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So imagine a black hole that is like 3 times the mass of the sun so that there can be a bigger gravitational gradient. Assume the black hole has no accretion disk, charge, or rotation for simplicity's sake. So my idea is to imagine building a spherical shell of graphene around 4 Schwarzschild radii away from the black hole fully surrounding the black hole. (This is probably unrealistic practically speaking but I want to know whether this mechanism can theoretically be used to extract energy from the black hole). So that after that is built, we can attach multiple graphene rods that attach from the graphene shell which contains multiple protons and neutrons.

Now, this is where the energy generation part comes in. So the black hole's gravity could stretch those protons and neutrons which would pull apart quarks from one another. At some point, new quark pairs will form. Then let's say the graphene shell could absorb the mesons and once the meson decays the energy could be absorbed into the shell and could probably be used for whatever.

*This is obviously for theoretical purposes and in practice, this would be a massive engineering feat.

*Also the reason graphene was chosen was that graphene is a very strong material so maybe it can survive some of the extreme conditions that it will have to go through.

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    $\begingroup$ It is possible to extract the energy of the particle swallowed by the black hole, but not the black hole itself, see tinyurl.com/4xbpzt9u but the idea that graphene would be strong enough to keep its structure until the quarks are ripped off is ridiculous, the graphene will already break when the electric forces are overcome, let alone the strong force between the Quarks. $\endgroup$
    – Yukterez
    Jul 21, 2022 at 11:03

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Even if what you are proposing here could work (which, as Yukterez pointed out in a comment, it couldn't), you wouldn't actually be extracting energy from the black hole. Instead, you are simply proposing to extract the gravitational potential energy released by something falling toward a massive object (which need not be a black hole), which will ultimately lead to some energy going into that massive object. Of course, it is possible to extract energy this way, as seen in hydroelectric power plants.

Regarding the question in the title, as far as I am aware (although I am not an expert in black holes), it is not possible to extract energy from a non-rotating black hole, although Hawking radiation can decrease its energy. However, it is possible to extract energy from a rotating black hole via the Penrose process, in which an object enters the black hole's ergosphere, deposits some negative energy, and then leaves the ergosphere with more energy than it entered with. This is possible because a rotating black hole has negative energy states within its ergosphere that are also outside of its event horizon.

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  • $\begingroup$ How is it not possible to just keep the object stationary at a certain orbit and just let the very high gravitational gradient separate the quarks? Then it can be possible to extract the energy of the new quarks produced right. $\endgroup$ Jul 23, 2022 at 22:29

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