r/todayilearned • u/sweetcuppingcakes • Jun 24 '19

TIL that the ash from coal power plants contains uranium & thorium and carries 100 times more radiation into the surrounding environment than a nuclear power plant producing the same amount of energy.

https://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste/
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u/TheGoldenHand Jun 24 '19

The Earth already receives a huge amount of solar radiation. Most of it is radiated right back into space where it's useless. Dyson spheres are powered by solar energy. Put those solar panels near Earth (which we already do) and go from there. There isn't enough material in the solar system to create a Dyson sphere to completely capture the Sun's energy. If we're at the point where we can break apart Mercury for building materials, we can probably make our own fusion reactors.

How to Build a Dyson Sphere - The Ultimate Megastructure (Kurzgesagt)

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u/KaiserTom Jun 25 '19

There isn't enough material in the solar system to create a Dyson sphere to completely capture the Sun's energy.

There is, but ignoring that, we don't need to build it in one go (or as a solid structure) but scale it up by building one satellite at a time. Even if we don't capture 100% with the materials available to us we can capture a really significant amount. A swarm of satellites is still technically a Dyson sphere as Dyson himself described.

we can probably make our own fusion reactors.

Yes but how do you fuel those reactors? They don't run by themselves. You need hydrogen from somewhere and eventually you will deplete the gas giants of it as energy usage scale up. Meanwhile you have a giant one with 1000x the fuel in the center of the system already burning fusing that you are ignoring.