The Point of No Return

The event horizon defines the black hole's boundary and raises profound questions:

• It is not a surface but a mathematical boundary where escape velocity equals light speed
• The Schwarzschild radius determines the event horizon's size based on mass
• Time dilation makes falling objects appear to freeze at the horizon from the outside
• The falling observer crosses the horizon without noticing, but all future paths lead inward
• The no-hair theorem states black holes have only three properties: mass, charge, and spin

The event horizon is where classical physics meets its limits. What happens beyond it may require a theory of quantum gravity that does not yet exist.