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The Unreasonable Efficiency of Black Holes

The Unreasonable Efficiency of Black Holes

minutephysics
2 HN recommenders · discussed 2020–2025
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About this video

Minutephysics compares how efficiently different processes convert mass to energy per E=mc^2, from fire and fission to fusion, antimatter and black holes, which can convert a large fraction of mass to energy.

Why it appears in the archive

Linked as a quick, clear primer when black hole energy and efficiency come up.

AI-generated summary and labels from the source dataset; verify important details against the video. Source & credits.

From the Hacker News discussion

willis936 · 2020-05 · rec

I don’t see why it’s unbelievable. High mass energy conversion is one of the least crazy things about black holes imo. For readers who want some quick info: [VIDEO] This PBS SpaceTime video doesn’t talk about the practical uses of Kugelblitzes, but it isn’t a big leap from understanding what they are to how to get energy out of them. Hawking radiation rate increases as schwarzschild radius decreases. If you could make a properly sized black hole you could convert a little bit of mass into a lot of energy. Maybe this could be harnessed to solve all electricity demand issues. Maybe it could be used to make a room sized bomb that blows up Earth. Vote now on your phones. [LINK]

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jerf · 2021-10 · rec

Well, that very nearly is the method of power generation. It would presumably be paired with some sort of Dyson sphere around the white dwarf. (Remember that a "Dyson sphere" isn't necessarily a solid shell, but just some configuration of matter where no matter which direction the energy goes it is intercepted by something.) You may also enjoy: [VIDEO] which is a minutephysics on black hole power using much the same principles but attaining yet higher efficiencies.

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pantalaimon · 2025-07 · reference

> minus a few percent to gravitational waves They actually convert up to 42% of their mass into energy, mostly radiation [VIDEO]

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