The event horizon is the boundary in spacetime beyond which the gravitational pull of a black hole is so strong that nothing, not even light, can escape.

Gravitational time dilation is a consequence of the equivalence principle in general relativity, which states that the effects of gravity are indistinguishable from the effects of acceleration.

As an object approaches the event horizon of a black hole, time dilation becomes so extreme that it appears to slow down or even stop for an observer outside the black hole.

A singularity is a point in spacetime where the curvature of spacetime becomes infinite and the laws of physics break down.

A wormhole is a hypothetical tunnel-like structure in spacetime that connects two distant points in the universe, allowing for faster-than-light travel.

Gravitational lensing is the bending of light by the gravitational field of a massive object, such as a black hole or a galaxy cluster.

The ergosphere is the region of spacetime around a black hole where the gravitational forces are so strong that objects are forced to rotate with the black hole.

A black hole is a hypothetical object that is formed when a star collapses under its own gravity and becomes infinitely dense.

A binary black hole is a system of two black holes that orbit around each other.

A neutron star black hole is a hypothetical object that is formed when a black hole and a neutron star merge.

A binary neutron star is a system of two neutron stars that orbit around each other.

A black hole white dwarf is a hypothetical object that is formed when a black hole and a white dwarf merge.

A binary white dwarf is a system of two white dwarfs that orbit around each other.

A black hole planet is a hypothetical object that is formed when a black hole and a planet merge.

A binary planet is a system of two planets that orbit around each other.