I've heard a lot of discussion recently about alternative biochemistries, mostly relating to how chemical life might function in a solvent other than water, so it seems like a thread on alternative 'scaffolding' to carbon might be interesting.

For the sake of argument I'd like to propose a carbon-sulphur mix. Sulphur is a reactive, versatile element, which forms long chains, helixes and rings. It's chemistry is not as versatile as that of carbon, but it forms stable compounds with almost every element and is already an essential element for life as we know it. Many organisms use sulfate as an alternative to oxygen, some use hydrogen sulfide as an alternative to water in primitive photosynthesis, soem use it as a food to be oxidised, and elemental sulphur is a component of two amino acids. On a world with much more abundant sulphur than earth it seems reasonable to speculate that sulphur could be as fundamental to biochemistry as carbon, given that sulphur or its compounds can function as both electron acceptor and donor, and given the number of roles it fills here on earth when available.

I've heard of a nitrogen-phosphorous biochemistry being suggested, does anyone have any more information on that, or any out there (but still chemistry based) ideas of their own?

Disclaimer: I'm not a biochemist, and my knowledge of chemistry is fairly limited so I'm hoping for fun (and educational to my limited knowledge) speculation; if the discussion turns to serious biochemistry I'm likely to run and hide (whilst being very impressed by those who dare to join in).

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For me it's enough for the garden to be beautifull; why do so many want to see fairies at the bottom?

"Many of those people are not getting four when adding two and two; many of them aren't even getting five or twenty-two. They're getting potato."
Gillianren

I suggested nitrogen-phosphorus based life as alternative to carbon. Go to:

My ideas about complex inorganic life

and see the links I put. I made all in powerpoint.

But I'm making a second version of such idea and I'll put that in a new topic, because the second version is better than the first.

And It's more organized.

I think that nitrogen-phosphorus based life also could use carbon for some function. This kind of biochemistry would work well at planets with lower temperatures, and in a reducing atmosphere and in oceans of ammonia or aqua-ammonia. Oxygen to such organisms would be lethal. The atmosphere would be rich in nitrogen, methane or ammonia or any other reducing gas.

Silicon-based life to me is much less versatile than a combination of nitrogen and phosphorus. Silicon and oxygen are too stable, at least in room temperature to allow the formation of any organism.

To me, nitrogen-phosphorus or boron-nitrogen substances are more reactive than carbon-based complexes. And if they are more reactive, they would work well in lower temperatures, allowing metabolism in cold worlds. Their metabolism world be almost as fast as ours, due to such substances.

In the new version you'll also find complex compounds of nitrogen and boron, that could also form orgasnisms. And complex compounds of sulfur too.

That's right. I was trying to remember the thread; it was yours enio. When's the second version coming?

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The second version will come when it's done, because I want to do the best as possible.

Thanks for that enio, I knew I'd seen it somewhere. Can't wait for the next installment!

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For me it's enough for the garden to be beautifull; why do so many want to see fairies at the bottom?

"Many of those people are not getting four when adding two and two; many of them aren't even getting five or twenty-two. They're getting potato."
Gillianren

I've mentioned this before, but you really want to track down an old late-'60s science essay by sci-fi writer (and real-life Professor of Biochemistry) Isaac Asimov.

It outlined alternate biochemistries he thought could work from Mercury to Pluto.

(and isn't anywhere online.... his estate has been really good at keeping his stuff locked up... check the library!)

Well, this work of mine is not based on him, but only on what appeared in my mind.

In that case, why ask? Make them live on space-butterflies and rainbows instead of real science knowledge....

Yeah, me too, but it is my sense that the combinatory capabilities of carbon are orders of magnitude greater than any other element.

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Everyone is entitled to his own opinion, but not his own facts.

Carbon is also so common that it's practically impossible to end up in a situation where something else is the only option. Earth has huge quantities of silicon and carbon available, and while Earth life makes some use of silicon, its basis is carbon...though "carbon/water" might be more accurate. The same goes for water...you're unlikely to get ammonia, for example, without also getting copious amounts of water.

However, remember that most of the universe bears little resemblance to Earth's surface. Physical and chemical properties can change greatly with temperature and pressure...silicon life might be more viable in a high pressure, high temperature world where silica is reasonably soluble and where complex carbon-based molecules are unstable. Any intelligent natives of such a world might consider Earth's surface to be a frigid near-vacuum.

You ideas seem really engaging, enio, but why is this called "inorganic life"?

organism
1: a complex structure of interdependent and subordinate elements whose relations and properties are largely determined by their function in the whole
2: an individual constituted to carry on the activities of life by means of organs separate in function but mutually dependent : a living being

Would this life be unstructured, not consisting of microscopic or macroscopic parts working together?

Inorganic in the sense of lacking any carbon.

But now I'm thinking to do all again in the second version, but this time with carbon, because I saw carbon is everywhere, and if there's no escape to it, it will be impossible to have inorganic life in a cold world (with temperature ranging from -150°C to 0°C).

But even having carbon, the molecules will be different from our biochemistry, because such forms of life I have in mind will develop in an ocean made of primordial soup consisted of water, ammonia, alcohols, maybe hydrocarbons, other organics and some salts. And such creatures would develop in a reducing atmosphere, rich in nitrogen and methane, like the air of Titan, but having more methane.

Life developing in a reducing and cold world (the world I have in mind have average temperature of -50°C). Maybe in this world life will develop faster in shallow sea where there's a lot of hydrothermal vents. And then migrate to surface.

Even being a cold world, it would must have much volcanism or many active geysers or hydrothermal vents, to not finish like Mars. It's a cold, but living world, not a dead Mars, as far as we know.

And such world would have mass similar to Earth or higher.

Sorry for the confusion, but wouldn't your version of life change the meaning of "organic" as only applying to carbon-based life forms? To me, "inorganic life" sounds like viruses or that thing in Andromeda Strain.

Carbon and water are very good at producing life, hence earth, but that doesn't preclude other chemical systems supporting something life like, and even one example of such would change the way we look at the emergence of life. I think that makes the question of non carbon abd water life worth considering, even if it turns out to be incredibaly rare, or inherently limited to very simple forms.

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For me it's enough for the garden to be beautifull; why do so many want to see fairies at the bottom?

"Many of those people are not getting four when adding two and two; many of them aren't even getting five or twenty-two. They're getting potato."
Gillianren

Great post.

So a primordial atmosphere could have had a hydrogen sulfide atmosphere with sulfuric acid water for first beginning of life and after hydrogen sulfide was used up, a necessary change to carbon dioxide and sunlight[the hydrogen sulfide had been used up in biolife forms[primitive bacteria] and in sequestered [percipitated]in water/mud sediments.

Bioatmospheric terraforming on a grand scale perhaps.

But incorporating sulfur majorly into biomolecules is definitely fascinating.

But as I been taught on baut that would have to be carbon deprived solar system.

Since the subject of discussion is the chemical basis of life, using "organic life" to mean "life based on organic chemistry" doesn't seem particularly confusing to me.


I don't think anyone has said in this thread that other systems absolutely couldn't support life or that they're not worth considering...the problem with them is that water and carbon are so common on top of being so biologically useful that it's almost certain that life will use them, so you have to look for conditions where they are less suitable...a high pressure, high temperature water world or deep hydrothermal systems where silicon based biochemistry might be more stable, for example.

Interesting stuff. Any idea what such life would look like? Or is that like asking how long is a piece of string?