8
$\begingroup$

I've been recently looking into alternative biochemistries for life and the environments were these could be found. I already asked a question about how ammonia oceans might form a while back. Today I'm interested in formamide, as according to a book I read recently, CH3NO

enter image description here

is quite a decent solvent.

Formamide is formed by the reaction of hydrogen cyanide with water; both are abundant in the cosmos. Like water, formamide has a large dipole moment and is an excellent solvent for almost anything that dissolves in water, including polyelectrolytes. In particular, formamide is able to dissolve RNA, DNA, and proteins, as well as their precursors. Formamide is not reactive like water. Indeed, many species that are thermodynamically unstable in water with respect to hydrolysis, are stable in formamide. Formamide is itself hydrolyzed by water, meaning that it persists only in a relatively dry environment, such as a desert. Desert environments recently proposed as being potential sites for the prebiotic synthesis of ribose may hold formamide as well. Since formamide boils at ~400 K, a mixture of formamide and water, if placed in the desert, would lose its water over time and end up as a pool of formamide. Within this pool, many syntheses are thermodynamically favorable: polypeptides from amino acids, nucleosides from sugars and bases, nucleotides from nucleosides and inorganic phosphate, and RNA from nucleotides. Indeed, phosphate esters are also spontaneously synthesized. This includes ATP (from ADP and inorganic phosphate), nucleosides (from ribose borates and nucleobases), peptides (from amino acids), and others.

All of this sounds pretty good, but as with the ammonia oceans, I'm not sure how such an environment could form naturally. The book suggest evaporation of water-formamide ponds in deserts a possibility, but I don't know of any formamide lakes in earths deserts. Also the natural formation of hydrogen cyanide seems to be unlikely, at least in the quantaties required.

I think that hot, water poor desert worlds would be the place fore formamide lakes. Due to the fact that formamide will combust in the presence of oxygen, the atmospere sould lack oxygen as well. So should the planet have a nitrogen or carbon dioxide dominated atmosphere?

How would a hot desert planet have to be made up to form lakes of formamide? Is such a planet likely to form? Biological solutions, like blue green alge producing oxygen on Earth, are allowed as long as they are plausible, though I would prefer geochemical solutions. Terraforming as an answer is out.

$\endgroup$
  • $\begingroup$ the boiling point of foramide depends on the pressure $\endgroup$ – Jasen Nov 12 '19 at 8:28
  • 1
    $\begingroup$ @Jasen Well obviously. But while that does increase the formamide habitable zone, it isn't relevant for the formation of such a planet. $\endgroup$ – TheDyingOfLight Nov 12 '19 at 9:11
  • $\begingroup$ I don't really see how to justify the availability of hydrogen cyanide to begin with. But once you have that, if the temperature and pressure are in a suitable (somewhat rather narrow) range then a mix of water and hydrogen cyanide will indeed equilibrate predominantly with water in the vapor phase and formamide in the liquid phase. $\endgroup$ – Ian Nov 12 '19 at 17:06
  • $\begingroup$ (Cont.) Those temperatures are probably pretty inhospitable to the types of molecules that the life we know about uses, though, even in formamide solvent, so then you have a question of how the water was lost (not to the atmosphere, but from the planet entirely) prior to the planet cooling. $\endgroup$ – Ian Nov 12 '19 at 17:10
  • $\begingroup$ Concerning the temperature of your formamide sea - I don't think it needs to be desertic, or even hot. The source you're quoting only talked about it so that with a mix of formamide and water, the water would evaporate, leaving the just the formamide. $\endgroup$ – Whitehot Nov 15 '19 at 13:45
6
$\begingroup$

Formamide can be formed by the condensation of carbon monoxide and ammonia. https://en.wikipedia.org/wiki/Formamide

A reducing planet with an ammonia / methane atmosphere is plausible. If there is also some water, one could imagine atmospheric water undergoing photolysis to generate a small percentage of free hydrogen and oxygen. Hydrogen will head up and out of the atmosphere but the oxygen might stick around long enough to get busy.

If there is a little bit of oxygen, it would probably react with the methane to form carbon monoxide. This apparently happened on the early earth.

https://www.space.com/carbon-monoxide-indicator-alien-life.html

... researchers used computer models to better understand the atmospheric chemistry of Earth about 3 billion years ago, when our planet's air contained very little oxygen. Microbial life was common on Earth back then, but animal life was a long way off. (The earliest fossils of multicellular organisms date to about 600 million years ago.)

The team's results indicated that CO could have accumulated in significant quantities in those long-gone days, reaching concentrations of around 100 parts per million (ppm), or about 1,000 times higher than current levels.

"That means we could expect high carbon-monoxide abundances in the atmospheres of inhabited but oxygen-poor exoplanets orbiting stars like our own sun," study co-author Timothy Lyons, a professor of biogeochemistry at the University of California, Riverside (UCR), said in a statement.

A percentage of ambient CO could react with ambient ammonia to produce formamide, which precipitates out as the liquid and accumulates. I like the idea of some sort of biological catalyst for this reaction which would account for why it accumulates in a lake - the things synthesizing it live in the lake.


Thinking about why life forms would synthesize form amide - it is easy. The energy.

enthalpy of formation of formamide

https://webbook.nist.gov/cgi/cbook.cgi?ID=C75127&Mask=1E9F

When these life forms catch a CO and hook it to ambient NH3 they get a little bit of energy back each time.

$\endgroup$
  • 1
    $\begingroup$ That seems an unusual type of nest building. usually any chemical synhesisised in bulk and excreted by an animal in the presence of an abundance is a waste product. $\endgroup$ – Jasen Nov 14 '19 at 0:59
  • 1
    $\begingroup$ With only 100ppm CO you won't be producing that much formamide. You need to reach saturation pressure on ground level, to form liquids. $\endgroup$ – AtmosphericPrisonEscape Nov 14 '19 at 16:33
  • 2
    $\begingroup$ @AtmosphericPrisonEscape - this is why I was thinking the formamide would be a waste product. CO2 is only 300-400 ppm yet organisms scavenging it have managed to load our atmosphere with poisonous O2 waste products in only a couple of billion years. $\endgroup$ – Willk Nov 15 '19 at 0:11
  • $\begingroup$ Not sure how much that is in mass tho, vs. the mass of the oceans... $\endgroup$ – AtmosphericPrisonEscape Nov 15 '19 at 12:49
2
+150
$\begingroup$

'Biological solutions, like blue green alge producing oxygen on Earth, are allowed as long as they are plausible'

'Due to the fact that formamide will combust in the presence of oxygen, the atmospere sould lack oxygen as well. So should the planet have a nitrogen or carbon dioxide dominated atmosphere?' - This contradicts the plausibility of blue green oxygen producing algae.

Okay, let's start.

  • Methane should be quite abundant on this planet, your best bet at achieving this is a proficient colonization of your soil with methanogens and anaerobic methanotrophs.

  • Methane available, next is ammonia, gaseous ammonia. Drying soils emit reactive nitrogen such as nitrous oxide and ammonia.

CH4 + NH3 -> HCN + 3H2

  • Hydrogen cyanide available. Limited water (< 25 cm rainfall) will provide the formation of formamide by reaction with hydrogen cyanide.

  • Anoxic atmosphere, presence of oxygen but not in free form.

  • Finally, rather go with blue green cyanobacteria (Microcoleus) rather than blue green algae.

I'm no geophysicist but I hope I helped with chemistry and biology.

$\endgroup$
  • 1
    $\begingroup$ "proficient colonization of your soul" what do you mean by this? The blue green alge were only meant as an example for a biological processes producing chemicals in an amount that changes the environment on an entire planet. Thanks for the answer $\endgroup$ – TheDyingOfLight Nov 15 '19 at 20:54
  • 1
    $\begingroup$ i apologize, that was a typo error, i intended to type soil $\endgroup$ – user70311 Nov 16 '19 at 12:27
  • $\begingroup$ biological processes are possible, but with microorganisms that function in an anoxic environment. These microorganisms need to be able to retrieve oxygen (if needed for survival) from anoxic compounds ( e.g. nitrous oxide). $\endgroup$ – user70311 Nov 16 '19 at 12:31
0
$\begingroup$

During the early stages of the planet, when asteroid and planetoid impacts are common, asteroids containing ammonia/carbon monoxide(in solid form) could impact the planet, releasing it into the atmosphere, or the crust, of the planet. Over time, as the atmosphere develops, the ammonia/carbon monoxide could be released and condensate, forming formamide. To accompany that, asteroids could contain formamide in itself, as it is common in the cosmos. The asteroids impact, and as the planet develops, formamide forms as oceans or lakes. The planet could be within a range of distances for this to happen, as it boils at roughly 260 degrees Fahrenheit, and is a solid at 37 degrees Fahrenheit.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.