In the universe, the stars evolution differently according to their type. Some stars, like our Sun, will die in a peaceful way and without exploding, will finish its days being white dwarfs of about 10 000 km of diameter. But, other ones, like the blue giants, will finish into an enormous explosion named supernova.
Supernovas are classified in different types:
One of them is the Ia type. This supernovas are caused by a white dwarf which has a companion. This happens in binary systems. This white dwarf, which shines only because of its high temperature, what it does is that it steels material in big quantities from its companion. The problem will be that this dwarf can’t contain all the material of its star companion, for this reason, when the white dwarf will arrive to 1,4 solar masses, without the capacity to retain more the energy, it will explode without leaving any prove of its existence. The unique trace of its existence will be the light that it created during its last instances of existence. This light, the big messenger of the universe, arrives to us after many time, which depends of the distance from us when the dwarf star exploded. This type of supernovas are the most frequent, and this is good, because it permits to us calculate distances between galaxies using different scientific methods.
Another type, and maybe the most known by everybody, is the Ib. This type is formed due to a giant star which collapses into its own weight. This collapse is due to the fusion that takes place in the interiors of stars. In this process, it fusions the different elements situated in the star. In the biggest of them, the nuclear fusion arrives to create iron, but this element, because of being a very heavy element, consumes energy instead of producing it. For this reason, the star collapses in questions of seconds, producing this big explosion of which I’ve talked before. In the moment during which the star collapses, the material that the star created fusions during its last moments of live, creating some precious materials that we value a lot nowadays, such as gold or platinum. Afterwards, in the collapse, a neutron star will form, which is a very dense celestial body, or, worse, a dark hole.
Although here I’ve named only two types of supernovas, it doesn’t mean that they are the only types of them, there are more. For example there are the types Ic, IIn, GRB-SNe, superluminescent supernovas, etc.;but that I haven’t named due to the small variations from the types Ia and Ib.