Membrane Paradigm - Hawking Radiation

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 the event horizon (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 event horizon, 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 event horizon 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".