I am currently building a planet that weighs about 4 earth masses and is 2.3 earth radii long. It is an ammonia planet (as the title suggests), and has ammonia oceans with some dissolved water ice, methanol and salts (sodium, chlorides, sulfates, potassium etc.). The average temperature is about 260ºK on the planet and the avg pressure at sea level is about 2.5 atm.

Here is the composition of the atmsophere:

  • Nitrogen: 66%
  • Ammonia: 19.8%
  • Methane: 7%
  • Neon: 5%
  • Argon: 1%
  • Ethylene: 0.9%
  • Propylene: 0.2%
  • Others: 0.1%

I have also been building plants that use light energy to produce energy for themselves. I found this question that talks about different reactions and I settled on two reactions that produce energy: $2 NH_3 + C_2H_4 + Energy → N_2H_4 + 2 CH_4$ and $2 CH_4 + Energy → H_2 + C_2H_6$.

However, both of these reactions require energy, and I am getting that energy from the star. That means that I need some sort of chemical that easily converts light energy from the star (G5V).

So, would I need an alternative chemical that converts light energy to chemical energy (like what chlorophyll does on earth)? If so, what would be some likely candidates for this purpose?

Thanks in advance.


1 Answer 1


It would be different.. all you need is reaction chambers for the ammonia, so you get black(optimal heatbinding) insulated leafs- soaking up maximum heat for processing.. Think of hair, to prevent heat loss.

Such a system would be almost cell dead - as in the leaf expands alive, stores the processing agents and then dies controlled, the only living cells being some sort of root in the stem that extracts the final product from the reaction, growing into the dead tissue of the leaf. Ocassional spontanous breaking down of the leaf structure upon "overheating" would be an issue.

  • 1
    $\begingroup$ Interesting idea. The whole thing about the leaf dying after it creates the energy. I also will make these leaves absorb some red/orange/yellow/green visible light and also a lot of the infrared spectrum to absorb more heat from the star (the plant could also then look blue, purple, and/or black). I'll probably make this one type of plant. $\endgroup$
    – Neil Iyer
    Commented Mar 22 at 15:08
  • 1
    $\begingroup$ +1 I like this idea because the assumption that life on an Ammonia planet would be anything like life on Earth (and, thus, we look for a direct replacement for chlorophyll) is very unlikely to be true. More likely is that a completely different mechanism would evolve that takes advantage of the properties of Ammonia, and that's the idea presented here. Cheers. $\endgroup$
    – JBH
    Commented Mar 22 at 17:12

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