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How to mine energy from a black hole


We describe a process by which energy literally can be mined from a black hole. We argue that the only limit placed by fundamental considerations on the rate at which energy can be extracted from a black hole by this process isdE/dt ∼ 1 in Planck unitsG = c = ħ = 1. This is far greater than the ratedE/dt ∼ 1/M2 at which the black hole spontaneously loses energy by Hawking radiation.

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This essay received the fourth award from the Gravity Research Foundation for the year 1982-Ed.

This research was supported in part by the National Science and Engineering Council of Canada, by the Alfred P. Sloan Foundation, and by NSF Grant No. PHY 80-26043 to the University of Chicago.

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Unruh, W.G., Wald, R.M. How to mine energy from a black hole. Gen Relat Gravit 15, 195–199 (1983).

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