Why do stars turn into supernovas?

Between two huge gravitational forces, a star's always in flux. On one side, the star's gravity’s crushing force tries to squeeze the stellar material into the smallest and tightest ball possible. On the other side, the force of the tremendous heat and pressure from the nuclear fires burning at the star's center tries to push all that material outward.

When the star has burned out its nuclear fuel, the outward pressure is no longer able to counteract the gravity, and the star suddenly collapses. Imagine something one million times the mass of Earth collapsing in fifteen seconds.

The star's core’s collapse happens so quickly that it makes enormous shock waves that blow the outer part of the star into space at 20,000 kilometers per second (50 million miles per hour). A supernova is the biggest explosion known to man, the brilliant, dying gasp of a star that is five times more massive than our Sun.

Between two huge gravitational forces, a star's always in flux. On one side, the star's gravity’s crushing force tries to squeeze the stellar material into the smallest and tightest ball possible. On the other side, the force of the tremendous heat and pressure from the nuclear fires burning at the star's center tries to push all that material outward.

When the star has burned out its nuclear fuel, the outward pressure is no longer able to counteract the gravity, and the star suddenly collapses. Imagine something one million times the mass of Earth collapsing in fifteen seconds. The star's core’s collapse happens so quickly that it makes enormous shock waves that blow the outer part of the star into space at 20,000 kilometers per second (50 million miles per hour). A supernova is the biggest explosion known to man, the brilliant, dying gasp of a star that is five times more massive than our Sun.

Stars turn into supernovas because this is the process that they go through when they are about to die. The time will come when stars would start to lose its fuel. When the core becomes very heavy, the star will not be able to take the weight and the gravity anymore.

This can then lead to the supernova. Take note that not all types of stars will be able to become a supernova. The star has to be extremely large and it has to have enough mass in order to reach its status. It is possible for a star to become a supernova but not all stars are able to do that.