Title: The Concept Of The Event Horizon
Course: Relativity > Section: Module 44: The Concept Of The Event Horizon

The Concept of the Event Horizon

The event horizon is a crucial aspect of black holes. It marks the limit beyond which nothing can escape the gravitational pull of the black hole. For an observer outside the event horizon, objects falling into a black hole appear to slow down as they approach, due to the effects of time dilation predicted by general relativity.

Example:

Imagine watching a friend fall into a black hole. As they approach the event horizon, they seem to slow down and their image fades away, redshifted (their light stretches to longer wavelengths) until they are no longer visible. However, your friend would encounter the event horizon without realizing it, and from their perspective, they would cross it normally, moving towards the singularity.

Summary