Charged black hole

A charged black hole is a black hole that possesses electric charge. Since the electromagnetic repulsion in compressing an electrically charged mass is dramatically greater than the gravitational attraction (by about 40 orders of magnitude), it is not expected that black holes with a significant electric charge will be formed in nature.

## Categories

The two types of charged black holes are Reissner–Nordström black holes (without spin) and Kerr–Newman black holes (with spin).

A black hole can be completely characterized by three (and only three) quantities:

* M – mass
* J – angular momentum
* Q – electric charge

Charged black holes are two of four possible types of black holes that have been found by solving Einstein's theory of gravitation, general relativity. The mathematical solutions for the shape of space and the electric and magnetic fields near a black hole are named after the persons who first worked them out. The solutions increase in complexity depending on which of the two parameters, J and Q, are zero (or not) (the mass M of a black hole could conceivably be tiny, but not zero). The four categories of solutions are given in the table below:

Black hole type  | Description  | Constraints

|
|

Schwarzschild  | has no angular momentum
and no electric charge  | J = 0  | Q = 0
Kerr  | does have angular momentum
but no electric charge  |  | Q = 0
Reissner–Nordström  | has no angular momentum but
does have an electric charge  | J = 0  |
Kerr–Newman  | has both angular momentum
and an electric charge  |  |

The solutions of Einstein's field equation for the gravitational field of an electrically charged point mass (with zero angular momentum) in empty space was obtained in 1918 by Hans Reissner and Gunnar Nordström, not long after Karl Schwarzschild found the Schwarzschild metric as a solution for a point mass without electric charge and angular momentum.

A mathematically-oriented article describes the Reissner–Nordström metric for a charged, non-rotating black hole. A similarly technical article on the Kerr–Newman black hole gives an overview of the most general known solution for a black hole, which has both angular momentum and charge (all the other solutions are simplified special cases of the Kerr–Newman black hole).

## See also

* Reissner–Nordström metric

## External links

* COSMOS - The SAO Encyclopedia of Astronomy - Black Hole

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Black holes

Types|

* Schwarzschild
* Rotating
* Charged
* Virtual
* Kugelblitz
* Primordial
* Planck particle

Size|

* Micro
* Extremal
* Electron
* Stellar
* Microquasar
* Intermediate-mass
* Supermassive
* Active galactic nucleus
* Quasar
* Blazar

Formation|

* Stellar evolution
* Gravitational collapse
* Neutron star
* Related links
* Tolman–Oppenheimer–Volkoff limit
* White dwarf
* Related links
* Supernova
* Related links
* Hypernova
* Gamma-ray burst
* Binary black hole

Properties|

* Gravitational singularity
* Ring singularity
* Theorems
* Event horizon
* Photon sphere
* Innermost stable circular orbit
* Ergosphere
* Penrose process
* Blandford–Znajek process
* Accretion disk
* Hawking radiation
* Gravitational lens
* Bondi accretion
* M–sigma relation
* Quasi-periodic oscillation
* Thermodynamics
* Immirzi parameter
* Schwarzschild radius
* Spaghettification

Issues|

* Black hole complementarity
* Information paradox
* Cosmic censorship
* ER=EPR
* Final parsec problem
* Firewall (physics)
* Holographic principle
* No-hair theorem

Metrics|

* Schwarzschild (Derivation)
* Kerr
* Reissner–Nordström
* Kerr–Newman
* Hayward

Alternatives|

* Nonsingular black hole models
* Black star
* Dark star
* Dark-energy star
* Gravastar
* Magnetospheric eternally collapsing object
* Planck star
* Q star
* Fuzzball

Analogs|

* Optical black hole
* Sonic black hole

Lists|

* Black holes
* Most massive
* Nearest
* Quasars
* Microquasars

Related|

* Black Hole Initiative
* Black hole starship
* Compact star
* Exotic star
* Quark star
* Preon star
* Gamma-ray burst progenitors
* Gravity well
* Hypercompact stellar system
* Membrane paradigm
* Naked singularity
* Quasi-star
* Rossi X-ray Timing Explorer
* Timeline of black hole physics
* White hole
* Wormhole

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