Penrose process
Theoretical method to extract energy from a rotating black hole.
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The Penrose process is a theoretical method for extracting rotational energy from a rotating black hole using the ergosphere region.[1] The maximum energy gain for a single particle decay via the classical process is 20.7% of its mass for a maximally rotating uncharged black hole.[2]
Quick Facts
- Known for
- Energy extraction from rotating black holes
Facts from the source article.
Key facts and history
Sir Roger Penrose theorised the process as a means to extract energy from a rotating black hole.[1] The process uses the ergosphere, where spacetime is dragged faster than light by the black hole's rotation.[1] Any matter inside the ergosphere must move in the direction of the black hole's rotation from an outside observer's view.[1] The maximum energy extraction for an uncharged black hole is limited to 29% of its original mass.[2]
Larger efficiencies are possible for charged rotating black holes.[2] The best energy extraction occurs when the black hole rotates maximally and the object grazes the event horizon.[3] The object must decay into forward and backward moving light packets, with one escaping and one falling in.[3] The black hole's rotation provides the energy that the Penrose process extracts, and this extraction reduces the black hole's spin.[3]
What the cited sources add
The 1983 book "The Mathematical Theory of Black Holes" by Chandrasekhar, published by Clarendon Press, provides the mathematical foundation for the ergosphere details and energy extraction limits.[4][3]
References
- Wikipedia, "Penrose process" (CC BY-SA 4.0), which cites: Penrose, "Extraction of Rotational Energy from a Black Hole", Nature Physical Science, February 1971, p. 177–179; Misner, "Gravitation", W. H. Freeman, 1973; Williams, "Extracting X rays, Ύ rays, and relativistic e<sup>−</sup>e<sup>+</sup> pairs from supermassive Kerr black holes using the Penrose mechanism", Physical Review D, 1995, p. 5387–5427; Cui, "Precessing jet nozzle connecting to a spinning black hole in M87", Nature, 2023, p. 711–715 (we also read that source) en.wikipedia.org
- Wikipedia, "Penrose process" (CC BY-SA 4.0), which cites: Chandrasekhar, "The Mathematical Theory of Black Holes", Clarendon Press, 1983, p. 369; ; Bhat, "Energetics of the Kerr-Newman black hole by the penrose process", Journal of Astrophysics and Astronomy, 1985, p. 85–100 (we also read that source) en.wikipedia.org
- Wikipedia, "Penrose process" (CC BY-SA 4.0), which cites: Chandrasekhar, "The Mathematical Theory of Black Holes", Clarendon Press, 1983, p. 369 (we also read that source) en.wikipedia.org
- Open Library record, ISBN 0198512910 ("The mathematical theory of black holes"). CC0 (metadata); book content not read. openlibrary.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Penrose process (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Penrose process (CC BY-SA 4.0).
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