Here's why:
* Supernova: These stars go through a spectacular explosion called a supernova at the end of their lives.
* Core Collapse: During the supernova, the star's core collapses under its own gravity.
* Black Hole Formation: If the core is massive enough (more than about 3 times the mass of our Sun), it collapses so intensely that it creates a singularity, a point of infinite density. This singularity is surrounded by an event horizon, a boundary from which nothing, not even light, can escape. This is a black hole.
