How does the energy release rate of hydrogen fusion compare to the energy released by gravitational contraction?
Answer
Fusion releases energy at a much higher rate, proportional to high powers of core temperature
Hydrogen fusion is incredibly potent, releasing energy at a rate proportional to the fourth or higher power of the core temperature, leading to lifespans of billions of years. Gravitational contraction follows much simpler physics and yields energy less efficiently per unit time.
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