I found this video on youtube an wonder if it’s all true? https://youtu.be/pprplcYO4fw?si=aUr5m-baVEUAUh4n
What if humans could photosynthesize?
r/whatif
I found this video on youtube an wonder if it’s all true? https://youtu.be/pprplcYO4fw?si=aUr5m-baVEUAUh4n
Comments
Have you even tried?
We already do. We use sunlight to make vitamin D.
But the problem with photosynthesizing for food is we wouldn’t be able to make anywhere near enough food. You’d have to be the size of a copse of trees to get enough calories, which would make you too large to move.
In one study I saw, the amount of energy from photosynthesis is very much less than energy from digestion. That’s why animals tend to move and plants tend not to. Plants don’t get enough energy from photosynthesis to allow them to move.
Try making a lizard or insect that can photosynthesise instead. It has a greater ratio of surface area to volume.
Damn you square cube law!
I think it’d be a game-changer but not how we might imagine. Photosynthesis is such a slow process when you think about it in terms of energy output. I’d bet you’d still need to eat because what you’d get from photosynthesizing is probably like, snack-level calories at best. So no major skipping meals. Maybe you’d have a shady nap outside and look like somebody’s fancy houseplant? Imagine how much sunscreen you’d need to keep from burning to a crisp while soaking up the sunlight for hours. I lived in Hawaii for a bit, and some days, the sun is just ruthless, so that doesn’t sound as fun as one might think. Also, good luck being productive during the winter if you live up north where sunshine can be in short supply. Bottom line, unless our bodies could dramatically increase efficiency, you’d need a salad to go with your sunlight.
The video is drastically underselling the problems.
That figure off 200cal a day? Yeah, that’s a big ass tree taking all day to accomplish. Which means you’d have to be 10x the size of a tree, 100x-1000x bigger and only consume the same amount of energy you do now.
It’s like buying a hand-held solar panel to trickle charge your hybrid car…..like….why?
Taking a page from the world of sci fi, but I can see a use case for photosynthesis as a survival mechanism. You would go into a low metabolism/coma/hibernation state and photosynthesis would provide enough energy to keep you alive.