What is a singularity in the context of black holes?

In the context of black holes, a singularity refers to a point of infinite density. This concept arises from the equations of general relativity, which suggest that when a massive star collapses under its own gravity, it can compress matter into an extremely small area. At this point, the gravitational forces become so intense that they lead to a breakdown of conventional physics as we understand it, resulting in what is termed a singularity.

At the singularity, both the curvature of space-time and the density of matter become infinite, leading to the notion that all the mass of the black hole is concentrated at a single point. This is significant because it poses challenges for our understanding of physics, especially in how we integrate quantum mechanics with general relativity. While regions of space-time curvature and event horizons are crucial when discussing black holes, the singularity itself is defined specifically by its characteristic of infinite density.