What causes a massive star to explode as a supernova?

There are two ways for the change to happen, type 1 and type 2, both of which are described below.

Type 1a and Type 1b are the two sub-divisions into which this is further divided.

While Type Ib and Type Ic are somewhat similar to Type 2, having lost most of their outer hydrogen envelopes, their cores collapse similarly to Type 2. All of the stars in Type Ia blaze with equal brightness at their peaks.

On the basis of the light curve, it is further divided into type II-L and type II-P.

Following the explosion, the light from Type II-L supernovas decreases steadily, while the light from Type II-P supernovas first remains steady before gradually decreasing.

When a massive star runs out of nuclear fuel and is no longer able to support itself against gravity, it explodes as a supernova, causing a shockwave that then causes a powerful explosion.