Eating radioacitivity and electricity

[Accelerator]

So I was thinking of a human in space thing.

Is there any mechanism by which human sized, human shaped, human descended living creatures can survive off radiation, radio waves, or other kinds of electromagnetic force?

One idea I had: insert genes so humans can withstand immense amounts of radiation.

Like

https://en.m.wikipedia.org/wiki/Deinococcus_radiodurans

Add in radiographic fungus that is symbiotic to us. Lives right next to our skin. Absorbs radiation from space, and produces sugars that we can use.

[Fyraltari]

Genetics isn’t LEGO. You can’t just isolate the gene of something, inject it into some creature’s génotype and *poof* you’ve got a an octopus with wings. Gene expression is an abysmally complex web of interactions.

[Grey_Wolf_c]

So I was thinking of a human in space thing.

Is there any mechanism by which human sized, human shaped, human descended living creatures can survive off radiation, radio waves, or other kinds of electromagnetic force?

Sure. Construct a machine that isolates and concentrates those sources of energy . Insert some form of material in a raw state that would be difficult to digest, and bombard it with energy until it becomes edible. Ta-da! now humans in their current state survive by using those sources of energy. Heck, I've been using this space-age machine called "microwave" due to the high-frequency electromagnetic waves it employs for this very purpose. I can report it works quite well. It also does popcorn.

Grey Wolf

[OutOfThyme]

D. radiodurans has redundancies built in that allow it to repair its chromosomes - at least, that's how I understand it. I'm no biologist or zoologist, so I really don't know the specifics.

But biological protection against ionizing radiation can really only come in that form, since ionizing radiation directly attacks nucleotides (someone please provide more detail on this, I'm woefully out of my depth here).

It's probably a lot easier to design suits that are resistant to radiation than that.

[Kato]

I think GW is a bit overly dismissive but as others pointed out, it's not that simple.
That bacterium is not feeding on radiation, it's just very resilient.

Just in theory it might sound possible, after all photosynthesis is just a complicated way to turn sunlight into sugar, which is also just em radiation. But putting aside how complex that process is, 'cosmic radiation' is harder to process because it is much more energetic and therefore tends to destroy molecules not just give them a good shot of energy, be it proteins, DNA or whatever. (we care a lot about the DNA because we really need that to not be busted)
So you'd not only need a protein that actually can absorb the energy, it should also shield everything else from being broken by it. And it better absorb a large part of the spectrum.

It might seem possible on paper but I don't think it stands up to reality.

[Analytica]

So I was thinking of a human in space thing.

Is there any mechanism by which human sized, human shaped, human descended living creatures can survive off radiation, radio waves, or other kinds of electromagnetic force?

One idea I had: insert genes so humans can withstand immense amounts of radiation.

Protect most of the body by a shell which keeps radiation out. Have special membrane-like organs that grow on top of this shell that absorb the energies.

Sure, synthetic biology is not trivial for us now. But your sci-fi civilization may have the technology for it.

[Radar]

I think GW is a bit overly dismissive but as others pointed out, it's not that simple.
That bacterium is not feeding on radiation, it's just very resilient.

Just in theory it might sound possible, after all photosynthesis is just a complicated way to turn sunlight into sugar, which is also just em radiation. But putting aside how complex that process is, 'cosmic radiation' is harder to process because it is much more energetic and therefore tends to destroy molecules not just give them a good shot of energy, be it proteins, DNA or whatever. (we care a lot about the DNA because we really need that to not be busted)
So you'd not only need a protein that actually can absorb the energy, it should also shield everything else from being broken by it. And it better absorb a large part of the spectrum.

It might seem possible on paper but I don't think it stands up to reality.

Even on paper it is next to impossible, since whatever a molecule absorbs without breaking has to have its energy lower then that of each molecular bond within the molecule. There is a pretty hard cap on those as far as I know, since we are mostly worried about valence elecrons (which build the bonds), which do not feel the full pulling force of the nucleus anyway.

Therefore, in order to absorb X ray for a long time you need something that can deal with being ionized on a regular basis. Most likely a slab of metal will be much better at it then a sophisticated molecule, since the internal structure does not depend on any particular bond, so you can loose quite a lot of them before there are problems and regaining balance is considerably fast, since the kicked off electron will be quickly scattered and reabsorbed before they escape the bulk of the shield.

For gamma rays, the ineracting part of matter is usually the nucleus (although ionization cascades are also possible). Essentially, the heavier and more tightly packed atoms, the better. This is exactly why lead is the meterial for radiation shields. There is also the important detail that lead is very stable, so a gamma ray is unlikely to break the nucleus to pieces. Organic matter as we know it would not cut it.

[Peelee]

Sure. Construct a machine that isolates and concentrates those sources of energy . Insert some form of material in a raw state that would be difficult to digest, and bombard it with energy until it becomes edible. Ta-da! now humans in their current state survive by using those sources of energy. Heck, I've been using this space-age machine called "microwave" due to the high-frequency electromagnetic waves it employs for this very purpose. I can report it works quite well. It also does popcorn.

Grey Wolf

You should get a bigger science machine for bigger materials, like I have.

[Accelerator]

What about electricity?

[Craft (Cheese)]

You can always harness energy from radiation the dumb way: Blast some water with it until it heats to boiling, then use the boiling water to turn a good old-fashioned steam turbine. There might be some "minor engineering concerns" doing this with the randomly distributed ambient radiation you find out in space, rather than with a controlled artificial source.

And by "minor concerns" I mean this is so close to impossible you're almost certainly better off just shielding your spacecraft instead.

As for "what about electricity" there's no way around the fact that our cells only accept ATP as energy sources (every other form of stored energy in our bodies is converted into ATP before use), and you're not going to change that without turning us into brain uploads running on android platforms. So barring that, it'll come down to some scheme for growing food on the ship, using recycled waste as fertilizer. Much smarter folks than me have really thought this through and ultimately without lugging around a full planet with us the system just cannot run indefinitely: 100% waste reclamation is impossible so it's only a matter of time before you run out of materials to turn into food.

[Radar]

You can always harness energy from radiation the dumb way: Blast some water with it until it heats to boiling, then use the boiling water to turn a good old-fashioned steam turbine. There might be some "minor engineering concerns" doing this with the randomly distributed ambient radiation you find out in space, rather than with a controlled artificial source.

And by "minor concerns" I mean this is so close to impossible you're almost certainly better off just shielding your spacecraft instead.

As for "what about electricity" there's no way around the fact that our cells only accept ATP as energy sources (every other form of stored energy in our bodies is converted into ATP before use), and you're not going to change that without turning us into brain uploads running on android platforms. So barring that, it'll come down to some scheme for growing food on the ship, using recycled waste as fertilizer. Much smarter folks than me have really thought this through and ultimately without lugging around a full planet with us the system just cannot run indefinitely: 100% waste reclamation is impossible so it's only a matter of time before you run out of materials to turn into food.

Still, enclosed ecosystems are actually possible on a small scale.

[Kato]

Well, if you don't care about mass, you can build your spaceships surrounded by huge water "ballons" that absorb radiation and heat up. You'll need to figure out a smart way to turn that into usable energy, though (I don't think you'll get it to boil if you also want enough to be a good shield) but you might get both... somehow. Seems more reliable than the biological approach.

[Chronos]

D. radiodurans might not actually feed on radiation, but C. neoformans (also mentioned by the OP, though not by name) does.

[Kato]

D. radiodurans might not actually feed on radiation, but C. neoformans (also mentioned by the OP, though not by name) does.

While this sounds interesting it's not quite definitive it does. Don't get me wrong, it'd be cool if it did, but the best it says is that it grows faster under radiation. As has been pointed out above, using proteins to harness radioactive energy is very difficult / unlikely, so until there is more conclusive evidence I'd refrain from 'they eat radiation'.

[Vinyadan]

So I was thinking of a human in space thing.

Is there any mechanism by which human sized, human shaped, human descended living creatures can survive off radiation, radio waves, or other kinds of electromagnetic force?

One idea I had: insert genes so humans can withstand immense amounts of radiation.

Like

https://en.m.wikipedia.org/wiki/Deinococcus_radiodurans

Add in radiographic fungus that is symbiotic to us. Lives right next to our skin. Absorbs radiation from space, and produces sugars that we can use.

The aftereffects:

[Knaight]

It's theoretically possible, in a "technically thermodynamics doesn't actually prohibit this" way. You'd need perfect mass containment as this is pretty much a closed cycle by necessity, and as far as biological organisms go there's obvious problems around reproduction (extra mass needs to come from somewhere) - but hypothetically at the single organism level this is doable. Mass balance works (zero in, zero out), energy balance works, we know that light and electricity can both be used to climb energy gradients in chemical reactions that then work as chemical storage in a metabolism. From a basic theory perspective it's at least viable.

Theoretically possible and hypothetically doable is not remotely the same thing as actually feasible to do. This starts with something along the lines of photosynthesis working with a significantly worse radiation band for energy gain, needing vastly better efficiency than humans have on the energy use end, and some sort of perfect containment system for a skin that also contains the chemistry for radiation harvesting. That's just the energy side - the mass side is even worse. All that oxygen people normally breathe? All that CO2 normally exhaled? There's no atmosphere to dump it in or take it from. Same with water, same with everything else.

Basically, instead of just using a space suit we'd need to figure out a bunch of unfamiliar chemistry, then figure out how to biologically produce it using systems that are not only unfamiliar and unknown but are analogous to things that are barely understood as is. We need to make tools we don't know so we can use tools we don't know to make complicated systems we don't know out of parts we don't know. Not only is there a very real possibility that it turns out it's not possible to do at all due to something more particular than basic physics, it being physically possible doesn't mean humans will ever get anywhere near the technology involved. Assuming we will we're so far behind we can't even guess at how far behind we are.

[khadgar567]

@accelerator misaka worst called just a minute earlier says aiwass thinks you are going crazy and she asks are you free on weekend for double date with touma.

[Eldan]

I mean, the generally accepted way to biologically turn radiation into chemical energy is photosynthesis.

By which I mean: either grow plants on your ship or have humans that photosynthesize.

Of course for your humans to photosynthesize, they'd probably have to drag a giant skin sail behind them. (Back of the envelope estimation: you a small field to plant enough plants to feed a human. Your human would have about the same area of green skin explosed to light at all times as the combined area of all the leaves on that field.)

[Vinyadan]

I mean, the generally accepted way to biologically turn radiation into chemical energy is photosynthesis.

By which I mean: either grow plants on your ship or have humans that photosynthesize.

Of course for your humans to photosynthesize, they'd probably have to drag a giant skin sail behind them. (Back of the envelope estimation: you a small field to plant enough plants to feed a human. Your human would have about the same area of green skin explosed to light at all times as the combined area of all the leaves on that field.)

Do leaves have the most efficient shape for catching sunlight?

[Eldan]

Not necessarily, since they have to perform other functions like gas and water exchange too and also have to be wind-resistant, but they are still pretty optimized. But I did suggest one giant skin flap for our photosynthetic humans (maybe a foldable sail?), rather than them carrying a few trees around on their back, so shape would be different anyway.

[Grey_Wolf_c]

Not necessarily, since they have to perform other functions like gas and water exchange too and also have to be wind-resistant, but they are still pretty optimized.

I have heard from sources I don't fully trust (or remember) that green is probably the worst possible colour for photosynthesis, since the plants are reflecting most of the sun's bandwidth by reflecting green (this goes hand in hand with "the sun is technically green since even though it emits in all frequencies, it emits its highest level in the green band", which is another thing I have heard on the Internet and have no idea if it is true). The explanation is that the current green plants evolved to fill a niche not occupied by red/blue photosynthesizers.

Is any of the above in any way accurate? If so, would the human flap be engineered to be smaller if it was, say, black so it didn't fail to capture light?

Grey Wolf

[Fyraltari]

I have heard from sources I don't fully trust (or remember) that green is probably the worst possible colour for photosynthesis, since the plants are reflecting most of the sun's bandwidth by reflecting green (this goes hand in hand with "the sun is technically green since even though it emits in all frequencies, it emits its highest level in the green band", which is another thing I have heard on the Internet and have no idea if it is true). The explanation is that the current green plants evolved to fill a niche not occupied by red/blue photosynthesizers.

Is any of the above in any way accurate? If so, would the human flap be engineered to be smaller if it was, say, black so it didn't fail to capture light?

Grey Wolf

The sun is yellow. I didn't think anybody would try to contest that. Not only can you see that it is yellow, but this is alwo why it is harder to make yellow out of a white background: our brain is used to treat yellow as the neutral, ambient light.

To be precise the sun is a G-type main sequence star, informally called "yellow dwarf".

Upon further reading it turns out the sun does peak in the green-blue band but the blue atmosphere means it evens out at yellow. Uh. Did not know that.

[Eldan]

I have heard from sources I don't fully trust (or remember) that green is probably the worst possible colour for photosynthesis, since the plants are reflecting most of the sun's bandwidth by reflecting green (this goes hand in hand with "the sun is technically green since even though it emits in all frequencies, it emits its highest level in the green band", which is another thing I have heard on the Internet and have no idea if it is true). The explanation is that the current green plants evolved to fill a niche not occupied by red/blue photosynthesizers.

Is any of the above in any way accurate? If so, would the human flap be engineered to be smaller if it was, say, black so it didn't fail to capture light?

Grey Wolf

Sort of, if we are thinking purely in terms of taking in the most energy, then yes, yellow and green would be the most efficient light. It's a bit more complicated than that, though. The plants don't just need any light. They need two narrow bandwidths of light, to activate to distinct chemical reactions with those exact activation energies.

[Grey_Wolf_c]

Upon further reading it turns out the sun does peak in the green-blue band but the blue atmosphere means it evens out at yellow. Uh. Did not know that.

There is a reason why I threw in that "technically" in my post, indeed.

Grey Wolf

[Kato]

I guess the fact that random mutation lead to something like photosynthesis in itself is lucky enough, so asking why it's not optimized is a bit of a high expectation. Then again, it came about in the sea, maybe the way sunlight interacts with seawater is why plants are not perfectly optimized to get the most out of it?
Though, if evolution was perfect we'd have a bunch of processes harnessing all kinds of the spectrum.

[Eldan]

I guess the fact that random mutation lead to something like photosynthesis in itself is lucky enough, so asking why it's not optimized is a bit of a high expectation. Then again, it came about in the sea, maybe the way sunlight interacts with seawater is why plants are not perfectly optimized to get the most out of it?
Though, if evolution was perfect we'd have a bunch of processes harnessing all kinds of the spectrum.

You wouldn't want that. Again, the two wavelenghts needed are fairly narrow and using them requires dozens of steps and a Lot of machinery.

Replicating every step a dozen times in parallel with slight differences so you can use a half dozen more frequencies would be hugely inefficient.

As vague analogy, imagine a car with four füll engines, to use gasoline, Diesel, kerosine and hydrazine in parallel. Huge, expensive and cumbersome.

[Kato]

You wouldn't want that. Again, the two wavelenghts needed are fairly narrow and using them requires dozens of steps and a Lot of machinery.

Replicating every step a dozen times in parallel with slight differences so you can use a half dozen more frequencies would be hugely inefficient.

As vague analogy, imagine a car with four füll engines, to use gasoline, Diesel, kerosine and hydrazine in parallel. Huge, expensive and cumbersome.

Ah, but your comparison is lacking because I have to buy the fuel, the plant gets light for free. I mean, I guess if one normal plant used all of the sunlight at once it wouldn't know what to do with all the energy but if it had evolved to make better use of that it could drastically increase growth.
And it's not just half a dozen, think of all the wavelength un-used by plants. What a waste of energy!

[Radar]

Ah, but your comparison is lacking because I have to buy the fuel, the plant gets light for free. I mean, I guess if one normal plant used all of the sunlight at once it wouldn't know what to do with all the energy but if it had evolved to make better use of that it could drastically increase growth.
And it's not just half a dozen, think of all the wavelength un-used by plants. What a waste of energy!

Even if you did not need to buy fuel, you would need to fit four engines in. The same goes for plants: any space used for auxiliary photosynthesis systems is space not used for the primary energy source. Still, the plants are not confined to just chlorophyll anyway (see wiki). For some reason none of them can utilise green light. Maybe there are some chemical problems with converting this specific ammount of energy into ATP.

[Kato]

Huh, I didn't know there were that many photosensitive pigments already (also, it's weird to consider two blue-green and yellow-green and then claim none are green)
I mean, I feel like I should have known but I didn't.
But still, there's still much untapped. Infrared! Ultraviolet! Be more efficient, you lazy chloroplasts !

(and yes, I know there are reasons but I can still complain)

[DavidSh]

(also, it's weird to consider two blue-green and yellow-green and then claim none are green)

The claim I see is that none absorb well in the green-yellow region. It's perfectly normal for a X color pigment to not absorb X color light -- you assign the color of a pigment by the color of the light it reflects, not by the color of the light it absorbs.