4 ms·
Somewhat related https://what-if.xkcd.com/17/ https://what-if.xkcd.com/17/ The surface is too small and you only get like 4% of the energy you need (Assuming y
by gus_massa 7mo ago
Somewhat related https://what-if.xkcd.com/17/ https://what-if.xkcd.com/17/
The surface is too small and you only get like 4% of the energy you need (Assuming you like being naked under full sunlight all day long. The article is for cows, but I guess the number is similar for humans.) 4% of 2400 kcal is almost 100 kcal, that is the content of a small diet treat or 2 apples.
These sea slugs can survive because they move very slowly. For a human, I think it's not enough energy to survive even if all the activity is to watch TV inside a hot swimming pool.
- eigenspace 7mo agoDietary need scales with volume, whereas incident sunlight would scale with surface area. Assuming a spherical cow and a spherical human, the calories needed would scale with the radius cubed, whereas the calories gained from sunlight would scale with the radius squared. So while I agree this wouldn't be very many calories, even if you sat under the sun all day, I think the 4% figure is probably quite pessimistic.
- pfdietz 7mo agoThe square cube law pops up all over the place, my favorite being in fusion reactors, where it is a two edged sword.
- KnuthIsGod 7mo agoMarvelous... Finally a good reason to assume a spherical cow!
- gus_massa 7mo agoMmm... Cows weight like 5 persons, 5^(1/3)=1.7, so 4%*1.7=7%, so 170 kcal that is still less than a single cheeseburger.
- deleted 7mo ago[deleted]