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The sun's power density is approximately the same as compost.
by evanb 3y ago
The sun's power density is approximately the same as compost.
- drewrv 3y agoCan you elaborate on that or drop a link that explains more?
- s1artibartfast 3y agoLive/fresh compost creates heat as a byproduct of cellular metabolism during decomposition. I assume this is is using thermal output of this compost as a measure of energy. What more do you want to know.
- mr_toad 3y agoThe rate of fusion in the Suns core is actually very slow and gram for gram it is not producing much energy. But the core of the Sun is well insulated by the vast bulk of itself, so even a slow release of energy builds up to extreme temperatures. https://en.wikipedia.org/wiki/Sun#Structure_and_fusion https://en.wikipedia.org/wiki/Sun#Structure_and_fusion
- evanb 3y agoHere's a decent stackexchange discussion: https://physics.stackexchange.com/questions/370899/suns-power-density-compared-to-a-compost-heap https://physics.stackexchange.com/questions/370899/suns-powe...
- worldsayshi 3y agoSo does that mean that making a fusion reactor makes as much sense as building a containment vessel for a compost reactor?
- lajy 3y agoStars have to have enough mass to have enough gravity to start and sustain a nuclear reaction that constantly blasts energy out in all directions. This limits just how energy-dense they can get. What they lack there, they make up for in size and lifespan. We can make sustained nuclear reactions in much less space using engineered pressure instead of gravity, so that skews the energy density ratio.
- bmitc 3y agoThe Sun uses gravity, due to its mass, for fusion containment. Fusion reactors on Earth use electromagnetic containment.
- hermitcrab 3y agoFusion only happens in the Sun due to incredibly rare quantum tunnelling events. That is why the sun can burn for billions of years. It takes a long time for the energy generated to reach the surface and escape, that is why the sun has a high temperature. IIRC fusion reactors on earth use magnetic confinement to raise the temperature much higher than the sun's interior for a much higher rate of fusion reactions. I'm sure someone will be along to correct me if I got that wrong. ;0)