Structure of a simple Black Hole

In fact, we do not really know what the inside of a black hole is like. Describing the characteristics of the structure of a black hole still remains one of the challenges of modern relativistic astrophysics.

The Schwarzschild radius is the radius at which the escape velocity equals the speed of light.

The surface of the sphere of radius equal to the Schwarzschild radius is called the event horizon. We on the outside of the black hole cannot learn anything about any event taking place within the event horizon, and thus we can think of it as the "surface" of the black hole.

At the center of the black hole lies a singularity, that is, a region where the current laws of physics break down because the circumstances are so extreme.

Note that the Schwarschild radius scales with the mass of the black hole. The Schwarzschild radius of a 1 solar mass black hole is 3 x 105 cm.

According to Roger Penrose's Principle of Cosmic Censorship, the fact that the laws of physics break down inside the event horizon has no impact on the physics outside the black hole (so we needn't worry about the failure of our current physics too much!?).

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