Talk:Extremal black hole

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Make paragraph or page: smallest black hole in astronomy

The article isn't about it, but we should mention the observational facts as a reference (also facts are important). — Preceding unsigned comment added by 2A02:587:4104:B0C1:800F:A5C:F7B3:305F (talk) 19:45, 13 July 2020 (UTC)[reply]

Unsource material can be deleted.

I deleted this sentence:

Such black holes are stable and emit no Hawking radiation.^{[citation needed]}

It was reverted by @Stepwise Continuous Dysfunction However it is Wikipedia policy that The burden to demonstrate verifiability lies with the editor who adds or restores material. Please undo your edit or provide a reliable source. Johnjbarton (talk) 03:43, 20 June 2025 (UTC)[reply]

Statements to this effect are commonplace in the literature. The abstract of Ghosh and Barman (2022) begins, "It is well known that extremal black holes do not Hawking radiate". Giddings and Strominger write: "Consider the theory consisting of Einstein gravity coupled to electromagnetism. This theory contains charged black hole solutions for which the mass M equals or exceeds, in Planck units, the charge Q. For M < Q, a naked singularity appears. According to Hawking, a quantum mechanical black hole of mass M > Q will evaporate incoherently until it reaches the extremal value M = Q, at which point the Hawking temperature vanishes and the evaporation ceases. Thus the extremal solutions are expected to be the endpoints of Hawking evaporation and correspond to stable quantum groundstates." Bai and Orlofsky (2020) explain as follows: "To stabilize such a light [primordial black hole] against Hawking radiation, one could consider a Reissner-Nordström (RN) BH charged under an unbroken U(1) gauge symmetry. When the magnitude of the U(1) charge |Q| times the gauge coupling is equal to the BH mass in units of the Planck mass, the BH temperature is zero and the Hawking evaporation does not occur. Such a BH is called extremal". Stepwise Continuous Dysfunction (talk) 03:52, 20 June 2025 (UTC)[reply]

Please do not revert such changes in the future. If you have a source, add it. Johnjbarton (talk) 14:34, 20 June 2025 (UTC)[reply]

The only claim in the article about extremal black holes emitting Hawking radiation [1] was inserted by the author of the paper in question [2][3]. It appears to be a non-mainstream proposal that a particular type of extremal black hole can radiate massless, intangible quanta. Most of the citations to this paper are by the author himself, suggesting that it is not a view that we need to stress here. Stepwise Continuous Dysfunction (talk) 04:10, 20 June 2025 (UTC)[reply]