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?
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For some reason, the topic of really big rocks came up at dinner the other night, and SteelyKid declared that she wanted to find "A rock as big as the solar system." We pointed out that that was pretty much impossible, more or less by definition, rocks being sub-parts of the solar system.
I feel dense for not knowing this important public health fact: women with extremely dense breast tissue are at least four times more likely to develop breast cancer.
I previously talked about measurements (some) when I looked at the uncertainty in the distance to the Sun.
I am still thinking about the Red Bull Stratos Jump. Sorry, but there is just tons of great physics here. Next question - how big of a balloon would you need to get up to 120,000 feet?
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.
Our actual output of energy is rather low, unfortunately.
Have you tried that calculation with a B class star? Or a couch potato?