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===Inside the Event Horizon===

===Inside the Event Horizon===

What actually exists inside the event horizon of a black hole is a question physics is unable to answer. Some postulate that within the event horizon exists a point of zero (or nearly zero) volume but infinite energy density, a point sometimes referred to as a ''gravitational singularity,'' after the notion of a mathematical singularity (a term equaling infinity) in a field equation. Others suspect that infinite energy density is a physical impossibility, and that a black hole contains actual finitely-dense matter compressed into a [[degenerate matter|degenerate]] form, such as quark-degenerate matter. Since all black holes are surrounded by an event horizon which prevents any information or messages from leaving, all these theories are non-[[falsifiable]]; we can never be sure what the interior structure of a black hole is like.

What actually exists inside the event horizon of a black hole is a question physics is unable to answer. Some postulate that within the event horizon exists a point of zero (or nearly zero) volume but infinite energy density, a point sometimes referred to as a ''gravitational singularity,'' after the notion of a mathematical singularity (a term equaling infinity) in a field equation. Others suspect that infinite energy density is a physical impossibility, and that a black hole contains actual finitely-dense matter compressed into a [[degenerate matter|degenerate]] form, such as quark-degenerate matter. Since all black holes are surrounded by an event horizon which prevents any information or messages from leaving, all these theories are non-[[falsifiable]]; we can never be sure what the interior structure of a black hole is like.

===Properties of Black Holes===

===Properties of Black Holes===