Event horizon

Definition

The event horizon is the boundary surrounding a black hole beyond which nothing, not even light, can escape. It marks the point at which the gravitational pull becomes so strong that escape velocity exceeds the speed of light.

5 Must Know Facts For Your Next Test

1. The event horizon is also known as the point of no return for a black hole.
2. It is a theoretical surface and does not have physical structure.
3. The radius of the event horizon is known as the Schwarzschild radius.
4. Inside the event horizon, all paths lead to the singularity at the center of the black hole.
5. Event horizons are critical in understanding supermassive black holes and quasars.

Review Questions

• What happens to objects that cross the event horizon?
• What term is used to describe the radius of an event horizon?
• Why is it impossible for light to escape from within an event horizon?

Related terms

Singularity: The point at the center of a black hole where gravitational forces compress matter to infinite density.

Schwarzschild Radius: The radius defining the event horizon around a non-rotating black hole.

Gravitational Lensing: The bending of light around massive objects like black holes due to their intense gravitational field.