red giant to flow into the white dwarf.