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The Unreasonable Efficiency of Black Holes

The Unreasonable Efficiency of Black Holes on HackerTube: recommended by 2 Hacker News commenters across 2 separate months, 2020–2025.

minutephysics

explainer · evergreen

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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 Hacker News recommends it

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

people recommended it
2
separate months
2
strong recommendations
0
discussed on HN
2020–2025
“For readers who want some quick info”
— willis936, May 2020, in “Black hole paradoxes reveal a fundamental link between energy and order”

What HN commenters said

3 Hacker News comments link this video. Each one links back to its thread.

jerfOct 2021Recommends

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: ▶ this video which is a minutephysics on black hole power using much the same principles but attaining yet higher efficiencies.

in “We've spotted a planet surviving its dying star” · View on HN

willis936May 2020Recommends

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: ▶ this 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]

in “Black hole paradoxes reveal a fundamental link between energy and order” · View on HN

pantalaimonJul 2025Cites it

> minus a few percent to gravitational waves They actually convert up to 42% of their mass into energy, mostly radiation ▶ this video

in “LIGO detects most massive black hole merger to date” · View on HN

Topics & tags

Cosmology & astrophysicsFundamental physicsblack holesmass-energy equivalencenuclear fusionaccretionminutephysics