Membrane paradigm


Membrane paradigm

In black hole theory, the black hole membrane paradigm is a useful "toy model" method or "engineering approach" for visualising and calculating the effects predicted by quantum mechanics for the exterior physics of black holes, without using quantum-mechanical principles or calculations. It models a black hole as a thin classically-radiating surface (or membrane) at or vanishingly close to the black hole's event horizon. This approach to the theory of black holes was created by Kip S. Thorne, R. H. Price and D. A. Macdonald.

The results of the membrane paradigm are generally considered to be "safe".

Contents

Electrical resistance

Thorne (1994) relates that this approach to studying black holes was prompted by the realisation by Hanni, Ruffini, Wald and Cohen in the early 1970s that since an electrically charged pellet dropped into a black hole should still appear to a distant outsider to be remaining just outside the critical r=2M radius, if its image persists, its electrical fieldlines ought to persist too, and ought to point to the location of the "frozen" image (1994, pp. 406). If the black hole rotates, and the image of the pellet is pulled around, the associated electrical fieldlines ought to be pulled around with it to create basic "electrical dynamo" effects (see: dynamo theory).

Further calculations yielded properties for a black hole such as apparent electrical resistance (pp. 408). Since these fieldline properties seemed to be exhibited down to the event horizon, and general relativity insisted that no dynamic exterior interactions could extend through the horizon, it was considered convenient to invent a surface at the horizon that these electrical properties could be said to belong to.

Hawking radiation

After being introduced to model the theoretical electrical characteristics of the horizon, the "membrane" approach was then pressed into service to model the Hawking radiation effect predicted by quantum mechanics.

In the coordinate system of a distant stationary observer, Hawking radiation tends to be described as a quantum-mechanical particle-pair production effect (involving "virtual" particles), but for stationary observers hovering nearer to the hole, the effect is supposed to look like a purely conventional radiation effect involving "real" particles. In the "membrane paradigm", the black hole is described as it should be seen by an array of these stationary, suspended noninertial observers, and since their shared coordinate system ends at r=2M (because an observer cannot legally hover at or below the event horizon under general relativity), this conventional-looking radiation is described as being emitted by an arbitrarily-thin shell of "hot" material at or just above the critical r=2M radius, where this coordinate system fails.

As in the "electrical" case, the membrane paradigm is useful because these effects should appear all the way down to the event horizon, but are not allowed by GR to be coming through the horizon – blaming them on a hypothetical thin radiating membrane at the horizon allows them to be modelled classically without explicitly contradicting general relativity's prediction that the r=2M surface is inescapable.

In 1986, Kip S. Thorne, Richard H. Price and D. A. Macdonald published an anthology of papers by various authors that examined this idea: "Black Holes: The membrane paradigm".

See also

References


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Holographic paradigm — The holographic paradigm is a form of quantum mysticism extrapolated from two theories: * That the universe is in some sense a holographic structure proposed by David Bohm * That consciousness is dependent on holographic structure proposed by… …   Wikipedia

  • Black hole — For other uses, see Black hole (disambiguation). Simulated view of a black hole (center) in front of the Large Magellanic Cloud. Note the gravitat …   Wikipedia

  • Kip Thorne — Infobox Scientist name = Kip Thorne image width = 240px caption = birth date = birth date and age|1940|6|1 birth place = Logan, Utah death date = death place = residence = nationality = field = Physics work institution = Caltech alma mater =… …   Wikipedia

  • Мембранная парадигма —     Общая теория относительности …   Википедия

  • Holomovement — The holomovement is a key concept in David Bohm’s interpretation of quantum mechanics and for his overall wordview. It brings together the holistic principle of “undivided wholeness” with the idea that everything is in a state of process or… …   Wikipedia

  • Holographic principle — Holographic Universe redirects here. For the album, see Holographic Universe (album). For the book by Michael Talbot, see The Holographic Universe. String theory …   Wikipedia

  • Toy model — In physics, a toy model is a simplified set of objects and equations relating them that can nevertheless be used to understand a mechanism that is also useful in the full, non simplified theory. * In toy mathematical models, this is usually done… …   Wikipedia

  • Cosmic censorship hypothesis — The weak and the strong cosmic censorship hypotheses are two mathematical conjectures about the structure of singularities arising in general relativity. Singularities that arise in the solutions of Einstein s equations are typically hidden… …   Wikipedia

  • Naked singularity — In general relativity, a naked singularity is a gravitational singularity, without an event horizon. In a black hole, there is a region around the singularity, the event horizon, where the gravitational force of the singularity is strong enough… …   Wikipedia

  • Quasar — This article is about the astronomical object. For other uses, see Quasar (disambiguation). Artist s rendering of ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun[1]. Credit: ESO/M.… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.