There’s a whole bunch of different types of supernovae: Type Ia, Type Ib, Type Ic, and Type II. I am not going to talk about Type Ib and Type Ic because they’re variants of Type II and thus really boring. Type Ia are kind of interesting but the ones I really want to talk about today are Type II supernovae, which are what everyone thinks of as a “classical” supernovae. To make a Type II supernova you take a really, really big star – eight or nine solar masses is the minimum limit – let it chew through its supply of hydrogen through nuclear fusion over a few hundred million years (the bigger a star, the shorter its lifespan) and then wait for the fireworks to start.