The boundary beyond which nothing, not even light, can escape from a black hole.

The region around a black hole where spacetime is curved so much that it causes objects to orbit the black hole.

The point at the center of a black hole where all matter is concentrated.

The region around a black hole where spacetime is flat and objects can move freely.

A point of infinite density and gravity.

A region of spacetime where the laws of physics break down.

A region of spacetime where time and space are reversed.

A region of spacetime where matter is compressed to its maximum density.

The radius of the event horizon of a black hole.

The radius of the singularity at the center of a black hole.

The radius of the region around a black hole where spacetime is curved so much that it causes objects to orbit the black hole.

The radius of the region around a black hole where spacetime is flat and objects can move freely.

The Schwarzschild radius is directly proportional to the mass of the black hole.

The Schwarzschild radius is inversely proportional to the mass of the black hole.

The Schwarzschild radius is independent of the mass of the black hole.

The Schwarzschild radius is proportional to the square of the mass of the black hole.

Thermal radiation emitted by a black hole due to quantum effects near its event horizon.

Radiation emitted by a black hole due to the gravitational collapse of matter.

Radiation emitted by a black hole due to the rotation of its accretion disk.

Radiation emitted by a black hole due to the evaporation of its singularity.

A process by which energy can be extracted from a black hole by throwing objects into it.

A process by which energy can be extracted from a black hole by rotating it.

A process by which energy can be extracted from a black hole by merging it with another black hole.

A process by which energy can be extracted from a black hole by evaporating its singularity.

The region around a black hole where spacetime is curved so much that it causes objects to orbit the black hole.

The region around a black hole where spacetime is flat and objects can move freely.

The region around a black hole where the laws of physics break down.

The region around a black hole where matter is compressed to its maximum density.

The closest orbit that a particle can have around a black hole without falling into it.

The closest orbit that a particle can have around a black hole without being torn apart by tidal forces.

The closest orbit that a particle can have around a black hole without being swallowed by the singularity.

The closest orbit that a particle can have around a black hole without being affected by the black hole's gravity.

A theorem that states that a black hole is completely characterized by its mass, angular momentum, and electric charge.

A theorem that states that a black hole has no hair, meaning that it has no distinguishing features other than its mass, angular momentum, and electric charge.

A theorem that states that a black hole has no event horizon.

A theorem that states that a black hole has no singularity.

A hypothesis that states that the singularity at the center of a black hole is hidden from view by the event horizon.

A hypothesis that states that the event horizon of a black hole is a smooth surface.

A hypothesis that states that black holes cannot form in nature.

A hypothesis that states that black holes can only form in pairs.

A paradox that arises from the combination of quantum mechanics and general relativity.

A paradox that arises from the combination of special relativity and general relativity.

A paradox that arises from the combination of quantum mechanics and special relativity.

A paradox that arises from the combination of classical mechanics and general relativity.

A paradox that arises from the combination of quantum mechanics and general relativity.

A paradox that arises from the combination of special relativity and general relativity.

A paradox that arises from the combination of quantum mechanics and special relativity.

A paradox that arises from the combination of classical mechanics and general relativity.

A correspondence between a certain type of black hole in five dimensions and a conformal field theory in four dimensions.

A correspondence between a certain type of black hole in four dimensions and a conformal field theory in three dimensions.

A correspondence between a certain type of black hole in three dimensions and a conformal field theory in two dimensions.

A correspondence between a certain type of black hole in two dimensions and a conformal field theory in one dimension.

A black hole that is rotating.

A black hole that is not rotating.

A black hole that has a singularity at its center.

A black hole that does not have a singularity at its center.

A black hole that has an electric charge.

A black hole that has a magnetic charge.

A black hole that has both an electric charge and a magnetic charge.

A black hole that has neither an electric charge nor a magnetic charge.