Cute power density factoid, which I owe to Eric Chaisson: humans have far higher power densities than stars.

The solar luminosity is about 4.10^27 W, the mass is about 2.10^30 kg; so the power density is 2.10^-3 W/kg.

Human use ~2800 kcal/day ~ 120 W. Mass is ~80 kg, so 1.5 W/kg.

Isn’t that fun?


  1. #1 Mark Hadfield

    So this means … If we were the size of the sun we’d get *really* hot. And we’d have to eat a *lot*.

    Thanks for that.

  2. #2 uBeR

    Our actual output of energy is rather low, unfortunately.

  3. #3 Lab Lemming

    Have you tried that calculation with a B class star? Or a couch potato?

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