Photosynthetic hero-thing question.

What do you imagine it would feel like to be a photosynthetic human when the processes are at work? Let's say it would be capable of generating enough energy to be noticeable to a person; my story pretty much runs on comic book physics anyway.

Answers don't have to be elaborate if you don't want; I can elaborate from even just a little insight.

Thanks!

First you have to consider photosynthesis converting CO(2) to O(2). In a greenhouse place where the trees don't shine, would be where such a person is content. Also, you need light. It does not matter if it's from the sun (though that would be optimal), or if its from a lightbulb. But mere lightbulbs to a phoyosynthetic-person is like eating just only a bag of pretzels.. per week.

Of water, your hero needs to drink lots, and lots of this if he is going to get enough energy for a day. Perhaps the other processes can substitute other compounds (such as arsenite) for water in the electron-supplying role. Do remember your hero (if he is a human[like]) needs much more energy than the usual tree or flower, especially moving around and thinking.

Then you need the nutrients — like nitrogen, potassium, those found in fertilized soil. I think your hero can eat dirt. Or a suitable nutrition pill, if these exist in your story.

edited 6th Mar '11 1:44:25 PM by QQQQQ

He is anywhere from a human to a mad science-created humanoid.

And do you mean that the difference between the sun and lightbulbs would be that big, or that light in general wouldn't provide very much for him?

Photosynthesis simply isn't that efficient a reaction, AFAIK.

And do you mean that the difference between the sun and lightbulbs would be that big, or that light in general wouldn't provide very much for him?

I can tell you that light (or photon energy) is a necessary component of photosynthesis. Each photon providing a tiny bit of energy.

Although it is a vast oversimplification to state the average output is 500 nm, it is true that our sun emits 383 yottawatts (3.83x10^26 W) per second - which would yield 10^45 photons of 500 nm light. In reality, many of the photons generated are absorbed and re-emitted again at lower energies. This makes calculation of the actual number generated, absorbed, and generated again nearly impossible. In comparison with the 200 or 40 watts designation of a single lightbulb.

Or to say Yej again:

Photosynthesis simply isn't that efficient a reaction, AFAIK.

edited 6th Mar '11 2:34:08 PM by QQQQQ

I think it's generally assume that the Earth gets 1kW/m^2 of sunlight, which would make calculating the gain a little easier.

To add to QQQQQ's first post. Photosynthesis occur at a wet surface in contact with air so it could obtain carbon dioxide and exposed to light. This, of course, translate to water loss. Another reason for requiring large amount of water.

Guys, he didn't ask if it was possible or reasonable (he mentioned comic book physics, for cryin' out loud), he asked what it would feel like.

I imagine that it'd be somewhere between sleeping (but without being unconscious?) and eating. Photosynthesis produces useable energy. It would be relatively small compared to eating actual food, but it would be a steady stream as long as they had light, air, and water.

I imagine a photosynthetic human would walk around during the day naked to soak in as much sunlight as possible.  ^*

Can he / she still get energy from eating food, or does he / she rely solely on photosynthesis?

Photosynthesis or photovoltaic? The former converts CO 2, water and certain other nutrients into organic compounds to build tissue. The later converts light into electricity, which seems far more interesting if you also have a built in way to store and use that energy.